40 results on '"Konstantina Papadopoulou"'
Search Results
2. Digital interventions to improve adherence to maintenance medication in asthma
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Konstantina Papadopoulou and Ian Gregory
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Immunology ,Immunology and Allergy - Published
- 2023
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3. Bioleaching of Scandium from Bauxite Residue using Fungus Aspergillus Niger
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Kyriaki Kiskira, Theopisti Lymperopoulou, Ioannis Lourentzatos, Lamprini-Areti Tsakanika, Charalampos Pavlopoulos, Konstantina Papadopoulou, Klaus-Michael Ochsenkühn, Fotios Tsopelas, Elias Chatzitheodoridis, Gerasimos Lyberatos, and Maria Ochsenkühn-Petropoulou
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Environmental Engineering ,Renewable Energy, Sustainability and the Environment ,Waste Management and Disposal - Abstract
Bauxite residue (BR) is the main by-product of the alkaline production of alumina from bauxite containing significant amounts of valuable metals such as scandium that belongs to rare-earth elements (REEs), classified by the European Community as critical raw materials (CRMs). BR is considered a hazardous waste due to its huge volume and high alkalinity making its disposal a serious universal environmental problem. The recovery of scandium from Greek BR can be an excellent approach for waste management and resource efficiency of the waste using environmentally friendly biometallurgical methods. In this work, bioleaching of scandium from bauxite residue using the fungus Aspergillus niger was studied. Bioleaching experiments were performed using the Taguchi experimental design, in batch cultures with BR at various pulp densities (1, 5 and 10%, w/v), sucrose concentrations (40, 90 and 140 g/L) and fungus suspension of 2, 4, and 6% v/v under one-step bioleaching condition and subculturing. The highest Sc recovery equal to 46%, was achieved in 20 days at 1% pulp density. Biosorption phenomena were observed during the leaching process. Lactic, acetic, oxalic and citric were the main organic acids identified. Graphical Abstract
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- 2023
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4. An Easily Missed But Life-Threatening Diagnosis: A Case Report of Gorlin Syndrome
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Christoforos S. Kosmidis, Christina Michael, Chrysi Maria Mystakidou, Vasiliki Theodorou, Evanthia Papadopoulou, Konstantina Papadopoulou, Charilaos Koulouris, Nikolaos Varsamis, Georgios Koimtzis, Panagiota Roullia, Marios Ntager, Christina Sevva, Nikolaos Iason Katsios, Ioannis Charalampous, Katerina Zarampouka, and Sofia Baka
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General Medicine - Published
- 2023
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5. Catalytic reduction of Cr(VI) using recovered Silicon from end-of-life photovoltaic panels as a catalyst
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Konstantina Papadopoulou, Charalampos Pavlopoulos, Vasiliki Kyriakopoulou, and Gerasimos Lyberatos
- Abstract
As installed photovoltaic panels (PVP) approach their end of life, the need for a sustainable recovery plan becomes imperative. This work aims to reuse Silicon from End-of-Life PVP as a potential catalyst/photocatalyst for wastewater treatment. PVPs were pretreated thermally (550°C for 30 min). The resulting mixture of glass, silicon, electrodes, and ash was separated into different fractions in a trommel. Recovered Silicon flakes were washed with water, acetone, ΗΝΟ3, and HF in order to obtain pure Si. Then Si was etched through a single stage Ag-assisted Chemical etching process and doped with copper. Doping was performed in aqueous HF solutions containing CuSO4. Photocatalytic reduction of Cr(VI) in the presence of 5mM citric acid was carried out in a 600 mL batch reactor irradiated by a Xenon 150W arc lamp as well as under dark conditions. It was found that in the presence of 1.2 g/L of the Si catalyst, Cr(VI) at an initial concentration of 15 mg/L can be reduced below detection limit (>99%),under dark conditions in 90-240 min, depending on the pH of the solution. Irradiation, however, was shown to inhibit the process, contrary to previous reports that had not examined catalysis in the dark.
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- 2022
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6. Hydrothermal pretreatment optimization for enhanced anaerobic digestion of willow sawdust
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GEORGIA ANTONOPOULOU, MARIA ALEXANDROPOULOU, KONSTANTINA PAPADOPOULOU, and GERASIMOS LYBERATOS
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Lignocellulosic biomass including agricultural and forestry residues such as willow sawdust could be used as feedstock for anaerobic digestion (AD). Hydrolysis has been shown to be the rate-limiting step in the case of AD of such substrates. Although being abundant, since the annual world production of biomass residues exceed 220 billion tons, the main obstacles of their use are the low yields attained, due to the recalcitrant nature of their lignocellulosic content. The application of a pretreatment process prior to AD could improve the hydrolysis and the total methane yield. In this study, hydrothermal pretreatment alone or in combination with HCl, at a chemical loading of 2 g /100 g TS was carried out as a pretreatment method to enhance anaerobic digestion of willow sawdust, through biochemical methane potential (BMP) experiments. For both pretreatment approaches, various temperatures (130.5-229.5 oC) and process times (15.6 -59.4 min) were studied. Following pretreatment, the insoluble solids and the hydrolysates were separated by filtration and fully characterized in terms of their structural and chemical characteristics. BMP experiments showed that the hydrothermal pretreatment alone or in combination with the acid enhanced the methane yields and the higher the temperature or process time, the higher the yields which were obtained.
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- 2022
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7. A Detailed Characterization of Household Municipal Solid Waste
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G. M. Lytras, C. Pavlopoulos, K. Filippou, S. Niakas, E. Melanitou, Konstantina Papadopoulou, Gerasimos Lyberatos, D. Mathioudakis, and Demetris F. Lekkas
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0106 biological sciences ,Potential impact ,Environmental Engineering ,Municipal solid waste ,Waste management ,Renewable Energy, Sustainability and the Environment ,Sample point ,020209 energy ,Sorting ,cardboard ,Sampling (statistics) ,02 engineering and technology ,01 natural sciences ,Food waste ,010608 biotechnology ,visual_art ,0202 electrical engineering, electronic engineering, information engineering ,visual_art.visual_art_medium ,Environmental science ,Mixed waste ,Waste Management and Disposal - Abstract
Purpose: The acquisition of reliable data on Municipal Solid Waste (MSW) composition is very important for the development of environmentally sound, sustainable and economically viable integrated waste management systems. However, no standardized universally accepted waste characterization protocol has been developed, as there are various methodologies described in the relevant literature. In this study, a generic and easy-to-apply MSW sampling and sorting protocol is developed and presented. Methods: The MSW composition characterization was used for the development of an innovative waste management strategy in the Municipality of Halandri (Attica region, Greece). The methodology was applied four times, to study the repeatability of the results, as well as the potential impact of seasonality. In each sampling point one collection bin for each waste stream was employed (mixed waste, recyclables, paper/cardboard and food waste in the region where food waste was separately collected at the source) in order to collect all the separate streams and account for the entire MSW production profile. The sampling points were selected in strictly residential areas (no shops, companies nearby). For 7 consecutive days the content of the bins was collected on a daily basis and transported to a sorting facility, where the content was sorted and weighed. Results: The results repeatedly indicated source separation rates of up to 79% and a level of impurities in the recycling waste source separation and collection streams (recyclables and paper/cardboard) not exceeding 20%. Conclusion: The applied methodology proved to generate accurate results, offering a detailed picture of the Municipal Solid Waste management performance.
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- 2020
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8. Food Waste Valorization Based on Anaerobic Digestion
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D. Mathioudakis, G. M. Lytras, Gerasimos Lyberatos, Konstantina Papadopoulou, and C. Lytras
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0106 biological sciences ,Environmental Engineering ,Municipal solid waste ,Waste management ,Renewable Energy, Sustainability and the Environment ,020209 energy ,02 engineering and technology ,Raw material ,Biorefinery ,01 natural sciences ,Anaerobic digestion ,Food waste ,Biogas ,Biofuel ,010608 biotechnology ,Digestate ,0202 electrical engineering, electronic engineering, information engineering ,Environmental science ,Waste Management and Disposal - Abstract
The rapid urbanization that took place in the last 60 years has led to a dramatic increase in the generation of Municipal Solid Waste (MSW). The biodegradable fraction of MSW mainly consists of food waste (FW) and corresponds to about 50% of the total MSW. The disposal of FW in the environment has become a significant challenge. On the other hand, FW is an excellent substrate for anaerobic digestion (AD). This manuscript reviews the different AD technologies for the treatment of FW. Different types of bioreactors and pretreatment methods used to enhance methane production through AD of FW are discussed. The current review gives special emphasis on the methods for biogas upgrading and on technologies for FW digestate valorization. Food waste valorization through anaerobic digestion offers a wide variety of options in all process steps. From the pre-treatment of the feedstock and the selection of the suitable anaerobic digestion technology to the configuration of the process based on the desired products and the valorization of the generated digestate, the design of an integrated anaerobic digestion plant is a challenging task, which necessitates a systematic design. A systematic approach is necessary for FW valorization. The simple single-stage AD process leads to underutilization of the feedstock. There are plenty of available technologies that could be combined for the development of an integrated biorefinery that will be optimized in terms of FW valorization towards the production of biofuels and high-added value products, while introducing a circularity in the nutrients contained in the FW. FW-to-biofuel conversion technologies are high Technology Readiness Level (TRL—9) technologies and anaerobic digestion is applied worldwide at commercial scale.
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- 2020
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9. 3-dimensional bearing capacity envelopes of bridge shallow foundations on cohesionless soils and scour effects
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Konstantina Papadopoulou
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The effects of the combined loading on the bearing capacity (B.C.) shallow bridge foundations on cohesionless soil are investigated by 2D and 3D finite element analyses (F.E.A.), in conjunction with the main parameters involved, as the embedment depth. For the better visual understanding how the various loading or inherent parameters affect the ultimate B.C. the results of F.E.A. are presented as interaction diagrams of the normalized vertical load, moment and horizontal load. The scour effects on the B.C. of shallow foundation are investigated, through the normalized scour depth.
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- 2022
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10. Melanoma: BRAFi Rechallenge
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Christoforos S. Kosmidis, Konstantina Papadopoulou, Chrysi Maria Mystakidou, Evanthia Papadopoulou, Stylianos Mantalovas, Nikolaos Varsamis, Charilaos Koulouris, Vasiliki Theodorou, Konstantinos Papadopoulos, Christina Sevva, Petrina Miltiadous, Savvas Petanidis, Eleni Georgakoudi, Eleni Papadopoulou, and Sofia Baka
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General Medicine - Abstract
Melanoma is the most aggressive type of skin cancer. Half of melanoma cases are characterized by the mutation BRAF V600. The case presented concerns a 41-year-old patient with locally advanced melanoma, being positive in mutation BRAF V600. The patient underwent surgery and received additional targeted therapy as part of a clinical study. In subsequent disease progression, immunotherapy was used. When the disease progressed again while the patient was in a good performance status, targeted therapy was administered again, and a good response was noted, making the patient reach a statistically significant overall survival, exceeding four years. Targeted therapy has proven to be an important tool in the treatment of melanoma. The use of BRAFi targeted therapy does not exclude the option of readministration at subsequent disease progression (BRAFi rechallenge). Preclinical models suggest that the resistance mechanism of cancer cells to BRAFi therapy bends, as these cell clones lose their evolutionary advantage after stopping BRAFi. Cell clones sensitive to BRAFi may then outcompete, making the treatment effective again. Therapeutical dilemmas in the management of patients with locally advanced melanoma that progresses to metastatic cancer are discussed.
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- 2023
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11. Short-Term Outcomes After Robotic Versus Open Liver Resection: A Systematic Review and Meta-analysis
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Konstantina Papadopoulou, Panagiotis Dorovinis, Stylianos Kykalos, Dimitrios Schizas, Paraskevas Stamopoulos, Gerasimos Tsourouflis, Dimitrios Dimitroulis, and Nikolaos Nikiteas
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Oncology ,Gastroenterology - Abstract
Robotic liver surgery is a novel technique expanding the field of minimally invasive approaches. An increasing number of studies assess the outcomes of robotic liver resections (RLR). The aim of our meta-analysis is to provide an up-to-date comparison of RLR versus open liver resections (OLR), evaluating its safety and efficacy.A systematic search of MEDLINE, Scopus, Google Scholar, Cochrane, and Clinicaltrials.gov for articles published from January 2000 until January 2022 was undertaken.Thirteen non-randomized retrospective and one prospective clinical study enlisting 1801 patients met our inclusion criteria, with 640 patients undergoing RLR and 1161 undergoing OLR. RLR resulted in significantly lower overall morbidity (p0.001), shorter length of hospital stay (p = 0.002), and less intraoperative blood loss (p0.001). Operative time was found to be significantly higher in the RLR group (p0.001). Blood transfusion requirements, R0 resection, and mortality rates presented no difference among the two groups. The cumulative rate of conversion was 5% in the RLR group.The increasing experience in the implementation of the robot will undoubtedly generate more prospective randomized studies, necessary to assess its potential superiority over the traditional open approach, in a variety of hepatic lesions.
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- 2022
12. The Effects of Ascorbic Acid and U-74389G on Renal Ischemia-Reperfusion Injury in a Rat Model
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Michail Sideris, Konstantina Papadopoulou, Dimosthenis Chrysikos, Aikaterini Chairakakis, Evangelos Felekouras, Apostolos Papalois, Constantinos G Zografos, Ioannis Sfiniadakis, Vasileios Karampelias, Theodoros Pittaras, Antonis Galanos, and George C. Zografos
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Cancer Research ,Ischemia ,Ascorbic Acid ,Pharmacology ,Antioxidants ,General Biochemistry, Genetics and Molecular Biology ,chemistry.chemical_compound ,medicine ,Animals ,Rats, Wistar ,Pregnatrienes ,Kidney ,business.industry ,Therapeutic effect ,Histology ,Ascorbic acid ,medicine.disease ,Malondialdehyde ,Rats ,Disease Models, Animal ,medicine.anatomical_structure ,chemistry ,Reperfusion Injury ,Tumor necrosis factor alpha ,business ,Reperfusion injury ,Research Article - Abstract
Background/aim U-74389G and ascorbic acid protect the cells from oxidation. This study aimed to depict their role in ischemia-reperfusion injury in a renal rat model. Materials and methods Sixty Wistars rats were randomized into six groups of 10 animals each. Group A Ischemia 30 min, reperfusion 60 min; Group B Ischemia 30 min, reperfusion 120 min; Group C Ischemia 30 min, ascorbic acid administration, reperfusion 60 min; Group D Ischemia 30 min, ascorbic acid administration, reperfusion 120 min; Group E Ischemia 30 min, U-74389G administration, reperfusion 60 min; Group F Ischemia 30 min, U-74389G administration, reperfusion 120 min. We then collected tissue and blood samples. Results Histology and the significantly decreased malondialdehyde and tumor necrosis factor-α levels indicated that ascorbic acid was superior to U-74389G, at pre-defined time intervals. Conclusion Ascorbic acid and U-74389G ameliorated renal damage induced by ischemia-reperfusion injury, suggesting a therapeutic effect.
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- 2020
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13. Shape Effects on Bearing Capacity of Footings on Two-Layered Clay
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George Gazetas and Konstantina Papadopoulou
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Ring (mathematics) ,Materials science ,Prandtl number ,0211 other engineering and technologies ,Rotational symmetry ,Foundation (engineering) ,Soil Science ,Geology ,Geometry ,02 engineering and technology ,Radius ,010502 geochemistry & geophysics ,Geotechnical Engineering and Engineering Geology ,01 natural sciences ,symbols.namesake ,Shear strength (soil) ,Architecture ,symbols ,Bearing capacity ,Soil mechanics ,021101 geological & geomatics engineering ,0105 earth and related environmental sciences - Abstract
The undrained vertical bearing capacity on a two-layered clay of centrally loaded rigid strip, rectangular and ring footings is studied parametrically with 2D, 3D and axisymmetric finite-element analyses. The shear strength ratio of the two layers and the relative thickness of the uppermost layer with respect to pertinent foundation dimension are the key parameters investigated. In addition, for rectangles and rings the length-to-width (“aspect”) ratio and the ring width to external radius ratio are reported. The results are portrayed in diagrams of bearing capacity and shape modification factors, in the familiar soil mechanics form, along with fitted algebraic expressions to facilitate their numerical use. The failure mechanisms are presented for a number of characteristic cases and are being contrasted with the classical Prandtl failure mechanism, giving additional insight into the mechanics of the problem. The results of the paper can be directly used in practical applications.
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- 2019
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14. Eccentricity Effects on Bearing Capacity of Strip and Square Footings on Two-Layered Clay
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Konstantina Papadopoulou and George Gazetas
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Yield (engineering) ,media_common.quotation_subject ,Soil Science ,Geology ,Geotechnical Engineering and Engineering Geology ,Finite element method ,Square (algebra) ,Architecture ,Bending moment ,Geotechnical engineering ,Bearing capacity ,Eccentricity (behavior) ,Mathematics ,Parametric statistics ,Dimensionless quantity ,media_common - Abstract
The undrained ultimate capacity to combined (M, V) loading of strip and square foundations on a two-layered clay deposit is investigated. Extensive two and threedimensional parametric finite element analyses are carried out in terms of the ratio of the undrained shear strength of two layers, the normalized thickness of the top layer and the normalized load eccentricity. Two basic cases are separately investigated, referring to strength ratios higher or lower than unity. The assumption of effective width of the foundations, to account for eccentricity, generally adopted for homogeneous soil, is extended for two layers. The results are mainly presented in terms of modified bearing capacity factors for strip or square footings for a wide range of dimensionless problem parameters. However, for a better visual understanding of how the bending moment affects the ultimate vertical load failure loci diagrams (“yield surfaces”) in M, V space are also presented. Emphasis is given to developing insight into the particular failure mechanisms of most examined cases.
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- 2019
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15. Anaerobic Digestion of Synthetic Municipal Wastewater (MWW) in a Periodic Anaerobic Baffled Reactor (PABR): Assessment of COD Removal and Biogas Production
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Achilleas Zarkaliou, Christos Kougias, Anna Mokou, Konstantina Papadopoulou, and Gerasimos Lyberatos
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Fluid Flow and Transfer Processes ,Process Chemistry and Technology ,high-rate anaerobic digestion ,municipal wastewater ,PABR ,General Engineering ,General Materials Science ,Instrumentation ,Computer Science Applications - Abstract
The benchmark approach for municipal wastewater treatment is based on biological oxidation. Due to high energy consumption, alternative treatment schemes are proposed, among which anaerobic digestion is the most promising. In this work, the direct anaerobic digestion of municipal wastewater in a high-rate system is examined. The reactor utilized for the study is the periodic anaerobic baffled reactor (PABR). Two distinct experimental cycles were conducted, during which the operational parameters of the PABR were consecutively modified: in the first cycle, six phases were conducted where the hydraulic retention time (HRT) varied from 10 to 1 days, the period T between 2.5 days and 0.25, while the OLR remained constant at values near 1.0 gsCOD/L/d. During the second cycle, four distinct phases were conducted with no switching imposed. The HRT varied from 4 to 1 d. The last experimental phase of both cycles was the most significant, due to feedstock resemblance to raw wastewater. The biogas and the biomethane production rates reached 66.8 L/d and 41.1 L/d, respectively, while the COD reduction rate reached 73.7%. Conclusively, the PABR is a high-rate AD system, capable of treating MWW under extreme operational conditions.
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- 2022
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16. 1358 Quality improvement project in a DGH to improve Blood Borne Viruses (BBV) screening for neonates being discharged to foster care
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Lucy Murray, Katharine McDevitt, Konstantina Papadopoulou, Nikhil Ganjoo, and Reham Hashem
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medicine.medical_specialty ,Quality management ,Foster care ,business.industry ,medicine ,Intensive care medicine ,business - Published
- 2021
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17. Natural Time Analysis of Global Seismicity
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Nicholas Sarlis, Jennifer Perez-Oregon, Efthimios Skordas, Panayiotis Konstantinou Varotsos, Stavros-Richard Christopoulos, and Konstantina Papadopoulou
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Fluid Flow and Transfer Processes ,Process Chemistry and Technology ,General Engineering ,General Materials Science ,natural time ,earthquakes ,order parameter ,criticality ,seismic electric signals ,earthquake nowcasting ,Instrumentation ,Computer Science Applications - Abstract
Natural time analysis enables the introduction of an order parameter for seismicity, which is just the variance of natural time χ, κ1=⟨χ2⟩−⟨χ⟩2. During the last years, there has been significant progress in the natural time analysis of seismicity. Milestones in this progress are the identification of clearly distiguishable minima of the fluctuations of the order parameter κ1 of seismicity both in the regional and global scale, the emergence of an interrelation between the time correlations of the earthquake (EQ) magnitude time series and these minima, and the introduction by Turcotte, Rundle and coworkers of EQ nowcasting. Here, we apply all these recent advances in the global seismicity by employing the Global Centroid Moment Tensor (GCMT) catalog. We show that the combination of the above three milestones may provide useful precursory information for the time of occurrence and epicenter location of strong EQs with M≥8.5 in GCMT. This can be achieved with high statistical significance (p-values of the order of 10−5), while the epicentral areas lie within a region covering only 4% of that investigated.
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- 2022
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18. LCA and LCC of dried and shredded food waste as an alternative fuel for the cement industry
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D. Mathioudakis, Konstantina Papadopoulou, Gerasimos Lyberatos, and Panagiotis Karageorgis
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Cement ,Environmental Engineering ,Waste management ,Scope (project management) ,Construction Materials ,Alternative fuels ,Pollution ,Refuse Disposal ,Food waste ,Waste Disposal Facilities ,Waste Management ,Food ,Life cycle costing ,Business ,Life-cycle assessment - Abstract
The scope of this paper is to examine the environmental and economic performance of an alternative household fermentable waste (HFW) management paradigm, developed within the framework of the HORIZON 2020 project Waste4think. In Greece, the business-as-usual scheme for the management of HFW is its disposal in landfills as part of mixed waste. Waste4think developed an alternative approach based on the benefits of source separation. Specifically, source separated HFW is taken to a drying/shredding plant, located in the municipality, for the production of a high-quality biomass product called FORBI. Alternative approaches have been examined for the exploitation of FORBI. In this work, the use of FORBI as an alternative fuel for the cement industry is assessed using life cycle assessment (LCA) and life cycle costing (LCC) tools. The results show that the proposed HFW management framework performs better than the baseline scenario both in economic and environmental terms. However, focus should be given to the optimisation of the drying/shredding process in order to reduce its energy intensity and environmental loadings.
- Published
- 2021
19. Food Residue Biomass Product as an Alternative Fuel for the Cement Industry
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Kalliopi Papanikola, Alexandros Katsiampoulas, Elefterios Chalarakis, Ioannis Michalopoulos, Konstantina Papadopoulou, D. Mathioudakis, Martha Georgiopoulou, Vasiliki Rontogianni, Irene Fotinopoulou, Christos Tsiliyannis, G. M. Lytras, and Gerasimos Lyberatos
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Health, Toxicology and Mutagenesis ,alternative fuel ,010501 environmental sciences ,cement industry ,01 natural sciences ,Residue (chemistry) ,Bioreactors ,Metals, Heavy ,Environmental Chemistry ,European commission ,Biomass ,0105 earth and related environmental sciences ,Cement ,Greece ,Construction Materials ,co-processing ,Construction Industry ,Co-processing ,Heavy metals ,Mercury ,General Medicine ,Pulp and paper industry ,Alternative fuels ,Pollution ,Refuse Disposal ,Food waste ,Food ,Environmental science ,Heat of combustion ,Chlorine ,Food Residue Biomass (FORBI) - Abstract
The present study focuses on the production of an Alternative Fuel (AF) for the cement industry from a Food Residue Biomass (FORBI) product, generated from pre-sorted Household Food Waste (HFW). FORBI is generated by drying and shredding the fermentable fraction of HFW collected door-to-door in the Municipality of Halandri, Greece. The key physicochemical properties such as the net calorific value (NCV), the concentration of heavy metals and chlorine are subsequently determined using well-established international standards (EN and ISO). FORBI is evaluated as a potential AF in terms of technical feasibility and environmental impacts. Based on the characterization, FORBI is classified as a non-dangerous waste according to EWC 20 01 08, European Commission Decision 2014/955. According to EN 15359 it is classified as category 3, 2 and 1 with respect to NCV, Cl and Hg respectively. The study concludes that FORBI is a suitable candidate as a secondary fuel for the cement industry, given its high calorific value along with its low humidity and ash content. Challenges for practical implementation include the relatively high chlorine content, the inclusion of alkalis in the cement produced and the reduction of non-thermal NOx emissions., The data set of the publication can be accessed at: http://doi.org/10.5281/zenodo.3906241
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- 2020
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20. Experimental and numerical assessment of the hydraulic behavior of a pilot-scale Periodic Anaerobic Baffled Reactor (PABR)
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Gerasimos Lyberatos, G. Seintis, G. Pashos, T. Kamperidis, Ioannis Michalopoulos, Konstantina Papadopoulou, Andreas G. Boudouvis, and C. Lytras
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Materials science ,business.industry ,General Chemical Engineering ,Nuclear engineering ,0208 environmental biotechnology ,Mixing (process engineering) ,Pilot scale ,Continuous stirred-tank reactor ,02 engineering and technology ,010501 environmental sciences ,Computational fluid dynamics ,Residence time distribution ,01 natural sciences ,020801 environmental engineering ,Computer Science Applications ,Wastewater ,Plug flow reactor model ,business ,Anaerobic exercise ,0105 earth and related environmental sciences - Abstract
A major factor that determines the mixing pattern inside a reactor is the Residence Time Distribution (RTD). The aim of this paper is the study of the hydraulic behavior of a pilot-scale Periodic Anaerobic Baffled Reactor (PABR) through experimental RTD tests and the development of a CFD model. The tank in series model was used for the determination of the equivalent number (NR) of Continuous Stirred Tank Reactors (CSTR) that simulates the mixing pattern. The hydraulic “dead” space (Vd) was also calculated. Both experimental and simulation results indicate the flexibility of the reactor to perform as a CSTR (NR= 1, Vd= 38.6%–39.6%), as a Plug Flow Reactor (PFR) (NR= 10–16, Vd= 25%–35.4%) or intermediate between the two, depending on the operating parameters. The CFD model can be used for the optimization of the reactor's geometry and for the selection of the optimal operating parameters depending on the type of wastewater to be treated.
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- 2018
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21. Anaerobic Co-digestion in a Pilot-Scale Periodic Anaerobic Baffled Reactor (PABR) and Composting of Animal By-Products and Whey
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Konstantina Papadopoulou, I. Premetis, S. Michalakidi, D. Mathioudakis, Ioannis Michalopoulos, and Gerasimos Lyberatos
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0106 biological sciences ,Environmental Engineering ,Hydraulic retention time ,Renewable Energy, Sustainability and the Environment ,Compost ,Chemistry ,020209 energy ,02 engineering and technology ,engineering.material ,Pulp and paper industry ,01 natural sciences ,Manure ,Anaerobic digestion ,Biogas ,010608 biotechnology ,visual_art ,0202 electrical engineering, electronic engineering, information engineering ,engineering ,Bioreactor ,visual_art.visual_art_medium ,Sawdust ,Waste Management and Disposal ,Cow dung - Abstract
The combination of anaerobic digestion and composting is examined as an integrated valorization process of the livestock waste generated in rural areas. Both biogas and high quality compost may be produced by such a combined process. Six different kinds of waste (pig manure, cow manure, cattle manure, poultry manure, sheep manure and whey) were mixed considering the annual waste production of Metsovo region, Greece, in a representative way. The feed was subjected to a solids/liquid separation step. The bioreactor was operated in different phases with different organic loadings of the liquid fraction of the waste. During phase #1, the Periodic Anaerobic Baffled Reactor (PABR) was fed with a hydraulic retention time (HRT) of 10.65 days, (an organic loading rate of 0.83 g-COD Lreactor−1 day−1) and the biogas production rate was 0.2 Lbiogas Lreactor−1 day−1. During phase #2, the organic loading rate was increased to 1.9 g-COD Lreactor−1 day−1. The biogas production rate was 0.41 Lbiogas Lreactor−1 day−1. During phase #3, the organic loading rate was increased to 2.69 g-COD Lreactor−1 day−1 by decreasing the HRT to 6 days, resulting in the kinetic limitation of the process. The biogas production rate increased to 0.68 Lbiogas Lreactor−1 day−1 with an average methane composition of 65%. The experimental results obtained were used as a basis for the development of an ADM1 model (Batstone et al. in Anaerobic digestion model no. 1 (ADM1). IWA Task Group for Mathematical Modelling of Anaerobic Digestion Processes Report no 1, vol 1(1), 2002) that was able to adequately simulate the operation of the bioreactor. The solid fraction of the pretreatment step was mixed with sawdust and fed to a closed-vessel composter. The highest temperature (56.2 °C) was reached in 2 days. The germination index (GI) of the compost produced was 77.8%, meaning that it was free of phytotoxic substances.
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- 2017
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22. Valorization of the Liquid Fraction of a Mixture of Livestock Waste and Cheese Whey for Biogas Production Through High-rate Anaerobic Co-digestion and for Electricity Production in a Microbial Fuel Cell (MFC)
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D. Mathioudakis, Ioannis Michalopoulos, Martha Georgiopoulou, Asimina Tremouli, Gerasimos Lyberatos, Konstantina Papadopoulou, I. Vaiopoulos, and D. Chatzikonstantinou
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0106 biological sciences ,Environmental Engineering ,Microbial fuel cell ,Waste management ,Renewable Energy, Sustainability and the Environment ,Chemistry ,Substrate (chemistry) ,010501 environmental sciences ,Raw material ,01 natural sciences ,Manure ,Electricity generation ,Wastewater ,010608 biotechnology ,Waste Management and Disposal ,Cow dung ,Anaerobic exercise ,0105 earth and related environmental sciences - Abstract
The objective of this work is the evaluation of two alternative ways of valorizing the liquid fraction of a mixture of different kinds of livestock waste and cheese whey, namely (a) biogas production through the anaerobic co-digestion of in a Periodic Anaerobic Baffled Reactor (PABR) and (b) electrical energy generation in a Microbial Fuel Cell (MFC). The different kinds of livestock manure (pig manure, cow manure, poultry manure, sheep manure and cheese whey) were collected from the region of Metsovo, Greece. The mixture was passed through a pretreatment process producing a liquid fraction that was treated (a) in a pilot-scale Periodic Anaerobic Baffled Reactor (PABR) for methane production and (b) in a lab-scale two-chamber Microbial Fuel Cell for electricity production. In the present study, the experimental data obtained from a previous study [1] were used for the evaluation of a simple mathematical model, based on Monod kinetics, for the PABR using Aquasim 2.1 [2]. The simple model was able to satisfactorily describe the behavior of the PABR in terms of soluble COD consumption. In addition, the same liquid waste, filtered (0.70 μm) and diluted at different initial concentrations, was used as feedstock for electricity production, using a two-chamber microbial fuel cell (MFC). The experiments showed that the MFC performance was not limited by the wastewater strength, since the substrate removal efficiency and the maximum power density were not affected by an increase of the initial concentration. The required time showed a linear relationship with the initial concentration of the substrate.
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- 2017
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23. Hydrogen and Methane Production from Food Residue Biomass Product (FORBI)
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C. Lytras, D. Mathioudakis, A. Goumenos, Konstantina Papadopoulou, Ioannis Michalopoulos, G. M. Lytras, I. Zacharopoulos, and Gerasimos Lyberatos
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0106 biological sciences ,Acidogenesis ,Environmental Engineering ,020209 energy ,02 engineering and technology ,Raw material ,7. Clean energy ,01 natural sciences ,Methane ,Volatile Fatty Acids ,chemistry.chemical_compound ,Biogas ,010608 biotechnology ,Dark Hydrogen Fermentation ,0202 electrical engineering, electronic engineering, information engineering ,Bioreactor ,Waste Management and Disposal ,Hydrogen production ,Renewable Energy, Sustainability and the Environment ,Anaerobic Digestion ,Pulp and paper industry ,6. Clean water ,Food waste ,chemistry ,13. Climate action ,Food Residue Biomass ,Environmental science ,PABR ,Hydrogen ,Mesophile - Abstract
This study concerns the production of hydrogen and methane from a Food Residue Biomass (FORBI) product (Papanikola et al. in 5th international conference on sustainable waste management systems, Athens, 2017), generated from pre-sorted HFW in a CSTR and in a PABR respectively. FORBI is generated by drying and shredding the fermentable fraction of household food waste collected door-to-door in the Municipality of Halandri, Greece. Hydrogen production from FORBI through anaerobic fermentation under acidogenic mesophilic conditions was carried out using a 4 L CSTR, operated at 12 h HRT under an organic loading of 15 g TS L−1. The H2-CSTR was operated for 40 days. During the operation of H2-CSTR the production of biogas reached up to 0.1026 Lbiogas gFORBI−1 and the percentage of hydrogen in the gas up to 48.2%. The conversion of FORBI into methane was carried out through the operation of a 77 L PABR operated under mesophilic methanogenic conditions at various operating parameters (OLR, HRT, T). Two different approaches were adopted for the pre-treatment of the feedstock. For the two first phases of the experimental procedure, a liquid extraction step was carried out before feeding the bioreactor with the separated liquid fraction, while in the subsequent three phases, a whole suspension of FORBI was used as feed. The mean biogas production rate was 0.158 ± 0.02 Lbiogas gFORBI−1 and the mean methane percentage in the biogas was 67.5 ± 2.1%, in the first two phases. The mean biogas production rate was 0.519 ± 0.03 Lbiogas gFORBI−1 and the mean methane percentage in the biogas was 66 ± 2.8%, when a whole suspension of FORBI was fed to the PABR.
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- 2019
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24. Factors Affecting the Behaviour of Retaining Structures with Prestressed Anchorages Under 2D and 3D Conditions
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Alexandros Sofianos and Konstantina Papadopoulou
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021110 strategic, defence & security studies ,Safety factor ,Horizontal and vertical ,Parametric analysis ,business.industry ,0211 other engineering and technologies ,Soil Science ,Geology ,02 engineering and technology ,Structural engineering ,Geotechnical Engineering and Engineering Geology ,Lateral earth pressure ,Slope stability ,Architecture ,Geotechnical engineering ,business ,021101 geological & geomatics engineering ,Mathematics - Abstract
Some basic factors which influence the behaviour of the anchored retaining structures are investigated and 2D analyses with three dimensional ones are compared. The parametric analysis under 2D conditions focuses on the influence of significant factors such as the normalized embedded depth of the wall, the resistance of the anchors, the free tendon length, the earth pressure coefficient at rest and the flexibility of the system, on the behaviour of the retaining structure. The analyses are performed in two groups for two representative soil types named S1 (weathered weak rock) and S2 (very stiff clay). Qualitative as well as quantitative conclusions are derived from the analyses concerning the influence of the above mentioned factors, mainly on the safety factor as well as on the displacements. The 3D analyses are carried out for various ratios L/H, where L is the length and H the height of the slope. Several trends are confirmed from the results concerning the influence of the above-mentioned factors. It is concluded that the triaxal conditions strongly affect the safety factor, as well as the distribution of horizontal and vertical displacements, mainly in the cases where the ratios L/H ≤ 2. Some serious deviations between 2D and 3D analyses are pointed out and the physical explanation of these differences is given for several cases.
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- 2016
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25. Assessment of Pleurotus ostreatus mediated degradation of agro-residues by using design of experiments methodologies
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Konstantina Papadopoulou, Fotis Rigas, and Vassilis Dimitropoulos
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Environmental Engineering ,biology ,Central composite design ,Renewable Energy, Sustainability and the Environment ,business.industry ,General Chemical Engineering ,Lignocellulosic biomass ,Factorial experiment ,Straw ,biology.organism_classification ,Pulp and paper industry ,Biotechnology ,chemistry.chemical_compound ,chemistry ,Environmental Chemistry ,Lignin ,Pleurotus ostreatus ,Response surface methodology ,Cellulose ,business ,Waste Management and Disposal ,General Environmental Science ,Water Science and Technology ,Mathematics - Abstract
Aim Lignocellulosic biomass, mostly by agricultural and forestry sources, mainly consists of cellulose, hemicelluloses, and lignin. White rot fungi are known to be efficient degraders of cellulose due to their ligninolytic enzyme system. The use of Pleurotus ostreatus AMRL 141 as a biological treatment of wheat straw (WS) was explored to determine the most significant variables affecting the cultivation of fungus. Methods Two experimental designs were applied: firstly, a 2-level factorial design (screening) with 7 variables and 3 responses and a central composite design with 4 variables and 3 responses. The optima of the statistically adequate models obtained for a 2 weeks cultivation period were then found. The solid state medium used was sandy soil mixed with agricultural residue (milled WS). Results Overall, the results of many previous studies of our research group have proved that Pleurotus ostreatus is an efficient lignocellulosic decomposer. In this study, design of experiments methodologies were successfully used and the optimum values of responses found for the two weeks cultivation period were lag time (2 days), extent of colonization (46 mm), and propagation velocity (3 mm d−1). © 2015 American Institute of Chemical Engineers Environ Prog, 2015
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- 2015
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26. An alternative management of biowaste for biomass production
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Prof. Gerasimos Lyberatos, Dr. Konstantina Papadopoulou, Dr. Ainhoa Alonso, Marta Vila, and Edurne Fernández
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- 2018
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27. Finite Element Analyses and Experimental Investigation of Helical Micropiles
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Konstantina Papadopoulou, Harris Saroglou, and Vasileios P. Papadopoulos
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Geotechnical investigation ,Engineering ,Hydrogeology ,business.industry ,Full scale ,Rotational symmetry ,Shell (structure) ,Soil Science ,Geology ,Structural engineering ,Geotechnical Engineering and Engineering Geology ,Finite element method ,Shear strength (soil) ,Architecture ,Ultimate tensile strength ,Geotechnical engineering ,business - Abstract
Within the framework of a research program on the behaviour of a specific type of screw micropile with helical plates of 220 mm diameter, the response in axial and horizontal loadings by the finite element method and full scale in situ tests were investigated. For the axial compressive or tensile loads, the simulation of the helical plates was carried out under axisymmetric conditions as shell foundations. The cases of purely cohesive or cohesionless soils with linear elastic–perfectly plastic behaviour were studied. The influence of shear strength parameters and the number of helical plates on the characteristic-ultimate resistance were also analyzed. For the horizontal loads 3D F.E. programs were applied for the analyses of the micropiles either as short or long ones. The in situ tests, which are presented in this article, were performed in two areas with representative subsoil conditions. The respective predictions from the F.E. method were based on results of geotechnical investigations and compared with the results of the in situ tests. A good approximation was ascertained, especially for uplift and horizontal loads and the differences were commented.
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- 2014
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28. Optimization of fungal decolorization of azo and anthraquinone dyes via Box-Behnken design
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Fotis Rigas, Antonios Philippoussis, Konstantina Papadopoulou, and Iphigeneia Maria Kalagona
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Mushroom ,Pleurotus ,Chromatography ,biology ,Pleurotus pulmonarius ,biology.organism_classification ,Pulp and paper industry ,Microbiology ,Remazol Brilliant Blue R ,Anthraquinone ,Box–Behnken design ,Biomaterials ,chemistry.chemical_compound ,chemistry ,Response surface methodology ,Waste Management and Disposal ,Mycelium - Abstract
Dyes released by the textile industries pose a threat to environmental quality. Ligninolytic white-rot fungi can effectively decolorize colored effluents and conventional dyes. The present study investigates the ability of eleven strains belonging to Pleurotus, Ganoderma and Lentinula mushroom genera in the decolorization of eight textile azo and anthraquinone dyes added in solid-plate cultures. Pleurotus pulmonarius AMRL 177, showing the greatest decolorization ability, was further investigated for Remazol Brilliant Blue R (RBBR) decolorization using response surface methodology (RSM). RSM involved Box-Behnken design matrix for three design factors: dye concentration, nitrogen concentration and copper concentration were successfully employed for the optimization of four responses: lag time, mycelium extension rate, decolorization rate and laccase activity. Optimum values of responses obtained were: lag time 3 days, mycelium extension rate 2.8 mm d−1, decolorization rate 2.7 mm d−1 and laccase activity 480 U ml−1.
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- 2013
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29. Bioremediation of Lindane Contaminated Soil by Pleurotus ostreatus in Non Sterile Conditions Using Multilevel Factorial Design
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Antonios Philippoussis, Konstantina Papadopoulou, J. Chatzipavlidis, Fotis Rigas, and M. Papadopoulou
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Environmental Engineering ,biology ,Ecological Modeling ,Factorial experiment ,Biodegradation ,Straw ,biology.organism_classification ,Pollution ,chemistry.chemical_compound ,Bioremediation ,chemistry ,Environmental chemistry ,Environmental Chemistry ,Pleurotus ostreatus ,Microbial biodegradation ,Lindane ,Landfarming ,Water Science and Technology - Abstract
A commercial strain of the fungus Pleurotus ostreatus was used to mediate the degradation of lindane, by landfarming technology during a 4 weeks statistical experiment. The Multilevel Factorial Design was used with two design factors, namely, straw content X 1 (%) and lindane content X 2 (ppm). The optimization parameters (responses) investigated were: biodegradation rate Y 1 (μg d−1), biomass growth rate Y 2 (mg d−1), biodegradation/biomass Y 3 (μg mg−1), total organic carbon Y 4 (%), total organic nitrogen Y 5 (%) and total organic carbon/total organic nitrogen Y 6. The optima of the adequate models obtained for the period of 2 and 4-weeks were found. An overall kinetic study, conducted in this work with the aid of experimental design, determined the optimum (maximum) specific lindane degradation rate to be 0.16 g kg−1 month−1.
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- 2008
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30. Citizen Perspectives on the Development of Local Cultural Resources: The Case of the Municipality of Serres
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Eleni Tsolaki, Charalampos Zilianakis, Katerina Lazaridou, Konstantina Papadopoulou, Ioannis Samoladas, and Dafni-Maria Nerantzaki
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Value (ethics) ,Economic growth ,business.industry ,media_common.quotation_subject ,Environmental resource management ,Sample (statistics) ,Context (language use) ,Cultural tourism ,Geography ,State (polity) ,Order (exchange) ,Local economy ,Cultural development ,business ,media_common - Abstract
Nowadays, cultural development is considered to be a matter of high priority for a modern state. Local cultural assets play a major role in the design and development of a successful and sustainable national cultural development policy. The purpose of the current survey is to explore to what extend people who are residents at the Municipality of Serres realize the importance of cultural assets in the context both of national or regional economic development and which are these local cultural assets and resources. Additionally, the survey presented, attempts to gain insight into what are the factors that inhibit local cultural development and which are the main driving instructions responsible for the exploitation of these cultural assets and resources. In order to achieve its goals, the survey utilizes a sample of 121 responses to a comprehensive questionnaire, answered mainly by people who are permanent residents at the greater area of the Municipality of Serres. Analysis of the results gave strong evidence that the Municipality of Serres hosts and important number of cultural resources, which are not yet sufficiently exploited and promoted. In addition, citizens realize the important role cultural development can play in local economy and the value it can add in order to advance local economy as a whole.
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- 2016
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31. A systematic review and meta-analysis of experimental clinical evidence on initial aligning archwires and archwire sequences
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Spyridon N. Papageorgiou, Ioannis Konstantinidis, Christoph Bourauel, Andreas Jäger, and Konstantina Papadopoulou
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MEDLINE ,Dentistry ,Orthodontics ,Bias assessment ,Cochrane Library ,law.invention ,Randomized controlled trial ,law ,Nickel ,Orthodontic Wires ,Medicine ,Humans ,Titanium ,business.industry ,Confidence interval ,Treatment Outcome ,Otorhinolaryngology ,Data extraction ,Clinical evidence ,Meta-analysis ,Surgery ,Oral Surgery ,business ,Copper ,Dental Alloys - Abstract
The aim of the study was to assess treatment effects and potential side effects of different archwires used on patients receiving orthodontic therapy. Electronic and manual unrestricted searches were conducted in 19 databases including MEDLINE, Cochrane Library, and Google Scholar until April 2012 to identify randomized controlled trials (RCTs) and quasi-RCTs. After duplicate study selection, data extraction, risk of bias assessment with the Cochrane risk of bias tool, and narrative analysis, mean differences (MDs) with confidence intervals (CIs) of similar studies were pooled using a random-effects model and evaluated with GRADE. A total of 16 RCTs were included assessing different archwire characteristics on 1108 patients. Regarding initial archwires, meta-analysis of two trials found slightly greater irregularity correction with an austenitic-active nickel-titanium (NiTi) compared with an martensitic-stabilized NiTi archwire (corresponding to MD: 1.11 mm, 95% CI: -0.38 to 2.61). Regarding archwire sequences, meta-analysis of two trials found it took patient treated with a sequence of martensitic-active copper-nickel-titanium (CuNiTi) slightly longer to reach the working archwire (MD: 0.54 months, 95% CI: -0.87 to 1.95) compared with a martensitic-stabilized NiTi sequence. However, patients treated with a sequence of martensitic-active CuNiTi archwires reported general greater pain intensity on the Likert scale 4 h and 1 day after placement of each archwire, compared with a martensitic-stabilized NiTi sequence. Although confidence in effect estimates ranged from moderate to high, meta-analyses could be performed only for limited comparisons, while inconsistency might pose a threat to some of them. At this point, there is insufficient data to make recommendations about the majority of initial archwires or for a specific archwire sequence.
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- 2014
32. Clinical effects of pre-adjusted edgewise orthodontic brackets: a systematic review and meta-analysis
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Christoph Bourauel, Konstantina Papadopoulou, Spyridon N. Papageorgiou, Andreas Jäger, and Ioannis Konstantinidis
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business.industry ,Orthodontic Appliance Design ,Orthodontic Brackets ,Bracket ,MEDLINE ,Dentistry ,Orthodontics ,Confidence interval ,law.invention ,Orthodontic brackets ,Randomized controlled trial ,law ,Meta-analysis ,Medicine ,Humans ,Adverse effect ,business ,Randomized Controlled Trials as Topic - Abstract
SUMMARY BACKGROUND: Fixed-appliance treatment is a major part of orthodontic treatment, but clinical evidence remains scarce. OBJECTIvES: Objective of this systematic review was to investigate how the therapeutic effects and sideeffects of brackets used during the fixed-appliance orthodontic treatment are affected by their characteristics. SEARCh METhODS AND SElECTION CRITERIA: We searched MEDlINE and 18 other databases through April 2012 without restrictions for randomized controlled trials and quasi-randomized controlled trials investigating any bracket characteristic. DATA COllECTION AND ANAlYSIS: After duplicate selection and extraction procedures, risk of bias was assessed also in duplicate according to Cochrane guidelines and quality of evidence according to the Grades of Recommendation. Assessment, Development and Evaluation approach. Random-effects meta-analyses, subgroup analyses, and sensitivity analyses were performed with the corresponding 95 per cent confidence intervals (CI) and 95 per cent prediction intervals (PI). RESUlTS: We included 25 trials on 1321 patients, with most comparing self-ligated (S l) and conventional brackets. Based on the meta-analyses, the duration of orthodontic treatment was on average 2.01 months longer among patients with S l brackets (95 per cent CI: 0.45 to 3.57). The 95 per cent PIs for a future trial indicated that the difference could be considerable (−1.46 to 5.47 months). Treatment characteristics, outcomes, and side-effects were clinically similar between S l and conventional brackets. For most bracket characteristics, evidence is insufficient. Some meta-analyses included trials with high risk of bias, but sensitivity analyses indicated robustness. CONClUSIONS: Based on existing evidence, no clinical recommendation can be made regarding the bracket material or different ligation modules. For S l brackets, no conclusive benefits could be proven, while their use was associated with longer treatment durations.
- Published
- 2013
33. The time-dependent biomechanical behaviour of the periodontal ligament--an in vitro experimental study in minipig mandibular two-rooted premolars
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Andreas Jäger, Rolf Krause, Konstantina Papadopoulou, Christoph Bourauel, Theodore Eliades, Ludger Keilig, University of Zurich, and Eliades, T
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Dental Stress Analysis ,Materials science ,Linear displacement ,Periodontal Ligament ,Swine ,Dentistry ,610 Medicine & health ,Orthodontics ,Mandible ,10067 Clinic for Orthodontics and Pediatric Dentistry ,Force sensor ,Tooth crown ,stomatognathic system ,Deflection (engineering) ,Premolar ,medicine ,Periodontal fiber ,Animals ,Bicuspid ,Tooth Root ,Tooth Crown ,Force level ,business.industry ,3505 Orthodontics ,Biomechanical Phenomena ,medicine.anatomical_structure ,Swine, Miniature ,Stress, Mechanical ,Maximum displacement ,business - Abstract
The aim of the present work was to evaluate the biomechanical behaviour of the periodontal ligament (PDL) with respect to force development with different controlled loading velocities. For this purpose, an in vitro experimental study was performed on 18 minipig jaw segments. Displacements with variable increasing loading time were applied to one premolar crown of each jaw segment into the linguobuccal direction through a force sensor provided by a specialized biomechanical set-up. The predefined displacement values to be achieved were 0.1 and 0.2 mm. Each of the given displacement increments was applied on the specimens with a linear displacement increase employing the following time spans: 5, 10, 20, 30, 60, 120, 300, 450, and 600 seconds. Force values were measured during load application to register force/displacement diagrams and after the maximum displacement was reached force decay was monitored for a period of 600 seconds. Force/time curves for each tooth were plotted according to the data obtained. Diagrams of the maximum force values obtained from these plots and the force at the end of each measurement were extracted for all teeth. Forces at the point when maximum displacement was reached ranged from 0.5 to 2.5 N for the 0.1 mm activation and showed extreme variation with the specimens. The factor of volume and surface area of the individual roots were evaluated and found not to be responsible for these deviations. A comparable behaviour was recorded for the 0.2 mm deflection, however, on a higher force level. The results show that the force development at different displacement velocities is complex and dominated by the PDL biomechanical characteristics.
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- 2011
34. Biomass, laccase and endoglucanase production by Lentinula edodes during solid state fermentation of reed grass, bean stalks and wheat straw residues
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Konstantina Papadopoulou, Hicham Lakhtar, Sevastianos Roussos, Antonios Philippoussis, G. Parissopoulos, Panagiota Diamantopoulou, and Seraphim Papanikolaou
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Physiology ,Cellulase ,Chemical constituents ,Applied Microbiology and Biotechnology ,Botany ,Enzyme activities ,Food science ,Endoglucanase ,Mycelium ,Laccase ,Glucosamine ,biology ,Strain (chemistry) ,Correlations ,Growth rate ,Chemistry ,General Medicine ,Straw ,biology.organism_classification ,Mycelial biomass ,Lentinula ,Solid state fermentation ,Solid-state fermentation ,biology.protein ,Fermentation ,Lentinula edodes ,Lignocellulosic residues ,Biotechnology - Abstract
Mycelium growth rates, biomass concentration (estimated as glucosamine content) and laccase and endoglucanase secretion were monitored during solid state fermentation (SSF) of wheat straw (WS), reed grass (RG) and bean stalk (BS) residues by Lentinula edodes strains 119, 121, and 122. In a first experiment, these strains were subjected to screening regarding their growth rates and biomass yield, where strain 121 proved to be the fastest colonizer. However, the greater biomass yield at the end of colonization was demonstrated by strain 122 on BS (465.93 mg g(-1) d.w.). In a second experiment, growth characters, as well as endoglucanase and laccase production patterns of the selected strains 121 and 122 were monitored at three intervals i.e., at 33, 66, and 100% of substrate colonization. BS furnished the highest endoglucanase production for strain 121, while RG for strain 122. A strain and substrate-dependent behaviour of the enzyme secretion was detected, with strain 122 presenting maximal endoglucanase activity in all substrates at the initial (33%) and final (100%) stages of colonization (0.64-0.90 and 0.79-0.97 U g(-1,) respectively). However, in strain 121 the peak of endoglucanase production was detected in the early stages of colonization (at 33% on WS and at 66% on RG and BS). Laccase activity showed increased values (maxima on WS, 353.68 and 548.67 U g(-1) by strains 121 and 122, respectively) at 66% of colonization. Correlation analysis of growth data demonstrated negative relations between growth rate and biomass yield and between laccase and endoglucanase activities on WS and RG substrates fermented by strain 122. Finally, possible relations of growth parameters with nutritional constituents of the substrates were investigated.
- Published
- 2011
35. Microbiologically-influenced corrosion of orthodontic alloys: a review of proposed mechanisms and effects
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Konstantina, Papadopoulou and Theodore, Eliades
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Corrosion ,Streptococcus mutans ,Orthodontic Appliances ,Sulfur-Reducing Bacteria ,Genes, Bacterial ,Biofilms ,Polysaccharides, Bacterial ,Leptothrix ,Bacterial Adhesion ,Dental Alloys - Abstract
To summarise the currently available evidence on the effects of microorganisms on the corrosion processes of biomaterials, with specific relevance to orthodontic alloys.Factors related to the micro-environmental milieu, conditions, site characteristics, microbial species, enzymes and compounds released in response to their attachment to surfaces and formation of biofilms are analysed with respect to their contributory roles in corrosion.Application to orthodontics is projected from relevant evidence, albeit hypothetical due to the lack of extensive investigations of the subject. The micro-organisms involved and effects observed in orthodontic alloys are summarised. Finally, protective measures are proposed to minimise the potential for corrosion processes in orthodontic patients.
- Published
- 2009
36. Bioremediation of a soil contaminated by lindane utilizing the fungus Ganoderma australe via response surface methodology
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Konstantina Papadopoulou, D. Doulia, Fotis Rigas, and V. Dritsa
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Insecticides ,Environmental Engineering ,Central composite design ,Nitrogen ,Health, Toxicology and Mutagenesis ,Biomass ,chemistry.chemical_compound ,Bioremediation ,Methods ,Environmental Chemistry ,Soil Pollutants ,Waste Management and Disposal ,Environmental Restoration and Remediation ,Moisture ,Chemistry ,Environmental engineering ,food and beverages ,Ganoderma ,Biodegradation ,Straw ,Pollution ,Soil contamination ,Horticulture ,Kinetics ,Lindane ,Hexachlorocyclohexane - Abstract
Mixtures of a sandy soil and wheat straw were doped with the organochlorine insecticide lindane in glass tubes and were inoculated with the polypore fungus, Ganoderma australe. An evaluation of bioremediation process effectiveness was searched and five parameters identified for the solid-state system. Fungi growth is a function of temperature and requires moisture for a proper colonization. These microorganisms need inorganic nutrients such nitrogen and phosphorus to support cell growth and it is also appropriate to know the range of concentration and toxicity of the used insecticide. Thus, an orthogonal central composite design (CCD) of experiments was used to construct second order response surfaces. Five design factors, namely temperature, moisture, straw, lindane content and nitrogen content and seven optimization parameters (responses), namely lag time, propagation velocity, biomass growth rate, biodegradation rate, biodegradation/biomass, biomass/propagation and biomass content were analyzed. The optima of the responses of the adequate models were found to be the following: propagation velocity 4.25mm/day, biomass growth rate 408mg/day, biodegradation/biomass 56.9microg/g, biomass/propagation 250mg/mm and fungal biomass content in solid mixture 260mg/cm(3). The most important response for bioremediation purposes is biodegradation/biomass which is maximized at the factors levels: temperature 17.3 degrees C, moisture 58%, straw content 45%, lindane content 13ppm and nitrogen content 8.2ppm.
- Published
- 2006
37. Moving towards Life Cycle Thinking by integrating Advanced Waste Management Systems: WASTE4THINK
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'Konstantina Papadopoulou
38. GENERAL REPORT - SESSION 3
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DIEGO CARLO LO PRESTI, Mary, Perlea, NUNZIANTE SQUEGLIA, Konstantina, Papadopoulou, Charles, Bishop, J. r., Monica, Prezzi, Chow, Gary S., Randa Al Asmar, Elizabeth, Gallagher, Alex, Sanzeni, Jósef, Mecsi, Kumars Zand Parsa, and Meyer, Matthew E.
39. Bioelectricity Production from Fermentable Household Waste in a Dual-Chamber Microbial Fuel Cell
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Chatzikonstantinou Dimitra, Tremouli Asimina, Konstantina, Papadopoulou, Kanellos Gerasimos, Lampropoulos Ioannis, and Lyberatos Gerasimos
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13. Climate action ,11. Sustainability ,7. Clean energy ,6. Clean water - Abstract
In this study, the use of a dual chamber microbial fuel cell (MFC) for the production of bioelectricity from a food residue biomass (FORBI) product was investigated. FORBI was produced by drying and shredding the pre-sorted fermentable fraction of household food waste collected door-to-door in the Municipality of Halandri, Athens, Greece. Different organic loads of FORBI were examined (0.7, 0.9, 1.4, 2.8, 6 and 14 g COD L-1 respectively). It was observed that an increase of the initial concentration of the final extract resulted in a corresponding increase in the operating time. The MFC potential increased from 33.3 mV to 46 mV as the concentration was increased from 0.7 to 14 g COD L-1. The best performance in terms of maximum power density (29.6 mW m-2) corresponding to a current density of 88 mA m-2) was observed for 6 g COD L-1. Setting the external resistance at its optimal value (Rext = 2 kΩ) as determined by polarization experiments , Pyield drastically increased to 13.7 and 17.3 Joule (g FORBI)-1 in two consecutive cycles. The results demonstrate that readily biodegradable substrates such as FORBI can be effectively used for enhanced bioelectricity harvesting in an MFC., The data set of the publication can be accessed at: http://doi.org/10.5281/zenodo.3906241
40. Food Residue Biomass Product as an Alternative Energy Source for the Cement Industry
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Kaliopi. Papanikola, Konstantina Papadopoulou, Christos Tsiligiannis, Irini Fotinopoulou, Alexandros Katsiampoulas, Eleftherios Chalarakis, Martha Georgiopoulou, Vicky Rontogianni, Ioannis Mixalopoulos, and Gerasimos Lyberatos
- Subjects
13. Climate action ,11. Sustainability ,7. Clean energy ,12. Responsible consumption - Abstract
In this paper we examine whether food residue biomass can be used as secondary fuel in the cement industry and how we may setup a pilot-scale plant for its processing. We gather samples from household waste in collaboration with the municipality of Haladri. The food residue is shredded and dried, leading to a high homogenous product. Using well-established international standards, we then measure certain key physicochemical properties such as its net calorific value, its concentration in heavy metals and chlorine content. The characterization allows assessment of its suitability as an alternative fuel in terms of economic and technical feasibility as well as environmental impact. This study concludes that food residue biomass is a good candidate as a secondary fuel for the cement industry. Keywords: cement industry, alternative fuel, co-processing, Food Residue Biomass (FORBI).
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