Browse
Subjects
Records with Subject: Materials
Showing records 1 to 25 of 475. [First] Page: 1 2 3 4 5 Last
Development of Poly(L-Lactic Acid)/Chitosan/Basil Oil Active Packaging Films via a Melt-Extrusion Process Using Novel Chitosan/Basil Oil Blends
Constantinos E. Salmas, Aris E. Giannakas, Maria Baikousi, Areti Leontiou, Zoe Siasou, Michael A. Karakassides
October 14, 2021 (v1)
Subject: Materials
Keywords: active packaging, antioxidant properties, barrier properties, basil oil, chitosan, films, PLLA
Following the global trend toward a cyclic economy, the development of a fully biodegradable active packaging film is the target of this work. An innovative process to improve the mechanical, antioxidant, and barrier properties of Poly(L-Lactic Acid)/Chitosan films is presented using essential basil oil extract. A Chitosan/Basil oil blend was prepared via a green evaporation/adsorption method as a precursor for the development of the Poly(L-Lactic Acid)/Chitosan/Basil Oil active packaging film. This Chitosan/Basil Oil blend was incorporated directly in the Poly(L-Lactic Acid) matrix with various concentrations. Modification of the chitosan with the Basil Oil improves the blending with the Poly(L-Lactic Acid) matrix via a melt-extrusion process. The obtained Poly(L-Lactic Acid)/Chitosan/Basil Oil composite films exhibited advanced food packaging properties compared to those of the Poly(L-Lactic Acid)/Chitosan films without Basil Oil addition. The films with 5%wt and 10%wt Chitosan/Basil... [more]
Pyrometallurgical Lithium-Ion-Battery Recycling: Approach to Limiting Lithium Slagging with the InduRed Reactor Concept
Stefan Windisch-Kern, Alexandra Holzer, Christoph Ponak, Harald Raupenstrauch
October 14, 2021 (v1)
Subject: Materials
Keywords: carbothermal reduction, lithium-ion-batteries, pyrometallurgical recycling
The complexity of the waste stream of spent lithium-ion batteries poses numerous challenges on the recycling industry. Pyrometallurgical recycling processes have a lot of benefits but are not able to recover lithium from the black matter since lithium is slagged due to its high oxygen affinity. The presented InduRed reactor concept might be a promising novel approach, since it does not have this disadvantage and is very flexible concerning the chemical composition of the input material. To prove its basic suitability for black matter processing, heating microscope experiments, thermogravimetric analysis and differential scanning calorimetry have been conducted to characterize the behavior of nickel rich cathode materials (LiNi0.8Co0.15Al0.05O2 and LiNi0.33Mn0.33Co0.33O2) as well as black matter from a pretreatment process under reducing conditions. Another experimental series in a lab scale InduRed reactor was further used to investigate achievable transfer coefficients for the metals... [more]
Films and Materials Derived from Aminomalononitrile
Helmut Thissen, Richard A. Evans, Vincent Ball
October 14, 2021 (v1)
Subject: Materials
Keywords: aminomalononitrile, biomaterials, prebiotic chemistry, versatile coatings
In recent years major advances in surface chemistry and surface functionalization have been performed through the development, most often inspired by living organisms, of versatile methodologies. Among those, the contact of substrates with aminomalononitrile (AMN) containing solutions at pH = 8.5 allows a conformal coating to be deposited on the surface of all known classes of material. Since AMN is a molecule probably formed in the early atmosphere of our planet and since HCN-based compounds have been detected on many comets and Titan (Saturn’s largest moon) it is likely that such molecules will open a large avenue in surface functionalization mostly for bio-applications. This mini review describes the state of the art of AMN-based coatings from their deposition kinetics, composition, chemical reactivity, hypothetical structure to their first applications as biomaterials. Finally, the AMN-based versatile coatings are compared to other kinds of versatile coating based on catecholamines... [more]
Optimization Studies of AC4CH Material in the Cylinder Block of a Diesel Engine Application
Bum Youl Park, Youngkun Kim, Kihyung Lee
October 14, 2021 (v1)
Subject: Materials
Keywords: AC4CH, diesel engine, refinement, weight reduction
The reduction of the weight of the engine of a vessel or an automobile can result in improved engine efficiency and lower CO2 emissions. Therefore, this study was conducted to improve the mechanical properties of the AC4CH alloy, an alternative to cast iron for engine fabrication, through the addition of Si and Mg to aluminum. The mechanical properties of the alloy were improved through refinement of the Si structure, grain refinement, and heat treatment. In addition, the applicability of a cylinder block fabricated with the modified AC4CH alloy to a diesel engine was validated through a 300 h durability test.
Graphitic Carbon Nitride-Based Composite in Advanced Oxidation Processes for Aqueous Organic Pollutants Removal: A Review
Yu Shen, Antonio J. Dos santos-Garcia, María José Martín de Vidales
October 14, 2021 (v1)
Subject: Materials
Keywords: advanced oxidation processes, aqueous organic pollutants removal, graphitic carbon nitride
In recent decades, a growing number of organic pollutants released have raised worldwide concern. Graphitic carbon nitride (g-C3N4) has drawn increasing attention in environmental pollutants removal thanks to its unique electronic band structure and excellent physicochemical stability. This paper reviews the recent progress of g-C3N4-based composites as catalysts in various advanced oxidation processes (AOPs), including chemical, photochemical, and electrochemical AOPs. Strategies for enhancing catalytic performance such as element-doping, nanostructure design, and heterojunction construction are summarized in detail. The catalytic degradation mechanisms are also discussed briefly.
Kanchan Arsenic Filters and the Future of Fe0-Based Filtration Systems for Single Household Drinking Water Supply
Zhe Huang, Viet Cao, Esther Laurentine Nya, Willis Gwenzi, Chicgoua Noubactep
October 11, 2021 (v1)
Subject: Materials
Keywords: arsenic removal, groundwater contamination, household filter, removal efficiency, zero-valent iron
Biological and chemical contamination of natural water bodies is a global health risk for more than one billion people, mostly living in low-income countries. Innovative, affordable, and efficient decentralized solutions for safe drinking water supply are urgently needed. Metallic iron (Fe0)-based filtration systems have been described as such an appropriate solution. This communication focuses on the Kanchan arsenic filter (KAF), presented in the early 2000s and widely assessed during the past decade. The KAF contains iron nails as the Fe0 source and is primarily designed to remove As from polluted tube well waters. Recent independent works assessing their performance have all reported on a high degree of variability in efficiency depending mostly on the following factors: (1) the current operating conditions, (2) the design, and (3) the groundwater chemistry. This communication shows that the major problems of the KAF are two-fold: (1) a design mistake as the Fe0 units disturb the op... [more]
Tribological Properties of Additive Manufactured Materials for Energy Applications: A Review
Alessandro M. Ralls, Pankaj Kumar, Pradeep L. Menezes
September 21, 2021 (v1)
Subject: Materials
Keywords: additive manufacturing, energy applications, manufacturing, mechanical properties, metals, surface roughness, tribology
Recently, additive manufacturing (AM) has gained much traction due to its processing advantages over traditional manufacturing methods. However, there are limited studies which focus on process optimization for surface quality of AM materials, which can dictate mechanical, thermal, and tribological performance. For example, in heat-transfer applications, increased surface quality is advantageous for reducing wear rates of vibrating tubes as well as increasing the heat-transfer rates of contacting systems. Although many post-processing and in situ manufacturing techniques are used in conjunction with AM techniques to improve surface quality, these processes are costly and time-consuming compared to optimized processing techniques. With improved as-built surface quality, particles tend to be better fused, which allows for greater wear resistance from contacting tube surfaces. Additionally, improved surface quality can reduce the entropy and exergy generated from flowing fluids, in turn i... [more]
Comparative Analysis of the Behaviour of Marine Litter in Thermochemical Waste Treatment Processes
Johann Hee, Kai Schlögel, Simone Lechthaler, Jacqueline Plaster, Kristina Bitter, Lars Mathias Blank, Peter Quicker
September 16, 2021 (v1)
Subject: Materials
Keywords: biotechnological upcycling, gasification, incineration, marine litter, plastic waste, plastics recycling, pyrolysis, thermogravimetric analysis, waste treatment
Plastic in the ocean, especially plastic on the ocean surface is not only researched intensively but also photos and reports rise awareness of the challenge in the general public. While research is concerned with the fate of marine litter in the environment, recycling of these materials after collection is rarely addressed, mainly because there is neither considerable data on composition nor a suggested process to do so. This study is the first to analyse and evaluate chemical recycling (pyrolysis, gasification) and energy recovery (incineration) of marine litter. Two heterogenous marine litter samples from Sylt and Norderney, North Sea, Germany, were analysed, consisting of six different material groups. Agricultural mulch foil was used as reference material. The thermochemical treatment processes were reproduced by thermogravimetric analysis. Furthermore, pyrolysis trials on a semi-technical scale were conducted and the residues were analysed by proximate, ultimate and X-ray fluoresc... [more]
Microscopic Characteristics and Properties of Fe-Based Amorphous Alloy Compound Reinforced WC-Co-Based Coating via Plasma Spray Welding
Yan Xu, Yinfeng Wang, Yi Xu, Mingyong Li, Zheng Hu
August 2, 2021 (v1)
Subject: Materials
Keywords: Fe-based amorphous alloy, microstructure and properties, plasma spray welding, WC-Co coating
Plasma spray welding, as one of the material surface strengthening techniques, has the advantages of low alloy material consumption, high mechanical properties and good coating compactness. Here, the Co alloy, WC and Fe-based amorphous alloy composite coating is prepared by the plasma spray welding method, and the coating characteristics are investigated. The results indicate that the coatings have a full metallurgical bond in the coating/substrate interface, and the powder composition influences the microstructures and properties of the coating. The hardness of coatings increases with the mass fraction of the Fe-based amorphous alloy. The spray welding layer has a much higher wear resistance compared with the carbon steel, and the Fe-20 exhibits a superior wear resistance when compared to others. The results indicate that the amorphous alloy powders are an effective additive to prepare the coating by plasma spray welding for improving the wear resistance of the coating.
Time of Flight Size Control of Carbon Nanoparticles Using Ar+CH4 Multi-Hollow Discharge Plasma Chemical Vapor Deposition Method
Sung Hwa Hwang, Kazunori Koga, Yuan Hao, Pankaj Attri, Takamasa Okumura, Kunihiro Kamataki, Naho Itagaki, Masaharu Shiratani, Jun-Seok Oh, Susumu Takabayashi, Tatsuyuki Nakatani
August 2, 2021 (v1)
Subject: Materials
Keywords: carbon nanoparticle, coagulation, optical emission spectroscopy, plasma chemical vapor deposition
As the application of nanotechnology increases continuously, the need for controlled size nanoparticles also increases. Therefore, in this work, we discussed the growth mechanism of carbon nanoparticles generated in Ar+CH4 multi-hollow discharge plasmas. Using the plasmas, we succeeded in continuous generation of hydrogenated amorphous carbon nanoparticles with controlled size (25−220 nm) by the gas flow. Among the nanoparticle growth processes in plasmas, we confirmed the deposition of carbon-related radicals was the dominant process for the method. The size of nanoparticles was proportional to the gas residence time in holes of the discharge electrode. The radical deposition developed the nucleated nanoparticles during their transport in discharges, and the time of flight in discharges controlled the size of nanoparticles.
Ultrasonically Induced Polymerization and Polymer Grafting in the Presence of Carbonaceous Nanoparticles
Sarah Cohen, Evgeni Zelikman, Ran Yosef Suckeveriene
July 29, 2021 (v1)
Subject: Materials
Keywords: grafting, nanoparticles, polymerization, sonochemistry
Nanotechnology refers to technologies using at least one nanometric dimension. Most advances have been in the field of nanomaterials used in research and industry. The vast potential of polymeric nanocomposites for advanced materials and applications such as hybrid nanocomposites with customized electrical conductivity, anti-bacterial, anti-viral, and anti-fog properties have attracted considerable attention. The number of studies on the preparation of nanocomposites in the presence of carbon materials, i.e., carbon nanotubes (CNTs) and graphene, has intensified over the last decade with the growing interest in their outstanding synergic properties. However, the functionality of such nanocomposites depends on overcoming three key challenges: (a) the breakdown of nanoparticle agglomerates; (b) the attachment of functional materials to the nanoparticle surfaces; and (c) the fine dispersion of functional nanoparticles within the polymeric matrices. Ultrasonic polymerization and grafting i... [more]
Experimental Study on the Flow and Heat Transfer of Graphene-Based Lubricants in a Horizontal Tube
Zhongpan Cai, Maocheng Tian, Guanmin Zhang
July 29, 2021 (v1)
Subject: Materials
Keywords: convection heat transfer, graphene, nanofluid, thermal conductivity
To improve the heat transfer characteristics of lubricant, graphene-based lubricants were prepared by adding graphene particles, due to its advantages of excellent thermal conductivity and two-dimensional sheet structure. In the present study, its physical properties were measured. A flow heat transfer experiment platform was built to study the flow and heat transfer characteristics of the graphene lubricating oil in a horizontal circular tube. The results show that the graphene lubricant prepared using a two-step approach had good stability, and the dispersibility was good without the agglomeration phenomenon, according to measurements undertaken using an electron microscope and centrifuge. The thermal conductivity and viscosity of graphene lubricant increased with the increase of the graphene concentration, and the thermal conductivity of graphene lubricant with the same concentration decreased with the increase of temperature. When the concentration was equal, the convective heat tr... [more]
Review on Carbon Nanotube Varieties for Healthcare Application: Effect of Preparation Methods and Mechanism Insight
Jothi Ramalingam Rajabathar, Govindasami Periyasami, Amer M. Alanazi, Mani Govindasamy, Prabhakarn Arunachalam
July 29, 2021 (v1)
Subject: Materials
Keywords: carbon electrodes, carbon nanotube, catalyst, E. coli, graphene oxide, single wall carbon
Many potential uses of carbon nanotubes (CNT) in various sectors have created an urge to assess their diverse range of properties pertaining to various applications like catalysis, biosensor, and antimicrobial activity. Increasing studies on the biosensor and antibacterial activity of CNT have prompted tremendous interest in the utilization of the carbon-based nanostructured material as an alternative to currently existing antibiotics. However, the study of bactericidal aspects of this nanomaterial is relatively new and hence the deeper understanding of the various physicochemical characteristics and antimicrobial nature of CNT is extremely wanted. This review covers the effect of framework substitution and explains the understanding of membrane disintegration and oxidative stresses upon nanomaterials for antimicrobial activity. The present article has also reviewed effect of preparation nanoparticle deposition and framework modification on carbon nanotube structure. The recent researc... [more]
Current State of Porous Carbon for Wastewater Treatment
Mongi ben Mosbah, Lassaad Mechi, Ramzi Khiari, Younes Moussaoui
July 29, 2021 (v1)
Subject: Materials
Keywords: activated carbon, activating agent, Adsorption, applications, Biomass, pollutants, porous materials
Porous materials constitute an attractive research field due to their high specific surfaces; high chemical stabilities; abundant pores; special electrical, optical, thermal, and mechanical properties; and their often higher reactivities. These materials are currently generating a great deal of enthusiasm, and they have been used in large and diverse applications, such as those relating to sensors and biosensors, catalysis and biocatalysis, separation and purification techniques, acoustic and electrical insulation, transport gas or charged species, drug delivery, and electrochemistry. Porous carbons are an important class of porous materials that have grown rapidly in recent years. They have the advantages of a tunable pore structure, good physical and chemical stability, a variable specific surface, and the possibility of easy functionalization. This gives them new properties and allows them to improve their performance for a given application. This review paper intends to understand... [more]
Controlled Preparation of Different Proportions of Metal Fe-Mn from Waste Mn Ferrite by Molten Salt Electrolysis
Shiyuan Liu, Lijun Wang
July 29, 2021 (v1)
Subject: Materials
Keywords: metallurgy, metals, molten salt electrolysis, waste Mn ferrite
A novel method for efficiently recovering Fe and Mn from waste Mn ferrite by molten salt electrolysis is firstly proposed. The electrolysis of molten salt (MnCl2 (1.06 wt%)-FeCl3 (2.69 wt%)-NaCl-KCl) was performed at 800 °C. The phase of product at 2.0 V was metal Fe while metal Fe and Mn were obtained by molten salt electrolysis at 2.3 V. The Fe/Mn mass ratio of electrodeposited products at 2.0 V and 2.3 V were 687 and 3.2, respectively. The different proportions of metal Fe-Mn were prepared by controlling the electrolytic voltages. This new method can realize direct transformation of waste Mn ferrite to Fe-Mn alloy.
Hydrophobic and Anti-Icing Behavior of UV-Laser-Treated Polyester Resin-Based Gelcoats
Rafał Kozera, Bartłomiej Przybyszewski, Zuzanna D. Krawczyk, Anna Boczkowska, Bogna Sztorch, Robert E. Przekop, Robert Barbucha, Mateusz Tański, Xabier Garcia-Casas, Ana Borras
July 28, 2021 (v1)
Subject: Materials
Keywords: freezing delay time, hydrophobicity, ice adhesion, icephobicity, laser texturization, polyhedral oligomeric, silsesquioxane, unsaturated polyester resin
Ice accumulation on wind turbine blades due to the impact of supercooled water droplets can be reduced by the application of surfaces with anti-icing properties. Hydrophobic surfaces are considered as a promising solution because of their water repellent behavior. In recent years, short-pulsed laser technologies have been developed as an efficient technique to modify the surface properties of materials. However, the anti-icing properties of such surfaces have not yet been validated. In this work, a hybrid modification of polyester resin-based gelcoats was adopted. Laser patterning (LP) was used to produce periodic surface structures on modified unsaturated polyester resin (UPR) substrates. One of the innovations of this research is the utilization of novel purpose-made chemical modifiers for gelcoats. The implementation of linear polymethylhydrosiloxane (PMHS) as a building block is a key improvement in terms of durability and functionality of the coating, since there is an option of i... [more]
Hybrid Modification of Unsaturated Polyester Resins to Obtain Hydro- and Icephobic Properties
Rafał Kozera, Bartłomiej Przybyszewski, Katarzyna Żołyńska, Anna Boczkowska, Bogna Sztorch, Robert E. Przekop
July 26, 2021 (v1)
Subject: Materials
Keywords: hydrophobicity, ice adhesion, icephobicity, multi-functionalized silicone compounds (MFSC), nanosilica, unsaturated polyester resin
Ice accumulation is a key and unsolved problem for many composite structures with polymer matrices, e.g., wind turbines and airplanes. One of the solutions to avoid icing is to use anti-icing coatings. In recent years, the influence of hydrophobicity of a surface on its icephobic properties has been studied. This solution is based on the idea that a material with poor wettability maximally reduces the contact time between a cooled drop of water and the surface, consequently prevents the formation of ice, and decreases its adhesion to the surface. In this work, a hybrid modification of a gelcoat based on unsaturated polyester resin with nanosilica and chemical modifiers from the group of triple functionalized polyhedral oligomeric silsesquioxanes (POSS) and double organofunctionalized polysiloxanes (generally called multi-functionalized organosilicon compounds (MFSC)) was applied. The work describes how the change of modifier concentration and its structural structure finally influences... [more]
In Situ Deposition of Green Silver Nanoparticles on Urinary Catheters under Photo-Irradiation for Antibacterial Properties
Fueangfahkan Chutrakulwong, Kheamrutai Thamaphat, Sukon Tantipaibulvut, Pichet Limsuwan
July 26, 2021 (v1)
Subject: Materials
Keywords: antimicrobial urinary catheter, catheter-associated urinary tract infection, durian rind, green synthesis, silver nanoparticle
Urinary tract infections, especially catheter-associated urinary tract infections (CAUTIs), are the most common type of nosocomial infections. Patients with chronic indwelling urinary catheters have a higher risk of infection due to biofilm formation on the urinary catheter surface. Therefore, in this work, a novel, cost-effective antimicrobial urinary catheter was developed using green technology. Silver nanoparticles (AgNPs) synthesized from Mon Thong durian rind waste were used as an antimicrobial agent for the prevention of infection. Flavonoids, phenolic compounds, and glucose extracted from durian rind were used as a reducing agent to reduce the Ag+ dissolved in AgNO3 solution to form non-aggregated AgNPs under light irradiation. The AgNPs were simultaneously synthesized and coated on the inner and outer surfaces of silicone indwelling urinary catheters using the dip coating method. The results showed that the antimicrobial urinary catheter fabricated using a 0.3 mM AgNO3 concent... [more]
Shear-Thinning Effect of the Spinning Disc Mixer on Starch Nanoparticle Precipitation
Sahr Sana, Vladimir Zivkovic, Kamelia Boodhoo
July 19, 2021 (v1)
Subject: Materials
Keywords: Process Intensification, shear rate, solvent–antisolvent precipitation, spinning disc, starch nanoparticles, thin films
Spinning disc technology is capable of achieving intensified micromixing within thin liquid films created through large shear rates, typically of the order of 103 s−1, generated by means of fast disc surface rotation. In this study the effect of the high shear on solvent−antisolvent mixing and starch nanoparticle precipitation is reported. Rheological studies of starch solutions at 2% w/v and 4% w/v have demonstrated their shear-thinning behaviour at the large shear rates experienced on the spinning disc surface. The effect of such high shear rate on starch nanoparticle precipitation is investigated alongside solute concentration and several other operating parameters such as flow rate, disc rotational speed, and solvent/antisolvent ratio. A reduction in nanoparticle size has been observed with an increase in starch concentration, although agglomeration was found to be more prevalent amongst these smaller particles particularly at larger flow rates and disc rotational speeds. Micromixi... [more]
Design and Fabrication of Partially Foamed Grid Structure Using Additive Manufacturing and Solid State Foaming
Byung Kyu Park, Charn-Jung Kim, Dong Eui Kwon, Youn-Woo Lee
July 12, 2021 (v1)
Subject: Materials
Keywords: 3D structure, additive manufacturing, copolymer, gradient foam, solid state foaming
A partially foamed lattice structure based on synthetic polymers was considered as a functionally graded materials due to their unique properties. In this study, a copolymer is manufactured to be porous functional materials by physical foaming technology, using carbon dioxide. Through morphological characterization, using scanning electron microscope, we identified a potential to fabricate partially foamed structures with micropores. We showed that variation of post-foaming temperature can tune the pore size distribution in the range of 0.9 to 30 μm. Thermal data of the foam grid from differential scanning calorimeter showed some shifts in glass transition, cold crystallization, and melting points. Mechanical strength and thermal conductivity were also measured to find rationale of thermal insulation with tunable mechanical strength and to elucidate the actual 3D lattice foam of a copolymer.
Biosorption: A Review of the Latest Advances
Enrique Torres
June 29, 2021 (v1)
Subject: Materials
Keywords: bioaccumulation, biocomposite, Biomass, biosorption, dyes, emerging organic contaminants, metals, pollutants
Biosorption is a variant of sorption techniques in which the sorbent is a material of biological origin. This technique is considered to be low cost and environmentally friendly, and it can be used to remove pollutants from aqueous solutions. The objective of this review is to report on the most significant recent works and most recent advances that have occurred in the last couple of years (2019−2020) in the field of biosorption. Biosorption of metals and organic compounds (dyes, antibiotics and other emerging contaminants) is considered in this review. In addition, the use and possibilities of different forms of biomass (live or dead, modified or immobilized) are also considered.
Martensitic Transformation, Thermal Analysis and Magnetocaloric Properties of Ni-Mn-Sn-Pd Alloys
Asma Wederni, Mihail Ipatov, Eloi Pineda, Lluisa Escoda, Julian-Maria González, Mohamed Khitouni, Joan-Josep Suñol
June 29, 2021 (v1)
Subject: Materials
Keywords: entropic change, Heusler alloys, magneto-structural transition, magnetocaloric effect, martensitic transition
Martensitic transition and magnetic response of Ni50−x Pdx,y Mn36 Sn14−y (x = 0, 1, 2 and y = 0, 1) Heusler alloys were analysed. The crystalline structure of each composition was solved by X-ray diffraction pattern fitting. For x = 1 and 2, the L21 austenite structure is formed and, for y = 1, the crystallographic phase is a modulated martensitic structure. From differential scanning calorimetry scans, we determine characteristic transformation temperatures and the entropy/enthalpy changes. The temperatures of the structural transformation increase with the addition of Pd to replace Ni or Sn, whereas the austenitic Curie temperature remains almost unvarying. In addition, the magneto-structural transition, investigated by magnetic measurements, is adjusted by suitable Pd doping in the alloys. The peak value of the magnetic entropy changes reached 4.5 J/(kg K) for Ni50Mn36Sn13Pd1 (external field: 50 kOe).
Gas Turbine Intercoolers: Introducing Nanofluids—A Mini-Review
Ali Alsayegh, Naser Ali
June 29, 2021 (v1)
Subject: Materials
Keywords: heat exchanger, stability, suspension, thermophysical properties, working fluid
Coolant is one of the main factors affecting the overall thermal performance of the intercooler for the gas turbine intercooled cycle. The thermal conductivity of conventional coolants, such as water, is relatively low when compared to solid conducting materials, and therefore can hinder the progress towards achieving a compact and highly effective intercooler. Nanofluids are advanced types of working fluids that contain dispersed nanoparticles in conventional basefluids, and as such possess superior thermal conductivity compared to their counterparts. In this paper, a short review on the effect of different nanofluids on the thermal performance of gas turbines intercoolers is presented for the first time. Firstly, this work reviews the different designs of intercoolers used in gas turbines intercooled cycles. Then, it explains the different types of nanofluids and their fabrication processes. The effective parameters, such as physical stability, thermal conductivity, and viscosity are... [more]
Improving Ammonium Sorption of Bayah Natural Zeolites by Hydrothermal Method
Teguh Kurniawan, Saiful Bahri, Anita Diyanah, Natasya D. Milenia, Nuryoto Nuryoto, Kajornsak Faungnawakij, Sutarat Thongratkaew, Muhammad Roil Bilad, Nurul Huda
June 29, 2021 (v1)
Subject: Materials
Keywords: Adsorption, clinoptilolite, crystallinity, Freundlich, intraparticle, ion-exchange, isotherm, kinetic, mordenite, surface area
Natural zeolites are easily found and abundant in Indonesia. The natural zeolites are low-cost minerals; however, their ammonium sorption is poor. A hydrothermal method was applied to improve the ammonium sorption. Hydrothermal treatment times were varied 8, 24, and 32 h. The parent and hydrothermal treated samples were characterized by using X-ray diffraction (XRD), Field Emission Scanning Electron Microscopes (FE-SEM), Fourier-transform infrared spectroscopy (FTIR), and nitrogen physisorption. Ammonium adsorption was performed using a batch reactor to evaluate the adsorption performance of the prepared zeolite samples. The 8 h hydrothermal (HT 8 h) treated zeolites showed the highest ammonium removal percentage among others. The XRD analysis of HT 8 h shows a higher crystallinity of mordenite and the Brunauer−Emmett−Teller (BET) model shows a surface area of 105 m2/g, much larger as compared to the parent with a surface area of 19 m2/g. Various kinetic and isotherms models were also... [more]
Heavy Metal Sorption by Sludge-Derived Biochar with Focus on Pb2+ Sorption Capacity at μg/L Concentrations
Ida Sylwan, Hanna Runtti, Lena Johansson Westholm, Henrik Romar, Eva Thorin
June 21, 2021 (v1)
Subject: Materials
Keywords: adsorbent, biosorbent, heavy metals, isotherm models, municipal wastewater, sewage treatment
Municipal wastewater management causes metal exposure to humans and the environment. Targeted metal removal is suggested to reduce metal loads during sludge reuse and release of effluent to receiving waters. Biochar is considered a low-cost sorbent with high sorption capacity for heavy metals. In this study, heavy metal sorption to sludge-derived biochar (SDBC) was investigated through batch experiments and modeling and compared to that of wood-derived biochar (WDBC) and activated carbon (AC). The aim was to investigate the sorption efficiency at metal concentrations comparable to those in municipal wastewater (<1 mg/L), for which experimental data are lacking and isotherm models have not been verified in previous works. Pb2+ removal of up to 83% was demonstrated at concentrations comparable to those in municipal wastewater, at pH 2. SDBC showed superior Pb2+ sorption capacity (maximum ~2 mg/g at pH 2) compared to WDBC and AC (<0 and (3.5 ± 0.4) × 10−3 mg/g, respectively); howeve... [more]
Showing records 1 to 25 of 475. [First] Page: 1 2 3 4 5 Last
[Show All Subjects]