Publikační činnost VŠB-TUO ve Web of Science / Publications of VŠB-TUO in Web of Science

Permanent URI for this collectionhttp://hdl.handle.net/10084/56138

Kolekce obsahuje bibliografické záznamy článků akademických pracovníků VŠB-TUO v časopisech indexovaných ve Web of Science od roku 1990 po současnost. Odkaz na Web of Science je funkční ze sítě VŠB-TUO, vzdálený přístup viz web ÚK VŠB-TUO.

Do kolekce jsou zařazeny:

a) publikace, u nichž je v originálních dokumentech jako působiště autora (adresa) uvedena Vysoká škola báňská – Technická univerzita Ostrava (VŠB-TUO),

b) publikace, u nichž v originálních dokumentech není v adrese VŠB-TUO uvedena, ale autoři prokazatelně v době jejich zpracování a uveřejnění působili na VŠB-TUO.

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Now showing 1 - 20 out of 8128 results

Untersuchung von Überregulierungen im Brandschutz durch Vorschriften und Genehmigungsverfahren/Analyzing overregulation of fire protection by regulations and approval procedures
(VDI Fachmedien, 2024) Brauns, Moritz
Im vorliegenden Beitrag wird das Vorhandensein von Überregulierungen innerhalb präskriptiver Anforderungen durch bauordnungsrechtliche Vorschriften und durch Forderungen innerhalb von Genehmigungsverfahren untersucht. Das brandschutztechnische Sicherheitskonzept von Gebäuden wird durch materielle Anforderungen unter Berücksichtigung von Schutzzielen mit bauordnungsrechtlichen Vorgaben bundeslandabhängig festgelegt. Daneben werden Forderungen an den Brandschutz auch innerhalb von Genehmigungsverfahren gestellt. In dieser Untersuchung erfolgt die Identifizierung von Überregulierung mittels deskriptiver Statistik, statistischer Inferenz und qualitativer Inhaltsanalyse basierend auf einer Umfrageerhebung. Die materiellen Anforderungen können dabei weitestgehend nicht als überreguliert bestätigt werden. Vielmehr besteht ein generelles Empfinden zur Überregulierung in Bezug auf die materiellen Anforderungen und in Genehmigungsverfahren, welches sich in bestimmten materiellen Anforderungsbereichen und Gebäudetypen widerspiegelt und dabei in Abhängigkeit der Prüfinstitution steht.
Window function expression: Let the self-join enter
(Association for Computing Machinery, 2024) Bača, Radim
Window function expressions (WFEs) became part of the SQL:2003 standard, and since then, they have often been implemented in database systems (DBS). They are especially essential to OLAP DBSs, and people use them daily. Even though WFEs are a heavily used part of the SQL language, the amount of research done on their optimization in the last two decades is not significant. WFE does not extend the expressive power of the SQL language, but it makes writing SQL queries easier and more transparent. DBSs always compile SQL queries with WFE using a sequence of partition-sort-compute operators, which we call a linear strategy. Plans resulting from the linear strategy are robust and, in many cases, efficient. This article introduces an alternative strategy using a self-join, which is not considered in the current DBSs. We call it the self-join strategy, and it is based on an SQL query transformation where the result query uses a self-join query plan to compute WFE. One output of this work is a tool that can automatically perform such SQL query transformations. We created a microbenchmark showing that the self-join strategy is more effective than the linear strategy in many cases. We also performed a cost-based experiment to evaluate the query optimizers' ability to select an appropriate strategy. The article's main aim is to show that usage of the self-join strategy for queries with WFE is beneficial if selected in a cost-based manner.
Variability of material solutions for the perimeter walls of buildings in post-industrial settlements as part of energy rehabilitation and achieving carbon neutrality
(MDPI, 2024) Afsoosbiria, Hamed; Kubečková, Darja; Musenda, Oskar Kambole; Mohamed, Khaled
Post-industrial sites are a part of many cities. The impacts of industrial activities are not only evident in the area where the activity took place, but also affect the buildings within these areas. Buildings that served the industry in the past were built mainly by mass construction methods. From today's point of view, these buildings are unsatisfactory in terms of typology, operation, and energy. In particular, energy rehabilitation is a way to restore industrial buildings and bring them to a full-fledged state. This issue is documented in a case study of a city affected by underground mining activity and on a selected skeleton construction. Given that industrial buildings have heavy or mass structures where some elements like beams and columns are damaged, it is crucial to consider not only energy solutions, but also the structural and architectural aspects of these buildings. In terms of thermal engineering and energy, including the renovation of structures, a software-supported evaluation of three material variants for the envelope walls of the skeleton construction from the 1970s was conducted. This study evaluates the thermal performance of conventional, proposed, and traditional wall designs by analysing their U-values, thermal resistance, and structural advantages. The results reveal that the conventional wall, featuring a 150 mm EPS 70 NEO insulation layer, achieves the lowest U-value, outperforming the proposed wall by a factor of 1.2 in thermal resistance. Both designs significantly reduce U-values compared to traditional walls, by factors of 6.55 and 5.40, respectively. Despite a 23% reduction in thickness relative to the conventional wall (and 44% compared to traditional walls), the proposed wall demonstrates robust thermal performance. Further benefits include reduced structural dead load, with the conventional and proposed walls being 3.70 times lighter per square meter than traditional walls. This reduction can decrease foundation, column, and beam dimensions, optimizing building design. Thermal bridging analysis highlights superior corner insulation in conventional walls due to higher surface temperatures, while the proposed wall maintains effective insulation with surface temperatures close to indoor conditions. Overall, the findings underscore the importance of advanced materials in achieving efficient thermal performance while balancing architectural and structural demands. The results achieved from the experimental work show that industrial buildings can be effectively energy-renovated in a way that complies with legislative documents, successfully extends the physical life of the frame structures, and contributes to carbon neutrality.
Assessment of gravity deportment of gold-bearing ores: gravity recoverable gold test
(MDPI, 2024) Šigut, Oldřich; Široký, Tomáš; Janáková, Iva; Střelecký, Radek; Čablík, Vladimír
This study investigated the potential of low-grade gold deposits in modern mining, particularly in the context of declining high-grade resources. The primary method for processing these ores was gravity separation with the Knelson concentrator. A GRG test (gravity recoverable gold test) was conducted on two gold-bearing samples: a polymetallic Cu-Zn-Au ore from Zlaté Hory–Západ (Czech Republic) containing refractory gold and an ore with free gold from Kašperské Hory (Czech Republic). The study evaluated the effectiveness of the GRG test for gold recovery from these ores. The results showed that the Kašperské Hory sample predominantly contained relatively large gold grains, with recovery rates dropping significantly upon finer comminution. In the sample from the Zlaté Hory–Západ deposit, the greatest GRG release occurred in the first and last test stages, suggesting that larger sulfide grains with bound gold passed predominantly in the first stage, while fine gold with residual sulfides passed in the third. Both samples achieved high overall GRG recovery rates, with 64.2% for Kašperské Hory and more than 66% for Zlaté Hory–Západ, demonstrating the efficacy of centrifugal concentrators for both ores.
Sustainable management of cities with a focus on the spread of pollution in the built environment using information modeling
(MDPI, 2024) Szeligová, Natálie; Faltejsek, Michal; Teichmann, Marek
The sustainable development of settlements is increasingly linked to the development of information technologies, which can help identify critical and risky locations based on already detected information. By properly utilizing the advantages of individual systems, effective simulations can be created that will help municipal administrators ensure the expected quality of the environment or mitigate the impacts of the negative effects of the external environment. This article presents an example of the synthesis of several systems used in building information modeling and uses them for modeling and simulating external factors in the built environment. By appropriate application of the methods, places of interest that are affected by the negative effects of air flow, or the spread of pollution through the built environment, were illustratively visualized. The presented study was created based on publicly available data on air pollution in the territory of Ostrava city.
A novel membrane-inspired evolutionary algorithm framework for VRPTW
(Springer Nature, 2026) Bai, Zhonghai; Snášel, Václav; Mirjalili, Seyedali; Vo, Bay; Kong, Lingping; Wang, Xiaopeng, xiaopeng
The vehicle routing problem with time windows (VRPTW) has gained much attention recently due to its wide application in operations research and logistics. VRPTW has been proven to be an NP-hard problem whose optimal solution is computationally costly. Scholars have proposed many methods, such as exact algorithms, heuristics, and metaheuristics, to find near-optimal solutions for the VRPTW. Exact algorithms are limited to small-scale problems, while heuristic algorithms and metaheuristics often converge to locally optimal solutions, despite their applicability to larger-scale problems. This paper proposes a novel membrane-inspired evolutionary algorithm framework (MEAF) consisting of isolated evolutionary rules, communication output rules, communication input rules, fusion-exchange information operation, and membrane dissolution rules. By leveraging the advantages of multiple metaheuristics algorithms and avoiding the pitfalls of local optima, MEAF offers a promising solution to address complex problems. The effectiveness of the proposed MEAF is verified by applying three classical metaheuristics, namely Genetic Algorithm (GA), Ant Colony System (ACS), and Particle Swarm Algorithm (PSO), to solve the VRPTW problem. The experiments are run on 56 instances of Solomon with 100 client benchmarks. The evaluation of the experimental results combined with the mean and standard deviation values show that the algorithm performs better in 54 out of 56 instances, demonstrating the effectiveness and stability of the proposed algorithm.
The economic and environmental dimension of sustainable development and evaluation of selected areas in EU countries
(Centre of Sociological Research, 2025) Halásková, Martina; Gavurová, Beáta; Gavurová, Beáta; Pomp, Marek
The paper discusses current issues of economic policy in the context of the initial conditions of sustainable development. The aim of the article is to map the view of sustainable development, to evaluate its selected areas in the economic and environmental dimension and their impact on economic development in EU countries. Using a panel data analysis in the years 2010-2022, the influence of selected areas (indicators) of sustainable development in the context of economic development is examined in EU countries. The results showed the greatest positive impact of economic sustainability indicators in the field of circular economy-Resource productivity and Material footprint in the context of economic development. On the other hand, the greatest negative impact on the economic development of EU countries is associated with share of environmental taxes in total tax revenues and circular material use rate. At the same time, the results confirmed certain differences in the impact of the examined areas of economic and environmental sustainability between EU countries with a higher and lower economic level than the EU average. The findings this research demonstrate the importance of specific areas of economic and environmental sustainability in the examined groups of EU countries.
Effect of build-up strategy and selective laser melting process parameters on microstructure and mechanical properties of 316L stainless steel
(MDPI, 2025) Żaba, Krzysztof; Balcerzak, Maciej; Pałka, Paweł; Čada, Radek; Trzepieciński, Tomasz; Szczepańska, Martyna
Additive manufacturing, or 3D printing, is a method for creating three-dimensional objects layer-by-layer based on a digital model. This article presents the results of research on selective laser melting (SLM) of 316L stainless steel powder. Its aim is to investigate the relation between the mechanical properties of SLM-fabricated 316L steel samples obtained from uniaxial tensile tests and the SLM process parameters including the build-up strategy. Four different configurations of 3D printing orientation relative to the build platform were considered. The variable parameters of the SLM process were laser power and laser scanning speed. The morphology of the external surfaces and the microstructure of the SLM-processed samples were examined. The results show that samples printed in the longitudinal and transverse configurations had the highest tensile strength. Samples printed in the vertical and diagonal configurations had the greatest dispersion of values of mechanical parameters. The main difference in mechanical properties after doubling the SLM process parameters was a decrease in elongation for samples printed in the longitudinal configuration and an increase in this value for samples printed in the transverse configuration. The use of higher laser powers and laser scanning speeds guarantees a more compact, non-porous microstructure of SLM-processed samples.
New approach to assessing nanofiber-based air filters efficiency across variable airflow velocities
(Elsevier, 2025) Dvorský, Richard; Bednář, Jiří; Vilamová, Zuzana; Šimonová, Zuzana; Svoboda, Ladislav
Filtration is a fundamental method in aerosol science for separating unwanted particles, mainly through air filters. Since the onset of the SARS-CoV-2 pandemic in 2019, there has been an increased demand for high- efficiency, low-cost nanofiber-based respirators capable of filtering particles within the size range of viruses and bacteria. The quality factor QF is the critical parameter for evaluating these respirators' practical effectiveness. QF integrates filtration efficiency with a tolerable pressure drop for the respiratory process. Typically, this pressure drop is reported as a function of the flow rate for a given respirator. However, the physical mechanism of filtration is governed by the mean frontal airflow velocity, which depends not only on the flow rate but also on the membrane area, a parameter often unknown in practical applications. The aerosol flow rate influences filtration efficiency and pressure drop through the membrane, yet a comprehensive physical description of this process has been lacking. Therefore, we developed a mathematical-physical model for filtration using a nanofibrous membrane that accounts for all relevant physical mechanisms. This model provides a more accurate definition of the quality factor. Our findings indicate that filtration efficiency does not reach 100 %, even at near-zero air velocities, and that efficiency approaches an asymptotic plateau at high velocities. When fitted to experimental data from various filters using a three-parameters approach, the model's predictions show strong agreement, particularly within the central region of the uncertainty band.
Possibility of high-speed ultrasonic detection of the internal material defects in rails
(MDPI, 2025) Chałko, Leszek; Antolik, Łukasz; Rucki, Miroslaw; Trochta, Miroslav
Highlights What are the main findings? At higher speeds, the quality of acoustic coupling in ultrasonic railway inspection systems is highly dependent on the applied fluid flow; The pressing force exhibited a less significant impact on the acoustic coupling at high speeds. What are the implications of the main findings? Proper control of the liquid flow rate and the pressing force makes it possible to keep reliable ultrasonic measurements at high speeds; The experimental results indicated that it was possible to keep the high quality of the ultrasonic signal at speeds of 120 km/h, which is three times higher than usual; Flaw detection of working rails is possible in short time spans between fast passenger trains.Highlights What are the main findings? At higher speeds, the quality of acoustic coupling in ultrasonic railway inspection systems is highly dependent on the applied fluid flow; The pressing force exhibited a less significant impact on the acoustic coupling at high speeds. What are the implications of the main findings? Proper control of the liquid flow rate and the pressing force makes it possible to keep reliable ultrasonic measurements at high speeds; The experimental results indicated that it was possible to keep the high quality of the ultrasonic signal at speeds of 120 km/h, which is three times higher than usual; Flaw detection of working rails is possible in short time spans between fast passenger trains.Abstract Quick and reliable in situ non-destructive assessment of the material structure is especially critical in the case of measurement of rail defects concerning the demands of quick, uninterrupted transportation and safety. This paper presents the test results of a patented measuring head that is able to perform ultrasonic rail defect detection at speeds of up to 120 km/h. The experimental data was collected and discussed. Statistical analysis was performed in terms of bottom echo drop as a function of velocity, pressing force, and film thickness between the sensor and the rail material surface, as well as the coupling fluid stream intensity. The results proved the feasibility of the device for usage at high speeds for the state monitoring of rails in service.
Data analysis in demand forecasting: a case study of poetry book sales in the european area
(Vysoká škola ekonomická v Praze, Fakulta podnikohospodářská, 2024) Kolková, Andrea
Logistics concepts are becoming less functional nowadays. The successful concept of just- in-time manufacturing seems untenable for 21st-century Europe. New ideas and new practices are emerging. One of the major trends in contemporary logistics is the demand- driven enterprise. Managing supply, fields and other processes in a company based on demand requires accurate demand forecasting at the relevant time. Relevant data are necessary for this forecasting. In the time of big data, the problem is not collecting data but evaluating them correctly. Data analytics is of great interest in business. The aim of the paper is to verify the possibilities of demand forecasting using traditional statistical methods (exponential smoothing, ARIMA), more advanced statistical methods (TBATS, etc.), methods based on artificial neural networks and a hybrid method. This is in conjunction with thorough data preparation, especially data normality testing. My research question is to provide, on data that contain a number of outliers, the results and the accuracy of the models when the data are or are not normalized. Demand forecasting for poetry books was chosen for the case study. The data were obtained from Google Trends data, i.e., searches for the topic of poetry for the period from 1 September 2013 to 31 September 2023. The results showed that the selected data contain a number of outliers that recur at regular intervals and are the result of a logical order of demand. The expected result was that data normalization increases the accuracy of the model. A method based on artificial neural networks provided significantly more accurate results. However, the resulting estimated underlying trend remained very similar. The article thus opens a discussion about the necessity of excluding outlying observations in time series where outliers exist at regular intervals. Implications for Central European audience: The article poses fundamental scientific questions for Central Europe. Logistics concepts are developing rapidly in this area and Europe is the creator of significant innovations. Europe is currently facing great competition from foreign companies and new logistics concepts are becoming a necessity. Therefore, many European companies now feel the need to change their logistics processes. One of them may be to switch to an adaptive enterprise based on demand. The practical implications are also based on data from Europe.
Rapid microwave-assisted hydrothermal in situ synthesis of nano-ZnS/ kaolinite nanocomposite: a non-toxic photocatalyst active under UV and sunlight
(Elsevier, 2025) Smijová, Julie; Tokarský, Jonáš; Mamulová Kutláková, Kateřina; Peikertová, Pavlína; Gabor, Roman; Pavlovský, Jiří; Rajhelová, Hana
Clay mineral kaolinite (K) is suitable for the immobilization of nano-ZnS leading to increase in its photocatalytic activity (PA). Two synthesis methods, conventional hydrothermal (H) and microwave-assisted hydrothermal (M), and various reaction parameters (six reaction times, three nZn:nS molar ratios) for nano-ZnS/K nanocomposites were compared. In addition to XRPD, FTIR, DRS and SEM analyses, PA was determined on acid orange 7 under UV irradiation (lambda = 365 nm), and for selected samples also under natural sunlight. After 360 min of UV irradiation, PA 98 % (H; 210 min; 1:1) and 90 % (M; 30 min; 1:1) were reached. Under the sunlight, PA 97 % (H; 210 min; 2:1) and 93 % (M; 20 min; 2:1) were achieved after 540 min, respectively. Lipid peroxidation tests revealed the inhibition of peroxidation for all nanocomposites. The non-toxicity and hight PA under sunlight suggest the potential for outdoor use of nanocomposites in water purification or construction industry.
Cardiorespiratory fitness in young and newly diagnosed patients with multiple sclerosis: A cross-sectional study
(Elsevier, 2026) Adamec, Tomáš; Hudeček, Tomáš; Pastucha, Dalibor; Hradílek, Pavel; Kondé, Adéla; Šilarová, Anna
Background Cardiorespiratory fitness (CRF) is impaired in patients with multiple sclerosis (MS) regardless of age, but evidence is limited among young and newly diagnosed patients. The aim of the study is to assess CRF using a maximal exercise test on a treadmill and to examine the relationships between CRF, physical activity level, fatigue, depression, and quality of life (QoL) in young patients newly diagnosed with MS. Methods This cross-sectional study analyzed baseline data from a sample of 43 patients with MS who completed a maximal exercise test on a treadmill, measurement of body composition, and answered the Beck Depression Inventory second edition, modified Fatigue Impact Scale, and 36-item Short Form Survey QoL. Results CRF was significantly lower among patients newly diagnosed with MS (aged 20-45 years) compared to normative values (paired Wilcoxon test, p < 0.001). The median absolute differences between normative values and patients' maximal oxygen uptake (VO(2)max) was 8.5 ml/kg/min (interquartile range [IQR]: 2.4-13.4 ml/kg/min), and the median relative differences was 28.3 % (IQR: 7.1-53.9 %). VO(2)max significantly negatively correlated with fatigue (r(S) = -0.37, p = 0.013), but not depression (r(S) = -0.01, p = 0.971). Significant positive correlations were found between VO(2)max and multiple subscales of QoL, including physical functioning (r(S) = 0.50, p = 0.001), social functioning (r(S) = 0.41, p = 0.007), pain (r(S) = 0.41, p = 0.006), and role limitations due to physical health (r(S) = 0.31, p = 0.047). Conclusion Young patients with newly diagnosed MS already exhibit substantially reduced CRF compared with normative values. Lower VO(2)max is associated with higher fatigue and poorer physical and social aspects of QoL. These findings highlight the need for interventions aimed at improving CRF as an integral component of rehabilitation programs.
Microstructure development of powder-based Cu composite during high shear strain processing
(MDPI, 2024) Kunčická, Lenka; Walek, Josef; Kocich, Radim
Commercially pure Cu features excellent electric conductivity but low mechanical properties. In order to improve the mechanical properties of Cu, strengthening elements can be added to prepare alloys or composites featuring enhanced performances. This study focuses on the detailed characterization of the microstructure of a Cu composite strengthened with Al2O3 particles during high shear strain processing. The Cu-Al2O3 mixture was prepared by powder metallurgy and directly consolidated by the intensive plastic deformation method of hot rotary swaging. Samples cut from the consolidated piece were further processed by the severe plastic deformation method of high pressure torsion (HPT). The primary aim was to investigate the effects of varying degrees of the imposed shear strain, i.e., the number of HPT revolutions, microstructure development (grain size and morphology, texture, grain misorientations, etc.) of the consolidated composite; the microstructure observations were supplemented with measurements of Vickers microhardness. The results showed that the added oxide particles effectively hindered the movement of dislocations and aggravated grain fragmentation, which also led to the relatively high presence of grain misorientations pointing to the occurrence of residual stress within the microstructure. The high shear strain imposed into (the peripheral region of) the sample subjected to four HPT revolutions imparted equiaxed ultra-fine grains and an average Vickers microhardness of more than 130 HV0.1.
Effect of reinforced weave patterns on the mechanical performance and wear resistance of wool-epoxy composites
(IOP Publishing, 2026) Jain, Akanksha; Bajpai, Pramendra Kumar; Čep, Robert; Kumar, Ajay; Rattan, Nav; Purohit, Abhilash
This work investigates the effects of fabric weave architecture on the mechanical and tribological properties of sheep wool/epoxy composites manufactured using the hand lay-up technique. Four different weave patterns, namely plain, twill, satin, and basket, were fabricated using a manual handloom and reinforced in an epoxy matrix. The mechanical, interfacial, and wear properties were characterized using tensile, flexural, impact, pull-out, and dry sliding wear tests according to ASTM specifications. Among all the architectures, the satin weave architecture showed the maximum tensile strength of 132.6 MPa, flexural strength, and yield strength due to its lower crimp and higher yarn alignment, which favoured better load transfer. On the other hand, twill architecture offered the best tribological characteristics, and the Taguchi L27 analysis evidenced that the sliding distance is the most dominating parameter that controlling the wear rate. The SEM images showed evidence of good fiber-matrix bonding in satin and twill composites, and the plain and basket architectures revealed higher fiber pull-out and brittle fractures. These observations establish that modifications in weaving architecture could help attain significantly improved stiffness, strength, and wear resistance, and thus wool-reinforced epoxy emerges as a bio-sustainable material for light-weight structural and tribological applications.
Fibrous PVDF membranes modified by anchored g-C3N4@GO composite with enhanced photocatalytic activity
(Elsevier, 2024) Vilamová, Zuzana; Czernek, Pavel; Zágora, Jakub; Svoboda, Ladislav; Bednář, Jiří; Šimonová, Zuzana; Plachá, Daniela; Dvorský, Richard
Recently, the development of fibrous membranes for pollutant filtration from air or water has been a topic of great interest. However, these filters' high and rapid fouling has limited their use. In response, we have prepared photocatalytic active membranes that harness the synergic effect between graphene oxide (GO) and graphitic carbon nitride (g-C3N4). The resulting composite demonstrated the highest photocatalytic activity (k(obs) = 88 x 10(-3) min(-1)). This g-C3N4@GO composite was then carefully deposited on/in an electrospun polyvinyl difluoride (PVDF) fibrous membrane. The reproducible results of the chemical bonding of the composite to the PVDF matrix were evident during photocatalytic experiments after ten Rhodamine B (Rh B) photocatalytic degradation cycles. Importantly, the fiber structure analysis post-reaction did not reveal any fiber cracks or void formation defects, indicating the excellent chemical stability of the PVDF fibrous matrix. This research offers a promising, sustainable, eco-friendly, and efficient solution for removing pollutants from different environments, inspiring further exploration and development in this field.
Strategy and performance of family businesses: Comparison of Pakistan and the Czech Republic
(Wiley, 2024) Subhani, Muhammad Kamal; Mikušová, Marie
In this paper, we observe how effective the use of strategies is in relation to the objectives of family businesses. Data collected in spring 2024 by interviews were processed using DEA. Respondents were owners of small family businesses; 169 valid responses were obtained from each country. The assessment reflected the differences between the countries. For Pakistani companies, the human resources management strategy and the growth and expansion strategy were found to be the most valuable and yielded high production. The most frequent outputs were the relationship between the family and their business, as well as family beliefs and religion. In the case of the Czech owner, there is only a strategy of competitiveness that provides equal output. The results here were related to economic performance. An innovative approach is the use of the DEA method, which sets the production-possibility frontier and thus determines which strategies are currently inefficient.
Design of a distributed power system using solar PV and micro turbine-based wind energy system with a flywheel energy storage
(Springer Nature, 2025) Bhavani, Tharinaematam; Rajababu, Durgam; Irfan, Muhammad; Rakesh, T.; Sekhar, P. Chandra; Flah, Aymen; Kraiem, Habib
As renewable energy sources gain distinction in distributed power generation, micro-grid systems integrating solar photovoltaic (PV), micro-turbine-based wind energy, and flywheel energy storage have developed as sustainable solutions. This paper presents a novel design methodology for a hybrid micro-grid system that optimally integrates these components, ensuring enhanced efficiency, resilience, and stability. In a grid outage or weak-grid scenario, a flywheel provides instant backup until wind/solar/storage catches up. The distributed nature ensures that local power supply is maintained, thereby reducing blackout risks. Flywheels avoid chemical waste, unlike batteries. The proposed hybrid micro-grid system represents an innovative approach to distributed power generation in terms of triple energy sources and storage type is in the form of mechanical and the response speed is ultra fast (few milli seconds), fast response time (milliseconds), ideal for voltage/frequency regulation Handling sudden load changes or source fluctuations high reliability due to multiple backups and high sustainability. This hybrid system is suitable for decentralized operation, which allows each unit to make local decisions. This research contributes to advancing micro-grid technology, supporting the transition towards sustainable and resilient energy infrastructures. A key contribution of this work is the design of a fuzzy logic controller (FLC) for dynamic energy management and control of DC-DC converters. Advanced control algorithms (like fuzzy logic, manage real-time source prioritization, power quality regulation, and energy storage control). It enables multi-input, multi-output decision-making that traditional PID or rule-based controllers can't handle efficiently. Handles nonlinear, variable, and uncertain conditions better than conventional methods. Comparative analysis reveals that the FLC outperforms conventional PID controllers, offering a significantly faster dynamic response and reducing output ripples to a greater extent. This leads to improved power quality, enhanced system life, and optimized energy utilization.
Impact of COVID-19 on kidney transplant outcomes: An 8-year study from the Czech Republic
(International Scientific Information, 2025) Roman, Jan; Jalůvka, František; Jelínek, Petr; Ostruszka, Petr; Hrubovčák, Ján; Havránek, Pavel; Kondé, Adéla; Lys, Zdeněk; Drápela, Martin; Procházka, Václav
Background: The Coronavirus disease 2019 (COVID-19) pandemic disrupted transplant programs worldwide. Transplant recipients are especially vulnerable to the effects of SARS-CoV-2 infection due to immunosuppression. This study assessed the impact of the COVID-19 pandemic on kidney transplant outcomes. Material/Methods: We performed a single-center, retrospective cohort study of the kidney transplant program in the Czech Republic. The analysis included 145 recipients transplanted from 138 donors between 2015 and 2022. Cohorts were defined by donor procurement before the pandemic (n=94) or during the pandemic (n=44). The analysis focused on short- and long-term graft and patient outcomes of both groups. Results: No significant differences were found in postoperative kidney graft function (P=0.160) or overall survival before and during the pandemic. The 1- and 3-year survival rates before the pandemic were 96.0% and 90.9%. During the pandemic, they were 97.8% at both time points (P=0.092). Deathcensored failure-free survival was 95.9% and 90.4% at 1 and 3 years before the pandemic versus 95.6% at 1 and 3 years during the pandemic, respectively (P=0.377). Estimated glomerular filtration rate at 7 days (P=0.233) and 1 month (P=0.893) did not differ between vaccinated and non-vaccinated recipients. Conclusions: The COVID-19 pandemic had no significant impact on the short- or long-term outcomes of the kidney transplantation program. These data support sustaining standard kidney transplantation programs during health crises.
Distributed sensing with nanoparticle-doped fibers in standard OTDR systems: Validation and performance analysis
(Elsevier, 2026) Leal-Junior, Arnaldo; Kepák, Stanislav; Pedruzzi, Eduarda; Nedoma, Jan; Martinek, Radek; Blanc, Wilfried
This paper presents the implementation of enhanced backscattering optical fibers in optical time-domain reflec tometry (OTDR). The increase in the backscattering is achieved by doping the fiber core with nanoparticles, resulting in the so-called nanoparticle-doped optical fibers (NPFs). The so-called NPF-OTDR sensor system takes advantage of the higher scattering of the NPFs to increase the spatial resolution and strain sensitivity of the distributed sensor system. The wavelength-dependent optical attenuation is measured over a wide range of wave lengths using the cutback method to evaluate the operational wavelength for the OTDR. In this case, the results indicated smaller attenuation in 1310 nm than at the other operational wavelengths of the OTDR system (i.e., 1550 nm and 1625 nm). For this reason, the OTDR is applied at the 1310 nm wavelength for different strains applied along the optical fiber (with 1 m separation between them). The results for strain estimation showed relative errors of around 3%, whereas the strain position estimation is around 0.24 m. These results indicate the feasibility of the proposed system with a potential spatial resolution of around 0.5 m (which can be even lower depending on the OTDR setup). Thus, the advantages of the OTDR using the NPF result in a better sensor system performance when compared with the standard optical fibers, significantly enhancing the conventional OTDR capabilities in terms of resolution with even comparable performance to specialty OTDR systems at a lower cost and with a simpler design.

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