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Records with Subject: Materials
Showing records 1 to 25 of 188. [First] Page: 1 2 3 4 5 Last
Effect of the Marangoni Convection in the Unsteady Thin Film Spray of CNT Nanofluids
Ali Rehman, Taza Gul, Zabidin Salleh, Safyan Mukhtar, Fawad Hussain, Kottakkaran Sooppy Nisar, Poom Kumam
August 15, 2019 (v1)
Subject: Materials
Keywords: extending cylinder, Marangoni convection, OHAM and ND-solve methods, SWCNT/MWCNT nanofluid
The gradient of surface temperature is known as Marangoni convection and plays an important role in silicon melt, spray, atomic reactors, and thin fluid films. Marangoni convection has been considered in the liquid film spray of carbon nanotube (CNT) nanofluid over the unsteady extending surface of a cylinder. The two kinds of CNTs, single-wall carbon nanotubes (SWCNTs) and multiple-wall carbon nanotubes (MWCNTs), formulated as water-based nanofluids have been used for thermal spray analysis. The thickness of the nanofluid film was kept variable for a stable spray rate and pressure distribution. The transformed equations of the flow problem have been solved using the optimal homotopy analysis method (OHAM). The obtained results have been validated through the sum of the total residual errors numerically and graphically for both types of nanofluids. The impact of the physical parameters versus velocity, pressure, and temperature pitches under the influence of the Marangoni convection ha... [more]
Increasing Iron and Reducing Phosphorus Grades of Magnetic-Roasted High-Phosphorus Oolitic Iron Ore by Low-Intensity Magnetic Separation−Reverse Flotation
Junhui Xiao, Lingli Zhou
August 15, 2019 (v1)
Subject: Materials
Keywords: iron increase, low-intensity magnetic separation, phosphorous reduction, phosphorus mineral flotation reagent, reverse flotation, suspended magnetic roast
High-phosphorus oolitic iron ore, treated by suspended flash magnetic roasting, contained 42.73% iron (mainly present as magnetite) and 0.93% phosphorus (present as collophane). Low-intensity magnetic separation (LIMS) was combined with reverse flotation to increase the iron and reduce the phosphorus contents of the roasted product. The results showed that an optimized iron ore concentrate with an iron grade of 67.54%, phosphorus content of 0.11%, and iron recovery of 78.99% were obtained under LIMS conditions that employed a grind of 95% −0.038 mm and a magnetic field of 0.10 T. Optimized rougher reverse-flotation conditions used a pulp pH of 9 and dosages of toluenesulfonamide, starch, and pine alcohol oil of 800 g/t, 1000 g/t, and 40 g/t, respectively; optimized scavenging conditions used a pulp pH of 9 and dosages of toluenesulfonamide, starch, and pine alcohol oil of 400 g/t, 500 g/t, and 20 g/t, respectively. Study of the mechanism of phosphorus reduction showed that the toluenes... [more]
Influence of Particle Charge and Size Distribution on Triboelectric Separation—New Evidence Revealed by In Situ Particle Size Measurements
Johann Landauer, Petra Foerst
August 15, 2019 (v1)
Subject: Materials
Keywords: binary mixture, charge estimation, in situ particle size measurement, particle charge, particle size distribution, triboelectric separation
Triboelectric charging is a potentially suitable tool for separating fine dry powders, but the charging process is not yet completely understood. Although physical descriptions of triboelectric charging have been proposed, these proposals generally assume the standard conditions of particles and surfaces without considering dispersity. To better understand the influence of particle charge on particle size distribution, we determined the in situ particle size in a protein−starch mixture injected into a separation chamber. The particle size distribution of the mixture was determined near the electrodes at different distances from the separation chamber inlet. The particle size decreased along both electrodes, indicating a higher protein than starch content near the electrodes. Moreover, the height distribution of the powder deposition and protein content along the electrodes were determined in further experiments, and the minimum charge of a particle that ensures its separation in a give... [more]
The Use of Polymers in the Flotation Treatment of Wastewater
Brian Bolto, Zongli Xie
August 14, 2019 (v1)
Subject: Materials
Keywords: flotation, hydrophobic polymers, oil recovery, polyelectrolyte, polymer, Wastewater
The use of flotation for the treatment of wastewaters in general, but especially for the removal of oil, grease, general organic matter, and suspended solids, is well established as a low energy process. Polyelectrolytes (PEs) can enhance performance without adding to the solids load that occurs with inorganic additives such as alum. The bridging of pollutants and the attachment of the resulting aggregates to the air-water interface can be effectively carried out with most wastewaters. Hydrophobic modification of the PEs can be useful for difficult species. It should be applied to the flotation of polyfluoroalkyl substances, for example, as they are not amenable to economical conventional treatment. Similarly, the removal of microplastic particles from sewage effluents by flotation could be enhanced.
Development and Permeability Testing of Self-Emulsifying Atorvastatin Calcium Pellets and Tablets of Compressed Pellets
Mine Diril, Yesim Karasulu, Miltiadis Toskas, Ioannis Nikolakakis
August 8, 2019 (v1)
Subject: Materials
Keywords: atorvastatin calcium, cytotoxicity, drug release, permeability, self-emulsifying pellets, self-emulsifying tablets
Self-emulsifying pellets (SEPs) of Atorvastatin Calcium (AtrCa) were developed and processed into tablets (SETs). Self-emulsifying drug delivery system (SEDDS) composed of oleic acid, Tween 20, Span 80 and N-Methyl-2-pyrolidone gave great solubility improvement and was used as oil in water emulsion for the preparation of SEPs. Due to the high 60% w/w SEDDS content required to achieve a therapeutic dose in the final tablet form, sonication was necessary to improve fluidity and stability. Colloidal silicon dioxide (CSD) and microcrystalline cellulose (MCC) were the solids in the pellet formulation employed at a ratio 7:3, which enabled production of pellets with high SEDDS content and acceptable friability as well. Emulsions were characterized physico-chemically, SEPs for physical properties and reconstitution, and tablets of compressed pellets for mechanical strength, disintegration into pellets and drug release. SEPs compressed with 30% MCC at 60 MPa gave tablets of adequate strength t... [more]
Effect of Heating Oxidation on the Surface/Interface Properties and Floatability of Anthracite Coal
Guoqiang Rong, Mengdi Xu, Dongyue Wang, Xiahui Gui, Yaowen Xing
August 8, 2019 (v1)
Subject: Materials
Keywords: bubble-particle wrap angle, floatability, heating oxidation, induction time, surface/interface properties
Oxidation processes of coal surfaces are both fundamental and interesting from academic and engineering points of view. In this work, we comprehensively analyzed the mechanism of heating oxidation at 200 °C on the surface/interface characters and the floatability of anthracite coal. The variations of surface/interface characters were studied using SEM (scanning electron microscopy), FTIR (Fourier transform infrared spectroscopy), and XPS (X-ray photoelectron spectroscopy). The floatability was further identified using Induction Time and Bubble-Particle Wrap Angle. It was found that, after heating oxidation at 200 °C, both surface ravines and oxygen-containing groups were increased. The degradation of hydroxyl on anthracite could be neglected during the heating, while the oxidation of hydrocarbon chains dominated the balance of hydrophobicity and hydrophilicity on coal surface. The induction time significantly increased from 200 ms to 1200 ms and 2000 ms after 10 h and 20 h of heating o... [more]
Biopolymer Solution Evaluation Methodology: Thermal and Mechanical Assessment for Enhanced Oil Recovery with High Salinity Brines
Mohammad A. Al-Saleh, Abdirahman A. Yussuf, Mohammad A. Jumaa, Abbas Hammoud, Tahani Al-Shammari
August 7, 2019 (v1)
Subject: Materials
Keywords: biopolymer, mechanical degradation, polymer flooding, rheology, thermal stability
The methodology to study an eco-friendly and non-toxic, Schizophyllan, biopolymer for enhanced oil recovery (EOR) polymer flooding is described. The methodology is divided into two parts; the first part estimates the molar concentration of the biopolymer, which is needed to prepare the biopolymer solution with optimal viscosity. This is required to improve the sweep efficiency for the selected reservoir in Kuwait. The second part of this generalized methodology evaluates the biopolymer solution capability to resist degradation and maintain its essential properties with the selected reservoir conditions. The evaluation process includes thermal and mechanical assessment. Furthermore, to study the biopolymer solution behavior in both selected reservoir and extreme conditions, the biopolymer solution samples were prepared using 180 g/L and 309 g/L brine. It was found that the prepared biopolymer solution demonstrated great capability in maintaining its properties; and therefore, can be int... [more]
Electrolyte Effects on Poly (Acrylic Acid)-Based Aircraft De-icing Fluids
Yuchen Wang, Nicholas E. Hudson, Richard A. Pethrick, Carl J. Schaschke
August 7, 2019 (v1)
Subject: Materials
Keywords: calcium and potassium ions, poly (acrylic acid), polyelectrolytes, rheology, salt effects, water/glycol mixtures
Poly (acrylic acid) [PAA]-based aircraft de-icing fluids are widely used commercially but are known to be subject to the formation of insoluble gel particles within wing structures. In this study, the rheological effects of the sodium chloride, potassium formate, and calcium acetate with commercially used PAA-based fluids are reported across the temperature range of −15 to 15 °C. Calcium ions have the potential to create gel particles, reflected in the shifts in the viscosity−temperature profile, while PAA aggregation is influenced by the concentrations and compositions of sodium and potassium salts in the water used for dilution. From the data presented, it is possible to create de-icing fluid formulations with the necessary rheological characteristics from stock solutions by dilution using available water sources, providing that the ion concentration is known.
Photocatalytic Treatment of Paracetamol Using TiO2 Nanotubes: Effect of pH
S. Alejandro Lozano-Morales, Graciela Morales, Miguel Ángel López Zavala, Augusto Arce-Sarria, Fiderman Machuca-Martínez
August 5, 2019 (v1)
Subject: Materials
Keywords: emerging contaminants, paracetamol, pH, photocatalysis, TiO2 nanotubes
Pharmaceuticals are considered among the group of emerging contaminants. Paracetamol is a moderate painkiller, which has been detected in ground and surface water. Photodegradation of paracetamol at a wavelength of radiation of 254 nm with TiO2 nanotubes was studied by UV-spectroscopy, HPLC and measurement of the potential zeta in dependence of the solution pH. The efficiency of the photodegradation of paracetamol (20 mg L−1) was 99% after 100 min exposure. Application of the Langmuir-Hinshelwood equation allowed the evaluation of the rate constant. Non-organic by-products were detected under the conditions of the chromatographic analysis. The photoreaction was faster at pH 6.5, a value at which adsorption was favored, leading to higher efficiency.
Comparative Study of the Performances of Al(OH)3 and BaSO4 in Ultrafine Powder Coatings
Weihong Li, Diego Cárdenas Franco, Marshall Shuai Yang, Xinping Zhu, Haiping Zhang, Yuanyuan Shao, Hui Zhang, Jingxu Zhu
July 31, 2019 (v1)
Subject: Materials
Keywords: Al(OH)3, BaSO4, filler, ultrafine powder coatings
Ultrafine powder coatings are one of the development directions in the powder coating industry, as they can achieve thin coatings with good leveling and high surface smoothness comparable to liquid coatings. Compared to regular coatings, they experience a higher sensitivity to any incompatibilities, e.g., filler from coating components. The properties of fillers play a great role in the performance of coating films. Aluminum trihydrate (Al(OH)3) is a well-known filler in solvent-based coatings and other polymer industries. To study and evaluate the performances of Al(OH)3 in ultrafine powder coatings, a popular filler, barium sulfate (BaSO4) is used for comparison. Both fillers are added in ultrafine powder coatings based on two of the most commonly used resin systems (polyester-epoxy and polyester). The differences of physical and chemical properties between both fillers have significant influences on several properties of powder paints and coating films. The polar groups (hydrogen bo... [more]
Hydroxymethylation-Modified Lignin and Its Effectiveness as a Filler in Rubber Composites
Nor Anizah Mohamad Aini, Nadras Othman, M. Hazwan Hussin, Kannika Sahakaro, Nabil Hayeemasae
July 31, 2019 (v1)
Subject: Materials
Keywords: bio-filler, hydroxymethylation, lignin, rubber composite
Kraft lignin was modified by using hydroxymethylation to enhance the compatibility between rubber based on a blend of natural rubber/polybutadiene rubber (NR/BR) and lignin. To confirm this modification, the resultant hydroxymethylated kraft lignin (HMKL) was characterized using Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy. It was then incorporated into rubber composites and compared with unmodified rubber. All rubber composites were investigated in terms of rheology, mechanical properties, aging, thermal properties, and morphology. The results show that the HMKL influenced the mechanical properties (tensile properties, hardness, and compression set) of NR/BR composites compared to unmodified lignin. Further evidence also revealed better dispersion and good interaction between the HMKL and the rubber matrix. Based on its performance in NR/BR composites, hydroxymethylated lignin can be used as a filler in the rubber industry.
Process Optimization by a Response Surface Methodology for Adsorption of Congo Red Dye onto Exfoliated Graphite-Decorated MnFe2O4 Nanocomposite: The Pivotal Role of Surface Chemistry
Van Thinh Pham, Hong-Tham T. Nguyen, Duyen Thi Cam Nguyen, Hanh T. N. Le, Thuong Thi Nguyen, Nhan Thi Hong Le, Kwon Teak Lim, Trinh Duy Nguyen, Thuan Van Tran, Long Giang Bach
July 31, 2019 (v1)
Subject: Materials
Keywords: Boehm titration, Congo red decontamination, exfoliated graphite, MnFe2O4 nanoparticles, response surface methodology, surface functional groups
Natural graphite, a locally available, eco-friendly, and low-cost carbonaceous source, can be easily transformed into exfoliated graphite (EG) with many surface functional groups via a chemical oxidation route. Combination between EG and magnetic MnFe2O4 is a promising strategy to create a hybrid kind of nanocomposite (EG@MnFe2O4) for the efficient adsorptive removal of Congo red (CR) dye from water. Here, we reported the facile synthesis and characterization of chemical bonds of EG@MnFe2O4 using several techniques such as Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). In particular, the quantity method by Boehm titration was employed to identify the content of functional groups: Carboxylic acid (0.044 mmol/g), phenol (0.032 mmol/g), lactone (0.020 mmol/g), and total base (0.0156 mmol/g) on the surface of EG@MnFe2O4. Through the response surface methodology-optimized models, we found a clear difference in the adsorption capacity between EG-... [more]
Using a Microfluidics System to Reproducibly Synthesize Protein Nanoparticles: Factors Contributing to Size, Homogeneity, and Stability
Courtney van Ballegooie, Alice Man, Irene Andreu, Byron D. Gates, Donald Yapp
July 31, 2019 (v1)
Subject: Materials
Keywords: delivery systems, microfluidic coprecipitation, pharmaceutics, syringe pump, zein nanoparticles
The synthesis of Zein nanoparticles (NPs) using conventional methods, such as emulsion solvent diffusion and emulsion solvent evaporation, is often unreliable in replicating particle size and polydispersity between batch-to-batch syntheses. We have systematically examined the parameters for reproducibly synthesizing Zein NPs using a Y-junction microfluidics chip with staggered herringbone micromixers. Our results indicate that the total flow rate of the fluidics system, relative flow rate of the aqueous and organic phase, concentration of the base material and solvent, and properties of the solvent influence the polydispersity and size of the NPs. Trends such as increasing the total flow rate and relative flow rate lead to a decrease in Zein NP size, while increasing the ethanol and Zein concentration lead to an increase in Zein NP size. The solvent property that was found to impact the size of the Zein NPs formed the most was their hydropathy. Solvents that had a hydropathy index most... [more]
On Molecular Descriptors of Face-Centered Cubic Lattice
Hong Yang, Muhammad Aamer Rashid, Sarfraz Ahmad, Saima Sami Khan, Muhammad Kamran Siddiqui
July 30, 2019 (v1)
Subject: Materials
Keywords: atom–bond connectivity index, Balaban index, face-centered cubic lattice FCC(n), forgotten index, geometric arithmetic index, Zagreb-type indices
Face-centered cubic lattice F C C ( n ) has received extensive consideration as of late, inferable from its recognized properties and non-poisonous nature, minimal effort, plenitude, and basic creation process. The graph of a face-centered cubic cross-section contains cube points and face centres. A topological index of a molecular graph G is a numeric amount identified with G, which depicts its topological properties. In this paper, using graph theory tools, we computed the molecular descriptors (topological indices)—to be specific, Zagreb-type indices, a forgotten index, a Balaban index, the fourth version of an atom−bond connectivity index, and the fifth version of a geometric arithmetic index for face-centered cubic lattice F C C ( n ) .
Co3O4/g-C3N4 Hybrids for Gas-Phase Hg0 Removal at Low Temperature
Zhen Zhang, Jiang Wu, Dongjing Liu
July 30, 2019 (v1)
Subject: Materials
Keywords: carbon nitride nanosheet, cobalt oxide, elemental mercury, mercury removal
The Co3O4/g-C3N4 hybrids are constructed via the incipient wetness impregnation method by depositing Co3O4 onto the exterior of g-C3N4, and then employed for Hg0 capture within 60−240 °C. The results show that the Co3O4/g-C3N4 hybrid with a Co3O4 content of 12 wt% performs optimally with the highest Hg0 removal efficiency of ~100% at or above 120 °C. The high performances of the Co3O4/g-C3N4 hybrids are probably attributed to the tight interfacial contact between Co3O4 and g-C3N4, with its improved electron transfer, inferring that cobalt oxide and g-C3N4 display a cooperative effect towards Hg0 removal. NO and SO2 shows a significant suppressive influence on the mercury capture performance, plausibly owing to the competing adsorption and side reactions.
Exploring New Crystal Structures of Glycine via Electric Field-Induced Structural Transformations with Molecular Dynamics Simulations
Pelin Su Bulutoglu, Conor Parks, Nandkishor K. Nere, Shailendra Bordawekar, Doraiswami Ramkrishna
July 30, 2019 (v1)
Subject: Materials
Keywords: crystal structure, electric fields, molecular dynamics, polymorph control, polymorphism
Being able to control polymorphism of a crystal is of great importance to many industries, including the pharmaceutical industry, since the crystal’s structure determines significant physical properties of a material. While there are many conventional methods used to control the final crystal structure that comes out of a crystallization unit, these methods fail to go beyond a few known structures that are kinetically accessible. Recent studies have shown that externally applied fields have the potential to effectively control polymorphism and to extend the set of observable polymorphs that are not accessible through conventional methods. This computational study focuses on the application of high-intensity dc electric fields (e-fields) to induce solid-state transformation of glycine crystals to obtain new polymorphs that have not been observed via experiments. Through molecular dynamics simulations of solid-state α -, β -, and γ -glycine crystals, it has been shown that... [more]
Microstructure and Resistivity Analysis of Silver Nanoparticle-Based Crystalline Conductive Films Synthesized using PEG Surfactant
Faisal Mustafa, Muhammad Razwan, Saima Shabbir
July 28, 2019 (v1)
Subject: Materials
Keywords: PEG, resistivity, silver nanoparticles, surfactant
Silver nanoparticle-based crystalline conductive films were synthesized using a simple and environmentally friendly method centered on chemical reduction. A stoichiometric balance of three different molecular weights of polyethylene glycol (PEG) was used as a capping agent. Resistivity, and its correlation with temperature and the particle size of nanoparticle films, was probed. The silver nanoparticles were characterized using thermogravimetric analysis (TGA) and field emission scanning electron microscopy (FESEM). Further silver films deposited on a glass substrate were characterized by FESEM, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and resistivity measurements. Particle size distribution and room temperature electrical conductivity were also investigated. The high conductivity of sintered films suggested applications for the ink-jet printing of electronic circuitry on thermally sensitive substrates.
Effect of Thermal-Electric Cross Coupling on Heat Transport in Nanofluids
Zhanxiao Kang, Liqiu Wang
July 26, 2019 (v1)
Subject: Materials
Keywords: electric field, heat transport enhancement, nanofluids, thermal motion, thermal-electric cross coupling
Nanofluids have an enhanced thermal conductivity compared with their base fluid. Although many mechanisms have been proposed, few of them could give a satisfactory explanation of experimental data. In this study, a mechanism of heat transport enhancement is proposed based on the cross coupling of thermal and electric transports in nanofluids. Nanoparticles are viewed as large molecules which have thermal motion together with the molecules of the base fluid. As the nanoparticles have surface charges, the motion of nanoparticles in the high-temperature region will generate a relatively strong varying electric field through which the motion will be transported to other nanoparticles, leading to a simultaneous temperature rise of low-temperature nanoparticles. The local base fluid will thus be heated up by these nanoparticles through molecular collision. Every nanoparticle could, therefore, be considered as an internal heat source, thereby enhancing the equivalent thermal conductivity sign... [more]
Evaluating the Degradation Mechanism and State of Health of LiFePO₄ Lithium-Ion Batteries in Real-World Plug-in Hybrid Electric Vehicles Application for Different Ageing Paths
Chi Zhang, Fuwu Yan, Changqing Du, Jianqiang Kang, Richard Fiifi Turkson
July 26, 2019 (v1)
Subject: Materials
Keywords: aging mechanism, capacity fading, differential voltage analysis, lithium-ion batteries, peak power capacity
Accurate determination of the performance and precise prediction of the state of health (SOH) of lithium-ion batteries are necessary to ensure reliability and efficiency in real-world application. However, most SOH offline studies were based on dynamic stress tests, which only reflect the universal rule of degradation, but are not necessarily applicable for real-world applications. This paper presents an experimental evaluation of two different operations of real-world plug-in hybrid electric vehicles with LiFePO₄ batteries as energy-storage systems. First, the LiFePO₄ batteries were subjected to a set of comparative experimental tests that consider the effects of charge depleting (CD) and charge sustaining (CS) operations. Then, different voltage analysis along with the close-to-equilibrium open circle voltage was utilized to evaluate the performance of the batteries in life cycles. Finally, a qualitative relationship between the external factors (the percentage of time of CD/CS opera... [more]
Fire Hazards of Some Modern Solid Fuels
Vasily Novozhilov
July 26, 2019 (v1)
Subject: Materials
Keywords: biomass fuels, fire hazard, flashover
Fire hazard during ship transportation of certain modern solid fuels is identified. A particular mechanism which may lead to catastrophic ship fire is discussed. A mathematical model predicting time to such fully developed fire (flashover time) I s proposed. An analytical solution is obtained for the developed model. An important part of this solution is a closed form analytical description of the smoke filling dynamics in a closed compartment. It is demonstrated that flashover time depends on a number of parameters. The relative importance of these parameters is discussed. Particular significance is attributed to fuel soot propensity (fuel soot yield) which is an intrinsic fuel property. This parameter controls the intensity of radiative heat exchange in the compartment, and its influence on flashover time is of paramount importance. It is suggested that fuels are ranked with respect to this parameter in order to describe their relative fire hazards. This ranking should be implemented... [more]
Thermochemical Storage of Middle Temperature Wasted Heat by Functionalized C/Mg(OH)₂ Hybrid Materials
Emanuela Mastronardo, Yukitaka Kato, Lucio Bonaccorsi, Elpida Piperopoulos, Candida Milone
July 26, 2019 (v1)
Subject: Materials
Keywords: carbon nanotubes, exfoliated graphite, graphene oxide, magnesium hydroxide, thermochemical storage
For the thermochemical performance implementation of Mg(OH)₂ as a heat storage medium, several hybrid materials have been investigated. For this study, high-performance hybrid materials have been developed by exploiting the authors’ previous findings. Expanded graphite (EG)/carbon nanotubes (CNTs)-Mg(OH)₂ hybrid materials have been prepared through Mg(OH)₂ deposition-precipitation over functionalized, i.e., oxidized, or un-functionalized EG or CNTs. The heat storage performances of the carbon-based hybrid materials have been investigated through a laboratory-scale experimental simulation of the heat storage/release cycles, carried out by a thermogravimetric apparatus. This study offers a critical evaluation of the thermochemical performances of developed materials through their comparison in terms of heat storage and output capacities per mass and volume unit. It was demonstrated that both EG and CNTs improves the thermochemical performances of the storage medium in terms of reaction r... [more]
Multi-Objective Optimization of Thin-Film Silicon Solar Cells with Metallic and Dielectric Nanoparticles
Giovanni Aiello, Salvatore Alfonzetti, Santi Agatino Rizzo, Nunzio Salerno
July 26, 2019 (v1)
Subject: Materials
Keywords: evolutionary algorithms, finite element method, nanoplamonics, Optimization, Renewable and Sustainable Energy, solar cell
Thin-film solar cells enable a strong reduction of the amount of silicon needed to produce photovoltaic panels but their efficiency lowers. Placing metallic or dielectric nanoparticles over the silicon substrate increases the light trapping into the panel thanks to the plasmonic scattering from nanoparticles at the surface of the cell. The goal of this paper is to optimize the geometry of a thin-film solar cell with silver and silica nanoparticles in order to improve its efficiency, taking into account the amount of silver. An efficient evolutionary algorithm is applied to perform the optimization with a reduced computing time.
Pt-Ni and Pt-M-Ni (M = Ru, Sn) Anode Catalysts for Low-Temperature Acidic Direct Alcohol Fuel Cells: A Review
Ermete Antolini
July 26, 2019 (v1)
Subject: Materials
Keywords: direct ethanol fuel cells, direct methanol fuel cells, ethanol oxidation, methanol oxidation, Pt-Ni
In view of a possible use as anode materials in acidic direct alcohol fuel cells, the electro-catalytic activity of Pt-Ni and Pt-M-Ni (M = Ru, Sn) catalysts for methanol and ethanol oxidation has been widely investigated. An overview of literature data regarding the effect of the addition of Ni to Pt and Pt-M on the methanol and ethanol oxidation activity in acid environment of the resulting binary and ternary Ni-containing Pt-based catalysts is presented, highlighting the effect of alloyed and non-alloyed nickel on the catalytic activity of these materials.
Enhancement Effect of Ordered Hierarchical Pore Configuration on SO2 Adsorption and Desorption Process
Yuwen Zhu, Yanfang Miao, Haoyu Li
July 25, 2019 (v1)
Subject: Materials
Keywords: Adsorption, hierarchical pore structure, ordered mesopores, regeneration, SO2
Carbonaceous adsorbents with both high sulfur capacity and easy regeneration are required for flue gas desulfurization. A hierarchical structure is desirable for SO2 removal, since the micropores are beneficial for SO2 adsorption, while the mesopore networks facilitate gas diffusion and end-product H2SO4 storage. Herein, an ordered hierarchical porous carbon was synthesized via a soft-template method and subsequent activation, used in SO2 removal, and compared with coal-based activated carbon, which also had a hierarchical pore configuration. The more detailed, abundant micropores created in CO2 activation, especially the ultramicropores (d < 0.7 nm), are essential in enhancing the SO2 adsorption and the reserves rather than the pore patterns. While O2 and H2O participate in the reaction, the hierarchical porous carbon with ordered mesopores greatly improves SO2 removal dynamics and sulfur capacity, as this interconnecting pore pattern facilitates H2SO4 transport from micropores to... [more]
Effect of Nitric Acid Modification on Characteristics and Adsorption Properties of Lignite
Bo Huang, Guowei Liu, Penghui Wang, Xiang Zhao, Hongxiang Xu
July 25, 2019 (v1)
Subject: Materials
Keywords: adsorption performance, lignite, nitric acid modification, pore structure, surface characteristics
The objective of this research was to explore the changes of the pore structure and surface properties of nitric-modified lignite and base the adsorption performance on physical and chemical adsorbent characteristics. To systematically evaluate pore structure and surface chemistry effects, several lignite samples were treated with different concentrations of nitric acid in order to get different pore structure and surface chemistry adsorbent levels. A common heavy metal ion contaminant in water, Pb2+, served as an adsorbate probe to demonstrate the change of modified lignite adsorption properties. The pore structure and surface properties of lignite samples before and after modification were characterized by static nitrogen adsorption, X-ray diffraction, Scanning electron microscope, Fourier transform infrared spectroscopy, zeta potential, and X-ray photoelectron spectroscopy. The experimental results showed that nitric acid modification can increase the ability of lignite to adsorb Pb... [more]
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