• Steel and Composite Structures
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• 제18권2호
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• pp.345-355
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• 2015

In this study, the effects of weld parameters on nugget size and tensile-shear strength of welding joint in electrical resistance spot welding of galvanized DP 600 steel sheets having 1.2 mm were investigated. Taguchi design method has been employed to examine the effects of five parameters of welding current, electrode pressure, welding time, clamping time and holding time by using the $L_{27}(5^3)$ orthogonal array. Results showed that the most effective parameters on tensile shear strength and the nugget size ratio (hn/dn) were found as welding current and welding time, whereas electrode pressure, clamping time and holding time were less effective factors. Max. 545 MPa strength was obtained through proposed optimum conditions by Taguchi technique.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 춘계학술대회 논문집
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• pp.70-75
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• 2004

In this study, the pattern of lens aberration was studied at different injection molding conditions such as injection speed, holding pressure, holding pressure time, mold temperature and cylinder temperature and, then, the results were analyzed with a laser interferometer. It was demonstrated that optimal condition of lens aberration could be achieved by adjustment of injection molding conditions.

• International Journal of Fluid Machinery and Systems
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• 제3권4호
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• pp.315-323
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• 2010

This work investigates the influence of water compressibility on pressure pulsations induced by rotor-stator interaction (RSI) in hydraulic machinery, using the commercial CFD solver ANSYS-CFX. A pipe flow example with harmonic velocity excitation at the inlet plane is simulated using different grid densities and time step sizes. Results are compared with a validated code for hydraulic networks (SIMSEN). Subsequently, the solution procedure is applied to a simplified 2.5-dimensional pump-turbine configuration in prototype with different speeds of sound as well as in model scale with an adapted speed of sound. Pressure fluctuations are compared with numerical and experimental data based on prototype scale. The good agreement indicates that the scaling of acoustic effects with an adapted speed of sound works well. With respect to pressure fluctuation amplitudes along the centerline of runner channels, incompressible solutions exhibit a linear decrease while compressible solutions exhibit sinusoidal distributions with maximum values at half the channel length, coinciding with analytical solutions of one-dimensional acoustics. Furthermore, in compressible simulation the amplification of pressure fluctuations is observed from the inlet of stay vane channels to the spiral case wall. Finally, the procedure is applied to a three-dimensional pump configuration in model scale with adapted speed of sound. Normalized Pressure fluctuations are compared with results from prototype measurements. Compared to incompressible computations, compressible simulations provide similar pressure fluctuations in vaneless space, but pressure fluctuations in spiral case and penstock may be much higher.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 추계학술대회 논문집
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• pp.259-264
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• 2005

The shrinkage of the product in injection molded part occurs due to the volume change with variation of temperature and pressure and is influenced by the processing conditions of injection molding. Mold designers greatly concerns the shrinkage of parts for a high dimensional accuracy. In this study, bar type HIPS specimen with 15x19 grid on the surface was tested. The amount of shrinkage of flow and transverse directions was examined with respect to the injection molding conditions such as melt temperature, injection speed, holding pressure, mold temperature and cooling time. As the packing pressure increased, the difference of shrinkage of both directions is decreased and the absolute shrinkage value also decreased.

• 소성∙가공
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• 제21권1호
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• pp.30-35
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• 2012

FIM(Film Insert Molding) is an innovative method of producing decorated parts for a wide range of products. Because it requires fewer steps when compared to conventional production methods, the time and cost of manufacturing high quality components can be reduced considerably. In this paper, the effects of processing conditions on the warpage of film-insert molded plate were investigated by using a design of experiments. The dominant factors affecting warpage were mold temperature and holding pressure. Warpage increased with the temperature difference between stationary mold and fixed one. Even when the mold temperature difference was zero, the plate with a film was bent after ejection such that the film side protruded. As holding pressure increased, warpage decreased significantly. In addition warpage increased with time increment for the film-insert molded plates.

• 한국축산식품학회지
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• 제33권4호
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• pp.474-480
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• 2013

This study was performed to investigate the effects of high pressure/high temperature (HPHT) treatment on the recovery efficiency and characteristics of porcine placenta hydrolysates. The placenta hydrolysates were characterized by solubility, free amino acid contents, gel electrophoresis, gel permeation chromatography (GPC) and amino acid composition. Placenta was treated at 37.5 MPa of pressure combined with various temperatures (150, 170, and $200^{\circ}C$) or various holding times (0, 30, and 60 min at $170^{\circ}C$). Insoluble raw placenta collagen was partially solubilized (> 60% solubility) by the HPHT treatment. Free amino group content of placenta collagen was increased from 0.1 mM/g collagen to > 0.3 mM/g collagen after HPHT treatment, reflecting partial hydrolysis of collagen. The molecular weight ($M_w$) distribution showed evidence of collagen hydrolysis by shifting of $M_w$ peaks toward low molecular weight when treated temperature or holding time was increased. Alanine (Ala), glycine (Gly), hydroxyproline (Hyp), and proline (Pro) contents increased after the HPHT treatments compared to a decrease in the others. In particular, the increase in Gly was obvious, followed by Hyp and Pro, reflecting that placenta hydrolysates were mainly composed of these amino acids. However, increasing temperature or holding time hardly affected the amino acid compositions. These results indicate that the HPHT treatment is advantageous to hydrolyze collagen derived from animal by-products.

• 한국염색가공학회지
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• 제10권6호
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• pp.1-9
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• 1998

The effects of oxygen plasma treatments at different discharge power, reaction pressure, treatment time on yellowing of polyester fabrics were studied. Surface characteristics of the treated fabrics were also investigated by means of SEM and ESCA. The results were as follows : The yellowing of fabrics increases as the power and the treatment time are increased, and decreases as the pressure is increased. The plasma treatment of 100 Watt, 200 mTorr, 5 min. is the optimal condition which is most effective in holding whiteness as well as high weight loss of fabrics.

• Design & Manufacturing
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• 제10권3호
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• pp.30-33
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• 2016

It is true that the plastic shrinkage is inevitable. Shrinkage rate in effect at the time of mold design will soon determine the size of the global product. Process for the shrinkage of the plastic that provides how made, yet it has identified a process for making the question whether the shrinkage that can be trusted, and by the experimental results were as follows: as shrinkage, see ISO but, according to circumstances the process can go to the agreement between the parties. shrinkage ratio of the pressure sensor installed in the specimen mold is essential, amount of pressure sensor is that it is appropriate approximately 2-3. proper holding pressure is a significant effect on shrinkage Mitch, so that the effect of selecting the contraction ratio data according to the appropriate holding pressure during mold making. shrinkage CAE analysis results are difficult to utilize in the mold-making chamber. Based on these results, it concluded by looking forward to the improved products produced shrinkage.

• Food Science and Biotechnology
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• 제14권6호
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• pp.808-812
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• 2005

The effects of high pressure processing, pressure level (50, 100, 150, and 200 MPa) and pressurized time (0, 5, 10, 15, 30, 45, and 60 min) on the physico-chemical properties of pork M. longissimus dorsi were evaluated. The pH value was affected by both pressure level and pressurized time, especially at 200 MPa (P<0.05). In color measurement, $L^*$ and $a^*$-values were increased by both pressure level and pressurized time, but $b^*$-value did not differ significantly (P>0.05). Water holding capacity (WHC) was significantly decreased (P<0.05) depending on pressure level and pressurized time, while cooking loss was gradually increased. Warner-Bratzler shear force did not differ significantly (P>0.05) among the treatments. These results indicate that high pressure processing below 200 MPa for 1 hr had no effect on the quality of cooked meat, although some alterations were observed before cooking.

• 소성∙가공
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• 제18권8호
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• pp.616-624
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• 2009

In this work we demonstrate the hot-embossing process under different forming conditions such as forming temperature, load, and holding time in pressing, in order to determine the suitable conditions required for linear patterning on polymer plates (PC). Results showed that the replicated pattern depth increased in proportion to an increase in the forming temperature, load, and time. The reduction of the workpiece thickness increased according to the holding time in the pressing process. In the process of time, the reduction ratio of the workpiece thickness decreased due to the surface area increment of the workpiece, while the pressure on the workpiece declined. In order to reduce the bulging ratio we introduced a temperature difference between the upper and the lower punch.