Formation Of Nanotubular Oxide By Anodization Of Valve Metals

The formation of TiO2 nanotubes (TNTs), ZrO2 nanotubes (ZNTs) and segmented WO3 nanotubes (WNTs) by anodization of Ti, Zr, and W metal was successful in fluorinated aqueous and organic electrolyte. In aqueous electrolyte, acidic 1 M Na2SO4 (pH 3). Glycerol and ethylene glycol were the organic electrolyte with their neutral pH. The properties including morphology and structural of the nanotubular oxide formed were investigated. During anodization, the main factors effecting nanotubular structures are types of electrolyte, its composition, anodization voltage applied to anode and anodization time. It was found that TNTs and ZNTs can be formed in both aqueous and organic electrolytes. However WNTs can only be formed in aqueous electrolyte. The morphology of WNTs also different such that they are not really nanotubular but in a form of segmented porous structure. Both ZNTs and TNTs are highly ordered, well aligned and grow perpendicular to the metal foil. The TNTs formed, had the average diameter ranging from 50-100 nm and length of 700 nm. Detailed analysis of annealing on TNTs reveals that, phase formation to anatase occurred at 350oC at 450oC transformation happened. At temperature > 600oC rutile phase dominated. The mechanism of ZNTs formation is found to be based on three dominating process at the early stage of anodization; anodic ZrO2 formation, pits formation, pore formation followed by pore separation process to form nanotubes. The morphologies of ZNTs can be further classified as double layer, single layer, bundled and precipitates on ZNTs

Midblock U–turn facilities on multilane divided highways: an assessment of driver’s merging gap and stop delays

This paper discusses the results of a study which was carried out with a primary objective to evaluate the merging gaps and traffic delays at midblock U–turn facilities installed on multilane divided highways. A total of more than 2,000 U–turn drivers at a midblock U–turn facility on an urban multilane highway were observed using a camera–video recording technique. The data pertaining to the analysis of gap acceptance and rejection was abstracted from the video–playbacks using a computer event recording program. The analysis found that the critical gap of the drivers at a midblock U–turn facility is in the range of 4.0 – 4.5 seconds, which is different from the values reported for studies carried out in other countries. The effect of major road traffic volumes on the stop delays to the U–turn drivers could not be established because the data did not exhibit any specific trend. The drivers were observed to make forced merging maneuvers when traffic volumes in the main traffic stream are relatively heavy. Such maneuvers lead to flow breakdown in the major road to occur at a faster rate. The findings suggest that there is a need for a thorough study to be carried out to evaluate the current practice of U–turn facility design and assessment methods since traffic operations at such a facility is different from those at on–ramp facilities where their planning and design are generally based on the American Highway Capacity Manual

Effect of voltage on TiO2 nanotubes formation in ethylene glycol solution

The crystalline phase of the TiO2nanotubes without further heat treatment were studied. The TiO2nanotube arrays were produced by anodization of Ti foil at three different voltage; 10, 40, and 60 Vin a bath with electrolytes composed of ethylene glycol (EG), ammonium fluoride (NH4F), and hydrogen peroxide (H2O2). The H2O2is a strong oxidizing agent which was used as oxygen provider to increase the oxidation rate for synthesizing highly ordered and smooth TiO2nanotubes. Anodization at voltage greater than 10 V leads to the formation of tubular structure where higher anodization voltage (~ 60V) yield to larger tube diameter (~ 180 nm). Crystallinity of the nanotubes is improved as the voltage was increased. The transformation of amorphous to anatase can be obtained for as anodized TiO2without any heat treatment. The Raman spectra results show the anodization at 40 V and 60 V gives anatase peak in which confirms the crystalline phase. The stabilization of the crystalline phase is due to the oxygen vacancies and ionic mobilities during the anodization at high voltage

A preliminary study into the effect of oxide chemistry on the bonding mechanism of cold-sprayed titanium dioxide coatings on SUS316 stainless steel substrate

Current attention has focused on the preparation of thick ceramic coating of nano­structured materials as feedstock material using the thermal spray process. The cold spray method has appeared as a promising process to form ceramic nanostructured coating without significantly changing the microstructure of the initial feedstock materials due to its low processing temperature. However, deposition of ceramic powders by cold spray is not easy due to the brittle characteristics of the material. In this study, TiO2 coatings were deposited on unannealed stainless steel substrates and substrates that were annealed from room temperature to 700 °C prior to spraying. The adhesion strength was evaluated to investigate the bonding mechanism. The influence of the remaining surface oxide layer of chromium oxide, Cr2O3, which is thermodynamically preferred for stainless steel, on the bonding mechanism involved was investigated. The results showed that by increasing the annealing substrate temperature of stainless steel, the adhesion strength of the coatings (thicker oxide) is also increased. As a result, the bonding between the cold-sprayed TiO2 particle and the steel substrate is given by the chemical bonding of an inter-oxide reaction

A Facile Coating Method for Superhydrophobic Magnetic Composite Sheet from Biodegradable Durian Peel for Electromagnetic Wave Absorbance Application

Most of the electromagnetic (EM) wave absorbers are commonly made from polymerbased materials. A large number of polymers are resistant to the environmental degradation and are thus responsible for the buildup of polymeric solid waste materials. These solid wastes cause acute environmental problems and remain undegraded for quite a long time. In a view of the awareness and concern for the problems created by the polymeric solid wastes, new biodegradable cellulosic composite with low cost and nontoxic materials, have been designed and developed. However, the properties of natural fibers that tends to absorb water, thus limiting their application. In this study,precipitated calcium carbonate (PCC) was added with stearic acid (SA) in order to generate a hydrophobic coating formulation. PCC works as filler and SA acts as surface hydrophobic modification agent. Polymer latex was then added to the coating compound as the binder. The composite surface morphology was inspected using scanning electron microscope (SEM). Results show that durian peel composite sheet had successfully achieved a superhydrophobic surface with a water contact angle of 154.85° which exceed 150°

Design Of Compact Pre-Pregger Machine For In House Production Of Pre-Preg Material

The main idea of this project is to conceptually design and simulate a lab-scale pre-pregger machine for in house production of pre-preg material. The aim is to decrease the size of the existing machine and reduce the cost to fabricate it. The concept design of the machine focuses on four major components: drum, resin bath, guider and fiber spindle. The pre-pregger machine is designed with an adaptable drum parameter which can be installed and removed easily from the drum holder. In this project, Programmable Logic Controller (PLC) was used to control the pre-pregger machine. The CXONE OMRON PLC was chosen to design the ladder diagram of the controller. In order to simulate and test the correctness of the controller, a simple electrical setup has been made. The setup consists of three motors, few sensors and push button. The simulated setup proved that the proposed conceptual design of the pre-pregger machine is workable

Influence Of Pulping Process Conditions Towards Better Water Resistant Effect Of Durian Shell Paper By Lignin: Two Level Factorial Design Approach

Chemical pulping of durian shell fiber is a comparatively new approach in the field of pulping, and the paper industry as a whole. Pressures of rising wood resource consumption have resulted in increased attention on the use of non-wood raw materials in the papermaking industry. This situation is due to trees being exploited in high numbers for the purpose of paper manufacturing. Thus, some alternative solutions have been developed to remedy this. Natural resources wastes like kenaf, bamboo and sugarcane bagasse are used as the raw material to produce these varied grades of paper. Additionally, cellulose fiber possesses a natural tendency to absorb moist and water vapor from the surrounding, producing weak mechanical properties and limiting paper's use. Therefore, in this study, lignin acts as a natural plasticizer in plant cell wall has been optimized to overcome the hygroscopic issue. An optimal amount of lignin will generate maximum hydrophobic effect to prepare for the production of water resistant paper. The process is optimized under the influence of three operational variables; 1) % of NaOH, 2) cooking temperature, and 3) period of cooking. To analyze the response, two level factorial design method by Design Expert v.6.0.8 software has been used. The results show that the highest water contact angle reading of 70.33° has been achieved at the condition of 17 % alkalinity, 140 °C of cooking temperature and 120 min of cooking period. At the same process condition, the highest amount of lignin (57.67 %) has also been obtained which showing the significant interaction between lignin and the hydrophobic effect. From the analysis of variance (ANOVA), all parameters have significantly affected the reading of water contact angle. The P-value of the experiment model is less than 0.0001 and the coefficient of determination value (R2) is 1.000. This conclusively suggested that the model is significant and influences on the precision and process-ability of the production

Integriti pengguna media sosial / Intan Syahriza Azizan...[et al.]

Malaysia amnya, mempunyai kepelbagaian saluran media massa. Kepelbagaian media massa boleh diklasifikasikan kepada beberapa item iaitu saluran tradisional dan saluran konvensional termasuklah media sosial seperti internet. Saluran media sosial merupakan satu platform interaksi, penyampaian maklumat dan propaganda, wadah pembelajaran serta sumber rujukan interaktif dan kreatif. Perkembangan saluran media massa ini bertambah pesat di mana penyebaran maklumat berlaku setiap saat tanpa batasan. Justeru itu, untuk memelihara integriti pengguna proses pemantauan harus sentiasa diimplementasikan dan dilestarikan demi kesejahteraan semua dan nama baik negara. Pola perbincangan penulisan ini lebih bersandarkan kepada pola kepentingan nilai dan integeriti pengguna media sosial, kerangka teori yang berkait dengan media sosial, isu-isu yang dihubungkaitkan dengan saluran media sosial, dan diakhiri dengan beberapa cadangan pengukuhan integriti. Diharapkan penulisan kertas kerja ini dapat memberikan sedikit impak positif agar setiap pengamal saluran media sosial dapat mengadaptasikan nilai-nilai integriti dalam penyediaan bahan maklumat untuk saluran masing-masing

Synthesis Of a Fe2o3 Nanowires/MWCNTS Composite For Photocatalyst

Multi-walled carbon nanotube (MWCNTs) was decorated on nanowires iron oxide (α-Fe2O3) thin film (α-Fe2O3/MWCNTs) by spin coating method.Nanowires hematite was produced by thermal oxidation of Fe substrate at 400 °C for 120 minutes.The aim of this nanocomposite α-Fe2O3/MWCNT is to improve the photocatalytic efficiency of the α-Fe2O3 nanowires.The structural characterization of the as-prepared composites were analyzed by x-ray diffraction (XRD),raman spectra,and photoluminescence spectra (PL) to identify the structure of pure α-Fe2O3 and decorated of MWCNTs.While,the morphological observation,interaction of MWCNTs and nanowires structure on hematite phase was done by scanning electron microscopy (FESEM).It was found that,the optimization dispersion of MWCNTs in the dimethyl form amide (DMF) solvent through acid treatment with 3 Molar nitric acid (HNO₃),shows the homogenized well-decorated MWCNTs on the surface of the nanowires structure,which can eliminate the limitation of iron oxide and help in electron transfer from α-Fe2O3 to MWCNTs