Search results for: trace gases

Authors: Sara Mercedes Barroso Pinzón, Álvaro Jesús Caicedo Castro, Antonio Javer Sánchez Herencia

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In recent years there has been increased academic and industrial research into the development of orthopaedic implants with structural properties and functionality similar to mechanical strength, osseointegration, thermal stability and antibacterial capacity similar to bone structure. Hydroxyapatite has been considered for decades as an ideal biomaterial for bone regeneration due to its chemical and crystallographic similarity to the mineral structure bioapatites. However, the lack of trace elements in the hydroxyapatite structure confers very low mechanical and biological properties. Under this scenario, the objective of the research is the synthesis of hydroxyapatite with Mg from the francolite mineral present in phosphate rock from the central-eastern region of Colombia, taking advantage of the extraction of mineral species as natural precursors of Ca, P and Mg. The minerals present were studied, fluorapatite as the mineral of interest associated with magnesium carbonates and quartz. The chemical and mineralogical composition was determined by X-ray fluorescence (XRF) and X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX); the optimum conditions were established using the acid leaching mechanism in the wet concentration process. From the products obtained and characterised by XRD, XRF, SEM, FTIR, RAMAN, HAp-Mg biocomposite scaffolds are fabricated and the influence of Mg on morphometric parameters, mechanical and biological properties in the formed materials is evaluated.

Keywords: phosphate rock, hydroxyapatite, magnesium, biomaterials

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Authors: Andreia Cucuruz, Cristina Daniela Ghitulica, Georgeta Voicu, Cristina Busuioc

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Ceramics based on calcium phosphates have lately increased attention for tissue engineering because they can be used as substitute bones or for bone regeneration since they mimic very well the nanostructure of tough bone tissue, but also because of other advantages such as a very good biocompatibility and osseointegration. This study aims the preparation and characterization of ceramic materials on the basis of TCP (Ca₃(PO₄)₂), within which calcium ions are substituted by magnesium ions (Mg²⁺) in order to improve the regenerative properties of these materials. TCP-Mg material was synthesized by chemical precipitation method using calcium oxide (CaO) and phosphoric acid (H₃PO₄) as precursors. The objective was to obtain powders with different concentrations of Mg in order to analyze the effect of magnesium ions on the physicochemical properties of phosphate ceramics and in vitro degradation in simulated biological fluid (SBF). Ceramic powders were characterized in vitro but also from the compositional and microstructural point of view. TCP_Mg powders were prepared through wet chemical method from calcium oxide (CaO), magnesium oxide nanopowder (MgO < 50 nm particle size (BET) Sigma Aldrich), phosphoric acid (H₃PO₄ - 85 wt.% in H₂O, 99.99% trace metals basis - Sigma Aldrich). In order to determine the quantities of raw materials, calculations were performed to obtain HAp with Ca/P ratio of 1.5.

Keywords: bone regeneration, magnesium substitution, tricalcium phosphate, tissue engineering

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Authors: Giorgio Visentin, Inna S. Kalinina, Alexei A. Buchachenko

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In the ambit of intermolecular interactions, a combination rule is defined as a relation linking a potential parameter for the interaction of two unlike species with the same parameters for interaction pairs of like species. Some of their most exemplificative applications cover the construction of molecular dynamics force fields and dispersion-corrected density functionals. Here, an extended combination rule is proposed, relating the dipole-dipole dispersion coefficients for the interaction of like target species to the same coefficients for the interaction of the target and a set of partner species. The rule can be devised in two different ways, either by uniform discretization of the Casimir-Polder integral on a Gauss-Legendre quadrature or by relating the dynamic polarizabilities of the target and the partner species. Both methods return the same system of linear equations, which requires the knowledge of the dispersion coefficients for interaction between the partner species to be solved. The test examples show a high accuracy for dispersion coefficients (better than 1% in the pristine test for the interaction of Yb atom with rare gases and alkaline-earth metal atoms). In contrast, the rule does not ensure correct monotonic behavior of the dynamic polarizability of the target species. Acknowledgment: The work is supported by Russian Science Foundation grant # 17-13-01466.

Keywords: combination rule, dipole-dipole dispersion coefficient, Casimir-Polder integral, Gauss-Legendre quadrature

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Authors: Mohammad Borhani, Afshin Danehkar

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With the increase in population and the upward trend of energy demand, mankind has thought of using suppliers that guarantee a stable supply of energy, unlike fossil fuels, which, in addition to the widespread emission of greenhouse gases that one of the main factors in the destruction of the ozone layer and it will be finished in a short time in the not-so-distant future. In this regard, one of the sustainable ways of energy supply is the use of wind converters. That convert wind energy into electricity. For this reason, this research focused on wind turbines and their installation conditions. The main classification of wind turbines is based on the axis of rotation, which is divided into two groups: horizontal axis and vertical axis; each of these two types, with the advancement of technology in man-made environments such as cities, villages, airports, and other human environments can be installed and operated. The main difference between offshore and onshore wind turbines is their installation and foundation. Which are usually divided into five types; including of Monopile Wind Turbines, Jacket Wind Turbines, Tripile Wind Turbines, Gravity-Based Wind Turbines, and Floating Offshore Wind Turbines. For installation in a wind power plant requires an arrangement that produces electric power, the distance between the turbines is usually between 5 or 7 times the diameter of the rotor and if perpendicular to the wind direction be If they are 3 to 5 times the diameter of the rotor, they will be more efficient.

Keywords: wind farms, Savonius, Darrieus, offshore wind turbine, renewable energy

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Authors: Zohreh Khojasteh-Ghamari, Takashi Irohara

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One of the efficient ways in supply chain risk management is avoiding the interruption in Supply Chain (SC) before it occurs. Although the majority of the organizations focus on their first-tier suppliers to avoid risk in the SC, studies show that in only 60 percent of the disruption cases the reason is first tier suppliers. In the 40 percent of the SC disruptions, the reason is downstream SC, which is the second tier and lower. Due to the increasing complexity and interrelation of modern supply chains, the SC elements have become difficult to trace. Moreover, studies show that there is a vital need to better understand the integration of risk and visibility, especially in the context of multiple objectives. In this study, we propose a multi-objective programming model to avoid disruption in SC. The objective of this study is evaluating the effect of downstream SCV on managing supply chain risk. We propose a multi-objective mathematical programming model with the objective functions of minimizing the total cost and maximizing the downstream supply chain visibility (SCV). The decision variable is supplier selection. We assume there are several manufacturers and several candidate suppliers. For each manufacturer, our model proposes the best suppliers with the lowest cost and maximum visibility in downstream supply chain. We examine the applicability of the model by numerical examples. We also define several scenarios for datasets and observe the tendency. The results show that minimum visibility in downstream SC is needed to have a safe SC network.

Keywords: downstream supply chain, optimization, supply chain risk, supply chain visibility

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Authors: Iyasu Eibedingil

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The construction industry is one of the major factors responsible for causing a negative impact on the environment. It has the largest share in the use of natural resources including land use, material extraction, and greenhouse gases emissions. For this reason, it is imperative to reduce its environmental impact through the construction of sustainable buildings with less impact. These days, it is possible to measure the environmental impact by using different tools such as the life cycle assessment (LCA) approach. Given this premise, this study explored the environmental impact of two types of roofing systems through comparative life cycle assessment approach. The tiles were analyzed to select the most environmentally friendly roofing system for the villa at Khalifa City A, Abu Dhabi, United Arab Emirates. These products are available in various forms; however, in this study concrete roof tiles and clay roof tiles were considered. The results showed that concrete roof tiles have lower environmental impact. In all scenarios considered, manufacturing the roof tiles locally, using recovered fuels for firing clay tiles, and using renewable energy (electricity from PV plant) showed that the concrete roof tiles were found to be excellent in terms of its embodied carbon, embodied the energy and various other environmental performance indicators.

Keywords: clay roof tile, concrete roof tile, life cycle assessment, sensitivity analysis

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Authors: Apu Kumar Saha, Mrinmoy Majumder

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The increase in the concentration of Green House gases all over the World has induced global warming phenomena whereby the average temperature of the world has aggravated to impact the pattern of climate in different regions. The frequency of extreme event has increased, early onset of season and change in an average amount of rainfall all are engrossing the conclusion that normal pattern of climate is changing. Sophisticated and complex models are prepared to estimate the future situation of the climate in different zones of the Earth. As hydro-energy is directly related to climatic parameters like rainfall and evaporation such energy resources will have to sustain the onset of the climatic abnormalities. The present investigation has tried to assess the impact of climatic abnormalities upon hydropower potential of different regions of the World. In this regard multi-criteria, decision making, and the neural network is used to predict the impact of the change cognitively by an index. The results from the study show that hydro-energy potential of Asian region is mostly vulnerable with respect to other regions of the world. The model results also encourage further application of the index to analyze the impact of climate change on the potential of hydro-energy.

Keywords: hydro-energy potential, neural networks, multi criteria decision analysis, environmental and ecological engineering

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Authors: Omar M. Elmabrouk., Roaa Y. Taha., Najat M. Ebrahim, Sabbreen A. Mohammed

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Power transformers are the most crucial part of power electrical system, distribution and transmission grid. This part is maintained using predictive or condition-based maintenance approach. The diagnosis of power transformer condition is performed based on Dissolved Gas Analysis (DGA). There are five main methods utilized for analyzing these gases. These methods are International Electrotechnical Commission (IEC) gas ratio, Key Gas, Roger gas ratio, Doernenburg, and Duval Triangle. Moreover, due to the importance of the transformers, there is a need for an accurate technique to diagnose and hence predict the transformer condition. The main objective of this technique is to avoid the transformer faults and hence to maintain the power electrical system, distribution and transmission grid. In this paper, the DGA was utilized based on the data collected from the transformer records available in the General Electricity Company of Libya (GECOL) which is located in Benghazi-Libya. The Fuzzy Logic (FL) technique was implemented as a diagnostic approach based on IEC gas ratio method. The FL technique gave better results and approved to be used as an accurate prediction technique for power transformer faults. Also, this technique is approved to be a quite interesting for the readers and the concern researchers in the area of FL mathematics and power transformer.

Keywords: dissolved gas-in-oil analysis, fuzzy logic, power transformer, prediction

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Authors: Andrii Biloshchytskyi, Serik Omirbayev, Alexandr Neftissov, Sapar Toxanov, Svitlana Biloshchytska, Adil Faizullin

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Kazakhstan has adopted a carbon neutrality strategy until 2060. In accordance with this strategy, it is necessary to introduce various tools to maintain the environmental safety of the environment. The use of IoT, in combination with the characteristics and requirements of Kazakhstan's environmental legislation, makes it possible to develop a modern environmental monitoring system. The article proposes a solution for developing an example of an automated system for the continuous collection of data on the concentration of pollutants in the atmosphere based on an open architecture. The Audino-based device acts as a microcontroller. It should be noted that the transmission of measured values is carried out via an open wireless communication protocol. The architecture of the system, which was used to build a prototype based on sensors, an Arduino microcontroller, and a wireless data transmission module, is presented. The selection of elementary components may change depending on the requirements of the system; the introduction of new units is limited by the number of ports. The openness of solutions allows you to change the configuration depending on the conditions. The advantages of the solutions are openness, low cost, versatility and mobility. However, there is no comparison of the working processes of the proposed solution with traditional ones.

Keywords: environmental monitoring, greenhouse gases emissions, environmental pollution, Industry 4.0, IoT, microcontroller, automated monitoring system.

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Authors: Junjie Liu, David Selby, Mark Obermajer, Andy Mort

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The inaugural application of Re-Os dating, which is based on the beta decay of 187Re to 187Os with a long half-life of 41.577 ± 0.12 Byr and initially used for sulphide minerals and organic rich rocks, to petroleum systems was performed on bitumen of the Polaris Mississippi Valley Type Pb-Zn deposit, Canada. To further our understanding of the Re-Os system and its application to petroleum systems, here we present a study on Duvernay Petroleum System, Western Canadian Sedimentary Basin. The Late Devonian Duvernay Formation organic-rich shales are the only source of the petroleum system. The Duvernay shales reached maturation only during the Laramide Orogeny (80 – 35 Ma) and the generated oil migrated short distances into the interfingering Leduc reefs and overlying Nisku carbonates with no or little secondary alteration post oil-generation. Although very low in Re and Os, the asphaltenes of Duvernay-sourced Leduc and Nisku oils define a Laramide Re-Os age. In addition, the initial Os isotope compositions of the oil samples are similar to that of the Os isotope composition of the Duvernay Formation at the time of oil generation, but are very different to other oil-prone intervals of the basin, showing the ability of the Os isotope composition as an inorganic oil-source correlation tool. In summary, the ability of the Re-Os geochronometer to record the timing of oil generation and trace the source of an oil is confirmed in the Re-Os study of Duvernay Petroleum System.

Keywords: Duvernay petroleum system, oil generation, oil-source correlation, Re-Os

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Authors: Georgii Emelianov, Mikhail Polikarpov, Fabian Hübner, Jochen Deuse, Jochen Schiemann

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Recycling refrigerating appliances plays a major role in protecting the Earth's atmosphere from ozone depletion and emissions of greenhouse gases. The performance of refrigerator recycling plants in terms of material retention is the subject of strict environmental certifications and is reviewed periodically through specialized audits. The continuous collection of Refrigerator data required for the input-output analysis is still mostly manual, error-prone, and not digitalized. In this paper, we propose an automated data collection system for recycling plants in order to deduce expected material contents in individual end-of-life refrigerating appliances. The system utilizes laser scanner measurements and optical data to extract attributes of individual refrigerators by applying transfer learning with pre-trained vision models and optical character recognition. Based on Recognized features, the system automatically provides material categories and target values of contained material masses, especially foaming and cooling agents. The presented data collection system paves the way for continuous performance monitoring and efficient control of refrigerator recycling plants.

Keywords: automation, data collection, performance monitoring, recycling, refrigerators

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Authors: Wenjun Zhang, Yunqing Du, Steven W. Cranford, Ming L. Wang

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The beginning of 21st century has witnessed new advancements in the design and use of new materials for biosensing applications, from nano to macro, protein to tissue. Traditional analytical methods lack a complete toolset to describe the complexities introduced by living systems, pathological relations, discrete hierarchical materials, cross-phase interactions, and structure-property dependencies. Materiomics – via systematic molecular dynamics (MD) simulation – can provide structure-process-property relations by using a materials science approach linking mechanisms across scales and enables oriented biosensor design. With this approach, DNA biosensors can be utilized to detect disease biomarkers present in individuals’ breath such as acetone for diabetes. Our wireless sensor array based on single-stranded DNA (ssDNA)-decorated single-walled carbon nanotubes (SWNT) has successfully detected trace amount of various chemicals in vapor differentiated by pattern recognition. Here, we present how MD simulation can revolutionize the way of design and screening of DNA aptamers for targeting biomarkers related to oral diseases and oral health monitoring. It demonstrates great potential to be utilized to build a library of DNDA sequences for reliable detection of several biomarkers of one specific disease, and as well provides a new methodology of creating, designing, and applying of biosensors.

Keywords: biosensor, DNA, biomarker, molecular dynamics simulation

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Authors: Hossam El-Sayed Emam

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As an essential issue for life, water while it’s important for all living organisms. However, the world is dangerously facing the serious problem for the deficiency of the sources of drinking water. Within the aquatic systems, there are various gases, microbes, and other toxic ingredients (chemical compounds and heavy metals) occurred owing to the draining of agricultural and industrial wastewater, resulting in water pollution. On the other hand, fuel (gaseous, liquid, or in solid phase) is one of the extensively consumable energy sources, and owing to its origin from fossil, it contains some sulfur-, nitrogen- and oxygen-based compounds that cause serious problems (toxicity, catalyst poisoning, corrosion, and gum formation andcarcinogenic effects), to be ascribed as undesirable pollutants.MOFs as porous coordinating polymers are superiorly exploited in the adsorption and separationof contaminants for wastewater treatment and fuel purification. The inclusion of highly adsorbent materials like MOFs to be immobilized within cellulosic materialscould be investigated as a new challenge for the separation of contaminants with high efficiency and opportunity for recyclability. Therefore, the current approach ascribes the exploitation of different MOFsimmobilized within cellulose (powder, films, and fabrics)for applications in environmental. Herein, using cellulose containing MOFs in dye removal (degradation and adsorption), pharmaceutical intermediates removal, and fuel purification were summarized.

Keywords: cellulose, MOFs, dye removal, pharmaceutical intermediates, fuel purification

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Authors: Durata Haciu, Elif Sena Tekin, Gokce Ozturk, Patricia Ramey Balcı

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Coastal zones are under increasing threat due to anthropogenic activities that introduce considerable pollutants such as heavy metals into marine ecosystems. As part of a larger experimental study examining species responses to contaminated marine sediments, surface sediments (top 5cm) were analysed for major trace elements at three locations in Istanbul Straight. Samples were randomly collected by divers (May 2018) using hand-corers from Istinye (n=4), Garipce (n=10) and Poyrazköy (n=6), at water depths of 4-8m. Twelve metals were examined: As, arsenic; Pb, lead; Cd, cadmium; Cr, chromium; Cu, Copper; Fe, Iron; Ni, Nickel; Zn, Zinc; V, vanadium; Mn, Manganese; Ba, Barium; and Ag, silver by wavelength-dispersive X-ray fluorescence spectrometry (WDXRF) and Inductively Coupled Plasma/Mass Spectroscopy (ICP/MS). Preliminary results indicate that the average concentrations of metals (mg kg⁻¹) varied considerably among locations. In general, concentrations were relatively lower at Garipce compared to either Istinye or Poyrazköy. For most metals mean concentrations were highest at Poyrazköy and Ag and Cd were below detection limits (exception= Ag in a few samples). While Cd and As were undetected in all stations, the concentrations of Fe and Ni fall in the criteria of moderately polluted range and the rest of the metals in the range of low polluted range as compared to Effects Range Low (ERL) and Effects Range median (ERM) values determined by US Environmental Protection Agency (EPA).

Keywords: effect-range classification, ICP/MS, marine sediments, XRF

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Authors: Ben Yahia Nouha, Harris Chris, Sebei Abdelaziz, Boussen Slim, Chaabani Fredj

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The present work has set itself the objective of studying non-detritic siliceous rocks of the extreme northwest Tunisia. It aims to examine the origin and their sedimentary depositional environment based on mineralogical and geochemical characteristics. The different sections were located in the area of Babouch and the area of Tabarka. The collected samples were subjected to mineralogical and geochemical characterization using different analytical methods: X-ray diffraction (XRD), geochemical analysis (ICP- AES), isotopic geochemistry (δ18O), to assess their suitability for industrial use. X-ray powder diffraction of the pure siliceous rock indicates quartz as the major mineral, with the total lack of amorphous silica. Trace impurities, such as carbonate and clay minerals, are concealed in the analytical results. The petrographic examination revealed allowed us to deduce that this rock was deriving from tests of siliceous organisms (the radiolarians). The chemical composition shows that SiO2, Al2O3, and Fe2O3 represent the most abundant oxides. The other oxides are present in negligible quantities. Geochemical data support a biogenic and non-hydrothermal origin of babouchite silica. Oxygen isotopic has shown that babouchites were formed in an environment with a high temperature ranging from 56 °C to 73 °C.

Keywords: biogenic silica, babouchite formation, XRD, chemical analysis, oxygen isotopic, northwest tunisia

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Authors: Davide Palma, Dimitra Papagiannaki, Marco Minella, Manuel Lai, Rita Binetti, Claire Richard

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Modern analytical technologies allow us to detect water contaminants at trace and ultra-trace concentrations highlighting how a large number of organic compounds is not efficiently abated by most wastewater treatment facilities relying on biological processes; we usually refer to these micropollutants as contaminants of emerging concern (CECs). The availability of reliable end effective technologies, able to guarantee the high standards of water quality demanded by legislators worldwide, has therefore become a primary need. In this context, water plasma stands out among developing technologies as it is extremely effective in the abatement of numerous classes of pollutants, cost-effective, and environmentally friendly. In this work, a custom-built non-thermal pulsed plasma discharge generator was used to abate the concentration of selected CECs in the water samples. Samples were treated in a 50 mL pyrex reactor using two different types of plasma discharge occurring at the surface of the treated solution or, underwater, working with positive polarity. The distance between the tips of the electrodes determined where the discharge was formed: underwater when the distance was < 2mm, at the water surface when the distance was > 2 mm. Peak voltage was in the 100-130kV range with typical current values of 20-40 A. The duration of the pulse was 500 ns, and the frequency of discharge could be manually set between 5 and 45 Hz. Treatment of 100 µM diclofenac solution in MilliQ water, with a pulse frequency of 17Hz, revealed that surface discharge was more efficient in the degradation of diclofenac that was no longer detectable after 6 minutes of treatment. Over 30 minutes were required to obtain the same results with underwater discharge. These results are justified by the higher rate of H₂O₂ formation (21.80 µmolL⁻¹min⁻¹ for surface discharge against 1.20 µmolL⁻¹min⁻¹ for underwater discharge), larger discharge volume and UV light emission, high rate of ozone and NOx production (up to 800 and 1400 ppb respectively) observed when working with surface discharge. Then, the surface discharge was used for the treatment of the three selected perfluoroalkyl compounds, namely, perfluorooctanoic acid (PFOA), perfluorohexanoic acid (PFHxA), and pefluorooctanesulfonic acid (PFOS) both individually and in mixture, in ultrapure and groundwater matrices with initial concentration of 1 ppb. In both matrices, PFOS exhibited the best degradation reaching complete removal after 30 min of treatment (degradation rate 0.107 min⁻¹ in ultrapure water and 0.0633 min⁻¹ in groundwater), while the degradation rate of PFOA and PFHxA was slower of around 65% and 80%, respectively. Total nitrogen (TN) measurements revealed levels up to 45 mgL⁻¹h⁻¹ in water samples treated with surface discharge, while, in analogous samples treated with underwater discharge, TN increase was 5 to 10 times lower. These results can be explained by the significant NOx concentrations (over 1400 ppb) measured above functioning reactor operating with superficial discharge; rapid NOx hydrolysis led to nitrates accumulation in the solution explaining the observed evolution of TN values. Ionic chromatography measures confirmed that the vast majority of TN was under the form of nitrates. In conclusion, non-thermal pulsed plasma discharge, obtained with a custom-built generator, was proven to effectively degrade diclofenac in water matrices confirming the potential interest of this technology for wastewater treatment. The surface discharge was proven to be more effective in CECs removal due to the high rate of formation of H₂O₂, ozone, reactive radical species, and strong UV light emission. Furthermore, nitrates enriched water obtained after treatment could be an interesting added-value product to be used as fertilizer in agriculture. Acknowledgment: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 765860.

Keywords: CECs removal, nitrogen fixation, non-thermal plasma, water treatment

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Authors: Joshua N. Edokpayi, John O. Odiyo, Patience P. Shikwambana

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Water is a very rare natural resource in South Africa. Ga-Selati River is used for both domestic and industrial purposes. This study was carried out in order to assess the quality of Ga-Selati River in a mining area of Limpopo Province-Phalaborwa. The pH, Electrical Conductivity (EC) and Total Dissolved Solids (TDS) were determined using a Crinson multimeter while turbidity was measured using a Labcon Turbidimeter. The concentrations of Al, Ca, Cd, Cr, Fe, K, Mg, Mn, Na and Pb were analysed in triplicate using a Varian 520 flame atomic absorption spectrometer (AAS) supplied by PerkinElmer, after acid digestion with nitric acid in a fume cupboard. The average pH of the river from eight different sampling sites was 8.00 and 9.38 in wet and dry season respectively. Higher EC values were determined in the dry season (138.7 mS/m) than in the wet season (96.93 mS/m). Similarly, TDS values were higher in dry (929.29 mg/L) than in the wet season (640.72 mg/L) season. These values exceeded the recommended guideline of South Africa Department of Water Affairs and Forestry (DWAF) for domestic water use (70 mS/m) and that of the World Health Organization (WHO) (600 mS/m), respectively. Turbidity varied between 1.78-5.20 and 0.95-2.37 NTU in both wet and dry seasons. Total hardness of 312.50 mg/L and 297.75 mg/L as the concentration of CaCO3 was computed for the river in both the wet and the dry seasons and the river water was categorised as very hard. Mean concentration of the metals studied in both the wet and the dry seasons are: Na (94.06 mg/L and 196.3 mg/L), K (11.79 mg/L and 13.62 mg/L), Ca (45.60 mg/L and 41.30 mg/L), Mg (48.41 mg/L and 44.71 mg/L), Al (0.31 mg/L and 0.38 mg/L), Cd (0.01 mg/L and 0.01 mg/L), Cr (0.02 mg/L and 0.09 mg/L), Pb (0.05 mg/L and 0.06 mg/L), Mn (0.31 mg/L and 0.11 mg/L) and Fe (0.76 mg/L and 0.69 mg/L). Results from this study reveal that most of the metals were present in concentrations higher than the recommended guidelines of DWAF and WHO for domestic use and the protection of aquatic life.

Keywords: contamination, mining activities, surface water, trace metals

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Authors: Rini Rahul, Manoj Kumar

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Cadmium (Cd) is a poisonous trace metal, which is responsible for excess reactive oxygen species generation (ROS) in plants, thereby adversely affecting their productivity and commercial potential. Ricinus communis (castor) is an industry-efficient non-edible bioenergy crop used for phytoremediation and re-vegetation. We have determined the total Cd content in castor genotypes and established a relationship between the Cd tolerance mechanism and physiological parameters like chlorophyll fluorescence, the total photosynthetic activity, chlorophyll and carotenoid content as well as ROS generation and malondialdehyde content. This study is an effort to comprehend the interrelation between Cd toxicity (control, 250 µM and 500 µM), proline, various ROS scavenging enzymes (anti-oxidative in nature), nicotianamine synthase (NAS) and Natural resistance-associated macrophage protein (NRAMP) gene. The antioxidant enzyme activity increased for WM hence conferring Cd toxicity in this genotype. RcNRAMP genes showed differential expression in GCH2 and WM genotypes; this can also be one of the reasons for Cd toxicity and sensitivity in WM and GCH2, respectively. The cause of pronounced Cd tolerance in WM leaves can be because of enhanced expression of RcNAS1, RcNAS2 and RcNAS3 genes. Our results demonstrate that there is an interrelation between Cd toxicity (control, 250 µM and 500 µM), proline, various ROS scavenging enzymes (anti-oxidative in nature), NAS and NRAMP gene.

Keywords: ricinus communis, cadmium, reactive oxygen species, nicotianamine synthase, NRAMP, malondialdehyde

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Authors: Suchismita Dattagupta

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Social rules and guidelines specify how a body should be clothed and how it should look. The social rules have made the body a space for expression, oppression and sexual 'commodification'. Being a malleable aspect of the human body, hair has always been worn in a number of ways and this characteristic of hair has made it an essential vehicle for conveying symbolic meaning. Hair, particularly women’s hair has always been considered to be associated with richness and beauty, apart from being associated with sexual power. Society has always had a preoccupation with hair bordering on obsession and has projected its moral and political supremacy by controlling and influencing how an individual wears their hair. Irrespective of the gender of the individual, society has tried to control an individual’s hair to express its control. However, with time, there has been a marked change in the way hair has been used by the individual. Hair has always been the focus of scholarly studies; not just aesthetically, but also in the cultural and social context. The fascination with hair rises from the fact that it is the only part of the human body that is always on display. Fetishization of hair is common in literature and goes ahead to reveal the character’s social and moral status. Modern authors for children and young adults have turned this concept on its head to point out how characters are breaking away from the mould and establishing their personal, moral and social boundaries. This paper will trace the change in hair symbolism in literature for children and young adults to understand how it has changed over the course of the time and what light it throws on the changing pattern of women’s position in society.

Keywords: gender, hair, social symbols, society, women's role

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Authors: L. R. Shobin, S. Manivannan

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One dimensional silver nanowires and nanoparticles gained more interest in developing transparent conducting films, catalysis, biological and chemical sensors. Silver nanostructures can be synthesized by varying reaction conditions such as the precursor concentration, molar ratio of the surfactant, injection speed of silver ions, etc. in the polyol process. However, the reaction proceeds for greater than 2 hours for the formation of silver nanowires. The introduction of etchant in the medium promotes the growth of silver nanowires from silver nanoparticles along the [100] direction. Rapid growth of silver nanowires is accomplished using the Cl- ions from NaCl and polyvinyl pyrrolidone (PVP) as surfactant. The role of Cl- ion was investigated in the growth of the nanostructured silver. Silver nanoparticles (<100 nm) were harvested from glycerol medium in the absence of Cl- ions. Trace amount of Cl- ions (2.5 mM -NaCl) produced the edge joined nanowires of length upto 2 μm and width ranging from 40 to 65 nm. Formation and rapid growth (within 25 minutes) of long, uniform silver nanowires (upto 5 μm) with good yield were realized in the presence of 5 mM NaCl at 200ºC. The growth of nanostructures was monitored by UV-vis-NIR spectroscopy. Scanning and transmission electron microscopes reveal the morphology of the silver nano harvests. The role of temperature in the reduction of silver ions, growth mechanism for nanoparticles, edge joined and straight nanowires will be discussed.

Keywords: silver nanowires, glycerol mediated polyol process, scanning electron microscopy, UV-Vis- NIR spectroscopy, transmission electron microscopy

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Authors: D. Chen, H. Daoud, C. Kreiner, U. Glatzel

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Additive Manufacturing (AM) provides promising opportunities to optimize and to produce tooling by integrating near-contour tempering channels for more efficient cooling. To enhance the properties of the produced tooling using additive manufacturing, prototypes should be produced in short periods. Thereby, this requires a small amount of tailored powders, which either has a high production cost or is commercially unavailable. Hence, in this study, an arc spray atomization approach to produce a tailored metal powder at a lower cost and even in small quantities, in comparison to the conventional powder production methods, was proposed. This approach involves converting commercially available metal wire into powder by modifying the wire arc spraying process. The influences of spray medium and gas pressure on the powder properties were investigated. As a result, particles with smooth surface and lower porosity were obtained, when nonoxidizing gases are used for thermal spraying. The particle size decreased with increasing of the gas pressure, and the particles sizes are in the range from 10 to 70 µm, which is desirable for selective laser melting (SLM). A comparison of microstructure and mechanical behavior of SLM generated parts using arc sprayed powders (alloy: X5CrNiCuNb 16-4) and commercial powder (alloy: X5CrNiCuNb 16-4) was also conducted.

Keywords: additive manufacturing, arc spraying, powder production, selective laser melting

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Authors: K. R. Padma, K. R. Don

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Background and aims: A balanced nutritional diet is essential in maintaining immunity and for deterrence as well as desisting of viral infections. Nevertheless, currently, very less information is available online regarding nutrition consumption during the period of coronavirus infection, i.e. (COVID-19). In our systematic review article, we portrayed and aimed to evaluate evidence from various previous clinical trials, which was based on nutritional interventions for viral diseases and given a concise overview. Methods: A systematic search was carried out employing 3 key medical databases: PubMed®, Web of Science®, and SciVerse Scopus®. Studies were performed and evaluated suitable if clinical trials in humans, appropriate immunological parameters on viral and respiratory infections, need to perform. Basic Clinical trials on nutritional vitamins, minerals, nutraceuticals as well as probiotics were included. Results: We have explored 10 review articles and extracted data for our study. A total of > 2000 participants were included and excluded several other trace elements as well as various vitamins, but in inclusion criteria mainly concentrated on those who have shown propitious immune-modulatory effects against viral respiratory infections. Conclusions: We have encapsulated the potential health benefits of some minerals, vitamins, as well as certain designer foods, nutraceuticals, and probiotics in viral infections. Based on this nutritional interventional strategy available from our present data, it could be promising to abstain and reduce the COVID-19 infection replication and boost our immunity to fight against the virus.

Keywords: COVID-19, immunity, vitamins, nutritional intervention strategy

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Authors: Maha Mohamed Hady Ali, M. A. El-Sayed

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Camel (Camelus dromedarius) is very important animal in many arid and semi-arid zones of tropical and subtropical regions as it serves as dual purpose providing meat and milk for human and as draft animal. Camel, like other animal must receive all essential nutrients despite the hostile environment. A study was conducted to evaluate the nutritional status of some micro-minerals of camel under Egyptian environmental condition. Forty five blood samples were collected from apparently healthy male camels with an average age between 2-6 years at the slaughter house in Cairo province, Egypt. The animals were fed mainly on berseem (Trifolium alexandrinum) or concentrate with straw before slaughtering. The collected serum and feedstuff samples were subjected to copper, iron, selenium and zinc analysis using Atomic absorption spectrophotometer. The data showed variation in the level of copper, iron, selenium and zinc in the serum of the dromedary camel as well as in the feedstuffs. Furthermore, the results indicated that the micro- minerals status of feeds may not always reflected as such in camel blood suggesting some role of bioavailability. The main reason for the lack of such reflection seems to be the wide diversity exists in the surrounding environment (forages and plants) as well as the bioavailability of such minerals. Since the requirement of micro-minerals have not been established for camel, more researches must be focused on this topic.

Keywords: camel, copper, egypt, feed stuff, iron, selenium, zinc

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Authors: Sinem Bagce, Ensar Yilmaz

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As a well-known fact, neoclassical economics excludes 'what is humanized' out of the literature for a long time. Rationality is defined in a very narrow context in the mainstream economics. Identity economics is one of the challenges raised against this tradition. The concept of 'identity' has been introduced to economics by Akerlof and Kranton (2000). The identity-based analysis mainly searches the links between economic welfare and decision of the actors in question related to ethnic, racial, gender and immigrant issues. This is more about discrimination and its repercussions on economic decisions of the relevant actors in a social sphere. In this article, we, in the context of identity economics, search the economic welfare and decisions of Romani people in Turkey. It is plainly observed that identity is clearly the major determinant for Romani people in economic and social life. They have their own distinctive rationality in making economic decisions. For a more scrutinized and academic analysis, we aim to trace their economic identity in their real social environment. This study is an extension of surveys conducted on Romani people in Turkey. Using data similar to SILC (Statistics for Income and Living Conditions) conducted on Romani people across the whole Turkey, we look for some questions about the income/welfare distribution among them, consumer preferences/habits, living conditions, occupations, education and as such. For this, by employing econometric and statistical analytical tools, we aim to obtain the answers for these questions. We think these analytic results will provide us to evaluate the links between their economic state and their identity more thoroughly. JEL Codes: D1, J 15, R23.

Keywords: identity economics, Romani people, discrimination, social identity and preferences

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Authors: Glemarie C. Hermosa, Sheng-Jie You, Chien Chih Hu

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Efficient separation technologies are required for the removal of carbon dioxide from natural gas streams. Membrane-based natural gas separation has emerged as one of the fastest growing technologies, due to the compactness, higher energy efficiency and economic advantages which can be reaped. The removal of Carbon dioxide from gas streams using membrane technology will also give the advantage like environmental friendly process compared to the other technologies used in gas separation. In this study, Polyimide membranes, which are mostly used in the separation of gases, are blended with a new kind of solvent: Deep Eutectic Solvents or simply DES. The three types of DES are used are choline chloride based mixed with three different hydrogen bond donors: Lactic acid, N-methylurea and Urea. The blending of the DESs to Polyimide gave out high permeability performance. The Gas Separation performance for all the membranes involving CO2/CH4 showed low performance while for CO2/N2 surpassed the performance of some studies. Among the three types of DES used the solvent Choline Chloride/Lactic acid exhibited the highest performance for both Gas Separation applications. The values are 10.5 for CO2/CH4 selectivity and 60.5 for CO2/N2. The separation results for CO2/CH4 may be due to the viscosity of the DESs affecting the morphology of the fabricated membrane thus also impacts the performance. DES/blended Polyimide membranes fabricated are novel and have the potential of a low-cost and environmental friendly application for gas separation.

Keywords: deep eutectic solvents, gas separation, polyimide blends, polyimide membranes

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Authors: Umme Shahera, Saifullah Munshi, Munira Jahan, Afzalun Nessa, Shahinul Alam, Shahina Tabassum

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The development of HCC is a multi-stage process. Several extrinsic factors, such as aflatoxin, HBV, nutrition, alcohol, and trace elements are thought to initiate or/and promote the hepatocarcinogenesis. Alteration of p53 status is an important intrinsic factor in this process as p53 is essential for preventing inappropriate cell proliferation and maintaining genome integrity following genotoxic stress. This study was designed to assess the correlation of p53 gene expression with HBV-DNA and serum Alanine transaminase (ALT) in patients with cirrhosis and HCC. The study was conducted among 60 patients. The study population were divided into four groups (15 in each groups)-HBV positive cirrhosis, HBV negative cirrhosis, HBV positive HCC and HBV negative HCC. Expression of p53 gene was observed using real time PCR. P53 gene expressions in the above mentioned groups were correlated with serum ALT level and HBV viral load. p53 gene was significantly higher in HBV-positive patients with HCC than HBV-positive cirrhosis. Similarly, the expression of p53 was significantly higher in HBV-positive HCC than HBV-negative HCC patients. However, the expression of p53 was reduced in HBV-positive cirrhosis in comparison with HBV-negative cirrhosis. P53 gene expression in liver was not correlated with the serum levels of ALT in any of the study groups. HBV- DNA load also did not correlated with p53 gene expression in HBV positive HCC and HBV positive cirrhosis patients. This study shows that there was no significant change with the expression of p53 gene in any of the study groups with ALT level or viral load, though differential expression of p53 gene were observed in cirrhosis and HCC patients.

Keywords: P53, ALT, HBV-DNA, liver cirrhosis, hepatocellular carcinoma

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Authors: Pius Akindele Adeniyi

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Developing countries including Nigeria are greatly saddled with problems emanating from environmental deterioration. These problems are glaringly threatening the existence of mankind. A wide range of factors contribute to environmental problems and prominent among these are: increase in human population, deforestation, industrialization, urbanization, ignorance and socio-economic activities. The economic function of the forest has for quite a long time played a major role in the economic life of the people of Nigeria while the social function such as the recreational use of the forest has until today play very little role in the cultural development of the country. Recreation forest ameliorates the environment, reduces psychological stress, and broadens individual outlook and horizon. Unfortunately domestic tourism of recreational forest is not developed and almost unknown due to poverty and non existence of recreational facilities. Social forestry is seen as a sustainable means of combating ecological problems especially in third world countries such as Nigeria. The programme also provides social and economic benefits to the rural people. As a rural-based activity, people's participation is crucial for its success. There is need to create awareness on recreational forestry and social forestry as well as harness their resources for the country .This paper therefore highlights the constraints in the practice of social and recreational forestry in developing countries and suggests ways to motivate the rural people to participate in the programme. . Attempt has been made to trace the causes and consequences of Nigerian environmental deterioration, while suggestions on possible solutions are proffered .

Keywords: recreational, social, deteriorating, forestry

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Authors: I. T. Asowata, A. S. Akinwumiju

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The enrichment of potentially harmful elements (PHEs) in stream sediments (SS) and floodplain soils (FS) poses great environmental hazards to water bodies and other parts of the ecosystem. The aim of this research was to assess the distribution pattern of selected PHEs (Cu, Pb, Zn, Co, Mn, As, Cd, V, Cr, Ni, Th, Sr, and La) in SS of selected rivers that drain Ile-Ife area and their adjacent FS, to ascertain the pollution status of these elements in the study area. 60 samples (40 SS and 20 FS) were purposely collected for this study; the samples were air-dried at room temperature, disaggregated, sieved with > 63 µm and digested with modified aqua reqia (1:1:1 HCl:HNO₃:H₂O) and were analysed with ultra-trace inductively coupled plasma mass spectrometry method (ICP-ES). The geochemical results showed decreasing trend of average contents of PHEs studied Mn > Zn > V > Cr > Pb > La > Sr > Cu > Ni > Co > Th > As > Cd for both SS and FS. Floodplain topsoil in ppm, Cu range from 10.0-180.0; mean, 71.1, Pb, 17.1-255.0; 93.5 and Zn, 83.0-3122.2; 826.0. Also, floodplain sub-soils, Cu range from 30.0-203.1; mean of 76.6, Pb, 16.0-214.0; 77.9 and Zn, 59.1-2351.0; 622.3. Similarly, SS results for Cu, 22.1-257.0; 70.3, Pb, 15.0-172.0; 67.3 and Zn, 65.0-1285.0; 357.8, among other PHEs, suggesting significant level of PHEs enrichment in the studied geo media. Elemental association showed positive and/or negative correlation among the PHEs and also showed different sources of metal enrichment to be largely anthropogenic with some geogenic. Geoaccumulation and metal ratio indexes indicated that FS and SS studied have received significant PHEs of between moderately to strongly polluted, which implies significant environmental implications in the study area.

Keywords: aqua regia, enrichment, GIS, Ile-Ife, potentially harmful elements

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Authors: Guangtong Xu, Yi He

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Like most historic and cultural cities in China, the historic urban area of Jingmen city is facing a typical spatial problem of fragmentation and fuzzification. This study focuses on exploring a method for evaluating the existing values of historic urban area based on spatial prototype, a concept introduced into urban morphology from 'Archetype' in architectural typology. As the spatial elements and built-up relationship of historic city, spatial prototype has habitual structural characteristics and formal modulus. It is the inherent logic and order rules behind the scattered historic environment, providing a clue to understand the spatial characteristics and a basis for guiding the construction and conservation in historic urban areas. Three criteria, the resolution of historical elements, the completeness of historical structure and the renewal potential of associated land, were selected to construct the integrated assessment system. These three dimensions are linked to the spatial prototype and its constituent elements, as well as the transformation relationship in ancient and present day. The results showed that historic urban areas have changed from a holistic city to different existing types dominated by their historic structure elements. It is necessary to improve the pertinence of planning strategies and develop diversified management measures in the conservation scope of historic urban area. Moreover, a constructive-conservation strategy should be put forward to enhance the integrity of historic urban area based on the trace of spatial prototype and evaluation results.

Keywords: constructive conservation, existing value, historic urban area, spatial prototype

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Authors: H. Al-Baghli, F. Al-Asfour

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The current applied asphalt technology for Kuwait roads pavement infrastructure is the hot mix asphalt (HMA) pavement, including both pen grade and polymer modified bitumen (PMBs), that is produced and compacted at high temperature levels ranging from 150 to 180 °C. There are no current specifications for warm and cold mix asphalts in Kuwait’s Ministry of Public Works (MPW) asphalt standard and specifications. The process of the conventional HMA is energy intensive and directly responsible for the emission of greenhouse gases and other environmental hazards into the atmosphere leading to significant environmental impacts and raising health risk to labors at site. Warm mix asphalt (WMA) technology, a sustainable alternative preferred in multiple countries, has many environmental advantages because it requires lower production temperatures than HMA by 20 to 40 °C. The reduction of temperatures achieved by WMA originates from multiple technologies including foaming and chemical or organic additives that aim to reduce bitumen and improve mix workability. This paper presents a literature review of WMA technologies and techniques followed by an experimental study aiming to compare the results of produced WMA samples, using a water containing additive (foaming process), at different compaction temperatures with the HMA control volumetric properties mix designed in accordance to the new MPW’s specifications and guidelines.

Keywords: warm-mix asphalt, water-bearing additives, foaming-based process, chemical additives, organic additives

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