Design Of Microhotplate Based Gas Sensing System [TK7875. Z21 2008 f rb].

The purpose of this research is to design, fabricate and characterize a microhotplate based gas sensing system. Tujuan kajian ini adalah untuk merekabentuk, fabrikat dan mencirikan system pengesan gas berasaskan microhotplate

Investigating students’ perception towards economics education / Azniza Ahmad Zaini, Roslilee Abdul Halim and Zulkifli Ab. Ghani Hilmi

This paper investigates the perception and attitudes of non-business major students in Universiti Teknologi MARA (UiTM) towards economics education and their relationship on students’ academic performance. One of the key performance indicators in the academic programme of the university is to achieve less than twenty percent failures in all subjects offered. A four-semester examination results revealed that students constantly obtained high failure rate in two economics introductory subjects. Using students taking these two economics courses as respondents, dimensions of attitudes towards economics education were identified through the use of an exploratory factor analysis. Four factors were extracted from a 26-item questionnaire identified as ‘Value’, ‘Difficulty’, ‘Cognitive’ and ‘Affective’. Cronbach’s Alpha for the four factors was acceptable. The findings suggested that there was no significant difference between male and female students on the four dimensions of attitude even though the achievement of female students’ was higher than males. Students who did not perform were found to have a more negative attitude on the four dimensions of attitude compared to those who performed. Regression of the final exam scores on the four latent variables obtained from the factor analysis revealed that subject difficulty and gender, taken together, were significantly associated with students’ achievement

Cultivation and characteristics of aerobic granular sludge for simultaneous organics and nutrients removal performances at high temperature

With inoculum sludge from a conventional activated sludge wastewater treatment plant, a sequencing batch reactor fed with synthetic wastewater was operated at 50 ± 1 °C to study the formation of aerobic granular sludge (AGS) for simultaneous organics and nutrients removal with a complete cycle time of 3 h. The AGS were successfully cultivated with excellent settling ability and demonstrated exceptional performance in the organics and nutrients removal with influent loading rate and COD/N ratio of 1.6 kg COD (L.d)-1 and 8.3, respectively. Stable, regular, dense and fast settling granule (average diameter, 2.0 mm and settling velocity, 26 m h-1) were developed in a single reactor. In addition, 76% COD removal efficiency was observed in the system at the maturation stage of the granulation, while its ammonia and total phosphorus removal efficiencies were up to 88% and 69%, respectively. The study demonstrated the capabilities of AGS formation in a single, high and slender column type-bioreactor at high temperature which is suitable to be applied for hot climate and low humidity condition (e.g. Saudi Arabia)

Characteristics and performance of aerobic granular sludge for domestic wastewater treatment at 30°C

This study investigates the formation of AGS for domestic wastewater treatment applications in hot climate and low humidity conditions (e.g. Arab Saudi) as well as to characterize its performance in removal of nutrients and organic matter. AGS (seeded with domestic sludge from Al-Madina Wastewater Treatment Plant and fed with synthetic wastewater) with an organic loading rate (OLR) of 1.6 kg COD m3d was successfully cultivated with average size of 1-2 mm in lab scaled SBR operated at 30 days with complete cycle time of 3 h at 30 ± 1°C. Results shown the AGS formed had excellent settling ability (average diameter settling velocity, and MLSS) and exceptional performance in COD and nutrient removal with removal efficiency more than 90%

Development and characteristics of aerobic granular sludge at 40°C

This study is conducted to develop aerobic granular sludge (AGS) for domestic wastewater treatment application in a hot climate and low humidity condition such as for Middle East countries e.g. Saudi Arabia and to investigate the performance of the granular sludge in organic matter and nutrient removal by using sequencing batch reactor (SBR). The operation of the reactor was based on the SBR system with a complete cycle time of 3 hours (5 min of feeding, 140 min of aeration, 15 to 30 min of settling, 5 min of discharging and 3 min idling) and operated at 1.6 g COD / L.d organic loading rate. Granular sludge was developed at temperature 40ºC in 30 days operation by using synthetic wastewater as the influent. Result showed that developed granular sludge had good settling ability with average size of the granules was found to be 1.03 to 2.42 mm. Meanwhile, the removal efficiencies of chemical oxygen demand (COD), ammonia nitrogen (NH3-N) and total phosphorus (TP) are 87.31%, 91.93% and 61.25%. The study shows AGS can be developed at high temperature and capable to treat organics and nutrients present in domestic wastewater at hot climates and low humidity condition

Aerobic sludge granulation at high temperature-low humidity for domestic wastewater treatment

With inoculum sludge from a conventional activated sludge wastewater treatment plant, a sequencing batch reactor fed with domestic wastewater was operated at 50 ± 1 "C and pH 7 ±, to study the formation of aerobic granular sludge (AGS)for simultaneous organics and nutrients removal with a complete cycle time of 3 h. The AGS were successfully cultivated with excellent settling ability and demonstrated exceptional performance in the organics and nutrients removal with influent loading rate and CO/N ratio of 1.6 kg COD (L..d ):' and 8.3, respectively. Stable, regular, dense and fast settling granule (average diameter, 1.5 mm; settling velocity, 33 m h': and sludge volume index, 22.3 mL g-l) were developed in a single reactor. In addition, 96.5% COD removal efficiency was ob served in the system at the maturation stage of the granulation, while its ammonia and total nitrogen removal efficiencies were up to 94.7% and 89.4%, respectively. The study demonstrated the capabilities of AGS formation in a single, high and slender column type-bioreactor at high temperature which suitable to be applied for hot climate and low humidity countries (e.g. Saudi Arabia)

Development of aerobic granules in sequencing batch reactor system for treating high temperature domestic wastewater

The application of aerobic granular sludge (AGS) in treating real domestic wastewater at high temperature is still lacking. In this study, the microstructure and morphology of the granules, as well as bioreactor performance, were investigated during the treatment of real domestic wastewater at high temperature (50 °C). The experiment was executed in a sequencing batch reactor (SBR) with a complete cycle time of 3 hours for the treatment of low-strength domestic wastewater at an organic loading rate (OLR) of 0.6 kg COD m−3 d−1. Stable mature granules with average diameters between 2.0 and 5.0 mm, and good biomass concentration of 5.8 g L−1 were observed in the bioreactor. AGS achieved promising results in the treatment of domestic wastewater with good removal rates of 84.4 %, 99.6 % and 81.7 % for chemical oxygen demand (COD), ammoniacal nitrogen (NH3−N), and total phosphorus (TP), respectively. The study demonstrated the formation capabilities of AGS in a single, high and slender column type-bioreactor at high temperature which is suitable to be applied in hot climate condition areas especially countries with tropical and desert-like climates

Stability of Chlorine Termination on Ge(100) and Ge(111) Surfaces

The different cleaning solution; HCl and HF solution are used to remove the suboxide and oxide component on Ge surface. The HCl cleaning results chlorine (Cl) termination on Ge surface whereas no Fluorine (F) termination was observed just after HF cleaning. The growth of Ge oxide is studied after treated with HCl cleaning on two surface orientations; (100) and (111), respectively in dry oxygen ambient and cleanroom air by spectroscopic ellipsometry (SE) and x-ray photoelectron spectroscopy (XPS). A clear step and terrace trend was observed for the oxidation growth of Ge (100) and Ge (111) in dry oxygen ambient compared to in clean room air. This trend shows the difference in surface reaction of Ge oxidation as humidity varies. The stability of chlorine termination of Ge (111) than Ge (100) explains the slower growth of oxidation in dry oxygen ambient