• Journal of Nutrition and Health
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• v.22 no.3
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• pp.185-193
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• 1989

This study was performed to investigate lead(Pb) detoxification with different dietary protein levels and detoxifying periods in Pb poisoned rats. Forty nine male rats of Sprague-Dawley strain weighing 114$\pm$4g were used and they were fed 1% Pb-15% casein diet ad libitum for 2 weeks. After sacrifying 7 animals as control group, remaining forty two rats were blocked into 6 groups according to body weight. Three groups were fed each detoxifying diet(5%, 15% or 40% casein diet without Pb) for 1 week and the other 3 groups were fed same diets for 3 weeks. The results obtained were summerized as follows ; 1) Liver and kidney weight, bone weight, and bone length were increased with increasing dietary protein level and detoxifying period. 2) Hematocrit values were recovered to normal level during detoxifiying periods but hemoglobin contents in detoxifying diet groups showed no significant difference from those in control group. 3)Pb contents in blood were decreased with increasing dietary protein level, and Pb contents in liver were significantly decreased in high protein diet groups. Pb contents in kidney were significantly decreased during detoxifying period compared to control group, but no significant difference was shown within the detoxifying diet groups. Pb contents in femur were significantly decreased after 3 weeks of detoxifying period but no difference was shown with different dietary protein level. 4) Urinary Pb excretions were significantly increased with increasing dietary protein level. Fecal Pb excretions were remarkably decreased after 3 weeks of detoxifying period, but no difference was showen in fecal Pb excretions with different dietary protein level. Above results suggest that high protein diet improves Pb detoxification by increasing urinary Pb excretion.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.699-704
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• 2001

Until recently, disposal to landfill has been the most convenient way to deal with the increasing amount of residues the shredding industries produce. But the shortage of such disposal sites and the risk that liquid drained from these waste dusts may pollute ground water have increased the environmental pressures to find more effective solutions. The present study is an alternative approach that suggests identifying waste dusts characteristics and selecting an appropriate binder for hazardous materials to reduce the amount of contaminants (mainly lead) that were leaking into the soil. Investigations on the characteristics of automobiles waste dusts show that these materials are composed mainly of cottons and sponge like substances, plastics, rubber, glasses and gravel, metals, and electric wires. Besides, the percentage in weight of organic (inflammable) materials is about 70% and the lead contamination, which has not a ionic but a particulate nature, is particularly remarkable in cottons and sponge like materials. Binding additives such as K-20 and sodium carbonate were not effective but the addition of 5 % of cement (in weight of the investigated sample) followed by a 3-minute stirring and a 4-hour storage could drastically reduce the run off of lead below the maximum authorized level. No addition of water was necessary in this method.

• Journal of the Korean Magnetics Society
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• v.11 no.2
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• pp.50-57
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• 2001

Magnetic inductive probe was designed and assembled for sensing the residual stress developed in the ferromagnetic thin sheet. The residual stress measurement system with this probe could resolve the residual stresses developed in the sheet in terms of principal stress orientation, and magnitude of the principal stress. It was consumed that the obtained probe output voltage from the qualified ferromagnetic Fe-42Ni lead frame sheet and quality-rejected sheet is effectively determined using the developed device. The lead frame sheet which has accumulated a high level of residual stress always showed a distinctive stress distribution and magnitude compared with those of qualified lead frame sheet. Those differences were well resolved as functions of input current or used frequency.

• Journal of Welding and Joining
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• v.35 no.3
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• pp.21-27
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• 2017

A soldering temperature of ($235{\pm}3$) $^{\circ}C$ is described in ISO 9455-15 for the copper corrosion test. However, this temperature is not suitable for performing lead-free solder pastes. We evaluated the compatibility of a lead-free solder paste in the experimental conditions of (Liquidus temperature + ($35{\pm}3$)) $^{\circ}C$. Based on the results after a Cu corrosion test, a proper temperature for Pb-free soldering was (melting point+($35{\pm}3$)) $^{\circ}C$. Criteria used to evaluate corrosion due to discoloration of flux residue is described in ISO 9455-15, but a more quantitative evaluation standard is needed. In this study, experimental error level was estimated by analyzing flux residue after a corrosion test for 72, 500 hours of specimens using EDS analysis with acceleration voltage. It was determined that the copper area at the flux residue boundary is suitable for the EDS analysis area.

• The Journal of Fisheries Business Administration
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• v.30 no.2
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• pp.25-37
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• 1999

Some multi echelon inventory systems carry perishable products. The value of these product reduces as the period of time they spend in the system. In this paper We derive the necessary condition to determine optimal quantity, service level for a perishable product. The systems considered consist of two echelons and carry single item. To determine the optimal order quantity, the demand is assumed to be constant, the holding costs may be different in the echelons, and it allows no shortages. I assumed the price of product decreases by negative exponential function. To determine service level, following assumptions used in the model ㆍlead time is constant. ㆍdemand is normal distribution. ㆍthe product starts to perish at the second echelon. Service level is computed for different levels of lead times and for different variance of demands and for different price functions. The experimental results indicate that the service level in cost is a function of service level in demand and perishability of product. Results of the models exhibit that perishability and the age of the product are critical to determine the lot sizing and service level.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.1053-1059
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• 2009

Construction system modeling can enhance work performance by following the behaviors of a system. System behaviors may originate from physical aspects of a system, namely operation level variables, or from non-physical aspects of a system known as context level variables. However, construction system modelers usually focus on only one type of system variable (i.e., operation level or context level) which can lead to less accurate results. Hybrid modeling with System Dynamics (SD) and Discrete Event Simulation (DES) is one of the approaches that has been utilized to address this issue. In this research, an SD-DES hybrid model of a steel fabrication shop is developed, and the benefits of capturing context level variables together with operation level variables in the model are discussed.

• Journal of Korea Soil Environment Society
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• v.5 no.1
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• pp.55-63
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• 2000

Bentonite has low hydraulic conductivity and high sorption capacity to limit hazardous heavy metals migration, and thus it has been considered as a liner material for the landfill of hazardous wastes. With a domestic bentonite sorption tests were carried out to investigate the adsorption isotherm and the effect of solution chemistry and temperature on adsorption. Freundlich isotherm was applied to fit the experimental data of lead adsorption, which fitted them well. Freundlich constants and correlation coefficient were calculated to be $K_{F}$\;=\;1.14$, n = 1.70, and $r^{2}\;=\;0.99$, respectively. The distribution coefficients($K_{d}$) for the adsorption of lead decreased with increasing initial lead concentration. The IL increased with increasing the pH of solution and sharply increased at pH > 7, which was attributed to the precipitation of lead species. The IL decreased with increasing the ion strength of solution. The $K_{d}$ gave a small increase with the concentration of ${SO_4}^{-2}$, whereas it had a nearly constant level with the concentration of ${HCO_3}^{-}$ in solution. An increase in the temperature of experimental solution increased the $K_{d}$.

• Journal of Korea Water Resources Association
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• v.54 no.spc1
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• pp.1061-1069
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• 2021

Recently, the magnitude and frequency of extreme heavy rains and localized heavy rains have increased due to abnormal climate, which caused increased flood damage in river basin. As a result, the nonlinearity of the hydrological system of rivers or basins is increasing, and there is a limitation in that the lead time is insufficient to predict the water level using the existing physical-based hydrological model. This study predicted the water level at Ulsan (Taehwagyo) with a lead time of 0, 1, 2, 3, 6, 12 hours by applying deep learning techniques based on Deep Neural Network (DNN) and Long Short-Term Memory (LSTM) and evaluated the prediction accuracy. As a result, DNN model using the sliding window concept showed the highest accuracy with a correlation coefficient of 0.97 and RMSE of 0.82 m. If deep learning-based water level prediction using a DNN model is performed in the future, high prediction accuracy and sufficient lead time can be secured than water level prediction using existing physical-based hydrological models.

• Journal of Preventive Medicine and Public Health
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• v.29 no.3 s.54
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• pp.693-700
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• 1996

The purpose of this study was to determine whether workers at a factory next to a lead recycling factory in Pusan, were affected by lead contamination. The mean air lead concentration of lead recycling factory was $0.21mg/m^3(TWA=0.05mg/m^3)$. Thirty-nine male workers of Factory A, Cr. plating factory next to the lead recycling factory were exposed group and a comparison group, 62 male workers of Factory B were selected from another Cr. plating factory about 8.5km away from lead recycling factory. Air lead concentration of each workplace was checked for 4 times from August f to August 20 in 1995 by low volume air sampler. Each subject was interviewed about age, life-style, smoking, work history, and residence etc, and venous blood was drawn for lead measurement by graphite furnace atomic absorption spectrometry. We have observed that air lead concentration and blood lead concentration of Factory A was higher than Factory $B(2.6{\pm}1.6\;Vs.\;1.2{\pm}0.2{\mu}g/m^3,\;14.9{\pm}1.6\;Vs.\;12.2{\pm}1.6{\mu}g/dl)$. We believe that other environmental lead sources such as transportation and residence did not affect air lead and blood lead concentration differences of both factory. We concluded that high air lead and blood lead concentration of Factory A were caused by lead contamination generated by the neighboring lead recycling factory.

• Applied Microscopy
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• v.39 no.4
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• pp.355-363
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• 2009

The purpose of this study was to demonstrate the effect of Momordica Charantia L. water extracts, one of the natural chelator, on the biochemical and enzyme activity changes in the rats liver and kidney caused by lead acetate. Rat approximately 250 g in weight were grouped into the control, lead acetate treated, and the Momordica Charantia L. boiling water extracts treated after lead acetate groups. Lead acetate (1,000 ppm) and Momordica Charantia L. water extracts (5%, 10%) were delivered drinking water. Serum AST, ALT and BUN were measured, histological alteration of liver and kidney were examined by light microscopy. Momordica Charantia L. extract group was decreased serum AST, ALT and BUN level induced by lead. Optical observations of liver tissue, lead group were observed necrosis of hepatic cells and infiltration of inflammatory cells, but Momordica Charantia L. extract group was observed only slight infiltration of inflammatory cells around the central vein. Optical observations of kidney tissue, lead acetate induced atrophy and necrosis of glomerulus and infiltration of inflammatory cell around renal tubule. For the group treated with Momordica charantia L. extract, the glomerulus was similar to the control, some around the renal tubule was observed infiltration of inflammatory cells. In conclusion, Momordica Charantia L. water extract may protect the lead-induced toxicity on liver and kidney.