• 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.

• Geomechanics and Engineering
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• 제11권6호
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• pp.805-820
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• 2016

A fully coupled non-linear effective stress response finite difference (FD) model is built to survey the counter-intuitive recent findings on the reliance of pore water pressure ratio on foundation contact pressure. Two alternative design scenarios for a benchmark problem are explored and contrasted in the light of construction emission rates using the EFFC-DFI methodology. A strain-hardening effective stress plasticity model is adopted to simulate the dynamic loading. A combination of input motions, contact pressure, initial vertical total pressure and distance to foundation centreline are employed, as model variables, to further investigate the control of permanent and variable actions on the residual pore pressure ratio. The model is verified against the Ghosh and Madabhushi high acceleration field test database. The outputs of this work are aimed to improve the current computer-aided seismic foundation design that relies on ground's packing state and consistency. The results confirm that on seismic excitation of shallow foundations, the likelihood of effective stress loss is greater in deeper depths and across free field. For the benchmark problem, adopting a shallow foundation system instead of piled foundation benefitted in a 75% less emission rate, a marked proportion of which is owed to reduced materials and haulage carbon cost.

• 한국수산과학회지
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• 제35권1호
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• pp.8-14
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• 2002

신제조기법과 재래식방법으로 제조된 창란젓갈을 각각 병포장하여 10, 20, $30^{\circ}C$에 저장하면서 품질변화를 조사하였으며, 이들을 시험구와 대조구라 하였다. 각 온도별 압력을 측정한 결과, 시험구와 대조구 모두 저장 중 압력이 증가하는 경향을 나타냈으나, 시험구가 대조구에 비해 저장 중의 압력증가 속도가 완만하였다. 저장 초기에는 온도에 관계없이 head space의 $CO_2$ 발생 속도는 크게 증가하고 상대적으로 0,는 급격히 감소하는 경향을 나타내었다. 저장기간에 따른 총 $CO_2$의 변화는 온도가 높을수록 초기 발생속도가 컸으며 대조구에 비하여 시험구는 증가속도가 낮게 나타났다. 다만, $10^{\circ}C$에서는 20일 이후 총 CO, 농도가 다소 감소하는 경향을 나타내었다. 창란젓갈 저장 중 온도가 높을수록 pH의 저하 속도가 빨랐으며, 시험구는 대조구보다 pH 변화가 적었다. 휘발성염기질소 (VBN)의 경우 각 온도에서 시험구가 대조구보다 VBN이 낮았으며, 그 증가율도 낮았다. 생균수변화에 있어서도 시험구는 대조구보다 생균수 증가 속도가 완만하였다. 창란젓갈의 저장 중 색도는 온도가 높을수록 그리고 저장기간이 경과할수록 L값이 증가하였으며, 수분활성도가 낮은 시험구$(A_w 0.82)$가 대조구 $(A_w 0.90)$보다 동일조건에서 L값이 낮았다. 창란젓갈을 병포장하여 온도별로 저장하면서 관능검사를 실시한 결과 품질유지기한이 대조구와 시험구는 $10^{\circ}C$에서 각각 40일과 70일, $20^{\circ}C$에서 8일과 16일, $30^{\circ}C$에서는 2일과 4일로 결정되었다. 따라서 병포장에서 $A_w$가 낮은 시험구는 $A_w$가 높은 대조구보다 품질유지기한이 10, 20, $30^{\circ}C$에서 각각 30일, 8일, 2일이 연장되었다. 창란젓갈 저장시 품질측정변수에 대한 상관관계를 조사한 결과병포장에서는 용기내 압력, pH, L값, VBN, 관능검사 등이 상관관계가 높아 젓갈 포장에서 품질지표항목으로 이용할 수 있을 것으로 기대된다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제32권2호
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• pp.189-195
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• 2010

Excessive oral and maxillofacial bleeding causes upper airway obstruction, bronchotracheal & gastric aspiration and hypovolemic shock. Therefore, the rapid & correct bleeding control is very important for life-saving in the medical emergency room. In spite of the bleeding control methods of the wound suture & direct pressure, the postoperative bleeding can be occurred, because of the presence of various bleeding disorders & postoperative delayed wound infections. The proper care of bleeding disorders & wound infections are very important for the control of the delayed postoperative rebleeding. In spite of these methods, active oral bleeding can be presented by the other causes of head injury. A rare but particularly dangerous sort of bleeding that may have an especial importance to the patient with severe basal skull fracture that damage large vessels and even the cavernous sinus. The occurrence of profuse nasal or oropharyngeal bleeding may arise from damage to the anterior and posterior ethmoidal vessels, but when mixed with brain tissue it is evidence of mortal damage. In this condition, rapid entire oropharyngeal packing is essential for the control of active oral bleeding. This is a case report of rapid rational bleeding control method by much amount of wet gauze packings, in a 44-years-old male patient with active oropharyngeal bleeding by basal skull fractures.

• Journal of Trauma and Injury
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• 제30권4호
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• pp.238-241
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• 2017

A 52-year-old man experienced blunt trauma upon falling from a height of 40 m while trying to repair the elevator. The patient's systolic blood pressure and hemoglobin levels were 60 mmHg and 7.0 g/dL, respectively, upon admission. A large volume of bloody discharge was observed in the open wound of the perianal area and sacrum. A computed tomography scan revealed an open comminuted sacral fracture with multiple contrast blushes. He underwent emergency laparotomy. Both internal iliac artery ligations were performed to control bleeding from the pelvis. Protective sigmoid loop colostomy was performed because of massive injury to the anal sphincters and pelvis. Pad packing was performed for a sacral open wound and perineal wound at the prone position. After resuscitation of massive transfusion, he underwent the second operation 2 days after the first operation. The pad was removed and the perineal and sacral open wounds were closed. After the damage-control surgery, he recovered safely. In this case, the hemodynamically unstable, open comminuted sacral fracture was treated safely by internal iliac artery ligation with pad packing.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1715-1720
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• 2004

This paper presents the characteristics of internal clearances for the interstage of blades and shaft gland seals on the steam turbine which are installed in tandem compound. Internal clearances was changed when the rotor turned in the cylindrical sleeve bearing due to the generation of oil film wedge. This presented concern is very useful to prevent the rubbing damage of seal edge between the fixed and moving parts in steam turbine due to the misalignment at the rotating and stationary parts. This method is applied for the unbalanced clearances distribution to the left and right sides in the turbine casing. A considerable amount of unbalanced clearances distribution trend is determined according to the rotating speed of rotor, size and type of proceeding bearing, oil viscosity, surface roughness of bearing and shaft, oil temperature, oil pressure and bearing load.

• Design & Manufacturing
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• 제14권3호
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• pp.1-7
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• 2020

This paper predicts the mass and the length of injection-molded products through the Artificial Neural Network (ANN) method. The ANN was implemented with 5 input parameters and 2 output parameters(mass, length). The input parameters, such as injection time, melt temperature, mold temperature, packing pressure and packing time were selected. 44 experiments that are based on the mixed sampling method were performed to generate training data for the ANN model. The generated training data were normalized to eliminate scale differences between factors to improve the prediction performance of the ANN model. A random search method was used to find the optimized hyper-parameter of the ANN model. After the ANN completed the training, the ANN model predicted the mass and the length of the injection-molded product. According to the result, average error of the ANN for mass was 0.3 %. In the case of length, the average deviation of ANN was 0.043 mm.

• Design & Manufacturing
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• 제16권3호
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• pp.1-8
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• 2022

In this study, an artificial neural network(ANN) was constructed to establish the relationship between process condition prameters and the qualities of the injection-molded product in the injection molding process. Six process parmeters were set as input parameter for ANN: melt temperature, mold temperature, injection speed, packing pressure, packing time, and cooling time. As output parameters, the mass, nominal diameter, and height of the injection-molded product were set. Two learning structures were applied to the ANN. The single-task learning, in which all output parameters are learned in correlation with each other, and the multi-task learning structure in which each output parameters is individually learned according to the characteristics, were constructed. As a result of constructing an artificial neural network with two learning structures and evaluating the prediction performance, it was confirmed that the predicted value of the ANN to which the multi-task learning structure was applied had a low RMSE compared with the single-task learning structure. In addition, when comparing the quality specifications of injection molded products with the prediction values of the ANN, it was confirmed that the ANN of the multi-task learning structure satisfies the quality specifications for all of the mass, diameter, and height.

• Design & Manufacturing
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• 제17권2호
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• pp.62-69
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• 2023

In this study, we conducted a study on the optimization of injection molding conditions to minimize deformation of plastic product. The charging management system housing of the vehicle was selected as the research subject. Melting temperature, cooling temperature, packing time, and packing pressure were selected as the main factors expected to affect the deformation of molded products. Each main factor was divided into 5 levels. Optimization of injection molding conditions to minimize deformation was performed using the Taguchi Method. We performed an analysis of variance (ANOVA) to identify significant factors affecting the deformation of plastic product. In order to select injection molding conditions that minimize deformation of plastic products, injection molding analysis was additionally performed for insignificant factors. We then compared the deformation of the molded part before and after optimization. As a result of comparing the injection analysis results of the basic conditions and the injection analysis results of the optimal conditions, it was confirmed that the amount of deformation after optimization was improved by about 10.9%.

• Design & Manufacturing
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• 제18권2호
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• pp.41-50
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• 2024

In this study, experimental design methods were used to derive optimal process conditions for improving the thickness uniformity of a 0.40 mm, 3.5 inch light guide panel. Process mapping and expert group analysis were used to identify factors that influence the thickness of injection molded products. The key factors identified were mold temperature, mold temperature, injection speed, packing pressure, packing time, clamp force, and flash time. Considering the resin manufacturer's recommended process conditions and the process conditions for similar light guide plates, a three-level range was selected for the identified influencing factors. L27 orthogonal array process conditions were generated using the Taguchi method. Injection molding was performed using these L27 orthogonal array to mold the 3.5 inch light guide plates. Thickness measurements were then taken, and the results were analyzed using the signal-to-noise ratio to maximize the CpK value, leading to the determination of the optimal process conditions. The thickness uniformity of the product was analyzed by applying the derived optimum process conditions. The results showed a 97.5% improvement in the Cpk value of 3.22 compared to the process conditions used for similar light guide plates.