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INFLUENCE OF DIFFERENT PERCENTAGE BOILER ASH-BASED GEOPOLYMER IN LATERITE SOIL
Get PDFThe waste generation of palm oil boiler ash has been one of its big problems as it is less used and deposited in landfills as a by-product. Geopolymer is a new green technology that has been intensively studied in concrete applications. However, few studies on geopolymers have been conducted in soil applications. Thus, this study investigated the influence of palm oil boiler ash-based geopolymer in laterite soil strength. Different percentages, 5, 10, 15, and 20% of geopolymer mixtures, were added to laterite soil. The process of producing a geopolymer binder was performed by sieving boiler ash (150 µm), then mixing with sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) as an alkaline activator at a ratio of 1:2. This material effectiveness was tested through compaction test using a standard proctor, unconfined compressive strength, and the scanning electron microscope (SEM). 15% of geopolymer in laterite soil indicated the best-mixed design with a maximum dry density of 2.23 Mg/m3 with a moisture content of 13.58%. The unconfined compressive strength test at curing times of zero, seven, and twenty-eight days on the LS-15.0 GPOBA sample, show a slightly increased strength of 47, 58, and 76 kPa, respectively. The SEM images proved that the geopolymer gel's development stabilized the soil structure from a loose structure to a denser soil structure. This study aims to investigate the influence of geopolymer in laterite soil. Boiler ash as an alternative material in geotechnical applications was studied to understand and develop new green alternative materials to sustain the environment from industrial waste and to enhance laterite soil properties.
ABSTRAK: Abu kelapa sawit adalah salah satu sisa utama yang terhasil dari industri kelapa sawit tetapi penggunaannya kurang dimanfaatkan dan dibuang ke tempat pembuangan sampah. Teknologi hijau baru yang dikenali sebagai geopolimer telah dikaji secara intensif dengan kekuatan konkrit tetapi hanya sedikit kajian telah dibuat dalam penggunaan tanah. Tujuan kajian ini adalah bagi mengesan geopolimer berasaskan abu kelapa sawit terhadap kekuatan tanah laterit. Peratusan campuran geopolimer yang berbeza (0, 5, 10, 15 dan 20%) dicampur pada tanah laterit. Bagi menghasilkan geopolimer, saiz 150 ?m abu kelapa sawit disintesis dengan kombinasi bahan kimia natrium hidroksida (NaOH) dan natrium silikat (Na2SiO3) pada nisbah 1:2 bagi semua campuran sebagai pengaktif alkali. Ujian terhadap keberkesanan bahan adalah melalui proses ujian pemampatan menggunakan proktor standard, kekuatan pemampatan tidak terbatas, dan Pengimbas Mikroskop Elektron (SEM). Berdasarkan dapatan ujian pemadatan, 15% geopolimer di tanah laterit menunjukkan campuran terbaik dengan memberikan kepadatan pengeringan maksimum 2.23 Mg/m3 pada kelembapan 13.58%. Ujian kekuatan mampatan tidak terbatas pada masa pempolimeran sebanyak 0, 7 dan 28 hari diuji pada sampel LS-15.0GPOBA bagi menguji kekuatan campuran. Dapatan menunjukkan kekuatan geopolimer sedikit meningkat pada 47, 58 dan 76, masing-masing. Imej SEM membuktikan pengembangan gel geopolimer menstabilkan struktur tanah daripada struktur lopong kepada struktur tanah padat. Oleh itu, abu kelapa sawit berasaskan geopolimer dan tanah laterit berpotensi sebagai alternatif bagi merawat tanah dalam aplikasi geoteknik dan berpotensi mengurangkan kadar kebolehtelapan
MACHINE-LEARNING-BASED EVALUATION OF CORROSION UNDER INSULATION IN FERROMAGNETIC STRUCTURES
Get PDFCorrosion under insulation CUI is one of the challenging problems in pipelines used in the gas and oil industry as it is hidden and difficult to detect but can cause catastrophic accidents. Pulsed eddy current (PEC) techniques have been identified to be an effective non-destructive testing (NDT) method for both detecting and quantifying CUI. The PEC signal’s decay properties are generally used in the detection and quantification of CUI. Unfortunately, the well-known inhomogeneity of the pipe material’s properties and the presence of both cladding and insulation lead to signal variation that reduces the effectiveness of the measurement. Current PEC techniques typically use signal averaging in order to improve the signal-to-noise ratio (SNR), with the drawback of significantly-increasing inspection time. In this study, the use of Gaussian process regression (GPR) for predicting the thickness of mild carbon steel plates has been proposed and investigated with no signal averaging used. With mean absolute errors (MAE) of 0.21 mm, results show that the use of GPR provides more accurate predictions compared to the use of the decay coefficient, whose averaged MAE is 0.36 mm. This result suggests that the GPR-based method can potentially be used in PEC NDT applications that require fast scanning.
ABSTRAK: Hakisan di bawah penebat CUI adalah salah satu masalah yang mencabar dalam saluran paip yang digunakan dalam industri gas dan minyak kerana tersembunyi dan sukar dikesan tetapi boleh menyebabkan bencana. Teknik Pulsed eddy current (PEC) telah dikenal pasti sebagai kaedah ujian bukan pemusnah yang berkesan (NDT) untuk mengesan dan mengukur CUI. Sifat kerosakan isyarat PEC umumnya digunakan dalam pengesanan dan pengukuran CUI. Malangnya, sifat tidak tepat yang terkenal dari sifat bahan paip dan kehadiran pelapisan dan penebat menyebabkan variasi isyarat yang mengurangkan keberkesanan pengukuran. Teknik PEC semasa biasanya menggunakan rata-rata isyarat untuk meningkatkan nisbah isyarat-ke-kebisingan (SNR), dengan kelemahan peningkatan masa pemeriksaan dengan ketara. Dalam kajian ini, penggunaan regresi proses Gauss (GPR) untuk meramalkan ketebalan plat keluli karbon ringan telah diusulkan dan diselidiki dan tidak ada rata-rata isyarat yang digunakan. Dengan ralat mutlak (MAE) 0,21 mm, hasil menunjukkan bahawa penggunaan GPR memberikan ramalan yang lebih tepat dibandingkan dengan penggunaan pekali peluruhan, yang rata-rata MAE adalah 0,36 mm. Hasil ini menunjukkan bahawa kaedah berasaskan GPR berpotensi digunakan dalam aplikasi PEC NDT yang memerlukan pengimbasan pantas
ANALYTICAL AND NUMERICAL THERMAL ANALYSIS ON FRICTION STIR WELDING USING POLYGONAL TOOL PIN
Get PDFFrictional heat generation in the tool/matrix interface followed by the stirring of material along the weld line causes plasticized solid state joining in friction stir welding. In this paper, the existing torque based thermo-mechanical model for the tools with cylindrical pins is remodified for the polygonal tool pin profile by introducing novel multiplication factors with respect to the number of sides in the tool pin geometry. The variation in the effective heat supply with respect to the chosen pin geometry was analyzed. A comparative analysis of the proposed analytical model with the existing model was also carried out to understand the accuracy of the proposed model. Furthermore, a transient thermal numerical modelling was carried out in the view of understanding the change in process peak temperature in the stir zone and change in temperature gradient along the heat affected zone with respect to the change in pin geometry for the opted set of process input parameters. An analytically estimated heat-input-based numerical model was adopted in the present study. It was observed that the process peak temperature was directly proportional to the number of sides in the tool pin.
ABSTRAK: Penjanaan haba geseran antara muka pada alat/matrik diikuti dengan pengacauan material sepanjang garis kimpalan menyebabkan keadaan plastik pepejal melekat bersama geseran kimpalan pengacau. Kajian ini berkaitan tork sedia ada berdasarkan model mekanikal-terma bagi alat pin silinder yang terubah suai bagi profil pin alat poligon dengan memperkenalkan faktor gandaan berdasarkan bilangan sisi geometri alat pin. Perubahan pada bekalan haba efektif berdasarkan geometri pin pilihan telah dikaji. Analisis bandingan pada model analitik yang dicadang bersama model sedia ada, telah dilakukan bagi memahami ketepatan model cadangan. Tambahan, model transien numerikal terma telah dibuat bagi memahami proses perubahan suhu puncak ketika zon pengacauan dan perubahan gradien suhu sepanjang zon terkena haba perubahan geometri pin pada set proses parameter input terpilih. Kajian ini mengaplikasi model numerik berdasarkan input anggaran haba secara analitik. Dapatan kajian menunjukkan suhu puncak proses adalah berkadar langsung dengan bilangan sisi pin alat
A REVIEW OF FLOW CONFLICTS AND SOLUTIONS IN SOFTWARE DEFINED NETWORKS (SDN)
Get PDF Software Defined Networks (SDN) are a modern networking technology introduced to simplify network management via the separation of the data and control planes. Characteristically, flow entries are propagated between the control plane layer and application or data plane layers respectively while following flow table instructions through open flow protocol. More often than not, conflicts in flows occur as a result of traffic load and priority of instructions in the data plane. Several research works have been conducted on flow conflicts in SDN to reduce the effect of conflict. The flow conflict solutions in SDN have three main limitations. First, the OpenFlow table may still cause a defect in the security module according to the priority and action matching in the open flow in the control plane. Second, flow conflict detection requires more time for flow tracking and incremental update, whereas in such a case, delay affects the efficiency of SDN. Besides, the SDN algorithm and mechanism have substantially high memory requirement for instruction and proper functioning. Third, most of the available algorithms and detection methods used to avoid flow conflicts have not fully covered the security model policy. This study reviews these limitations and suggest solutions as future open research directions.
ABSTRAK: Rangkaian Perisian Tertentu (SDN) adalah teknologi rangkaian moden yang diperkenalkan bagi memudahkan pengurusan rangkaian melalui pecahan data dan kawalan permukaan. Seperti biasa, aliran kemasukan disebar luas antara lapisan permukaan kawalan dan aplikasi atau lapisan permukaan data masing-masing, sambil mengikuti arahan meja melebar melalui protokol aliran terbuka. Kebiasaannya konflik dalam aliran berlaku disebabkan oleh beban trafik dan keutamaan arahan pada permukaan data. Beberapa kajian dibuat terhadap konflik aliran SDN bagi mengurangkan kesan konflik. Solusi konflik aliran dalam SDN mempunyai tiga kekurangan besar. Pertama, jadual Aliran Terbuka mungkin masih menyebabkan kekurangan dalam modul keselamatan berdasarkan keutamaan dan tindakan persamaan dalam aliran terbuka permukaan kawalan. Kedua, pengesanan aliran konflik memerlukan lebih masa bagi pengesanan aliran dan peningkatan kemaskini, kerana setiap penangguhan memberi kesan terhadap kecekapan SDN. Selain itu, algoritma SDN dan mekanisme memerlukan memori yang agak besar bagi memproses arahan dan berfungsi dengan baik. Ketiga, kebanyakan algoritma dan kaedah pengesanan yang digunakan bagi mengelak konflik pengaliran tidak sepenuhnya dilindungi polisi model keselamatan. Oleh itu, kajian ini meneliti kekurangan dan memberi cadangan penambahbaikan bagi arah tuju kajian masa depan yang terbuka
SERIES-SERIES AND SERIES-PARALLEL COMPENSATION TOPOLOGIES FOR DYNAMIC WIRELESS CHARGING
Get PDFElectric vehicles (EV) have gained worldwide attention since the implementation of a wireless power transfer (WPT) to charge their batteries. With WPT, it can be very convenient for EV to be charged dynamically. Nevertheless, there are some issues in dynamic WPT, such as maintaining the power transfer efficiency. Several factors that lead to these problems include disruption of the alignment and the optimum distance between the transmitter and receiver coils. It is thus contributing to the loss of power efficiency when charging the EV. Not to mention, manufacturers build different specifications of EV charging station for different types of EV models in order to meet customer demands. An incompatible charging device will not utilize EV wireless charging to its maximum potential. Hence, to improve the power output capability as well as stabilizing the maximum power transfer during the charging process, a compensation circuit is added to the system. This article focuses on comparing two available compensation circuits (series-series (SS) topology and series-parallel (SP) topology) under the application of dynamic wireless charging. The simulations are conducted using NI Multisim based on the relationship of power transfer efficiency with resonance frequency, coefficient of coupling, and the load resistance. The WPT efficiency for SP-topology shows that it is sensitive to the change of resonance frequency and coupling coefficient, whereas SS-topology maintains good efficiency during the WPT process. Nonetheless, SS-topology performance suffers efficiency loss when paired with a higher load, while SP-topology acts differently. This article will observe the best conditions on the selected compensation designs for better application in EV charging systems in a moving state.
ABSTRAK: Kenderaan elektrik (EV) telah menarik perhatian dunia sejak pelaksanaan alih kuasa wayarles (WPT) bagi mengecas bateri. Melalui WPT, EV lebih mudah kerana ia boleh dicas secara dinamik. Namun, pengecasan dinamik WPT turut mengalami masalah, seperti mengimbang kecekapan pemindahan kuasa. Beberapa faktor yang membawa kepada masalah ini adalah kerana terdapat gangguan penjajaran dan jarak optimum antara gegelung pemancar dan penerima. Kerana ini, ia menyumbang kepada kehilangan kecekapan kuasa semasa mengecas EV. Pengeluar juga membina spesifikasi stesen pengisian EV berlainan mengikut jenis model EV demi memenuhi permintaan pelanggan. Namun, platform pengecas EV yang berbeza, tidak dapat mengecas EV secara wayarles dengan maksimum. Oleh itu, bagi membaiki keupayaan jana kuasa serta menstabilkan pengeluaran kuasa maksimum semasa proses pengecasan, litar gantian ditambah ke dalam sistem. Artikel ini memberi keutamaan pada dua litar gantian berbeza (topologi bersiri (SS) dan siri-selari (SP)) di bawah aplikasi pengecasan wayarles dinamik. Simulasi dibuat menggunakan NI Multisim mengikut kecekapan pemindahan kuasa dengan frekuensi resonan, pekali gandingan dan rintangan beban. Kecekapan WPT bagi topologi-SP menunjukkan ianya sensitif pada perubahan frekuensi resonan dan pekali gandingan. Manakala topologi-SS kekal cekap semasa proses WPT. Walau bagaimanapun, prestasi topologi-SS berkurangan ketika diganding dengan beban besar, begitu juga berbeza bagi topologi-SP. Artikel ini akan mengkaji keadaan terbaik pada reka bentuk gantian terpilih bagi aplikasi EV dalam sistem pengecasan bergerak
MODEL ANALYZING FOR REUSING GOLD WIRE CAPILLARY IN THE GOLD WIRE BONDING PROCESS
Get PDFManufacturing process improvement is necessary for manufacturers to gain business advantages. Re-using or increasing the useful lives of machine parts is considered to be a process of performance improvement. To re-use parts, the manufacturers must know the effects of the factors related to workpieces' qualities to prevent defects. This research study aims at presenting the results of analysing the effects of the factors and mathematical models for bond shear strength when reusing gold wire bonding capillary in the gold wire bonding process of integrated circuit (IC) products using design experiment. The operation factors in the reference experiment, including bond force, bond time, USG current, EFO current and EFO gap, are investigated. The Fractional Factorial Design was used to determine five factors that affect the bond shear strength. The analysis of the results show that the bond force is a significant factor where increasing bond force factors leads to increasing bond shear strength. In the end, a Regression model of bond shear strength is obtained to show the result between the bond shear strength and effect of factors.
ABSTRAK: Proses pembaharuan pengilangan adalah penting untuk para pengilang bagi memperoleh keuntungan bisnes. Guna-semula atau menambah jangka hayat pada bahagian-bahagian tertentu pada mesin adalah dianggar sebahagian proses penambahbaikan prestasi mesin. Bagi mengguna semula bahagian-bahagian ini, pengilang mesti mengetahui akibat sesuatu faktor berkaitan kualiti bahan bagi mengelak kecacatan. Kajian ini bertujuan menyampaikan dapatan kajian melalui kesan faktor dan model matematik pada kekuatan ricihan ikatan apabila mengguna semula wayar emas melalui proses kapilari ikatan wayar emas pada produk litar bersepadu melalui rekaan eksperimen. Faktor operasi melalui rujukan eksperimen dari daya ikatan, masa ikatan, arus USG, arus EFO dan jarak EFO dikaji. Rekaan Faktorial Pecahan digunakan bagi mendapatkan lima faktor yang mempengaruhi kekuatan ricihan ikatan. Dapatan kajian menunjukkan daya ikatan merupakan faktor penting di mana, pertambahan faktor daya ikatan menguatkan ricihan ikatan. Akhirnya, model Regression kekuatan ricihan ikatan diperoleh bagi menjelaskan dapatan kajian antara kekuatan ricihan ikatan dan kesan faktor
MECHANICAL PROPERTIES, WATER ABSORPTION, AND FAILURE ANALYSES OF KENAF FIBER REINFORCED EPOXY MATRIX COMPOSITES
Get PDFThe potential of natural fibers as one of the candidate materials in the production of fiber-reinforced polymer composites have been widely investigated. In the current study, natural fiber-reinforced polymer composite was fabricated by employing woven kenaf fiber as a reinforcing agent with epoxy resin that acts as a matrix constituent. This composite sample was fabricated using the application of the vacuum infusion method in which the content of kenaf fibers was varied from 30 vol.%, 40 vol.%, and 50 vol.%. The effects of different fiber loadings toward mechanical and physical properties as well as failure properties of kenaf composite were then evaluated. Kenaf composites were subjected to mechanical tests including tensile and flexural tests. The result shows that the highest tensile strength and modulus were attained at 76.67 MPa and 2.31 GPa, respectively with kenaf composite fabricated with 40 vol.% fiber content. Meanwhile, the highest flexural strength and modulus were recorded at 61.24 MPa and 4.20 GPa, also corresponding to kenaf composite that is loaded with 40 vol.% fibers. Fiber pull-out failure was able to be detected in fabricated kenaf composites. Meanwhile, fiber breakage resulting from flexural failure could also be observed in the kenaf composite samples. Apart from that, it was found that as more kenaf fiber was loaded in the composites, the rate of water absorption tended to increase where the highest rate of water absorption was found at 43.33%, displayed by kenaf composite with 50 vol.% of fiber content.
ABSTRAK: Potensi gentian semula jadi sebagai salah satu bahan dalam penghasilan komposit polimer bertetulang gentian telah banyak dikaji. Dalam kajian terkini, komposit polimer yang diperkuat dengan gentian semula jadi dibuat dengan menggunakan serat kenaf tenunan sebagai agen penguat dan resin epoksi yang bertindak sebagai matriks. Sampel komposit ini dibuat menggunakan kaedah infusi vakum di mana kandungan serat kenaf digunakan adalah 30 vol.%, 40 vol.%, dan 50 vol.%. Kesan kandungan serat yang berbeza terhadap sifat mekanikal dan fizikal serta sifat kegagalan komposit kenaf kemudiannya dinilai. Komposit Kenaf diuji dengan ujian tegangan dan lenturan. Hasilnya menunjukkan bahawa kekuatan tegangan dan modulus tertinggi dicapai pada 76.67 MPa dan 2.31 GPa, milik komposit kenaf yang dibuat dengan kandungan serat 40 vol.%. Sementara itu, kekuatan dan modulus lenturan tertinggi dicatatkan pada 61.24 MPa dan 4.20 GPa juga milik komposit kenaf yang dimuatkan dengan serat 40% vol. Kegagalan serat terkeluar dapat dikesan pada komposit kenaf buatan. Sementara itu, kerosakan serat akibat kegagalan lenturan juga dapat dilihat pada sampel komposit kenaf. Selain itu, didapati bahawa semakin banyak serat kenaf yang dimuatkan dalam komposit, cendurung meningkatkan kadar penyerapan air di mana kadar penyerapan air tertinggi didapati pada 43.33% yang ditunjukkan oleh komposit kenaf dengan kandungan serat 50% vol
ENHANCEMENT OF THE CALORIFIC VALUE OF EM1707PTY FRUIT BUNCH (EFB) BY ADDING MUNICIPAL SOLID WASTE AS SOLID FUEL IN GASIFICATION PROCESS
Get PDFEmpty fruit bunch (EFB), a biomass-based waste, was deemed a potential replacement for fossil fuel. It is renewable and carbon neutral. The efficient management of this potential energy will help to deal with the problem associated with fossil fuels. However, a key parameter for evaluating the quality of raw material (EFB) as a fuel in energy applications is the calorific value (CV). When this CV is low, then its potential utilization as feedstock will be restricted. To tackle this shortcoming, we propose to add municipal solid waste to enhance energetic value. Thus, two major issues will be solved: managing solid residues and contributing an alternative energy source. This study aimed to investigate the possibility of mixing EFB and municipal solid waste (MSW) to make clean energy that is conscious of the environment (climate change) and sustainable development. The selected MSW, comprising of plastics, textiles, foam, and cardboard, were mixed, with EFB at various ratios. Proximate analysis was used to determine moisture content, ash, volatiles, and fixed carbon, whilst elemental analysis, is used to determine CHNS/O for MSW, EFB and their various mixtures. The CV of each element was also measured. The research revealed a significant increase in the calorific value of EFB by mixing it with MSW according to MSW/EFB ratios: 0.25; 0.42; 0.66; 1.00 and 1.50 the corresponding calorific values in (MJ/kg) were 19.77; 21.22; 22.67; 27.04 and 28.47 respectively. While the calorific value of pure EFB was 16.86 MJ/kg, the mixing of EFB with MSW promoted the increase in the CV of EFB to an average of 23.83MJ/kg. Another potential environmental benefit of applying this likely fuel was the low chlorine (0.21 wt. % to 0.95 wt. %) and sulfur concentrations (0.041 wt. % to 0.078 wt.%). This potential fuel could be used as solid refuse fuel (SRF) or refuse-derived fuel (RDF) in a pyrolysis or gasification process with little to no environmental effects.
ABSTRAK: Tandan buah kosong (EFB), sisa berasaskan biojisim, adalah berpotensi sebagai pengganti bahan bakar fosil. Ia boleh diperbaharui dan karbon neutral. Pengurusan berkesan pada potensi tenaga ini dapat membantu mengatasi masalah melibatkan bahan bakar fosil. Namun, kunci parameter bagi menilai kualiti bahan mentah (EFB) sebagai bahan bakar dalam aplikasi tenaga adalah nilai kalori (CV). Apabila CV rendah, potensi menjadi stok suapan adalah terhad. Sebagai penyelesaian, kajian ini mencadangkan sisa pepejal bandaran ditambah bagi meningkatkan nilai tenaga. Oleh itu, dua isu besar dapat diselesaikan: mengurus sisa pepejal dan menambah sumber tenaga alternatif. Kajian ini bertujuan mengkaji potensi campuran tandan buah kosong (EFB) dan sisa pepejal bandaran (MSW) bagi menghasilkan tenaga bersih dari sudut persekitaran (perubahan iklim) dan pembangunan lestari. Pemilihan MSW, terdiri daripada plastik, tekstil, gabus dan kadbod, dicampurlan dengan pelbagai nisbah EFB. Analisis proksimat telah digunakan bagi mendapatkan kandungan kelembapan, abu, ruapan, dan karbon tetap, manakala analisis asas telah digunakan bagi mendapatkan CHNS/O bersama MSW, EFB dan pelbagai campuran lain. Nilai kalori (CV) setiap elemen turut diukur. Dapatan kajian menunjukkan penambahan ketara dalam nilai kalori EFB dengan campuran bersama MSW berdasarkan nisbah MSW/EFB 0.25; 0.42; 0.66; 1.00 dan 1.50 nilai kalori sepadan (MJ/kg) adalah 19.77; 21.22; 22.67; 27.04 dan 28.47 masing-masing. Manakala nilai kalori EFB tulen adalah 16.86 MJ/kg, campuran EFB dan MSW menunjukkan kenaikan CV dengan EFB pada purata 23.83MJ/kg. Antara potensi semula jadi lain adalah dengan mencampurkan bahan bakar ini dengan kalori rendah (0.21 wt. % kepada 0.95 wt. %) dan kepekatan sulfur (0.041 wt. % kepada 0.078 wt.%). Bahan bakar ini berpotensi sebagai bahan bakar pepejal sampah (SRF) atau bahan bakar yang terhasil dari pepejal sampah (RDF) melalui proses pirolisis atau proses gasifikasi yang sedikit atau tiada kesan langsung terhadap persekitaran
MICROWAVE IRRADIATION OPTIMIZATION FOR EFFICIENT LIGNIN REMOVAL FROM COCOA SHELL WASTE USING ALKALI
Get PDFThis paper reports a study to determine the optimum conditions of microwave in assisting alkali treatment for removing lignin from cocoa shell waste (CSW). The CSW was mixed with 5% of NaOH solution at the ratio of 1: 10 of weight to volume of the alkaline before being irradiated in a microwave oven. Various microwave powers (200-400 W), temperature settings (60-80 °C) and irradiation times (10-20 min) were tested on 15 samples set by the Box-Behnken design. The lignin removal was analysed using a 72 % sulfuric acid treatment method. A quadratic equation was employed to the response surface and statistical analysis conducted to confirm the adequacy of the model. The plots show that the optimum microwave conditions are 400 W, 76 °C and 19 min, which were capable to remove 86.57% of lignin. Thermogravimetric analysis and micrographs revealed different decomposition temperature of lignin and morphology of extensively-pored surface of treated CSW, respectively.
ABSTRAK: Kajian ini adalah berkaitan penentuan keadaan optimal ketuhar gelombang mikro bagi membantu menyingkirkan lignin daripada sisa kulit biji koko (CSW) menggunakan rawatan alkali. CSW dicampurkan dengan larutan NaOH 5 % pada nisbah 1:10 berat kepada isipadu larutan alkali sebelum campuran dipanaskan ke dalam ketuhar gelombang mikro. Pelbagai keadaan ujian dibuat pada ketuhar gelombang mikro seperti tenaga (200-400 W), suhu ketuhar (60-80 °C) dan masa pemanasan (10-20 min) ke atas 15 sampel mengikut reka bentuk statistik Box-Behnken. Kadar penyingkiran lignin ditentukan dengan menggunakan kaedah rawatan larutan asid sulfurik berkepekatan 72 %. Persamaan kuadratik telah digunakan ke atas permukaan respon dan analisis statistik telah dilakukan bagi memastikan kesesuaian model. Plot-plot menunjukkan keadaan optima ketuhar gelombang mikro adalah pada 400 W, 76 °C dan 19 min iaitu berupaya menyingkirkan sebanyak 86.57% lignin. Analisis thermogravimetri dan mikrograf masing-masing menunjukkan perbezaan suhu penguraian lignin dan morfologi permukaan CSW yang dirawat didapati berliang dengan banyaknya
INVESTIGATION OF MULTI-ZONE MODELS FOR SPARK IGNITION ENGINE FUELED WITH ETHANOL
Get PDFThis research is aimed at investigating the effect of using ethanol (E100) in multi-zone model analysis consisting of multi-combustion chamber zoning cases. The first case considered is a three-zone model that has an unburned zone, burned zone, and transitory zone. The second case model is also three-zone, consisting of an unburned zone and two partitioned burned zones. The burned zone was imagined partitioned into burned zone-1 and burned zone-2 under uneven fuel distribution having different equivalent ratios. The third case is a four-zone model including two regions of burned zone, an unburned zone and a transitory zone, which is unburned burned zone containing a mixture of unburned and burned gases. Arbitrary constants for each of the unburned (CC1) and burned (CC2) Zone leakages in the unburned burned Zone are 0.00025, 0.0005, 0.001, 0.002, 0.005, 0.1 and 0.5. The Mass Fraction Burned (MFB) for zone-1, x1 and burned zone-2, x2 are computed using Partitioned Burnt Zones Ratios (PBZR) of 2:8, 3:7, 4:6, 5:5, 6:4, 7:3 and 8:2. Two equivalent ratios, one for each fuel MFB (?1, ?2), (0.8, 0.6) and (0.6, 0.8) are analyzed using fuel blends of varying percentage. A comparison of values of the three zoning cases is done using peak values from the three-zone models to evaluate the four-zone model. The model was compared with a spark ignition engine (SIE) operating with a premium motor spirit (PMS) serving as baseline. The engine operating conditions were set at an engine speed of 2000 rpm, -35bTDC ignition time, and burn duration at 60 oC. The indicated mean effective pressure (IMEP), thermal efficiency (?), cylinder pressure and emission fraction from the developed models and those of two-zone analysis obtained agreed with literature values. The result showed it is undesirable to have a high volume of burned charge as infiltrate. The three-zone segmented model predicted the highest engine thermal efficiency and peak pressure at mass burn ratio of 7:3. A general reduction in N2 emission was observed for the three-zone transitional and four-zone models.
ABSTRAK: Kajian ini menilai kesan etanol (E100) dalam analisis model zon-berbilang yang terdapat pada masalah pengezonan kebuk pembakaran-berbilang. Kes pertama yang diambil kira adalah model tiga-zon yang mempunyai zon tidak terbakar, zon terbakar dan zon peralihan. Model kedua merupakan juga tiga-zon yang terdiri daripada zon tidak-terbakar dan dua zon bahagian yang terbakar. Zon yang terbakar dibahagikan kepada zon-1 terbakar dan zon-2 terbakar di bawah kebakaran tidak sekata yang mempunyai nisbah berlainan. Kes ketiga adalah model zon-keempat termasuk dua kawasan zon terbakar, zon tidak-terbakar dan zon peralihan iaitu zon terbakar tidak-terbakar di mana ia adalah campuran gas terbakar dan tidak-terbakar. Tetapan sebarangan bagi setiap zon kebocoran tidak-terbakar (CC1) dan terbakar (CC2) dalam zon terbakar tidak-terbakar adalah 0.00025, 0.0005, 0.001, 0.002, 0.005, 0.1 dan 0.5. Pecahan Jisim Terbakar (MFB) bagi zon-1, x1 dan zon-2 terbakar, x2 dikira menggunakan Nisbah Zon Bahagian Terbakar (PBZR) sebanyak 2:8, 3:7, 4:6, 5:5, 6:4, 7:3 dan 8:2. Nisbah dua persamaan, setiap satu bahan api MFB adalah (?1, ?2), (0.8, 0.6) dan (0.6, 0.8) dan diuji menggunakan pelbagai peratus bahan api campuran. Nilai perbandingan bagi tiga kes zon dibuat menggunakan nilai puncak dari model tiga-zon bagi menilai model empat-zon. Model ini dibandingkan dengan enjin cucuhan bunga api (SIE) beroperasi dengan motor alkohol premium (PMS) sebagai garis asas. Keadaan operasi enjin adalah dihadkan pada 2000 rpm kelajuan enjin, masa pencucuhan -35bTDC dan tempoh pembakaran pada 60 oC. Tekanan berkesan min tertunjuk (IMEP), kecekapan haba tertunjuk (?), tekanan silinder dan pecahan pengeluaran dari model yang dibangunkan dan analisis dua-zon yang terhasil adalah sama dengan nilai literatur. Dapatan kajian menunjukkan cas terbakar pada isipadu yang banyak adalah tidak diingini sebagai penyerap. Model tiga bahagian zon menunjukkan kecekapan haba enjin tertinggi dan tekanan puncak pada jisim bakar dengan nisbah 7:3. Manakala, pengurangan umum telah diperhatikan pada pengeluaran N2 di peralihan tiga-zon dan model empat zon