• Title/Summary/Keyword: $Q_C^{-1}$

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Effect of Boundary Layer Generated on the fin surfaces of a Compact Heat Exchanger on the Heat Transfer and Pressure Drop Characteristics (컴팩트형 열교환기의 핀 표면에서 발생하는 경계층이 열교환기의 전열 및 압력강하 특성의 변화에 미치는 영향에 관한 수치해석적 연구)

  • KIM Chul-Ho;Jung Ji-Yong
    • Journal of computational fluids engineering
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    • v.3 no.1
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    • pp.82-88
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    • 1998
  • As a par of a project related to the development of the design algorithm of a compact heat exchanger for the application of the electronic home appliances, the effect of the discreteness of the airflow boundary generated on the cooling fin surface on the heat transfer and pressure drop characteristics of the heat exchanger was studied numerically. In general, there are two critical design parameters seriously considered in the design of the heat exchanger; heat transfer rate(Q) and pressure drop coefficient(C/sub p/). Even though the higher heat transfer rate with lower pressure drop characteristics is required in a design of the heat exchanger, it is not an easy job to satisfy both conditions at the same time because these two parameters are phenomenally inversely proportional. To control the boundary layer thickness and its length along the streamline, the surface of the flat fin was modified to accelerate the heat transfer rate on the fin surface. To understand the effect of the discreted fin size(S/sub w/) and its location(S/sub h/) on the performance of the heat exchanger in the airflow field, the flat fin was modified as shown in Fig. 1. From this study, it was found that the smaller and more number of slits on the fin surface showed the higher energy diffusion rate. It means that the discreteness of the boundary layer is quite important on the heat transfer rate of the heat exchanger. On the other hand, if the fin surface configuration is very complex than needed, higher static pressure drop occurs than required in a system and it may be a reason of the induced aerodynamic noise in the heat exchanger.

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Flutter analysis of Stonecutters Bridge

  • Hui, Michael C.H.;Ding, Q.S.;Xu, Y.L.
    • Wind and Structures
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    • v.9 no.2
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    • pp.125-146
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    • 2006
  • Stonecutters Bridge of Hong Kong is a cable-stayed bridge with two single-column pylons each 298 m high and an aerodynamic twin deck. The total length of the bridge is 1596 m with a main span of 1018 m. The top 118 m of the tower will comprise structural steel and concrete composite while the bottom part will be of reinforced concrete. The bridge deck at the central span will be of steel whilst the side spans will be of concrete. Stonecutters Bridge has adopted a twin-girder deck design with a wide clear separation of 14.3 m between the two longitudinal girders. Although a number of studies have been conducted to investigate the aerodynamic performance of twin-girder deck, the actual real life application of this type of deck is extremely limited. This therefore triggered the need for conducting the present studies, the main objective of which is to investigate the performance of Stonecutters Bridge against flutter at its in-service stage as well as during construction. Based on the flutter derivatives obtained from the 1:80 scale rigid section model experiment, flutter analysis was carried out using 3-D finite element based single parameter searching method developed by the second author of this paper. A total of 6 finite element models of the bridge covering the in-service stage as well as 5 construction stages were established. The dynamic characteristics of the bridge associated with these stages were computed and applied in the analyses. Apart from the critical wind speeds for the onset of flutter, the dominant modes of vibration participating in the flutter vibration were also identified. The results indicate that the bridge will be stable against flutter at its in-service stage as well as during construction at wind speeds much higher than the verification wind speed of 95 m/s (1-minute mean).

Expression Characterization, Polymorphism and Chromosomal Location of the Porcine Calsarcin-3 Gene

  • Wang, Heng;Yang, Shulin;Tang, Zhonglin;Mu, Yulian;Cui, Wentao;Li, Kui
    • Asian-Australasian Journal of Animal Sciences
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    • v.20 no.9
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    • pp.1349-1353
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    • 2007
  • Calcineurin is a calmodulin dependent protein that functions as a regulator of muscle cell growth and function. Agents capable of interacting with calcineurin could have important applications in muscle disease treatment as well as in the improvement of livestock production. Calsarcins comprise a family of muscle-specific calcineurin binding proteins which play an important role in modulating the function of calcineurin in muscle cells. Recently, we described the first two members of the calsarcin family (calsarcin-1 and calsarcin-2) in the pig. Here, we characterized the third member of the calsarcin family, calsarcin-3, which is also expressed specifically in skeletal muscle. However, unlike calsarcin-1 and calsarcin-2, the calsarcin-3 mRNA expression in skeletal muscle kept rising throughout the prenatal and postnatal development periods. In addition, radiation hybrid mapping indicated that porcine calsarcin-3 mapped to the distal end of the q arm of pig chromosome 2 (SSC2). A C/T single nucleotide polymorphism site in exon 5 was genotyped using the denaturing high performance liquid chromatography (DHPLC) method and the allele frequencies at this locus were significantly different among breeds.

An Integrated Model of Static and Dynamic Measurement for Seat Discomfort

  • Daruis, Dian Darina Indah;Deros, Baba Md;Nor, Mohd Jailani Mohd;Hosseini, Mohammad
    • Industrial Engineering and Management Systems
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    • v.10 no.3
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    • pp.185-190
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    • 2011
  • A driver interacts directly with the car seat at all times. There are ergonomic characteristics that have to be followed to produce comfortable seats. However, most of previous researches focused on either static or dynamic condition only. In addition, research on car seat development is critically lacking although Malaysia herself manufactures its own car. Hence, this paper integrates objective measurements and subjective evaluation to predict seat discomfort. The objective measurements consider both static and dynamic conditions. Steven's psychophysics power law has been used in which after expansion; ${\psi}\;=\;a+b{\varphi}_s^{\alpha}+c{\varphi}_v^{\beta}$ where ${\psi}$ is discomfort sensation, ${\varphi}_s^{\alpha}$ is static modality with exponent ${\alpha}$ and ${\varphi}_v^{\beta}$ is dynamic modality with exponent ${\beta}$. The subjects in this study were local and the cars used were Malaysian made compact car. Static objective measurement was the seat pressure distribution measurement. The experiment was carried out on the driver's seat in a real car with the engine turned off. Meanwhile, the dynamic objective measurement was carried out in a moving car on real roads. During pressure distribution and vibration transmissibility experiments, subjects were requested to evaluate their discomfort levels using vehicle seat discomfort survey questionnaire together with body map diagram. From subjective evaluations, seat pressure and vibration dose values exponent for static modality ${\alpha}$ = 1.51 and exponent for dynamic modality ${\beta}$ = 1.24 were produced. The curves produced from the $E_{q.s}$ showed better $R_{-sq}$ values (99%) when both static and dynamic modalities were considered together as compared to Eq. with single modality only (static or dynamic only R-Sq = 95%). In conclusion, car seat discomfort prediction gives better result when seat development considered both static and dynamic modalities; and using ergonomic approach.

Effects of Dietary Metabolizable Energy and Lysine on CarcassCharacteristics and Meat Quality in Arbor Acres Broilers

  • Tang, M.Y.;Ma, Q.G.;Chen, X.D.;Ji, C.
    • Asian-Australasian Journal of Animal Sciences
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    • v.20 no.12
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    • pp.1865-1873
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    • 2007
  • An experiment was performed to evaluate the effects of dietary metabolizable energy (ME) and lysine on carcass characteristics and meat quality in Arbor Acres (AA) broilers from 1 to 56 days of age. A total of 2,970 1-d-old male broiler chicks were randomly allocated to nine dietary treatments (three ME levels in combination with three lysine levels), and dietary ME and lysine concentrations were formulated by varying corn, soybean meal, tallow, and L-lysine sulfate concentrations. Live body weight (BW), carcass weight (CW), dressing percent, breast muscle weight (BMW), yield of breast muscle, muscle color (CIE L*, a*, and b*), pH values 45 min and 24 h postmortem ($pH_{45}$, and $pH_{24}$), meat shear force value (SFV), and water loss rate (WLR) were evaluated. Results showed that live body weight and dressing percent increased (p<0.05) as dietary energy increased. Higher dietary lysine content improved breast muscle weight. Neither carcass weight nor yield of breast muscle was affected by dietary energy or lysine content. Higher ME increased the b* value (p = 0.067) and $pH_{24}$ value (p<0.05), whereas it decreased SFV (p<0.05) and WLR (p = 0.06). Only water loss rate was influenced (p<0.01) by dietary lysine, which was higher in broilers from the high lysine diet as compared to those from medium or low lysine diets. The $pH_{45}$ value and L* value of breast muscle were not affected by ME or lysine. Significant interaction of dietary ME and lysine was found on a* value of breast muscle. These results indicated that dietary ME and lysine had important effects on breast muscle growth and meat quality, however their effects were different. Different concentrations of dietary ME and lysine might be considered to improve meat quality.

Genomic Organization and Isoform-Dependent Expression Patterns of Wap65 genes in Various Tissues during Immune Challenges in the Mud Loach Misgurnus mizolepis

  • Kim, Yi Kyung;Cho, Young Sun;Lee, Sang Yoon;Nam, Yoon Kwon
    • Fisheries and Aquatic Sciences
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    • v.17 no.4
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    • pp.471-478
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    • 2014
  • Genomic organization, including the structural characteristics of 5'-flanking regions of two 65-kDa protein (WAP65) isoform genes associated with warm temperature acclimation, were characterized and their transcriptional responses to immune challenges were examined in the intestine, kidney and spleen of the mud loach (Misgurnus mizolepis; Cypriniformes). Both mud loach Wap65 isoform genes displayed a 10-exon structure that is common to most teleostean Wap65 genes. The two mud loach Wap65 isoforms were predicted to possess various stress- and immune-related transcription factor binding sites in their regulatory regions; however, the predicted motif profiles differed between the two isoforms, and the inflammation-related transcription factor binding motifs, such as NF-${\kappa}B$ and CREBP sites, were more highlighted in the Wap65-2 isoform than the Wap65-1 isoform. The results of qRT-PCR indicated that experimental immune challenges using Edwardsiella tarda, lipopolysaccharide or polyI:C induced the Wap65-2 isoform more than Wap65-1 isoform, although modulation patterns in response to these challenges were tissue- and stimulant-dependent. This study confirms that functional diversification between the two mud loach Wap65 isoforms (i.e., closer involvement of Wap65-2 in the acute phase of inflammation and innate immunity) occurs at the mRNA level in multiple tissues, and suggests that such differential modulation patterns between the two isoforms are related to the different transcription factor binding profiles in their regulatory regions.

On-line Surface Defect Detection using Spatial Filtering Method (공간필터법을 이용한 온라인 표면결함 계측)

  • Moon, Serng-Bae;Jun, Seung-Hwan
    • Journal of Navigation and Port Research
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    • v.28 no.1
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    • pp.43-49
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    • 2004
  • Defects inspection of commodities are very important with those design and manufacturing process and essential to strengthen the competitiveness of those. If on-line automatic defects detection is performed without damaging to products, the production cost shall be curtailed through the reducing man-power, economical management of Q.C(Quality Control). In this paper, it is suggested three spatial filtering methods which can extract the necessary information in case of defects being on the surface of object like iron plate. In addition, the dependence of filtering characteristics on parameters such as the pitch and width of slits is analyzed and the surface defect detection system is constructed. Several experiments were carried out for determining the adequate spatial filtering method through comparing and analyzing effects of parameters like defect's size and shape, intensity of light, noise of coherent source and slit number.

Optimized Design for Yard Operating System Layout of Automated Container Terminal (자동화항만의 야드 운영시스템 레이아웃 설계)

  • Hong, Dong-Hee;Chung, Tae-Choong
    • The KIPS Transactions:PartD
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    • v.10D no.1
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    • pp.101-108
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    • 2003
  • Construction of automated terminal it urgently demanded to gain the foundation of hub-port in north east Asia. Therefore we suggest an adequate operating system layout of automated terminal in Korea. In this paper the aim of automated terminal operating system is satisfied. four basic models are divided according to moving course of export and import cargo of each automated equipments, several input data are changed and analyzed dynamically by Trial and Error method, and then an optimized operating system model is selected, and designed for yard operating system layout on the basis of the selected model. Particularly, the productivity of automated port is up to the kind of automated equipments. However, because expense and present work process must be considered actually. In order to prevent confusion of the work, the method to optimize the present work and substitute prevent equipments and automated equipments was designed. It is a premise that ail the yard equipments described in this paper must be automatic except quay crane.

Poncirin Inhibits Osteoclast Differentiation and Bone Loss through Down-Regulation of NFATc1 In Vitro and In Vivo

  • Chun, Kwang-Hoon;Jin, Hyun Chul;Kang, Ki Sung;Chang, Tong-Shin;Hwang, Gwi Seo
    • Biomolecules & Therapeutics
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    • v.28 no.4
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    • pp.337-343
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    • 2020
  • Activation of osteoclast and inactivation of osteoblast result in loss of bone mass with bone resorption, leading to the pathological progression of osteoporosis. The receptor activator of NF-κB ligand (RANKL) is a member of the TNF superfamily, and is a key mediator of osteoclast differentiation. A flavanone glycoside isolated from the fruit of Poncirus trifoliata, poncirin has anti-allergic, hypocholesterolemic, anti-inflammatory and anti-platelet activities. The present study investigates the effect of poncirin on osteoclast differentiation of RANKL-stimulated RAW264.7 cells. We observed reduced formation of RANKL-stimulated TRAP-positive multinucleated cells (a morphological feature of osteoclasts) after poncirin exposure. Real-time qPCR analysis showed suppression of the RANKL-mediated induction of key osteoclastogenic molecules such as NFATc1, TRAP, c-Fos, MMP9 and cathepsin K after poncirin treatment. Poncirin also inhibited the RANKL-mediated activation of NF-κB and, notably, JNK, without changes in ERK and p38 expression in RAW264.7 cells. Furthermore, we assessed the in vivo efficacy of poncirin in the lipopolysaccharide (LPS)-induced bone erosion model. Evaluating the micro-CT of femurs revealed that bone erosion in poncirin treated mice was markedly attenuated. Our results indicate that poncirin exerts anti-osteoclastic effects in vitro and in vivo by suppressing osteoclast differentiation. We believe that poncirin is a promising candidate for inflammatory bone loss therapeutics.

Development and Field Application of the Advanced Wastewater Treatment process (KSMBR) by Hollow Fiber Submerged Membrane (침지식 중공사막을 결합한 Dynamic state 하수고도처리공정(KSMBR process)의 개발 및 현장적용평가)

  • Kim, Ji-yeon;Seo, In-seok;Kim, Hong-suck;Kim, Youn-kwon;Kim, Byung-goon;Choi, Chang-gyu;Ahn, Hyo-won;Seo, Wan-seok;Jang, Moon-seog
    • Journal of Korean Society on Water Environment
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    • v.22 no.2
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    • pp.358-363
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    • 2006
  • KSMBR process is dynamic state advanced wastewater treatment applied with Trisectional Aeration (TSA) mode combined with membrane. TSA was remodeled conventional intermittent aeration which was operated nonaeration-aeration. TSA operates nonaeration ($N_1$) - aeration (A) - nonaeration ($N_2$) in Trisectional Aeration Reactor (TAR). Organics of influent could be nearly consumed to denitrification without influence by remained DO in TAR and it could be operated about sludge return ratio of 1Q (influent base). The purpose of this study was to apply KSMBR to the full-scale plant and to evaluate efficiency of nitrogen and phosphorus removal and TSA operation. The result of this study, average CODcr/T-N and CODcr/T-P ratio were 7.8 and 59.6, respectively. BOD, TCODcr, SS, T-N, T-P, E-coli removal efficiency were 98.4, 95.2, 73.0, 69.6, 99.95 %, respectively. KSMBR obtained high removal efficiencies of C, N and P when it applied full-scale plant.