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Showing records 36875 to 36899 of 43292. [First] Page: 1 1472 1473 1474 1475 1476 1477 1478 1479 1480 Last
36875. LAPSE:2023.2256
Design and Optimization of γ-Shaped Settlement Training Wall Based on Numerical Simulation and CCD-Response Surface Method
February 21, 2023 (v1)
Subject: Process Design
Keywords: numerical simulation, optimal design, response surface method, the joint hub of pump station and sluice, training wall
To ameliorate the inflow state of the joint hub of a pump station and sluice, a γ-shaped settlement training wall was designed with its state adjusted automatically in line with the actual working condition of the project. The central composite design (CCD) of the response surface method was adopted to optimize the geometrical size of the training wall in the operational states of pumping and free-draining separately. The results showed that the alteration of different size factors of the γ-shaped settlement training wall had different degrees of influence on its rectification effect; the intake flow state of the joint hub of the sluice and pumping station with the γ-shaped settlement training wall can be significantly improved with the flow velocity uniformity in the inlet channel next to the junction of the sluice chamber, reaching 80.42%, and the flow velocity uniformity ahead of the sluice, reaching 84.78%, in the operational state of free-draining. By combining the results of nume... [more]
36876. LAPSE:2023.2255
An Integrated Multiple-Criteria Decision-Making Model for New Product Development: The Case of Taiwan Organic Light-Emitting Diode Industry
February 21, 2023 (v1)
Subject: Modelling and Simulations
Keywords: FANP, ISM, new product development, organic light-emitting diode
Due to the strong demand for organic light-emitting diode (OLED) display products and the highly competitive global market, OLED enterprises need to proactively make product innovations for presuming business competitive advantage, high sales, high profits, high customer consuming value, and the sustainability of the enterprise. A suitable multi-criteria decision-making (MCDM) model for OLED new product development (NPD) can help OLED enterprises’ R&D team to minimize risks and maximize the success rate of NPD. However, the literature reviews of the MCDM model for OLED NPD are very rare. This study aims to propose the approaches for establishing an integrated MCDM model for OLED NPD that apply three methodologies which include the literature review and expert panel, Interpretive structural modeling (ISM), and Fuzzy analytic network process (FANP). Meanwhile, after the implication of the proposed approaches in the case study of Taiwan OLED NPD, this study proposes an integrated MCDM mod... [more]
36877. LAPSE:2023.2254
Experimental Studies of the Processes of Stepped Torque Loads Parrying by Asynchronous Electric Drives and Interpretation of Experimental Results by Nonlinear Transfer Functions of Drives
February 21, 2023 (v1)
Subject: Energy Systems
Keywords: electric drive, hyperstability, nonlinear systems, reactions of electric drives, stepped loads, transfer function of the nonlinear link
This article presents the results of experimental studies of asynchronous motors with a short-circuited rotor (induction motors—IM) with the most common frequency control methods: scalar; vector control; vector with speed control circuit; scalar control with dynamic compensation. The purpose of the experiments was to identify and show the features of the reaction of these control methods to the stepped sketches of the load on the asynchronous electric drive, as in a nonlinear electromechanical system. When selecting the parameters and settings of the “Schneider electric” frequency converter settings, standard instructions and techniques have been used, so the settings of the regulators were not optimal. The aim was not to determine the most effective structures and show fundamentally new solutions. Asynchronous electric motors are substantially nonlinear structures. In the formation of vector control theory, a number of simplifications and assumptions were used, the cost of which was n... [more]
36878. LAPSE:2023.2253
A Review of the Preparation, Machining Performance, and Application of Fe-Based Amorphous Alloys
February 21, 2023 (v1)
Subject: Materials
Keywords: amorphous alloys, assisted machining, difficult-to-machine, Fe-based amorphous alloys
Amorphous alloy is an emerging metal material, and its unique atomic arrangement brings it the excellent properties of high strength and high hardness, and, therefore, have attracted extensive attention in the fields of electronic information and cutting-edge products. Their applications involve machining and forming, make the machining performance of amorphous alloys being a research hotspot. However, the present research on amorphous alloys and their machining performance is widely focused, especially for Fe-based amorphous alloys, and there lacks a systematic review. Therefore, in the present research, based on the properties of amorphous alloys and Fe-based amorphous alloys, the fundamental reason and improvement method of the difficult-to-machine properties of Fe-based amorphous alloys are reviewed and analyzed. Firstly, the properties of amorphous alloys are summarized, and it is found that crystallization and high temperature in machining are the main reasons for difficult-to-ma... [more]
36879. LAPSE:2023.2252
Modification of the Microstructure and Transport Properties of La2CuO4−δ Electrodes via Halogenation Routes
February 21, 2023 (v1)
Subject: Materials
Keywords: anion doping, halogenation, La2CuO4−δ, Ruddlesden–Popper, solid oxide fuel cell
Ruddlesden−Popper type electrodes with composition La2CuO4−δ are alternative cathode materials for solid oxide fuel cells (SOFCs); however, the undoped compound exhibits low electrical conductivity for potential applications, which is usually increased by alkaline-earth doping. A promising alternative to alkaline-earth doping is the modification of the anionic framework by halogen doping. In this study, La2CuO4−0.5xAx (A = F, Cl, Br; x = 0−0.3) compounds are prepared by a freeze-drying precursor method, using an anion doping strategy. The composition, structure, morphology and electrical properties are studied to evaluate their potential use in solid oxide fuel cells (SOFCs). The halogen-doped materials show higher electrical conductivity and improved electrocatalytic activity for oxygen reduction reactions when compared to the pristine material, with polarization resistance values 2.5 times lower, i.e., 0.20, 0.11 and 0.08 Ω cm2 for undoped, F- and Cl-doped samples, respectively, at 8... [more]
36880. LAPSE:2023.2251
Potential for Biomethanisation of CO2 from Anaerobic Digestion of Organic Wastes in the United Kingdom
February 21, 2023 (v1)
Subject: Energy Policy
Keywords: anaerobic digestion, biomethane production, energy security, in-situ biomethanisation, power-to-gas, United Kingdom policy
The United Kingdom (UK) has a decarbonisation strategy that includes energy from both hydrogen and biomethane. The latter comes from the growing anaerobic digestion (AD) market, which in 2020 produced 23.3 TWh of energy in the form of biogas. According to the strategy, this must be upgraded to biomethane by removal of carbon dioxide (CO2): a goal that could also be fulfilled through CO2 biomethanisation, alleviating the need for carbon capture and storage. Results are presented from a survey of publicly available datasets coupled with modelling to identify potential scale and knowledge gaps. Literature data were used to estimate maximum biomethane concentrations by feedstock type: these ranged from 79% for food wastes to 93% for livestock manures. Data from various government sources were used to estimate the overall potential for CO2 biomethanisation with current AD infrastructure. Values for the uplift in biomethane production ranged from 57% to 61%, but the need for more consistent... [more]
36881. LAPSE:2023.2250
A Healthcare Quality Assessment Model Based on Outlier Detection Algorithm
February 21, 2023 (v1)
Subject: Numerical Methods and Statistics
Keywords: Big Data, health informatics, KNN algorithm, Machine Learning, statistics
With the extremely rapid growth of data in various industries, big data is gradually recognized and valued by people. Medical big data, which can best reflect the significance of big data value, has also received attention from various parties. In Saudi Arabia, healthcare quality assessment is mostly based on human experience and basic statistical methods. In this paper, we proposed a healthcare quality assessment model based on medical big data in a region of Saudi Arabia, which integrated traditional evaluation methods and machine learning based techniques. Healthcare data has been accurate and effective after noise processing, and the outliers could reflect certain medical quality information. An improved k-nearest neighbors (KNN) algorithm has been proposed and its time complexity have been reduced to be more suitable for big data processing. An outlier indicator has been established based on statistical methods and the improved KNN algorithm. Experimental results showed that the p... [more]
36882. LAPSE:2023.2249
Sub-THz Small-Signal Equivalent Circuit Model and Parameter Extraction for 3 nm Gate-All-Around Nanosheet Transistor
February 21, 2023 (v1)
Subject: Modelling and Simulations
Keywords: full-wave electromagnetic simulation, gate-all-around field effect transistor, parameter extraction, small signal equivalent circuit model
This paper presents a novel RF small-signal equivalent circuit model and parameter extraction for 3 nm nanosheet gate-all-around field effect transistor (GAAFET). The extrinsic parasitic effect induced by ground-signal-ground (GSG) layout is evaluated by 3D full-wave electromagnetic simulation, and an improved five-step analytical parameter extraction method is proposed for such extrinsic GSG layout. The model parameters for the intrinsic device are analytically determined with the help of nonlinear rational function fitting. The accuracy of the proposed extraction method was confirmed via comparisons between device simulator and electromagnetic simulator with frequency responses up to 300 GHz. Excellent agreement is obtained between the simulated and modeled S-parameters, and the calculated error is lower than 2.689% for the extrinsic layout, and 0.897% for the intrinsic device in the whole frequency range among multi-bias points.
36883. LAPSE:2023.2248
Treatment of Sewage Sludge Compost Leachates on a Green Waste Biopile: A Case Study for an On-Site Application
February 21, 2023 (v1)
Subject: Environment
Keywords: compost, green waste, leachate treatment, reuse on site, sewage sludge
This work proposes a suitable treatment for the leachates from a sewage sludge composting process using a specific windrow (biopile). The biopile’s evolution and organic content degradation were followed for 2 months with regular leachate spraying to assess the physico-chemical and biological impacts, and determine the risk of enrichment with certain monitored pollutants. The final objective was the valorization of the biopile substrates in the composting process, while respecting the quality standards of use in a circular economy way. Classical physico-chemical parameters (pH, conductivity, dissolved organic carbon (DOC), total dissolved nitrogen (TDN), etc.) were measured in the leachates and in the water-extractable and dry-solid fractions of the biopile, and the catabolic evolution of the micro-organisms (diversity and activities), as well as the enrichment with persistent organic pollutants (POPs) (prioritized PAHs (polycyclic aromatic hydrocarbons) and PCBs (polychlorinated biphe... [more]
36884. LAPSE:2023.2247
A Hydrodynamic−Elastic Numerical Case Study of a Solar Collector with a Double Enclosure Filled with Air and Fe3O4/Water Nanofluid
February 21, 2023 (v1)
Subject: Numerical Methods and Statistics
Keywords: convection, elastic wall, Fe3O4/water nanofluid, hydrodynamic, Rayleigh number
This work deals with a numerical investigation of a hydrodynamic−elastic problem within the framework of a double enclosure solar collector technological configuration. The solar collector presents two enclosures separated by an elastic absorber wall. The upper enclosure is filled with air, whereas the lower one is filled with Fe3O4/water nanofluid. The mathematical model governing the thermal and flow behaviors of the considered nanofluid is elaborated. The effects of imposed hot temperatures, the Rayleigh number and air pressure on the nanofluid’s temperature contours, velocity magnitude distribution, temperature evolution, velocity magnitude evolution and Nusselt number evolutions are numerically investigated. The numerical results show and assess how the increase in the Rayleigh number affects convective heat transfer at the expense of the conductive one, as well as how much the Nusselt number and the nanofluid velocity magnitude and temperature are affected in a function of the im... [more]
36885. LAPSE:2023.2246
The Role of Diffusivity in Oil and Gas Industries: Fundamentals, Measurement, and Correlative Techniques
February 21, 2023 (v1)
Subject: Process Design
Keywords: atomistic approach, diffusion coefficient, mixing and driving forces, non-equilibrium thermodynamics, phenomenological approach, porous media, transport processes
The existence of various native or nonnative species/fluids, along with having more than one phase in the subsurface and within the integrated production and injection systems, generates unique challenges as the pressure, temperature, composition and time (P-T-z and t) domains exhibit multi-scale characteristics. In such systems, fluid/component mixing, whether for natural reasons or man-made reasons, is one of the most complex aspects of the behavior of the system, as inherent compositions are partially or all due to these phenomena. Any time a gradient is introduced, these systems try to converge thermodynamically to an equilibrium state while being in the disequilibrium state at scale during the transitional process. These disequilibrium states create diffusive gradients, which, in the absence of flow, control the mixing processes leading to equilibrium at a certain time scale, which could also be a function of various time and length scales associated with the system. Therefore, it... [more]
36886. LAPSE:2023.2245
Proteomics Analysis of Zygosaccharomyces mellis in Response to Sugar Stress
February 21, 2023 (v1)
Subject: Biosystems
Keywords: CRISPR/Cas9, FDH1, iTRAQ, yeasts, Zygosaccharomyces mellis
The high-osmotic-pressure environment of honey is not suitable for the survival of microorganisms, except for osmotic-tolerant fungal and bacterial spores. In this study, shotgun metagenomic sequencing technology was used to identify yeast species present in honey samples. As a result, Zygosaccharomyces spp. yeast, including Zygosaccharomyces rouxii, Z. mellis and Z. siamensis, were isolated. The intracellular trehalose and glycerin concentrations of yeast, as well as the antioxidant-related CAT, SOD and POD enzyme activities, increased under a high-glucose environment (60%, w/v). To learn more about the osmotic resistance of Z. mellis, iTRAQ-based proteomic technology was used to investigate the related molecular mechanism at the protein level, yielding 522 differentially expressed proteins, of which 303 (58.05%) were upregulated and 219 (41.95%) were downregulated. The iTRAQ data showed that the proteins involved in the pathway of the cell membrane and cell-wall synthesis, as well as... [more]
36887. LAPSE:2023.2244
A Review of Lithium-Ion Battery Thermal Runaway Modeling and Diagnosis Approaches
February 21, 2023 (v1)
Subject: Process Control
Keywords: battery modeling, fault diagnosis, internal short-circuit, lithium-ion battery, thermal runaway
Lithium-ion (Li-ion) batteries have been utilized increasingly in recent years in various applications, such as electric vehicles (EVs), electronics, and large energy storage systems due to their long lifespan, high energy density, and high-power density, among other qualities. However, there can be faults that occur internally or externally that affect battery performance which can potentially lead to serious safety concerns, such as thermal runaway. Thermal runaway is a major challenge in the Li-ion battery field due to its uncontrollable and irreversible nature, which can lead to fires and explosions, threatening the safety of the public. Therefore, thermal runaway prognosis and diagnosis are significant topics of research. To efficiently study and develop thermal runaway prognosis and diagnosis algorithms, thermal runaway modeling is also important. Li-ion battery thermal runaway modeling, prediction, and detection can help in the development of prevention and mitigation approaches... [more]
36888. LAPSE:2023.2243
Assessment of Harmonic Mitigation in V/f Drive of Induction Motor Using an ANN-Based Hybrid Power Filter for a Wheat Flour Mill
February 21, 2023 (v1)
Subject: Numerical Methods and Statistics
Keywords: active filter, artificial neural network, harmonic mitigation, hybrid power filter, modified p-q theory, variable frequency drive
Voltage/frequency (V/f) drive of a three-phase induction motor plays a crucial role in a flour mill for energy saving. Wheat consumption in India is increasing day by day, which reached 105,000 metric ton (MT) in 2021. India’s high wheat consumption and production increase flour mills. Thus, energy efficiency in a flour mill is a must in the present situation. Hence, V/f drives are widely used in flour mills. Apart from the advantages of V/f drive, electronic circuits in a drive induce harmonics in a power system. Power quality plays a vital role in a modern power system. Harmonics by V/f drive increase the current consumption, causing increased losses, cable overheating, and motor overheating, which necessitates a filter for harmonic mitigation. In this paper, an artificial neural network controller-based hybrid power filter is proposed for harmonic mitigation. A hybrid power filter (HPF) is presented to overcome the problems and achieve the active and passive power filter’s benefits.... [more]
36889. LAPSE:2023.2242
Application of Computer Microtomography and Hyperspectral Imaging to Assess the Homogeneity of the Distribution of Active Ingredients in Functional Food
February 21, 2023 (v1)
Subject: Food & Agricultural Processes
Keywords: chocolate, distribution homogeneity, image analysis, image processing
Functional foods represent one of the most intensively investigated and widely promoted areas in the food and nutrition sciences’ market today. The purpose of this work is to determine the possibility of using computed microtomography to assess the homogeneity of distribution of active pharmaceutical ingredients (vitamins K and D and calcium) throughout chocolate. Algorithms for analyzing of microtomographic images were proposed to quantify the distribution of active pharmaceutical ingredients (API) in chocolate: the Gray Level Co-Occurrence Matrix, quadtree decomposition and hyperspectral imaging. The use of the methods of analysis and processing of microtomographic images allows for a quantitative assessment of the homogeneity of the distribution of components throughout the sample, without a 3D reconstruction process. In computer microtomography analysis, it is possible to assess the distribution of those components whose density differs by at least a unit in the accepted scale of g... [more]
36890. LAPSE:2023.2241
Selection of Supply Chain Sustainability Management System by Fuzzy Additive Preference Programming Method
February 21, 2023 (v1)
Subject: Optimization
Keywords: analytic hierarchical process, decision analysis, fuzzy linear programming, multiple criteria analysis, sustainability management systems
A selection of suitable sustainability management systems (SMS) is a major part of supply chain strategies to create a competitive advantage, reduce total costs, and manage long-term sustainability. A framework and method for prioritizing supply chain SMSs are presented in this research. Analytic hierarchy process (AHP) is the most common method for alternative selection in multi-criteria decision-making (MCDM). However, complex information is mixed with ambiguity and uncertainty, which makes decision makers unable to use precise or crisp numbers, so fuzzy numbers are presented to remedy this difficulty. Therefore, this research proposes a fuzzy additive preference programming (FAPP) to select the optimum SMS for a supply chain. FAPP method can produce the unique normalized optimal priority vector of fuzzy pairwise comparison matrices for SMS selection effectively with linear constraints. The additive linear constraints can eliminate the weaknesses of existing methods and equalize the... [more]
36891. LAPSE:2023.2240
Surrogate-Assisted Multi-Objective Optimization of a Liquid Oxygen Vacuum Subcooling System Based on Ejector and Liquid Ring Pump
February 21, 2023 (v1)
Subject: Optimization
Keywords: cryogenic aerospace vehicle, many-objective optimization, Surrogate Model, vacuum subcooling system
As an important combustion aid for aerospace vehicles, subcooled liquid oxygen of high density can be used to increase loading capacity of a spacecraft. Providing a large amount of cryogenic propellant in a short time with a strict energy consumption limitation is a challenge in the design of the fuel filling system. The authors proposed a vacuumed subcooling system combined with an ejector and liquid ring pump to vacuum a liquid oxygen tank and obtain subcooled liquid oxygen. After the liquid oxygen tank is vacuumed to an intermediate pressure by the ejector, it is further vacuumed to 10 kPa using the liquid ring pump. The infinitesimal method was used to simulate the thermodynamic processes involved. Taking the ejector working fluid mass flow rate, jet pressure, intermediate pressure, initial tank liquid level, and liquid ring pump speed as optimizing variables, optimization was conducted to determine the optimal vacuuming time, remaining liquid level in the tank, pumping speed diffe... [more]
36892. LAPSE:2023.2239
Improvement of Low-Fertility Soils from a Coal Mining Subsidence Area by Immobilized Nitrogen-Fixing Bacteria
February 21, 2023 (v1)
Subject: Energy Systems
Keywords: microorganism immobilization, mining soil, nitrogen-fixing bacteria, soil improvement, zeolite
Coal mining subsidence leads to reductions in soil fertility. In order to improve soil physical and chemical properties and to promote vegetation restoration, a nitrogen-fixing bacterium named S1 was isolated from the coal mining subsidence area in the Shendong mining area, and a zeolite-immobilized nitrogen-fixing bacterium was studied to improve the soil in the subsidence area. The results show that the immobilized nitrogen-fixing bacteria can significantly improve the ammonium nitrogen and nitrate nitrogen of soil by 50 times and 0.6 times, respectively, at 20 days, and it can also improve organic matter. In pot experiments, it was found that immobilized microorganisms can improve germination rate, plant height and the dry and fresh weight of maize. The results of the above soil culture tests and pot experiments were then compared and analyzed. It was found that plants made obvious use of soil ammonium nitrogen and nitrate nitrogen, and planting the plants was conducive to increases... [more]
36893. LAPSE:2023.2238
Study on Combined Vacuum−Mechanical Defoaming Technology for Flotation Froth and Its Mechanism
February 21, 2023 (v1)
Subject: Energy Systems
Keywords: Coal, defoaming, flotation froth, vacuum
Foam is essential in the flotation process. However, the gas−liquid−solid three-phase froth produced in the flotation process has very strong stability and is difficult to burst spontaneously. The existence of these froths will reduce the transport capacity of the pulp and affect the working efficiency of subsequent processes, such as filtration of the flotation concentrate. In this study, a new defoaming device is designed by combining mechanical impact with depressurized defoaming and its defoaming mechanism is analyzed theoretically. In addition, the liquid level height and pulp overflow method are applied to characterize the defoaming efficiency of the new defoaming device. The effects of impeller structure, pressure drop, impeller rotation frequency, and aeration rate on defoaming efficiency were studied. The results show that when increasing the pressure drop, the defoaming increases, but it will also enhance the generation of bubbles. The efficiency of combined mechanical−vacuum... [more]
36894. LAPSE:2023.2237
Research on an Improved Sliding Mode Observer for Speed Estimation in Permanent Magnet Synchronous Motor
February 21, 2023 (v1)
Subject: Modelling and Simulations
Keywords: composite reaching law, inverse saturation function, permanent magnet synchronous motor (PMSM), sliding mode observer (SMO)
Aimed at the problems of system chattering and large observation errors in the sensorless control of a permanent magnet synchronous motor (PMSM) based on a traditional sliding mode observer (SMO), a combined reaching law algorithm based on the exponential reaching law and arcsine saturation function reaching law is proposed to improve the sliding mode observer. An appropriate positive real number is taken and compared with the product of controller gain and stator current observation error to judge the system position in sliding mode motion. In the early stage of sliding mode motion, the exponential reaching law is utilized, and then, in the latter and stable stages of sliding mode motion, the arcsine saturation function reaching law is used. The stability of the observer is proved by Lyapunov theory. The simulation and experimental data show that the speed error of the sliding mode observer based on the combined reaching law is reduced by 80% compared with the traditional sliding mode... [more]
36895. LAPSE:2023.2236
Experimental Study of Dynamic Mechanical Properties of Water-Saturated Coal Samples under Three-Dimensional Coupled Static−Dynamic Loadings
February 21, 2023 (v1)
Subject: Materials
Keywords: crack propagation, dynamic mechanical properties, energy dissipation, fractal dimension, split Hopkinson pressure bar (SHPB), water-saturated coal samples
It is very important to study the influence of water content on the mechanical properties of coal rock to prevent rock burst and roadway instability under dynamic disturbance. In this study, the split Hopkinson pressure bar (SHPB) test system was applied to conduct three-dimensional dynamic and static impact tests on natural and water-saturated coal samples at different strain rates to determine the dynamic mechanical properties of a series of water-bearing coal samples. Based on the new data, we discuss the strength, deformation, crushing energy dissipation, and fractal characteristics of natural and saturated coal rocks. We specifically focus on the different effects of hydraulic pressure on crack propagation under static and dynamic loads. Our results document a well-defined linear relationship between the peak stress and the strain rate of coal in the natural state and the water-saturated state. Once the impact rate reaches a certain value, a double peak phenomenon is observed, and... [more]
36896. LAPSE:2023.2235
A Capability Maturity Model for Intelligent Manufacturing in Chair Industry Enterprises
February 21, 2023 (v1)
Subject: Modelling and Simulations
Keywords: analytic network process, chair industry, comprehensive evaluation model, intelligent manufacturing, maturity assessment
Intelligent manufacturing has a strong role in promoting the transformation and upgrading of traditional industries such as the chair industry. This study aimed to accurately evaluate the production status and technical level of chair industry enterprises, and then better guide chair industry enterprises to gradually implement intelligent manufacturing. Based on the analytic network process (ANP), we propose four capability domains, nine capability sub-domains, and 21 evaluation elements, thereby constructing an evaluation model for the capability maturity of chair industry enterprises’ intelligent manufacturing. First, the weight relationship of each index of the model was determined by means of an expert questionnaire. Then, super decision software was used to complete the modeling of the evaluation index of the network analytic hierarchy process. Finally, the evaluation model of the intelligent manufacturing maturity of chair industry enterprises was applied to 50 chair industry ent... [more]
36897. LAPSE:2023.2234
Integrated Reservoir Model and Differential Stimulation Modes of Low Permeability Porous Carbonate Reservoir: A Case Study of S Reservoir in X Oilfield in Iraq
February 21, 2023 (v1)
Subject: Modelling and Simulations
Keywords: differential stimulation modes, fracturing experiments, integrated reservoir model, low-permeability carbonate rock, sweet spots classification
The S reservoir in the X Oilfield in Iraq has great development potential due to its rich geological reserves. However, the low permeability and strong heterogeneity of the reservoir lead to great differences in reservoir stimulation performance. In this study, an integrated reservoir model and differential stimulation mode are put forward to solve the above problems. First, the feasibility of fracturing is evaluated by laboratory experiments. Second, an integrated reservoir model is established, which mainly includes a rock mechanics model, fracturing simulation model, and numerical simulation model, and correct the integrated model by fracturing operation curves and production dynamic curves. Third, three types of stimulation areas are classified according to the combination of sweet spot types, and three different stimulation modes are proposed. In conclusion, a small-scale stimulation mode should be applied in the Type I area to maximize economic benefits. In the Type II area, the... [more]
36898. LAPSE:2023.2233
A Comprehensive Review of the Properties, Performance, Combustion, and Emissions of the Diesel Engine Fueled with Different Generations of Biodiesel
February 21, 2023 (v1)
Subject: Energy Systems
Keywords: biodiesel, combustion, diesel engine, emission, performance
Due to the increasing air pollution from diesel engines and the shortage of conventional fossil fuels, many experimental and numerical types of research have been carried out and published in the literature over the past few decades to find a new, sustainable, and alternative fuels. Biodiesel is an appropriate alternate solution for diesel engines because it is renewable, non-toxic, and eco-friendly. According to the European Academies Science Advisory Council, biodiesel evolution is broadly classified into four generations. This paper provides a comprehensive review of the production, properties, combustion, performance, and emission characteristics of diesel engines using different generations of biodiesel as an alternative fuel to replace fossil-based diesel and summarizes the primary feedstocks and properties of different generations of biodiesel compared with diesel. The general impression is that the use of different generations of biodiesel decreased 30% CO, 50% HC, and 70% smok... [more]
36899. LAPSE:2023.2232
Thermal Stability Determination of Propylene Glycol Sodium Alginate and Ammonium Sulfate with Calorimetry Technology
February 21, 2023 (v1)
Subject: Process Design
Keywords: differential scanning calorimetry, propylene glycol alginate, sulfonation process safety, thermogravimetric analyzer
Propylene Glycol Alginate Sodium Sulfate (PSS) is widely produced and used in medicine as a marine drug for treating hyperlipidemia. During the sulfonation synthesis of PSS, the sulfonation of chlorosulfonic acid is exothermic. At high temperatures, the process can easily produce a large amount of ammonium sulfate. Ammonium sulfate adheres to PSS in crystal and participates in the sulfonation reaction. In this study, the sulfonation process of commercial PSS was reproduced in the laboratory using chlorosulfonic acid and formamide. We used differential scanning calorimetry and thermogravimetric analyzer to examine the thermal stability of PSS, and we used both differential and integral conversional methods to determine the appropriate thermokinetic models for this substance. We also established an autocatalytic model to study the conversion limit time and the maximum rate time of this substance. After calculation, the activation energy of this substance is no more than 60 kJ/mol, and it... [more]
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