• Title/Summary/Keyword: Volume of interest

Search Result 479, Processing Time 0.031 seconds

Shielded High-Order Gradient Coil Design for Magnetic Resonance Spectroscopy and Imaging (자기공명분석과 영상촬영을 위한 차폐된 고차경사자계코일의 설계)

  • Oh, Chang-Hyun;Hilal, Sadek K.;Yi, Yun;Kim, Min-Gi
    • Proceedings of the KOSOMBE Conference
    • /
    • v.1993 no.05
    • /
    • pp.45-48
    • /
    • 1993
  • High-order field gradients are useful for spatial localization of a volume of interest and dynamic range improvement of signal detection in NMR (Nuclear Magnetic Resonance) spectroscopy and imaging. This paper proposes a design method of shielded high-order gradient coils to reduce tile effect of eddy current on tile spectroscopy and imaging results. According to the experimental results, the shielded gradient coils produce less than 2 % eddy current compared to non-shielded coils. Two shielded $z^2$ gradient coils have been designed and constructed for 1.5 T whole-body and 3.0 T animal NMR imaging systems. Experimental results are in good agreement with the theoretically expected behavior and show the utility of the shielded high-order gradient coils.

  • PDF

Inventory Management Practices Approach to Reverse Logistics

  • Wang, Dja-Shin;Koo, Tong-Yuan
    • Industrial Engineering and Management Systems
    • /
    • v.9 no.4
    • /
    • pp.303-311
    • /
    • 2010
  • In the last few years growing interest has been dedicated to supply chain management. Modeling complexity is added to supply chain coordination problem by accounting for reverse logistics activities. The objective of this paper is to extend inventory model of manufacturing factory with respect to the production of raw material of forward logistics and recycling material of reverse logistics. The proposed model is applied to a plastic recycling process plant located in Taiwan. The case study improvement scheme shows when the recycling rate of recycling material increases from 15% to 50%, the total inventory cost of manufacturing factory decreases by 12.82%, safety stock volume decreases by 41.19% and the reorder quantity is down by 50.96%. This paper finds whether the results of the model can reach the economic profit through quantitative analysis and encourages companies integrate reverse logistics into the supply chain system.

A Study of the Relationship Between the IS Characteristics and the Distribution of IS (정보시스템의 특성과 분산형태와의 관계에 관한 연구)

  • Kim, Seong-Geun;Heo, Ju-Byeong
    • Asia pacific journal of information systems
    • /
    • v.1 no.1
    • /
    • pp.5-16
    • /
    • 1991
  • Business firms have been expressing a strong interest in an effective structure of computing resources. In this respect previous studies provide some guidelines about the deployment of hardware, but the question of which information systems (IS) would be run under the dispersed hardware is still unanswered. The main purpose of the study is to analyze the relationship between various IS characteristics and the distribution of IS. The IS characteristics studied in this research include the usage frequency of IS in a dispersed plant, the currency of information required by the headquarter, the data volume processed in the plant, the relatedness of IS with other information systems in the plant. The survey was performed over the domestic, large manufacturing firms. The most noticeable finding is that the more the updated information is required in the headquarter, or the more related IS is to other information systems in the plant, the more IS is distributed.

  • PDF

Methods of Separating Used Plastics for Recycling (폐플라스틱의 선별기술)

  • 윤여환
    • Resources Recycling
    • /
    • v.6 no.2
    • /
    • pp.12-21
    • /
    • 1997
  • Plastics waste constitutes approximately 23% by volume of the municipal solid waste(MSW) generated in the U.S. each year, and have slow rate of degradation in the environment. Therefore, there is a great deal of public pressure to recycle plastics, and more than 100 million people participate in the curbside recycling programs. Despite the high level of public interest, only 3.5% of the plastic are recycled, which is substantially lower than the recycle rates of other materials such as paper fibers, glass, and iron. Although a large part of the reason is due to the low price of virgin polymers, which in turn is due to the low price of oil, it is possible to make the plastics recycling as a profitable business by developing advanced technologies. In this communication, various methods of separating pplastics from metals and from each other are discussed.

  • PDF

CFD Analysis on the Continuous and Variable Damping Characteristics of a Semi-Active Shock Absorber (반능동형 충격흡수기의 연속가변 감쇠특성에 대한 CFD 해석)

  • 윤준원
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.12 no.2
    • /
    • pp.101-108
    • /
    • 2004
  • Recently, a semi-active shock absorber has been taking interest because of its low cost and simple structure than the active one. CFD analysis has been conducted to investigate the continuous and variable damping characteristics of the semi-active shock absorber. Also, the flow resistance characteristics of a spool valve has been examined to identify individual parameters(namely, exponent and discharge coefficient) of pressure-flow rate relation needed for the accurate valve modeling. The flow field in the damping valve was simulated using the commercial code, CFX-5.3. The numerical results showed reasonable agreement with the experimental outputs. The pressure distribution with the variation of spool opening length and volume flow rate were discussed in detail. And the continuous and variable damping performance was found clearly. The individual parameters of spool valve were obtained as a function of orifice area. The exponent and discharge coefficient were fitted in with the first and the third polynomial respectively.

A Study on the Computerized Formulation of the Thermodynamic Properties of Water and Steam by Personal Computer (P.C.를 이용한 물과 증기 열물성치의 전산수식화에 관한 연구)

  • 김경석;김원영;김경근;김용모
    • Journal of Advanced Marine Engineering and Technology
    • /
    • v.16 no.4
    • /
    • pp.88-101
    • /
    • 1992
  • Properties of water and steam are very important for the steam ejector CAD program as a subroutine and design of the Shell & Tube type steam condenser. Present formular programs are based on the Skeleton Table of ASME, and are able to calculate the thermodynamoc properties of water and steam throughout the whole of the region that extend in pressure from 0 to 1000 bar and temperature from 0.01 to 80$0^{\circ}C$. When comparing calculated values for specific volume, enthalpy and entropy with the Skeleton Table 1967 and IAPS Skeleton Table 1984, values fell well within tolerances specified except near the extremes of the range of interest at the critical point and triple point, where deviations were slightly larger.

  • PDF

Treatment of an Atrophic Scar with Fractional Carbon Dioxide Laser-assisted Poly-L-lactic Acid Delivery

  • Kim, Wan Jin;Jung, Ha Rin;Lee, Sang Ju;Cho, Han Kyoung
    • Medical Lasers
    • /
    • v.10 no.3
    • /
    • pp.181-184
    • /
    • 2021
  • Scars can cause great psychological stress among patients. Currently, there are numerous topical agents, laser and surgical treatments available for skin rejuvenation and scar minimization. Laser-assisted drug delivery (LADD) is a treatment method that increases drug delivery by stimulating the skin physically and chemically to enhance the penetration of topical agents. This is one of the areas of great interest in the treatment of various skin diseases in addition to its use for cosmetic purposes. In particular, LADD is relatively non-invasive and has advantages in terms of accessibility and stability. Poly-L-lactic acid (PLLA) is a collagen stimulator known to gradually restore skin volume by inducing inflammation and fibroplasia. Herein, we report a case of treatment of an atrophic scar with fractional carbon dioxide laser-assisted PLLA delivery.

Laundering Factors in Soil Removal

  • Kadolph, Sara J.;Schofield-Tomschin, Sherryl A.;Kwon, Young-Ah
    • Fashion & Textile Research Journal
    • /
    • v.3 no.5
    • /
    • pp.455-465
    • /
    • 2001
  • Assessing soil removal is of interest to the washing machine industry because of government-mandated energy savings and changes in detergent formulation and consumer laundry practices. We designed this study to examine the laundry process from a holistic perspective by integrating factors perceived to be of importance. Our purpose was to assess the impact of selected variables (fabric and soil type, wash temperature and time. detergent amount, and degree of agitation) on soil removal using accelerated laundry conditions. We used the Taguchi method to develop the research design and ANOVA to analyze the data. Although soil removal was affected by fabric type, soil type, type and amount of detergent, degree of agitation, wash time and temperature, and water hardness and volume, wash temperature was the most significant variable.

  • PDF

Nanotechnology in elastomers- Myth or reality

  • Shanmugharaj, A.M.;Ryu, Sung-Hun
    • Rubber Technology
    • /
    • v.12 no.1
    • /
    • pp.1-7
    • /
    • 2011
  • Nanotechnology is the fast becoming key technology of the $21^{st}$ century. Due to its fascinating size-dependent properties, it has gained significant important in various sectors. Myths are being formed on the proverbal nanotechnology market, but the reality is the nanotechnology is not a market but a value chain. The chain comprises of - nanomaterials (nanoparticles) and nanointermediates (coatings, compounds, smart fabrics). Elastomer based nanocomposites reinforced with low volume fraction of nanofillers is the first generation nanotechnology products and it has attracted great interest due to their fascinating properties. The incorporation of nanofillers such as nanolayered silicates, carbon nanotubes, nanofibers, metal oxides or silica nanoparticles into elastomers improves significantly their mechanical, thermal, barrier properties, flame retardency etc., Extremely small particle size, high aspect ratio and large interface area yield an excellent improvement of the properties in a wide variety of the materials. Uniform dispersion of the nanofillers is a general prerequisite for achieving desired properties. In this paper, current developments in the area of elastomer based nanocomposites reinforced with layered silicate and carbon nanotube fillers are highlighted.

  • PDF

Characterization of Cordierite by SEM, Microanalysis X and TEM (SEM, X선 마이크로 분석기, TEM에 의한 코디에라이트의 특성 연구)

  • Han, Byoung-Sung
    • Journal of the Korean Institute of Telematics and Electronics
    • /
    • v.27 no.8
    • /
    • pp.1250-1254
    • /
    • 1990
  • The cordierite (MgO, SiO2, Al2O3) is of great interest for microelectronic packaging of integrated circuits. Its main advantages are low dielectric constant and low thermal expansion. The cordierite precursor is obtained by sol-gel synthesis using organic and inorganic compounds. The obtained cordierite precursor is an amorphous state at about 900\ulcorner. Green and fired cordierite samples were studied by SEM. Microanalysis X and TEM for microscopic properties. The fired cordierite shows forte diminution of Mg in comparison with its value at volume and the deficit of Mg compensates by sugmentation of Al and Si \ulcornercordierite and \ulcornercordierite are present near the surface (< 100) and small quantities of magnesium aluminate (MgAl2O4)is presented spinnel phase.

  • PDF