Archives-November 2011

Assessment on rivers and streams water quality should incorporate aspects of chemical, physical, and biological. The objective of this paper was to review the current primary concerned aspects and practiced method in river water quality research in Malaysia. The present day, method of determining river water quality in Malaysia is based mainly on physical and chemical parameters. Concentration on chemical and physical parameters is particularly surprising in judging natural waters where the main aim is often preservation of biological amenities. Numerous studies have indicated biological method has many advantages over chemical and physical method, such as; cheaper, easier, less time consuming, reliable, and can give indications of water quality for a long period of time. We do not advocate to abandoning physical and chemical assessments; rather, we note the inadequacy of the assessments to give complete information on river water quality. Therefore, Malaysia should start to anticipate and integrate the biological aspects into water quality studies and extensively make use of them to improve water quality monitoring in Malaysia. Successfulness on this will enhance water quality monitoring and management in Malaysia.

Thin layer chromatographic technique with silica gel – ethyl acetate adsorbent - solvent system has been validated for the determination of herbicides. Precision of the method determined in terms of reproducibility yielded relative standard deviation of 0.3 % and 0.5 % for the Rf of the herbicides and diameter of spots respectively. The minimum detectable quantity (MDQ) of the herbicides ranges from 0.20 – 0.50 ng. The method has been applied to determine the efficiencies of acetone, acetonitrile, methanol, hexane and acetone/hexane (4:1) for the recovery of the herbicides, atrazine, ametryne, propanil, diuron and nitrofen in a forest zone soil in Ghana. Acetone and acetonitrile were found to have approximately equal efficiency as extraction solvents. Extraction with acetone, acetonitrile, acetone/hexane (4:1) yielded more than 90% recovery for all the herbicides. The highest recovery efficiency of 96.2% was obtained for atrazine using acetone. Extraction with methanol and hexane gave relatively low recoveries particularly, with the clean up extracts. In all, the clean up procedure with SPE cartridge equipped with C-18 as adsorbent reduced recovery by 9 – 13 %.

Localized heating is poised to become an integral part of microfluidic devices in various life-science applications. The elimination of cancer cells are done using resistive heating method. Many methods are adopted for cancer elimination. But this method will be more useful for elimination the cancer cells. By using mems, COMSOL Multiphysics technique by resistive heating method the cancer cells will be get eliminated. This is catalyzed by the scale of economics, the advantageous fluidic behavior at small volumes, and the ever increasing need for rapid and high throughput assays for pharmaceutical industry and other combinatorial based studies. For precision confined heating, thin film resistive heaters have proven to be superior to the conventionally used Peltier elements, which are often a hindrance to miniaturization and functionality integration for thermally sensitive application. The resistivity of certain metals varies predictably with temperature, making them suitable for use as temperature sensors. If a thin film could be designed so that it preserves a uniform temperature distribution during heating, its total resistance would accurately reflect its temperature, allowing it to simultaneously act as both a temperature sensor and a heater.

Improving distribution systems performance has become a significant issue as a result of large increase in electrical power consumption during recent years. The system operators aim to enhance efficiency of the distribution system in both dynamic and static modes. While DFACTS has commonly been employed to promote distribution systems capability in dynamic mode, this paper proposes a new static technique based on using interline dynamic voltage restorer (IDVR) to make a virtual smooth load duration curve for the adjacent loads having different load curves. Such a technique can be used for peak shaving and help the operator postpones the system expansion necessity. Furthermore, as a result of virtual smoothing load duration curve, voltage security margin and system reliability which are two important topics in static performance of the distribution systems will be enhanced. The simulation results demonstrate the suitability of the proposed technique.

Sensing and controlling of humidity and temperature is a major issue in various industries. This paper presents the design, fabrication and complete characterization of a Micro Cantilever based Humidity sensor integrated with a temperature sensor. A Si Cantilever based Humidity Sensor on capacitive principle is designed and various analyses were performed on the sensor. Platinum heater used in the humidity sensor is used for the vaporization of the moisture absorbed. The heater along with two gold electrodes can act as a temperature sensor so that the temperature variations can be easily detected. The temperature sensor was designed using Platinum and is of Resistance Temperature Detector {RTD} type. The temperature sensor is provided with two gold electrodes on each side. One of the electrodes is maintained at 5V DC and the other at 0V DC, enabling a current flow through the Platinum layer. When the temperature changes, the resistivity of the Platinum changes accordingly. This causes a change in the current flow through the temperature sensor. The sensor is designed in a structure that can tolerate the harsh environmental variations like pressure, temperature.

In this study, specific mathematical models for estimation of laboratory thermal conductivities from wire line log thermal conductivity within the ambience of locally oriented wells located in the Niger Delta have been established. The laboratory thermal conductivity is charactersed with high fidelity compared to wire line log thermal conductivity whose values vary with the variations and fluctuations of the lithology of the subsurface geo materials, well effects as well as the effects of the limited bed thickness of the adjacent lithological units of the Niger Delta where the study was stationed. The generalised equation kleff = 0.709 kweff + 0.188 is the model designed based on the site variables and constants of the locally oriented wells in the Niger Delta for stabilizing the unstable wire line log thermal conductivity value within the 1-2.5km depths where the oil-rich geo materials in the Niger Delta are usually found. Equations 3-9 which show inter-convertibility between laboratory and wire line log thermal conductivity have been established. These equations will be relevant in converting the usually available wire line log thermal conductivity to the usually desired and stable laboratory thermal conductivity for nearby virgin wells in the area.

The concentrations of the toxic elements As, Cd, Hg, Sb and V in well and borehole water, samples from the Bibiani mining area in the Western Region of Ghana have been measured using instrumental neutron activation analysis (INAA) following irradiation with thermal neutrons and counting with a conventional counting system. This study was conducted to assess the impact of mining activities on the ground water resources of the Bibiani mining area. The concentrations of the elements measured in the rainy season water samples were in the ranges: As, 0.04 – 6.08 mg/L; Hg, 1.63 – 2.05 mg/L; Sb, 0,52 – 0.96 mg/L and V, 0.06 – 0.62 mg/L. The concentrations of Cd were below 0.01 mg/L (i.e. the detection limit) in all the rainy season samples. In the dry season samples, the concentration ranges of the various elements were: As, 0.67 – 4.71 mg/L; Cd, 0.35 – 2.80 mg/L; Hg, 0.30 – 4.93 mg/L; Sb, 0.08 – 0.70 mg/L and V, 0.07 – 0.52 mg/L. In the rainy season, the concentrations of As in 54% of the samples, Hg in 31% of the samples, and Sb in 23% of the samples were above their respective World Health Organization (WHO) limits whereas in the dry season water samples, the concentration of As in 31% of the samples, Cd in 62% of the samples, Hg in 23% of the samples and Sb in 15% of the samples were above their respective WHO limits. The pH values of all the water samples ranging from 3.90 to 5.93 pH units fell below the lower limit of the range 6.5 – 8.5, the WHO (1985) pH range for good quality drinking water. Therefore it could be concluded on this grounds that the wells and boreholes studied in Bibiani mining area were polluted hence not suitable for human consumption.

Osteoarthritis (OA) is the most common musculoskeletal disorder worldwide. Knee and hip joints are most commonly affected by OA, and their impact on public health is remarkable. The effects of OA on an individual are also considerable. The symptoms of OA, such as pain and stiffness of the joints and muscle weakness, are serious risk factors for mobility limitation and impaired quality of life. Osteoarthritis begins in the cartilage and eventually leads to the two opposing bones eroding into each other. Laboratory tests (using X-rays) for rheumatologic problems lack the sensitivity and specificity to allow their use as screening tools. Diagnosis is the critical challenge in MEMS research. This paper deals with the design of capacitive comb drive sensor for diagnosing joint-cartilage disorder including the degradation of joints and inflammation. The comparison between various stages of osteoarthritis leads to the diagnosis

In this article, the authors propose that relationship quality model for retail banking should consist of antecedents and consequences. The antecedents proposed are relational selling behavior and positive emotional display, while the consequences are future interaction and positive word of mouth. The authors will argue that the inclusion of both antecedents and consequences will help retail banks to refine their relationship quality model.

The purpose of this study was to investigate the effects of Cognitive Load Theory on the learning among Jadara University students in Jordan. The lesson developed in two different modes, text and image (TI) and audio, image with text (AIT). A quasi experimental factorial design was adopted in this research. The independent variables were the two modes of courseware. The dependent variable was the post test score and attitude. The study sample consisted of 79 educational technologies and was randomly (simple random sample). Descriptive and inferential statistics were conducted to analyze the collected data. ANCOVA was used to determine the significant differences of the post-test scores among the groups. The findings of this study showed that students using the Text, Images (TI) mode were not significantly higher than that attained by students using the Audio, Images, Text (AIT) mode. Also the findings of this study showed that all of the differences between the attitude scores of students in two treatment groups were not significant.