218 results on '"POTENTIAL distribution"'
Search Results
2. The effects of P and metal elements in electroless nickel-based alloys on the formation of Ti/Zr conversion coating.
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Hao, Jun-Zhe, Xu, Jia-Jun, Cao, Hai-Lian, Miao, Han, and Xu, Shi-Ai
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X-ray photoelectron spectroscopy , *SURFACE coatings , *ATOMIC force microscopy , *GLOW discharges , *NICKEL phosphates , *METALLIC glasses , *COPPER-titanium alloys - Abstract
The objective of this study was to investigate the effects of P and different metal elements on the formation of Ti/Zr conversion coatings on various electroless nickel-based coatings. Advanced surface analytical techniques, including X-ray photoelectron spectroscopy, scanning electron microscopy, atomic force microscopy, glow discharge optical emission spectrometry, and scanning Kelvin probe force microscope were utilized for comprehensive characterization. The results indicate that P in the electroless Ni-P plated coating had a minor impact on accelerating the formation process of the conversion coating by promoting nickel phosphate generation. However, the presence of Fe in the plating coating promotes the generation of nickel phosphate mainly by changing the potential distribution on the surface, which greatly facilitates the reaction for conversion coating formation. In addition, due to its higher activity compared to nickel, Fe participated in the redox reaction, resulting in a significant change in the composition and thickness of coating. Conversely, Cu did not participate in the redox reaction, but instead promoted the generation and thickening of the conversion coating by slightly changing the surface potential. These insights into the role of P, Fe, and Cu elements provide valuable knowledge for optimizing conversion coatings for specific applications, promising significant practical implications. [Display omitted] • Ti/Zr conversion coating was prepared on different electroless nickel-based alloys. • P in the plated coating is involved in the conversion coating generation reaction. • Fe and Cu alter the potential distribution to impacting the conversion coating. [ABSTRACT FROM AUTHOR]
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- 2024
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3. Effect of an altitudinal gradient on the morphology, molecular identification and distribution of Rhipicephalus linnaei in Veracruz, Mexico.
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Aguilar-Meraz, Pamela, Moo-Llanes, David A., Sánchez-Montes, Sokani, Montes de Oca-Aguilar, Ana C., Romero-Salas, Dora, Cruz-Romero, Anabel, López-Hernández, Karla M., Bermúdez-Castillero, Sergio E., and Aguilar-Domínguez, Mariel
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RHIPICEPHALUS , *IXODIDAE , *BROWN dog tick , *ECOLOGICAL niche , *GENETIC vectors , *NUMBERS of species - Abstract
• The distribution and morphology of Rhipicephalus sanguineus sensu lato varies with altitude, this adaptability can encourage the expansion and survival of the species, and consequently, the risk of transmitting infectious agents. • Identifying the tick lineage helps to know the distribution area and supports the geographical limit that is known so far of both lineages. • The ecological niche in which the species lives helps us to know the factors and conditions that favor the presence of this tick and this can be key to better understanding how they are distributed and what environmental variables influence their presence. Studies of morphological and genetic variation in vector populations across environmental gradients can help researchers to estimate species' responses to climate change scenarios and the potential risk of disease-causing pathogen expansion, which impacts negatively on human health. In this study, we analysed the effect of altitudinal gradients on the phenotypic response of the hard tick of medical and veterinary importance, Rhipicephalus sanguineus sensu lato (s.l.). Specimens of R. sanguineus s.l. were collected from host animals in one of Mexico's regions with high climatic heterogeneity (Veracruz), and geometric morphometric theory was employed to assess the response of three morphological characters to the altitudinal gradient. Additionally, genetic similarity data were provided, and ecological niche models were used to project the climatic distribution in the region. Our results demonstrate that the shape and size of ticks respond to altitude. Molecular identification indicate that all analysed samples correspond to the tropical lineage recently named Rhipicephalus linnaei. According to ecological niche models, the mean annual temperature contributes significantly to the spatial distribution of this tick species, with areas of higher suitability in the mountainous region. These changes in morphological structure and the presence of ticks at higher altitudinal gradients suggest that R. linnaei has a high potential for adaptation. Due to the variability of ecosystems in the state of Veracruz, our results could be valuable in assessing the response of this tick in a changing environment, aiding in predicting future scenarios in the distribution and abundance of this species. [Display omitted] [ABSTRACT FROM AUTHOR]
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- 2024
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4. Species distribution models to predict the impacts of environmental disasters on shrimp species of economic interest.
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Pereira, Wanessa Gomes, Almeida, Ariádine Cristine de, Barros-Alves, Samara de Paiva, and Alves, Douglas Fernandes Rodrigues
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SPECIES distribution ,ENVIRONMENTAL disasters ,SHRIMPS ,COASTAL biodiversity ,DAM failures ,COASTS ,MARINE debris - Abstract
Here, we used distribution models to predict the size of the environmentally suitable area for shrimps of fishing interest that were impacted by the tailing plume from the collapse of the Fundão Dam, one of the largest ecological disasters ever to occur in Brazil. Species distribution models (SDMs) were generated for nine species of penaeid shrimp that occurred in the impacted region. Average temperature showed the highest percentage of contribution for SDMs. The environmental suitability of penaeids varied significantly in relation to the distance to the coast and mouth river. The area of environmental suitability of shrimps impacted by tailings plumes ranged from 27 to 47 %. Notably, three protected areas displayed suitable conditions, before the disaster, for until eight species. The results obtained by the SDMs approach provide crucial information for conservation and restoration efforts of coastal biodiversity in an impacted region with limited prior knowledge about biodiversity distribution. • The distance from the coast and the river mouth affects the suitability of shrimps. • The tailings plume impacted extensive areas targeted by fishing activities. • Protected areas have environmental suitability for different sets of species. • SDMs provide insights when there is limited knowledge about species distribution. [ABSTRACT FROM AUTHOR]
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- 2024
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5. Influences of voltage allocation and magnetic field introduced position on the dust removal performance of multi-electric field ESP.
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Zhang, Pengju, Zhang, Jianping, Wang, Jiaqi, Zhao, Dawen, Wang, Liquan, and Zha, Zhenting
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DUST removal , *MAGNETIC fields , *MAGNETIC field effects , *PARTICULATE matter , *VOLTAGE , *ENERGY consumption , *FLUE gases - Abstract
• The dust-removal mechanism in a multi-electric field ESP is explored. • A multi-electric field ESP model with multi-field coupling effect is built. • The optimal voltage allocation reduces the energy consumption. • The PM2.5 collection efficiency with or without magnetic field is explored. • The best magnetic field introduction position promotes the dust removal performance. Improving the removal efficiency of PM2.5 particles is significant for the limitation of particle emissions from coal-fired power plants. This work reports a multiple electric field electrostatic precipitator (ESP) enhanced by magnetic confinement effect to efficiently remove PM2.5 particle from flue gas. Firstly, the electromagnetic dust removal mechanism of PM2.5 capture in multi-electric field ESPs is revealed, and the theoretical and numerical models of the multifield coupling under the effect of magnetic field are established. Secondly, the potential distribution law under different working voltages and the dust removal performance for PM2.5 are analyzed, and the magnetic field effect under the optimal voltage allocation is numerically simulated. Finally, the best magnetic field introduction position under the optimal voltage allocation is investigated. The numerical results show that the optimal voltage allocation and the best magnetic field position are determined to achieve the full effect of magnetic field to improve the PM2.5 dust removal efficiency in the multi-electric field ESP under the premise of ensuring the decrease of voltage load. The relevant results can provide ideas and references for greatly reducing PM2.5 emissions and voltage power consumption in thermal power plants. [ABSTRACT FROM AUTHOR]
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- 2024
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6. Effect of nonuniform solar radiation on the performance of solar thermoelectric generators.
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Xuan, Zhiwei, Ge, Minghui, Zhao, Chenyang, Li, Yanzhe, Wang, Shixue, and Zhao, Yulong
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THERMOELECTRIC generators , *SOLAR radiation , *HEAT transfer , *RADIATION - Abstract
Solar radiation must be concentrated before irradiating hot sides in solar thermoelectric generators (STEGs) to increase the temperature difference between hot and cold sides and thus enhance output performance. However, concentrated solar radiation is often nonuniform. This condition affects the output performance of STEGs. Herein, a thermal–electric coupled model of STEGs was constructed to investigate the thermoelectric performance of STEGs under nonuniform solar radiation. Results demonstrate that when the concentration ratio is low, increasing nonuniformity facilitates the increase in the output power of STEGs. When the concentration ratio is 60, output power increases by a maximum of 3.05 %, whereas the average temperature difference decreases by 4.44 K. When the concentration ratio is high, STEG output power peaks under a specific nonuniformity, and some thermoelectric legs at the edges of STEGs turn into load, affecting the overall STEG output performance. When the cold-side cooling performance is poor, the solar radiation input to STEGs should be made as uniform as possible to ensure the output performance and safe operation of STEGs. The results of this study provide guidance for the design of efficient STEGs. • STEG model considering non-uniform radiation is established. • Non-uniform radiation increases efficiency by 3.05 % at concentration ratio of 60. • There is a non-uniform radiation distribution to maximize efficiency. • Heat transfer at the cold side should be enhanced under non-uniform radiation. [ABSTRACT FROM AUTHOR]
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- 2024
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7. Projecting the potential distribution of ticks in China under climate and land use change.
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Yang, Xin, Gao, Zheng, Wang, Luqi, Xiao, Lingjun, Dong, Na, Wu, Hongjuan, and Li, Sen
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TICKS , *LAND use , *TICK-borne encephalitis , *TICK-borne diseases , *ANIMAL diseases , *LYME disease - Abstract
[Display omitted] • Impacts of climate and land use change on the distribution of ticks were explored. • A model of different ticks showed diverse sensitivities to environmental factors. • The future distribution probability decreased under the scenario SSP5-RCP8.5. • The future potential distribution of ticks shifted further north in China. Ticks are known as vectors of several pathogens causing various human and animal diseases including Lyme borreliosis, tick-borne encephalitis, and Crimean-Congo hemorrhagic fever. While China is known to have more than 100 tick species well distributed over the country, our knowledge on the likely distribution of ticks in the future remains very limited, which hinders the prevention and control of the risk of tick-borne diseases. In this study, we selected four representative tick species which have different regional distribution foci in mainland China. i.e., Dermacentor marginatus , Dermacentor silvarum , Haemaphysalis longicornis and Ixodes granulatus. We used the MaxEnt model to identify the key environmental factors of tick occurrence and map their potential distributions in 2050 under four combined climate and socioeconomic scenarios (i.e., SSP1-RCP2.6, SSP2-RCP4.5, SSP3-RCP7.0 and SSP5-RCP8.5). We found that the extent of the urban fabric, cropland and forest, temperature annual range and precipitation of the driest month were the main determinants of the potential distributions of the four tick species. Under the combined scenarios, with climate warming, the potential distributions of ticks shifted to further north in China. Due to a decrease in the extent of forest, the distribution probability of ticks declined in central and southern China. In contrast with previous findings on an estimated amplification of tick distribution probability under the extreme emission scenario (RCP8.5), our studies projected an overall reduction in the distribution probability under RCP8.5, owing to an expected effect of land use. Our results could provide new data to help identify the emerging risk areas, with amplifying suitability for tick occurrence, for the prevention and control of tick-borne zoonoses in mainland China. Future directions are suggested towards improved quantity and quality of the tick occurrence database, comprehensiveness of factors and integration of different modelling approaches, and capability to model pathogen spillover at the human-tick interface. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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8. The effect of El Niño and La Niña episodes on the existing niche and potential distribution of vector and host species of American Cutaneous Leishmaniasis.
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Ávila-Jiménez, Julián, Gutiérrez, Juan David, and Altamiranda-Saavedra, Mariano
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CUTANEOUS leishmaniasis , *MEDICAL climatology , *HOST-parasite relationships , *ZOONOSES , *INSECTICIDE resistance ,EL Nino ,LA Nina - Abstract
• The study can guide integrated vector management programs for leishmaniasis, targeting surveillance and control measures more effectively. • By understanding how potential distributions change with climatic anomalies, health agencies can anticipate outbreaks and adjust strategies accordingly. • The research provides valuable insights into the complex dynamics of vector-borne disease transmission under varying climatic conditions. • It highlights the need for comprehensive approaches that consider both host and vector species and their interactions in disease management. • The study's findings can inform policy decisions and resource allocation for disease prevention and control. Leishmaniasis is a zoonotic disease transmitted to humans by a protozoan parasite through sandfly vectors and multiple vertebrate hosts. The Pan American Health Organization reported a declining trend in cases, with Brazil, Colombia, Peru, Nicaragua, and Bolivia having the most cases in 2020. There are still knowledge gaps in transmission and the parasite-host relationship. Ecological niche modeling has been used to study host-vector relationships, disease dynamics, and the impact of climate change. Understanding these aspects can aid in early surveillance and vector control strategies. The potential distribution of five host species associated with the transmission of cutaneous leishmaniasis (CL) was modeled. Occurrence data were collected for each host species, and environmental variables were used to build the models. Climatic data from El Niño, La Niña, and Neutral episodes were used to compare the predicted distributions. Additionally, the potential distributions of four vector species were compared to identify overlaps with host species. Niche analysis was conducted to evaluate changes in vector niches across episodes and to identify host-vector pairs based on niche overlap in geographic and environmental spaces. After spatial thinning, 467 records were obtained, and 1,190 candidate models were evaluated for each species. Results showed the distribution of occurrences in the environmental space, highlighting a high risk of extrapolation beyond the calibration areas. Movement-Oriented Parity analysis revealed distinct distribution patterns under different climate conditions, with areas of environmental similarity identified. Bradypus variegatus exhibited a broad potential distribution, while Dasypus novemcinctus and Didelphis marsupialis had more restricted ranges. Sylvilagus braziliensis covered most of the Neotropics. Our study provides valuable insights into ecological niches and geographic ranges of these species, contributing to the understanding of cutaneous leishmaniasis transmission dynamics. [ABSTRACT FROM AUTHOR]
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- 2024
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9. The predicted potential distribution of Aedes albopictus in China under the shared socioeconomic pathway (SSP)1–2.6.
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Liu, Qing, Zhang, Heng-Duan, Xing, Dan, Jia, Nan, Du, Yu-Tong, Xie, Jing-Wen, Wang, Ming, Li, Chun-Xiao, Zhao, Teng, Jiang, Yu-Ting, Dong, Yan-De, Guo, Xiao-Xia, Zhou, Xin-Yu, and Zhao, Tong-Yan
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AEDES albopictus , *CURRENT distribution , *GLOBAL warming , *MOSQUITOES , *INTERNATIONAL trade , *INTRODUCED species - Abstract
• Two models were used to predict the potential distribution of Ae. albopictus in China. • The future bioclimatic variables were under the SSP1–2.6. • The range of Ae. albopictus in China is predicted to expand westwards. Aedes albopictus (Skuse) (Diptera: Culicidae) is one of the 100 most invasive species in the world and represents a significant threat to public health. The distribution of Ae. albopictus has been expanding rapidly due to increased international trade, population movement, global warming and accelerated urbanization. Consequently, it is very important to know the potential distribution area of Ae. albopictus in advance for early warning and control of its spread and invasion. We randomly selected 282 distribution sites from 27 provincial-level administrative regions in China, and used the GARP and MaxEnt models to analyze and predict the current and future distribution areas of Ae. albopictus in China. The results showed that the current range of Ae. albopictus in China covers most provinces such as Yunnan and Guizhou Provinces, and the distribution of Ae. albopictus in border provinces such as Tibet, Gansu and Jilin Provinces tend to expand westwards. In addition, the potential distribution area of Ae. albopictus in China will continue to expand westwards due to future climate change under the SSP126 climate scenario. Furthermore, the results of environmental factor filtering showed that temperature and precipitation had a large effect on the distribution probability of Ae. albopictus. [Display omitted] [ABSTRACT FROM AUTHOR]
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- 2023
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10. Potential distribution analysis of an invasive alien species Parapediasia teterrella (Lepidoptera, Crambidae) in East Asia.
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Jie, Lulan, Yang, Jingbo, and Li, Weichun
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• This pest has potential to establish in Southeast China, South Korea and Japan. • Bio1, Bio11 and Bio19 mainly affect the geographical distribution of this pest. • The basic information for an evaluation of the establishment capacity of this species are provided. • We gives morphological diagnosis to ensure its precise identification. The bluegrass webworm moth Parapediasia teterrella (Zincken, 1821) is a notorious pest that is native to North America. However, it has invaded East Asia and has caused serious economic losses in China and Japan. The objective of this paper is to analyse the potential geographic distribution of P. teterrella in East Asia with MaxEnt, using predictor variables related to temperature and precipitation. It is suggested that this species has potential to establish in Southeast China, most areas of Jeollanam-do, eastern coastal region of South Korea, and most areas of Japan. Furthermore, we applied the Jackknife test to evaluate the significance of climatic variables in modelling the potential distribution of P. teterrella. The result indicates that annual mean temperature (Bio1), mean temperature of the coldest quarter (Bio11) and precipitation of the coldest quarter (Bio19) mainly affect its geographical distribution. A map showing the potential distribution of P. teterrella in East Asia is provided, and morphological diagnosis of the species is also given. [ABSTRACT FROM AUTHOR]
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- 2020
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11. Crystal, Hirshfeld, ADMET, drug-like and anticancer study of some newly synthesized imidazopyridine containing pyrazoline derivatives.
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Kuthyala, Sharanya, Hanumanthappa, Manjuanatha, Madan Kumar, S., Sheik, Sana, Gundibasappa Karikannar, Nagaraja, and Prabhu, Ashwini
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IMIDAZOPYRIDINES , *MONOCLINIC crystal system , *ELECTRIC potential , *CRYSTALS , *CRYSTAL structure ,POTENTIAL distribution - Abstract
To steer the selection of a potent drug, computer models have been fostered as a valid alternative to reduce pharmacokinetics related failure. The present study mainly focuses on the relationship between molecular properties and anticancerous activity of some newly synthesized aza heterocycles. Twelve new imidazo[1,2-a]pyridine incorporated pyrazoline derivatives were synthesized and were well characterized by 1HNMR, 13CNMR, LC-MS analysis. X-ray study resolved the structure of 4g, 4i and 4j as monoclinic crystal system. To quantify the electrostatic potential distribution and percentage intermolecular contacts in crystal packing, Hirshfeld surface study was performed. Moreover, virtual screening focused on ADMET and drug-like attributes to identify a promising derivative among the series. The anticancerous activity of the compounds was evaluated against A549 cell line. The study was further validated by subjecting best active compounds to induced hemolysis, which finally confirmed 4j as a potent molecule both in computational and in vitro study. Image 1 • New imidazopyridine-pyrazolines were synthesized and well characterized. • Crystal structures of 4g, 4i and 4j were well defined and analyzed their Hirhsfeld surfaces. • Virtual screening predicted ADMET property, Druglike and bioactivity scores. • Anticancerous activity against A549 was evaluated and validated by docking study. • HRBCs membrane stabilization property of most active compounds was evaluated. [ABSTRACT FROM AUTHOR]
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- 2019
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12. Data-driven approach for spatiotemporal distribution prediction of fault events in power transmission systems.
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Sun, Chenhao, Wang, Xin, and Zheng, Yihui
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POWER transmission , *ASSOCIATION rule mining , *FAULT diagnosis , *DATA distribution ,POTENTIAL distribution - Abstract
• The spatiotemporal distribution of the future fault events in power transmission systems is predicted in a longer timescale. • The rarely occurred environmental elements and fault causes are incorporated by the proposed RARM model. • The relative weights of environmental elements and fault causes are established. • Specific assessment of the prediction according to each fault cause is conducted by an extended CIM. • The accuracy of predictions is improved and the scope of real applications is enlarged. The spatiotemporal distribution of future fault events in a power transmission system assists in operational planning and maintenance scheduling. To this end, this paper proposes an environmental attributes-based framework for the spatiotemporal distribution prediction of potential fault events in the system. In this framework, the distribution of future fault events is predicted via the forecasted information of the environmental attributes rather than the electrical attributes. An extensive investigation covering all environmental attributes including the fault causes is presented, and the underlying fault-attribute relationships are explored. Notably, the rare association rule mining is employed to cope with the rare occurred elements in each environmental attribute through five new significance measurements. Next, to distinguish the diverse influence of each environmental element on the reliability of the whole system, the relative weights are developed. Also, the impact of the latent erroneous predictions of the events caused by one fault cause on the overall prediction performance is assessed via an extended definition of the component importance measurement. Ultimately, the efficiency of the modified significance measurements, the prediction performance in the two test cases, and the impact of each single fault cause are validated by an empirical study. The flexibility and the robustness of this framework in real applications are therefore demonstrated. [ABSTRACT FROM AUTHOR]
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- 2019
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13. Molecular structure, optoelectronic properties, spectroscopic (FT-IR, FT-Raman and UV–Vis), H-BDE, NBO and drug likeness investigations on 7, 8-benzocoumarin-4-acetic acid (7BAA).
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Khemalapure, Seema S., Katti, Vinay S., Hiremath, Chidanandayya S., Basanagouda, Mahantesha, Hiremath, Sudhir M., Armaković, Sanja J., and Armaković, Stevan
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MOLECULAR structure , *N-type semiconductors , *POTENTIAL energy , *REORGANIZATION energy , *RAMAN effect ,POTENTIAL distribution - Abstract
Experimental and theoretical spectroscopic studies were performed for the 7, 8-benzocoumarin-4-acetic acid (7BAA). The research work was performed in two levels. In the first level, experimental FT-IR, FT-Raman and UV–Vis spectral data were recorded. In the next level, the theoretical computations have been conducted from DFT∖B3LYP∖6-311++G (d, p) basis level. Initially theoretical geometrical parameters were obtained and compared with the related experimental parameters. The computed FT-IR and FT-Raman frequencies collected from same basis level and compared with experimental data. The important wavenumber assignments were achieved on the PED of individual vibrational mode. Theoretical (TD-DFT) and experimental UV–Vis absorption wavelengths (λ) were compared with each other. The FMO, NBO, MEP analyses were performed. In addition, molecular dynamic (MD) simulations, molecular docking and selected optoelectronic properties have been studied. Image 10487 • The complete vibrational assignments of 7BAA were performed on the basis of the potential energy distribution (PED). • Energy gap of the title molecule was 4.04 eV and it indicates that 7BAA is good chemical reactive. • In NBO analysis transition of LP (2) O25.→ π*(C24–O26) is exhibiting high stabilization energy of 44.79 kcal/mol. • ALIE surface on the other side indicated several molecular locations possibly sensitive towards the electrophilic attacks. • Reorganization energies indicate that 7BAA molecule might be better p-type than n-type semiconductor. [ABSTRACT FROM AUTHOR]
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- 2019
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14. The potential global distribution and dynamics of wheat under multiple climate change scenarios.
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Yue, Yaojie, Zhang, Puying, and Shang, Yanrui
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Accurately predicting changes in the potential distribution of crops resulting from climate change has great significance for adapting to and mitigating the impacts of climate change and ensuring food security. Based on very large datasets of wheat (Triticum aestivum L.) occurrence points and the main environmental factors that affect wheat growth, we used the Maxent model to predict the future global potential distribution and land suitability for wheat cultivation under multiple global climate change scenarios. Our results indicated that the suitability for wheat cultivation is primarily influenced by climatic factors and that the ≥0 °C accumulated temperature is especially important. The RCP4.5 scenario is more favourable for wheat cultivation, whereas the RCP8.5 scenario is the least favourable. Moreover, land suitability for wheat cultivation increased in Europe, Russia, the United States, Canada, China, and Pakistan, whereas a decreasing trend in suitability was found in Central and Eastern Africa, Australia, and South India. Overall, climate change is predicted to increase land suitability for wheat cultivation in middle- and high-latitude areas, and to decrease suitability in low latitude areas. Although the global distribution of wheat will not significantly alter with climate change, the risks to wheat cultivation may be significantly higher in the future because of high temperatures, heat waves, and droughts caused by climate change. Unlabelled Image • Representative samples are of great vital for wheat distribution prediction. • Potential wheat distribution changes slightly by the end of this century. • Climate change will benefit wheat planting in middle-high latitude. [ABSTRACT FROM AUTHOR]
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- 2019
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15. Investigation of the mechanism of domain switching in different Na0.5Bi0.5TiO3 microstructures.
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Zhu, Zhe, Li, Junpeng, Li, Shanjie, and Li, Chao
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BISMUTH , *PIEZORESPONSE force microscopy , *TITANATES , *MAGNETIC domain , *BISMUTH titanate , *MICROSTRUCTURE , *ELECTRIC potential ,POTENTIAL distribution - Abstract
Several researches have studied the physical properties of hydrothermally-synthesized low dimensional piezoelectric nanostructures. However, the obtained piezoelectric coefficient is not high and the relationship between physical properties and microstructures is still neglected. Here we report the piezoelectric and ferroelectric properties of different lead-free sodium bismuth titanate (Na 0.5 Bi 0.5 TiO 3 , NBT) microstructures synthesised with hydrothermal routes and give visualization of domain structures using piezoresponse force microscopy. The NBT nanowire exhibits better local piezoelectric response compared with NBT spherical aggregates and microcubes and other one-dimensional materials prepared by hydrothermal method and the large piezoelectric coefficient of nanowire was explained by observed regular stripe domain structures. Moreover, it is found that there are different domain configurations at the top and side of the nanowire under the external electrical fields, which don't change the regular stripe domain structure but lead to the movement of domain boundaries. By finite element modeling, it attributes to the different electric potential distributions from tip within the nanowire. [ABSTRACT FROM AUTHOR]
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- 2019
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16. Modeling discontinuous potential distributions using the finite volume method, and application to liquid metal batteries.
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Weber, Norbert, Landgraf, Steffen, Mushtaq, Kashif, Nimtz, Michael, Personnettaz, Paolo, Weier, Tom, Zhao, Ji, and Sadoway, Donald
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FINITE volume method , *LIQUID metals ,POTENTIAL distribution - Abstract
The electrical potential in a battery jumps at each electrode-electrolyte interface. We present a model for computing three-dimensional current and potential distributions, which accounts for such internal voltage jumps. Within the framework of the finite volume method we discretize the Laplace and gradient operators such that they account for internal jump boundary conditions. After implementing a simple battery model in OpenFOAM we validate it using an analytical test case, and show its capabilities by simulating the current distribution and discharge curve of a Li‖Bi liquid metal battery. [ABSTRACT FROM AUTHOR]
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- 2019
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17. The potential geographical distribution of Haloxylon across Central Asia under climate change in the 21st century.
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Li, Jiangyue, Chang, Hong, Liu, Tong, and Zhang, Chi
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CLIMATE change , *TWENTY-first century , *GENERAL circulation model , *PLANT habitats , *RADIATIVE forcing ,POTENTIAL distribution - Abstract
• Species distribution modeling was used to predict the distribution of H. persicum and H. ammodendron. • Temperature made the greatest contribution to the distribution model for Haloxylon vegetation. • The area of H. persicum will shrink, but the area of H. ammodendron will expand. • Ecological corridors should be established in central Uzbekistan and southern Kazakhstan. Members of Haloxylon are unique key species in the deserts of Central Asia (including Soviet Central Asia (SCA) and Xinjiang, China (XJ)). The region is a hotspot of global warming, and the plants' habitats are threatened by climate change. By using normal-climate data and future climate projections from 17 general circulation models (GCMs), we herein simulate the present and future potential habitats of Haloxylon persicum (H. persicum) and Haloxylon ammodendron (H. ammodendron) in Central Asia using a Maximum Entropy (MaxEnt) model that was developed based on 307 specimen records of Haloxylon vegetation. The MaxEnt model showed high accuracy, with an average training area under the curve (AUC) value of 0.93-0.95. Our analysis indicated that temperature and precipitation play equally important roles in shaping the spatial distribution of these desert shrubs. According to the model estimates, the current (based on 1961–1990 climate normals) potential habitats of H. persicum and H. ammodendron are 1.56 × 106 km2 and 1.53 × 106 km2, respectively, mostly (93.1% and 75%, respectively) distributed in SCA. Model projections based on two future climate scenarios, namely, the Representative Concentration Pathway (RCP) 4.5 and 8.5 scenarios (representing stabilized radiative forcing at 4.5 W m−2 and 8.5 W m−2 by the end of the 21st century, respectively), predicted that the potential habitat of H. persicum will increase by 44% (RCP4.5) to 62% (RCP8.5) but that the potential habitat of H. ammodendron will decrease by 22% (RCP4.5) to 34% (RCP8.5) in the late-21st century. The potential habitats of Haloxylon vegetation will gradually be lost in XJ but will expand in southwestern Kazakhstan circa 2041–2060 and 2061-2080. Therefore, it is advisable to protect the habitats of Haloxylon species in XJ (esp. southern XJ), where strong warming in the future might impose severe stress, and establish ecological corridors in central Uzbekistan and southern Kazakhstan to facilitate Haloxylon redistribution, as the geographical centroid of the Haloxylon habitats is shifting northward and westward in Central Asia. [ABSTRACT FROM AUTHOR]
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- 2019
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18. The evolving threat of Rapid 'Ōhi'a Death (ROD) to Hawai'i's native ecosystems and rare plant species.
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Fortini, Lucas B., Kaiser, Lauren R., Keith, Lisa M., Price, Jonathan, Hughes, R. Flint, Jacobi, James D., and Friday, J.B.
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ENDANGERED species ,RARE plants ,PLANT species ,ENDANGERED plants ,POTENTIAL distribution ,CLIMATE extremes - Abstract
• Ceratocystis lukuohia is responsible for widespread mortality of 'ōhi'a on Hawai'i. • We projected the potential distribution of C. lukuohia across the Hawaiian Islands. • 63% of endangered plants have >50% of their range in areas suitable for C. lukuohia. • Protecting habitat by fencing reduces incidences of C. lukuohia. • A dynamic web portal hosts updated results online at http://hawaiirodresearch.org/. Hawai'i's most widespread native tree, 'ōhi'a lehua (Metrosideros polymorpha), has been dying across large areas of Hawai'i Island mainly due to two fungal pathogens (Ceratocystis lukuohia and Ceratocystis huliohia) that cause a disease collectively known as Rapid 'Ōhi'a Death (ROD). Here we examine patterns of positive detections of C. lukuohia as it has been linked to the larger mortality events across Hawai'i Island. Our analysis compares the environmental range of C. lukuohia and its spread over time through the known climatic range and distribution of 'ōhi'a. Analyses show this fungal pathogen generally encompassed the core, but not the extremes of the climatic range of 'ōhi'a. We further modeled the potential distribution of C. lukuohia across the Hawaiian Archipelago to estimate the risk of ROD to other islands. Given the potential for C. lukuohia to alter the structure of 'ōhi'a dominated forests, we used our projected potential distribution of C. lukuohia to assess the risk of ROD to threatened and endangered plant species across Hawai'i. Many native plants are likely vulnerable to these types of large 'ōhi'a mortality events: of 234 endangered native plant species considered, 147 (62.8%) have more than half of their range within current and expanding C. lukuohia suitable areas. We also found evidence that protecting habitat by fencing out introduced feral ungulates reduces the prevalence of the disease likely by reducing physical damage caused by these animals to 'ōhi'a trees, a precondition for Ceratocystis infection. Given the ongoing spread of C. lukuohia , we developed a dynamic web portal to host our results online, where models and analyses are updated with new lab-confirmed detections to provide managers with a useful tool to help monitor and assess the risk of C. lukuohia as it continues to spread. [ABSTRACT FROM AUTHOR]
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- 2019
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19. The chlorine contents and chain lengths influence the neurobehavioral effects of commercial chlorinated paraffins on zebrafish larvae.
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Yang, Xinyue, Zhang, Bin, Gao, Yuan, Chen, Yawen, Yin, Daqiang, and Xu, Ting
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CHLORINATED paraffin , *ZEBRA danio embryos , *CHLORINE , *LARVAE , *ENVIRONMENTAL health ,POTENTIAL distribution - Abstract
• The neurotoxicity of CPs were assessed using zebrafish larvae-based behavioral tests. • The chlorine content of CPs possessed more influence than carbon chain length. • The coordination of three indicators enhanced the test's sensitivity and resolution. Increasing concern has arisen regarding ubiquitous environmental distribution and potential ecological and health risks of chlorinated paraffins (CPs), especially short chain congeners. Four commercial CP products with different carbon chain lengths and chlorine contents were employed to investigate and compare the possible neurotoxic effects on zebrafish larvae at 5 days post fertilization using behavioral tests, including locomotion, path angle, and two-fish social interaction. The high-chlorinated short-chain CP-70 product resulted in the strongest effects in all three tests, while the low-chlorinated long-chain CP-42 product was on the other end of the spectrum. The consequences of the chain length of two CP-52 products could be clearly distinguished by the tests. Although exposure to the two products both caused inhibition in the locomotion test, they resulted in different kinds of effects in the path angle and interaction tests. Our results suggested, as evidenced by the sensitivity and resolution of the behavioral tests, that the influence of the chain length and chlorine content of CPs could be well characterized and that chlorine content consistently showed a more significant impact than chain length. The health threats of long-chain CPs could also not be overlooked when they contained relatively high chlorine contents. [ABSTRACT FROM AUTHOR]
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- 2019
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20. Characteristics of self-potential of coal samples under uniaxial compression.
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Yang, Cai, Liu, Shengdong, Liu, Jing, Yang, Haiping, and Xie, Jingyan
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COAL sampling , *BITUMINOUS coal , *SURFACE potential , *CRACK closure , *ELASTIC deformation , *MATERIAL fatigue , *FATIGUE life ,POTENTIAL distribution - Abstract
Deformation and fracture of a coal body under load may cause potential changes. Using coal samples under uniaxial compression, the coupling relationships between coal mass potential (surface potential) and stress during a complete stress–strain process were determined. Based on the potential difference of coal samples during loading rupture, the time–space evolution signatures of the electrical potential and stress of bituminous and anthracitic coal samples under load during a complete stress–strain process were dynamically depicted with high precision. Experimental results demonstrated that the parameters of self-potential and stress of these coals showed consistent variation with change of uniaxial loading pressure. During the initial stage of uniaxial compression (crack closure and elastic deformation), the self-potential difference of bituminous and anthracitic coals showed a linear increase or decrease with increasing uniaxial pressure, with average rates of change of 0.3565 mV/MPa and 1.1128 mV/MPa, respectively. With a gradual increase of uniaxial loading pressure (into the softening stage), the catastrophic points of uniaxial loading pressure corresponded to the inflection points of the self-potential change. The magnitude of the changes in the self-potentials of both bituminous and anthracitic coals was 10–100 mV before and after the last inflection points. The surface potential distribution of coal samples during uniaxial loading was well described by the self-potential profile, which indicated the degree of damage to the sample. The self-potential of a coal sample caused by deformation and fracture can therefore be used to evaluate the stress state of the coal mass. This work provides a theoretical foundation for application to a method for early prediction of coal and rock dynamic disasters. • Self-potential data collected for coals during whole process of uniaxial loading. • Characteristics of self-potential of coal under uniaxial loading were studied. • Surface potential distribution indicated the evolution of damage to sample. [ABSTRACT FROM AUTHOR]
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- 2019
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21. Using species distribution model to predict the impact of climate change on the potential distribution of Japanese whiting Sillago japonica.
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Zhang, Zhixin, Xu, Shengyong, Capinha, César, Weterings, Robbie, and Gao, Tianxiang
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SPECIES distribution , *CLIMATE change , *RECEIVER operating characteristic curves , *OCEAN temperature , *SENDAI Earthquake, Japan, 2011 ,POTENTIAL distribution - Abstract
• We developed an ensemble species distribution model for Japanese whiting Sillago japonica for the first time. • The model successfully predicted the habitat suitability of this species under current condition. • The potential distribution range of S. japonica will become shrinking and move northward under future climate scenarios. • Our results have important implications for future fisheries management strategies. Climate change is one of the most serious global environmental problems and it is of great importance to understand how species respond to climate change. Species distribution models (SDMs) have been regarded as an effective tool to examine the impacts of climate change on species' potential distribution. In this study, we developed a SDM for a marine fish, the Japanese whiting Sillago japonica by using records of its occurrence and five predictor variables (ocean depth, distance to shore, mean sea surface temperature, salinity, and currents velocity) and predicted its habitat suitability for current conditions and under scenarios of future climates. The SDM suggests that ocean depth, distance to shore, and temperature are the three most important predictor variables determining the distribution of S. japonica. Our SDM accurately predicted the current distribution of the species, with values of true skill statistics and area under the receiver operating characteristic curve above 0.95. Under future climate scenarios, the suitable habitat of S. japonica is predicted to become smaller in size and to shift northward. Differences between climate change scenarios for 2040–2050 and 2090–2100 showed that this species will lose more suitable habitat as climate change progresses over time. Future fisheries management strategies should take this range contraction and associated northward shift into account. [ABSTRACT FROM AUTHOR]
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- 2019
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22. Organic geochemistry, distribution and hydrocarbon potential of source rocks in the Paleocene, Lishui Sag, East China Sea Shelf Basin.
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Li, Yang, Zhang, Jinliang, Liu, Yang, Shen, Wenlong, Chang, Xiangchun, Sun, Zhongqiang, and Xu, Guangchen
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ORGANIC geochemistry , *ROCKS , *ARTIFICIAL neural networks , *LIQUID hydrocarbons , *NATURAL gas ,POTENTIAL distribution - Abstract
The Lishui Sag, one of the most promising hydrocarbon exploration areas in the East China Sea Shelf Basin, has had no major breakthroughs after its exploration and development. Therefore, it is crucial to carry out a comprehensive assessment of this basin to illustrate the potential and distribution of source rocks in the Lishui Sag. Based on organic petrographic examinations, Rock-Eval pyrolysis, gas chromatography (GC) and gas chromatography–mass spectrometry (GC–MS) analysis, the organic geochemical characteristics and paleoenvironment of the source rocks were investigated. The results imply that the kerogen type of the source rocks in the Lishui Sag is dominated by Type III, with a small amount of Type II kerogen. Biomarkers show that the source rocks are characterized by a mixed origin of organic matter in a transitional environment. The lower Mingyuefeng (E 1 m l), lower Lingfeng (E 1 l l) and Yueguifeng (E 1 y) Formations show higher inputs of aquatic organic matter. The base limits of the total organic carbon (TOC) values of effective source rocks were determined to be 0.9 wt % in the E 1 m Formation, 1.0 wt % in the E 1 l Formation and 0.7 wt % in the E 1 y Formation. Based on an artificial neural network (ANN) model and the Δ log R method, the distribution of effective source rocks in the Lishui Sag was illustrated. Source rocks in the E 1 m l and Lingfeng (E 1 l) Formations can be expected to generate mixed liquid hydrocarbons, while samples from E 1 y Formation are oil prone source rocks with normal oil and light oil potentials. Additionally, the post mature source rocks of the E 1 y Formation may be the origin of natural gas. Upon full consideration of the potential and distribution of source rocks, the North part of the Lingfeng Uplift is the most favorable exploration zone. • A comprehensive assessment of source rocks in Lishui Sag is provided. • The base limits of the TOC values of effective source rocks are determined. • The source rocks in the Lishui Sag are characterized by a mixed origin of organic matter in a transitional environment. • The North of the Lingfeng Uplift is the most favorable exploration zone. [ABSTRACT FROM AUTHOR]
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- 2019
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23. Electrostatic potential and non-covalent interactions analysis for the design of selective 5-HT7 ligands.
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Rzęsikowska, Katarzyna, Krawczuk, Anna, and Kalinowska-Tłuścik, Justyna
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ELECTRIC potential , *ELECTRON density , *ELECTRON distribution , *LIGAND analysis , *CENTRAL nervous system ,POTENTIAL distribution - Abstract
Despite the significant improvement of methodology in the field of the in silico drug discovery, the search for selective drugs is still far from trivial. This is especially relevant in the case of designing new medicaments for treatment of central nervous system disorders. In this work, we present a new approach based on the molecular docking and the following electronic properties analysis of ligands' binding poses (electrostatic potential distribution analysis and quantitative topological analysis of the electron density distribution). The proposed protocol significantly increases the success rate of the selective 5-HT 7 R ligands against 5-HT 1A R selection from the prepared databases (the rise from 33.3% to 77.8% and from 22.7% to 62.5% for training and testing sets, respectively). The presented approach can be applied as a supportive method in the virtual screening of ligands databases. Image 1 • Selective medicine design is still a problem in the computer-aided drug discovery methods. • A method based on electrostatic potential analysis and topological analysis of the electron density distribution is proposed. • This protocol increases significantly success rate of selective ligands of 5-HT 7 R determination over 5-HT 1A R. [ABSTRACT FROM AUTHOR]
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- 2019
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24. The future of European onshore wind energy potential: Detailed distribution and simulation of advanced turbine designs.
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Ryberg, David Severin, Caglayan, Dilara Gulcin, Schmitt, Sabrina, Linßen, Jochen, Stolten, Detlef, and Robinius, Martin
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WIND power , *TURBINE design & construction , *POTENTIAL energy , *TIDAL currents , *ENERGY futures ,POTENTIAL distribution - Abstract
Considering the need to reduce greenhouse gas emissions, onshore wind energy is certain to play a major role in future energy systems. This topic has received significant attention from the research community, producing many estimations of Europe's onshore wind potential for capacity and generation. Despite this focus, previous estimates appear to have underpredicted both the amount of available future wind capacity as well as its performance. Foremost in this regard is the common use of contemporary, or at least near-future, turbine designs which are not fitting for a far-future context. In response to this, an improved, transparent, and fully reproducible work flow is presented here, and applied to determine a future-oriented onshore wind energy potential for Europe. Within a scenario of turbine cost and design in 2050, 13.4 TW of capacity is found to be available, allowing for 34.3 PWh of average generation per year. By sorting the explicitly-placed potential installation locations by their expected generation cost, national relationships between cost and performance versus installed capacity are found, and it is also seen that all countries possess some potential for onshore wind energy generation below 4 ct € kWh - 1. Furthermore, it is unlikely for these costs to exceed 6 ct € kWh - 1 in any future capacity scenario. • Determination of onshore wind energy potential in Europe for 2050. • Land eligibility, explicit futuristic turbine placement, and 37 simulation years. • Full potential at 13.4 TW and 34.3 PWh/a, with expected costs at or below 6 ct/kWh. • All European countries possess at least some potential below 4 ct/kWh. • Usage of futuristic turbine designs for future energy system designs is crucial. [ABSTRACT FROM AUTHOR]
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- 2019
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25. On the use of scanning Kelvin probe for assessing in situ the delamination of adhesively bonded joints.
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Andreon, B., Guenther, B.L., Cavalcanti, W.L., Colombi Ciacchi, L., and Plagemann, P.
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BOROSILICATES , *ION transport (Biology) , *ADHESIVES , *ADHESIVE joints , *POLYMERS ,POTENTIAL distribution - Abstract
• Scanning Kelvin Probe (SKP) measurements were performed through a borosilicate glass. • The potential distribution at the polymer/metal interface was measured in a real adhesive joint. • The delamination rate in the closed joint geometry was hundred times slower than in the open joint. • The delamination is limited by the ingress and availability of oxygen at the delamination front for the adhesive joint. In this paper we report on the delamination of a real closed adhesive joint geometry investigated by means of Scanning Kelvin Probe (SKP). The potential distribution at the metal/polymer interface was measured through a thin layer of glass. Quantitative measurements of the delamination kinetics were performed, accompanied by XPS inspection of the fracture surfaces. The delamination rate was found to be hundred times slower than in an open joint geometry. Furthermore, the delamination-limiting step for the open joint is the transport of cations, whereas for the closed joint is limited by the ingress of oxygen along the interphase. [ABSTRACT FROM AUTHOR]
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- 2019
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26. Isolated vs. Interconnected Wind Turbine Grounding Systems: Effect on the Harmonic Grounding Impedance, Ground Potential Rise and Step Voltage.
- Author
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Sunjerga, Antonio, Li, Quanxin, Poljak, Dragan, Rubinstein, Marcos, and Rachidi, Farhad
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- *
WIND turbines , *ELECTRIC potential , *ELECTRICAL resistivity , *WIND energy conversion systems ,POTENTIAL distribution - Abstract
• The work presents a study of the transient response wind turbine (WT) grounding system. • Simulations are carried out with full wave approach. • We analyze interconnected WT. • Frequency dependence of soil parameters is taken in account. Wind turbines are very vulnerable to lightning strikes due to their height, sharp edges and remote locations often with high soil resistivity. In this paper we present numerical simulations of the impedance of a typical wind turbine grounding geometry. We analyze the influence of interconnecting grounding systems of different wind turbines. IEC TR61400-24 suggests interconnection of grounding electrodes of wind turbines through horizontal electrodes (in the form of insulated or bare conductors) to achieve low steady-state grounding resistance. The analysis takes into account the frequency dependence of the soil electrical parameters. We show that the low frequency grounding impedance can be reduced by a factor of two or more as a result of interconnecting grounding systems. However, the reduction is significantly lower at higher frequencies because of the interconnection wire's inductance. We analyze the spatial distribution of the ground potential rise and step voltage in response to typical first and subsequent lightning return stroke current waveforms. It is shown that both, ground potential rise and step voltage can be significant along the wire, especially for high resistivity soil, and placing sensitive equipment near the interconnecting wire should be either avoided, or insulated wire should be used. [ABSTRACT FROM AUTHOR]
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- 2019
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27. Molecular dynamics simulation study on the mechanisms of liquid-phase permeation in nanopores.
- Author
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Yoshioka, Tomohisa, Kunimori, Rina, Hisaoka, Ikumi, Nagasawa, Hiroki, Kanezashi, Masakoto, and Tsuru, Toshinori
- Subjects
- *
MOLECULAR dynamics , *VISCOSITY , *VISCOUS flow , *NAVIER-Stokes equations , *LIQUID argon ,POTENTIAL distribution - Abstract
Graphical abstract Highlights • Liquid permeability through a nanopore was calculated via molecular dynamics. • The permeability was affected by the interaction between molecules and pore wall. • A new viscous flow model in nano-scale pore was proposed. Abstract Liquid-phase permeation was simulated in nano-scale pores via non-equilibrium molecular dynamics (NEMD). Two virtual cristobalite membranes were prepared with pore diameters of 1.7 and 2.4 nm. NEMD simulation system was employed as an ideal experimental system to calculate the affinity between liquid argon molecules and membrane materials during permeation. When argon-membrane interactions decreased, permeation flux increased. With a smaller interaction the permeation flux exceeded the value posited by the Hagen-Poiseuille theorem, while a lower-than-expected level of permeation flux was observed when the interactions with the pore surface became greater. We focused on the viscosity change of liquid in a nano-scale pore due to attractive or repulsive interactions with the pore surface, and a mathematical model for describing the liquid permeation flux in a nanopore was proposed by solving the Navier-Stokes equation by considering the viscosity distribution of a liquid confined in a pore. The local viscosity of a liquid confined in a pore was calculated from the total potential distribution in the pore based on the Andrade equation. The predicted level of permeation flux, the velocity profiles of different pore sizes, and the interactions of the pore models all showed good agreement with the NEMD simulation results. [ABSTRACT FROM AUTHOR]
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- 2019
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28. Multi-bit graphene-based bias-encoded metasurfaces for real-time terahertz wavefront shaping: From controllable orbital angular momentum generation toward arbitrary beam tailoring.
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Rouhi, Kasra, Rajabalipanah, Hamid, and Abdolali, Ali
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ANGULAR momentum (Mechanics) , *VECTOR beams , *DEGREES of freedom , *CHEMICAL potential , *MATHEMATICAL convolutions ,POTENTIAL distribution - Abstract
In this paper, for the first time, a new generation of multi-bit graphene-based bias-encoded metasurfaces (MGBMs) is proposed for real-time reflected wavefront manipulation at terahertz (THz) frequencies. The architecture of the designed MGBM is composed of several meta-atoms whose operational status can be independently switched between eight digital states of "000" – "111" in a real-time manner. By mere changing the distribution of chemical potentials through an external electronic source, the occupying meta-atoms can be dynamically combined in different gradient, spiral-like, and spiral-parabola-like coding sequences. Different from earlier works, the proposed MGBM can be re-programmed for accomplishing multiple outlandish missions from generation of vortex wavefronts carrying a controllable amount of orbital angular momentum (OAM) toward emitting multiple arbitrarily-oriented pencil beams at the same time. By exploiting the addition theorem and convolutional principle, multi-type functionalities, such as multiple pencil beams, multiple vortex beams with different topological charges, and multiple pencil−vortex beams are simultaneously realized. The full control of reflected wavefronts is corroborated with numerical simulations and theoretical predictions. By offering new attractive degrees of freedom to EM waves, various future directions are expected for the proposed versatile MGBM such as controllable displays, modern information systems, moving target detection, etc. Image 1 [ABSTRACT FROM AUTHOR]
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- 2019
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29. A DFT approach for theoretical and experimental study of structure, electronic, Hirshfeld surface and spectroscopic properties of 12-(4-bromophenyl)-2-(prop-2-ynyloxy)-9,10-dihydro-8H-benzo[a]xanthen-11(12H)-on single crystal.
- Author
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Singh, Harjinder
- Subjects
- *
SINGLE crystals , *SURFACE properties , *MOLECULAR orbitals , *REACTIVITY (Chemistry) , *VIBRATIONAL spectra ,POTENTIAL distribution - Abstract
• NLO material 12-(4-bromophenyl)-2-(prop-2-ynyloxy)-9,10-dihydro-8 H -benzo[ a ]xanthen-11(12 H)-on is synthesized. • Crystal structure is investigated. • Non-covalent interactions are analyzed using Hirshfeld surface and RDG method. • Physical and spectroscopic properties are investigated by DFT method. • Good correlation between theoretical and experimental results is obtained. Xanthene-propargyl derivative was synthesized by multicomponent reaction and was characterized by SCXRD analysis. Structure was optimized to ground state using DFT calculations at the B3LYP/6-311++G(d, p) level of theory in gas phase and in solvent. NBO analysis was performed at same level of theory. The vibrational spectrum was obtained theoretically by DFT calculations; vibrational assignments were made to different vibrational modes using potential energy distribution (PED) method. The non-covalent interactions present in molecule were investigated with Hirshfeld surface and fingerprint plots analysis, shape index, and curvedness using SCXRD data while theoretically these interactions were investigated using reduced density gradient (RDG) method. MEP surface was also analyzed and chemical reactivity descriptors were calculated theoretically. FMO and TDOS analysis was performed to study energy and distribution of molecular orbitals. NLO analysis was performed to determine its ability to act as potential NLO material. The high value of molar refractivity was also calculated theoretically. [ABSTRACT FROM AUTHOR]
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- 2019
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30. Spatial distribution of the theoretical potential of waste heat from sewage: A statistical approach.
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Pelda, Johannes and Holler, Stefan
- Subjects
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WASTE heat , *SEWAGE , *SEWAGE disposal plants , *HYDRAULICS , *CITIES & towns ,POTENTIAL distribution - Abstract
This paper statistically validates a novel methodology that quantifies, qualifies and spatially allocates the waste heat potential of sewage systems on an urban district level, in all cases in which real data from the sewage system does not exist or is not publicly available. The methodology is based on open data and open source technology and can be adapted to various types of cities. The results, from the application of the methodology for an example city, show that the methodology robustly calculated the paths and waste water volumetric flow from waste water sources to the waste water treatment plant. The modelled system maps the sewage system accurately within areas that have a population density close to the average. Despite small inaccuracies in the overall mapping, the methodology is able to present a good estimation of spatially distributed waste heat from water flows of the sewage system in the example city. [ABSTRACT FROM AUTHOR]
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- 2019
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31. The isotonic regression approach for an instrumental variable estimation of the potential outcome distributions for compliers.
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Choi, Byeong Yeob and Lee, Jae Won
- Subjects
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ISOTONIC regression , *CUMULATIVE distribution function , *QUANTILE regression , *LEAST squares , *INSTRUMENTAL variables (Statistics) ,POTENTIAL distribution - Abstract
This paper discusses an instrumental variable estimation of the potential outcome distributions for compliers. The existing nonparametric estimators have a limitation in that they give non-proper cumulative distribution functions that violate the non-decreasing property. Using the least squares representation of the standard nonparametric estimators, a simple isotonic regression approach has been developed. A nonparametric bootstrap method is proposed as an appropriate method used to estimate the variances of the isotonic regression estimators. A simulation study demonstrates that the isotonic regression estimators provide more proper and efficient cumulative distribution functions, with much smaller standard errors than those of the standard nonparametric estimators when the proportion of compliers is small. The methods are illustrated with a study to estimate the distributional causal effect of a veteran status on future earnings. [ABSTRACT FROM AUTHOR]
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- 2019
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32. Heterogeneous damage in Li-ion batteries: Experimental analysis and theoretical modeling.
- Author
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Xu, Rong, Yang, Yang, Yin, Fei, Liu, Pengfei, Cloetens, Peter, Liu, Yijin, Lin, Feng, and Zhao, Kejie
- Subjects
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LITHIUM-ion batteries , *MECHANICAL failures , *ELECTRON transport , *CONDUCTION electrons , *CHARGE transfer ,POTENTIAL distribution - Abstract
We assess the heterogeneous electrochemistry and mechanics in a composite electrode of commercial batteries using synchrotron X-ray tomography analysis and microstructure-resolved computational modeling. We visualize the morphological defects at multi-scales ranging from the macroscopic composite, particle ensembles, to individual single particles. Particle fracture and interfacial debonding are identified in a large set of tomographic data of active particles. Mechanical failure in the regime near the separator is more severe than toward the current collector. The active particles close to the separator experience deeper charge and discharge over cycles and thus are more mechanically loaded. The difference in the Li activity originates from the polarization of the electrolyte potential and the non-uniform distribution of the activation energy for the charge transfer reaction. We model the kinetics of intergranular fracture and interfacial degradation to confirm that the various Li activities are the major cause of the heterogeneous damage. The interfacial failure may reconstruct the conductive network and redistribute the electrochemical activities that render a dynamic nature of electrochemistry and mechanics evolving over time in the composite electrode. We further quantify the influence of the mechanical damage on the metrics of battery performance. We simulate the electrochemical impedance profile to build a relationship between the interfacial debonding and the impedance of electron transport and surface charge transfer. The mechanical failure disrupts the conduction path of electrons and results in significant polarization and capacity loss in batteries. [ABSTRACT FROM AUTHOR]
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- 2019
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33. Bayesian hidden Markov models for dependent large-scale multiple testing.
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Wang, Xia, Shojaie, Ali, and Zou, Jian
- Subjects
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FALSE positive error , *HIDDEN Markov models , *FALSE discovery rate , *MARKOV processes ,POTENTIAL distribution - Abstract
Abstract An optimal and flexible multiple hypotheses testing procedure is constructed for dependent data based on Bayesian techniques, aiming at handling two challenges, namely dependence structure and non-null distribution specification. Ignoring dependence among hypotheses tests may lead to loss of efficiency and bias in decision. Misspecification in the non-null distribution, on the other hand, can result in both false positive and false negative errors. Hidden Markov models are used to accommodate the dependence structure among the tests. Dirichlet mixture process prior is applied on the non-null distribution to overcome the potential pitfalls in distribution misspecification. The testing algorithm based on Bayesian techniques optimizes the false negative rate (FNR) while controlling the false discovery rate (FDR). The procedure is applied to pointwise and clusterwise analysis. Its performance is compared with existing approaches using both simulated and real data examples. [ABSTRACT FROM AUTHOR]
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- 2019
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34. Modeling the climate suitability of tea [Camellia sinensis(L.) O. Kuntze] in Sri Lanka in response to current and future climate change scenarios.
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Jayasinghe, Sadeeka Layomi and Kumar, Lalit
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CLIMATE change , *TEA , *ATMOSPHERIC models , *TEA growing ,POTENTIAL distribution - Abstract
• No previous studies have been conducted in Sri Lanka to assess the climate suitability for tea. • The comparison of the current and future distributions of suitable tea growing areas revealed a decline of approximately 10.5%, 17% and 8% in the total area for "optimal," "medium," and "marginal" suitability respectively. • Climate would have a negative effect on the suitability habitats of tea in Sri Lanka by 2050 and 2070 under MIROC5 and CCSM4. • Precipitation seasonality would be the most influential climatic predictor for tea in future. Knowledge of potential distributions and habitat preferences of tea (Camellia sinensis) under current and future climate conditions are vital for policy makers and stakeholders to develop suitable adaptation measures to mitigate against any detrimental effects of climate change. Without broad awareness of climate suitability and potential changes in distributions of tea growing areas, efforts of expanding the productivity of tea would remain ineffective. This study aimed to model the climate suitability of tea in Sri Lanka in response to the current and future climate change scenarios using the correlative habitat suitability model MaxEnt. Three representative concentration pathways were used under MIROC5 and CCSM4 global climate models for the year 2050 and 2070. The MaxEnt model projected current habitat suitability for tea based on existing datasets with a mean AUC of 0.92. The TSS value with a mean 0.847 ± 0.007 signifies high accuracy of predicting suitability habitats while the maximum kappa value (k) of the current and future models was around 0.454, indicating the overall performance of the model was good. In relation to the current time, areas of 6090 km2 (9.3%), 5769 km2(8.8%), and 5086 km2 were projected as potential areas of having optimal, medium, and marginal climate suitability for tea, respectively. Results show that most of the optimal and medium suitability areas in the low elevation areas would be lost to a greater extent in comparison to the high elevation areas for all tested RCPs by 2050 and 2070 under both GCMs of MIROC5 and CCSM4. The comparison of the current and future distributions of suitable tea growing areas revealed a decline of approximately 10.5%, 17% and 8% in total 'optimal', 'medium', and 'marginal' suitability areas respectively, implying that climate would have a negative effect on the habitat suitability of tea in Sri Lanka by 2050 and 2070. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
35. Heterocoagulation between coal and quartz particles studied by the mineral heterocoagulation quantifying system.
- Author
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Hu, Pengfei, Liang, Long, Li, Biao, and Xia, Wencheng
- Subjects
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DLVO theory , *ZETA potential , *QUARTZ , *COAL , *PARTICLES ,POTENTIAL distribution - Abstract
• The Mineral Heterocoagulation Quantifying System was developed. • The heterocoagulation rate complied with the classical first-order model. • Heterocoagulation results were verified by zeta potential distribution and the DLVO theory. Heterocoagulation between mineral particles, which is also called slime coating, is an intractable problem that deteriorates the separation efficiency in mineral flotation. To date, although diverse methods of characterizing mineral heterocoagulation are available, there is short of quantitative characterization. In the present work, a novel method named Mineral Heterocoagulation Quantifying System was developed to quantitatively characterize heterocoagulation. The heterocoagulation between coal and quartz particles was measured at different pH values and sodium hexametaphosphate (SHMP) concentrations. With the heterocoagulation degree given by the Mineral Heterocoagulation Quantifying System at different time, the heterocoagulation kinetics was analyzed for the first time. It was found that the heterocoagulation rate in the present work can be fitted to a classical first-order model. The zeta potential distribution measurements were also conducted to characterize heterocoagulation and the results were consistent with that given by the Mineral Heterocoagulation Quantifying System. The inter-particle force calculation based on the Deyaguin-Landau-Verwey-Overbeek (DLVO) theory was conducted to validate the heterocoagulation results. [ABSTRACT FROM AUTHOR]
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- 2019
- Full Text
- View/download PDF
36. Pickering emulsions stabilized with cashew gum nanoparticles as indomethacin carrier.
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Lima Cardial, Mayrla R., Paula, Haroldo C.B., da Silva, Rudson Brendon Cordeiro, da Silva Barros, João Felipe, Richter, Ana Rosa, Sombra, Fernanda M., and de Paula, Regina C.M.
- Subjects
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EMULSIONS , *CASHEW tree , *NUCLEAR spectroscopy , *ZETA potential , *IONIC strength ,POTENTIAL distribution - Abstract
Polysaccharide nanoparticles with potential to stabilize Pickering emulsions have been recently object of many research. Acetylated cashew gum with different degrees of substitution has been used in this work, in the pursuit of obtaining stable Pickering emulsions. Acetylated cashew gum was characterized by infrared and nuclear resonance spectroscopy. Effects of cashew gum derivative acetyl content, droplet size, ionic strength, zeta potential on emulsion properties were investigated. As a proof of concept, indomethacin was encapsulated in droplets and its release profile determined. Data obtained revealed droplet sizes in the range 269–312 nm, with unimodal size distribution and zeta potential values from −46 Mv to −48 Mv. Encapsulation efficiencies were in the range 26–52%, a steady release profile reached in 3 h, releasing maximal 75% IND. [ABSTRACT FROM AUTHOR]
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- 2019
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37. Two dimensional Green's function solution of threshold for junction less field effect transistors at low drain voltage.
- Author
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Hosseini, Seyed Akram, Eskandarian, Abdollah, and Ghadimi, Abbas
- Subjects
- *
GREEN'S functions , *FIELD-effect transistors , *THRESHOLD voltage , *LOW voltage systems , *TRANSISTORS ,POTENTIAL distribution - Abstract
The threshold voltage is an important device and circuit parameter of any FET structure. In this paper, closed form analytic expressions are derived which determine the dependence of the threshold voltage of DGJLFETs on device dimensions, and the drain voltage. The depletion approximation and the two dimensional Green's function are used to determine the terminal behavior of the device. The model includes the effect of the depletion in the gate-drain spacing. The threshold condition is reached when the depletion layers from the two sides cross i.e., when the channel pinches off. The widening of the depletion layer under sub-threshold condition, and the movement of the pinch-off point with the drain voltage are calculated. Finally, the shift in threshold voltage and DIBL with the gate length is determined. We can also determine the potential distribution within the device. To verify our calculations, the analytical results are compared with 2-D numerical simulations. The agreement is especially good at low drain voltages. • Simple and easy to use closed form expressions for the threshold voltage of DGJLFET • No need for calculating drain source current to establish the threshold condition • Includes the effect of the depletion layer in the gate-drain spacing • Using Green's function to solve the two dimensional problem [ABSTRACT FROM AUTHOR]
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- 2019
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38. Global surface solar radiation and photovoltaic power from Coupled Model Intercomparison Project Phase 5 climate models.
- Author
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Zou, Ling, Wang, Lunche, Li, Jiarui, Lu, Yunbo, Gong, Wei, and Niu, Ying
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- *
SOLAR radiation , *SOLAR surface , *ATMOSPHERIC models , *SOLAR energy ,POTENTIAL distribution - Abstract
In this study, historical surface solar radiation (1850–2005) and future photovoltaic power output (2006–2100) are analyzed to investigate the spatial distribution and long-term variation in global solar energy based on the Coupled Model Intercomparison Project Phase 5 (CMIP5) models and the Global Energy Balance Archive (GEBA) database. The results show that global mean surface solar radiation significantly decreased by 0.014 W m−2 year−1 in 1850–2005. According to the Model for Interdisciplinary Research on Climate (MIROC5), surface solar radiation significantly decreased by 3.42 W m−2 year−1 in 1951–1992 and increased by 4.75 W m−2 year−1 in 1993–2005. Global dimming and brightening were observed before and after the 1990s, respectively. The transition of surface solar radiation from dimming to brightening in Europe and the southeastern United States was detected in the 1980s. Stations in Northeast China, Japan, Southeast Africa, the Middle East, and the west coast of India all showed renewed decreasing trends after the 1990s. The direct and indirect effects of anthropogenic aerosols and cloudiness in different periods and regions were the main causes of the changes. To better understand the utilization of global solar energy, global potential photovoltaic power outputs were estimated in future scenarios with an empirical model. Significant increases in potential photovoltaic power are expected in East Asia, Europe, Central Africa and Central America in 2006–2100. The largest increase is expected in central China, where increases are occurring at 3 kWh m−2 year−1. Significantly decreasing potential photovoltaic power is observed in North Africa, the Middle East, Central Asia and Australia. The greatest decrease is observed in the Tibetan Plateau area (approximately −3.0 kWh m−2 year−1 in 2006–2100). With respect to the global distribution of potential photovoltaic power output, large quantities of photovoltaic power are distributed in the northern and southern parts of Africa, the Middle East, the Tibetan Plateau area, the west coasts of North and South America and most of Australia. The yearly mean sum photovoltaic power in these regions is larger than 2000 kW h m−2. Due to the long-term decreasing photovoltaic power (0.67 kWh m−2 year−1) expected worldwide in 2006–2100, effective and rational utilization of solar energy is of great importance. Annual PV power for 34 CMIP5 model mean and MIRCO5 in historical experiments, RCP4.5 and RCP8.5 scenarios. Image 1 • Global mean Surface downwelling shortwave radiation decreased during 1850–2005. • The predicted global mean potential photovoltaic power will decrease from 2006 to 2100. • High photovoltaic power is located in North Africa, Middle East, Central Asia and Australia. • Photovoltaic power in East Asia, Europe, Central Africa and America will increase in future. [ABSTRACT FROM AUTHOR]
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- 2019
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39. Simulation of fine focus time-of-flight Rutherford backscattering spectrometry using TRIM backscattering data.
- Author
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Seidl, Albert, Abo, Satoshi, and Takai, Mikio
- Subjects
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RUTHERFORD backscattering spectrometry , *VACUUM chambers , *BACKSCATTERING ,POTENTIAL distribution - Abstract
Fine-Focus single-event time-of-flight (TOF) Rutherford backscattering spectrometry (RBS) was simulated using TRIM data together with own software. Electron- and ion trajectories were computed by taking geometric features and potential distribution within the vacuum chamber into account. TOF spectra were extracted from the trajectory data. Simulation results were in good agreement with measurements. [ABSTRACT FROM AUTHOR]
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- 2019
- Full Text
- View/download PDF
40. Modelling current and future potential distributions of two desert jerboas under climate change in Iran.
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Mohammadi, S., Ebrahimi, E., Shahriari Moghadam, M., and Bosso, L.
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POTENTIAL distribution ,CLIMATE change ,DECISION making ,CURRENT distribution ,ECOLOGY - Abstract
Species distribution models (SDMs) are excellent tools to understand the factors that affect the potential distribution of several organisms at different scale. In this study, we analyzed the current potential distribution of the Blanford's Jerboa Jaculus blanfordi and the Arabian Jerboa Jaculus loftusi (Mammalia: Rodentia) in Iran and predicted the impact of climate change on their future potential distributions using two different modelling software packages: Maxent and sdm. Our results showed that precipitation was the most important variable affecting the potential distributions of J. blanfordi and J. loftusi in Iran. We also showed that the potential distributions of the two jerboas species are unlikely to be affected by climate change. All our models showed high levels of predictive performances. Thus, SDMs are a promising tool to complement data from laboratory and field studies to illuminate the biology and ecology of jerboa and inform management decisions. • Precipitation is the most important variable affecting the potential distributions of J. blanfordi and J. loftusi in Iran; • The potential distributions of J. blanfordi and J. loftusi are unlikely to be affected by climate change; • SDMs are a promising tool to complement data from laboratory/field studies to illuminate the biology and ecology of jerboas [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
41. Classification and regression with random forests as a standard method for presence-only data SDMs: A future conservation example using China tree species.
- Author
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Zhang, Lei, Huettmann, Falk, Liu, Shirong, Sun, Pengsen, Yu, Zhen, Zhang, Xudong, and Mi, Chunrong
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SPECIES distribution ,REGRESSION trees ,POTENTIAL distribution ,CLASSIFICATION ,SPECIES ,EFFECT of human beings on climate change - Abstract
The random forests (RF) algorithm is a superb learner and classifier in machine learning applications. This ensemble model is also one of the most popular species distribution model algorithms (SDMs) available to date. RF by default can produce categorical and numerical species distribution maps based on its classification tree (CT) and regression tree (RT) algorithms, respectively. Statistically, CT can also produce numerical predictions (class probability). Many real-world applications (e.g. conservation planning) employ binary presence–absence outputs that use classification thresholds to make these conversions. However, there is little available information regarding the difference in model performance between CT and RT for inference settings. Here, under an ensemble modeling framework, 52 forest tree species with presence-only data for all of China were selected for comparison of the performance of CT and RT algorithms in projecting the distribution and potential range shifts of these species under current and future climates. Five climatic variables were used to develop CT and RT models. Eight threshold-setting approaches were employed to convert numerical predictions into binary predictions. With regard to probabilistic predictions, the relative performance of CT and RT depended on the choice of the evaluation criteria. For both RT and CT, threshold-setting methods significantly altered the determination of thresholds, model performance, and subsequently projections of species range shifts under climate change. The four threshold selection methods (MaxKappa, MaxOA, MaxTSS, and MinROCdist) based on the composite model accuracy measures most often achieved significantly higher model performance than CT default threshold method and other threshold methods. They consistently projected that species' geographical ranges changed in response to climate change with the same direction and magnitude. We argue for choosing RT rather than CT as the SDM if model discrimination capacity (the ability to differentiate between occurrences of presence and absence) is viewed as more important than model reliability (the agreement between predicted relative indexes of occurrence and observed proportions of occurrence), and vice versa. In line with gradient theory, we can recommend the use of numerical predictions for species distribution modeling since they help to convey more information than binary predictions. Binary conversion of model outputs should only be carried out when it is clearly justified by the application's objective. The four aforementioned threshold methods are promising objective methods for binary conversions of continuous predictions when presence-only data are available. This study proposes guidelines on how machine learning can be used for specific applied and theoretical applications in a SDM context. Unlabelled Image • CT in machine learning was compared with RT for inference from predictions. • Choice of evaluation criteria changed the relative performance of CT and RT. • Choice of threshold altered model performance and species range shift projections. • Four objective threshold methods were recommended for binary predictions. • First-time generic guidelines were proposed on how to choose RF (CT or RT) methods. [ABSTRACT FROM AUTHOR]
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- 2019
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42. One-dimensional structure of multi-component fine particle (dust) clouds under gravity.
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Totsuji, Hiroo
- Subjects
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PARTICULATE matter , *DUST , *GRAVITY , *ELECTRIC potential , *SPACE plasmas ,POTENTIAL distribution - Abstract
The structure of electrostatic potential and the distribution of fine particle (dust) clouds are analyzed in the case where we have fine particles of multiple components in plasmas under gravity. This extends the model for one-dimensional structures of fine particle cloud based on the enhanced charge neutrality in clouds to multi-species cases. Fine particles of different species are shown to form stratified clouds with simply expressed mutual separations. The results may be applied to analyze or segregate mixtures of dusts in atmospheres. • Different dusts form own clouds with well-defined spacing in plasmas under gravity. [ABSTRACT FROM AUTHOR]
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- 2019
- Full Text
- View/download PDF
43. A Kinetic Approach to Determining Drug Distribution in Complex Biphasic Systems.
- Author
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Dong, Yixuan, Hengst, Leanna, Patel, Deval, Hunt, Robert, Qu, Haiou, Choi, Stephanie, Ashraf, Muhammad, Cruz, Celia N., and Xu, Xiaoming
- Subjects
- *
EMULSIONS , *PARTITION coefficient (Chemistry) , *THERAPEUTIC equivalency in drugs , *TRIAMCINOLONE acetonide , *ORGANIC solvents , *IMPACT testing ,POTENTIAL distribution - Abstract
Pharmaceutical emulsions contain multiple components, such as micellar, aqueous, and oil phases, leading to complex drug transfer and equilibrium phenomena. These complex components present challenges for the bioequivalence assessment of the drug products. The objective of the study was to develop a method that can probe the underlying mechanism and process of drug distribution. The concept of drug partitioning into biphasic systems was used to simplify the complex transfer phenomenon. A kinetic method was developed taking into account the biphasic diffusion. Using this approach, both the rate (kinetics) and the extent (equilibrium) of distribution can be determined. For method development purpose, 3 model compounds (triamcinolone acetonide, difluprednate, and cyclosporine), with expected partition coefficient values ranging from 2 to 6, were tested using the kinetic method and the traditional shake-flask method. The values obtained by the 2 methods for all compounds correlated well (r2 = 0.825). Various organic and aqueous solvents which are commonly encountered in formulations were also tested to determine the impact of phase composition on drug distribution. The kinetic method was found to offer more flexibility in terms of solvent composition and can lead to better understanding for drug distribution and potential drug release in complex biphasic systems. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
44. Analytical solutions of the Poisson-Boltzmann equation within an interstitial electrical double layer in various geometries.
- Author
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Saboorian-Jooybari, Hadi and Chen, Zhangxin
- Subjects
- *
ANALYTICAL solutions , *ANALYTIC geometry , *ELECTROLYTE solutions , *ELECTRIC potential , *EQUATIONS ,POTENTIAL distribution - Abstract
Almost all research works conducted in the area of characterization of an electrical double layer (EDL) have been principally concerned with formation of the layer outside a charged particle, but there are cases in natural and artificial systems where the layer is generated within particles. In other words, it is basically assumed that charged particles are surrounded by an electrolyte solution; however, in reality, an aqueous phase may be bounded inside charged particles. In order to address such problems, it is essential to analytically solve the Poisson-Boltzmann (PB) equation to obtain the distribution of electric potential and concentration profiles of ions within an interior EDL. Despite that the governing PB equation remains the same, analytical solutions will be completely different from cases with an exterior EDL as boundary conditions are different. Solving the PB equation for an interstitial EDL has not been fully addressed yet except for parallel plate-like particles, whose outcomes are inconvenient-to-use due to implicit forms of solutions, involving complex integrals that are not expressible in a closed form and inclusion of parameters determined by iterative numerical techniques. This article is directed at deriving accurate analytical solutions for calculation of electric potential distribution within an interstitial EDL in various particle geometries. First, an exact analytical solution of the PB equation is obtained for slab-shaped particles containing an electrolyte solution. However, because of the inherent complexity of cylindrical and spherical operators resulting from the curvature of shells, we have to derive approximate analytical solutions in these geometries under some assumptions. To account for errors associated with such assumptions, correction factors are applied to the approximated terms. Then, the overall ranges of variation of the factors are evaluated by performing sensitivity analyses on key influential parameters and it is shown that the correction factors are independent of characteristics of a system. Eventually, the analytical solutions and corresponding numerical results are compared to prove the validity of the newly-derived formulas in all practical applications. The results from this research find implications in diverse chemical/physical/biological phenomena, technological processes, and medical and industrial applications. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
45. Spatial oak decline models to inform conservation planning in the Central-Western Iberian Peninsula.
- Author
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Hernández-Lambraño, Ricardo Enrique, de la Cruz, David Rodríguez, and Sánchez-Agudo, José Ángel
- Subjects
OAK ,THALASSEMIA ,POTENTIAL distribution ,ABIOTIC stress ,PENINSULAS ,FORESTS & forestry - Abstract
• We tested the effect of abiotic factors and human influence on the distribution of Oak Decline. • We estimated its potential geographic distribution in central-western Spain. • Oak Decline distribution was explained by land use and abiotic stress conditions. • Northern and central part of the study area had higher probabilities of Oak decline. • Forestry practices are required to prevent a possible expansion. In the Iberian Peninsula, Oak Decline (hereafter, OD) is becoming a serious and frequently occurring disease in Mediterranean oaks. Decline processes seem to involve multiple biotic and abiotic factors, which combine to reduce the vigour of oak trees often causing death. However, the exact causes of its extension are still unknown and therefore, given the ecological, economic and social relevance of these trees in Mediterranean countries it is crucial to develop tools that allow us to anticipate its occurrence and to reduce its expansion. In this sense, the present work aims to (i) unravel the relative role of environmental factors on the distribution of one of the most important phenomena that threat the biodiversity of the Iberian oaks, and (ii) to produce a spatially explicit model of OD risk, to assist conservation managers dealing with this phenomenon. To this, we have used a dataset of OD foci gathered during the period 2015–2017 by the program "Methodology for the inventory and monitoring of oak masses affected by the decline of oak in the southwest of Castilla y Leon" (this region is beginning to suffer the damages of this disease). In total, 68 locations were used to assess relationships with environmental factors (topographic conditions, abiotic stress conditions and human influence) using maximum entropy models (hereafter, MaxEnt) and variance-partitioning. OD distribution seems to be principally influenced by land-use (mainly dehesas), followed by dryer areas and areas with low slope gradients facing south or southeast. The resulting model has been used to produce a detailed OD risk map in central-western Spain. Our modelling approach may contribute to inform conservation planning and to establish the adequate management policy for Iberian oak dehesas , by helping to identify regions where the risk of OD is high. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
46. Effects and potential of water-saving irrigation for rice production in China.
- Author
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Zhuang, Yanhua, Zhang, Liang, Li, Sisi, Liu, Hongbin, Zhai, Limei, Zhou, Feng, Ye, Yushi, Ruan, Shuhe, and Wen, Weijia
- Subjects
- *
IRRIGATION water , *NONPOINT source pollution , *RICE field irrigation , *PADDY fields , *RICE yields ,POTENTIAL distribution - Abstract
Graphical abstract Highlights • About 94.19% paddy fields in China are suitable for water saving irrigation (WSI). • China has the potential to increase 5.39–6.87% rice yield by fully applying WSI. • China has the potential to save 22.06–26.41% irrigation water for paddies by WSI. • China has the potential to reduce 32.11–39.11% Nitrogen loss from paddies by WSI. Abstract Water-saving irrigation (WSI) is a promising management practice for sustainable rice production. Shallow-wet irrigation (SWI), controlled irrigation (CI), intermittent irrigation (II), and rain-gathering irrigation (RGI) are four common WSI regimes used in China. Their water saving, pollutant reducing, and yield increasing effects were analysed based on literature survey from multi-site field studies across China. An index system considering the applicability and effect of different WSI regimes was developed to identify their potential distributions across China. The potential overall effect of WSI practices at the country level was then estimated. Results showed that CI had the highest average water saving rate (WSR) of 35.12% and the highest average pollutant reducing rate (PRR) of 54.97%, followed by RGI, SWI, and II; while CI had the lowest average yield increasing rate (YIR) (0.79%), followed by II (5.40%), SWI (8.12%), and RGI (11.80%). Overall, the larger the WSR , the larger higher PRR ; but the yield increasing effect will be diminished when the WSR is increased to a certain extent due to the resulting rice water stress. About 94.19% of the total paddy area in China are suitable for WSI practices and the unsuitable ones are mainly due to soil structure deterioration and low soil fertility. SWI is the most applicable WSI regime, suitable for 90.03% of paddy fields, followed by CI and II (23.33%), and RGI (4.16%). By full implementation of appropriate WSI regimes at the country level, the total WSR , PRR , and YIR are likely to reach 22.06–26.41%, 32.11–39.11%, and 5.39–6.87%, respectively. The application of WSI practices in China has noticeable potential to alleviate water shortage and non-point source pollution while ensuring high yield. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
47. Operando studies on through-plane cell voltage losses in vanadium redox flow battery.
- Author
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Lim, Hyebin, Yi, Jung S., and Lee, Doohwan
- Subjects
- *
VANADIUM redox battery , *ELECTRIC potential , *STANDARD hydrogen electrode , *OXIDATION-reduction reaction ,POTENTIAL distribution - Abstract
Abstract Through-plane potential and overpotential distributions in a vanadium redox flow battery (VRFB) is investigated in-situ using saturated Ag/AgCl reference electrodes attached to each side of the membrane with edge-type configuration. Combined with electrochemical impedance spectroscopy (EIS), this operando approach enables detailed quantification of the voltage losses contributed from the individual VRFB cell components with the magnitudes of ohmic and charge transfer losses at practical charge-discharge conditions. It is found that the overpotentials for vanadium redox reactions on graphite felt electrodes at the positive and negative half-cells are one order magnitude larger than the voltage loss through the typical cation-exchange membrane (Nafion®117) for charging-discharging at current densities from 50 to 120 mA cm−2. Within the overall half-cell overpotentials, the ohmic voltage loss accounts for about 40%. The analysis reveals that the voltage loss by the anode charge transfer reaction is about three folds larger than that by the cathode reaction, suggesting that sluggish V2+/V3+ redox kinetics in the negative half-cell is the major factor limiting the overall VRFB cell performance. This operando methodology is effective for the in-depth analysis of VRFB performance in practical conditions as well as the development of high-performance cell components and efficient total cell design by a collective and quantitative approach. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
48. A proposal based on quantum phenomena for the ORR mechanism on nitrogen-doped carbon-based electrocatalysts.
- Author
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Legarreta-Mendoza, A., Flores-Holguín, N., and Lardizabal-Gutiérrez, D.
- Subjects
- *
OXYGEN reduction , *COMPUTATIONAL chemistry , *CRYSTAL defects , *BOND angles , *ELECTRIC potential ,POTENTIAL distribution - Abstract
Several theories have tried to explain the role of nitrogen-doped carbon-based electrocatalysts during the oxygen reduction reaction (ORR). However, there is no consensus about which of the existing theories is most accurate. In this work, we propose a hypothesis presented for the first time, which consists on the hybridization change of carbon atoms in the graphene lattice, from sp2 to sp3. As shown in several studies, carbons with sp3 hybridization can store electrons (i.e. work as capacitors), this phenomenon, along with nitrogen inversion, due to lattice defects, would allow the nitrogen atom to works as a "switch", enabling or stopping the flow of electrons, generating active sites that enhance the ORR. Computational chemistry was used to prove this hypothesis. A graphene of 92 atoms doped and undoped has been constructed using the Gauss View 5.0® program, the geometries were optimized by DFT in Gaussian 0.9® software, in order to compare changes in bond angles and lengths of the lattices, and map the electrostatic potential distribution (ESP). The results obtained in the measurement of the angles and charges around the doping nitrogen presented interesting results that can help to demonstrate part of the established hypothesis about nitrogen inversion. The study shows that it is possible that this phenomenon increases when there are a greater number of defects in the lattice. Understanding this phenomenon will help to develop and know the best synthesis conditions for doped carbon electrocatalysts. • Graphene-based Nitrogen-doped metal-free electrocatalysts. • Nitrogen inversion in graphene. • DFT study for nitrogen-doped graphene. • Quantum tunnelling. • Mechanism of the ORR for Nitrogen doped metal-free electrocatalysts. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
49. Evaluation of electrochemical performance of solid-oxide fuel cell anode with pillar-based electrolyte structures.
- Author
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Shimura, Takaaki, Nagato, Keisuke, and Shikazono, Naoki
- Subjects
- *
SOLID oxide fuel cells , *ANODES , *PERFORMANCE of fuel cells , *LATTICE Boltzmann methods , *FOCUSED ion beams , *IONIC conductivity ,POTENTIAL distribution - Abstract
Among the gas, ion, and electron diffusion processes in solid-oxide fuel cell (SOFC) electrodes, it is generally known that ionic conduction has the most impact on their electrochemical performance. Therefore, enhancement of the effective ionic conductivity of electrodes is a useful approach to reduce the overpotential. Yttria-stabilized zirconia (YSZ) pillars can be effective solutions to enhance the effective ionic conductivity of SOFC anodes. In this study, the influence of YSZ pillar structures on the electrochemical performance of SOFC anodes was evaluated by numerical simulation and experiments. First, to reveal the electrochemical reaction kinetics of anodes with pillar structures, a three-dimensional electrochemical simulation was conducted by the lattice Boltzmann method. The microstructure without pillars obtained by a focused ion beam scanning electron microscopy (FIB-SEM) measurement was used as the reference structure. Then, the original structure was replaced with YSZ phase to obtain virtual microstructures with YSZ pillars. With YSZ pillars, predicted area specific resistance became smaller than that of the reference structure, in spite of decrease in percolated TPB density. The electrochemical potential distribution of oxide ion and charge-transfer currents clearly show increase in the effective ionic conductivity. Relationships between overpotential and pillar geometries were parametrically discussed. Then, electrochemical performance of Ni-YSZ anode with the YSZ pillar structure formed by modifying the YSZ electrolyte surface was evaluated. By sputtering Ni-YSZ on pillar structures, stable electrochemical performance was obtained. Image 1 • Influence of YSZ pillar structures on Ni-YSZ anode performance was investigated. • 3D electrochemical simulations were conducted by lattice Boltzmann method. • Performance enhancement is achieved by enlarged effective ionic conductivity. • Anodes with pillar structures were fabricated by laser ablation and tested. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
50. Platinum(II) and copper(II) complexes of 7-azaindole-3-carboxaldehyde: crystal structures, IR and Raman spectra, DFT calculations and in vitro antiproliferative activity of the platinum(II) complex.
- Author
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Morzyk-Ociepa, Barbara, Szmigiel-Bakalarz, Ksenia, Nentwig, Markus, Oeckler, Oliver, Malik-Gajewska, Magdalena, Turlej, Eliza, Wietrzyk, Joanna, and Michalska, Danuta
- Subjects
- *
COPPER ions , *RAMAN spectroscopy , *CRYSTAL structure , *PLATINUM , *COPPER ,POTENTIAL distribution - Abstract
Graphical abstract Highlights • In [CuBr 2 (7AI3CAH) 2 ] n , the CuBr Br Cu double bridge system is formed. • Trans- [PtCl 2 (7AI3CAH) 2 ] is comparable to cisplatin on LoVo and MCF7 cell lines. • It is much less active than cisplatin against A549 cells. • It is 8-fold less toxic against healthy BALB/3T3 cells in comparison to cisplatin. Abstract Pt(II) and Cu(II) complexes, trans -[PtCl 2 (7AI3CAH) 2 ] and [CuBr 2 (7AI3CAH) 2 ] n , containing 7-azaindole-3-carboxaldehyde (7AI3CAH) have been synthesized and investigated by a single crystal X-ray diffraction, vibrational spectroscopy and DFT calculations. In the platinum(II) complex two pyridine nitrogen atoms of the 7AI3CAH ligands and two chloride ligands are coordinated to the central metal atom, in a square-planar trans arrangement. In the polymeric copper(II) complex the coordination geometry is a tetragonal bipyramid (4 + 2), where the in-plane ligands are two pyridine nitrogen atoms of two organic ligands and two trans -bromide ligands. The apical positions of bipyramid are occupied by the two Br ligands from the neighboring units. Thus, the CuBr Br Cu double bridge system is formed. Detailed vibrational assignments of the IR and Raman spectra of the Pt(II) and Cu(II) complexes have been made on the basis of the calculated potential energy distributions (PEDs) using B3LYP method. The in vitro antiproliferative activity of trans -[PtCl 2 (7AI3CAH) 2 ] was studied against different human cancer cell lines. The results have shown that this complex is comparably cytotoxic with cisplatin at the LoVo (colon cancer) and MCF7 (breast cancer) cells, whilst its cytotoxicity is significantly lower against the A549 cells (lung cancer) as compared to cisplatin. However, it is about 8-fold less toxic than cisplatin against a normal fibroblast cell line (BALB/3T3). A study on stability of trans -[PtCl 2 (7AI3CAH) 2 ] in DMSO solution has been performed by FT-IR (ATR) spectroscopy to predict a possible binding mode of trans- platinum(II) complex with DNA. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
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