196,050 research outputs found
Power Quality As An Opportunity to Implement the Productivity and to Reduce the Costs
No full textThe article describes the hardware and software of the instrument placed in some European countries able to collect Power Quality (PQ) data. These instruments are provided by one of the bigger UPS farmer in the world. The collected data have been analyzed by Roma Tre University that has elaborated some statistical evaluation of the European PQ. Some economical evaluation on the industrial productivity, connected with the lack of PQ, are also presented. It is also shown a possible creation, in the future, of new corporations able to face PQ problems with the aim to provide new kind of service for those customers particularly sensible to PQ
Power Quality Measurements in Telecommunication Exchanges
No full textThis work shows an example of power quality (PQ)
data of four important telecommunication sites placed in Rome,
Italy. The data are collected, elaborated and analyzed by four
self made instruments developed for this purpose and inserted in
four automatic telecommunication exchanges kindly at our
disposal by TELECOM, the most important Italian
telecommunication company.
The analysis shows the active and reactive power consumption
and, for one site, the harmonic distortion
Does spontaneous respiration alter pulmonary artery input impedance?
No full textThe aim of this study was to determine whether spontaneous respiration influences pulmonary artery input impedance, a question that has received little attention in the literature. Impedance values were assessed during three different phases of the respiratory cycle, namely inspiration, expiration and postexpiration (i.e. the null respiratory flow period between expiration and the next inspiration) in five anaesthetized spontaneously breathing dogs, Firstly, impedance values during postexpiration were taken as the reference baseline, and compared with values obtained during inspiration and expiration, Then, differences between values in inspiration and in expiration were tested, taking impedance during inspiration as the baseline, Differences with respect to postexpiration were found for three parameters of input impedance: input resistance, characteristic impedance, and the frequency at the first zero-crossing of the impedance phase from negative to positive values (fcross), Input resistance was significantly lower in inspiration (85% of the baseline), characteristic impedance was significantly greater in inspiration and in expiration (112 and 119% respectively), and fcross was significantly lower in expiration (89%), By contrast, only input resistance differed significantly when inspiration was compared to expiration. Therefore, spontaneous respiration was shown to influence input impedance significantly, The observed changes in characteristic impedance and fcross might be explained by a stiffening of the pulmonary artery wall, due to neural and/or mechanical factors, during inspiration and expiration
Smart Grid: What’s news?
No full textAs a direct consequence of the increasing demand. of energy and the need to decrease pollution in order to cope. with global warming, political, industrial and scientific interests. have combined to understand the way ICT technologies can. help to review all phases of energetic cycle, from generation. (through renewable sources), to accumulation and. transportation, until distribution. The union between ICT and. energy is usually identified as “Smart Grid”, to emphasize an. expectation change in what will be the Power Grid of the. incoming future. The aim of this study is to give some ideas. about the experimentation of new techniques of energy. acquisition through renewable sources (solar, chp, wind, etc.).. These techniques would guarantee more accessible prices for. production, improving performances, the overcome of those. constraints that did not allow the exploitation of potential. energy capacity of renewable sources. This grid will be made of. devices forming a control cycle that will check the station of. energy generation as much as the behaviour of single. consumers
Power Quality in Telecommunication Exchanges Delivery Points
No full textPower quality is an important subject to correctly
dimension protection devices and back up power systems for next
generation of telecommunication network. In this paper it is
presented an overview of some power quality data obtained using
integrated instruments put inside Chloride's UPS, widely
distributed in the world and active for quite a few years, allow
statistical evaluations to derive some important convictions about
the power quality situation, which are the electrical energy
parameters particularly important for the design of new
generation tIc apparatuses. The article is focused on the Italian
situation and in detail analyzes the mains failures for each Italian
region
The influence of support conditions on short- and long-term track behaviour
No full textRailway track support conditions are known to deeply affect the dynamic performance of vehicle-track interaction, influencing the state of the track system both in the short and in the long term. Exactly how much and how is not precisely understood and the notion of track stiffness, although thought to be a key parameter of the track quality, is currently not being monitored systematically. This paper seeks to analyse the influence on the ballast behaviour of track vertical stiffness and especially its spatial non-uniformity, using available experimental data measured at different sites. Mathematical models are developed and the effectiveness of applying under sleeper pads is also investigated. Finally, an iterative procedure based on Guerin’s settlement law is used to take into account the long-term behaviour of the ballast. Such models can help to understand mitigation solutions as well as predicting track quality evolution over time
Assessing the Role of Longitudinal Variability of Vertical Track Stiffness in the Long-Term Deterioration
No full textThe performance of the railway system in terms of dynamic loading is depending mainly on the track support conditions. Usually, the track stiffness is used as the main parameter to describe the support conditions and is defined as the ratio of the load applied to the rail over the vertical rail deflection. Ideally that parameter is constant, but in reality this condition is very unlikely to happen. Therefore, there is non-uniform track loading and non-uniform track deterioration, generally known as differential settlement, leading to a general increment of maintenance and renewal costs.
Even if it plays a major role in the system dynamics, it is very difficult to derive a measure of the actual variability of the track stiffness along the railway. There are many techniques to experimentally acquire those values, for example using the Falling Weight Deflectometer (FWD) equipment or the Swedish Rolling Stiffness Measurement Vehicle (RSDV) measuring train. However, these measures are usually very costly and limited in extension. The measuring data may not be long enough to be statistically representative, and thus it is not possible to have a clear correlation between the physical properties of the railway system and its long-term behaviour without running simulations with extended track data.
The main aim of the present study is to assess the role of longitudinal variability of the vertical track stiffness in the long-term behaviour of the track degradation. In particular, new sets of track stiffness data which can appropriately reproduce the statistical properties of the real ones will be simulated. Then, the variability of the outputs of the vehicle dynamic model depending on the variability in the inputs will be statistically analysed. This is inspired in past research that highlighted the role of vertical stiffness in track deterioration, but not looking at the actual longitudinal variability of vertical stiffness as a contributing factor
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
Indoor lighting fault detection and diagnosis using a data fusion approach
No full textIn this paper, an innovative and automated fault detection and diagnosis (FDD) approach based on high-level correlation rules in order to improve reliability, safety and efficiency of a supervised building is presented. The proposed method is based on the data fusion of different measurements, using their fuzzification and aggregation through suitable operators, in order to get dimensionless severity indicators able to diagnose faults and to identify the possible causes (ranked according their severity) generating them. Thus, a set of possible anomalies that can occur in a building and the correlation with measured physical quantities were identified. Experimentation of this FDD technique was applied to indoor lighting of a real office building. The proposed method was validated over a onemonth period with the aim of detecting anomalous consumption events, considering when and in which circumstances they occurred. After this stage, the FDD system was performed in real time operatio
"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.
No full text"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states.
By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement.
To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports
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