bluuebunny/crossref_metadata_2025_split huggingface dataset:
Convection Heat Transfer Modeling of Ag Nanofluid Using Different Viscosity Theories
Authors: Kasaeian Ali Bakhsh 
Published: October 2018

ABSTRACT: In this paper, the effects of adding nanoparticles (including Ag) to a fluid media for improving free convection heat transfer were analysed. The free convective heat transfer was assumed to be in laminar flow regime, and the corresponding calculations and solutions were all done by the integral method. Water, as a Newtonian fluid, was considered as the base and all relevant thermo physical properties of the nanofluids were considered to be unvarying. The calculations performed and the graphs generated showed that, in general, the addition of nanoparticles to the fluid media resulted in an increment or improvement of its heat transfer coefficient. With increase in the concentration of the nanoparticles, the heat transfer rate of the fluid also increased. The increment in heat transfer is also dependent on the nanoparticlesâ€™ thermal conductivity and the viscosity theory which was utilized in the calculations. In this study, four different theories were used to calculate the viscosities of the nanofluids. The effects of viscosity on the nanofluidsâ€™ thermal conductivity were apparent from the calculations which were performed for nanoparticle concentrations of 4% or less.Â ABSTRAK: Kajian ini menganalisis kesan penambahan nanopartikel Ag ke dalam media bendalir bagi tujuan pembaikkan pemindahan haba perolakan bebas. Perolakan bebas diandaikan berada di zon aliran laminar, di mana penyelesaian dan pengiraan telah dilakukan mengunakan kaedah kamilan. Air yang merupakan cecair Newtonian, dianggap sebagai asas dan sifat terma fizikal nanocecair dianggapkan tidak berubah. Mengikut pengiraan yang dilakukan dan graf yang diplotkan, umumnya penambahan nanopartikel kepada media bendalir menyebabkan peningkatan dan pengembangan pekali pemindahan haba. Kadar pemindahan haba meningkat dengan nanopartikel. Peningkatan pemindahan haba juga bergantung kepada pengalir haba nanopartikel dan teori kelikatan yang digunakan. Di dalam kajian ini, empat jenis teori telah digunakan bagi pengiraan kelikatan nanopartikel. Kesan kelikatan ke atas pengalir haba nanocecair sangat jelas kelihatan. Kesemua pengiraan telah dilakukan ke atas kepekatan kurang dari 4%.KEYWORDS: Ag nanofluid, heat transfer, natural convection.
The Parameters Affect on Power Coefficient Vertical Axis Wind Turbine
Authors: Qasim Ahmed Y. , Usubamatov Ryspek , Zain Zuraidah M. , Quad Ghulam Abdul 
Published: October 2018

ABSTRACT: This study describes the design of a special type of vertical axis rotor wind turbine with moveable vertically positioned vanes. The novel design increases the torque in the left side of the wind turbine by increasing the drag coefficient. It also reduces the negative torque of the frame which rotates contrary to the wind in the other side. Two different types of models, having different vane shapes (flat vane and cavity shaped vane), were fabricated. Each type consisted of two models with varying number of frames (three and four frames). The models were tested in a wind tunnel with variable wind speed in order to understand the effect of shape, weight, and number of frames on the power coefficient of the wind turbine.Â ABSTRAK: Di dalam kajian ini, rotor turbin angin berpaksi vertikel sebagai rangka khusus telah direkabentuk dengan lokasi vertikel mudahalih oleh bilah kipas. Rekabentuk ini meningkatkan tork di bahagian kiri turbin angin dengan meningkatkan pekali seretan dan mengurangkan tork negatif rangka yang berputar berlawanan dengan angin pada bahagian lain. Dua jenis model berbentuk berlainan telah difabrikasi (bilah kipas rata dan bilah kipas berbentuk kaviti), dengan setiap jenis mempunyai dua model dengan bilangan rangka yang berlainan (berangka tiga dan berangka empat). Model-model telah diuji di dalam terowong angin dengan kelajuan angin yang berbeza bagi mendapatkan kesan rekabentuk, berat dan bilangan rangka ke atas pekali kuasa.KEYWORDS: design; wind turbine; drag coefficient; vane
PROCESS MODELLING AND DEBOTTLENECKING STUDY OF A VACCINE PRODUCTION
Authors: Mohamed Safri Nurul Huda , Mel Maizirwan , Foo Dominic C.Y. , Ng Denny K.S. , Chew Irene M.L. 
Published: October 2018

ABSTRACT: 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.Â 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.Â 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; optimisation
Investigation of Residual Stresses and Distortion in Welded Pipe-Flange Joint of Different Classes
Authors: Abid Muhammad 
Published: October 2018

ABSTRACT: Pipe and flange joints are commonly used in petrochemical, nuclear and process industries. Commonly, welding is used to make these joints which produces residual stresses and distortions. These stresses have detrimental effects on the structural integrity and service performance of the welded pipe joints. The objective of this study is to investigate the residual stresses and distortions during Gas Metal Arc Welding of pipe of schedule 40, nominal diameter 200 mm with different ANSI flanges of class numbers 150, 300, 600, 900, 1500, and 2500. Welding parameters including: voltage, current and heat as inputs were selected based on the literature available. The behaviour of the flanges of different classes is also discussed. In addition, the finite element methodology presented, in this paper, can be helpful for developing welding procedures for a range of pipe flange welded joint sizes in order to control the residual stresses and deformations. This will lead to optimised performance during bolt up and operating conditions.ABSTRAK: Paip dan sambungan flan biasanya digunakan dalam industri petrokimia, nuklear dan proses. Kimpalan menghasilkan tegasan sisa dan herotan, yang memberikan kesan yang merbahaya ke atas integriti struktur dan prestasi servis sambungan kimpalan paip. Objektif kajian ini adalah untuk mengkaji tegasan sisa dan herotan ketika kimpalan arka logam gas paip berjadual 40, diameter nominal 200mm dengan flan ANSI yang berbeza kelas # 150, 300, 600, 900, 1500, dan 2500. Parameter kimpalan termasuklah; voltan, arus dan haba input yang dipilih berdasarkan literatur sediada. Kelakuan flan yang berbeza kelas telah dibincangkan. Kaedah elemen finit yang dibentangkan adalah berguna dalam membangunkan prosedur kimpalan bagi julat saiz kimpalan flan paip unutk mengawal tegasan sisa dan canggaan i.e. bagi mengoptimakan prestasi ketika bolt up dan sedang beroperasi.Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â KEYWORDS:Â finite element; residual stresses; distortion; welding; pipe-flange joint; different classes
Optimizing PHB and Protease Production by Box Behnken Design
Authors: Amara Amro Abd al fattah 
Published: October 2018

Mixed culture is more suitable to adapt more flexible fermentation process and produce different product simultaneously. In this study a mixed Bacillus culture was investigated for their ability to produce the bioplastic "Polyhydroxybutyrate" and both of the mesophilic and the thermophilic proteases in one flask. Box-Behnken experimental design was used. The produced amount of PHB has been increased significantly. Meanwhile there is a competition between PHB and proteases. The maximum produced amount of PHB using Box-Behnken design was 2.82 g/l/48 h with protease activity equal to 41.9 Units/ml/48 h for thermophilic proteases and 99.65 Units/ml/48 h for mesophilic proteases. Excel solver was used for extra-optimization for the optimum conditions obtained from Box-Behnken experiments and its model. The maximum PHB obtained after using Excel solver was 2.88 g/l/48 h. The maximum mesophilic and thermophilic activities obtained at the same PHB production conditions were 175.68 and 243.38 Units/ml respectively. The model accuracy as obtained from Excel solver was 118.8%, which prove the power of the experimental design in optimizing such complicated process. The strategies used in this study are recommended for the production of PHB and different proteases simultaneously using Bacillus mixed culture. ABSTRAK: Kultur campuran adalah lebih sesuai bagi proses penapaian yang fleksibel dan ia boleh menghasilkan produk yang berbeza secara serentak. Dalam kajian ini keupayaan menghasilkan "Polyhydroxybutyrate" bioplastik serta mesofilik dan termofilik protease dalam satu flask oleh kultur Bacillus campuran telah disiasat. Eksperimen rekabentuk Box-Behnken telah digunakan. Jumlah PHB yang dikeluarkan meningkat dengan ketara dan terdapat persaingan antara PHB dan protease. Jumlah keluaran PHB maksima menggunakan rekabentuk Box-Behnken adalah 2.82 g/l/48 jam dengan aktiviti protease sama dengan 41.9 Unit/ml/48 jam untuk protease termofilik dan 99.65 Unit/ml/48 h untuk protease mesofilik. Solver Excel telah digunakan untuk memperolehi kadar optimum tambahan dari keadaan optimum yang diperolehi dari experimen dan model Box-Behnken. PHB maksimum diperolehi setelah menggunakan solver Excel adalah 2.88 g/l/48 jam. Aktiviti mesofilik dan termofilik maksima diperolehi daripada keadaan pengeluaran PHB yang sama adalah 175.68 dan 243.38 Unit / ml. Ketepatan model diperolehi daripada solver Excel adalah 118.8%, membuktikan kekuatan eksperimen tersebut bagi mengoptimumkan proses yang rumit. Strategi yang digunakan dalam kajian ini adalah disyorkan bagi pengeluaran PHB dan proteas berbeza secara serentak menggunakan kultur Bacillus campuran.KEYWORDS: PHB; proteases; mixed culture; Box-Behnken design.
Performance Analysis of Solar Combined Ejector-Vapor Compression Cycle Using Environmental Friendly Refrigerants
Authors: Kasaeian A. B. , Daviran S. 
Published: October 2018

In this study, a new model of a solar combined ejector-vapor compression refrigeration system has been considered. The system is equipped with an internal heat exchanger to enhance the performance of the cycle. The effects of working fluid and operating conditions on the system performance including COP, entrainment ratio (Ï‰), compression ratio (rp) and exergy efficiency were investigated. Some working fluids suggested are: R114, R141b, R123, R245fa, R600a, R365mfc, R1234ze(e) and R1234ze(z). The results show that R114 and R1234ze(e) yield the highest COP and exergy efficiency followed by R123, R245fa, R365mfc, R141b, R152a and R600a. It is noticed that the COP value of the new solar ejector-vapor compression refrigeration cycle is higher than that of the conventional ejector cycle with R1234ze(e) for all operating conditions. This paper also demonstrates that R1234ze(e) will be a suitable refrigerant in the solar combined ejector-vapor compression refrigeration system, due to its environmental friendly properties and better performance.Â ABSTRAK: Kajian ini menganalisa model baru sistem penyejukan mampatan gabungan ejektor-wap solar.Sistem ini dilengkapi dengan penukar haba dalaman untuk meningkatkan prestasi kitaran.Kesan bendalir bekerja dan keadaan operasi pada prestasi sistem termasuk COP, nisbah pemerangkapan (Ï‰), nisbah mampatan (rp) dan kecekapan eksergi telah disiasat.Beberapa bendalir bekerja yang dicadangkan adalah: R114, R141b, R123, R245fa, R600a, R365mfc, R1234ze(e) dan R1234ze(z).Hasil kajian menunjukkan R114 dan R1234ze(e) menghasilkan COP dan kecekapan eksergi tertinggi diikuti oleh R123, R245fa, R365mfc, R141b, R152a dan R600a.Didapati nilai COP kitaran penyejukan mampatan bagi ejektor-wap solar baru adalah lebih tinggi daripada kitaran ejektor konvensional dengan R1234ze(e) bagi semua keadaan operasi.Kertas kerja ini juga menunjukkan bahawa R1234ze(e) boleh menjadi penyejuk yang sesuai dalam sistem penyejukan mampatan gabungan ejektor -wap solar, kerana ianya mempunyai prestasi yang lebih baik serta sifatnya yang lebih mesra alam sekitar.Â KEYWORDS: environmental friendly refrigerants; solar combined ejector-vapor compression cycle; R1234ze(e)
THE IMPACT OF THE PRODUCTION OF NEIGHBOUR WELLS ON WELL PRODUCTIVITY IN A SHALE GAS RESERVOIR
Authors: Nugrahanti Asri , Guntoro Agus , Fathaddin Muhammad Taufiq , Djohor Denny Suwanda 
Published: October 2018

ABSTRACT: 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.Â 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.Â Model simulasi di konstruksi untuk mengkaji interferens perigi; iaitu menerusi pelbagai variasiÂ panjang mendatar perigi, retakan separuh panjang dan jarak perigi.Â 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.
WHERE DID GENERAL MOTORS GO WRONG WITH THE IGNITION SWITCH RECALL?
Authors: Shaout Adnan , Dusute Cassandra 
Published: October 2018

ABSTRACT: When it comes to purchasing a new car, a buyer expects the car to be safe and reliable. It is the responsibility of the automaker to ensure that those expectations are met. However, to err is human; recalls are a necessary part of life. When a recall happens, it then becomes the responsibility of the automaker to issue the recall in a timely manner. However, that was not the case with the General Motors (GM) ignition switch recall. The focus of this paper will be on the GM ignition switch, including sections regardingÂ the problem with the switch, who may have been responsible for approving the switch, and possible suggestions on how GM could have prevented the recall. ABSTRAK: Ketika keputusan diambil untuk membeli kereta baru, pembeli mahukan kereta yang selamat dan berwibawa. Adalah menjadi kewajipan pembuat kereta tersebut untuk memastikan bahawa harapan tersebut tercapai.Â Namun, kita hanyalah manusia; penarikan balik menjadi kemestian. Apabila berlakunya perihal menarik balik produk, ianya adalah tanggungjawab pembuat kereta untuk menariknya dengan cara yang sepatutnya.Â Namun dalam kes tarik balik suis pencucuh General Motors (GM) ini tidak berlaku. Kertas kerja ini akan memfokuskan kepada suis pencucuh GM; termasuklah masalah suis, pihak yang bertanggungjawab meluluskannya dan beberapa cadangan bagaimana sepatutnya GM boleh menghalang isu penarikan balik ini.KEYWORDS: approval process; validation plan; performance testing; ignition switch; embedded system; torque requirements; automotive recalls; industry
STUDIES ON THE EFFECT OF ARTIFICIAL AGEING HARDNESS ON TENSILE PROPERTIES AND IMPACT STRENGTH OF AL-6SI-0.5MG-2NI ALLOY
Authors: Hossain Abul , Kurny Abu Syedwais 
Published: October 2018

The 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.Â KEYWORDS: Al-6Si-0.5Mg-2Ni alloy; ageing; hardness; tensile properties; impact strength;
HARMONIC COMPONENTS ESTIMATION IN POWER SYSTEM USING BACTERIAL FORAGING OPTIMIZATION ALGORITHM AND STOCHASTIC GRADIENT ALGORITHM WITH VARIABLE FORGETTING FACTOR
Authors: Mohammadzadeh Ahmad , Sadati Jalil , Rezaie Behrooz 
Published: October 2018

In this paper, a hybrid configuration algorithm called stochastic gradient method with variable forgetting factor (SGVFF) is proposed to better estimate unknown parameters in a power system such as amplitude and phase of harmonics using variable forgetting factor following the bacterial foraging optimization algorithm (BFO). It must be mentioned that harmonic estimation is a nonlinear problem and using linear optimization algorithms for solving this problem reduces the convergence speed. Thus, BFO algorithm is used for initial estimation. In this paper, first, using little information and by applying BFO algorithm in an off-line procedure initial value for SGVFF algorithm is achieved and then SGVFF algorithm is gained in an on-line procedure. In the hybrid algorithm applied in this paper, amplitudes and phases are estimated simultaneously. Simulation results indicate that the proposed method has faster convergence speed, better performance and higher accuracy in a noisy system in comparison with recursive least squares variable forgetting factors algorithm (RLSVFF). This proves the superiority of the proposed method.KEYWORDS:Â Power system harmonic; BFO algorithm; SGVFF method; RLSVFF method
INTELLIGENT FRACTIONAL ORDER ITERATIVE LEARNING CONTROL USING FEEDBACK LINEARIZATION FOR A SINGLE-LINK ROBOT
Authors: Ghasemi Iman , Ranjbar Noei Abolfazl , Sadati Jalil 
Published: October 2018

In this paper, iterative learning control (ILC) is combined with an optimal fractional order derivative (BBO-Da-type ILC) and optimal fractional and proportional-derivative (BBO-PDa-type ILC). In the update law of Arimoto's derivative iterative learning control, a first order derivative of tracking error signal is used. In the proposed method, fractional order derivative of the error signal is stated in term of 'sa' where Â to update iterative learning control law. Two types of fractional order iterative learning control namely PDa-type ILC and Da-type ILC are gained for different value of a. In order to improve the performance of closed-loop control system, coefficients of both Â and Â learning law i.e. proportional , derivative Â and Â are optimized using Biogeography-Based optimization algorithm (BBO). Outcome of the simulation results are compared with those of the conventional fractional order iterative learning control to verify effectiveness of BBO-Da-type ILC and BBO-PDa-type ILC
A Proposed Method for Improving the Performance of P-Type GaAs IMPATTs
Authors: A. El-Motaafy H. 
Published: October 2018

A special waveform is proposed and assumed to be the optimum waveform for p-type GaAs IMPATTs. This waveform is deduced after careful and extensive study of the performance of these devices. The results presented here indicate the superiority of the performance of the IMPATTs driven by the proposed waveform over that obtained when the same IMPATTs are driven by the conventional sinusoidal waveform. These results are obtained using a full-scale computer simulation program that takes fully into account all the physical effects pertinent to IMPATT operation. In this paper, it is indicated that the superiority of the proposed waveform is attributed to its ability to reduce the bad effects that usually degrade the IMPATT performance such as the space-charge effect and the drift-velocity dropping below saturation effect. The superiority is also attributed to the ability of the proposed waveform to improve the phase relationship between the terminal voltage and the induced current.Key Words: Computer-Aided Design, GaAs IMPATT, Microwave Engineering
High Speed Submarine Optical Fiber Communication System:Pressure and Temperature Effects
Authors: Mohammed A. A. 
Published: October 2018

In the present paper, the performance of high speed submarine optical fiber cable systems is investigated, taking into account both the pressure and the temperature effects. Both the pressure and the temperature are depth-dependent variables, while both the spectral losses and the dispersion effects are temperature as well as wavelength dependent variables. Two important cases with real fibers are processed: a case with dispersion cancellation and a case without dispersion cancellation. It is found that the ocean pressure (due to the depth) shifts the dispersion-free wavelength towards the third communication window. In general, as the depth increases the maximum transmitted bit rate increases in the range of interest. The system capacity as well as the spectral losses, and the dispersion effects are parametrically investigated over wide-range ranges of the set of affecting parameters {wavelength, ocean depth (and consequently the ocean pressure and temperature), and the chemical structure}. Key Words: Submarine Optical Fiber, Undersea Optical Communication, Pressure and Temperature Effects, Transoceanic Optical Communications