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Effect of Spray Drying on Protein Content of Natural Rubber Serum (NRS)
Get PDFNatural rubber latex comprises approximately 70% natural rubber serum (NRS) which is the aqueous part of the latex. The NRS is made up of mainly water and non-rubber components; sugar, protein and other lipids. The protein component of the NRS is separated using membrane separation and spray dried whereby the amino acid and protein content was monitored during the process. The optimum drying temperatures were first determined to obtain the maximum recovery of the protein powder, whereby the amino acid content was approximately 40 times that of the feed. The production of protein powder from NRS increases the rubber industry's competitiveness through value addition to the previously discarded NRS but also to the processing industry. NRS protein powder has a great opportunity to be developed as an alternative protein source.ABSTRAK: Susu getah asli mengandungi lebih kurang 70% serum getah asli (natural rubber serum (NRS)) iaitu bahagian susu getah yang berair. NRS sebahagian besarnya merupakan air dan komponen bukan getah; gula, protein dan lipid-lipid lain. Komponen protein NRS dipisahkan dengan menggunakan membran pemisah dan kaedah kering semburan dimana asid amino dan kandungan protein dipantau semasa proses tersebut. Pada mulanya, suhu pengeringan optimum ditentukan untuk mendapatkan hasil maksima serbuk protein, dimana kandungan asid amino adalah lebih kurang 40 kali suapan. Penghasilan serbuk protein daripada NRS meningkatkan daya saing industri getah dan industri pemprosesan menerusi pertambahan nilai terhadap NRS yang sebelum ini hanya dibuang. Serbuk protein NRS mempunyai peluang besar untuk dimajukan sebagai sumber protein alternatif.KEY WORDS: protein, spray dry, natural rubber serum
Micro-Sized Particle Production of Momordicas sp Extract Using Spray Dryer
Get PDFSpray drying is the most widely used industrial process involving particle formation and drying. It is highly suited for the continuous production of dry solids in either powder, granulate or agglomerate form from liquid feed-stocks as solutions, emulsions and pump able suspensions. Therefore, spray drying is an ideal process where the end-product must comply with precise quality standards regarding particle size distribution, residual moisture content, bulk density, and particle shape. In this study, Momordica sp extract product has been successfully spray dried into micro scale of powder particle and will be used as plant-based insulin. The process optimized using Taguchi method with four factors and three levels has given a good quality of the product. The average of particle size was obtained at about 11 microns.ABSTRAK: Kering sembur digunakan secara meluas dalam proses industri yang melibatkan pembentukan zarah dan pengeringan. Ia amat sesuai dalam penghasilan pepejal kering secara beterusan dalam bentuk serbuk, butiran atau gumpalan daripada simpanan suapan bendalir sebagai larutan, emulsi dan ampaian boleh dipam. Maka, kering sembur adalah proses yang ideal apabila hasil akhir harus mematuhi piawaian kualiti yang tepat berkaitan dengan pengagihan saiz zarah, kandungan kelengsaan sisa, ketumpatan pukal dan bentuk zarah. Dalam kajian ini, produk ekstrak Momordica sp (dikenali juga sebagai peria katak) telah berjaya dikering sembur menjadi serbuk zarah berskala mikro dan akan digunakan sebagai insulin berasaskan tumbuhan. Proses ini dioptimumkan dengan pengunaan kaedah Taguchi empat faktor dan tiga peringkat, agar memberikan hasil produk yang berkualiti. Kadar purata saiz zarah yang terhasil adalah lebih kurang 11 mikron.KEY WORDS: micro-sized, particle, Momordica sp, spray dryer
PROCESS SIMULATION AND QUALITY EVALUATION IN INCREMENTAL SHEET FORMING
Get PDFSingle Point Incremental Forming (SPIF) is a promising sheet-metal-forming process that permits the manufacturing of small to medium-sized batches of complex parts at low cost. It allows metal forming to work in the critical ‘necking-to-tearing' zone which results in a strong thinning before failure if the process is well designed. Moreover, the process is complex due to the number of variables involved. Thus, it is not possible to consider that the process has been well assessed; several remaining aspects need to be clarified. The objective of the present paper is to study some of these aspects, namely, the phenomenon of the wall thickness overstretch along depth and the effect of the tool path on the distribution of the wall thickness using finite element simulations.Abstrak: Pembentukan Tokokan Mata Tunggal (Single Point Incremental Forming (SPIF)) merupakan satu proses pembentukan kepingan logam yang membolehkan pembuatan dalam jumlah yang kecil hingga sederhana, bahagian-bahagian yang kompleks pada kos yang rendah. Jika proses ini direka dengan baik, kaedah ini membolehkan pembentukan logam yang baik terhasil. Jika tidak, semasa peringkat zon kritikal ‘perleheran-ke-pengoyakan' menyebabkan penipisan keterlaluan yang boleh menyebabkan logam tersebut rosak. Tambahan pula, proses ini agak kompleks, kerana ia melibatkan beberapa pemboleh ubah. Maka, walaupun proses ini telah dinilaikan seeloknya; masih terdapat beberapa aspek lain yang perlu diperjelaskan. Objektif kertas ini dibentangkan adalah untuk mengkaji beberapa aspek tertentu, seperti, ketebalan dinding regangan berlebihan di sepanjang kedalaman dan kesan tool path (beberapa siri posisi koordinat untuk menentukan pergerakan alatan memotong ketika operasi memesin) terhadap pengagihan ketebalan dinding menggunakan simulasi unsur terhingga
NUMERICAL INVESTIGATION OF CHOCKED CONVERGING-DIVERGING NOZZLES FOR THRUSTER APPLICATION
Get PDFThe need for low-thrust propulsion systems for small scale spacecraft is growing. Low thrust characteristics generally lead to low Reynolds number flows from propulsive devices that utilize converging-diverging nozzle. In the present work, seven choked converging-diverging nozzle flow characteristics operating at Reynolds number of 46000 are numerically investigated using a commercial software FLUENT 6.1.22. Computational work is carried out using axisymmetric flow Spalart-Allmaras model, two-dimensional, axisymmetric, coupled solver and linearized using implicit scheme. The nozzles, which are intended to be used for thruster application, have a throat diameter of 11 mm and an area ratio of 4. All six nozzles are derived from a nozzle with divergence angle of 28°, where the divergence angle is reduced while maintaining the area ratio. The main objective of this work is to investigate the performance and flow characteristic of nozzles with different geometry. Numerical findings show that there is thrust reduction observed as the divergence angle reduces from 28° to 10°, except for nozzle with divergence angles of 16° and 18°, where they produce thrusts higher than their derivative one. Numerical result also reveals that the flow separation phenomenon occurs inside all nozzles, where normal shock forms inside nozzles with divergence angle of 20°, 14° and 10°, and this shock degrades the performance of the nozzle in term of the thrust produced.ABSTRAK : Keperluan sistem kuasa kipas tujahan rendah bagi pesawat angkasa berskala kecil makin meningkat. Umumnya ciri-ciri tujahan rendah membawa kepada aliran nombor Reynolds yang rendah dari alat dorongan yang menggunakan muncung tumpu-capah. Buat masa ini, tujuh muncung cekik tumpu-capah beroperasi pada nombor Reynolds 46000 telah dikaji menggunakan perisian komersil FLUENT 6.1.22. Kerja pengiraan dijalankan dengan menggunakan model aliran simetri sepaksi Spalart-Allmaras, dua dimensi, simestri sepaksi, penyelesai terganding dan dilinearkan menggunakan skim tersirat. Muncung tersebut, yang tujuannya adalah untuk digunakan dalam aplikasi penujah, mempunyai lubang berdiameter 11 mm dan bernisbah luas 4. Kesemua enam muncung diterbitkan daripada satu muncung dengan sudut capahan 28°, dimana sudut capahan telah dikurangkan sementara nisbah keluasan dikekalkan. Tujuan utama penyelidikan ini adalah untuk mengkaji prestasi dan ciri aliran muncung yang berbeza geometri. Hasil kajian menunjukkan bahawa kuasa tujahan menurun apabila sudut capahan dikurangan dari 28° ke 10°, kecuali muncung bersudut capahan 16° dan 18°, yang menghasilkan kuasa tujahan lebih tinggi berbanding muncung-muncung terbitan yang lain. Keputusan berangka juga menunjukkan bahawa fenomena pemisahan aliran berlaku di dalam kesemua muncung, dimana kejutan normal terjadi di dalam muncung dengan sudut capahan 20°, 14° dan 10°, dan kejutan ini mengurangkan prestasi muncung tersebut dari segi kuasa tujahan yang dihasilkan
Utilizing of 1-Hexyl-1-Methyl-Pyrrolidinium Bis (Trifluoromethyl-Sulfonyl) Imide as Medium for Electrochemical Generation of Superoxide Ion-Radical
Get PDFThe superoxide ion-radical was generated and analysed electrochemically using cyclic voltammetry (CV) technique from oxygen dissolved in a room-temperature ionic liquid, 1-Hexyl-1-methyl-pyrrolidinium bis (trifluoromethylsulfonyl) imide, at atmospheric pressure. It was found that the generated superoxide ion was stable which indicates its possible use for further useful applications.ABSTRAK: Ion radikal superoksida dihasil dan dianalisa secara elektrokimia menggunakan teknik voltammetri berkitar (cyclic voltammetry (CV)) daripada oksigen yang dilarutkan dalam larutan ionik pada suhu bilik, 1-Hexyl-1-methyl-pyrrolidinium bis (trifluoromethylsulfonyl) imida, pada tekanan atmosfera. Didapati bahawa ion superoksida yang terhasil adalah stabil. Ini menunjukkan ia berkemungkinan berguna dalam aplikasi lain
EVALUATING A SEGMENTATION-RESISTANT CAPTCHA INSPIRED BY THE HUMAN VISUAL SYSTEM MODEL
No full textVisual CAPTCHAs are widely used these days on the Internet as a means of distinguishing between humans and computers. They help protect servers from being flooded by requests from malicious scripts. However, they are not very secure. Numerous image processing algorithms are able to discern the characters used in the CAPTCHAs. It has been suggested that CAPTCHAs can be made more secure if they are distorted in ways that makes segmentation difficult. However, out of all the reviewed distortions present in current CAPTCHAs there are none that allow for a high level of segmentation difficulty. Furthermore, CAPTCHAs also need to be used by humans who may not find certain distortions tolerable. Thus, the problem of selecting a good distortion becomes a tradeoff between user acceptability and computer solvability. It is hypothesized in this paper that rather than use low-level image distortions, optical distortions based on the Gestalt laws of perception that govern human visual system models should be applied. These distortions would ensure widespread user acceptability (as they are based on the internal workings of the HVS), and be very difficult for computers to solve (as HVS perception models have been difficult to implement in computers). This paper aims to explore the feasibility of employing Gestalt-inspired distortion in CAPTCHAs by first implementing a CAPTCHA cracker and then evaluating the performance of some manually generated Gestalt CAPTCHA’s against some existing CAPTCHAs
INVESTIGATION OF THERMAL PERFORMANCE OF AIR TO WATER HEAT EXCHANGER USING NANO-FLUIDS
Get PDFIn the present study the three-dimensional numerical simulation is selected as a tool to investigate the effectiveness of a cross flow heat exchanger. Water is selected to be mixed with nano-particles and flow inside a circular pipe while a pure air is flowing across it. Numerical simulations is carried out under laminar flow for both water and air sides. The thickness of the pipe is neglected in the present preliminary study. From the physics of the problem, the governing parameters can be determined as: the Reynolds, the type and the volume fraction of the nono-fluid. The effect of these governing parameters is studied and the results are presented. The results show significant enhancement of heat transfer with introduction of nano-particles, such as titanium-oxide (TiO2) nano-powder, compared to the pure base fluid. The accuracy of the results presented in the present study depends on the accuracy of the effective properties of the nano-fluids, which are taken from the open literature. ABSTRAK: Dalam kajian ini, simulasi tiga dimensi berangka digunakan untuk mengkaji keberkesanan penukar haba aliran silang. Air dipilih untuk dicampurkan dengan zarah bersaiz nano dan dialirkan di dalam paip berbentuk bulat, sementara udara tulen mengalir melaluinya. Simulasi berangka dijalankan di bawah aliran lamina untuk kedua-dua belah air dan udara. Ketebalan paip diabaikan di dalam kajian permulaan ini. Dari sudut permasalahan fizik, parameter pengawal imbang boleh ditentukan sebagai: nombor Reynolds, jenis dan isipadu pecahan bendalir nano. Kesan parameter pengawal imbang ini dikaji dan keputusannya dibentangkan. Keputusan menunjukkan peningkatan pemindahan haba yang ketara dengan penggunaan zarah bersaiz nano seperti serbuk titanium oksida (TiO2), berbanding dengan bendalir tulen. Ketepatan keputusan kajian ini bergantung kepada ketepatan sifat-sifat efektif bendalir nano yang dirujuk daripada sumber maklumat terdahulu
COMPUTATIONAL INVESTIGATION ON CSF FLOW ANALYSIS IN THE THIRD VENTRICLE AND AQUEDUCT OF SYLVIUS
Get PDFIn this study, a three dimensional (3D) model of the third ventricle and aqueduct of Sylvius derived from MRI scans was constructed by using Computational Fluid Dynamics (CFD) modeling. Cerebrospinal fluid(CSF) can be modeled as a Newtonian Fluid and its flow through the region of interest (ROI) was visualized using Engineering Fluid Dynamics (EFD).The constructed ROI was regarded as rigid walled and only steady state flow was able to be defined due to the limitations of current software. Different flow rate was simulated at the Foramen of Monro and a small stenosis was modeled at the middle of the aqueduct of Sylvius at a fixed location. This was made corresponding to normal patients with variation of CSF flow rate physiologically and abnormal patients with tumor causing obstruction to or within the aqueduct of Sylvius, respectively. Due to the small dimensions of the ROI geometry, gravity and complex external gravity that acted upon it was considered to be neglected. The results show as the flow rate increase, the pressure drop of CSF in the ROI proportionally increased. For normal CSF flow rate, the presence of stenosis in the aqueduct demonstrates a significant increased pressure drop.ABSTRAK-Dalam kajian ini, model tiga dimensi (3D) untuk ventrikel ketiga dan akueduk Sylvius, yang terhasil daripada pengimejan resonans magnetik telah dikonstruksi menggunakan Permodelan Perkomputeran Dinamik Bendalir (Computational Fluid Dynamics (CFD)). Cecair serebrospinal (Cerebrospinal fluid (CSF)) dimodelkan sebagai bendalir Newtonan dan alirannya melalui kawasan kepentingan (region of interest (ROI)) digambarkan menggunakan Dinamik Bendalir Kejuruteraan (Engineering Fluid Dynamics (EFD)). Kawasan kepentingan yang dikonstruksi dianggap sebagai dinding tegar dan hanya aliran keadaan tunak yang dapat ditakrifkan berdasarkan pengehadan perisian komputer terkini. Kadar aliran yang berbeza disimulasikan di foramen monro dan laluan stenosis yang kecil dimodelkan di tengah-tengah akueduk Sylvius di satu lokasi yang telah ditetapkan. Kaedah ini dijalankan terhadap pesakit normal dengan variasi pada kadar aliran CSF, serta pesakit abnormal yang mempunyai tumor, penyebab sekatan terhadap atau melinkungi akueduk Sylvius. Disebabkan oleh ukuran geometri ROI kecil, tarikan graviti dan graviti luar kompleks yang bertindak ke atasnya diabaikan. Keputusan menunjukkan bahawa apabila kadar aliran meningkat, susutan tekanan CSF di dalam ROI meningkat dengan berkadar. Untuk kadar aliran CSF yang normal, kehadiran stenosis di dalam akueduk membuktikan pertambahan susutan tekanan yang ketara
Enhanced Cancer Cell (HeLa) Killing Efficacy of Mixed Αlpha and Gamma Iron Oxide Superparamagnetic Nanoparticles under Combined AC (Alternating Current) Magnetic-Field and Photoexcitation
Get PDFWe synthesized mixed α and γ-Fe2O3 nanoparticles and investigated their toxic effects against HeLa cells under induced AC (alternating current) magnetic-fields and photoexcited conditions at room temperature. The findings revealed that the cell-killing percentage was increased with increasing dose for all types of treatments. Finally, 99% cancer cells were destructed at 1.2 mL dose when exposed to combined AC magnetic-field and photoexcited conditions (T3) whereas 89 and 83 % of HeLa cells were killed under only AC magnetic-field induced (T1) or only photoexcited (T2) condition at the same dose.ABSTRAK: Campuran α dan zarah γ-Fe2O3 bersaiz nano disintesiskan dan kesan toksidnya terhadap sel HeLa dikaji dibawah aruhan medan magnet arus ulang-alik (alternating current (AC)) dan keadaan photoexcited (proses ransangan atom atau molekul suatu bahan dengan penyerapan tenaga sinaran) pada suhu bilik. Penemuan mendedahkan bahawa peratusan sel yang musnah bertambah dengan pertambahan dos untuk semua jenis rawatan. Akhirnya, 99% sel kanser dimusnahkan pada kadar dos 1.2mL setelah didedahkan terhadap kombinasi medan magnet AC dan keadaan photoexcited (T3) dimana 89% dan 83% sel HeLa dimusnahkan dengan hanya di bawah aruhan medan magnet AC (T1) atau hanya pada keadaan photoexcited (T2) pada kadar dos yang sama.KEY WORDS : Cancer, Hyperthermia, Iron oxide nanoparticles, Heat dissipation, Cytotoxicity, HeLa cell
Computer Aided Design of Polygalacturonase II from Aspergillus niger
Get PDFPectin is a complex polysaccharide found in the cell walls of plants and consisting mainly of esterified D-galacturonic acid resides in α-(1-4) chain. In production of fruit juice, pectin contributes to fruit juice viscosity, thereby reducing the juice production and increasing the filtration time. Polygalacturonase improves the juice production process by rapid degradation of pectin. In this project we have designed a novel polygalacturonase enzyme using computer aided design approaches. The three dimension structure of polygalacturonase is first modeled on the basis of the known crystal structure. The active site in this enzyme is identified by manual and automated docking methods. Lamarckian genetic algorithm is used for automated docking and the active site is validated by comparing with existing experimental data. This is followed by in silico mutations of the enzymes and the automated docking process is repeated using the mutant enzymes. The strength of the binding of the ligands inside the active site is evaluated by computing the binding score using Potential Mean Force (PMF) method. The in silico mutations R256Q and K258N are found to decrease the binding strength of the ligand at the active site, indicating lowering of enzyme activity, which is consistent with the experimental results. Hence in silico mutations can be used to design new polygalacturonase enzymes with improved enzyme activity.ABSTRAK: Pektin adalah polisakarida kompleks yang terdapat di dalam dinding sel tumbuhan dan sebahagian besarnya terdiri daripada asid D-galakturonik terester yang ditemui di dalam rantaian α-(1-4). Dalam penghasilan jus buah-buahan, pektin menyumbang dalam kepekatan jus buah-buahan, di mana ia mengurangkan penghasilan jus dan menambahkan masa penapisan. Poligalakturonase meningkatkan proses penghasilan jus dengan pemecahan pektin dengan cepat. Dalam projek ini, kami telah merangka satu enzim poligalakturonase baru dengan menggunakan pendekatan reka bentuk berbantukan komputer. Struktur tiga dimensi poligalakturonase ini pada permulaannya dimodelkan berasaskan kepada struktur kristal. Tapak aktif enzim ini dikenali pasti dengan kaedah mengedok manual dan automatik. Algoritma genetik Lamarckian digunakan untuk dok berautomatik dan tapak aktif ini disahkan dengan perbandingan dengan data eksperimental yang sedia ada. Kaedah ini diikuti pula dengan mutasi in siliko enzim dan proses mengedok automatik diulangi dengan menggunakan enzim mutan. Kekuatan ikatan ligan yang berada di dalam tapak aktif dinilai dengan mengira kiraan ikatan menggunakan kaedah Min Keupayaan Daya (Potential Mean Force (PMF)). Mutasi in siliko R256Q dan K258N merupakan penyebabpenurunan dalam kekuatan ikatan ligan di tapak aktif, menunjukkan pengurangan dalam aktiviti enzim, di mana ianya konsisten dengan keputusan ekperimental. Jesteru, mutasi siliko boleh digunakan untuk mereka enzim poligalakturonase baru dengan mempertingkatkan aktiviti enzim