Search results for: material particles

Authors: Prateek Singh, Arun Kumar Pandey, C. Raghu Kumar, M. R. Rath, A. S. Reddy

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Drum scrubber is widely used equipment in the washing of Iron ore. The purpose of the scrubber is to release the adhered fine clayey particles from the iron-bearing particles. Presently, the iron ore wash plants in the Eastern region of India consist of the scrubber, double deck screen followed by screw classifier as the main unit operations. Hence, scrubber performance efficiency has a huge impact on the downstream product quality. This paper illustrates the effect of scrubber feed % solids on scrubber performance and alumina distribution on downstream equipment. Further, it was established that scrubber performance efficiency could be defined as the ratio of the adhered particles (-0.15mm) released from scrubber feed during scrubbing operation with respect to the maximum possible release of -0.15mm (%) particles.

Keywords: scrubber, adhered particles, feed % solids, efficiency

Procedia PDF Downloads 139

Authors: Elżbieta Cygan, Bączek, Piotr Wyżga

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This paper presents the results of research on the physical, mechanical, and tribological properties of materials constituting the matrix in sintered metallic-diamond tools. The ground powders based on the Fe-Mn-Cu-Sn-C system were modified with micro-sized particles of the ceramic phase: SiC, Al₂O₃ and consolidated using the SPS (spark plasma sintering) method to a relative density of over 98% at 850-950°C, at a pressure of 35 MPa and time 10 min. After sintering, an analysis of the microstructure was conducted using scanning electron microscopy. The resulting materials were tested for the apparent density determined by Archimedes’ method, Rockwell hardness (scale B), Young’s modulus, as well as for technological properties. The performance results of obtained diamond composites were compared with the base material (Fe–Mn–Cu–Sn–C) and the commercial alloy Co-20% WC. The hardness of composites has achieved the maximum at a temperature of 900°C; therefore, it should be considered that at this temperature it was obtained optimal physical and mechanical properties of the subjects' composites were. Research on tribological properties showed that the composites modified with micro-sized particles of the ceramic phase are characterized by more than twice higher wear resistance in comparison with base materials and the commercial alloy Co-20% WC. Composites containing Al₂O₃ phase particles in the matrix material were composites containing Al₂O₃ phase particles in the matrix material were characterized by the lowest abrasion wear resistance. The manufacturing technology presented in the paper is economically justified and can be successfully used in the production process of the matrix in sintered diamond-impregnated tools used for the machining of an industrial floor system. Acknowledgment: The study was performed under LIDER IX Research Project No. LIDER/22/0085/L-9/17/NCBR/2018 entitled “Innovative metal-diamond tools without the addition of critical raw materials for applications in the process of grinding industrial floor systems” funded by the National Centre for Research and Development of Poland, Warsaw.

Keywords: abrasive wear resistance, metal matrix composites, sintered diamond tools, Spark Plasma Sintering

Procedia PDF Downloads 77

Authors: Štěpán Hýsek, Petra Gajdačová, Milan Podlena

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Annual plants are becoming more and more popular source of lignin and cellulose. In those days a lot of research is carried out in order to evaluate the possibility of utilization of fibres and particles from these plants in composite materials production. These lingo-cellulosic materials seem to be a great alternative to wood, however, due to waxy and silica layers on the surface of these stalks, one additional technological step is needed–erosion of the layers for the purpose of achieving better adhesion between particle and adhesive. In this research, we used several kinds of particle pre-treatment, in order to modify surface properties of these particles. Further, an adhesive was applied to the particles using laboratory blender and board were produced using laboratory press. Both physical and mechanical properties of boards were observed. It was found out that the surface modification of particles had statistically significant effect on properties of produced boards.

Keywords: annual plant, composites, mechanical properties, particleboard

Procedia PDF Downloads 198

Authors: M. M. Morgham, A. A. Hameda, N. A. Zriba, H. A. Jawan

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This paper aims to study the effect of cold work condition on the microstructure of Cu-1.5wt%Ti, and Cu-3.5wt%Ti and hence mechanical properties. The samples under investigation were machined and solution heat treated. X-ray diffraction technique is used to identify the different phases present after cold deformation by compression and also different heat treatment and also measuring the relative quantities of phases present. Metallographic examination is used to study the microstructure of the samples. The hardness measurements were used to indicate the change in mechanical properties. The results are compared with the mechanical properties obtained by previous workers. Experiments on cold compression followed by aging of Cu-Ti alloys have indicated that the most effective hardening of the material results from continuous precipitation of very fine particles within the matrix. These particles were reported to be β`-type, Cu4Ti phase. The β`-β transformation and particles coarsening within the matrix as well as a long grain boundaries were responsible for the averaging of Cu-1.5wt%Ti and Cu-3.5wt%Ti alloys. It is well know that plate like particles are β – type, Cu3Ti phase. Discontinuous precipitation was found to start at the grain boundaries and expand into grain interior. At the higher aging temperature a classic widmanstätten morphology forms giving rise to a coarse microstructure comprised of α and the equilibrium phase β. Those results were confirmed by X-ray analysis, which found that a few percent of Cu3Ti, β precipitates are formed during aging at high temperature for long time for both Cu- Ti alloys (i.e. Cu-1.5wt%Ti and Cu-3.5wt%Ti).

Keywords: metallographic, hardness, precipitation, aging

Procedia PDF Downloads 406

Authors: Miroslav Mrlik, Marketa Ilcikova, Martin Cvek, Josef Osicka, Michal Sedlacik, Vladimir Pavlinek, Jaroslav Mosnacek

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Magnetorheological elastomers (MREs) are a unique type of materials consisting of two components, magnetic filler, and elastomeric matrix. Their properties can be tailored upon application of an external magnetic field strength. In this case, the change of the viscoelastic properties (viscoelastic moduli, complex viscosity) are influenced by two crucial factors. The first one is magnetic performance of the particles and the second one is off-state stiffness of the elastomeric matrix. The former factor strongly depends on the intended applications; however general rule is that higher magnetic performance of the particles provides higher MR performance of the MRE. Since magnetic particles possess low stability properties against temperature and acidic environment, several methods how to improve these drawbacks have been developed. In the most cases, the preparation of the core-shell structures was employed as a suitable method for preservation of the magnetic particles against thermal and chemical oxidations. However, if the shell material is not single-layer substance, but polymer material, the magnetic performance is significantly suppressed, due to the in situ polymerization technique, when it is very difficult to control the polymerization rate and the polymer shell is too thick. The second factor is the off-state stiffness of the elastomeric matrix. Since the MR effectivity is calculated as the relative value of the elastic modulus upon magnetic field application divided by elastic modulus in the absence of the external field, also the tuneability of the cross-linking reaction is highly desired. Therefore, this study is focused on the controllable modification of magnetic particles using a novel monomeric system based on 2-(1H-pyrrol-1-yl)ethyl methacrylate. In this case, the short polymer chains of different chain lengths and low polydispersity index will be prepared, and thus tailorable stability properties can be achieved. Since the relatively thin polymer chains will be grafted on the surface of magnetic particles, their magnetic performance will be affected only slightly. Furthermore, also the cross-linking density will be affected, due to the presence of the short polymer chains. From the application point of view, such MREs can be utilized for, magneto-resistors, piezoresistors or pressure sensors especially, when the conducting shell on the magnetic particles will be created. Therefore, the selection of the pyrrole-based monomer is very crucial and controllably thin layer of conducting polymer can be prepared. Finally, such composite particle consisting of magnetic core and conducting shell dispersed in elastomeric matrix can find also the utilization in shielding application of electromagnetic waves.

Keywords: atom transfer radical polymerization, core-shell, particle modification, electromagnetic waves shielding

Procedia PDF Downloads 209

Authors: Shukran M. Dadayev

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To author's best knowledge, in this paper, the Basic Properties and Research methods of a Fundamental Particle is studied for the first time. That's to say, Fundamental Particle has not been discovered in the Nature yet. Because Fundamental Particle consists of specific Physical, Geometrical and Internal bases. Geometrical and Internal characteristics that are considered significant for the elementary and fundamental particles aren’t basic properties, characteristics or criteria of a Fundamental Particle. Of course, completely new Physical and Visual experimental methods of Quantum mechanics and Behavioral-Physical investigations of Particles are needed to study and discover the Fundamental Particle. These are new Physical, Visual and Behavioral-Physical experimental methods for describing and discovering the Fundamental Particle in the Nature and Microworld. Fundamental Particle consists of the same Energy-Mass-Motion system and a symmetry of Energy-Mass-Motion. Fundamental Particle supplies each of the elementary particles with the same Energy-Mass-Motion system at the same time and regulates each of the particles. Fundamental Particle gives Energy, Mass and Motion to each particles at the same time, each of the Particles consists of acquired Energy-Mass-Motion system and symmetry. Energy, Mass, Motion given by the Fundamental Particle to the particles are Symmetrical Equivalent and they remain in their primary shapes in all cases. Fundamental Particle gives Energy-Mass-Motion system and symmetry consisting of different measures and functions to each of the particles. The Motion given by the Fundamental Particle to the particles is Gravitation, Gravitational Interaction not only gives Motion, but also cause Motion by attracting. All Substances, Fields and Cosmic objects consist of Energy-Mass-Motion. The Field also includes specific Mass. They are always Energetic, Massive and Active. Fundamental Particle establishes the bases of the Nature. Supplement and Regulating of all the particles existing in the Nature belongs to Fundamental Particle.

Keywords: basic properties of a fundamental particle, behavioral-physical and visual methods, energy-mass-motion system and symmetrical equivalence, fundamental particle

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Authors: N. Demirsoy, N. Uçar, A. Önen, N. Kızıldağ, Ö. F. Vurur, O. Eren, İ. Karacan

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Polymer composite nano-fibers including (1, 3 wt %) silver nano-particles have been produced by electrospinning method. Polyacrylonitrile/N,N-dimethylformamide (PAN/DMF) solution has been prepared and the amount of silver nitrate has been adjusted to PAN weight. Silver nano-particles were obtained from reduction of silver ions into silver nano-particles by chemical reduction by hydrazine hydroxide (N2H5OH). The different amount of silver salt was loaded into polymer matrix to obtain polyacrylonitrile composite nano-fiber containing silver nano-particles. The effect of the amount of silver nano-particles on the properties of composite nano-fiber web was investigated. Electrical conductivity, mechanical properties, thermal properties were examined by Microtest LCR Meter 6370 (0.01 mΩ-100 MΩ), tensile tester, differential scanning calorimeter DSC (Q10) and SEM, respectively. Also, antimicrobial efficiency test (ASTM E2149-10) was done against Staphylococcus aureus bacteria. It has been seen that breaking strength, conductivity, antimicrobial effect, enthalpy during cyclization increase by use of silver nano-particles while the diameter of nano-fiber decreases.

Keywords: composite polyacrylonitrile nanofiber, electrical conductivity, electrospinning, mechanical properties, thermal properties, silver nanoparticles

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Authors: Javier Perez-Vaquero, Katryn Junker, Volker Lammers, Petra Foerst

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There is increasing importance to accelerate the transition to sustainable food systems by including environmentally friendly technologies. Our work focuses on protein enrichment and fractionation of agricultural side streams by dry triboelectrostatic separation technology. Materials are fed in particulate form into a system dispersed in a highly turbulent gas stream, whereby the high collision rate of particles against surfaces and other particles greatly enhances the electrostatic charge build-up over the particle surface. A subsequent step takes the charged particles to a delimited zone in the system where there is a highly uniform, intense electric field applied. Because the charge polarity acquired by a particle is influenced by its chemical composition, morphology, and structure, the protein-rich and fiber-rich particles of the starting material get opposite charge polarities, thus following different paths as they move through the region where the electric field is present. The output is two material fractions, which differ in their respective protein content. One is a fiber-rich, low-protein fraction, while the other is a high-protein, low-fiber composition. Prior to testing, materials undergo a milling process, and some samples are stored under controlled humidity conditions. In this way, the influence of both particle size and humidity content was established. We used two oilseed meals: lupine and rapeseed. In addition to a lab-scale separator to perform the experiments, the triboelectric separation process could be successfully scaled up to a mid-scale belt separator, increasing the mass feed from g/sec to kg/hour. The triboelectrostatic separation technology opens a huge potential for the exploitation of so far underutilized alternative protein sources. Agricultural side-streams from cereal and oil production, which are generated in high volumes by the industries, can further be valorized by this process.

Keywords: bench-scale processing, dry separation, protein-enrichment, triboelectrostatic separation

Procedia PDF Downloads 190

Authors: Sabriye Piskin, Sibel Kasap, Muge Sari Yilmaz

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Nanocrystalline TiO₂ particles were successfully synthesized via sol-gel and sonochemical combination using titanium tetraisopropoxide as a precursor at lower temperature for a short time. The effect of the reaction parameters (hydrolysis media, acid media, and reaction temperatures) on the synthesis of TiO₂ particles were investigated in the present study. Characterizations of synthesized samples were prepared by X-ray diffraction (XRD) analysis. It was shown that the reaction parameters played a significant role in the synthesis of TiO₂ particles.

Keywords: crystalline TiO2, sonochemical mechanism, sol-gel reaction, XRD

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Authors: Benny Alexander, Ikhlashia N. Fadhilah, Muhammad R. Pasha, Michelle Julia, Anne Z. Syahrial

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Brake shoe is a component that serves to reduce speed or stop the train's speed by utilizing the friction force. Generally, the material used as a brake shoe is cast iron, where cast iron itself is a heavy, expensive, and easily worn material. Aluminum matrix composites are one of candidates for the cast iron replacement material as the basic material for brake shoe. The matrix in the composite used is Aluminum AC4B. Reinforcement used in aluminum matrix composites is nano-alumina, where the use of nano-alumina of 0.25%, 0.3%, 0.35%, 0.4%, and 0.5% volume fraction will be tested. The sample is made using the stir casting method; then, it will be tested mechanically. The use of nano-alumina as a reinforcement will increase the strength of the matrix. SEM (scanning electron microscopy) testing is used to test the distribution of reinforcing particles due to stirring. Therefore, the addition of nano-alumina will improve AC4B aluminum matrix composites.

Keywords: aluminium matrix composites, brake shoe application, stir casting, nano-alumina

Procedia PDF Downloads 132

Authors: Sayed Hessam Bahmani, Rolsndo P. Orense

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From an engineering point of view, pumice particles are problematic because of their crushability and compressibility due to their vesicular nature. Currently, information on the geotechnical characteristics of pumice sands is limited. While extensive empirical and laboratory tests can be implemented to characterize their behavior, these are generally time-consuming and expensive. These drawbacks have motivated attempts to study the effects of particle breakage of pumice sand through the Discrete Element Method (DEM). This method provides insights into the behavior of crushable granular material at both the micro and macro-level. In this paper, the results of single-particle crushing tests conducted in the laboratory are simulated using DEM through the open-source code YADE. This is done to better understand the parameters necessary to represent the pumice microstructure that governs its crushing features, and to examine how the resulting microstructure evolution affects a particle’s properties. The DEM particle model is then used to simulate the behavior of pumice sand during consolidated drained triaxial tests. The results indicate the importance of incorporating particle porosity and unique surface textures in the material characterization and show that interlocking between the crushed particles significantly influences the drained behavior of the pumice specimen.

Keywords: pumice sand, triaxial compression, simulation, particle breakage

Procedia PDF Downloads 245

Authors: K. N. Umesh

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Wood Polymer Composites (WPC) were synthesized artificially by combining polypropylene, wood and resin. It is difficult to obtain a good surface finish by conventional machining on WPC because of material degradation due to excessive heat generated during the process. In order to preserve the material property and deliver a better surface finish and accuracy, a proper solution is devised for the machining of wood composites at low temperature. This research focuses on studying the effects of parameters of cryogenic machining on sawdust incorporated polypropylene composite material, in view of evolving the most suitable composition and an appropriate combination of process parameters. The machining characteristics of the six different compositions of WPC were evaluated by analyzing the trend. An attempt is made to determine proper combinations material composition and process control parameters, through process capability studies. A WPC of 80%-wood (saw dust particles), 20%-polypropylene and 0%-resin was found to be the best alternative for obtaining the best surface finish under cryogenic machining conditions.

Keywords: Cryogenic Machining, Process Capability, Surface Finish, Wood Polymer Composites

Procedia PDF Downloads 249

Authors: Sergei Zhevnenko

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Сontinuous layer of tantalum boride is formed on the surface as a result of reactive wetting of oxidized tantalum by copper melt with boron at a temperatures above 1150 °C. An increase in the wetting temperature above 1400 °C leads to a change in the formation mechanism of tantalum borides, they are formed in the nanosized flakes. In the presented work, we studied the process of copper-based in-situ composite formation, strengthened by the particles of tantalum borides. We investigated the structure of the formed particles, the conditions, and the kinetics of their formation. Dissolving boride particles do not have time to mix uniformly in the melt upon sufficiently rapid cooling and form a macrostructure, partly repeating the shape of the metallic tantalum. This allows to set different gradient structures in the copper alloy. Such macrostructures have been obtained. Boride particles and microstructures were studied by scanning and transmission electron microscopy, and regions with particles were investigated by nanoindentation. In this work, we also measured the kinetics of impregnation of porous tantalum with copper-boron melt and studied the structures of the composite, in which the melt filling the interpore space is saturated with boride particles.

Keywords: copper, tantalum borides, in-situ composites, wetting, imbibition

Procedia PDF Downloads 103

Authors: Endrick Barnacin, Jean-Luc Henry, Jimmy Nagau, Jack Molinie

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Being able to identify biological particles such as spores, viruses, or pollens is important for health care professionals, as it allows for appropriate therapeutic management of patients. Optical microscopy is a technology widely used for the analysis of these types of microorganisms, because, compared to other types of microscopy, it is not expensive. The analysis of an optical microscope slide is a tedious and time-consuming task when done manually. However, using machine learning and computer vision, this process can be automated. The first step of an automated microscope slide image analysis process is segmentation. During this step, the biological particles are localized and extracted. Very often, the use of an automatic thresholding method is sufficient to locate and extract the particles. However, in some cases, the particles are not extracted individually because they are stuck to other biological elements. In this paper, we propose a stuck particles separation method based on the use of the Sobel operator and thresholding. We illustrate it by applying it to the separation of 813 images of adjacent pollen grains. The method correctly separated 95.4% of these images.

Keywords: image segmentation, stuck particles separation, Sobel operator, thresholding

Procedia PDF Downloads 129

Authors: Abdulrahman Alenezi, B. Stefan

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Abstract— The investigation of fluids containing particles or filaments includes a category of complex fluids and is vital in both theory and application. The forecast of particle behaviors plays a significant role in the existing technology as well as future technology. This paper focuses on the prediction of the particle behavior through the investigation of the particle disentrainment from a pipe on a horizontal air stream. This allows for examining the influence of the particle physical properties on its behavior when falling on horizontal air stream. This investigation was conducted on a device located at the University of Greenwich's Medway Campus. Two materials were selected to carry out this study: Salt and Glass Beads particles. The shape of the Slat particles is cubic where the shape of the Glass Beads is almost spherical. The outcome from the experimental work were presented in terms of distance travelled by the particles according to their diameters as After that, the particles sizes were measured using Laser Diffraction device and used to determine the drag coefficient and the settling velocity.

Keywords: flow experiment, drag coefficient, Particle Settling, Flow Chamber

Procedia PDF Downloads 136

Authors: Harika Dasari, Eric Eisenbraun

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The present study models the role of electrode structural characteristics on the thermal behavior of lithium-ion batteries. Preliminary modeling runs have employed a 1D lithium-ion battery coupled to a two-dimensional axisymmetric model using silicon as the battery anode material. The two models are coupled by the heat generated and the average temperature. Our study is focused on the silicon anode particle sizes and it is observed that silicon anodes with nano-sized particles reduced the temperature of the battery in comparison to anodes with larger particles. These results are discussed in the context of the relationship between particle size and thermal transport properties in the electrode.

Keywords: particle size, NMC, silicon, heat generation, separator

Procedia PDF Downloads 289

Authors: Abdelkader Djehiche, Mostefa Gafsi, Henri Bertin, Aziz Omari

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The flows of colloidal suspensions in porous media find many applications in fields such as Petroleum, Hydraulic engineering, deep-bed filtration. For each application, the scientific problems can be summarized the flow in porous medium of a colloidal suspension whose particles having characteristic dimension is considerable in comparison with the pores dimension. In certain cases, one can observe a deposit of particles on the surface of the pores which results in a significant modification in the physical properties of the porous medium. The objective of our study is to use a non-destructive experimental method, the attenuation of g-rays, to study the influence of the number of Peclet on the deposit of latex particles in a consolidated porous medium. The first results obtained show a good agreement between local and global measurements of the deposit of the particles in porous medium. The deposit takes place in a progressive way along the porous medium and leads to a monolayer deposit of which the average thickness is of about the size diameter of the colloidal particles.

Keywords: colloid, gamma ray, Peclet number, permeability, porous medium

Procedia PDF Downloads 186

Authors: Bharath Kenchappa, Kunigal Shivakumar

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Lightweight, low thermal conductivity and high temperature resistant materials or the system with moderate mechanical properties and capable of taking high heating rates are needed in both commercial and military applications. A single material with these attributes is very difficult to find and one needs to come with innovative ideas to make such material system using what is available. To bring down the cost of the system, one has to be conscious about the cost of basic materials. Such a material system can be called as the thermal barrier system. This paper focuses on developing, testing and characterization of material system for thermal barrier applications. The material developed is porous, low density, low thermal conductivity of 0.1062 W/m C and glass transition temperature about 310 C. Also, the thermal properties of the developed material was measured in both longitudinal and thickness direction to highlight the fact that the material shows isotropic behavior. The material is called modified Eco-Core which uses only less than 9% weight of high-char resin in the composite. The filler (reinforcing material) is a component of fly ash called Cenosphere, they are hollow micro-bubbles made of ceramic materials. Special mixing-technique is used to surface coat the fillers with a thin layer of resin to develop a point-to-point contact of particles. One could use commercial ceramic micro-bubbles instead of Cenospheres, but it is expensive. The bulk density of Cenospheres is about 0.35 g/cc and we could accomplish the composite density of about 0.4 g/cc. One percent filler weight of 3mm length standard drywall grade fibers was used to bring the added toughness. Both thermal and mechanical characterization was performed and properties are documented. For higher temperature applications (up to 1,000 C), a hybrid system was developed using an aerogel mat. Properties of combined material was characterized and documented. Thermal tests were conducted on both the bare modified Eco-Core and hybrid materials to assess the suitability of the material to a thermal barrier application. The hybrid material system was found to meet the requirement of the application.

Keywords: aerogel, fly ash, porous material, thermal barrier

Procedia PDF Downloads 111

Authors: K. Kamburova, N. Boshkova, N. Boshkov, T. Radeva

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Coatings based on polyaniline (PANI) can improve the resistance of steel against corrosion. Two forms of PANI are generally accepted to have effective protection of steel: the conducting emeraldine salt (ES) and the non-conducting emeraldine base (EB). The ability to intercept electrons at the metal surface and to transport them is typically attributed to ES, while the success of EB as an anticorrosive additive in the coating is attributed to its ability to oxidize and reduce in a reversible way. This electrochemical mechanism is probably combined with barrier effect against corrosion species. In this work, we describe the preparation of stable suspensions of colloidal PANI-SiO₂ particles, suitable for obtaining of composite anticorrosive coating on steel. Electrokinetic data as a function of pH are presented, showing that the zeta potentials of the PANI-SiO₂ particles are governed primarily by the charged groups at the silica oxide surface. Electrosteric stabilization of the PANI-SiO₂ particles’ suspension against aggregation is realized at pH > 5.5 (EB form of PANI) by adsorption of positively charged polyelectrolyte molecules onto negatively charged PANI-SiO₂ particles. We anticipate that incorporation of the small particles will provide a more homogeneous distribution in the coating matrix and will decrease the negative effect on barrier properties of the composite coating.

Keywords: particles, stable dispersion, composite coatings, corrosion protection

Procedia PDF Downloads 175

Authors: Yang Li, Mingkai Liu, Qiong Rao, Zhongrui Gai, Ying Pan, Hongguang Jin

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Hydrogen is an ideal and potential energy carrier due to its high energy efficiency and low pollution. An alternative and promising approach to hydrogen generation is the chemical looping steam reforming of methane (CL-SRM) over iron-based oxygen carriers. However, the process faces challenges such as high reaction temperature (>850 ℃) and low methane conversion. We demonstrate that Ni-mixed Fe-based oxygen carrier particles have significantly improved the methane conversion and hydrogen production rate in the range of 450-600 ℃ under atmospheric pressure. The effect on the reaction reactivity of oxygen carrier particles mixed with different Ni-based particle mass ratios has been determined in the continuous unit. More than 85% of methane conversion has been achieved at 600 ℃, and hydrogen can be produced in both reduction and oxidation steps. Moreover, the iron-based oxygen carrier particles exhibited good cyclic performance during 150 consecutive redox cycles at 600 ℃. The mid-temperature iron-based oxygen carrier particles, integrated with a moving-bed chemical looping system, might provide a powerful approach toward more efficient and scalable hydrogen production.

Keywords: chemical looping, hydrogen production, mid-temperature, oxygen carrier particles

Procedia PDF Downloads 142

Authors: Anjela Koblischka-Veneva, Michael Koblischka

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In this contribution, the transmission-Kikuchi diffrac-tion (TKD, or sometimes called t-EBSD) is applied to bulk, melt-grown YBa2Cu3O7 (YBCO) superconductors prepared by the MTMG (melt-textured melt-grown) technique and the infiltration (IG) growth technique. TEM slices required for the analysis were prepared by means of focused ion-beam (FIB) milling using mechanically polished sample surfaces, which enable a proper selection of the in-teresting regions for investigations. The required optical transparency was reached by an additional polishing step of the resulting surfaces using FIB-Ga-ion and Ar-ion milling. The improved spatial resolution of TKD enabled the investigation of the tiny Y2BaCuO5 (Y-211) particles having a diameter of about 50-100 nm embedded within the YBCO matrix and of other added secondary phase particles. With the TKD technique, the microstructural properties of the YBCO matrix are studied in detail. It is observed that the matrix shows effects of stress/strain, depending on the size and distribution of the embedded particles, which are important for providing additional flux pinning centers in such superconducting bulk samples. Using the Kernel average misorientation (KAM) maps, the strain induced in the superconducting matrix around the particles, which increases the flux pinning effectivity, can be clearly revealed. This type of analysis of the EBSD/TKD data is, therefore, also important for other material systems, where nanoparticles are embedded in a matrix.

Keywords: electron backscatter Diffraction, transmission Kikuchi diffraction, SEM, YBCO, microstructure, nanoparticles

Procedia PDF Downloads 128

Authors: Navid Zanganeh, Hafez Balavi, Farbod Sharif, Mahla Zabet, Marzieh Bakhtiary Noodeh

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Cerium oxide (CeO2) also known as cerium dioxide or ceria is a pale yellow-white powder with various applications in the industry from wood coating to cosmetics, filtration, fuel cell electrolytes, gas sensors, hybrid solar cells and catalysts. In this research, attempts were made to synthesize and characterization of CeO2 nano-particles via sol-gel method. In addition, the effect of aging time on the size of particles was investigated. For this purpose, the aging times adjusted 48, 56, 64, and 72 min. The obtained particles were characterized by x-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), transmitted electron microscopy (TEM), and Brunauer–Emmett–Teller (BET). As a result, XRD patterns confirmed the formation of CeO2 nanoparticles. SEM and TEM images illustrated the nano-particles with cluster shape, spherical and a nano-size range which was in agreement with XRD results. The finest particles (7.3 nm) was obtained at the optimum condition which was aging time of 48 min, calcination temperature at 400 ⁰C, and cerium concentration of 0.004 mol. Average specific surface area of the particles at optimum condition was measured by BET analysis and recorded as 47.57 m2/g.

Keywords: aging time, CeO2 nanoparticles, size distribution, sol-gel

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Authors: Daniel Karthik, Vijay Baheti, Jiri Militky, Sundaramurthy Palanisamy

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Fibre based nano particles are presently considered as one of the potential filler materials for the improvement of mechanical and physical properties of polymer composites. Due to high matrix-filler interfacial area there will be uniform and homogeneous dispersion of nanoparticles. In micro/nano filler reinforced composites, resin material is usually tailored by organic or inorganic nanoparticles to have improved matrix properties. The objective of this study was to compare the potential of reinforcement of different organic and inorganic micro/nano fillers in epoxy composites. Industrial and agricultural waste of fibres like Agave Americana, cornhusk, jute, basalt, carbon, glass and fly ash was utilized to prepare micro/nano particles. Micro/nano particles were obtained using high energy planetary ball milling process in dry condition. Milling time and ball size were kept constant throughout the ball milling process. Composites were fabricated by hand lay method. Particle loading was kept constant to 3% wt. for all composites. In present study, loading of fillers was selected as 3 wt. % for all composites. Dynamic mechanical properties of the nanocomposite films were performed in three-point bending mode with gauge length and sample width of 50 mm and 10 mm respectively. The samples were subjected to an oscillating frequency of 1 Hz, 5 Hz and 10 Hz and 100 % oscillating amplitude in the temperature ranges of 30°C to 150°C at the heating rate of 3°C/min. Damping was found to be higher with the jute composites. Amongst organic fillers lowest damping factor was observed with Agave Americana particles, this means that Agave americana fibre particles have betters interface adhesion with epoxy resin. Basalt, fly ash and glass particles have almost similar damping factors confirming better interface adhesion with epoxy.

Keywords: ball milling, damping factor, matrix-filler interface, particle reinforcements

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Authors: Mohammad Reza Koushki Ardestani, Saeed Daneshmand, Mohammad Heydari Vini

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In the present study, AA7075/SiO2 composites have been fabricated via liquid metallurgy process. Using the degassing process, the wet ability of the molten aluminum alloys increased which improved the bonding between aluminum matrix and reinforcement (SiO2) particles. AA7075 alloy and SiO2 particles were taken as the base matrix and reinforcements, respectively. Then, contents of 2.5 and 5 wt. % of SiO2 subdivisions were added into the AA7075 matrix. To improve wettability and distribution, reinforcement particles were pre-heated to a temperature of 550°C for each composite sample. A uniform distribution of SiO2 particles was observed through the matrix alloy in the microstructural study. A hardened EN32 steel disc as the counter face was used to evaluate the wear rate pin-on-disc, a wear testing machine containing. The results showed that the wear rate of the AA/SiO2 composites was lesser than that of the monolithic AA7075 samples. Finally, The SEM worn surfaces of samples were investigated.

Keywords: Al7075, SiO₂, wear, composites, stir casting

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Authors: Amin Akhnoukh, Halla Elea, Lawrence Benzmiller

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The objective of this research is to evaluate the possibility of using nano-sized materials, mainly titanium dioxide (TiO2), in producing economic self-cleaning concrete using photo-catalysis process. In photo-catalysis, the nano-particles react and dissolve smog, dust, and dirt particles in the presence of sunlight, resulting in a cleaned concrete surface. To-date, the Italian cement company (Italcementi) produces a proprietary self-cleaning cementitious material that is currently used in government buildings and major highways in Europe. The high initial cost of the proprietary product represents a major obstacle to the wide spread of the self-cleaning concrete in industrial and commercial projects. In this research project, titanium dioxide nano-sized particles are infused to the top layer of a concrete pour before the concrete surface is finished. Once hardened, a blue dye is applied to the concrete surface to simulate smog and dirt effect. The concrete surface is subjected to direct light to investigate the effectiveness of the nano-sized titanium dioxide in cleaning the concrete surface. The outcome of this research project proved that the titanium dioxide can be successfully used in reducing smog and dirt particles attached to the concrete when infused to the surface concrete layer. The majority of cleansing effect due to photocatalysis happens within 24 hours of photocatalysis process. The non-proprietary mix can be used in highway, industrial, and commercial projects due to its economy and ease of production.

Keywords: self-cleaning concrete, photocatalysis, Smog-eating concrete, titanium dioxide

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Authors: S. M. Chabane sari S. Zargou, A.R. Senoudi, F. Benmouna

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Immobilization of nano particles (NPs) is the subject of numerous studies pertaining to the design of polymer nano composites, supported catalysts, bioactive colloidal crystals, inverse opals for novel optical materials, latex templated-hollow inorganic capsules, immunodiagnostic assays; “Pickering” emulsion polymerization for making latex particles and film-forming composites or Janus particles; chemo- and biosensors, tunable plasmonic nano structures, hybrid porous monoliths for separation science and technology, biocidal polymer/metal nano particle composite coatings, and so on. Particularly, in the recent years, the literature has witnessed an impressive progress of investigations on polymer coatings, grafts and particles as supports for anchoring nano particles. This is actually due to several factors: polymer chains are flexible and may contain a variety of functional groups that are able to efficiently immobilize nano particles and their precursors by dispersive or van der Waals, electrostatic, hydrogen or covalent bonds. We review methods to prepare polymer-immobilized nano particles through a plethora of strategies in view of developing systems for separation, sensing, extraction and catalysis. The emphasis is on methods to provide (i) polymer brushes and grafts; (ii) monoliths and porous polymer systems; (iii) natural polymers and (iv) conjugated polymers as platforms for anchoring nano particles. The latter range from soft bio macromolecular species (proteins, DNA) to metallic, C60, semiconductor and oxide nano particles; they can be attached through electrostatic interactions or covalent bonding. It is very clear that physicochemical properties of polymers (e.g. sensing and separation) are enhanced by anchored nano particles, while polymers provide excellent platforms for dispersing nano particles for e.g. high catalytic performances. We thus anticipate that the synergetic role of polymeric supports and anchored particles will increasingly be exploited in view of designing unique hybrid systems with unprecedented properties.

Keywords: gold, layer, polymer, macromolecular

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Authors: Luristya Nur Mahfut, Nada Mawarda Rilek, Ameiga Cautsarina Putri, Mujaroh Khotimah

Abstract:

The use of bioetanol from lignocellulosic material has begone to be developed. In Indonesia the most abundant lignocellulosic material is stem of palm which contain 32.22% of cellulose. Indonesia produces approximatelly 300.375.000 tons of stem of palm each year. To produce bioetanol from lignocellulosic material, the first process is pretreatment. But, until now the method of lignocellulosic pretretament is uneffective. This is related to the particle size and the method of pretreatment of less than optimal so that led to an overhaul of the lignin insufficient, consequently increased levels of cellulose was not significant resulting in low yield of bioetanol. To solve the problem, this research was implemented by using the process of pretreatment method ultasonifikasi in order to produce higher pulp with nano-sized particles that will obtain higher of yield ethanol from stem of palm. Research methods used in this research is the RAK that is composed of one factor which is the frequency ultrasonic waves with three varians, they are 30 kHz, 40 kHz, 50 kHz, and use constant variable is concentration of NaOH. The analysis conducted in this research is the influence of the frequency of the wave to increase levels of cellulose and change size on the scale of nanometers on pretreatment process by using the PSA methods (Particle Size Analyzer), and a Cheason. For the analysis of the results, data, and best treatment using ANOVA and test BNT with confidence interval 5%. The best treatment was obtained by combination X3 (frequency of sonication 50 kHz) and lignin (19,6%) cellulose (59,49%) and hemicellulose (11,8%) with particle size 385,2nm (18,8%).

Keywords: bioethanol, pretreatment, stem of palm, cellulosa

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Authors: Eda Gök

Abstract:

Peridynamics is a new modeling concept of non-local interactions for solid structures. The formulations of Peridynamic (PD) theory are based on integral equations rather than differential equations. Through, undefined equations of associated problems are avoided. PD theory might be defined as continuum version of molecular dynamics. The medium is usually modeled with mass particles bonded together. Particles interact with each other directly across finite distances through central forces named as bonds. The main assumption of this theory is that the body is composed of material points which interact with other material points within a finite distance. Although, PD theory developed for discontinuities, it gives good results for structures which have no discontinuities. In this paper, displacement control of the isotropic plate under the effect of tensile and bending loading has been investigated by means of PD theory. A MATLAB code is generated to create PD bonds and corresponding surface correction factors. Using generated MATLAB code the geometry of the specimen is generated, and the code is implemented in Finite Element Software. The results obtained from non-local continuum theory are compared with the Finite Element Analysis results and analytical solution. The results show good agreement.

Keywords: non-local continuum mechanics, peridynamic theory, solid structures, tensile loading, flexural loading

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Authors: Hammad Aziz

Abstract:

Intumescent fire retardant coating (IFRC) is applied on the surface of material requiring fire protection. In this research work, IFRC’s were developed using ammonium polyphosphate, expandable graphite, melamine, boric acid, zinc borate, mica, magnesium oxide, and bisphenol A BE-188 with polyamide polyamine H-4014 as curing agent. Formulations were prepared using nano size MgO and compared with control formulation i.e. without nano size MgO. Small scale hydrocarbon fire test was conducted to scrutinize the thermal performance of the coating. Char and coating were further characterized by using FESEM, FTIR, EDS, TGA and DTGA. Thus, Intumescent coatings reinforced with 2 wt. % of nano-MgO (rod shaped particles) provide superior thermal performance and uniform microstructure of char due to well dispersion of nano particles.

Keywords: intumescent coating, char, SEM, TGA

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Authors: Erin M. Durke, Monica L. McEntee, Meilu He, Suresh Dhaniyala

Abstract:

Aerosols are one of the most important and significant surfaces in the atmosphere. They can influence weather, absorption, and reflection of light, and reactivity of atmospheric constituents. A notable feature of aerosol particles is the presence of a surface charge, a characteristic imparted via the aerosolization process. The existence of charge can complicate the interrogation of aerosol particles, so many researchers remove or neutralize aerosol particles before characterization. However, the charge is present in real-world samples, and likely has an effect on the physical and chemical properties of an aerosolized material. In our studies, we aerosolized different materials in an attempt to characterize the charge imparted via the aerosolization process and determine what impact it has on the aerosolized materials’ properties. The metal oxides, TiO₂ and SiO₂, were aerosolized expulsively and then characterized, using several different techniques, in an effort to determine the surface charge imparted upon the particles via the aerosolization process. Particle charge distribution measurements were conducted via the employment of a custom scanning mobility particle sizer. The results of the charge distribution measurements indicated that expulsive generation of 0.2 µm SiO₂ particles produced aerosols with upwards of 30+ charges on the surface of the particle. Determination of the degree of surface charging led to the use of non-traditional techniques to explore the impact of additional surface charge on the overall reactivity of the metal oxides, specifically TiO₂. TiO₂ was aerosolized, again expulsively, onto a gold-coated tungsten mesh, which was then evaluated with transmission infrared spectroscopy in an ultra-high vacuum environment. The TiO₂ aerosols were exposed to O₂, H₂, and CO, respectively. Exposure to O₂ resulted in a decrease in the overall baseline of the aerosol spectrum, suggesting O₂ removed some of the surface charge imparted during aerosolization. Upon exposure to H₂, there was no observable rise in the baseline of the IR spectrum, as is typically seen for TiO₂, due to the population of electrons into the shallow trapped states and subsequent promotion of the electrons into the conduction band. This result suggests that the additional charge imparted via aerosolization fills the trapped states, therefore no rise is seen upon exposure to H₂. Dosing the TiO₂ aerosols with CO showed no adsorption of CO on the surface, even at lower temperatures (~100 K), indicating the additional charge on the aerosol surface prevents the CO molecules from adsorbing to the TiO₂ surface. The results observed during exposure suggest that the additional charge imparted via aerosolization impacts the interaction with each probe gas.

Keywords: aerosols, charge, reactivity, infrared

Procedia PDF Downloads 123