Penentuan sifat kenyal bahan melalui teknologi ultrasonik / K. Azman, H.A.A. Sidek, H. Azhan, and S.Y.S. Yusainee

Kertas ini melaporkan secara umum tentang sejarah perkembangan ultrasonik. Bermula dari sejarah awal penemuan hinggalah kepada perkembangan terkini teknologi ultrasonik. Ciri-ciri mekanikal bagi gelombang ultrasonik dan hubungannya dengan teori kekenyalan serta penggunaannya turut diberikan untuk menentukan sifat kenyal bagi suatu bahan

Keberkesanan ujian tanpa musnah terhadap sifat kenyal papan tartal berorientasi (OSB) menggunakan perambatan gelombang ultrasonic / Azman K … [et al.]

Industri berasaskan kayu seperti papan tartal berorientasi (OSB) telah berkembang dengan pesatnya di Malaysia sebagai salah satu penyumbang kepada pertumbuhan ekonomi negara. Melalui kajian, bahan-bahan seperti papan tartal berorientasi merupakan alternative terbaik bagi menggantikan penggunaan kayu-kayu keras disebabkan oleh beberapa faktor antaranya ia mudah untuk dihasilkan, ringan, utuh serta murah kos penghasilannya. Dengan melihat kelebihan yang ada pada papan tartal berorientasi satu kajian telah dilakukan untuk menentukan sifat fizikal bahan ini secara saintifik. Maka, satu kajian telah dibuat terhadap papan tartal berorientasi (OSB) dalam menentukan sifat kekenyalannya secara ujian tanpa musnah (NDT) menggunakan teknologi perambatan gelombang ultrasonik. Sampel-sampel OSB telah disediakan oleh Unit Teknologi Perkayuan, manakala ujian teknologi ultrasonik di jalankan dengan kerjasama Jabatan Fizik, UPM. Sifat kenyal bahan dapat ditentukan dengan menggunakan alat pengukuran ultrasonik BP5 pada suhu bilik berasaskan kepada masa transit perambatan gelombang yang seterusnya memberikan maklumat tentang modulus kekenyalan. Daripada data modulus kekenyalan, keutuhan dan kekuatan bahan ini akan dapat dianggarkan secara makroskopik

Influence of chemical composition on the elastic properties of phosphate glass / Azman, K. … [et al.]

This paper will report the influence of the chemical composition that affected the mechanical properties of phosphate glass. In this study lead oxide (PbO) has been used as the chemical reagent and the elastic property was evaluated by using the ultrasonic measurement technique. A series of phosphate-based glass with the percentages of lead oxide varies from 10% to 60% were prepared. An ordinary melt-quench technique of preparation produced high quality of lead phosphate glasses (PbO-P2O5). The ultrasonic measurement was carried out for the glass series at room temperature by using the Matec MBS 8000 Instruments. From the velocities of the ultrasonic waves namely longitudinal, VL and shear, Vs waves the data has been used to estimate the elastic modulus such as bulk modulus. Young's modulus, Poisson ratio etc. for each composition

Risk Quantification in Coal Procurement for Power Generation: The Development of Supply Shortage Impact Matrix

Systems are secure if its have lower risks of system interruption. However, to determine the optimum level of security is an area where requires more research. In principle, the optimum level of security that a system provides is determined by the interaction between the cost of providing extra security and the value to consumers. The risks in energy system have to be quantified in order to identify the level of security. To make comparison between the cost of providing energy security and level of security, the quantified risks have to be in the same common variable as the costs. Then, an optimum level of security and cost can be estimated using appropriate methods. As no such attempts have been tried to compare the risks and the cost in the same platform, it is difficult to determine the optimum security point between the risks and cost of providing that security. The objective of this paper is to present the development of Supply Shortage Impact for risk quantification in coal procurements for power generation. This method in combination with Non-delivery Probability Table will provide risk in common variable as the cost for presenting valuable information on security and cost of providing i

High remanance of strontium hexaferrite from millscale derived / N. M. Saiden … [et al.]

Strontium hexaferrite was prepared by using millscale as raw materials. Millscale is an impure iron oxide. The mil/scale was milled to obtain < 20um size powder particle in diameter and the oxide powder was separated into magnetic and non-magnetic particle in a I tesla external field. Magnetic particles such as magnetite (Fe3O4) were separate and wuestite (FeO) was oxidised into hematite (Fe2O3) at 500°C for 10 hours in air. The conventional sintering method was used for preparing green powder of strontium ferrite with composition SrO.6Fe2O3 r This process was done by utilising dry method in the mixing of Fe2O3 and SrCO3. The final sample was in pallet shape with 10.84 mm diameter width and 11.39mm tickness. The sample was magnetized, followed by measurement of remanance, coercive force and (BH) of strontium ferrite permanent magnet. Resistivity, curie temperature and density of sample were also measured. The results showed that mill scale has the potential to be a raw material for a high quality permanent magnet material in the future

Preparation and characterization of surface magneto-optic kerr effect (smoke) in strontium ferrite (SrFe12O19) via sol-gel route / N. Yahya … [et al.]

Surface Magneto-Optic Kerr Effect (SMOKE) measurements performed on polycrystalline SrFe12019 ferrites was obtained using an applied field of = 0.4 Tesla and at a temperature of 300 K temperature. In this project, strontium hexaferrites were prepared by the chemical sol-gel route to get fine, pure and homogeneous of powders. Ferum Nitrate Hexahidrate, Fe(NO3) 3- 6H20 and Strontium Nitrate, Sr(NO2)3 were dissolved in citric acid solution by using a magnetic stirrer. The solution was slowly evaporated until a gel was formed after 2 weeks. This gel was dried at 110 °C in an oven for 2 days. The powders were analyzed by using X-ray Diffraction at various temperatures (800 °C, 900 °C and 1000 °C) to confirm the formation of the strontium ferrite phase. These powders were then presintered at 800 °C for 3 hours. After that, the powders were sieved and were mixed with PVA liquid as a binding agent before being moulded into pellet shape. The samples were sintered at 950 °C and 1000 °C for 3 hours in air. From the results, it was found that the formation of SrFe12O19 phase occurs at 1000 °C. In conclusion, the both SrFe12O19 (sintered at 950 °C and 1000 °C) showed Kerr rotation, ΨKerr about 1.1° and 1.5°, respectively

Magnetic characterisation using approximation method (APM) of BaFe12 0 19 derived from millscale / R. S. Azis … [et al.]

This paper describes a new method for measuring the magnetic properties of hexagonal Barium ferrite using approximation method (APM) theory. The sample was prepared by recycling the waste steel product from Malaysian steel factories. Using a Curie temperature separation technique, the wustite, FeO contained in the millscale was separated by this new technique using de-ionized water at 90°CI 100°C in the presence of IT external field. The wustite was then oxidized in the air at 400°C/500°C/600°C for 10 hours. An XRD phase analysis showed that a very high percentage of Fe20 3 was present in the final powder preparation. A conventional processing method was then done to prepare hexagonal BaFe'20'9 pallet shaped samples. Analysis of samples was done on grain size, saturation magnetization, coercive force and remanence. The magnetic properties were measured using approximation method (APM) theory. The high remanence 20000e, 20000e saturation magnetisation and 15000e coercive force of sample derived from millscale shows that this technique used has a high percentage for magnetic properties measurement in the future

Dynamic magnetic properties of mn doped YBa2Cu3O7_δ superconducting ceramics / S. A. Halim … [et al.]

AC complex susceptibility, X = X' + i X", measurements were done on the YBa2Cu3O7_δ superconducting samples doped with Mn at Y, Ba and Cu sites Y123 with nominal starting composition (x = 0.02 and 0.1). The data of X' shows that the coupling of the grains in samples that doped at Cu site are weaker than that samples doped at Y and Ba sites as shown by using the Ambegaokar-Baratoff equation 10 = 1.57 x 108Tc2-/( Tc-Tej), the calculated values of Josephson current, 10 where 1o(in y > l0(in Ba) > 10(in Cu) due to the weakening of the grain's coupling. This observation is supported by the intrinsic coupling loss, Tp obtained from X" that shows a bigger shift of the intergranular coupling peak, Tp, towards lower temperature in Mn doping at Cu site as compared to the doping in Ba and Y sites. Hence the effect of doping is obvious at higher concentration for all samples. Analysis based on the sensitivity of the data of dx'/dT versus temperature furnished further information on the two step transition related to the coupling of the grains in all systems

Sustainable bio-economy that delivers the environment-food-energy-water nexus objectives: the current status in Malaysia

Biomass is a promising resource in Malaysia for energy, fuels, and high value-added products. However, regards to biomass value chains, the numerous restrictions and challenges related to the economic and environmental features must be considered. The major concerns regarding the enlargement of biomass plantation is that it requires large amounts of land and environmental resources such as water and soil that arises the danger of creating severe damages to the ecosystem (e.g. deforestation, water pollution, soil depletion etc.). Regarded concerns can be diminished when all aspects associated with palm biomass conversion and utilization linked with environment, food, energy and water (EFEW) nexus to meet the standard requirement and to consider the potential impact on the nexus as a whole. Therefore, it is crucial to understand the detail interactions between all the components in the nexus once intended to look for the best solution to exploit the great potential of biomass. This paper offers an overview regarding the present potential biomass availability for energy production, technology readiness, feasibility study on the techno-economic analyses of the biomass utilization and the impact of this nexus on value chains. The agro-biomass resources potential and land suitability for different crops has been overviewed using satellite imageries and the outcomes of the nexus interactions should be incorporated in developmental policies on biomass. The paper finally discussed an insight of digitization of the agriculture industry as future strategy to modernize agriculture in Malaysia. Hence, this paper provides holistic overview of biomass competitiveness for sustainable bio-economy in Malaysia

Luminescence spectra of TeO ₂-PbO-Li ₂O doped Nd ₂O ₃ glass

A tellurite glass of TeO 2-PbO-Li 2O doped with Nd 2O 3 has been successfully fabricated by using the conventional melt-quenched technique. The absorption and emission spectroscopy have been identified using UV-VIS-NIR and photoluminescence spectrometer, respectively. From the spectroscopy, ten significant spectra have been observed in the region of 400-900 nm. The absorption wavelength centered at 585 nm attributed to 4I 9/2 → 4G 5/2 transition is the predominant wavelength to be used as the excitation wavelength. Emission spectra have been determined by using 585 nm excitation wavelength at room temperature. From the emission spectra, seven distinctive upconversion bands contributed from Nd 3+ were observed in the region of 400-1500 nm. It was found that the bands were centered at 450 nm ( 4G 11/2 → 4I 9/2), 485 nm ( 4G 11/2 → 4I 11/2), 605 nm ( 4G 11/2 → 4I 15/2), 665 nm ( 4G 7/2 → 4I 13/2), 880 nm ( 4F 3/2 → 4I 9/2), 1062 nm ( 4F 3/2 → 4I 11/2) and 1340 nm ( 4F 3/2 → 4I 11/2), respectively. These emission bands showed the possibility of visible and near infrared emission spectra