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Structural shape optimization is one important and crucial step in the design and analysis of many engineering applications as it aims to improve structural characteristics, i.e., reducing stress concentration and structural weight, or improving the stiffness, by changing the structural boundary geometries. The goal of this paper is to present an efficient approach, which goes beyond limitations of conventional methods, by combining extended isogeometric analysis (XIGA) and chaotic particle swarm optimization algorithm for shape optimization of structures with cutouts. In this setting, mechanical response of structures with cutouts is derived by the non-uniform rational B-spline (NURBS) and enrichment techniques. The computational mesh is hence independent of the cutout geometry, irrelevant to the cutout shape during the optimization process, representing one of the key features of the present work over classical methods. The control points describing the boundary geometries are defined as design variables in this study. The design model, analysis model, and optimization model are uniformly described with the NURBS, providing easy communication among the three aforementioned models, resulting in a smooth optimized boundary. The chaotic particle swarm optimization (CPSO) algorithm is employed for conducting the optimization analysis. Apart from that, the CPSO has some advantages as it includes: (i) its structure is simple and easy to implement; (ii) without the need for the complicated sensitivity analysis as compared with the traditional gradient-based optimization methods; and (iii) effectively escaping from the local optimum. The accuracy and performance of the developed method are underlined by means of several representative 2-D shape optimization examples.

A charge compensation effect between gallium (III) ions (Ga3+), which serve as acceptors, and oxygen vacancies has previously been observed in gallium (Ga)-doped tin oxide (SnO2) films. In this study, the compensation effect was eliminated by introducing nitrogen (N) atoms into the oxygen vacancy sites that form as a result of Ga3+–tin (IV) substitution. The p-type conductivity of the resulting films was increased because of the activation of passive Ga3+ acceptors and addition of nitride ion acceptors into the host lattice. Dopant N atoms were successfully introduced into the SnO2 lattice by direct-current magnetron sputtering at the optimum substrate temperature of 400 °C in a gas mixture of argon and 50% nitrogen. The highest hole concentration achieved was 6.99 × 1019 cm−3, which is one order of magnitude higher than that of Ga-doped SnO2 films with the compensation effect, and the resistivity of this co-doped film was 6.0 × 10−2 Ω cm.

The oxidative carbonylation of alcohols to prepare corresponding dialkyl carbonates was investigated using alkali metal methylselenite [MSeO2(OCH3)] and alkali metal selenites (M2SeO3, M = Li, Na, K, Cs) as catalysts. Of various alcohols tested, methanol and 2-methoxyethanol (MEG) are found to be highly reactive, affording corresponding dialkyl carbonates in yields of more than 30%, which are significantly higher than those achieved with Cu-based catalysts under similar reaction conditions. XRD and GC-Mass analysis of the spent catalyst recovered from the M2SeO3-catalyzed reaction of methanol revealed that M2SeO3 was converted into elemental selenium and MHCO3 along with the formation of several selenium-containing by-products including malodorous dimethyldiselenide, 1,2-dimethoxydiselane, and O,Se-dimethyl carbonoselenoate. On the contrary, the oxidative carbonylation of MEG with K2SeO3 was highly selective toward the formation of bis(2-methoxyethyl) carbonate (BMEC), without producing any selenium-containing by-products. A plausible mechanism for the MSeO2(OCH3)- and M2SeO3-catalyzed oxidative carbonylation of MEG was suggested on the basis of mechanistic and experimental results.

Objectives Sperm cryopreservation has great potential for male infertility treatment as used in assisted reproduction technology (ART). There are a variety of cryopreservation methods in order to preserve sperm in a long term. Although conventional freezing and vitrification now are used widely, they have damage on sperm parameters as well as sperm DNA integrity. It is necessary to answer which method is better and appropriate for sperm cryopreservation. The aim of this study was to compare the effect of conventional freezing and vitrification regarding to motility, vitality and morphology of sperm found in washed and unwashed samples. Study design One hundred and five human fresh semen samples were divided into washed and unwashed halves using density-gradient centrifugation. Each group then was split into two aliquots: one cryopreserved by conventional freezing and the other by vitrification, using SpermFreeze Solution™ (Vitrolife, Vastra Frolunda, Sweden) containing glycerol as a cryoprotectant. The sperm parameters were analyzed and compared between six groups: washed fresh (FW), unwashed fresh (FU), washed conventional freezing (CfW), unwashed conventional freezing (CfU), washed vitrification (VitW) and unwashed vitrification (VitU) samples. Results Sperm progressive motility, vitality and normal morphology significantly decreased, together with an appreciable increase in sperm head, midpiece and tail defects when comparing to the fresh sperm parameters after thawing in all groups. In conventional freezing method groups, progressive motility and vitality were substantially higher than that in vitrification method groups. However, vitrification gave better results in normal morphology rates. Additionally, sperm head, midpiece and tail defects were significant lower in two vitrification groups in comparison with conventional freezing groups. Interestingly, washed groups had better sperm parameters than unwashed groups so that washing process before frozen seemed to improve sperm parameters. Conclusion Conventional freezing method resulted in better motility, viability in both washed/unwashed groups. On the contrary, spermatozoa undergoing vitrification were healthier regarding morphology with less defects than conventional freezing. Sperm washing before frozen was a beneficial preparation to sperm cryopreservation.

The paper is mainly focused on analysis characteristics of lobe pump with three different tooth profiles: Circular, Epi-cycloidal and Circular–Involute–Circular (CIC) rotor profiles. Based on the geometric analysis and mathematical model, the CIC rotor profile combined Circular–Involute–Circular is generated. In this paper, the CFD techniques are used to estimate the effects of tooth profile and lobe number to the pump performance. The simulation results obtained from FLUENT software illustrated that the rotor profile effects remarkably to the pump performance. The outlet pressure of CIC rotor profile is higher than that of the circular and epi-cycloidal rotor profiles. The numerical outcomes also showed that higher rotor’s speed is resulted in higher outlet pressure. Besides, the lobe number of rotor has effect slightly to the pump performance.

International audience

3D printed objects are usually not completely filled to reduce weight, printing time and costs. Instead, infill structures are used. These infill structures have a major influence on the strength of 3D prints. To non-destructively investigate such infill structures, our approach is the use of terahertz time-domain spectroscopy. This paper studies possible evaluation parameters for imaging an exemplary infill structure by using both transmission and reflection measurements. Thus, a non-destructive visualization of 3D print infill structures is enabled.

We introduce a novel top-down end-to-end formulation of document-level discourse parsing in the Rhetorical Structure Theory (RST) framework. In this formulation, we consider discourse parsing as a sequence of splitting decisions at token boundaries and use a seq2seq network to model the splitting decisions. Our framework facilitates discourse parsing from scratch without requiring discourse segmentation as a prerequisite; rather, it yields segmentation as part of the parsing process. Our unified parsing model adopts a beam search to decode the best tree structure by searching through a space of high-scoring trees. With extensive experiments on the standard English RST discourse treebank, we demonstrate that our parser outperforms existing methods by a good margin in both end-to-end parsing and parsing with gold segmentation. More importantly, it does so without using any handcrafted features, making it faster and easily adaptable to new languages and domains., Accepted to NAACL 2021

Metamaterial absorbers with the resonator/dielectric/metallic-mirror conventional design are often angle-dependent and completely reflective outside the absorption band. Here we propose a novel solution to achieve an angle-insensitive bidirectional absorber operating at the transmission mode using a simple metamaterial system. The proposed system is composed of two symmetric disk-pair layers, called the disk-pair dimer, that exhibit two identical but coupled magnetic resonances at the same frequency. This unique design allows to absorb the electromagnetic energy at the transmission mode, which is rarely achievable in conventional ones. By optimizing the coupling strength between two disk-pair layers, the total absorptivity can be enhanced up to 90%.

The reaction of FeCl3, SeO2, and Pyridine (Py) in the presence of methanol (MeOH) under CO pressure generates a black precipitate, which has been confirmed as ferric di-selenide, FeSe2 through different structure characterization methods. Furthermore, impregnation of 5 wt% of FeSe2 onto &gamma, Al2O3 exhibits better catalytic performance than FeSe2 due to the highly dispersed and smaller particle sizes ca. 200&ndash, 300 nm. The reductive carbonylation of nitrobenzene (NB) was investigated over FeSe2/&gamma, Al2O3 as a heterogeneous catalyst, delivering an excellent yield and high selectivity of methyl-N-phenyl carbamate (MPC). Moreover, a set of reactions was performed with variation in the reaction time, temperature, and pressure to investigate the effects of these factors. In particular, FeSe2/&gamma, Al2O3 is highly stable and can be recycled for up to five cycles without significant loss in catalytic performance. A mechanistic study was also conducted on this low-cost catalyst system, especially proposing a crucial role of FeSe2 (&mu, CO) active species.

International audience; In many situations of practical or/and theoretical interest, the assumption that the interfaces between constituent phases of a composite are smooth is no longer appropriate, and the consideration of rough interfaces at microscopic scale is necessary. However, in micromechanics, when the interfaces between the constituent phases of composites become rough, all classical well-known micromechanical schemes resorting to Eshelby's formalism cannot be applicable and the problem of determining the effective properties of composites become largely open. The present work aims to determine the effective thermal conductivity of a composite in which the interfaces between its constituent phases are perfectly bonded but oscillate quickly around a curved surface and along two directions. To achieve this objective, a two-scale homogenization method is proposed. In the first-scale homogenization, or microscopic-to-mesoscopic upscaling, the interfacial zone in which the interface oscillates is homogenized as an equivalent interphase by applying an asymptotic analysis. The thermal properties of the equivalent interphase can generally be determined by using a numerical approach based on the fast Fourier transform (FFT) method. In particular case where the equivalent interphase is very thin, this interphase is then replaced with a general imperfect interface situated at its middle surface. By applying the equivalent inclusion method, every inclusion with imperfect interface is further substituted by an equivalent inclusion with perfect interface. In the second scale homogenization, or mesoscopic-to-macroscopic upscaling, due to the fact that the interfaces are perfect, the effective thermal conductivity can be analytically obtained by using some well-known classical micromechanical schemes. To illustrate the two-scale homogenization method proposed in this work, the case of a layered

Understanding the drivers and income effects of land rental markets is important to facilitate agricultural transformation. This study uses a panel dataset of rural households in Vietnam to examine the efficiency, equity and income effects of land rental markets. Probit and tobit models find that land is transferred from less to more efficient farmers and thus removing administrative barriers to the market operation is suggested. However, instrumental variable and quantile regressions show that the poor do not benefit significantly from participation in the markets. This highlights the need to take care of the poor to ensure that they are not left behind. Further analysis might focus on the efficiency thresholds that farmers switch from a market regime to another.

Kubernetes, an open-source container orchestration platform, enables high availability and scalability through diverse autoscaling mechanisms such as Horizontal Pod Autoscaler (HPA), Vertical Pod Autoscaler and Cluster Autoscaler. Amongst them, HPA helps provide seamless service by dynamically scaling up and down the number of resource units, called pods, without having to restart the whole system. Kubernetes monitors default Resource Metrics including CPU and memory usage of host machines and their pods. On the other hand, Custom Metrics, provided by external software such as Prometheus, are customizable to monitor a wide collection of metrics. In this paper, we investigate HPA through diverse experiments to provide critical knowledge on its operational behaviors. We also discuss the essential difference between Kubernetes Resource Metrics (KRM) and Prometheus Custom Metrics (PCM) and how they affect HPA&rsquo, s performance. Lastly, we provide deeper insights and lessons on how to optimize the performance of HPA for researchers, developers, and system administrators working with Kubernetes in the future.

Background Multidetector computed tomography (MDCT) angiography is a useful examination to detect the source of the bleeding in patients with hemoptysis. The aim of the study was to prospectively evaluate the role and clinical efficacy of MDCT angiography before bronchial artery embolization (BAE) for the management of hemoptysis, and to investigate the predictors of early recurrence. Methods It is a double-center study which included 57 hemoptysis patients undergoing MDCT angiography prior to BAE from August 2019 to July 2020. A prospective analysis of culprit arteries detected by MDCT angiography allowed an evaluation of the role of this technique. A follow-up was done to assess the efficacy of BAE with preprocedural MDCT angiography and to explore the risk factors of early recurrent hemoptysis. Results The accuracy of MDCT angiography in the identification of culprit arteries was as high as 97.5%. The average number of total culprit arteries per patient was 2.75 ± 1.73. Among which, the average numbers of culprit ectopic bronchial arteries (BAs) and non-bronchial systemic arteries (NBSAs) per patient were 0.21 ± 0.41 and 1.04 ± 1.57, respectively. The immediate clinical success rate, total hemoptysis recurrence rate, and early hemoptysis recurrence rate of BAE following MDCT angiography were 94.7, 18.5, 16.7%, respectively. Aspergilloma (HR = 6.63, 95% CI: 1.31–33.60, p = 0.022) was associated with an increase in the risk of early recurrence. Conclusions MDCT angiography should be performed before BAE for the management of hemoptysis. Aspergilloma was an independent predictor for early recurrence.

Recently, various environmental-friendly materials have been investigated and developed, especially composites of polylactic acid (PLA) and plant fibers. This paper investigates the effects of pulp fiber (PF) and epoxidized Tung oil (ETO) content on the properties of biocomposites, based on polylactic acid. The bleached pulp fiber reinforced PLA (PLA/PF) composites with 10–50 wt% fiber contents and 0–15% epoxidized Tung oil contents (with a certain number of fiber) were prepared in an internal mixer (Plastograph® EC) at 150 °C. The mechanical properties of PLA/PF composites were improved significantly. The pulp fiber reinforced PLA composites, with the fiber content of 30 wt%, were found to have the highest mechanical properties. The tensile and flexural properties of PLA/Tung oil-soaked-pulp fiber composites were higher than those of PLA/Tung oil unsoaked pulp fiber composites. In addition, the degradation temperature of PLA-based composites decreased after adding more pulp fiber. The pulp fibers were well-dispersed in the PLA matrix with the content up to 30 wt%. The interaction between pulp fiber and PLA matrix improved by the addition of epoxidized Tung oil. Epoxidized Tung oil also improved tensile and flexural strength of composite materials when it was added with a number of below 10% of fiber.

Behaviors of migrants towards shocks are worthy to study to understand their reflection on external unexpected events to narrow the gap in the literature of migrations. Besides, rural development policies are believed to help reverse the rural-urban migration. This research paper was aimed at taking these critical points from literature into examination for justifications such as impacts of shocks, rural development interventions, and other determinants on migrants’ decision to return and staying duration in the cities with an empirical analysis from the unique Thailand – Vietnam Socio-Economic Panel (TVSEP) data. The estimation results from the two-step Heckman model show that demographic shocks positively affect migrants’ decision to return, while social shocks affecting the migrants during the time in the cities are negatively impact their decision to return. In the outcome stage of migration period, the result signifies that economic shocks positively influence migrants’ staying period in the cities. Besides, migrants from poor communes with poverty reduction projects are more unlikely to return. This implies that current rural development policies in Vietnam with a goal of poverty reduction might not be attractive or efficient enough to fill the gap between the rural and urban regions.

A new orthogonal decomposition of strain tensor into compressive/tensile parts is implemented in the phase eld model to maintain the physical crack propagation behavior. An e cient operator split scheme with the introduction of projection tensors is proposed to facilitate the numerical implementation of the new spectral decomposition. Formulations of the present failure model accounting the unilateral contact condition are given analytically and explicitly, which implies an extremely robust computational model. In particular, compared to the existing models, the present framework is general, which can be applied to all possible elastic behavior, such as isotropic, orthotropic, and totally anisotropic elastic material. A detailed comparison of fracture response predicted by the present models with the literature approaches is then provided. It is shown that orthogonal decomposition is able to simulate various failure scenarios. Especially, this formulation shows a very remarkably prediction compared to experimental observation for the case of compression load.

We propose a novel constituency parsing model that casts the parsing problem into a series of pointing tasks. Specifically, our model estimates the likelihood of a span being a legitimate tree constituent via the pointing score corresponding to the boundary words of the span. Our parsing model supports efficient top-down decoding and our learning objective is able to enforce structural consistency without resorting to the expensive CKY inference. The experiments on the standard English Penn Treebank parsing task show that our method achieves 92.78 F1 without using pre-trained models, which is higher than all the existing methods with similar time complexity. Using pre-trained BERT, our model achieves 95.48 F1, which is competitive with the state-of-the-art while being faster. Our approach also establishes new state-of-the-art in Basque and Swedish in the SPMRL shared tasks on multilingual constituency parsing., Comment: Accepted at ACL 2020

Cordyceps is a precious herb in the world; it was discovered in the Tibetan Plateau of China. It has many good uses for human health as used to replenish the kidney and soothe the lung for the treatment of fatigue, night sweating, homosexualities, hyperglycemia, hyperlipidemia, asthenia after severe illness, respiratory disease, renal dysfunction and renal failure, arrhythmias, and other heart diseases, and liver disease. Due to the production of natural cordyceps exploited each year is increasingly scarce and depleted in recent times. Therefore currently, the cultivation of this herb has been applied to meet the higher demand of the market. Using microcontrollers to monitor and manage environmental parameters such as light, temperature and humidity, and soil moisture, we have produced medicinal substances from cordyceps of similar high quality as natural products.

The geometrical and electrical features of Ag adsorption armchair silicene nanoribbons structure have been investigated using first-principles calculations. The findings reveal that the bandgap of doped Ag has changed, as it does for chemical adsorption on the surface of ASiNRs; this material became metallic at the valance band contact fermi level, with a mean bandgap of 0 eV. Furthermore, the survey to discover the best height 6.39 of Ag and 2.26 bond length Si-Si and Si-Si-Si bond angle 115015’ with structural stability near to the pristine situation has shown promising results for developing novel spintronic and optoelectronic materials in the future.

This project refers to the research, design, and manufacturing of an oxygen aerator prototype for shrimp farming using solar energy. An offline solar system is calculated, designed to drive a 24VDC motor that rotates the propellers to generate oxygen in shrimp ponds. This system is researched for shrimp farming areas without electricity in order to expand shrimp farming capacity for coastal areas. The system can connect to the phone via Bluetooth to transmit the model’s parameters to the user interface. An app that connects the phone to the oxygen aerator is also designed to control and monitor data. Solar-powered oxygen aerators for shrimp ponds can help farmers save 2 to 3 times the cost compared to gas and oil-powered oxygen aerators.

Solar energy has now been applied to provide energy in many different fields around the world. In Vietnam, many solar energy projects are being implemented. In this transdisciplinarity research, research team and local stakeholders participate in designing a solar application to power a fruit and vegetable refrigerator located at Cu lao Rua, Thanh Hoi commune, Tan Uyen Town, Binh Duong province, Vietnam for the poor worker living in the disadvantaged localities with difficulties due to the impact of the Covid-19 pandemic. This is considered a community development project with the use of renewable energy, contributing to environmental protection of the new rural commune.

This paper talks about the research, design, and manufacturing of a tidal power generator prototype. This model is built to take advantage of tidal changes in the Southwest region of Vietnam. Here, the Mekong River has a tidal regime with high water and low water level every day. The difference in potential energy between the high tide and the low tide is utilized to generate the kinetic energy of the blades of the tidal generator turbine. The generated electricity will be stored in a lithium battery, combined with a system that transmits information to the phone via Bluetooth.

Traffic safety is a legitimate and vital necessity in the current life of everyone in the world. For developed countries, the transport infrastructure system is basically invested, the traffic law is also stable due to the process of testing and applying for a long time. For developing countries, by studying the Vietnam database, we assess that the reality of road traffic in general and railways, in particular, is still quite inadequate. Although the Government has actively applied many measures, people are still insecure when traveling on the road because there are still many unfortunate accidents every day. In particular, there are many places where people open new roads to cross the tracks, causing traffic jams and affecting people’s lives and properties. In this project, we use solar panels to power the microcontroller circuit to work. They have the function of alarming, closing, and opening barriers when trains pass by to reduce loss of life and property from accidents, combined with the use of solar energy to make installation easier in mountainous areas, on the other hand, contribute to environmental protection in the future.

The catalytic depolymerization of alkali lignin dissolved in a mixed solvent of ionic liquid (N-allylpyridinium chloride, [Apy]Cl) and water, with ZrO2/SO42– or Pt-ZrO2/SO42– catalyst, were performed in a continuous flow fixed-bed reaction system at low temperature (from 150 to 210 °C). The yields (carbon-based) of total products and phenolic compounds catalyzed by ZrO2/SO42–, which increased with increasing temperature, were 30.6% and 13.4% at 210 °C, respectively. Furthermore, the addition of platinum to the ZrO2/SO42– catalyst enhanced the depolymerization of alkali lignin. In the case of Pt-ZrO2/SO42–, the yields (carbon-based) of total products and phenolic compounds reached 44.9% and 18.7%, respectively, at 210 °C. Additionally, [Apy]Cl readily dissolved lignin and served as a medium for lignin depolymerization, which improved the reactivity of lignin for the use in the continuous flow system at low temperature.

We present an effective adaptive analysis procedure in terms of isogeometric analysis (IGA) based on locally refined (LR) B-splines for two-dimensional elasticity problems. One major advantage of the adopted LR B-splines over B-splines and non-uniform rational B-splines (NURBS) is the local refinement, which makes it highly suitable for adaptive analysis. The Zienkiewicz–Zhu estimation is used on error estimator based local refinement. The local refinement is implemented by the structured mesh refinement strategy according to the posteriori error estimator. The proposed methodology is further extended to deal with multiple patches, which are applied to represent complicated shapes of structures, and the Nitsche’s method is employed for coupling patches among multiple patches in the present adaptive IGA. The algorithm for adaptive IGA on multiple patches is also derived. We provide a series of numerical examples for benchmarks and complicated configurations to demonstrate the flexibility and accuracy of the model as well as the significant enhancement in adaptive IGA based on LR B-splines. A careful comparison of the numerical results suggests that the adaptive local refinement strategy offers faster convergence rate than that of uniform refinement strategy.

In this paper, we present an effective computational approach that combines an adaptive extended isogeometric analysis (XIGA) method with locally refined (LR) B-splines and level set methods for modeling multiple inclusions in two-dimensional (2D) elasticity problems. The advantage of XIGA is to model inclusions without considering internal inclusion interfaces by additional functions. Multiple level set functions are used to represent the location of inclusion interfaces and to define enrichment functions. Local refinement for adaptive XIGA using LR B-splines is based on the posterior error estimator. We use the strategy of structured mesh refinement to implement local refinement in adaptive XIGA. Numerical experiments for multiple inclusions with complicated geometries are presented to demonstrate the accuracy and performance of the proposed approach. In addition, numerical results indicate that the adaptive XIGA with local refinement achieves faster convergence rate than that of the XIGA with uniform global refinement.

Ti-inserted ordered mesoporous silica SBA-15 (Ti-SBA-15) synthesized by original microwave-assisted method as a support was used to prepare CoMo catalysts to develop a new catalyst with high hydrodesulfurization (HDS) and controlled hydrodearomatization (HDA) activities. The activity tests of catalysts were carried out by using a pressurized fixed-bed flow reactor. 4,6-Dimethyldibenzothiophene (4,6-DMDBT), 1-methylnaphthalene, and phenanthrene were used as model reactants in HDS and HDA, respectively. CoMo/Ti-SBA-15 catalyst showed about 1.35 times of HDS activity and half of HDA activity of CoMo/SBA-15 catalyst. The results of XRD, FT-IR and 29Si-NMR reveal that titanium was successfully inserted into silica framework of SBA-15, and the SBA-15 mesoporous structure was maintained after insertion of titanium. The reduction of molybdenum from Mo6+ to Mo4+ readily occurred with incorporation of titanium, resulting in an increase in Mo4+ species and CoMoS phase on sulfided catalysts. This enhanced the HDS activity of CoMoTiSBA15 catalyst. Moreover, the presence of Ti3+ on CoMo/Ti-SBA-15 was observed, suggesting that TiMoS was formed and played a role as new active sites. CoMoS active slabs with shorter length and higher stacking layer were formed on CoMo/Ti-SBA-15 comparing with CoMo/SBA-15, resulting in the low HDA activity of the former.

To obtain a novel catalyst with high resistances to metal sintering and coke formation in the steam reforming of acetic acid, a series of nickel core-shell catalysts were prepared. The effects of the shell thickness, shell species and core particle size on the catalytic activity in the steam reforming of acetic acid were investigated. The prepared Ni@SiO2, Ni@Al2O3, Ni@CeO2 and Ni@TiO2 catalysts were characterized by BET, XRD, H2-TPR, DTG and HRTEM. The prepared core-shell catalysts showed high resistances to nickel sintering, owing to the protection of the shells, in comparison with bare nickel particles. Ni@SiO2 with a thin shell showed a higher activity than the corresponding catalyst with a thick shell due to the thin silica shell allowing the facile diffusion of reactants and products. Because of the important role of the support in steam reforming reactions, the shell species greatly affected the catalytic activity in the steam reforming of acetic acid. It was demonstrated that an alumina shell was best suited for the steam reforming of acetic acid among the studied shells owing to its excellent water dissociation ability. The Ni@Al2O3-i catalyst showed excellent activity with an almost complete conversion and a hydrogen yield up to 91.2% at 750 °C due to its much smaller nickel particle size. The coke formed on the spent core-shell catalysts after the activity tests was mainly graphic carbon, and the Ni@Al2O3-i catalyst exhibited a superior coke resistance with the smallest amount of formed coke. HRTEM results of Ni@Al2O3-i indicated the alumina shell had a high hydrothermal stability and further confirmed the high sintering resistance in the steam reforming of acetic acid.

In this paper, we propose a new random forest (RF) algorithm to deal with high dimensional data for classification using subspace feature sampling method and feature value searching. The new subspace sampling method maintains the diversity and randomness of the forest and enables one to generate trees with a lower prediction error. A greedy technique is used to handle cardinal categorical features for efficient node splitting when building decision trees in the forest. This allows trees to handle very high cardinality meanwhile reducing computational time in building the RF model. Extensive experiments on high dimensional real data sets including standard machine learning data sets and image data sets have been conducted. The results demonstrated that the proposed approach for learning RFs significantly reduced prediction errors and outperformed most existing RFs when dealing with high-dimensional data.

In this paper, a new approach is developed for structural shape optimization, which consists in coupling the particle swarm optimization (PSO) algorithm and the isogeometric boundary element method (IGA-BEM). The IGA-BEM is based on the combination of the isogeometric analysis (IGA) and the boundary element method (BEM), where Non-Uniform Rational B-Splines (NURBS) are employed as shape functions for geometry parameterization and approximation of the field variables. The method inherits the main advantage of the IGA-based shape optimization, i.e., the control points are used as design variables, thus the design model, analysis model and optimization model are uniformly described with the NURBS, providing easy communication between the three models and resulting in a smooth optimized boundary. However, the main feature of the proposed method is the use of PSO, which provides an attractive gradient-free alternative to complicated sensitivity analysis. The efficiency and accuracy of the proposed approach are demonstrated through four 2D shape optimization examples.

A series of CoMo catalysts supported on various Al2O3 supports added with TiO2 were prepared to investigate the addition effect of TiO2 on formation of an active phase on sulfided CoMo/Al2O3 catalyst. The catalytic activity tests were carried out with hydrodesulfurization (HDS) of 4,6-dimethyldibenzothiophene, hydrodenitrogenation (HDN) of acridine, and hydrodearomatization (HDA) of o-xylene, 1-methylnaphthalene (1-MN), and phenanthrene. A 20 wt % TiO2 added CoMoAlTi20 catalyst showed the lowest hydrogenation activity in HDA of 1-MN and phenanthrene and highest HDS and HDN activities. The property of a support and/or the interaction between active metal and the support significantly affect the formation of active sites for HDS and HDA. The active sites for HDS on sulfided CoMo catalysts were different from those for HDA and/or hydrogenation. The addition of TiO2 enhanced the reduction, the formation, and stacking number of CoMoS active slabs. The finding that desulfurization via the hydrogenation pathway ...

A coupled multiphysics phase field framework is proposed to model anodic dissolution induced by stress corrosion fracture growth at microstructual level. The effects of electrochemical-mechanical processes (including crystal anisotropy) are all taken into account. This new model is based upon: (i) an anisotropic phase transformation model based on a variational formulation to describe material dissolution along preferential directions; (ii) an efficient description of grain boundaries as a smeared cohesive zone; (iii) an explicit approximation to model the different electrochemical behaviors between grain boundary and grain interior. Both intergranular and transgranular stress corrosion cracking is simulated in an efficient manner. The abilities of the proposed model are illustrated through several numerical examples involving a full prediction of complex crack network growth induced by stress corrosion cracking within 2D polycrystaline models.