1,262 research outputs found

    Optimization of chemical pretreatment for removing cobalt on tungsten carbide substrate using response surface methodology

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    Diamond coating are commonly used in industries especially for application such as cutting tools, biomedical components, optical lenses, microelectronics, engineering, and thermal management systems. The diamond coating quality is strongly depending on substrate preparation prior to diamond coating. Thus, the several process parameters must be studied to obtain optimal parameters which lead high quality diamond coating. In this present work, an attempt was made to optimize pretreatment parameters namely temperature and time on cobalt removal of tungsten carbide. Full factorial experimental designs followed by Response Surface Methodology (RSM) were employed in this study to plan and analyze the experiment. The cobalt removal was the independent response variables. Empirical model was successfully developed to predict amount of cobalt removal on the substrate after single step etching process. Experimental results have shown that the temperature, time and time2 are found to be the most significant factors for cobalt removal. Whereas for interaction of time and temperature were insignificant factors to influence cobalt removal. According to this study, the minimum cobalt content can be obtained at working temperature from 48º to 50ºC for 3 minute

    Penghasilan modul pembelajaran lukisan kejuruteraan berbantukan komputer

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    Perkembangan teknologi maklumat dalam dunia pendidikan tidak lagi boleh dinafikan pada masa kini. Keperluan yang meningkat dalam sistem pembelajaran dan pengajaran memerlukan mereka yang terlibat memberi sepenuh tumpuan terhadap mata pelajaran bagi mencapai matlamat. Untuk tujuan ini Modul Pembelajaran Lukisan Kejuruteraan berbantukan Komputer dihasilkan bagi membantu memudahkan pelajar dalam mata pelajaran Lukisan kejuruteraan. Statistik deskriptif digunakan dalam mengumpul dan menganalisis data. Secara keseluruhannya dari hasil kajian, menunjukkan para pelajar memberikan maklum balas yang positif terhadap modul ini. Semua responden memberi tindak balas positif terhadap modul dari segi mesra pengguna, isi kandungan, motivasi dan daya kognitif. Hasil dari kajian ini, didapati bahawa kebanyakan pelajar berminat terhadap Modul Pembelajaran Lukisan Kejuruteraan Berbantukan Komputer. Walau bagaimanapun masih terdapat beberapa aspek yang perlu diperbaiki untuk memantapkan modul ini

    Analysis of Agricultural Extension Methods Used by Extension Workers for Conflict Resolution among Agro – Pastoralists in Adamawa State, Nigeria

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    The study was conducted to analyze the agricultural extension methods used in conflict resolution among agro – pastoralists in Adamawa State, Nigeria. A multi – stage random sampling technique was used to select 160 respondents who were administered interview schedules. Data were analyzed using descriptive statistics (frequencies and percentages) statistics and inferential (multiple regression) statistics. The study indicated that livestock destruction of farmlands was the major (50.63%) source of conflict among the respondents. The results revealed that the major (55.0%) source of conflict resolution among the respondents was community leaders in conflict resolutions. The study showed that truce was the most important type of conflict resolution used by respondents (59.38%). Majority (82.5%) of the respondents preferred face to face extension contact methods used for learning conflict resolution. All the positive significant relationship at 5% levels indicated that, an increase in each of these extension methods is likely to increase in conflict resolutions among agro – pastoralists. The study recommended that extension working environment should be strengthened with motivational mechanism to achieve the desired impact on conflict resolution among agro – pastoralists in the study area. Key words: Sources of conflict, Conflict Resolution and Agro – Pastoralists, Adamawa State, Nigeri

    Effect of Dynamic Voltage Restorer in Compensating for Voltage Sag and Controlling Harmonics in a Power Distribution System using Fumman Industry as a Case Study

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    Different power quality surveys done by researchers identify voltage sags as the most serious power quality problems for industrial customers. Voltage sag can cause serious problems to electric loads that cannot withstand variation in voltage such as adjustable speed drives, process control equipment and computers. This research work investigated the effect of Dynamic Voltage Restorer (DVR) in compensating for voltage sag and controlling harmonics in a power distribution system. A DVR is a power electronic converter base device that is used to regulate the voltage at the load terminals from various power quality problems like sag, swell unbalance etc in the supply voltage. The mathematical equations representing voltage sag and it compensation are presented. To implement the effect of DVR on industrial load network, Fumman Industry was considered as a case study. The DVR was modeled by building the subsystem of each major component. The components are injection transformer, fuzzy logic controller, battery and Pulse Width Modulation (PWM) inverter. Optimization technique was used to determine the appropriate battery size. Simulation was done without and with the DVR using Matlab/Simulink; under three and double phase line-to-ground faults.Simulation results showed that the modeled DVR can work very well against balanced and unbalanced voltage sag caused by fault in industrial distribution systemconsidering the harmonic limits

    Nurse-led implementation of ETAT plus is associated with reduced mortality in a children's hospital in Freetown, Sierra Leone

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    BACKGROUND: In the wake of the Ebola virus disease (EVD) epidemic in Sierra Leone, secondary care facilities faced an increase in admissions with few members of medical staff available to assess and treat patients. This led to long waiting times in hospital outpatient departments. The study was undertaken in the outpatient department of Ola During Children’s Hospital (the tertiary paediatric hospital for Sierra Leone) in the period immediately following the EVD epidemic of 2014–2015. AIMS: This retrospective analysis of operational programme data aimed to assess whether a quality-improvement approach and task-sharing between medical and nursing staff improved the quality of triage and the timeliness of care. METHODS: All staff working in the outpatient department were offered a 4-week training course, followed by on-the-job supervision and support for 6 months. Nurses who successfully completed the course were given responsibility for the initial assessment of sick patients and for prescribing and giving initial treatment. Data were collected at three points: before intervention and at 3 and 6 months after initiation of the intervention. All children presenting to the hospital for medical attention between 0800 and 1400 Monday to Friday were included. Triage assessment by the outpatient nurse was compared to that made by a clinically experienced observer, and the time taken for each child to be triaged, assessed and given initial treatment was recorded. RESULTS:Between months 0 and 6 of the intervention, detection of emergency signs by the triage nurse improved from 30% to 100%, and detection of priority signs improved from 34% to 100%. For children presenting with emergency signs, the median time between triage and full assessment improved from 57 minutes before intervention to 17 minutes at 3 months and 5 minutes at 6 months (p < 0.0005). For the same group, median time between triage and first antibiotic or antimalarial treatment improved from 220 minutes before intervention to 40 minutes at 3 months and 18 minutes at 6 months (p = 0.006). CONCLUSION: The results indicate that, with appropriate training and support, extending the emergency assessment and treatment of sick children to nursing staff in West African hospitals may improve the accuracy of triage and the time to assessment and treatment of children presenting with signs of serious illness

    Effects of copper overload on hepatic lipid peroxidation and antioxidant defense in rats

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    The influence of copper (Cu) overload on hepatic lipid peroxidation and antioxidation defense capacity was studied by overloading rats with copper sulphate orally (500 mg Cu/kg bw) 5 d/w for 8 w. Malondialdehyde (MDA), Cu-Zn superoxide dismutase (SOD), and Se-glutathione peroxidase (GSH-Px) were measured in serum and liver homogenate at 2, 4 and 8 w of dosing. Liver Cu concentration and alanine aminotransferase (ALT) activity were also determined. As Cu loading progressed, there were multiparameter changes with significant ALT elevation, increased MDA concentrations in serum and liver homogenate, and dramatic declines of SOD and GSH-Px activities in erythrocytes and whole blood respectively, along with marked elevation of hepatic Cu in the Cu-dosed group. Excessive Cu accumulation in the liver depressed SOD and GSH-Px activities and resulted in high MDA in serum and liver homogenate due to the lipid peroxidation induced by the Cu overload

    Burn Area Processing to Generate False Alarm Data for Hotspot Prediction Models

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    Developing hotspot prediction models using decision tree algorithms require target classes to which objects in a dataset are classified.  In modeling hotspots occurrence, target classes are the true class representing hotspots occurrence and the false class indicating non hotspots occurrence.  This paper presents the results of satellite image processing in order to determine the radius of a hotspot such that random points are generated outside a hotspot buffer as false alarm data.  Clustering and majority filtering were performed on the Landsat TM image to extract burn scars in the study area i.e. Rokan Hilir, Riau Province Indonesia.  Calculation on burn areas and FIRMS MODIS fire/hotspots in 2006 results the radius of a hotspot 0.90737 km.  Therefore, non-hotspots were randomly generated in areas that are located 0.90737 km away from a hotspot. Three decision tree algorithms i.e. ID3, C4.5 and extended spatial ID3 have been applied on a dataset containing 235 objects that have the true class and 326 objects that have the false class. The results are decision trees for modeling hotspots occurrence which have the accuracy of 49.02% for the ID3 decision tree, 65.24% for the C4.5 decision tree, and 71.66% for the extended spatial ID3 decision tree

    Assessment of regulation compliance and quality of sachet water factories In Ibadan North Local Government, Oyo State, Nigeria

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    Provision of clean drinking water is one of the basic human necessities for healthy livelihood. In Nigeria, many people relied on sachet waters as an alternative source of clean drinking water. However, complaints abound regarding lack of proper water quality standard being used which is a major health concern. This study assessed the regulatory compliance of some sachet water production companies and water quality standard in Ibadan North Local Government Area, Oyo State, Nigeria. Questionnaires were administered on factory’s organisational structure and staffing; facilities and equipment; water treatment processes and sanitation practices, Also, Sachet water samples were analysed for the contaminants of Turbidity, Colour, Odour, pH, Nitrate, Chloride, Iron, Electrical conductivity and E-coli count. From the questionnaire analysis, the adherence level with the regulations was poor as majority (60%) of the sachet water factories have poor organisational structure and only 33% have adequate facilities and equipment. However, water quality analysis showed that most of the sachet water parameters tested were within the standard range except for pH values and E Coli count which majority (70%) falls below standard for both. The study concludes that most sachet water brands produced are unsafe for human consumption. There is need for proper monitoring by relevant agencies towards ensuring sachet water factories continuously complied with standard operations for better public health in the study area

    Effect of Chemically Modified Banana Fibers on the Mechanical Properties of Poly-Dimethyl-Siloxane-Based Composites

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    The study presents the mechanical properties of polymer-based composites reinforced with chemically modified banana fibers, by alkalization in different concentrations of sodium hydroxide (NaOH). The fiber weight fraction has a great effect on the mechanical properties of the composites. Stiff composites were obtained at 6 wt% fiber fractions with Young’s modulus of 254.00 ±12.70 MPa. Moreover, the yield strength was 35.70 ±1.79 MPa at 6 wt% fiber fractions. However, the ultimate tensile strength (UTS) and toughness of the composites were obtained at 5 wt% fiber fractions. Statistical analyses were used to ascertain the significant different on the mechanical properties of the fibers and composites. The implication of the results is then discussed for potential applications of PDMS-based composites reinforced with chemically modified banana fibers
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