• Title/Summary/Keyword: Wear rate

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Smart Helmet for Vital Sign-Based Heatstroke Detection Using Support Vector Machine (SVM 이용한 다중 생체신호기반 온열질환 감지 스마트 안전모 개발)

  • Jaemin, Jang;Kang-Ho, Lee;Subin, Joo;Ohwon, Kwon;Hak, Yi;Dongkyu, Lee
    • Journal of Sensor Science and Technology
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    • v.31 no.6
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    • pp.433-440
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    • 2022
  • Recently, owing to global warming, average summer temperatures are increasing and the number of hot days is increasing is increasing, which leads to an increase in heat stroke. In particular, outdoor workers directly exposed to the heat are at higher risk of heat stroke; therefore, preventing heat-related illnesses and managing safety have become important. Although various wearable devices have been developed to prevent heat stroke for outdoor workers, applying various sensors to the safety helmets that workers must wear is an excellent alternative. In this study, we developed a smart helmet that measures various vital signs of the wearer such as body temperature, heart rate, and sweat rate; external environmental signals such as temperature and humidity; and movement signals of the wearer such as roll and pitch angles. The smart helmet can acquire the various data by connecting with a smartphone application. Environmental data can check the status of heat wave advisory, and the individual vital signs can monitor the health of workers. In addition, we developed an algorithm that classifies the risk of heat-related illness as normal and abnormal by inputting a set of vital signs of the wearer using a support vector machine technique, which is a machine learning technique that allows for rapid binary classification with high reliability. Furthermore, the classified results suggest that the safety manager can supervise the prevention of heat stroke by receiving feedback from the control system.

Slacks pattern development for the female adolescents with lower-body obesity using virtual simulation system (가상착의 시스템을 활용한 하체 비만 여자 청소년의 슬랙스원형 설계)

  • Jiyoung Lim
    • The Research Journal of the Costume Culture
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    • v.31 no.6
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    • pp.793-805
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    • 2023
  • This study analyzes the body shapes of lower-body obese female adolescents and proposes a slacks pattern suitable for their body type. Lower-body obesity is a prevalent type of teenage obesity, and our proposals aim to improve consumer satisfaction in ready-to-wear clothes across this demographic. We first observe characteristics of obese lower bodies, noting significantly above-average thigh and hip circumference. These figures indicate a high degree of curvature in obese lower bodies, along with a large drop value. Leveraging this data, we develop a novel slacks pattern using 3D avatars in a virtual simulation system. The formulas for the main areas of the pattern are as follows: front waist girth W/4+0.75cm+0.5cm, back waist girth W/4+0.5cm-0.5cm, front hip girth H/4+1.25cm-0.5cm, back hip girth H/4+2cm+0.5cm, front crotch extension H/16+0.5cm, back crotch extension H/8+1cm. Results from appearance evaluations show that this pattern minimizes strain rate on the waist and hips, and its average score is significantly higher than that of an alternative pattern that was also evaluated. The minimized strain rate and high average score indicate that our pattern assigns a sufficient amount of space to the appropriate areas. Based on these results, we expect our research to inform slacks pattern development and production for obese consumers of all types.

Evaluation of Microstructure and Mechanical Properties according to Cooling Method after Hot Forging of High Manganese Steel Flange (고망간강 플랜지의 열간 단조 후 냉각방법에 따른 미세조직 및 기계적 특성 평가)

  • Minha Park;Gang Ho Lee;Byung Jun Kim;Byoungkoo Kim
    • Korean Journal of Materials Research
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    • v.34 no.1
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    • pp.44-54
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    • 2024
  • High-Manganese (Mn) austenitic steel, with over 24 wt% Mn content, offers outstanding mechanical properties in cryogenic settings, making it a potential replacement for existing cryogenic materials. This high manganese steel exhibits high strength, ductility, and wear resistance, making it promising for applications like LNG tanks, flanges, and valves. To operate in cryogenic environments, hot forging and heat treatment processes are vital, especially in flange production. The cooling rate during high-temperature cooling after hot forging plays a critical role in influencing the microstructure and mechanical properties of high manganese steel. The rate at which cooling occurs during this process influences the size of the grains and the distribution of manganese and consequently has an impact on mechanical properties. This study assessed the microstructure and mechanical properties based on different cooling rates during the hot forging of High-Mn steel flanges. Comparing air and water cooling after hot forging, followed by heat treatment, revealed notable differences in grain size. These differences directly impacted mechanical properties such as tensile strength, hardness, and Charpy impact property. Understanding these effects is crucial for optimizing the performance and reliability of High-Mn steel in cryogenic applications.

Performance Evaluation of Quality-Improved Recycled Aggregate Using Ultrasonic Wave and Chemical Neutralization Reaction (초음파 세척 및 화학적 중화반응을 이용한 품질 개선된 순환골재의 성능 평가)

  • Jay Jang-Ho Kim;Young-Jun You
    • Journal of Korean Society of Disaster and Security
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    • v.17 no.1
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    • pp.27-35
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    • 2024
  • This paper presents experimental research results to evaluate the applicability of chemical neutralization reaction and ultrasonic wave to remove cement paste and mortar attached to the surface of recycled aggregate. In order to derive optimal ultrasonic cleaning efficiency and chemical neutralization reaction, experiments were conducted using variables such as ultrasonic frequency and type of chemical solution. As a result, the optimal frequency was found to be 24 kHz, and immersion in a 15% hydrochloric acid solution for 30 minutes of stimulation showed the highest efficiency. In addition, the specific gravity, absorption rate, and wear rate of the quality-improved recycled coarse aggregate were similar to those of general aggregate and were found to satisfy all KS F 2527 standards. Therefore, it is believed that the recycled aggregate whose quality has been improved through the method proposed in this study can be used for concrete.

A Study on Improving the Performance of Shale for Application of Aggregate for Concrete (콘크리트용 골재활용을 위한 셰일 골재의 성능개선에 관한 연구)

  • Lee, Seung-Han;Jung, Yong-Wook;Jang, Seok-Soo;Yeo, In-Dong;Choi, Jong-Oh
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.11
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    • pp.5915-5922
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    • 2013
  • In this study, with the aim of improving the performance of shale to allow for its use as coarse aggregate for concrete, we coated shale aggregates with water repellents and polymers and evaluated their physical properties such as density, water absorption rate, wear rate, and stability depending on the coating method. In addition, the effects of the performance improvement were evaluated by assessing the properties of fresh concrete produced by varying the shale substitution ratio, as well as the compressive strength, flexural strength, and freeze-thaw resistance according to curing ages. The test results revealed that the absolute dry densities of all coated aggregates satisfied the standard density for coarse aggregates for concrete(>$2.50g/cm^3$),and the absorption rate of the shale aggregate coated with water repellent decreased by about 50% compared with that of uncoated shale. The wear rate of the polymer-coated shale decreased by up to 13.0% compared with that of uncoated shale. All coated aggregates satisfied the stability standard for coarse aggregates for concrete(${\leq}12$). The water repellent-induced performance improvement decreased the shale aggregates' slump by about 20~30mm compared with that of the uncoated shale aggregates, and the air content of the repellent-coated shale aggregate increased by up to 0.9% compared with that of the uncoated shale aggregate. The compressive strength of the polymer-coated shale aggregates at a curing age of 28 days was RS(F) 95.7% and BS(F) 90.0%, and the flexural strength was RS(F) 98.0 % and BS(F) 92.0% of the corresponding values of concretes produced using plain aggregates. Furthermore, the concrete using polymer-coated shale aggregates showed a dynamic modulus of elasticity of RS(F) 91% and BS(F) 88% after 300 freeze-thaw cycles, thus demonstrating improved freeze-thaw durability.

Assessment of Wicking and Fast Dry Properties According to Moisture Transport Measurement Method of Knit and Woven Fabrics for Garment (의류소재용 직·편물의 수분이동 특성 측정 방법에 따른 흡한속건성 평가)

  • Kim, Hyun-ah;Kim, Seung-jin
    • Science of Emotion and Sensibility
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    • v.20 no.2
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    • pp.117-126
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    • 2017
  • In this study, moisture transport characteristics for the woven and knitted fabrics made of 8 kinds of fiber materials using MMT (moisture management tester) were measured and discussed with the Bireck bt MMT and water evaporating rate (WER) measuring methods, which are vertical moisture transport methods. In addition, the drying property by MMT of the eight kinds of specimens was compared and discussed with the results measured by the vertical drying measurement. MMT experimental result which is horizental moisture transport appeared to be similar to the result of the Bireck method, which is the vertical moisture transport experiment. Absortion time measured from drip method of the fabrics made of the bamboo, linen, and cotton/nylon composite fabrics was short and thus they showed best wicking property, which was attributed to the low contact angle on the fabric surface and high porosity of the fabrics due to the staple yarn structure composed of the hydrophilic staple fibers. In drying property of the fabric specimens by MMT, maximum absorption radius of the dry-zone knit and bamboo woven fabrics were the highest and they showed the best drying property, which was a little different result compared with vertical drying measurement method. Half time of the drying rate in the MMT method was highly correlated with the fabric thickness and saturated moisture absortion rate and their regression coefficients were 0.9 and 0.88, respectively. This means that the knitted and woven fabric design technology for retaining good wicking and drying properties of the fabrics with thin fabric thickness is very important for obtaining high functional wear comfort fabrics. In addition, wicking and drying properties of the fabrics made of different fiber materials and with different yarns and fabric structures showed different results according to the measuring methods.

A Study on Hepatitis Infection Risk of Funeral director related to wearing PPE(Personal Protect Equipment) (한국 장례종사자의 개인보호물품 착용에 따른 A형 간염, B형 간염 위험도 및 로지스틱 분석)

  • Hwang, Kyu-Sung;Kim, Jeong-Lae
    • The Journal of the Convergence on Culture Technology
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    • v.3 no.2
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    • pp.15-20
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    • 2017
  • We are investigated about the Hepatitis infection risk of the funeral director related to wearing PPE(Personal Protect Equipment) within Metropolitan, Chungcheong and Gyeongsang regions in Korea. We are classified that the vaccinated group was classified as low risk group and the non-vaccinated group was classified as high risk group. And we are analyzed the risk rate of infection based on whether or not to wear PPE(personal protective equipment) among high-risk groups. The result is as follows. The mask wearing rate of high-risk group about HAV(hepatitis A virus) is three times lower than that of low-risk group. The surgical glove wearing rate of high-risk group about HBV(hepatitis B virus) is twice lower than that of low-risk group. The surgical glove and mask not wearing rate among the high-risk group observe that potential infection risk was high 4.23 times and 3.5 times, respectively. We are concluded that increasing the risk of potential infection risks from the funeral director could result in increased risk of infection to national public health, including the bereaved family. We are suggested that the funeral director must be bound to vaccinate against hepatitis and make PPE mandatory. It is deemed necessary for the government to develop policies to promote personal health and national health care.

The Actual Wearing Conditions and Preferred Design of Tailored Jackets for Obese Women in Their 20s and 30s (20~30대 비만여성의 테일러드 재킷 착용실태 및 선호디자인)

  • Oh, Young-Soon;Lee, Jeong-Ran
    • Journal of the Korean Society of Clothing and Textiles
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    • v.34 no.9
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    • pp.1479-1490
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    • 2010
  • This study provides basic data for the development of jacket patterns which reflect designs corresponding to the body shape features and preferences of obese women in their 20s and 30s by understanding problems they may encounter in wearing a ready-made jacket by researching the reality of ready-made tailored jacket wearing and their design preferences. A survey was conducted by sampling 82 obese women (over $25kg/m^2$ BMI) between the ages of 20 to 39. The details of the survey consists of general information, interest rate and importance rate on clothes, reality of wearing and purchasing jackets, measurement fits per each part, and preferred designs. SPSS 14.0 was used to analyze the data. The results showed that 76.8% of obese women wore their jackets less than 5 times a month. Those in the 20s wore the jackets more frequently than those in the 30s. The reasons for not wearing jackets frequently included uncomfortableness in activities and unavailability of the correct size. A total of 55% of the total preferred the fitting to be relatively smaller than the body size or tightly fitting. Although in the past, there was a tendency to wear a loose fit to cover the body shape, currently even obese body shapes avoided the loose fit as the tight fit is the trend. In terms of the satisfaction rate for the measurements per each part of jackets, there was a low satisfaction rate for most of the items. For the circumference items such as waist length and chest size, people responded that they were too small and for the length of items such as the length of jacket and sleeve length, people responded that they were too long. This was because the readymade clothes brands increase the length of items and circumference items in uniform in the same intervals when producing large sizes. Both those in the 20s and the 30s preferred a tight fit. In terms of preferred fabric, a wool/spandex mix was most popular and then cotton/spandex. This shows that they prefer those fabrics which allow an excellent activity while maintaining the exterior well. In addition, they preferred black color with no patterns because they wanted their body size to look reduced and did not want to receive any attention.

Mechanism of aging and prevention (노화의 기전과 예방)

  • Kim, Jay Sik
    • IMMUNE NETWORK
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    • v.1 no.2
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    • pp.104-108
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    • 2001
  • Aging is a senescence and defined as a normal physiologic and structural alterations in almost all organ systems with age. As Leonard Hayflick, one of the first gerontologists to propose a theory of biologic aging, indicated that a theory of aging or longevity satisfies the changes of above conditions to be universal, progressive, intrinsic and deleterious. Although a number of theories have been proposed, it is now clear that cell aging (cell senescence) is multifactorial. No single mechanism can account for the many varied manifestations of biological aging. Many theories have been proposed in attempt to understand and explain the process of aging. Aging is effected in individual by genetic factors, diet, social conditions, and the occurrence of age-related diseases as diabetes, hypertension, and arthritis. It involves an endogenous molecular program of cellular senescence as well as continuous exposure throughout life to adverse exogenous influences, leading to progressive infringement on the cell's survivability so called wear and tear. So we could say the basic mechanism of aging depends on the irreversible and universal processes at cellular and molecular level. The immediate cause of these changes is probably an interference in the function of cell's macromolecules-DNA, RNA, and cell proteins-and in the flow of information between these macromolecules. The crucial questions, unanswered at present, concerns what causes these changes in truth. Common theories of aging are able to classify as followings for the easy comprehension. 1. Biological, 1) molecular theories - a. error theory, b. programmed aging theory, c. somatic mutation theory, d. transcription theory, e. run-out-of program theory, 2) cellular theories - a. wear and tear theory, b. cross-link theory, c. clinker theory, d. free radical theory, e. waste product theory, 3) system level theory-a. immunologic/autoimmune theory, 4) others - a. telomere theory, b. rate of living theory, c. stress theory, etc. Prevention of aging is theoretically depending on the cause or theory of aging. However no single theory is available and no definite method of delaying the aging process is possible by this moment. The most popular action is anti-oxidant therapy using vitamin E and C, melatonin and DHEA, etc. Another proposal for the reverse of life-span is TCP-17 and IL-16 administration from the mouse bone marrow B cell line study for the immunoglobulin VDJ rearrangement with RAG-1 and RAG-2. Recently conclusional suggestion for the extending of maximum life-span thought to be the calory restriction.

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Research on the Working Environment and Personal Protective Equipment of Korean Native Cattle Raising Farmers (한우 사육자 작업환경 및 작업복과 보호구 착용 실태 분석)

  • Kim, Insoo;Lee, Kyung-Suk;Chae, Hye-Seon;Kim, Kyungsu;Choi, Dong-Phil;Kim, Hyo-Cher
    • The Korean Journal of Community Living Science
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    • v.27 no.4
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    • pp.891-906
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    • 2016
  • This study examined the working site environment of Korean native cattle raising farmers and their actual condition of wearing personal protective equipment as part of preventing disasters during agricultural work. To this end, 160 Korean cattle raising farmers were surveyed and a site visit was performed on 10 farms. According to an examination of the cattle breeding environment, the major harmful factors were in the following order: fine dust (12.8%), organic feed dust (10.3%), contact with cattle (9.7%), manure (8.2%), germs and viruses (8.1%), harmful gases (7.4), contact with obstacles (6.7), and temperature (6.6%). The current status of the rate of wearing protection was in the order of gloves (20.9%), working hats (19.7%), boots (19.6%), masks (10.9%), protective clothing (8.9%), and specialized working clothing (6.6%). Nevertheless, most Korean cattle raising farmers recognized the risks when they did not wear protective equipment and the need for wearing protectors, but they mostly did not wear personal protective equipment due to a lack of knowledge on the selection of appropriate personal protective equipment and the discomfort they experience when they put on protectors. Even when they put on protective equipment, 38% was inappropriate for the farming work environment. Given the research results, improvements on and the development of specialized working clothing and personal protective equipment to protect farmers from harmful and dangerous materials from the cattle nurturing environment is necessary. Overall, based on the study data, objectified data collection, a determination of the necessary performance elements of personal protective equipment, and R&D will be needed through an on-site current status investigation.