• Title/Summary/Keyword: Set-point Temperature

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Controlling Noxious Animal Odours : An Imperative at the Rural-Urban Interface - Review -

  • Jiang, J.K.;Sands, J.R.
    • Asian-Australasian Journal of Animal Sciences
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    • v.12 no.4
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    • pp.633-641
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    • 1999
  • Reaction by neighbours to odours is increasingly affecting operations of existing animal farming operations and may adversely constrain the further development of the animal production industry in some parts of Australia. It is critical that the scale of such odour impact on the rural-urban interface be estimated to provide useful information both for environmental protection and animal farming operations. Furthermore, the information can be used to modify odour reduction strategies as economic conditions change. The Centre for Water and Waste Technology at The University of New South Wales has developed a comprehensive set of odour control techniques in the course of its research and development effort over the past eight years. Techniques have been developed for odour sampling at point, area and volume sources, monitoring environmental parameters such as ventilation rate, shed temperature, shed humidity, litter water content and ambient meteorological condition, olfactometry and odour dispersion modelling. The work has paved the way for the establishment of odour reduction strategies based on best environmental management practice and advanced odour abatement technologies.

A study with more probability for predicting the quantitative severity of fire occurance in department stores (백화점 화재 발생의 확률적 접근에 의한 심각성의 정량적 예측)

  • 구진영;김광열
    • Fire Science and Engineering
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    • v.12 no.1
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    • pp.15-21
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    • 1998
  • In this research, we studied reach the conclusion with more probability for predicting the severity which based on fire cases in domestic department stores for last 30 years. Considering the number of yearly fire cases in department stores and the cost of damage, we set the risk level. Moreover, this research shows the severity of fire in department stores through its scenario applying to FPETOOL program which NIST in USA has developed. By the result of FPETOOL program operation, we could acquired information about the time reaching the point where people are in danger in temperature, smoke layer and gas concentration. When a fire breaks out in a department store, a great loss of property and life is significant, as well as the potential risk is awfully considerable. Therefore, we should prevent a five from occuring.

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Humidity dependent size control of local anodic oxidation on graphene using Atomic Force Microscope (원자힘 현미경의 습도 조절에 의한 그래핀 국소 산화)

  • Ko, Seoknam;Lee, Seong jun;Son, Maengho;Ahn, Doyeol;Lee, Seung-Woong
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2014.11a
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    • pp.226-227
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    • 2014
  • We demonstrate nanoscale local anodic oxidation (LAO) patterning on few layer graphene using atomic force microscope (AFM) at room temperature and normal atmosphere. We focus on the humidity dependency in nanoscale oxidation of graphene. The relationship between the oxidation size and the AFM setting values, such as set point, tip speed, and humidity are observed. By changing these values, proper parameters were found to produce features on demand size. This technique provides an easy way to form graphene oxide lithography without any chemical resists. We have obtained oxidation size down to 50-nm with 6-nm-height oxide barrier line with $0.1{\mu}m/s$ tip scanning speed and micrometer size symbols on a graphene flake. We attribute the bumps to local anodic oxidation on graphene surface and combination of oxygen ions into the graphene lattice.

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Theoretical Analysis and Study of Design of Autothermal Reformer for Use in Fuel Cell (연료전지용 열분해 개질기의 이론해석 및 설계연구)

  • Kang, Il-Hwan;Kim, Hyung-Man;Choi, Kap-Seung;Wang, Hak-Min
    • 한국연소학회:학술대회논문집
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    • 2005.10a
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    • pp.58-63
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    • 2005
  • As fuel cells approach commercialization, hydrogen production becomes a critical step in the overall energy conversion pathway. Reforming is a process that produces a hydrogen-rich gas from hydrocarbon fuels. Hydrogen production via autothermal reforming (ATR) is particularly attractive for applications that demand a quick start-up and response time in a compact size. However, further research is required to optimize the performance of autothermal reformers and accurate models of reactor performance must be developed and validated. The design includes the requirement of accommodating a wide range of experimental set ups. Factors considered in the design of the reformer are capability to use multiple fuels, ability to vary stoichiometry, precise temperature and pressure control, implementation of enhancement methods, capability to implement variable catalyst positions and catalyst arrangement, ability to monitor and change reactant mixing, and proper implementation of data acquisition. A model of the system was first developed in order to calculate flowrates, heating, space velocity, and other important parameters needed to select the hardware that comprises the reformer. Predicted performance will be compared to actual data once the reformer construction is completed. This comparison will quantify the accuracy of the model and should point to areas where further model development is required. The end result will be a research tool that allows engineers to optimize hydrogen production via autothermal reformation.

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Development of Variable Duty Cycle Control Method for Air Conditioner using Artificial Neural Networks (신경회로망을 이용한 에어컨의 가변주기제어 방법론 개발)

  • Kim, Hyeong-Jung;Doo, Seog-Bae;Shin, Joong-Rin;Park, Jong-Bae
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.55 no.10
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    • pp.399-409
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    • 2006
  • This paper presents a novel method for satisfying the thermal comfort of indoor environment and reducing the summer peak demand power by minimizing the power consumption for an Air-conditioner within a space. Korea Electric Power Corporation (KEPCO) use the fixed duty cycle control method regardless of the indoor thermal environment. However, this method has disadvantages that energy saving depends on the set-point value of the Air-Conditioner and direct load control (DLC) has no net effects on Air-conditioners if the appliance has a lower operating cycle than the fixed duty cycle. In this paper, the variable duty cycle control method is proposed in order to compensate the weakness of conventional fixed duty cycle control method and improve the satisfaction of residents and the reduction of peak demand. The proposed method estimates the predict mean vote (PMV) at the next step with predicted temperature and humidity using the back propagation neural network model. It is possible to reduce the energy consumption by maintaining the Air-conditioner's OFF state when the PMV lies in the thermal comfort range. To verify the effectiveness of the proposed variable duty cycle control method, the case study is performed using the historical data on Sep. 7th, 2001 acquired at a classroom in Seoul and the obtained results are compared with the fixed duty cycle control method.

A Numerical Study on the Transmission of Thermo-Acoustic Wave Induced by Step Pulsed Heating in an Enclosure (제한공간내 펄스가열에 기인한 열음향파의 전달특성에 관한 수치적 연구)

  • 황인주;김윤제
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.14 no.11
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    • pp.914-922
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    • 2002
  • Thermo-acoustic waves can be thermally generated in a compressible flow field by rapid heating and cooling, and chemical reaction near the boundary walls. This mechanism is very important in the space environment in which natural convection does not exist. Also this may be a significant factor for heat transfer when the fluids are close to the thermodynamic critical point. In this study, the generation and transmission characteristics of thermo-acoustic waves in an air-filled confined domain with two-step pulsed heating are studied numerically. The governing equations are discretized using control volume method, and are solved using PISO algorithm and second-order upwind scheme. For the purpose of stable solution, time step was set to the order of $1\times10_-9s,\;and\;grids\;are\;50\times2000$. Results show that temperature and pressure distributions of fluid near the boundary wall subjected to a rapid heating are increased abruptly, and the induced thermo-acoustic wave propagates through the fluid until it decays due to viscous and heat dissipation. Pressure waves have sharp front shape and decay with a long tail in the case of step heating, but these waves have sharp pin shape in the case of pulsed heating.

Fuzzy Inference-based Quantitative Estimation of Environmental Affecting Factor For Performance-based Durability Design of RC Structure Exposed to Salt Attack Environment (염해 환경에 노출된 RC 구조물의 내구성능설계를 위한 퍼지 추론 기반 환경영향지수의 산정)

  • Do Jeong Yun;Song Hun;Soh Seung Young;Soh Yang Seob
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.05b
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    • pp.237-240
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    • 2005
  • As a part of the effort for improving the durability design based on a set of the deem-to-satisfy specifications, it is important and primary to quantitatively identify the environmental impact to a target reinforced concrete structure. In this work, an effort is made to quantitatively calculate the environmental affecting factor with using a fuzzy inference that it indicates the severity of environmental impact to the exposed reinforced concrete structure or member. This system is composed of input region, output region and rule base. For developing the fuzzy inference system surface chloride concentration{chloride), cyclic degree of wet and dry(CWD), relative humidity(RH) and temperature (TEMP) were selected as the input parameter to environmental affecting factor(EAF) of output parameter. The Rules in inference engine are generated from the engineering knowledge and intuition based on some international code of practises as well as various researcher's experimental data. The devised fuzzy inference system was verified comparing the inferred value with the investigation data, and proved to be validated. Thus it is anticipated that this system for quantifying EAF is certain to be considered into the starting point to develop the performance-based durability design considering the service life of structure.

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Density Functional Theoretical Study on Intermolecular Interactions of 3,6-Dihydrazino-1,2,4,5-tetrazine Dimers

  • Hu, Yin;Ma, Hai-Xia;Li, Jun-Feng;Gao, Rong;Song, Ji-Rong
    • Bulletin of the Korean Chemical Society
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    • v.31 no.10
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    • pp.2897-2902
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    • 2010
  • Seven fully optimized geometries of 3,6-dihydrazino-1,2,4,5-tetrazine (DHT) dimers have been obtained with density functional theory (DFT) method at the B3LYP/$6-311++G^{**}$ level. The intermolecular interaction energy was calculated with zero point energy (ZPE) correction and basis set superposition error (BSSE) correction. The greatest corrected intermolecular interaction energy of the dimers is $-23.69\;kJ{\cdot}mol^{-1}$. Natural bond orbital (NBO) analysis is performed to reveal the origin of the interaction. Based on the vibrational analysis, the changes of thermodynamic properties from the monomers to dimer with the temperature ranging from 200.0 K to 800.0 K have been obtained using the statistical thermodynamic method. It was found that the hydrogen bonds dominantly contribute to the dimers, while the binding energies are not only determined by hydrogen bonding. The dimerization process can not occur spontaneously at given temperatures.

Experimental study for optimizing the thermal regulating system with phase change material on the photovoltaic panel (태양광패널 온도제어를 위한 PCM시스템 최적화에 관한 실험적 연구)

  • Lee, Hyo-Jin;Chun, Jong-Han
    • 한국태양에너지학회:학술대회논문집
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    • 2009.11a
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    • pp.273-278
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    • 2009
  • The experimental study is performed to investigate the optimum design of the system dissipating properly heat from the in-situ solar panel installed on site. For this purpose, six 12-Watts panels, which are set at the different conditions of the solar panels contained phase change material, changing the array of the aluminum fin and honeycomb at the back of the panel, are tested. PCM, which has $44^{\circ}C$ melting point, is chosen in this study. In order to enhance the thermal heat from the absorbed heat in PCM, finned aluminum plate is placed. Furthermore, Aluminum honeycomb is imbedded in the back container to find if it would improve the thermal conductivity of PCM. As a result, the solar panel, which is combined with honeycomb and outward fins with PCM instead of placing the fine inward, is showing the best performance in terms of controling panel temperature and efficiency.

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The Hyperthermic Effect of Nitric Oxide in Central Nervous System

  • Jung, Jae-Kyung;Sohn, Uy-Dong;Lee, Seok-Yong
    • The Korean Journal of Physiology and Pharmacology
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    • v.5 no.1
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    • pp.93-98
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    • 2001
  • The precise mechanism of set-point regulation in hypothalamus was not elucidated. Nitric oxide synthases(NOS) were detected in hypothalamus, however, the roles of NO in hypothalamus was not fully studied. So, we tested the effects of NO on body temperature because preoptic-anterior hypothalamus was known as the presumptive primary fever-producing site. NO donor sodium nitroprusside (SNP, 4 nmol, i.c.v.) elicited marked febrile response, and this febrile response was completely blocked by indomethacin (a cyclooxygenase inhibitor). But, ODQ (selective guanylate cyclase inhibitor, $50\;{\mu}g,$ i.c.v.) did not inhibit fever induced by SNP. The cyclic GMP analogue dibutyryl-cGMP $(100\;{\mu}g,\;i.c.v.)$ induced significant pyreses, which is blocked by indomethacin. $N^G-nitro-L-arginine$ methyl ester (L-NAME, non selective NOS inhibitor) inhibited fever induced by $interleukin-1{\beta}\;(IL-1{\bata},\;10\;ng,\;i.c.v.),$ one of endogenous pyrogens. These results indicate that NO may have an important role, not related to stimulation of soluble guanylate cyclase, in the signal pathway of thermoregulation in hypothalamus.

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