Abstract: The purpose of this paper is to analyze numerically by the three-dimensional finite element method, using ABAQUS calculation code, the mechanical behavior of a unidirectional and multidirectional delaminated stratified composite under mechanical loading in Mode II. This study consists of the determination of the energy release rate G in mode II as well as the distribution of equivalent von Mises stresses along the damaged zone by varying several parameters such as the applied load and the delamination length. It allowed us to deduce that the high energy release rate favors delamination at the free edges of a stratified plate subjected to bending.
Abstract: In this paper, the problem proposed by Von Karman is treated in the attendance of additional flow field effects when the liquid is spaced above the rotating rigid disk. To be more specific, a purely viscous fluid flow yield by rotating rigid disk with Navier’s condition is considered in both magnetohydrodynamic and hydrodynamic frames. The rotating flow regime is manifested with heat source/sink and chemically reactive species. Moreover, the features of thermophoresis and Brownian motion are reported by considering nanofluid model. The flow field formulation is obtained mathematically in terms of high order differential equations. The reduced system of equations is solved numerically through self-coded computational algorithm. The pertinent outcomes are discussed systematically and provided through graphical and tabular practices. A simultaneous way of study makes this attempt attractive in this sense that the article contains dual framework and validation of results with existing work confirms the execution of self-coded algorithm for fluid flow regime over a rotating rigid disk.
Abstract: The traditional k-means algorithm has been widely used as a simple and efficient clustering method. However, the algorithm often converges to local minima for the reason that it is sensitive to the initial cluster centers. In this paper, an algorithm for selecting initial cluster centers on the basis of minimum spanning tree (MST) is presented. The set of vertices in MST with same degree are regarded as a whole which is used to find the skeleton data points. Furthermore, a distance measure between the skeleton data points with consideration of degree and Euclidean distance is presented. Finally, MST-based initialization method for the k-means algorithm is presented, and the corresponding time complexity is analyzed as well. The presented algorithm is tested on five data sets from the UCI Machine Learning Repository. The experimental results illustrate the effectiveness of the presented algorithm compared to three existing initialization methods.
Abstract: Modern agriculture requires productivity, efficiency and quality. Therefore, there is need for agricultural limestone implementation that provides adequate amounts of calcium and magnesium carbonates in order to correct soil acidity. During the limestone process, fine particles (with average size under 400#) are generated. These particles do not have economic value in agricultural and metallurgical sectors due their size. When limestone is used for agriculture purposes, these fine particles can be easily transported by wind generated air pollution. Therefore, briquetting, a mineral processing technique, was used to mitigate this problem resulting in an agglomerated product suitable for agriculture use. Briquetting uses compressive pressure to agglomerate fine particles. It can be aided by agglutination agents, allowing adjustments in shape, size and mechanical parameters of the mass. Briquettes can generate extra profits for mineral industry, presenting as a distinct product for agriculture, and can reduce the environmental liabilities of the fine particles storage or disposition. The produced limestone briquettes were subjected to shatter and water action resistance tests. The results show that after six minutes completely submerged in water, the briquettes where fully diluted, a highly favorable result considering its use for soil acidity correction.
Abstract: Sodium borosilicate glasses doped with different
content of NdF3 mol % have been prepared by rapid quenching
method. Ultrasonic velocities (both longitudinal and shear)
measurements have been carried out at room temperature and at
ultrasonic frequency of 4 MHz. Elastic moduli, Debye temperature,
softening temperature and Poisson's ratio have been obtained as a
function of NdF3 modifier content. Results showed that the elastic
moduli, Debye temperature, softening temperature and Poisson's ratio
have very slight change with the change of NdF3 mol % content.
Based on FTIR spectroscopy and theoretical (Bond compression)
model, quantitative analysis has been carried out in order to obtain
more information about the structure of these glasses. The study
indicated that the structure of these glasses is mainly composed of
SiO4 units with four bridging oxygens (Q4), and with three bridging
and one nonbridging oxygens (Q3).
Abstract: Makishima and Mackenzie model was used to
simulation of acoustic properties (longitudinal and shear ultrasonic
wave velocities, elastic moduli theoretically for many tellurite and
borate glasses. The model was proposed mainly depending on the
values of the experimentally measured density, which are obtained
before. In this search work, we are trying to obtain the values of
densities of amorphous glasses (as the density depends on the
geometry of the network structure of these glasses). In addition, the
problem of simulating the slope of linear regression between the
experimentally determined bulk modulus and the product of packing
density and experimental Young's modulus, were solved in this
search work. The results showed good agreement between the
experimentally measured values of densities and both ultrasonic wave
velocities, and those theoretically determined.
Abstract: The present study is based on the three-dimensional digital analysis by the finite elements method of the mechanical loading effect on the delamination of unidirectional and multidirectional stratified composites. The aim of this work is the determination of the release energy rate G in mode I and the Von Mises equivalent constraint distribution along the damaged area under the influence of several parameters such as the applied load and the delamination size. The results obtained in this study show that the unidirectional composite laminates have better mechanical resistance one the loading line than the multidirectional composite laminates.
Abstract: Freshly laid eggs from green turtles, Chelonia mydas,
were randomly collected from Ras Al-Hadd Reserve, Oman.
Eggshells taken from eggs and sand collected from the body chamber
were analyzed for eight heavy metals (Al, Br, Cd, Co, Cu, Fe, S, and
Zn) using inductively coupled plasma mass spectrometry (ICP).
Heavy metal concentrations varied significantly (P
Abstract: Iron is an essential nutrient with limited
bioavailability. Nutritional anemia caused mainly by iron deficiency
is the most recognized nutritional problem in both countries as well
as affluent societies. Rice (Oryza sativa L.) has become the most
important cereal crop for the improvement of human health due to the
starch, protein, oil, and the majority of micronutrients, particularly in
Asian countries. In this study, the iron availability and profile lipid
were evaluated for the extracts from Cibeusi varieties (black rices) of
ancient rice brans.
Results: The quality of K, B, R, E diets groups shows the same
effect on the growth of rats. Hematocrit and MCHC levels of rats fed
K, B, R and E diets were not significantly (P
Abstract: Leukaemia is a blood cancer disease that contributes
to the increment of mortality rate in Malaysia each year. There are
two main categories for leukaemia, which are acute and chronic
leukaemia. The production and development of acute leukaemia cells
occurs rapidly and uncontrollable. Therefore, if the identification of
acute leukaemia cells could be done fast and effectively, proper
treatment and medicine could be delivered. Due to the requirement of
prompt and accurate diagnosis of leukaemia, the current study has
proposed unsupervised pixel segmentation based on clustering
algorithm in order to obtain a fully segmented abnormal white blood
cell (blast) in acute leukaemia image. In order to obtain the
segmented blast, the current study proposed three clustering
algorithms which are k-means, fuzzy c-means and moving k-means
algorithms have been applied on the saturation component image.
Then, median filter and seeded region growing area extraction
algorithms have been applied, to smooth the region of segmented
blast and to remove the large unwanted regions from the image,
respectively. Comparisons among the three clustering algorithms are
made in order to measure the performance of each clustering
algorithm on segmenting the blast area. Based on the good sensitivity
value that has been obtained, the results indicate that moving kmeans
clustering algorithm has successfully produced the fully
segmented blast region in acute leukaemia image. Hence, indicating
that the resultant images could be helpful to haematologists for
further analysis of acute leukaemia.
Abstract: This paper reveals the interaction between hydrogen
and surface stress in austenitic stainless steel by X-ray diffraction
stress measurement and thermal desorption analysis before and after
being charged with hydrogen. The surface residual stress was varied
by surface finishing using several disc polishing agents. The obtained
results show that the residual stress near surface had a significant
effect on hydrogen absorption behavior, that is, tensile residual stress
promoted the hydrogen absorption and compressive one did opposite.
Also, hydrogen induced equi-biaxial stress and this stress has a linear
correlation with hydrogen content.
Abstract: Background and objectives: Most of the agricultural products are processed by blanching. Blanching can increase antioxidant activity in white saffron products. The objective of this research were to determine antioxidant activity, to identify, and to measure changes in phenolic substances of fresh and blanched white saffron rhizomes (Curcuma mangga Val.). Methods: White saffron rhizomes were peeled, washed and blanched in boiling water containing 0% or 0.05% citric acid solution for 5 and 10 minutes. Samples were extracted using methanol, rotaevaporated, and freezedried. Dried extract was determined antioxidant activity by DPPH method, identified and quantified for the phenolic substances by High Performance Liquid Chromatography (HPLC) equipped with coloumn C18 and Photodiode-array detector (PAD). Result: This research showed that the quantity of the 6 phenolic substances identified in blanched white saffron in citric acid solution increased significantly compared to that of the non-blanched. Blanching white saffron in 0.05% citric acid media for 5 minutes increased its antioxidant activity, and total phenolic content. Conclusions: The identified phenolic substances of white saffron were Gallic Acid (GA), Catechin (C), Epicatechin (EC), Epigallocatechin (EGC), Epigallocatechingallat (EGCG) and Gallocatechingallat (GCG). The blanched white saffron contained C and EGCG significantly higher than that of fresh rhizomes.
Abstract: In this study, the Taguchi method was used to optimize the effect of HALO structure or halo implant variations on threshold voltage (VTH) and leakage current (ILeak) in 45nm p-type Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) device. Besides halo implant dose, the other process parameters which used were Source/Drain (S/D) implant dose, oxide growth temperature and silicide anneal temperature. This work was done using TCAD simulator, consisting of a process simulator, ATHENA and device simulator, ATLAS. These two simulators were combined with Taguchi method to aid in design and optimize the process parameters. In this research, the most effective process parameters with respect to VTH and ILeak are halo implant dose (40%) and S/D implant dose (52%) respectively. Whereas the second ranking factor affecting VTH and ILeak are oxide growth temperature (32%) and halo implant dose (34%) respectively. The results show that after optimizations approaches is -0.157V at ILeak=0.195mA/μm.
Abstract: In the globalization process, when the struggle for minds and values of the people is taking place, the impact of the virtual space can cause unexpected effects and consequences in the process of adjustment of young people in this world. Their special significance is defined by unconscious influence on the underlying process of meaning and therefore the values preached by them are much more effective and affect both the personal characteristics and the peculiarities of adjustment process. Related to this the challenge is to identify factors influencing the reflection characteristics of virtual subjects and measures their impact on the personal characteristics of the students.
Abstract: In this paper a multi-objective nonlinear programming
model of cellular manufacturing system is presented which minimize
the intercell movements and maximize the sum of reliability of cells.
We present a genetic approach for finding efficient solutions to the
problem of cell formation for products having multiple routings.
These methods find the non-dominated solutions and according to
decision makers prefer, the best solution will be chosen.
Abstract: This paper presents an exact analytical model for
optimizing stability of thin-walled, composite, functionally graded
pipes conveying fluid. The critical flow velocity at which divergence
occurs is maximized for a specified total structural mass in order to
ensure the economic feasibility of the attained optimum designs. The
composition of the material of construction is optimized by defining
the spatial distribution of volume fractions of the material
constituents using piecewise variations along the pipe length. The
major aim is to tailor the material distribution in the axial direction so
as to avoid the occurrence of divergence instability without the
penalty of increasing structural mass. Three types of boundary
conditions have been examined; namely, Hinged-Hinged, Clamped-
Hinged and Clamped-Clamped pipelines. The resulting optimization
problem has been formulated as a nonlinear mathematical
programming problem solved by invoking the MatLab optimization
toolbox routines, which implement constrained function
minimization routine named “fmincon" interacting with the
associated eigenvalue problem routines. In fact, the proposed
mathematical models have succeeded in maximizing the critical flow
velocity without mass penalty and producing efficient and economic
designs having enhanced stability characteristics as compared with
the baseline designs.
Abstract: This paper presents a generalized formulation for the
problem of buckling optimization of anisotropic, radially graded,
thin-walled, long cylinders subject to external hydrostatic pressure.
The main structure to be analyzed is built of multi-angle fibrous
laminated composite lay-ups having different volume fractions of the
constituent materials within the individual plies. This yield to a
piecewise grading of the material in the radial direction; that is the
physical and mechanical properties of the composite material are
allowed to vary radially. The objective function is measured by
maximizing the critical buckling pressure while preserving the total
structural mass at a constant value equals to that of a baseline
reference design. In the selection of the significant optimization
variables, the fiber volume fractions adjoin the standard design
variables including fiber orientation angles and ply thicknesses. The
mathematical formulation employs the classical lamination theory,
where an analytical solution that accounts for the effective axial and
flexural stiffness separately as well as the inclusion of the coupling
stiffness terms is presented. The proposed model deals with
dimensionless quantities in order to be valid for thin shells having
arbitrary thickness-to-radius ratios. The critical buckling pressure
level curves augmented with the mass equality constraint are given
for several types of cylinders showing the functional dependence of
the constrained objective function on the selected design variables. It
was shown that material grading can have significant contribution to
the whole optimization process in achieving the required structural
designs with enhanced stability limits.