Papers by Keyword: Injection

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Authors: Jia Rui Jin, Yuan Zhi Chen, Hui Zhang Guo, Zhen Wei Wang, Dong Liang Peng
Abstract: A non-aqueous synthetic route has been developed for the preparation of uniform Cu nanowires with length up to tens of micrometers. Unlike commonly used one-pot synthesis approach that usually involve a fast reduction of metal precursors in the presence of reducing agents, a continuous-injection approach has been to utilized to control the speed of reaction and the concentration of Cu nuclei. In this approach, copper (II) chloride dihydrate and nickel (II) acetylacetone which are dissolved in oleylamine solutions have been injected into octadecene by a syringe-pump. The as-prepared samples have been characterized by transmission electron microscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy. The results show that the products are pure Cu nanowires which have preferred <110> growth directions. The formation mechanism and major influencing factors on the synthesis of Cu nanowires have been discussed.
Authors: Nanthida Wonglertnirant, Tanasait Ngawhirunpat, Praneet Opanasopit, Hiroaki Todo, Kenji Sugibayashi
Abstract: Delivery of drugs through skin is obstructed by the excellent barrier properties of the outermost skin layer, the stratum corneum (SC). A strategy employing microneedles have recently emerged as a minimally invasive device for disrupting the SC structure and creating holes for molecules to pass through. Hollow-typed microneedles permit drug delivery which can be modulated over time via active delivery controlled by hand or pump. In this study, the potential of hollow microneedle for overcoming the outermost skin barrier and facilitating drug delivery into skin was investigated. Fluorescein isothiocyanate (FITC)-dextrans (4.3 kDa), FD-4, was used as a model large molecular compound. The effects of injection volume and formulation on drug release behavior from skin were determined. FD-4 was favorably loaded into the lower epidermis as well as the superficial dermis of the skin by a hollow microneedle. The release profiles of FD-4 were analyzed by Higuchi model based on Fick’s law of diffusion. The higher the volume of FD-4 solution injected, the faster the FD-4 release rate from skin. Liposome formulation exhibited no difference on drug release profiles compared with the solution. The results provide information for designing an effective hollow microneedles system.
Authors: Adiba Rhaodah Andsaler, Amir Khalid, Him Ramsy, Norrizam Jaat
Abstract: This paper describes simulation of combustion characteristics under high ambient and high injection of biodiesel combustion by using CFD simulation. Diesel engine performance and emissions is strongly couple with fuel atomization and spray processes, which in turn are strongly influenced by injector flow dynamics. The principal objective of this research is to seek the effect of temperature and pressure on the spray characteristics, as well as fuel-air mixing characteristics. Experiments were performed in a constant volume chamber at specified ambient gas temperature and pressure. This research was continued with injecting diesel fuel into the chamber using a Bosch common rail system. Direct photography technique with a digital camera was used to clarify the real images of spray pattern, liquid length and vapor penetration. The method of the simulation of real phenomenon of diesel combustion with optical access rapid compression machine is also reviewed and experimental results are presented. The liquid phase of the spray reaches a maximum penetration distance soon after the start of injection, while the vapor phase of the spray continues to penetrate downstream. The condition to which the fuel is affected was estimated by combining information on the block temperature, ambient temperature and photographs of the spray. The increases in ambient pressure inside the chamber resulting in gain of spray area and wider spray angle. Thus predominantly promotes for a better fuel-air mixing. All of the experiments will be conducted and run by using CFD. The simulation will show in the form of images.
Authors: Tae Il Seo, Byeong Uk Song, Yong Seok Lim
Abstract: This paper presents a series of injection process simulations for blow molding preforms by using MoldFlow. The injection-blowing system was used and this consists 3 stages on the same machine; (1) preform injection, (2) blowing and (3) ejection. The quality of preform injection process is an important factor that can dominate the whole process efficiency. The injection mold system consists of 10 cavities and a hot runner system. The hot runner system has 10 cavities and temperature of each cavity can be independently controlled. Through several filling analyses, suitable temperature of each gate was determined so that all cavities could be simultaneously filled. Weld lines on the bottom of preforms were predicted. This fact can be an important aspect because preforms will be blown. To improve cooling efficiency, ''Floody Cooling Type" channels were applied. Conventional cooling channels were straight-line types and then distances between cooling channels and cavities cannot be uniformed. Floody cooling type channels were uniformly placed around cavities as far as possible. To compare two different types of cooling channels, cooling tests of MoldFlow were carried out and certain advantages of floody cooling type channels were evaluated.
Authors: Deepesh Kumar Singh, Gautam Bandyopadhyay
Abstract: Active flow control methods are used to reduce the aerodynamic drag over a car model. Method of Boundary layer suction at the top rear and air injection at the back of the car are used as the active flow control tools to suppress the aerodynamic drag. The computational results obtained using the standard model for the car model are verified first against the practical results obtained by wind tunnel experimentation so as to obtain the range of turbulence. Then a parametric study on the effect of the drag and lift coefficient of the car with respect to the parameters governing the active flow control is done. The drag coefficient is reduced by 20.25% using this strategy with 19.4% increase in the lift coefficient.
Authors: Erdal Akyol, Suat Tasdelen, Ali Aydin
Abstract: Uncontrolled growing of construction industry in Turkey has caused a large number of buildings were constructed without the benefit of sufficient engineering supervision. These phenomena have contributed to the increase in the number of seismically weak buildings. After the Great Marmara Earthquake seismic performances of the existing structures have been inspected and some of them fortified. In this context, an existing building foundation, built on a problematic soil and located in Denizli where is in high seismic risk area, has been strengthened by cement injection. Grouting holes up to 7 m in depth from the basement level were used in 45 points. The injection has created a less permeable barrier, acts like an underground dam. This barrier has caused rising of the underground water table around the recharge area of the foundation. The raised underground water has increased hydraulic gradient and hydraulic pressure. Then, the basement floor has arched up to 12 cm and underground water has risen up to 30 cm high after one year of the injection practice. In this study, hydrogeological characteristics of the soil structural analysis have been evaluated and some solutions suggested remedying the problem. It should be kept in mind as injection practice is employed in aquifers.
Authors: Thawatchai Phaechamud, Sarun Tuntarawongsa
Abstract: Capsaicin exhibits the analgesic and anti-inflammatory activities, therefore it is interesting to apply this natural active compound for periodontitis treatment by local drug delivery system such as intra-canal route. Capsaicin in-situ forming gels were prepared in this research work. The viscosity, gel forming property and capsaicin release were evaluated. 30%W/W eudragit RS 30D in N-methylpyrrolidone (NMP) employed as gel base was physicaly stable after sterilization with autoclaving and exhibited the in-situ forming gel property. This gel base was still clear when capsaicin was less than 0.0094 %w/w. When the system contacted with phosphate buffer pH 6.8 the turbid gel was appeared rapidly at the interface. Viscosity of system depended on the amount of eudragit RS 30D. The rheology of systems was newtonian flow and amount of capsaicin tincture did not affect the rheological behavior. The release rate and amount of capsaicin release form gels were lower than those of capsaicin solution. The sustainable release of capsaicin could be obtained from the developed in-situ forming gel.
Authors: Tapany Udomphol, Benchawan Inpanya, Nutthita Chuankrerkkul
Abstract: Characterization of feedstocks for powder injection molding of SiCp-reinforced aluminium composite, as potential use for automotive and light-weight applications, has been studied in this research. Al-4.5 wt.% Cu powder, SiCp and polymeric binder were pre-mixed and compounded using a twin screw extruder at 170oC prior to powder injection molding at 170 oC. Effects of varied solid loadings at 52, 55 and 58% on green properties of the feedstocks have been investigated. Experimental results showed that compounding followed by powder injection molding allowed uniform distribution of SiCp surrounding the aluminium powder. It was found that higher solid loading improved bulk density while hardness values were observed to be similar. Molded specimens of 55% solid loading provided the optimum bend strength and strain at failure. Moreover, it was observed that the opposing abrasive property with angular shape of SiCp resulted in SiCp scratching effect, leading to irregular surface of aluminium powder after injection molding. This consequence and molding porosity were expected to be responsible for relatively low density of the molded specimens, giving the difficulty in molding at higher solid loading.
Authors: Kent Bertilsson, Chris I. Harris
Abstract: Both unipolar and injection SiC devices can be used for high voltage switching applications; it is not determined, however, for which applications one approach is preferred over the other. In this paper, simulation studies are used to compare the suitability of unipolar devices, in this case a JFET (Junction Field Effect Transistor) against an equivalent FCD (Field Controlled Diode) configuration up to very high voltages. The calculations are performed in a finite element approach, with commercial drift-diffusion software. Numerous drift layers have been simulated in a Monte-Carlo approach to ensure that the optimal design of the drift layers for different breakdown is used. In a static case, purely conductive losses in the drift layer in both unipolar and injection configuration are compared. Additionally the total losses are studied and compared in switched applications for different switching frequencies and current levels.
Authors: Simona Plavanescu, Dumitru Nedelcu, Nicoleta Monica Lohan
Abstract: The researches made in the last years have shown that lignin is a substance that gives wood strength. It can be found in the granular form that can be melted and injected. Lignin is used to obtain material with multiple uses such as electronics, food containers etc. This material is known as "liquid wood". Fibers with high specific resistance and high elasticity modules, such as aramid fibers, are used to create high performance composites. Here are the main physical-mechanical properties of aramid fibers: high tensile strength, high shock resistance, high stresses and fatigue, excellent characteristics of damping vibrations, exposure characteristics preservation at temperatures ranging from-700C to + 1800C, flame resistance (self-extinguishing, not melting), low smoke emission, corrosion stability, good electrical characteristics, low conductivity and low dielectric constant. The main areas of use of aramid wires are: special clothes resistance to cutting and high temperature components for materials composite, ropes, cables, lashing straps, safety equipment for the armed forces, police, aircraft, etc. This research used Arboform L, V3 Nature reinforced with aramid fiber. The experimental research plan observes the Taguchi methodology with 6 input factors, each with two levels of variation. The input parameters effects are analyzed on the mechanical properties of the specimens obtained. Micro-indentation tests and differential scanning calorimetry were conducted. The studied test samples showed the following mean recovery values: 31.219μm for the first sample, 31.059μm for the second sample and 25.996μm for the third sample. Three extreme points were detected on the DSC thermogram: an endothermic peak occurs up to 380 K (I) and an exothermic one of higher intensity (II); above 430 K the DSC thermogram shows a deviation from linearity of the flow heat, which suggests a melting phenomenon. The first variation of the heat flow can be attributed to the transformations that occur in solid form in the sample subjected to heating, the first adsorption heat exchanger (peak I) and the second heat releasing (peak II). Comparing the amount of heat absorbed by heat dissipation, one may notice that the exothermic conversion is increased. The initial transformation temperature (Ts 10) corresponds to 10% of the total peak area while the final transformation temperature (Tf 90) corresponds to 90% of the total surface area.
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