• Title/Summary/Keyword: thickness-shear

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Nonlinear FG-CNT effect on the critical buckling load of nanocomposite beams with different boundary conditions

  • Youcef Tlidji;Mohamed Zidour;Rachid Zerrouki;Abdelillah Benahmed;Boumediene Serbah;Kada Draiche;Khaled Bouakkaz
    • Advances in nano research
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    • v.17 no.4
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    • pp.323-334
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    • 2024
  • This paper deals with the effect of non-linear volume fraction distribution of carbon nanotube in the FG-CNTRC beams on the critical buckling via a hyperbolic shear deformation theory. Here, different boundary condition was considered including hinged hinged, clamped clamped and clamped-free. Single-walled carbon nanotubes are aligned and distributed in the polymer matrix in different ways to reinforce it and the material properties of (CNTRC) beams are assumed to vary gradually along the thickness direction, following a new exponential power law distribution of (CNT). The effective material properties of nanocomposite beams are estimated using the rule of mixture. The governing equations of the mathematical models are obtained by applying Hamilton's principle. The results provided of mathematical models in this work are compared and validated with similar ones in the literature. The critical buckling loads of nanocomposite beams with different boundary conditions of linear and non-linear distribution of CNT volume fraction were obtained. The effects of several parameters, including the type of beam, the volume fraction of carbon nanotubes (CNTs), the exponent degree (n), and the aspect ratio, were investigated. The distribution non-linearity of CNT volume fraction in the beam has a significant impact on the mechanical properties, particularly in buckling behavior with different boundary conditions.

Linkage Map and Quantitative Trait Loci(QTL) on Pig Chromosome 6 (돼지 염색체 6번의 연관지도 및 양적형질 유전자좌위 탐색)

  • Lee, H.Y.;Choi, B.H.;Kim, T.H.;Park, E.W.;Yoon, D.H.;Lee, H.K.;Jeon, G.J.;Cheong, I.C.;Hong, K.C.
    • Journal of Animal Science and Technology
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    • v.45 no.6
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    • pp.939-948
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    • 2003
  • The objective of this study was to identify the quantitative traits loci(QTL) for economically important traits such as growth, carcass and meat quality on pig chromosome 6. A three generation resource population was constructed from cross between Korean native boars and Landrace sows. A total of 240 F$_2$ animals were produced using intercross between 10 boars and 31 sows of F$_1$ animals. Phenotypic data including body weight at 3 weeks, backfat thickness, muscle pH, shear force and crude protein level were collected from F$_2$ animals. Animals including grandparents(F$_0$), parents(F$_1$) and offspring(F$_2$) were genotyped for 29 microsatellite markers and PCR-RFLP marker on chromosome 6. The linkage analysis was performed using CRI-MAP software version 2.4(Green et al., 1990) with FIXED option to obtain the map distances. The total length of SSC6 linkage map estimated in this study was 169.3cM. The average distance between adjacent markers was 6.05cM. For mapping of QTL, we used F$_2$ QTL Analysis Servlet of QTL express, a web-based QTL mapping tool(http://qtl.cap.ed.ac.uk). Five QTLs were detected at 5% chromosome-wide level for body weight of 3 weeks of age, shear force, meat pH at 24 hours after slaughtering, backfat thickness and crude protein level on SSC6.

Association Study between Porcine LEPR-derived Microsatellite Polymorphisms and Economic Traits (돼지 leptin receptor내 초위성체 다형성과 경제형질과의 연관성 구명)

  • Choi, B.H.;Kim, T.H.;Cho, Y.M.;Lee, H.Y.;Jeon, J.T.;Cheong, I.C.
    • Journal of Animal Science and Technology
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    • v.45 no.5
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    • pp.679-688
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    • 2003
  • The leptin receptor gene(LEPR) produces a high affinity receptor that mediates the regulation of the leptin gene. Leptin secreted from adipose tissue plays an important role in regulating feed intake and energy balance. In this study, a microsatellite marker within LEPR was selected and genotyped for the F2 population composed of 354 individuals from an intercross between Korean Native boars and Landrace sows. Totally, six alleles (255, 259, 261, 263, 265 and 267bp) and nineteen genotypes were detected in the population, of which the CE (261/265), CC (261/261) and EE (265/265) types were observed by 20.0%, 10.1% and 9.6%, respectively. Relationships between their genotypes and economic traits were analyzed. We found specific genotypes associated with economic traits such as body weight at 12 weeks of age/body fat including abdominal and trimmed fat/shear force (P〈0.001), body weight of 30 weeks of age (P〈0.01) and body weight of 3 weeks of age/back fat thickness (P〈0.05). The DD (263/263) and DF (263/267) types were associated with body weight at 3, 5, 12 and 30 weeks of age. The DF (263/267) type showed a highly significant effect on back fat thickness and body fat including abdominal and trimmed fat. The DF (263/267) type showed positive effect on shear force, whereas the BB (259/259) and DD (263/263) types negatively affected on tenderness.

A Study on Physical Properties About Velvet Antler of the Elk(Cerus canadensis) (엘크 녹용의 물성 특성에 관한 연구)

  • Sung, S.H.;Han, J.H.;Kim, Y.M.;Kim, B.K.
    • Journal of Animal Environmental Science
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    • v.13 no.3
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    • pp.201-210
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    • 2007
  • In this study, physical properties of Elk antler was investigated to develop the optimum drying and packaging methods for improving the antler quality as well as deal with diversify of demand. After the antler was sliced with 5 mm thickness, and the compressive, shear, and tensile stresses were measured at the center and velvet parts of pre-dried and dried antlers after the contained water rate of the dried antlers was maintained below 10%. The results are as follows. 1. Considering the center of pre-dried antlers, the compressive stresses were $60.73\;g/mm^2$, $145.65\;g/mm^2$, and $260.97\;g/mm^2$, respectively at the upper, middle, and lower parts while $70.67\;g/mm^2$, $811.90\;g/mm^2$, $3,235.52\;g/mm^2$, respectively for velvet layer. Considering the center of dried antlers, the compressive stresses were $190.43\;g/mm^2$, $445.81\;g/mm^2$, and $705.86\;g/mm^2$, respectively at the upper, middle, and lower parts while $734.01\;g/mm^2$, $1,238.40\;g/mm^2$, $4,134.03\;g/mm^2$, respectively for velvet layer. 2. For the pre-dried, the shear stresses were $50.24\;g/mm^2$, $294.44\;g/mm^2$, and $423.47\;g/mm^2$, respectively, and $124.14\;g/mm^2$, $367.69\;g/mm^2$, and $425.86\;g/mm^2$, respectively for the dried antlers. 3. The tensile stresses were $13.59\;g/mm^2$, $62.85\;g/mm^2$, and $112.07\;g/mm^2$, respectively for the pre-dried and $77.24\;g/mm^2$, $175.87\;g/mm^2$, and $184.06\;g/mm^2$, respectively for the dried antlers. 4. In the case of drying antlers, the physical characteristics of the antlers was. changed such as moisture evaporation, contraction, and surface hardening. For the center part, the changes of the physical characteristics were more significant at the lower part while at the upper part for the velvet layer. 5. The stress changes of Elk antlers was shown very remarkably according to growth point. Moreover, the stress was clearly higher at velvet layer part to the center part, base parts compared to the upper parts.

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Framed Steel Plate Wall subject to Cyclic Lateral Load (주기하중을 받는 골조강판벽의 실험연구)

  • Park, Hong Gun;Kwack, Jae Hyuk;Jeon, Sang Woo;Kim, Won Ki
    • Journal of Korean Society of Steel Construction
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    • v.16 no.6 s.73
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    • pp.781-792
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    • 2004
  • Experiments were performed to study the cyclic behavior of framed steel walls with thin web plates. Five specimens of single-bay and three-story steel plate walls were tested for cyclic lateral load. The parameters for the test specimens included the plate thickness and the column strength. Based on the test results, the strength, deformability, and energy dissipation capacity of the framed steel walls were studied. The test results showed that the behavioral characteristics of the framed steel walls with thin web plates were different in many aspects from those of the conventional braced frame, and the steel wall with a stiffened web plate exhibited cantilever action, high strength, and low ductility. With the framed steel plate walls, local plate buckling and tension-field action developed in the thin web plates, and plastic deformation was uniformly distributed along the wall's height. As a result, the framed steel plate walls exhibited combined flexural and shear deformation, but they also showed high strength and energy dissipation capacity. Moreover, such walls have high deformability, which was equivalent to that of the conventional moment frame. Frame members such as columns and beams, however, must be designed to resist the tension-field action of the thin web plates. If the column does not have sufficient strength, and if its sections are not compact enough, the overall strength of the framed steel wall might be significantly decreased by the development of the soft-story mechanism. The framed steel walls with thin web plates have advantages, such as high deformability and high strength. Therefore, they can be used as ductile elements in earthquake-resistant systems.

The Change in Geotechnical Properties of Clay Liner and the Contamination Behavior of Groundwater Due to Contaminant (오염물질에 의한 점토 차수재의 역학적 특성변화 및 지하수 오염거동)

  • Ha, Kwang-Hyun;Lee, Sang-Eun;Chung, Sung-Rae;Chun, Byung-Sik
    • Journal of Soil and Groundwater Environment
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    • v.13 no.1
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    • pp.13-23
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    • 2008
  • The triaxial compression tests and consolidation tests using NaCl solution and leachates as substitute pore (or saturated) water in samples were carried out to find out the behavior characteristics of strength, deformation and permeability coefficient of contaminated clay. Also, the chemical property analysis on the clay samples using scanning electron microscope and energy dispersive x-ray spectrometer were involved. The magnitudes of composition ratio were shown in the order of O, C, Si, Al, and Fe as a result of chemical composition analysis for clay samples. Besides, as the results of triaxial compression tests and consolidation tests, the shear strength, compression and permeability properties were increased with increasing in the concentration of contaminant (NaCl). It may be considered that these circumstances be caused by the changes of soil structure to flocculent structure due to the decrease in the thickness of diffuse double layer with increasing in the concentration of electrolyte. MT3D model was also using to grasp the procedures that the groundwater may be contaminated by the leachates permeated through the clay liner. The results of contaminant transport analysis showed a tendency that the predicted concentration of groundwater was higher with increasing in the initial concentration of $Cl^-$ ion and increased as a nonlinear curves with time. The transportation distance calculated by the use of regression equation between the distance from contaminant source and the concentration of $Cl^-$ ion was increased with increasing the initial concentration.

Investigation of Stiffness Characteristics of Subgrade Soils under Tracks Based on Stress and Strain Levels (응력 및 변형률 수준을 고려한 궤도 흙노반의 변형계수 특성 분석)

  • Lim, Yujin;Kim, DaeSung;Cho, Hojin;Sagong, Myoung
    • Journal of the Korean Society for Railway
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    • v.16 no.5
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    • pp.386-393
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    • 2013
  • In this study, the so-called repeated plate load bearing test (RPBT) used to get $E_{v2}$ values in order to check the degree of compaction of subgrade, and to get design parameters for determining the thickness of the trackbed foundation, is investigated. The test procedure of the RPBT method is scrutinized in detail. $E_{v2}$ values obtained from the field were verified in order to check the reliability of the test data. The $E_{v2}$ values obtained from high-speed rail construction sites were compared to converted modulus values obtained from resonant column (RC) test results. For these tests, medium-size samples composed of the same soils from the field were used after analyzing stress and strain levels existing in the soil below the repeated loading plates. Finite element analyses, using the PLAXIS and ABAQUS programs, were performed in order to investigate the impact of the strain influence coefficient. This was done by getting newly computed $I_z$ to get the precise strain level predicted on the subgrade surface in the full track structure; under wheel loading. It was verified that it is necessary to use precise loading steps to construct nonlinear load-settlement curves from RPBT in order to get correct $E_{v2}$ values at the proper strain levels.

Genetic Parameters of Reproductive and Meat Quality Traits in Korean Berkshire Pigs

  • Lee, Joon-Ho;Song, Ki-Duk;Lee, Hak-Kyo;Cho, Kwang-Hyun;Park, Hwa-Chun;Park, Kyung-Do
    • Asian-Australasian Journal of Animal Sciences
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    • v.28 no.10
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    • pp.1388-1393
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    • 2015
  • Genetic parameters of Berkshire pigs for reproduction, carcass and meat quality traits were estimated using the records from a breeding farm in Korea. For reproduction traits, 2,457 records of the total number of piglets born (TNB) and the number of piglets born alive (NBA) from 781 sows and 53 sires were used. For two carcass traits which are carcass weight (CW) and backfat thickness (BF) and for 10 meat quality traits which are pH value after 45 minutes (pH45m), pH value after 24 hours (pH24h), lightness in meat color (LMC), redness in meat color (RMC), yellowness in meat color (YMC), moisture holding capacity (MHC), drip loss (DL), cooking loss (CL), fat content (FC), and shear force value (SH), 1,942 pig records were used to estimate genetic parameters. The genetic parameters for each trait were estimated using VCE program with animal model. Heritability estimates for reproduction traits TNB and NBA were 0.07 and 0.06, respectively, for carcass traits CW and BF were 0.37 and 0.57, respectively and for meat traits pH45m, pH24h, LMC, RMC, YMC, MHC, DL, CL, FC, and SH were 0.48, 0.15, 0.19, 0.36, 0.28, 0.21, 0.33, 0.45, 0.43, and 0.39, respectively. The estimate for genetic correlation coefficient between CW and BF was 0.27. The Genetic correlation between pH24h and meat color traits were in the range of -0.51 to -0.33 and between pH24h and DL and SH were -0.41 and -0.32, respectively. The estimates for genetic correlation coefficients between reproductive and meat quality traits were very low or zero. However, the estimates for genetic correlation coefficients between reproductive traits and drip and cooking loss were in the range of 0.12 to 0.17 and -0.14 to -0.12, respectively. As the estimated heritability of meat quality traits showed medium to high heritability, these traits may be applicable for the genetic improvement by continuous measurement. However, since some of the meat quality traits showed negative genetic correlations with carcass traits, an appropriate breeding scheme is required that carefully considers the complexity of genetic parameters and applicability of data.

Analysis Models of Concrete Slabs-on-Grade Considering Horizontal Resistance at Slab Bottom and Behavior under Thermal Loads (슬래브 하부 수평저항을 고려한 지반위의 콘크리트 슬래브 해석 모델 및 온도하중에 의한 거동 분석)

  • Kim Seong-Min;An Zu-Og
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.19 no.3 s.73
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    • pp.271-282
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    • 2006
  • The behavior of the concrete slabs on grade considering the horizontal resistance at the slab bottom, which exists due to the shear resistance of the foundation and the friction between the slab and the foundation, has been investigated when the slabs-on-grade are subjected to the thermal load. Analytical formulations have been developed to include the effect of the horizontal resistance at the slab bottom employing the thin plate on an elastic foundation that is widely used for the analysis of concrete slabs-on-grade and rigid pavement systems. Finite element formulations have then been developed using the plate bending elements and the flat shell elements. The solutions from the analytical and numerical models have been compared and showed very good agreement. The sensitivity of the horizontal resistance to the stresses of the concrete slab has been investigated with various values of the slab thickness, elastic modulus, and vortical stiffness of the foundation when subjected to the temperature gradient between the top and bottom of the slab and the uniform temperature drop throughout the slab depth. The analysis results show that the horizontal resistance at the plate bottom can significantly affect the stresses of the slab when the thermal loads are applied.

Microwave hybrid sintering of NTC themistor (마이크로파 하이브리드 소결법에 의한 NTC 서미스터의 제조)

  • 최영락;안진용;안주삼;백동규;최승철
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.8 no.3
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    • pp.508-512
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    • 1998
  • The NTC thermistors were sintered by using microwave hybrid heating method at $1100^{\circ}C$~$1300^{\circ}C$ and those electrical properties were investigated. The obtained $B_{25^{\circ}C/85^{\circ}C}$ values from temperature dependence of electrical resisitivity were around 3100~3200 K which were almost the same values as conventionally sintered ones. Compared with conventional sintering process, this process could complete whole sintering process within 20 minutes. This the processing time and energy consumption could be reduced through this rapid heating by using microwave hybrid heating.t there were showed only two peaks, glycolide melting peak and lower molecular weight melting peak without lauryl alcohol. Conversion increased slowly with the reaction time up to 50 minutes, and then gave a sudden increase above that. The reaction time to disappear in glycolide melting peak during polymerization was shortened with the increase of lauryl alcohol content. Zero-shear viscosity of polyglycolic acid decreased with the increase of free acid content in glycolide.ssional energy and bending hysteresis increased. \circled3 Surface characteristics such as friction coefficient and thickness variation of highly shrinkage fabrics became relatively roughened state. \circled4 Since stiffened and roughened characteristics of highly shrinkage fabrics, drapabilities of them were significantly lowered. Additionally thermal insulation property of high shrinkage fabric was higher than that of low shrinkage fabric due to bulky and thickened feature. From the results, it is considered that the silk fabrics with high filling shrinkage have the good bulkiness and heat keeping properties and thus they have the suitable characteristics for high quality men's and women's formal garments.

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