9 resultados para Fresnel cogenerazione CPV celle multigiunzione

em Queensland University of Technology - ePrints Archive


Relevância:

10.00% 10.00%

Publicador:

Resumo:

Purpose –The introduction of Building Information Model tools over the last 20 years is resulting in radical changes in the Architectural, Engineering and Construction industry. One of these changes concerns the use of Virtual Prototyping - an advanced technology integrating BIM with realistic graphical simulations. Construction Virtual Prototyping (CVP) has now been developed and implemented on ten real construction projects in Hong Kong in the past three years. This paper reports on a survey aimed at establishing the effects of adopting this new technology and obtaining recommendations for future development. Design/methodology/approach – A questionnaire survey was conducted in 2007 of 28 key participants involved in four major Hong Kong construction projects – these projects being chosen because the CVP approach was used in more than one stage in each project. In addition, several interviews were conducted with the project manager, planning manager and project engineer of an individual project. Findings –All the respondents and interviewees gave a positive response to the CVP approach, with the most useful software functions considered to be those relating to visualisation and communication. The CVP approach was thought to improve the collaboration efficiency of the main contractor and sub-contractors by approximately 30 percent, and with a concomitant 30 to 50 percent reduction in meeting time. The most important benefits of CPV in the construction planning stage are the improved accuracy of process planning and shorter planning times, while improved fieldwork instruction and reducing rework occur in the construction implementation stage. Although project teams are hesitant to attribute the use of CVP directly to any specific time savings, it was also acknowledged that the workload of project planners is decreased. Suggestions for further development of the approach include incorporation of automatic scheduling and advanced assembly study. Originality/value –Whilst the research, development and implementation of CVP is relatively new in the construction industry, it is clear from the applications and feedback to date that the approach provides considerable added value to the organisation and management of construction projects.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Les activités et industries culturelles sont aujourd’hui englobées dans une nouvelle approche, celle d’industries créatives. Dans ce contexte, les interrogations sur les contributions de la culture au développement économique peuvent être repensées de manière élargie. La contribution examine les différentes réponses possibles à cette question, et quatre modèles sont ainsi distingués: l’approche du bien être; l’approche concurrentielle; l’approche de la croissance; l’approche de l’innovation. A chacun de ces modèles correspond une interprétation du lien entre activités créatives et économie. Ce sont ces interprétations dont la pertinence est appréciée à l’aide de données statistiques simples.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Building on the recommendations of the Bradley Review (2008), the Australian Federal government intends to promote a higher level of penetration of tertiary qualification across the broader Australian community which is anticipated to result in increased levels of standardisation across university degrees. In the field of property, tertiary academic programs are very closely aligned to the needs of a range of built environment professions and there are well developed synergies between the relevant professional bodies and the educational institutions. The strong nexus between the academic and the professional content is characterised by ongoing industry accreditation which nominates a range of outcomes which the academic programs must maintain across a range of specified metrics. Commonly, the accrediting bodies focus on standard of minimum requirements especially in the area of specialised subject areas where they require property graduates to demonstrate appropriate learning and attitudes. In addition to nominated content fields, in every undergraduate degree program there are also many other subjects which provide a richer experience for the students beyond the merely professional. This study focuses on the nonspecialised knowledge field which varies across the universities offering property degree courses as every university has the freedom to pursue its own policy for these non-specialised units. With universities being sensitive to their role of in the appropriate socialisation of new entrants, first year units have been used as a vehicle to support students’ transition into university education and the final year units seek to support students’ integration into the professional world. Consequentially, many property programs have to squeeze their property-specific units to accommodate more generic units for both first year and final year units and the resulting diversity is a feature of the current range of property degrees across Australia which this research will investigate. The matrix of knowledge fields nominated by the Australian Property Institute for accreditation of degrees accepted for Certified Practising Valuer (CPV) educational requirement and the complementary requirements of the other major accrediting body (RICS) are used to classify and compare similarities and differences across property degrees in the light of the streamlining anticipated from the Bradley Review.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Solar ultraviolet (UV) radiation causes a range of skin disorders as well as affecting vision and the immune system. It also inhibits development of plants and animals. UV radiation monitoring is used routinely in some locations in order to alert the population to harmful solar radiation levels. There is ongoing research to develop UV-selective-sensors [1–3]. A personal, inexpensive and simple UV-selective-sensor would be desirable to measure UV intensity exposure. A prototype of such a detector has been developed and evaluated in our laboratory. It comprises a sealed two-electrode photoelectrochemical cell (PEC) based on nanocrystalline TiO2. This abundant semiconducting oxide, which is innocuous and very sta-ble, is the subject of intense study at present due to its application in dye sensitized solar cells (DSSC) [4]. Since TiO2 has a wide band gap (EG = 3.0 eV for rutile and EG = 3.2 eV for anatase), it is inher-ently UV-selective, so that UV filters are not required. This further reduces the cost of the proposed photodetector in comparison with conventional silicon detectors. The PEC is a semiconductor–electrolyte device that generates a photovoltage when it is illuminated and a corresponding photocur-rent if the external circuit is closed. The device does not require external bias, and the short circuit current is generally a linear function of illumination intensity. This greatly simplifies the elec-trical circuit needed when using the PEC as a photodetector. DSSC technology, which is based on a PEC containing nanocrystalline TiO2 sensitized with a ruthenium dye, holds out the promise of solar cells that are significantly cheaper than traditional silicon solar cells. The UV-sensor proposed in this paper relies on the cre-ation of electron–hole pairs in the TiO2 by UV radiation, so that it would be even cheaper than a DSSC since no sensitizer dye is needed. Although TiO2 has been reported as a suitable material for UV sensing [3], to the best of our knowledge, the PEC configuration described in the present paper is a new approach. In the present study, a novel double-layer TiO2 structure has been investigated. Fabrication is based on a simple and inexpensive technique for nanostructured TiO2 deposition using microwave-activated chemical bath deposition (MW-CBD) that has been reported recently [5]. The highly transparent TiO2 (anatase) films obtained are densely packed, and they adhere very well to the transparent oxide (TCO) substrate [6]. These compact layers have been studied as contacting layers in double-layer TiO2 structures for DSSC since improvement of electron extraction at the TiO2–TCO interface is expected [7]. Here we compare devices incorporating a single mesoporous nanocrystalline TiO2 structure with devices based on a double structure in which a MW-CBD film is situated between the TCO and the mesoporous nanocrystalline TiO2 layer. Besides improving electron extraction, this film could also help to block recombination of electrons transferred to the TCO with oxidized species in the electrolyte, as has been reported in the case of DSSC for compact TiO2 films obtained by other deposition tech-niques [8,9]. The two types of UV-selective sensors were characterized in detail. The current voltage characteristics, spectral response, inten-sity dependence of short circuit current and response times were measured and analyzed in order to evaluate the potential of sealed mesoporous TiO2-based photoelectrochemical cells (PEC) as low cost personal UV-photodetectors.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Cette présentation met en avant la Théorie des Littératies Multiples (TLM) et l’importance de lire, lire le monde et se lire, dans le but de se transformer en contexte plurilingue. La première partie de cette communication sera consacrée à la présentation des principes fondamentaux de la TLM. Il est vrai que la littératie valorisée par l’école est souvent celle qui est la plus prisée dans la recherche et l’enseignement. La TLM enlève la littératie scolaire de sa place privilégiée et l’insère dans un agencement de littératies au foyer, à l’école et dans la communauté. Les littératies, en tant que construit renvoient aux mots, aux gestes, aux attitudes, ou plus exactement, aux façons de parler, de lire, d’écrire et de valoriser les réalités de la vie. Elles sont une façon de devenir avec le monde. Les littératies constituent des textes au sens large (comme par exemple, la musique, l’art, la physique et les athématiques) qui peuvent être visuels,oraux, écrits, tactiles,olfactifs ou numériques. Elles se fusionnent aux contextes sociopolitiques, culturels, économiques, genrés et racialisés, qui de par leur caractère mobile et fluide transforment les littératies génératrices de locuteurs, de scripteurs, d’artistes, d’ava tars et de communautés. Les littératies prennent leur sens en contexte, dans le temps et l’espace où on se trouve De ce fait, leur actualisation n’est pas prédéterminée et est imprévisible. La TLM s’intéresse aux rôles joués par les littératies. Lire, lire le monde et se lire a pour fonction importante entre autres de transformer une vie, une communauté et une société. La deuxième partie de cette communication sera consacrée à un projet de recherche ayant pour objectif d’explorer la façon dont des enfants acquièrent simultanément deux ou plusieurs systèmes d’écriture. Des enfants âgés de 5 à 8 ans ont participé à des activités filmées en salle de classe, au foyer et dans leur quartier. Puis des entretiens ont été menés avec les enfants, leurs parents et leurs enseignants. Ce projet nous permet de mieux saisir ce que signifient en contexte plurilingue les littératies en tant que processus. Le projet s’intéresse à ce qu’implique lire, lire le monde et se lire à l’école, au foyer et dans la communauté. Dans une société pluraliste, nous sommes plus que jamais ensibilisés aux contextes particuliers dans lesquels lire, lire le monde et se lire s’actualisent, qu’il s’agisse d’un nouvel arrivant ou d’une personne vivant en milieu minoritaire.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Il s’agit de faire des étudiants étrangers des usagers de bibliothèques et des apprenants heureux. Les professionnels des bibliothèques peuvent y contribuer, pour peu qu’ils soient sensibles à leurs points forts et aux difficultés qu’ils rencontrent. Cet article part du point de vue des étudiants étrangers recueillis lors d’une enquête qualitative menée dans deux universités australiennes. Celle-ci a révélé que, pris collectivement,ces étudiants sont satisfaits de leur bibliothèque universitaire. D’un point de vue individuel cependant, des difficultés apparaissent, liées à l’organisation de la bibliothèque, de ses services et de ses ressources. Pour certains étudiants, le rôle du personnel est assez flou ; ils ne se doutent même pas que les bibliothécaires peuvent les assister dans leurs études. Pour finir, les formations à la maîtrise de l’information ont été jugées inadaptées à leurs besoins. Cet article se concentre sur trois points à l’attention des bibliothécaires universitaires australiens : être sensible aux expériences des étudiants internationaux ; identifier les besoins d’apprentissage et mettre en oeuvre des stratégies qui répondent à ces besoins.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

An Expert Panel of the Royal Society of Canada and a Select Committee of the Québec National Assembly both recently recommended the issuance of permissive guidelines for the exercise of prosecutorial discretion on voluntary euthanasia and assisted suicide and “medical aid in dying” respectively. It seems timely, therefore, to propose a set of offence-specific guidelines for how prosecutorial discretion should be exercised in cases of voluntary euthanasia and assisted suicide in Canadian provinces and territories. We take as our starting point the only existing guidelines of this sort currently in force in the world (i.e. the British Columbia Guidelines, and the England and Wales Guidelines). In light of certain concerns we have with these guidelines, we outline an approach to constructing guidelines for Canadian jurisdictions that begins with identifying three guiding principles we argue are appropriate for this purpose (respect for autonomy, the need for high-quality prosecutorial decision making, and the importance of public confidence in that decision making), and ends with a concrete and detailed set of proposed guidelines. The paper is consistent with, but also extends, the work of the Royal Society of Canada Expert Panel on End of Life Decision Making. Un panel d’expert de la Société Royale du Canada et une Commission spéciale de l’Assemblée nationale du Québec ont tous les deux récemment recommandé que soit émises des directives permettant exercice d’un pouvoir de poursuite discrétionnaire concernant l’euthanasie et le suicide assisté et « l’assistance médicale pour mourir », respectivement. Il semble donc à propos de proposer une série de directives spécifiques aux offenses sur la façon dont le pouvoir de poursuite discrétionnaire dans les territoires et provinces canadiennes serait appliqué dans les cas d’euthanasie et de suicide assisté. Nous avons pris comme point de départ les seules directives de la sorte existant déjà (c’est-à-dire celle de la Colombie-Britannique et de l’Angleterre et du Pays de Galles). Par contre, compte tenu de certaines de nos réserves concernant ces directives, nous avons ensuite établi les grandes lignes d’une approche permettant de mettre sur pied des directives pour les juridictions canadiennes, qui débute par l’identification de trois principes de base qui sont selon nous appropriées à cette fin (respect de l’autonomie, besoin pour une grande qualité de prise de prise de décision du poursuivant et la confiance du public envers cette prise de décision) pour se terminer par une série de directives concrètes et détaillées. Le présent document est compatible avec le travail de la Société royale du Canada tout en en augmentant la portée.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Parabolic Trough Concentrators (PTC) are the most proven solar collectors for solar thermal power plants, and are suitable for concentrating photovoltaic (CPV) applications. PV cells are sensitive to spatial uniformity of incident light and the cell operating temperature. This requires the design of CPV-PTCs to be optimised both optically and thermally. Optical modelling can be performed using Monte Carlo Ray Tracing (MCRT), with conjugate heat transfer (CHT) modelling using the computational fluid dynamics (CFD) to analyse the overall designs. This paper develops and evaluates a CHT simulation for a concentrating solar thermal PTC collector. It uses the ray tracing work by Cheng et al. (2010) and thermal performance data for LS-2 parabolic trough used in the SEGS III-VII plants from Dudley et al. (1994). This is a preliminary step to developing models to compare heat transfer performances of faceted absorbers for concentrating photovoltaic (CPV) applications. Reasonable agreement between the simulation results and the experimental data confirms the reliability of the numerical model. The model explores different physical issues as well as computational issues for this particular kind of system modeling. The physical issues include the resultant non-uniformity of the boundary heat flux profile and the temperature profile around the tube, and uneven heating of the HTF. The numerical issues include, most importantly, the design of the computational domain/s, and the solution techniques of the turbulence quantities and the near-wall physics. This simulation confirmed that optical simulation and the computational CHT simulation of the collector can be accomplished independently.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

According to some embodiments, the present invention provides a novel photovoltaic solar cell system from photovoltaic modules that are vertically arrayed in a stack format using thin film semiconductors selected from among org. and inorg. thin film semiconductors. The stack cells may be cells that are produced in a planar manner, then vertically oriented in an angular form, also termed herein tilted, to maximize the light capturing aspects. The use of a stack configuration system as described herein allows for the use of a variety of electrode materials, such as transparent materials or semitransparent metals. Light concn. can be achieved by using fresnel lens, parabolic mirrors or derivs. of such structures. The light capturing can be controlled by being reflected back and forth in the photovoltaic system until significant quantities of the resonant light is absorbed. Light that passes to the end and can be reflected back through the device by beveling or capping the end of the device with a different refractive index material, or alternatively using a reflective surface. The contacting between stacked cells can be done in series or parallel. According to some embodiments, the present invention uses a concentrator architecture where the light is channeled into the cells that contain thermal fluid channels (using a transparent fluid such as water) to absorb and hence reduce the thermal energy generation.