• Title/Summary/Keyword: pre-compression

Search Result 290, Processing Time 0.021 seconds

Low-Stress Physical/Mechanical Properties of Cochineal-dyed Cotton, Silk, Nylon, and Polyester Fabrics subjected to Chitosan-Pretreatment

  • Kim, Jong-Jun;Jeon, Dong-Won;Kim, Sun-Hwa
    • Journal of Fashion Business
    • /
    • v.7 no.6
    • /
    • pp.50-56
    • /
    • 2003
  • Chitosan has been widely applied to the products in various industries such as textile fabrics, apparels, foods, medical area, etc. Cochineal has long been employed as one of natural dyestuffs in the textile industry. The effect of chitosan pre-treatment on the low-stress physical and mechanical properties of cochineal-dyed fabrics including cotton, silk, nylon and polyester fabrics was investigated in this study. The chitosan treatment and mordanting of the fabrics changed the bending, shear, compression, and surface properties of the fabrics. In cotton fabric specimens, while the increase of B(bending rigidity) of cotton is relatively high, the increase of G(shear rigidity) of cotton is relatively low. In nylon and PET fabric specimens, while the increase tendency of B is relatively low, that of G is high compared to the corresponding cotton fabrics.

An Experimental Study on Four-season Dedicated Outdoor Air Handling Unit (사계절 외기 전용 공조기에 대한 실험적 연구)

  • Park, Seung-Tae;Kim, Jong-Cheon;Hong, Young-Ju;Kim, Youn-Gil
    • Proceedings of the SAREK Conference
    • /
    • 2008.06a
    • /
    • pp.577-582
    • /
    • 2008
  • The present study has been conducted to study the performance of Dedicated outdoor air handling unit. Dedicated outdoor air handling unit consists of pre-cooler, dehumidification and after cooler. By combining dedicated outdoor air-conditioning and heat pump, a new four-season dedicated outdoor air handling unit has been developed. Amount of energy saved and condition when this new system is superior to conventional vapor-compression cooling system has been presented.

  • PDF

Tools for forensic analysis of concrete structures

  • Vecchios, Frank J.;Bentz, Evan C.;Collins, Michael P.
    • Computers and Concrete
    • /
    • v.1 no.1
    • /
    • pp.1-14
    • /
    • 2004
  • Computer-based analysis tools for forensic assessment of reinforced concrete structures are presented. The analysis tools, mostly in the form of nonlinear finite element procedures, are based on the concepts and formulations of the Modified Compression Field Theory. Relevant details regarding their formulation are provided. Development of realistic constitutive models and corroboration of the analysis procedures, through comprehensive experimental programs, are discussed. Also presented are graphics-based pre- and post-processors, which are of significant aid in structural modeling, input of data, and interpretation of analysis results. The details and results of a case study, illustrating the application and value of such analytical tools, are also discussed.

End-Gas Temperature Measurments in a DOHC Spark-Ignition Engine Using CARS (CARS를 이용한 DOHC 스파크 점화 기관의 말단 가스 온도 측정)

  • 최인용;전광민;박철웅;한재원
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.7 no.7
    • /
    • pp.122-128
    • /
    • 1999
  • CARS(Coherent anti-Stokes Raman Spectroscopy) temperature measurement under engine-like condition was validated by measuring unburned gas temperatures of premixed propane-air flame in a constant volume combustion chamber. The measured temperatures were compared with predictions of 2 zone flame propagation model. End-gas temperatures were measured were measured by CARS technique in a conventional 4 cylinder DOHC spark-ignition engine fueled with PRF 80. Cylinder pressure was measured simultaneously with CARS signal and used as a parameter on fitting CARS spectrum to library of theoretical spectra. There was a good agreement between the measured temperature and adiabatic core temperature calculated from measured cylinder pressure. Significant heating by pre-flame reaction in the gas was observed in the late part of compression stroke.

  • PDF

Numerical investigation of mechanical properties of nanowires: a review

  • Gu, Y.T.;Zhan, H.F.;Xu, Xu
    • Interaction and multiscale mechanics
    • /
    • v.5 no.2
    • /
    • pp.115-129
    • /
    • 2012
  • Nanowires (NWs) have attracted intensive researches owing to the broad applications that arise from their remarkable properties. Over the last decade, immense numerical studies have been conducted for the numerical investigation of mechanical properties of NWs. Among these numerical simulations, the molecular dynamics (MD) plays a key role. Herein we present a brief review on the current state of the MD investigation of nanowires. Emphasis will be placed on the FCC metal NWs, especially the Cu NWs. MD investigations of perfect NWs' mechanical properties under different deformation conditions including tension, compression, torsion and bending are firstly revisited. Following in succession, the studies for defected NWs including the defects of twin boundaries (TBs) and pre-existing defects are discussed. The different deformation mechanism incurred by the presentation of defects is explored and discussed. This review reveals that the numerical simulation is an important tool to investigate the properties of NWs. However, the substantial gaps between the experimental measurements and MD results suggest the urgent need of multi-scale simulation technique.

Effective and Safe Application of Radiofrequency Ablation for Benign Thyroid Nodules (양성갑상선결절에 대한 효과적이고 안전한 고주파절제의 적용)

  • Jin Yong Sung
    • Journal of the Korean Society of Radiology
    • /
    • v.84 no.5
    • /
    • pp.985-998
    • /
    • 2023
  • Radiofrequency ablation (RFA) has been a representative, non-surgical treatment for benign thyroid nodules that cause cosmetic problems or compression symptoms. The procedure of RFA should be performed effectively and safely. This review discusses the patient selection, pre-procedure evaluation and planning, principles, devices, techniques, and complications with reference to the guidelines and research on thyroid RFA. In particular, this review will devote to introduce RFA techniques and to provide practical help in the implementation of this procedure.

Local Buckling in Steel Box Girder Bridge with Lifting and Lowering Support Method (지점 상승 하강 공법에 의한 강상자형교의 국부좌굴)

  • Koo, Min Se;Jeong, Jae Woon;Na, Gwi Tae
    • Journal of Korean Society of Steel Construction
    • /
    • v.15 no.1
    • /
    • pp.77-85
    • /
    • 2003
  • The lifting and lowering supports method makes up for the weak points in the classical method and provides makes construction economical effect to construction. The application of pre-compression to continuous steel box girder bridges makes it possible to reduce the amount of steel, the height of girders and consequently, the cost consequentlyof the bridges' construction by through the process of concrete filling- up and the lifting-lowering of the inner supports. The lifting and lowering supports method is apt to cause local buckling in the lower flange and web plates by due to the process of the lifting of the inner supports. Therefore iln this study, therefore, the possibility of local buckling could be decreased, in consideration of the lifting force and the buckling strength of stiffened plates, by increasing the number of longitudinal stiffeners and the installation of extended longitudinal stiffeners on the lower flange and the web plates in the range of positive moment.

Analytical Study on Buoyancy Preflexion Effects on Structural Performance of Concrete Floating Structure (부력 프리플랙션 효과가 콘크리트 부유구조체의 구조성능에 미치는 영향에 대한 해석적 연구)

  • Lee, Du-Ho;Jeong, Youn-Ju
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.32 no.2A
    • /
    • pp.75-83
    • /
    • 2012
  • In this study, an analytical studies were carried out for the buoyancy preflexion method to improve structural performance of concrete floating structures. The buoyancy preflexion means that the preflexion effects were induced to the floating structure due to the difference in buoyancy between the pontoon modules composing the floating structures. In order to verify the buoyancy preflexion effects, an analytical studies were carried out for the floating structures. The size and dimensions of FE model were determined through the structural design process. The parameter of this analytical study was length ratios of central module part, which induces buoyancy preflexion effects, to the total length. The analysis results were pre-compression on the bottom concrete slab and displacement of freeboard due to buoyancy preflexion effects. These results were processed according to the loading step, buoyancy preflexion loads on the bottom and live loads on the topside. Then, the buoyancy preflexion effects on structural performance was analyzed. As the results of this study, it was found that the buoyancy preflexion significantly influence on structural performance of floating structures. According to the length ratio, the buoyancy preflexion effects have a tendency of parabolic form and maximized at the length ratio of 40~60%. The buoyancy preflexion method is simple in principle and easy in application. Also, it can effectively induce pre-compression on the bottom concrete slab. Therefore, it can be concluded that the buoyancy preflexion method contribute to the improvement of structural performance and decreasing of the cross-sectional depth of floating structures.

Effect of $N_2+H_2$ Forming Gas Annealing on the Interfacial Bonding Strength of Cu-Cu thermo-compression Bonded Interfaces (Cu-Cu 열압착 웨이퍼 접합부의 계면접합강도에 미치는 $N_2+H_2$ 분위기 열처리의 영향)

  • Jang, Eun-Jung;Kim, Jae-Won;Kim, Bioh;Matthias, Thorsten;Hyun, Seung-Min;Lee, Hak-Joo;Park, Young-Bae
    • Journal of the Microelectronics and Packaging Society
    • /
    • v.16 no.3
    • /
    • pp.31-37
    • /
    • 2009
  • Cu-Cu thermo-compression bonding process was successfully developed as functions of the $N_2+H_2$ forming gas annealing conditions before and after bonding step in order to find the low temperature bonding conditions of 3-D integrated technology where the quantitative interfacial adhesion energy was measured by 4-point bending test. While the pre-annealing with $N_2+H_2$ gas below $200^{\circ}C$ is not effective to improve the interfacial adhesion energy at bonding temperature of $300^{\circ}C$, the interfacial adhesion energy increased over 3 times due to post-annealing over $250^{\circ}C$ after bonding at $300^{\circ}C$, which is ascribed to the effective removal of native surface oxide after post-annealing treatment.

  • PDF

Chest Compression Energy(kg) Measurement of 4 Types of Rescue Device on the Floor (4종류의 구급장비 및 마루(Floor) 위에서 시행한 가슴압박 에너지(kg)측정 실험에 관한 연구)

  • Shin, Dong-Min;Han, Yong-Taek;Kim, Seung-Yong;Park, Si-Eun
    • Journal of the Korean Society of Safety
    • /
    • v.29 no.6
    • /
    • pp.125-131
    • /
    • 2014
  • The purpose of this study is to investigate the effect of high quality CPR using the 4 types of rescue device equipment and chest compressions energy measurement in pre-hospital settings. So, we used the mode to insert load cell in ALS Skill master Manikin to develop CFMM(Compression Force Measurement Manikin) on main stretcher, CPR board, long spine board, scoop stretcher and floor. And, our research team could know that the main stretcher needed average force of 32.55 (${\pm}1.01$) kg, CPR board of 27.23 (${\pm}1.08$) kg, long spine board of 27.13 (${\pm}1.18$) kg, Scoop Stretcher of 27.38 (${\pm}1.05$) kg and Floor of 27.24 (${\pm}0.93$) kg. CPR board must be necessary in the case of CPR on main stretcher in a moving ambulance. But if the condition of patient's back surface is the removable stretcher and the long spine plate, the patient doesn't have to be spent time to use a CPR board. Furthermore, this research suggests to consider that how to take advantage of the education to students for the equipment to check in real time the energy(kg) requirement of chest compressions.