**Commenced**in January 2007

**Frequency:**Monthly

**Edition:**International

**Paper Count:**1588

# Search results for: thermal gradient.

##### 1588 Simulation of Effect of Current Stressing on Reliability of Solder Joints with Cu-Pillar Bumps

**Authors:**
Y. Li,
Q. S. Zhang,
H. Z. Huang,
B. Y. Wu

**Abstract:**

**Keywords:**
Simulation,
Cu-pillar bumps,
Electromigration,
Thermomigration.

##### 1587 Thermal Cracking Respone of Reinforced Concrete Beam to Gradient Temperature

**Authors:**
L. Dahmani,
M.Kouane

**Abstract:**

**Keywords:**
Cracking,
Gradient Temperature,
Reinforced Concrete beam,
Thermo-mechanical analysis.

##### 1586 Effect of Linear Thermal Gradient on Steady-State Creep Behavior of Isotropic Rotating Disc

**Authors:**
Minto Rattan,
Tania Bose,
Neeraj Chamoli

**Abstract:**

**Keywords:**
Creep,
isotropic,
steady-state,
thermal gradient.

##### 1585 Effect of Thermal Radiation on Temperature Variation in 2-D Stagnation-Point flow

**Authors:**
Vai Kuong Sin

**Abstract:**

Non-isothermal stagnation-point flow with consideration of thermal radiation is studied numerically. A set of partial differential equations that governing the fluid flow and energy is converted into a set of ordinary differential equations which is solved by Runge-Kutta method with shooting algorithm. Dimensionless wall temperature gradient and temperature boundary layer thickness for different combinaton of values of Prandtl number Pr and radiation parameter NR are presented graphically. Analyses of results show that the presence of thermal radiation in the stagnation-point flow is to increase the temperature boundary layer thickness and decrease the dimensionless wall temperature gradient.

**Keywords:**
Stagnation-point flow,
Similarity solution,
Thermal radiation.

##### 1584 Particle Simulation of Rarefied Gas Flows witha Superimposed Wall Surface Temperature Gradient in Microgeometries

**Authors:**
V. Azadeh Ranjbar

**Abstract:**

**Keywords:**
DSMC,
Thermal transpiration,
Thermal creep,
MEMS,
Knudsen Compressor.

##### 1583 Thermal Buckling of Rectangular FGM Plate with Variation Thickness

**Authors:**
Mostafa Raki,
Mahdi Hamzehei

**Abstract:**

Equilibrium and stability equations of a thin rectangular plate with length a, width b, and thickness h(x)=C1x+C2, made of functionally graded materials under thermal loads are derived based on the first order shear deformation theory. It is assumed that the material properties vary as a power form of thickness coordinate variable z. The derived equilibrium and buckling equations are then solved analytically for a plate with simply supported boundary conditions. One type of thermal loading, uniform temperature rise and gradient through the thickness are considered, and the buckling temperatures are derived. The influences of the plate aspect ratio, the relative thickness, the gradient index and the transverse shear on buckling temperature difference are all discussed.

**Keywords:**
Stability of plate,
thermal buckling,
rectangularplate,
functionally graded material,
first order shear deformationtheory.

##### 1582 Mechanical and Thermal Stresses in Functionally Graded Cylinders

**Authors:**
A. Kurşun,
E. Kara,
E. Çetin,
Ş. Aksoy,
A. Kesimli

**Abstract:**

In this study, thermal elastic stress distribution occurred on long hollow cylinders made of functionally graded material (FGM) was analytically defined under thermal, mechanical and thermo mechanical loads. In closed form solutions for elastic stresses and displacements are obtained analytically by using the infinitesimal deformation theory of elasticity. It was assumed that elasticity modulus, thermal expansion coefficient and density of cylinder materials could change in terms of an exponential function as for that Poisson’s ratio was constant. A gradient parameter n is chosen between - 1 and 1. When n equals to zero, the disc becomes isotropic. Circumferential, radial and longitudinal stresses in the FGMs cylinders are depicted in the figures. As a result, the gradient parameters have great effects on the stress systems of FGMs cylinders.

**Keywords:**
Functionally graded materials,
hollow cylinder,
thermoelasticity,
thermomechanical load.

##### 1581 Constructal Enhancement of Fins Design Integrated to Phase Change Materials

**Authors:**
Varun Joshi,
Manish K. Rathod

**Abstract:**

**Keywords:**
Constructal theory,
enthalpy porosity approach,
phase change materials,
fins.

##### 1580 Mathematical Modeling of the Working Principle of Gravity Gradient Instrument

**Authors:**
Danni Cong,
Meiping Wu,
Hua Mu,
Xiaofeng He,
Junxiang Lian,
Juliang Cao,
Shaokun Cai,
Hao Qin

**Abstract:**

**Keywords:**
Gravity gradient,
accelerometer,
gravity gradient sensor,
single-axis rotation modulation.

##### 1579 Simulating Gradient Contour and Mesh of a Scalar Field

**Authors:**
Usman Ali Khan,
Bismah Tariq,
Khalida Raza,
Saima Malik,
Aoun Muhammad

**Abstract:**

**Keywords:**
MATLAB,
Gradient,
Contour,
Scalar Field,
Mesh

##### 1578 Design and Microfabrication of a High Throughput Thermal Cycling Platform with Various Annealing Temperatures

**Authors:**
Sin J. Chen,
Jyh J. Chen

**Abstract:**

**Keywords:**
Polymerase chain reaction,
thermal cycles,
temperature gradient,
micro-fabrication.

##### 1577 Yield Onset of Thermo-Mechanical Loading of FGM Thick Walled Cylindrical Pressure Vessels

**Authors:**
S. Ansari Sadrabadi,
G. H. Rahimi

**Abstract:**

In this paper, thick walled Cylindrical tanks or tubes made of functionally graded material under internal pressure and temperature gradient are studied. Material parameters have been considered as power functions. They play important role in the elastoplastic behavior of these materials. To clarify their role, different materials with different parameters have been used under temperature gradient. Finally, their effect and loading effect have been determined in first yield point. Also, the important role of temperature gradient was also shown. At the end the study has been results obtained from changes in the elastic modulus and yield stress. Also special attention is also given to the effects of this internal pressure and temperature gradient in the creation of tensile and compressive stresses.

**Keywords:**
FGM,
Cylindrical pressure tubes,
Small deformation
theory,
Yield onset,
Thermal loading.

##### 1576 A Clock Skew Minimization Technique Considering Temperature Gradient

**Authors:**
Se-Jin Ko,
Deok-Min Kim,
Seok-Yoon Kim

**Abstract:**

**Keywords:**
clock,
clock-skew,
temperature,
thermal.

##### 1575 A New Modification of Nonlinear Conjugate Gradient Coefficients with Global Convergence Properties

**Authors:**
Ahmad Alhawarat,
Mustafa Mamat,
Mohd Rivaie,
Ismail Mohd

**Abstract:**

**Keywords:**
Conjugate gradient method,
conjugate gradient
coefficient,
global convergence.

##### 1574 Long Term Stability of an Experimental Insulated-Model Salinity-Gradient Solar Pond

**Authors:**
N. W. K. Jayatissa,
R. Attalage,
Prabath Hewageegana,
P. A. A. Perera,
M. A. Punyasena

**Abstract:**

Per capita energy usage in any country is exponentially increasing with their development. As a result, the country’s dependence on the fossil fuels for energy generation is also increasing tremendously creating economic and environmental concerns. Tropical countries receive considerable amount of solar radiation throughout the year, use of solar energy with different energy storage and conversion methodologies is a viable solution to minimize the ever increasing demand for the depleting fossil fuels. Salinity gradient solar pond is one such solar energy application. This paper reports the characteristics and performance of a thermally insulated, experimental salinity-gradient solar pond, built at the premises of the University of Kelaniya, Sri Lanka. Particular stress is given to the behavior of the evolution of the three layer structure exist at the stable state of a salinity gradient solar pond over a long period of time, under different environmental conditions. The operational procedures required to maintain the long term thermal stability are also reported in this article.

**Keywords:**
Salt-gradient,
solar pond,
solar radiation,
renewable energy.

##### 1573 Research on the Correlation of the Fluctuating Density Gradient of the Compressible Flows

**Authors:**
Yasuo Obikane

**Abstract:**

**Keywords:**
Turbulence Modeling ,
Density Gradient Correlation,
Compressible

##### 1572 Segmentation of Noisy Digital Images with Stochastic Gradient Kernel

**Authors:**
Abhishek Neogi,
Jayesh Verma,
Pinaki Pratim Acharjya

**Abstract:**

**Keywords:**
Image segmentation,
edge Detection,
noisy images,
spatialfilters,
stochastic gradient kernel.

##### 1571 Dynamic Measurement System Modeling with Machine Learning Algorithms

**Authors:**
Changqiao Wu,
Guoqing Ding,
Xin Chen

**Abstract:**

**Keywords:**
Dynamic system modeling,
neural network,
normal
equation,
second order gradient descent.

##### 1570 Green Function and Eshelby Tensor Based on Mindlin’s 2nd Gradient Model: An Explicit Study of Spherical Inclusion Case

**Authors:**
A. Selmi,
A. Bisharat

**Abstract:**

Using Fourier transform and based on the Mindlin's 2^{nd} gradient model that involves two length scale parameters, the Green's function, the Eshelby tensor, and the Eshelby-like tensor for a spherical inclusion are derived. It is proved that the Eshelby tensor consists of two parts; the classical Eshelby tensor and a gradient part including the length scale parameters which enable the interpretation of the size effect. When the strain gradient is not taken into account, the obtained Green's function and Eshelby tensor reduce to its analogue based on the classical elasticity. The Eshelby tensor in and outside the inclusion, the volume average of the gradient part and the Eshelby-like tensor are explicitly obtained. Unlike the classical Eshelby tensor, the results show that the components of the new Eshelby tensor vary with the position and the inclusion dimensions. It is demonstrated that the contribution of the gradient part should not be neglected.

**Keywords:**
Eshelby tensor,
Eshelby-like tensor,
Green’s function,
Mindlin’s 2nd gradient model,
Spherical inclusion.

##### 1569 Flexural Strength Design of RC Beams with Consideration of Strain Gradient Effect

**Authors:**
Mantai Chen,
Johnny Ching Ming Ho

**Abstract:**

The stress-strain relationship of concrete under flexure is one of the essential parameters in assessing ultimate flexural strength capacity of RC beams. Currently, the concrete stress-strain curve in flexure is obtained by incorporating a constant scale-down factor of 0.85 in the uniaxial stress-strain curve. However, it was revealed that strain gradient would improve the maximum concrete stress under flexure and concrete stress-strain curve is strain gradient dependent. Based on the strain-gradient-dependent concrete stress-strain curve, the investigation of the combined effects of strain gradient and concrete strength on flexural strength of RC beams was extended to high strength concrete up to 100 MPa by theoretical analysis. As an extension and application of the authors’ previous study, a new flexural strength design method incorporating the combined effects of strain gradient and concrete strength is developed. A set of equivalent rectangular concrete stress block parameters is proposed and applied to produce a series of design charts showing that the flexural strength of RC beams are improved with strain gradient effect considered.

**Keywords:**
Beams,
Equivalent concrete stress block,
Flexural strength,
Strain gradient.

##### 1568 Learning Flexible Neural Networks for Pattern Recognition

**Authors:**
A. Mirzaaghazadeh,
H. Motameni,
M. Karshenas,
H. Nematzadeh

**Abstract:**

**Keywords:**
Back propagation,
Flexible,
Gradient,
Learning,
Neural network,
Pattern recognition.

##### 1567 Hybrid Gravity Gradient Inversion-Ant Colony Optimization Algorithm for Motion Planning of Mobile Robots

**Authors:**
Meng Wu

**Abstract:**

Motion planning is a common task required to be fulfilled by robots. A strategy combining Ant Colony Optimization (ACO) and gravity gradient inversion algorithm is proposed for motion planning of mobile robots. In this paper, in order to realize optimal motion planning strategy, the cost function in ACO is designed based on gravity gradient inversion algorithm. The obstacles around mobile robot can cause gravity gradient anomalies; the gradiometer is installed on the mobile robot to detect the gravity gradient anomalies. After obtaining the anomalies, gravity gradient inversion algorithm is employed to calculate relative distance and orientation between mobile robot and obstacles. The relative distance and orientation deduced from gravity gradient inversion algorithm is employed as cost function in ACO algorithm to realize motion planning. The proposed strategy is validated by the simulation and experiment results.

**Keywords:**
Motion planning,
gravity gradient inversion algorithm,
ant colony optimization.

##### 1566 Impact of Viscous and Heat Relaxation Loss on the Critical Temperature Gradients of Thermoacoustic Stacks

**Authors:**
Zhibin Yu,
Artur J. Jaworski,
Abdulrahman S. Abduljalil

**Abstract:**

**Keywords:**
Critical temperature gradient,
heat relaxation,
stack,
viscous effect.

##### 1565 A Refined Nonlocal Strain Gradient Theory for Assessing Scaling-Dependent Vibration Behavior of Microbeams

**Authors:**
Xiaobai Li,
Li Li,
Yujin Hu,
Weiming Deng,
Zhe Ding

**Abstract:**

**Keywords:**
Euler-Bernoulli Beams,
free vibration,
higher order
inertia,
nonlocal strain gradient theory,
velocity gradient.

##### 1564 Comparison of Three Versions of Conjugate Gradient Method in Predicting an Unknown Irregular Boundary Profile

**Authors:**
V. Ghadamyari,
F. Samadi,
F. Kowsary

**Abstract:**

**Keywords:**
Boundary elements,
Conjugate Gradient Method,
Inverse Geometry Problem,
Sensitivity equation.

##### 1563 An Improved Conjugate Gradient Based Learning Algorithm for Back Propagation Neural Networks

**Authors:**
N. M. Nawi,
R. S. Ransing,
M. R. Ransing

**Abstract:**

The conjugate gradient optimization algorithm is combined with the modified back propagation algorithm to yield a computationally efficient algorithm for training multilayer perceptron (MLP) networks (CGFR/AG). The computational efficiency is enhanced by adaptively modifying initial search direction as described in the following steps: (1) Modification on standard back propagation algorithm by introducing a gain variation term in the activation function, (2) Calculation of the gradient descent of error with respect to the weights and gains values and (3) the determination of a new search direction by using information calculated in step (2). The performance of the proposed method is demonstrated by comparing accuracy and computation time with the conjugate gradient algorithm used in MATLAB neural network toolbox. The results show that the computational efficiency of the proposed method was better than the standard conjugate gradient algorithm.

**Keywords:**
Adaptive gain variation,
back-propagation,
activation function,
conjugate gradient,
search direction.

##### 1562 Nonlinear Thermal Expansion Model for SiC/Al

**Authors:**
T.R. Sahroni,
S. Sulaiman,
I. Romli,
M.R. Salleh,
H.A. Ariff

**Abstract:**

**Keywords:**
Nonlinear,
thermal,
fibre reinforced,
metal matrixcomposites

##### 1561 Conjugate Gradient Algorithm for the Symmetric Arrowhead Solution of Matrix Equation AXB=C

**Authors:**
Minghui Wang,
Luping Xu,
Juntao Zhang

**Abstract:**

*AXB=C*and the associate optimal approximation problem are considered for the symmetric arrowhead matrix solutions in the premise of consistency. The convergence results of the method are presented. At last, a numerical example is given to illustrate the efficiency of this method.

**Keywords:**
Iterative method,
symmetric arrowhead matrix,
conjugate gradient algorithm.

##### 1560 Advanced Neural Network Learning Applied to Pulping Modeling

**Authors:**
Z. Zainuddin,
W. D. Wan Rosli,
R. Lanouette,
S. Sathasivam

**Abstract:**

This paper reports work done to improve the modeling of complex processes when only small experimental data sets are available. Neural networks are used to capture the nonlinear underlying phenomena contained in the data set and to partly eliminate the burden of having to specify completely the structure of the model. Two different types of neural networks were used for the application of pulping problem. A three layer feed forward neural networks, using the Preconditioned Conjugate Gradient (PCG) methods were used in this investigation. Preconditioning is a method to improve convergence by lowering the condition number and increasing the eigenvalues clustering. The idea is to solve the modified odified problem M-1 Ax= M-1b where M is a positive-definite preconditioner that is closely related to A. We mainly focused on Preconditioned Conjugate Gradient- based training methods which originated from optimization theory, namely Preconditioned Conjugate Gradient with Fletcher-Reeves Update (PCGF), Preconditioned Conjugate Gradient with Polak-Ribiere Update (PCGP) and Preconditioned Conjugate Gradient with Powell-Beale Restarts (PCGB). The behavior of the PCG methods in the simulations proved to be robust against phenomenon such as oscillations due to large step size.

**Keywords:**
Convergence,
pulping modeling,
neural networks,
preconditioned conjugate gradient.

##### 1559 Using the Transient Plane Source Method for Measuring Thermal Parameters of Electroceramics

**Authors:**
Peter Krupa,
Svetozár Malinarič

**Abstract:**

Transient plane source method has been used to measure the thermal diffusivity and thermal conductivity of a compact isostatic electroceramics at room temperature. The samples were fired at temperatures from 100 up to 1320 degrees Celsius in steps of 50. Bulk density and specific heat capacity were also measured with their corresponding standard uncertainties. The results were compared with further thermal analysis (dilatometry and thermogravimetry). Structural processes during firing were discussed.

**Keywords:**
TPS method,
thermal conductivity,
thermal diffusivity,
thermal analysis,
electroceramics,
firing.