• 대한임베디드공학회논문지
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• 제9권1호
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• pp.11-16
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• 2014

When it comes to develop flight simulator, HAT (Height Above Terrain) is required to provide altitude information to the pilot who learns how to control an airplane in landing and takeoff situation. However, there might be inconsistent problem between real terrain and simulation information since current implementation of HAT simply depends on center of gravity point on the airplane. To overcome mentioned problem, in this paper, we propose how to obtain more accurate altitude information than existing scheme by making use of HAT and HOT (Height Of Terrain) information of landing equipments according to movement of the airplane. Moreover, we demonstrate the accuracy of the proposed scheme through new flight simulator developed through OSG(OpenSceneGraph) by taking example of terrain information for domestic airport.

• 한국의류학회지
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• 제28권5호
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• pp.713-722
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• 2004

This study examined the effects of two kinds of functional sun hats through a head-manikin test and a climatic chamber trial for farm workers in summer. Experiment was composed of four conditions. The first condition was the condition without any hat (Control). The second was the condition with a sun hat on the market (Hat A). The third was the condition with a functional sun hat made of reflective fabric (Hat B). The last was the condition with a functional sun hat having a ventilating structure as well as reflective fabric (Hat C). For the subjects in the climatic chamber trials, 12 healthy males volunteered. Air temperature, relative humidity and globe temperature in the chamber was maintained at $33{\pm}0.5^{\circ}C,\;65{\pm}5%RH\;and\;39{\pm}1^{\circ}C\;(WBGT\;33^{\circ}C)$. Subjects did a simulated red pepper-work (50-min work and 10-min rest, twice repetition) for 120 min. As the result of head-manikin test, the surface temperature on middle of back-neck was the lowest in Hat B of four conditions and the surface temperature on top of head was the lowest in Hat C. As the result of climatic chamber trials, there were apparent differences between with (Hat A, Hat B, Hat C) and without a sun hat (Control). In rectal temperature ($T_{re}$), mean skin temperature ($\={T}_{sk}$), heart rate (HR), total sweat rate (TSR), The physiological heat strain was less in the condition with hats than in the condition without a sun hat. As the increasing rate in Tre, Hat B is the most effective hat for alleviation heat strain. As the subjective responses, Hat B was the most effective hat for thermal comfort even though the difference was not significant. Hat C was less effective than Hat B and the reason might be the increase of weight due to inserting the ventilating structure.

• 한국의류학회지
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• 제26권1호
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• pp.74-82
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• 2002

본 연구에서는 서열환경하에서의 안전모 착용과 관련된 생리학적 온열반응을 조사하고 아울러 일반적인 안전모에 통풍을 목적으로 구멍을 뚫어 놓은 안전모가 작업시 체열방산, 체온의 항상성과 같은 생리반응에 어떠한 영향을 미치는지에 대한 검토를 실시하고자 성인 남자 5명을 대상으로 착용실험을 실시하였다. 구멍이 없는 일반적인 형태의 무공 작업 안전모와 통기를 목적으로 구멍을 뚫어 놓은 유공 작업 안전모를 대조군으로 하여, 온도 30$\pm$1$^{\circ}C$, 습도 55$\pm$10%R.H의 인공기후실에서 휴식과 운동을 되풀이하는 총70분간의 실험을 실시하였다. 그 결과를 요약하면 다음과 같다. 1. 직장온과 심박수는 유공안전모 착용시가 무공안전모 착용시 보다 유의하게 낮게 나타났으며, 체열평형과 관련하여 신체기능의 항상성을 유지하는 데에 유공안전모를 착용하는 것이 더 효율적임을 알 수 있었다. 2.각 부위의 피부온과 평균 피부온은 유공안전모 착용시가 무공안전모 착용시보다 유의하게 낮았는데 특히 발한이 다른 부위보다 먼저 시작되는 이마에서 더욱 두드러지게 나타났다. 이는 안전모 착용으로 체온이 상승되어 피부온과 평균 피부온의 상승으로 이어지는 과정에서 유공안전모 착용시 가 무공안전모 착용시보다는 더 유리하다는 것을 알수 있었다. 3. 혈압은 전 구간에 걸쳐 유공안전모 착용시가 무공 안전모 착용시 보다 낮게 나타났다. 유공안전모 착용시가 무공안전모 착용시 보다 혈액을 통해 전달되는 체열의 상승이 억제되고 피부온과 심박수의 상승이 억제되는 것을 알수 있었는데 이것이 곧 혈압의 과다상승 방지와 인체부담의 경감으로 연결되었다고 사료된다. 4. 발한량은 유공안전모 착용시가 무공안전모 착용시보다 낮은 값을 나타내 보였다. 운동으로 인해 높아진 머리부분의 온도는 통풍을 목적으로 구멍을 뚫어 놓은 유공안전모를 착용했을 때 통기구멍으로 공기가 순환되어 온도가 과도하게 상승하는 것이 방지된다. 따라서 서열환경하에서의 체온상승이 억제됨에 따라 낮은 발한량을 나타내 보였다. 안전모내의 기후에서 유공안전모 착용시가 무공안전모 착용시보다 유의하게 더 낮은 온도를 나타내었고, 안전모내 습도는 운동시에 유공안전모 착용시가 무공안전모 착용시보다 다소 낮은 경향을 보였다. 통기를 목적으로 구멍을 뚫어 놓은 유공안전모를 착용함으로 인해 모자내의 더운 공기가 외부와 순환되어 무공안전모 착용시 보다는 온도가 낮게 나타났고 땀이 유공안전모의 구멍을 통해 증발을 일으켜 과도하게 습해지는 것을 방지 할 수 있었다. 5. 주관적 감각으로 온냉감, 습윤감, 쾌적감, 피로감을 측정하였는데 유공안전모 착용시가 무공안전모 착용시보다 더 낮은 주관적 감각 수치를 나타내어 착용감이 더 좋았음을 알 수 있었다. 또한 근력측정에서 무공안전모 착용시가 유공안전모 착용시 보다 평가 수치 가 낮게 나타나 더 피로한 것을 알수 있다. 이상의 결과에서 통기를 목적으로 구멍을 뚫어놓은 유공작업안전모가 심부온, 피부온, 혈압, 심박수, 발한량, 모자내 기후 등의 인체생리반응을 고려해 볼 때 더 바람직한 작업 안전모 형태라는 것을 알 수 있었다. 종래의 작업과 관련한 피복연구에서 작업복, 장갑, 신발에 대하여는 생리학적 연구가 이루어졌으나, 안전모에 관한 연구에서는 생리학적인 부분을 고려하지 않고 단지 안전 보호측면에서의 연구가 이루어졌을 뿐이었다. 따라서 서열환경하에서 머리부분의 쾌적성을 고려한 다양한 작업 안전모에 대한 계속적인 연구와 개발이 이루어진다면 물리적 측면에서 작업 안전을 만족시킬 뿐만 아니라 생리적 측면에서 체열 평형을 도모하여 작업 능률의 향상을 가져올 것이다.

• 한국식품영양학회지
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• 제7권4호
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• pp.297-306
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• 1994

This experiment was carried out to investigate the healing loss and the heavy metal residues such as copper, zinc, manganese, cadmium and lead In porcine visceras by inductively coupled argon plasma spectrometer(ICP), and to probe changes when porcine visceras were boiling In water treatment(BWT), heating in autoclave treatment (HAT) and heating In oil treatment (HOT) . The range of heating loss on porcine viscera were BWT(23.11∼34.53%) , HAT(18.48∼28.00%) and HOT(14.20∼25.22%)and the heart tissue were higher and liver were lower than those of the other tissues. The total value of heavy metal residues in large intestine, small intestine, heart, kidney, liver and stomach tissue were 11.298${\pm}$5.302 ppm, 27.825${\pm}$8. 177 ppm, 16.756${\pm}$6.334 ppm 21.107${\pm}$6.057 ppm, 25.369 ${\pm}$ 10.164 ppm and 12.611 ${\pm}$5.513 ppm, respectively. Heavy metal residues in porcine visceras tended to decrease according to heating methods and the variety viscera, and the change of total heavy metal residues on BWT, HAT and HOT were 4.16∼32.57%, 12.01∼28.09% and 9.60∼25.76%, respectively. The decrease of lead element of mean value were 21.76% and copper, zinc, manganese and cadmium element were 18.00∼ 18.16%. The change of heavy metal residues were not significant in the porcine visceras(P>0.05), and the these were significantly correlated among the three heating method(P < 0.05).

• 소성∙가공
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• 제20권6호
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• pp.427-431
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• 2011

In general, hot stamped component is trimmed by costly and time consuming laser cutting when the material strength is over 1,500MPa. The aim of this work was to demonstrate that the trimming die life is improved and the trimming load is decreased by lowering the strength of the region to be trimmed. The model employed in this study was a hat shape, similar to the cross section of many hot stamped products. FE-analysis of hot stamping process was performed to evaluate the effect of tool shape on cooling rate at the area to be trimmed. The best tool shape was thus identified, which created slower cooling and lower hardness at the region to be trimmed. The wear at the cutting tool edge was also reduced.

• 소성∙가공
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• 제32권3호
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• pp.160-165
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• 2023

As the supply of eco-friendly vehicles increases, the application rate of hot stamping components is rising to reduce vehicle weight and improve safety. Although Al-Si coated steel sheets are commonly used in hot stamping processes, their manufacturing costs are elevated due to process patents and royalties. Various hot stamping studies have been conducted to reduce these production costs. In this study, we derived a process control method for suppressing the oxide layer of hot stamping parts using uncoated boron steel sheets. Firstly, hat-shaped parts were hot stamped under atmospheric conditions to analyze the tendency of oxide layer formation by location. Then, the Gleeble system was used to observe oxide layer formation based on oxygen content under various atmospheric conditions. Finally, the oxide layer thickness was quantitatively measured using SEM images.

• 소성∙가공
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• 제26권2호
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• pp.101-107
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• 2017

Aluminum alloys are widely used in automotive industry because of their high strength-to-density ratio and excellent corrosion resistance. However, conventional cold stamping of aluminum alloys leads to low formability and excessive spring-back. To overcome these problems, Hot Forming Quenching (HFQ) is applied to manufacture automotive part using aluminum alloy. The purpose of this study is to investigate effect of forming temperature on spring-back in HFQ of T6 heat treated AA6061 sheet. In this study, hat shape forming test was adopted to evaluate spring-back characteristics according to various forming temperatures. In additions, the test was also performed with warm forming conditions in comparison with dimensional accuracy of HFQed part. The experimental results showed that dimensional accuracy of HFQed part was superior to warm formed part and amount of spring-back was decreased as forming temperature rise.

• 열처리공학회지
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• 제17권2호
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• pp.73-77
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• 2004

The efforts which increase the strength of the auto-body structure and decrease its weight lead to develop a new concept of part production systems, such as Post-Form Strengthening by induction heat treatment. In this study, several cold and hot-rolled sheet steels were used to find out optimum induction heat treatment conditions. After induction heat treatment, strength of heat-treated sheet steels was increased significantly compared with that of as-rolled steels. From these results, auto-body structure which has more light and safe has been made by using this induction hardening method.

• Asian-Australasian Journal of Animal Sciences
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• 제8권3호
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• pp.255-261
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• 1995

This paper presents results from a study of the effects of age and sex on body and carcass composition of different goat genotypes. A completely randomized $3{\times}3{\times}2$ factorial design was used. Factors were genotype (Thai Native; TN, $50%TN{\times}50%$ Anglo-Nubian (AN) and $25%TN{\times}75%AN$ goats), age ($206{\pm}8$, $349{\pm}9$ and $428{\pm}8days$ or 6.9, 11.6 and 14.3 months, respectively) and sex (male and female). It was shown that TN kids had significantly higher (p < 0.05) hind percentage (7.9%) compared with $50%TN{\times}50% AN$ (7.2%) and $25%TN{\times}75%AN$ (7.1 %) kids. TN kids had a significantly (p < 0.05) higher heart percentage (0.44%) than that of $25%TN{\times}75%AN$ kids (0.38%). However, there was no significant difference in heart percentage between TN and $50%TN{\times}50%AN$ and between $50% TN{\times}50%AN$ and $25%TN{\times}75%AN$ kids. TN and $50%TN{\times}50%AN$ kids had significantly higher (p < 0.05) carcass muscle content (63.1 and 63.7%, respectively) than did $25%TN{\times}75%AN$ kids (59.9%). Kids at 6.9 months of age had significantly higher percentages of hide, feet, intestinal tract, liver, heart, kidneys and carcass bone than those of kids at 11.6 and 14.3 months of age. There were no significant differences in these characteristics between kids at 11.6 and 14.3 months of age. However, kids at 11.6 and 14.3 months of age had significantly higher percentages of omental fat, dressing carcass, muscle, total fat (subcutaneous + intermuscular + kidney and pelvic fat), muscle to bone ratios (MBR), and muscle plus fat to bone ratios (MFBR) than those of kids at 6.9 months. Males had significantly higher gut contents, but lower percentages of liver, omental fat and heart. Prediction equations were developed relating empty body weight (EBW) to hot carcass weight and some dissectible carcass fractions.

• 한국의류학회지
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• 제31권11호
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• pp.1520-1529
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• 2007

Workers on construction sites are exposed to multiple and varied threats. Of those, climatic factors such as high/low air temperatures and high/low humidity have a bad mental and physical health effect on workers. Especially, work in hot environment has a tendency to cause fatigue, reduce productivity and increase the incidence of accident. So, the purpose of this research was to understand working clothes and working environment of workers at a construction site in summer. The depth interview was performed by 45 workers of 4 different construction sites and the results were as follows. Workers wore average 4 items as clothing(upper, lower) and average 5 items as personal protective equipments(PPEs). They answered "head" is the hottest body area and must be protected during working. This means the necessity of development in safety hat. In addition, it should be developed working clothes and gaiters for alleviating heat stress and safety shoes for diminishing weight. It is expected that this research plays basic and important rolls to develop PPEs for reducing the heat stress of construction workers.