• Title, Summary, Keyword: sizing

Search Result 1,198, Processing Time 0.038 seconds

Wavelet Analysis of Ultrasonic Echo Waveform and Application to Nondestructive Evaluation (초음파 에코파형의 웨이브렛 변환과 비파괴평가에의 응용)

  • Park, Ik-Keun;Park, Un-Su;Ahn, Hyung-Keun;Kwun, Sook-In;Byeon, Jai-Won
    • Journal of the Korean Society for Nondestructive Testing
    • /
    • v.20 no.6
    • /
    • pp.501-510
    • /
    • 2000
  • Recently, advanced signal analysis which is called "time-frequency analysis" has been used widely in nondestructive evaluation applications. Wavelet transform(WT) and Wigner Distribution are the most advanced techniques for processing signals with time-varying spectra. Wavelet analysis method is an attractive technique for evaluation of material characterization nondestructively. Wavelet transform is applied to the time-frequency analysis of ultrasonic echo waveform obtained by an ultrasonic pulse-echo technique. In this study, the feasibility of noise suppression of ultrasonic flaw signal and frequency-dependent ultrasonic group velocity and attenuation coefficient using wavelet analysis of ultrasonic echo waveform have been verified experimentally. The Gabor function is adopted the analyzing wavelet. The wavelet analysis shows that the variations of ultrasonic group velocity and attenuation coefficient due to the change of material characterization can be evaluated at each frequency. Furthermore, to assure the enhancement of detectability and naw sizing performance, both computer simulated results and experimental measurements using wavelet signal processing are used to demonstrate the effectiveness of the noise suppression of ultrasonic flaw signal obtained from austenitic stainless steel weld including EDM notch.

  • PDF

Aluminum Powder Metallurgy Current Status, Recent Research and Future Directions

  • Schaffer, Graham
    • Proceedings of the Korean Powder Metallurgy Institute Conference
    • /
    • /
    • pp.7-7
    • /
    • 2001
  • The increasing interest in light weight materials coupled to the need for cost -effective processing have combined to create a significant opportunity for aluminum P/M. particularly in the automotive industry in order to reduce fuel emissions and improve fuel economy at affordable prices. Additional potential markets for Al PIM parts include hand tools. Where moving parts against gravity represents a challenge; and office machinery, where reciprocating forces are important. Aluminum PIM adds light weight, high compressibility. low sintering temperatures. easy machinability and good corrosion resistance to all advantages of conventional iron bm;ed P/rv1. Current commercial alloys are pre-mixed of either the AI-Si-Mg or AL-Cu-Mg-Si type and contain 1.5% ethylene bis-stearamide as an internal lubricant. The powder is compacted in closed dies at pressure of 200-500Mpa and sintered in nitrogen at temperatures between $580~630^{\circ}C$ in continuous muffle furnace. For some applications no further processing is required. although most applications require one or more secondary operations such as sizing and finishing. These sccondary operations improve the dimension. properties or appearance of the finished part. Aluminum is often considered difficult to sinter because of the presence of a stable surface oxide film. Removal of the oxide in iron and copper based is usually achieved through the use of reducing atmospheres. such as hydrogen or dissociated ammonia. In aluminum. this occurs in the solid st,lte through the partial reduction of the aluminum by magncsium to form spinel. This exposcs the underlying metal and facilitates sintering. It has recently been shown that < 0.2% Mg is all that is required. It is noteworthy that most aluminum pre-mixes contain at least 0.5% Mg. The sintering of aluminum alloys can be further enhanced by selective microalloying. Just 100ppm pf tin chnnges the liquid phase sintering kinetics of the 2xxx alloys to produce a tensile strength of 375Mpa. an increilse of nearly 20% over the unmodified alloy. The ductility is unnffected. A similar but different effect occurs by the addition of 100 ppm of Pb to 7xxx alloys. The lend changes the wetting characteristics of the sintering liquid which serves to increase the tensile strength to 440 Mpa. a 40% increase over unmodified aIloys. Current research is predominantly aimed at the development of metal matrix composites. which have a high specific modulus. good wear resistance and a tailorable coefficient of thermal expnnsion. By controlling particle clustering and by engineering the ceramic/matrix interface in order to enhance sintering. very attractive properties can be achicved in the ns-sintered state. I\t an ils-sintered density ilpproaching 99%. these new experimental alloys hnve a modulus of 130 Gpa and an ultimate tensile strength of 212 Mpa in the T4 temper. In contest. unreinforcecl aluminum has a modulus of just 70 Gpa.

  • PDF

Classification of Body Types for sizes of Ready-to-Wear-focusing on Korean female aged from 18 to 24 (성인 여성의 기성복 치수를 위한 체형 분류)

  • 김경화;남윤자
    • Journal of the Korean Society of Costume
    • /
    • v.53 no.6
    • /
    • pp.145-159
    • /
    • 2003
  • The purpose of this study was to classify body type for ready-to-wear sizes. The subjects were 300 women ages of 18-24. they were measured direct anthropometry. The body types for sizing system were divided by Rohrer Index. KS drop value and ISO drop value. The results of this study were as follows. 1. By adapting the Rohrer Index. we classify 3 types from anthropometric measurements. The thin type covered 39.3%, the standard type 51.0% and the obesity type 18.7%. The characteristics of clusters were as follows. Thin type was characterized by tall. slender type and slim. The standard type was characterized by middle sized. The obesity type was characterized by short. fat type. and large bust. 2. By adapting the KS system drop value. we classify 3 types from anthropometric measurements. The H type(drop 0) covered 25.6%. the N type(drop 6) 65.2% and the A type(drop 12) 9.2%. Type H was slightly tall large bust. and curved from waist to hip. Type A was slightly thin. large hip and smaller bust than type N. Principal factor components were bust size. The height could be divided into three groups. The Petite(l50cm) covered 5.5%. the Regular(l60cm) 64.7% and the Tall(l70cm) 29.8%. Through the crosstab of height and body type. we extracted regular height by N type 46.2% the largest cell. The body type was the higher order of N type. H type and A type. The tall was the higher order of Regular. Tall and Petite. 3. By adapting the ISO system drop value. we classify 3 types from anthropometric measurements. The H type(drop 0) covered 15.0%. the M type(drop 6) 41.0% and the A type(drop 12) 44.0%. Type H was slightly short. slightly fat and large bust. Type A was slightly tall. slight thin than type M. The height could be divided into three groups. We adjust the height section after allow for height distribution. The Short(152cm) covered 12.8%. the Regular(160cm) 66.9% and the Long(168cm) 20.3%. Through the crosstab of height and body type, we extracted regular height by M type 29.3% the largest cell. The body type was the higher order of M type, A type and H type. The tall was the higher order of Regular, Long and short.

CAPACITY EXPANSION MODELING OF WATER SUPPLY IN A PLANNING SUPPORT SYSTEM FOR URBAN GROWTH MANAGEMENT (도시성장관리를 위한 계획지원체계에서 상수도의 시설확장 모델링)

  • Hyong-Bok, Kim
    • Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
    • /
    • /
    • pp.9-21
    • /
    • 1995
  • A planning support system enhances our ability to use water capacity expansion as an urban growth management strategy. This paper reports the development of capacity expansion modeling of water supply as part of the continuing development of such a planning support system (PEGASUS: Planning Environment for Generation and Analysis of Spatial Urban Systems) to incorporate water supply, This system is designed from the understanding that land use and development drive the demand for infrastructure and infrastructure can have a significant influence on the ways in which land is developed and used. Capacity expansion Problems of water supply can be solved in two ways: 1) optimal control theory, and 2) mixed integer nonlinear programming (MINLP). Each method has its strengths and weaknesses. In this study the MINLP approach is used because of its strength of determining expansion sizing and timing simultaneously. A dynamic network optimization model and a water-distribution network analysis model can address the dynamic interdependence between water planning and land use planning. While the water-distribution network analysis model evaluates the performance of generated networks over time, the dynamic optimization model chooses alternatives to meet expanding water needs. In addition, the user and capacity expansion modeling-to-generate-alternatives (MGA) can generate alternatives. A cost benefit analysis module using a normalization technique helps in choosing the most economical among those alternatives. GIS provide a tool for estimating the volume of demanded water and showing results of the capacity expansion model.

  • PDF

Estimation of the Kinetic Energy of Raindrops for Hourly Rainfall Considering the Rainfall Particle Distribution (강우입자분포를 고려한 시강우의 강우에너지 산정 연구)

  • Kim, Seongwon;Jeong, Anchul;Lee, Giha;Jung, Kwansue
    • Journal of the Korean Geoenvironmental Society
    • /
    • v.19 no.12
    • /
    • pp.15-23
    • /
    • 2018
  • The occurrence of soil erosions in Korea is mostly driven by flowing water which has a close relationship with rainfalls. The soil eroded by rainfalls flows into and deposits in the river and it polluted the water resources and making the rivers become difficult to be managed. Recently, the frequency of heavy rainfall events that are more than 30 mm/hr has been increasing in Korea due to the influence of climate change, which creating a favourable condition for the occurrence of soil erosion within a short time. In this study, we proposed a method to estimate the distribution of rainfall intensity and to calculate the energy produced by a single rainfall event using the cumulative distribution function that take into account of the physical characteristics of rainfall. The raindrops kinetic energy estimated by the proposed method are compared with the measured data from the previous studies and it is noticed that the raindrops kinetic energy estimated by the rainfall intensity variation is very similar to the results concluded from the previous studies. In order to develop an equation for estimating rainfall kinetic energy, rainfall particle size data measured at a rainfall intensity of 0.254~152.4 mm/hr were used. The rainfall kinetic energy estimated by applying the cumulative distribution function tended to increase in the form of a power function in the relation of rainfall intensity. Based on the equation obtained from this relationship, the rainfall kinetic energy of 1~80 mm/hr rainfall intensity was estimated to be $0.03{\sim}48.26Jm^{-2}mm^{-1}$. Based on the relationship between rainfall intensity and rainfall energy, rainfall kinetic energy equation is proposed as a power function form and it is expected that it can be used in the design of short-term operated facility such as the sizing of sedimentation basin that requires prediction of soil loss by a single rainfall event.

A study on the program development for area optimizing of damper ports in road tunnels with transverse ventilation system (횡류식 도로터널의 급, 배기구 포트 개구면적 최적화 프로그램 개발 연구)

  • Jo, Hyeong-Je;Chun, Kyu-Myung;Min, Dea-Kee;Kim, Jong-Won;Beak, Jong-Hoon
    • Journal of Korean Tunnelling and Underground Space Association
    • /
    • v.21 no.1
    • /
    • pp.177-188
    • /
    • 2019
  • The purpose of the optimization of the installation of supply/exhaust ports for tunnels with transverse ventilation system is to supply fresh air from outside to inside of tunnels uniformly and exhaust pollutant from tunnels properly for creating safe and clean environment for tunnel users. For this purpose, a ventilation port area optimization program was developed to obtain a uniform supply or exhaust air volume inside a great depth double deck tunnel with transverse ventilation system. In order to area optimize the developed port sizing program, the wind velocity was measured in the duct of the currently operated tunnel with semi-transverse ventilation. Also 3D cfd was performed on the same tunnel and cfd results were compared to the measured value. As a result, the error rate between the predicted value from the program and measured value was 6.72%, while the error rate between the predicted value from the program and 3D cfd analysis value was 4.86%. Both of comparison results show less than 10% of error rate. Thus It is expected that supply/exhaust port optimization design of transverse ventilation tunnel can be possible with using this large exhaust port area optimization program.

Transport and management of diffuse pollutants using low impact development technologies applied to highly urbanized land uses (고도화 도시지역에 적용된 LID 기법의 비점오염물질 관리 및 이동)

  • Geronimo, F.K.F.;Choi, H.S.;Kim, L.H.
    • Journal of Wetlands Research
    • /
    • v.21 no.2
    • /
    • pp.173-180
    • /
    • 2019
  • This study was conducted to understand factors affecting TSS and heavy metals transport on the road, parking lot and roof. During storm events, heavy metals, which were mostly attached to TSS, were also transported when TSS was washed off in the road, parking lot and roof. This finding may be supported by the significant correlations between TSS load and total and soluble heavy metals load including Cr, Fe, Cu, and Pb (Pearson r value: 0.52 to 0.73; probability p value<0.01). Generation and transport of TSS and heavy metals were greater in the road and parking lot compared to the roof due to vehicular activities, slope and greater catchment areas of these sites. It was found that TSS transport during peak flows of storm events ranges from 65% to 75% implying that by controlling peak flows, TSS transportation to nearby water bodies may be decreased. Depending on the target TSS and heavy metal reduction, sizing of low impact development (LID) technologies and green infrastructures (GI) such as infiltration trench, tree box filter, and rain garden may be calculated. Future researchers were recommended to assess the limitations of the systems and determine the design considerations for these types of facilities.

A Spatial Analysis on the Socio-Cultural Level of Informatization Aspects (정보화 차원의 사회 ${\cdot}$ 문화 발전 수준에 대한 공간 분석)

  • Yoo, Yeong-Jun
    • Journal of the Korean Geographical Society
    • /
    • v.31 no.3
    • /
    • pp.529-541
    • /
    • 1996
  • The Korean economy has recently changed from industry-based economy toward information-based one, empha-sizing on information utiliation and technological development. It is important to examine the background for the incoming information society and spatial aspect of infromation, because informati-zation process itself contains spatial features like spatial concentrtion and dispersion. This paper generally focuses on the socio-cultural aspects of the informati-zation aspects. The main questions are as follows: 1) what are the ain questions of the exsisting Korean case studies on the informatization; 2) how can we find the charateristics of spatial concentration of informatization by informatization indices; 3) is there any relationship between the degree of informatiztion and regional development? The results of this study can be found in the following facts: (1) The exsisting studies cannot be generallized as spatial analysis on the informatization In general, they focus only a single aspect of information industry or information job. Futhermore, their spatial unit of analysis is limited to provincial level, rather thn city-level micro study. (2) There are big differences between the Capital region, especially Seoul, and others with regard to the socio-cultural aspects of informatiation. Such informatization is concentrated in Seoul. Inchon and Kyeonggi-do, which are the better positions in information intensive activities. (3) The regional differences for the level of informatization are much bigger than those for the level of welfare, suggesting that the informatization tends to concentrate in specified large cities like Seoul. It is clear the Korea is now entering the initial stage of information society.

  • PDF

Characteristics of Building Structural System with IsoTruss® Grid (IsoTruss® 그리드를 적용한 건물구조시스템의 특성)

  • Kim, Tae-Heon;Kim, Young-Chan
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.18 no.2
    • /
    • pp.737-742
    • /
    • 2017
  • Recently, unconventional high-rise building shapes have attracted attention as a landmark of metropolitan cities and the search for innovative building forms in architecture is ongoing. In this study, $Isotruss^{(R)}$ grid(ITG) used in smaller scale structures was applied to building structural systems and its structural performance was examined. The structural behavior of an ITG was compared with that of a diagrid structure as a reference structure. The stiffness-based design method of the diagrid system was used for the preliminary design stage of member sizing in an ITG. The structural design of 16, 32, and 48-story buildings was carried out for the two systems with the same size. The angle of the inclined columns for ITG and diagrid was $59^{\circ}$ and $68.2^{\circ}$, respectively. The lateral stiffness, steel tonnage of the exterior frame, axial strength ratio, story drift ratio, and natural frequency of the two systems were compared. Based on the analysis result of 6 buildings, the two systems had similar structural capacity; 93.3% and 88.7% of the lateral load was carried by the perimeter frame in the ITG system and diagrid system, respectively. This suggests that the ITG system is better in arranging core columns. Therefore, the proposed ITG system has not only a unique façade, but also substantial structural capacity equivalent to the existing system.

A Comparative Study on Chinese Adult women's constitutional components and Somatotype Characteristic (지역별.연령별 중국 성인여성(地域別.年齡別 中國 成人女性)의 체형구성 요인(體型構成 要因)과 유형 비교 연구(類型 比較 硏究))

  • Wee, Hye-Jung;Sohn, Hee-Soon
    • Journal of Fashion Business
    • /
    • v.10 no.5
    • /
    • pp.58-73
    • /
    • 2006
  • The purpose of this study was to improve of fittness and coverage rate of exporting domestic clothing to China for Chinese Adult Female. For study, It was measured 1381 female women aged between 19 and 50 who resident in Beijing and Shanghai in China. as a sample, 1360 female women was seleted for development of apparel sizing system. As for the method of this study was made of 111 items by indirect measures done during Jun. 23 $\sim$ Aug. 7, 2004. Data analysis were processed by SPSS WIN 10.0 Program was used to for technical statistical analysis, correlation analysis, factor analysis, ANOVA(t-test and F-test), duncan's multiple test. The result was as follows: Chinese Adult women's constitutional components determined by factor analysis, six components could be identified: factor 1:constitutional obesty and width size, factor 2: longistudinal body size, factor 3: shoulder form and size, factor 4: longistudinal upper body size, factor 5: under body size, factor 6: shoulder dropping. According to the Women's Wear Specifications(GB/T 1335.2-1997) by drop, body types of Chinese Adult female was classified into six types, it was Y, A, B, C and Z, D. In order, A type as standard somatotype(49.8%), B type(26.9%), Y type (18.8%), C type(2.9%). Y type had the average height and shoulder, bust girth. They were slimmer in overall terms. A type had a normal obesity and body size in height, shoulder, bust girth. They were average Chinese Women. B type had a smaller then A type. They were more obes and thick waist girth. C type had the highest obesity, the widest shoulder and bust girth, and thick waist girth. The characteristics of each body type following the body type structure factor are Y-type for slender type, A-type for standard type, B-type for slightly large type, and C-type for obese type. For each region, the Beijing area had in the order of A-type, Y-type, B-type and C-type, and the Shanghai area had in the order of A-type, B-type, Y-type and C-type.