2,638 research outputs found
Optimisation of Magnetic Circuit for Brushless Doubly Fed Machines
This paper presents an optimized design method for the magnetic circuit of brushless doubly fed machines (BDFMs). The BDFM is an attractive electrical machine, particularly for wind power applications, as a replacement for doubly fed slip-ring generators. This study shows that the conventional design methods for the BDFM stator and rotor back iron can be modified, leading to a lighter and smaller machine. The proposed design concepts are supported by analytical methods, and their practicality is verified using two-dimensional finite-element modeling and analysis. Two BDFMs with frame sizes D180 and D400 are considered in this study
Equivalent Circuit Parameters for Large Brushless Doubly Fed Machines (BDFM)
This paper presents analytical methods to calculate the equivalent circuit parameters for large-scale brushless doubly fed machines (BDFMs) with magnetic wedges utilized for closing stator open slots. The use of magnetic wedges reduces the magnetizing currents in the machine, reflected in the values of magnetizing inductances, but also increases leakage fluxes affecting the value of series inductances in the equivalent circuit. Though such effects can be modeled by numerical models, the proposed analytical methods are particularly helpful in optimizing machine design, inverter rating, reactive power management, and grid low-voltage ride-through performance. The conventional analytical methods cannot be readily applied to the BDFM due to its complex magnetic field distribution; this paper presents analytical methods to calculate the magnetizing and leakage inductances for the BDFM with magnetic wedges used in the stator slots. The proposed methods are assessed by experimentally verified finite-element models for a 250 kW BDFM
Rotor parameter determination for the brushless doubly fed (induction) machine
A procedure has been established for obtaining equivalent circuit parameters for the Brushless Doubly Fed Machine (BDFM),
also known as the Brushless Doubly Fed Induction Machine (DFIM), by transforming a reduced coupled-circuit model into a
sequence component form. This approach takes advantage of the model reduction procedure’s ability to reduce a complex rotor
structure to a single equivalent loop without significant loss of accuracy. An alternative method based on winding factors has
also been developed and includes coupling via harmonic fields. Parameters determined in both ways are in close agreement with
those determined from Finite Element Analysis (FEA) and experimentally. The advantages of each method is discussed in the
conclusion section.This work was supported by the European Union's Seventh Framework Programme managed by REA – Research Executive Agency (FP7/2007_2013) under Grant Agreement N.315485.This is the author accepted manuscript. The final version is available from IEEE via http://dx.doi.org/10.1049/iet-epa.2015.002
Effect of different salinity concentration on kidney of benni, Barbus sharpeyi
For this study, 144 healthy Barbus sharpeyi with an average weight of 350 ± 2.36 grams and length 25 ± 1.25 cm in five groups were studied. The first group as control located in municipal dechlorination water and the next four groups respectively were kept in salinity 4ppt, 8ppt, 12ppt and 16ppt in the same condition. On days 1 , 3 , 7 , 14 , 21 and 28 sample of kidney with maximum thickness of 0.5 cm prepare and were placed in bouin's solution.Then the standard method of parafin sections were done and 5- 6 micrometer thick of tissue sections prepared and stained with H&E methods. Results showed the gradual transfer of fish to water with high salinity caused obvious changes as increase the number and diameter of the glomeruli especially in high salinity but the severity was reduced at the end of the period (p<0.05). Also highest diameter and thickness of the collecting tubules were reported in fresh water at 28 days (p<0.05). These findings suggest that fish Barbus sharpeyi was friendly with salinity and ability to set vital to different salinity
Quantum optomechanics of a multimode system coupled via photothermal and radiation pressure force
We provide a full quantum description of the optomechanical system formed by
a Fabry-Perot cavity with a movable micro-mechanical mirror whose
center-of-mass and internal elastic modes are coupled to the driven cavity mode
by both radiation pressure and photothermal force. Adopting a quantum Langevin
description, we investigate simultaneous cooling of the micromirror elastic and
center-of-mass modes, and also the entanglement properties of the
optomechanical multipartite system in its steady state.Comment: 11 pages, 7 figure
Effect of Achillea millefolium Distillate on Recovery Time in Patients with Gastroenteritis
Background: Some animal studies have reported that Achillea millefolium (A. millefolium) extract can affect intestinal movements in rats. However, no study is available on the effect of A. millefolium on recovery from gastroenteritis in human subjects.
Objectives: This study aimed to investigate the effect of A. millefolium on recovery from gastroenteritis in patients over 12 years old.
Patients and Methods: A randomized controlled trial was conducted on 44 patients with gastroenteritis. The patients were randomly assigned to two groups of 22 each. The control group received the usual treatments. In addition to the usual treatments, the intervention group received 0.5 mL/kg of A. millefolium distillate every 8 hours. The duration of recovery was recorded for both groups. Descriptive statistics, Chi-square, Fisher’s exact test, and the t-test were used to compare the two groups.
Results: The mean duration of recovery in the group receiving A. millefolium distillate was 1.31 ± 0.71 days, while it was 1.86 ± 0.71 days in the control group (P = 0.015).
Conclusions: Adding A. millefolium distillate to the usual treatment for simple gastroenteritis was effective in shortening the recovery time
Histological study of liver and pancreas in adult Otolithes ruber in Bushehr, Iran
In this study, the digestive systems of 10 adult Otolithes ruber specimens from Bushehr province water, south-west Iran were removed and the livers and pancreases were fixed in formalin 10%. The routine procedures of preparation of tissues were followed and the paraffin blocks were cut at 6 microns, stained with H&E and studied under light microscope. The results of microscopic studies showed that liver as the largest accessory organ surrounds the pancreatic tissue in the fish. Liver was found to be a lobulated organ encircling the pancreas among its lobules. Hepatic tissue of the fish was found to be similar to many other bony fishes. Hepatocytes included glycogen and fat vacuoles that located around the hepatic sinusoids. Pancreas as a mixed gland microscopically, was composed of lobules consisting of serous acini (exocrine portion) and langerhans islets (endocrine portion). Pancreatic lobules are usually found as two rows of acini which a large blood vessel located in between
Marketing authorization procedures for advanced cancer drugs: exploring the views of patients, oncologists, healthcare decision makers and citizens in France
International audienceBackground. The past decades have seen advances in cancer treatments in terms of toxicity and side effects but progress in the treatment of advanced cancer has been modest. New drugs have emerged improving progression free survival but with little impact on overall survival, raising questions about the criteria on which to base decisions to grant marketing authorizations and about the authorization procedure itself. For decisions to be fair, transparent and accountable, it is necessary to consider the views of those with relevant expertise and experience. Methods. We conducted a Q-study to explore the views of a range of stakeholders in France, involving: 54 patients (18 months after diagnosis); 50 members of the general population; 27 oncologists; 19 healthcare decision makers; and 2 individuals from the pharmaceutical industry. Results. Three viewpoints emerged, focussing on different dimensions entitled: 1) ‘Quality of life (QoL), opportunity cost and participative democracy’; 2)‘QoL and patient-centeredness’; and 3) ‘Length of life’. Respondents from all groups were associated with each viewpoint, except for healthcare decision makers, who were only associated with the first one. Conclusion. Our results highlight plurality in the views of stakeholders, emphasize the need for transparency in decision making processes, and illustrate the importance of a re-evaluation of treatments for all 3 viewpoints. In the context of advanced cancer, our results suggest that QoL should be more prominent amongst authorization criteria, as it is a concern for 2 of the 3 viewpoints
Energy Efficiency in Buildings and Excess Summer Mortality in the UK
One of the main objective of the building design is to provide comfort and safety to occupants, particularly during adverse weather conditions. In most part of the world, people stay indoors during adverse weather conditions, thus increasing energy consumption. In UK, vulnerable people such as the elderly are highly affected with mortality rate during extreme weather conditions. The 2003 heatwave reached average of 38.5° C in the UK resulting in the death toll of 2,234. The 10 days period of extreme heat is thought to be the warmest about the last 500 years. Across Europe, the 2003 heatwave resulted in 20,000 deaths; in France alone, the number reached 15,000. Similarly, the 2018 summer heatwaves, reached 35.5°C contributing to 863 deaths. Yet, there is little research regarding impact of energy efficiency in building and deaths caused by excessive heatwaves in the UK. The study aims to investigate the impact of energy efficiency in buildings and excessive heatwave deaths among elderly people in the UK. Research question asked is; do energy efficiency programmes and policies contribute to excessive summer deaths in the UK? .The study adopted quantitative research method with participants drawn from low/average income households, in west midlands part of UK, between 2003/04 to 2017/18. Initial findings show that there is a significant relationship between energy efficiency adoption, government policies and excessive summer deaths
The Impact of Brand Image and Marketing Mix on Buying Decision for Toyota Calya
Toyota Calya is one of Toyota’s product which succeed in achieving high sales volume based on GAIKINDO’s data. Toyota Calya sold around 68.038 unit for the year 2017 only. This fantastic sales volume record was indicated to be influenced by the strong brand image of Toyota in the mind of Indonesian consumers and the core elements which built Toyota Calya as a solid offering, includes product, price, place, and promotion. This research is designed to identify the impact of brand image and marketing mix variable on Toyota Calya’s buying decision. This quantitative research is conducted on 60 selected responders based on purposive sampling method. The method of analysis used in this research is multiple linear regression. The data analysis result shows that there is significant evidence to conclude that brand image and marketing mix variable has positive impact on Toyota Calya’s buiying decision. The well known Toyota brand and the easiness to gather relevan information about the product considered as strong contributor on Toyota Calya buying decision
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