The Effect of Alumina and Magnesia Supported Germanium Nanoparticles on the Growth of Carbon Nanotubes in the Chemical Vapor Deposition Method

The effect of alumina and magnesia supported germanium (Ge) nanoparticles on the synthesis of carbon nanotubes (CNTs) using the chemical vapor deposition (CVD) method in atmospheric pressure was investigated. The TEM micrographs confirmed the formation of carbon nanotubes, and the field emission scanning electron microscopy (FESEM) analysis suggested a tip-growth mechanism for the grown carbon nanotubes. The X-ray diffraction (XRD) pattern indicated a graphitic nature of the carbon nanotubes. The obtained CNTs using Ge nanoparticles supported by MgO resulted in a higher degree of graphitization than the CNTs obtained using Ge nanoparticles supported by Al2O3. Raman spectroscopy analysis of the CNTs confirmed the presence of radial breathing modes (RBM), which verified the formation of CNTs. High frequency Raman analysis demonstrated that the degree of graphitization of the synthesized CNTs using magnesia supported Ge nanoparticles is higher than that of the alumina supported Ge nanoparticles with the values of (ID/IG) ratios equal to 0.45 and 0.73, respectively

Combination of gamma irradiation and sodium carbonate pretreatment on oil palm Empty Fruit Bunch (EFB) for high acidic hydrolysis yield

Oil palm empty fruit bunch (EFB) fibres were pretreated by gamma irradiation followed by sodium carbonate (Na2CO3) before the acid hydrolysis process to produce reducing sugars using diluted sulphuric acid (H2SO4). In this study, EFB fibres were irradiated at different doses, i.e. 0, 100 and 200 kGy. Meanwhile, the gamma irradiated sample were then subjected to Na2CO3 pretreatment with 0 and 5% total titratable alkali (TTA). The effect of the pretreatment using gamma irradiation and Na2CO3 on the physical and chemical properties of the EFB fibres and the yield of the reducing sugar obtained from the acid hydrolysis process was investigated. The obtained results showed that the content of holocellulose was increased significantly with the increase of irradiation doses combined with Na2CO3 pretreatment, whereas lignin content of the EFB was decreased. The gamma irradiation and Na2CO3 pretreatment resulted in structure breakage and removal of silica of EFB fibres which can be due to the swelling of the fibres. A synergistic effect between gamma irradiation and Na2CO3 was observed, in which the yield of reducing sugars was increased by combining the gamma irradiation and Na2CO3 pretreatment

Au/TiO 2

Nanogold doped TiO2 catalysts are synthesized, and their application in the photodegradation of dye pollutants is studied. The materials are characterized using different analytical techniques such as X-ray diffraction, transmission electron microscopy, UV-visible diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy. The results revealed the strong interaction between the metallic gold nanoparticles and the anatase TiO2 support. Au doped systems showed very good photoactivity in the degradation of dye pollutants under UV irradiation as well as in sunlight. A simple mechanism is proposed for explaining the excellent photoactivity of the systems. The reusability studies of the photocatalysts exhibited more than 98% degradation of the dye even after 10 repeated cycles

Enhancement in Monitoring for Integrated Project Implementation

AbstractIntegrated project for Year III has been introduced by the Department of Chemical and Process Engineering since 2007/2008 session. This project integrates three or four compulsory subject for each semester. The purpose of this project was to minimize student work load and help student to understand how each courses are related. Project monitoring is one of the procedures to evaluate the performance of integrated project. Since implementation of this project, the coordinator of integrated project will give feedbacks to the students on their performance after they have completed presenting their project. Even though this method is quite sufficient for student to learn their mistake unfortunately similar mistakes was repeated during their final year design project in final year. In order to overcome this problem, student self-assessment for integrated project was introduced during Semester II, Session 2011/2012. The results show that the students were able to detect their mistakes and errors, and some correction was done to their project

Preparation of carbon nanotubes via chemical technique (modified Staudenmaier method)

The chemical method is one of the most promising routes for the production of multi-walled carbon nanotubes. In this study, multi-walled carbon nanotubes (MWCNTs) were successfully synthesized by the modified Staudenmaier method. MWCNTs were synthesized using graphite powder at room temperature. This process does not utilize any metal catalyst. The prepared multi-walled carbon nanotubes were characterized for their crystalline, structural and thermal stability properties. The structural, crystalline and morphological characterization of The produced MWCNTs were performed by using scanning electron microscopy(SEM), transmission electron microscopy(TEM), X-ray diffraction (XRD), thermogravimetric analysis(TGA), Raman analysis, and atomic force microscopy( AFM). Crystallinity and graphitization degree was observed for the produced MWCNTs have a diameter of 13.1 nm. The yield is approximately 10% of the carbon source (graphite). Moreover, the obtained MWCNTs have high thermal stability and oxidation resistance lower than 401.80 °C. The present approach provides a simple low cost and easy method of MWCNTs synthesis

Mekanisme Penyerakan Zarah Dalam Pemprosesan Berkoloid Oksida Seramik (Al2o3-Zro2-Mgo) Menggunakan Daxad 19tm

Dalam Kajian Ini, Kesan Agen Penyerak Komersil Daxad 19TM Terhadap Sifat Reologi Dan Pemadatan Ampaian Seramik Alumina-Zirkonia-Magnesia Telah Dikenalpasti. Komposisi Serbuk Yang Digunakan Adalah Berasaskan Kepada 85% Isipadu Alumina (Ketulenan 99.99%) Dan 15% Isipadu Zirkonia (Ketulenan 99.5%). Penambahan Serbuk Magnesia (Ketulenan 99.99%) Pula Adalah Pada Kuantiti Yang Kecil Iaitu 0.25% Berat Dari Pada Jumlah Berat Alumina Dan Zirkonia. Untuk Mengelakkan Masalah Pengaglomeratan Zarah, Teknik Pemprosesan Berkoloid Dipilih Dalam Pembikinan Sampel. Untuk Ini, Daxad 19TM Dicampurkan Ke Dalam Ampaian Dengan Tujuan Untuk Menyerakkan Zarah Kuantiti Penyerak Daxad 19TM Yang Digunakan Ialah Dalam Julat 0 Hingga 0.60% Berat. Kajian Reologi Menggunakan Alat Meter Kelikatan Dilakukan Bagi Mengenalpasti Kuantiti Daxad 19TM Yang Optimum Bagi Penyerakan Zarah. Setelah Itu, Sampel Anum Dihasilkan Melalui Proses Penuangan Buburan. Sampel Diprasinter Pada Suhu 800°C Selama 45 Minit Sebelum Disinter Pada Suhu 1600°C Selama 2 Jam. Kajian Ini Secara Keseluruhannya Telah Mendapati Julat Penggunaan Optimum Penyerak Daxad 19TM Di Dalam Ampaian Seramik Yang Dihasilkan Adalah Di Antara 0.4875% Hingga 0.525% Berat Daripada Berat Keseluruhan Serbuk Seramik Yang Digunakan. Kertas Ini Juga Membincangkan Mekanisme Penyerakan Zarah Dalam Ampaian Alumina-Zirkonia-Magnesia Melalui Penggunaan Daxad 19TM

Experimental investigation on fluidized bed jet grinding

Fluidized bed jet grinding is a well accepted method for producing powders with an average particle size of less than 10 μm quickly and effectively. Its use has increased steadily for grinding chemicals, minerals, pigments, pharmaceuticals, abrasives, plastics and food. Nevertheless, even though the uses are increasing, the basic mechanism of comminution within such mill is not well understood and their design and prediction of performance is therefore largely very empirical. Using coarse cracking catalyst and 2 mm i.d. jet nozzles, the effects of gas mass flowrate, separation distances and geometry of the set up on the initial grinding rate have been investigated. It was found that grinding was a consequence both of interparticle collisions in the jet region, and when a target plate was used, of abrasion on the single plate. For a given power input, target plate jet grinding gave a higher production rate and finer size of product than with two opposing nozzle

Pemisahan zarah mengguna teknik ayak: Kesan parameter pengoperasian ke atas kecekapan

Separation of solid mixtures of different particle sizes into two size grades by means of a screening surface is widely used. For thousands of years the fundamental principle of screening has been and still is maintained. Despite of the advantages such as easy operation and low cost of maintenance, the overall efficiency of the process is of importance for optimization purposes. In this case, investigation on the effect of several operating parameters such as time, vibration frequency, percentage of coarse (oversize) in the feed material and total loading on the overall efficiency of the separation process has been carried out using solid mixtures of sand and glass beads. A general form of empirical correlation has been obtained, from which suitable operation conditions for optimum process efficiency may be determine