966 resultados para Laboratory test


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Energy efficient lubricants are becoming increasingly popular. This is due to a global increase in environmental awareness combined with the potential of reducing operating costs. A new test method of evaluating the energy efficiency of gear oils has been described in this report. The method involves measuring the power required by an FZG test rig to run while using a particular test lubricant. For each oil that was being evaluated, the rig was run for 10 minutes at a load stage of 10. Six extreme pressure (EP) industrial gear oils of mineral base were tested. The difference in power requirements between the best and the worst performing oils was 2.77 and 3.24 kW, respectively. This equates to a 14.6% reduction in power, a significant amount if considered in relation to a high powered industrial machine. The oils of superior performance were noticed to run at reduced temperatures. They were also more expensive than the other products of lesser performance.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Tested D. J. Kavanagh's (1983) depression model's explanation of response to cognitive-behavioral treatment among 19 20–60 yr old Ss who received treatment and 24 age-matched Ss who were assigned to a waiting list. Measures included the Beck Depression Inventory and self-efficacy (SE) and self-monitoring scales. Rises in SE and self-monitored performance of targeted skills were closely associated with the improved depression scores of treated Ss. Improvements in the depression of waiting list Ss occurred through random, uncontrolled events rather than via a systematic increase in specific skills targeted in treatment. SE regarding assertion also predicted depression scores over a 12-wk follow-up.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Teaching to an international audience online can be significantly different as compared to a traditional classroom setting. In a traditional classroom setting, the students are usually removed from their own cultural context and required to operate in the lecturer’s context. International students coming to Malaysia to study are implicitly expected to, and often do, become familiar with the Malaysian culture and style of education. The use of educational technologies as a blended strategy in higher education programs offers challenges and opportunities for all students but this may be different for international students who come from varied backgrounds. With an increasingly competitive global demand for higher education, Malaysian institutions strive to be the hub of educational excellence and a preferred option for international students in coping with the challenges of studying abroad in a different culture. This research will evaluate how undergraduate students perceive their online learning experiences in a Malaysian university. The OLES (Online Learning Environment Survey) will be used to explore the international and domestic students’ perception on e-learning and the findings of the first six OLES scales varying from (Computer Usage, Teacher Support, Student Interaction & Collaboration, Personal Relevance, Authentic Learning, and Student Autonomy) will be reported in this research. An in-depth study will be conducted to compare and contrast the challenges of international students with domestic students. Major difficulties encountered and how these students actually cope with e-learning, as well as the strategies and tools used to overcome the challenges will be investigated.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Teaching to an international audience online can be significantly different as compared to a traditional classroom setting. In a traditional classroom setting, the students are usually removed from their own cultural context and required to operate in the lecturer’s context. International students coming to Malaysia to study are implicitly expected to, and often do, become familiar with the Malaysian culture and style of education. The use of educational technologies as a blended strategy in higher education programs offers challenges and opportunities for all students but this may be different for international students who come from varied backgrounds. With an increasingly competitive global demand for higher education, Malaysian institutions strive to be the hub of educational excellence and a preferred option for international students in coping with the challenges of studying abroad in a different culture. This research will evaluate how undergraduate students perceive their online learning experiences in a Malaysian institute. The OLES (Online Learning Environment Survey) will be used to explore the international and domestic students’ perception on e-learning and the findings of the last six OLES scales varying from (Equity, Enjoyment, Asychronocity, Evaluation & Assessments, Online Learning Tools, and Interface Design) will be reported in this research. An in-depth study will be conducted to compare and contrast the challenges of international students with domestic students. Major difficulties encountered and how these students actually cope with e-learning, as well as the strategies and tools used to overcome the challenges will be investigated.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Heart disease is attributed as the highest cause of death in the world. Although this could be alleviated by heart transplantation, there is a chronic shortage of donor hearts and so mechanical solutions are being considered. Currently, many Ventricular Assist Devices (VADs) are being developed worldwide in an effort to increase life expectancy and quality of life for end stage heart failure patients. Current pre-clinical testing methods for VADs involve laboratory testing using Mock Circulation Loops (MCLs), and in vivo testing in animal models. The research and development of highly accurate MCLs is vital to the continuous improvement of VAD performance. The first objective of this study was to develop and validate a mathematical model of a MCL. This model could then be used in the design and construction of a variable compliance chamber to improve the performance of an existing MCL as well as form the basis for a new miniaturised MCL. An extensive review of literature was carried out on MCLs and mathematical modelling of their function. A mathematical model of a MCL was then created in the MATLAB/SIMULINK environment. This model included variable features such as resistance, fluid inertia and volumes (resulting from the pipe lengths and diameters); compliance of Windkessel chambers, atria and ventricles; density of both fluid and compressed air applied to the system; gravitational effects on vertical columns of fluid; and accurately modelled actuators controlling the ventricle contraction. This model was then validated using the physical properties and pressure and flow traces produced from a previously developed MCL. A variable compliance chamber was designed to reproduce parameters determined by the mathematical model. The function of the variability was achieved by controlling the transmural pressure across a diaphragm to alter the compliance of the system. An initial prototype was tested in a previously developed MCL, and a variable level of arterial compliance was successfully produced; however, the complete range of compliance values required for accurate physiological representation was not able to be produced with this initial design. The mathematical model was then used to design a smaller physical mock circulation loop, with the tubing sizes adjusted to produce accurate pressure and flow traces whilst having an appropriate frequency response characteristic. The development of the mathematical model greatly assisted the general design of an in vitro cardiovascular device test rig, while the variable compliance chamber allowed simple and real-time manipulation of MCL compliance to allow accurate transition between a variety of physiological conditions. The newly developed MCL produced an accurate design of a mechanical representation of the human circulatory system for in vitro cardiovascular device testing and education purposes. The continued improvement of VAD test rigs is essential if VAD design is to improve, and hence improve quality of life and life expectancy for heart failure patients.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A laboratory scale twin screw extruder has been interfaced with a near infrared (NIR) spectrometer via a fibre optic link so that NIR spectra can be collected continuously during the small scale experimental melt state processing of polymeric materials. This system can be used to investigate melt state processes such as reactive extrusion, in real time, in order to explore the kinetics and mechanism of the reaction. A further advantage of the system is that it has the capability to measure apparent viscosity simultaneously which gives important additional information about molecular weight changes and polymer degradation during processing. The system was used to study the melt processing of a nanocomposite consisting of a thermoplastic polyurethane and an organically modified layered silicate.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Aims: This study investigated the effect of simulated visual impairment on the speed and accuracy of performance on a series of commonly used cognitive tests. ----- Methods: Cognitive performance was assessed for 30 young, visually normal subjects (M=22.0yrs ± 3.1 yrs) using the Digit Symbol Substitution Test (DSST), Trail Making Test (TMT) A and B and the Stroop Colour Word Test under three visual conditions: normal vision and two levels of visually degrading filters (VistechTM) administered in a random order. Distance visual acuity and contrast sensitivity were also assessed for each filter condition. ----- Results: The visual filters, which degraded contrast sensitivity to a greater extent than visual acuity, significantly increased the time to complete (p<0.05), but not the number of errors made, on the DSST and the TMT A and B and affected only some components of the Stroop test.----- Conclusions: Reduced contrast sensitivity had a marked effect on the speed but not the accuracy of performance on commonly used cognitive tests, even in young individuals; the implications of these findings are discussed.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Purpose. To investigate the functional impact of amblyopia in children, the performance of amblyopic and age-matched control children on a clinical test of eye movements was compared. The influence of visual factors on test outcome measures was explored. Methods. Eye movements were assessed with the Developmental Eye Movement (DEM) test, in a group of children with amblyopia (n = 39; age, 9.1 ± 0.9 years) of different causes (infantile esotropia, n = 7; acquired strabismus, n = 10; anisometropia, n = 8; mixed, n = 8; deprivation, n = 6) and in an age-matched control group (n = 42; age, 9.3 ± 0.4 years). LogMAR visual acuity (VA), stereoacuity, and refractive error were also recorded in both groups. Results. No significant difference was found between the amblyopic and age-matched control group for any of the outcome measures of the DEM (vertical time, horizontal time, number of errors and ratio(horizontal time/vertical time)). The DEM measures were not significantly related to VA in either eye, level of binocular function (stereoacuity), history of strabismus, or refractive error. Conclusions. The performance of amblyopic children on the DEM, a commonly used clinical measure of eye movements, has not previously been reported. Under habitual binocular viewing conditions, amblyopia has no effect on DEM outcome scores despite significant impairment of binocular vision and decreased VA in both the better and worse eye.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Programs written in languages of the Oberon family usually contain runtime tests on the dynamic type of variables. In some cases it may be desirable to reduce the number of such tests. Typeflow analysis is a static method of determining bounds on the types that objects may possess at runtime. We show that this analysis is able to reduce the number of tests in certain plausible circumstances. Furthermore, the same analysis is able to detect certain program errors at compile time, which would normally only be detected at program execution. This paper introduces the concepts of typeflow analysis and details its use in the reduction of runtime overhead in Oberon-2.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A study among Australian college students gauged their reactions to a television commercial produced for the U.S. Commerce Department to bolster sagging tourism numbers among international visitors. In addition to using traditional measures applied to tourism advertisements, the student also concluded items to measure attitudes toward the U.S. government and its people Pre- and post-viewing results indicated that while the Hollywood-movie-themed commercial was not well received by the Australian students as a tourism message, it did result in more favorable attitudes toward the U.S. government, though not the U.S. people. The findings lend partial support for the potential of tourism advertising efforts to exert a "bleed-over effect" in terms of their contributions to overall attitudes toward a country, regardless of whether viewers plan to visit the country whose travel advertisements they see.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A study among Australian college students gauged their reactions to a television commercial produced for the US Commerce Department to bolster sagging tourism numbers among international visitors. In additional to using traditional measures applied to tourism advertisements, the study also included items to measure attitudes toward the US government and its people. Pre- and post-viewing results indicated that although the Hollywood-movie-themes commercial was not well received by the Australian students as a tourism message, it did result in more favourable attitudes toward the US government, although not the US people. The findings lend partial support for the potential of tourism advertising efforts to exert a 'bleed-over effect' in terms of their contribution to overall attitudes toward a country, regardless of whether viewers plan to visit the country whose travel advertisements of which they see.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The effects of sintering on several properties of FTO and ITO substates used in DSC have been investigated. FTO & ITO substrates were prepared with a range of sizes and aspect ratios - emulated laboratory style test cells through to prototype modules. Time and temperature of the sintering profiles were varied and sheet resistance and flatness measured. Electrical properties of the substrates were then further characterized by electrochemical impedance spectroscopy, and module sized devices were assembled and thickness variations over the device area were determined and related to performance.