Nilai C1/Br dan Halida/pb di dalam minyak petrol tempatan

Unsur Br (dan C1) juga) sering dikaitkan dengan logam Pb sebagai bahan pencemaran dari ekzos automobile, sehubungan dengan ini, kajian telah dijalankan bagi menganalisis unsure Br dan C1 di dalam sample minyak petrol daripada 6 buah syarikat pengeluar minyak petrol terkemuka di Negara ini. Nisbah C1/Br yang diperolehi adalah di antara 0.017 - 0.515, manakala nisbah puratanya ialah 0.322  0.200. Anggaran purata Br/Pb ialah 0.862, manakala nilai purata bagi C1/Pb ialah 0.195. Keputusan kajian tersebut menunjukkan bahawa nilai Br/Pb dan C1/Pb di dalam petrol tempatan tidak sama dengan yang terdapat di Negara-negara lain. Seterusnya faktor-faktor yang menyebabkan perbezaan ini dibincangkan di dalam kertas kerja ini

Characterization of Fine and Coarse Atmospheric Aerosols in Kuala Lumpur

From July 1988 to December 1990 daily samples of atmospheric aerosols segregated into fine particlas, FP (aerodynamic diameter, da 2.5 !Lm) and coarse particles, CP (2.5!Lm ~ da ~ 10 !Lm) were collected using a dichotomous sampler sited at the Universiti Teknologi Malaysia, Kuala Lumpur. Eighteen elements (AJ, As, Br, Ca, Cl, Co, Fe, K, Mn, Na, i, P, Pb, S, Sb, Si, V, and Zn) were determined from the aerosol samples. On average, the total elemental concentration made up 19, 33, and 23% of the FP, CP, and TP (TP=FP+CP) fractions respectively, and approximately 70% of As, Br, K, Na, Pb, S, and V were found to be in the fine fraction. Both Sand Si constituted the largest percentage of the total elemental concentration of 61 and 44% in the FP and CP fractions, respectively. Based on a source apportionment study, the soil and marine environments contributed 21 and 5% of the TP fraction while the remaining 74% of the aerosol concentration is yet to be explained

Portable heart valve disease screening device using electronic stethoscope

Heart sound analysis has been a popular topic of studies since a few decades ago. Most of the studies are done in PC platform since embedding the complex algorithm into a simple small device such as microcontroller board seems to be very difficult due to limited processing speed and memory. This study classifies normal and abnormal heart sound signal from four categories of Heart Valve Disease. An automated system that consists of segmentation, feature extraction and classification of the heart sound signal is developed in PC and hardware platforms. A multimedia board completed with a single board computer, audio codec and graphic LCD is used to make a portable heart valve disease screening device with electronic stethoscope as the input for the system. Both system recorded 96.3% specificity. However, the portable device has only 77.78% sensitivity and 87.04% accuracy compared to PC platform that have sensitivity and accuracy of more than 90%

Continuous Production of Carbon Nanotubes - A Review.

Carbon nanotubes (CNTs) up to now are the most researched materials of the 21st century with an international intention of growing industrial quantities due to their superior properties for use in many applications. Thus far large quantities of carbon nanotube scan be grown in a continuous manner by both arc as well as chemical vapour deposition methods. In this paper, an innovative approach of feeding gases, a carbon precursor (solid or gases) and a catalyst into the reaction zone is reviewed. This is followed by a study of the reaction process concerning how the method is initiated, the effect of growth environment and catalyst on CNTs as well as the discharging mechanism for the final carbon products. A study of the arc method consists of a novel way of growing CNTs in a liquid solution from an arc discharge generated by carbon rods, by growing CNTs in a plasma zone using carbon gases or solid carbon and a more direct method of using carbon tape as the anode for the synthesized source are also reported. In the case of the chemical vapour deposition (CVD) method, some use a horizontal reactor and some use a vertical reactor with all having different installed devices for use in continuous feeding and discharging of resources and products respectively. Additionally, problems regarding the CNT yield and some issues that have not been taken into consideration by others, are discussed. At the end of the review, an additional mechanism to integrate catalyst preparation and carbon nanotube purification into the current research synthesizing process for future study is proposed for a highly productive continuous CNT synthesis process

Using chemometrics in assessing langat river water quality and designing a cost-effective water sampling strategy.

Seasonally dependent water quality data of Langat River was investigated during the period of December 2001 – May 2002, when twenty-four monthly samples were collected from four different plots containing up to 17 stations. For each sample, sixteen physico-chemical parameters were measured in situ. Multivariate treatments using cluster analysis, principal component analysis and factorial design were employed, in which the data were characterised as a function of season and sampling site, thus enabling significant discriminating factors to be discovered. Cluster analysis study based on data which were characterised as a function of sampling sites showed that at a chord distance of 75.25 two clusters are formed. Cluster I consists of 6 samples while Cluster II consists of 18 samples. The sampling plots from which these samples were taken are readily identified and the two clusters are discussed in terms of data variability. In addition, varimax rotations of principal components, which result in varimax factors, were used in interpreting the sources of pollution within the area. The work demonstrates the importance of historical data, if they are available, in planning sampling strategies to achieve desired research objectives, as well as to highlight the possibility of determining the optimum number of sampling stations which in turn would reduce cost and time of sampling

Physical and Mechanical Properties of Flame Retardant-Treated Hibiscus Cannabinus Particleboard

Physical and mechanical properties of flame retardant-treated kenaf particleboards were studied using physical tests such as water absorption, thickness swelling and mechanical tests such as modulus of rupture (MOR), modulus of elasticity (MOE) and internal bond (IB). The kenaf core particles were treated with 10% concentrations of three types of flame retardants namely diammonium phosphate (NH4)2HPO4), monoammnium phosphate (NH4)HPO4) and BP® [mixture of 27-33 % boric acid, 67-73 % guanylurea phosphate and 0.0-4.2 % phosphoric acid]. The study showed that DAP-treated particleboards complied with the thickness swelling and water absorption of British-European standard [BS EN 317:1993] requirements. BP®-treated particleboards were found to have performance values superior than the British-European standard requirement values for MOR [BS EN 310:1993] and MOE [BS EN 310:1996]. MAP-treated particleboards surpassed the standard requirement value for IB [BS EN 319:1993]. However, all treated particleboards complied with the standard requirement value of MOE except DAP-treated particleboards. The untreated particleboards complied with all the standard requirements of the physical and mechanical tests. Overall, the flame retardants affected the physical and mechanical properties of the kenaf core particleboar

Kesan ketebalan filem terhadap fotoelektrokimia titania dioksida (TiO2) yang disediakan melalui kaedah pemendapan bantuan aerosol wap kimia (AACVD)

Titanium oksida (TiO2) merupakan semikonduktor yang mempunyai jurang jalur yang besar dengan ciri-ciri foto penukaran dalam spektra UV sesuai digunakan dalam pelbagai aplikasi. Dalam penyelidikan ini, kaedah pemendapan bantuan aerosol wap kimia (AACVD) digunakan bagi menghasilkan lapisan filem TiO2 dengan ketebalan yang berbeza berdasarkan tempoh pemendapan yang dikenakan (3, 5 dan 7 min). Lapisan filem dimendapkan pada suhu 450oC. Melalui kedah AACVD, lapisan TiO2 yang dimendapkan di atas kaca FTO (florin dop tin oksida) akan menjadi lebih nipis dan struktur lapisan menjadi lebih padat.Titanium diisopropoxide bis(acetylacetonate) dan etanol digunakan untuk menghasilkan pelopor AACVD. Ciri morfologi dan ketebalan filem nipis TiO2 diuji menggunakan mikroskopi daya atom (AFM) yang menunjukkan permukaan berliang pada filem nipis tersebut. Ciri optik filem nipis TiO2 diuji menggunakan spektra pancaran ultra-lembayung cahaya nampak (UV-Vis) dan keputusan menunjukkan filem nipis memberikan ketelusan yang tinggi pada kawasan kelihatan berdasarkan jurang jalur yang diperolehi. Prestasi filem nipis dicirikan menggunakan voltammetri sapuan linear (LSV) dan spektroskopi impedans elektrokimia (EIS). TiO2-5 min memperoleh purata ketebalan 61 nm melihatkan prestasi J-V terbaik iaitu 6.30 x 10-4 A/cm-2 dan memberikan rintangan cas yang terendah. Tambahan, pemendapan filem menunjukkan kelekatan yang baik pada substrat, kebolehkeluaran semula dan permukaan filem nipis yang sekata. Berdasarkan keputusan yang diperolehi, TiO2 yang disediakan menggunakan kaedah AACVD sangat sesuai digunakan dalam pelbagai aplikasi seperti sel suria generasi ketiga yang memerlukan filem nipis dengan ketebalan yang rendah, berliang, ketelusan yang tinggi, fotoaktif, dan stabil