Browse
Subjects
Records with Subject: Materials
Showing records 1 to 25 of 4403. [First] Page: 1 2 3 4 5 Last
Adsorption of Pesticides on Activated Carbons from Peach Stones
Souha Harabi, Sami Guiza, Ariadna Álvarez-Montero, Almudena Gómez-Avilés, Mohamed Bagané, Carolina Belver, Jorge Bedia
June 21, 2024 (v1)
Subject: Materials
Keywords: 2,4-dichlorophenoxyacetic acid, activated carbon, Adsorption, carbofuran, isotherms, kinetics, pesticides
This study analyzes the adsorption of two model pesticides, namely, 2,4-dichlorophenoxyacetic acid (2,4-D) and carbofuran on activated carbons obtained by chemical activation with phosphoric acid of peach stones. The effect of the synthesis conditions on the surface area development was analyzed. The highest surface area was obtained with an impregnation time of 5 h, an impregnation ratio equal to 3.5, an activation temperature of 400 °C, and 4.5 h of activation time. Under these conditions, the maximum specific surface area was equal to 1182 m2·g−1 which confirms the high porosity of the activated carbon, predominantly in the form of micropores. The surface chemistry of this activated carbon was also characterized using pH at point of zero charge, scanning electron microscopy, and Fourier transform infrared spectroscopy. Both kinetics and equilibrium adsorption tests were performed. Adsorption kinetics confirmed that 2,4-D adsorption follows a pseudo first-order adsorption kinetic mod... [more]
Investigating the Influencing Factors of Imbibition of Fracturing Fluids in Tight Reservoirs
Jian Liu, Xuefeng Qu, Jiwei Wang, Qiang Liu, Lei Zhang, Tao Huang, Haiyang Yu
June 21, 2024 (v1)
Subject: Materials
Keywords: fracturing fluids, matrix permeability, pressure, temperature, tight reservoir
Tight reservoirs are the focus of unconventional oil and gas resource development, but most tight reservoirs exhibit complex pore structures, strong non-homogeneity, and limited water drive development. Fracturing fluid imbibition is a critically important way to improve the recovery of tight reservoirs. In this paper, an NMR experimental device was used to conduct imbibition experiments in tight reservoirs, and the relationship between temperature, pressure, matrix permeability, and imbibition recovery was investigated. Based on the fracturing fluid imbibition recovery curve, the imbibition process is divided into the fast imbibition stage, slow imbibition stage, and imbibition equilibrium. In addition, based on the pore structure division, the recovery changes of each pore under different experimental conditions were quantitatively analyzed. The results indicate that the highest imbibition recovery is achieved at an experimental pressure of 5 MPa within the range of 0 MPa to 15 MPa.... [more]
Experimental Study on Chrome Tanned Leather Shavings Modification—Properties and Prospective for Future Application
Dorota Gendaszewska, Paulina Pipiak, Dorota Wieczorek, Katarzyna Sieczyńska
June 21, 2024 (v1)
Subject: Materials
Keywords: chrome tanned leather shavings, FTIR analysis, heavy metal, phytotests
Chrome tanned leather shavings (CTLS) are considered one of the more difficult wastes to manage in the tanning industry. At the same time, this waste is an important source of good quality collagen. The few methods described in the literature for the valorization of these wastes usually require pre-treatment or activation. In this study, an attempt was made to see if raw chrome tanned leather shavings (CTLS) could be modified to obtain secondary raw materials with new physical properties. Glutaraldehyde, glycerol, EDCs, pectin, and tannins were selected for modification of the CTLS. The effectiveness of the processes carried out was confirmed by FTIR analysis of the materials obtained. Changes in the intensity of the characteristic collagen peak (amide I, amide II, and amide III) and changes in the position of the bands in the 1200−1000 cm−1 region were observed in the recorded spectra. The modifications introduced confirmed changes in the physical properties of samples M1−M5, includin... [more]
Preparation of Crust Type Dust Suppression Gel Based on Plant Extraction Technology for Ginkgo biloba Leaves: Characterization, Properties, and Function Mechanism
Bo Ren, Gang Zhou, Mingkun Song, Bingyou Jiang, Yuannan Zheng, Tao Fan, Shuailong Li, Jing Zhao, Haoyang Li, Hongrui Qu
June 21, 2024 (v1)
Subject: Materials
Keywords: crust type, dust suppression materials, Ginkgo biloba leaves, molecular dynamics simulation, waste utilization
The coal industry plays an essential role in China’s economic development, and issues such as occupational health and environmental pollution caused by coal dust have attracted a great deal of attention. In accordance with the principles of environmental protection and waste management, this study used carboxymethyl ginkgo cellulose (CL) extracted and modified from Ginkgo biloba leaves as a matrix, and a graft copolymerized with sodium 3-allyloxy-1-hydroxy-1-propanesulfonate (AHPS) and N-isopropylacrylamide (NIPAM) monomers to prepare low-cost, environmentally friendly, and high-performance coal dust suppression (C-A-N). By optimizing fitting experimental data through three factors and two response surface analyses, the optimal dust suppression efficiency ratio was determined to be 4:8:5, and its swelling and water retention properties were analyzed. The microstructure, chemical reaction process, combustion performance and crusting property of the dust suppression gel were analyzed usi... [more]
Numerical Study of a Heat Exchanger with a Rotating Tube Using Nanofluids under Transitional Flow
Mohamed A. El-Magid Mohamed, Andrés Meana-Fernández, Juan M. González-Caballín, Anthony Bowman, Antonio José Gutiérrez-Trashorras
June 21, 2024 (v1)
Subject: Materials
Keywords: concentric tube, heat transfer, hybrid nanofluids, NTU, single-phase flow
Improvements in heat exchanger thermal efficiency are crucial for achieving energy use and cost reductions. The use of nanofluids and the rotation of the exchanger inner tube may enhance heat transfer and exchanger efficiency. In this work, after having performed experiments on such a heat exchanger, a three dimensional numerical model was developed to simulate the transitional forced convection flow of a horizontal double-tube heat exchanger, with the aim of obtaining insight into the effects of the inner tube rotation, fluid flow rate and type of nanofluid employed. It was found that an increase in the nanoparticle concentration up to 3% increased the exchanger efficiency. Al2O3, Al2O3-Cu and Cu-water nanofluids were studied, with the Cu-water being the fluid with the best performance (19.33% improvement). Heat transfer was enhanced with inner tube rotation up to 500 rpm (41.2%). Nevertheless, pressure drop and friction values were increased due to both phenomena, leading to higher p... [more]
Effect of Choice of Drilling Kinematic System on Cylindricity Deviation, Roundness Deviation, Diameter Error and Surface Roughness of Holes in Brass Alloy
Mateusz Bronis, Bartlomiej Krawczyk, Stanislaw Legutko
June 21, 2024 (v1)
Subject: Materials
Keywords: ANOVA, brass alloy, drilling, Grey Relational Analysis, hole quality, kinematic system, surface texture
This article presents the results of an experimental study on the effect of the selection of kinematic system for the drilling process on the cylindricity deviation, roundness deviation, diameter error and surface roughness of holes in brass alloy. Three different kinematic systems based on the dependence of the direction of rotation of the workpiece and the drill bit were used. The drill bit was mounted in an axially driven holder that allowed it to be put into motion. Cutting tests were conducted at three different spindle speeds and three different feed rates per revolution (27 tests in total). A static ANOVA analysis was used to evaluate the effect of each input parameter on each output parameter. The results of this work have practical applications in machining. The following input parameters of the drilling process should be used to obtain the smallest values of each output parameter: for CYL, n = 4775 rpm, fn = 0.14 mm/rev and KIN III; for RON, n = 4775 rpm, fn = 0.1 or 0.12 mm/... [more]
Hydrothermal Carbonization of Waste Biomass: A Review of Hydrochar Preparation and Environmental Application
Jelena Petrović, Marija Ercegović, Marija Simić, Marija Koprivica, Jelena Dimitrijević, Aleksandar Jovanović, Jovana Janković Pantić
June 21, 2024 (v1)
Subject: Materials
Keywords: adsorbents, biofuel, carbon materials, hydrothermal carbonization, waste biomass
The concept of a bio-based economy has been adopted by many advanced countries around the world, and thermochemical conversion of waste biomass is recognized as the most effective approach to achieve this objective. Recent studies indicate that hydrothermal carbonization (HTC) is a promising method for the conversion of waste biomass towards novel carbonaceous materials known as hydrochars. This cost-effective and eco-friendly process operates at moderate temperatures (180−280 °C) and uses water as a reaction medium. HTC has been successfully applied to a wide range of waste materials, including lignocellulose biomass, sewage sludge, algae, and municipal solid waste, generating desirable carbonaceous products. This review provides an overview of the key HTC process parameters, as well as the physical and chemical properties of the obtained hydrochar. It also explores potential applications of produced materials and highlights the modification and functionalization techniques that can t... [more]
Predictive Quality Analytics of Surface Roughness in Turning Operation Using Polynomial and Artificial Neural Network Models
Peter Bober, Kristína Zgodavová, Miroslav Čička, Mária Mihaliková, Jozef Brindza
June 21, 2024 (v1)
Subject: Materials
Keywords: AISI 304, AISI 304L, artificial neural network, finish turning, food processing equipment, Machine Learning, predictive quality, small batch, surface roughness
The variability of the material properties of steel from different suppliers causes problems in achieving the required surface quality after turning. Therefore, the manufacturer needs to estimate the resulting quality before starting production, especially if it is an expensive, small-batch production from stainless steel. Predictive models will make it possible to estimate the surface roughness from the mechanical properties of steel and thus support decision making about supplier selection or acceptance of a material supply. This research presents a step-by-step decision-making procedure, which enables the trained staff to make quick decisions based on commonly available information in the Mill Test Certificate (MTC). A new multivariate second-order polynomial model and feedforward backpropagation artificial neural network (ANN) models have been developed using input variables from the MTC: Tensile Strength, Yield Strength, Elongation, and Hardness. Models were used to enhance the me... [more]
Study on Influencing Factors of Nicotinamide Transdermal Absorption In Vitro and the Establishment of an Evaluation Method
Wanping Zhang, Xuefang Shi, Shilian Zheng
June 21, 2024 (v1)
Subject: Materials
Keywords: cumulative permeability, Franz diffusion cell, nicotinamide, transdermal absorption
The goal of this research was to study the factors influencing the in vitro transdermal penetration of nicotinamide and to establish an evaluation method for the in vitro transdermal absorption of nicotinamide. The permeability of nicotinamide was investigated with Franz diffusion cell in vitro transcutaneous assays, and the effect of the receiving solution composition, receiving solution pH, skin type, diffusion cell temperature, active ingredient concentration, supply quantity, and product dosage form on its permeation was investigated separately by high-performance liquid chromatography. The best assay for the transdermal absorption of nicotinamide was established—there was a better transdermal absorption performance, more stable system, better applicability, and better reproducibility when the receiving solution was PBS (phosphate-buffered saline) solution, the pH was 7.4, the membrane was pig ear skin, the temperature was 37 °C, the concentration of nicotinamide was 3%, and the do... [more]
Assessment of Microsilica as a Raw Material for Obtaining Mullite−Silica Refractories
Bagdaulet Kenzhaliyev, Alla Biryukova, Tolebi Dzhienalyev, Alexander Panichkin, Akerke Imbarova, Alma Uskenbaeva, Abdul Hafidz Yusoff
June 21, 2024 (v1)
Subject: Materials
Keywords: alumina, aluminosilicates, microsilica, mullite, mullite–silica refractory, porosity, refractory clay, strength, structure
The possibility of using microsilica in the production of mullite−silica refractories was assessed. The chemical and mineralogical compositions of the raw materials, refractory Arkalyk clay and microsilica, were studied. It has been found that primary mullite and quartz formation occurs due to dehydration of kaolinite with the formation of intermediate metakaolinite. The introduction of alumina and microsilica into the charge composition promotes the formation of secondary mullite due to the interaction of aluminum oxide and highly dispersed chemically active microsilica. Free silica in compositions undergoes polymorphic transformations with the formation of cristobalite and tridymite. Mullite−silica refractories with an open porosity of 21%, a compressive strength of 42 MPa, and a thermal deformation temperature under the load of 0.2 MPa−1350 °C were obtained.
Energy Recovery Efficiency of Integrating Anaerobic Co-Digestion of Pig Slurry and Feedlot Cattle Manure and Hydrothermal Carbonization of Anaerobic Sludge Cake
Jun-Hyeong Lee, Young-Man Yoon
June 21, 2024 (v1)
Subject: Materials
Keywords: anaerobic co-digestion, bioenergy recovery, feedlot cattle manure, hydrothermal carbonization, pig slurry
Hydrothermal carbonization (HTC) is a technology designed to improve the efficiency of bioenergy recovery by subjecting biomass to high-temperature and high-pressure conditions. By integrating this technical feature with anaerobic digestion (AD), enhanced energy recovery efficiency is achieved in treating anaerobic digestate (AD-T). The study investigates enhancing bioenergy recovery efficiency through an integrated process, combining AD of livestock manure and HTC. The primary objective is to improve the energy conversion efficiency of biomass characterized by varying solid contents and chemical compositions. Shortening the hydraulic retention time (HRT) in AD of livestock manure resulted in decreased degradation rate efficiency within the AD-T. This led to increased solid material accumulation, which was crucial for the subsequent HTC reaction. The HTC reaction exhibited its maximum bioenergy recovery at 160 °C. The input energy of the livestock manure, obtained by mixing pig slurry... [more]
The Conversion of Pistachio and Walnut Shell Waste into Valuable Components with Subcritical Water
Maja Čolnik, Mihael Irgolič, Amra Perva, Mojca Škerget
June 21, 2024 (v1)
Subject: Materials
Keywords: conventional extraction, furfurals, pistachio shells, subcritical water extraction, sugars, valuable compounds, walnut shells, waste biomass
Pistachio and walnut shells accumulate in large quantities as waste during food processing and represent a promising lignocellulosic biomass for the extraction of valuable components. Subcritical water technology was used as an environmentally friendly technique to study the extraction of active ingredients and other valuable degradation products from walnut and pistachio waste. Subcritical water extraction (SWE) was carried out under different process conditions (temperature (150−300 °C) and short reaction times (15−60 min)) and compared with conventional extraction using different organic solvents (acetone, 50% acetone and ethanol). The extracts obtained from pistachio and walnut shell waste are rich in various bioactive and valuable components. The highest contents of total phenols (127.08 mg GA/g extract at 300 °C for 15 min, from walnut shells), total flavonoids (10.18 mg QU/g extract at 200 °C for 60 min, from pistachio shells), total carbohydrates (602.14 mg TCH/g extract at 200... [more]
Zeolites Derived from Natural Kaolinite for CO2 Adsorption
Giorgio Celoria, Federico Begni, Geo Paul, Enrico Boccaleri, Valentino Merlo, Leonardo Marchese, Chiara Bisio
June 21, 2024 (v1)
Subject: Materials
Keywords: alkaline fusion, CO2 adsorption, natural kaolinite, Si/Al ratio, zeolite LTA, zeolite X
This manuscript deals with the synthesis of different types of zeolites from natural kaolinite samples for CO2 adsorption. A zeolite A was prepared from kaolinite by means of an alkaline fusion process, followed by hydrothermal treatment, whereas a highly crystalline zeolite X was synthesized by optimizing the previously mentioned synthetic procedure. In detail, the SiO2/Al2O3 molar ratio in the preliminary mixture was modified with the addition of a secondary silicon source (sodium silicate) in order to obtain the one required for zeolites X. The physicochemical properties of the pristine clay and of the different zeolites were investigated by means of a multi-technique approach, including XRPD; SEM-EDX; 23Na, 27Al and 29Si MAS NMR spectroscopy; and N2 physisorption analysis at 77 K. Since the Si and Al molar ratios and reactivities are key parameters for the synthesis of zeolites, these aspects, primarily related to the use of a naturally occurring aluminosilicate as the raw material... [more]
Effect of Dose Rate on Tribological Properties of 8Cr4Mo4V Subjected to Plasma Immersion Ion Implantation
Bin Miao, Junbo Niu, Jiaxu Guo, Zifeng Ding, Xinghong Zhang, Xinxin Ma, Liqin Wang
June 21, 2024 (v1)
Subject: Materials
Keywords: 8Cr4Mo4V steel, dose-rate, nitrogen ion implantation, plasma immersion ion implantation, wear resistance
The lack of service lifetime of bearings has become a bottleneck that restricts the performance of aero engines. How to solve or improve this problem is the focus of most surface engineering researchers at present. In this study, plasma immersion ion implantation was conducted; in order to enhance the ion implantation efficiency and improve the wear resistance of 8Cr4Mo4V bearing steel, the dose-rate-enhanced method was adopted during ion implantation. The surface roughness, phase constituents, elemental concentration, hardness, contact angle and wear resistance of samples after ion implantation was determined by atomic force microscopy (AFM), grazing incidence X-ray diffraction (GIXRD), elemental dispersive spectroscopy (EDS), X-ray diffraction, nanoindentation tester, universal friction and wear tester, etc. The results showed that the high-dose-rate method had a significant enhancement influence on ion implantation efficiency. At the dose rate of 2.60 × 1017 ions/cm2·h, the roughnes... [more]
Effect of Slaked Lime on the Properties of Sodium Sulfate-Activated Alkali-Activated Slag Cement
Juan He, Mengmeng Li, Wenbin Bai, Guochen Sang, Xuefeng Song
June 21, 2024 (v1)
Subject: Materials
Keywords: alkali-activated slag cement, mechanical strength, shrinkage properties, slaked lime, sodium sulfate
Sodium sulfate (SS) is a neutral activator. SS-activated alkali-activated slag cement (AASC) has lower shrinkage. However, it sets slowly, and the mechanical property develops slowly. Slaked lime (SL) is an alkaline substance widely used in industry that can be used as an activator in AASC. In this paper, SL was used alone, and SL and SS were mixed together to prepare AASC. The effects of SL content on the setting time, shrinkage properties and mechanical strength of AASC were investigated. Furthermore, the mechanism was explored with the analysis of microscopic tests. The results showed that SS could not be used as an activator alone, while SL could be used as an activator alone, and SS could be combined with SL to prepare AASC. The setting time of the SL system or the SS-SL mix system decreased with the increase in SL. The mechanical properties of the SL system were poor. The SS-SL system showed the highest mechanical properties when SL was 3%. With the increase in SL, the autogenous... [more]
Variability in Physical Properties of Logging and Sawmill Residues for Making Wood Pellets
Jun Sian Lee, Hamid Rezaei, Omid Gholami Banadkoki, Fahimeh Yazdan Panah, Shahab Sokhansanj
June 21, 2024 (v1)
Subject: Materials
Keywords: ash, Biomass, density, moisture, particle sizes, pellets
Wood pellets are a versatile ingredient to produce bioenergy and bioproducts. Wood pellet manufacturing in Canada started as a way of using the excess sawdust from sawmilling operations. With the recent dwindling availability of sawdust and the growth in demand for wood pellets, the industry uses more non-sawdust woody biomass as feedstock. In this study, woody biomass materials received from nine wood pellet plants in British Columbia (BC) and Alberta were analyzed for their properties, especially those used for fractionating feedstock to make pellets. Half of the feedstock received at the plants was non-sawdust. Moisture contents varied from 10 to 60% wet basis, with the hog having an average of 50%. Ash contents ranged from 0.3 to 4% dry basis and were highest in the hog fraction. Bulk density varied from 50 to 450 kg/m3, with shavings having the lowest bulk density. Particle density ranged from 359 kg/m3 for infeed mix to 513 kg/m3 for sawdust. In total, 25% of particles received w... [more]
Biosensing Applications of Molecularly Imprinted-Polymer-Based Nanomaterials
Yeşeren Saylan, Seçkin Kılıç, Adil Denizli
June 21, 2024 (v1)
Subject: Materials
Keywords: molecular imprinting, molecularly imprinted polymers, nanofilm, nanogel, nanomaterial, nanoparticle, sensor applications
In the realm of sensing technologies, the appeal of sensors lies in their exceptional detection ability, high selectivity, sensitivity, cost-effectiveness, and minimal sample usage. Notably, molecularly imprinted polymer (MIP)-based sensors have emerged as focal points of interest spanning from clinical to environmental applications. These sensors offer a promising avenue for rapid, selective, reusable, and real-time screening of diverse molecules. The preparation technologies employed in crafting various polymer formats, ranging from microparticles to nanomaterials, wield a profound influence. These techniques significantly impact the assembly of simplified sensing systems, showcasing remarkable compatibility with other technologies. Moreover, they are poised to play a pivotal role in the realization of next-generation platforms, streamlining the fabrication of sensing systems tailored for diverse objectives. This review serves as a comprehensive exploration, offering concise insights... [more]
An Electrolyte-Free Thermo-Rechargeable Battery Made of Prussian Blue Analog Thin Films
Takayuki Shibata, Hirotada Matsushima, Ichiro Nagai, Hitoshi Ohnuki
June 21, 2024 (v1)
Subject: Materials
Keywords: energy harvesting, Prussian blue analogs, tertiary battery, thermo-rechargeable battery
Thermo-rechargeable batteries, or tertiary batteries, are prospective energy-harvesting devices that are charged by changes in the battery temperature. Previous studies on tertiary batteries have utilized an electrolyte solution, yet the volume of this electrolyte solution could be a disadvantage in terms of the heat capacity given to the tertiary batteries. To overcome this drawback, the performance of an electrolyte-free tertiary battery consisting of physically joined Na1.60Co[Fe(CN)6]0.902.9H2O (NCF90) and Na0.72Ni[Fe(CN)6]0.685.1H2O (NNF68) thin films was investigated for the first time. During thermal cycling between 5 °C and 15 °C, the thermal voltage (VTB) was observed to be 8.4 mV. This result is comparable to the VTB of conventional tertiary batteries that use electrolyte solutions made of NCF90 and NNF68 thin films.
Thermophysical and Electrical Properties of Ethylene Glycol-Based Nanofluids Containing CaCO3
Julian Traciak, David Cabaleiro, Javier P. Vallejo, Jacek Fal
June 21, 2024 (v1)
Subject: Materials
Keywords: CaCO3, density, electrical properties, nanofluids, surface tension, thermal conductivity, viscosity
The thermophysical properties of various types of nanofluids are often studied to find more effective working fluids for heat transfer applications. In this paper, the mass density, isobaric heat capacity, thermal conductivity, dynamic viscosity surface tension, and electrical properties of calcium carbonate-ethylene glycol (CaCO3-EG) nanofluids were investigated. The samples with mass fractions of 0.01, 0.02, and 0.03 were prepared with a two-step method and studied as well as pure base fluid (ethylene glycol). The measurements were conducted at temperatures between 283.15 and 313.15 K and the obtained results show the impact of CaCO3 nanoparticles on the thermophysical and electrical properties of ethylene glycol.
Generation of Hydrogen Peroxide and Phenolic Content in Plant-Material-Based Beverages and Spices
Kacper Kut, Anna Tama, Paulina Furdak, Grzegorz Bartosz, Izabela Sadowska-Bartosz
June 21, 2024 (v1)
Subject: Materials
Keywords: cacao, coffee, hydrogen peroxide, medicinal herbs, phenolics, spices, tea
Phenolics are the main components of plant extracts contributing to their antioxidant activity. However, they autoxidize, generating hydrogen peroxide. This study aimed to examine the correlation between the phenolic content, total antioxidant capacity (TAC), and the amount of H2O2 generated in extracts of 18 various plant materials. A significant correlation was found between the phenolic content and TAC measured by ABTS● decolorization, CUPRAC, FRAP, and DPPH● decolorization methods (correlation coefficients r of 0.94, 0.93, 0.90, and 0.78, respectively). However, the correlation between the phenolic content and H2O2 amount generated upon brewing (r = 0.25) and after 1 h incubation (r = −0.37) was low or negative. The correlation between the phenolic content and the change of H2O2 concentration during 1 h incubation of the extracts was negative (r = −0.61). Examination of three phenolics (pyrogallol, gallic acid, and quercetin) showed that all compounds generate but also scavenge H2O... [more]
Effects of Superabsorbent Polymer Addition on the Thermal Properties of Eutectic Phase Change Material
Seok-Joon Lee, Seul-Hyun Park
June 21, 2024 (v1)
Subject: Materials
Keywords: nucleating agent, phase change material, refrigerator, super absorbent polymer, supercooling, thermal properties, thickener
In this study, the influence of a super absorbent polymer (SAP) addition on the thermal properties of phase change material (PCM) was investigated. It was found that adding SAP reduced the melting temperature of PCM and improved phase separation properties. While the addition of 1.0 wt% of SAP to PCMs decreased latent heat by 3 J/g to 24.4 J/g, the addition was determined to be necessary to prevent leaks from a functional duct unit (FDU) and assure product stability. The results obtained from a series of brine refrigeration tests indicate that the supercooling temperature decreased by 0.3 °C to 1.7 °C when 1.0 wt% of SAP was added to PCM. The addition of SAP to PCM appears to promote supercooling by encouraging condensation during phase change. As a result of applying SAP-added PCM to the FDU, the isothermal operation performance was improved compared to existing refrigerators.
Microbiome Structure of Activated Sludge after Adaptation to Landfill Leachate Treatment in a Lab-Scale Sequencing Batch Reactor
Mihaela Kirilova, Ivaylo Yotinov, Yovana Todorova, Nora Dinova, Stilyana Lincheva, Irina Schneider, Yana Topalova
June 21, 2024 (v1)
Subject: Materials
Keywords: activated sludge adaptation, catechol dioxygenases, landfill leachate, Pseudomonas, sludge disintegration
During adaptation to waters that are rich in xenobiotics, biological systems pass through multiple stages. The first one is related to the restructuring of communities, pronounced destruction of the structure, and multiplication of active biodegradants. The purpose of the present research was to describe the microbiome restructuring that occurs during the adaptation stage in landfill leachate treatment. In a model SBR (sequencing batch reactor), a 21-day purification process of landfill leachate was simulated. Wastewater was fed in increasing concentrations. When undiluted leachate entered, the activated sludge structure disintegrated (Sludge Volume Index—4.6 mL/g). The Chemical Oxygen Demand and ammonium nitrogen concentration remained at high values in the influent (2321.11 mgO2/L and 573.20 mg/L, respectively). A significant amount of free-swimming cells was found, and the number of aerobic heterotrophs and bacteria of the genera Pseudomonas and Acinetobacter increased by up to 125... [more]
Effect of the Curvature Radius on Single-Droplet Dynamic Characteristics within a Concave-Wall Jet
Bin Gong, Aibo Jian, Jing Zhang, Guang Yang, Yifeng Liu
June 21, 2024 (v1)
Subject: Materials
Keywords: concave-wall jet, deformation mechanism, droplet, heterogeneous, interfacial energy
The centrifugal force field in a hydrocyclone was affected by the concave-wall curvature radius R0, and the mechanism underlying droplet deformation was closely related to the mass transfer efficiency. Numerical simulation and experimental data were collected to reveal the deformation characteristics and mechanism of a single droplet crossing concave-wall jet. Normalized interfacial energy γ and stretching performance were provided to investigate the droplet deformation process. The results showed that the droplet was stretched along the streamwise direction and shrank along the spanwise direction in the concave-wall jet. The droplet interfacial energy and deformation were the largest when the droplet crossed the jet boundary at t = 0.20 s. The maximum γ value increased with the increase in R0 by 57.3% to 71.4%, and the distance between the droplet and concave wall increased with R0. The Q-criterion was exported to show the increase in the vortex strength with the decrease in R0 at the... [more]
Advancing Methodologies for Elemental Transfer Quantification in The Submerged Arc Welding Process: A Case Study of CaO-SiO2-MnO Flux
Jun Fan, Jin Zhang, Dan Zhang
June 21, 2024 (v1)
Subject: Materials
Keywords: elemental transfer quantification, silicon-manganese flux, welding metallurgy, welding process
In submerged arc welding, evaluating elemental transfer behaviors is critical for selecting and designing welding materials. Accurate assessment of O, Si, and Mn transfer behavior is essential for ensuring process quality, particularly when silicon-manganese fluxes are applied. Traditional quantification methods, however, focus only on chemical reactions in the weld pool zone, potentially overlooking the cross-zone elemental transfer behavior and leading to significant predictive inaccuracies. This study investigates the CaO-SiO2-MnO flux, a prevalent silicon-manganese flux, focusing on O, Si, and Mn, which exhibit notable transfer behaviors of O, Si, and Mn. By employing a multi-zone approach and integrating various scientific principles, the research aims to improve the accuracy of predicting elemental transfer behaviors and deepen the understanding of the metallurgical processes in submerged arc welding when silicon-manganese fluxes are employed. The study proposes strategic enhance... [more]
Use of Lactulose as Prebiotic and Chitosan Coating for Improvement the Viability of Lactobacillus sp. FM4.C1.2 Microencapsulate with Alginate
Fabiola Rizo-Vázquez, Alfredo Vázquez-Ovando, David Mejía-Reyes, Didiana Gálvez-López, Raymundo Rosas-Quijano
June 21, 2024 (v1)
Subject: Materials
Keywords: emulsion, encapsulation efficiency, extrusion, sodium alginate, viability
Lactic acid bacteria (LAB) constitute the microbial group most used as probiotics; however, many strains reduce their viability during their transit through the body. The objective of this study was to evaluate the effect of two microencapsulation techniques, as well as the incorporation of lactulose as a prebiotic and the use of chitosan coating on the microcapsules, on the viability of the Lactobacillus sp. strain FM4.C1.2. LAB were microencapsulated by extrusion or emulsion, using 2% sodium alginate as encapsulating matrix and lactulose (2 or 4%) as the prebiotic. The encapsulation efficiency was evaluated, and the capsules were measured for moisture and size. The encapsulation efficiency ranged between 80.64 and 99.32% for both techniques, with capsule sizes between 140.64 and 1465.65 µm and moisture contents from 88.23 to 98.04%. The microcapsules of some selected treatments (five) were later coated with chitosan and LAB survival was evaluated both in coated and uncoated microcaps... [more]
Showing records 1 to 25 of 4403. [First] Page: 1 2 3 4 5 Last
[Show All Subjects]