Browse
Subjects
Records with Subject: Materials
Showing records 3720 to 3744 of 4494. [First] Page: 1 146 147 148 149 150 151 152 153 154 Last
Relationship between Some Colloidal Properties of Non-Ionic-Anionic Surfactant Mixtures
Roland Nagy, Réka Kothencz, Máté Hartyányi, László Bartha
February 21, 2023 (v1)
Subject: Materials
Keywords: emulsification capacity, HLB value, interfacial tension, particle size, surfactants
Non-ionic surfactants are compatible with different types of materials, therefore they can be applied in various packages. Fatty-acid derivates as non-ionic surfactants and their mixtures were investigated to study their colloidal behavior. The HLB value, the particle size, the emulsification capacity and the interfacial tension of various commercial, non-ionic surfactants, and their mixtures with sodium lauryl-ether-sulfate (SLES), were determined. The surfactant mixtures were prepared in different non-ionic: anionic surfactant ratios to examine their effect on several surfactant characteristics. The interfacial tension between the oil phase and aqueous phase was measured using the spinning drop method and the average hydrodynamic diameter of surfactants in the aqueous solution was determined using the dynamic light scattering method. The relationship between various colloidal properties of surfactants was investigated. It was found that there is a significant relationship between the... [more]
Special Issue “Micro and Nanotechnology: Application in Surface Modification”
Kosmas Ellinas, Panagiotis Dimitrakellis
February 21, 2023 (v1)
Subject: Materials
Surface modification is crucial to the fabrication of (multi)functional materials and interfaces for a range of applications, such as superhydrophobic and self-cleaning surfaces, anti-biofouling and antibacterial coatings, dropwise condensation, packaging materials, sensors, catalysis, and photonics [...]
Molybdenum Modified Sol−Gel Synthesized TiO2 for the Photocatalytic Degradation of Carbamazepine under UV Irradiation
Chukwuka Bethel Anucha, Emin Bacaksiz, Vassilis N. Stathopoulos, Pavlos K. Pandis, Christos Argirusis, Constantina-Dia Andreouli, Zoi Tatoudi, Ilknur Altin
February 21, 2023 (v1)
Subject: Materials
Keywords: AOPs, carbamazepine, CECs, doping, heterogeneous photocatalysis, semiconductors, sol–gel, sonochemical doping, TiO2, UV-visible
Pharmaceutical CEC compounds are a potential threat to man, animals, and the environment. In this study, a sol−gel-derived TiO2 (SynTiO2) was produced and subsequently sonochemically doped with a 1.5 wt% Mo to obtain the final product (Mo (1.5 wt%)/SynTiO2). The as-prepared materials were characterized for phase structure, surface, and optical properties by XRD, TEM, N2 adsorption−desorption BET isotherm at 77 K, and PSD by BJH applications, FTIR, XPS, and UV-Vis measurements in DRS mode. Estimated average crystallite size, particle size, surface area, pore-volume, pore size, and energy bandgap were 16.10 nm, 24.55 nm, 43.30 m2/g, 0.07 cm3/g, 6.23 nm, and 3.05 eV, respectively, for Mo/SynTiO2. The same structural parameters were also estimated for the unmodified SynTiO2 with respective values of 14.24 nm, 16.02 nm, 133.87 m2/g, 0.08 cm3/g, 2.32 nm, and 3.3 eV. Structurally improved (Mo (1.5 wt%)/SynTiO2) achieved ≈100% carbamazepine (CBZ) degradation after 240 min UV irradiation under... [more]
Preparation of a Mulberry-like MnO Specimen and Its Lithium Property
Yuan-Xiang Fu, Hong-Shen Huang, Wu-Jie Ge, Wei Qiu, Xian-Yinan Pei
February 21, 2023 (v1)
Subject: Materials
Keywords: anode material, lithium property, mulberry-like MnO
A mulberry-like MnO specimen was prepared using a MnCO3 sample under nitrogen (N2) protection at 700 °C (denoted as MnO-700). When the specimen was used in lithium-ion batteries (LIBs) as anode material, the reversible capacity of 702 mAh g−1 was displayed after 120 cycles at a current density 200 mA g−1, and 365 mAh g−1 of discharge capacity was obtained at 1000 mA g−1 at the 200th cycle. Meanwhile, the sample also exhibited an excellent rate capacity (224 mAh g−1 at 2000 mA g−1). The MnO-700 sample displayed a favorable electrochemical performance that may be ascribed to the unique mulberry-like structure of the MnO microparticles, which can provide enough space to satisfy the volume change of the MnO microparticles during lithium cycling, and also lead to more transfer paths for Li+ insertion/extraction during charge/discharge processes.
Extraction of Polyphenols from Unripened Coffee (Coffea Arabica) Residues and Use as a Natural Coagulant for Removing Turbidity
Diana Marcela Cuesta-Parra, Felipe Correa-Mahecha, Juan Pablo Rodríguez-Miranda, Octavio José Salcedo-Parra, Edwin Rivas-Trujillo
February 21, 2023 (v1)
Subject: Materials
Keywords: Coffea arabica, natural coagulant, turbidity, ultrasound assisted extraction
The coffee agribusiness generates significant amounts of waste that becomes an environmental problem in producing countries. For example, synthetic coagulants have sustainability disadvantages. Immature coffee beans are collected together with mature beans, and their high polyphenol content makes them unsuitable for coffee production and commercialization. This paper aims to test the coagulant activity of polyphenols extracted from Coffea arabica residues in synthetic water samples to use them as raw material for producing a natural coagulant based on bioeconomy. It would thus allow immature coffee beans to recover, avoiding their inadequate disposition. An extract was obtained from residual green coffee beans using the ultrasound-assisted separation technique with a mixture of ethanol and water in a 1:1 ratio. The Folin−Ciocalteu method was applied for the total polyphenols quantification, resulting in a concentration of 73.54 ± 0.05 mg GAE (Gallic Acid Equivalent) per gram on a dry c... [more]
Effect of Cooling Rate on the Grain Morphology and Element Segregation Behavior of Fe-Mn-Al-C Low-Density Steel during Solidification
Shihui Huang, Guangqiang Li, Zhan Zhang, Qingbiao Tan, Guoliang Zhu
February 21, 2023 (v1)
Subject: Materials
Keywords: cooling rate, elemental segregation, Fe-Mn-Al-C steel, microstructure
Mold with diameter sizes of 140 mm, 80 mm, 40 mm and 15 mm were designed to obtain the ingot of Fe-30Mn-10Al-1.1C low-density steel under different cooling rates. The influence of cooling rate on the grain morphology and elemental segregation behavior during the steel solidification process was analyzed by methods including inductively coupled plasma, scanning electron microscope and energy dispersive spectroscopy. The solidification sequence of the low-density steel was calculated by JMatPro 7.0 thermodynamic software. The results show that the microstructure of the steel is mainly austenite and contains a small amount of ferrite. The solidification order in the steel is: L → α, L → γ and α → γ, L → γ + MC. As the cooling rate increases from 1.69 °C/s to 10.28 °C/s, the ferrite phase precipitation increases by 16.7%, and the grain size decreases significantly, and in particular, the austenitic grain size decreases by 26%. With the increase in cooling rate, the microscopic segregation... [more]
Quantitative Method for Liquid Chromatography−Mass Spectrometry Based on Multi-Sliding Window and Noise Estimation
Mingzheng Jia, Meng Wu, Yanjie Li, Baolin Xiong, Lei Wang, Xing Ling, Wenbo Cheng, Wen-Fei Dong
February 21, 2023 (v1)
Subject: Materials
Keywords: LC-MS/MS, multi-window-based signal-to-noise ratio estimation algorithm, peak detection, quantitative
LC-MS/MS uses information on the mass peaks and peak areas of samples to conduct quantitative analysis. However, in the detection of clinical samples, the spectrograms of the compounds are interfered with for different reasons, which makes the identification of chromatographic peaks more difficult. Therefore, to improve the chromatographic interference problem, this paper first proposes a multi-window-based signal-to-noise ratio estimation algorithm, which contains the steps of raw data denoising, peak identification, peak area calculation and curve fitting to obtain accurate quantitative analysis results of the samples. Through the chromatographic peak identification of an extracted ion chromatogram of VD2 in an 80 ng/mL standard and the spectral peak identification of data from an open-source database, the identification results show that the algorithm has a better peak detection performance. The accuracy of the quantitative analysis was verified using the LC-HTQ-2020 triple quadrupo... [more]
Drug Carriers: A Review on the Most Used Mathematical Models for Drug Release
Paolo Trucillo
February 21, 2023 (v1)
Subject: Materials
Keywords: drug carriers, drug release, drug-polymer interactions, mathematical models
Carriers are protective transporters of drugs to target cells, facilitating therapy under each points of view, such as fast healing, reducing infective phenomena, and curing illnesses while avoiding side effects. Over the last 60 years, several scientists have studied drug carrier properties, trying to adapt them to the release environment. Drug/Carrier interaction phenomena have been deeply studied, and the release kinetics have been modeled according to the occurring phenomena involved in the system. It is not easy to define models’ advantages and disadvantages, since each of them may fit in a specific situation, considering material interactions, diffusion and erosion phenomena, and, no less important, the behavior of receiving medium. This work represents a critical review on main mathematical models concerning their dependency on physical, chemical, empirical, or semi-empirical variables. A quantitative representation of release profiles has been shown for the most representative... [more]
Study on Performance Improvement of Sodium Acetate Trihydrate in Thermal Energy Storage System by Disturbance
Suyaola Wang, Chuang Wang, Muhammad Bilal Hussain, Xingxing Cheng, Zhiqiang Wang
February 21, 2023 (v1)
Subject: Materials
Keywords: coefficient of thermal conductivity, degree of supercooling, disturbance, phase separation, sodium acetate trihydrate
Phase change materials (PCM) have been widely used in Thermal Energy Storage (TES) Systems. Considering the energy efficiency and the use of domestic hot water, the melting temperature range of phase change materials is considered to be optimal in the range of 50−60 °C. The most commonly used is sodium acetate trihydrate-based phase change material, which has the advantages of high latent heat and low price, but its high supercooling, low thermal conductivity, and phase separation affect its application. Therefore, this paper used sodium acetate trihydrate, disodium hydrogen phosphate dodecahydrate (DSP), and expanded graphite (EG) as raw materials to prepare composite phase change materials (CPCM) and used physical disturbance to further improve their properties. Firstly, their thermophysical properties were investigated by the step cooling curve method, differential scanning calorimetry (DSC), and x-ray diffraction (XRD). Secondly, in order to further evaluate the effect of physical... [more]
Microstructure Evolution of Inertia Friction Welded Joints of TC21 Titanium Alloy
Hongying Wang, Zihao Li, Shengsheng Zhao, Zhijun Li, Weijie Tang, Fayu Wu, Jun Zhou
February 21, 2023 (v1)
Subject: Materials
Keywords: inertia friction welding, microstructure, phase composition, TC21 titanium alloy
In this paper, TC21 titanium alloy welded joints were successfully formed through inertial friction welding (IFW) processes. Microstructure evolution of IFW joints was investigated by way of different analysis methods including optical microscope (OM), scanning electron microscope(SEM), Electron Back-Scattered Diffraction(EBSD), X-Ray Diffraction(XRD), and Energy Dispersive Spectrometer(EDS). The results indicate that large-sized equiaxial β grains, original α phases, and basketweave structure existing in the BM have completely disappeared in the WZ. Instead, fine equiaxial grains sized at 20−30 μm and very fine α + β lamellar microstructure are formed in the WZ. However, as transition zones, the microstructures of the TMAZ and HAZ are also in transition state while the microstructures existing in the BM partially remain in the TMAZ and completely remain in the HAZ. In addition, second α phases are precipitated and fine α + β lamellar microstructure are formed on the original β base in... [more]
Antibacterial and Antifungal Activity of Functionalized Cotton Fabric with Nanocomposite Based on Silver Nanoparticles and Carboxymethyl Chitosan
Carlos Alberto Arenas-Chávez, Luciana Maria de Hollanda, Arturo A. Arce-Esquivel, Aldo Alvarez-Risco, Shyla Del-Aguila-Arcentales, Jaime A. Yáñez, Corina Vera-Gonzales
February 21, 2023 (v1)
Subject: Materials
Keywords: antifungal, antimicrobial, cotton, functionalized fabric, nanocomposite
Cotton is the most widely used natural fiber for textiles; however, the capacity of cotton fibers to absorb large amounts of moisture, retain oxygen, and have a high specific surface area makes them 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 continue the assessment of our developed nanocomposite and evaluate the antibacterial and antifungal activity of the nanocomposite based on silver nanoparticles and carboxymethyl chitosan (AgNPs-CMC) against Escherichia coli, Staphylococcus aureus, and Candida albicans, evaluated by the well diffusion method. The antibacterial activity against E. coli and S. aureus was also evaluated by the qualitative method of inhibition zone and the quantitative method of co... [more]
Analysis of Sealing Performance of Metal B-ring Self-Tightening Structure
Bingjun Gao, Han Gao, Junhua Dong, Yongming An, Chuanzhi Wang
February 21, 2023 (v1)
Subject: Materials
Keywords: B-ring, FEM, leakage, self-tightening seal
Process industries often use B-ring self-tightening sealing structures and rely on interference assembly to meet the initial sealing requirements. Therefore, determining reasonable B-ring material, size and interference is crucial to ensure the sealing performance of the structure. In this paper, based on elastic deformation analysis, the deformation co-ordination equation of a B-ring sealing structure was established, and a sealing contact pressure calculation formula was obtained, with discussion of the main factors affecting sealing performance. With the finite element method, transient temperature field analysis was carried out for startup and shutdown load cases, and contact analysis was carried out for interference assembly, startup and shutdown. Based on the evaluation criteria of sealing performance with proposed sealing rate and leakage parameters, the effects of material properties, interference, B-ring size, etc., on sealing performance were investigated, revealing that alth... [more]
Efficient Removal of Dyes from Aqueous Solution by Adsorption on L-Arginine-Modified Mesoporous Silica Nanoparticles
Abdullah M. Alswieleh
February 21, 2023 (v1)
Subject: Materials
Keywords: dye removal, mesoporous silica, surface modification
The use of mesoporous silica modified with L-arginine (Ar-MSNPs) for the removal of ionic dyes from aqueous solutions has been investigated. Several analytical techniques have been used to determine the characteristics of nanoadsorbents. The removal of crystal violet and fluorescein was performed using the batch method to investigate the effects of cultivation pH, initial concentrations of dyes, and exposure time on adsorption efficiency. The optimum adsorption of fluorescein was achieved at pH 2, whereas the optimum adsorption of crystal violet was achieved at pH 13. The equilibrium was established in both systems at 20 min at low concentrations, and approximately 30 min at high concentrations. The equilibrium adsorption data was analyzed using Langmuir and Freundlich isotherm models. The correlation coefficient (R2) values of the isotherms presented the best fit with the Langmuir isotherm. The adsorption kinetic data was fitted with the pseudo second-order model for both systems.
Selective Ion Removal by Capacitive Deionization (CDI)-Based Technologies
Shuqian Chai, Jiarui Xi, Ling Chen, Wei He, Junjie Shen, Hui Gong
February 21, 2023 (v1)
Subject: Materials
Keywords: capacitive deionization, desalination, electrode materials, heavy metal, nutrients, selective ion removal, water softening
Severe freshwater shortages and global pollution make selective removal of target ions from solutions of great significance for water purification and resource recovery. Capacitive deionization (CDI) removes charged ions and molecules from water by applying a low applied electric field across the electrodes and has received much attention due to its lower energy consumption and sustainability. Its application field has been expanding in the past few years. In this paper, we report an overview of the current status of selective ion removal in CDI. This paper also discusses the prospects of selective CDI, including desalination, water softening, heavy metal removal and recovery, nutrient removal, and other common ion removal techniques. The insights from this review will inform the implementation of CDI technology.
Modification of Quaternary Clays Using Recycled Fines from Construction and Demolition Waste
Roumiana Zaharieva, Daniel Evlogiev, Nikolay Kerenchev, Tsveta Stanimirova
February 21, 2023 (v1)
Subject: Materials
Keywords: CDW, clay, recycled concrete powder, recycled gypsum, shear resistance, soil compaction, soil deformation, the oedometer modulus, UCS
Foundation of buildings in soft soil such as quaternary clay is often associated with difficult compaction, settlement, non-uniform and/or excessive deformation, and unsatisfactory shear resistance. The present study aims to assess the possibility of using recycled fines from construction and demolition waste, such as mechanically treated gypsum and waste concrete powder (WCP), instead of ordinary binders or industrial waste, in the stabilization of quaternary clay. A detailed characterization of soil components is presented. Seven mixes with various proportions of gypsum and WCP are prepared. Main geotechnical parameters of the modified soil are studied by applying standardized methods with a few deviations. XRD analysis and pH measurements are performed. It was found that the effect of 5% to 20% recycled di-hydrate gypsum is limited to improvement in moist soil compatibility. A gypsum content of 10% positively impacts soil cohesion and the oedometer modulus. WCP is an active componen... [more]
A Novel Bone Gelatin Prepared by Enzymatic Catalysis with High Crosslinking Activity of MTGase for Gelatinization Properties of Minced Pork
Qiaoqiao Han, Juncai Leng, Tiantian Dong, Yanli Ma, Wei Zhao
February 21, 2023 (v1)
Subject: Materials
Keywords: bone gelatin, crosslink, microbial transglutaminase, minced pork, thermo-reversibility
A novel gelatin prepared by enzymatic catalysis (type-E bone gelatin) was developed in our group. In this study, the high crosslinking activity of type-E bone gelatin with microbial transglutaminase (MTGase) was found and further used for the gelatinization properties of minced pork. The results showed that the contents of lysine and glutamine in type-E bone gelatin were higher than that of traditional gelatin prepared by acid (type-A gelatin) and alkali (type-B gelatin) methods, which are as action sites for MTGase. The crosslinking degree (79%) of type-E was approximately 4.9 times that of type-A and 5.6 times that of type-B at 1.44 U/g MTGase. Moreover, the type-E gel showed thermal irreversibility when the MTGase concentration was higher than 0.90 U/g due to high crosslinking activity. For minced pork gel, the water-holding capacity and texture properties of minced pork modified with type-E bone gelatin crosslinked by MTGase were improved and cooking loss was significantly reduced.
Development of a Novel Green Bio-Nanofluid from Sapindus Saponaria for Enhanced Oil Recovery Processes
Lady J. Giraldo, Dahiana Galeano-Caro, Carlos A. Franco, Jesús Archila, Fabio Villamil, Farid B. Cortés, Camilo A. Franco
February 21, 2023 (v1)
Subject: Materials
Keywords: bio-nanofluid, EOR, IFT, nanoparticles, saponins
The main objective of this study is to develop a novel green-nanofluid from Sapindus Saponaria for its application in enhanced oil recovery (EOR) processes. The bio-nanofluid is composed of a green active compound (AGC), bio-ethanol, and commercial surfactant (SB) at a low concentration. The AGC was obtained from soapberry “Sapindus Saponaria” using the alcoholic extraction method and characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and critical micellar concentration (CMC) to verify the content of saponins as active agents with surface-active behavior. Three types of silica-based nanoparticles were used and characterized by FTIR, TGA, and dynamic light scattering (DLS) analysis. Two commercial nanoparticles (SiO2-C1 and SiO2-C2) were evaluated, and a third one (SiO2-RH) was synthesized from rice husks as an ecological nanomaterial alternative. The performance of the adjusted systems was evaluated by capillary number (effective interfac... [more]
Lightweight Design and Experimental Study of Ceramic Composite Armor
Jianmei Chen, Yihui Zeng, Xiaopeng Liang, Yanbin Hou, Yunliang Wang, Zhenqi Sun, Shuwan Cui
February 21, 2023 (v1)
Subject: Materials
Keywords: bulletproof performance, ceramic, composite armor, fiber composite material, lightweight, oblique penetration
Ceramic/fiber composite armor is a hot research topic of bulletproof equipment. The lightweight design of ceramic materials and structures has attracted much attention. In this work, in the light of the remarkable performance of ceramic against elastic and oblique penetration, a novel honeycomb ceramic panel with a hexagonal prism and spherical body was designed. The splicing ceramic/fiber composite plate was bonded with a PE plate. The splicing ceramic/fiber composite was prepared, and the target test of the composite was conducted. The results show that the bulletproof performance of the hexagonal prism spherical crown ceramic/fiber composite plate is better than that of the conventional ceramic/fiber composite plate of the same thickness. The honeycomb spherical crown structure of the ceramic surface can convert the nominal forward penetration into the actual oblique penetration. This surface structure provides an effective lightweight design of ceramic/fiber composite armor.
Hydrothermal Pretreatment of Wheat Straw—Evaluating the Effect of Substrate Disintegration on the Digestibility in Anaerobic Digestion
Timo Zerback, Britt Schumacher, Sören Weinrich, Benedikt Hülsemann, Michael Nelles
February 21, 2023 (v1)
Subject: Materials
Keywords: anaerobic digestion, batch test, biomethane potential, hydrothermal pretreatment, wheat straw
The increasing demand for renewable energy sources and demand-oriented electricity provision makes anaerobic digestion (AD) one of the most promising technologies. In addition to energy crops, the use of lignocellulosic residual and waste materials from agriculture is becoming increasingly important. However, AD of such feedstocks is often associated with difficulties due to the high content of lignocellulose and its microbial persistence. In the present work, the effect of hydrothermal pretreatment (HTP) on the digestibility of wheat straw is investigated and evaluated. Under different HTP temperatures (160−180 °C) and retention times (15−45 min), a significant increase in biomethane potential (BMP) can be observed in all cases. The highest BMP (309.64 mL CH4 g−1 volatile solid (VS) is achieved after pretreatment at 160 °C for 45 min, which corresponds to an increase of 19% of untreated wheat straw. The results of a multiple linear regression model show that the solubilization of orga... [more]
Development and Application of the New Integrated Equipment and Process of the Nine-Steam-Nine-Bask Method in the Processing of Polygonatum cyrtonema
Jun Liu, Zhentao Zhang, Xiulan Huai, Yongxing Wei, Jizhou Zhu, Xiaoqiong Li, Peng Xu, Oluwatosin Ademola Ijabadeniyi
February 21, 2023 (v1)
Subject: Materials
Keywords: integrated equipment, Nine-Steam-Nine-Bask, Polygonatum cyrtonema, polysaccharide, processing
As a traditional processing method, the Nine-Steam-Nine-Bask method has been widely used in the special processing of Chinese medicinal materials. With the highly integrated design and innovation of infiltrating equipment, steaming equipment, drying equipment, and other equipment, a new type of integrated equipment for the Nine-Steam-Nine-Bask method was finally developed and successfully applied in Polygonatum cyrtonema processing. Moreover, seven new processes were explored. The longer the steaming time was, the more steaming and drying cycles, the lower the product recovery rate and the higher the energy consumption. The higher the steaming pressure was, the lower the product recovery rate, the higher the energy consumption and the shorter the drying time. The longer the drying time was, the lower the product recovery rate and polysaccharide content, and the higher the energy consumption. The best new process was XGY1, which had the highest overall score. The steaming process was th... [more]
Development to Emergency Evacuation Decision Making in Hazardous Materials Incidents Using Machine Learning
Chuntak Phark, Shineui Kim, Seungho Jung
February 21, 2023 (v1)
Subject: Materials
Keywords: chemical accident, CNN, evacuation order, HSEES, Machine Learning
Chemical accidents are the biggest factor that hinders the development of the chemical industry. Issuing an emergency evacuation order is one of effective ways to reduce human casualties that may occur due to chemical accidents. The present study proposes a machine learning-based decision making model for faster and more accurate decision making for the issuance of an emergency evacuation order in the event of a chemical accident. To implement the decision making model, supervised learning by the 1-Dimension Convolutional Neural Network based model was carried out using the HSEES and NTSIP data of ATSDR in the United States. An action—victim matrix was devised to determine the validity of emergency evacuation orders and the decision making model was made to learn the matrix so that the decision making model could recommend whether to execute the emergency evacuation orders or not. To make the decision making model learn the chemical accident situations, the embedding technique used in... [more]
Preparation of a Novel Solid Phase Microextraction Fiber for Headspace GC-MS Analysis of Hazardous Odorants in Landfill Leachate
Zonghao Yu, Ruipeng Yu, Shengfang Wu, Weijie Yu, Qijun Song
February 21, 2023 (v1)
Subject: Materials
Keywords: gas chromatography-mass spectrometry, hazardous odorants, one-pot synthesis, solid phase microextraction
The practice of odorant analysis can often be very challenging because odorants are usually composed of a host of volatile organic compounds (VOCs) at low concentrations. Preconcentration with solid phase microextraction (SPME) is a conventional technique for the enrichment of these volatile compounds before analysis by headspace gas chromatography-mass spectrometry (GC-MS). However, commercially available SPME products usually bear the defects of weak mechanical strength and high cost. In this work, novel SPME fibers were prepared by a one-pot synthesis procedure from divinylbenzene (DVB), porous carbon powder (Carbon) and polydimethylsiloxane (PDMS). Factors that influence the extraction efficiency, such as extraction temperature, extraction time, salting effects, pH, stirring rate, desorption temperature and time, were optimized. VOCs in landfills pose a great threat to human health and the environment. The new SPME fibers were successfully applied in the analysis of VOCs from the l... [more]
Novel Magnetically-Recoverable Solid Acid Catalysts with a Hydrophobic Layer in Protecting the Active Sites from Water Poisoning
Jingjing Liu, Juanli Shi, Bo Zhang, Zhenmin Cheng
February 21, 2023 (v1)
Subject: Materials
Keywords: core-shell structured Fe3O4@SiO2 support, esterification reaction, hydrophobicity, magnetically-recoverable solid acid catalysts
Three novel magnetically-recoverable solid acid catalysts (hydrophobic catalysts Fe3O4@SiO2-Me&PrSO3H, Fe3O4@SiO2-Oc&PrSO3H and hydrophilic catalyst Fe3O4@SiO2-PrSO3H) were synthesized by introducing organic propylsulfonic acid and alkyl groups to Fe3O4@SiO2 nanocomposites. We characterized these catalysts by FT-IR, EDS, XRD, VSM and SEM, and found that they had excellent core-shell structure and magnetic responsiveness. We also explored the impact of surface hydrophobicity on activity and stability of catalysts in ethyl acetate (EAC) synthesis reaction. The results indicated that: for reactivity and reusability, Fe3O4@SiO2-Oc&PrSO3H > Fe3O4@SiO2-Me&PrSO3H > Fe3O4@SiO2-PrSO3H. This was because octyl and methyl groups could build a hydrophobic layer on the surfaces of Fe3O4@SiO2-Oc&PrSO3H and Fe3O4@SiO2-Me&PrSO3H, and this could effectively prevent water molecules from poisoning active sites; the hydrophobicity of octyl was stronger than methyl. Fe3O4@SiO2-Oc&PrSO3H also showed higher c... [more]
Purification and Characterization of a Novel Factor of Crotoxin Inter-CRO (V-1), a New Phospholipase A2 Isoform from Crotalus durissus collilineatus Snake Venom Using an In Vitro Neuromuscular Preparation
Corina Vera-Gonzales, Carlos Alberto Arenas-Chávez, Luis A. Ponce-Soto, Aldo Alvarez-Risco, Shyla Del-Aguila-Arcentales, Neal M. Davies, Jaime A. Yáñez
February 21, 2023 (v1)
Subject: Materials
Keywords: Crotalus durissus collilineatus, Crotalus durissus terrificus, HPLC-RP, neurotoxin, V-1
The fractionation of Crotalus durissus collilineatus whole venom through an HPLC chromatographic method enabled the purification of a new V-1 neurotoxin. Inter-CRO (V-1) presents similarity in its primary structure to crotoxin B (CB), suggesting another isoform of this toxin. The aim of this study was to compare V-1 to the crotoxin complex (CA/CB) and CB to elucidate aspects related to its functionality. The homogeneity of the purified protein was confirmed with a molecular mass of 1425.45 Da, further verified by mass spectrometry. The sequence of the protein showed high similarity to other viperid snake venom PLA2 proteins. The results of this study report that V-1 is an uncharacterized novel toxin with different biological activities from CB. V-1 maintained catalytic activity but presented neurotoxic activity as observed by the 2.5-fold increase in twitch tension record compared to control values on isolated muscle cells.
Mechanical and Microstructural Properties of Composite Mortars with Lime, Silica Fume and Rice Husk Ash
Ramalingam Malathy, Ragav Shanmugam, Ill-Min Chung, Seung-Hyun Kim, Mayakrishnan Prabakaran
February 21, 2023 (v1)
Subject: Materials
Keywords: EDX, FT-IR, hydraulic lime, microstructure, reactivity, rice husk ash, SEM, silica fume, XRD
A mixture of hydraulic lime and pozzolanic material can be used as a binder in making concrete and mortar for energy-efficient construction purposes. Generally, lime possesses lower strength and higher setting time. By introducing pozzolans in the lime mortar, their cementitious properties could be increased and could compete with the cement mortars. The use of pozzolan-lime binder in mortar reduces the utilisation of cement, and hence reduces the environmental problem originating from cement production. This study mainly deals with the mechanical and microstructural properties of lime and lime composite mortars made up of hydraulic lime, silica fume and rice husk ash. Three composite mortars were made with the following combination such as hydraulic lime-silica fume (LSF), hydraulic lime-rice husk ash (LRA) and hydraulic lime-silica fume-rice husk ash (LSR). Further, their properties were compared with the pure lime mortar. Preliminary investigations were made on the lime reactivity a... [more]
Showing records 3720 to 3744 of 4494. [First] Page: 1 146 147 148 149 150 151 152 153 154 Last
(0.04 seconds)
[Show All Subjects]

[0.05 s]