2,096,870 research outputs found
474: lighting and thermal performance of innovative shading devices: new insights into their aesthetics and control in a Mediterranean climate
Get PDFWith a view towards minimising energy demand for cooling and artificial lighting in buildings, this paper evaluates innovative shading devices and how they can balance a generous degree of control mastering seasonal natural light with thermal gains in a typical Mediterranean climate such as Malta. The study evaluates the potential success (or failure) of such shading devices, from both their aesthetic and functional perspectives, as part of a passive design strategy adopted by the architect. Through environmental design and solar geometry, experimental simulations were generated in architectural science modelling software package Ecotect© developed by Andrew Marsh. Moreover a novel computer model termed Solar Control© was developed by the authors in order to assist architects at an early stage during design.peer-reviewe
Epidermal Passive RFID Strain Sensor for Assisted Technologies
Get PDFAn epidermal passive wireless strain sensor using RFID tags is presented. The tag is intended to detect eyebrow or neck skin stretch where paraplegic patients have the capability to tweak facial muscles. The tag is designed on a Barium Titanate loaded PDMS substrate and is assessed to demonstrate the strain gauge sensitivity and repeatability as a function of skin stretch
Geothermal ground heat exchangers in Malta : thermal performance assessment of infill grouts
Get PDFThe aim of this paper was to assess the thermal conductivity of proprietary grout mixes versus local ones in Malta. Ground source heat pump (GSHP) systems consume 75% less electricity than conventional environmental control systems and have lower maintenance costs. On the other hand the installation costs of GSHPs are comparatively higher. Attention has therefore been focused to try to lower the costs of installing the borehole heat exchange system. The grout is one of the key factors that influence the efficiency of ground source heat pumps, being the principal conductive medium to the natural terrain. This paper explores the variations in the thermal conductivity of different sand-cement grouts. It compares and evaluates options for the suitability of these materials for backfilling vertical boreholes of ground heat exchangers. In this study sixteen different sand-cement grouts have been designed, evaluated and compared with materials, which have been conventionally used to fulfil this purpose. Imported silica sand and local sand mixes were formulated, tested and compared so that the potential use of local sands could be closely examined. Output results prove that local sand-cement grouts improve thermal conductivity values by 27% and are also 17% less expensive when compared to silica sand-cement and bentonite grouts. This win-win scenario points towards improvements in both in thermal conductivity and cost effectiveness when using local resources.peer-reviewe
FM airborne passive radar
Get PDFThe airborne application of Passive Bistatic Radar (PBR) is the latest evolution of the now established international interest in passive radar techniques. An airborne passive system is cheaper to construct, easier to cool, lighter and requires less power than a traditional active radar system. These properties make it ideal for installation on an Unmanned Aerial Vehicle (UAV), especially for the next generation of Low Observable (LO) UAVs, complementing the platforms LO design with an inherently Low Probability of Intercept (LPI) air-to-air and air-to-ground sensing capability. A comprehensive literature review identified a lack of practical and theoretical research in airborne passive bistatic radar and a quantitative model was designed in order to un- derstand the theoretical performance achievable using a hypothetical system and FM as the illuminator of opportunity. The results demonstrated a useable surveillance volume, assuming conservative estimates for the receiver parameters and allowed the scoping and specification of an airborne demonstrator system. The demonstrator system was subsequently designed and constructed and flown on airborne experiments to collect data for both air-to-air and air-to-ground operation analysis. Subsequent processing demonstrated the successful detection of air targets which correlated with the actual aircraft positions as recorded by a Mode-S/ADS-B receiver. This is the first time this has been conclusively demonstrated in the literature. Doppler Beam Sharpening was used to create a coarse resolution image allowing the normalised bistatic clutter RCS of the stationary surface clutter to be analysed. This is the first time this technique has been applied to an airborne passive system and has yielded the first quantitive values of normalised bistatic clutter RCS at VHF. This successful demonstration of airborne passive radar techniques provides the proof of concept and identifies the key research areas that need to be addressed in order to fully develop this technology
Passive design, it's a natural.
No full text"SERI/SP ; 432-521."Issued April 1980."Produced for the U.S. Dept. of Energy National Passive/Hybrid Heating and Cooling Program by the Passive Technology Program of the Solar Energy Research Institute."Bibliography: p. 20-21.Mode of access: Internet
Passive Earth Pressure in Narrow Cohesive-Frictional Backfills
No full textA narrow backfill zone is formed when retaining walls are built near existing stabilized structures (e.g., rock faces). In such circumstances, the classical passive earth pressure coefficient is no longer applicable, and a correction factor is required for the design. This paper aims to develop analytical solutions for estimating the passive earth pressure problem of narrow cohesive-frictional backfills behind retaining walls. The novel arched differential element method considers both effects of the horizontal shear stress in backfills and the soil arching, and it is employed to estimate the passive earth pressure distribution along with wall depth. The solutions are compared against those published experimental data, analytical approaches, and finite-element limit analysis solutions. The factors influencing the distribution of passive earth pressure are also undertaken using a series of parametric studies. To implement the derived solutions into a routine design, a modified practical design equation is presented following the standard Coulomb's solutions. This work provides a theoretical guideline for the initial design of retaining walls with narrow soils, and it should be of great interest to practitioners. Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Geo-engineerin
Goodbye Passive House, Hello Energy Flexible Building?
No full textThe volume uptake of highly energy-efficient buildings is challenged by transformations in the energy system and the introduction of demand response strategies. In the near future buildings will be able to manage their demand and generation according to local climate conditions, user needs and variable energy prices. As buildings become prosumers of electricity and heat in intelligent networks, questions arise about the future and the need of highly energy-efficient building concepts, such as passive houses.Do suppliers in the passive house sector experience a need to adopt such energy flexible buildings? To understand this need, a supply side research was done using the members of a Belgian passive house network as a feedback group. The research used three distinct approaches for exploring barriers, opportunities and knowledge needs that companies perceive. A questionnaire explored the experience that Belgian supply side actors have with energy flexible buildings. This was followed by a focus group discussion with passive house and smart grid professionals and a business model development exercise with passive house suppliers.The research unravels a positive attitude in the passive house sector towards energy flexible buildings. Innovators are keen to adopt the concept of energy flexible buildings. The research shows that the market development towards energy flexible buildings cannot be ignored by suppliers in the construction sector if they want to stay active as frontrunners in energy efficiency. A shift in knowledge needs is observed from passive houses and energy positive buildings towards designing and using buildings as active component within smart grids. A need to develop a local knowledge network for energy flexible buildings was specified.Further research and particularly exemplary projects are needed to understand how highly energy-efficient buildings such as passive houses can be an active storage component in smart cities. An international research programme in the framework of the International Energy Agency will explore the definition of, and indicators for, energy flexible buildings. Meanwhile demonstration buildings and testing facilities will be installed in various European countries. The need for adapted business models and certification of energy flexible buildings will be explored. Knowledge will be disseminated in local platforms.Accepted Author Manuscript. The contribution relates to the Dutch national participation in the working group of the IEA EBC Annex 67 Energy Flexible Buildings.OLD Housing Quality and Process Innovatio
A note on non-canonical passives : the case of the get-passive
No full textIn many languages, a passive-like meaning may be obtained through a noncanonical passive construction. The get passive (1b) in English, the se faire passive (2b) in French and the kriegen passive (3b) in German represent typical manifestations. This squib focuses on the behavior of the get-passive in English and discusses a number of restrictions associated with it as well as the status of get
Passive house networks: How can they deliver?
No full textThis paper examines experiences with the diffusion of the passive house concept, applied to the situation of ‘emerging’ countries like Belgium and the Netherlands. Adopter categories considering the passive house concept are defined. A marketing study based on Rogers’ theory of diffusion of innovations highlights the characteristics of actors leading to technological and process innovation. The paper draws conclusions on the preferred role of passive house networks.OTB Research Institut
From 3ptl-to passive : incipient, emergent and established passives
Get PDFThis paper explores, in some detail, the development of third person plural impersonal constructions into passive ones with the aim of determining the conditions most conducive to the emergence of a canonical passive, i.e. one which is both promotional (with an overt lexical subject) and agentive (with an overt agent). On the basis of cross-linguistic data it is argued that the required conditions are, on the one hand, the existence of a morphological alignment which does not distinguish between the O of a transitive clause and the S of a passive one and, on the other hand, the availability of highly grammaticalized third person plural impersonals, i.e. ones which can be used in episodic contexts and with different types of agents, among them individual and specific ones. The documented rarity of promotional passives originating from third person plural impersonal constructions is attributed to the rarity of the coincidence of the above two sets of independent factors
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