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STUDY OF LIQUID-LIQUID SLUG BREAK UP MECHANISM IN A MICROCHANNEL T-JUNCTION AT VARIOUS MODIFIED WEBER NUMBER
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The formation of immiscible liquid droplets, or slugs, in microchannels features the advantages of volume control and mixing enhancement over single-phase microflows. Although the applications of droplet-based microfluidics have been widely demonstrated, the fundamental physics governing droplet break-up remains an area of active research. This study defines an effective Weber (Weeff) number that characterizes the interplay of interfacial tension, shear stress and channel pressure drop in driving slug formation in T-junction microchannel for a relative range of low, intermediate and high flow rates. The immiscible fluid system in this study consists of Tetradecane slug formation in Acetonitrile. The progressive deformation of slug interfaces during break-up events is observed. Experimental results indicate that, at a relatively low Weeff, clean slug break-up occurs at the intersection of the side and main channels. At intermediate Weeff, the connecting neck of the dispersed phase is stretched to a short and thin trail of laminar flow prior to breaking up a short distance downstream of the T-junction. At a relatively high Weeff, the connecting neck develops into a longer and thicker trail of laminar flow that breaks up further downstream of the main channel
THE EFFECT OF FIBER CONTENT ON COTTON REINFORCED ALBUMEN COMPOSITES
No full textABSTRACT : The effect of fiber content on mechanical properties and thermal stability of the cotton/albumen composites (CAC) were investigated and presented in this paper. The composites having 0%, 3%, 6%, 10%, 13 %, and 16% w/w of cotton fiber were considered. Â Hands lay-up technique was used to prepare the CAC specimens and dried for 24 hours before characterised and evaluated for their mechanical performance. The structure and thermal stability of the composites were characterized by using x-ray and thermogravimetry analysis, respectively. The tensile strength and impact resistance of CAC are found maximum with the value of 8.7 MPa and 19.0 kJ/m2, respectively. Analysis on the morphological structure by SEM revealed that the mechanical properties of the composites depend on good wettability and adhesion between fiber/matrix
Automatic Extraction of Ferromagnetic Particle from Non-homogeneous Solid-Solid Mixture
Get PDFSeparation of magnetic particles in sand processing is very important for many industrial purposes. This paper presents an automation process to separate the magnetic particles from a non-homogeneous solid-solid mixture (sea sand). Here a magnetic force is created by changing the electric field and thus the particles are separated from the mixture of sand automatically. Here such a simple and cost effective design is prsented which can automatically take the the mixture as input and give the refined and separated product as output continuously. ABSTRAK : Pengasingan zarah-zarah bermagnet dalam pemprosesan pasir penting untuk pelbagai tujuan industri. Kertas ini membentangkan proses pengautomatikan untuk mengasingkan butir-butir bermagnet dari pepejal tak homogen - campuran pepejal (pasir pantai). Di sini, daya magnet dihasilkan dengan menukarkan medan elektrik dan seterusnya butir-butir ini terasing daripada campuran pasir dengan sendirinya. Kaedah yang mudah dan rekaan keberkesanan kos ini secara langsung mengambil campuran tersebut sebagai input dan memberikan hasil bertapis dan terpisah sebagai output dengan berterusan
Comparison of the Production of Recombinant Protein in Suspension Culture of CHO Cells in Spinner Flask and Shake Flask System
Get PDFChinese hamster ovary (CHO) cells have been most widely used as the production host for the commercial production of biopharmaceuticals product. They have been extensively studied and developed, and today provide a stable platform for producing monoclonal antibodies and recombinant proteins. This study was focusing on comparison of suspension culture system by using spinner flask and shake flask for the growth and production of recombinant protein in CHO cell line. The CHO cells were transfected with an expression of DNA plasmid containing lac Z gene which codes for β-galactosidase. The recombinant genes in these CHO cells and the β-galactosidase expressing cells were adapted to suspension culture. The agitation speed for both spinner and shake flask were adjusted accordingly. The experiments were carried out in duplicate and samples were taken for cell count, determination of glucose consumption, lactate production and protein level by using biochemical assay. The result showed that, the cell growth in spinner flask is more favorable then in shake flask. The cell concentration in spinner flask is 58% higher than in shake flask. On the other hand, specific activity of β-galactosidase is 25% higher in spinner flask compared to shake flask, at the same agitation speed.ABSTRAK: Sel ovari hamster China (Chinese hamster ovary (CHO)) digunakan secara meluas dalam hos pembiakan untuk tujuan komersil produk biofarmaseutikal. Ia telah dikaji dan dibangunkan secara ekstensif, dan kini ia menyediakan landasan yang stabil untuk penghasilan antibodi monoklon dan protein rekombinan. Kajian ini memfokuskan tentang penghasilan protein rekombinan menggunakan kultur ampaian sel CHO di dalam kelalang putar dan kelalang goncang. Sel CHO dimasukkan dengan plasmid DNA yang mengandungi gen lac Z yang juga memberikan kod untuk β-galaktosidase. Sel CHO β-galaktosidase-terungkap dimasukkan ke dalam kultur ampaian. Kelajuan agitasi untuk kedua-dua kelalang putar dan kelalang goncang disesuaikan dengan sewajarnya. Eksperimen dijalankan menggunakan pendua dan sampel yang diambil untuk kiraan sel, penentuan penggunaan glukosa, penghasilan laktat dan aras protein dengan menggunakan cerakin biokimia. Keputusan menunjukkan tumbesaran sel di dalam kelalang putar lebih menggalakkan daripada dalam kelalang goncang. Kepekatan sel dalam kelalang putar adalah 58% lebih tinggi daripada dalam kelalang goncang. Sebaliknya, pada kelajuan agitasi yang sama, aktiviti tertentu β-galaktosidase adalah 25% lebih tinggi dalam kelalang putar dibandingkan dengan kelalang goncang
Effect of Rhizopus oryzae Fermentation on Kenaf-Based Polylactic Acid’s Monomer
Get PDFKenaf biomass is the potential as raw materials used to produce polylactic acid's monomer which is lactic acid via fermentation by Rhizopus oryzae. Kenaf biomass' structure is complex due to its lignin and cellulose content. This matter had encouraged it to undergo pre- treatment process as the initial step before fermentation process can be done. In this paper, kenaf biomass was treated with dilute sulphuric acid (H2SO4) to hydrolyze the cellulose content in it as well as to convert the cellulose into glucose- a carbon source for Rhizopus to grow. Then, the fermentation process was carried out in shake flask for 3 days at pH 6. Several conditions for fermentation process had been chosen which were 25oC at 150 rpm, 25 oC at 200 rpm, 37 oC at 150 rpm and 37oC at 200 rpm. In this fermentation process, 0.471 g/L, 0.428 g/L, 0.444 g/L and 0.38 g/L of lactic acid was produced respectively. Sample at 25oC at 200 rpm produced maximum amount of lactic acid compared to others.ABSTRAK: Biojisim kenaf berpotensi sebagai bahan mentah dalam penghasilan monomer asid polylactic (poliester alifatik termoplastik diterbitkan daripada sumber boleh diperbaharu seperti kanji jagung) yang merupakan asid laktik menerusi penapaian oleh Rhizopus oryzae (sejenis fungus yang hidup dalam jirim organik yang telah mati). Struktur biojisim kenaf adalah kompleks disebabkan kandungan lignin dan selulosanya. Hal ini menyebabkan ia perlu melalui proses pra-rawatan sebagai langkah awal sebelum proses penapaian dijalankan. Dalam kertas ini, biojirim kenaf dirawat dengan asid sulfurik (H2SO4) yang dicairkan untuk menghidrolisis kandungan selulosa di dalamnya di samping menukar selulosa menjadi glukosa - sumber karbon bagi tumbesaran Rhizopus. Kemudian, proses penapaian dijalankan di dalam kelalang goncang selama 3 hari pada pH 6. Beberapa ciri proses penapaian telah dipilih iaitu 25 oC pada 150 rpm, 25 oC pada 200 rpm, 37 oC pada 150 rpm dan 37 oC pada 200 rpm. Dalam proses penapaian ini, 0.471 g/L, 0.428 g/L, 0.444 g/L dan 0.38 g/L asid laktik dihasilkan secara berturut. Sampel pada 25oC pada 200 rpm menghasilkan kadar asid laktik yang maksimum dibandingkan dengan yang lainnya.KEY WORDS :Kenaf biomass, pre-treatment, lactic acid, Rhizopus oryzae, fermentatio
Determination of IGF-1-Producing CHO-K1 Growth Phases Using GCMS-Based Global Metabolite Analysis
Get PDFMammalian cell lines, in particular CHO-K1 is vital for the multibillion dollar biotechnology industry. The majority of large scale bioprocessing of commercially valuable protein biopharmaceuticals is produced using this type of cell. An ideal mammalian cell system as host for biologics production should retain efficient use of energy sources in order to boost productivity at minimum cost. Various analyses such as cell counting and monitoring of specific biochemical responses are used to provide data to enable bioprocess control in order to achieve the ideal system. Our study aimed to see whether global metabolite analysis using Gas Chromatography Mass Spectrometry (GCMS) would be a potential alternative approach in providing data for bioprocess control. In this study, we analyzed metabolites of CHO-K1 cells at different growth phases using GCMS. CHO-K1 cells producing insulin like growth factor-I (IGF1) were obtained from ATCC. Cells were grown in T-flask and incubated at 37°C/ 5% CO2 until 70-80% confluent in RPMI 1640 media. Samples (cells and spent/conditioned media) were taken at designated intervals for routine cell counting (Trypan Blue dye exclusion method); glucose, glutamine and lactate determination (YSI 2700); IGF-1 production (ELISA kit R&D Sstems, Inc); and global metabolite analysis (GCMS). Conditioned media from each time point were spun down before subjecting into GCMS. Data from GCMS was then transferred to SIMCA P+12.0 for chemometric evaluation using Principal Component Analysis (PCA). The first component, PC1 results was able to explain 36% of the variation of the data with clear separation between exponential phase and other phases (initial and death phase). This suggests that GCMS-based global metabolite analysis has the ability to capture cell growth behaviour and offered insights of factors that may influence the biological system.ABSTRAK: Produk yang berupa sel kekal mamalia, terutamnya CHO-K1 adalah penting dan menguntungkan industri bioteknologi. Majoritinya pemprosesan protein biofarmaseutikal secara besar-besaran dihasilkan dengan menggunakan sel jenis ini. Sistem sel mamalia yang ideal sebagai hos untuk penghasilan produk ubatan harus mengekalkan penggunaan sumber tenaga secara efisien untuk meningkatkan produktiviti pada kos yang minima. Pelbagai analisa seperti penghitungan sel dan pemerhatian tindak balas biokimia tertentu digunakan untuk memberikan data dan untuk menentukan bioproses terkawal untuk mendapat sistem yang ideal. Kajian ini dijalankan untuk mengkaji sama ada analisa metabolit global menggunakan Spektrometri Jisim Kromatografi Gas (Gas Chromatography Mass Spectrometry (GCMS)) boleh berpotensi sebagai pendekatan alternatif dalam membekalkan data untuk kawalan bioproses. Dalam kajian ini, metabolit sel CHO-K1 dikaji pada peringkat tumbesaran berbeza menggunakan GCMS. Sel CHO-K1 menghasilkan insulin seperti faktor pertumbuhan-I (IGF1) didapati daripada ATCC. Sel dibesarkan dalam kelalang-T dan dieramkan pada 37°C/ 5% CO2 sehingga 70-80% konfluen dalam perantara RPMI 1640. Sampel (sel dan perantara yang digunakan/dilazimkan) diambil kiraan pada selang masa yang telah ditetapkan untuk sel rutin (kaedah eksklusi pencelup Trypan Blue), glukosa, glutamin dan penentuan laktat (YSI 2700); penghasilan IGF -1 (kit ELISA R&D Sstems, Inc); dan analisa global metabolit (GCMS). Perantara yang dilazimkan dari setiap poin masa dikurangkan kelajuannya pada setiap pusingan sebelum dianalisa secara GCMS. Data daripada GCMS kemudiannya dipindahkan ke SIMCA P+12.0 untuk taksiran kemometrik menggunakan Analisis Komponen Utama (Principal Component Analysis (PCA)). Keputusan komponen pertama, PC1 berupaya menjelaskan variasi 36% data dengan pengasingan jelas antara fasa eksponen dan fasa-fasa lain (fasa permulaan dan fasa akhir). Ini menunjukkan bahawa analisa metabolit global berasaskan GCMS mampu menjelaskan tingkah laku pertumbuhan sel dan memberikan pemahaman tentang faktor-faktor yang mempengaruhi sistem biologikal.KEY WORDS: CHO-K1 cells, IGF-1, metabolomics, metabolite profile, PCA, GCMS
Zinc-Laccase Biofuel Cell
Get PDFA zinc-laccase biofuel cell adapting the zinc-air cell design features is investigated. A simple cell design configuration is employed: a membraneless single chamber and a freely suspended laccase in a quasi-neutral buffer electrolyte. The cell is characterised according to its open-circuit voltage, polarization profile, power density plot and discharge capacity at constant current. The biocatalytic role of laccase is evident from the polarization profile and power output plot. Performance comparison between a single chamber and dual chamber cell design is also presented. The biofuel cell possessed an open-circuit voltage of 1.2 V and delivered a maximum power density of 0.9 mW/cm2 at current density of 2.5 mA/cm2. These characteristics are comparable to biofuel cell utilising a much more complex system design.KEY WORDS (keyword)): Biofuel cell, Bioelectrochemical cell, Zinc anode, Laccase and Oxidoreductase.ABSTRAK: Sel bio-bahan api zink-laccase dengan adaptasi daripada ciri-ciri rekabentuk sel zink-udara telah dikaji. Sel dengan konfigurasi rekabentuk yang mudah digunapakai: ruangan tunggal tanpa membran dan laccase diampaikan secara bebas di dalam elektrolit pemampan quasi-neutral. Sel dicirikan berdasarkan voltan litar terbuka, profil polarisasi, plot ketumpatan kuasa dan kapasiti discas pada arus malar. Peranan laccase sebagai bio-pemangkin adalah amat ketara daripada profil polarisasi dan plot ketumpatan kuasa. Perbandingan prestasi di antara sel dengan rekabentuk ruangan tunggal and dwi-ruangan turut diketengahkan. Seperti dijangkakan, sel dengan rekabentuk ruangan tunggal menunjukkan kuasa keluaran yang lebih rendah jika dibandingkan dengan rekabentuk dwi-ruangan kemungkinan disebabkan fenomena cas bocor. Sel bio-bahan api ini mempunyai voltan litar terbuka 1.2 V dan memberikan ketumpatan kuasa maksima 0.9 mW/cm2 pada ketumpatan arus 2.5 mA/cm2. Ciri-ciri ini adalah sebanding dengan sel bio-bahan api yang menggunapakai rekabentuk sel yang jauh lebih rumit
Over Expression of Voltage Dependent Anion Channel 2 (VDAC2) in Muscles of Electrically Stunned Chickens
Get PDFWater bath stunning is a common practice in commercial slaughterhouses. Such treatment is economic and in line with animal welfare practice. However, the conditions applied for the stunning process may vary from a slaughterhouse to another slaughterhouse. Such a loose regulation on the stunning procedure has opened up doors for food adulteration such as over dose stunning. In this study, a simple and reliable approach using proteomics have been developed to study the effect of different currents and voltages in stunning on the protein expression of the chickens. Protein profiles of the chickens were constructed in order to detect any differences in protein expression and modifications. The different voltage studied were 10 V, 40 V and 70 V while the values for current studied were 0.25 A, 0.5 A, and 0.75 A. After the proteomics analyses using 2D Platinum ImageMaster 6.0 and Matrix-assisted laser desorption ionization- time of flight (MALDI TOF) spectrometry identification, Voltage dependent anion channel 2 (VDAC2) was identified to be over expressed in the muscle sample of over stunned chicken. The over expression of VDAC2 was confirmed at the transcriptional level of RNA expression. Real Time PCR showed that all over stunned samples contained higher mRNA expression level for VDAC2 genes. The mRNA level of VDAC2 was up-regulated by 59.87 fold change when normalized with housekeeping gene. In conclusion, VDAC2 could serve as potential biomarkers for identification of electrically stimulated chickens. The existence of these biomarkers will help to monitor the slaughtering and stunning process in the future. It will revolutionize the food authentication field and give a new breathe to the meat industry.ABSTRAK: Kaedah "waterbath stunning" merupakan amalan biasa di pusat-pusat penyembelihan. Kaedah ini adalah ekonomik dan selari dengan amalan kebajikan haiwan. Walaubagaimanapun, syarat-syarat yang digunakan untuk proses kejutan tersebut mungkin berbeza antara sebuah pusat sembelihan dengan pusat sembelihan yang lain. Sebarang peraturan yang longgar semasa proses kejutan tersebut membuka ruang kepada adulterasi makanan seperti lebihan dos kejutan elektrik. Dalam kajian ini, satu pendekatan yang mudah dan boleh dipercayai menggunakan proteomik telah dibangunkan untuk mengkaji kesan arus dan voltan yang berbeza dalam proses kejutan elektrik terhadap ekspresi protin di dalam ayam. Profil protein ayam telah dibuat untuk mengesan sebarang perbezaan terhadap ekspresi dan modifikasi protin. Nilai voltan berbeza yang dikaji ialah 10 V, 40 V dan 70 V manakala nilai arus yang dikaji 0.25 A, 0.5 A, dan 0.75 A. Selepas analisis proteomik menggunakan Platinum 2D ImageMaster 6.0 dan Matrix-Assisted Laser Desorption Ionization-Time of Flight (MALDI TOF) Spectrometry Identification, Voltage Dependent Anion Channel 2 (VDAC2) dikenal pasti terlebih ekspres di dalam sampel otot ayam yang terlebih dos kejutan elektrik. Lebihan ekspresi VDAC2 disahkan di peringkat transkripsi ekspresi RNA. Real Time PCR menunjukkan bahawa kesemua sampel yang terlebih dos kejutan mengandungi tahap ekspresi mRNA yang lebih tinggi di dalam gen VDAC2. Tahap mRNA VDAC2 dikawal oleh 59.87 perubahan kali ganda apabila dinormalkan dengan gen housekeeping. Kesimpulannya, VDAC2 boleh bertindak sebagai penanda biologi yang berpotensi untuk mengenal pasti ayam yang dirangsang elektrik. Kewujudan penanda biologi ini akan membantu memantau proses penyembelihan dan kejutan pada masa akan datang. Ia akan merevolusikan bidang pengesahan makanan dan memberi nafas baru kepada industri daging.KeywordsStunning, Slaughtering, Proteomics, Voltage dependent anion channel 2, Chicken muscl
SURFACTANT-POLYMER FLOODING PERFORMANCE IN HETEROGENEOUS TWO-LAYERED POROUS MEDIA
Get PDFIn this paper, simulation study was conducted to investigate the effect of spatial heterogeneity of multiple porosity fields on oil recovery, residual oil and microemulsion saturation. The generated porosity fields were applied into UTCHEM for simulating surfactant-polymer flooding in heterogeneous two-layered porous media. From the analysis, surfactant-polymer flooding was more sensitive than water flooding to the spatial distribution of multiple porosity fields. Residual oil saturation in upper and lower layers after water and polymer flooding was about the same with the reservoir heterogeneity. On the other hand, residual oil saturation in the two layers after surfactant-polymer flooding became more unequal as surfactant concentration increased. Surfactant-polymer flooding had higher oil recovery than water and polymer flooding within the range studied. The variation of oil recovery due to the reservoir heterogeneity was under 9.2%
DESIGN AND FABRICATION OF MICRONOZZLES
Get PDFMicronozzle, a key component in micropropulsion system, has been designed and fabricated. Quasi 1D inviscid theory was used in designing a series of conical micronozzles of different expander half-angles (10°-50°). Aerospike micronozzle, a promising candidate to achieve high performance propulsion system, was designed with Angelino method (or Approximate method). Both micronozzles were fabricated using soft lithography, an inexpensive and relatively simple technique comparing to well-established deep reactive ion etching (DRIE) technique, with polydimethylsiloxane (PDMS) as structural material. Micronozzles with two different nozzle throat width, 53.5µm and 107µm, were fabricated for comparison. Microscopic inspections reveal 107µm is the more producible nozzle throat width with current equipments. The PDMS-based micronozzle can be used as cold gas microthruster system for micro- and nanosatellites