890 research outputs found

    Development and experimental validation of a low-frequency dynamic model for a Hybrid Electric Vehicle

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    This paper describes the development and experimental validation of a high-fidelity Hybrid Electric Vehicle (HEV) simulator that enables testing and calibration of energy management and driveline control strategies. The model is capable of predicting longitudinal vehicle responses that affect energy consumption and drivability in the low-to-mid frequency region (up to 10 Hz). The simulator focuses primarily on the drivetrain dynamics, while the dynamics of the actuators are represented by simplified models. The vehicle simulator is validated by a number of experiments that include electric only, engine only and hybrid operating conditions. The test vehicle has a through-the-road parallel hybrid architecture that utilises a dual electric machine configuration. Experimental results confirm that important driveline phenomena such as shunt, shuffle, torque holes and other transient disturbances related to operating mode changes are accurately predicte

    Insight into the HEV/PHEV optimal control solution based on a new tuning method

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    The paper presents a formulation of the energy management problem for Hybrid Electrical Vehicles and Plug-in Hybrid Electrical Vehicles alike, which permits to consider different cost indexes like fuel consumption, total and primary energy consumption, economic cost or CO2 footprint. In-depth analysis of the problem optimal solution is done by means of the application of the λ-plot method, which also permits the optimal tuning of other implementable control strategies. Such an approach is used to understand the effect of the selected cost index, the regional energetic share, the driving conditions, and for deriving rules for battery sizing.C. Guardiola and B. Pla research has been partially supported by Ministerio de Ciencia e Innovacion through Project TRA2010-16205 uDiesel, and the Universitat Politecnica de Valencia through Grants PAID-00-11 2105 and PAID-00-11 2106.Guardiola García, C.; Plá Moreno, B.; Onori, S.; Rizzoni, G. (2014). Insight into the HEV/PHEV optimal control solution based on a new tuning method. Control Engineering Practice. 29:247-256. https://doi.org/10.1016/j.conengprac.2014.01.022S2472562

    Repositório de acesso livre para agroecologia e agricultura orgânica do Brasil.

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    Resumo: Considerando que a literatura técnico-científica em Agroecologia e Agricultura Orgânica no Brasil é abundante, está dispersa e de difícil acesso, esse trabalho teve como objetivo criar e gerenciar um banco de dados da literatura no Brasil. Nesse sentido, há consenso na comunidade de especialistas e pesquisadores que estudam a informação, que a alternativa mais adequada e adotada em todo o mundo são os repositórios digitais de acesso aberto. Além de contemplarem os processos necessários para o gerenciamento da informação técnico-científica, os repositórios digitais de acesso aberto contribuem diretamente para a melhoria dos processos de comunicação na Ciência. Assim, o repositório escolhido para armazenar a literatura brasileira em Agroecologia e Agricultura Orgânica foi o Organic Eprints

    Prospective randomized comparison of laparoscopic versus open adrenalectomy for sporadic pheochromocytoma.

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    BACKGROUND: Laparoscopic adrenalectomy for pheochromocytoma remains subject of debate, owing to the systemic consequences of pneumoperitoneum in patients with catecholamine-secreting tumors. METHODS: A prospective randomized study was conducted (2000-2006), evaluating cardiovascular instability during open (n = 9, group A) or laparoscopic (n = 13, group B) adrenalectomy for pheochromocytoma. Haemodynamic parameters were recorded by invasive monitoring. RESULTS: Haemodynamic instability was observed in 3/9 (group A) and 6/13 patients (group B), with a mean of 1.8 and 2.2 hypertensive peaks per patient (p = n.s.). Blood loss (164 +/- 94 cc versus 48 +/- 36 cc, p < 0.05) and operative time (180 +/- 40 versus 158 +/- 45 min, p = n.s.) favored laparoscopic procedures. Postoperative morbidity and mortality were nil. Hospital stay was shorter in group B (p < 0.05). Long-term follow-up was always normal. CONCLUSIONS: Laparoscopic approach for pheochromocytoma can be as safe as open surgery; intraoperative haemodynamic instability, although usually controlled with success, remains a source of concern

    Case Control Study on Dialysis Arthropathy: The Influence of Two Different Dialysis Membranes: Data from the EDTA Registry

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    In a retrospective case control study the prevalence of signs and symptoms of dialysis osteoarthropathy was analysed. Cases and controls had received over 9 years of maintenance haemodialysis uninterrupted by peritoneal dialysis or transplantation. The cases comprised 55 patients treated predominantly with polyacrylonitrile (AN69) dialysers. They were compared to a matched group dialysed exclusively with cellulosic membranes. Over 60% of all patients, cases and controls, showed one or more signs of disabling osteoarthropathy, with joint pains occurring more frequently in the older age groups. Twenty-seven of the 55 cases who had received less than 2 years of cellulosic membrane dialysis followed by 7-12 years of AN69 dialysis tended to have a lower prevalence of joint pains, carpal-tunnel syndrome and bone cysts. However, no statistically significant differences were obtained compared to the matched control group dialysed exclusively on cellulosic membranes (mostly cuprophane). The remaining 28 cases, who had been treated for more than 2 years with cellulosic membranes preceding the longer treatment period with polyacrylonitrile dialysers, showed a prevalence similar to that of their cellulosic controls. This study thus shows little, if any, influence of the two types of membranes on the prevalence of signs and symptoms of β2-microglobulin amyloidosi

    Demography of Dialysis and Transplantation in Children in Europe, 1985: Report from the European Dialysis and Transplant Association Registry

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    At the end of 1985 there were 5482 patients known to the Registry who started renal replacement therapy (RRT) between the ages of 6 months and 15 years. Of these, approximately 25% had died, 30% were still aged less than 15 years, and the other 45% were older. The acceptance rate of new patients over the last 10 years has slowly but steadily increased; six new paediatric patients per million child population probably represents the likely needs of the near future. Hospital haemodialysis remained the main form of renal replacement therapy in new patients, while 3 years after start of RRT, transplantation became the most frequently used replacement therapy; CAPD appeared to be used mainly in children with a short waiting time for transplantation. Out of the 384 grafts reported in 1985, only 16% were from living related donors; among 321 cadaver grafts, 24% were second and only 3% were third grafts. Glomerulonephritis and pyelonephritis accounted for 50% of all primary renal diseases. During the last 5 years, the proportion with glomerulonephritis seems to have decreased slightly. Hyperkalaemia and fluid overload have still to be considered the main causes of death. Only in 17% of all cases was the cause of death reported as unknown or undetermine

    Successful pregnancies in women on renal replacement therapy: Report from the EDTA Registry

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    This study reports the geographical incidence of successful pregnancies in women on renal replacement therapy (RRT) and related information on gestation and clinical status of newborns. The impact of successful pregnancy on graft function was assessed by means of a retrospective case-control study. Since 1977 special questionnaires have been sent to each dialysis and transplant centre which reported babies born to mothers on RRT on the yearly centre questionnaire. After 10 years of data collection, a total of 490 pregnancies and 500 babies were available for analysis. A percentage of 88.4 of the babies were born to mothers with a functioning graft, 11.2% to mothers on chronic haemodialysis, and the remaining 0.4% to mothers on CAPD. Almost 50% of all successful pregnancies werereported from the UK. The number of successful pregnancies increased steadily and in parallel with the increasing number of females of childbearing age with a functioning renal transplant. The majority of mothers delivered at age 24-32. For transplanted mothers delivery occurred most commonly during the 3rd and 4th year after successful transplantation. In approximately 85% of cases the duration of pregnancy was shorter than the lower 10th percentile of normal. Birthweight was reduced in accordance with gestational age. Newborn mortality was 1.8%. Fifty-three mothers with a successful pregnancy in 1984-1987 were computer matched with controls according to a number of criteria. The serum creatinine concentration recorded in coded form at the end of each year on the individual EDTA patient questionnaire was used to assess changes in graft function. In 94% of these cases the serum creatinine, recorded 0-11 months before delivery, did not exceed 160 umol/1. Graft function deteriorated in 18% ofmothers as compared to 24% of controls. Twentyfour to 36 months postpartum, changes of serum creatinine were similar in test cases and controls, suggesting that a successful pregnancy does not adversely affect graft function if this was stable and well preserved at the time of conceptio

    Rehabilitation of young adults during renal replacement therapy in Europe: The presence of disabilities

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    The aim of this study was to analyse rehabilitation during RRT in 617 young adults from different European countries who started dialysis or transplantation before the age of 15 years. The data were derived from the EDTA Registry patient data files and a special questionnaire that was sent to centres reporting to the EDTA Registry. The duration of RRT was more than 10 years in 63% of patients. Fifty-four percent were living with a functioning graft and 46% were on dialysis. The prevalence and severity of motor, hearing, sight, and mental disabilities were analysed retrospectively. They were found to vary according to primary renal disease and method oftreatment. One-third of patients had one or more disabilities at the start of RRT. Although disability status had changed in many patients by 31 December 1986, some disability remained in one-third of the patients available for study. Disabilities were recorded as mild in the majority of patients. Both improvement and worsening of motor and mental disability occurred more often than changes of hearing capacity and sight. It is concluded that prevention and treatment of disabilities need special attention in children and young adults on RRT in order to improve rehabilitatio
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