Characteristics Of Titanium Dioxide Nanotubes Annealed Under Various Conditions And Quenched Using Liquid Nitrogen

This paper presents the effects of the different annealing treatments and quenching conditions on the characteristics of titanium dioxide nanotubes (TNTs), which were synthesised successfully via two-step anodization. The X-ray diffraction (XRD) showed that TNTs annealed and quenched using liquid nitrogen (N2) exhibited significant dissimilarities in the phase transition and plane dominance, as compared to that of air quenched. It also revealed that the liquid N2 quenching was capable of suppressing the phase transition of anatase into rutile. Apart from that, the elemental analysis showed that liquid N2 quenching led to Leidenfrost effect, which had affected the Ti:O ratio of the TNTs significantly. Morphologically, the use of controllable water vapour/N2 was found to be able to preserve the nanotubular structures, even at the high annealing temperature of 850 °C. From the optical aspect, the bandgap energy of all samples were found to decrease when the annealing temperatures increased, regardless of the annealing and quenching conditions. Particularly, the crystal structure of TNTs was found to exert greater effect on their bandgap energy, as compared to that of crystallite size when the annealing temperatures were varied between 650 °C and 850 °C

DEVELOPMENT OF REGIONAL TSS ALGORITHM OVER PENANG USING MODIS TERRA (250 M) SURFACE REFLECTANCE PRODUCT

Total suspended sediment (TSS) plays a significant role in the environment. Many researchers show that TSS has a high correlation with the red portion of the visible light spectrum. The correlation is highly dependent on geography of the study area. The aim of this study was to develop specific algorithms utilizing corrected MODIS Terra 250-m surface reflectance (Rrs) product (MOD09) to map TSS over the Penang coastal area. Field measurements of TSS were performed during two cruise trips that were conducted on 8 December 2008 and 29 January 2010 over the Penang coastal area. The relationship between TSS and the surface reflectance of MOD09 was analysed using regression analysis. The developed algorithm showed that Rrs are highly correlated with the in-situ TSS with R2 is 0.838. The result shows that the Rrs product could be used to estimate TSS over the Penang area

A review of clinical and surgical outcomes of endoscopic endonasal skull base surgery in a Tertiary Center in Sarawak

Background: Endoscopic endonasal approach (EEA) for skull base tumor has been extensively developed in recent years. Objectives: To review the demographic data, indications, clinical presentations and surgical outcomes of endoscopic endonasal skull base surgeries performed. Methods: A retrospective analysis on all patients who had undergone endoscopic endonasal skull base surgery at the Skull Base Unit (ENT & Neurosurgery) from December 2013 to December 2015. Results: A total 34 cases were operated on during the study period. Female patients account for 44% of patients while 56% were male patients, with ages ranging from 8 to 77 years, with the mean age of 51.88 years. Majority of the cases were pituitary tumors (41%), followed by sinonasal tumors (15%), meningioma (12%), clival tumor (8%), cerebrospinal fluid (CSF) leak repair (8%) and frontal mucocoele (6%). Transsellar approach was the commonest approach (41%) followed by the transclival, transplanum, transfrontal approaches. In about 80% of cases, CSF leak was encountered intraoperatively and was successfully repaired endoscopically with the Hadad-Bassagasteguy flap and with the insertion of a lumbar drain. Only one case (3%) of CSF leak was noted postoperatively which was then successful repaired endoscopically with a nasoseptal flap. Systemic complications and intracranial infections were seen in 3 cases (8%) and were managed accordingly. No cases of epitaxis requiring surgical intervention were noted post operatively

Groundwater potentiality mapping using geoelectrical-based aquifer hydraulic parameters: A GIS-based multi-criteria decision analysis modeling approach

This study conducted a robust analysis on acquired 2D resistivity imaging data and borehole pumping test records to optimize groundwater potentiality mapping in Perak province, Malaysia using derived aquifer hydraulic properties. The transverse resistance (TR) parameter was determined from the interpreted 2D resistivity imaging data by applying the Dar-Zarrouk parameter equation. Linear regression and GIS techniques were used to regress the estimated values for TR parameters with the aquifer transmissivity values extracted from the geospatially produced BPT records-based aquifer transmissivity map to develop the aquifer transmissivity parameter predictive (ATPP) model. The reliability evaluated ATPP model using the Theil inequality coefficient measurement approach was used to establish geoelectrical-based hydraulic parameters (GHP) modeling equations for the modeling of transmissivity (Tr), hydraulic conductivity (K), storativity (St), and hydraulic diffusivity (D) properties. The applied GHP modeling equation results to the delineated aquifer media was used to produce aquifer potential conditioning factor maps for Tr, K, St, and D. The maps were modeled to develop an aquifer potential mapping index (APMI) model via applying the multi-criteria decision analysis-analytic hierarchy process principle. The area groundwater reservoir productivity potential model map produced based on the processed APMI model estimates in the GIS environment was found to be 71% accurate. This study establishes a good alternative approach to determine aquifer hydraulic parameters even in areas where pumping test information is unavailable using a cost effective geophysical data. The produced map can be explored for hydrological decision making

Variability and Trend in Integrated Water Vapour from ERA-Interim and IGRA2 Observations over Peninsular Malaysia

Integrated water vapour (IWV) is the total amount of precipitable water in an atmospheric column between the Earth’s surface and space. The implication of its variability and trend on the Earth’s radiation budget and precipitation makes its monitoring on a regular basis important. ERA-Interim reanalysis (ERA) and radiosonde (RS) data from 1988 to 2018 were used to investigate variability and trend in IWV over Peninsular Malaysia. ERA performed excellently when gauged with RS. Trend analysis was performed using the non-parametric Mann–Kendall and Theil–Sen slope estimator tests. ERA and RS IWV revealed double fluctuations at the seasonal time scale, with maxima in May and November, which are the respective beginnings of the southwest monsoon (SWM) and northeast monsoon (NEM) seasons, as well as coincidental peaks of precipitation in the region. IWV decreased in a southeast–northwest orientation, with regional maximum domiciled over the southeastern tip of the region. Steep orography tended to shape intense horizontal gradients along the edges of the peninsular, with richer gradients manifesting along the western boundary during SWM, which harbours more water vapour in the peninsular. IWV trends, both at the annual and seasonal time series, were positive and statistically significant at the 95% level across the stations, except at Kota Bharu, where a nonsignificant downward trend manifested. Trends were mostly higher in the NEM, with the greatest rate being 0.20 ± 0.42 kgm−2 found at Penang. Overall, the IWV trend in Peninsular Malaysia was positive and consistent with the upward global changes in IWV reported elsewhere