Recent Submissions
New records verified within the last 60 days
Showing records 1010 to 1034 of 1190. [First] Page: 1 38 39 40 41 42 43 44 45 46 Last
Response Surface Methodology: An Optimal Design for Maximising the Efficiency of Microwave-Assisted Extraction of Total Phenolic Compounds from Coriandrum sativum Leaves
Soraya Hihat, Noureddine Touati, Abdelhakim Sellal, Khodir Madani
June 5, 2024 (v1)
Keywords: Coriandrum sativum, microwave-assisted extraction, response surface methodology, total antioxidant capacity, total phenolic compounds
The optimization of total phenolic compounds (TPC) extraction yield and maximization of total antioxidant capacity (TAC) from coriander leaves were investigated using response surface methodology. The extraction of TPC was carried out using microwave-assisted extraction. A Box-Behnken design was used to study the effects of the three independent variables, solvent concentration (ethanol/water 20−80%), microwave power (100−500 watt) and irradiation time (30−150 s) on the response. A second-order polynomial model was used to predict the reaction. The regression analysis showed that about 99% of the variations could be explained by the models. The predicted values were 50.97 GAE/g dw and 5.75 mg GAE/g dw for TPC and TAC, respectively. The reaction surface analysis showed that the optimum extraction parameters that maximized the extraction of antioxidants yield were 52.62% ethanol, 452.12 watt and 150 s. Under optimal conditions, the experimental values for TPC and TAC were 49.63 ± 0.93 mg... [more]
Improving Polyp Segmentation with Boundary-Assisted Guidance and Cross-Scale Interaction Fusion Transformer Network
Lincen Jiang, Yan Hui, Yuan Fei, Yimu Ji, Tao Zeng
June 5, 2024 (v1)
Keywords: boundary-assisted guidance, cross-scale interaction, polyp segmentation, transformer
Efficient and precise colorectal polyp segmentation has significant implications for screening colorectal polyps. Although network variants derived from the Transformer network have high accuracy in segmenting colorectal polyps with complex shapes, they have two main shortcomings: (1) multi-level semantic information at the output of the encoder may result in information loss during the fusion process and (2) failure to adequately suppress background noise during segmentation. To address these challenges, we propose a cross-scale interaction fusion transformer for polyp segmentation (CIFFormer). Firstly, a novel feature supplement module (FSM) supplements the missing details and explores potential features to enhance the feature representations. Additionally, to mitigate the interference of background noise, we designed a cross-scale interactive fusion module (CIFM) that combines feature information between different layers to obtain more multi-scale and discriminative representative f... [more]
Improving Microalgae Feasibility Cultivation: Preliminary Results on Exhausted Medium Reuse Strategy
Luigi Marra, Elena Aurino, Francesca Raganati, Antonino Pollio, Antonio Marzocchella
June 5, 2024 (v1)
Subject: Environment
Keywords: medium reuse, microalgae, substrate recovery, water footprint
Although microalgae exploitation is very promising, process sustainability is undermined by biomass production and harvesting. Among the various bottlenecks of the production process, particular attention should be paid to the water footprint. Indeed, a huge volume of water is required in microalgae production. Water reuse can support both the water footprint and medium cost reduction, saving water and unconverted substrates. The present study reports preliminary results regarding the utilization of a water reuse strategy for two Chlorophyta microalgae under batch conditions. Growth parameters and chlorophyll content are monitored and the optimal amount of reused medium is assessed. The results show that 70% of the medium can be reused with no loss of specific growth rate and chlorophyll fraction for Pseudococcomyxa simplex in three consecutive batch cultivations. By contrast, a significant decline in Chlorella vulgaris growth was observed after the first cultivation in reused medium,... [more]
Predictive Modeling for Microchannel Flow Boiling Heat Transfer under the Dual Effect of Gravity and Surface Modification
Haoxian Wu, Shengnan Zhou, Dongwei Wang, Yunbo Yang, Linglin Liu, Huijie Mao, Bifen Shu
June 5, 2024 (v1)
Keywords: dual effect, gravity, heat transfer model, micro devices, surface modification
This paper investigates the heat transfer performance of flow boiling in microchannels under the dual effect of gravity and surface modification through both experimental studies and mechanistic analysis. Utilizing a test bench with microchannels featuring surfaces of varying wettability levels and adjustable flow directions, multiple experiments on R134-a flow boiling heat transfer under the effects of gravity and surface modification were conducted, resulting in 1220 sets of experimental data. The mass flux ranged from 735 kg/m2s to 1271 kg/m2s, and the heating heat flux density ranged from 9 × 103 W/m2 to 46 × 103 W/m2. The experimental results revealed the differences in the influence of different gravity and surface modification conditions on heat transfer performance. It was found that the heat transfer performance of super-hydrophilic surfaces in horizontal flow is optimal and more stable heat transfer performance is observed when gravity is aligned with the flow direction. And... [more]
The Inversion Method of Shale Gas Effective Fracture Network Volume Based on Flow Back Data—A Case Study of Southern Sichuan Basin Shale
Dengji Tang, Jianfa Wu, Jinzhou Zhao, Bo Zeng, Yi Song, Cheng Shen, Lan Ren, Yongzhi Huang, Zhenhua Wang
June 5, 2024 (v1)
Keywords: effective fracture network volume (EFNV), flow back data, fracture network fracturing, Genetic Algorithm, shale gas
Fracture network fracturing is pivotal for achieving the economical and efficient development of shale gas, with the connectivity among fracture networks playing a crucial role in reservoir stimulation effectiveness. However, flow back data that reflect fracture network connectivity information are often ignored, resulting in an inaccurate prediction of the effective fracture network volume (EFNV). The accurate calculation of the EFNV has become a key and difficult issue in the field of shale fracturing. For this reason, the accurate shale gas effective fracture network volume inversion method needs to be improved. Based on the flow back characteristics of fracturing fluids, a tree-shaped fractal fracture flow back mathematical model for inversion of EFNV was established and combined with fractal theory. A genetic algorithm workflow suitable for EFNV inversion of shale gas was constructed based on the flow back data after fracturing, and the fracture wells in southern Sichuan were used... [more]
Optimizing Microwave-Assisted Extraction from Levisticum officinale WDJ Koch Roots Using Pareto Optimal Solutions
Michał Plawgo, Sławomir Kocira, Andrea Bohata
June 5, 2024 (v1)
Keywords: antioxidant activity, Extraction, lovage, Modelling, Pareto optimality, polyphenols
The current research trend is not only focused on advanced techniques to intensify the extraction of bioactive compounds from plants, but also on the optimization process. The objective of this work was the implementation of the multiple criteria analysis using navigation on Pareto sets to determine the optimal parameters for the microwave-assisted extraction of Levisticum officinale WDJ Koch roots in order to obtain the maximum efficiency of the antioxidant potential of the extracts. The optimized parameters were extraction time, microwave power, and plant biomass/solvent ratio, while the evaluation criteria were based on the total phenols, flavonoids, reducing sugars, and antioxidant capacity. It was shown that the process parameters analyzed, i.e., biomass/solvent ratio, process time, and microwave power, determined the extraction efficiency of total phenolic content (TPC). A different observation was made for the analysis of total flavonoid content (TFC) and total antioxidant poten... [more]
Improving Ammonia Emission Model of Urea Fertilizer Fluidized Bed Granulation System Using Particle Swarm Optimization for Sustainable Fertilizer Manufacturing Practice
Norhidayah Mohamad, Nor Azlina Ab. Aziz, Anith Khairunnisa Ghazali, Mohd Rizal Salleh
June 5, 2024 (v1)
Subject: Optimization
Keywords: ammonia emission, granulation, Particle Swarm Optimization, urea fertilizer
Granulation is an important class of production processes in food, chemical and pharmaceutical manufacturing industries. In urea fertilizer manufacturing, fluidized beds are often used for the granulation system. However, the granulation processes release ammonia to the environment. Ammonia gas can contribute to eutrophication, which is an oversupply of nitrogen and acidification to the ecosystems. Eutrophication may cause major disruptions of aquatic ecosystems. It is estimated that global ammonia emissions from urea fertilizer processes are approximately at 10 to 12 Tg N/year, which represents 23% of overall ammonia released globally. Therefore, accurate modeling of the ammonia emission by the urea fertilizer fluidized bed granulation system is important. It allows for the system to be operated efficiently and within sustainable condition. This research attempts to optimize the model of the system using the particle swarm optimization (PSO) algorithm. The model takes pressure (Mpa),... [more]
The Storage Process of Electric Energy Produced from Renewable Sources from Hydrogen to Domestic Hot Water Heating
Dorel Stoica, Lucian Mihăescu, Gheorghe Lăzăroiu, George Cristian Lăzăroiu
June 5, 2024 (v1)
Keywords: green hydrogen, power grids, renewable electricity, storage processes
The expansion of renewable electricity storage technologies, including green hydrogen storage, is spurred by the need to address the high costs associated with hydrogen storage and the imperative to increase storage capacity. The initial section of the paper examines the intricacies of storing electricity generated from renewable sources, particularly during peak periods, through green hydrogen. Two primary challenges arise: firstly, the complexity inherent in the storage technology and its adaptation for electricity reproduction; and secondly, the cost implications throughout the technological chain, resulting in a significant increase in the price of the reproduced energy. Electric energy storage emerges as a pivotal solution to accommodate the growing proportion of renewable energy within contemporary energy systems, which were previously characterized by high stability. During the transition to renewable-based energy systems, optimizing energy storage technology to manage power flu... [more]
The Application of Rotary Twist Collecting Actuator Systems for Camellia oleifera Flower Bud Collection
Qing Zhao, Lijun Li, Zhifeng Yang
June 5, 2024 (v1)
Subject: Environment
Keywords: Camellia oleifera, flower bud collecting, rotary twist, shear type, triple-finger linkage
Pollen transmission of Camellia oleifera is affected by climate and environment, and the quality of natural pollination is not high, which seriously affects the yield of Camellia oleifera. Artificial pollination is an effective way to solve the low fruit setting rate of natural pollination, but the problem to be solved urgently in artificial pollination is the collection of a large amount of pollen. At present, there is no mechanized equipment for Camellia oleifera flower bud collection, so developing an efficient pollen collection device has become a key problem that restricts the high-quality development of Camellia oleifera. In this paper, on the basis of measuring the tensile force, the shearing force, and the torsional moment required to remove Camellia Oleifera flower bud from the branch, which are 8.968 N, 13.94 N, and 0.0178 N·m, respectively, three types of Camellia oleifera flower bud collecting actuators were designed. According to the results of parameter design, feasibilit... [more]
Combustion Characteristics, Kinetics and Thermodynamics of Peanut Shell for Its Bioenergy Valorization
Jialiu Lei, Xiaoyu Liu, Biao Xu, Zicong Liu, Yongjun Fu
June 5, 2024 (v1)
Subject: Other
Keywords: combustion characteristics, isoconversional methods, kinetics and thermodynamics, peanut shell, thermogravimetric analysis
To realize the utilization of peanut shell, this study investigates the combustion behavior, chemical kinetics and thermodynamic parameters of peanut shell using TGA under atmospheric air at the heating rates of 10, 20, and 30 K/min. Results indicate that increasing the heating rate leads to higher ignition, burnout, and peak temperatures, as observed in the TG/DTG curves shifting to the right. Analysis of combustion performance parameters suggest that higher heating rates can enhance combustion performances. Kinetic analysis using two model-free methods, KAS and FWO, shows that the activation energy (Eα) ranges from 93.30 to 109.65 kJ/mol for FWO and 89.72 to 103.88 kJ/mol for KAS. The data fit well with coefficient of determination values (R2) close to 1 and the mean squared error values (MSE) less than 0.006. Pre-exponential factors using FWO range from 2.19 × 106 to 8.08 × 107 s−1, and for KAS range from 9.72 × 105 to 2.25 × 107 s−1. Thermodynamic analysis indicates a low-energy ba... [more]
High-Performance Porous pSi/Ag@C Anode for Lithium-Ion Batteries
Kefan Li, Xiang Li, Liang Yuan, Zewen Han, Mengkui Li, Rui Ji, Yixin Zhan, Kai Tang
June 5, 2024 (v1)
Keywords: anode, kerf loss silicon, pSi/Ag@C composite, silver particles
Silicon represents one of the most attractive anode materials in lithium-ion batteries (LIBs) due to its highest theoretical specific capacity. Thus, there is a most urgent need to prepare Si-based nano materials in a very efficient way and develop some reasonable approaches for their modification in order to resolve the short-falls of Si anodes, which include both low conductivity and huge volume changes during intercalation of lithium ions. In this work, the kerf loss silicon (KL Si) from the photovoltaic industry has been used as an inexpensive Si source for the preparation of a porous silicon/silver/carbon composite (pSi/Ag@C) as an anode material. Porous silicon was embedded with Ag particles via the Ag-catalyzed chemical etching process, providing additional space to accommodate the large volume expansion of silicon. After carbon coating from polymerization of tannic acid on the surface of pSi/Ag, a high-speed conductive network over the surface of silicon was built and contribut... [more]
Comparative Study of the Stilbenes and Other Phenolic Compounds in Cabernet Sauvignon Wines Obtained from Two Different Vinifications: Traditional and Co-Inoculation
Aleksandar Petrović, Nikolina Živković, Ljilja Torović, Ana Bukarica, Vladan Nikolić, Jelena Cvejić, Ljiljana Gojković-Bukarica
June 5, 2024 (v1)
Subject: Biosystems
Keywords: co-inoculation, non-Saccharomyces yeast, phenolic compounds, quercetin, Torulaspora delbrueckii, trans-resveratrol
From grape cultivation to ripening and harvest timing to processing, each step of the winemaking process can be a critical point when it comes to wine quality and phenolic composition. In this study, the influence of winemaking technology on resveratrol and quercetin content, as well as other polyphenolic compounds, was investigated. Resveratrol is a non-flavonoid polyphenolic stilbene synthesized by grape skin when damaged by infectious diseases or ionizing radiation. Quercetin is a phenol found in grape skins and stems and is produced to protect grapes from UV light damage. Trans-resveratrol and quercetin are known to act as antioxidants, reduce the risk of atherosclerosis and type 2 diabetes, inhibit the growth of cancer cells, and prevent the release of allergic and inflammatory molecules. However, the question was whether red wine could be enriched with these phenols using a co-inoculation winemaking technology. The main new idea was to completely replace the cold maceration proce... [more]
Study on the Mechanism of Carbon Dioxide Miscible Fracturing Fluid Huff and Puff in Enhanced Oil Recovery
Shijing Xu, Changquan Wang, Bin Gao, Tiezheng Wang
June 5, 2024 (v1)
Keywords: CO2 miscible fracturing fluid, enhanced oil recovery, huff and puff, low-permeability reservoir, minimum miscible pressure
Carbon dioxide (CO2) miscible fracturing huff-and-puff technology now plays a pivotal role in enhancing crude oil recovery rates, particularly in reservoirs with challenging physical properties, strong water sensitivity, high injection pressure, and complex water-injection dynamics. In this study, the oil-increasing mechanism and huff-and-puff effect of CO2 miscible fracturing fluid are investigated through a comprehensive experimental approach. Specifically, experiments on PVT gas injection expansion, minimum miscible pressure, and CO2 miscible fracturing fluid huff and puff are conducted on the G fault block reservoir of the J Oilfield. The experimental findings demonstrate that injecting CO2 into reservoirs leads to an expansion in oil volume, a reduction in viscosity, and an increase in saturation pressure. Crude oil extraction is further enhanced by the addition of solubilizers and viscosity reducers. The use of solubilizers not only increases oil recovery rates but also reduces t... [more]
Fungal Isolation, Detection, and Quantification of Aflatoxins in Nuts Sold in the Lebanese Market
Heba Hellany, Jean Claude Assaf, Joseph Matta, Mahmoud I. Khalil
June 5, 2024 (v1)
Subject: Biosystems
Keywords: aflatoxins, ELISA, HPLC, Lebanese nuts, toxigenic fungi
This study examines the prevalence of aflatoxin contamination in 160 nut samples, both shelled and unshelled (including pistachios, peanuts, and walnuts), from the Lebanese market, focusing on their fungal contamination and specific toxigenic strains. Aflatoxin B1 (AFB1), known for its potent carcinogenic and immunosuppressive properties, was detected in various samples. Moisture content analysis showed that unshelled nuts often exceeded maximum moisture limits more frequently than shelled nuts, with levels ranging from 1.9 to 9.5%. The predominant fungal genus identified through cultivation on potato dextrose agar (PDA) plates was Aspergillus. In total, 55% of samples were contaminated with A. flavus and 45% with A. niger. All toxigenic strains isolated were identified as Aspergillus flavus. The aflatoxins, particularly AFB1, were quantified using the enzyme-linked immunosorbent assay (ELISA) and reversed-phase high-performance liquid chromatography (HPLC), revealing contamination in... [more]
Development of New Series of Certified Reference Materials for Ferrosilicon Magnesium Alloys
Justyna Kostrzewa, Jacek Anyszkiewicz, Tadeusz Gorewoda, Ewa Jamroz, Kjell Blandhol, Alf Yngve Guldhav, Magdalena Knapik, Jadwiga Charasińska, Agata Jakóbik-Kolon
June 5, 2024 (v1)
Subject: Materials
Keywords: certified reference materials, silicon alloys, traceability
This paper presents a practical approach to the production of certified reference materials (CRMs) for ferrosilicon magnesium alloys. These new CRMs are predicted to be used in fast X-ray fluorescence spectrometry (XRF) analysis, which does not require sample digestion and does not result in the production of acidic sewage and emissions, contrary to the classical and instrumental techniques currently used in laboratories. Four new certified reference materials (CRMs) were developed to fill the gap in the reference materials market and ensure fast and traceable analyses. The materials were produced with an industrial process and then homogenized and mixed to achieve the required compositions and level of homogeneity. The homogeneity was determined using specially developed analytical methods and confirmed statistically by ANOVA. Additionally, the results of the tests show the short- and long-term stabilities of the new materials. The certified values for specific element contents were d... [more]
Thermal Stress Mechanism of Thermochemical Reactor of 5 kW Solar Simulator with Temperature Distribution as the Load Condition
Xing Huang, Yan Lin, Xin Yao, Yang Liu, Fanglin Gao, Hao Zhang
June 5, 2024 (v1)
Subject: Materials
Keywords: safety, solar thermochemical reactor, temperature field, thermal stress
In this paper, a solar thermochemical reactor is designed based on a 5 kW non-coaxial concentrating solar simulator, and a mathematical model is established for thermal calculations. The calculated temperature distribution is used as a load condition for thermal stress analyses. The model is used to study the influence of the solar simulator power, solar reactor inner wall material’s emissivity, working pressure, gas inlet velocity, and thermocouple opening diameter on the thermal stress of the solar reactor. The results show that thermal stress increases with the increase in solar simulator power and the emissivity of the inner wall material in the solar reactor. The inlet velocity and working pressure have little effect on the thermal stress of the reactor and cannot prevent damage to the reactor. In the case of maintaining the diameter of the thermocouple at the front end of the reactor, increasing the diameter of the thermocouple inside the reactor leads to an increase in thermal s... [more]
Plateau-Adapted Single-Pump, Single-Bed Vacuum Pressure Swing Adsorption Oxygen Generation Process Simulation and Optimization
Yingying Zhang, Yanbin Li, Zhenxing Song, Hongyun Sun, Bolun Wen, Junming Su, Jun Ma, Yanjun Zhang
June 5, 2024 (v1)
Keywords: numerical simulation, plateau oxygen generation, vacuum pressure swing adsorption
To enhance the oxygen guarantee capacity in high altitude areas and address the challenges of traditional pressure swing adsorption oxygen generation fixed equipment with large volume and multiple device modules, a novel single-reversible-pump single-bed vacuum pressure swing adsorption (VPSA) oxygen generation process was proposed and simulated. This study investigated the effects of purge on oxygen productivity, purity, recovery, and energy consumption, determining that the optimum ratio of total oxygen in the purge gas to the total oxygen in the feed gas (P/F) was 0.176. A set of principle prototypes was developed and validated in plains. The process performance was then simulated and studied at altitudes of 3000 m, 4000 m, and 5000 m. Finally, the optimization was carried out by adjusting the product flow rate and feed flow rate, revealing that the best performance can be achieved when the oxygen purity exceeded 90% with lower energy consumption or larger productivity than the opti... [more]
Performance Improvement of an Electric Vehicle Charging Station Using Brain Emotional Learning-Based Intelligent Control
Sherif A. Zaid, Hani Albalawi, Aadel M. Alatwi, Atef Elemary
June 5, 2024 (v1)
Keywords: brain emotional learning intelligent control, charging station, electric vehicle, PV
Electric vehicle (EV) charging facilities are essential to their development and deployment. These days, autonomous microgrids that use renewable energy resources to energize charging stations for electric vehicles alleviate pressure on the public electricity grid. Nevertheless, controlling and managing such charging stations’ energy is difficult due to the nonlinearity and irregular character of renewable energy sources. The current research recommends using a Brain Emotional Learning Intelligent Control (BELBIC) controller to enhance an autonomous EV charging station’s performance and power management. The charging station uses a battery to store energy and is primarily powered by photovoltaic (PV) solar energy. The principles of BELBIC are dependent on emotional cues and sensory inputs, and they are based on an emotion processing system in the brain. Noise and parameter variations do not affect this kind of controller. In this study, the performance of a conventional proportional−in... [more]
Propagation Mechanism and Suppression Strategy of DC Faults in AC/DC Hybrid Microgrid
Chun Xiao, Yulu Ren, Qiong Cao, Ruifen Cheng, Lei Wang
June 5, 2024 (v1)
Keywords: AC/DC hybrid microgrid, bidirectional power converter, current limiting strategy, fault propagation, mechanism analysis
Due to their efficient renewable energy consumption performance, AC/DC hybrid microgrids have become an important development form for future power grids. However, the fault response will be more complex due to the interconnected structure of AC/DC hybrid microgrids, which may have a serious influence on the safe operation of the system. Based on an AC/DC hybrid microgrid with an integrated bidirectional power converter, research on the interaction impact of faults was carried out with the purpose of enhancing the safe operation capability of the microgrid. The typical fault types of the DC sub-grid were selected to analyze the transient processes of fault circuits. Then, AC current expressions under the consideration of system interconnection structure were derived and, on this basis, we obtained the response results of non-fault subnets under the fault process, in order to reveal the mechanism of DC fault propagation. Subsequently, a current limitation control strategy based on virtu... [more]
Solid−Liquid Two-Phase Flowmeter Flow-Passage Wall Erosion Evolution Characteristics and Calibration of Measurement Accuracy
Wei Han, Lumin Yan, Rennian Li, Jing Zhang, Xiang Yang, Lei Ji, Yan Qiang
June 5, 2024 (v1)
Subject: Environment
Keywords: erosion characteristics, measurement accuracy, particle dynamics parameters
Solid−liquid two-phase flowmeters are widely used in critical sectors, such as petrochemicals, energy, manufacturing, the environment, and various other fields. They are indispensable devices for measuring flow. Currently, research has primarily focused on gas−liquid two-phase flow within the flowmeter, giving limited attention to the impact of solid phases. In practical applications, crude oil frequently contains solid particles and other impurities, leading to equipment deformation and a subsequent reduction in measuring accuracy. This paper investigates how particle dynamic parameters affect the erosion evolution characteristics of flowmeters operating in solid−liquid two-phase conditions, employing the dynamic boundary erosion prediction method. The results indicate that the erosion range and peak erosion position on the overcurrent wall of the solid−liquid two-phase flowmeter vary with different particle dynamic parameters. Erosion mainly occurs at the contraction section of the s... [more]
Use of Non-Chlorine Sanitizers in Improving Quality and Safety of Marketed Fresh Salad Vegetables
Sharmin Zaman, Ashfaq Aziz, Md. Abubakkar Siddique, Md. Abdul Khaleque, Md. Latiful Bari
June 5, 2024 (v1)
Keywords: common fresh salad vegetables, food safety, non-chlorine sanitizer
The safety of vegetable food is compromised by various factors, including the inefficient or excessive use of sanitizers. Instances of individuals falling ill after consuming raw vegetables have been reported, with outbreaks of diseases caused by pathogens on fresh vegetables becoming increasingly prevalent globally, attracting significant media coverage and impacting the economic viability of vegetable cultivation. Measures to enhance food safety in postharvest horticultural produce involve controlling microbial proliferation and minimizing cross-contamination. Sanitizers were utilized in the food safety arsenal for a variety of purposes, including pathogen elimination and microbe reduction, hand, tool, and vegetable contact surface cleaning, and produce shelf-life extension. Choosing an appropriate sanitizer for all vegetables is difficult due to a lack of knowledge on which sanitizers are ideal for the many types of vegetables grown on farms under different environmental circumstanc... [more]
Waste-to-Energy Processes as a Municipality-Level Waste Management Strategy: A Case Study of Kočevje, Slovenia
Vladimir Prebilič, Matic Može, Iztok Golobič
June 5, 2024 (v1)
Keywords: biogas, Energy Conversion, Exergy, gas turbine, gasification, ICE, incineration, municipal solid waste, pyrolysis, steam turbine, waste management, waste utilization, waste-to-energy
The escalating challenge of waste management demands innovative strategies to mitigate environmental impacts and harness valuable resources. This study investigates waste-to-energy (WtE) technologies for municipal waste management in Kočevje, Slovenia. An analysis of available waste streams reveals substantial energy potential from mixed municipal waste, biodegradable waste, and livestock manure. Various WtE technologies, including incineration, pyrolysis, gasification, and anaerobic digestion, are compared. The results show that processing mixed municipal waste using thermochemical processes could annually yield up to 0.98 GWh of electricity, and, separately, 3.22 GWh of useable waste heat for district heating or industrial applications. Furthermore, by treating 90% of the biodegradable waste, up to 1.31 GWh of electricity and 1.76 GWh of usable waste heat could be generated annually from biodegradable municipal waste and livestock manure using anaerobic digestion and biogas combustio... [more]
Production Forecasting at Natural Gas Wells
Alina Petronela Prundurel, Ioana Gabriela Stan, Ion Pană, Cristian Nicolae Eparu, Doru Bogdan Stoica, Iuliana Veronica Ghețiu
June 5, 2024 (v1)
Keywords: forecast, gas production, Gauss and Hubbert models, Monte Carlo method, wells
In Romania, natural gas production is concentrated in two large producers, OMV Petrom and Romgaz. However, there are also smaller companies in the natural gas production area. In these companies, the deposits are mostly mature, or new deposits have low production capacity. Thus, the production forecast is very important for the continued existence of these companies. The model is based on the pressure variation in the gas reservoir, and the exponential model with production decline is currently used by gas and oil producers. Following the variation in the production of the gas wells, we found that in many cases, the Gaussian and Hubbert forecast models are more suitable for simulating the production pattern of gas wells. The models used to belong to the category of poorly conditioned models, with little data, usually called gray models. Papers published in this category are based on data collected over a period of time and provide a forecast of the model for the next period. The mathem... [more]
Oxidation Study and Mechanism Analysis of Desulfurization Ash in Dense-Phase Tower
Gang Lu, Hao Li, Hongzhi Ma, Tingshuang Leng
June 5, 2024 (v1)
Subject: Materials
Keywords: anaerobic fermentation, calcium sulfite, dense-phase tower, desulfurization ash, thermal oxidation
Dense-phase-tower desulfurization technology is an emerging semi-dry flue-gas desulfurization ash process, i.e., the flue gas is allowed to enter the desulfurization tower from the bottom up and, at the same time, is sprayed with a desulfurizing agent that undergoes an acid−base reaction with the flue gas in the ascent process. The calcium sulfite and calcium sulfate produced by the reaction and the part of the desulfurization agent that is not involved in the reaction will enter the subsequent dust removal system, and what is retained is the by-product desulfurization ash. This desulfurization ash contains a large amount of calcium sulfite, which leads to its unstable nature; it is easily oxidized and expands in volume, and, if used in the field of building materials, it will lead to cracking and other problems, so it is difficult to effectively use it. In order to solve this problem, XRF, XRD, and iodometric and other analytical methods were used to determine the specific composition... [more]
What Role Does Simulation Play in Sustainable Industrial Development?
Julia Nazarejova, Vladimir Modrak
June 5, 2024 (v1)
Subject: Environment
Keywords: economic, environmental, industry, Renewable and Sustainable Energy, Simulation
Sustainability as a concept is present in most aspects of our everyday life, and industry is no exception. Likewise, there is no doubt that the necessity to produce goods in a sustainable way and to ensure that products are sustainable is gaining more and more attention from producers, customers, governments, and various organizations. Understandably, there are several ways to increase the sustainable development of industrial production. One effective tool is simulation, which can have a significant impact on improving environmental, economic, and social sustainability. This paper explores the role of simulation as a powerful scientific and engineering solution in advancing sustainability within industrial ecosystems. Its main scope is to map the existing literature on the usage of simulation as a supportive tool for achieving this goal. For this purpose, a bibliometric analysis was conducted, allowing for tailored insights into the use of simulation in sustainable production.
Showing records 1010 to 1034 of 1190. [First] Page: 1 38 39 40 41 42 43 44 45 46 Last