Thermomechanical deformation in porous generalized thermoelastic body with variable material properties

Kumar, Rajneesh,Devi, Savita Techno-Press 2010 Structural Engineering and Mechanics, An Int'l Jou Vol.34 No.3

The two-dimensional deformation of a homogeneous, isotropic thermoelastic half-space with voids with variable modulus of elasticity and thermal conductivity subjected to thermomechanical boundary conditions has been investigated. The formulation is applied to the coupled theory(CT) as well as generalized theories: Lord and Shulman theory with one relaxation time(LS), Green and Lindsay theory with two relaxation times(GL) Chandrasekharaiah and Tzou theory with dual phase lag(C-T) of thermoelasticity. The Laplace and Fourier transforms techniques are used to solve the problem. As an application, concentrated/uniformly distributed mechanical or thermal sources have been considered to illustrate the utility of the approach. The integral transforms have been inverted by using a numerical inversion technique to obtain the components of displacement, stress, changes in volume fraction field and temperature distribution in the physical domain. The effect of dependence of modulus of elasticity on the components of stress, changes in volume fraction field and temperature distribution are illustrated graphically for a specific model. Different special cases are also deduced.

Thermomechanical deformation in porous generalized thermoelastic body with variable material properties

Rajneesh Kumar,Savita Devi 국제구조공학회 2010 Structural Engineering and Mechanics, An Int'l Jou Vol.34 No.3

The two-dimensional deformation of a homogeneous, isotropic thermoelastic half-space with voids with variable modulus of elasticity and thermal conductivity subjected to thermomechanical boundary conditions has been investigated. The formulation is applied to the coupled theory(CT) as well as generalized theories: Lord and Shulman theory with one relaxation time(LS), Green and Lindsay theory with two relaxation times(GL) Chandrasekharaiah and Tzou theory with dual phase lag(C-T) of thermoelasticity. The Laplace and Fourier transforms techniques are used to solve the problem. As an application, concentrated/uniformly distributed mechanical or thermal sources have been considered to illustrate the utility of the approach. The integral transforms have been inverted by using a numerical inversion technique to obtain the components of displacement, stress, changes in volume fraction field and temperature distribution in the physical domain. The effect of dependence of modulus of elasticity on the components of stress, changes in volume fraction field and temperature distribution are illustrated graphically for a specific model. Different special cases are also deduced.

Thermomechanical interactions in a non local thermoelastic model with two temperature and memory dependent derivatives

Lata, Parveen,Singh, Sukhveer Techno-Press 2020 Coupled systems mechanics Vol.9 No.5

The present investigation is concerned with two-dimensional deformation in a homogeneous isotropic non local thermoelastic solid with two temperatures due to thermomechanical sources. The theory of memory dependent derivatives has been used for the study. The bounding surface is subjected to concentrated and distributed sources (mechanical and thermal sources). The Laplace and Fourier transforms have been used for obtaining the solution to the problem in the transformed domain. The analytical expressions for displacement components, stress components and conductive temperature are obtained in the transformed domain. For obtaining the results in the physical domain, numerical inversion technique has been applied. Numerical simulated results have been depicted graphically for explaining the effects of nonlocal parameter on the components of displacements, stresses and conductive temperature. Some special cases have also been deduced from the present study. The results obtained in the investigation should be useful for new material designers, researchers and physicists working in the field of nonlocal material sciences.

Aerosol size distributions observed at Naiman in the Asian dust source region of Inner Mongolia

Park, S.U.,Park, M.S. Pergamon Press ; Elsevier [distribution] 2014 Atmospheric environment Vol.82 No.-

Aerosol size distributions of observed mass concentrations at the Naiman site in Inner Mongolia that is one of the major Asian dust source regions have been examined for the period from April 2010 to July 2012. The total number of 262 sampled data using the 10-stage quartz crystal microbalance (QCM) cascade impactor is obtained by presetting the frequency changes of 40 Hz during April 2010, 60 Hz for the period of 28 April-16 September 2010 and 70 Hz from 1 November 2010-29 July 2012. The total mass concentrations (PM<SUB>10</SUB>) measured by the QCM cascade impactor are modified to have the same sampling time of 60 min with the help of the 1-h averaged PM<SUB>10</SUB> concentration measured by the beta gauge at the same site. These modified QCM data are classified into the local dust emission case of 196 and the dust advection case of 66. The local dust emission case is defined when the calculated dust flux with the two-level (3 m and 15 m high) measured PM<SUB>10</SUB> concentrations by the beta-gauge is upward and the PM<SUB>10</SUB> concentration measured at 3 m high exceeds 100 μg m<SUP>-3</SUP> while all the rest of QCM sampled data are classified as the dust advection case. The results indicate that the spectral mass concentration distribution of the local dust emission case shows a two-modal distribution with one additional mode of the large particle that cannot be resolved by the QCM cascade impactor whereas that of the advection case reveals a three-modal distribution with one additional unresolved large particle mode. The percent spectral mass concentration distribution of the unresolved mode (stage 1) for the local dust emission case is larger than that for the dust advection case. The modal distributions of both cases can be regressed optimally with log-normal distribution functions. The resolved log-normal distribution functions of the mass concentration distribution by the QCM cascade impactor are found to be the particle mean diameter (the standard deviation) of 0.28 (2.07) and 3.15 μm (1.41 μm) for the local emission case and 0.16 (1.51), 0.60 (1.41) and 2.88 μm (1.38 μm) for the advection case. This clearly suggests that the spectral mass concentration shifts toward the larger particle size for the local emission case.

포장지역 강우유출수에서의 입자성물질의 입도 분포 및 중금속 특성에 관한 연구

박해미,김영준,고석오 한국도로학회 2009 한국도로학회논문집 Vol.11 No.3

Objective of this study was to characterize the particle size distribution(PSD) and quantify the pollutant concentration in highway runoff. Runoff samples during two rainfall events at four road sites in Gyunggio-Do were collected and PSD and associated pollutant distribution was quantified. Also, rainfall amount, flow rate, and other pollutants in samples were analyzed. PSDs in each sample were analyzed and compared with temporal trends of other pollutants. High partial event mean concentrations (PEMC) of particulates were observed at the beginning of runoff and rapid decrease thereafter. Other pollution parameters such as turbidity, TSS, BOD, TN, and TP also have similar temporal runoff trend with the PEMC. Especially PEMC was well correlated with total suspended solids(TSS) and turbidity. Cu, Pb, Zn had high concentration both runoff and sediment. Heavy metals in sediment were strongly bound to fine particles that have the large surface area-to-volume ratios. 본 연구는 고속도로 강우 유출수에서 입도 크기 분포 특성(PSD)을 이해하기 위하여 수행하였다. 경기도내 4곳의 포장도로 지역에서 2번의 강우사상동안 강우유출수 샘플 모니터링을 수행하였고, 시료내 입자의 크기분포를 분석하였다. 또한, 강우량, 유량 및 각 오염물질들을 분석하였다. 시료내 입자의 시간별 변화농도는 강우유출수의 시작 시 높은 값을 보였다가 급속히 감소하였으며 탁도, 총부유물질, BOD, 총질소 및 총인과 같은 오염물질과 유사한 유출경향을 보여주었다. 특히 총부유물질과 탁도와의 높은 상관성을 보여주었다. 강우유출수와 퇴적물내에 포함된 중금속에 있어서 구리, 납, 아연은 높은 농도를 보였으며 대부분의 중금속은 넓이에 대한 부피의 비율이 큰 세립입자에 강하게 결합된 형태로 존재한다.

Axisymmetric deformation in transversely isotropic thermoelastic medium using new modified couple stress theory

Lata, Parveen,Kaur, Harpreet Techno-Press 2019 Coupled systems mechanics Vol.8 No.6

The present study is concerned with the thermoelastic interactions in a two dimensional axisymmetric problem in transversely isotropic thermoelastic solid using new modified couple stress theory without energy dissipation and with two temperatures. The Laplace and Hankel transforms have been employed to find the general solution to the field equations. Concentrated normal force, normal force over the circular region, concentrated thermal source and thermal source over the circular region have been taken to illustrate the application of the approach. The components of displacements, stress, couple stress and conductive temperature distribution are obtained in the transformed domain. The resulting quantities are obtained in the physical domain by using numerical inversion technique. The effect of two temperature varying by taking different values for the two temperature on the components of normal stress, tangential stress, conductive temperature and couple stress are depicted graphically.

Interactions in a transversely isotropic new modified couple stress thermoelastic thick circular plate with two temperature theory

Parveen Lata,Harpreet Kaur Techno-Press 2023 Coupled systems mechanics Vol.12 No.3

This article is an application of new modified couple stress thermoelasticity without energy dissipation in association with two-temperature theory. The upper and lower surfaces of the plate are subjected to an axisymmetric heat supply. The solution is found by using Laplace and Hankel transform techniques. The analytical expressions of displacement components, conductive temperature, stress components and couple stress are computed in transformed domain. Numerical inversion technique has been applied to obtain the results in the physical domain. Numerically simulated results are depicted graphically. The effect of two temperature is shown on the various components.

도시지역 불투수층 지표면 퇴적물질의 입경별 오염물질 특성

이준호,정윤희,방기웅 한국도시환경학회 2009 한국도시환경학회지 Vol.9 No.2

Effect of rotation and inclined load on transversely isotropic magneto thermoelastic solid

Parveen Lata,Iqbal Kaur 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.70 No.2

In present research, we have considered transversely isotropic magneto thermoelastic solid with two temperature and without energy dissipation due to inclined load. The mathematical model has been formulated using Lord-Shulman theory. The Laplace and Fourier transform techniques have been used to find the solution to the problem. The displacement components, stress components and conductive temperature distribution with the horizontal distance are computed in the transformed domain and further calculated in the physical domain using numerical inversion techniques. The effect of rotation and angle of inclination of inclined load is depicted graphically on the resulting quantities.

지하 공동구 내 화재 발생시 유동 특성

김철수,이원섭,김홍식 한국기계기술학회 2003 한국기계기술학회지 Vol.5 No.1