Search results for "Exchange"
showing 10 items of 2035 documents
Using semantics to facilitate data integration of offshore wind farms
2012
Operation and maintenance play an important role in extracting power from the wind, especially, in offshore wind energy where wind farms are located far off the shore and under harsh weather conditions. Improved operation and maintenance is likely to reduce costs as well as hazard exposure of the employees. Implementation of advanced information technology is thus crucial for operating offshore wind farms effectively and efficiently and hence improves operation and maintenance. However, information availability and reliability are key issues for their use in the offshore wind domain. In addition, the semantic of information has not been exploited thoroughly. This paper describes the develop…
PEM Fuel Cell System Model Predictive Control and real-time operation on a power emulator
2010
Fuel Cell Systems (FCS) seem to be among the most reliable devices to produce clean energy, although they still suffer for many problems, mostly related to the fragility of the Polymer Electrolyte Membrane (PEM). Particularly, this paper focuses on the oxygen starvation, that leads both a decrease of the FCS performance and a shortening in the FCS lifetime. The purpose is to use the Model Predictive Control (MPC) and its capacity of accounting for linear constraints for managing the air system without risking to damage the fuel cell. Two control inputs and no static feed-forward actions have been used. Results show that the MPC is able to avoid the oxygen starvation, even with a sudden incr…
High performance Athletes dual career support opportunities in the context of the European Union
2015
This article aims to provide an overview of high performance athletes - students dual-career support opportunities in the European Union, in order to create dual career support system in Latvia. The paper provides an explanation of terms, and analyzes the UK, Ireland, Germany, Belgium and other countries' experience in the dual career. In the process is created a comparative overview of the possibilities for support in several European countries. High-performance athletes main types of support are flexible exam schedule, individual study plan, consultations with lecturers, distance learning studies (e-learning), the mentor's advice, and reduced requirements for entrance exams. In Latvia the…
Integrated Mathematical Model of Proton Exchange Membrane Fuel Cell Stack (PEMFC) with Automotive Synchronous Electrical Power Drive
2008
In this work, the mathematical dynamical model of a PEMFC stack has been developed and implemented in Matlab environment. Lots of simulations have been executed in two different load conditions. Firstly with a resistive load and finally with a synchronous electrical power drive in automotive load conditions. The innovation in this field consists in the integration in PEMFC stack mathematical dynamic model of a synchronous electrical power drive one for automotive purposes. As regards the simulations with a synchronous electrical power drive, the complete mathematical model allows to evaluate the PEMFC stack performances and electrochemical efficiency. This represents a useful design tool.
Application of a new wireless instrument to characterize thermal properties of ground coupled heat exchangers
2010
Abstract In this work, we report the design and laboratory test of a new instrument to measure the temperature of the heat transfer fluid along the borehole exchanger (BHE) by autonomous wireless sensor. The instrument consists of a device, which inserts and extracts miniaturized wireless sensors in the borehole with a mechanical subsystem, composed by a circulating pump and two valves. This device transmits to the sensors the acquisition configuration, and downloads the temperature data measured by the sensor along its way through the borehole heat exchanger. Each sensor is included in a sphere of 25 mm diameter and contains a transceiver, a microcontroller, a temperature sensor and a powe…
Real time assessment of hand-arm vibration system based on capacitive MEMS accelerometers
2012
Vibrations are a well known potential cause of health diseases and therefore constitute a main concern for the safety of workers in a large number of activities. In order to prevent health hazards, national and international institutions have issued laws and directives which establish recommended limits to the workers' exposure to vibrations during operations. Consequently, if the amount of adsorbed vibration exceeds the allowable daily limits the worker has to stop his job. Recent wireless sensing and communicating technologies can effectively be employed for such purpose, allowing to develop monitoring customized devices at affordable cost which could be easily employed during the workers…
Barriers to Integrated Marketing Communications: The Case of Latvia (small markets)
2012
Abstract No promotional tool should be used in isolation or without regard to the others; hence there is a trend toward integrated marketing communications. Many conclusions of researchers and most of the studies justify the effectiveness of the IMC and point to multiple advantages in comparison to the classical MC. In comparison to the classical MC, the IMC also in small markets declare exigency and ensure higher effectiveness. But the development and application of the IMC also has several problems or barriers. The purpose of this study is to investigate barriers to Integrated Marketing Communications in Latvian market (small markets). According to accomplished interrogation, the most imp…
FPGA implementation of a fuel cell emulator
2010
Fuel cell based systems are usually tested with the aid of high-cost and complex auxiliary devices. A fuel cell emulator is an attractive solution for preliminary downward system test. The emulator replaces the effective power source saving cost, volume and hydrogen reserve still ensuring high-accuracy of test results. The use of a highperformance fuel cell model is essential for a successful conclusion of the overall design process. Although the proposed emulator is suitable for each fuel cell type and power level, a 10W Proton Exchange Membrane Fuel Cell emulator is designed and tested. An FPGA based controller models the fuel cell steady-state and dynamic behaviour, including temperature…
A measurement methodology for monitoring a CHCP pilot plant for an office building
2003
Abstract In Mediterranean areas, climate conditions determine quite equal demand both for thermal and cooling energy. The possibility to convert a cooling demand in thermal one through an absorption chiller allows to extend widely the number of running hours of a cogeneration plant. A trigeneration pilot plant for two office building is described, in which an integrated lay-out includes a NG prime mover with heat exchanger, an absorption chiller and a reversible heat pump. The pilot plant is completed and pre-running test were performed. Different fluid dynamics parameters will be monitored, in order to build the actual cumulative curve for thermal power. The measurement methodology is also…
Unfolding Cyberspace: Cyberplaces of the Contrade and the Style of Representation in the Global Arena
2017
This chapter shows that, in the online representation of the contrade of Siena, the global level is not opposed to the local but is, instead, a particular way in which the local is represented. The method of placing their community on the global stage is that of an idealised inhabitation, one which also allows them to keep control over the formation of their collective identities. Furthermore, it shows that in the globalised world, the neighbourhoods of Siena encounter a global interest in their way of life which has made them alter their modes of self-representation . In order to position themselves in both local and global contexts, they have chosen to use the World Wide Web to present th…