Papers by Keyword: Fluid

Abstract: Preparation of telechelic hydroxyl low molecular weight fluoropolymers by reduction reaction was presented. The telechelic carboxyl low molecular weight fluoropolymers were chosen as raw materials which were prepared by oxidative degradation method. The molecular weights of telechelic carboxyl low molecular weight fluoropolymers were about 3700. Then, using lithium aluminum hydride reacted with carboxyl groups to prepare the telechelic hydroxyl low molecular weight fluoropolymers. The effects of reaction temperatures, reaction times, contents of solvent and lithium aluminum hydride were investigated in detail. The structures, Mn and dynamic viscosity of low molecular weight fluoropolymers were analyzed by FTIR, ¹H-NMR, GPC and viscometer respectively. Finally telechelic hydroxyl low molecular weight fluoropolymers were prepared. The conversion rate of that reduction reaction was about 95%. The product was a viscous fluid with a dynamic viscosity of 48Pa·s at 50°C.

Abstract: This work studied the turbulent flow of the nutrient solution which affected the growth of plants in four hydroponic systems; the horizontal (traditional), the vertical cup-grown, the ladder and the droplet systems, which were connected with individual solution pumps which submerged in only one nutrient solution tank to supply the turbulent nutrient solution flow to all systems. Two experiments were done by planting Red Oak lettuce, fluid and ambient temperatures, fluid pH and sunlight intensity were measured 2 times a day from 4 systems placed in the same area and environment during 20 days of the experimental periods. From both result sets, the lower ambient and solution temperatures in the 2^nd experiment yielded more productivity. The results also showed that adjusting pipe and hose sizes did not cause the nutrient solution overflow out of the systems, the turbulent flow occurred and the horizontal system could produce the highest productivity. However, the higher pump power was required to produce the turbulent solution, the higher pump power higher heat transfer from the pump to the nutrient solution in the tank since all pumps were placed in the same solution tank, this heated solution caused the lower productivity in this work.

Abstract: Both conductivity and thermal resistivity measurements of commercial graphite dispersions in non-aqueous polar fluids and non-polar fluids were carried out. Fluids exhibiting different densities as: mineral oil, ethylene glycol, glycerin bidistilled and liquid vaseline were used. Dispersions of commercial graphite containing 5, 10, 20, 40, 60 and 80 weight percent were prepared by sonication technique. The thermal conductivity of each fluid increases as a function of the increasing of the volumetric density of fluid and of the fraction of graphite. Values of thermal conductivity of graphite dispersion were at around ten times higher than that value of the base-fluid. Effects of processing parameters of graphite dispersions on the magnitude of its thermal conductivity are discussed.

Abstract: The cooling systems on machine tools are particularly important; these have a positive influence on the cutting operation and the quality of machined surface. A particular importance represent finding an optimal correlation between the lubricant and coolant used, the material to be processed, processing method and the cutting regime. A high temperature in the working area over a certain value allowable can be harmful in terms of both the resulted surface quality and repercussions on the life of the cutting tool. The parameters of the cooling-lubricating fluid flow can be influenced by the nature of the fluid or fluids, or the nozzle geometry used, which generally has a convergent-divergent geometry in order to achieve a better dispersion of the coolant/lubricant on the area to be machined.

Abstract: The use of hydrostatic guideways in CNC machine-tools is very common as a result of their low friction coefficient. The major problem of hydrostatic guideways represents the recovery of the fluid used in guideways, where the fluid should be protected against mechanical impurities and then led towards the hydraulic aggregate. The floating support described in this paper resolves the collection of fluid by using a closed circuit, without exposing the fluid to mehanical impurities and to a gravitational collecting.

Abstract: This work studied fluid flow in the hydroponics systems to create 4 prototypes of the hydroponics systems; horizontal (traditional), inclined-flow, vertical-droplet and vertical-bowl systems, for a household application with initial conditions as low investment cost and easy installation. Red Oak was used to plant in all prototypes to investigate the prototype productivity. Fluid in the experimental investigation was the plant nutrient solution. All variables; fluid and ambient temperatures, fluid pH and sunlight intensity were measured 2 times a day from 4 systems placed in the same area and environment during 15 days of the experimental period in July 2013,. From results, the solution temperatures affected the productivity less than the fluid flow patterns did. The vertical-droplet system could not be used to grow Red Oak because the plants died during the experiment period. The vertical-bowl system could provide the highest productivity. We noticed that the fluid in the vertical-bowl system flowed transitionally while the flow in the other systems was laminar. Therefore, the fluid flow patterns could affect the productivity in the hydroponics systems.

Abstract: Lithium-ion batteries have been the dominant energy storage technology in consumer electronics for several years and meanwhile advanced into e-mobility and stationary applications. The trend towards large-scale batteries presents manifold challenges to production technology. One decisive assembly process is filling electrolyte liquid into the battery case. This paper discusses the main influences and challenges for production technology concerning this crucial manufacturing process and how they are addressed. First preliminary results are presented.

Abstract: This paper deals with the determination of eigenfrequencies of high steel cylindrical storage tank. The eigenfrequencies have been determined for empty tank and also for the tank with fluid. Water levels varied in the range from 10 cm to 80 cm, with the step 10 cm. The task was solved by 3D computing model. The results were verified by the tests made on real structure in scale 1:1. Total dimensions, a material, the description of created computing model, applied loads, the descriptions of measuring devices and the tests are mentioned here. Obtained results and future plans are discussed at the end of the paper.

Abstract: Ground-supported tanks are used to store a variety of fluids. The liquid develops a hydrodynamic effect on walls and bottom of the tank during earthquake. This paper presents influence of mesh parameter “PATTERN” for numerical model fluid region of liquid seismic response in rectangular tank – endlessly long shipping channel. Finite Element Method (FEM) was used in software Adina.

Abstract: The electric valve, cutting off or connecting pipeline of nuclear equipment, is an essential component of nuclear facilities for safe operation. The structure of self-developed enclosed nuclear electric valve is introduced in the paper firstly, and dynamics analysis of steam fluid in valve is carried out to tackle typical problems including leakage in the rapid open-close process of valve for high-temperature and high-pressure steam fluid. It can be determined that dynamic characteristic of steam fluid will directly affect force suffered by valve in the rapid open-close process, greatly influencing movement and ultimate position accuracy of valve gate.