976 resultados para Heat engineering
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BACKGROUND There is little doubt that our engineering graduates’ ability to identify cultural differences and their potential to impact on engineering projects, and to work effectively with these differences is of key importance in the modern engineering practice. Within engineering degree programs themselves there is also a significant need to recognise the impact of changing student and staff profiles on what happens in the classroom. The research described in this paper forms part of a larger project exploring issues of intercultural competence in engineering. PURPOSE This paper presents an observational and survey study of undergraduate and postgraduate engineering students from four institutions working in groups on tasks with a purely technical focus, or with a cultural and humanitarian element. The study sought to explore how students rate their own intercultural competence and team process and whether any differences exist depending on the nature of the task they are working on. We also investigated whether any differences were evident between groups of first year, second year and postgraduate students. DESIGN/METHOD The study used the miniCQS instrument (Ang & Van Dyne, 2008) and a Bales Interaction Process Analysis based scale (Bales, 1950; Carney, 1976) to collect students self ratings of group process, task management, and cultural experience and behaviour. The Bales IPA was also used for coding video observations of students working in groups. Survey data were used to form descriptive variables to compare outcomes across the different tasks and contexts. Observations analysed in Nvivo were used to provide commentary and additional detail on the quantitative data. RESULTS The results of the survey indicated consistent mean scores on each survey item for each group of students, despite vastly different tasks, student backgrounds and educational contexts. Some small, statistically significant mean differences existed, offering some basic insights into how task and student group composition could affect self ratings. Overall though, the results suggest minimal shift in how students view group function and their intercultural experience, irrespective of differing educational experience. CONCLUSIONS The survey results, contrasted with group observations, indicate that either students are not translating their experience (in the group tasks) into critical self assessment of their cultural competence and teamwork, or that they become more critical of team performance and cultural competence as their competence in these areas grows, so their ratings remain consistent. Both outcomes indicate that students need more intensive guidance to build their critical self and peer assessment skills in these areas irrespective of their year level of study.
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BACKGROUND The work described in this paper has emerged from an ALTC/OLT funded project, Exploring Intercultural Competency in Engineering. The project indentified many facets of culture and intercultural competence that go beyond a culture-as-nationality paradigm. It was clear from this work that resources were needed to help engineering educators introduce students to the complex issues of culture as they relate to engineering practice. A set of learning modules focussing on intercultural competence in engineering practice were developed early on in the project. Through the OLT project, these modules have been expanded into a range of resources covering various aspects of culture in engineering. Supporting the resources, an eBook detailing the ins and outs of intercultural competency has also been developed to assist engineering educators to embed opportunities for students to develop skills in unpacking and managing cross-cultural challenges in engineering practice. PURPOSE This paper describes the key principles behind the development of the learning modules, the areas they cover and the eBook developed to support the modules. The paper is intended as an introduction to the approaches and resources and extends an invitation to the community to draw from, and contribute to this initial work. DESIGN/METHOD A key aim of this project was to go beyond the culture-as-nationality approach adopted in much of the work around intercultural competency (Deardorff, 2011). The eBook explores different dimensions of culture such as workplace culture, culture’s influence on engineering design, and culture in the classroom. The authors describe how these connect to industry practice and explore what they mean for engineering education. The packaged learning modules described here have been developed as a matrix of approaches moving from familiar known methods through complicated activities relying to some extent on expert knowledge. Some modules draw on the concept of ‘complex un-order’ as described in the ‘Cynefin domains’ proposed by Kurtz and Snowden (2003). RESULTS Several of the modules included in the eBook have already been trialled at a variety of institutions. Feedback from staff has been reassuringly positive so far. Further trials are planned for second semester 2012, and version 1 of the eBook and learning modules, Engineering Across Cultures, is due to be released in late October 2012. CONCLUSIONS The Engineering Across Cultures eBook and learning modules provide a useful and ready to employ resource to help educators tackle the complex issue of intercultural competency in engineering education. The book is by no means exhaustive, and nor are the modules, they instead provide an accessible, engineering specific guide to bringing cultural issues into the engineering classroom.
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BACKGROUND The engineering profession in Australia has failed to attract young women for the last decade or so despite all the effort that have gone into promoting engineering as a preferred career choice for girls. It is a missed opportunity for the profession to flourish as a heterogeneous team. Many traditional initiatives and programs have failed to make much impact or at best incremental improvement into attracting and retaining more women in the profession. The reasons why girls and young women in most parts of the world show little interest in engineering haven't changed, despite all the efforts to address them, the issue proposed here in this paper is with the perceptions of engineering in the community and the confidence to pursue it. This gender imbalance is detrimental for the engineering profession, and hence an action-based intervention strategy was devised by the Women in Engineering Qld Chapter of Engineers Australia in 2012 to change the perceptions of school girls by redesigning the engagement strategy and key messages. As a result, the “Power of Engineering Inc” (PoE) was established as a not-for-profit organisation, and is a collaborative effort between government, schools, universities, and industry. This paper examines a case study in changing the perceptions of year 9 and 10 school girls towards an engineering career. PURPOSE To evaluate and determine the effectiveness of an intervention in changing the perceptions of year 9 and 10 school girls about engineering career options, but specifically, “What were their perceptions of engineering before today and have those perceptions changed?” DESIGN/METHOD The inaugural Power of Engineering (PoE) event was held on International Women’s Day, Thursday 8 March 2012 and was attended by 131 high school female students (year 9 and 10) and their teachers. The key message of the day was “engineering gives you the power to change the world”. A questionnaire was conducted with the participating high school female students, collecting both quantitative and qualitative data. The survey instrument has not been validated. RESULTS The key to the success of the event was as a result of collaboration between all participants involved and the connection created between government, schools, universities and industry. Of the returned surveys (109 of 131), 91% of girls would now consider a career in engineering and 57% who had not considered engineering before the day would now consider a career in engineering. Data collected found significant numbers of negative and varying perceptions about engineering careers prior to the intervention. CONCLUSIONS The evidence in this research suggests that the intervention assisted in changing the perceptions of year 9 and 10 female school students towards engineering as a career option. Whether this intervention translates into actual career selection and study enrolment is to be determined. In saying this, the evidence suggests that there is a critical and urgent need for earlier interventions prior to students selecting their subjects for year 11 and 12. This intervention could also play its part in increasing the overall pool of students engaged in STEM education.
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There is a growing gap between engineering practice and engineering education that may be contributing to less engineers practicing in industry. Coaching approach to learning and teaching has been proven to be an effective way to develop people in the workplace. A pilot coaching program is offered to Engineering and Technology students in Queensland University of Technology to enable holistic growth in order to better integrate them to the work force and society at large. The results and findings of this program will be published once the program has been completed
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Currently, 1.3 billion tonnes of food is lost annually due to lack of proper processing and preservation method. Drying is one of the easiest and oldest methods of food processing which can contribute to reduce that huge losses, combat hunger and promote food security. Drying increase shelf life, reduce weight and volume of food thus minimize packing, storage, and transportation cost and enable storage of food under ambient environment. However, drying is a complex process which involves combination of heat and mass transfer and physical property change and shrinkage of the food material. Modelling of this process is essential to optimize the drying kinetics and improve energy efficiency of the process. Since material properties varies with moisture content, the models should not consider constant materials properties, constant diffusion .The objective of this paper is to develop a multiphysics based mathematical model to simulate coupled heat and mass transfer during convective drying of fruit considering variable material properties. This model can be used predict the temperature and moisture distribution inside the food during drying. Effect of different drying air temperature and drying air velocity on drying kinetics has been demonstrated. The governing equations of heat and mass transfer were solved with Comsol Multiphysics 4.3.
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We examined the variation in association between high temperatures and elderly mortality (age ≥ 75 years) from year to year in 83 US cities between 1987 and 2000. We used a Poisson regression model and decomposed the mortality risk for high temperatures into: a “main effect” due to high temperatures using lagged non-linear function, and an “added effect” due to consecutive high temperature days. We pooled yearly effects across both regional and national levels. The high temperature effects (both main and added effects) on elderly mortality varied greatly from year to year. In every city there was at least one year where higher temperatures were associated with lower mortality. Years with relatively high heat-related mortality were often followed by years with relatively low mortality. These year to year changes have important consequences for heat-warning systems and for predictions of heat-related mortality due to climate change.
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Optimisation of Organic Rankine Cycles (ORCs) for binary-cycle geothermal applications could play a major role in the competitiveness of low to moderate temperature geothermal resources. Part of this optimisation process is matching cycles to a given resource such that power output can be maximised. Two major and largely interrelated components of the cycle are the working fluid and the turbine. Both components need careful consideration. Due to the temperature differences in geothermal resources a one-size-fits-all approach to surface power infrastructure is not appropriate. Furthermore, the traditional use of steam as a working fluid does not seem practical due to the low temperatures of many resources. A variety of organic fluids with low boiling points may be utilised as ORC working fluids in binary power cycle loops. Due to differences in thermodynamic properties, certain fluids are able to extract more heat from a given resource than others over certain temperature and pressure ranges. This enables the tailoring of power cycle infrastructure to best match the geothermal resource through careful selection of the working fluid and turbine design optimisation to yield the optimum overall cycle performance. This paper presents the rationale for the use of radial-inflow turbines for ORC applications and the preliminary design of several radial-inflow turbines based on a selection of promising ORC cycles using five different high-density working fluids: R134a, R143a, R236fa, R245fa and n-Pentane at sub- or trans-critical conditions. Numerous studies published compare a variety of working fluids for various ORC configurations. However, there is little information specifically pertaining to the design and implementation of ORCs using realistic radial turbine designs in terms of pressure ratios, inlet pressure, rotor size and rotational speed. Preliminary 1D analysis leads to the generation of turbine designs for the various cycles with similar efficiencies (77%) but large differences in dimensions (139289 mm rotor diameter). The highest performing cycle (R134a) was found to produce 33% more net power from a 150°C resource flowing at 10 kg/s than the lowest performing cycle (n-Pentane).
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The use of Bayesian methodologies for solving optimal experimental design problems has increased. Many of these methods have been found to be computationally intensive for design problems that require a large number of design points. A simulation-based approach that can be used to solve optimal design problems in which one is interested in finding a large number of (near) optimal design points for a small number of design variables is presented. The approach involves the use of lower dimensional parameterisations that consist of a few design variables, which generate multiple design points. Using this approach, one simply has to search over a few design variables, rather than searching over a large number of optimal design points, thus providing substantial computational savings. The methodologies are demonstrated on four applications, including the selection of sampling times for pharmacokinetic and heat transfer studies, and involve nonlinear models. Several Bayesian design criteria are also compared and contrasted, as well as several different lower dimensional parameterisation schemes for generating the many design points.
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Bomb technicians perform their work while encapsulated in explosive ordnance disposal (EOD) suits. Designed primarily for safety, these suits have an unintended consequence of impairing the body’s natural mechanisms for heat dissipation. Purpose: To quantify the heat strain encountered during an EOD operational scenario in the tropical north of Australia. Methods: All active police male bomb technicians, located in a tropical region of Australia (n=4, experience 7 ± 2.1 yrs, age 34 ± 2 yrs, height 182.3 ± 5.4 cm, body mass 95 ± 4 kg, VO2max 46 ± 5.7 ml.kg-1.min-1) undertook an operational scenario wearing the Med-Eng EOD 9 suit and helmet (~32 kg). The climatic conditions ranged between 27.1–31.8°C ambient temperature, 66-88% relative humidity, and 30.7-34.3°C wet bulb globe temperature. The scenario involved searching a two story non air-conditioned building for a target; carrying and positioning equipment for taking an X-ray; carrying and positioning equipment to disrupt the target; and finally clearing the site. Core temperature and heart rate were continuously monitored, and were used to calculate a physiological strain index (PSI). Urine specific gravity (USG) assessed hydration status and heat associated symptomology were also recorded. Results: The scenario was completed in 121 ± 22 mins (23.4 ± 0.4% work, 76.5 ± 0.4% rest/recovery). Maximum core temperature (38.4 ± 0.2°C), heart rate (173 ± 5.4 bpm, 94 ± 3.3% max), PSI (7.1 ± 0.4) and USG (1.031 ± 0.002) were all elevated after the simulated operation. Heat associated symptomology highlighted that moderate-severe levels of fatigue and thirst were universally experienced, muscle weakness and heat sensations experienced by 75%, and one bomb technician reported confusion and light-headedness. Conclusion: All bomb technicians demonstrated moderate-high levels of heat strain, evidenced by elevated heart rate, core body temperature and PSI. Severe levels of dehydration and noteworthy heat-related symptoms further highlight the risks to health and safety faced by bomb technicians operating in tropical locations.
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This is the project report of a leadership project undertaken jointly by the Queensland University of Technology, University of Technology Sydney, and Monash University. Specific project objectives were to: -To build leadership capacity in teaching and learning, and to improve teaching quality in ICT and Engineering disciplines at three leading Australian universities, and -To facilitate the transference of research leadership to T&L leadership, and disseminate this transference model developed through the project within the Engineering and ICT domains to other disciplines and universities.
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The state of the practice in safety has advanced rapidly in recent years with the emergence of new tools and processes for improving selection of the most cost-effective safety countermeasures. However, many challenges prevent fair and objective comparisons of countermeasures applied across safety disciplines (e.g. engineering, emergency services, and behavioral measures). These countermeasures operate at different spatial scales, are funded often by different financial sources and agencies, and have associated costs and benefits that are difficult to estimate. This research proposes a methodology by which both behavioral and engineering safety investments are considered and compared in a specific local context. The methodology involves a multi-stage process that enables the analyst to select countermeasures that yield high benefits to costs, are targeted for a particular project, and that may involve costs and benefits that accrue over varying spatial and temporal scales. The methodology is illustrated using a case study from the Geary Boulevard Corridor in San Francisco, California. The case study illustrates that: 1) The methodology enables the identification and assessment of a wide range of safety investment types at the project level; 2) The nature of crash histories lend themselves to the selection of both behavioral and engineering investments, requiring cooperation across agencies; and 3) The results of the cost-benefit analysis are highly sensitive to cost and benefit assumptions, and thus listing and justification of all assumptions is required. It is recommended that a sensitivity analyses be conducted when there is large uncertainty surrounding cost and benefit assumptions.
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An investigation of the effect of nano particles on natural convection of water based nanofluids contained in an open rectangular cavity is carried out numerically. The flow pattern and heat transfer characteristics are studied for different values of volume fraction in the range 0 0.2 , Rayleigh number in the range 9 1 Ra 10 and the nano particles with different thermo physical properties. It was found that for low Rayleigh numbers, heat transfer exhibits a decreasing trend for increasing values of volume fraction of oxide nanofluids, whereas for higher values of Rayleigh numbers, an increasing trend of heat transfer was observed due to increase in the volume fraction of nanofluids.
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In this study, natural convection heat transfer and buoyancy driven flows have been investigated in a right angled triangular enclosure. The heater located on the bottom wall while the inclined wall is colder and the remaining walls are maintained as adiabatic. Governing equations of natural convection are solved through the finite volume approach, in which buoyancy is modeled via the Boussinesq approximation. Effects of different parameters such as Rayleigh number, aspect ratio, prantdl number and heater location are considered. Results show that heat transfer increases when the heater is moved toward the right corner of the enclosure. It is also revealed that increasing the Rayleigh number, increases the strength of free convection regime and consequently increases the value of heat transfer rate. Moreover, larger aspect ratio enclosure has larger Nusselt number value. In order to have better insight, streamline and isotherms are shown.
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Numerical study is carried out using large eddy simulation to study the heat and toxic gases released from fires in real road tunnels. Due to disasters about tunnel fires in previous decade, it attracts increasing attention of researchers to create safe and reliable ventilation designs. In this research, a real tunnel with 10 MW fire (which approximately equals to the heat output speed of a burning bus) at the middle of tunnel is simulated using FDS (Fire Dynamic Simulator) for different ventilation velocities. Carbone monoxide concentration and temperature vertical profiles are shown for various locations to explore the flow field. It is found that, with the increase of the longitudinal ventilation velocity, the vertical profile gradients of CO concentration and smoke temperature were shown to be both reduced. However, a relatively large longitudinal ventilation velocity leads to a high similarity between the vertical profile of CO volume concentration and that of temperature rise.
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Numerical investigation on mixed convection of a two-dimensional incompressible laminar flow over a horizontal flat plate with streamwise sinusoidal distribution of surface temperature has been performed for different values of Rayleigh number, Reynolds number and frequency of periodic temperature for constant Prandtl number and amplitude of periodic temperature. Finite element method adapted to rectangular non-uniform mesh elements by a non-linear parametric solution algorithm basis numerical scheme has been employed. The investigating parameters are the Rayleigh number, the Reynolds number and frequency of periodic temperature. The effect of variation of individual investigating parameters on mixed convection flow characteristics has been studied to observe the hydrodynamic and thermal behavior for while keeping the other parameters constant. The fluid considered in this study is air with Prandtl number 0.72. The results are obtained for the Rayleigh number range of 102 to 104, Reynolds number ranging from 1 to 100 and the frequency of periodic temperature from 1 to 5. Isotherms, streamlines, average and local Nusselt numbers are presented to show the effect of the different values of aforementioned investigating parameters on fluid flow and heat transfer.