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MATHEMATICAL MODELLING AND PERFORMANCE ANALYSIS OF DIFFERENT SOLAR AIR COLLECTORS
Get PDFThe purpose of using solar air collectors is to raise the atmospheric air temperature to a temperature which can be used for various low and medium temperature applications. Collector, absorber and airflow arrangement are the most important components in the solar air collector. The performance of the collector depends on its heat loss and the absorber area that is in contact with the airflow. This study involves the theoretical simulation of the effect of mass flow rate on the performance, for flat plate and v-groove collectors that are in single and double pass configurations. Results show that the v-groove double pass air collector has the highest efficiency value of 56% at . The performance is greater than flat plate double pass collector, which has an efficiency of 54% under the same operating conditions. KEYWORDS: solar air collector; flat plate collector (fpc); v-groove collector; efficiency; single pass; double pas
STUDIES ON THE EFFECT OF ARTIFICIAL AGEING HARDNESS ON TENSILE PROPERTIES AND IMPACT STRENGTH OF AL-6SI-0.5MG-2NI ALLOY
Get PDFThe effect of different scheduled artificial ageing hardness on the tensile and impact properties of Al-6Si-0.5Mg-2Ni alloy was studied. The solution treated Al-6Si-0.5Mg-2Ni alloy was aged isochronally for 1 hour at temperatures up to 300oC. The precipitation stages during ageing were monitored by hardness measurements. Tensile and impact properties were determined by standard tests. During artificial ageing, the yield and ultimate tensile strength were found to increase with ageing hardness; the maximum being attained at peak hardness. Ductility and impact toughness of the alloy, on the other hand decreased with ageing hardness, reaching the minimum at the highest hardness. The strength of Al- 6Si-0.5Mg-2Ni alloy was best at highest hardness but exhibits poor ductility and impact strength. KEYWORDS: Al-6Si-0.5Mg-2Ni alloy; ageing; hardness; tensile properties; impact strength
EXISTENCE OF SOLUTIONS OF FRACTIONAL INTEGRODIFFERENTIAL SYSTEM WITH NONLOCAL CONDITIONS
Get PDFABSTRACT :Â In the present paper we prove the existence and uniqueness of local solutions of a nonlocal Cauchy problem for a class of fractional integrodifferential equation. The results are obtained by using the theory of resolvent operators, the fractional powers of operators, fixed point techniques and the Gelfand-Shilov principle
NANO-BATTERY TECHNOLOGY FOR EV-HEV PANEL: A PIONEERING STUDY
Get PDFGlobal trends toward CO2 reduction and resource efficiency have significantly increased the importance of lightweight materials for automobile original equipment manufacturers (OEM). CO2 reduction is a fundamental driver for a more lightweight automobile. The introduction of Electrical Vehicles (EVs) is one initiative towards this end. However EVs are currently facing several weaknesses: limited driving range, battery pack heaviness, lack of safety and thermal control, high cost, and overall limited efficiency. This study presents a panel-style nano-battery technology built into an EV with CuO filler solid polymer electrolyte (SPE) sandwiched by carbon fiber (CF) and lithium (Li) plate. In addition to this, an aluminum laminated polypropylene film is used as the electromagnetic compatibility (EMC) shield. The proposed battery body panel of the EV would reduce the car weight by about 20%, with a charge and discharge capacity of 1.5 kWh (10% of car total power requirement), and provide the heat insulation for the car which would save about 10% power consumption of the air conditioning system. Therefore, the EV would be benefited by 30% in terms of energy reduction by using the proposed body. Furthermore, the proposed body is considered environmental-friendly since it is recyclable for use in a new product. However, the main limiting factors of the SPE are its thermal behavior and moderate ionic conductivity at low temperatures. The SPE temperature is maintained by controlling the battery panel charging/discharge rate. It is expected that the proposed panel-style nano-battery use in an EV would save up to 6.00 kWh in battery energy, equivalent to 2.81 liters of petrol and prevent 3.081 kg of CO2 emission for a travel distance of 100 km. KEYWORDS: epoxy resin; carbon fiber; lithium thin plate; energy generation; solid electrolyte batter
SILICON COMPATIBLE ACOUSTIC WAVE RESONATORS: DESIGN, FABRICATION AND PERFORMANCE
Get PDFABSTRACT: Continuous advancement in wireless technology and silicon microfabrication has fueled exciting growth in wireless products. The bulky size of discrete vibrating mechanical devices such as quartz crystals and surface acoustic wave resonators impedes the ultimate miniaturization of single-chip transceivers. Fabrication of acoustic wave resonators on silicon allows complete integration of a resonator with its accompanying circuitry. Integration leads to enhanced performance, better functionality with reduced cost at large volume production. This paper compiles the state-of-the-art technology of silicon compatible acoustic resonators, which can be integrated with interface circuitry. Typical acoustic wave resonators are surface acoustic wave (SAW) and bulk acoustic wave (BAW) resonators. Performance of the resonator is measured in terms of quality factor, resonance frequency and insertion loss. Selection of appropriate piezoelectric material is significant to ensure sufficient electromechanical coupling coefficient is produced to reduce the insertion loss. The insulating passive SiO2 layer acts as a low loss material and aims to increase the quality factor and temperature stability of the design. The integration technique also is influenced by the fabrication process and packaging. Packageless structure using AlN as the additional isolation layer is proposed to protect the SAW device from the environment for high reliability. Advancement in miniaturization technology of silicon compatible acoustic wave resonators to realize a single chip transceiver system is still needed. ABSTRAK: Kemajuan yang berterusan dalam teknologi tanpa wayar dan silikon telah menguatkan pertumbuhan yang menarik dalam produk tanpa wayar. Saiz yang besar bagi peralatan mekanikal bergetar seperti kristal kuarza menghalang pengecilan untuk merealisasikan peranti cip. Silikon serasi gelombang akustik resonator mempunyai potensi yang besar untuk menggantikan unsur-unsur diskret kerana keupayaan untuk mengintegrasikan dengan litar yang disertakan itu. Integrasi ini membawa kepada peningkatan prestasi, fungsi yang lebih baik dengan pengurangan kos pada pengeluaran jumlah yang besar. Oleh itu, Karya ini mengkaji silikon resonator akustik yang serasi, yang bersepadu dengan muka litar untuk membolehkan integrasi yang lengkap. Resonator gelombang akustik yang digunakan adalah gelombang permukaan akustik ( SAW ) dan gelombang akustik pukal ( BAW ) resonator . Kriteria penting untuk menilai prestasi resonator seperti faktor kualiti, frekuensi resonans dan kehilangan sisipan juga digariskan dalam setiap kerja sebelumnya. Pemilihan bahan piezoelektrik yang sesuai adalah penting untuk memastikan pekali gandingan elektromekanik yang mencukupi dihasilkan untuk mengurangkan kehilangan sisipan. Lapisan tambahan pasif SiO2  yang bertindak sebagai bahan rendah sisipan dipercayai meningkatkan faktor kualiti dan kestabilan suhu reka bentuk. Teknik integrasi juga dipengaruhi oleh proses fabrikasi dan pembungkusan. Struktur tanpa pembungkusan menggunakan AlN sebagai lapisan pengasingan tambahan itu dicadangkan untuk melindungi peranti SAW dari persekitaran untuk kebolehpercayaan yang tinggi. Banyak lagi kemajuan perlu dilakukan dalam pengecilan silikon serasi resonator gelombang akustik untuk merealisasikan sistem cip transceiver tunggal.KEYWORDS: RF-MEMS; piezoelectric; resonator; surface acoustic wave (SAW);bulk acoustic wave (BAW); FBA
ANALYSIS OF CHEMICAL COMPOUNDS OF AGARWOOD OIL FROM DIFFERENT SPECIES BY GAS CHROMATOGRAPHY MASS SPECTROMETRY (GCMS)
Get PDFABSTRACT: Agarwood oil is a highly prized type of oil due to its unique aroma. The oil is extracted from the fragrant resin found in the agarwood tree (trunk). The unique aroma and quality of agarwood resin and oil are contributed by the presence of certain chemical compounds. In this work, analysis and comparison of the chemical compounds of agarwood oil from A. malaccensis, A. sub-integra and a mixture of both were conducted. The essential oils were diluted in hexane (5%) prior to gas chromatography mass spectrometry (GCMS) analysis performed using Agilent GCMS 7890A coupled with MSD quadrupole detector 5975 C. Separation of analytes by gas chromatography was carried out using a Hewlett Packard HP-5MS silica capillary column (30 m X 0.25 mm X 0.25 mm). A total of 107 compounds were identified from the three samples of agarwood oils. Fifty-five (55) components were identified in A. malaccensis sample which contributes to the largest portion of the total compounds. About 20% of the compounds identified were aromatic and sesquiterpenes which have been revealed to be the main active compounds of agarwood oils which also give the aroma and pleasant odour of agarwood. Different compositions or profile of chemical components were found in agarwood oils from the two different species. Two compounds were commonly identified in all three samples namely 3-phenyl-2-butanone and alpha-cubebene. Further studies are needed to refine the results which later can be used to assist detection and authentication of agarwood as well as its scientific-based grading. ABSTRAK: Minyak gaharu merupakan sejenis minyak beraroma unik yang mendapat permintaan tinggi dan mahal. Minyak ini diekstrak daripada resin beraroma yang terbentuk di dalam batang pokok gaharu. Keunikan aroma dan kualiti resin dan minyak gaharu ini bergantung kepada kehadiran bahan kimia tertentu. Penyelidikan ini menjurus kepada analisis dan perbandingan bahan-bahan kimia yang terdapat dalam minyak gaharu daripada spesis A. malaccensis, A. sub-integra dan campuran kedua-duanya. Minyak gaharu dilarutkan di dalam 5% heksana sebelum dianalisis menggunakan kromatografi gas Agilent GCMS 7890A berserta spektormetri jisim (MSD quadrupole detector 5975 C). Kolum kapilari silika Hewlet Packard HP-5MS (30 m X 0.25 mm X 0.25 mm) digunakan untuk pemisahan bahan-bahan kimia tersebut. Sejumlah 107 kompaun dikenalpasti dalam ketiga-tiga sampel minyak gaharu tersebut dengan 55 kompaun didapati di dalam sample A. malaccensis. Ini merupakan bahagian terbesar daripada keseluruhan kompaun. Sebanyak 20 % daripada keseluruhan kompaun yang dikenalpasti adalah daripada kumpulan seskuiterpena dan bersifat aromatik, juga merupakan kumpulan yang bertanggungjawab memberi aroma yang unik kepada minyak gaharu. Setiap spesis didapati mempunyai komposisi atau profil bahan kimia yang tersendiri. Dua kompaun iaitu 3-phenyl-2-butanone dan alpha-cubebene ditemui dalam ketiga-tiga sample yang dianalisis. Kajian lanjut adalah perlu untuk memurnikan dapatan hasil penyelidikan yang berpotensi bagi membantu pengenalpastian gaharu berserta pembangunan penggredan gaharu yang lebih saintifik
COMPARISON OF TWO TOTAL RNA EXTRACTION PROTOCOLS FROM CHO-K1 CELLS FOR RT-PCR: CUT-OFF COST FOR RESEARCHERS
Get PDFABSTRACT: Various methods have been described to extract RNA from adherent mammalian cells. RNA isolation in conjunction with reverse transcription polymerase chain reaction (RT-PCR) is a valuable tool used to study gene expression profiling. This approach is now being used in mammalian cell bioprocessing to help understand and improve the system. The objective of this study was to compare and determine the most suitable RNA extraction method for CHO-K1 cells in a setting where a relatively large amount of samples was involved. Total RNA was extracted using Total RNA purification kit (without DNase treatment; Norgen, Canada) and RNeasy mini kit (with DNase treatment; Qiagen, USA) respectively. The extracted RNA was then reverse transcribed, and the cDNA was subjected to PCR-amplifying 18S. Yield from RNeasy kit was significantly higher (0.316 ± 0.033 µg/µl; p=0.004) than Total RNA purification kit (0.177 ± 0.0243 µg/µl). However, RNA purity for both methods was close to 2.0 and there was no significant difference between the methods. Total RNA purification kit is less expensive than RNeasy kit. Since there is no DNase treatment step in the former, extraction time for RNA is shorter. When the extracted RNA was subjected to RT-PCR, both methods were able to show detection of 18S at 219 bp.  Therefore, this study demonstrates that both protocols are suitable for RNA extraction for CHO-K1 cells. RNeasy mini kit (Qiagen) is recommended if higher yields is the primary concern and Total RNA Purification kit (Norgen) is recommended if time and cost are concerned. ABSTRAK: Pelbagai kaedah telah digunakan untuk mengekstrak RNA daripada sel mamalia lekat. Pemencilan RNA dengan menggunakan reaksi rantai polimerase transkripsi berbalik (RT-PCR) merupakan kaedah penting yang digunakan dalam mengkaji pernyataan gen berprofil. Pendekatan ini kini digunakan dalam pemprosesan bio sel mamalia untuk memahami dan menambah baik sistem. Tujuan kajian dijalankan adalah untuk menentukan dan membandingkan kaedah ekstraksi RNA yang paling sesuai bagi sel CHO-K1 di persekitaran di mana kadar sampel yang agak besar terlibat. Jumlah RNA diekstrak menggunakan kit penulenan Jumlah RNA (tanpa rawatan DNase; Norgen, Canada) dan kit mini RNeasy (dengan rawatan DNase; Qiagen, USA). RNA yang diekstrak kemudiannya diterbalikkan transkripsi, dan cDNA menjalani penguat PCR 18S. Hasil daripada kit RNeasy adalah lebih tinggi (0.316 ± 0.033 µg/µl; p=0.004) berbanding dengan kit penulenan Jumlah RNA (0.177 ± 0.0243 µg/µl). Walaupun begitu, kaedah penulenan RNA untuk kedua-duanya hampir 2.0 dan tidak terdapat perbezaan yang ketara antara keduanya. Kit penulenan Jumlah RNA adalah lebih murah berbanding dengan kit RNeasy. Memandangkan tidak ada langkah rawatan DNase dengan penggunaan kit Jumlah RNA, tempoh ekstrak RNA nya lebih pendek. Apabila RNA yang telah diekstrak menjalani RT-PCR, kedua-dua kaedah berjaya mengesan 18S pada 219 bp.  Kesimpulannya, kajian ini menunjukkan kedua-dua kaedah sesuai untuk mengekstrak RNA bagi sel CHO-K1. Kit mini RNeasy (Qiagen) lebih sesuai jika hasil yang tinggi diinginkan dan kit penulenan Jumlah RNA (Norgen) pula ideal, jika kos dan masa berkepentingan
REVIEW OF PASSIVE DRAG REDUCTION TECHNIQUES FOR BLUFF ROAD VEHICLES
Get PDFABSTRACT:This paper presents a review of the techniques used to reduce aerodynamic drag over bluff bodies such as cylinders, spheres, 2D bodies with blunt backs and their application to commercial road vehicles. The recent research carried out on the drag reduction is presented and categorised. A new classification of the techniques is introduced and major contributions under them are shown. It can be concluded that there is not much work done with realistic 3D bluff bodies, especially using passive methods.ABSTRAK: Kertas kerja ini membentangkan kaji selidik semula teknik yang digunakan untuk mengurangkan seret aerodinamik ke atas jasad tubir seperti silinder, sfera, jasad 2D dengan belakang tumpul dan aplikasinya terhadap kenderaan jalan raya komersial. Pengurangan seretan dibentangkan dan dikategorikan dengan kajian terkini. Klasifikasi teknik terkini diperkenalkan dan sumbangan utamanya diperbentangkan. Secara kesimpulannya terdapat banyak tugasan yang tidak yang dapat dijalankan dengan menggunakan jasad tubir 3D sebenar, terutamanya dengan penggunaan kaedah pasif
A HEURISTIC CASCADING FUZZY LOGIC APPROACH TO REACTIVE NAVIGATION FOR UAV
Get PDFABSTRACT: The capability of navigating Unmanned Aerial Vehicles (UAVs) safely in unknown terrain offers huge potential for wider applications in non-segregated airspace. Flying in non-segregated airspace present a risk of collision with static obstacles (e.g., towers, power lines) and moving obstacles (e.g., aircraft, balloons). In this work, we propose a heuristic cascading fuzzy logic control strategy to solve for the Conflict Detection and Resolution (CD&R) problem, in which the control strategy is comprised of two cascading modules. The first one is Obstacle Avoidance control and the latter is Path Tracking control. Simulation results show that the proposed architecture effectively resolves the conflicts and achieve rapid movement towards the target waypoint.ABSTRAK: Keupayaan mengemudi Kenderaan Udara Tanpa Pemandu (UAV) dengan selamat di kawasan yang tidak diketahui menawarkan potensi yang besar untuk aplikasi yang lebih luas dalam ruang udara yang tidak terasing. Terbang di ruang udara yang tidak terasing menimbulkan risiko perlanggaran dengan halangan statik (contohnya, menara, talian kuasa) dan halangan bergerak (contohnya, pesawat udara, belon). Dalam kajian ini, kami mencadangkan satu strategi heuristik kawalan logik kabur yang melata untuk menyelesaikan masalah Pengesanan Konflik dan Penyelesaian (CD&R), di mana strategi kawalan yang terdiri daripada dua modul melata. Hasil simulasi menunjukkan bahawa seni bina yang dicadangkan berjaya menyelesaikan konflik dan mencapai penerbangan pesat ke arah titik laluan sasaran.KEYWORDS: fuzzy logic; motion planning; obstacle avoidance; path tracking; reactive navigation; UA
THE IMPACT OF THE PRODUCTION OF NEIGHBOUR WELLS ON WELL PRODUCTIVITY IN A SHALE GAS RESERVOIR
Get PDFABSTRACT: A shale gas reservoir is a self-contained source-reservoir system, characterized by extremely low matrix-permeability and low porosity, which typically requires extensive fracturing to produce gas at commercial rates. This paper presents a simulation experiment, intended to study the impact of well interference on gas recovery in a shale gas reservoir. The simulation model was constructed to study well interference through variation of horizontal well length, fracture half length, number of fracture, and well spacing. The results show that the increment of recovery factor of a well in the presence of neighbour wells is up to 7%. In this study, fracture half length is the most influence parameter on recovery factor, initial rate and reservoir pressure decline. ABSTRAK: Takungan gas syal merupakan sistem sumber-takungan kandung sendiri, khasnya kerana ia mempunyai kebolehtelapan-matriks yang begitu rendah dan keliangan yang rendah. Sifat sebegini memerlukan ia melalui peretakan yang ekstensif untuk menghasilkan gas pada nilai komersial. Kertas kerja ini membentangkan eksperimen simulasi yang bertujuan untuk mengkaji impak perigi interferens terhadap perolehan gas dalam takungan gas syal. Model simulasi di konstruksi untuk mengkaji interferens perigi; iaitu menerusi pelbagai variasi panjang mendatar perigi, retakan separuh panjang dan jarak perigi. Keputusan menunjukkan peningkatan faktor perolehan perigi sebanyak 7% dengan kehadiran perigi bersebelahan. Dalam kajian ini, retakan separuh panjang merupakan ciri utama dalam faktor perolehan, kadar awalan dan penurunan tekanan takungan