994 resultados para 100 ka cycles


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Introduction The importance of in vitro biomechanical testing in today’s understanding of spinal pathology and treatment modalities cannot be stressed enough. Different studies have used differing levels of dissection of their spinal segments for their testing protocols[1, 2]. The aim of this study was to assess the impact of removing the costovertebral joints and partial resection of the spinous process sequentially, on the stiffness of the immature thoracic bovine spinal segment. Materials and Methods Thoracic spines from 6-8 week old calves were used. Each spine was dissected and divided into motion segments with 5cm of attached rib on each side and full spinous processes including levels T4-T11 (n=28). They were potted in polymethylemethacrylate. An Instron Biaxial materials testing machine with a custom made jig was used for testing. The segments were tested in flexion/extension, lateral bending and axial rotation at 37⁰C and 100% humidity, using moment control to a maximum 1.75 Nm with a loading rate of 0.3 Nm per second. They were first tested intact for ten load cycles with data collected from the tenth cycle. Progressive dissection was performed by removing first the attached ribs, followed by the spinous process at its base. Biomechanical testing was carried out after each level of dissection using the same protocol. Statistical analysis of the data was performed using repeated measures ANOVA. Results In combined flexion/extension there was a significant reduction in stiffness of 16% (p=0.002). This was mainly after resection of the ribs (14%, p=0.024) and mainly occurred in flexion where stiffness reduced by 22% (p=0.021). In extension, stiffness dropped by 13% (p=0.133). However there was no further significant change in stiffness on resection of the spinous process (<1%) (p=1.00). In lateral bending there was a significant decrease in stiffness of 13% (p<0.001). This comprised a drop of 11% on resection of the ribs (p=0.009) and a further 8% on resection of the spinous process (p=0.014). There was no difference between left and right bending. In axial rotation there was no significant change in stiffness after each stage of dissection (p=0.253). There was no difference between left and right rotation. Conclusion The costovertebral joints play a significant role in providing stability to the bovine thoracic spine in both flexion/extension and lateral bending, whereas the spinous processes play a minor role. Both elements have little effect on axial rotation stability.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Using a multiple plasma deposition-annealing (MDA) technique, we have fabricated an Au nanoisland-based thin film nanoresistor with a very low temperature coefficient of electrical resistivity in a cryogenic-to-room temperature range of 10 to 300 K. The nanoislanded gold film was deposited on a SiO2/Si wafer (500 nm SiO2 thickness) between two 300 nm thick Au electrodes which were separated by 100 m. A sophisticated selection of the thickness of the nanoislanded gold film, the annealing temperature, as well as the number of deposition/annealing cycles resulted in the fabrication of a nanoresistor with a temperature coefficient of electrical resistivity of 2.1 × 10-3 K-1 and the resistivity deviation not exceeding 2% in a cryogenic-to-room temperature range. We have found that the constant resistivity regime of the nanoisland-based thin film nanoresistor corresponds to a minimized nanoisland activation energy (approximately 0.3 meV). This energy can be minimized by reducing the nearest neighbor distance and increasing the size of the Au nanoislands in the optimized nanoresistor structure. It is shown that the constant resistivity nanoresistor operates in the regime where the thermally activated electron tunneling is compensated by the negative temperature dependence of the metallic-type conductivity of nanoislands. Our results are relevant to the development of commercially viable methods of nanoresistor production for various nanoelectronics-based devices. The proposed MDA technique also provides the opportunity to fabricate large arrays of metallic nanoparticles with controllable size, shapes and inter-nanoparticle gaps.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The results of the combined experimental and numerical study suggest that nonequilibrium plasma-driven self-organization leads to better size and positional uniformity of nickel nanodot arrays on a Si(100) surface compared with neutral gas-based processes under similar conditions. This phenomenon is explained by introducing the absorption zone patterns, whose areas relative to the small nanodot sizes become larger when the surface is charged. Our results suggest that strongly nonequilibrium and higher-complexity plasma systems can be used to improve ordering and size uniformity in nanodot arrays of various materials, a common and seemingly irresolvable problem in self-organized systems of small nanoparticles. © 2008 American Institute of Physics.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Introduction Intervertebral stapling is a leading method of fusionless scoliosis treatment which attempts to control growth by applying pressure to the convex side of a scoliotic curve in accordance with the Hueter-Volkmann principle. In addition to that, staples have the potential to damage surrounding bone during insertion and subsequent loading. The aim of this study was to assess the extent of bony structural damage including epiphyseal injury as a result of intervertebral stapling using an in vitro bovine model. Materials and Methods Thoracic spines from 6-8 week old calves were dissected and divided into motion segments including levels T4-T11 (n=14). Each segment was potted in polymethylemethacrylate. An Instron Biaxial materials testing machine with a custom made jig was used for testing. The segments were tested in flexion/extension, lateral bending and axial rotation at 37⁰C and 100% humidity, using moment control to a maximum 1.75 Nm with a loading rate of 0.3 Nm per second for 10 cycles. The segments were initially tested uninstrumented with data collected from the tenth load cycle. Next an anterolateral 4-prong Shape Memory Alloy (SMA) staple (Medtronic Sofamor Danek, USA) was inserted into each segment. Biomechanical testing was repeated as before. The staples were cut in half with a diamond saw and carefully removed. Micro-CT scans were performed and sagittal, transverse and coronal reformatted images were produced using ImageJ (NIH, USA).The specimens were divided into 3 grades (0, 1 and 2) according to the number of epiphyses damaged by the staple prongs. Results: There were 9 (65%) segments with grade 1 staple insertions and 5 (35%) segments with grade 2 insertions. There were no grade 0 staples. Grade 2 spines had a higher stiffness level than grade 1 spines, in all axes of movement, by 28% (p=0.004). This was most noted in flexion/extension with an increase of 49% (p=0.042), followed by non-significant change in lateral bending 19% (p=0.129) and axial rotation 8% (p=0.456) stiffness. The cross sectional area of bone destruction from the prongs was only 0.4% larger in the grade 2 group compared to the grade 1 group (p=0.961). Conclusion Intervertebral staples cause epiphyseal damage. There is a difference in stiffness between grade 1 and grade 2 staple insertion segments in flexion/extension only. There is no difference in the cross section of bone destruction as a result of prong insertion and segment motion.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Particle emission measurements from a fleet of 14 CNG and 5 Diesel buses were measured both for transient and steady state mode s on a chassis dynamometer with a CVS dilution system. Several transient DT80 cycles and 4 steady sate modes (0, 25, 50 100% of maximum load) were measured for each bus tested. Particle number concentration data was collected by three CPC’s (TSI 3022, 3010 3782WCPC) having D50 cut-offs set to 5, 10 and 20nm respectively. The size distributions were measured with a TSI 3080 SMPS with a 3025 CPC during the steady state modes. Particle mass emissions were measured with a TSI Dustrak. Particle mass emissions for Diesel buses were upto 2 orders of magnitude higher than for CNG buses. Particle number emissions during steady state modes for Diesel busses were 2 to 5 times higher than for CNG busses for all of the tested loads. On the other hand for the DT80 transient cycle particle number emissions were up to 3 times higher for the CNG buses. More detailed analysis of the transient cycles revealed that the reason for this was due to high particle number emissions from CNG busses during the acceleration parts of the cycles. Particles emitted by the CNG busses during acceleration were in the nucleation mode with the majority being smaller than 10nm. Volatility measurements have also shown that they were highly volatile.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

12 Original recordings curated by leading national industry figures. It’s a 12 track album full of remixed, rerecorded and rejigged tracks from the project that were shortlisted by our friends at MGM Distribution, Music Sales, and EMI Music Australia. The TWELVE album is already receiving critical acclaim from Australia's music industry.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Eleven original recordings curated by leading industry figures. This is a compilation album from QUT's 2012 100 Songs project. It's called Eleven: Best of 100 Songs Project 2012 and was released in May 2013. It’s an 11 track album with a bonus track, full of remixed, rerecorded and rejigged tracks from the project that were shortlisted by our friends at MGM Distribution, Mushroom Music, Island Records and Music Sales Australia. The Eleven album is already receiving critical acclaim from Australia's music industry.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The Independent Music Project is centred around the development and creation of new music, and includes research into copyright, business models of the future, new technologies, and new audiences. The music industry is undergoing the most radical changes it has faced in almost a century. New digital technologies have made the production, distribution, and promotion of recorded music accessible to anyone with a personal computer. People can now make high-quality digital copies of music and distribute them globally within minutes. Even bastions of the established industries, such as EMI and Columbia, are struggling to make sense of the new industry terrain. The whole employment picture has changed just as radically for people who wish to make a living from music. In Australia, many of the avenues that provided employment for musicians have either disappeared or dramatically shrunk. The advertising industry no longer provides the level of employment it used to prior to the Federal deregulation of the industry in 1992. In many places, new legislative pressures on inner-city and suburban venues have diminished the number of performance spaces that musicians can work in. Just as quickly, new sectors have opened to professional musicians: computer games, ringtones, sound-enabled toys and web advertising all present new opportunities to the enterprising musician. The opportunity to distribute music internationally without being signed to a major label is very attractive to many aspiring and established professionals. No doubt the music industry will face many more challenges as technologies continue to change, as global communication gets easier and faster, and as the challenges to copyright proliferate and change. These challenges cannot be successfully met on a single front. They require research and expertise from all sectors being affected, and this is why the independent music project (IMP) exists.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The Independent Music Project is centred around the development and creation of new music, and includes research into copyright, business models of the future, new technologies, and new audiences. The music industry is undergoing the most radical changes it has faced in almost a century. New digital technologies have made the production, distribution, and promotion of recorded music accessible to anyone with a personal computer. People can now make high-quality digital copies of music and distribute them globally within minutes. Even bastions of the established industries, such as EMI and Columbia, are struggling to make sense of the new industry terrain. The whole employment picture has changed just as radically for people who wish to make a living from music. In Australia, many of the avenues that provided employment for musicians have either disappeared or dramatically shrunk. The advertising industry no longer provides the level of employment it used to prior to the Federal deregulation of the industry in 1992. In many places, new legislative pressures on inner-city and suburban venues have diminished the number of performance spaces that musicians can work in. Just as quickly, new sectors have opened to professional musicians: computer games, ringtones, sound-enabled toys and web advertising all present new opportunities to the enterprising musician. The opportunity to distribute music internationally without being signed to a major label is very attractive to many aspiring and established professionals. No doubt the music industry will face many more challenges as technologies continue to change, as global communication gets easier and faster, and as the challenges to copyright proliferate and change. These challenges cannot be successfully met on a single front. They require research and expertise from all sectors being affected, and this is why the independent music project (IMP) exists.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The Independent Music Project is centred around the development and creation of new music, and includes research into copyright, business models of the future, new technologies, and new audiences. The music industry is undergoing the most radical changes it has faced in almost a century. New digital technologies have made the production, distribution, and promotion of recorded music accessible to anyone with a personal computer. People can now make high-quality digital copies of music and distribute them globally within minutes. Even bastions of the established industries, such as EMI and Columbia, are struggling to make sense of the new industry terrain. The whole employment picture has changed just as radically for people who wish to make a living from music. In Australia, many of the avenues that provided employment for musicians have either disappeared or dramatically shrunk. The advertising industry no longer provides the level of employment it used to prior to the Federal deregulation of the industry in 1992. In many places, new legislative pressures on inner-city and suburban venues have diminished the number of performance spaces that musicians can work in. Just as quickly, new sectors have opened to professional musicians: computer games, ringtones, sound-enabled toys and web advertising all present new opportunities to the enterprising musician. The opportunity to distribute music internationally without being signed to a major label is very attractive to many aspiring and established professionals. No doubt the music industry will face many more challenges as technologies continue to change, as global communication gets easier and faster, and as the challenges to copyright proliferate and change. These challenges cannot be successfully met on a single front. They require research and expertise from all sectors being affected, and this is why the independent music project (IMP) exists.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The Independent Music Project is centred around the development and creation of new music, and includes research into copyright, business models of the future, new technologies, and new audiences. The music industry is undergoing the most radical changes it has faced in almost a century. New digital technologies have made the production, distribution, and promotion of recorded music accessible to anyone with a personal computer. People can now make high-quality digital copies of music and distribute them globally within minutes. Even bastions of the established industries, such as EMI and Columbia, are struggling to make sense of the new industry terrain. The whole employment picture has changed just as radically for people who wish to make a living from music. In Australia, many of the avenues that provided employment for musicians have either disappeared or dramatically shrunk. The advertising industry no longer provides the level of employment it used to prior to the Federal deregulation of the industry in 1992. In many places, new legislative pressures on inner-city and suburban venues have diminished the number of performance spaces that musicians can work in. Just as quickly, new sectors have opened to professional musicians: computer games, ringtones, sound-enabled toys and web advertising all present new opportunities to the enterprising musician. The opportunity to distribute music internationally without being signed to a major label is very attractive to many aspiring and established professionals. No doubt the music industry will face many more challenges as technologies continue to change, as global communication gets easier and faster, and as the challenges to copyright proliferate and change. These challenges cannot be successfully met on a single front. They require research and expertise from all sectors being affected, and this is why the independent music project (IMP) exists.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This presentation tells the story of an initiative in middle schooling at Kelvin Grove State College that begins in the Art studios, but reaches out to other disciplines and approaches, and to community and industry partners. It is inspired by the potential of 'future thinking' to become a compelling focus in contemporary art and design. Ethically it espouses a simple premise": every student in our classrooms now has a stake in creating livable, democratic and creative futures. Every student has the potential to be an active force in making that future. "100 Futures Now" is a project that envisages creative and imaginative students working in collaboration with artists and designers to visualize amazing futures and communicate their vision through art and design. "100 Futures Now" is one in a series of innovative curriculum initiatives at Kelvin Grove State College designed to build sustainable practice in arts education with the support of partners in industry and universities and with resident artists and designers. The model blends elements of art and design methodology to focus on the critical and creative thinking skills prioritised in ACARA and 21st century curriculum. The organisers are developing a sustainable model for working with resident artists that goes beyond a single arts intervention or extension/enrichment experience. In this model artists and designers are collaborators in the design of learning experiences that support future programs. This model also looks to transfer the benefits of residencies to the wider school community (in this case to middle schooling curriculum) and to teachers in other curriculum areas, and not exclusively to the immediate target group. In "100 Futures Now", story-making is the engine that powers the creative process. For this reason the program uses a series of imaginative scenarios, including those of speculative fiction and science, as departure points for inquiry, and applies the methodologies of arts and design practice to explore and express student story telling and story making. The story-making responses of student teams will naturally be expressed multimodally through visual art, design artifacts, installation, performance and digital works. The project’s focus on narratives and its modes of communication (performance/installation) are inspired by the work of experimental contemporary design practices and the speculative scenarios of U.K. based designers Anthony Dunne and Fiona Raby. Thanks to the support of an Arts Queensland Artist-in -Residence grant in 2014, resident artists and designers who work with a diversity of ideas and approaches ranging over science, bio-ethics, biodiversity, behavior and ethics, ambient sound, urbanism, food, and wearable design, will work with middle school students as catalysts for deeper thinking and creative action. All these rich fields for future speculation will become triggers for team inquiry into the deeper connections between the past, the present, and future challenges such as climate, waste, energy, sustainability and resilience. These imagined futures will form the platform for a critical, sustainability/design futures approach that will involve questioning assumptions and empowering students as agents rather than consumers of change.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The aluminum (Al) doped polycrystalline p-type β-phase iron disilicide (p-β-FeSi2) is grown by thermal diffusion of Al from Al-passivated n-type Si(100) surface into FeSi2 during crystallization of amorphous FeSi2 to form a p-type β-FeSi 2/n-Si(100) heterostructure solar cell. The structural and photovoltaic properties of p-type β-FeSi2/n-type c-Si structures is then investigated in detail by using X-ray diffraction, Raman spectroscopy, transmission electron microscopy analysis, and electrical characterization. The results are compared with Al-doped p-β-FeSi2 prepared by using cosputtering of Al and FeSi2 layers on Al-passivated n-Si(100) substrates. A significant improvement in the maximum open-circuit voltage (Voc) from 120 to 320 mV is achieved upon the introduction of Al doping through cosputtering of Al and amorphous FeSi2 layer. The improvement in Voc is attributed to better structural quality of Al-doped FeSi2 film through Al doping and to the formation of high quality crystalline interface between Al-doped β-FeSi2 and n-type c-Si. The effects of Al-out diffusion on the performance of heterostructure solar cells have been investigated and discussed in detail.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The properties of CdS nanoparticles incorporated onto mesoporous TiO2 films by a successive ionic layer adsorption and reaction (SILAR) method were investigated by Raman spectroscopy, UV-visible spectroscopy, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). High resolution TEM indicated that the synthesized CdS particles were hexagonal phase and the particle sizes were less than 5 nm when SILAR cycles were fewer than 9. Quantum size effect was found with the CdS sensitized TiO2 films prepared with up to 9 SILAR cycles. The band gap of CdS nanoparticles decreased from 2.65 eV to 2.37 eV with the increase of the SILAR cycles from 1 to 11. The investigation of the stability of the CdS/TiO2 films in air under illumination (440.6 µW/cm2) showed that the photodegradation rate was up to 85% per day for the sample prepared with 3 SILAR cycles. XPS analysis indicated that the photodegradation was due to the oxidation of CdS, leading to the transformation from sulphide to sulphate (CdSO4). Furthermore, the degradation rate was strongly dependent upon the particle size of CdS. Smaller particles showed faster degradation rate. The size-dependent photo-induced oxidization was rationalized with the variation of size-dependent distribution of surface atoms of CdS particles. Molecular Dynamics (MD) simulation has indicated that the surface sulphide anion of a large CdS particle such as CdS made with 11 cycles (CdS11, particle size = 5.6 nm) accounts for 9.6% of the material whereas this value is increased to 19.2% for (CdS3) based smaller particles (particle size: 2.7 nm). Nevertheless, CdS nanoparticles coated with ZnS material showed a significantly enhanced stability under illumination in air. A nearly 100% protection of CdS from photon induced oxidation with a ZnS coating layer prepared using four SILAR cycles, suggesting the formation of a nearly complete coating layer on the CdS nanoparticles.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Objectives This study aims to develop a better understanding of mothers’ knowledge, understanding, and attitude towards children’s measles immunization and explore the relationship between mothers’ understanding of measles immunization and health promotion programs in North Vietnam. Methods Semi-structured interviews were conducted with 15 mothers of children aged 1 or 6 years old between 2006 and 2010 in two provinces in North Vietnam. Ten interviews were transcribed and analysed to explore themes while other five interviews were cross-referenced for congruency. Among the ten mothers whose interviews were analysed, there were five mothers whose children received the full measles immunization schedule (two doses) and five mothers whose children received one or none of measles vaccination. Results Mothers had different levels of understanding and a strong positive attitude towards measles immunization. Mothers considered health officers at the commune health centres who played an important role in the promotion of measles immunization, as the main source of information. The relationship between the mother’s understanding about measles immunization and health promotion programs was found to be both positive and negative. Conclusion Mothers whose children received the full measles immunization schedule paid more attention to measles immunization and health promotion programs compared with mothers whose children received one or none of measles vaccination. Mothers’ misunderstanding about the measles immunization schedule was the main reason for choosing not to receive the measles immunizations. These findings help to improve communication with mothers about measles immunization and close the gap for 100% measles immunization in North Vietnam.