1,322 results match your criteria: "VSB - Technical University of Ostrava[Affiliation]"

Creep Resistance and Microstructure Evolution in P23/P91 Welds.

Materials (Basel)

January 2025

Faculty of Materials Science and Technology, VŠB-Technical University of Ostrava, 17. listopadu 2172/15, 708 00 Ostrava, Czech Republic.

This paper summarizes the results of investigations into heterogeneous P23/P91 welds after long-term creep exposure at temperatures of 500, 550 and 600 °C. Two variants of welds were studied: In Weld A, the filler material corresponded to P91 steel, while in Weld B, the chemical composition of the consumable material matched P23 steel. The creep rupture strength values of Weld A exceeded those of Weld B at all testing temperatures.

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The popularity of 3D printing technology is rapidly increasing worldwide. It can be applied to metals, ceramics, composites, hybrids, and polymers. Three-dimensional printing has the potential to replace conventional manufacturing technologies because it is cost effective and environmentally friendly.

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Higher-end science and technology facilitate the human community with a sophisticated life despite it curses by abundant pollution. The alarming demand for sustainability pressurizes the manufacturing sector to ensure sustainable manufacturing. Since Molybdenum di sulfide (MoS) and avocado oil are known solid and liquid lubricants respectively, hence, it is a worthwhile attempt to implement the bio-based degradable avocado oil enriched with nano Molybdenum di sulfide (nMoS) particles as a potential machining fluid for CNC-end milling.

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In recent times, there has been notable progress in control systems across various industrial domains, necessitating effective management of dynamic systems for optimal functionality. A crucial research focus has emerged in optimizing control parameters to augment controller performance. Among the plethora of optimization algorithms, the mountain gazelle optimizer (MGO) stands out for its capacity to emulate the agile movements and behavioral strategies observed in mountain gazelles.

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Malware is a common word in modern era. Everyone using computer is aware of it. Some users have to face the problem known as Cyber crimes.

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This article presents a laboratory device by which the course of two signals can be detected using two types of sensors-strain gauges and the DEWESoft DS-NET measuring apparatus. The values of the coefficient of friction of the brake lining when moving against the rotating shell of the brake drum were determined from the physical quantities sensed by tensometric sensors and transformed into electrical quantities. The friction coefficient of the brake lining on the circumference of the rotating brake disc shell can be calculated from the known values measured by the sensors, the design dimensions of the brake, and the revolutions of the rotating parts system.

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: Postoperative pneumonia and complications significantly impact outcomes in thoracic surgery, particularly for patients undergoing lobectomy for non-small cell lung cancer (NSCLC). This study evaluates whether preoperative premedication influences the risk of postoperative pneumonia and overall complications. : This retrospective study included 346 patients who underwent lobectomy for NSCLC at the University Hospital Ostrava between 2015 and 2021.

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A critical review of microplastics characterisation in aquatic environments: recent trends in the last 10 years.

Anal Methods

January 2025

CICECO-Aveiro Institute of Materials, Department of Physics, University of Aveiro, Aveiro, 3810-193 Aveiro, Portugal.

Anthropogenic activities have introduced various contaminants into freshwater and marine ecosystems. Microplastics (MPs) are persistent and ubiquitous contaminants threatening natural ecosystems and impairing organisms at different biological levels of organization. Their durability and degradation rate pose a great concern in the scientific community, and thus, several techniques have been used to detect MPs effectively.

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The exploration of perovskite compounds incorporating actinide and divalent elements reveals remarkable characteristics. Focusing on PbBkO, RaBkO, and SrBkO, these materials were studied using density functional theory (DFT) via the CASTEP code to analyze their electronic, optical, and mechanical properties. The results show semiconductor behavior, with respective band gaps of 1.

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The open nature of Wireless Sensor Networks (WSNs) renders them an easy target to malicious code propagation, posing a significant and persistent threat to their security. Various mathematical models have been studied in recent literature for understanding the dynamics and control of the propagation of malicious codes in WSNs. However, due to the inherent randomness and uncertainty present in WSNs, stochastic modeling approach is essential for a comprehensive understanding of the propagation of malicious codes in WSNs.

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Overcoming Nanosilver Resistance: Resensitizing Bacteria and Targeting Evolutionary Mechanisms.

ACS Nano

December 2024

School of Environment, Beijing Normal University, 19 Xinjiekouwai Street, Haidian District, Beijing 100875, China.

The rapid spread of antimicrobial resistance poses a critical threat to global health and the environment. Antimicrobial nanomaterials, including silver nanoparticles (AgNPs), are being explored as innovative solutions; however, the emergence of nanoresistance challenges their effectiveness. Understanding resistance mechanisms is essential for developing antievolutionary strategies.

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Switched Reluctance Motor (SRM) has a very high potential for adjustable speed drive operation due to their cost-effectiveness, high efficiency, robustness, simplicity, etc. Now a days SRMs are widely used in automotive industries as traction motors in electric vehicles and hybrid electric vehicles, air-conditioning compressors, and for other auxiliary services. In this article, a novel super twisting sliding mode controller (STSMC) is proposed to improve the performance of an SRM for reducing the ripple in speed and torque.

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The present investigation provides an easy and affordable strategy for fabrication of functional ceramics BiNaTiO-SrFeO (BNT-SrF5) thick films on a flexible, inexpensive and electrically integrated substrate using electrophoretic deposition process (EPD). EPD is a widely accepted, environmentally friendly method for applying coatings from a colloidal suspension to conductive substrates. Lead-free ferroelectric BNT-SrF5 powder was synthesized by solid state method to fabricate bulk samples and thick films (30-160 μm) by EPD process.

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A novel two-parameter continuous model titled the entropy-transformed Weibull (ET-W) distribution has been developed via the entropy transformation. A new framework has been investigated and found to meet the criteria of the probability function. By significantly improving the functional shape and having the ability to model the most likely form of the hazard rate function, this novel modification has increased the adaptability of typical model.

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Weather recognition is crucial due to its significant impact on various aspects of daily life, such as weather prediction, environmental monitoring, tourism, and energy production. Several studies have already conducted research on image-based weather recognition. However, previous studies have addressed few types of weather phenomena recognition from images with insufficient accuracy.

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Antiphospholipid syndrome (APS) is associated with recurrent pregnancy morbidity, yet the underlying mechanisms remain elusive. We performed multifaceted characterization of the biological and transcriptomic signatures of mouse placenta and uterine natural killer (uNK) cells in APS. Histological analysis of APS placentas unveiled placental abnormalities, including disturbed angiogenesis, occasional necrotic areas, fibrin deposition, and nucleated red blood cell enrichment.

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Investigation of factors affecting the sound absorption behaviour of 3D printed hexagonal prism lattice polyamide structures.

Sci Rep

December 2024

Faculty of Mechanical Engineering, Department of Machining, Assembly and Engineering Metrology, VSB-Technical University of Ostrava, Ostrava-Poruba, 708 00, Czech Republic.

The aim of this work is to investigate the sound absorption properties of open-porous polyamide 12 (PA12) structures produced using Selective Laser Sintering (SLS) technology. The examined 3D-printed samples, fabricated with hexagonal prism lattice structures, featured varying thicknesses, cell sizes, and orientations. Additionally, some samples were produced with an outer shell to evaluate its impact on sound absorption.

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The binding free energy of hydrogen-bonded complexes is generally inversely proportional to the solvent dielectric constant. This occurs because the solvent-accessible surface area of the complex is always smaller than that of the individual subsystems, leading to a reduction in solvation energy. The present study explores the potential for stabilizing hydrogen-bonded complexes in a solvent with higher polarity.

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Introduction: It is hypothesized that systemically administered antibiotics penetrate wound sites more effectively during negative pressure wound therapy (NPWT). However, there is a lack of clinical data from patients who receive NPWT for deep sternal wound infection (DSWI) after open-heart surgery. Here, we evaluated vancomycin penetration into exudate in this patient group.

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Interval variational approach for production control and waste reduction using artificial hummingbird algorithm.

Sci Rep

December 2024

Centre for Artificial Intelligence Research and Optimisation, Torrens University Australia, Fortitude Valley, Brisbane, QLD, 4006, Australia.

Nowadays, consumers show more interest towards eco-friendly products. To meet this demand, however, manufacturing processes often generate a lot of hazardous waste, which creates challenges for companies. To tackle these issues, this work develops an optimization model to help companies with managing production, reduce waste, and maintain green product standards.

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This paper investigates the performance of hybrid radio frequency/free space optical (RF/FSO) systems combined with non-orthogonal multiple access communications technology. We examine a scenario where the source and destination are separated by a large distance, with no direct link between them. The relay, denoted R, operates using the decode-and-forward (DF) protocol.

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Fractional nonlinear partial differential equations are used in many scientific fields to model various processes, although most of these equations lack closed-form solutions. For this reason, methods for approximating solutions that occasionally yield closed-form solutions are crucial for solving these equations. This study introduces a novel technique that combines the residual function and a modified fractional power series with the Elzaki transform to solve various nonlinear problems within the Caputo derivative framework.

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While car exhaust emissions in the EU are clearly decreasing, the future of non-exhaust emissions looks more pessimistic. The relative importance of the latter is thus expected to increase in terms of air quality and human health. The aim of the study was to assess regional and seasonal differences in the chemical composition of road dust across the Czech Republic and the health impact of its resuspension, with special respect to polycyclic aromatic hydrocarbons and metals.

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Benefits of Using Design Patterns on Microcontrollers in Implemented IoT Applications.

Sensors (Basel)

December 2024

Department of Control Systems and Instrumentation, VSB-Technical University of Ostrava, 70800 Ostrava, Czech Republic.

As part of our research for microcontroller software support, we have developed a modular framework that utilizes previously unimplemented architectural principles for developing applications on microcontrollers. These principles are still a privilege of enterprise and server applications. The paper describes the benefits of a new architectural approach to developing applications on microcontrollers and describes the most common application scenarios along with examples of IoT application development using a framework with design pattern architecture and SOLID principles.

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Powering Agriculture IoT Sensors Using Natural Temperature Differences Between Air and Soil: Measurement and Evaluation.

Sensors (Basel)

November 2024

Department of Cybernetics and Biomedical Engineering, VSB-Technical University of Ostrava, 17. listopadu 2172/15, 708 00 Ostrava-Poruba, Czech Republic.

As the need to monitor agriculture parameters intensifies, the development of new sensor nodes for data collection is crucial. These sensor types naturally require power for operation, but conventional battery-based power solutions have certain limitations. This study investigates the potential of harnessing the natural temperature gradient between soil and air to power wireless sensor nodes deployed in environments such as agricultural areas or remote off-grid locations where the use of batteries as a power source is impractical.

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