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Showing records 3395 to 3419 of 4494. [First] Page: 1 133 134 135 136 137 138 139 140 141 Last
Integration of Decay Time Analysis and Radiation Measurement for Quantum-Dot-Based Scintillator’s Characterization
Sujung Min, Kwang-Hoon Ko, Bumkyoung Seo, Changhyun Roh, Sangbum Hong
February 23, 2023 (v1)
Subject: Materials
Keywords: apparatus, decay time, equipment, integration, process
In this study, we demonstrated the process of an integrated apparatus for decay time analysis and gamma radiation measurement with a liquid-scintillator-based cadmium-doped zinc oxide (CZO) nanomaterial. Generally, time-resolved photon counting is an essential analysis method in the field of precision measurement in the quantum domain. Such photon counting equipment requires a pulse laser that can be repeated quickly while having a sharp pulse width of picoseconds or femtoseconds as a light source. Time-correlated single photon counting (TCSPC) equipment, which is currently a commercial product, is inconvenient for recent development research because the scintillator size and shape are limited. Here, neodymium-doped yttrium aluminum garnet (Nd/YAG) laser TCSPC equipment was constructed to analyze the fluorescence characteristics of scintillators having various sizes and shapes. Then, a liquid scintillator added with CZO nanomaterial was prepared and the Nd/YAG laser TCSPC equipment tes... [more]
Recent Advances in Membrane-Based Biogas and Biohydrogen Upgrading
Cenit Soto, Laura Palacio, Raúl Muñoz, Pedro Prádanos, Antonio Hernandez
February 23, 2023 (v1)
Subject: Materials
Keywords: biogas, biohydrogen, biomethane, membrane separation, mixed matrix membranes, thermal rearrangement, upgrading technologies
Biogas and biohydrogen, due to their renewable nature and zero carbon footprint, are considered two of the gaseous biofuels that will replace conventional fossil fuels. Biogas from anaerobic digestion must be purified and converted into high-quality biomethane prior to use as a vehicle fuel or injection into natural gas networks. Likewise, the enrichment of biohydrogen from dark fermentation requires the removal of CO2, which is the main pollutant of this new gaseous biofuel. Currently, the removal of CO2 from both biogas and biohydrogen is carried out by means of physical/chemical technologies, which exhibit high operating costs and corrosion problems. Biological technologies for CO2 removal from biogas, such as photosynthetic enrichment and hydrogenotrophic enrichment, are still in an experimental development phase. In this context, membrane separation has emerged as the only physical/chemical technology with the potential to improve the performance of CO2 separation from both biogas... [more]
Probing Element Transfer Behavior during the Submerged Arc Welding Process for CaF2-SiO2-Na2O-Cr2O3 Agglomerated Fluxes: A Thermodynamic Approach
Jin Zhang, Qiong Xu
February 23, 2023 (v1)
Subject: Materials
Keywords: element transfer, submerged arc welding, welding flux, welding process
Submerged arc welding joins metal by the heating of the electrode, base metal, and flux in the arc plasma, while the weld pool is protected under the granular flux and molten slag. Due to complex chemical reactions occurring between the arc plasma, weld pool, and molten slag (flux), flux essentially affects the weld metal composition, which, in turn, dictates the mechanical properties of the weldment. Therefore, fine-tuning the weld metal composition is essential to ensure a sound weld, and efforts worldwide have been focused on the control mechanism of flux on the weld metal composition. Recently, agglomerated fluxes have been widely applied due to low energy consumption during manufacture. The Cr2O3-bearing agglomerated flux is one of the most commonly used flux types in fields of heavy industrial applications. However, few works concern the element transfer behavior when Cr2O3-bearing agglomerated fluxes are used. Within this framework, typical agglomerated CaF2-SiO2-Na2O-Cr2O3 flux... [more]
Back-Channel Etched In-Ga-Zn-O Thin-Film Transistor Utilizing Selective Wet-Etching of Copper Source and Drain
Rauf Khan, Muhamad Affiq Bin Misran, Michitaka Ohtaki, Jun Tae Song, Tatsumi Ishihara, Reiji Hattori
February 23, 2023 (v1)
Subject: Materials
Keywords: barrier layer, Cu thermal diffusion, DC sputtering, IGZO TFTs, selective etching of Cu
The electrical performance of the back-channel etched Indium−Gallium−Zinc−Oxide (IGZO) thin-film transistors (TFTs) with copper (Cu) source and drain (S/D) which are patterned by a selective etchant was investigated. The Cu S/D were fabricated on a molybdenum (Mo) layer to prevent the Cu diffusion to the active layer (IGZO). We deposited the Cu layer using thermal evaporation and performed the selective wet etching of Cu using a non-acidic special etchant without damaging the IGZO active layer. We fabricated the IGZO TFTs and compared the performance in terms of linear and saturation region mobility, threshold voltage and ON current (ION). The IGZO TFTs with Mo/Cu S/D exhibit good electrical properties, as the linear region mobility is 12.3 cm2/V-s, saturation region mobility is 11 cm2/V-s, threshold voltage is 1.2 V and ION is 3.16 × 10−6 A. We patterned all the layers by a photolithography process. Finally, we introduced a SiO2-ESL layer to protect the device from external influence.... [more]
Microwave Dielectric Properties of β-CaSiO3 Glass−Ceramics Prepared Using Two-Step Heat Treatment
Jin-Seok Baek, Nak-Beom Jo, Eung-Soo Kim
February 23, 2023 (v1)
Subject: Materials
Keywords: glass–ceramics, microwave dielectric properties, rietveld refinement, α-CaSiO3, β-CaSiO3
The microwave dielectric properties of β-CaSiO3 glass−ceramics are compared with those of α-CaSiO3 ceramics. β-CaSiO3 is prepared using glass−ceramics method with two-step heat treatment at 730 °C for 1−7 h and at 900 °C for 3 h, and α-CaSiO3 is prepared using conventional solid-state reaction and sintered at 1460−1500 °C for 3 h. With increasing holding time at 730 °C, the degree of crystallisation and Qf of the β-CaSiO3 glass−ceramics increased. The β-CaSiO3 specimens heat-treated at 730 °C for 3 h and 900 °C for 3 h exhibit the following dielectric properties: K = 6.57, TCF = −36.22 ppm/°C, and Qf = 52,400 GHz (highest) for the entire range of heat treatment conditions. The Qf difference between β-CaSiO3 and α-CaSiO3 could be explained by the bond characteristics using Rietveld refinement. FT-IR analysis shows that the Ca−O bond is the dominant factor for the Qf of CaSiO3 ceramics compared to the Si−O bond. The higher Qf of β-CaSiO3 than that of α-CaSiO3 can be attributed to the hig... [more]
Manual Application versus Autonomous Release of Water Repellent Agent to Prevent Reinforcement Corrosion in Cracked Concrete
Kim Van Tittelboom, Bjorn Van Belleghem, Philip Van den Heede, Jolien Van Der Putten, Renaat Callens, Jeroen Van Stappen, Maxim Deprez, Veerle Cnudde, Nele De Belie
February 23, 2023 (v1)
Subject: Materials
Keywords: corrosion, cracking, electrochemical corrosion measurements, encapsulation, long term testing, self-healing, tomography, water repellent agent
Cracks in reinforced concrete are preferential ingress paths for aggressive substances such as chlorides. As soon as a critical amount of chlorides has reached the steel reinforcement, corrosion will occur. Therefore, crack healing is of utmost importance. However, manual crack repair is very labour intensive. Therefore, the potential of self-healing through the release of a water repellent agent from embedded capsules was compared with the effectiveness of applying this agent on the concrete surface before or after cracking and the effectiveness of injection of the agent into a crack. From the electrochemical corrosion measurements, it was shown that only uncracked samples were able to withstand 135 weekly cycles of exposure to a 33 g/L chloride solution without corrosion initiation of the reinforcement. While samples with manually injected and autonomously healed cracks resisted the exposure conditions for about 50 cycles or more, samples for which the water repellent agent was appli... [more]
Characteristics of Hydrochar and Liquid Products Obtained by Hydrothermal Carbonization and Wet Torrefaction of Poultry Litter in Mixture with Wood Sawdust
Rafail Isemin, Natalia Muratova, Sergey Kuzmin, Dmitry Klimov, Vadim Kokh-Tatarenko, Alexander Mikhalev, Oleg Milovanov, Antoine Dalibard, Olayinka Ahmed Ibitowa, Manuel Nowotny, Mathieu Brulé, Fouzi Tabet, Bernd Rogge
February 23, 2023 (v1)
Subject: Materials
Keywords: activated carbon, Biomass, fluidized bed, hydrothermal carbonization, steam torrefaction, waste treatment
Poultry farms with floor-standing poultry generate large amounts of poultry litter waste. The direct application of this waste as an organic fertilizer does not ensure sustainable and cost-efficient utilization of all waste fractions, and can also be linked to environmental hazards. Therefore, the development of new technologies is required for processing poultry litter into a safe product with higher added value. In this work, the characteristics of activated carbon derived from hydrochar, along with the liquid products obtained from hydrothermal carbonization (HTC) and the wet torrefaction (WT) of poultry litter, were investigated. Poultry litter (PL) was applied in a mixture with sawdust (SD) in the following ratios: 1:0 (PL/SD 1:0), 1:1 (PL/SD 1:1), 1:2 (PL/SD 1:2), and 2:1 (PL/SD 2:1). WT processing took place in an innovative fluidized bed system in a superheated steam medium with low overpressure (less than 0.07 MPa) at 300 °C and 350 °C for 30−45 min. Conventional HTC processin... [more]
A Comparison of Uric Acid Optical Detection Using as Sensitive Materials an Amino-Substituted Porphyrin and Its Nanomaterials with CuNPs, PtNPs and Pt@CuNPs
Camelia Epuran, Ion Fratilescu, Diana Anghel, Mihaela Birdeanu, Corina Orha, Eugenia Fagadar-Cosma
February 23, 2023 (v1)
Subject: Materials
Keywords: AFM, amino-substituted porphyrin, CuNPs, hybrid porphyrin nanomaterials, Pt@CuNPs, PtNPs, uric acid detection, UV-vis spectroscopy
Hybrid nanomaterials consisting in 5,10,15,20-tetrakis(4-amino-phenyl)-porphyrin (TAmPP) and copper nanoparticles (CuNPs), platinum nanoparticles (PtNPs), or both types (Pt@CuNPs) were obtained and tested for their capacity to optically detect uric acid from solutions. The introduction of diverse metal nanoparticles into the hybrid material proved their capacity to improve the detection range. The detection was monitored by using UV-Vis spectrophotometry, and differences between morphology of the materials were performed using atomic force microscopy (AFM). The hybrid material formed between porphyrin and PtNPs hasthe best and most stable response for uric acid detection in the range of 6.1958 × 10−6−1.5763 × 10−5 M, even in the presence of very high concentrations of the interference species present in human environment.
The Effect of PVA Binder Solvent Composition on the Microstructure and Electrical Properties of 0.98BaTiO3-0.02(Ba0.5Ca0.5)SiO3 Doped with Dy2O3
Nak-Beom Jo, Jin-Seok Baek, Eung-Soo Kim
February 23, 2023 (v1)
Subject: Materials
Keywords: BaTiO3-based ceramics, binder, electrical properties, MLCC
In this study, the effect of the polyvinyl alcohol (PVA) binder solvent composition on the electrical properties of sintered 0.98BaTiO3-0.02(Ba0.5Ca0.5)SiO3 ceramics doped with x wt.% Dy2O3 (0.0 ≤ x ≤ 0.3) was investigated. In the absence of the PVA binder, the specimens sintered at 1260 and 1320 °C for 1 h in a reducing atmosphere showed a single BaTiO3 phase with the perovskite structure. The relative densities of the specimens were higher than 90%, and the grain morphologies were uniform for all the solvent compositions. At 1 kHz, the dielectric constant of the specimens depended not only on their crystal structural characteristics, but also on their microstructural characteristics. The microstructural characteristics of the specimens with the PVA binder were affected by the ethyl alcohol:water ratio of the 10 wt.% PVA-111 solution. A homogeneous microstructure was observed for the 0.1 wt.% Dy2O3-doped specimens sintered at 1320 °C for 1 h when the ethyl alcohol/water ratio of the b... [more]
Towards High Efficiency CO2 Utilization by Glow Discharge Plasma
Stephan Renninger, Paul Rößner, Jan Stein, Maike Lambarth, Kai Peter Birke
February 23, 2023 (v1)
Subject: Materials
Keywords: CO2 electrolysis, CO2 splitting, CO2 utilization, Energy Efficiency, glow discharge, magnetic field, plasma catalysis, power-to-X
Plasma technology reaches rapidly increasing efficiency in catalytic applications. One such application is the splitting reaction of CO2 to oxygen and carbon monoxide. This reaction could be a cornerstone of power-to-X processes that utilize electricity to produce value-added compounds such as chemicals and fuels. However, it poses problems in practice due to its highly endothermal nature and challenging selectivity. In this communication a glow discharge plasma reactor is presented that achieves high energy efficiency in the CO2 splitting reaction. To achieve this, a magnetic field is used to increase the discharge volume. Combined with laminar gas flow, this leads to even energy distribution in the working gas. Thus, the reactor achieves very high energy efficiency of up to 45% while also reaching high CO2 conversion efficiency. These results are briefly explained and then compared to other plasma technologies. Lastly, cutting edge energy efficiencies of competing technologies such a... [more]
Adsorption of Cr(OH)n(3−n)+ (n = 1−3) on Illite (001) and (010) Surfaces: A DFT Study
Jia Du, Leilei Fan, Qinghe Wang, Fanfei Min
February 23, 2023 (v1)
Subject: Materials
Keywords: adsorption mechanism, DFT, hydroxyl chromium(III), illite
The development of clay adsorption materials with high Cr(III) removal capacities requires an understanding of the adsorption mechanism at the atomic level. Herein, the mechanisms for the adsorption of Cr(OH)2+, Cr(OH)2+, and Cr(OH)3 on the (001) and (010) surfaces of illite were studied by analyzing the adsorption energies, adsorption configurations, charges, and state densities using density functional theory (DFT). The adsorption energies on the illite (010) and (001) surfaces decrease in the order: Cr(OH)2+ > Cr(OH)2+ > Cr(OH)3. In addition, the energies associated with adsorption on the (010) surface are greater than those on the (001) surface. Further, the hydrolysates are highly active and can provide adsorption sites for desorption agents. The silica (Si−O) ring on the illite (001) surface can capture Cr(OH)n(3−n)+ (n = 1−3). In addition, both Cr(OH)2+ and Cr(OH)2+ form one covalent bond between Cr and surface OS1 (Cr−OS1), whereas the hydroxyl groups of Cr(OH)3 form three hydr... [more]
A Mini Review on Pyrolysis of Natural Algae for Bio-Fuel and Chemicals
Wei Xu, Keqiang Ding, Lihua Hu
February 23, 2023 (v1)
Subject: Materials
Keywords: bio-based chemicals, bio-fuel, Catalysis, natural algae, pyrolysis
The disposal and use of natural algae have recently been the subject of great interest, due to increasing concern for environmental protection and resource utilization. In this paper, a mini review of recent research on the pyrolysis of natural algae, especially the algae from water blooms, is presented. The chemical compositions of the natural algae are summarized, and the pyrolysis properties of different compositions are reviewed. Non-catalytic, catalytic, and integrated catalytic processes are reviewed. Different ideas and methods for the production of bio-fuel or chemicals are discussed. Apparently, deoxygenation and denitrogenation are highly necessary for algae-based bio-fuel and catalysts play an important role in these processes. In addition, the integrated catalytic process, which involves catalysis and other operation conditions aside from the thermal treatment under inert atmosphere, shows potential for the valorization of algae-based bio-oil. Based on the recent concept an... [more]
Impact of Various Essential Oils and Plant Extracts on the Characterization of the Composite Seaweed Hydrocolloid and Gac Pulp (Momordica cochinchinensis) Edible Film
Thuy Thi Bich Tran, Boi Ngoc Vu, Md Saifullah, Minh Huu Nguyen, Penta Pristijono, Timothy Kirkman, Quan Van Vuong
February 23, 2023 (v1)
Subject: Materials
Keywords: characterization, edible film, essential oils, plant extracts
Edible films and coatings have currently received increasing interest because of their potential in food applications. This study examined the effect of incorporated essential oils and natural plant extracts on the characteristics of the composite seaweed hydrocolloid and gac pulp films. Films were prepared by a casting technique, followed by measurement of physical, optical, barrier, mechanical, and structural properties. The results showed that adding plant oils and extracts significantly affected the physical, optical, mechanical, and structural properties of the composite films. Incorporation of the essential oils resulted in a reduction in moisture content and opacity while increasing values for Hue angle and elongation at break of the composite films. Besides, incorporation of the plant extracts showed increases in thickness, opacity, ΔE, Chroma, and elongation at the break, while there is a decrease in the Hue angle values of the composite films. In conclusion, incorporating pla... [more]
Mycotoxins—Prevention, Detection, Impact on Animal Health
Jagoda Kępińska-Pacelik, Wioletta Biel
February 23, 2023 (v1)
Subject: Materials
Keywords: aquaculture animals, companion animals, detection, farm animals, mycotoxin, prevention, safety
Mycotoxins are defined as secondary metabolites of some species of mold fungi. They are present in many foods consumed by animals. Moreover, they most often contaminate products of plant and animal origin. Fungi of genera Fusarium, Aspergillus, and Penicillum are most often responsible for the production of mycotoxins. They release toxic compounds that, when properly accumulated, can affect many aspects of breeding, such as reproduction and immunity, as well as the overall liver detoxification performance of animals. Mycotoxins, which are chemical compounds, are extremely difficult to remove due to their natural resistance to mechanical, thermal, and chemical factors. Modern methods of analysis allow the detection of the presence of mycotoxins and determine the level of contamination with them, both in raw materials and in foods. Various food processes that can affect mycotoxins include cleaning, grinding, brewing, cooking, baking, frying, flaking, and extrusion. Most feeding processes... [more]
Closed-Cell Powder Metallurgical Aluminium Foams Reinforced with 3 vol.% SiC and 3 vol.% Graphite
Jaroslav Kováčik, Martin Nosko, Natália Mináriková, František Simančík, Jaroslav Jerz
February 23, 2023 (v1)
Subject: Materials
Keywords: aluminium foams, closed-cell foam, composites, graphite discipline, powder metallurgy, silicon carbide
Closed-cell aluminium foams (nominal composition: AlSi12Mg0.6Fe0.3) were prepared by the powder metallurgical route (using 0.4 wt.% TiH2 untreated powder as the foaming agent). Pure foams and foams with the addition of 3 vol.% graphite or SiC powder were prepared. The microstructure and mechanical properties of the prepared aluminium foams containing reinforcing particles were investigated at constant density and compared to those of the pure foam. Vibration measurements were performed to determine the damping properties and modulus of elasticity of the foams. Uniaxial compression tests were performed to determine the following mechanical properties: collapse stress, efficiency of energy absorption, plateau length and densification strain of the foams. All the foams behaved in a brittle manner during compression. Finally, the effect of admixed graphite and SiC powders on the properties of the investigated foam was evaluated, discussed and modelled. The addition of powders changed all i... [more]
Facial Eco-Friendly Synthesis of Copper Oxide Nanoparticles Using Chia Seeds Extract and Evaluation of Its Electrochemical Activity
Noha Al-Qasmi
February 23, 2023 (v1)
Subject: Materials
Keywords: characterization, chia extract, CuO nanoparticles, green synthesis, metal oxide
In the current study, copper oxide nanoparticles (CuO NPs) were synthesized using chia seed extract in a simple, rapid, and eco-friendly manner for the first time. The synthesized CuO NPs were characterized using different analytical techniques. The images of field emission scanning electron microscopy revealed that the CuO NPs were triangular and pyramid in structure, with a mean particle size of 61.5 nm. The absorption peak of the synthesized CuO NPs was measured using ultraviolet-visible spectroscopy and was recorded at a wavelength of 291 nm. The results of energy-dispersive X-ray analysis confirmed that the CuO NPs synthesized using chia seed extract yielded high-purity CuO NPs. Moreover, the X-ray diffraction analysis indicated the highly crystalline nature of the CuO NPs, and the X-ray photoelectron spectroscopy results indicated that the CuO NPs were prepared successfully. Additionally, electrochemical impedance spectroscopy measurements revealed excellent electrocatalytic cond... [more]
Study of Natural Convection of Lithium-Ion Battery Module Employing Phase Change Material
Horng-Wen Wu, Yi-Chen Ciou, Jun-Kuan Wu, De-An Huang
February 23, 2023 (v1)
Subject: Materials
Keywords: distance between cells, fin array, heat transfer, Li-ion battery, natural convection, phase change material
When the Lithium-ion battery operates at high temperature, it would bring about short circuit; if it reaches a critical temperature, it will explode. It is important to reduce its maximum temperature by appropriate heat transfer technique. When it operates without an external force for cooling, it needs natural convection technique to take away heat dissipation. Therefore, this study numerically examines three-dimensional transient natural convection of cylindrical lithium-ion batteries inside a rectangular pack with air between cylinders. The heat transfer technique in this study applies PCM (phase change material) between cylinders without or with fin array on top changing distance between cells. The results indicated that for no fin array, the package adopting the PCM could achieve the peak temperature 14.2 °C smaller than the package adopting the air. However, the package adopting the PCM with fin array vertical to the top of the package can best enhance average Nusselt number by 1... [more]
In Situ Observation of the Carbothermic Reduction and Foaming of Slags in Silicomanganese Production
Vincent Canaguier, Merete Tangstad
February 23, 2023 (v1)
Subject: Materials
Keywords: ferroalloys, metallurgy, sessile drop technique, silicomanganese, slag foaming
The carbothermic reduction of slag in silicomanganese production is accompanied by the release of carbon monoxide. This gas can accumulate as bubbles within the slag, leading to foaming and, potentially, disturbances to furnace operation. This study investigated the reduction in the slag together with its foaming using a sessile drop furnace. Five silicomanganese slags produced from industrial raw materials (Assmang ore, Comilog ore, high-carbon FeMn slag with quartz, and FeS additions) were reduced by a graphite substrate at isothermal conditions (i.e., 1540−1660 °C) under CO atmosphere. The reduction reaction was tracked by photographing the slag droplet, and the cyclic expansion and burst of the droplet were used to estimate the gas evolution. The reacted samples were analyzed by wavelength-dispersive X-ray spectroscopy (WDS) to determine MnO and SiO2 reduction. While no foaming was observed using Comilog ore, extensive retention of CO in the slag phase was observed when using Assma... [more]
Development Strategy of Endodontic Filling Materials Based on Engineering and Medical Approaches
Leszek A. Dobrzański, Joanna Dobrzańska, Lech B. Dobrzański, Anna D. Dobrzańska-Danikiewicz, Klaudiusz Gołombek
February 23, 2023 (v1)
Subject: Materials
Keywords: cold side condensation, dental engineering, dentistry, endodontics, filling materials, gutta-percha, laser stereoscopic microscope, materials science and engineering, obturation, resilon, scanning electron microscope, sealants, thermo-hydraulic condensation technique, thermoplastic obturation
This article is a literature review aimed at presenting the general state of knowledge in manufacturing engineering and materials engineering to develop engineering materials applied for endodontic treatment as filling materials. Particular attention was paid to theoretical analyses concerning the selection of methods for developing and obturating root canals and discussing the results of experimental studies available in the literature. These activities aimed to compare the importance of the most commonly used endodontic filling materials based on gutta-percha or polymeric polyester materials, commonly known as resilon, respectively. The motivation to take up this complex, multi-faceted topic in this paper is the extent of caries, periodontal disease, and other oral diseases in 3 to 5 billion people, often affecting toothlessness and contributing to an increase in the index of disability-adjusted life years (number). Endodontics is an important element of the authors’ concept of Denti... [more]
Evaluation of a New Cerium Oxide-Bismuth Oxide-Based Nanobiocomposite as a Biocatalyst for Biodiesel Production
Anam Shahzadi, Muhammad Waseem Mumtaz, Hamid Mukhtar, Sadia Akram, Tooba Touqeer, Vasudeo Zambare, Lew Christopher
February 23, 2023 (v1)
Subject: Materials
Keywords: biodiesel, cerium doped bismuth oxide nanoparticles, fatty acid methyl esters, immobilization, lipase, response surface methodology
Biodiesel is a promising renewable energy source that can be used together with other biofuels to help meet the growing energy needs of the rapidly increasing global population in an environmentally friendly way. In search for new and more efficient biodiesel production methods, this work reports on the synthesis and use of a novel biocatalyst that can function in a broader range of pH and temperature conditions, while producing high biodiesel yields from vegetable oils. Biodiesel was synthesized by transesterification of non-edible Eruca sativa oil using a lipase from Aspergillus niger that was immobilized on cerium oxide bismuth oxide nanoparticles. The synthesized nanoparticles were first grafted with polydopamine which facilitated the subsequent anchoring of the enzyme on the nanoparticle support. The enzyme activity, pH and temperature stability, and reusability of the immobilized lipase were superior to those of the free enzyme. Following response surface methodology optimization... [more]
Liquid Chromatography Tandem Mass Spectrometric Analytical Method for Study of Colchicine in Rats Given Low Doses
Hamdah M. Al Nebaihi, Tyson S. Le, Neal M. Davies, Dion R. Brocks
February 23, 2023 (v1)
Subject: Materials
Keywords: colchicine, liquid-liquid extraction, low dose, pharmacokinetics, preclinical, small volume
A selective and sensitive assay was developed for colchicine in rat specimens. Colchicine and its deuterated analog (as internal standard, IS) were extracted from rat specimens (minimal 0.1 mL plasma, whole blood, or urine) using liquid-liquid extraction with n-hexane:dichloromethane:isopropanol. The mobile phase (formic acid: ammonium acetate: methanol) was pumped with uniform flow through an octadecylsilane analytical column. Detection was carried out by electrospray positive ionization in the multiple-reaction monitoring mode. The assay (total run time 96.8%. The intra- and inter-day coefficients of variation were ˂15%, with lower limits of quantitation of 0.5 ng/mL in 0.1 mL of rat plasma. The method also provided the same lower limits of quantitation in urine and whole blood with 0.1 mL volumes, and 0.1 ng/mL using 0.5 mL of rat plasma. The blood-to-plasma ratio was >1. Rats had measurable colchicine blood concentrations for at least 24 h after intravenous doses of 0.1 mg/kg. The... [more]
Comparative Study of Physicochemical Properties of Nanoemulsions Fabricated with Natural and Synthetic Surfactants
Karen Fuentes, Claudia Matamala, Nayaret Martínez, Rommy N. Zúñiga, Elizabeth Troncoso
February 23, 2023 (v1)
Subject: Materials
Keywords: droplet size, interfacial tension, O/W emulsions, rheology, stability, surfactants
This work aims to evaluate the effect of two natural (whey protein isolate, WPI, and soy lecithin) and a synthetic (Tween 20) emulsifier on physicochemical properties and physical stability of food grade nanoemulsions. Emulsions stabilized by these three surfactants and different sunflower oil contents (30% and 50% w/w), as the dispersed phase, were fabricated at two levels of homogenization pressure (500 and 1000 bar). Nanoemulsions were characterized for droplet size distribution, Zeta-potential, rheological properties, and physical stability. Dynamic light scattering showed that droplet size distributions and D50 values were strongly affected by the surfactant used and the oil content. WPI gave similar droplet diameters to Tween 20 and soy lecithin gave the larger diameters. The rheology of emulsions presented a Newtonian behavior, except for WPI-stabilized emulsions at 50% of oil, presenting a shear-thinning behavior. The physical stability of the emulsions depended on the surfacta... [more]
Testing the PTT Rheological Model for Extrusion of Virgin and Composite Materials in View of Enhanced Conductivity and Mechanical Recycling Potential
Mariya Edeleva, Dahang Tang, Tom Van Waeleghem, Flávio H. Marchesini, Ludwig Cardon, Dagmar R. D’hooge
February 23, 2023 (v1)
Subject: Materials
Keywords: composite design, extrusion process, polymer flow characterization, polymer stability
One of the challenges for the manufacturing processes of polymeric parts is the dedicated control of composite melt flow. In the present work, the predictive capability of the Phan-Thien-Tanner (PTT) viscoelastic model is evaluated in relation to the extrudate swell from slit dies at 200 °C, considering polypropylene and graphite filler, and applying ANSYS Polyflow software. It is shown that for sufficiently low filler amounts (below 10%; volumetric) the PTT accurately reflects the viscoelastic interactions, but at higher filler amounts too large swellings are predicted. One can although obtain insights on the swelling in the height direction and consider a broader range of swelling areas compared to virgin materials. Guidelines are also provided for future experiments and model development, including the omission of the no-slip process boundary condition.
Highly Stable and Nontoxic Lanthanum-Treated Activated Palygorskite for the Removal of Lake Water Phosphorus
Bhabananda Biswas, Ravi Naidu
February 23, 2023 (v1)
Subject: Materials
Keywords: Australian palygorskite, biocompatible material, modified clays, phosphate adsorption
Nutrient pollution of surface water, such as excess phosphate loading on lake surface water, is a significant issue that causes ecological and financial damage. Despite many technologies that can remove available phosphate, such as material-based adsorption of those available phosphate ions, the development of a material that can trap them from the surface water is worth doing, considering other aspects. These aspects are: (i) efficient adsorption by the material while it settles down to the water column, and (ii) the material itself is not toxic to the lake natural microorganism. Considering these aspects, we developed a trace lanthanum-grafted surface-modified palygorskite, a fibrous clay mineral. It adsorbed a realistic amount of phosphate from the lake water (typically 0.13−0.22 mg/L). The raw and modified palygorskite (Pal) includes unmodified Australian Pal, heated (at ~400 °C) Pal, and acid (with 3 M HCl)-treated Pal. Among them, while acid-treated Pal grafted a lower amount of... [more]
Recent Trends in Graphitic Carbon Nitride-Based Binary and Ternary Heterostructured Electrodes for Photoelectrochemical Water Splitting
Ravindranadh Koutavarapu, Shaik Gouse Peera, Tae Gwan Lee, Chimpiri Rao Myla, Dong-Yeon Lee, Jaesool Shim, Suresh Kannan Balasingam
February 23, 2023 (v1)
Subject: Materials
Keywords: binary and ternary heterostructures, g-C3N4, Hydrogen, photocatalyst, photoelectrochemical water splitting
The graphitic carbon nitride (g-C3N4) is a class of two-dimensional layered material. The ever-growing research on this fascinating material is due to its unique visible light absorption, surface, electrocatalytic, and other physicochemical properties that can be useful to different energy conversion and storage applications. Photoelectrochemical (PEC) water splitting reaction is one of the promising applications of g-C3N4, wherein it acts as a durable catalyst support material. Very recently, the construction of g-C3N4-based binary and ternary heterostructures exhibited superior PEC water splitting performance owing to its reduced reunion of e-/h+ pairs and the fast transfer of charge carriers at the heterostructure interface. This review compiles the recent advances and challenges on g-C3N4-based heterostructured photocatalysts for the PEC water splitting reaction. After an overview of the available literature, we presume that g-C3N4-based photocatalysts showed enhanced PEC water spl... [more]
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