3,152 research outputs found
A Novel PMSM Hybrid Sensorless Control Strategy for EV Applications Based on PLL and HFI
In this paper, a novel hybrid sensorless control strategy for Permanent Magnet Synchronous Machine (PMSM) drives applied to Electric Vehicles (EV) is presented. This sensorless strategy covers the EV full speed range and also has speed reversal capability. It combines a High Frequency Injection (HFI) technique for low and zero speeds, and a Phase-Locked Loop (PLL) for the medium and high speed regions. A solution to achieve smooth transitions between the PLL and the HFI strategies is also proposed, allowing to correctly detect the rotor position polarity when HFI takes part. Wide speed and torque four-quadrant simulation results are provided, which validate the proposed sensorless strategy for being further implemented in EV.Peer ReviewedPostprint (author's final draft
IPMSM torque control strategies based on LUTs and VCT feedback for robust control under machine parameter variations
In recent years, Interior Permanent Magnet Synchronous
Machines (IPMSMs) have attracted a considerable
attention in the scientific community and industry for Electric
and Hybrid Electric Vehicle (HEV) propulsion systems. Lookup
Table (LUT) based Field Oriented Control (FOC) strategies
are widely used for IPMSM torque control. However, LUTs
strongly depend on machine parameters. Deviations of these
parameters due to machine ageing, temperature or manufacturing
inaccuracies can lead to control instabilities in the field
weakening region. In this paper, two novel hybrid IPMSM
control strategies combining the usage of LUTs and Voltage
Constraint Tracking (VCT) feedbacks are proposed in order to
overcome the aforementioned controllability issues. Simulation
results that demonstrate the validity of the proposed approaches
are presented.Postprint (author's final draft
Perceptual mapping of mulitiple variable batteries by plotting supplementary variables in correspondence analysis of rating data
In this paper we consider the use of correspondence analysis (CA) of rating data. CA of rating data allows a joint representation of the rated items (e.g. attributes or products) and individuals. However, as the number of individuals increases, the interpretation of the CA map becomes difficult. To overcome this problem, we propose a method that allows the depiction of additional variables, for example, background characteristics that may be of interest in identifying consumer segments, in the CA map. The idea we use is based on the representation of supplementary variables in ordinary CA. However, as the format of the additional variables is typically different from the rating data, a recoding is required. We illustrate our new method by means of an application to data of a product perception study for five cream soups
No evidence of family history as a risk factor for herpes zoster in patients with post-herpetic neuralgia
Little is known about reactivation of latent varicella zoster virus as herpes zoster in individuals with no underlying immunosuppression. Risk factors include age, sex, ethnicity, exogenous boosting of immunity from varicella contacts, underlying cell-mediated immune disorders, mechanical trauma, psychological stress, and immunotoxin exposure. An association between herpes zoster and family history of zoster has been proposed. A case-control study involving patients affected by post-herpetic neuralgia, which usually follows more severe acute herpes zoster, was performed. The patients with post-herpetic neuralgia were enrolled at the Pain Clinic of the Policlinico Tor Vergata in Rome, Italy, within 1 year from the onset of acute zoster. The controls matched for sex and age were chosen among healthy subjects without a history of herpes zoster presenting at the Internal Medicine Outpatient Clinic for hypertension in the same time period. All the participants in the study gave informed consent and were interviewed by medically trained and blinded investigators using a questionnaire. Similar proportions of the patients and the controls reported a family history of herpes zoster irrespective of the degree of relationship, i.e., 17.4% and 18.2%, respectively, by analyzing only the first-degree relatives [RR 1.03 (CI 95%: 0.78-1.37)], and 28.4% and 29.6%, respectively, by analyzing the total number of relatives [RR 1.03 (CI 95%: 0.81-1.31)]. Further and larger prospective cohort studies are needed to ascertain whether a family history of herpes zoster is really an independent predictor of zoster in different geographical settings
Cancer of the Thyroid in patients over the age of fifty.
Aim. The authors performed a retrospective investigation of
patients over thè age of 50, in order to detect any peculiarities of
cancer of thè thyroid possibly affecting surgical treatment and
whether age itself represented an independent prognostic factor.
Methods. A total of 152 patients were examined at thè Department
of Surgical Science of "La Sapienza" University of Rome
with a minimum follow- up of 10 years. The 152 subjects recruited
were divided into 3 age groups: from 51 to 60 years, (74 patients);
from 61 to 70 years, (57 patients); from 71 to 80 years, (21 patients).
Resulti. Relating thè different histologic types to age group, there
was found to be a lower incidence of well-differentiated carcinoma
and a relative increase in thè epidermoid and undifferentiated
forms in older patients. In thè 51-60 age group 80% of thè
patients were at stages I and II, while in thè 71-80 age group
56.2% of cases were at stages III and IV.
Conclusion. In thè elderly patient undifferentiated, anaplastic or
epidermoid forms and those with a higher biologica! aggressiveness
are more frequently found. We believe that prompt diagnosis
would present thè surgeon with neoplasms at an early stage
and with less aggressive histotypes, thus ensuring greater scope
for radicai surgical treatment and appreciably enhancing prognosis
Deregulated expression of aurora kinases is not a prognostic biomarker in papillary thyroid cancer patients.
Abstract
A number of reports indicated that Aurora-A or Aurora-B overexpression represented a negative prognostic factor in several human malignancies. In thyroid cancer tissues a deregulated expression of Aurora kinases has been also demonstrated, butno information regarding its possible prognostic role in differentiated thyroid cancer is available. Here, weevaluated Aurora-A and Aurora-B mRNA expression and its prognostic relevance in a series of 87 papillary thyroid cancers (PTC), with a median follow-up of 63 months. The analysis of Aurora-A and Aurora-B mRNA levels in PTC tissues, compared to normal matched tissues, revealed that their expression was either up-or down-regulatedin the majority of cancer tissues. In particular, Aurora-A and Aurora-B mRNA levels were altered, respectively, in 55 (63.2%) and 79 (90.8%) out of the 87 PTC analyzed. A significant positive correlation between Aurora-A and Aurora-B mRNAswas observed (p=0.001). The expression of both Aurora genes was not affected by the BRAF(V600E) mutation. Univariate, multivariate and Kaplan-Mayer analyses documented the lack of association between Aurora-A or Aurora-B expression and clinicopathological parameterssuch as gender, age, tumor size, histology, TNM stage, lymph node metastasis and BRAF status as well asdisease recurrences or disease-free interval. Only Aurora-B mRNA was significantly higher in T(3-4) tissues, with respect to T(1-2) PTC tissues. The data reported here demonstrate that the expression of Aurora kinases is deregulated in the majority of PTC tissues, likely contributing to PTC progression. However, differently from other human solid cancers, detection of Aurora-A or Aurora-B mRNAs is not a prognostic biomarker inPTC patients
Characterization of liposomes coated with S-layer proteins from lactobacilli
The stability of liposomes coated with S-layer proteins from Lactobacillus brevis and Lactobacillus kefir was analyzed as a previous stage to the development of a vaccine vehicle for oral administration. The interactions of the different S-layer proteins with positively charged liposomes prepared with soybean lecithin or dipalmitoylphosphatidylcholine were studied by means of the variation of the Z potential at different protein-lipid ratios, showing that both proteins were able to attach in a greater extent to the surface of soybean lecithin liposomes. The capacity of these particles to retain carboxyfluorescein or calcein by exposure to bile salts, pancreatic extract, pH change and after a thermal shock showed that both S-layer proteins increased the stability of the liposomes in the same magnitude. The non-glycosylated protein from L. brevis protects more efficiently the liposomes at pH 7 than those from L. kefir even without treatment with glutaraldehyde.Centro de Investigación y Desarrollo en CriotecnologÃa de Alimento
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