1,427 results match your criteria: "Technical University of Ostrava[Affiliation]"

Multichannel ballistocardiography: A comparative analysis of heartbeat detection across different body locations.

PLoS One

August 2024

Department of Cybernetics and Biomedical Engineering, Faculty of Electrical Engineering and Computer Science, VSB-Technical University of Ostrava, Ostrava, Czechia.

The paper presents a validation of novel multichannel ballistocardiography (BCG) measuring system, enabling heartbeat detection from information about movements during myocardial contraction and dilatation of arteries due to blood expulsion. The proposed methology includes novel sensory system and signal processing procedure based on Wavelet transform and Hilbert transform. Because there are no existing recommendations for BCG sensor placement, the study focuses on investigation of BCG signal quality measured from eight different locations within the subject's body.

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Article Synopsis
  • The paper explores how to economically optimize the preparation of ferrite powder for manufacturing hard ferrite magnets by tweaking the feedstock and calcination temperature.
  • Granulates were heated in the 1100-1300 °C range and then crushed to achieve a specific particle size, with the final product showing various particle shapes and sizes confirmed through electron microscopy.
  • The best magnetic performance occurred at 1300 °C, with notable findings on the effects of strontium and barium on magnetic properties, and improvements were possible by further reducing particle size for barium-based ferrites.
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When software systems are introduced, they are typically deployed in field environments similar to those used during development and testing. However, these systems may also be used in various other locations with different environmental conditions, making it challenging to improve software reliability. Factors such as the specific operating environment and the location of bugs in the code contribute to this difficulty.

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Sustainability assessment of machining Al 6061-T6 using Taguchi-grey relation integrated approach.

Heliyon

July 2024

Department of Machining, Assembly and Engineering Metrology, Mechanical Engineering Faculty, VŠB-Technical University of Ostrava, 17, Listopadu 2172/15, Ostrava 708 00, Czech Republic.

Modern machining requires reduction in energy usage, surface roughness, and burr width to produce finished or near-finished parts. To ensure high surface quality in machining processes, it is crucial to minimize surface finish and minimize burr width, which are considered as significant parameters as specific cutting energy. The objective of this study was to identify the optimal machining parameters for milling in order to minimize surface roughness, burr width, and specific cutting energy.

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Our previous studies have shown physiological and yield intensification of selected crops with the application of nanoparticles (NPs). However, the impact on the quantitative, qualitative, and yield parameters of maize ( L.) in field conditions remains highly debated.

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Investigation on the Correlation between Mechanical Strength, Grain Size, and Density of Fly Ash Microspheres in the Context of Refining Process.

Materials (Basel)

July 2024

Institute of Clean Technologies for Extraction and Utilization of Energy Resources, Technical University of Ostrava, 17. listopadu 2172/15, 708 00 Ostrava, Czech Republic.

Fly ash microspheres, also called cenospheres, have many valuable properties that allow them to be widely used. Some of its most important properties are its mechanical and thermal strength as well as its chemical stability. These features constitute an important commercial parameter.

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Harnessing photocatalytic activity of mesoporous graphitic carbon nitride decorated by copper single-atom catalysts for oxidative dehydrogenation of N-heterocycles.

J Colloid Interface Sci

December 2024

Department of Industrial and Engineering Chemistry, Institute of Chemical Technology, Jalna, Maharashtra 431203, India; Nanotechnology Centre, Centre for Energy and Environmental Technologies, VˇSB-Technical University of Ostrava, 17. Listopadu 2172/15, 708 00 Ostrava-Poruba, Czech Republic. Electronic address:

This work describes the application of Cu single-atom catalysts (SACs) for photocatalytic oxidative dehydrogenation of N-heterocyclic amines to the respective N-heteroaromatics through environmentally benign and sustainable pathways. The mesoporous graphitic carbon nitride (mpg-CN), prepared by the one-step pyrolysis method, possesses a lightweight material with a high surface area (95 m g) and an average pore diameter (3.6 nm).

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Single Atom Engineering for Nanorobotics.

ACS Nano

July 2024

Future Energy and Innovation Laboratory, Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 61200 Brno, Czech Republic.

Article Synopsis
  • The field of single atom engineering is a cutting-edge area in nanotechnology, focusing on manipulating individual atoms to create precise materials and devices.
  • Nanorobots (or nanobots) are tiny robotic systems designed to perform tasks at the nanoscale, enabling highly precise interactions with materials.
  • Integrating single atom engineering with nanorobotics allows for the development of advanced, multifunctional devices that can operate at an incredibly small scale, enhancing their capabilities and applications.
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Retinal Image Dataset of Infants and Retinopathy of Prematurity.

Sci Data

July 2024

VSB-Technical University of Ostrava, Faculty of Electrical Engineering and Computer Science, Department of Computer Science, Ostrava, 708 00, Czech Republic.

Article Synopsis
  • Retinopathy of prematurity (ROP) is a sight-threatening condition affecting mainly premature infants, still a major cause of childhood blindness globally despite advances in care.
  • This research presents a comprehensive dataset of 6,004 retinal images from 188 newborns, with details from ROP screenings in the Czech Republic, utilizing three different imaging camera systems.
  • The study introduces an automated software tool, ReLeSeT, for segmenting retinal lesions and enhancing features in retinal images, along with pre-processing tools to improve classification and segmentation models for ROP analysis.
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In this study, we focus on the large-scale ex situ Raman mapping of LiMnO (LMO) electrodes maintained at varying states of charge. A comprehensive statistical analysis has been conducted at an area of ca. 3660 μm on more than 3100 collected spectra for each LMO electrode sample.

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Many-objective optimization (MaO) is an important aspect of engineering scenarios. In many-objective optimization algorithms (MaOAs), a key challenge is to strike a balance between diversity and convergence. MaOAs employs various tactics to either enhance selection pressure for better convergence and/or implements additional measures for sustaining diversity.

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The current study explores the (2+1)-dimensional Chaffee-Infante equation, which holds significant importance in theoretical physics renowned reaction-diffusion equation with widespread applications across multiple disciplines, for example, ion-acoustic waves in optical fibres, fluid dynamics, electromagnetic wave fields, high-energy physics, coastal engineering, fluid mechanics, plasma physics, and various other fields. Furthermore, the Chaffee-Infante equation serves as a model that elucidates the physical processes of mass transport and particle diffusion. We employ an innovative new extended direct algebraic method to enhance the accuracy of the derived exact travelling wave solutions.

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Mixed double helices formed by RNA and DNA strands, commonly referred to as hybrid duplexes or hybrids, are essential in biological processes like transcription and reverse transcription. They are also important for their applications in CRISPR gene editing and nanotechnology. Yet, despite their significance, the hybrid duplexes have been seldom modeled by atomistic molecular dynamics methodology, and there is no benchmark study systematically assessing the force-field performance.

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Unlabelled: Electrogastrography (EGG) is a non-invasive method with high diagnostic potential for the prevention of gastroenterological pathologies in clinical practice. In this study, a review of the measurement systems, procedures, and methods of analysis used in electrogastrography is presented. A critical review of historical and current literature is conducted, focusing on electrode placement, measurement apparatus, measurement procedures, and time-frequency domain methods of filtration and analysis of the non-invasively measured electrical activity of the stomach.

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Real-world rotordynamic systems exhibit inherent uncertainties in manufacturing tolerances, material properties, and operating conditions. This study presents a Monte Carlo simulation approach using MSC Adams View and Adams Insight to investigate the impact of these uncertainties on the performance of a Laval/Jeffcott rotor model. Key uncertainties in bearing damping, bearing clearance, and mass imbalance were modeled with probabilistic distributions.

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An Investigation into Sheet-Inconel 718 Forming with Flexible and Metal Tools-Simulation and Experiment.

Materials (Basel)

June 2024

Department of Mechanical Technology, Faculty of Mechanical Engineering, VSB-Technical University of Ostrava, 17. Listopadu 2172/15, 708 00 Ostrava, Czech Republic.

The article presents the results of numerical simulations and experimental tests of plastic forming sheets made from the difficult-to-deform nickel alloy Inconel 718 with a thickness of 1 mm, using punches made from elastomeric materials with hardness 50-90 Shore A and steel dies. Elastomeric stamps were created in the form of five layers with a diameter of 160 mm. The influence of the hardness of the elastomeric punches on the geometry of the elements obtained was determined.

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Mass Transport Limitations in Plasmonic Photocatalysis.

Nano Lett

July 2024

Czech Advanced Technology and Research Institute, Regional Centre of Advanced Technologies and Materials Department, Palacký University Olomouc, Šlechtitelů 27, Olomouc 78371, Czech Republic.

The interpretation of mechanisms governing hot carrier reactivity on metallic nanostructures is critical, yet elusive, for advancing plasmonic photocatalysis. In this work, we explored the influence of the diffusion of molecules on the hot carrier extraction rate at the solid-liquid interface, which is of fundamental interest for increasing the efficiency of photodevices. Through a spatially defined scanning photoelectrochemical microscopy investigation, we identified a diffusion-controlled regime hindering the plasmon-driven photochemical activity of metallic nanostructures.

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Article Synopsis
  • Microgrids and energy communities are being increasingly utilized, but rural areas face challenges due to lack of information infrastructure, causing operational blind spots in distribution networks.
  • A backward neural network (BNN) is proposed as a control method in multi-feeder microgrid systems to improve load sharing and voltage management, adapting to communication issues that typically affect traditional control.
  • The BNN approach demonstrates greater effectiveness than conventional methods by optimizing load distribution and maintaining voltage stability, particularly under conditions of communication failure.
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Influence of the chemical composition of leachates on the results of ecotoxicity tests for different slag types.

J Environ Manage

August 2024

Material and Metallurgical Research Ltd., Pohraniční 693/31, Vítkovice, 703 00 Ostrava, Czech Republic.

Article Synopsis
  • The study evaluated the ecotoxicological effects of leachates from three types of slag (ladle, blast furnace, and converter) using tests on bacteria, plants, and invertebrates.
  • Results showed that the leachates were non-toxic to Vibrio fischeri and white mustard, with blast furnace slag also showing compliance in tests with Daphnia magna.
  • Characterization of the slags indicated that factors like grain size and the presence of certain ions influence toxicity, but overall, the slags are safe for reuse and compliant with environmental regulations.
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The use of plug-in hybrid electric vehicles (PHEVs) provides a way to address energy and environmental issues. Integrating a large number of PHEVs with advanced control and storage capabilities can enhance the flexibility of the distribution grid. This study proposes an innovative energy management strategy (EMS) using an Iterative map-based self-adaptive crystal structure algorithm (SaCryStAl) specifically designed for microgrids with renewable energy sources (RESs) and PHEVs.

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Single Atom Catalysts Based on Earth-Abundant Metals for Energy-Related Applications.

Chem Rev

November 2024

Regional Centre of Advanced Technologies and Materials, Czech Advanced Technology and Research Institute, Palacký University, Křížkovského 511/8, 779 00 Olomouc, Czech Republic.

Article Synopsis
  • Growing energy consumption driven by population growth and technological advancement is making the use of rare metals in energy processes costly and geopolitically complicated.
  • Earth-abundant single-atom catalysts (SACs) present a promising alternative for electrochemical energy storage and conversion, especially in creating clean fuels and chemicals.
  • The review highlights key processes like oxygen reduction reactions, electrochemical water splitting for hydrogen fuel, and ammonia production through nitrogen reduction, emphasizing the advantages of using transition metal SACs.
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Background: Adipose tissue is significantly involved in inflammatory bowel disease (IBD). Vitamin D can affect both adipogenesis and inflammation. The aim of this study was to compare the production of selected adipokines, potentially involved in the pathogenesis of IBD - adiponectin, resistin, retinol binding protein 4 (RBP-4), adipocyte fatty acid binding protein and nesfatin-1 in children with IBD according to the presence of 25-hydroxyvitamin D (25(OH)D) deficiency.

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This research examines pseudoparabolic nonlinear Oskolkov-Benjamin-Bona-Mahony-Burgers (OBBMB) equation, widely applicable in fields like optical fiber, soil consolidation, thermodynamics, nonlinear networks, wave propagation, and fluid flow in rock discontinuities. Wave transformation and the generalized Kudryashov method is utilized to derive ordinary differential equations (ODE) and obtain analytical solutions, including bright, anti-kink, dark, and kink solitons. The system of ODE, has been then examined by means of bifurcation analysis at the equilibrium points taking parameter variation into account.

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Load frequency control (LFC) plays a critical role in ensuring the reliable and stable operation of power plants and maintaining a quality power supply to consumers. In control engineering, an oscillatory behavior exhibited by a system in response to control actions is referred to as "Porpoising". This article focused on investigating the causes of the porpoising phenomenon in the context of LFC.

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Software-defined networking (SDN) is a pioneering network paradigm that strategically decouples the control plane from the data and management planes, thereby streamlining network administration. SDN's centralized network management makes configuring access control list (ACL) policies easier, which is important as these policies frequently change due to network application needs and topology modifications. Consequently, this action may trigger modifications at the SDN controller.

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