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Assessment of the performances of a heat exchanger in a light helicopter

  • Carozza, Antonio
    • Advances in aircraft and spacecraft science
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    • v.2 no.4
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    • pp.469-482
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    • 2015
  • This study has the aim to develop a numerical design regarding the position and the inner performances of a heat exchanger in a light helicopter. the problem was to find first of all the best position of the heat exchanger inside the engine vane in order to maximize the air flow rate capable to pass through the heat exchanger section. It is to be said that the only air contribution in the vane comes from the opening present in the roof under the main rotor. The design has been performed by means of the commercial code Fluent and using the well known grid generator ICEM CFD. Different positions are first investigated so to establish the best one. Subsequently, different areas of the opening on the roof have been considered in order to maximize even more the flow rate in the heat exchanger that was not sufficient based on the first guess of velocity, as aforementioned. At the end interesting design results are presented and discussed by contours of fields and values.

Effect of Glumate on the Blood Concentrations of Ethanol in Healthy Adults (정상 성인에 있어서 미배아 발효액 (Glumate)이 에탄올의 혈중농도에 미치는 영향)

  • 김영철;박성호;이명걸
    • YAKHAK HOEJI
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    • v.37 no.5
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    • pp.549-553
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    • 1993
  • The extracts fermented of rice germ are called GMT (Glumate) which is a main ingredient of Condition$^{\circledR}$. It has been reported that GMT reduced the blood concentrations of alcohol in heathy adults. The purpose of the study is to examine the effect of GMT on blood concentrations of ethanol and on heart rate increase induced by ethanol. GMT was administered orally to 15 healthy adults before (10 min) and after (1 h) ethanol ingestion. The oral administration of GMT before (10 min) and after (1 h) ethanol ingestion reduced the area under the blood concentration of ethanol-time curve (p<0.12) and tended to inhibit the ethanol-induced heart rate increase.

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A Study on Dynamic Scheduling in Flexible Manufacturing System Environment (유연생산시스템 환경 하에서의 동적 일정계획에 관한 연구)

  • Lee Sang-Wan;Kim Hae-Sic;Cho Sung-Youl
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.27 no.2
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    • pp.17-23
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    • 2004
  • Changes in manufacturing system are those that occur during production and cause the systems to behave unpredictably. So scheduling problem in this dynamic Industrial environments is very complex. The main concept of this dissertation is to continuously monitor a manufacturing system status(Rate of Prior Job, Rate of Large Job, Rate of Shortest due date Job, Job Interval Time) and detect or predict a change so that scheduling system will react by modifying production schedule(dispaching rule) to lessen the effects of this change.

Evaluation of Engine Lubrication System for Adapting Variable Cam Timing System (VCT탑재를 위한 엔진윤활시스템 평가)

  • Yun Jeong-Eui
    • Tribology and Lubricants
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    • v.22 no.1
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    • pp.14-19
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    • 2006
  • VCT(Variable Cam Timing) system is one of very useful engine components to improve fuel economy and overcome emission regulation etc. In order to adapt the VCT to a base engine, many design mod ifications in the mechanical and lubrication fields are required. Especially, because the VCT performance itself depends on supplied oil flow rate and pressure, it is very important to evaluate the engine lubrication system in a viewpoint of supplied oil flow rate and pressure. In this paper, unsteady transient flow network analysis on the engine oil circuit system was carried out to do this.

Application of Ultrasounds for the Removal of Chlorobenzene and Chlorinated Phenols in Water (Chlorobenzene 및 Chlorinated Phenol류의 분해에 미치는 초음파의 응용)

  • 우영억;황규탁
    • Journal of environmental and Sanitary engineering
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    • v.15 no.4
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    • pp.35-43
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    • 2000
  • Aqueous solutions of chlorobenzene and chlorinated phenols were exposed to 200kHz ultrasound with a power of $6.0W/\textrm{cm}^2$ per unit volume on sonochemical reactor under ambient temperature and pressure conditions. The concentration of chlorobenzene and chlorinated phenols decreased with ultrasound, indicating first-order kinetics. Degradation rate constants are calculated from the slope of plots. The order of the rate constants is as follows : 2-chlorphenol(2-CP)$\leq$ 4-chlorophenol(4-CP)<3-chlorophenol(3-CP)$5.63~9.96({\times}10^{-2})min^{-1}$ under argon. The degradation was suppressed by the addition of t-BuOH and the suppressed yield was agreed with their reactivity for hydroxy radical. The main products of these systems were formic acid, acetic acid, small amount of methane and inorganic carbon forms as carbon dioxide, carbon monoxide in sonolysis of chlorinated phenols, and also these results agreed with change of TOC.

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A Study on the Characteristics of Cathodic Protection by Al-Alloy Sacrificial Anode in Marine Environment (해양환경중에서 A1-합금희생양극에 의한 음극방식특성)

  • 이연호
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.28 no.1
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    • pp.53-60
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    • 1992
  • In this study, cathodic protection experiment was carried out by Al-alloy sacrificial anode in marine environments which have specific resistance($\rho$) if 25~7000$\Omega$.cm and investigated protection potential, current density and loss rate of Al-alloy sacrificial anode. The main results resistance($\rho$) of 400$\Omega$.cm, the cathodic protection potential appears high about-720 mV(SCE). But below specific resistance($\rho$) of 300$\Omega$.cm, the cathodic protection potential appears low about-770 mV(SCE) and simultaneously, cathode is protected sufficiently. 2) The loss rate of Al-Alloy sacrificial anode became large with decreasing specific resistance and increasing the ratio(A sub(c)/A sub(a) of bared surface area of anode and cathode. 3) The loss rate of Al-alloy sacrificial anode(w) to the mean current density of anode(i) is as follows. w=ai+b (a, b : experimental constants)

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Study on the Corrosion Charactristics and its Corrosion Protection of Steel Fishing Banks (강제어촌의 부식특성과 그 방식에 관한 연구)

  • Lim, Uh-Joh;Lee, Jong-Rark
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.28 no.2
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    • pp.216-227
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    • 1992
  • The corrosion rate, behavior of corrosion fatigue and characteristic of cathodic protection for SB41 were investigated by corrosion and corrosion control tests in seawater at laboratory and coast. The main result obtained are as the following; 1) The corrosion rate of base metal (BM) is about 28-37 mg/dm super(2) day in seawater of coast. 2) The correlation between the stress intensity factor range $\Delta$K and crack propagation rate da/dN for weldment follows paris' rule in seawater : da/dN=C($\Delta$K) super(m) where m is the slope of the correlation, and is 2.02 for BM and 1.75 for heat affected zone (HAZ) respectively. 3) The corrosion sensitivity of HAZ is more sensitive than that of BM under the low region of $\Delta$K. 4) With increase of bared surace area of cathode, cathodic protection potential is increased sharply.

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Channel-Adaptive Rate Control for Low Delay Video Coding

  • Lee, Yun-Gu
    • IEIE Transactions on Smart Processing and Computing
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    • v.5 no.5
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    • pp.303-309
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    • 2016
  • This paper presents a channel-adaptive rate control algorithm for low delay video coding. The main goal of the proposed method is to adaptively use the unknown available channel bandwidth while reducing the end-to-end delay between encoder and decoder. The key idea of the proposed algorithm is for the status of the encoder buffer to indirectly reflect the mismatch between the available channel bandwidth and the generated bitrate. Hence, the proposed method fully utilizes the unknown available channel bandwidth by monitoring the encoder buffer status. Simulation results show that although the target bitrate mismatches the available channel bandwidth, the encoder efficiently adapts the given available bandwidth to improve the peak signal-to-noise ratio.

Characteristics of Hodgkin Lymphoma in a Defined Group of Iranian Pediatric Patients

  • Baharvand, Maryam;Mortazavi, Hamed
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.13
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    • pp.5167-5169
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    • 2014
  • This study was conducted to describe the characteristics of Hodgkin lymphoma in Iranian children. In a referral center for pediatric oncology (Mofid Hospital) in Tehran, patient data over a 10-year period were retrieved and recorded accordingly. Among 82 cases, 73.2% were male, 26.8% were female, and 70.7% were 5-9 years old. About 40% of patients were in stage III and 42.7% had systemic signs. Cervical nodes were commonly involved (91.5%). The most frequent histological subtype was mixed cellularity. The main hematological features were anemia (47.6%), lymphopenia (20.7%), and eosinophilia (8.7%). Survival rate was 72%, and 8.4% of patients were deceased. A 3% recurrence rate was observed in our patients. A significant relationship was found between the stage of disease and systemic signs (P<0.0005, ${\chi}^2$). Despite diagnosis of Hodgkin lymphoma in many children in Iran being made in higher stages, the mortality rate is relatively low.

The Effect of Temperature on Corrosion of Absorption Refrigeration Systems Using $LiBr-H_2O$ Working Fluids ($LiBr-H_2O$계 흡수식냉동기의 부식에 미치는 온도의 영향)

  • 임우조;정기철
    • Journal of Advanced Marine Engineering and Technology
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    • v.26 no.1
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    • pp.125-131
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    • 2002
  • This paper was studied on the effect of temperature on corrosion of absorption refrigeration systems using $LiBr-H_2O$ working fluids. In the fresh water and 62 % lithium bromide solution at $70^{\circ}C$, polarization test of SS 400, Cu(C1220T-OL) and Al-Ni bronze was carried out. And polarization behavior, polarization resistance characteristics, corrosion rate(mmpy) and corrosion sensitivity of materials forming absorption refrigeration systems was considered. The main results are as following: (1) As the experimental temperature increase, the change of corrosion rate of Al-Ni bronze become duller than SS 400 and Cu in 62% lithium bromide solution. (2) According as corrosion environment is changed from fresh water to 62% lithium bromide solution, potential change of Cu and Al-Ni bronze become less noble than SS 400. (3) The corrosion sensitivity of Al-Ni bronze was duller than that of Cu and SS 400 in 62% LiBr solution.