Science and Technology Research Institute for Defence (STRIDE),
Ministry of Defence, Malaysia.
Mountains are generally viewed as Boolean objects, whereby a terrain can be divided into two classes: mountain and non-mountain. However, recent studies have shown that mountains are more suitable to be viewed as fuzzy objects, whereby a mountain is defined as a region in the continuum of variation of the surface of the earth. In this paper, the fuzzy classification of mountains extracted from multiscale DEMs is performed. First, the lifting scheme is used to generate multiscale DEMs. Mountains extraction is implemented on the generated multiscale DEMs. Fuzzy classification is performed based on by the average of Boolean memberships of the extracted mountains features over the scales of measurement. The proposed fuzzy classification method is useful for statistical analyses and determination of sample schemes.
Studies on Carbon Dioxide Laser-Malaysian Light Hardwood (Shorea uliginosa, Dyera costulata) and Plywood Interactions using Ultrasound, Scanning Electron Microscope and Energy Dispersive X-ray
Izyani Karudin, Mohamad Suhaimi Jaafar, Khalid M.Omar Al-Hadithi and Nor Fadhlin Jaafar
Medical Physics Research, School of Physics, Universiti Sains Malaysia, 11800, Minden, Penang, Malaysia
Processing of wood by conventional mechanical tools like saws or planes leaves behind a layer of squeezed wood only slightly adhering to the solid wood surface. Laser wood cutting could improve the quality of cutting, obtaining precise and narrow cuts with little or no distortion to the surrounding base material. The aim of this work is to provide a phenomenological understanding of interactions between an intense CW CO2 laser with Malaysian light hardwoods. The capability of a 5.2 W low power CO2 laser in cutting meranti bakau (Shorea uliginosa), plywood and jelutung (Dyera costulata) has been studied. The woods were irradiated at different incident angles of ranged 0°, 10°, 20°, 30°, 40° and 50° and distances from laser source from 5 cm up to 30 cm. Surface morphology observation with SEM as well as element and compounds identification with EDX has also been carried out on Shorea uliginosa and Dyera costulata. The depth of penetration decreases with the incident angle from 0° until 50°. The surface diameter of penetration for Shorea uliginosa and plywood increases with the incident angle from 0° until 20°, after that it remained decreased until 50°, while the surface diameter of penetration for Dyera costulata remained increases from 0° until 50°. The degree of depth of penetration and surface diameter of penetration as a function of incident angles are Shorea uliginosa>plywood>Dyera costulata. The depth of penetration and surface diameter of penetrations for Shorea uliginosa, plywood and Dyera costulata decrease, as the power density increases. Shorea uliginosa has the highest depth of penetration as it has produced the smallest surface diameter of penetration while plywood has produced the depth and surface diameter between Shorea uliginosa and Dyera costulata. Dyera costulata has the lowest depth as it has produced the greatest surface diameter of penetration. The depth of penetration decreases with the distance of wood samples from laser source from 5 cm until 30 cm. The surface diameter of penetration increases with the distance of wood samples from laser source from 5 cm until 30 cm. Melting was observed for all components of the wood structure and the breaking of molecular bonds by direct interaction with a photon seems to be the dominating process. The EDX result shows that irradiation reduced the percentage of the elements in wood samples. The analysis will assist the manufacturing industry to choose a suitable laser system for cutting woods. Several chemical processes contribute to the effect of the far infra red laser radiation especially the amount of absorbed energy.
Effect of Temperature on DC Conductivity of CdSe
Amalina N. M , Z. A. Talib , W. M. D. W. Yusoff, Josephine L. Y. C. ,
Norfazlinayati O., Emma Z.M.T
Department of Physics, Faculty of Science, University Putra Malaysia,
43400 UPM Serdang, Selangor Darul Ehsan, Malaysia
In recent years, much attention has been paid to semiconducting II-VI compounds because of their optoelectronic properties and application. Among the II-VI semiconductors, Cadmium Selenide, CdSe has been emerged as potential AIIBVI type candidate in optoelectronic device applications such as fabrication of a photoelectrochemical (PEC) cells, non-linear optics, gas sensors, photoconductors, thin film transistors, gamma ray detectors, large-screen liquid crystal display, photoluminescence response, solar cells and etc. In this paper, effect of temperature on dc conductivity of CdSe is discussed. The measurements were carried out on bulk samples of CdSe of uniform disc. Sandwich method was used to determine the dc conductivity of CdSe in temperature range 200K – 500K. From the experiment, the conductivity increase from 6.06x10-12 S/cm at 200K to 2.73x10-5 S/cm at 500K. So, CdSe sample showed a semiconducting nature; electrical conductivity increases with increasing temperature.
Theoretical Analysis of Left-Handed Metamaterials using Adomian Decomposition Method
Mohd Rafie Johan
Department of Mechanical Engineering, University of Malaya
50603 Kuala Lumpur, Malaysia
In this presentation we review of the current state of the physical properties of the left-handed metamaterials together with analytical results. This kind of materials has been studied recently due to some non-intuitive and strange behavior. Using Adomian Decomposition Method, we were able to solve analytically nonlinear electromagnetic wave equation in left-handed metamaterials.
Materials with simultaneously negative dielectric permittivity and magnetic permeability in a certain frequency range demonstrate many interesting and unusual physical properties  and are believed to have strong application potential . Some of the properties, such as negative refraction, were experimentally confirmed . Several recent studies showed that the nonlinear wave interaction in left-handed materials has peculiar features [4-5].
In this paper we study coupled nonlinear Schrodinger equations for electromagnetic wave propagation in nonlinear left-handed materials. For isotropic and homogeneous nonlinear left-handed materials, the Maxwell’s equation for electric and magnetic fields lead naturally, within the slowly varying approximation to a system of coupled nonlinear Schrodinger equations. The equations are:
Eqs.(1) & (2) were solved analytically using Adomian Decomposition Method .
We found that Adomian Decomposition Method allowed much accurate and more efficient solution compared to other method like finite element, …etc.
 V. G. Veselago, Sov. Phys. Usp. 10, 509 (1968).
 Optics Express, sepecial issue on Negative Refraction and Metamaterials, 11, 639-755 (2003).
 D. R. Smith & N. Kroll, Phys. Rev. Lett. 85, 2933 (2000).
 I. V. Shadrivov et al., Phys. Rev. E 69, 016617 (2004)
 V. M. Agranovich et al., Phys. Rev. B 69,165112 (2004)
 G. Adomian, J. Math. Anal. App. 135 (1988) 501-544.
On The Expression of Exoticity of A Slowly Rotating Wormhole
Anuar Alias, Ithnin Abdul Jalil and Hasan Abu Kassim
Department of Physics, University of Malaya, 50603 Kuala Lumpur, Malaysia
For a wormhole to be traversable it is necessary to investigate the effect of a slowly rotating wormhole on the exoticity of the exotic matter. From the null energy condition we can derive the expression of exoticity and with the inclusion of the rotating effect we can determine whether it is of any benefit to reduce the exoticity and thus reduce the requirement of the exotic matter. Having derived the exoticity expression, we can specifically check the exoticity at the throat and find the relationship between the flaring out characteristic of the wormhole and the exoticity.
A Study of One Space Dimension Generalised Order Partial Differential Equations of the Parabolic Type
Ithnin Abdul Jalil1 and Rio Hirowati Shariffudin2
1Department of Physics,Faculty of Science, University of Malaya,
2Institute of Mathematical Sciences ,Faculty of Science, University of Malaya,
50603 Kuala Lumpur, Malaysia
The one space dimension generalized order parabolic equation is given by the equation
over a finite interval and with xL < x < xH and t > 0 with 1< a < 2. The space fractional equation above is approximated by a Riemann fractional derivative. The shifted Grünwald approximation procedure is used at all time levels. Using the Crank-Nicolson method which is implicit in nature, the resulting matrix is lower triangular with non-zero elements on the super diagonal. Our work emphasizes on using even number of simulation points because we observe that on using an even number of interior points we are able to simulate two unknowns at any one time in a Gauss-Seidel methodology. This method is chosen because of the ease in dealing with inverses of 2x2 matrices. From the study we will be able to understand the stability and convergence of the iterative procedure.
Core Calculation of 1 MW Reactor Triga Puspati (RTP) Using Continuous Energy Method of Monte Carlo MVP Code System
Julia Abdul Karim and Adnan Bokhari
Reactor Facility Unit, Malaysian Nuclear Agency (Nuclear Malaysia)
43000 Kajang,Selangor, Malaysia
The RTP is a light-water moderated from TRIGA MARK II type with having power capacity of 1MWatt. It is built in 1979 and attained the first criticality on 28 June 1982. The RTP was designed mainly for neutron activation analysis, small angle neutron scattering, neutron radiography, radioisotope production, education and training purposes. It uses standard TRIGA fuel developed by General Atomic in which the zirconium hydride moderator is homogenously combined with enriched uranium. It has cylindrical core but not in periodically in its lattice structure, which possibly locates 127 of fuel elements. Both of the coolant and moderator uses light water system and the reflector was made from high purity graphite. Because of this research reactor’s power is relatively small compared to the power reactor; it uses natural convection for its cooling system. To ensure the integrity of the core, fuel shuffling have been made for several times. Until now, there are 11 configurations of the core and recently has achieved the 12th configuration. This paper will described the RTP core calculation using Monte Carlo MVP code system. MVP is a general multi-purpose Monte Carlo codes for neutron and photon transport calculation based on the continuous energy and multi-group methods. In MVP, RTP core has been modeled using cylinder along the z-coordinate geometry and its cross section data has been calculated beforehand. The objectives of the calculation are to calculate the multiplication factor values (keff), fission density and flux distribution from the tally data.
DC Conductivity Studies in Conducting PPy Polymer with Applied Temperature
Norfazlinayati O.1, Z. A. Talib1, A. Kassim2, Josephine L.Y.C.1, and A. H Shaari1
Department of Physics1, Department of Chemistry2,
Faculty of Science, Universiti Putra Malaysia,
43400 UPM Serdang, Selangor
Conductive polymers have generated a great deal of interest towards the applications to produce simple and faster devices. Polypyrrole (PPy) conducting polymer is the most extensively studied polymer due to the high conductivity and optimal mechanical properties. In this paper, the PPy conducting polymer was prepared by chemical reaction method using Iron (III) Chloride 6-hydrate (FeCl3.6H2O) as a dopant. The effected of temperature on the surface dc conductivity for various mole ratio of FeCl3/PPy was measure by using four probe method. The voltage was increased with increasing current for all of measurements in the value range between 10 mA and 50 mA from room temperature to 380K. This result also indicated that conductivity increased as temperature increased. However, after the maximum temperature, 340K the conductivity decreased with increasing temperature. It is observed that both concentration of the dopant and temperature influenced the conductivity value for PPy conducting polymer. The activation energy for this polymer is also examined.
The Synthesis, Characterization and DC Electrical Conductivity of Poly[Di(2,5-Dimercapto-1,3,4-Thiadiazole)-Metal] Complexes
Ali G. El-Shekeil , Hussein M. Al-Maydama and Omar M. Al-Shuja'a
Department of Chemistry, Faculty of Science, Sana’a University, Yemen.
P. O. Box 12463, Sana’a, Yemen
Poly[di(2,5-dimercapto-1,3,4-thiadiazole)]-metal complexes of Co(II), Ni(II), Cu(II) and Zn(II) were synthesized by the reaction of 2,5-dimercapto-1,3,4-thiadiazole (6.6 mmol) with anhydrous cobalt, nickel, copper and zinc chlorides (3.3 mmol) in absolute ethanol under reflux for 24 hours. The products were characterized by elemental analyses, electronic spectra, FTIR spectroscopy, as well as thermal analyses (TGA and DTA) and X-Ray diffraction. The DC electrical conductivity variation of the poly[di(2,5-dimercapto-1,3,4-thiadiazole)-metal] complexes were studied in the temperature range 300-500 K as annealed for 24 hours at 100 ºC and after doping with 5% I2 for comparison. An attempt is made to interpret the DC electrical conductivity behavior and thermal properties to doping, annealing, structure and metal used.
Inductively Coupled Plasma Reactive Ion Etching on GaN in Cl2 Containing Plasmas
Siti Azlina Rosli and Azlan Abdul Aziz
1Nano Optoelectronics Research and Technology Laboratory (N.O.R)
School of Physics, Universiti Sains Malaysia, 11800 Minden, Pulau Pinang, Malaysia
In this study, the plasma characteristics and GaN etch properties of inductively coupled Cl2/Ar plasmas were investigated. It has shown that the results of a study of inductively coupled plasma (ICP) etching of gallium nitride by using Cl2/Ar is possible to meet the requirement (anisotropy, high etch rate and high selectivity, simultaneously. We have investigated the etching rate dependency on the percentage of Argon in the gas mixture, the total pressure and DC voltage. We found that using a gas mixture with 40% of Ar, the optimum rate of GaN was achieved. The etch rate were found to increase with voltage, attaining a maximum rate at -487V. The addition of an inert gas, Ar is found to barely affect the etch rate. Surface morphology of the etched samples was checked by scanning electron microscopy and atomic force microscopy. It was found that the etched surface was anisotropic and the smoothness of the etched surface is comparable to that of polished wafer.