118 research outputs found
Aziz Deraman Naib Canselor UMT
No full textProfesor Dr. Aziz Deraman dilantik sebagai Naib Canselor UMT bagi menggantikan Profesor Datuk Dr. Sulaiman Md. Yassin yang bersara
Influence of retrogression and re-aging heat treatment to stress corrosion cracking resistance on Al-Zn-Mg-Cu alloy / Deraman R., Aziz M. R. And Y. Yaakob
No full textThe Al-Zn-Mg-Cu alloy is classified as a high strength to weight ratio material and is widely used in the aerospace structures. This alloy is susceptible to severe localized corrosion induced by heat treatment. The objective of this
study is to elucidate alternative heat treatment techniques, which reduce the alloys susceptibility to Stress Corrosion Cracking (SCC). A series of different heat treatments have been performed in the Al-Zn-Mg-Cu alloy using cube shaped and C-ring specimens that had been T6- and T7-tempered and undergone Retrogression and Re-aging (RRA) heat treatments. The specimens were exposed to hardness testing, optical testing and immersion testing in a
corrosive environment. The effectiveness of the heat treatments was evaluated with respect to improvements in corrosion resistance and the longevity of the Al-Zn-Mg-Cu alloy. The susceptibility of the Al-Zn-Mg-Cu alloy to SCC has been directly related to the precipitation of MgZn2 particles at the grain boundaries. Precipitation hardening of Al-Zn-Mg-Cu alloy increases the hardness of the material, but increases susceptibility to SCC failure. RRA
treatment greatly improved the corrosion resistance and longevity of the alloy combined with minimal strength reduction
Structural and luminescence properties of borate glass with lithium and strontium modifier doped with transition metal ions
No full textA system of borate based glass with different modifier but similar dopant was investigated to determine both the structural and photoluminescence properties. The glass sample from the series of X(M):(1-X)B 2O 3 where 0.2 ≤: X ≤:0.7 mole% and M was Li 2O and SrO, and the metaborate composition of glass was doped withMn 2+, Fe 2+ and Zn 2+ ions. The effect of the modifier towards the structural and photoluminescence properties in the glass samples was investigated using Fourier-Transfer Infrared (FT-IR) spectroscopy and photoluminescence spectroscopy. Infrared spectrum revealed the traces of BO 3 and BO 4 units at different modifier and concentration. Significant changes in the host structure showed modification at specific region depending on the type of modifier. The photoluminescence of the samples were studied using the luminescence spectrophotometer. The samples were excited at different emission wavelength to compare the results. This study showed that with the introduce Mn 2+, Fe 2+ and Zn 2+ ions as activators within the host material enhanced photoluminescence characteristic
Bound of character sums associated with Beatty sequences
No full textThis study is on the bound problems of Beatty sequences. Beatty sequences appear
with special versatility in the arithmetic properties of sequences which is in the form
of [αᵣ] where α is an irrational and r is a natural number. This study consider nonhomogeneous
Beatty sequences in the set of Bα,Bα = {[αᵣ + β] : r = 1,2,3,...}
and concerns on solving distribution of bounds sequences with different conditions
of integer parts r.
The estimation of the double character sums can be obtained by identifying the
cardinality of double character sums. The identification of cardinality applies
properties of character sums associated with composite moduli. It consists of
multiplicative and additive character sums with representation of polar form in
double character sums extended to composite moduli. The character sums in this
form ∑X X(d1)X(d2) gives the result rely on φ(m)+1 if d1 is equal to d2 and for
the rest conditions will give zeroes. Thus the cardinality of double character sums
obtained is much less than φ(m)R#K where R is the highest integer terms in the
sequences under consideration.
Discrepancy of the sequences is used to estimate the bound due to the ability
of measuring the uniformity of the sequences. Then, by applying discrepancy,
Cauchy inequalities and the cardinality of the double character sums associated with
composite moduli, the estimation of Beatty sequences with different conditions of
integral parts r is obtained. This study provide six different conditions of integral
part r which are r is prime number associated with prime modulo, r is prime number
associated with composite moduli, r is Fibonacci number associated with composite
moduli, r is y-smooth number associated with prime modulo, r is y-smooth number associated with composite moduli and r is natural number associated with composite
moduli. In general, the result of bound problem under consideration is much less than (φ(m)) ¼ R+RDαβ (R).
As a conclusion the bounds of the character sums of Beatty sequences are depends
on the size of cardinality of double character sums
A Study on Blade Performance of Transverse Axis Wind Turbine Mounted on a Rooftop
No full textThe idea of generating electricity using rooftop mounted wind turbine has raise over the last decade. It is due to rising energy costs and the global need to reduce the use of carbon and greenhouse emissions. The rooftop mounted wind turbine has the potential to replace the source of generating the electric power. This research paper presents about the modeling, analysis and study of the blade design that affect performance of transverse axis wind turbine mounted on a rooftop. It consists of background of study of the project, problem statement, objectives, scope of study, literature review for the relevance, methodology and final result, conclusion and recommendations to improvise the experiment. In this project, the author design and fabricate the transverse axis wind turbine based on relevant parameters and determine which turbine offer the best in term of speed that can be generated from the wind. At the end of this research, several recommendations have been made to improve the project that had been don
Structural study of antimony borate glass system doped with transition metal ions using infrared and raman spectroscopy
No full textA series of Antimony Borate glass samples were investigated to determine the structural feature. The glass samples from the series of xSb 2O 3:(1-x)B 2O 3 with composition of 20≤:x≤:60 mol% and 0.6 Sb 2O 3:0.4B 2O 3:y with y is 0.01 mol% of Nb 2O 5, CuO, ZnO system have been prepared using melt-quenching technique. The structural properties of Sb 2O 3 host and the introduction of dopants onto the host sample has been investigated using Infrared and RAMAN Spectroscopy. The result of IR and Raman Spectroscopy revealed that the network structure of the studied glasses is mainly based on BO 3 and BO 4 units placed in different structural groups, the BO 3 units being dominant. IR spectra obtained shows conversion of BO 3 to BO 4 units upon the introduction of Sb 2O 3 commonly known as boron anomaly effect. The glass network can be modified with the presence of Sb 2O 3 and activator ions. The significant behavior in Raman Spectra indicates the presence of boroxol groups consisting of pure BO 3 groups and mixed BO 3-BO 4 structural units. This study shows that the vibrational spectroscopy (Infrared and Raman) provide useful method, and inter-complementary information about the structural properties of antimony modified borate glasses
Structural study of lithium strontium borophosphate crystal using x-ray diffraction and infrared spectroscopy
No full textIn order to study the influence of deionized water and heat treatment on the structure of the crystal, a compositional series of 20Li 2O:20SrO: 30B 2O 3:30P 2O 5 with deionized water and without de-ionized water as a solvent were prepared at 800°C for different sintering time from 7 to 24 h. The crystalline phase and structural of 20Li 2O:20SrO:30B 2O 3:A 30P2O5 crystal was studied using X-ray powder diffraction (XRD) and Infrared (IR) Spectroscopy. From the XRD result, samples prepared with deionized water as solvent displayed better crystalline respond. The samples showed a better crystalline structure when it was sintered for 24 h as compared to 7 h. The infrared spectra of the samples showed three distinctive regions around 1200 - 650 cm -1, 650 - 360 cm -1 and 360 cm -1 showing clear signs of boron units as the major host structure
Electrocatalytic Detection of Dopamine and Uric acid at poly (Basic Blue B) Modified Carbon Nanotube Paste Electrode
No full textElectropolymerization of Basic Blue B by cyclic voltammetry (CV) onto the carbon nanotube (CNT) paste electrode results in the formation ofpoly (Basic Blue B) film/modified CNT paste electrode (PBBB/MCNTPE). The Modified electrode was used for the electrochemical determinationof dopamine (DA) and uric acid. CV results showed that this PBBB/MCNTPE have reversible redox behavior in electrolyte solution. The resultingPBBB/MCNTPE were characterized using field emission scanning electron microscope. The analytical ability was tested with respect to the scan rate,number of cycle, pH of solution, and concentration variation. Measurement of these analytes studied simultaneously by CV and differential pulsevoltammetry methods. The analytical curve for DA presented linear dependence over the concentration range from 3 × 10 M witha linear correlation coefficient of 0.99036. The detection limit of this method was 5.8 × 10. The method has good selectivity and sensitivity withsatisfactory results.Keywords: Carbon nanotubes paste electrode, Cyclic voltammetry, Poly (Basic Blue B), Dopamine, Uric acid
Study of crystallization kinetics of Teo2-Na2O-Mgo glass using Ozawa method: influence of europium
No full textThe study of the crystallization kinetics of rare-earth doped glass stimulated much interest especially for crystallization process. In this work transparent Eu2O3 doped glasses with composition TeO2 - Na2O - MgO were prepared using conventional melt-quenching technique. The amorphous nature of glass was confirmed using X-ray diffraction method. The influence of Eu3+ content on the crystallization kinetics of the glass such as activation energy (E-a) was thoroughly evaluated under non-isothermal conditions using DTA. The crystallization kinetic at different heating rate from 5 degrees C min(-1) to 25 degrees C min(-1) at different crystallization temperature (T-p) were examined and verified using Ozawa method. The result showed that the activation energy (E-a) was decreased with the increasing of the dopant concentration from 319.8 eV to 93.5 eV
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