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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society of Marine Engineering
Journal Basic Information
Journal DOI :
Korean Society of Marine Engineers
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Volume & Issues
Volume 19, Issue 4 - Aug 1995
Volume 19, Issue 3 - Jun 1995
Volume 19, Issue 2 - Apr 1995
Volume 19, Issue 1 - Feb 1995
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Vacuum Cooling System by the Various Ejectors
Journal of the Korean Society of Marine Engineering, volume 19, issue 4, 1995, Pages 1~6
Recently, outstanding progresses have been made in food industry, in all the processes involved in the conversion of raw materials into food products. This article describes two kinds of coolers for processing uncooded foor, namely vacuum coolers capable of rapidly cooling decomposing bacteria down to their critical temperature, and also cooling equipment for fresh vegetables based on the same principle as the vacuum cooler.
Vacuum Cooling System and Their Use
Journal of the Korean Society of Marine Engineering, volume 19, issue 4, 1995, Pages 7~16
This article describes the working prnciple, structure and main characteristics of vacuum coolers for vegetables, and gives concrete examples of vacuum coolers that srebeing put to practical use. In particular, newly-developed cavuum coolers with cold storage, utilizing night-time electricity, are focused upon. Processing plants for vegetables, cold-storage rooms and vacuum cooling devices were investigated as possible application of vacuum cooling technology.
A Study on the Heat Transfer Characteristics of Liquid Droplet Radiator for Air Conditioning
Journal of the Korean Society of Marine Engineering, volume 19, issue 4, 1995, Pages 17~26
In general existing air conditioning devices, which are carried out by convection heat transfer, are very popular compared with the radiation type air conditioning devices. But perconal convection tpe air conditioning units are unuseful air conditioning type because it handles amount of surrounded air to meet the temperature and humidity. In this view, this study is intended to develope personal dir conditioning units using a radiation type radiator. Liquid Droplet Radiator(L.P.R.) radiates the energy by means of thermal radiation. Radiative energy from L.P.R. is the infrared rays which heat the objects without lose of energy. It is a desirable heating method for the local area within the large room. In this study, the analysis uses the Monte Carlo methd to predict the temperature distribution in the droplet sheet and the net heat flux from the L.D.R.. And for this study and experiment was carried out to analyse the radiative and convective heat transfer characteristics in the L.D.R.. And the experiment was investigated the effects of inlet temperature, feed rate, optical thickness and droplet diameter on heat transfer characteristics of L.D.R.. The obtained results from the numerical and experimental studies of L.D.R. were as follows ; (1) The heat flux of L.D.R. was effected by extinction coefficient of droplet sheet, optical thickness and droplet temperature, surface area and emissivity of the droplet. And it was increased with the temperature, feed rate and optical thickness, on the other hand decreased with increasing of droplet diameter. (2) The experimental results for heat flux was ecalucted below 20% than that of the numerical solution by Monte Carlo method, but the tendency of the variation shows relatively good agreement.
Numerical Ananlysis on the Tubulent Flow and Heat Transfer in the Tunnel Laminar Flow Type Clean Room(1)
Journal of the Korean Society of Marine Engineering, volume 19, issue 4, 1995, Pages 27~33
The turbulent flow and heat transfer in the tunnel laminar flow type clean room is investigated by a numerical simulation. The model clean room is assumed to be a rectngular
, in which a worktable of 0.75m hight, and 1.5m or 3m long at the floor. Major parameters are the inlet flow velocity, inlet hole size and worktable surface distance. The mean Nusselt number is increased by increasing Reynolds number and can be expressed by the correlation equation.
A Study on the Effects of Reynolds Number and Damkohler Number in the Structure of Premixed Turbulent Flames
Journal of the Korean Society of Marine Engineering, volume 19, issue 4, 1995, Pages 34~41
The structure of premixed tubulent flames in a constant-volume vessel was investigated using a schlieren method and microprobe method. The schlieren method was used to observe the flame structure qualitatively. The microprobe method, which detects a flamelet by detecting its flame potential signal, was used to investigate the deeper flame structure behind the flame front. The flame potential signal having one to six peaks was obtained in the case of turbulent flames, each of them being regarede as a flamelet existing in the flame zone. Based on this consideration, the flame propagation speed, the thickness of the flame zone, the number of flamelets and the separation distance between adjacent flamelets in the flame zone were measured. Moreover, the thickness of flamelet which could not be attempted in the conventional electrostatic probe method was also investigated. The experimental results of this work suggest the existence of "reactant islands" in the reaction zone, and show that the averaged number of flamelets increases with an increase in the turbulence intensity and/or a decrease in the Damkohler number. The mean thickness of flamelet in the case of turbulent flames was found to be about two times compared to laminar values.ar values.
The effect of welding methods on the stress corrosion behavior of the welded austenitic stainless steel
Journal of the Korean Society of Marine Engineering, volume 19, issue 4, 1995, Pages 42~50
To study the effect of welding methods on the Stress Corrosion Cracking (SCC) behavior of welded AISI type 316L and 304 austenitic stainless steel, the Slow Strain Rate Technique(SSRT) has been adopted in the boiling 45 wt%
solution. The results are as follows. 1) Welded sections are more susceptible than base metal in SCC, and the rank of SCC, and the rasistance in welding method is TIG, MIG,
and ARC. 2) The Ultimate tensile strength(UTS) and the strain of both base metal and welded joint are reduced as decreasing extension rate. 3) The SCC resistance of 316L base metal and welded sections are superior than that of 304. 4) The tendency of pitting and the SCC suseptibility are agreed well, and the SCC site is welded deposit section in 316L whereas HAZ in 304.
Processing and physical properties of composite materials for the brake lining of the automobile
Journal of the Korean Society of Marine Engineering, volume 19, issue 4, 1995, Pages 51~60
Along with the rapid development of automobile industry in this country the necessity of high quality braking material is ever increased to maintain the comfortness as well as the safety the passengers. Asbestos-based friction materials are banned in the developed countries because of their cancer-inducing effect. This study focuses on the development of non-acbestos friction material with acceptable properties such as wear resistant high temperature endurant and low-noise enducing. We have all the intermediate test results indicating the contribution of each additives. These are qualitatively analyzed. Manufacturing processes such as opening of the kevlar and degasing at elevated temperature is equally important to attain proper level of friction quality.
A study on the development of thin-walled metal bearing for the large-sized slow speed diesel engines.
Journal of the Korean Society of Marine Engineering, volume 19, issue 4, 1995, Pages 61~71
Nowadays the thin-walled metal bearing, which is made seperately from the bearing housing and has the ratio of wall thickness/bearing diameter being less than 1/30, are used in many newly developed large-sized slow speed diesel engines for the purpose of upgarding lubication performance and easy maintenance according to the trends of increasing output per cylinder and lowering engine speed. The type of this bearing has been used generally in many small-sized high speed engines applied for automobile, high speed craft and industrial power generation systems since 1950s. But the tranditional thick-walled bearings, whice are linned white metal on the bearing housing directly, have been installed on the large and slow speed engines until 1990s due to the easy manufacturing procedures. In this study we have calculated optimum dimensions of the metal bearing, fabricated special zigs for crush measurement, model test machine, 2 sets of specimens.(crosshead pin bearing,
818*552*20mm) for B & W 6S70MC(20, 940*88rpm), and evaluated metal constact phenomena of white metal, its friction coefficient, temparature rise through the model test and field performance test.
The development of fuzzy reasoning tool for the support design of servo system
Journal of the Korean Society of Marine Engineering, volume 19, issue 4, 1995, Pages 72~78
The diffusion of fuzzy logic techniques into real applications requires specific software supports which save development time and reduce the programming effort. But we has been lack of a tool devoted to support the design of fuzzy controllers. In this paper, on the basis of the general fuzzy set and .alpha.-cut set decomposition of fuzzy sets, a set of fuzzy reasoning tool(FRT) devoted to support the design of fuzzy dontroller for servo systems is developed. The major features of this tool are: 1) It supports users to analyze fuzzy ingerence status based on input deta and expected results by three-D graphic display. 2) It supports users to prepare input data and expected result. 3) It supports users to tuned scaling factor of membership functions, rules and fuzzy inference. The paper shows how the suggested design tools are suitable to give a consistent answer to the tuning of fuzzy control system. This FRT is expected to exert good performance and devoted to support which the design of fuzzy controller is illustrated in the servo systems.
The Current and Power Waveform Improvement of an AC Motor with Low Pass LC Filter Driven by a Digital Bridge Inverter(II)
Journal of the Korean Society of Marine Engineering, volume 19, issue 4, 1995, Pages 79~91
Recently, the AC motor which has a simple structure and needs less maintenance has become to be used frequently as a servomotor for position control in the automatic control field. This paper concerns with a method to improve the current and power waveforms of an AC motor, and the current waveforms and 3
power waveforms are analyzed by FFT under verious running conditions. The system is composed of a digital bridge inverter, low pass LC filter, and 3
AC motor. Through the computer simulations and experiments, it is confirmed that current waveforms and
power waveforms con by improved by utilizing the high order low pass LC filter than that of lower order.