• Journal of the Ergonomics Society of Korea
• /
• v.34 no.3
• /
• pp.279-291
• /
• 2015

Objective: The purpose of the study is to evaluate appropriate weight for aged farmers in manually handling livestock feed in bags using ergonomic methods. Background: In the livestock industry in South Korea, despite the trend of aging of labor manpower, heavy items are still manually handled in many farms. In particular, among stockbreeding works, the handling of feed in bags weighing 25~30kg is reported as a cause of frequent injuries and musculoskeletal system diseases. However, studies on the standard for recommended weight allowed considering the physical characteristics of aged farmers older than 60 years with greatly decreased physical strength and muscle strength are insufficient. Method: To evaluate appropriate weight for handling of heavy livestock feed in bags, physical techniques for measuring recognized levels of physical work loads, the NLE (NIOSH lifting equation) a method that is an observation type technique, and an ergonomic modeling technique to predict compressive force imposed on L5/S1 were used. Subjects who participated in the experiment were organized into two groups of males/females with mean age exceeding 60 years, and lifting tasks were evaluated for nine weight levels. Results: Based on the results of psychophysical measurement, females showed a tendency of more drastic increases compared to males when weight was over 19kg. The results of estimation of regression models for the weight, 18.0 kg ($r^2=0.97$) and 15.3kg ($r^2=0.97$) were evaluated as stable load for males and females, respectively. In addition, both the observation type evaluation and ergonomic model evaluation showed stable loads in a range of 15~18kg. Conclusion: Given the results of the study, the weight of the feed in bags currently distributed to farms can become a cause of not only overexertion but also farm work related disasters such as musculoskeletal disorders and safety accidents. Providing livestock feed in bags weighing not more than 19kg for aged farmers is judged desirable, and managerial improvement for this matter is considered necessary. Application: The results of the present study can be utilized as useful data for institutional improvement of the weight of livestock feed in bags.

• Journal of Sericultural and Entomological Science
• /
• v.20 no.1
• /
• pp.15-23
• /
• 1978

This studies have been carried out for several years to develop more better urea resin treating process on silk textiles which may be better crease resist without harming on the textile touch feeling. Specially, this paper payed attention to minimize the necessary formaldehyde content to be condensed with urea and created a new processing method which is named as Homo Metalic Urea Resin found to be better than urea resin process. The obtained results are as followings. 1. The prepared urea resin was found to be smell-less because of minimized formaldehyde content is the least than any other reports carried out before than this. 2. A new type of urea resin has been created by using uric 2incchloride and formaldehyde which is named as Homo Metalic Urea Resin. This processing method may carry both weighing process and urea resin process. 3. Crease resistance, stiffness and bulkiness were increased through such resin treats. Homo metalic urea resin process showed better results than the urea resin process. 4. Spun silk or low twisted silk have shown better crease resistance than raw silk or high twisted silk upon the both resin treats. 5. Both treat methods were found to be good economical feasibility upon the silk finishing process. 6. Tenacity and elongation of silk fibers were found to decrease some what because of grafting or weighing results. 7. Wooly silk has been also created with specific urea resin process. Such silk could be obtained by formaldehyde gas treat with urea soaken silk in a chamber, which induced to form scale on the surface of silk fibers.

• Korean Journal of Community Nutrition
• /
• v.15 no.6
• /
• pp.760-775
• /
• 2010

This study was performed to investigate the validity of food photographs for estimating individuals' dietary intakes and compare it with other dietary assessment methods. Subjects were 7 professors, 2 researchers, 12 dietitian and 16 graduate students majoring in food and nutrition. Among the subjects, 20 subjects had research experiences in the dietary intake survey more than one year while 17 had not. Each subject estimated 50 food portions displayed in computer monitor by comparing with standard food photographs, which were weighed portions of 28 foods from typical Korean diet. No significant differences between the estimated value and the weighed value of 17 (34%) food portions were shown in research-experienced group and those of 14 (28%) food portions were shown in no-researchexperienced group. 24-hour recall was the most frequently-used method for dietary assessment followed by in the order of food frequency questionnaire, dietary record, diet history and weighing method. After estimating food portions by photographs, 30 subjects (81%) were willing to use the method for dietary assessment because of its convenience and easy communication between researcher and subject. This study suggests that digital photography method would be a useful and convenient new instrument for estimating individuals' dietary intake. However, it is necessary to create standard database for food portions and carry out systematic education for food estimation in order to apply this method in the fields.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.13 no.7
• /
• pp.1422-1428
• /
• 2009

In this paper, we consider an independent type cognitive radio system where secondary users can utilize empty channels that are not currently used by primary users having the license to these channels. In the previous works, secondary users search channels sequently or randomly to detect activities of primary user on channels. These channel searching methods however are not suitable to the characteristics of the wireless environment. Therefore, we propose a channel searching method based on the channel list for the purpose of reducing the channel searching time and improving the throughput of secondary users. In the proposed method, we firstly determine weighting value of each channel based on the history of channel activities of primary users and add the weighing value to current channel state buffer. And then, we search an empty channel from channel with smallest value to one with the biggest value. Finally, we compare the performances of the proposed method with those of the sequential channel searching and the random channel searching methods in terms of average channel searching time and average number of transmissions of secondary user.

• Journal of the Korean Society of Tobacco Science
• /
• v.28 no.2
• /
• pp.83-93
• /
• 2006

The aim of this study is to develop a simple and rapid field method for the determination of chloride content in tobacco green or cured leaves. To set up a practical process, several factors such as the proper sampling position of each leaf, the size of leaf lamina pieces for blending, the substitution of deionized water fur the extracting solution, 0.1N $HNO_3$, the submerging durations before blending, and the standing times before measuring were studied using flue-cured and burley tobacco with a stable and reproducible Chloride Meter, KRK CL-2Z. From the results, chloride contents of tobacco leaves could be analyzed with the Chloride Meter(CL-2Z) using the suspension of 14 mm diameter leaf disks after soaking in distilled water for 30 min., blending with a mini-blender for 30 seconds. The chloride contents measured in this way showed highly significant correlations with ones by the conventional potentiometric method using an ion meter-chloride electrode and $AgNO_3$ titration. In our method, the procedures such as drying, powdering and weighing samples, and using chemical reagents for extraction (0.1N $HNO_3$) and titration(0.028N $AgNO_3$) could be eliminated. These results suggest that the newly constructed method using the Chloride Meter is more efficient to determine the chloride content of tobacco leave in comparison with the one by the Ion $Meter:AgNO_3$ titration.

• Clean Technology
• /
• v.14 no.2
• /
• pp.103-109
• /
• 2008

In this study, in order to develop evaluation method of the cleaning efficiency of residual flux which remains on the surface after soldering with solder paste, a specially designed metal tool is used to reduce spread uncertainty of flux while soldering. Using this tool, the measurement of cleaning efficiency of flux after soldering for some typical alternative semi-aqueous cleaners and 1,1,1-TCE by weighing method was conducted. As the test result of cleaning efficiency for each cleaner at several different cleaning times, the precision of the data is confirmed to within about 4% relative standard deviation (RSD) range. So, it is considered that this would be a good evaluation method for evaluating the cleaning efficiency of the residual flux which remains after solder paste soldering in the alternative cleaning. The results of this test method shows that the cleaning efficiency of ST 100SX and Neozal 750H in the cleaning of residual flux was better than other semi-aqueous cleaners, but its cleaning efficiency was clearly inferior to 1,1,1-TCE.

• Journal of Nutrition and Health
• /
• v.24 no.3
• /
• pp.219-229
• /
• 1991

The longitudinal changes on human milk volume per day and lactational performance of 23 Korean lacto-ovo-vegetarians(primiparae=11, multiparae=12) from 0.5 to 5 months after parturition have been studied by test weighing method. The human milk volume per day tended to increase during lactation. The mean volume (SD, ml/day) at 0.5, 1, 2, 3, 4, 5 months were 502(102), 692(127), 697(100), 684( 125), 757(52), 703(70), respectively. The overall mean volume was 661$\pm$132ml/day. The peak milk volume during the lactation was observed at most lactating women at the 1st month. The distributions of the individual mean volume during the first 5 months of lactation were found over 750m1(8.7% ), 650-750ml(47.9% ), 550-650m1(2l.7% ), and 450-550ml(2l.7% ) The number of feeding per day was 8.1 ($\pm$1.0) at 0.5 months postpartum, which was consistently decreased. However, the mean volume per feeding was increased from 62($\pm$9.5)ml at 0.5 month to 112($\pm$13.3)ml at 5 months postpartum. The milk volume was correlated with the peak volume. and maternal age. but not with weight before delivery. maternal height and birth weight. No differences of milk volume and lactational performance between facto-ovo-vegetarian and nonvegetarian women were observed. This study suggests that the human milk volume cited in the recommended dietary allowances for Koreitns is over estimated.

• Preventive Nutrition and Food Science
• /
• v.1 no.2
• /
• pp.230-233
• /
• 1996

The purposes of this study was to investigate selenium content of human milk and selenium intake of breast-fed infants at each period of lactation longitudinally. The human milk intake in breast-fed infants was measured by test weighing method from 20 lactating mothers at 1,2 and 3 months postpartum. Selenium content in the milks was determined by atomic absorption spectrophotometry with hydride generation after wet digestion of samples. Selenium intake in breast-fed infants was calculated by multiplying human milk intakes by selenium contents. The milk intakes were 640, 726 and 715g/day at 1,2 and 3 months postpartum. The selenium contents in human milk were characterized by a pattern of slight decline with advancing stage of lactation;13.1, 11.5 and 9.8$\mu\textrm{g}$/L at 1,2 and 3 months during lactation. There was a large individual variation at any stage of this study. The mean dietary selenium intakes in breast-fed infants were 8.38, 8.32 and 6.97$\mu\textrm{g}$/day at 1,2 and 3 months postpartum, respectively. The mean daily intakes on a body weight basis were gradually decreased during the course of lactation.

• The Korean Journal of Pharmacology
• /
• v.6 no.1
• /
• pp.15-22
• /
• 1970

The present study is concerned with the demonstration of the relationship between the behavior and the brain concentration of noradrenaline resulted from pretreatment of amphetamine in isolated or aggregated rats. The experimental subjects were rats weighing from 120g to 200g housed 1, 2, and 6 in a cage. Analeptic activity of amphetamine was measured by determining the sleeping time induced by pentobarbital sod. The noradrenaline content in brain was determined with Aminco-Bowmann's spectro-photofluorometer by Lee's modification of Shore and Olin method. Results: 1) The analeptic activity of amphetamine on the sleeping time induced by pentobarbital sod. was more increased in the grouped rats than in isolated animal. 2) In being isolated and grouped rats, the sleeping time induced pentobarital sod, was markedly prolonged by pretreatment of amphetamine. 3) Means of housing rats, e.g., isolation or aggregation did not seem to affect the brain noradrenaline depleting action. 4) Repeated daily parenteral administration of amphetamine sulfate for a period 1 to 3 weeks resulted in decrement of brain noradrenaline concentration in being isolated and grouped rats. 5) The prolongation of sleeping time of the isolated or aggregated rats, when pretreated with amphetamine, compared with that of stock rats, seems to be attributable rather to the means of housing than the variation of the noradrenaline caused by amphetamine.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.31 no.8
• /
• pp.663-671
• /
• 2007

In this work, shape optimization of a wire-wrapped fuel assembly in a liquid metal reactor has been carried out by combining a three-dimensional Reynolds-averaged Navier-Stokes analysis with the radial basis neural network method, a well known surrogate modeling technique for optimization. Sequential Quadratic Programming is used to search the optimal point from the constructed surrogate. Two geometric design variables are selected for the optimization and design space is sampled using Latin Hypercube Sampling. The optimization problem has been defined as a maximization of the objective function, which is as a linear combination of heat transfer and friction loss related terms with a weighing factor. The objective function value is more sensitive to the ratio of the wire spacer diameter to the fuel rod diameter than to the ratio of the wire wrap pitch to the fuel rod diameter. The optimal values of the design variables are obtained by varying the weighting factor.