A ducted wind turbine simulation model for building simulation

Power production is shifting away from centralized generation plants to production of heat and power at the point of demand. A technology that may play a part in this shift is the ducted wind turbine (DWT). The emergence of small building integrated micro turbines opens up the possibility of utilizing the differential pressures occurring around buildings for local power production. This paper describes work to develop and test a simple mathematical model of a ducted wind turbine and its integration within a building simulation tool. A case study in which the simulation model will be used to analyse of the likely power output from a building incorporating ducted wind turbines within the façade is also presented

Flight data analysis of power subsystem degradation at near synchronous altitude Quarterly report

Flight data analysis of spacecraft power subsystem degradation at near synchronous altitud

X-ray photoelectron spectroscopy investigation of the mixed anion GaSb/InAs heterointerface

X-ray photoelectron spectroscopy has been used to measure levels of anion cross-incorporation and to study interface formation for the mixed anion GaSb/lnAs heterojunction. Anion cross-incorporation was measured in 20 Å thick GaSb layers grown on lnAs, and 20 Å thick InAs layers grown on GaSb for cracked and uncracked sources. It was found that significantly less anion cross-incorporation occurs in structures grown with cracked sources. Interface formation was investigated by studying Sb soaks of InAs surfaces and As soaks of GaSb surfaces as a function of cracker power and soak time. Exchange of the group V surface atoms was found to be an increasing function of both cracker power and soak time. We find that further optimization of current growth parameters may be possible by modifying the soak time used at interfaces

Multimodal mapping: Using mind maps to negotiate emerging professional communication practices and identity in higher education

Mind or concept maps have long been viewed as helpful tools to plan texts. The pedagogical focus is often focused on the end product as material artefact, with less pedagogical or assessment attention being paid to the process of mind mapping. A process-product approach to text and text-in-use can fulfil a variety of pedagogical goals that allow participants in a professional communication course to collaboratively negotiate meaning-making. By presenting mind maps in class and receiving immediate peer feedback, students have the opportunity to redesign their work to enhance understanding. This article uses a multimodal social semiotic approach as well as the notion of authorial stance (defined multimodally) to analyse a mind map, as both artefact and presentation. The analysis shows how a particular student transforms her work and thinking during in-class engagement. Besides turn-taking and experiential participation as communicator and audience, this negotiation of meaning-making contributes to graduate work-readiness. We argue that these scaffolding and scaffolded activities act to engage student identity formation as emerging professionals for the workplace. 

A social learning theory model for understanding team-based professional communication learning for computer science students

The study interrogates an annual course with undergraduate computer science students that takes place against the background of national student protests at universities across South Africa to effect equitable access to universities. It uses reflections by computer science students of their experience of collaborative work on a Scenario Pedagogy (SP) course, as well as the results of a survey of student collaborative practices in a digital space as a window into their learning trajectories. The study demonstrates and offers an understanding of how SP can contribute to developing computer science students as communicators in their discipline at university and future workplaces. It explores the usefulness of Communities of Practice (COP) and Knowledgeability across Landscapes of Practice (KLP) theory as an analytical tool-set as well as a descriptive language for investigating and explaining learning events. The changing and changed landscape of higher education and the world of work present new challenges and opportunities, particularly in curriculum development and delivery. Utilising “authentic” pedagogies and social learning theory provides appropriate tools for meeting these challenges. Exploring reflective practices and their contribution to the emerging of transformed practices and identities in the South African higher education sector would be a fruitful avenue of future research

Reinforcer magnitude and demand under fixed-ratio schedules with domestic hens

This study compared three methods of normalizing demand functions to allow comparison of demand for different commodities and examined how varying reinforcer magnitudes affected these analyses. Hens responded under fixed-ratio schedules in 40-min sessions with response requirement doubling each session and with 2-s, 8-s, and 12-s access to wheat. Over the smaller fixed ratios overall response rates generally increased and were higher the shorter the magazine duration. The logarithms of the number of reinforcers obtained (consumption) and the fixed ratio (price) were well fitted by curvilinear demand functions (Hursh et al., 1988. Journal of the Experimental Analysis of Behavior 50, 419–440) that were inelastic (b negative) over small fixed-ratios. The fixed ratio with maximal response rate (Pmax) increased, and the rate of change of elasticity (a) and initial consumption (L) decreased with increased magazine duration. Normalizing consumption using measures of preference for various magazine durations (3-s vs. 3-s, 2-s vs. 8-s, and 2-s vs. 12-s), obtained using concurrent schedules, gave useful results as it removed the differences in L. Normalizing consumption and price (Hursh and Winger, 1995. Journal of the Experimental Analysis of Behavior 64, 373–384) unified the data functions as intended by that analysis. The exponential function (Hursh and Silberberg, 2008. Psychological Review, 115, 186–198) gave an essential value that increased (i.e., α decreased significantly) as magazine duration decreased. This was not as predicted, since α should be constant over variations in magazine duration, but is similar to previous findings using a similar procedure with different food qualities (hens) and food quantities (rats)