Search results for: hydrogen and nitrogen diffusion

Authors: Shirley Lamptey, Lingling Li, Junhong Xie

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Agriculture in the semi-arid is often challenged by overuse of N, inadequate soil water, and heavy carbon emissions thereby threatening sustainability. Field experiments were conducted to investigate the effect of nitrogen fertilization levels (0-N₀, 100-N₁₀₀, 200-N₂₀₀, and 300 kg ha⁻¹-N₃₀₀) on soil water dynamics, soil respiration (Rs), net ecosystem production (NEP), and biomass yield. Zero nitrogen soils decreased Rs by 23% and 16% compared to N₃₀₀ and N₂₀₀ soils, respectively. However, biomass yield was greatest under N₃₀₀ compared with N₀, which therefore translated into increased net primary production (NPP) by 89% and NEP by 101% compared to N₀. To a lesser extent, N₂₀₀ increased net primary production by 69% and net ecosystem production by 79% compared to N₀. Grain yields were greatest under N₃₀₀ compared with N₁₀₀ and N₀, which therefore translated into increased carbon emission efficiency (CEE) by 53%, 39% and 3% under N₃₀₀ compared to N₀, N₁₀₀, and N₂₀₀ treatments respectively. Under the conditions of this study, crop yield and CEE may be optimized at nitrogen application rates in the range of 200-300 kg ha⁻¹. Based on these results, there appears potential for 200 kg N ha⁻¹ to be used to improve yield and increase CEE in the context of the rainfall-limiting environment.

Keywords: carbon emission, carbon emission efficiency, C sequestration, N rates, semi-arid

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Authors: Wojciech J. Nowak, Natalia Maciaszek, Marcin Drajewicz

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A constant requirement to reduce greenhouse gas emissions in combination with the desire to increase gas turbine efficiency results in a continuous trend to increase the operating temperature of gas turbines. An increase in operating temperature will result in lower fuel consumption, and a higher combustion temperature will result in lower pollution release. Moreover, there is a strong trend for hydrogen to be used as an alternative and clean fuel. However, using hydrogen or hydrogen-rich fuel results in a higher combustion temperature, as well as an increase in the water vapor content in the exhaust gases. Commonly used Ni-base alloys have their limits. Moreover, the presence of water vapor worsens the oxidation behavior of Ni-based alloys at a high temperature. Therefore, a new brand of materials is demanded to be used in gas turbines operated with hydrogen-rich fuel. High-entropy alloys (HEAs) seem to be very promising materials to replace commonly used Ni-based alloys. HEAs are the group of materials consisting of at least five main equiatomic elements. These alloys can be doped by other elements in amounts less than 5 at. % in total. Thus, in the present study, NiCoCrAlFe-X alloys are studied in terms of oxidation behavior during exposure to dry and wet atmospheres up to 1000 h. NiCoCrAlFe-X alloys are doped with minor alloying elements in amounts ranging from 1-5 at.%. The effect of the chemical composition on oxidation resistance in dry and wet atmospheres will be shown and discussed.

Keywords: high entropy alloys, oxidation resistance, hydrogen fuel, water vapor

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Authors: Weiyao Zhu, Qian Qi, Ming Yue, Dongxu Ma

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Due to the nano-micro pore structures and the massive multi-stage multi-cluster hydraulic fracturing in shale gas reservoirs, the multi-scale seepage flows are much more complicated than in most other conventional reservoirs, and are crucial for the economic development of shale gas. In this study, a new multi-scale non-linear flow model was established and simplified, based on different diffusion and slip correction coefficients. Due to the fact that different flow laws existed between the fracture network and matrix zone, a three-zone composite model was proposed. Then, according to the conformal transformation combined with the law of equivalent percolation resistance, the productivity equation of a horizontal fractured well, with consideration given to diffusion, slip, desorption, and absorption, was built. Also, an analytic solution was derived, and the interference of the multi-cluster fractures was analyzed. The results indicated that the diffusion of the shale gas was mainly in the transition and Fick diffusion regions. The matrix permeability was found to be influenced by slippage and diffusion, which was determined by the pore pressure and diameter according to the Knudsen number. It was determined that, with the increased half-lengths of the fracture clusters, flow conductivity of the fractures, and permeability of the fracture network, the productivity of the fractured well also increased. Meanwhile, with the increased number of fractures, the distance between the fractures decreased, and the productivity slowly increased due to the mutual interference of the fractures. In regard to the fractured horizontal wells, the free gas was found to majorly contribute to the productivity, while the contribution of the desorption increased with the increased pressure differences.

Keywords: multi-scale, fracture network, composite model, productivity

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Authors: Y. J. Song, Q. S. Xu, X. C. Wang, H. Wang, C. Q. Li

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The catalyst of copper oxide loaded on HZSM-5 was developed for nitrous oxide (N₂O) direct decomposition. The kinetic of nitrous oxide decomposition was studied for CuO/HZSM-5 catalyst prepared by incipient wetness impregnation method. The external and internal diffusion of catalytic reaction were considered in the investigation. Experiment results indicated that the external diffusion was basically eliminated when the reaction gas mixture gas hourly space velocity (GHSV) was higher than 9000h⁻¹ and the influence of the internal diffusion was negligible when the particle size of the catalyst CuO/HZSM-5 was small than 40-60 mesh. The experiment results showed that the kinetic of catalytic decomposition of N₂O was a first-order reaction and the activation energy and the pre-factor of the kinetic equation were 115.15kJ/mol and of 1.6×109, respectively.

Keywords: catalytic decomposition, CuO/HZSM-5, kinetic, nitrous oxide

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Authors: Matheus Fernando Pereira, Varese Salvador Timoteo

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In this work, we have solved the two-dimensional advection-diffusion equation numerically for a spatially dependent solute dispersion along non-uniform flow with a pulse type source in order to make a systematic study on the influence of medium heterogeneity, initial flow velocity, and initial dispersion coefficient parameters on the solutions of the equation. The behavior of the solutions is then investigated as we change the three parameters independently. Our results show that even though the parameters represent different physical features of the system, the effect on their variation is very similar. We also observe that the effects caused by the parameters on the concentration depend on the distance from the source. Finally, our numerical results are in good agreement with the exact solutions for all values of the parameters we used in our analysis.

Keywords: advection-diffusion equation, dispersion, numerical methods, pulse-type source

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Authors: Eman H. El-Gamal, Maher E. Saleh, Mohamed Rashad, Ibrahim Elsokkary, Mona M. Abd El-Latif

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Biochar application to calcareous soils could potentially influence the nitrogen dynamics that affect the bioavailability of plants. This study was carried out to investigate the effect of incubation periods on the changes of nitrogen levels (total nitrogen TN and exchangeable ammonium NH₄⁺ and nitrate NO₃⁻) in biochar-treated calcareous soil. The incubation course was extended to 144 days at 30 ± 3 ℃ and at 50% of soil water holding capacity (WHC). Two types of biochars were obtained by pyrolysis at 500 ℃ from rice husk (RHB) and sugarcane bagasse (SCBB). The experiment was planned in a factorial experimental design with three factors (6 periods '24 days for each period' × 3 biochar types 'un-amended, RHB and SCBB' × 3 nitrogen fertilizers 'control, ammonium nitrate; AN and animal manure; AM') in a completely randomized design. The results obtained showed that the highest level of TN was found in the first 24 days of the incubation period in all treatments. However, the amount of TN was decreased with proceeding incubation period up to 144 days and reached to the lowest level at the end of incubation with values of change rate was 17.5, 16.6, and 14.6 g kg⁻¹ day⁻¹ for the un-amended, RHB and SCBB treated soil, respectively. The values of change rate in biochar-soils treated with nitrogen fertilizers were decreased gradually through the whole incubation time from 127.22 to 12.45 g kg⁻¹ day⁻¹ and from 65.00 to 13.43 g kg⁻¹ day⁻¹ for AN and AM respectively, in the case of RHB-soil. While in SCBB-soil, these values were decreased from 70.83 to 12.13 g kg⁻¹ day⁻¹ and from 59.17 to 11.48 g kg⁻¹ day⁻¹ for AN and AM treatments, respectively. The lowest concentration of exchangeable NH₄⁺ was generally found through the period from 24-48 days of incubation. However, the addition of nitrogen fertilizers, enhanced NH₄⁺ production through incubation periods. In the case of RHB-soil, the value of change rate in NH₄⁺ level in the first 24 days of incubation was 0.43 mg kg⁻¹ day⁻¹ and with the addition of AN and AM this value increased to 1.54 and 4.38 mg kg⁻¹ day⁻¹, respectively. In the case of SCBB-soil, the value of change rate in NH₄⁺ level was 0.29 mg kg⁻¹ day⁻¹ which increased to 1.04 mg kg⁻¹ day⁻¹ at the end of incubation, and due to the addition of AN and AM this value increased to 2.78 and 1.90 mg kg⁻¹ day⁻¹ in the first 24 days of incubation period, respectively. However, as compared to the control treatment, the lowest rate of change in NH₄⁺ level was found at the end of incubation. On the other hand, incubation of all biochars-amended soil and treated with AN and AM decreased the concentration levels of NO₃⁻, especially through the first 24-72 days of incubation period. As a result, the values of change rate in NO₃⁻ concentrations in all treatments were almost negative.

Keywords: ammonium nitrate, animal manure, biochar, rice husk, sugarcane bagasse

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Authors: Dina Muharib

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Specific metabolic challenges are present following spinal cord injury. The acute stage is characterized by a reduction in metabolic activity, as well as a negative nitrogen balance that cannot be corrected, even with aggressive nutritional support. Metabolic demands need to be accurately monitored to avoid overfeeding. Enteral feeding is the optimal route following SCI. When oral feeding is not possible, nasogastric, followed by nasojejunal, then by percutaneous endoscopic gastrostomy, if necessary, is suggested.

Keywords: SCI, energy, protein, nutrition assessment, eneral feeding, nitrogen balance

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Authors: Danika Tynes

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Telehealth is a promising advancement in health care, though there are certain conditions under which telehealth has a greater chance of success. This research sought to further the understanding of what conditions compel the success of telehealth adoption at the systems level applying Diffusion of Innovations (DoI) theory (Rogers, 1962). System-level indicators were selected to represent four components of DoI theory (relative advantage, compatibility, complexity, and observability) and regressed on 5 types of telehealth (teleradiology, teledermatology, telepathology, telepsychology, and remote monitoring) using multiple logistic regression. The analyses supported relative advantage and compatibility as the strongest influencers of telehealth adoption, remote monitoring in particular. These findings help to quantitatively clarify the factors influencing the adoption of innovation and advance the ability to make recommendations on the viability of state telehealth adoption. In addition, results indicate when DoI theory is most applicable to the understanding of telehealth diffusion. Ultimately, this research may contribute to more focused allocation of scarce health care resources through consideration of existing state conditions available foster innovation.

Keywords: adoption, diffusion of innovation theory, remote monitoring, system-level indicators

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Authors: Vera Marcantonio, Marcello De Falco, Mauro Capocelli, Álvaro Amado-Fierro, Teresa A. Centeno, Enrico Bocci

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Concerns about energy security, energy prices, and climate change led scientific research towards sustainable solutions to fossil fuel as renewable energy sources coupled with hydrogen as an energy vector and carbon capture and conversion technologies. Among the technologies investigated in the last decades, biomass gasification acquired great interest owing to the possibility of obtaining low-cost and CO₂ negative emission hydrogen production from a large variety of everywhere available organic wastes. Upstream and downstream treatment were then studied in order to maximize hydrogen yield, reduce the content of organic and inorganic contaminants under the admissible levels for the technologies which are coupled with, capture, and convert carbon dioxide. However, studies which analyse a whole process made of all those technologies are still missing. In order to fill this lack, the present paper investigated the coexistence of hydrothermal carbonization (HTC), sorption enhance gasification (SEG), hot gas cleaning (HGC), and CO₂ conversion by dielectric barrier discharge (DBD) plasma reactor for H₂ production from biomass waste by means of Aspen Plus software. The proposed model aimed to identify and optimise the performance of the plant by varying operating parameters (such as temperature, CaO/biomass ratio, separation efficiency, etc.). The carbon footprint of the global plant is 2.3 kg CO₂/kg H₂, lower than the latest limit value imposed by the European Commission to consider hydrogen as “clean”, that was set to 3 kg CO₂/kg H₂. The hydrogen yield referred to the whole plant is 250 gH₂/kgBIOMASS.

Keywords: biomass gasification, hydrogen, aspen plus, sorption enhance gasification

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Authors: Tinomuvonga Manenji Zhou, Eubert Mahofa, Tatenda Crispen Madzokere

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The nanostructured formulation can increase fertilizer efficacy and uptake ratio of the soil nutrients in agriculture production and save fertilizer resources. Controlled release modes have properties of both release rate and release pattern of nutrients, for fertilizers that are soluble in water might be correctly controlled. Nanoparticles can reduce the rate at which fertilizer nutrients are in the soil by leaching. A slow release NPK-hydroxyapatite nano hybrid fertilizer was synthesized using exfoliated bentonite as filler material. A simple, scalable method was used to synthesize the nitrogen-phosphorus hydroxyapatite nano fertilizer, where calcium hydroxide, phosphoric acid, and urea were used as precursor material, followed by the incorporation of potassium through a liquid grinding method. The product obtained was an NPK-hydroxyapatite nano hybrid fertilizer. A quantitative analysis was done to determine the percentage of nitrogen, phosphorus, and potassium in the hybrid fertilizer. AAS was used to determine the percentage of potassium in the fertilizer. An accelerated water test was conducted to compare the nutrient release behavior of nutrients between the synthesized NPK-hydroxyapatite nano hybrid fertilizer and commercial NPK fertilizer. The rate of release of Nitrogen, phosphorus, and potassium was significantly lower in the synthesized NPK hydroxyapatite nano hybrid fertilizer than in the convectional NPK fertilizer. The synthesized fertilizer was characterized using XRD. NPK hydroxyapatite nano hybrid fertilizer encapsulated in exfoliated bentonite thus prepared can be used as an environmentally friendly fertilizer formulation which could be extended to solve one of the major problems faced in the global fertilization of low nitrogen, phosphorus, and potassium use efficiency in agriculture.

Keywords: NPK hydroxyapatite nano hybrid fertilizer, bentonite, encapsulation, low release

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Authors: Vikas Baliram Kalyankar

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Study of ecology is important as it plays role in development of environment engineering. With the advent of technologies the study of ecosystem structure and changes in it are remaining unnoticed. The ecological succession is the sequential replacement of plant species following changes in the environment. The present study depicts the primary ecological succession in an area leveled up to the height of five feet with no signs of plant life on it. The five quadrates of 1 meter square size were observed during the study period of six months. Rain water being the only source of water in the area increased its ecological importance. The primary successor was non- leguminous plant Balonites roxburgii during the peak drought periods in the region of the summer 2013-14. The increased nitrogen content of soil after the plant implied its role in atmospheric nitrogen fixation.

Keywords: succession, Balonites roxburgii, non-leguminous plant, ecology

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Authors: Palash Kumar Mollick, Leire Olazar, Laura Santamaria, Pablo Comendador, Gartzen Lopez, Martin Olazar

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Average calorific value of a mixure of waste plastic is approximately 38 MJ/kg. Present work aims to extract maximum possible energy from a mixure of waste plastic using a DC thermal plasma in a spouted bed reactor. Plasma pyrolysis and steam reforming process has shown a potential to generate hydrogen from plastic with much below of legal limit of producing dioxins and furans as the carcinogenic gases. A spouted bed pyrolysis rector can continuously process plastic beads to produce organic volatiles, which later react with steam in presence of catalyst to results in syngas. lasma being the fourth state of matter, can carry high impact electrons to favour the activation energy of any chemical reactions. Computational Fluid Dynamic (CFD) simulation using COMSOL Multiphysics software has been performed to evaluate performance of a plasma spouted bed reactor in producing contamination free hydrogen as a green energy from waste plastic beads. The simulation results will showcase a design of a plasma spouted bed reactor for converting plastic waste into green hydrogen in a single step process. The high temperature hydrodynamics of spouted bed with plastic beads and the corresponding temperature distribution inside the reaction chamber will be critically examined for it’s near future installation of demonstration plant.

Keywords: green hydrogen, plastic waste, synthetic gas, pyrolysis, steam reforming, spouted bed, reactor design, plasma, dc palsma, cfd simulation

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Authors: Oqba Basal, András Szabó

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Legume crops are able to fix atmospheric nitrogen by the symbiotic relation with specific bacteria, which allows the use of the mineral nitrogen-fertilizer to be reduced, or even excluded, resulting in more profit for the farmers and less pollution for the environment. Soybean (Glycine max (L.) Merrill) is one of the most important legumes with its high content of both protein and oil. However, it is recommended to combine the two nitrogen sources under stress conditions in order to overcome its negative effects. Drought stress is one of the most important abiotic stresses that increasingly limits soybean yields. A precise rate of mineral nitrogen under drought conditions is not confirmed, as it depends on many factors; soybean yield-potential and soil-nitrogen content to name a few. An experiment was conducted during 2017 growing season in Debrecen, Hungary to investigate the effects of nitrogen source on the physiology and the yield of the soybean cultivar 'Boglár'. Three N-fertilizer rates including no N-fertilizer (0 N), 35 kg ha^-1 of N-fertilizer (35 N) and 105 kg ha^-1 of N-fertilizer (105 N) were applied under three different irrigation regimes; severe drought stress (SD), moderate drought stress (MD) and control with no drought stress (ND). Half of the seeds in each treatment were pre-inoculated with Bradyrhizobium japonicum inoculant. The overall results showed significant differences associated with fertilization and irrigation, but not with inoculation. Increasing N rate was mostly accompanied with increased chlorophyll content and leaf area index, whereas it positively affected the plant height only when the drought was waived off. Plant height was the lowest under severe drought, regardless of inoculation and N-fertilizer application and rate. Inoculation increased the yield when there was no drought, and a low rate of N-fertilizer increased the yield furthermore; however, the high rate of N-fertilizer decreased the yield to a level even less than the inoculated control. On the other hand, the yield of non-inoculated plants increased as the N-fertilizer rate increased. Under drought conditions, adding N-fertilizer increased the yield of the non-inoculated plants compared to their inoculated counterparts; moreover, the high rate of N-fertilizer resulted in the best yield. Regardless of inoculation, the mean yield of the three fertilization rates was better when the water amount increased. It was concluded that applying N-fertilizer to provide the nitrogen needed by soybean plants, with the absence of N₂-fixation process, is very important. Moreover, adding relatively high rate of N-fertilizer is very important under severe drought stress to alleviate the drought negative effects. Further research to recommend the best N-fertilizer rate to inoculated soybean under drought stress conditions should be executed.

Keywords: drought stress, inoculation, N-fertilizer, soybean physiology, yield

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Authors: Juliana A. Knocikova, Yann Bouret, Médéric Argentina, Laurent Counillon

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Cell volume, together with membrane potential and intracellular hydrogen ion concentration, is an essential biophysical parameter for normal cellular activity. Cell volumes can be altered by osmotically active compounds and extracellular tonicity. In this study, a simple mathematical model of osmotically induced cell swelling and shrinking is presented. Emphasis is given to water diffusion across the membrane. The mathematical description of the cellular behavior consists in a system of coupled ordinary differential equations. We compare experimental data of cell volume alterations driven by differences in osmotic pressure with mathematical simulations under hypotonic and hypertonic conditions. Implications for a future model are also discussed.

Keywords: eukaryotic cell, mathematical modeling, osmosis, volume alterations

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Authors: Mohammed Kamil, M. M. Rahman, Rosli A. Bakar

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Modeling of hydrogen fueled engine (H₂ICE) injection system is a very important tool that can be used for explaining or predicting the effect of advanced injection strategies on combustion and emissions. In this paper, a common rail injection system (CRIS) is proposed for 4-strokes 4-cylinders hydrogen fueled engine with port injection feeding system (PIH₂ICE). For this system, a numerical one-dimensional gas dynamic model is developed considering single injection event for each injector per a cycle. One-dimensional flow equations in conservation form are used to simulate wave propagation phenomenon throughout the CR (accumulator). Using this model, the effect of common rail on the injection system characteristics is clarified. These characteristics include: rail pressure, sound velocity, rail mass flow rate, injected mass flow rate and pressure drop across injectors. The interaction effects of operational conditions (engine speed and rail pressure) and geometrical features (injector hole diameter) are illustrated; and the required compromised solutions are highlighted. The CRIS is shown to be a promising enhancement for PIH₂ICE.

Keywords: common rail, hydrogen engine, port injection, wave propagation

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Authors: Priya Ruban, Thirunavoukkarasu Manikkannan, Sakthivel Ramasamy

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Sulfide is one of the major pollutants of tannery effluent which is mainly generated during the process of unhairing. Recovery of Hydrogen green fuel from sulfide wastewater using photocatalysis is a ‘Cleaner Production Method’, since renewable solar energy is utilized. It has triple advantages of the generation of H2, waste minimization and odor or pollution control. Designing of safe and green photocatalysts and developing suitable solar photoreactor is important for promoting this technology to large-scale application. In this study, green photocatalyst i.e., spinach derived carbon dots (SCDs 5 wt % and 10 wt %)/TiO2 nanocomposite was synthesized for generation of H2 from sulfide wastewater using lab-scale solar photocatalytic reactor. The physical characterization of the synthesized solar light responsive nanocomposites were studied by using DRS UV-Vis, XRD, FTIR and FESEM analysis. The absorption edge of TiO2 nanoparticles is extended to visible region by the incorporation of SCDs, which was used for converting noxious pollutant sulfide into eco-friendly solar fuel H2. The SCDs (10 wt%)-TiO2 nanocomposite exhibits enhanced photocatalytic hydrogen production i.e. ~27 mL of H2 (180 min) from simulated sulfide wastewater under LED visible light irradiation which is higher as compared to SCDs. The enhancement in the photocatalytic generation of H2 is attributed to combining of SCDs which increased the charge mobility. This work may provide new insights to usage of naturally available and cheap materials to design novel nanocomposite as a visible light active photocatalyst for the generation of H2 from sulfide containing wastewater.

Keywords: carbon dots, hydrogen fuel, hydrogen sulfide, photocatalysis, sulfide wastewater

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Authors: Andreas Gohs, Reinhold Kosfeld

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This study should be of interest for practitioners who want to predict precisely the sales numbers of vehicles equipped with an innovative propulsion technology as well as for researchers interested in applied (regional) time series analysis. The study is based on the numbers of new registrations of pure electric and hybrid cars. Methods of time series analysis like ARIMA are compared with the Bass Diffusion-model concerning their forecasting performances for new registrations in Germany at the national and federal state levels. Especially it is investigated if the additional information content from regional data increases the forecasting accuracy for the national level by adding predictions for the federal states. Results of parameters of the Bass Diffusion Model estimated for Germany and its sixteen federal states are reported. While the focus of this research is on the German market, estimation results are also provided for selected European and other countries. Concerning Bass-parameters and forecasting performances, we get very different results for Germany's federal states and the member states of the European Union. This corresponds to differences across the EU-member states in the adoption process of this innovative technology. Concerning the German market, the adoption is rather proceeded in southern Germany and stays behind in Eastern Germany except for Berlin.

Keywords: bass diffusion model, electric vehicles, forecasting performance, market diffusion

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Authors: Soyoon Bak, Sunyoung Bu, Philsu Kim

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In this paper, a backward semi-Lagrangian scheme combined with the second-order backward difference formula is designed to calculate the numerical solutions of nonlinear advection-diffusion equations. The primary aims of this paper are to remove any iteration process and to get an efficient algorithm with the convergence order of accuracy 2 in time. In order to achieve these objects, we use the second-order central finite difference and the B-spline approximations of degree 2 and 3 in order to approximate the diffusion term and the spatial discretization, respectively. For the temporal discretization, the second order backward difference formula is applied. To calculate the numerical solution of the starting point of the characteristic curves, we use the error correction methodology developed by the authors recently. The proposed algorithm turns out to be completely iteration-free, which resolves the main weakness of the conventional backward semi-Lagrangian method. Also, the adaptability of the proposed method is indicated by numerical simulations for Burgers’ equations. Throughout these numerical simulations, it is shown that the numerical results are in good agreement with the analytic solution and the present scheme offer better accuracy in comparison with other existing numerical schemes. Semi-Lagrangian method, iteration-free method, nonlinear advection-diffusion equation, second-order backward difference formula

Keywords: Semi-Lagrangian method, iteration free method, nonlinear advection-diffusion equation, second-order backward difference formula

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Authors: Geno Paul S. Cumla, Jan Mariel M. Gentiles, M. Brenda Gajelan-Samson

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Eutrophication is a process where in there is a surplus of nutrients present in a lake or river. Harmful cyanobacteria, hypoxia, and primarily algae, which contain toxins, grow because of the excess nutrients. Algal blooms can cause fish kills, limiting the light penetration which reduces growth of aquatic organisms, causing die-offs of plants and produce conditions that are dangerous to aquatic and human life. The main cause for eutrophication is the presence of excessive amounts of phosphorus (P) and nitrogen (N). Nitrogen is necessary for the production of the plant tissues and is usually used to synthesize proteins. Nitrate is a compound that contains nitrogen, and at elevated levels it can cause harmful effects. Excessive amounts of phosphorus, displaced through human activity, is the major cause of algae growth and as well as degraded water quality. To accomplish this study the Assessment of Soluble inorganic nitrogen (SIN), Assessment of Soluble reactive phosphate (SRP), Determination of Chlorophyll a (Chl-a) concentration, and Determination of Dominating Taxa were done. The study addresses the high probability of algal blooms in Maqueda Bay by assessing the biotic and abiotic factors of Antiao and Jiabong rivers. The data predicts the overgrowth of algae and to create awareness to prevent the event from taking place. The study assesses the adverse effects that could be prevented by understanding and controlling algae. This should predict future cases of algal blooms and allow government agencies which require data to create programs to prevent and assess these issues.

Keywords: eutrophication, chlorophyll a, nitrogen, phosphorus, red tide, Kjeldahl method, spectrophotometer, assessment of soluble inorganic nitrogen, SIN, assessment of soluble reactive phosphate, SRP

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Authors: Jiraphorn Satechan, Thanaphon Khamthieng, Warunee Phanwong

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This action research aimed at designing and developing the cleaning equipment to preventing dust diffusion of bus air filter. Quantitative and qualitative data collection methods were used to conduct data from October 1st, 2018 to September 30th, 2019. All of participants were male (100.0%) with aged 40- 49 years and 57.15%, of them finish bachelor degree. 71.43% of them was a driver and 57.15% of them had the working experience between 10 and 15 years. Research revealed that the participants assessed the quality of the bus air filter cleaning equipment for preventing dust diffusion at a moderate level (σ= 0.29), and 71.43 of them also suggested the development methods in order to improve the quality of bus air filters cleaning equipment as follows: 1) to install the circuit breaker for cutting the electricity and controlling the on-off of the equipment and to change the motor to the DC system, 2) should install the display monitor for wind pressure and electricity system as well as to install the air pressure gauge, 3) should install the tank lid lock for preventing air leakage and dust diffusion by increasing the blowing force and sucking power, 4) to stabilize the holding points for preventing the filter shaking while rotating and blowing for cleaning and to reduce the rotation speed in order to allow the filters to move slowly for the air system to blow for cleaning more thoroughly, 5) the amount of dust should be measured before and after cleaning and should be designed the cleaning equipment to be able to clean with a variety of filters, and sizes. Moreover, the light-weight materials should be used to build the cleaning equipment and the wheels should be installed at the base of the equipment in order to make it easier to move.

Keywords: Cleaning Equipment, Bus Air Filters, Preventing Dust Diffusion, Innovation

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Authors: Ana M. Antolín, Sandra Contreras, Francesc Medina, Didier Tichit

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Introduction: High levels of nitrates (> 50 ppm NO3-) in drinking water are potentially risky to human health. In the recent years, the trend of nitrate concentration in groundwater is rising in the EU and other countries. Conventional catalytic nitrate reduction processes into N2 and H2O lead to some toxic intermediates and by-products, such as NO2-, NH4+, and NOx gases. Alternatively, photocatalytic nitrate removal using solar irradiation and heterogeneous catalysts is a very promising and ecofriendly technique. It has been scarcely performed and more research on highly efficient catalysts is still needed. In this work, different nanocatalysts supported on Aeroxide Titania P25 (P25) have been prepared varying: 0.5-4 % wt. Ag); Pt (2, 4 % wt.); Pt precursor (H2PtCl6/K2PtCl6); and impregnation order of both metals. Pt was chosen in order to increase the selectivity to N2 and decrease that to NO2-. Catalysts were characterized by nitrogen physisorption, X-Ray diffraction, UV-visible spectroscopy, TEM and X Ray-Photoelectron Spectroscopy. The aim was to determine the influence of the composition and the preparation method of the catalysts on the conversion and selectivity in the nitrate reduction, as well as going through an overall and better understanding of the process. Nanocatalysts synthesis: For the mono and bimetallic catalysts preparation, wise-drop wetness impregnation of the precursors (AgNO3, H2PtCl6, K2PtCl6) followed by a reduction step (NaBH4) was used to obtain the metal colloids. Results and conclusions: Denitration experiments were performed in a 350 mL PTFE batch reactor under inert standard operational conditions, ultraviolet irradiations (λ=254 nm (UV-C); λ=365 nm (UV-A)), and presence/absence of hydrogen gas as a reducing agent, contrary to most studies using oxalic or formic acid. Samples were analyzed by Ionic Chromatography. Blank experiments using respectively P25 (dark conditions), hydrogen only and UV irradiations without hydrogen demonstrated a clear influence of the presence of hydrogen on nitrate reduction. Also, they demonstrated that UV irradiation increased the selectivity to N2. Interestingly, the best activity was obtained under ultraviolet lamps, especially at a closer wavelength to visible light irradiation (λ = 365 nm) and H2. 2% Ag/P25 leaded to the highest NO3- conversion among the monometallic catalysts. However, nitrite quantities have to be diminished. On the other hand, practically no nitrate conversion was observed with the monometallics based on Pt/P25. Therefore, the amount of 2% Ag was chosen for the bimetallic catalysts. Regarding the bimetallic catalysts, it is observed that the metal impregnation order, amount and Pt precursor highly affects the results. Higher selectivity to the desirable N2 gas is obtained when Pt was firstly added, especially with K2PtCl6 as Pt precursor. This suggests that when Pt is secondly added, it covers the Ag particles, which are the most active in this reaction. It could be concluded that Ag allows the nitrate reduction step to nitrite, and Pt the nitrite reduction step toward the desirable N2 gas.

Keywords: heterogeneous catalysis, hydrogenation, nanocatalyst, nitrate removal, photocatalysis

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Authors: N. Soli, B. Chaouachi, M. Bourouis

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We propose in this work the thermodynamic feasibility study of the operation of a refrigerating machine with absorption-diffusion with mixtures of hydrocarbons. It is for a refrigerating machine of low power (300 W) functioning on a level of temperature of the generator lower than 150 °C (fossil energy or solar energy) and operative with non-harmful fluids for the environment. According to this study, we determined to start from the digraphs of Oldham of the different binary of hydrocarbons, the minimal and maximum temperature of operation of the generator, as well as possible enrichment. The cooling medium in the condenser and absorber is done by the ambient air with a temperature at 35 °C. Helium is used as inert gas. The total pressure in the cycle is about 17.5 bars. We used suitable software to modulate for the two binary following the system propylene /butane and propylene/pentane. Our model is validated by comparison with the literature’s resultants.

Keywords: absorption, DAR cycle, diffusion, propyléne

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Authors: Jyun-Hao Liao, Chien-Ju Chen, Chia-Jui Yu, Meng Chyi Wu, Chia-Ching Wu

Abstract:

In this letter, we reported the fabrication of InGaAs micro-photodiode sensor array with the rapid thermal diffusion (RTD) technique. The spin-on dopant source Zn was used to form the p-type region in InP layer. Through the RTD technique, the InP/InGaAs heterostructure was formed. We improved our fabrication on the p-i-n photodiode to micro size which pixel is 7.8um, and the pitch is 12.8um. The proper SiNx was deposited to form the passivation layer. The leakage current of single pixel decrease to 3.3pA at -5V, and 35fA at -10mV. The leakage current densities of each voltage are 21uA/cm² at -5V and 0.223uA/cm² at -10mV. As we focus on the wavelength from 0.9um to 1.7um, the optimized Si/Al₂O₃ bilayers are deposited to form the AR-coating.

Keywords: InGaAs, micro sensor array, p-i-n photodiode, rapid thermal diffusion, Zn diffusion

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Authors: Kaouka Alaeddine, K. Benarous

Abstract:

This study aims to obtain a surface of pure titanium and titanium alloy Ti-64Al with high performance by the diffusion process. Two agents metal alloy have been used in this treatment, niobium (Nb) and molybdenum (Mo), spread on elemental titanium and Ti-64Al alloy. Nb and Mo are used as powder form to increase the contact surface and to improve the distribution. Both Mo and Nb are distributed on samples of Ti and Ti-64Al at 1100 °C and 1200 °C for 3 h. They were performed to effect different experiments objectives. This work was achieved to improve some properties and microstructure of Ti and Ti-64Al surface, using optical microscopy and SEM and study some mechanical properties. The effects of temperature and the powder contents on the microstructure of Ti and Ti-64Al alloy, different phases and hardness value of Ti and Ti-64Al alloy were determined. Experimental results indicate that increasing the powder contents and/or the temperature, the α + β phases change to the equiaxed β lamellar structure. In particular, experiments in 1200 °C were created by diffusion α + β phases both equiaxed β phase laminar and α + β phase, thus meeting the objectives were established in the work. In addition, simulation results are used for comparison with the experimental results by DICTRA software.

Keywords: diffusion, powder metallurgy, titanium alloy, molybdenum, niobium

Procedia PDF Downloads 131

Authors: Sayantan Khanra, Rojers P. Joseph

Abstract:

This study attempts to analyze the impact of demography and service quality on the adoption and diffusion of e-Government services in the context of India. The objective of this paper is to study the users' perception about e-Government services and investigate the key variables that are most salient to the Indian populace. At the completion of this study, a research model that would help to understand the relationship involving the demographic variables and service quality dimensions, and the willingness to adopt e-Government services is expected to be developed. Dedicated authorities, particularly those in developing economies, may use that model or its augmented versions to design and update e-Government services and promote their use among citizens. After all, enhanced public participation is required to improve efficiency, engagement and transparency in the implementation of the aforementioned services.

Keywords: adoption and diffusion of e-government services, demographic variables, hierarchical regression analysis, service quality dimensions

Procedia PDF Downloads 267

Authors: Oustani Mabrouka, Halilat Md Tahar, Hannachi Slimane

Abstract:

This study was conducted on representative and contrasting soils of arid regions. It focuses on the compared influence of two organic fertilizers: poultry manure (PM) and bovine manure (BM) on improving the microbial functioning of non-saline (SS) and saline (SSS) soils, in particularly, the process of mineralization of nitrogen and carbon. The microbiological activity was estimated by respirometric test (CO2–C emissions) and the extraction of two forms of mineral nitrogen (NH4+-N and NO3--N). Thus, after 56 days of incubation under controlled conditions (28 degrees and 80 per cent of the field capacity), the two types of manures showed that the mineralization activity varies according to type of soil and the organic substrate itself. However, the highest cumulative quantities of CO2–C, NH4+–N and NO3-–N obtained at the end of incubation were recorded in non-saline (SS) soil treated with poultry manure with 1173.4, 4.26 and 8.40 mg/100 g of dry soil, respectively. The reductions in rates of release of CO2–C and of nitrification under saline conditions were 21 and 36, 78 %, respectively. The influence of organic substratum on the microbial density shows a stimulating effect on all microbial groups studied. The whole results show the usefulness of two types of manures for the improvement of the microbiological functioning of arid soils.

Keywords: Salinity, Organic matter, Microorganisms, Mineralization, Nitrogen, Carbon, Arid regions

Procedia PDF Downloads 256

Authors: H. Bhuyan, S. Mändl, M. Favre, M. Cisternas, A. Henriquez, E. Wyndham, M. Walczak, D. Manova

Abstract:

The 470 Li-24 Cr and 460Li-21 Cr are two alloys belonging to the next generation of super-ferritic nickel free stainless steel grades, containing titanium (Ti), niobium (Nb) and small percentage of carbon (C) and nitrogen (N). The addition of Ti and Nb improves in general the corrosion resistance while the low interstitial content of C and N assures finer precipitates and greater ductility compared to conventional ferritic grades. These grades are considered an economic alternative to AISI 316L and 304 due to comparable or superior corrosion. However, since 316L and 304 can be nitrided to improve the mechanical surface properties like hardness and wear; it is hypothesize that the tribological properties of these super-ferritic stainless steels grades can also be improved by plasma nitriding. Thus two sets of plasma immersion ion implantation experiments have been carried out, one with a high pressure capacitively coupled radio frequency plasma at PUC Chile and the other using a low pressure microwave plasma at IOM Leipzig, in order to explore further improvements in the mechanical properties of 470 Li-24 Cr and 460Li-21 Cr steel. Nitrided and unnitrided substrates have been subsequently investigated using different surface characterization techniques including secondary ion mass spectroscopy, scanning electron microscopy, energy dispersive x-ray analysis, Vickers hardness, wear resistance, as well as corrosion test. In most of the characterizations no major differences have been observed for nitrided 470 Li-24 Cr and 460Li-21 Cr. Due to the ion bombardment, an increase in the surface roughness is observed for higher treatment temperature, independent of the steel types. The formation of chromium nitride compound takes place only at a treatment temperature around 4000C-4500C, or above. However, corrosion properties deteriorate after treatment at higher temperatures. The physical characterization results show up to 25 at.% of nitrogen for a diffusion zone of 4-6 m, and a 4-5 times increase in hardness for different experimental conditions. The samples implanted with temperature higher than 400 °C presented a wear resistance around two orders of magnitude higher than the untreated substrates. The hardness is apparently affected by the different roughness of the samples and their different profile of nitrogen.

Keywords: ion implantation, plasma, RF and microwave plasma, stainless steel

Procedia PDF Downloads 448

Authors: Katja Ignatieva, Patrick Wong

Abstract:

We investigated the dynamics of high frequency energy prices, including crude oil and electricity prices. The returns of underlying quantities are modelled using various parametric models such as stochastic framework with jumps and stochastic volatility (SVCJ) as well as non-parametric alternatives, which are purely data driven and do not require specification of the drift or the diffusion coefficient function. Using different statistical criteria, we investigate the performance of considered parametric and nonparametric models in their ability to forecast price series and volatilities. Our models incorporate possible seasonalities in the underlying dynamics and utilise advanced estimation techniques for the dynamics of energy prices.

Keywords: stochastic volatility, affine jump-diffusion models, high frequency data, model specification, markov chain monte carlo

Procedia PDF Downloads 76

Authors: F. Nejati, Sh. Dokhani

Abstract:

Bitterness is a flavor defect encountered in some cheeses, such as Iranian white brined cheese and is responsible for reducing acceptability of the cheeses. The objective of this study was to investigate the effect of an adjunct culture on removal of bitterness fro, Iranian white-brined cheese. The chemical and proteolysis characteristics of the cheese were also monitored. Bitter cheeses were made using overdose of clotting enzyme with and without L. helveticus CH-1 as an adjunct culture. Cheese made with normal doses of clotting enzyme was used as the control. Adjunct culture was applied in two different forms: attenuated and non-attenuated. Proteolysis was assessed by measuring the amount of water soluble nitrogen, 12% trichloroacetic acid soluble nitrogen and total free amino acids during ripening. A taste panel group also evaluated the cheeses at the end of ripening period. Results of the statistical analysis showed that the adjunct caused considerable proteolysis and the level of water soluble nitrogen and 12% soluble nitrogen fractions were found to be significantly higher in the treatment involving L. helveticus (respectively P < 0.05 and P < 0.01). Regarding to organoleptic evaluations, the non-shocked adjunct culture caused reduction in bitterness and enhancement of flavor in cheese.

Keywords: bitterness, Iranian white brined cheese, Lactobacillus helveticus, ripening

Procedia PDF Downloads 349

Authors: Fatemeh Nejati, Shahram Dokhani

Abstract:

Bitterness is a flavor defect encountered in some cheeses, such as Iranian white brined cheese and is responsible for reducing acceptability of the cheeses. The objective of this study was to investigate the effect of an adjunct culture on removal of bitterness fro, Iranian white-brined cheese. The chemical and proteolysis characteristics of the cheese were also monitored. Bitter cheeses were made using overdose of clotting enzyme with and without L. helveticus CH-1 as an adjunct culture. Cheese made with normal doses of clotting enzyme was used as the control. Adjunct culture was applied in two different forms: attenuated and non-attenuated. Proteolysis was assessed by measuring the amount of water soluble nitrogen, 12% trichloroacetic acid soluble nitrogen and total free amino acids during ripening. A taste panel group also evaluated the cheeses at the end of ripening period. Results of the statistical analysis showed that the adjunct caused considerable proteolysis and the level of water soluble nitrogen and 12% soluble nitrogen fractions were found to be significantly higher in the treatment involving L. helveticus (respectively P < 0.05 and P < 0.01). Regarding to organoleptic evaluations, the non-shocked adjunct culture caused reduction in bitterness and enhancement of flavor in cheese.

Keywords: Bitterness, Iranian white brined Cheese, Lactobacillus helveticus, Ripening

Procedia PDF Downloads 441