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Showing records 36850 to 36874 of 43292. [First] Page: 1 1471 1472 1473 1474 1475 1476 1477 1478 1479 Last
Numerical Simulation of Diffusion Regularity and Parameter Optimization of Shaft Grouting Slurry
Weidong Pan, Suyu Liang, Shengyou Liu, Zhining Zhao, Dashun Zha
February 21, 2023 (v1)
Keywords: diffusion regularity, infiltration grouting, numerical simulation, parameter optimization, shaft
Increase in downhole mining prompts the need to develop effective methods for maintenance of shafts. Currently, grouting behind the shaft wall is the main approach used for prevention of water seepage into the shaft. Several factors determine the grouting effect, and grouting often fails during field applications due to use of ineffective parameters. In the present study, numerical simulation was performed to evaluate slurry diffusion regularity under different grouting parameters based on the factors that affect shaft grouting. The simulation results showed that the overall diffusion radius of the slurry increased with increase in grouting time and stabilized toward the end of the simulation, under different grouting parameters. Porosity of the surrounding rock near the grouting hole gradually became denser with an increase in time, which is not conducive for diffusion of the slurry. The amount of water gushing at 146 m below the secondary shaft of Zhundong No. 2 mine decreased by 81%... [more]
Shale Gas Productivity Prediction Model Considering Time-Dependent Fracture Conductivity
Yuan Pan, Yiwen Xu, Ze Yang, Chunli Wang, Ruiquan Liao
February 21, 2023 (v1)
Keywords: fracturing horizontal wells, production prediction, shale gas, time-dependent fracture conductivity
Conventional shale gas productivity prediction techniques consider fracture conductivity to be a fixed value, but in actual production processes, conductivity changes with time. Therefore, this paper proposed a capacity prediction method that considers time-dependent conductivity and validates its accuracy using commercial simulators. First, relevant parameters were obtained by fitting the improved long-term conductivity test, and then the shale gas seepage model was established using the EDFM method. The laboratory test results showed that the order of significance affecting the conductivity retention rate was fracturing fluid viscosity > sand concentration > fracturing fluid retention time; the calculation results of the production prediction model show that the flow and the pressure curves that corresponded to constant conductivity and variable conductivity were to some extent different. In the presence of complex fractures and natural fractures, the increase in the variable conduct... [more]
Nitric Oxide-Releasing NO−Curcumin Hybrid Inhibits Colon Cancer Cell Proliferation and Induces Cell Death In Vitro
Adel Hidmi, Mahmoud Alzahayqa, Sharihan Erikat, Raghad Bahar, Lamia Hindi, Nawaf Al-Maharik, Zaidoun Salah
February 21, 2023 (v1)
Subject: Biosystems
Keywords: colon cancer, curcumin, hybrid, nitric oxide, NO
Cancer is a leading cause of death worldwide, and most of the currently available drugs for cancer treatment have limited potential. Natural products and their relatives continue to represent a very high percentage of the drugs used for cancer treatment. Curcumin is one of several natural drugs that has recently attracted much attention due to its putative cancer-preventive and anticancer properties. As well, Nitric Oxide (NO) holds a great potential for NO-based treatments for a wide variety of diseases. Here, for the first time, we tested the anti-cancer activities of an NO−Curcumin hybrid, hypothesizing that by joining the effects of curcumin and NO in one compound, the hybrid compound would be more potent than curcumin alone in treating colon cancer. To compare the anti-cancer activities of curcumin and NO−curcumin, we treated different colon cancer cell lines with either curcumin or NO−curcumin and tested their effects on cell proliferation and death. Our results show that NO−curc... [more]
Impact of Combining Tumbling and Sous-Vide Cooking Processes on the Tenderness, Cooking Losses and Colour of Bovine Meat
Konan Charles Aimeric N’Gatta, Alain Kondjoyan, Raphael Favier, Jason Sicard, Jacques Rouel, Dominique Gruffat, Pierre-Sylvain Mirade
February 21, 2023 (v1)
Keywords: beef tenderness, lightness, shear force, tumbling, vacuum cooking
This study investigated the effect of combining tumbling and sous-vide cooking processes on the tenderness, cooking losses and colour of bovine Semitendinosus (ST) muscles sampled from Charolais-breed cows. Half of the ST muscles were tumbled for 12 h with a compression rate of 40%. All muscle samples, whether tumbled or not, were then sous-vide cooked at 50 °C, 60 °C or 80 °C for 1 h or 4 h. After cooking, we measured the shear forces (SF), cooking losses, total water content and the main colour characteristics of pre-tumbled and non-tumbled meat pieces. Pre-tumbled meat pieces had 20% lower SF values than non-tumbled meat pieces, regardless of the cooking conditions applied. All meat pieces cooked at 50 °C had significantly higher (p < 0.05) SF values and lower (p < 0.05) cooking losses than meat pieces cooked at 60 °C or 80 °C. Pre-tumbled meat pieces showed significantly lower cooking losses (p < 0.001) than non-tumbled meat pieces. Applying the tumbling process before coo... [more]
Predicting the Effect of Mo Addition on Metastable Phase Equilibria and Diffusion Path of Fe in NiAl Laser-Clad Coatings Using First-Principle Calculations and CALPHAD Simulations
Chun-Ming Lin
February 21, 2023 (v1)
Keywords: computational model, diffusion mechanism, laser deposition, Mo-doped NiAl coating, phase stability
This study used first-principle calculations and CALPHAD simulations to investigate the effects of adding Mo to NiAl laser-clad coatings in terms of metastable phase equilibria and Fe diffusion path with a focus on thermodynamic phase stability and element diffusion behavior. First-principle calculations were performed using 3 × 3 × 3 supercells to determine the formation energies of NiAl and Mo-rich phases within a Mo-doped NiAl cladding layer. The findings of this analysis are consistent with the d-orbital energy and bond order results obtained using DV-Xa molecular orbital calculations and phase diagrams obtained using Thermo-Calc simulations. The results also revealed that the substitution of Ni and Al atoms for Fe and Mo in the NiAl matrix decreased the stability of the B2 structure, thereby reducing phase formation energy. DICTRA simulations were also performed to characterize the diffusion behavior of Fe from the substrate to the surface of the coating. This analysis revealed th... [more]
Experimental Study on Activated Diatomite Modified Asphalt Pavement in Deep Loess Area
Ting Du, Peng Song, Liping Liu
February 21, 2023 (v1)
Keywords: activated diatomite, asphalt modifier, experimental research, mix ratio design, road performance
In order to effectively prevent and control the rutting problem of asphalt pavement in the deep loess area of Eastern Gansu and reduce road diseases, diatomite was added into the asphalt mixture for laboratory tests. Through Marshall test and rutting test, the optimum mix proportion of the diatomite asphalt mixture, and the optimal mix amount of the diatomite in this area were determined. The pavement performance of activated diatomite asphalt pavement and SBS asphalt pavement in this area is compared and analyzed through laboratory tests and on-site road paving. The test results show that under the same ambient temperature, the activated diatomite asphalt pavement has the advantages of lower surface temperature, high stability, and low-water permeability coefficient than SBS modified asphalt pavement. In addition, by fitting the fatigue test data of these two asphalt pavements, it is found that the fatigue life of diatomite asphalt mixture is more sensitive to the change in stress lev... [more]
Novel Approaches Concerning the Numerical Modeling of Particle and Cell Separation in Microchannels: A Review
Ioannis H. Karampelas, Jenifer Gómez-Pastora
February 21, 2023 (v1)
Keywords: cell separation, microfluidics, particle separation, Simulation
The demand for precise separation of particles, cells, and other biological matter has significantly increased in recent years, leading to heightened scientific interest in this topic. More recently, due to advances in computational techniques and hardware, numerical simulations have been used to guide the design of separation devices. In this article, we establish the theoretical basis governing fluid flow and particle separation and then summarize the computational work performed in the field of particle and cell separation in the last five years with an emphasis on magnetic, dielectric, and acoustic methods. Nearly 70 articles are being reviewed and categorized depending on the type of material separated, fluid medium, software used, and experimental validation, with a brief description of some of the most notable results. Finally, further conclusions, future guidelines, and suggestions for potential improvement are highlighted.
Immobilization of an Industrial β-Glucosidase from Aspergillus fumigatus and Its Use for Cellobiose Hydrolysis
Clara Yepes, Juliana Estévez, Miguel Arroyo, Miguel Ladero
February 21, 2023 (v1)
Subject: Biosystems
Keywords: acrylic support, cellobiose hydrolysis, covalent immobilization, double competitive inhibition, kinetic model, β-glucosidase
In this study, several covalent methods of immobilization based on acrylic supports, Schiff bases and epoxides have been applied to a commercial cocktail with a high β-glucosidase activity secreted by Aspergillus fumigatus. This cocktail was preliminary compared to a commercial secretome of Aspergillus niger, which was also subjected to the aforementioned immobilization methods. Due to its higher activity, the cocktail from A. fumigatus immobilized on ReliZyme™ HA403 activated with glutaraldehyde was employed for pNPG and cellobiose hydrolysis in diverse operational conditions and at diverse enzyme loadings, showing a very high activity at high enzyme load. A kinetic model based on the Michaelis−Menten hypothesis, in which double inhibition occurs due to glucose, has been selected upon fitting it to all experimentally retrieved data with the lowest-activity immobilized enzyme. This model was compared to the one previously established for the free form of the enzyme, observing that cell... [more]
Performance Identification of a Steam Boiler Burner via Acoustic Analysis
Kayra Kurşun, Levent Özdemir, Hakan Ersoy
February 21, 2023 (v1)
Keywords: acoustics, autoregressive method, excess air coefficient, Fourier transformation, spectral analysis, steam boiler, steam trap, Yule–Walker
Almost all systems generate acoustic signals when operating or when a process is being performed. These signals contain certain data related to the operating performance of systems. In this study, acoustic data were used to study the performance and to identify the optimum operating points of natural gas burners that are used in steam boilers. The sound recordings of burners obtained under different operating conditions were examined with acoustic analysis methods. The impact of various operating parameters on acoustic values was determined using time series analysis, frequency spectrum data and then power spectral density values. When the excess air coefficient and emission and efficiency values of boilers were compared with the acoustic data, it was determined that the Yule−Walker algorithm contained distinct and explanatory values. The steam boiler and the natural gas burner within were considered a system for the analysis. Measurement results showed that operating parameters and ac... [more]
Bioremediation of Soil from Petroleum Contamination
Anna Yurievna Stepanova, Evgeny Aleksandrovich Gladkov, Ekaterina Sergeevna Osipova, Olga Victorovna Gladkova, Dmitry Viktorovich Tereshonok
February 21, 2023 (v1)
Subject: Environment
Keywords: biodegradation, biosurfactants, microbial bioremediation, rhizodegradation
Petroleum is the most common global fossil fuel. It is a complex multi-component system mainly composed of various hydrocarbons such as alkanes, cycloalkanes, mono-, bi- and polyaromatic compounds, resins and asphaltenes. In spite of humanity’s need for petroleum, it negatively affects the environment due to its toxicity. The ecological problem is especially serious at petroleum mining sites or during petroleum transportation. Since it is not possible to replace petroleum with less toxic fuel, ways to reduce the toxic impact of petroleum hydrocarbons on the environment need to be developed. This review addresses bioremediation, a biological approach to petroleum degradation, which is mainly performed by microbes. The pathways of degradation of alkanes, alkenes and aromatic hydrocarbons are presented in detail. The effects of temperature, aeration and the presence of biogenic elements on microbial degradation of petroleum are discussed. Plant−microbe interactions involved with the biore... [more]
From Foods to Chemotherapeutics: The Antioxidant Potential of Dietary Phytochemicals
Michelle A. Briggs
February 21, 2023 (v1)
Keywords: adjuvant, antioxidant, bioavailability, chemotherapeutic, dietary prevention, nonenzymatic exogenous antioxidants, phytochemicals, synergism
Food plants have been recognized for their medicinal properties for millennia, a concept supported by epidemiological studies indicating long-term health benefits for people consuming greater amounts of fruits and vegetables. As our technology and instrumentation advance, researchers have the ability to identify promising phytochemicals, and examine their potential benefits, or detriments, to human health. While results from trials investigating single chemical supplementation have sometimes produced negative health results, studies investigating the synergistic action of phytochemicals—either within our diet or as an adjuvant to radiation or chemotherapy—appear promising. Utilizing phytochemicals as synergistic agents may lower the chemotherapeutic doses needed to incur physiological results, while also using chemicals with fewer toxic effects. This review investigates a variety of plant-produced chemicals humans typically ingest, their impacts on overall health patterns, molecular me... [more]
MHD Williamson Nanofluid Fluid Flow and Heat Transfer Past a Non-Linear Stretching Sheet Implanted in a Porous Medium: Effects of Heat Generation and Viscous Dissipation
Amir Abbas, Mdi Begum Jeelani, Abeer S. Alnahdi, Asifa Ilyas
February 21, 2023 (v1)
Keywords: heat generation, heat transfer, nanofluid, porous medium, stretching surface, viscous dissipation, Williamson fluid
The present study is carried out to examine the behavior of magnetohydrodynamic Williamson nanofluid flow and heat transfer over a non-linear stretching sheet embedded in a porous medium. In the current work, the influence of heat generation and viscous dissipation has been taken into account. The considered phenomenon in the form of partial differential equations is transformed into ordinary differential equations by utilizing an appropriate similarity transformation. The reduced form is solved by using rigorous MATLAB built-in solver bvp4c. The numerical solutions for the velocity field, temperature field, and mass concentration along with the skin friction coefficient, Nusselt number, and Sherwood number are computed. The obtained solutions are shown in graphs and are discussed with physical reasoning. It is noted that by increasing Williamson fluid parameter W, the velocity decreases and concentration profile increases. It is deduced that increasing Eckert number Ec leads to a rise... [more]
EOQ Models for Imperfect Items under Time Varying Demand Rate
Yi Wen Lok, Siti Suzlin Supadi, Kok Bin Wong
February 21, 2023 (v1)
Keywords: EOQ, imperfect items, mathematical modelling, time-varying demand
In the classical Economic Order Quantity (EOQ) model, the common unrealistic assumptions are that all the purchased items are of perfect quality and the demand is constant. However, in a real-world environment, a portion of the purchased items might be damaged due to mishandling or an accident during the shipment process, and the demand rate may increase or decrease over time. Many companies are torn between repairing or replacing the imperfect items with new ones. The right decision on that options is crucial in order to guarantee that there is no shortage of stocks while at the same time not jeopardising the items’ quality and maximising the company’s profit. This paper investigates two EOQ models for imperfect quality items by assuming the demand rate varies with time. Under Policy 1, imperfect items are sent for repairs at an additional cost to the makeup margin; under Policy 2, imperfect items are replaced with equivalent quality items from a local supplier at a higher price. Two... [more]
Study on Piezomagnetic Effect of Iron Cobalt Alloy and Force Sensor
Ruichuan Li, Jilu Liu, Jikang Xu, Xinkai Ding, Yi Cheng, Qi Liu
February 21, 2023 (v1)
Subject: Environment
Keywords: magnetostriction, mathematical model of magnetic circuit, nonlinear constitutive model, piezomagnetic coefficient
Based on the nonlinear piezomagnetic equation, the piezomagnetic effect of prismatic iron-cobalt alloy is analyzed by using the ANSYS finite element simulation platform. The variation of the dynamic piezomagnetic coefficient of the iron-cobalt alloy under different bias magnetic fields and different stress was studied through simulation. Referring to the working condition of the tractor force sensor and according to the principle of magnetic circuit superposition, a piezomagnetic force sensor was designed and manufactured using iron-cobalt alloy. According to the electromagnetic theory and piezomagnetic effect, the three-dimensional model and magnetic circuit mathematical model of the sensor are established, and the system simulation model of the piezomagnetic sensor was established based on the MATLAB/Simulink module. The experimental platform of the magnetostrictive force sensor was built to verify the correctness of the simulation model, and the effects of bias magnetic field and fo... [more]
Exergy Analysis of Reactive Distillation Coupled with High-Pressure Column for the Synthesis of Dimethyl Carbonate
Mathkar A. Alharthi
February 21, 2023 (v1)
Subject: Environment
Keywords: dimethyl carbonate, exergy analysis, ProSimPlus, Reactive Distillation, thermodynamics laws
In this article, the Dimethyl Carbonate (DMC) synthesis process was investigated thermodynamically based on a well-optimized DMC system for a developed configuration, according to a real industrial plant, presented by Huang et al. Exergy analysis was performed using ProSimPlus software as an efficient process modeling and simulation environment that is uniquely capable of exergy balance computations. The key operational variables such as the reflux ratio (Rr), feed temperatures, and feed tray location were varied to explore their impact on the total irreversibilities, global intrinsic efficiency, and DMC purity. The influence of the high pressure (HP) column reflux ratio was the most effective parameter on the exergy destruction and DMC purity, which also significantly increased the duties of the HP column reboiler and condenser. The steady state results are reported in comparison with those found in the literature, and an excellent match is shown between them.
Speciation Distribution and Influencing Factors of Heavy Metals in Rhizosphere Soil of Miscanthus Floridulus in the Tailing Reservoir Area of Dabaoshan Iron Polymetallic Mine in Northern Guangdong
Jianqiao Qin, Huarong Zhao, Ming Dai, Peng Zhao, Xi Chen, Hao Liu, Baizhou Lu
February 21, 2023 (v1)
Keywords: form, heavy metals, miscanthus floridulus, rhizosphere, tailings pond
Through field investigation and experimental analysis, the forms, contents and distribution of heavy metals (Zn, Pb, Cu, Cd, Ni, Cr) in rhizosphere and non-rhizosphere soils of Miscanthus floridulus growing everywhere in Tielongwei mine pond (sample plot 1), Caoduikeng tailings pond (sample plot 2), Donghua tailings pond (sample plot 3) and Small tailings pond (sample plot 4) in Dabaoshan, Guangdong Province were studied. The results showed that the main forms and distributions of heavy metals in rhizosphere and non-rhizosphere soils are basically the same, which shows that the mineral content accounts for most of the total amount of heavy metals, while the exchange content is low. Compared with non-rhizosphere soil, the proportion of exchangeable and organic heavy metals in rhizosphere soil increased significantly, in which the proportion of organic-bound Cu increased by 53.25%, the proportion of organic-bound Cd and Pb increased by more than 17%, and the proportion of Zn increased by... [more]
Optimal Demand-Side Management Using Flat Pricing Scheme in Smart Grid
Fahad R. Albogamy, Yasir Ashfaq, Ghulam Hafeez, Sadia Murawwat, Sheraz Khan, Faheem Ali, Farrukh Aslam Khan, Khalid Rehman
February 21, 2023 (v1)
Keywords: artificial neural network, Batteries, energy forecasting, energy management, EVs, microgrid generation, Scheduling
This work proposes a framework to solve demand-side management (DSM) problem by systematically scheduling energy consumption using flat pricing scheme (FPS) in smart grid (SG). The framework includes microgrid with renewable energy sources (solar and wind), energy storage systems, electric vehicles (EVs), and building appliances like time flexible, power flexible, and base/critical appliances. For the proposed framework, we develop an ant colony optimization (ACO) algorithm, which efficiently schedules smart appliances, and EVs batteries charging/discharging with microgrid and without (W/O) microgrid under FPS to minimize energy cost, carbon emission, and peak to average ratio (PAR). An integrated technique of enhanced differential evolution (EDE) algorithm and artificial neural network (ANN) is devised to predict solar irradiance and wind speed for accurate microgrid energy estimation. To endorse the applicability of the proposed framework, simulations are conducted. Moreover, the pro... [more]
Solving the Formation and Containment Control Problem of Nonlinear Multi-Boiler Systems Based on Interval Type-2 Takagi−Sugeno Fuzzy Models
Yann-Horng Lin, Wen-Jer Chang, Cheung-Chieh Ku
February 21, 2023 (v1)
Keywords: containment control, formation control, imperfect premise matching, interval type-2 Takagi–Sugeno fuzzy model, nonlinear multi-boiler system
An interval type-2 (IT-2) fuzzy control design method is developed to solve the formation and containment problem of nonlinear multi-boiler systems. In most practical industrial systems such as airplanes, vessels, and power plants, the boiler system often exists as more than one piece of equipment. An efficient control theory based on the leader-following multi-agent system is applied to achieve the control purpose of multiple boiler systems simultaneously. Moreover, a faithful mathematical model of the nonlinear boiler system is extended to construct the multi-boiler system so that the dynamic behaviors can be accurately presented. For the control of practical multi-agent systems, the uncertainties problem, which will deteriorate the performance of the whole system greatly, must be considered. Because of this, the IT-2 Takagi−Sugeno (T−S) fuzzy model is developed to represent the nonlinear multi-boiler system with uncertainties more completely. Based on the fuzzy model, the IT-2 fuzzy... [more]
Research and Development for Cyclotron Production of 225Ac from 226Ra—The Challenges in a Country Lacking Natural Resources for Medical Applications
Tatsuya Higashi, Kotaro Nagatsu, Atsushi B Tsuji, Ming-Rong Zhang
February 21, 2023 (v1)
Subject: Materials
Keywords: 211At, 225Ac, 226Ra, targeted alpha therapy, theranostics
The high therapeutic effect of targeted radioisotope/radionuclide therapy (TRT) using α-emitters, especially 225Ac, is attracting attention worldwide. However, the only 225Ac production method that has been put into practical use is extraction from a 229Th generator derived from the nuclear fuel 233U, and it is unlikely that this method alone is able to meet future global medical demand. Development towards new 225Ac production methods is in progress. These new 225Ac production methods require the irradiation of 232Th or 226Ra using an accelerator or a nuclear reactor. Global competition has already begun in the race to secure a reliable supply of 232Th and 226Ra, as well as 229Th for the conventional production method. Japan is a “resource-poor country” that depends on foreign countries for most of its needs. As such, it is difficult for Japan to secure raw materials such as 232Th and 226Ra for medical application. In this paper, we look back on our research at the National Institutes... [more]
Comprehensive Penetration Evaluation Method in Collisions between a Supply Ship and a Semi-Submersible Platform
Yuan Xiao, Zhi Yao, Xu Zhang
February 21, 2023 (v1)
Keywords: Energy Conversion, external dynamics, internal dynamics, penetration depth, ship–platform collision
Collisions between ships and offshore platforms frequently occur, with severe consequences. Predicting the collision depth under different conditions is very important to evaluate the severity of the consequences. Considering the time-consuming numerical simulation problem and the accuracy problems of existing approximation algorithms, this paper proposes a comprehensive approach to estimating penetration depths by obtaining two collision coefficients for specific collision structures based on the partial results of numerical simulations and simplified theoretical analysis. In this study, the collision process between a supply ship with a transverse framing stern and an offshore semi-platform was first numerically simulated based on the explicit dynamic method. The changes in ship velocity, impact force, and energy conversion before and after the collision processes were obtained through numerical simulations of the collisions with different speeds and angles. Then, by combining the ex... [more]
Picking Path Planning Method of Dual Rollers Type Safflower Picking Robot Based on Improved Ant Colony Algorithm
He Zhang, Yun Ge, Chao Sun, Haifeng Zeng, Na Liu
February 21, 2023 (v1)
Keywords: ant colony algorithm, path planning, picking track, robot, safflower
Aiming at the problem of automatic path planning for the whole safflower bulbs during the operation of safflower picking robots, an improved ant colony algorithm (ACA) was proposed to plan the three-dimensional path of the safflower picking points. The shortest time and distance were taken as the overall goal of path planning to comprehensively improve the working efficiency of safflower picking robots. First, in order to shorten time, the angle induction factor was introduced to reduce the angle rotation of the end-effector. Second, in order to shorten the length of the picking path, the picking track was optimized. Finally, the design of the secondary path optimization reduced the number of picking points, which not only shortened the length of the picking path, but also shortened the picking time. The simulation results show that the path planned by the improved ACA was reduced by three picking points, shortening the total length by 74.32%, and reducing the picking time by 0.957 s.... [more]
A Value-Added Utilization Method of Sugar Production By-Products from Rice Straw: Extraction of Lignin and Evaluation of Its Antioxidant Activity
Shengming Zhang, Liangfei Ma, Shushan Gao, Chonghao Zhu, Yehong Yan, Xiaohan Liu, Longhai Li, Haitao Chen
February 21, 2023 (v1)
Keywords: antioxidant activity, ball-milling extraction, ether extraction, lignin, rice straw
To value-added utilization of the rice straw, two types of lignin were extracted from the by-products of sugar production. The ether-extracted lignin with a purity of 98.7% was extracted from the pretreatment filtrate with two times the concentrated filtrate volume of ether, where the lignin yield was 6.62 mg/g of the rice straw. The ball-milled lignin with a purity of 99.6% was extracted from the milled enzymatic hydrolysis residue with a 1,4-dioxane solution, where the revolution speed and grinding time were 300 rpm and 12 h, respectively. The yield of ball-milled lignin was 34.52 mg/g of the rice straw, which was 421.5% higher than that extracted from extract-free rice straw. In the process of rice straw pretreatment and lignin extraction, 76.43% by mass of phosphotungstic acid catalyst and approximately 98% by volume of 1,4-dioxane solution could be recycled and reused. Compared with the soda lignin extracted from papermaking black liquor, the scavenging rates of DPPH radical and A... [more]
Blockchain Development Services Provider Assessment Model for a Logistics Organizations
Nguyen Van Thanh
February 21, 2023 (v1)
Keywords: blockchain technology, fuzzy theory, logistics, MCDM model
As the global market develops along with technological advances, especially the opening of markets in developing and underdeveloped countries, the logistics industry is considered by managers to be a useful tool to link different functions of corporate strategy. Logistics is the process of planning, implementing and controlling the movement of goods or information that are related to raw materials (inputs) and final products (outputs) from the point of origin to the point of consumption in order to meet customer requirements. The logistics industry brings about many positive effects, not only for the national economy but also for creating equal business opportunities for businesses of all economic sectors. However, large companies in the logistics industry still depend on EDI or APIS to exchange secure authentication data, which increase the security of operations within the industry, but this is the cause of a lot of confusion with serious consequences on the supply chain when it is t... [more]
A Biorefinery Approach to Biodiesel Production from Castor Plants
Fabiola Sandoval-Salas, Carlos Méndez-Carreto, Graciela Ortega-Avila, Christell Barrales-Fernández, León Raúl Hernández-Ochoa, Nestor Sanchez
February 21, 2023 (v1)
Keywords: biodiesel, biorefinery, Ricinus communis
The high consumption of fossil fuels has significant environmental implications. An alternative to reduce the use of fossil fuels and develop ecological and economic processes is the bio-refinery approach. In the present study, the authors present the production of biodiesel from castor plants through a biorefinery approach. The process includes sub-processes associated with the integral use of castor plants, such as biodiesel production, oil extraction, fertilizer, and solid biomass production. Economic analyses show that producing only biodiesel is not feasible, but economic indicators (NPV, IRR, and profitability index) show it is much more feasible to establish businesses for the valorization of products and subproducts of castor plants, such as biomass densification. The internal rate return for the second scenario (E2) was 568%, whereas, for the first scenario (E1), it was not possible to obtain a return on investment.
Physical and Mechanical Characterization of a Functionalized Cotton Fabric with Nanocomposite Based on Silver Nanoparticles and Carboxymethyl Chitosan Using Green Chemistry
Linda Gabriela Quispe-Quispe, Patricia Limpe-Ramos, Carlos Alberto Arenas-Chávez, Monica Marcela Gomez, Christian R. Mejia, Aldo Alvarez-Risco, Shyla Del-Aguila-Arcentales, Jaime A. Yáñez, Corina Vera-Gonzales
February 21, 2023 (v1)
Subject: Materials
Keywords: color index, functionalized cotton fabric, functionalized fabric, nanocomposite, nanocomposite, tensile strength
Cotton is the most widely used natural fiber for textiles but its innate capacity to absorb moisture, retain oxygen, and high specific surface area make it more prone to microbial contamination, becoming an appropriate medium for the growth of bacteria and fungi. In recent years, the incorporation of silver nanoparticles in textile products has been widely used due to their broad-spectrum antibacterial activity and low toxicity towards mammalian cells. The aim of the current study is to synthesize and characterize a nanocomposite based on silver nanoparticles and carboxymethyl chitosan (AgNPs-CMC), which was utilized to provide a functional finish to cotton fabric. The scanning electron microscope (SEM) to produce a scanning transmission electron microscope (STEM) image showed that the nanocomposite presents AgNPs with a 5−20 nm size. The X-ray diffraction (XRD) analysis confirmed the presence of silver nanoparticles. The concentration of silver in the functionalized fabric was evaluat... [more]
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