This paper analyzes the power flow solution in bipolar direct current networks with radial structures considering multiple monopolar and bipolar constant power loads. The electrical configuration of the bipolar DC grid considers that the reference pole is non-grounded along the feeder, which produces important neutral currents and voltage imbalances along the DC grid. The power flow problem is formulated through the triangular-based representation of the grid topology, which generates a recursive formulation that allows determining the voltage values in the demand nodes through an iterative procedure. The linear convergence of the triangular-based power flow method is tested through multiple load variations with respect to the nominal grid operative condition. Numerical results in the 21- and the 85-bus grids reveal the relevant variations in the voltage profiles and total grid power losses when the neutral cable is solidly grounded or not.
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http://dx.doi.org/10.3390/s22082914 | DOI Listing |
Ultrasound Med Biol
January 2025
Department of Electrical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan.
Objective: Conventional coherent plane wave compounding (CPWC) and sum-of-square power Doppler (PD) estimation lead to low contrast and high noise level in ultrafast PD imaging when the number of plane-wave angle and the ensemble length is limited. The coherence-based PD estimation using temporal-multiply-and-sum (TMAS) of high-lag autocorrelation can effectively suppress the uncorrelated noises but at the cost of signal power due to the blood flow decorrelation.
Methods: In this study, the TMAS PD estimation is incorporated with complementary subset transmit in nonlinear compounding (DMAS-CST) to leverage the signal coherence in both angular and temporal dimensions for improvement of PD image quality.
Med Sci Sports Exerc
November 2024
Department of Biomedical Sciences for Health, Università degli Studi di Milano, ITALY.
Purpose: Cigarette smoking (CS) induces systemic changes that impair cardiorespiratory and muscular function both at rest and during exercise. Although these abnormalities are reported in sedentary, middle-aged smokers (SM) with pulmonary disease, few and controversial studies focused on young, physically active SM at the early stage of smoking history. This study aimed at assessing the impact CS on cardiorespiratory and metabolic response during an incremental test and the subsequent recovery in young, physically active SM without known lung or cardiovascular disease.
View Article and Find Full Text PDFSci Rep
January 2025
Computational Fluid Dynamics Laboratory, School of Mechanical Engineering, VIT, Vellore, 632014, India.
Stenosis causes the narrowing of arteries due to plaque buildup, which impedes blood flow and affects flow dynamics. This work numerically analyzes flow fluctuations in stenosed arteries under realistic physiological conditions (resting and exercise) and external body acceleration. The artery is inclined at angle , and blood rheology is modeled using a generalized power-law fluid.
View Article and Find Full Text PDFZhongguo Zhong Yao Za Zhi
December 2024
Key Laboratory of Modern Preparation of TCM, Ministry of Education, Jiangxi University of Chinese Medicine Nanchang 330004, China.
Identification of critical material attributes(CMAs) is a key issue in the quality control of large-scale TCM products like Jianwei Xiaoshi Tablets. This study focuses on the granules of Jianwei Xiaoshi Tablets, using tablet tensile strength as the primary quality attribute. A method for identifying the CMAs and a design space for the granules were established, along with a predictive model for the granule CMAs based on Fourier transform near-infrared spectroscopy(FT-NIR).
View Article and Find Full Text PDFJ Environ Radioact
January 2025
Institute of Nature and Environmental Technology, Kanazawa University, Kakuma, 920-1192, Kanazawa, Ishikawa, Japan.
Radionuclides, including I, were released into the atmosphere by the Fukushima nuclear power plant accident. We measured the dissolved I concentration in 11 rivers in eastern Fukushima from 2016 to 2020 to clarify the I concentration level in river water under base-flow conditions. During the study period, the maximum I concentration in the river water was 1.
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