Ion association and molar conductivity in polyether electrolytes

The ion association behaviour observed in our earlier studies of a polyether electrolyte system at elevated temperatures, was reminiscent of the molar conductivity behaviour typical of low dielectric constant systems. Further investigation of this relationship has led to some suggestions about the types of ionic species present in the polymer electrolyte systems. FT-IR spectroscopy has been used in this work to contrast ion association in an amorphous polyether electrolyte with two liquid electrolytes, N,N-dimethyl-formamide and tetraethylenegylcol dimethylether, containing lithium trifluoromethan sulfonate.

Long-term ethylene oxide exposure trends in US hospitals : relationship with OSHA regulatory and enforcement actions

We assessed long-term trends in ethylene oxide (EtO) worker exposures for the purposes of exposure surveillance and evaluation of the impacts of the Occupational Safety and Health Administration (OSHA) 1984 and 1988 EtO standards. We obtained exposure data from a large commercial vendor and processor of EtO passive dosimeters. Personal samples (87 582 workshift [8-hr] and 46 097 short-term [15-min] samples) from 2265 US hospitals were analyzed for time trends from 1984 through 2001 and compared with OSHA enforcement data. Exposures declined steadily for the first several years after the OSHA standards were set. Workshift exposures continued to taper off and have remained low and constant through 2001. However, since 1996, the probability of exceeding the short-term excursion limit has increased. This trend coincides with a decline in enforcement of the EtO standard. Results indicate the need for renewed intervention efforts to preserve gains made following the passage and implementation of the 1984 and 1988 EtO standards.

Photoreceptor topography and spectral sensitivity in the common brushtail possum (Trichosurus vulpecula)

Marsupials are believed to be the only non-primate mammals with both trichromatic and dichromatic color vision. The diversity of color vision systems present in marsupials remains mostly unexplored. Marsupials occupy a diverse range of habitats, which may have led to considerable variation in the presence, density, distribution, and spectral sensitivity of retinal photoreceptors. In this study we analyzed the distribution of photoreceptors in the common brushtail possum (Trichosurus vulpecula). Immunohistochemistry in wholemounts revealed three cone subpopulations recognized within two spectrally distinct cone classes. Long-wavelength sensitive (LWS) single cones were the largest cone subgroup (67-86%), and formed a weak horizontal visual streak (peak density 2,106 ± 435/mm2) across the central retina. LWS double cones were strongly concentrated ventrally (569 ± 66/mm2), and created a "negative" visual streak (134 ± 45/mm2) in the central retina. The strong regionalization between LWS cone topographies suggests differing visual functions. Short-wavelength sensitive (SWS) cones were present in much lower densities (3-10%), mostly located ventrally (179 ± 101/mm2). A minority population of cones (0-2.4%) remained unlabeled by both SWS- and LWS-specific antibodies, and may represent another cone population. Microspectrophotometry of LWS cone and rod visual pigments shows peak spectral sensitivities at 544 nm and 500 nm, respectively. Cone to ganglion cell convergences remain low and constant across the retina, thereby maintaining good visual acuity, but poor contrast sensitivity during photopic vision. Given that brushtail possums are so strongly nocturnal, we hypothesize that their acuity is set by the scotopic visual system, and have minimized the number of cones necessary to serve the ganglion cells for photopic vision.

Dielectric percolative composites with high dielectric constant and low dielectric loss based on sulfonated poly(aryl ether ketone) and a-MWCNTs coated with polyaniline

Acidified multi-walled carbon nanotubes (a-MWCNTs) coated with polyaniline (PANI) (a-MWCNTs@PANI) nanofiller were prepared by in situ polymerization. Novel dielectric percolative composites, sulfonated poly(aryl ether ketone) (SPAEK)/a-MWCNTs@PANI, with high dielectric constant and low dielectric loss were fabricated using simple solution blending technique. A SPAEK/a-MWCNTs@PANI composite prepared in this fashion exhibited a high dielectric constant above 800, a dielectric loss tangent less than 1.1 at 10 kHz and room temperature. The morphological study of composites by SEM suggested that the in situ polymerization method of preparing a-MWCNTs@PANI nanofillers was useful to achieve good dispersion of fillers in SPAEK matrix.

Numerical simulation of heat and mass transfer in fluidised bed heat treatment furnaces

In this paper, a novel combined theoretical and computational model is developed to simulate the heat and mass transfer between a fluidised bed and a workpiece surface, and within the workpiece by considering the fluidised bed as a medium consisting of a double-particle layer and an even porous layer. The heat and mass-transfer flux from the fluidised bed to the workpiece surface is contributed by dense and bubble phases, respectively. The convective heat and mass transfer is simulated by analysing the gas dynamics in the fluidised bed, while radiative heat transfer is modelled by simulating photon emission in a three-dimensional particle array. The simulation shows that convection is approximately constant, while radiation contributes significantly to the heat transfer. The heat-transfer coefficient on an immersed surface near particles is about 6–10 times that on other areas. The transient heat and mass-transfer coefficient, heat and mass-transfer flux on any surface of the workpiece, transient temperature and carbon distributions at any position of the workpiece during the metal carburising process are studied with the simulation.

Influence of low-strain deformation characteristics of high strength sheet steel on curl and springback in bend-under-tension tests

The influence of low-strain deformation behavior on curl and springback in advanced high strength steels (AHSS) was assessed using a bend-under-tension test. The effect of yielding behavior on curl and springback was examined by heat-treating two dual-phase steels to induce yield point elongation, while keeping a relatively constant tensile strength and a constant sheet thickness. A dual-phase and TRIP steel with similar initial thickness and tensile strengths were also examined to investigate the effect of work-hardening on curl and springback. It is shown that while current understanding limits prediction of curl and springback in bending under tension using only the initial sheet thickness and tensile strength, both the yielding and work-hardening behavior can affect the results. Explanations for these effects are proposed in terms of the discontinuous yielding and flow stress in the materials.

Numerical investigation of ramp and constant pressurization system during tube crushing process

The requirement for the automotive industry at present and even more so in the future is to simultaneously develop materials, economic forming processes and techniques for weight reduction of the component. To fulfil this need steel manufacturers have developed Advanced High Strength Steels which have high strength and good formability. Due to high strength, material thickness can be reduced without compromising the function of the component. High pressure hydro forming is one process that can be used to produce complex components from these materials. However, reduction in material thickness of these steels does not result in a large decrease of internal fluid pressure and die closing force during tube hydro forming and hence the higher strengths of these steels will require higher pressures. Tube crushing is a process in which the component can be formed with low pressures. In this paper numerical comparison of ramp and constant pressurization system during tube crushing for a TRIP steel is studied. It is proposed that ramp pressure is the best option to obtain a part with accurate geometrical shape from tube crushing with less die closing force. The stress and thickness distribution of the part during tube crushing were critically analysed.

Australia's strengths and weaknesses in technology transfer and R&D exploitation : GEM survey "experts" views compared with public policy and other published data

There has been increasing public debate in Australia in recent years about research culture in universities and other publicly funded research agencies such as CSIRO and its impact on Australia's performance in generating economic, social and environmental benefits to the Australian community from the large amount of public funding for R&D. This is the supply side issue. On the demand side there is equally concern about the technology absorptive capacity of Australian. business as illustrated by the low proportion of gross business research expenditure (GERD) spent by business (BERD). Against this background, this paper has explored the views of abut 100 "experts" interviewed in the Australian Global Entrepreneurship Monitor (GEM) studies in the years 2000, 2001, 2002 and 2003 on the issues, strengths and weaknesses of Australia's technology transfer performance as it applies to new technology small firms. The paper has also explored evidence for any longitudinal change over this period.

Levy grant training scheme evolution : focus on Fiji and Singapore

This thesis examines the evolution of national training policy in Fiji since 1973 with a particular emphasis on the national levy-grant scheme that was introduced in Fiji in that same year. Developments in the Fiji National Training Council (FNTC) levy-grants scheme since its inception, including substantive amendments to the legislation in late 2002, form part of the scholarship. The thesis will provide an analytical narration of the training policy objectives and their transformation over a time span of almost three decades in the context of a small island nation. To inform this study, it was considered essential to compare the Fiji experience of levy grants schemes with other levy grants scheme. The author decided to use as the focal comparative benchmark the case of the Skills Development Fund (SDF) in Singapore. The SDF has been increasingly portrayed, by the World Bank, the International Labour Organisation and other influential agencies, as the best practice case when it comes to managing a training levy grants scheme. The thesis adopted a qualitative approach that utilized elements of case study, historical research, and key person interviews. The challenges of doing 'insider* research were explored because of its pertinence to the study. Because the study also involved the comparison of the policy experiences of two distinct countries, it was imperative to consider the issues and challenges of undertaking comparative research with particular reference to training matters- Given that training is often enmeshed with other human resources management issues, cognisance was taken of some of the broader debates in this regard. Following consideration of the methodological issues, the research paper explores the objectives of national training strategies and, in particular, issues relating to national competitiveness and skills development. The purpose is to situate the issue of training and skills development within the broader discourse of national development. Alternative approaches to the strategic role of training are considered both at the national and organisational level and some of the classic and current debates surrounding human capital investment are visited. The thesis then proceeds to examine the forms of, and rationale for government interventions in the area of training. One of the challenges both in practice and theoretically is to arrive at a consensual definition of training because of the constantly evolving context and boundaries in which training policies are fashioned. This provides the setting to examine the role that governments can and do play in skills development and how levy-grant schemes, in particular, contribute to the process. Three forms of levy grants schemes are identified and examined: levy-generating; levy-exemption; and levy-grant and reimbursement schemes. The levy-grant and reimbursement variant is the basic thrust of this thesis. In this regard, the UK experience with the levy-grant system from 1964 to 1981 is also reviewed. Some of the issues in relation to training levies are scrutinized including the levy as a sheltered source of training finance, levy rates, duration of levy, impact of levy on the quality and quantity of training, benefits to small businesses, links between training and strategic business objectives, repackaging of training to qualify for grants, and the process by which training levy policies are devised. In looking at the policy formulation, it was necessary to unpack the processes involved and explore the role of the state further. In relation to policy development and implementation, the consultation processes, role of bureaucrats, the policy context, and approaches to policy transfer are examined. In looking at the role of the state in policy development, the alternative roles of government are explored and the concepts of the 'developmental state' and the 'corporatist state* evaluated. The notion of the developmental state has particular relevance to this study given the emphasis placed by the Singaporean government on human resource development policies. This sets the scene for a detailed examination of the role of levy-grant training schemes in Fiji and Singapore. The Skills Development Fund in Singapore was developed as an integral component of national economic policy when the Singaporean government decided to break out of the 'low-skills' trap and move the economy towards a higher value adding structure. The levy-grant system was designed to complement the strategy by focusing on upgrading the skills of employees on lower incomes, the assumption being that employees on lower remuneration were more likely to need skills upgrading. The study notes that the early objectives of the SDF were displaced when it was revealed that the bulk of SDF expenditure was directed at higher level supervisory and management training. As a result, the SDF had to refocus its activities on small and medium enterprises and the workers who were likely to miss out on formal training opportunities. The Singaporean context also shows trade unions playing a significant role in worker education and literacy programmes financed under the SDF. To understand this requires some understanding of the historical linkages between the present Singaporean government and trade union leadership. Another aspect of the development of the SDF has been the constant shifting of the institutional responsibility for the scheme. As late as September 2003, the SDF was again moved, this time to the newly created Singapore Workforce Development Agency, with the focus turning to lifelong learning and assisting Singaporeans who are unemployed or made redundant as a result of the economic restructuring. The Fiji experience with the FNTC scheme is different. It evolved in the context of perceived skills shortages but there was a degree of ambiguity over its objectives. There were no specific linkages with economic policy. Relationships with other public training institutions and more recently, private training providers, have been fraught with difficulties. The study examines the origins of the policy, the early difficulties including perceived employer grievances, and the numerous external assessments of the Fiji levy-grant scheme noting that some of them were highly critical. The thesis also examines an attempted reform of the scheme in 1992-93 that proved unsuccessful and the more recent legislative reforms to the scheme in 2002 that have expanded the role of the scheme to encompass, inter alia, national occupational standards and accreditation activities. The thesis concludes by comparing the two schemes noting that the SDF is well entrenched as a policy instrument in Singapore whilst the FNTC is facing a struggle to assert its legitimacy in Fiji.

Similar metabolic adaptations during exercise after low volume sprint interval and traditional endurance training in humans

Low-volume ‘sprint’ interval training (SIT) stimulates rapid improvements in muscle oxidative capacity that are comparable to levels reached following traditional endurance training (ET) but no study has examined metabolic adaptations during exercise after these different training strategies. We hypothesized that SIT and ET would induce similar adaptations in markers of skeletal muscle carbohydrate (CHO) and lipid metabolism and metabolic control during exercise despite large differences in training volume and time commitment. Active but untrained subjects (23 ± 1 years) performed a constant-load cycling challenge (1 h at 65% of peak oxygen uptake before and after 6 weeks of either SIT or ET (n = 5 men and 5 women per group). SIT consisted of four to six repeats of a 30 s ‘all out’ Wingate Test (mean power output ∼500 W) with 4.5 min recovery between repeats, 3 days per week. ET consisted of 40–60 min of continuous cycling at a workload that elicited ∼65% (mean power output ∼150 W) per day, 5 days per week. Weekly time commitment (∼1.5 versus ∼4.5 h) and total training volume (∼225 versus ∼2250 kJ week−1) were substantially lower in SIT versus ET. Despite these differences, both protocols induced similar increases (P < 0.05) in mitochondrial markers for skeletal muscle CHO (pyruvate dehydrogenase E1α protein content) and lipid oxidation (3-hydroxyacyl CoA dehydrogenase maximal activity) and protein content of peroxisome proliferator-activated receptor-γ coactivator-1α. Glycogen and phosphocreatine utilization during exercise were reduced after training, and calculated rates of whole-body CHO and lipid oxidation were decreased and increased, respectively, with no differences between groups (all main effects, P < 0.05). Given the markedly lower training volume in the SIT group, these data suggest that high-intensity interval training is a time-efficient strategy to increase skeletal muscle oxidative capacity and induce specific metabolic adaptations during exercise that are comparable to traditional ET.

Dual responsive chemosensors for anions : the combination of fluorescent PET (Photoinduced Electron Transfer) and colorimetric chemosensors in a single molecule

The design and synthesis of two novel fluorescent PET anion sensors is described, based on the principle of ‘fluorophore-spacer-(anion)receptor’. The sensors 1 and 2 employ simple diaromatic thioureas as anion receptors, and the fluorophore is a naphthalimide moiety that absorbs in the visible part of the spectrum and emits in the green. Upon recognition of anions such as F⁻ and AcO⁻ in DMSO, the fluorescence emission of 1 and 2 was ‘switched off’, with no significant changes in the UV–vis spectra. This recognition shows a 1:1 binding between the receptor and the anions. In the case of F⁻, further additions of the anion, gave rise to large changes in the UV–vis spectra, where the λ_max at 455 nm was shifted to 550 nm. These changes are thought to be due to the deprotonation of the 4-amino moiety of the naphthalimide fluorophore. This was in fact found to be the case, using simple naphthalimide derivatives such as 6. Sensors 1 and 2 can thus display dual sensing action; where at low concentrations, the fluorescence emission is quenched, and at higher concentrations the absorption spectra are modulated.

Suppression of natural convection heat transfer coefficients in an attic shaped enclosure

The use of convection suppression devices has been widely discussed in the literature as a means of reducing natural convection heat loss from enclosed spaces. In this study the use of a single baffle was examined as a possible low cost means of suppressing heat loss by natural convection in an attic shaped enclosure.

Recently the authors experimentally demonstrated that the natural convection heat transfer for an attic shaped enclosure with Grashof Numbers in the range of 107 to 109 [1] could be predicted using a correlation in the literature developed for Grashof Numbers in the range 105 and 106 [2]. However, in this study the impact of adding a single baffle to the enclosure was examined. It was found that the heat transfer coefficient changes with increasing baffle length, and can be predicted using a modified form of the correlation presented in [1], as shown in Eq. (1).

Low complexity MMSE based channel estimation technique for LTE OFDMA systems

Long term evolution (LTE) is designed for high speed data rate, higher spectral efficiency, and lower latency as well as high-capacity voice support. LTE uses single carrierfrequency division multiple access (SC-FDMA) scheme for the uplink transmission and orthogonal frequency division multiple access (OFDMA) in downlink. The one of the most important challenges for a terminal implementation are channel estimation (CE) and equalization. In this paper, a minimum mean square error (MMSE) based channel estimator is proposed for an OFDMA systems that can avoid the ill-conditioned least square (LS) problem with lower computational complexity. This channel estimation technique uses knowledge of channel properties to estimate the unknown channel transfer function at non-pilot subcarriers.