• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.11 no.1
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• pp.85-91
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• 2001

Background : It goes without saying that cumulative trauma disorders is spreading to various types of occupation in many advanced countries including America, and it forms considerable rate of total occupational disorders already. and as the result of it, the seriousness of worker health problem and economic loss owing to production loss, recuperation expense, etc. are on the increasing trend through whole society. In case of Korea, the related measures as well as accurate fact-finding survey data on cumulative trauma disorders aren't prepared in detail, so it implies forward problem would be serious. Purpose : The purpose of this study is to draw the risk factor of cumulative trauma disorders in production factory, to forecast the rate of occurrence of cumulative trauma disorders on the basis of subjective symptoms, and to present forward realistic and effective prevention measures by showing the risk of cumulative trauma disorders, objecting the production factory of a domestic riding automobile assembly shop, by estimating in the aspect of human-engineering through the analysis of risk factor being a cause of cumulative trauma disorders. Methods : For this study, I investigated work type and on-duty hours, breathing time, and subjective symptoms of cumulative trauma disorders through questionnaire, objecting the workers in press. car body, coating, and outfit factory. Results : As a result of research, 81.2% of workers were in the physical burden due to present working, and the highest prevalence by part of body is an waist. The higher a rule score, The higher the number of workers complaind for working intensity, and the higher age work duration, tool used time, the higher prevalence of subjective symptoms by part of body. The number of workers complaind subjective symptom for treatment is the highest in drugstore.

• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.11
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• pp.1696-1706
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• 2009

Nonwoven fabrics have been widely used in various fields that include household, industrial, agricultural, medical goods, especially in the automobile industry. In this study, eco-friendly fiber materials were developed and investigated as a substitute material for polyester fibers in nonwovens. To make plant fiber bundles, stems of Indian mallow (IM), and Kuzu vine (KV) were retted; in addition, the non-cellulose component was partially removed. Plant fiber bundles and polyester fibers (P) were blended and needle punched to produce nonwovens. Five kinds of nonwovens were manufactured: P100 (Polyester 100%), IM10 (IM 10% and Polyester 90%), IM20 (IM 20% and Polyester 80%), KV10 (KV 10% and Polyester 90%), and KV20 (KV 20% and Polyester 80%). The color values, surface appearance, tensile strength, elongation, tear strength, abrasion strength, flexstiffness, moisture regain, water or oil absorbency, and static electricity of manufactured nonwovens are investigated. As the blended ratios of IM or KV increased, the brightness of nonwovens decreased compared to that of polyester 100%. Tensile strength, tear strength, abrasion strength, and flexstiffness of IM10 as well as KV10 were higher than those of P100, IM20, and KV20, resulting from the influence of the structure and properties of nonwoven fibers. Moisture regain and water or oil absorbency increased, while static electricity decreased in proportion to the amount of plant fibers. IM or KV and polyester blended nonwovens showed improved properties over P100 that could be substituted for P100 as a novel material for textiles.

• Journal of the Korean Institute of Gas
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• v.17 no.2
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• pp.70-77
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• 2013

The present study has been carried out to analyze the effect of steam hammering on the steam piping system including the final superheater, the high pressure turbine, check valve and the first reheater by sudden stoping of main stop valve in a power plant. For the present steam hammering analysis, the well known Flowmaster software has been used to model the steam piping system and the time dependent characteristics of pressure and steam mass flow rate has been conducted. Using the result of the unsteady pressure and steam mass flow rate, the forces acting on the elbows in the piping system has been derived. From the present analysis, it has been elucidated that the elbow just before the main stop valve and the elbow near the connection pipe between bypass pipe and check valve had the largest force among the elbows in the steam piping system. The structural safety diagnostics study on the elbow and the supporting structures of the steam piping system of a power plant will be conducted in the future by the present results of the forces acting on the elbow.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.357-363
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• 2009

This paper deals with the Filtered-x Least Mean Square algorithm for a active vibration control in vehicle vibration reduction. Before applying the proposed FxLMS algorithm to automobile, the performance of the FxLMS algorithm is simulated using sensor data of a vehicle. The FxLMS algorithm requires that reference signal be a representation of disturbance signal and the plant model be incorporated into the computation path. To this end, The system identification is carried out to obtain the plant model based on the measurement results. A tachometer signal is used as reference signal. The FxLMS control algorithm is first tested using simulation and applied to a vehicle. Experimental results show that the proposed control algorithm can reduce vibration level in a short period of time.

• Transactions of the Korean hydrogen and new energy society
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• v.26 no.1
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• pp.64-70
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• 2015

Organic Rankine cycle (ORC) is an useful cycle for power generation system with low temperature heat sources ($80{\sim}400^{\circ}C$). Since the boiling point of operating fluid is low, the system is used to recover the low temperature heat source of waste heat energy. In this study, a ORC with R134a is applied to recover the waste energy of condenser of coal fired power plant. A system model is developed via Thermolib$^{(R)}$ under Simulink/MATLAB environment. The model is composed of a refrigerant heat exchanger for heat recovery from coal fired condenser, a drum, turbine, heat exchanger for ORC heat rejection, storage tank, water recirculation pump and water drip pump. System analysis parameters were heat recovery capacity, type of refrigerants, and types of turbines. The simulation model is used to analyze the heat recovery capacity of ORC power system. As a result, increasing the overall heat transfer coefficient to become the largest of turbine power is the most economical.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.474-477
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• 2002

Hearing loss caused by exposure to industrial machine noise results in devastating disability that is mostly preventable. And recent researches indicate that the noise may also induce hypertension and cardiovascular disease. In addition the sleep polygraph provides many indicators of sleep disturbance by the noise. In this paper we make an analysis on ball bearing machine noise, a kind of the industrial noise. The analysis of Its power spectrum is based on FFT(Fast Fourier Transform). And then the spectral results of the noise are compared with that of the spectrum for an auditory signal. The signal is measured from the pronunciation of two Koreans. Finally we suggest the most important stratagem to prevent the noise for worker's health and efficiency.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.6 no.4
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• pp.89-95
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• 1997

Welding technique is widely applied to general industry such as pressure vessel for chemical plant, pipe system, heavy industry, and automobile. There are some points which must be considered when robot system is used in welding automation process for productivity improvement. Welding quality is governed by heat input, and this quantity can be different according to shape, property, and thick of material . For desired heat input , weld input parameters such as welding voltage, current, and welding velocity must be determined with those consideration. Until now these parameters have been determined mainly by experience of operator. In this study, the size of welding zone was predicted by fuzzy rules were constructed from the relation between welding variables and weld pool size. Inverse model method which welding control input for welder is determined with optimum voltage and current by fuzzy controller is validatied by computer simulation.

• Laser Solutions
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• v.1 no.1
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• pp.11-17
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• 1998

The electron beam welding system has the advantages of the high power density, narrow welding section, and small thermal distortion of a workpiece. Recently, the electron beam welding system is widely used to the airplane engineering, nuclear power plant, and automobile industry. In the present paper, the structural analyses on the vacuum chamber of the electron beam welding system are performed by the F.E.M. analysis. The stiffening characteristics on the geometric shape, stiffener height and stiffener span are investigated. The deflection of the stiffened vacuum chamber under pressure is minimized by longitudinal and transverse stiffeners which are continuous in both direction.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.6 no.3
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• pp.92-97
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• 2007

The overlay welding the automobile where the durability is demanded, it is used in the vessel engine valve, plant valve and pump parts. Cause of damage public opinion one what is thought is the fatigue load due to the opening and shutting operation right time repetition of the engine valve. The damage cause of the engine valve or explanation of destruction mechanism is very difficult. The research which it sees to make clear a overlay welding of Co-alloy by Plasma Transferred Arc Weld Surfacing Process reconsideration fatigue crack initiation and fatigue crack growth mechanism at high temperature.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.5
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• pp.108-115
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• 2000

This paper presents a variant type process planning system for machining of dies for auto-body production. Through the analysis of dies and their manufacturing processes, the authors categorized the press dies into 15 groups according to the similarity of machining features. After critically reviewing current manufacturing procedures, a standard process plan was defined for each group. The authors present MP3D the process planning system built on the standard process plan database, and show how they apply it at the die manufacturing plant of an automobile company. MP3D is expected to reduce major losses in machining such as reworking caused by mistakenly uncut features and eventually to help to accumulate the knowledge of operators. The operation sheet MP3D produces is also used in monitoring the progress of manufacturing of dies. This paper explains the whole development cycle of a process planning system from process analysis to application so that it can help readers to develop and apply a process planning system to their machine shops.