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Records added in February 2023
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Showing records 1701 to 1725 of 12650. [First] Page: 65 66 67 68 69 70 71 72 73 Last
Exploring the Potential of Carbon Capture, Utilization, and Storage in Baltic Sea Region Countries: A Review of CCUS Patents from 2000 to 2022
Mayur Pal, Viltė Karaliūtė, Shruti Malik
February 27, 2023 (v1)
Keywords: Baltic Sea region countries, Carbon Capture, carbon reduction, CCUS, patents, storage, utilization
Carbon capture, utilization, and storage (CCUS) refers to technologies that capture carbon dioxide (CO2) emissions from sources such as power plants, industrial facilities, and transportation, and either store it underground or use it for beneficial purposes. CCUS can play a role in reducing greenhouse gas emissions and mitigating climate change, as CO2 is a major contributor to global warming. In the Baltic Sea region countries (BSR), patent searches from 2000 to 2020 reveal that CCUS technologies are focused on CO2 storage, monitoring, utilization, and transport. However, the adoption and deployment of these technologies has been slow due to a variety of factors, including a lack of government action on climate change, public skepticism, increasing costs, and advances in other options such as renewables and shale gas. Overall, CCUS has the potential to significantly reduce CO2 emissions and contribute to climate change mitigation efforts, but more work is needed to overcome the barri... [more]
Experimental Evaluation of Continuous In-Situ Biomethanation of CO2 in Anaerobic Digesters Fed on Sewage Sludge and Food Waste and the Influence of Hydrogen Gas−Liquid Mass Transfer
Davide Poggio, Arman Sastraatmaja, Mark Walker, Stavros Michailos, William Nimmo, Mohamed Pourkashanian
February 27, 2023 (v1)
Keywords: biogas upgrading, biomethanation, gas–liquid mass transfer, Hydrogen, in-situ
In-situ biomethanation combines conventional biogas production from the anaerobic digestion (AD) of organic matter with the addition of hydrogen to produce a higher quality biomethane gas. However, challenges surrounding its performance and control could hinder its uptake. To investigate this, an automated rig was designed and operated to study in-situ biomethanation with sewage sludge (SS) and food waste (FW) feedstocks. The effects that were experimentally investigated included the biogas recirculation rate, stirring intensity, and organic loading rate (OLR). All the results highlighted the rate-limiting effect of H2 gas−liquid mass transfer (measured kLa in the range of 43−82 day−1), which was implied by a lack of evidence of hydrogen-induced biological inhibition and a high average equilibrium hydrogen content in the biogas (a volume of 7−37%). At an OLR of 2 g VS L−1day−1, increasing biogas recirculation and mechanical stirring rates improved the methane evolution rate up to 0.17... [more]
Upscaling Porous Media Using Neural Networks: A Deep Learning Approach to Homogenization and Averaging
Mayur Pal, Pijus Makauskas, Shruti Malik
February 27, 2023 (v1)
Keywords: averaging, deep learning, homogenization, neural network (NN), neural networks, porous-media, upscaling
In recent years machine learning algorithms have been gaining momentum in resolving subsurface flow issues related to hydrocarbon flows, Carbon capture utilization and storage, hydrogen storage, geothermal flows, and enhanced oil recovery. This paper presents and attempts to solve subsurface flow problem using neural upscaling method. The neural upscaling method, described in the present work, is a machine learning approach to calculate effective properties in each grid block for subsurface flow modeling. This method is intended to be more accurate than traditional analytical upscaling methods (which are only accurate for layered or homogeneous media) and numerical upscaling methods (which are more accurate for heterogeneous media but involve higher computational cost and are dependent on boundary conditions). The neural upscaling method is based on learning from a large number of geological realizations, which allows it to account for uncertainty in geology. It is also computationally... [more]
Experimental Research and Analysis of Soil Disturbance Behavior during the Hole Drilling Process of a Hanging-Cup Transplanter by DEM
Fandi Zeng, Xuying Li, Hongbin Bai, Ji Cui, Xuening Liu, Yongzhi Zhang
February 27, 2023 (v1)
Keywords: discrete element method, hole drilling process, optimal parameter combination, soil bin test, soil disturbance behavior
This study provides a basis for designing and optimizing the key components of hanging-cup transplanters. The discrete element method, a high-speed photography test, and indoor soil bin tests were used to explore soil disturbance behavior during the hole drilling process. A comparative analysis of the discrete element method and the high-speed photography test indicated that soil particles are mainly affected by the coupled effects of the shear force and the squeezing force of the planter. The soil disturbance range in the horizontal and longitudinal sections gradually increases with the movement of the planter. The change in the soil particle velocity of the horizontal and longitudinal sections in different zones shows a trend of first increasing, then decreasing, and finally stabilizing. The velocity of soil particles in the longitudinal section varies significantly in the direction of burial. The soil in the horizontal section mainly moves to both sides when the duckbill is opened.... [more]
The Stability Study of Cefepime Hydrochloride in Various Drug Combinations
Joanna Żandarek, Żaneta Binert-Kusztal, Małgorzata Starek, Monika Dąbrowska
February 27, 2023 (v1)
Subject: Materials
Keywords: cefepime, stability testing, TLC with densitometric detection
Modern antibiotics face many obstacles, starting with the ever-increasing resistance of microorganisms directed against the antibiotic. An important problem is also the existing trend of polypharmacy. The aim of this study was to develop qualitative and quantitative conditions for the determination of cefepime-hydrochloride solution individually and in mixtures containing other substances with biological activity, such as ketoprofen, gestodene with ethinylestradiol, estradiol, caffeine, calcium ions, paracetamol, bisoprolol, acetylsalicylic acid and ibuprofen, using thin-layer chromatography combined with densitometric analysis. The influence of temperature on the stability of cefepime in these situations was investigated. Furthermore, the effect of UV radiation on the stability of the antibiotic in model drug mixtures was tested. On the basis of the dependence of changes on the concentration of cefepime over time, the order of the reaction was designated, followed by the kinetic param... [more]
Estimation of 137Cs Distribution and Recovery Using Various Types of Sorbents in the Black Sea Surface Layer
Nikolay A. Bezhin, Dmitriy A. Kremenchutskii, Evgeniy V. Slizchenko, Ol’ga N. Kozlovskaia, Iuliia G. Shibetskaia, Vitaliy V. Milyutin, Ivan G. Tananaev
February 27, 2023 (v1)
Subject: Other
Keywords: 137Cs, Black Sea, ferrocyanide sorbents, seawater, sorbents, sorption
Monitoring 137Cs in seawater is necessary for the timely detection of radioactive contamination. The possibility of sorption and the sorption efficiency of 137Cs from seawater were studied for the first time during several cruises of the R/V (research vessel) Professor Vodyanitsky using various types of sorbents based on transition metal ferrocyanides (Anfezh, Niket, Uniket, FSS, FD-M, FIC, Termoxid 35, NKF-C) and zirconium phosphate (Termoxid 3A). The influence of the seawater flow rate and volume of the sorbent used for the recovery of 137Cs was estimated. The ferrocyanide sorbents Niket, Uniket, Termoxid 35, and FIC showed the best sorption efficiency (60−100%) at a seawater flow rate of 2−4 column volumes per minute. The data obtained during three cruises on the R/V Professor Vodyanitsky were analyzed. A detailed (28 sampling points) spatial distribution of 137Cs in the Black Sea along the southern coast of Crimea was studied using the sorbents that showed the best characteristics.... [more]
Employment Effect of Structural Change in Strategic Emerging Industries
Li Liu, Cisheng Wu, Yiyan Zhu
February 27, 2023 (v1)
Subject: Environment
Keywords: employment effect, industrial structure, strategic emerging industries
Stable development of strategic emerging industries promotes its industrial transformation and upgrading, which has affected the development of not only the society and the economy but also other fields, thereby having a great impact on employment. To measure the impact of structural change of strategic emerging industries on employment in China, this paper constructs a regression equation, in which the employment of strategic emerging industries is the dependent variable, while the change direction of strategic emerging industry structure, the employment elasticity of strategic emerging industries and the change speed of industrial structure are the independent variables. The research results are as follows: (i) The change direction of strategic emerging industries is positively correlated with employment. (ii) The employment elasticity of strategic emerging industries is on the rise, and is positively correlated with employment. (iii) The speed of change of strategic emerging industr... [more]
Kiwifruit Harvesting Damage Analysis and Verification
Zixu Li, Zhi He, Wei Hao, Kai Li, Xinting Ding, Yongjie Cui
February 27, 2023 (v1)
Keywords: finite element method, harvesting robot, kiwifruit damage
In order to reduce the mechanical damage during the kiwifruit picking process, the fruit rate of the picked fruit should be improved. The mechanical properties of the epidermis and interior of the fruit during the harvesting process were studied, so as to analyze the damage principle of the fruit. Firstly, a three-dimensional model of kiwifruit was constructed by point cloud scanning, and the flesh and placenta were filled in order to become a complete kiwifruit model. The elastic modulus, failure stress, and density of the kiwifruit skin, flesh, and placenta were obtained experimentally, and the material properties of the kiwifruit model were endowed with properties. Secondly, the finite element method was used to analyze the epidermis and internal stress of the kiwifruit by simulating the two processes of grabbing kiwifruit and picking to fruit boxes. The results show that the relative error of the simulation and test of the simulated grasping of kiwifruit was 6.42%, and the simulati... [more]
Research on Uprighting Process of a Capsized Ship in Combined Wind and Wave Parameters
Dewei Pan, Zhijie Liu, Zhaoxin Zhou, Yanan Geng, Jinpeng Shang, Zhen Min, Wei Zhang
February 27, 2023 (v1)
Keywords: capsized ship, marine salvage, righting force, wave, Wind
At present, most salvage schemes are designed based on the calculation results of ship statics, which is still an empirical method. However, many projects are always affected by the wind and waves, and there is a significant difference between the force situation of ships with wind area and the calculation results of ship statistics. This paper analyzes the methods and tools of righting a capsized ship, establishes the righting force model of a capsized ship in wind and waves in accordance with floatation, stability, righting force, waves and wind, and then derives the method of longitudinal strength calculation. The floating state and stability of a capsized ship in four different sea conditions are calculated by GHS software, and three uprighting schemes are designed based on the number and position of the righting force. According to the size of the wind and waves, this paper simulates the uprighting process of the capsized hull in four cases. According to the results, it found that... [more]
NiO-MgO Prepared by the Complex-Decomposition Method as a Catalyst for Carbon Dioxide Reforming of Methane
Ying Wang, Bin Li, Yong-Shan Xiao, Zhong-Wen Liu
February 27, 2023 (v1)
Keywords: Carbon Dioxide, complex-decomposition, methane, NiO-MgO, Syngas
The NiO-MgO solid solution has been proven to be an efficient catalyst for the carbon dioxide reforming of methane (CRM). However, the challenge is still there for the facilely controlled synthesis of the single-phase solid solution with the uniform composition, and the interactions between NiO and MgO are not consistently correlated with the CRM performance. To address these issues, in this work, the complex-decomposition method was applied to regulate the chemical and structural properties of NiO-MgO catalysts via simply changing the complexing agent, calcination temperature, and Ni/Mg molar ratio. The catalysts were comparatively evaluated for CRM under severe reaction conditions of 750 °C, 0.1 MPa, CH4/CO2 = 1, and a gas hourly space velocity of 60000 mL·g−1·h−1. Irrespective of the complexing agents investigated, NiO-MgO solid solution was exclusively formed. However, the structural and reductive properties of the NiO-MgO catalysts were strongly dependent on the complexing agent,... [more]
B-LIME: An Improvement of LIME for Interpretable Deep Learning Classification of Cardiac Arrhythmia from ECG Signals
Talal A. A. Abdullah, Mohd Soperi Mohd Zahid, Waleed Ali, Shahab Ul Hassan
February 27, 2023 (v1)
Keywords: B-LIME, cardiac arrhythmia, deep learning, electrocardiogram, explanation, interpretation, LIME
Deep Learning (DL) has gained enormous popularity recently; however, it is an opaque technique that is regarded as a black box. To ensure the validity of the model’s prediction, it is necessary to explain its authenticity. A well-known locally interpretable model-agnostic explanation method (LIME) uses surrogate techniques to simulate reasonable precision and provide explanations for a given ML model. However, LIME explanations are limited to tabular, textual, and image data. They cannot be provided for signal data features that are temporally interdependent. Moreover, LIME suffers from critical problems such as instability and local fidelity that prevent its implementation in real-world environments. In this work, we propose Bootstrap-LIME (B-LIME), an improvement of LIME, to generate meaningful explanations for ECG signal data. B-LIME implies a combination of heartbeat segmentation and bootstrapping techniques to improve the model’s explainability considering the temporal dependencie... [more]
Conductive MoO3−PEDOT:PSS Composite Layer in MoO3/Au/MoO3−PEDOT:PSS Multilayer Electrode in ITO-Free Organic Solar Cells
Md Maniruzzaman, Rahim Abdur, Md Abdul Kuddus Sheikh, Son Singh, Jaegab Lee
February 27, 2023 (v1)
Keywords: conductive composite, ITO-free, MoO3, multilayer electrode, organic solar cells
The solution-processed and conductive MoO3−PEDOT:PSS (Mo−PPSS) composite layer in a MoO3/Au/MoO3−PEDOT:PSS (MoAu/Mo−PPSS) multilayer electrode in ITO-free organic solar cells (OSCs) was optimized in terms of electrical conductivity, interfacial contact quality, work function, and process wettability of the conductive composite thin film. The surface composition of the PEDOT:PSS film onto different electrodes was observed by using X-Ray Photoelectron Spectroscopy. The PEDOT:PSS-MoO3 composite protects the dissolution of individual MoO3 with PEDOT:PSS, which was confirmed by Auger Electron Spectroscopy. The UV-Visible spectroscopy showed that the photoactive layer of P3HT:PCBM absorbs in the wavelength range of 300−650 nm with the maximum absorption at 515 nm (2.40 eV). The device performance of 3.97% based on an MoAu/Mo−PPSS conductive composite electrode exhibited comparable enhancement and only 6% enhancement compared to an ITO-based electrode (3.91%). The enhancement of device effici... [more]
Characteristics of Graphene Growth at Different Temperatures from the Benzene Ring Structure in Coal Tar
Shuhan Zhao, Zhongyang Luo, Mengxiang Fang, Qinhui Wang, Jianmeng Cen
February 27, 2023 (v1)
Keywords: benzene, coal tar, low-temperature graphene growth, mechanism
A large number of aromatic substances can be found in so-called coal tar (containing >10,000 individual compounds), which is a mixture of heavy liquid fractions (dense viscous black liquor, tended to solidification) obtained after the pyrolysis of coal (solid product—coke, gas products, and light liquid products are also produced during the process). Volatile monocyclic aromatic hydrocarbons, which are naturally occurring in coal tar, can be exploited as premium raw materials for the production of graphene by chemical vapor deposition (CVD). Moreover, aromatic chemicals (compounds with benzene rings) can produce graphene at lower temperatures than other small-molecule gas feedstocks (for graphene growth via methane gas, the temperature must be at least 900 °C). The intermediate reaction mechanism involved in the creation of graphene from various temperature ranges of monocyclic aromatic hydrocarbons in benzene ring structures has long been a fascinating enigma. Accordingly, in this pap... [more]
Progresses of the Influencing Factors and Detection Methods of Domoic Acid
Aoao Yang, Haiguang Zhang, Yu Yang, Zhaoyu Jiang
February 27, 2023 (v1)
Subject: Materials
Keywords: affecting factors, domoic acid, neurotoxicity, Pseudo-nitzschia, toxin detection
Domoic acid (DA) is a neurotoxin mainly produced by Pseudo-nitzschia diatom, which belongs to the genera Rhomboida. It can combine with the receptors of glutamate of neurotransmitters, then affecting the normal nerve signal transmission of the organism and causing nervous system disorders. However, as a natural marine drug, DA can also be used for pest prevention and control. Although the distribution of DA in the world has already been reported in the previous reviews, the time and location of its first discovery and the specific information are not complete. Therefore, the review systematically summarizes the first reported situation of DA in various countries (including species, discovery time, and collection location). Furthermore, we update and analyze the factors affecting DA production, including phytoplankton species, growth stages, bacteria, nutrient availability, trace metals, and so on. These factors may indirectly affect the growth environment or directly affect the physiol... [more]
A Semi-Analytical Model for Gas−Water Two-Phase Productivity Prediction of Carbonate Gas Reservoirs
Dayong Chen, Zheng Sun
February 27, 2023 (v1)
Subject: Materials
Keywords: carbonate gas reservoir, gas–water two-phase, semi-analytical model, stress sensitivity
The productivity prediction of gas wells in carbonate gas reservoirs is greatly affected by the characteristics of gas−water two-phase flow and fracture seepage parameters. Compared with numerical simulation, the productivity prediction based on the analytical model is fast and widely used, but the traditional analytical model is fairly simplified while dealing with the nonlinear problem of the two-phase seepage equation, leading to a large discrepancy in the results of dynamic analysis. To solve this problem, this paper considers the characteristics of gas−water two-phase flow in the reservoir and fracture, uses the dual-medium model to characterize the stress sensitivity of the fracture and reservoir, and establishes a gas−water two-phase productivity prediction model for carbonate gas reservoirs. Combining the flowing material balance equation with the Newton iteration method, the nonlinear parameters of the percolation model are updated step by step with the use of average formatio... [more]
The Prospects of Algae-Derived Vitamins and Their Precursors for Sustainable Cosmeceuticals
Neha Arora, George P. Philippidis
February 27, 2023 (v1)
Subject: Biosystems
Keywords: algae, bioactive compounds, skin treatment, vitamins
Aquatic algae are a rich source of a wide range of bioproducts intended to compete for a sizable global market share. Thanks to the gradual shift towards the use of natural products, microalgae-derived bioactive compounds offer an ecofriendly and vegan option to the cosmeceutical sector, whose products aim to improve skin health but currently consist of mostly synthetic chemicals. In particular, algae-derived vitamins and their precursors are being explored and widely used in the cosmeceuticals industry as compounds that contain biologically active ingredients with therapeutic benefits. The present review highlights the current strategies for industrial production of an array of vitamins from algae for cosmeceutical applications. When compared to traditional plant sources, algae have been found to accumulate vitamins, such as A, B1, B2, B6, B12, C and E, in high concentrations. The purpose of this review is to provide context for the development of a green and sustainable algae-derived... [more]
Thermal-Imaging-Based PCA Method for Monitoring Process Temperature
Zhijiang Lou, Weichen Hao, Shan Lu, Pei Sun, Yonghui Wang, Syamsunur Deprizon
February 27, 2023 (v1)
Keywords: fault detection and diagnosis (FDD), infrared thermal imaging, principal components analysis (PCA), spatial information-based PCA (SIPCA)
To overcome the shortage of traditional temperature sensors, this paper adopts infrared thermal imaging technology for temperature measurement. To avoid the spatial information loss issue during the image data vectorization process, this paper adopted the spatial relationship between pixels in principal component analysis (PCA) model training, which is called spatial information-based PCA (SIPCA). Then, spatial information is also used in the fault localization method to enhance the fault location performance. Tested by an experimental tank system, the proposed method achieves better performance than the traditional PCA approach, and it can detect heat leakage faults on the surface of the equipment.
A Review on Antimicrobial Packaging for Extending the Shelf Life of Food
Tobi Fadiji, Mahdi Rashvand, Michael O. Daramola, Samuel A. Iwarere
February 27, 2023 (v1)
Keywords: active packaging, antimicrobial agent, food packaging, fruit and vegetables, meat products, shelf life
Food packaging systems are continually impacted by the growing demand for minimally processed foods, changing eating habits, and food safety risks. Minimally processed foods are prone to the growth of harmful microbes, compromising quality and safety. As a result, the need for improved food shelf life and protection against foodborne diseases alongside consumer preference for minimally processed foods with no or lesser synthetic additives foster the development of innovative technologies such as antimicrobial packaging. It is a form of active packaging that can release antimicrobial substances to suppress the activities of specific microorganisms, thereby improving food quality and safety during long-term storage. However, antimicrobial packaging continues to be a very challenging technology. This study highlights antimicrobial packaging concepts, providing different antimicrobial substances used in food packaging. We review various types of antimicrobial systems. Emphasis is given to... [more]
Design, Development, and Performance Evaluation of a New Photovoltaic-Thermal (PVT) Air Collector: From Lab Testing to Field Measurements
Raquel Simón-Allué, Raúl Villén, Gonzalo Brun, Yolanda Lara, Isabel Guedea
February 27, 2023 (v1)
Keywords: air collectors, experimental testing, photovoltaic-thermal
Over the last decade, the market has experienced a growing interest in hybrid photovoltaic-thermal (PVT) technologies, although more long-term studies are needed before air-based PVT panels are fully implemented. In this paper, we present the experimental framework developed around an air-based PVT collector, consisting of a high-quality photovoltaic laminate and a newly designed thermal absorber. The experimental performance of the collector was measured both in lab testing and in a pilot plant during one of the field operations. Results show an almost constant electrical performance of 15−19%, and a thermal performance that changes a lot, ranged between 15−52% for the individual panel and 11−35% for the system of 2.5 panels in series (to maximize output temperature). Field operation presents average thermal and electrical efficiencies ranged between 16−20% with an electrical−thermal generation ratio close to 1:1.
A Low-Cost Drive and Detection Scheme for Electrowetting Display
Zhijie Luo, Cuiling Peng, Yujie Liu, Baoqiang Liu, Guofu Zhou, Shuangyin Liu, Ningxia Chen
February 27, 2023 (v1)
Keywords: defects detection, electrowetting display, machine vision, oil motion
The electrowetting display (EWD) has obtained much attention as its readability in sunlight and flexible displays. Oil motion control is an important factor for the display performance of EWD. In this paper, we propose a low-cost drive and detection scheme for EWD. The dynamic drive and detection scheme for EWD consists of a low-cost camera, computer and graphical detection system, and portable driving control system. The proposed scheme can detect oil leaking, splitting, and non-recovered defects successfully. Moreover, surface defects such as the hydrophobic layer burned and scratch can also be captured and analyzed by the proposed scheme. We hope that this scheme can provide a drive and detection platform for other EWD researchers.
Evaluation of Babassu Cake Generated in the Extraction of the Oil as Feedstock for Biofuel Production
Chastryane Silva, Bruna Sousa, João Nunes, Jackson Malveira, Rosali Marques, Luana Damasceno, Emanuelle Braga, Tassio Lessa, Luciana Bertini, Maria Maciel, Maria Rios
February 27, 2023 (v1)
Keywords: bioenergy, carbonization, carnauba, cashew nutshell, solid fuels, sugarcane bagasse
The growing demand for energy and the concern about environmental impacts reinforce the necessity for renewable energy sources such as biofuels. In this study, cake generated in the babassu oil extraction was evaluated as a potential feedstock for solid biofuel production, and it contains a blend of cashew nutshell, sugarcane bagasse, carnauba straw, and carnauba stalk. All samples were characterized by proximate analysis and Higher Heating Value. Carbonization was used to improve energy performance and compaction to understand the mechanism and the characteristics of the biomasses compacted. In the extraction of babassu oil, fresh and aged (90 days) kernel samples were used. The fresh samples reached a yield of 59.8%, and the aged samples reached a yield of 70.66%. The carbonization of babassu cake was carried out in a Muffle furnace at temperatures of 250, 300, 350, and 400 °C. The fresh babassu cake showed an HHV of 23.06 MJ kg−1 and after carbonization of 28.07 (250 °C), 30.69 (300... [more]
Numerical Analysis of Cracking Processes in RC Beams without Transverse Reinforcement
Piotr Smarzewski, Marta Słowik
February 27, 2023 (v1)
Keywords: cracks distribution, numerical analysis, reinforced concrete beams
The procedure of FEM calculations was presented in the paper. The numerical calculations concerned a simulation of crack distribution and propagation in concrete beams reinforced longitudinally without shear reinforcement. The analysis of the obtained FEM results showed different modes of failure in the beams when shear span-to-depth ratio was a/d = 2.5 and a/d = 1.8. In the analyzed beams, the ratio of longitudinal reinforcement and the mechanical properties of the steel bars were also changing parameters. The FEM results have showed that the shear failure of reinforced concrete beams without transverse reinforcement significantly depends on the ratio and yield strength of longitudinal steel bars. Furthermore, the results of numerical calculation for the beams of a/d = 2.5 were also juxtaposed with experiments performed by the author on two longitudinally reinforced concrete beams.
Study of Scavenging and Combustion Processes for Small Two-Stroke Aviation Heavy Fuel Direct Injection Engines
Longtao Shao, Yu Zhou, Shuai Zhao, Tao Yu, Kun Zhu, Shuiting Ding, Zheng Xu
February 27, 2023 (v1)
Keywords: combustion characteristics, cross scavenging, direct injection, evaporation characteristic, small two-stroke aviation piston engines
Heavy-fuel aviation piston engines (HF-APEs) are widely used in general aviation and unmanned aerial vehicle (UAV) due to their safety and fuel economy. This paper describes a numerical and experimental study of scavenging and combustion processes on a 2-Stroke Direct Injected HF-APEs for light aircraft, with its cylinder specifically designed as cross scavenging. A 3-Dimentional transient model of in-cylinder flow and combustion process is established by the Forte platform, and the engine test system is set up. By comparing the simulation results to the experimental results, it showed that multi-ports cross scavenging can generate unbalanced aerodynamic torque in the cylinder. In the compression process, the swirl ratio (SR) gradually increases, and the peak SR reaches 15. Moreover, approximately 25% of exhaust residual gas in the cylinder is conducive to the fuel atomization and evaporation process in a high-altitude environment. When the injection timing is between −8 °CA and −16 °C... [more]
Assessment of the Explosion Accident Risk in Non-Coal Mining by Hasse Diagram Technique
Xiaobin Dong, Zhen Yang, Li Guo, Yuan Gao
February 27, 2023 (v1)
Keywords: explosion accident, Hasse diagram technique, non-coal mines, Poset decision-making, risk analysis
The aim of is paper is to address the problem of identifying critical factors in the analysis of non-coal mine explosion accidents as well as to improve the rationality and accuracy of the risk analysis results. Hence, we developed a risk identification method for non-coal mine explosion accidents, combining the Systems-Theoretic Accident Model and Process (STAMP) and the Rank-order Centroid (ROC) method based on the Poset decision-making theory. The proposed method was applied to identify risk in engineering cases. Findings showed that four main dangerous events (out of twelve identified ones) were the primary culprits of related accidents, which were the events “Blasters without licenses and illegal operation” at the basic level, the event of “the confusion about the safety management system of non-coal mine companies” at the control level, and the event of “the failure about the emergency management departments” and “public security departments” at the supervision level. The approxi... [more]
Adsorption of As and Pb by Stone Powder/Chitosan/Maghemite Composite Beads (SCM Beads): Kinetics and Column Study
Gunho Song, Sanghwa Oh
February 27, 2023 (v1)
Subject: Materials
Keywords: adsorption kinetics, arsenic, column study, lead, SCM bead
Adsorption kinetics of As and Pb onto composite beads synthesized with stone powder, chitosan, and maghemite (SCM beads) with weight ratio of 1:1:0.5 were investigated in batch mode. Several kinetic models such as pseudo-first order kinetic model (PFOKM), pseudo-second order kinetic model (PSOKM), two compartment first order kinetic model (TCFOKM), and modified two compartment first order kinetic model (MTCFOKM) were utilized to analyze the kinetics. Although the beads had low specific surface area and pore volume, MTCFOKM, one of two compartment models, could predict the most accurately because the As and Pb were adsorbed onto at least two kinds of adsorption sites such as functional groups in chitosan and Fe in maghemite. In MTCFOKM, both the fast adsorption fraction (f1’) and the fast adsorption constant (k1’) for Pb were higher than those for As. Therefore, the equilibrium time (teq) for Pb adsorption was shorter than that for As adsorption, indicating that Pb adsorption was more a... [more]
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