Determination of mean atmospheric densities from the explorer ix satellite

Mean atmospheric densities from changes in orbital elements of Explorer IX satellit

The Suppression and Extinction of Class A Fires Using Water Sprays

Water has long been the agent of choice for fighting Class' A' fires In fact the thermal characteristics of water make it ideally suitable as an extinguishing agent for most types of fire, whether it is used to extract heat directly from the flames, the hot products of combustion or from the surface of the fuel The phase change from liquid water to water vapour (steam) is particularly effective in extracting thermal energy and the production of large quantities of water vapour may further contribute to fire extinguishment by inerting the surrounding atmosphere, especially where the fire is confined to some extent The literature review which forms the basis of this report has been conducted in order to establish the current state-of-the-art regarding the use of water sprays for the suppression and extinction of Class' A' fires It is concluded that the current state-of-the-art is close to the point where a description of fire extinction can be given from the initiation of suppression to the point of final extinguishment. this is a stated FRDG objective However. certain gaps in the knowledge base still exist and these are highlighted. provisional recommendations are made for the direction of future research in these areas

A New Circularly Polarized Rectenna for Wireless Power Transmission and Data Communication

Small distributed wireless sensors are becoming very important in many aspects of our lives. While low data rate passive sensors operate with little energy there is a need for moderate to high data rate distributed sensors for infrastructure monitoring and other applications. Such sensors will require their batteries or onboard capacitors to be charged when depleted for proper operation. In this letter, we propose a circularly polarized (CP) microstrip patch antenna that can function as a WLAN antenna in the 5.15-5.35 GHz and as a rectenna at 5.5 GHz

Can Handheld Thermal Imaging Technology Improve Detection of Poachers in African Bushveldt?

Illegal hunting (poaching) is a global threat to wildlife. Anti-poaching initiatives are making increasing use of technology, such as infrared thermography (IRT), to support traditional foot and vehicle patrols. To date, the effectiveness of IRT for poacher location has not been tested under field conditions, where thermal signatures are often complex. Here, we test the hypothesis that IRT will increase the distance over which a poacher hiding in African scrub bushveldt can be detected relative to a conventional flashlight. We also test whether any increase in effectiveness is related to the cost and complexity of the equipment by comparing comparatively expensive (22000 USD) and relatively inexpensive (2000 USD) IRT devices. To test these hypotheses we employ a controlled, fully randomised, double-blind procedure to find a poacher in nocturnal field conditions in African bushveldt. Each of our 27 volunteer observers walked three times along a pathway using one detection technology on each pass in randomised order. They searched a prescribed search area of bushveldt within which the target was hiding. Hiding locations were pre-determined, randomised, and changed with each pass. Distances of first detection and positive detection were noted. All technologies could be used to detect the target. Average first detection distance for flashlight was 37.3m, improving by 19.8m to 57.1m using LIRT and by a further 11.2m to 68.3m using HIRT. Although detection distances were significantly greater for both IRTs compared to flashlight, there was no significant difference between LIRT and HIRT. False detection rates were low and there was no significant association between technology and accuracy of detection. Although IRT technology should ideally be tested in the specific environment intended before significant investment is made, we conclude that IRT technology is promising for anti-poaching patrols and that for this purpose low cost IRT units are as effective as units ten times more expensive

Teaching Complex and Controversial Issues: Importance of In-Situ Experiences in Changing Perceptions of Global Challenges

Engaging people with controversial and emotive issues that are inherently complex is challenging, especially when those issues are multifaceted or multidisciplinary, span environmental, economic, social, and political contexts, are global in scope, or where circumstances and implications differ spatially. Teaching such issues requires teachers and learners to navigate a challenging landscape of nuance and conflicting perspectives; immersive place-based learning might facilitate more meaningful exploration of such issues, but this has not previously been studied. In a multi-institution international study, we surveyed 164 participants (12 groups; 9 institutions) before and after an immersive fieldtrip in South Africa to assess perceptions on contentious issues. Wilcoxon signed-rank tests showed that participants had statistically significant opinion shifts for 17 of 18 statements, including those where change was likely due to improved knowledge or indicative of deeper attitude shifts. Generalised Linear Modelling revealed that propensity for opinion shifts was not influenced by demographics (age, gender), location (country of origin) or trip type (formal or informal). We conclude that in an increasingly complex world, context relevant immersive experiences that facilitate deep learning by providing opportunities to explore contentious issues in situ are an ever-more valuable tool, not just for attainment but also for developing personal perspectives and as a catalyst for societal transitions