901 resultados para accelerator driven transmutation
Resumo:
Exploiting solar energy technology for both heating and cooling purposes has the potential of meeting an appreciable portion of the energy demand in buildings throughout the year. By developing an integrated, multi-purpose solar energy system, that can operate all twelve months of the year, a high utilisation factor can be achieved which translates to more economical systems. However, there are still some techno-economic barriers to the general commercialisation and market penetration of such technologies. These are associated with high system and installation costs, significant system complexity, and lack of knowledge of system implementation and expected performance. A sorption heat pump module that can be integrated directly into a solar thermal collector has thus been developed in order to tackle the aforementioned market barriers. This has been designed for the development of cost-effective pre-engineered solar energy system kits that can provide both heating and cooling. This thesis summarises the characterisation studies of the operation of individual sorption modules, sorption module integrated solar collectors and a full solar heating and cooling system employing sorption module integrated collectors. Key performance indicators for the individual sorption modules showed cooling delivery for 6 hours at an average power of 40 W and a temperature lift of 21°C. Upon integration of the sorption modules into a solar collector, measured solar radiation energy to cooling energy conversion efficiencies (solar cooling COP) were between 0.10 and 0.25 with average cooling powers between 90 and 200 W/m2 collector aperture area. Further investigations of the sorption module integrated collectors implementation in a full solar heating and cooling system yielded electrical cooling COP ranging from 1.7 to 12.6 with an average of 10.6 for the test period. Additionally, simulations were performed to determine system energy and cost saving potential for various system sizes over a full year of operation for a 140 m2 single-family dwelling located in Madrid, Spain. Simulations yielded an annual solar fraction of 42% and potential cost savings of €386 per annum for a solar heating and cooling installation employing 20m2 of sorption integrated collectors.
Resumo:
Vehicle activated signs (VAS) display a warning message when drivers exceed a particular threshold. VAS are often installed on local roads to display a warning message depending on the speed of the approaching vehicles. VAS are usually powered by electricity; however, battery and solar powered VAS are also commonplace. This thesis investigated devel-opment of an automatic trigger speed of vehicle activated signs in order to influence driver behaviour, the effect of which has been measured in terms of reduced mean speed and low standard deviation. A comprehen-sive understanding of the effectiveness of the trigger speed of the VAS on driver behaviour was established by systematically collecting data. Specif-ically, data on time of day, speed, length and direction of the vehicle have been collected for the purpose, using Doppler radar installed at the road. A data driven calibration method for the radar used in the experiment has also been developed and evaluated. Results indicate that trigger speed of the VAS had variable effect on driv-ers’ speed at different sites and at different times of the day. It is evident that the optimal trigger speed should be set near the 85th percentile speed, to be able to lower the standard deviation. In the case of battery and solar powered VAS, trigger speeds between the 50th and 85th per-centile offered the best compromise between safety and power consump-tion. Results also indicate that different classes of vehicles report differ-ences in mean speed and standard deviation; on a highway, the mean speed of cars differs slightly from the mean speed of trucks, whereas a significant difference was observed between the classes of vehicles on lo-cal roads. A differential trigger speed was therefore investigated for the sake of completion. A data driven approach using Random forest was found to be appropriate in predicting trigger speeds respective to types of vehicles and traffic conditions. The fact that the predicted trigger speed was found to be consistently around the 85th percentile speed justifies the choice of the automatic model.
Resumo:
Consideration of a wide range of plausible crime scenarios during any crime investigation is important to seek convincing evidence and hence to minimize the likelihood of miscarriages of justice. It is equally important for crime investigators to be able to employ effective and efficient evidence-collection strategies that are likely to produce the most conclusive information under limited available resources. An intelligent decision support system that can assist human investigators by automatically constructing plausible scenarios, and reasoning with the likely best investigating actions will clearly be very helpful in addressing these challenging problems. This paper presents a system for creating scenario spaces from given evidence, based on an integrated application of techniques for compositional modelling and Bayesian network-based evidence evaluation. Methods of analysis are also provided by the use of entropy to exploit the synthesized scenario spaces in order to prioritize investigating actions and hypotheses. These theoretical developments are illustrated by realistic examples of serious crime investigation.
Resumo:
The specification of Quality of Service (QoS) constraints over software design requires measures that ensure such requirements are met by the delivered product. Achieving this goal is non-trivial, as it involves, at least, identifying how QoS constraint specifications should be checked at the runtime. In this paper we present an implementation of a Model Driven Architecture (MDA) based framework for the runtime monitoring of QoS properties. We incorporate the UML2 superstructure and the UML profile for Quality of Service to provide abstract descriptions of component-and-connector systems. We then define transformations that refine the UML2 models to conform with the Distributed Management Taskforce (DMTF) Common Information Model (CIM) (Distributed Management Task Force Inc. 2006), a schema standard for management and instrumentation of hardware and software. Finally, we provide a mapping the CIM metamodel to a .NET-based metamodel for implementation of the monitoring infrastructure utilising various .NET features including the Windows Management Instrumentation (WMI) interface.
Resumo:
As a result of urbanization, stormwater runoff flow rates and volumes are significantly increased due to increasing impervious land cover and the decreased availability of depression storage. Storage tanks are the basic devices to efficiently control the flow rate in drainage systems during wet weather. Presented in the paper conception of vacuum-driven detention tanks allows to increase the storage capacity by usage of space above the free surface water elevation at the inlet channel. Partial vacuum storage makes possible to gain cost savings by reduction of both the horizontal area of the detention tank and necessary depth of foundations. Simulation model of vacuum-driven storage tank has been developed to estimate potential profits of its application in urban drainage system. Although SWMM5 has no direct options for vacuum tanks an existing functions (i.e. control rules) have been used to reflect its operation phases. Rainfall data used in simulations were recorded at raingage in Czestochowa during years 2010÷2012 with time interval of 10minutes. Simulation results gives overview to practical operation and maintenance cost (energy demand) of vacuum driven storage tanks depending of the ratio: vacuum-driven volume to total storage capacity. The following conclusion can be drawn from this investigations: vacuum-driven storage tanks are characterized by uncomplicated construction and control systems, thus can be applied in newly developed as well as in the existing urban drainage systems. the application of vacuum in underground detention facilities makes possible to increase of the storage capacity of existing reservoirs by usage the space above the maximum depth. Possible increase of storage capacity can achieve even a few dozen percent at relatively low investment costs. vacuum driven storage tanks can be included in existing simulation software (i.e. SWMM) using options intended for pumping stations (including control and action rules ).
Resumo:
Libraries are caught in the middle—between static or shrinking budgets on one hand and ever-expanding user needs on the other. How did we get here, and where do we go from here? This paper will offer two perspectives: Part I will present survey results about changing Library purchasing habits in light of changing formats, access, business models and user demands. Data from a previous survey on this topic will be compared and updated. Pricing trends and possible futures will be discussed. Part II will briefly trace the history of libraries’ roles in scholarly communication and connecting learners with knowledge. From there, we show an example of phasing in a patron-driven / demand-driven and short-term loan e-book program, complete with incorporating these tools in library instruction, research, and portable device loadability for field work.
Resumo:
It has been said that international assignments are traditionally “demand- driven” (DD) that is a way of expatriation of executives focused on control, solution of problems and transference of tacit knowledge. Besides that, according to the international literature, “adjustment” is the determinant factor for success in overseas assignments and Japan usually sends their own executives to subsidiaries in other developing countries for “DD” purpose. However, according to the initial empirical study and in-depth interviews, it seems that Japanese expatriate managers in Brazil were sent to learn how to adjust the local staff to their philosophy instead of adjust themselves to a new complete scenario. This paper found that “adjustment” would not be fundamental for Japanese expatriate manager’s success in their assignments to Brazil, since they were under a special “learning-driven” type of expatriation process. This paper also highlights the challenges of the Japanese expatriate managers in Brazil and their contribution to the development of local staff under the internationalization process.
Resumo:
Existe inumeras definições de cultura. A cultura é um tema complexo que pode ser considerado em inumeros aspectos.Porém uma importante caracteristica que diferencia signos de simbolos é que todos os símbolos são criados subjetivamente e saõ investidos de um tipo particularde de significado, eles buscam explicar um significado, significado esse que vai formar sujeitos ou definir tais padroes de cultura, da qual resutaria uma representação fiel do significado explicitamente tratado