Research of a bi-directional DC-DC converter integrated in electric car power installation

This article presents the results of the simulation study of the bi-directional DC converter, including the time diagrams of the electric vehicle speed, voltage and current changes in various experiments, Also presented are the results of efficiency change and charge level, when using a bi-directional converter as well as without using it. The HFEDC (Highway Fuel Economy Driving Schedule) model was chosen for the simulation of the electric vehicle drive model using units simulating standardized driving cycles and as an algorithm for changing the vehicle's control signal. Studies of the operating modes of the electrical equipment and the electric vehicle with the DC voltage conversion device in the power circuit of the DC source have been carried out by computer simulation in specialized programs for the study of dynamic systems. The simulation model of the reversible DC converter in the electrical power equipment of an electric vehicle was constructed on the basis of mathematical models of the individual elements reflecting their real physical properties. The present solution is the use of two-way DC voltage converters in the power conversion systems of modern electric drives, including the electric propulsion systems of prospective vehicles improves the efficiency of these systems. © Published under licence by IOP Publishing Ltd

Exposure from the Chernobyl accident had adverse effects on erythrocytes, leukocytes, and, platelets in children in the Narodichesky region, Ukraine: A 6-year follow-up study

<p>Abstract</p> <p>Background</p> <p>After the Chernobyl nuclear accident on April 26, 1986, all children in the contaminated territory of the Narodichesky region, Zhitomir Oblast, Ukraine, were obliged to participate in a yearly medical examination. We present the results from these examinations for the years 1993 to 1998. Since the hematopoietic system is an important target, we investigated the association between residential soil density of ¹³⁷Caesium (¹³⁷Cs) and hemoglobin concentration, and erythrocyte, platelet, and leukocyte counts in 1,251 children, using 4,989 repeated measurements taken from 1993 to 1998.</p> <p>Methods</p> <p>Soil contamination measurements from 38 settlements were used as exposures. Blood counts were conducted using the same auto-analyzer in all investigations for all years. We used linear mixed models to compensate for the repeated measurements of each child over the six year period. We estimated the adjusted means for all markers, controlling for potential confounders.</p> <p>Results</p> <p>Data show a statistically significant reduction in red and white blood cell counts, platelet counts and hemoglobin with increasing residential ¹³⁷Cs soil contamination. Over the six-year observation period, hematologic markers did improve. In children with the higher exposure who were born before the accident, this improvement was more pronounced for platelet counts, and less for red blood cells and hemoglobin. There was no exposure×time interaction for white blood cell counts and not in 702 children who were born after the accident. The initial exposure gradient persisted in this sub-sample of children.</p> <p>Conclusion</p> <p>The study is the first longitudinal analysis from a large cohort of children after the Chernobyl accident. The findings suggest persistent adverse hematological effects associated with residential ¹³⁷Cs exposure.</p

Development of a subsystem for automatic protection of submersible pumps based on mathematical modeling

In this paper, the authors produce a mathematical modelling of a piston pump, develop algorithms for the operation of a protection system, taking into account the results of mathematical modelling. The authors test the mathematical model on the operation of real equipment and analyze its accuracy

Development of a subsystem for automatic protection of submersible pumps based on mathematical modeling

In this paper, the authors produce a mathematical modelling of a piston pump, develop algorithms for the operation of a protection system, taking into account the results of mathematical modelling. The authors test the mathematical model on the operation of real equipment and analyze its accuracy

Adverse cardiac remodeling is absent in patients with true controlled resistant hypertension

Abstract Resistant hypertension (RHTN), defined as blood pressure (BP) that is uncontrolled with ≥3 medications, including a long‐acting thiazide diuretic, also includes a subset with BP that is controlled with ≥4 medications, so‐called controlled RHTN. This resistance is attributed to intravascular volume excess. Patients with RHTN overall have a higher prevalence of left ventricular hypertrophy (LVH) and diastolic dysfunction compared to patients with non‐RHTN. We tested the hypothesis that patients with controlled RHTN due to the intravascular volume excess have higher left ventricular mass index (LVMI), higher prevalence of LVH, larger intracardiac volumes, and more diastolic dysfunction compared to patients with controlled non‐resistant hypertension (CHTN), defined as BP controlled with ≤3 anti‐hypertensive medications. Patients with controlled RHTN (n = 69) or CHTN (n = 63) who were treated at the University of Alabama at Birmingham were offered enrollment and underwent cardiac magnetic resonance imaging. Diastolic function was assessed by peak filling rate, time needed in diastole to recover 80% of stroke volume, E:A ratios and left atrial volume. LVMI was higher in patients with controlled RHTN (64.4 ± 22.5 vs 56.9 ± 11.5; P = .017). Intracardiac volumes were similar in both groups. Diastolic function parameters were not significantly different between groups. There were no significant differences in age, gender, race, body mass index, dyslipidemia between the two groups. The findings show that patients with controlled RHTN have higher LVMI, but comparable diastolic function to those of patients with CHTN