• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.940-941
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• 2015

LCD (liquid crystal display) industry is needed to goods of high reliability and is interested in products without harmful material. In this experiment, we made the LED backlight unit for Automotive-navigation. And for making this backlight unit we used to eight side emitting type white LEDs with 1W high power of the lumileds company. We could know that this backlight unit releases to 6500 nit in 14W power consumption and start up voltage time is under the15ms in the ambient temperature $-20^{\circ}C$.

• Journal of Environmental Health Sciences
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• v.3 no.1
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• pp.27-44
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• 1976

This study was carried out to evaluate the harmful factors in working environments and to investigate the labor productivity after improvement of environments, surveying 93 industrial establishments of 10 industries located in Youngdeungpo industrial area in Seoul. The results obtained were as follows: 1) The highest noise level of 125dB(A) was indicated at the rolling process of transport equipment manufacturing industry. 2) The best illumination level was shown in precise machinery industry and the worst was indicated in rubber products, metallic products and transport equipment manufacturing industries. 3) Thermal conditions were above threshold limit value (TLV) at more than two processes of all industries except printing industry. 4) The highest dust concentration was determined in textile and wearing manufacturing industry. 5) Organic solvents were detected at 52 processes in 93 industrial establishments and 33 processes of them showed higher than TLV. The results about harmful chemicals were as follows: a) sulfur dioxide ($SO_2$)was determined higher than TLV on welding process of metallic product manufacturing industry and heat treatment process of transport equipment manufacturing industry. b) Carbon monoxide (CO) concentration was 700ppm at heat treatment process of transport equipment manufacturing industry, indicating 14 times of TLV. c) vinylchloride concentration in the air of PVC raw material mixing process and PVC preparation process of chemical product manufacturing industry was determined higher than TLV. d) Hydrochloride (HCl) concentration in the air of wire expanding process of transport equipment manufacturing industry was determined higher than TLV. 7) Higher values of lead concentration than TLV were determined at lead welding metallic product manufacturing industry and type planting process of process of printing industry, $1.8mg/m^3$ and $0.3mg/m^3$ respectively. 9) 22, 968 of 52, 855 workers (i.e. 43.5%) in 93 industries were exposed to various harmful agents. 10) It was found that the improvement of illumination in electric apparatus manufacturing industry (from 20~40 lux to 420 lux) resulted in an increase in productivity of 6.5% per capita and a decrease in faulty products of 19%. 11) Improvement of environments using local exhaust ventilation system resulted in a decrease of harmful substances lower than TLV and an increase in productivity of 11.4%. 12) Improvement of shovelling tools based on ergonomics resulted in a reduction in energy expenditure of 25.3% and an increase in productivity of 32.2% per capita.

• The Korean Journal of Community Living Science
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• v.18 no.1
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• pp.39-53
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• 2007

The purpose of this study was to determine the characteristics of an experimental protective clothing material with regard to comfort and isolation from the hazardous heavy metals produced in municipal waste incineration. An analysis was conducted on the total concentrations of heavy metals in some parts such as surface, middle layer, and interior for the treated fabric, and the untreated one, and working clothes. We conclude that the processed fabric with charcoal for working clothes showed the least exposure to heavy metals of the three. Working clothes worn by workers during waste incineration were much more contaminated than the untreated and treated materials. The material of working clothes could be chosen according to the function with regard to its original chemical characteristics, which are the proper results of the dyeing process. The processed fabric material has high degrees of moisture regain, thermal insulation, water vapor penetration, and antibacterial function; consequently, it is much more comfortable to wear. The fabric material proposed in this research contributed much more to blocking heavy metal concentrations (such as Cd, Pb, Cu, Cr, Zn, Mn) than did the fabric of working clothes at present. Consequently, we strongly suggest that the material of working clothes be upgraded by adopting the above-mentioned charcoal-processed fabric. Materials of working clothes must be improved to increase comfort and prevent harmful gas, flying dust, and heavy metals from permeating the fabrics.

• Transactions of Materials Processing
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• v.30 no.4
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• pp.165-171
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• 2021

This study was conducted on the manufacturing method of high-strength aluminum bolts. We obtained the displacement-load information by tensile test of the Al 6056 raw material and the T6 heat-treated material and calculated the precise flow stress and fracture limit using repetitive finite element analysis for before and after heat treatment. We designed a multi-stage forging process for T6 heat-treated material, and calculated that the accumulated damage value does not exceed fracture limits by finite element method. We produced the prototype forgings without any harmful defects such as cracks and folding occurring. Bolts made of T6 heat treated material show 9.6%higher tensile strength than T6 heat treated material after wire drawing.

• Korean Journal of Environmental Biology
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• v.34 no.2
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• pp.91-96
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• 2016

This study presents the potentiality of harmful algal bloom (HAB) control through the zooplankton, Daphnia magna. In case of co-cultivated D. magna with cyanobacteriums (Microcystis aeruginosa, Anabaena variabilis, and Limnothrix planctonica), the D. magna showed the $80.2{\pm}4.2%$, $39.7{\pm}4.0%$, and $25.9{\pm}10.9%$ of control efficiency for M. aeruginosa, A. variabilis and L. planctonica, respectively. Furthermore, algal control was investigated by using supernatant including metabolite/secretion of D. magna. The algal control efficiencies of supernatant were recorded as $24.9{\pm}9.9%$ and $8.9{\pm}4.0%$ for M. aeruginosa and A. variabilis, respectively. From the results of present study, it may be possible to provide a feasible way for development of eco-friendly HAB control methods.

• Journal of the Korean Society of Safety
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• v.21 no.2 s.74
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• pp.150-157
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• 2006

Sick Building Syndrome (SBS) is an illness symptom such as irritation of eyes, skin eruption and vomit ing in newly constructed buildings. It is mainly due to the harmful gases from the materials installed in building such as Volatile Organic Compounds (VOCs), Semivolatile Organic Compounds (SVOCs), floating bacteria, fungi, fungal spores and viruses, human bioeffluents in many modem buildings. The general ways to improve the Indoor Air Quality (IAQ) are ventilating, utilizing eco-material without harmful gases and reducing or removing harmful gases through additional treatment to the building materials. This study aimed to improve the Indoor Air Quality(IAQ) by applying surface coating on the building materials and to make safe living environments through the analysis of air quality before and after surface coating treatment in buildings.

• Journal of the Korean Applied Science and Technology
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• v.14 no.1
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• pp.45-52
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• 1997

It is the problem point of stability for this study to produce cosmetics and to occur in the circulation process, and specially in a case of alcoholic toilet water the precipitation materials to float on content materials has study on the solubility of perfume, and it has practiced in order to examine the problem point whether the raw materials of plastic vessel is or not harmful in content materials. In testing result, A study on stability of alcoholic toilet water is above all the precipitation materials which floats in content materials, and It is appeared by combination ratio to the raw materials of perfume, ethanol, solubilizer and refining water etcs, and in second the alkali degree which has gushed out of glass vessel can understand the thing that the change of PH is largely increased following to the passage of time, and in third the harmful component of content materials out of raw material in plastics vessel must certainly consider a stability and a safety in quality control of products.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.541-544
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• 2004

Change is doing our life more conveniently and abundantly by knowledge information society, but side effect and that is happening considerable and gropes solution in reply that did not expect in advance is urgent real condition. It can be called one of representative dysfunction of information-oriented society that human nature is revealed in open state to great many objectionable material and poisonous information such as violence kind that teenagerses who do not grow are gotten abroad through Information network system yet. So, to solve these fallacy, word-weighting process, where several harmful words which can be optained in internet site are discriminance and weighted, is utilized by using AC machine. At the result, the isolation rate of harmful site rose up to 90%, which means this process is greatly efficient.

• Journal of Yeungnam Medical Science
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• v.36 no.1
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• pp.20-25
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• 2019

Background: The aim of this study was to evaluate the awareness of occupational hazards and personal protective equipment use among dental hygienists (DHs). Methods: A total of 271 self-administered questionnaires were obtained from 280 DHs working at dental hospitals or clinics in Daegu and Gyeongsangbuk-do, Korea. Results: The occupational hazards included work involving dust (94.1%), volatile substances (86.0%), noise (97.0%), and light-curing units (96.7%). The proportion of dental hygiene tasks that participants perceived as harmful were 42.4%, 51.7%, 9.2%, and 31.4% in the same order as above. The proportion of participants who used dust-proof masks during work involving dust was 1.1%. Those who wore gas-proof masks and gloves for work using volatile substances were 0.7% and 31.2%, respectively. Participants who used goggles for work involving light-curing units were 31.0%. None of the participants used ear plugs for work involving noise. A total of 22.9% of the participants recognized the Material Safety Data Sheet, while 79.7% had never been educated about harmful work environments. Conclusion: When compared to exposure status and perception of occupational hazards, the level of protective equipment use was very low. Extra measures to increase DHs' use of personal protective equipment are necessary.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.17 no.1
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• pp.63-70
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• 2007

This study investigated the current management staus of chemical substance information on Material Safety Data Sheets(MSDS) and Chemical Information Cards(CIC) provided by Korea Occupational Safety & Health Agency(KOSHA) and also researched the kind and the characteristics of chemical substance information provided in other organizations. MSDS DB in Korean provided on KOSHANET(which is Kosha website) is 50,802 in total, among whom are single chemical substances with 31,870 kinds(18,932%) and are mixed chemical substances with 31,870 kinds(62.7%). The number of visiting MSDS DB on KOSHANET for the search of chemicals was 2,049,806. The number has increased each year. The CIC provided for workplaces is all 542 kinds : 14 harmful substances subject to permission, 168 harmful substances subject to management, 360 KOEL(Korean Occupational Exposure Limits) establishment substances. MSDS internationally provided by organizations producing MSDS DB was written with 16 sections, which is suitable for the writing basis of American Standards Institute(ANSI) and International Organization for Standardization(ISO) and provided chemical substance information on more than 100,000 kinds in most organizations.