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Carotenoids Recovery Enhancement by Supercritical CO2 Extraction from Tomato Using Seed Oils as Modifiers
Mihaela Popescu, Petrica Iancu, Valentin Plesu, Costin Sorin Bildea
February 21, 2023 (v1)
Keywords: carotenoids, extraction enhancement, polyunsaturated fatty acids, seed oils as modifiers, supercritical extraction technology
The food, cosmetic and pharmaceutical industries have strong demands for lycopene, the carotenoid with the highest antioxidant activity. Usually, this carotenoid is extracted from tomatoes using various extraction methods. This work aims to improve the quantity and quality of extracts from tomato slices by enhancing the recovery of the carotenoids from the solid matrix to the solvent using 20 w/w% seeds as modifiers and supercritical CO2 extraction with optimal parameters as the method. Tomato (TSM), camelina (CSM) and hemp (HSM) seeds were used as modifiers due to their quality (polyunsaturated fatty acids content of 53−72%). A solubility of ~10 mg carotenoids/100 g of oil was obtained for CSM and HSM, while, for TSM, the solubility was 28% higher (due to different compositions of long carbon chains). An increase in the extraction yield from 66.00 to 108.65 g extract/kg dried sample was obtained in the following order: TSM < HSM < CSM. Two products, an oil rich in carotenoids (2... [more]
Dynamic Modeling and Simulation of the Sulfur Combustion Furnace in Industrial Smelter
Amine Mounaam, Ahmed Bichri, Ridouane Oulhiq, Ahmed Souissi, Mohamed Salouhi, Khalid Benjelloun, Hafid Griguer
February 21, 2023 (v1)
Keywords: combustion furnace, Dynamic Modelling, process simulation, sulfur burner, sulfur oxidation, sulfuric acid
In industrial smelters, sulfuric acid is manufactured using the elemental sulfur in a series of three-unit operations: elemental sulfur oxidation, sulfur dioxide catalytic conversion, and sulfur trioxide absorption. The sulfur oxidation, which is the basic step in this process, is generally performed under a sulfur combustion furnace that ensures the production of the process gas stream, which will be the main supply stream to the other unit operations. In this paper, a dynamic model is developed based on the fundamental mass and energy balance, including the sulfur oxidation and the dynamic flow behavior aspects within the furnace. The obtained model is simulated in the Matlab/Simulink environment and data from an industrial plant were used to validate the model. The simulation results and the plant measurement comparison showed an accuracy of 96%, with a mean absolute error of 16.12 °C and a root mean square error of 23.27 °C. Afterwards, the effect of different operating conditions... [more]
Recent Advances in Lithium Extraction Using Electrode Materials of Li-Ion Battery from Brine/Seawater
Jianpeng Sun, Dongdong Liang, Xiangchao Meng, Zizhen Li
February 21, 2023 (v1)
Subject: Materials
Keywords: electrochemical, electrode materials, lithium, mechanism, systems
With the rapid development of industry, the demand for lithium resources is increasing. Traditional methods such as precipitation usually take 1−2 years, and depend on weather conditions. In addition, electrochemical lithium recovery (ELR) as a green chemical method has attracted a great deal of attention. Herein, we summarize the systems of electrochemical lithium extraction and the electrode materials of the Li-ion battery from brine/seawater. Some representative work on electrochemical lithium extraction is then introduced. Finally, we prospect the future opportunities and challenges of electrochemical lithium extraction. In all, this review explores electrochemical lithium extraction from brine/seawater in depth, with special attention to the systems and electrode of electrochemical lithium extraction, which could provide a useful guidance for reasonable electrochemical-lithium-extraction.
Technological Energy Efficiency Improvements in Glass-Production Industries and Their Future Perspectives in Italy
Alessandra Cantini, Leonardo Leoni, Saverio Ferraro, Filippo De Carlo, Chiara Martini, Fabrizio Martini, Marcello Salvio
February 21, 2023 (v1)
Keywords: energy efficiency improvements, energy savings, glass manufacturing plant, Italian companies, technology solutions
The glass industry is highly energy-intensive, consuming approximately 500−700 million GJ each year. Replacing inefficient equipment with better-performing equipment is a good strategy to reduce the energy consumption of a glass plant. Since there are many alternative solutions, the choice of which technological improvement to implement is usually difficult. Therefore, a review of solutions to reduce energy consumption in a glass plant is pivotal. The literature offers similar studies, but they are not sufficiently up-to-date and do not represent the actual state of the art, which should be updated. Thus, this paper aims to provide an updated list of alternative solutions, clustering them into different categories (e.g., the process stage). Moreover, this paper investigates the current applicability of energy-saving solutions in Italy. Specifically, a sample of 103 Italian companies is considered and the type of interventions that the companies recently implemented or that they intend... [more]
Dynamic Analysis of Extendable Hybrid Voltage Lift DC−DC Converter for DC Microgrid
Dhafer Almakhles, Divya Navamani Jayachandran, Lavanya Anbazhagan, Marwa Hannachi, Jagabar Sathik Mohamed Ali
February 21, 2023 (v1)
Keywords: dc–dc converter, high gain, hybrid, switched inductor, voltage stress, voltage-lift
This paper proposes a novel non-isolated high voltage gain dc−dc converter with a boost2 (B2) technique. The derived single-switch hybrid voltage-lift topology generates a higher voltage conversion ratio with less component counts than traditional voltage-lift converters. Furthermore, to show its superiority, the proposed topology is compared with other recent non-isolated dc−dc converters in terms of the number of power components such as inductors, capacitors, diodes, and switches. Moreover, the voltage stress across the power switch is less than the output voltage, which results in using low-rated components and reducing the converter cost. The steady-state analysis of the proposed topology is carried out with the operating modes in continuous and discontinuous conduction modes. The critical inductance for the proposed converter is derived for design considerations. Compared to the other traditional step-up converters, the stresses across the power diodes are highly reduced. The ana... [more]
Vehicle Dispatch and Route Optimization Algorithm for Demand-Responsive Transit
Deyong Guan, Xiaofang Wu, Ke Wang, Jie Zhao
February 21, 2023 (v1)
Subject: Optimization
Keywords: demand-responsive transit, LNS-genetic algorithm, route optimization, urban traffic, vehicle dispatch
Giving priority to the development of public transit is an important way to achieve efficient, convenient, safe, comfortable, economic, reliable, green and low-carbon sustainable development. In view of the highly dispersed and regular passenger flow, demand responsive transit is an important complementary means for traditional public transport to improve passenger satisfaction. However, high operating costs and low load factor will have a bad impact on the operation of public transport and reduce passenger satisfaction. In this work, firstly, by analyzing the demand frequency of historical travel stations, the stations with high demand are extracted by time periods as high probability travel points; On this basis, a dynamic vehicle dispatching optimization model is established, and the static vehicle dispatching is carried out with the goal of minimizing the running mileage of the bus system; Finally, based on the initial static route and the later real-time travel demand, the accurat... [more]
Development for Cooling Operations through a Model of Nanofluid Flow with Variable Heat Flux and Thermal Radiation
Mohammed Alrehili
February 21, 2023 (v1)
Keywords: non-linear stretching sheet, non-newtonian nanofluid, thermal radiation, variable conductivity, variable heat flux, viscous dissipation
This article discusses the flow of a non-Newtonian Carreau nanoliquid across a stretching radiative nonlinear sheet that is exposed to a variable heat flux. Analysis is done with changing thermal conductivity since it affects how heat and mass transfer occur. Nanoparticles are modelled using the Brownian motion and the thermophoresis phenomenon. The introduction of a similar solution to our challenge, as obtained by our paper, received significant attention. To create a dimensionless system, the governing partial differential equations are subjected to the mathematical model’s convenient similarity transformations after it has been developed. The numerical solution of the coupled highly nonlinear ordinary differential equations characterizing velocity, temperature and nanoparticles concentration is shown using an effective shooting approach. Additionally, all factors affecting the situation that could increase the effectiveness of cooling operations will be looked into. Results for vel... [more]
Numerical Analysis of Heat Transfer Enhancement Due to Nanoparticles under the Magnetic Field in a Solar-Driven Hydrothermal Pretreatment System
Yang Yu, Kai Wang, Yurong Zhao, Qicheng Chen, Nanhang Dong
February 21, 2023 (v1)
Subject: Materials
Keywords: heat transfer enhancement, magnetic field, microalgae, nanofluids, numerical simulation
Solar-driven hydrothermal pretreatment is an efficient approach for the pretreatment of microalgae biomass for biofuel production. In order to enhance the heat transfer, the magnetic fields effects on flow and heat transfer of nanofluids were investigated in a three-dimensional circular pipe. The magnetic fields were applied in different directions and magnetic field intensities to the flow. In this paper, Finite Volume Method was used to simulate flow and heat transfer of nanofluids under a magnetic field, and the Discrete Phase Model was selected to calculate two-phase flow, which was water mixed with metal nanoparticles. The research was also carried out with the various physical properties of nanoparticles, including the volume share of nanoparticles, particle diameter, and particle types. When the magnetic fields were applied along the X, Y, and Z directions and the intensity of magnetic fields was 0.5 T, the heat transfer coefficients of Cu-H2O nanofluids flow were increased even... [more]
Ecological Environmental Effects and Their Driving Factors of Land Use/Cover Change: The Case Study of Baiyangdian Basin, China
Boyu Xia, Linchang Zheng
February 21, 2023 (v1)
Subject: Environment
Keywords: Baiyangdian basin, eco-environmental quality index, factor detector, GeoDetector, interaction detector, land use/cover change, spatio-temporal pattern
Due to the combined effects of the natural environment, climate change and human activities, profound changes have occurred in terms of the eco-environmental effects of land use/cover change (LUCC) in the Baiyangdian basin. Therefore, based on land remote sensing monitoring data from 2000 to 2020, the Eco-environmental Quality Index (EQI) was introduced in this study to measure the eco-environmental effects of land use change in the Baiyangdian basin. Subsequently, the GeoDetector model was applied to detect the formation mechanism of the eco-environmental effects in the Baiyangdian basin from 2000 to 2020. The results of the study showed that cropland, woodland and grassland were the most widely distributed land use types in the Baiyangdian basin. The area of cropland declined the most and was mostly converted to construction land. The EQI increased slightly during the study period. The eco-environment of the mountainous areas in the western part of the basin and in Baiyangdian Lake w... [more]
A Systematic Review on Biosurfactants Contribution to the Transition to a Circular Economy
Elena Simina Lakatos, Lucian Ionel Cioca, Andrea Szilagyi, Mariana Gratiela Vladu, Roxana Mădălina Stoica, Misu Moscovici
February 21, 2023 (v1)
Subject: Environment
Keywords: Biomass, biosurfactant, circular economy, microbial conversion, Sustainability
Since they are more environmentally acceptable than their chemically synthesized counterparts, biosurfactants are used in a wide range of environmental applications. However, less research has been done on biosurfactants within the context of the circular economy, despite their theoretical potential to fulfill a number of circular economy ambitions, including closing the consumption loop, regenerating natural systems, and maintaining resource value within the system. Hence, the main objective of this review is to identify and analyze the contributions of biosurfactants to the implementation of the circular economy. A final sample of 30 papers from the Web of Science database was examined. We identified five broad categories of contributions: waste stream-derived production, combating food waste, strengthening soil health, and improving the efficiency of water resources. We concluded that, while manufacturing biosurfactants from waste streams can reduce production costs, optimizing yiel... [more]
Experimental Study on the Performance-Influencing Factors of an Aviation Heavy-Oil Two-Stroke Direct-Injection Ignition Engine
Bo Lu, Taixue Bei, Rui Liu, Na Liu, Ying Luo, Yuchen Liu
February 21, 2023 (v1)
Keywords: cold start, excess air coefficient, oil–gas interval, small load conditions, two-stroke direct-injection kerosene engine
To study the influence of control parameters under cold-start and low-load conditions on the performance of a heavy-oil, two-stroke, direct-injection, ignition engine for use in aviation, the operation of a two-stroke, direct-injection engine was studied in a bench test. The results were as follows: ① When the ambient temperature is 15 °C, the battery voltage is 12.4 V, and the peak speed of the starting motor is 1200 r/min. As the concentration factor increases, the cold-start speed increases, and the fuel consumption increases. The influence on the cold start is reduced after reaching a certain concentration. The cold-start time decreases with the increasing magnetization pulse width. The cold-start time is the shortest at an oil−gas interval of 6 ms. ② Under small-load conditions of 3000 r/min and 14% to 16% throttle, a higher ignition energy increases the engine power. Pollutant emissions are the lowest when the fuel injection is 7.5 mg and the excess air coefficient is approximate... [more]
Novel Fuzzy Measurement Alternatives and Ranking according to the Compromise Solution-Based Green Machining Optimization
G. Shanmugasundar, Tapan K. Mahanta, Robert Čep, Kanak Kalita
February 21, 2023 (v1)
Subject: Optimization
Keywords: decision making, fuzzy, machining, MCDM, process optimization
Due to the increase in the impact of different manufacturing processes on the environment, green manufacturing processes are the prime focus of many current pieces of research. In the current article, a green machining process for stainless steel and SS304 and AISI1045 steel has been optimized using newly developed Fuzzy Measurement Alternatives and Ranking according to the COmpromise Solution (F-MARCOS) method in the form of two case studies. In the first case study, nose radius, cutting speed, depth of cut, and feed rate are selected as the process parameters whereas surface roughness, consumption of electrical energy, and power factor are the outputs. In the second case study width of cut, depth of cut, feed rate, and cutting speed were the process parameters and material removal rate (MRR), active energy consumption (ACE), and surface roughness (Ra) are the response variables. The MARCOS method ranks the alternatives based on the ideal and anti-ideal solutions for the different cri... [more]
Vehicle Rescheduling with Delivery Delay Considering Perceived Waiting Cost of Heterogeneous Customers
Lirong Wu, Hang Zhang
February 21, 2023 (v1)
Keywords: delivery delay, loss aversion, perceived waiting cost, vehicle rescheduling
The original schedule may not be optimal or feasible due to delivery delay caused by disruption. To solve the vehicle rescheduling problem with delivery delay based on loss aversion in prospect theory and customer heterogeneity, a mathematical model is established to minimize the sum of distance cost and penalty cost. Next, an improved compressed annealing algorithm with heterogeneous pressure is proposed to solve the model. Finally, numerical experiments are executed on the basis of 30 classic Solomon benchmarks to test the performance of the proposed solution approach. Sensitivity tests are carried out for the customer waiting sensitivity parameter, the length of delay time, and the time when the delivery delay occurs. The computational results show that, compared to the traditional rescheduling method, the higher the degree of customer heterogeneity, the longer the length of delay time, and, the earlier the distribution delay occurs, the stronger the validity and practicability of t... [more]
Environmental Economical Dispatching of Electric−Gas Integrated Energy System Considering Hydrogen Compressed-Natural Gas
Xinhui Song, Zhengwei Qu, Jianan Kou, Yunjing Wang, Popov Maxim Georgievitch
February 21, 2023 (v1)
Subject: Environment
Keywords: electric–gas integrated energy system (EGIES), hydrogen-compressed natural gas (HCNG), power-to-hydrogen (P2H), wind power consumption
As a high-quality secondary energy, hydrogen energy has great potential in energy storage and utilization. The development of power-to-hydrogen (P2H) technology has alleviated the problem of wind curtailment and improved the coupling between the power grid and the natural gas grid. Under the premise of ensuring safety, using P2H technology to mix the produced hydrogen into the natural gas network for long-distance transmission and power generation can not only promote the development of hydrogen energy but also reduce carbon emissions. This paper presents a new model for incorporating hydrogen into natural gas pipelines. To minimize the sum of wind curtailment cost, operation cost and carbon emission cost, an electric−gas integrated energy system (EGIES) model of hydrogen-compressed natural gas (HCNG) containing P2H for power generation is constructed. Aiming at the problem of global warming caused by a lot of abandoned wind and carbon emissions, the economy and environmental protectio... [more]
Cytotoxicity and Thermal Characterization Assessment of Excipients for the Development of Innovative Lyophilized Formulations for Oncological Applications
Francesca Susa, Tania Limongi, Michela Millone, Valentina Cauda, Roberto Pisano
February 21, 2023 (v1)
Subject: Materials
Keywords: biopharmaceuticals, cytotoxicity, drug formulations, excipient, freeze-drying, lyophilization
Freeze-drying, also known as lyophilization, significantly improves the storage, stability, shelf life, and clinical translation of biopharmaceuticals. On the downside, this process faces complex challenges, i.e., the presence of freezing and drying stresses for the active compounds, the uniformity and consistency of the final products, and the efficiency and safety of the reconstituted lyophilized formulations. All these requirements can be addressed by adding specific excipients that can protect and stabilize the active ingredient during lyophilization, assisting in the formation of solid structures without interfering with the biological and/or pharmaceutical action of the reconstituted products. However, these excipients, generally considered safe and inert, could play an active role in the formulation interacting with the biological cellular machinery and promoting toxicity. Any side effects should be carefully identified and characterized to better tune any treatments in terms of... [more]
Velocity String Drainage Technology for Horizontal Gas Wells in Changbei
Wenbin Cai, Zhimin Huang, Xiangyang Mo, Huiren Zhang
February 21, 2023 (v1)
Keywords: coefficient of liquid-carrying model, DGR, horizontal gas well, setting position of velocity string, velocity string
The Changbei gas field is dominated by wells with large horizontal displacement, which have exhibited high gas production performance at an early stage of development. With the decrease in reservoir pressure, the liquid loading in the gas well is relatively high and gas production rapidly decreases. Therefore, suitable drainage measures are required to maintain stable gas production. Based on the characteristics of the unconnected oil jacket of gas wells in Changbei, a velocity string was used for drainage. A critical liquid-carrying model was established to determine the location of liquid loading in horizontal gas wells in Changbei. First, the coefficients of the liquid-carrying model were determined through theoretical analysis of the characteristics of the gas well formation. Then, the depth setting of the velocity string was analyzed. The critical liquid-carrying model was employed to calculate the liquid-carrying flow rate of each section; the calculated flow rates were compared... [more]
Numerical Investigation of the Use of Boron Nitride/Water and Conventional Nanofluids in a Microchannel Heat Sink
Fuat Kaya
February 21, 2023 (v1)
Keywords: boron nitride, Computational Fluid Dynamics, heat transfer, microchannel, nanofluid, pressure drop
The purpose of this paper is to study the effects of the use of boron nitride (BN) and other conventional nanoparticles (Al2O3, CuO and TiO2) on pressure drop and heat transfer in a microchannel. The governing equations for forced fluid flow and heat transfer were worked out by using fluent computational fluid dynamics (CFD) code. Computational results collected from fluent CFD code for Al2O3 as the nano-particle were compared with numerical values used in the literature for validation. The basis of a water-cooled (pure water, Al2O3/Water, CuO/Water, TiO2/Water and BN/Water) smooth microchannel was outlined, and then the corresponding laminar flow and heat transfer were evaluated numerically. The results from the numerical tests (NT) express good agreement with the values found in the literature. These results also indicate, through the comparison which was performed by taking the heat transfer and pressure loss parameters between BN and other widely used conventional nanoparticles (Al... [more]
Heavy Metals Exacerbate the Effect of Temperature on the Growth of Chlorella sp.: Implications on Algal Blooms and Management
Jueqiao Wang, Bin Yan, Hengchang Zhang, Lianqi Huang, Huan Wang, Qiaojuan Lan, Maoyun Yin, Zhihao Zhu, Xixi Yan, Ailing Zhu, Chuan Fu, Yan Wu
February 21, 2023 (v1)
Subject: Environment
Keywords: Chlorella sp., heavy metals, temperature, water pollution
With the accelerated urbanization and rapid development of the industrial and agricultural sectors, concern about the pollution of water environments is becoming more widespread. Algal blooms of varying sizes are becoming increasingly frequent in lakes and reservoirs; temperatures, nutrients, heavy metals, and dissolved oxygen are the factors that influence algal bloom occurrence. However, knowledge of the combined effect of heavy metals and temperature on algal growth remains limited. Thus, this study investigated how specific concentrations of heavy metals affect algal growth at different temperatures; to this end, two heavy metals were used (0.01 mg/L Pb2+ and 0.05 mg/L Cr6+) at three incubation temperatures (15, 25, and 30 °C) with the alga Chlorella sp. A higher incubation temperature contributed to a rise in soluble proteins, which promoted algal growth. The density of algal cells increased with temperature, and catalase (CAT) decreased with increasing temperature. Chlorella sp.... [more]
Ternary Inclusion Complex of Sinapic Acid with Hydroxypropyl-β-cyclodextrin and Hydrophilic Polymer Prepared by Microwave Technology
Abdul Ahad, Yousef A. Bin Jardan, Mohammad Raish, Abdullah M. Al-Mohizea, Fahad I. Al-Jenoobi
February 21, 2023 (v1)
Keywords: ABTS and nitric oxide scavenging activity, diabetes, HPMC, hydroxypropyl-β-cyclodextrin, ternary inclusion complex
Sinapic acid (SA) is a poorly water-soluble substance which could result in poor bioavailability. The aim of this study was to determine the “hydroxypropyl β-cyclodextrin (HPβCD)” solubilization of SA in the presence of the auxiliary substance hydroxypropyl methylcellulose (HPMC) and to evaluate the ternary inclusion complex prepared by microwave technology. Phase-solubility profiles showed that HPβCD exhibited the greatest solubilizing effect on SA in the presence of HPMC. The enhanced rate of SA dissolution was exhibited by a ternary complex. Outcomes of analyses such as “DSC, FTIR, NMR, and SEM” confirmed the embedding of SA into the cavity of the HPβCD and the formation of a ternary inclusion complex. The outcomes of antioxidant activity (ABTS and nitric oxide scavenging activity) demonstrated that SA ternary inclusion complex (TIC) presented strong antioxidant activity, which might be a result of the enhanced solubility of SA in the TIC prepared by microwave technology. Hence, SA-... [more]
Domestic Wastewater Treatment Using Constructed Wetland with Para Grass Combined with Sludge Adsorption, Case Study in Vietnam: An Efficient and Alternative Way
Van Thi Thanh Ho, Khang Quang Bui, Dien Vinh Le, Dung Hung Chau, Bich Ngoc Hoang, Huong Thi Pham, Anh Tuan Nguyen
February 21, 2023 (v1)
Subject: Environment
Keywords: constructed wetland, environmentally friendly, Para grass, red sludge, Wastewater
The environmental pollution due to wastewater, especially domestic wastewater, is becoming more serious. Thus, this study was performed to assess the removal of pollutants by the combination of wetland technology, specifically constructed wetland (CW), with Para grass (Brachiaria mutica) together with the adsorption of red sludge. With an organic loading rate (OLR) of 120 (kg COD/ha/day), the treatment efficiency for wastewater in this study is quite high and the concentrations of parameters in the effluent were lower than the limits established by the QCVN 14:2015/BTNMT for domestic wastewater, which indicated the feasibility of this combination. These results are expected to open the possibilities of using environmentally friendly processes for wastewater treatment in urban and industrial areas.
Optimization of Red Pigment Anthocyanin Recovery from Hibiscus sabdariffa by Subcritical Water Extraction
Dwila Nur Rizkiyah, Nicky Rahmana Putra, Zuhaili Idham, Mohd Azizi Che Yunus, Ibham Veza, Irianto Harny, Nurfadlih Syahlani, Ahmad Hazim Abdul Aziz
February 21, 2023 (v1)
Subject: Biosystems
Keywords: anthocyanin, flavonoid, phenolic, roselle, subcritical water extraction
The optimization of red pigment anthocyanin from roselle (Hibiscus sabdariffa) by subcritical water extraction (SWE) has not been the topic of a scientific investigation. Therefore, the objective of this paper was to establish the optimal parameters for obtaining the maximum yield, total anthocyanin compounds (TAC), total phenolic compounds (TPC), and total flavonoid compounds (TFC) by SWE utilizing a response surface methodology. The optimal conditions were 8.75 MPa, 393.54 K, and 4.89 mL/min, with a yield of 0.69 g/g, TAC of 927.74 mg/100 g, TPC of 39.54 mg/100 g, and TFC of 614.57 mg/100 g. High temperatures and flow rates are favorable for achieving a maximum yield. In contrast, a high temperature is suitable for obtaining high concentrations of anthocyanin, flavonoid, and phenolic compounds. This technique (SWE) recovers anthocyanin at a greater extraction rate than traditional methods; hence, SWE may be substituted for conventional methods for extracting anthocyanin.
Analyzing Energy Transfer Mechanism during Coal and Gas Protrusion in Deep Mines
Haitao Sun, Linchao Dai, Jun Lu, Jie Cao, Minghui Li
February 21, 2023 (v1)
Subject: Environment
Keywords: composite dynamic disaster, deep mines, energy transfer, gas, mining environment
Coal is the mainstay of China’s energy supply. With the gradual progress in China’s policy of phasing out backward coal production capacity, the intensive and deep mining of coal has gradually become the new norm. The current mining depth is increasing at a rate of 10~15 m/year. The high crust stress, high gas pressure, high ground temperature, and engineering disturbance stress in deep coal mines can lead to the occurrence of coal−rock−gas dynamic disasters that are complex and show the characteristics of compound dynamic disasters. It is important to understand the evolution and mechanism of deep coal and rock dynamic disasters accurately for the safe development of deep resources. To study the mechanism of occurrence and the evolution of impact−protrusion compound dynamic disasters, we herein analyzed the apparent characteristics of coal−rock−gas compound dynamic disasters in deep mines and obtained the mechanical and acoustic emission characteristics of coal−rock composites through... [more]
Dependence of the Atomic Structure of Solid Solutions in the Pd-Cu System Ordered According to the B2 Type on the Composition
Valentin M. Ievlev, Konstantin A. Solntsev, Alexander L. Vasiliev, Semen V. Gorbunov, Alexey I. Dontsov, Nataliya R. Roshan, Sergey V. Kannykin, Alexey V. Ovcharov, Bugakov V. Alexander
February 21, 2023 (v1)
Subject: Materials
Keywords: hydrogen permeability, ordering, Pd–Cu system, solid solution, structure
Owing to exceptionally high selectivity, membranes based on palladium alloys are widely used for obtaining high-purity hydrogen. An important issue for providing high hydrogen permeability of the membranes is to form the required phase composition. The structural organization of the solid solutions consisting of Cu−36.4 at .% Pd and Cu−50 at .% Pd were studied by X-ray diffraction (XRD), electron diffraction (ED), high-resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray spectroscopy (EDXS). It was found that the former composition can be ordered in the temperature range of 300−400 °C and in the heating (up to 800 °C)−cooling cycle. In the presence of excess Cu atoms (27.2%), this structure can be represented by CsCl type structural units (β-phase) and distributed body center cubic (BCC) copper structural units in the corresponding concentration dose. The formation of a single crystal ordered phase within the mosaic blocks of the disordered phase was establis... [more]
Predicting the Recovery and Nonrecoverable Compliance Behaviour of Asphalt Binders Using Artificial Neural Networks
Abdulrahman Hamid, Hassan Baaj, Mohab El-Hakim
February 21, 2023 (v1)
Keywords: ANNs model, creep, fly ash, geopolymer, glass-powder, SBS
Additives are widely used to enhance the rheological and performance properties of asphalt binder to satisfy the demands of extreme loading and climatic conditions. Meanwhile, adding to the complexity of asphalt binder behaviour that requires more time, effort, and material resources during laboratory work. The purpose of this research was to use Artificial Neural Networks (ANNs) to predict the recovery (R) and nonrecoverable compliance (Jnr) behaviour of asphalt binder based on mechanical test parameters and rheological properties of asphalt binder. A comprehensive experimental database consisting of the results of the frequency sweep and Multiple Stress Creep Recovery (MSCR) test using a dynamic shear rheometer (DSR) at five test temperatures (46 ∘C, 52 ∘C, 58 ∘C, 64 ∘C, and 70 ∘C). Prediction models for R and Jnr of asphalt binder modified with different contents of fly ash, fly ash-based geopolymer, glass powder/fly ash-based geopolymer, and styrene−butadiene styrene (SBS) were dev... [more]
Unforgeable Digital Signature Integrated into Lightweight Encryption Based on Effective ECDH for Cybersecurity Mechanism in Internet of Things
Adel A. Ahmed, Omar M. Barukab
February 21, 2023 (v1)
Keywords: digital signature, ECDH, IoT, random oracle model
Cybersecurity protocols enable several levels of protection against cyberattacks (digital attacks) that spread across network devices, platform programs, and network applications. On the Internet of Things (IoT), cyberattacks are generally intended to access and change/destroy sensitive information, which may reduce IoT benefits. Moreover, recent IoT systems are experiencing a critical challenge in designing a lightweight and robust cybersecurity mechanism on resource-constrained IoT devices. The cybersecurity challenges facing the IoT that should be taken into consideration are identifying compromised devices, data/service protection, and identifying impacted IoT users. This paper proposes an unforgeable digital signature integrated into an effective lightweight encryption (ELCD) mechanism that utilizes the secure key distribution in an elliptic curve Diffie−Hellman (ECDH) and resolves the weak bit problem in the shared secret key due to the Diffie−Hellman exchange. The ELCD mechanism... [more]
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