950 resultados para Electric machinery.


Relevância:

20.00% 20.00%

Publicador:

Resumo:

A direct-driven permanent magnet synchronous machine for a small urban use electric vehicle is presented. The measured performance of the machine at the test bench as well as the performance over the modified New European Drive Cycle will be given. The effect of optimal current components, maximizing the efficiency and taking into account the iron loss, is compared with the simple id=0 – control. The machine currents and losses during the drive cycle are calculated and compared with each other.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Findings by our group have shown that the dorsolateral telencephalon of Gymnotus carapo sends efferents to the mesencephalic torus semicircularis dorsalis (TSd) and that presumably this connection is involved in the changes in electric organ discharge (EOD) and in skeletomotor responses observed following microinjections of GABA A antagonist bicuculline into this telencephalic region. Other studies have implicated the TSd or its mammalian homologue, the inferior colliculus, in defensive responses. In the present study, we explore the possible involvement of the TSd and of the GABA-ergic system in the modulation of the electric and skeletomotor displays. For this purpose, different doses of bicuculline (0.98, 0.49, 0.245, and 0.015 mM) and muscimol (15.35 mM) were microinjected (0.1 µL) in the TSd of the awake G. carapo. Microinjection of bicuculline induced dose-dependent interruptions of EOD and increased skeletomotor activity resembling defense displays. The effects of the two highest doses showed maximum values at 5 min (4.3 ± 2.7 and 3.8 ± 2.0 Hz, P < 0.05) and persisted until 10 min (11 ± 5.7 and 8.7 ± 5.2 Hz, P < 0.05). Microinjections of muscimol were ineffective. During the interruptions of EOD, the novelty response (increased frequency in response to sensory novelties) induced by an electric stimulus delivered by a pair of electrodes placed in the water of the experimental cuvette was reduced or abolished. These data suggest that the GABA-ergic mechanisms of the TSd inhibit the neural substrate of the defense reaction at this midbrain level.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The objective of this thesis was to study the effect of pulsed electric field on the preparation of TiO2 nanoparticles via sol-gel method under the visible light irradiation. The literature part introduces properties of different TiO2 crystal forms and principle of photocatalysis. It was expected that pulsed electric field would have an influence on degradation for oxalic acid and formic acid. TiO2 samples were prepared by using three frequencies (50Hz, 294Hz, and 963Hz) and two treatment times (12 minutes and 24 minutes) of pulsed electric field. The photocatalytic activities of TiO2 samples produced with sol-gel method were also compared with the TiO2 particles made by previous study and with the commercial TiO2 powder Aeroxide® (Evonic Degussa GmbH) at the same condition. Results show that pulsed electric field does have an effect on degradation for oxalic acid and formic acid. Generally, higher photocatalytic activities for oxalic acid and formic acid were obtained with lower frequency and longer treatment time of pulsed electric field.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Dengue virus (DV)-induced changes in the host cell protein synthesis machinery are not well understood. We investigated the transcriptional changes related to initiation of protein synthesis. The human hepatoma cell line, HepG2, was infected with DV serotype 2 for 1 h at a multiplicity of infection of one. RNA was extracted after 6, 24 and 48 h. Microarray results showed that 36.5% of the translation factors related to initiation of protein synthesis had significant differential expression (Z-score ≥ ±2.0). Confirmation was obtained by quantitative real-time reverse transcription-PCR. Of the genes involved in the activation of mRNA for cap-dependent translation (eIF4 factors), eIF4A, eIF4G1 and eIF4B were up-regulated while the negative regulator of translation eIF4E-BP3 was down-regulated. This activation was transient since at 24 h post-infection levels were not significantly different from control cells. However, at 48 h post-infection, eIF4A, eIF4E, eIF4G1, eIF4G3, eIF4B, and eIF4E-BP3 were down-regulated, suggesting that cap-dependent translation could be inhibited during the progression of infection. To test this hypothesis, phosphorylation of p70S6K and 4E-BP1, which induce cap-dependent protein synthesis, was assayed. Both proteins remained phosphorylated when assayed at 6 h after infection, while infection induced dephosphorylation of p70S6K and 4E-BP1 at 24 and 48 h of infection, respectively. Taken together, these results provide biological evidence suggesting that in HepG2 cells DV sustains activation of the cap-dependent machinery at early stages of infection, but progression of infection switches protein synthesis to a cap-independent process.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This study proposes alternatives to the current methods of processing round-cooked lobster. The paralyzation of lobsters with direct electric shock consumes 10.526 x 10-3 kWh, which is significantly less than the 11 kWh required by the traditional thermal-shock method (based on 60 kg of lobsters). A better weight gain was obtained by immersion of paralyzed lobsters in brine before cooking. Systematic trials combining 3, 6, or 9% brine concentrations with immersion periods of 15, 30, or 45 minutes were performed in order to determine the best combinations. A mathematical model was designed to predict the weight gain of lobsters of different sizes in any combination of treatments. For small lobsters, a 45 minutes immersion in 6% brine gave the best response in terms of weight gain (4.7%) and cooking produced a weight loss of only 1.34% in relation to fresh lobster weight. For medium-sized lobsters, a 45 minutes immersion in 9% brine produced a weight gain of 2.64%, and cooking a weight gain of 1.08%. For large lobsters, a 45 minutes immersion in 6% brine produced a weight gain of 3.87%, and cooking a weight gain of 1.62%.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The application of VSC-HVDC technology throughout the world has turned out to be an efficient solution regarding a large share of wind power in different power systems. This technology enhances the overall reliability of the grid by utilization of the active and reactive power control schemes which allows to maintain frequency and voltage on busbars of the end-consumers at the required level stated by the network operator. This master’s thesis is focused on the existing and planned wind farms as well as electric power system of the Åland Islands. The goal is to analyze the wind conditions of the islands and appropriately predict a possible production of the existing and planned wind farms with a help of WAsP software program. Further, to investigate the influence of increased wind power it is necessary to develop a simulation model of the electric grid and VSC-HVDC system in PSCAD and examine grid response to different wind power production cases with respect to the grid code requirements and ensure the stability of the power system.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The two central goals of this master's thesis are to serve as a guidebook on the determination of uncertainty in efficiency measurements and to investigate sources of uncertainty in efficiency measurements in the field of electric drives by a literature review, mathematical modeling and experimental means. The influence of individual sources of uncertainty on the total instrumental uncertainty is investigated with the help of mathematical models derived for a balance and a direct air cooled calorimeter. The losses of a frequency converter and an induction motor are measured with the input-output method and a balance calorimeter at 50 and 100 % loads. A software linking features of Matlab and Excel is created to process measurement data, calculate uncertainties and to calculate and visualize results. The uncertainties are combined with both the worst case and the realistic perturbation method and distributions of uncertainty by source are shown based on experimental results. A comparison of the calculated uncertainties suggests that the balance calorimeter determines losses more accurately than the input-output method with a relative RPM uncertainty of 1.46 % compared to 3.78 - 12.74 % respectively with 95 % level of confidence at the 93 % induction motor efficiency or higher. As some principles in uncertainty analysis are open to interpretation the views and decisions of the analyst can have noticeable influence on the uncertainty in the measurement result.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The awareness and concern of our environment together with legislation have set more and more tightening demands for energy efficiency of non-road mobile machinery (NRMM). Integrated electro-hydraulic energy converter (IEHEC) has been developed in Lappeenranta University of Technology (LUT). The elimination of resistance flow, and the recuperation of energy makes it very efficient alternative. The difficulties of IEHEC machine to step to the market has been the requirement of one IEHEC machine per one actuator. The idea is to switch IEHEC between two actuators of log crane using fast on/off valves. The control system architecture is introduced. The system has been simulated in co-simulation using two different software. The simulated responses of pump-controlled system is compared to the responses of the conventional valve-controlled system.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Global energy consumption has been increasing yearly and a big portion of it is used in rotating electrical machineries. It is clear that in these machines energy should be used efficiently. In this dissertation the aim is to improve the design process of high-speed electrical machines especially from the mechanical engineering perspective in order to achieve more reliable and efficient machines. The design process of high-speed machines is challenging due to high demands and several interactions between different engineering disciplines such as mechanical, electrical and energy engineering. A multidisciplinary design flow chart for a specific type of high-speed machine in which computer simulation is utilized is proposed. In addition to utilizing simulation parallel with the design process, two simulation studies are presented. The first is used to find the limits of two ball bearing models. The second is used to study the improvement of machine load capacity in a compressor application to exceed the limits of current machinery. The proposed flow chart and simulation studies show clearly that improvements in the high-speed machinery design process can be achieved. Engineers designing in high-speed machines can utilize the flow chart and simulation results as a guideline during the design phase to achieve more reliable and efficient machines that use energy efficiently in required different operation conditions.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Russia approved ambitious reform plan for the electricity sector in 2001 including privatisation of the country’s huge thermal generation assets. So far the sector had suffered from power shortages, aging infrastructure, substantial electricity losses, and weak productivity and profitability numbers. There was obvious need for foreign investments and technologies. The reform was rather successful; the generation assets were privatised in auctions in 2007-2008 and three European energy companies, E.On, Enel and Fortum, invested in and obtained together over 10% of the Russian production assets. The novelty of these foreign investments serves unique object for the study. The political risk is involved in the FDI due to the industry’s social and economic importance. The research’s objective was to identify and analyse the political risk that foreign investors face in the Russian electricity sector. The research had qualitative study method and the empirical data was collected by interviewing. The research’s theoretical framework was based on the existing political risk theories and it focused to understand the Russian government in relation to the country’s stability and define both macro-level and micro-level sources of political risk for the foreign direct investments in the sector. The research concludes that the centralised and obscure political decision-making, economic constriction, high level of governmental control in economy and corruption form the country’s internal macro-level risk sources for the foreign investors in the sector. Additionally the retribution due to the companies’ home country actions, possible violent confrontations at the Russian borders and the currency instability are externally originated risk sources. In the electricity industry there is risk of tightened governmental control and increased regulation and taxation. Similarly the company-level risk sources link to the unreformed heating sector, bargaining with the authorities, diplomatic stress between host and home countries and to companies and government’s divergent perspective for the profit-making. The research stresses the foreign companies’ ability to cope with the characteristics of Russian political environment. In addition to frequent political and market risk assessment, the companies need to focus on currency protection against rouble’s rate fluctuation and actively build good company-citizenship in the country. Good relationship is needed with the Russian political authorities. The political risk identification and the research’s conclusive framework also enable political risk study assessments for other industries in Russia

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Tässä diplomityössä tarkasteltiin Nissan Leaf -sähköauton käytetyn litiumakun soveltuvuutta UPS-varavirtalaitteen energialähteeksi. Kun akku on heikentynyt niin ettei sen kapasiteetti enää ole riittävä autokäyttöön, sitä voidaan kuitenkin vielä hyödyntää muissa sovelluksissa, kuten UPS-laitteessa. Työ sai alkunsa osana GreenDataNet-projektia, jossa pyritään kehittämään datakeskuksiin ympäristöä vähemmän kuormittavia ratkaisuja käyttämällä uusiutuvia energialähteitä, akkujen uusiokäytöllä, sekä energianhallinnan optimoinnilla. Työssä käytiin läpi akun ja sen ohjausjärjestelmän ominaisuuksia, kerrottiin UPS:in ohjelmistoon tehdyistä muutoksista sekä esitettiin testitulokset. Lopputuloksena todettiin akun sopivan muuten hyvin UPS-käyttöön, mutta vaadittu päivittäinen kennojännitteiden tasaus ja sen aiheuttama katkos energian saatavuuteen heikentää UPSin käyttövarmuutta kuorman suojauksessa. Lopussa esitettiin muutamia ehdotuksia tämän ongelman korjaamiseksi.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The Welland Power and Supply Canal Company Limited, established in 1893 and incorporated in 1894 with a capital stock of $500,000. The aim of the company was to harness the natural water supply of the Niagara and Welland Rivers. In 1898 the Canadian Electrical News published a report by Henry Symons, QC outlining the main project of the company. This project involves the construction of a canal from the Welland River to the brow of the mountain at Thorold, a distance of 8 miles; the construction at Thorold of a power house, and from Thorold to Lake Ontario, a raceway by which to carry water into the lake. The estimate for the machinery to generate 100,000 horse power is £125,000; for transmission line to Toronto at a voltage of 10,000….The total estimate therefore amounts to £2,452,162, or roughly speaking, $12,000,000. Source: Canadian Electrical News, August 1898, p. 172. In 1899 the company officers petitioned the federal government desiring a name change to the Niagara-Welland Power Company Limited. Officers of the company were Harry Symons, President; Charles A. Hesson, Vice-President; and M.R. O’Loughlin, James B. Sheehan, James S. Haydon, Frederick K. Foster, directors; John S. Campbell, secretary-treasurer. The company’s head offices were located in St. Catharines, with a New York (City) office on Broad Street. In 1905 and 1909 the company petitioned the federal government for additional time to construct its works, which was granted. The company had until May 16, 1915 to complete construction. John S. Campbell (1860-1950) was a graduate of the University of Toronto and Osgoode Hall. During his university years John began his military career first in "K" Company, Queens Own rifles and then later as Commanding Officer of the 19th Lincoln Regiment, from 1906 to 1910. Upon his return to St. Catharines John Campbell served as secretary in the St. Catharines Garrison Club, a social club for military men begun in 1899. After being called to the Bar, he became a partner in the firm of Campbell and McCarron and was appointed to the bench in 1916, serving until retirement in 1934. Judge Campbell served as an alderman for several terms and was the mayor of St. Catharines in 1908 and 1909. He also served as the first chairman of the St. Catharines Public Utilities in 1914. John S. Campbell was married to Elizabeth Oille, daughter of Jerome B. and Charlotte (St. John) Oille. The family home "Cruachan" was located at 32 Church St.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Walter D’Arcy Ryan was born in 1870 in Kentville, Nova Scotia. He became the chief of the department of illumination at the General Electric Company of Schenectady, New York. He was a founder in the field of electrical illumination. He built the electric steam scintillator which had numerous nozzles and valves. The operator would release steam through the valves. The nozzles all had names which included: Niagara, fan, snake, plume, column, pinwheel and sunburst. The steam scintillator was combined with projectors, prismatic reflectors, flashers and filters to produce the desired effects. In 1920 a group of businessmen from Niagara Falls, New York formed a group who called themselves the “generators’. They lobbied the American and Canadian governments to improve the illumination of the Falls. They were able to raise $58, 000 for the purchase and installation of 24 arc lights to illuminate the Falls. On February 24th, 1925 the Niagara Falls Illumination Board was formed. Initially, the board had a budget of $28,000 for management, operation and maintenance of the lights. The power was supplied free by the Ontario Power Company. They had 24 lights installed in a row on the Ontario Power Company surge tank which was next to the Refectory in Victoria Park on the Canadian side. The official opening ceremony took place on June 8th, 1925 and included a light parade in Niagara Falls, New York and an international ceremony held in the middle of the Upper Steel Arch Bridge. Walter D’Arcy Ryan was the illuminating engineer and A.D. Dickerson who was his New York field assistant directed the scintillator. with information from American Technological Sublime by David E. Nye and the Niagara Falls info website Location: Brock University Archives Source Information: Subject Headings: Added Entries: 100 Ryan, W. D’A. |q (Walter D’Arcy), |d 1870-1934 610 General Electric Company 650 Lighting, Architectural and decorative 650 Lighting |z New York (State) |z Niagara Falls 700 Dickerson, A.F. 700 Schaffer, J.W. Related material held at other repositories: The Niagara Falls Museum in Niagara Falls, Ontario has a program (pamphlet) dedicating new lighting in 1958 and it has postcards depicting the illumination of the Falls. Some of Ryan’s accomplishments can be seen at The Virtual Museum of the City of San Francisco. Described by: Anne Adams Date: Sept 26,Upper Steel Arch Bridge. Walter D’Arcy Ryan was the illuminating engineer and A.D. Dickerson who was his New York field assistant directed the scintillator. with information from American Technological Sublime by David E. Nye and the Niagara Falls info website

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Sir Adam Beck ( a London, Ontario manufacturer, Mayor and Conservative member of the provincial legislature) was a champion of municipal and provincial power ownership. Beck become the “Power Minister” and chairman of the Hydro-Electric Power Commission of Ontario which was the world’s first publicly owned utility. In 1925 the first unit of the Hydro Electric Power Commission’s Queenston Chippawa hydro-electric development on the Niagara River went into service. The station was renamed in 1950 as “Sir Adam Beck #1”. This marked the 25th anniversary of Beck’s death. This is one of 2 generating stations in Niagara Falls. There is also Adam Beck Plant #2. The Niagara generating stations supply one quarter of all power used in New York State and Ontario.Ontario Hydro has two water tunnels which traverse the entire City of Niagara Falls from the Village of Chippawa in the South to the Sir Adam Beck Hydro Electric Generating Stations in the North. Also they are in the process of building the third tunnel. In addition, Ontario Hydro has a 13.6 km open canal which traverses the entire City of Niagara Falls. Source: http://www.hydroone.com/OurCompany/Pages/OurHistory.aspx

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A letter from 2nd Vice President and General Manager of Canadian General Electric Company, Frederic Nicholls to W. B. Rankine regarding a bid for contract. The letter mentions that the bid for two alternating generators for the Canadian side of Niagara Falls was won by Westinghouse Eletric and Manufacturing Co. Nicholls also mentions that there will be other opportunites to win contracts as more machines are required. Nicholls also implies that Westinghouse may have bid under cost in an effort to secure the first of many contracts with the Canadian Niagara Power Company.