Low-temperature synthesis and sintering of γ-Y2Si2O7

In this article, a novel pressureless solid-liquid reaction method is presented for preparation of yttrium disilicate (γ-Y2Si2O7). Single-phase γ-Y2Si2O7 powder was synthesized by calcination of SiO2 and Y2O3 powders with the addition of LiYO2 at 1400 °C for 4 h. The addition of LiYO2 significantly decreased the synthesis temperature, shortened the calcination time, and enhanced the stability of γ-Y2Si2O7. The sintering of these powders in air and O2 was studied by means of thermal mechanical analyzer. It is shown that the γ-Y2Si2O7 sintered in oxygen had a faster densification rate and a higher density than that sintered in air. Furthermore, single-phase γ-Y2Si2O7 with a density of 4.0 g/cm3 (99% of the theoretical density) was obtained by pressureless sintering at 1400 °C for 2 h in oxygen. Microstructures of the sintered samples are studied by scanning electron microscope.

A journey access tool to facilitate mobility-related access for people with disabilities in low and middle income countries

People with disabilities (PWD) experience difficulties in accessing the transport system (including both infrastructure and services) to meet their needs for health care, employment and other activities. Our research shows that lack of access to the journeys needed for these purposes is a more significant barrier in low and middle income countries than in high income countries, and results in inadequate health care, rehabilitation and access to education and employment. At the same time, the existing transport system in low and middle income countries presents much higher road crash risks than in high income countries. By combining the principles and methods of Road Safety Audit and disability access, and adapting these Western approaches to a low/middle income country context, we have worked with Handicap International Cambodia to develop a Journey Access Tool (JAT) for use by disabled peoples’ organisations (DPOs), people with a disability and other key stakeholders. A key element of the approach is that it involves the participation of PWD on the journeys that they need to take, and it identifies infrastructure and service improvements that should be prioritised in order to facilitate access to these journeys. The JAT has been piloted in Cambodia with a range of PWD. This presentation will outline the design of the JAT and the results of the pilot studies. The information gained thus far strongly suggests that the JAT is a valuable and cost-effective approach that can be used by DPOs and professionals to identify barriers to access and prioritise the steps needed to address them.

Comparison of the sensitivity of different sensor technologies to imbalance severity in low speed wind turbines

Imbalance is not only a direct major cause of downtime in wind turbines, but also accelerates the degradation of neighbouring and downstream components (e.g. main bearing, generator). Along with detection, the imbalance quantification is also essential as some residual imbalance always exist even in a healthy turbine. Three different commonly used sensor technologies (vibration, acoustic emission and electrical measurements) are investigated in this work to verify their sensitivity to different imbalance grades. This study is based on data obtained by experimental tests performed on a small scale wind turbine drive train test-rig for different shaft speeds and imbalance levels. According to the analysis results, electrical measurements seem to be the most suitable for tracking the development of imbalance.

The effect of high versus low intensity heat acclimation on performance and neuromuscular responses

This study examined the effect of exercise intensity and duration during 5-day heat acclimation (HA) on cycling performance and neuromuscular responses. 20 recreationally trained males completed a ‘baseline’ trial followed by 5 consecutive days HA, and a ‘post-acclimation’ trial. Baseline and post-acclimation trials consisted of maximal voluntary contractions (MVC), a single and repeated countermovement jump protocol, 20 km cycling time trial(TT) and 5x6 s maximal sprints (SPR). Cycling trials were undertaken in 33.0 ± 0.8 °C and 60 ± 3% relative humidity.Core(Tcore), and skin temperatures (Tskin), heart rate (HR), rating of perceived exertion (RPE) and thermal sensation were recorded throughout cycling trials. Participants were assigned to either 30 min high-intensity (30HI) or 90 min low-intensity (90LI) cohorts for HA, conducted in environmental conditions of 32.0 ± 1.6 °C. Percentage change time to complete the 20 km TT for the 90LI cohort was significantly improved post-acclimation(-5.9 ± 7.0%; P=0.04) compared to the 30HI cohort (-0.18 ± 3.9%; P<0.05). The 30HI cohort showed greatest improvements in power output (PO) during post-acclimation SPR1 and 2 compared to 90LI (546 ± 128 W and 517 ± 87 W,respectively; P<0.02). No differences were evident for MVC within 30HI cohort, however, a reduced performance indicated by % change within the 90LI (P=0.04). Compared to baseline, mean Tcore was reduced post-acclimation within the 30HI cohort (P=0.05) while mean Tcore and HR were significantly reduced within the 90LI cohort (P=0.01 and 0.04, respectively). Greater physiological adaptations and performance improvements were noted within the 90LI cohort compared to the 30HI. However, 30HI did provide some benefit to anaerobic performance including sprint PO and MVC. These findings suggest specifying training duration and intensity during heat acclimation may be useful for specific post-acclimation performance.

Low-impact Use: A New Standard

Once the ugly duckling of the lighting world, the fluorescent bulb recently has become something of an eco-darling thanks to its energy efficiency. Whereas a standard off-the-shelf incandescent bulb devotes only about five percent of its total electrical consumption to produce visible light (the remainder is released in heat), fluorescent lighting employs an entirely different process (it radiates rather than burns) that is four to six times more efficient. Fluorescents are indisputably superior in ­performance, but up to 5 milligrams of mercury, a hazardous trace metal, is included in the manufacture of each lamp