IIUM Engineering Journal
Not a member yet
783 research outputs found
Sort by
The reduction of stress concentration in a uni-axially loaded infinite width rectangular isotropic/orthotropic plate with central circular hole by coaxial auxiliary holes
Get PDFA comprehensive plane stress finite element study is made for reduction of stress concentration factor (SCF) in a uni-axially loaded infinite width rectangular isotropic/orthotropic plate with central circular hole. The finite element formulation was carried out by the analysis section of the package ANSYS. With the help of present work, stress concentration can be reduced up to 24.4 % in an isotropic and 31 % in an orthotropic plate by introducing four coaxial auxiliary holes on either side of main hole. The study reveals that the introduction of these holes helps to smooth flow of the tensile stress past the main hole and result a reduction in stress concentration factor. With such reduction in maximum stress levels, the improvement in fatigue life of a component can be significant
Feasibility Analysis Of Free Space Earth To Satellite Optical Link In Tropical Region
Get PDFFree Space Optics (FSO) becomes a great attention because of the chances in transmitting data up to 2.5Gbps. There are a lot of advantages offered by FSO such as easily deployment with saving time and cost and no electromagnetic interference. In spite of the advantages, FSO has an uncontrolled drawback which is highly sensitive to atmospheric phenomena because uses air as tranmission medium. Current studies and researches are only focusing on FSO terrestrial link with short path length and based on data from temperate region. Therefore, this paper is aiming to provide feasibility analysis of FSO link from earth to satellite especially Low Earth Orbit (LEO) based on atmospheric data in tropical region. The analysis will include the losses from geometrical attenuation, absorption, scintillation, haze attenuation, and rain attenuation. ABSTRAK: Ruang Bebas Optik (Free Space Optics (FSO)) mendapat perhatian kerana kebolehannya memancarkan data pada kelajuan tinggi. Di sebalik kelebihannya, FSO amat sensitif terhadap fenomena atmosfera kerana ia menggunakan udara sebagai perantara transmisi. Penyelidikan dan kajian terkini hanya memfokus kepada jalinan darat FSO dengan kepanjangan jarak pendek dan bergantung kepada kawasan tenang. Oleh itu, kertas ini menyasarkan untuk memberikan analisis kebolehlaksanaan jalinan FSO dari bumi ke satelit terutamanya Orbit Rendah Bumi (Low Earth Orbit (LEO)) bergantung kepada data atmosfera di kawasan tropika. Analisa termasuklah kehilangannya akibat pengecilan geometri, penyerapan, kelipan, pelemahan jerebu dan pelemahan hujan.KEYWORDS: feasibility; Free Space Optics; availability; atmospheric attenuation; beam divergence angle; elevation angl
Observation On Void Formed In Oxide Scale Of Fe-Cr-Ni Alloy At 1073k In Dry And Humid Environments
Get PDFVoid formation in oxide scale during high temperature oxidation is a common phenomenon. Over a long period of time voids will affect the mechanical property of scales by influencing the cracking and spalling. Voids formed in dry environment are different than that of formed in humid environment. With the presence of water vapor in humid environment the formation of void will increase, thus greater number of void compared to that in dry environment. Fe-Cr-Ni alloy samples were exposed isothermally at 1073 K in air (P_(O_2 )= 0.21atm = 2.1×?10?^(5 )Pa) and humid (air + steam) environments. XRD analysis done to all samples confirms that Fe2O3, Fe3O4, NiCr2O4, FeCr2O4, Cr2O3 and NiO phases exist in the scale. EDX analysis done shows varying compositions of Fe,Cr,Ni and O in outer and inner oxide scale, oxide scale/metal interface and metal. Field emission scanning electron microscope (FE-SEM) was used to investigate voids formed in the cross sections of the oxidized samples. Volume fraction of voids in the oxide scale was calculated in accordance to the cross sectional area fraction of voids in the scale. It shows that Fe-Cr-Ni alloy samples exposed in humid environment has as high as 71% more voids than that exposed in dry environment. It is concluded that the humid environment increased the number of void formed in the oxide scale, thus facilitates the exfoliation of protective scale during the high temperature oxidation. ABSTRAK: Pembentukan gelembung udara di dalam lapisan oksida ketika proses pengoksidaan di suhu tinggi merupakan satu fenomena biasa. Pada satu jangka masa yang panjang gelembung-gelembung ini akan memberi kesan kepada sifat mekanikal oksida dengan mempengaruhi pembentukan keretakan dan pengelupasan oksida. Gelembung udara yang terbentuk di dalam persekitaran kering berbeza daripada yang terbentuk di dalam persekitaran lembap. Dengan adanya wap air, pembentukan gelembung akan bertambah berbanding yang terbentuk di dalam persekitaran kering. Sampel aloi Fe-Cr-Ni telah dioksidakan secara isoterma pada suhu 1073 K di dalam udara (P_(O_2 )= 0.21atm = 2.1×?10?^(5 )Pa) dan lembap (udara + wap air). Analisis Pembelauan Sinar – X (XRD) kepada semua sampel menunjukkan oksida yang terbentuk ialah Fe2O3, Fe3O4, NiCr2O4, FeCr2O4, Cr2O3 dan NiO. Analisis Penyebaran Tenaga Sinar – X (EDX) menunjukkan komposisi Fe, Cr, Ni dan O yang berubah - ubah di lapisan oksida luar dan dalam, oksida/ antara muka logam dan logam. Mikroskop Imbasan Elektron-Pancaran Medan (FE-SEM) digunakan untuk meneliti gelembung di dalam oksida pada keratan rentas sampel. Pecahan isi padu gelembung yang terbentuk pada oksida dikira dengan merujuk kepada pecahan luas keratan rentas pada oksida tersebut. Sampel aloi Fe-Cr-Ni yang dioksidakan di dalam persekitaran lembap mempunyai kandungan gelembung udara 71% lebih banyak berbanding dengan yang dioksidakan di dalam persekitaran kering. Kesimpulannya persekitaran lembap meningkatkan bilangan gelembung yang terbentuk di dalam lapisan oksida, sekaligus memudahkan pengelupasan oksida semasa pengoksidaan suhu tinggi.KEYWORDS: high temperature oxidatio;, Fe-Cr-Ni alloy; void formation; quantitative analysis of voi;, dry environment; humid environmen
Automated Characterization of Single-Photon Avalanche Photodiode
Get PDFWe report an automated characterization of a single-photon detector based on commercial silicon avalanche photodiode (PerkinElmer C30902SH). The photodiode is characterized by I-V curves at different illumination levels (darkness, 10 pW and 10 µW), dark count rate and photon detection efficiency at different bias voltages. The automated characterization routine is implemented in C++ running on a Linux computer. ABSTRAK: Kami melaporkan pencirian pengesan foton tunggal secara automatik berdasarkan kepada diod foto runtuhan silikon (silicon avalanche photodiode) (PerkinElmer C30902SH) komersial. Pencirian diod foto adalah berdasarkan kepada plot arus-voltan (I-V) pada tahap pencahayaan yang berbeza (kelam - tanpa cahaya, 10pW, dan 10µW), kadar bacaan latar belakang, kecekapan pengesanan foton pada voltan picuan yang berbeza. Pengaturcaraan C++ digunakan di dalam rutin pencirian automatik melalui komputer dengan sistem pengendalian LINUX.KEYWORDS: avalanche photodiode (APD); single photon detector; photon counting; experiment automatio
Muslim Views On Organ Transplant
Get PDFIn Islamic worldview human cadaver is considered holy and sacred as of the living person. The human dignity bestowed on all mankind applies and it is extended to the corpse. For this reason, in the Muslim world at least, organ transplant has been contentious process. This paper is a study on the procedures and ethical implications of organ transplant. It evaluates the Islamic views on the issue. ABSTRAK: Pada panndangan Islam, mayat manusia adalah suci dan mulia sebagaimana orang yang masih hidup. Atas sebab ini, pemindahan organ dalam dunia Islam memerlukan proses yang teliti. Kertas ini mengkaji prosedur dan implikasi etika pemindahan organ dari sudut pandangan Islam.KEYWORDS: organ transplant; ethics; religion;Muslim view
Application of Artificial Bee Colony Algorithm and Finite Element Analysis for Optimum Design of Brushless Permanent Magnet Motor
Get PDFABSTRACT: This paper develops a mathematical relationship for the purpose of designing and selecting the optimum dimensions of a brushless permanent magnet motor. The design is optimised by the use of artificial bee colony algorithm with the goal of maximizing the power density and efficiency of the motor. The required dimensions of the brushless motor are calculated based on the optimum power density and efficiency requirements. Finally, the predicted results of the optimisation are validated using a 2-D numerical program based on finite element analysis.ABSTRAK: Kajian ini mencadangkan persamaan yang menghubungkan rekabentuk dan dimensi magnet motor kekal tanpa berus. Rekabentuk optima berdasarkan algorisma koloni lebah tiruan dengan tujuan meningkatkan ketumpatan kuasa dan keberkesanan dibentangkan dalam kajian ini. Dimensi magnet motor kekal tanpa berus dihitung dengan ketumpatan kuasa optima dan keberkesanan. Akhirnya, keputusan telah disahkan dengan menggunakan program berangka 2-D berdasarkan analisis elemen finit.KEYWORDS: brushless; permanent magnet motor; power density; artificial bee colony; algorithm; finite element analysi
PROCESS MODELLING AND DEBOTTLENECKING STUDY OF A VACCINE PRODUCTION
Get PDFABSTRACT: The main objective of this research work was to model and optimise the production of a locally-developed Infectious Coryza (IC) vaccine. The simulation work was performed using a commercially available batch process simulator SuperPro Designer v5.5. Six debottlenecking schemes were analysed using throughput analysis and cost to benefit ratio (CBR) when the annual production was set to increase by 100%. Based on the economic analysis, the selected debottlenecking scheme has an annual predicted revenue of USD 240 million, with a gross margin of 9.13% and a return on investment (ROI) of 46.12%. In addition, the payback period of the selected scheme is estimated to be within three years. ABSTRAK: Objektif utama dalam penyelidikan ini adalah untuk memodelkan dan mengoptimumkan hasil pembuatan vaksin tempatan Coryza berjangkit. Kerja simulasi ini dijalankan menggunakan alat simulasi Super Pro Designer v5.5. Sebanyak enam (6) skema khusus diujikaji menggunakan analisis pemprosesan dan kos kepada nisbah faedah (CBR) apabila pembuatan tahunan meningkat kepada 100%. Berdasarkan analisis ekonomi yang telah dilakukan, sesuatu skema khusus yang dipilih mempunyai keuntungan sebanyak USD 240 juta dengan margin kasar 9.13% dan pulangan atas pelaburan (ROI) sebanyak 46.12%. Selain itu juga, tempoh pembayaran balik bagi skema yang dipilih dianggarkan dalam tempoh tiga(3) tahun.KEYWORDS: process simulation; modelling; debottlenecking; optimisatio
Computer Aided Design and Analysis of a 2-4 GHz Broadband Balanced Microstrip Amplifier
Get PDFIn this paper, a computer-aided design and analysis of a 2-4 GHz broadband balanced microstrip amplifier using a full computer simulation program developed by the author and others is presented. A short and efficient CAD procedure for broadband amplifier design is introduced. The first step is to design an initial narrow-band high gain microstrip amplifier at 3-GHz central frequency. The second step is to optimize the initial lengths and widths of the input and output microstrip-matching circuits to get the broadband amplifier over the range 2-4 GHz. The analysis of both narrow and broadband amplifiers is investigated. In addition, with the design and analysis of a low-pass microstrip filter, the paper introduces the design and analysis of a Lange coupler. The final AC schematic diagram of the designed amplifier with the lengths and widths of microstrip lines is presented.Key Words: Computer-Aided Design and Analysis, Microstrip Amplifier, Microwave Amplifier
Stress Analysis of Polarization Maintaining Optical Fibers by the Finite Element Method
Get PDFStress-induced birefringence in single mode polarization maintaining optical fibers has been investigated using the finite element method. The modal birefringence caused by external forces in the Panda and the Side Tunnel fibers are calculated. It is found that the modal birefringence is directly proportional to the radial distance from the fiber center. As expected, the modal birefringence vanishes with the variation in the magnitude of the applied external loads.Key Words: Birefringence, Polarization, Panda Fiber, Side-Pit Fiber, Finite Element Method
Enhanced Coagulation Efficiency of Moringa Oleifera Seeds Through Selective Oil Extraction
Get PDFIn this laboratory based study, varying quantities of oil, corresponding to 20 % w/w, 25 % w/w and 30 % w/w kernel weight extracted from Moringa oleifera seeds ( S1, S2, S3) respectively were applied in the coagulation of model turbid water (kaolin suspension) and turbid river water samples from River Batang Kali and River Selangor in Malaysia to determine the percentage oil removed which gave the best coagulation efficiency. For model turbid water (kaolin suspension) coagulation of low turbidity of 35 NTU, medium turbidity of 100 NTU and high turbidity of 300 NTU, sample S2 gave the best turbidity removal corresponding to 91.7%, 95.5% and 99% respectively. Application of sample S2 to River Batang Kali with low initial turbidity of 32 NTU and high initial turbidity of 502 NTU gave a highest turbidity removal of 69% and 99% respectively. Application to River Selangor with medium initial turbidity- of 87 NTU and high initial turbidity of 466 NTU gave a highest residual turbidity' of 94% and 98.9%, respectively.Key words: Moringa oleifera seed, selective oil extraction, coagulation, model turbid water (kaolin suspension), river water, turbidity removal