Fabrication of highly ordered TiO2 Nanotubes from Fluoride containing Aqueous Electrolyte by Anodic Oxidation and their Photoelectrochemical response.

The fabrication of TiO2 nanotubes (TNT) was carried out by electrochemical anodization of Ti in aqueous electrolyte containing NH4F. The effect of electrolyte pH, applied voltage, fluoride concentration and anodization duration on the formation of TNT was investigated. It was observed that self-organized TNT can be formed by adjusting the electrolyte to pH 2-4 whereby applied voltage of 10-20 V can be performed to produce highly ordered, well-organized TNT. At 20 V, TNT can be fabricated in the concentration range of 0.07 M to 0.20 M NH4F. Higher fluoride concentration leads to etching of Ti surface and reveals the Ti grain boundaries. The prepared TNT films also show an increase in depth and in size with time and the growth of TNT films reach a steady state after 120 minutes. The morphology and geometrical aspect of the TNT would be an important factor influencing the photoelectrochemical response, with higher photocurrent response is generally associated with thicker layer of TNT. Consequently, one can tailor the resulting TNT to desired surface morphologies by simply manipulating the electrochemical parameters for wide applications such as solar energy conversion and photoelectrocatalysis

Preparation and characterization of nanostructured TiO2 via electrochemical anodization in aqueous ammonium fluoride

Electrochemical anodization of titanium (Ti) in acidic fluorinated electrolyte has emerged as a simple and straightforward method to synthesize TiO2 coating on Ti substrates directly. In this study, attempt was made to perform the anodic oxidation of Ti foil in a standard two-electrode bath containing relatively mild electrolyte, NH4F at various potentials for 1 hour. The resulting TiO2 films were characterized with X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) and linear sweep photovoltammetry. XRD analysis revealed the amorphous nature of the as-anodized samples which crystallize after calcination in open air atmosphere at 500 oC for 2 hours. TiO2 films synthesized via anodization on polished Ti substrate demonstrated pure anatase phase only whereas anodization of etched Ti foil with HNO3 showed a mixture of anatase and rutile phase. Different morphologies of TiO2 could be obtained depending on the applied voltage used. Both as-anodized and calcined TiO2 films showed photocurrent response when illuminated from 300 W halogen lamp with that synthesized via anodization of etched Ti foil exhibited relatively higher photocurrent than the other samples, demonstrating the important of surface treatment of Ti on the photoelectrochemical response of TiO2 film

The effect of heat treatment on phase transformation, morphology and photoelectrochemical response of short TiO2 nanotubes.

TiO2 nanotubes (TNT) have attracted considerable attention due to large specific surface area in a small geoetrical area and fewer interfacial grain boundaries. However, thermal stability and crystalline phase of TNT greatly affects their potential applications in the areas of photocatalysis, optoelectronics and gas sensing. Thus, thermal stability and phase transition of highly ordered TNT via calcination from 200-800 oC were studied in open air atmosphere. The results indicated that the as-anodized TNT is amorphous and transformed to anatase phase at 300 oC. Crystallization of anatase phase increases on elevating calcination temperature and rutile phase co-existed at 500 oC. No discernable changes in the nanotubes dimensions were found and TNT is thermally stable up to temperature lower than 600 oC, above which significant sintering of TNT occurred. At 800 oC, grain growth and oxidation of Ti resulted in completely collapsed of TNT to dense rutile crystallites. Photoelectrochemical response of calcined TNT enhanced substantially with respect to that of as-anodized samples and gradually increased with elevating temperature up to 500 oC after which they decreased, which was probably ascribed to changes in phase structural and morphological properties of TNT

High Prevalence of Alpha- and Beta-Thalassemia in the Kadazandusuns in East Malaysia: Challenges in Providing Effective Health Care for an Indigenous Group

Thalassemia can lead to severe transfusion-dependent anemia, and it is the most common genetic disorder in Malaysia. This paper aims to determine the prevalence of thalassemia in the Kadazandusuns, the largest indigenous group in Sabah, East Malaysia. α- and β-thalassemia were confirmed in 33.6% and 12.8%, of the individuals studied respectively. The high prevalence of α- and β-thalassemia in the Kadazandusuns indicates that thalassemia screening, genetic counseling, and prenatal diagnosis should be included as part of their healthcare system. This preliminary paper serves as a baseline for further investigations into the health and genetic defects of the major indigenous population in Sabah, East Malaysia

Morphology and dimensions controlled of Titania nanotubes in mixed oganic-inorganic electrolyte

The formation of self-organized and highly ordered Titania nanotubes was achieved by anodisation of Ti in a mixture of water-ethylene glycol electrolyte. Control over the dimensions and morphology of nanotubes was successfully established by changing the anodisation voltage, the ammonium fluoride (NH4F) concentration and the anodisation time. A threshold voltage of 5 V is required for nanotube formation. Collapsed tubes were formed by applying electrochemical etching at high fluoride concentration. This study also showed that the nanotube lengths ranging from 0.5 to 2.6 μm could be formed by controlling the voltage applied and fluoride concentration with preferred growth along the c-axis

Photocatalytic study of two-dimensional ZnO nanopellets in the decomposition of methylene blue

We report several significant photodecomposition rates of methylene blue (MB) obtained before and after the refluxing process of own-synthesized two-dimensional (2D) zinc oxide (ZnO) nanopellets. Each photodecomposition rate of MB was found highly dependent on the weight of photocatalyst. The existing photodecomposition rate has been successfully improved to a factor of 22.0 times through refluxing process in excessive pyridine where the surface capping ligand (oleic acid) is removed from the 2D ZnO nanopellets. On the other hand, the refluxed photocatalyst (0.04 g) in this study was found to exhibit excellent recyclability up to three cycles. Furthermore, X-ray powder diffraction spectrums for the refluxed photocatatalyst, respectively, before and after three cycles of photocatalytic reactions, has generated the same patterns showing that the photocatalyst is stable and feasible to be used as an efficient photocatalyst material. Hence, these 2D ZnO nanopellets would provide a new alternative route as a highly efficient photocatalyst for wastewater treatment

Application of Building Information Modelling (BIM) Technology in Drainage System Using Autodesk InfraWorks 360 Software

The increased number of physical drainage drawings at Samarahan district, Sarawak for new development areas is difficult to manage and handle by relevant authorities. Hence, this research is conducted to determine the feasibility of Building Information Technology (BIM) to create a proper drainage inventory system to accurately list and record current drainage information using Autodesk Infraworks 360 software. This inventory system will be employed to examine and validate corresponding drainage parameters based on the recorded information. Taman UniCentral, a residential neighbourhood in Kota Samarahan, has been chosen for this case study. Drainage data, such as drainage size, length, invert level, are entered into GIS-integrated Model Builder in Autodesk InfraWorks 360. Autodesk InfraWorks 360 will conduct a preliminary analysis, including watershed analysis, to delineate the catchment area and drainage performance inspections at rainfall intensities of 2, 5, 10, 20, and 50 years (ARI). Thereafter, the InfraWorks model will be exported into Autodesk Civil3D to conduct a more extensive hydraulic analysis. The results show that full integration of these two Autodesk software packages had created a proper inventory system of existing drainage information and simulated its sufficiency in catering surcharge runoff from the new development area at the upper catchment

An application of cadastral fabric system in improving positional accuracy of cadastral databases in Malaysia

Cadastral fabric is perceived as a feasible solution to improve the speed, efficiency and quality of the cadastral measurement data to implement Positional Accuracy Improvement (PAI) and to support Coordinated Cadastral System (CCS) and Dynamic Coordinated Cadastral System (DCCS) in Malaysia. In light of this, this study aims to propose a system to upgrade the positional accuracy of the existing cadastral system through the utilisation of the cadastral fabric system. A comprehensive investigation on the capability of the proposed system is carried out. A total of four evaluation aspects is incorporated in the study to investigate the feasibility and capability of the software, viz. performance of geodetic least squares adjustment, quality assurance techniques, supporting functions, and user friendliness. This study utilises secondary data obtained from the Department of Surveying and Mapping Malaysia (DSMM). The test area is coded as Block B21701 which is located in Selangor, Malaysia. Results show that least square adjustment for the entire network is completed in a timely manner. Various quality assurance techniques are implementable, namely error ellipses, magnitude of correction vectors and adjustment trajectory, as well as inspection of adjusted online bearings. In addition, the system supports coordinate versioning, coordinates of various datum or projection. Last but not least, user friendliness of the system is identified through the software interface, interaction and automation functions. With that, it is concluded that the proposed system is highly feasible and capable to create a Cadastral Fabric to improve the positional accuracy of existing cadastral system used in Malaysia