Papers by Keyword: Particle

Abstract: The use of out-of-furnace desulphurization of cast iron and various dispersed desulfurizing reagents is due to the desire to ensure the most complete removal of cast iron sulfur in the shortest period of time. The actual results of the industrial application of out-of-furnace desulfurization indicate that the practical results and application rates in a number of cases are not stable enough and are far from possible and expected. The studies were carried out on calculated and "cold" transparent physical models. Magnesium, lime, and calcium carbide were evaluated as desulfurizing reagents. Based on the actual results of physical modeling and subsequent calculations, an improved expression was formulated for determining the length of a gas jet in a liquid (L_str ) - the depth of the jet immersion, depending on the parameters of injection through a submerged lance. The processes of interaction between gas and solid phases in the near-lance zone during ladle desulphurization have been studied. It is shown that during the injection desulfurization of cast iron, the gas component of the flow stops its directional movement in the melt for up to 80 mm (practically 50–60 mm), solid particles continue to move in the bubble and hit the surface of this cavity. To assess the further movement of the particle through the "gas cavity-melt" boundary, the depth of penetration of particles into liquid iron was calculated. The motion of a particle in a melt can be described by an equation that is arranged for the conditions of vertical motion of a particle from top to bottom with a given initial velocity up to the complete stop of the particle. Nomograms are given to determine the specified parameters. Recommendations are given on the parameters of injection of magnesium and ground lime.

Abstract: Silica-coating is one of simple methods to colloidally stabilize particles. The present work proposed a method for fabricating silica-coated ruby particles having a particle size of ca. 1 µm (ruby/SiO₂) by a process based on a Stöber method. Two systems were examined, which were the systems using sodium hydroxide (NaOH) and aqueous ammonia (NH₄OH) as base catalysts for a sol-gel reaction. In the NaOH system, not only the ruby/SiO₂ particles with silica shells with a thickness of ca. 61 nm but also core-free SiO₂ particles were produced by adding tetraethyl orthosilicate/ethanol solution and NaOH aqueous solution to ethanol dispersing the ruby particle powder. In the NH₄OH system, it was demonstrated that it was possible to increase the shell thickness to 132 nm by repeating addition of TEOS and NH₄OH to a mixture of ruby particles, water, and ethanol, which meant that it was found to vary the shell thickness. The ruby particles emitted luminescence even after the silica-coating, which found that the silica-coating did not deteriorate luminescence property of ruby particles.

Abstract: The front opening unified pod (FOUP) is a packing box for contamination control for semiconductor wafer transport. As the wafer fabrication process developes towards nanoor atom level, the semiconductor wafer storage device should advance from the particle prevention function into the airborne molecular contamination (AMC) removal function. Therefore, it is necessary to design/redesign a function for removing AMC or moisture inside the FOUP. This study used the design of leading diffuser tubes in the FOUP and pores in the surfaces of diffuser tubes to generate gas diffusion. This is to achieve a uniform distribution of the wafer surface velocity field and a uniform dehumidification function of the wafer surface. Based on the analysis results, when circular diffuser tubes are introduced in the FOUP and the intake air flow was set at 0.2-0.3 m³/hr, the interlayer wafer surface in the FOUP could achieve uniform distribution of velocity field. As a result, the humidity difference among various zones of wafer surface could be reduced, and the yield and quality of the wafer cutting process could be controlled.

Abstract: In this study eggshells and low density polyethylene plastic (LDPE) wastes were reused to produce tiles. The eggshells were ground in a laboratory scale jar mill into the particle size of fine sand. The optimum grinding parameters were determined to be the setting that produced the highest mass of eggshell powder that was within the desired particle diameter size range of 0.425 mm (No. 40) and 0.075 mm (No. 200). A two to the three factorial design of experiment was used with variables of Time, Speed, and Ball Filling Ratio. The high and low values used in this study were 20 minutes and 10 minutes for the time, 250 rpm and 100 rpm for the speed, and 35% and 20% for the ball filling ratio. There were eight settings made with 3 trials per setting and one validation for the optimal setting produced. The eggshell powder produced by the optimal setting of the jar mill was used to create the LDPE-eggshell tiles. Four tiles were made for the three trials and for the validation part. The tiles were tested for its relative strength using the Compression Testing Machine. The researchers determined that eggshells and LDPE plastics may be formed into tiles and that the strength of the tiles that were produced by these materials exceeded the standard value set for this type of product.

Abstract: This presentation focuses on semiconductor wafer cleaning technology, one of the most critical technologies in semiconductor device manufacturing for obtaining high yield and reliability, and discusses the past, present, and future of the technology. Emphasis is placed on the review of contamination control and cleaning technologies in the early days since the invention of the transistor. To celebrate the 30+1-year anniversary of the UCPSS, a review will be given of both the first conference held in Leuven in 1992 and the second one held in Bruges in 1994. There will be more research challenges and business opportunities in environmentally benign, innovative damage-free wafer cleaning and surface preparation technologies for future applications.

Abstract: There is a lack of information on the magnetic properties of particles of such materials as powder magnetic (modified by inclusions of magnetite and maghemite) carbon sorbents intended for water purification from various kinds of impurities and, what is especially important, allowing to perform the prompt isolation of the spent sorbent – by magnetic separation. The data on the magnetic susceptibility χ of the particles of these sorbents, found by the developed experimental calculation method based on the concept of the corresponding magnetometry of a moderately rarefied dispersed sample with a dispersed phase of the particles under study, are presented. Experimental dependences of the magnetic susceptibility of <χ>of a dispersed sample on the volume fraction γ of controlled particles in it have been obtained - for different values ​​of the magnetic field strength H in the range from 22 to 61 kA/m, i.e. in the postextremal region for the susceptibility. In addition to the necessary assessment of their linear, located at γ ≤ 0.15-0.2, sections, this also made it possible to find and phenomenologically describe the field dependences of the generalized data of the reduced susceptibility of <χ>/γ, i.e. data χ: in the form of an inverse power function with a power of 0.7 ... 0.8 at H.

Abstract: The objective of this research is to study the effect of water content on particle characterization and agglomeration of bamboo charcoal resulted from ball milling process. The characterization is determined by the particle size and the morphology of the particle. The milling was performed in cylinder vial of stainless steel. The element of milling is steel balls. The dimension of the cylinder vial was 120 mm length and 1-inch diameter, while the ball diameter was 5/32 inch. The charcoal resulted from pyrolysis was milled manually then strained with a filter size of 200 meshes. The particles passing the strainer were washed in water and then dried to obtain 25%, 28%, 32% and 35% water content. Then they were put together with the milling balls into cylinder vial. There were four vials with a water content of 25%, 28%, 32% and 35% respectively for milling process. Every vial contained 11 grams of bamboo charcoal and approximately 299 grams of steel balls. It represents 1/3 of vial volume for charcoal, 1/3 of vial volume for ball and 1/3 of vial volume for empty space. Two type tests were conducted. The first test was to run the milling machine at 700 rpm for 2 million cycles and the second test was to run the milling machine at 1000 rpm for 3 million cycles. Particulate characterization was done by a particle size analyzer (PSA), a scanning electron microscope (SEM) with energy dispersive X-Ray (EDX). The results showed that the water content does not have any influenced to the particle size. For the both test the particle sizes are in the range of 100 nm or less to more than 1 μm. However, the second test produces smaller particles and a higher number of smaller particles due to higher impact energy and longer milling time. The two tests inform that agglomeration does not happen by having wet milling. The dominant element of the bamboo charcoal is carbon with more than 90% in number.

Abstract: This paper reports the preliminary study on the synthesis of Ni doped CZTS (Cu₂ZnSnS₄:Ni) particle 5 at.% of Cu by solution method and dispersion of the obtained particles by beads mill method at various dispersing agents (SDS, CTAB, and Tween80). The phase transformation of the obtained particles was analyzed from the XRD spectra and XRF elemental analysis. The phase transformation and amount of Ni-doped to particles was predicted employing commercially available analytical software tool Match! Version 2.x. Moreover, the dispersion characteristics were investigated includes size, size distribution, and zeta potential of bare particles in comparison to various dispersing agents. This characteristic related to the future application of CZTS as an absorber in a thin-film based PV. The XRD analysis showed that the obtained particle contained crystal structure of copper sulfate pentahydrate (75.9 %), Ni(HN₂S₂)₂ (12.5 %), and Cu₂ZnSnS₄ (11.6%). The XRF elemental analysis showed that amount of Ni-doped was 6.8 at.%; it was higher than the initial design amount of Ni doping. The dispersion of suspended particles was the majority (90%) with an average size of 3.06 µm and only 10 % with size 255 nm. Beads-milling of particles without dispersing agents did not disintegrate agglomerated particles. It is highlighted dispersion only using magnetic stirred with SDS dispersing agent provides the best suspension with a majority (60%) in 166 nm and only 30 % with average size 3.06 µm with relatively high zeta potential (-17 mV). It was concluded that the presence of a multi-phase crystal needs to be resolved either by proper calcination at a higher temperature than 400°C or further heating at a higher temperature during film preparation. High-energy centrifugation of zirconia beads mill caused desorption of adsorbed steric stabilization of dispersing agent under investigation. Further investigation on the coating process to facilitated laboratory fabrication of thin-film absorber with SDS as a dispersing agent is necessary to carry out concerning the properties of the thin-film.

Abstract: The objectives of this work are to prepare keratin/egg white blend particles by emulsification solvent diffusion method and characterize their properties. The different factors including concentration, water: oil phases, spinning rate, and blending ratio were optimized. The morphological observation indicated that the shapes and sizes of particles were variable by the condition used. FTIR spectra indicated that all particles co-existed of α-helix and random coil structures. The decomposition rate of all particles found at least 4 steps and the blend particles have lower Td, max than the native protein particles. The obtained results were advantaged for the development of the keratin/egg white blend particles for specific applications such as drug-controlled release systems.

Abstract: The article presents the results of experimental studies of differences in the nature of impact destruction of single garnet grains penetrating the target material, and presents the results of numerical simulation (modeling) of the contact interaction of an abrasive particle with a flat obstacle, which allowed determining the volume ablation of the material under the action of a single abrasive particle, and makes it possible to predict the performance of waterjet cutting.