사료첨가물로써 완충제와 Fly - ash 의 첨가TMR 사료가 면양의 소화율 및 반추위내 발효특성에 미치는 영향

고영두,김재황,이수칠,이종찬,김삼철 한국영양사료학회 1999 韓國營養飼料學會誌 Vol.23 No.3

본 시험은 화력발전소의 전력 부산물로 발생되는 Fly-ash와 현재 시판되고 있는 완충제를 각각 1%씩 TMR 사료에 첨가하여 시험사료의 일반 성분을 분석하였으며, 면양을 이용한 소화율과 반추위액의 발효특성을 조사하였다. 시험사료는 체중의 2%를 급여하였으며 사양시험은 3 × 3 Latin square법으로 실시하였다. 조지방 소화율은 대조구, TMR + Buffer 및 TMR + Fly-ash 급여구가 각각 71.7, 74.1 및 77.2%로서 Fly-ash를 첨가함으로서 유의하게 높게(P<0.05) 나타났다. ADF 소화율(69.9∼71.2%)과 NFE 소화율(72.1∼72.9%) 및 가소화영양소 총량(65.7∼66.1%)은 처리구간 유의한 차이는 없었다. 반추위액 pH는 사료급여 30분에는 차이가 없었으나 사료급여 2시간 후부터는 Fly-ash 첨가구에서는 계속 증가 (P<0.05)되어 효과가 가장 높았다. 반추위액의 NH₃-N 함량은 사료급여 30분 후 TMR구가 높게(P<0.05) 나타났으나, 사료급여 2시간 후에는 TMR + Buffer 급여구가 타 처리구에 비하여 낮게(P<0.05)나타났다. 반추위액의 total-VFA 함량은 각 처리구에서 사료급여 후 2시간까지는 증가(P<0.05)한 후 감소하였으며, 그 효과는 TMR + Buffer 급여구가 가장 높게 나타났다. 이상의 결과를 종합하면 TMR 사료에 완충제나 Fly-ash를 첨가함으로서 PH(6.2∼6.8)를 조절하고 소화율을 향상시켜 사료 이용성을 개선시켰으며, 특히 Fly-ash는 완충제로서의 역할이 우수하여 고가인 시판 완충제의 대체효과가 높은 것으로 인정된다. This study was carried out to investigate the effects of addition on buffer (1%) and Fly-ash (1%) when TMR diet fed as a basic diet. Trial diets were estimated for the chemical compostion, and investigated the nutrient utilization of trial diets to that of sheep was given a diet of 2% of the body weight (dry matter basis) daily. The feeding trials were assigned to 3 × 3 Latin square design. During feeding trials, the digestibility and fermentation characteristics in the rumen were measured. Digestibility of crude fat of TMR + Buffer group (74.1%) and TMR + Fly-ash group (77.2%) were significantly higher (P<0.05) than that of control group (71.7%). But There were no differences in digestibility of neutral detergent fiber (NDF), nitrogen free extract (NFE) and total digestible nutrients (TDN) among the three treatments. Ruminal pH were no differences between treatments at 30 minute after feeding, and ruminal pH of 1% TMR + Fly-ash group were tended to increase throughout the fermentation periods at 2 hours after feeding. Ruminal ammonia-N of 1% TMR+Fly-ash group (15.39 ㎎/100㎖) were significantly higher (P<0.05) than the other treatments. That of 1% TMR + Buffer group was significantly lower (P<0.05) than the other treatments at 2 hours after feeding. Ruminal total-VFA of 1% TMR + Buffer group were tended to increase throughout the fermentation period. Ruminal total-VFA in all treatments reached the maximum value at 2 hours but indicated low tendency from at 2 hours after feeding. In conclusion, 1% Fly-ash group was increased nutrient digestibility and mainteined optimal rumimal pH (6.2∼6.8) in comparision with other treatments. Alternatively, utilization of Fly-ash will be contributed to reduce the cost of production.

독성물질 사용 저장시설에 대한 개인적 위험성 산정에 관한 연구

김성빈,김윤화,이철,엄성인,고재욱,백종배 한국산업안전학회 1997 한국안전학회지 Vol.12 No.1

These days leakage incidents of toxic materials cause serious effects on the nearby residents as well as the workers around the accidents accompanying massive material losses and human damages through widening influencial areas. The risk measure through adequate quantitative analysis as well as the qualitative analysis of the leakage incidents of toxic materials becomes an urgent issue. The damage, of the leakage incident on the surrounding area of the dangerous toxic material facilities was calculated quantitatively by adopting several models in this research. First, the calculations of the leakage velocity from the factories were performed by using source model for the assessment of the influential area, and the damages on the nearly residents were calculated by using the dispersion model and the effect model. The probability of the incidents was computed based on $quot;The manual for classification and priorization of major incidents$quot; published by IAEA(International Atomic Energy Agency). Above calculated damage area and incident probability were further adopted in this study to induce the individual and societal risk, quantitatively. The calculated data of the real incident of the toxic material leakage showed reasonable agreements to the actual damage of the incidents, which showed a validity of this study. The result of this study might be a helpful measure for predicting damages and preparing safety systems for similar kinds of incidents.

두께가 일정하지 않은 재료에서 경사진 균열의 성장거동에 관한 연구

조명래,표창률,박종구,고명훈 한국산업안전학회 1997 한국안전학회지 Vol.12 No.4

The effect of geometry factors on the combined mode stress intensity factor behaviors of a slant crack in a non-uniform thickness material was analysed by 2-dimensional theoretical analysis. The analysis is based on the Laurent's series expansions of complex potentials where the complex coefficients of the series are determined from the compatibility and the equilibrium conditions of the thickness interface. and the stress free conditions of the crack surface. In numerical calculations the perturbation technique is employed. The expressions for the crack tip stress intensity factor are given in the form of power series of dimensionless crack length λ, and the function of crack slant angle α and thickness ratio β . The results of numerical calculations for each problems are represented as the correction factors F(λ, α, β). The results clearly show the following characteristics : The correction factors of the combined mode stress intensity factors for a non-uniform thickness material can be defined in the form of F(λ, α, β). The stress intensity factor values for a given crack length are decreased with increase of thickness ratio β.

LPG 탱크로리 수송중 위험성 평가에 관한 연구

이재준,김윤화,엄성인,고재욱,백종배,윤성렬 한국산업안전학회 1997 한국안전학회지 Vol.12 No.4

Demand of LPG and LNG will increase continuously due to high calories, clearness, and convenience for usage. These gases are used widely for power plants, industrial plants, and domestic fuel. But accidents related with gas are increasing in proportion to increment of gas usage. Especially, LPG has high ignitability due to weak dispersion to air and accumulation at low place because LPG is heavier than air. There are many hazards during transportation as well as production, storage, and usage of LPG. Commonly, tank lorry is used for inland transportation of LPG. If tank lorry were to raise leakage incidents and then LPG released during transporting, the accidents cause serious effects on the environment as well as human damage of surrounding area. In this study, therefore, hazards which cause LPG of tank lorry to leak during transportation were identified and risk of LPG transportation was assessed quantitatively. Also, the result of this study might be a useful measure for predicting damage and preparing safe transportation strategies of LPG tank lorry.

데이터베이스를 이용한 산업시설의 위험성평가시스템 구축에 관한 연구

김성빈,김윤화,엄성인,고재욱,김기수,백종배 한국산업안전학회 1998 한국안전학회지 Vol.13 No.1

Recently, industrial accidents have occurred in various patterns due to the diversity of industries and the integration of facilities. Especially, the major accidents affect broad area and result in huge loss of lives and properties. Domestic researches on techniques for keeping away from such hazardous danger have been actively performed but their activities are limited in some institutes and universities. In advanced countries, integrated management systems like Seveso Directive of EU and OSHA(Occupational Safety and Health Act) of U.S.A. have been legislated along with the systematic research activities. In Korea, the integrated safety management systems called SMS(Safety Management System) and PSM(Process Safety Management) have been applied to major industries. These systems made chemical industries manage the process safety information by collecting and arranging safety data by themselves. In order to implement the system successfully, it is urgently required to prepare a tool for searching and accumulating process safety data systematically. In this study, a computerized prototype of Risk Assessment System which is essential to SMS and PSM was developed as a main system and data base as subsystem to handle safety information.

위험성 평가 프로그램 PML - Chem 개발

김윤화,고재욱,김형석,신동일,김인원 한국산업안전학회 1999 한국안전학회지 Vol.14 No.2

This study is to develope the quantitative risk assessment program for consequence analysis of fire and explosion (PML-Chem), which is applicable to the chemical plants. The advantages of PML-Chem is easy to use and acquire results. Especially, PML-Chem was embedded real weather condition database for major chemical plants in ○○ complex in country. Also, reliability of PML-Chem was verified through comparing PML-Chem with PHAST-Professional which is already commercial.

구속전단가공 (ECAP) 한 Al 합금의 미세조직

문인기,고흥석,장준연,최성규 대한금속재료학회(대한금속학회) 1999 대한금속·재료학회지 Vol.37 No.12

The study is an attempt to understand the basic characteristics of ECAP(Equal Channel Angular Pressing) which gives large shear deformation without any change in the dimension of material. Microstructure comparison was performed between pure Al and Al-7 wt% Si alloys after the ECAP. Emphasis was put on the microstructural change of Al-Si alloys consisting of two phase (primary Al + eutectic Si) where eutectic Si appears different shape and size depending on the modification. The pressing leads to the development of subgrain bands of Al and the fracture of unmodified eutectic Si. The eutectic Si may form dislocation tangles by acting as an obstacle to movement of dislocation, which can be proved with the location of eutectic Si on recrystallized grain boundary. It is obvious that ECAP results in a fine grain structure in Al-Si alloy without decohesion between Al matrix and eutectic Si.

구속전단가공법 (ECAP) 에서 전단변형 특성

문인기,고흥석,장준연,최성규 대한금속재료학회(대한금속학회) 1999 대한금속·재료학회지 Vol.37 No.4

The study focuses on the basic deformation mechanism of ECAP (Equal Channel Angular Pressing) which gives a large shear deformation without change in the reduction of area. A model deformation in which a plasticine is pressed through a transparent die shows a typical shear deformation in detail. ECAP was performed on a commercial pure aluminum and an Al-7%Si alloy in order to investigate the change in the microstructure after ECAP. Friction force between specimen and die acts to prevent uniform shear deformation of a specimen. ECAP significantly reduces grain size of both aluminum alloys below the order of micronmeter by giving a large shear deformation, which provides a new method for grain refinement. A drastic increase in the yield strength combined with a small increase in the strain hardening is observed in both ECA pressed aluminum alloys. The ECAP is believed to be very effective in the grain refinement.

슬래그중 고체철의 산화거동에 관한 속도론적 고찰

백종문,이홍기,고정호,민동준 대한금속재료학회(대한금속학회) 1998 대한금속·재료학회지 Vol.36 No.12

The kinetic experiments have been made on iron oxidation in slag by oxidizing gases at 1387∼1500℃. The effect of temperature, FeO content and oxygen potential of gas on the reaction rate have been examined. The iron oxidizing rate is considerably increased with increasing temperature and FeO content in slag. It was also found that the rate controlling step of reaction have been depended on the temperature, FeO content in slag and (P_(co₂)/P_(co) as an oxygen potential at gas/slag interface. The dependence of the overall reaction rate constant on temperature and initial FeO content in slag at 1450℃ could be expressed as follows; log k_(overall) = -0.36-10,820/T[㏖/㎠·sec·atm] k_(overall) = 1.04×10^(-7)(wt%FeO)^(0.75)[㏖/㎠·sec·atm] In condition of high oxygen potential such as high FeO content and (P_(co₂)/P_(co)), the chemical reaction at interface between slag and gas might play a important role as a rate controlling step of overall reaction, which is controlled by the dissociation of CO₂ at slag/gas interface. But in case of low (P_(co₂)/P_(co)), mass transfer and chemical reaction at interface between slag and iron become important as a rate controlling step. The reaction mechanism of iron oxidization in slag by gas have been discussed in terms of rate constant for elementary reactions.

대전인체의 방전위험성 평가를 위한 모델 및 예방진단 프로그램 개발

김두현,김상철,고은영 한국산업안전학회 1998 한국안전학회지 Vol.13 No.3

This paper presents a study on the development of discharge model and computer program for assessing the risk of electrostatic discharge(ESD) of charged human body. This ESD event is modelled as a two-body problem using spherical conductors, simulating the approach of a charged conductor (human body) to a second conductor (electronic equipment). The charge/discharge process for the model is formulated as a matrix of equations by Maxwell's method. Body potentials, energies and the charge transfer during a discharge are calculated. The developed program, based on the suggested scheme in this paper, is applied to a sample system. The results provide a better understanding of ESD event and demonstrate the usefulness of two-body model in practical applications.