776 research outputs found
Experimental Study of acoustic characteristics of expansion chamber with mean flow
No full textFor the measurement of transmission loss of the silencers which have mean flow, the noise levels of signals depicted by microphone usually prohibit accurate measurements of the transmission loss. To overcome this difficulty, static pressure compensation technique has been developed to increase the dynamic range of the microphones, resulting accurate measurement of transmission loss in the presence of high noise level. Series of experiments to investigate the acoustic characteristics of expansion chamber with mean flow has been performed using the pressure compensated microphones. Results demonstrate: (1) frequency shift due to the presence of mean flow, (2) effect of length, diameter, offset length and twisting angles to the transmission loss of expansion chamber with and without mean flow(up to 50m/sec), (3) relation between the proposed parameter aspect ratio and number of peaks of transmission loss in low frequency region
Synthesis and thin-film transistor performance of fluorene-based copolymers containing thiophene moieties having different position of alkyl side chain
No full text
Copper/Molding Compound Interfacial Delamination
No full textDelamination at the resin-copper interface is fully
investigated by adopting experimental and numerical
techniques. Due to the heterogeneous nature of the molding
compound, a complete microscopic assessment is necessary to
understand its impact on macroscopic mechanical and adhesion
properties. Starting from microstructure morphology, inverse
homogenization scheme is employed to derive polymer elastic
features from experimental data relevant to the resin. Fracture
tests are adopted to describe the response of the interface
between the two materials. Microstructural effects on adhesion
are studied with micro-scale models of the copper-polymerfiller
system, accounting for adhesion through a cohesive
approach. The effects of filler content changes, substrate
surface roughness, and intrinsic experimental adhesive
parameters on the effective traction-separation law are
successfully assessed. Finally, the promising findings are
beneficial to analyze the interface damage propagation during
package-oriented reliability tests and may be employed to
investigate such interfaces in microelectronic plastic packages
A systematic review of epidemiological studies on the prevalence of complementary and alternative medicine (CAM) use by paediatric cancer patients. Presented at ECIM 2008.
No full textBackground: paediatric cancer patients are likely to use complementary and alternative medicines (CAMs) alongside more conventional interventions. A number of individual studies have been carried out to examine prevalence rates of CAM use amongst paediatric cancer patients. These studies have varied findings and are of mixed quality. This meta-analytic review therefore aimed to assess the quality of this literature and to determine what is known about the prevalence of the CAM use in paediatric cancer. Secondary research questions focused on the types of CAM used, trends in CAM use over time, reasons for CAM use, and demographic characteristics associated with CAM use.Method: electronic and manual searches for relevant studies identified 26 English language journal articles of primary research studies investigating the prevalence of CAM usage among paediatric cancer patients in peer-reviewed journals. A quality assessment checklist was rigorously developed based on the strengthening the reporting of observational studies in epidemiology (STROBE) statement in collaboration with Dr. Erik von Elm (lead author of the STROBE statement). Data were extracted and validated by more than one author and analysed using meta-analytic techniques.Results: the prevalence of CAM use by paediatric cancer patients ranged from 40% to 53%. The quality of the studies was mixed and did not correlate with the estimated prevalence of CAM use. ‘Herbals’ was the most popular CAM modality. Paediatric cancer patients use CAM for various reasons. Higher level of education and income were associated with CAM use in North America; the opposite was true for CAM use in Mexico and Turkey.Conclusion: a substantial proportion of paediatric cancer patients use CAM. There is a need to use standardised definitions of the CAM in future studies to generate comparable data. The quality assessment checklist has potential to be a useful quality assessment instrument for other reviews of similar epidemiological studie
Computer-aided-design and manufacture of optical multilayer filters
No full textSIGLEAvailable from British Library Document Supply Centre- DSC:D66600/86 / BLDSC - British Library Document Supply CentreGBUnited Kingdo
Microchip electrophoresis for UVC-induced DNA damage assessment
No full textIn this thesis a design is presented which main objectives are to improve the speed, sensitivity and resolution of the commonly used gel electrophoresis method. To this end a background study is performed to look at the differences and similarities between both gel and micro-chip electrophoresis. Based on these findings some calculations are done to see if the expected design can theoretically improve in the above mentioned fields. A design is created and later fabricated in order to obtain these objectives. For the design a glass substrate is used with integrated electrodes, combined with a PMT sensor system to process the signals from the chip via a computer program. The main techniques used for the fabrication are wet etching and wafer bonding. The testing results produce a clear signal, which shows improvements in sensitivity and resolution, as well as producing results in less than three minutes.Microelectronics & Computer EngineeringElectrical Engineering, Mathematics and Computer Scienc
- …
