In this paper, the steady Falkner-Skan solution for gravity-driven film flow of a micropolar fluid is theoretically investigated. The resulting nonlinear ordinary differential equations are solved numerically using an implicit finite-difference scheme. The results obtained for the skin friction coefficient as well as the velocity and microrotation or angular velocity profiles are shown in table and figures for different values of the material or micropolar parameter K.
In this paper we present a new line search method known as the HBFGS method, which uses the search direction of the conjugate gradient method with the quasi-Newton updates. The Broyden-Fletcher-Goldfarb-Shanno (BFGS) update is used as approximation of the Hessian for the methods. The new algorithm is compared with the BFGS method in terms of iteration counts and CPU-time. Our numerical analysis provides strong evidence that the proposed HBFGS method is more efficient than the ordinary BFGS method. Besides, we also prove that the new algorithm is globally convergent.
We consider a vector nonlinear differential equation of fourth order with a constant delay. We establish new sufficient conditions, which guarantee the instability of the zero solution of that equation. An example is given to illustrate the theoretical analysis made in this paper
In this paper, an improved trigonometrically fitted zero-dissipative explicit two-step hybrid method with fifth algebraic
order is derived. The method is applied to several problems where by the solutions are oscillatory in nature. Numerical
results obtained are compared with existing methods in the scientific literature. The comparison shows that the new
method is more effective and efficient than the existing methods of the same order.
Quality of bond between layers of asphaltic concrete course is a key element to ensure the performance of a modern asphalt pavement. A proper interlayer bond ensures the structural integrity of the pavement and prevents possible distresses from occurring within the designed service life. In Malaysia, delamination is a common distress related to insufficient degree of adhesion though slippage failure can be occasionally encountered. Generally, bond development is closely related to the design factors and construction factors. This paper however focused on the construction factors only, hoping to provide some useful information which might be overlooked by the contractors during construction but is of extreme important especially in enhancing the bond development in the asphalt layers. The construction factors in particular interest discussed in this paper include curing time of asphalt emulsion, surface condition of a pavement and technology and quality of workmanship and construction. It is important to note that both design factors and construction factors are inter-related in optimizing the degree of adhesion. Thus, all factors need to be carefully identified and fulfilled in order to maximize the bond strength between pavement surfacing layers for a better quality and longer service life of pavement in Malaysia.
A high-order uniform Cartesian grid compact finite difference scheme for the Goursat problem is developed. The basic idea of high-order compact schemes is to find the compact approximations to the derivatives terms by differentiating centrally the governing equations. Our compact scheme will approximate the derivative terms by involving the higher terms and reducing the number of grid points. The compact finite difference scheme is given for general form of the Goursat problem in uniform domain and illustrates the performance by applying a linear problem. Numerical experiments have been conducted with the new scheme and encouraging results have been obtained. In this paper we present the compact finite difference scheme for the Goursat problem. With the aid of computational software the scheme was programmed for determining the relative errors of linear Goursat problem.
Numerical application helps researchers in simulating various problems and used for solving partial differential equation. Half sweep and quarter sweep approach have been applied onto iterative method to gain approximation solution. In this paper, the implementation of full sweep successive over relaxation (FSSOR), half sweep successive over relaxation (HSSOR) and quarter sweep successive over relaxation (QSSOR) methods and full sweep accelerated over relaxation (FSAOR), half sweep accelerated over relaxation (HSAOR) and quarter sweep accelerated over relaxation (QSAOR) for its numerical engines are shown. QSSOR and QSAOR method was the fastest among FSSOR, HSSOR, FSAOR and HSAOR methods. Additionally, QSAOR performance is more accurate than QSSOR.
In this paper, the homotopy decomposition method with a modified definition of beta fractional derivative is adopted
to find approximate solutions of higher-dimensional time-fractional diffusion equations. To apply this method, we find
the modified beta integral for both sides of a fractional differential equation first, then using homotopy decomposition
method we can obtain the solution of the integral equation in a series form. We compare the solutions obtained by the
proposed method with the exact solutions obtained using fractional variational homotopy perturbation iteration method
via modified Riemann-Liouville derivative. The comparison shows that the results are in a good agreement.
This paper reviewed the aspect of fatigue approaches and analysis in a fibre reinforced composite materials which have been done by researchers worldwide. The aim of this review is to provide a better picture on analytical approaches that are presently available for predicting fatigue life in composite materials. This review also proposes a new interpretation of available theories and identifies area in fatigue of natural fibre reinforced composite materials. Thus, it was concluded there are still very limited studies on fatigue analysis of natural fibre reinforced composite materials, especially using non-destructive technique (NDT) methods and a new mathematical modelling on fatigue should be formulated.
In this paper, an implicit 2-point Block Backward Differentiation formula (BBDF) method was considered for solving Delay Differential Equations (DDEs). The method was implemented by using a constant stepsize via Newton Iteration. This implicit block method was expected to produce two points simultaneously. The efficiency of the method was compared with the existing classical 1-point Backward Differentiation Formula (BDF) in terms of execution time and accuracy.
Compressive residual stress, induced by mechanical surface treatment, may relax during component
operation life, due to thermal or mechanical mechanism. Fatigue life prediction for the components which have residual stress will be misled and inaccurately predicted the phenomenon of residual stress relaxation is not considered. Despite putting an effort on incorporating the residual stress relaxation, the issues remain concerned with the technical challenge of measuring and quantifying
the magnitude of residual stress relaxation as well as redistribution during the loading cycling itself.
In this paper, the residual stress relaxation and its models were reviewed and discussed to picture
the best knowledge related to this topic, i.e. whether relaxation is a cause or an effect.
The paper presents a simulation work conducted on the elastomer subjected to cyclic loads. A 3D finite element model of elastomer specimen, in accordance to ASTM D412, was developed using CATIA and ANSYS commercial finite element (FEM) packages. Fatigue life predicted from the simulation was compared with well-documented published data and it showed an acceptable agreement. Meanwhile, the simulated strain-life results are slightly lower than the experimental data. Several factors which potentially influenced the variations of the results were noted. Finally, some recommendations are offered at the end of this study to further improve the simulation
In the present paper we provide a construction of Quantum Markov chain on a Cayley tree. Moreover, we give a concrete example of such chains, which is shift invariant and has the clustering property
Mass valuation of properties is important for purposes like property tax, price indices construction, and understanding market dynamics. There are several ways that the mass valuation can be carried out. This paper reviews the conventional MRA and several other advanced methods such as SAR, Kriging, GWR, and MWR. SAR and Kriging are good for modeling spatial dependence while GWR and MWR are good for modeling spatial heterogeneity. The difference between SAR and Kriging is the calculation of weights. Kriging weights are based on the spatial dependence or so called the semi-variogram analysis of the price data whereas the weights in SAR are based on the spatial contiguity between the sample data. MWR and GWR are special types of regression where study region is subdivided into local sections to increase the accuracy of prediction through neutralizing the heterogeneity of autocorrelations. MWR assigns equal weights for observations within a window while GWR uses distance decay functions. The merits and drawbacks of each method are discussed.
This paper presents the evaluation of integrated partial match query in Geographic Information Retrieval (GIR). To facilitate the evaluation, Kuala Lumpur tourist related data is used as test collection and is stored in SuperWeb, a map server. Then the map server is customized to enhance its query capability to recognize word in partial or case sensitive between layers of spatial data. Query keyword is tested using the system and results are evaluated using experiments on sample data. Findings show that integrated partial match query provides more flexibility to tourist in determining search results.
Maintenance is a vital system in a manufacturing company. The maintenance objectives are to ensure that the machine is in good condition, serviceable and safe to be operated in producing quality products. However, the system usually imposes a high cost system due to its ineffective activities. Therefore, this paper was written to review the factors affecting the maintenance effectiveness and methods used to measure its performance. In this paper, maintenance performance measurement methods are categorized into three groups, based on holistic, machine, and value factors. Each group is discussed based on the principles and techniques of the maintenance performance measurement methods, along with the example of its applications in the industry. The most common methods used are the holistic approach, overall equipment effectiveness (OEE), and balance score-card (BSC). These various methods have their own benefits and drawbacks, according to the area of measurement.
Soil properties are very crucial for civil engineers to differentiate one type of soil from another and to predict its mechanical behavior. However, it is not practical to measure soil properties at all the locations at a site. In this paper, an estimator is derived to estimate the unknown values for soil properties from locations where soil samples were not collected. The estimator is obtained by combining the concept of the ‘Inverse Distance Method’ into the technique of ‘Kriging’. The method of Lagrange Multipliers is applied in this paper. It is shown that the estimator derived in this paper is an unbiased estimator. The partiality of the estimator with respect to the true value is zero. Hence, the estimated value will be equal to the true value of the soil property. It is also shown that the variance between the estimator and the soil property is minimized. Hence, the distribution of this unbiased estimator with minimum variance spreads the least from the true value. With this characteristic of minimum variance unbiased estimator, a high accuracy estimation of soil property could be obtained.
The Lembah Bujang archeological complex near Sungai Petani, Kedah consists of various structures constructed at different times and spread over a wide area. This paper reports on the thermoluminescence (TL) dating of one of these structures. The structure was found to be 350 ± 90 yrs old. This is very young as compared with other structures that are from the 4th to the 16th centuries. This structure is suspected to be remnant of a Muslim Mosque whereas the other structures were Hindu and Buddist temples.
This paper presents an overview topic of layered and laminated fibre composites. The review presents an investigation on the effect of varying the properties of fibre and the matrix of layered and laminated composites and identifies the fundamental parameters determining ballistic impact protection. The advantages of layered and laminated reinforced composites with different thicknesses for further enhancing ballistic penetration resistance of the laminated fibre composite have been reviewed. Lamination of multiple layers of composite material can give better ballistic performance.
This paper presents the numerical modelling techniques for the simulation of the energy conversion chain from wave to electricity in an Oscillating Water Column (OWC) equipped with a full-scaled self rectifying turbine. The performance of the OWC device has been assessed for the stand-alone power system of a typical Irish climatic wave condition. The results showed that the overall performance of the complete device depends on the level of turbine damping, which in turn depends on the wave climate, especially the significant wave height. Furthermore, turbine efficiency predicted using quasi-steady showed qualitatively favourable agreement with the experimental results.