• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.9 no.1
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• pp.56-72
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• 1999

Airborne concentrations of welding fumes in which 13 different metals such as Al, Cd, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Si, Sn, Ti, and Zn were analyzed were measured at 18 factories including automobile assembly and manufactures, steel heavy industries and shipyards. Air samples were collected by personal sampler at each worker's worksite(n=339). Blood levels of Cd, Cu, Fe, Mn, Pb and Zn were also measured from samples taken from 447 welders by atomic absorption spectrometry and compared with control values obtained from 127 non-exposed workers. The results were as follows ; 1. Among various welding types, $CO_2$ welding 70.2 % were widely used, shielded metal arc welding(SMAW) 22.1 % came next, and rest of them were metal inert gas(MIG) welding, submerged arc welding(SAW), spot welding(SPOT) and tungsten inert gas(TIG) welding. 2. Welding fume concentration was $0.92mg/m^3$($0.02{\sim}15.33mg/m^3$) at automobile assembly and manufactures, $4.10mg/m^3$($0.02{\sim}70.75mg/m^3$) at steel heavy industries and $5.59mg/m^3$($0.30{\sim}91.16mg/m^3$) at shipyards, respectively, showing significant difference among industry types. Workers exposed to high concentration of welding fumes above Korean Permissible Exposure Limit(KPEL) amounted to 7.9 % and 12.5 %, in $CO_2$ welding and in SMAW at automobile assembly and manufactures and 62.7 % in $CO_2$ welding, and 12.5 % in SMAW at shipyards, and 66.2 % in $CO_2$ welding and 70.6 % in SMAW at steel heavy industries. 3. Geometric mean of airborne concentration of each metal released from welding fumes was below one 10th of KPEL in all welding types. Percentage of workers, however, exposed to airborne concentration of metals above KPEL amounted to 16.8 % in Mn and 7.6 % in Fe in $CO_2$ welding; 37.5 % in Cu in SAW, 30 % in Cu in TIG; and 25 % in Pb in SPOT welding. As a whole, 76 Workers(22.4%) were exposed to high concentration of any of the metals above KPEL. 4. There were differences in airborne concentration of metals such as Al, Cd, Cr, Cu. Fe. Mn, Mo, Ni, Pb, Si, Sn, Ti and Zn by industry types. These concentrations were higher in shipyards and steel heavy industries than in automobile assembly and manufactures. Workers exposed to higher concentration of Pb above KPEI amounted to 7.4 % of workers(7/94) in automobile assembly and manufactures. In shipyards, 19.2 % of workers(19/99) were over-exposed to Mn and 7.1 % (7/99) to Fe above KPEL. In steel heavy industries, 14.4 %(21/146), 7.5 %(11/146) and 13 %(19/146) were over-exposed to Mn, Fe and Cu, respectively. As a whole, 76 out of 339 workers(22.4%) were exposed to any of the metals above KPEL. 5. Blood levels of Cd, Cu, Fe, Mn, Pb, and Zn in welders were $0.11{\mu}g/100m{\ell}$, $0.84{\mu}g/m{\ell}$, $424.4{\mu}g/m{\ell}$, $1.26{\mu}g/100m{\ell}$, $5.01{\mu}g/100m{\ell}$ and $5.68{\mu}g/m{\ell}$, respectively, in contrast to $0.09{\mu}g/100m{\ell}$, $0.70{\mu}g/m{\ell}$, $477.2{\mu}g/m{\ell}$, $0.73{\mu}g/100m{\ell}$, $3.14{\mu}g/100m{\ell}$ and $6.15{\mu}g/m{\ell}$ in non-exposed control groups, showing significantly higher values in welders but Fe and Zn.

• Journal of Preventive Medicine and Public Health
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• v.28 no.1 s.49
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• pp.43-57
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• 1995

In order to study the effect of welding fume exposure upon the pulmonary function test, we examined 131 shielded arc welding workers, and 152 $CO_2$ arc welding workers as cases and 177 control workers for their general characteristics, and forced vital capacity (FVC), forced expiratory volume in one second $(FEV_{1.0})$, forced expiratory volume in one second as a percent of FVC $(FEV_{1.0}%)$, and maximal mid-expiratory flow (MMF) were obtained from the spirogram. In shielded arc welding group and $CO_2$ arc welding group, FVC, $FEV_{1.0},\;FEV_{1.0}%$, and MMF were significantly decreased than control group, especially marked in the MMF finding. The distribution of workers below normal range was as follows. in the shielded arc welding group, 2 workers(1.5%) for FVC, 17 workers(13.0%) for $FEV_{1.0}$, 5 workers(3.8%) for $FEV_{1.0}%$, 28 workers(21.4%) for MMF, and in the $CO_2$ arc welding group, 3 workers(2.0%) for FVC, 25 workers(16.4%) for $FEV_{1.0}$, 8 workers(5.3%) for $FEV_{1.0}%$, and 37 workers(24.3%) for MMF, and significant increase by exposure duration was found in MMF. The distribution of workers who had ventilation impairment was as follows: 5 workers(3.8%) for obstructive type, 2 workers(1.5%) for restrictive type in the shielded arc welding group, and 7 workers(4.6%) for obstructive type, 2 workers(1.3%) for restrictive type, and 1 worker(0.6%) was combined type of the $CO_2$ arc welding group. In the respect of these results, the significant pulmonary function and ventilatory impairment were observed in welding fume exposed workers who had not abnormal finding in chest X-ray, and MMF considered as the most sensitive pulmonary function index by welding fume exposure. Therefore even if it is hard to doing pulmonary function test in the first health examination of workers according to the Industrial Safety Health Act in the welding fume exposure workers, it is desirable to consider doing PFT. Also evaluating the ventilation impairment, it is necessary, to observe the change of MMF that marker of effort-independent portion.

• Journal of radiological science and technology
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• v.23 no.2
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• pp.43-54
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• 2000

This paper will present the result of research which was done with 201 places on the actual condition of using dental diagnostic radiography unit and the protection of radiography. The purpose of this paper is to comprehend the actual condition of using dental x-ray unit and to protect when they do radiation work. Moreover this paper was completed to prepare basic materials that could be helpful to reduce the exposure from radiation. This paper obtains the following result. 1. On radiation photographing work in the dentist office, 50.3% of dental hygienists treat this job, and 19.2% of assistants, 10.8% of dentists, 5.6% of radiolotechnologists and 4.2% others performed this job. 2. The case that radiation worker is educated about diagnostic radiography safety supervision has been shown 14.4% and uneducated case has been shown 78.1%. 3. The result about the actual condition of using the oral diagnostic radiation per day was that a number of film which take photograph again (less than 1 exposure) was 40.3%. Normal photographing($1{\sim}10$ exposure) was 85.1% which is the highest percentage. Using the bitewing film and occlusal film was 7.0%, and 12.4% respectively. The percent that they use cephalo film and panoramic film was 16.4% 29.8% respectively. 4. Dental intra diagnostic radiography unit made in $1996{\sim}2000$ was 24.9% and the one made in $1991{\sim}1995$ was 19.9%, in $1986{\sim}1990$ was 19.9%, in 1985 was 9.5% according to the answer. On kVp, they use 60 kVp mostly(61.7%) and On mA, they use 10 mA with the highest percent(66.7%). On the dental extra diagnostic radiography units which are used for doing the extra oral radiography, the one made in $1996{\sim}2000$ was 13.4%, in $1991{\sim}1995$ was 9.5%, in $1985{\sim}1990$ was 2.0% according to the answer. They use $71{\sim}80\;kVp$ with 10.9% and $60{\sim}75\;kVP$ with 9.5%. They use less than 10 mA with 19.4% and $11{\sim}15\;mA$ with 2.5%. $16{\sim}20\;mA$ with 1.5%. But the case they exactly do not know how much mA they use or they do not have any mA was 76.6%. 5. General characteristics and the part of protection through the protective equipment by operator are completed with 89.1%. They have shown the similar difference in the relationship with age(p<0.001), experience(p<0.05) and in-patient(p<0.05). 6. When they take photographs of radiation with general quality, how far they keep the proper distance from the cone is as follows, Keeping safe distance is 12.9% according to the answer with the low percent. This result is similar with the difference related in experience(p<0.05) and work(p<0.05), the area of working(p<0.05) and in-patient(p<0.05). 7. The answer about the question-if they hold the tube head when they take photographs with general characteristics is as follows. The answer that they never hold the tube head and cone occupies 62.7% with the highest percent. It is shown the similar difference with age(p<0.05). 8. According to the study that they put on dosimeter with general characteristics is as follows. 64.7% has never put on the dosimester with the highest percent. 33.8% showed similar differences with experience(p<0.05), work(p<0.001), the area of work(p<0.005)and in-patient(p<0.001).

• Journal of Preventive Medicine and Public Health
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• v.22 no.3 s.27
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• pp.389-397
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• 1989

To identify the problems in child rearing practice of employed mothers in urban poor area, all of 201 women with children under 6 years old living in Yun San 3 Dong, a poor area of Pusan city, were interviewed with a questionnaire by a trained interviewer from 10th April to 10th May 1989. Among 201 women, 51 women were employed and 150 women were unemployed. Of the employed mothers 78.5% got their jobs because of economical need and 31.4% of them worker for 60-69 hours per week. Their average monthly income was 100,000-190,000 Won in 33.4% and 200,000-290,000 Won in 25.4% Breast milk was fed in 66.0% of the children of unemployed mothers while 49.0 of the children of the employed mothers were breast-fed (p<0.05). The most common reason for not breast feeding was shortage of breast milk among unemployed mothers (58.9%) but that of the employed mothers was their job(63.6%). The basic immunization for children was completed in 70.5% of children of employed mothers as compared with 82.0% of the children of the unemployed mothers were completely immunized (p>0.1). Accident experience rate of children among the employed mothers was 23.5 a and that of the children of the unemployed mothers was 17.3% . The most common cause of acident in children of the unemployed mothers was carelessness while they were playing(34.6%) but in children of the employed mothers it was traffic accident(25.0%) and falling(25.0%). Most of the traffic accidents took place while the children's brother or sister of age under 14 years were baby sitting. When the accident took place 73.1% of the unemployed mothers were just at home, but 58.3% of the employed mothers were out of home for work. In case of the employed mothers, 58.7% of their children were looked after by an adult mainly grandparents, 15.7% by the children's brothers and sisters under 14 years old, and 3.9% of the children were left alone. A majority of the unemployed mothers wanted to get a job if someone could take care of their children. To facilitate the women employment and for the safety and health of the children, good nurseries for working mothers need to be established at a cost they can afford.

• Journal of the Korean Society of Radiology
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• v.12 no.7
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• pp.895-908
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• 2018

As modern science is developed and advanced, examination and number of times using radiation are increasing daily. General diagnostic X-ray generator is installed on stationary form, But X-ray generator was developed because patient who is in the intensive care unit, operation room, emergency room can not move to general x-ray room. What we examine patient by x-ray generator is certainly necessary, So patient exposure is inevitable. but reducing radiation exposure is highly important matter about radiation technology, guardian, patient in the same hospital room, nurse etc. For this reason, rule regarding safety control of diagnostic x-ray generator revised for radiation worker, patient and protector proclaim that mobile diagnostic x-ray shield must placed in case of examine different location excluding operation room, emergency room, intensive care unit. But, radiogical technologist is having a lot of difficulties to examine with mobile x-ray generator, diagnostic x-ray shield partition, image plate and lead apron. So, when we use x-ray generator, we manufacture shield tools can be attached to the mobile x-ray generator On behalf of x-ray shield partition and conduct analysis and in comparison to part of body and distribution of dose rate and find way to reduce radiation exposure through distribution of dose rate of patient within the radiogical technologist, medical team. Mobile x-ray generator aimed at SHIMADZU inc. R-20, We manufactured equipment for shielding x-ray scattered x-ray by installing shielding wall from side to side based on support beam on the mobile x-ray generator. Shielding wall when moving can be folded and designed to expand when examine. Experiment measured five times in each by an angle for dose rate of eyes, thyroid, breast, abdomen and gonad on exposure condition of upper and lower extremity, chest, abdomen which is examined many times by mobile x-ray generator. We used dosimeter RSM-100 made by IJRAD and measured a horizontal dose rate by body part. The result of an experiment, shielding decreasing rate of the front and the rear showed 77 ~ 98.7%. Therefore using self-production shielding wall reduce scattered x-ray occurrence rate and confirm can decrease exposure dose consequently. Therefore, through this study, reduction result which is used shielding wall of self-production will be a role of shielding optimization and it could be answer about reduction of medical exposure recommended by ICRP 103.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.1
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• pp.65-73
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• 2019

In order to increase the production efficiency of the ship and shorten the production cycle, it is important to evaluate the accuracy of the ship components efficiently during the drying cycle. The accuracy control of the block is important for shortening the ship process, reducing the cost, and improving the accuracy of the ship. Some systems have been developed and used mainly in large shipyards, but in some cases, they are measured and managed using conventional measuring instruments such as tape measure and beam, optical instruments as optical equipment, In order to perform accuracy control, these tools and equipment as well as equipment for recording measurement data and paper drawings for measuring the measurement position are inevitably combined. The measured results are managed by the accuracy control system through manual input or recording device. In this case, the measurement result is influenced by the work environment and the skill level of the worker. Also, in the measurement result management side, there are a human error about the lack of the measurement result creation, the lack of the management sheet management, And costs are lost in terms of efficiency due to consumption. The purpose of this study is to improve the working environment in the existing accuracy management process by using the augmented reality technology to visualize the measurement information on the actual block and to obtain the measurement information And a smart management system based on augmented reality that can effectively manage the accuracy management data through interworking with measurement equipment. We confirmed the applicability of the proposed system to the accuracy control through the prototype implementation.

• Journal of the Korean Society of Radiology
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• v.15 no.1
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• pp.45-54
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• 2021

This study was written to create educational content in non-destructive fields based on Mixed Reality. Currently, in the field of radiation, there is almost no content for educational Mixed Reality-based educational content. And in the field of non-destructive inspection, the working environment is poor, the number of employees is often 10 or less for each manufacturer, and the educational infrastructure is not built. There is no practical training, only practical training and safety education to convey information. To solve this, it was decided to develop non-destructive worker education content based on Mixed Reality. This content was developed based on Microsoft's HoloLens 2 HMD device. It is manufactured based on the resolution of 1280 ⁎ 720, and the resolution is different for each device, and the Side is created by aligning the Left, Right, Bottom, and TOP positions of Anchor, and the large image affects the size of Atlas. The large volume like the wallpaper and the upper part was made by replacing it with UITexture. For UI Widget Wizard, I made Label, Buttom, ScrollView, and Sprite. In this study, it is possible to provide workers with realistic educational content, enable self-directed education, and educate with 3D stereoscopic images based on reality to provide interesting and immersive education. Through the images provided in Mixed Reality, the learner can directly operate things through the interaction between the real world and the Virtual Reality, and the learner's learning efficiency can be improved. In addition, mixed reality education can play a major role in non-face-to-face learning content in the corona era, where time and place are not disturbed.

• Journal of Korean Society of Forest Science
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• v.111 no.4
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• pp.567-582
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• 2022

Chainsaw use for motor-manual timber harvesting in South Korea is associated with worker safety issues. However, forestry operations such as timber harvesting have already been mechanized to reduce hazards to workers and increase productivity. This study analyzed the productivities and costs of felling and processing, felling and processing using an excavator-based stroke harvester for Pinus rigida and Quercus mongolica stands. To efficiently operate the stroke harvester, we developed a regression equation to estimate the productivities of felling and processing, felling, and processing operations,and we conducted sensitivity analysis of the operation costs using DBH and machine utilization. The felling and processing productivity was 6.53 and 4.02 m³/SMH for P. rigida a nd Q. mongolica, respectively, and the cost was 17,983 and 29,210 won/m³, respectively. The felling productivity for P. rigida a nd Q. mongolica wa s 40.9 and 23.0 m³/SMH, respectively, and the cost was 2,667 and 4,743 won/m³, respectively. The processing productivity for P. rigida and Q. mongolica was 8.25 and 7.75 m³/SMH, respectively, and the cost was 15,296 and 16,283 won/m³, respectively. In the developed regression equation, the DBH, traveling distance, and number of cuttings were found to be important factors (p<0.05). Therefore, it is necessary to construct a DB considering the various conditions and species associated with harvester operations, and further research is needed to increase the accuracy of predicting operation productivity and costs.

• Journal of Society of Preventive Korean Medicine
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• v.5 no.2
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• pp.40-68
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• 2001

In this study, grade of subjective symptom appealed by laborer of Jeollabuk-do was evaluated using questionary regarding factor made effect on musculoskeletal disease and in addition, studied relationship with health promotion life style of them. Based on the result, relationship of general characteristics of musculoskeletal subjective symptom and life-style of the subjects was concluded as below. 1. General characteristics of study subjects were as following. Ratio of male was higher as 57.7% of male and 42.2% female and age distribution was 5.1% of 20s, 34.99% of 30s, 36.3% of 40s and 23.7% of 50s and therefore, $30{\sim}40$ aged groups showed highest ratio. Most subjects (74.9%) was married status and in case of education level, high-school graduate and dropout (23.3%) and over-college graduate (46.8%) showed highest distribution. $1{\sim}2$ Mil. KRW (29.5%) and $2{\sim}2.99$ Mil. KRW (21.2%) is the main income distribution and however there was high ratio of non-reply (29.0%). In case of employment period, $10{\sim}14$ years (15.3%) and over 15 years (29.6%) showed highest ratio and there were many non-reply (39.4%) and in addition, 67.6% replied as own house and 14.3% as lease on deposit base in question of residence type. 2. Subjects showed high ratio of subjective symptom appeal of 62.79% and many cases (50.23%) appealed 1 or 2 symptoms. Symptom by body region was 29.8% (waist), 27% (shoulder), 21.2% (knee), 15.5% (neck), 9.5% (ankle), 8.1% (wrist) and 5.0% (elbow) in order. In case of relationship with general characteristics, female comparing with male, non-residence of own house, subjects with lower education level and employment period of $10{\sim}14$ years showed higher appeal rate and kind of symptoms than others. Therefore, it was concluded that rate of musculoskeletal symptom appeal have close relationship with gender, level of living, education level, age and employment period. 3. In case of severe pain of upper body except waist and ankle, it was appealed in both or right side and it means that upper body pain is originated from right side and right region pain is transited to both region pain. In addition, there was 39.41% of non-reply to existence of right-left region pain and therefore, it was evaluated that, in may cases, there was no awareness of their own symptom condition even on subjective symptom. 4. Degree of pain was, as pain over middle level, evaluated as 2.79 on full mark of 4.0 and in order of waist (2.97), ankle (2.83), knee (2.82), wrist (2.82), neck (2.79), shoulder (2.70) and elbow (2.62). In addition, 71.97% appealed $2{\sim}3$ cases for the latest 1 week. Owing to subjective symptom, 54.95% drop into hospital or pharmacy, 10.32% made temporary retirement or absence, 7.99% transferred into more comfortable duty and $39.4{\sim}54%$ experienced one or more managing mentioned above. 5. Fulfillment of health promotion life style of subjects was evaluated on full mark of 4.0 and total score was 2.63. Average mark of each area was personal relationship (3.05), self-realization (2.92), stress management (2.63), health control (2.48), physical exercise (2.19) and nutrition management (2.19) and personal relationship was highest and physical exercise and nutrition management were lowest. As general characteristics influencing health promotion life style, gender, residence style and employment period showed significant difference. Male showed higher mark than female and showed higher mark in order of own house, others, lease on deposit base, monthly rent. Subjects with longer employment period showed higher mark with significant difference. 6. Accounting of factor influencing each area of health promotion life style, self-realization showed significance in marriage status, income, residence style and education level and health control in age, residence style and employment period. Physical exercise showed significant difference in gender, age, residence style and employment period and nutrition in gender, age, residence style and employment period. Stress management showed significant difference in residence style and employment period and however not in personal relationship. 7. Health promotion life style relating with existence and kind of pain showed significant difference in all area except personal relationship area. In absence of pain, there was statistically significant high score in all area even in total health promotion life style and all area. Accounting of kind of pain, cases of $1{\sim}2$ kinds of pain and $5{\sim}6$ kinds of pain showed relatively high score and it was lower than mark of subject stated absence of pain. 8. Subjects appeal symptom were classified by symptom region and difference of total and each areas were evaluated. General area (p=0.002), self-realization (p=0.012), health management (p=0.023), physical exercise (p=0.028), nutrition management (p=0.028) and stress control (p=0.001) showed statistically significant difference and not in personal relationship area. Especially, elbow, shoulder and neck area marked high and group appealed pain of knee, arm and elbow, foot and ankle marked low. Based on those results, subjective symptom should be accounted seriously in diagnosis of occupational musculoskeletal disease of laborer and among subjective symptom, general characteristics of gender, age, condition of living, education level and employment period make effect. Generally subject appeal symptom marked lower than subject without symptom appeal and it means that life management of subject appealing musculoskeletal pain make important role in management and treatment of occupational musculoskeletal disease.