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Synthesis and properties of 1.13 nm tobermorite with intercalated Al3+ ions.
No full textCalcium silicate hydrates are used to make some of the best heat-resistant insulating products, which have an operating temperature of 1050 °C. These products are made of 1.13 nm tobermorite and synthetic xonotlite. The first compound can be synthesized from a variety of wastes and by-products from other industries, but these raw materials frequently contain impurities, particularly compounds containing aluminum, which significantly affect the kinetics and properties of the formation of 1.13 nm tobermorite. Several analytical methods have demonstrated that while pure 1,13 nm tobermorite with high crystallinity is more easily formed in mixtures without the addition of aluminum, Al3+ ions initially encourage the formation of 1.13 nm tobermorite at the start of the hydrothermal synthesis before beginning to inhibit the recrystallization of C-S-H(I). 1.13 nm tobermorite shape is similarly influenced by aluminum ions. Within 24 hours, hydrothermal synthesis creates long, thin fibers (needles), which then form into rectangular crystals. Agglomerates, which have crystalline platelets partially covering their surface, predominate in the 24-hour synthesis result when alumina is added. The amorphous aggregates vanish and the crystals get more square as the synthesis time increases
A review of mathematical models in robotics /
No full textIn robotics, much emphasis is placed on mathematical modeling, as the creation, control, and optimization of robots for a wide field of work must be achieved precisely and adaptively. The aim of this paper is to present a systematic and structured approach to the literature review of mathematical models in robotics, critically considering mathematical frameworks that influence and shape robotics in light of current and prevailing trends. The paper underlines the complexities of maintaining accurate dynamic representations in robotic systems, revealing the challenges that arise from numerical simplifications. The study outlines the development of efficient remote-control systems that consider dynamic relationships among the components comprising the robot. The findings of the recent simulation prove that the developed mathematical model effectively supports designing an adaptive control system with artificial intelligence features, especially for autonomous mobile robotics with manipulators that are inherently complex and networked systems. If models are to accelerate robotics progress toward increasingly intelligent, adaptive, and efficient systems, they must learn to overcome some of the computational challenges while leveraging disciplinary synergies
Synthesis, structure and electrocatalytic activity of ZrN coatings on AISI304 stainless steel.
No full textThe paper presents an analysis of literature data on production of hydrogen ant ammonia by electrochemical methods. Methods of zirconium nitride coatings deposition is presented in literature review. ZrN coatings were deposited by magnetron sputtering on AISI304 type stainless steel under different conditions. The structure, morphology and composition oh thin films were performed by instrumental analysis. The electrocatalytic activity of ZrN coatings were performed in 0,1 M KOH electrolyte using various electrochemical analysis techniques. The influence of the synthesis conditions on electrocatalytic activity of zirconium nitride thin films was determined. The highest activity is observed for nanostructured ZrN thin films with a ratio Zr:N = 1:0,73. It has been experimentally established that hydrogen evolution reaction dominates in 0,1 M KOH with N2 electrolyte. The principle technological scheme of alkaline water electrolysis is presented and the main technological parameters for production of 10 MW are calculated. Safety of plant is evaluated
Nanocomposite CuxS on flexible polymers: Raman study /
No full textFlexible polymers modified with copper sulfides have emerged as a novel class of materials, presenting composite structures with remarkable properties suitable for applications in flexible electronics. This study focuses on the deposition of copper sulfide (CuxS) layers onto the surfaces of polyamide and polypropylene through the chemical bath deposition method, employing either 2 or 3 deposition cycles. The objective is to explore the impact of deposition cycles and discern the optimal conditions for the deposition process. Comprehensive analysis of the CuxS thin films entails techniques such as scanning electron microscopy (SEM), Raman spectroscopy, UV-VIS spectroscopy, and X-ray diffraction to shed light on their structural and optical characteristics
Leveraging historical process data for recombinant P. pastoris fermentation hybrid deep modeling and model predictive control development /
No full textHybrid modeling techniques are increasingly important for improving predictive accuracy and control in biomanufacturing, particularly in data-limited conditions. This study develops and experimentally validates a hybrid deep learning model predictive control (MPC) framework for recombinant P. pastoris fed-batch fermentations. Bayesian optimization and grid search techniques were employed to identify the best-performing hybrid model architecture: an LSTM layer with 2 hidden units followed by a fully connected layer with 8 nodes and ReLU activation. This design balanced accuracy (NRMSE 4.93%) and computational efficiency (AICc 998). This architecture was adapted to a new, smaller dataset of bacteriophage Qβ coat protein production using transfer learning, yielding strong predictive performance with low validation (3.53%) and test (5.61%) losses. Finally, the hybrid model was integrated into a novel MPC system and experimentally validated, demonstrating robust real-time substrate feed control in a way that allows it to maintain specific target growth rates. The system achieved predictive accuracies of 6.51% for biomass and 14.65% for product estimation, with an average tracking error of 10.64%. In summary, this work establishes a robust, adaptable, and efficient hybrid modeling framework for MPC in P. pastoris bioprocesses. By integrating automated architecture searching, transfer learning, and MPC, the approach offers a practical and generalizable solution for real-time control and supports scalable digital twin deployment in industrial biotechnology
Exploring the role of organizational factors in shaping managers’ experience through the SCARF model /
No full textThe paper examines the influence of positive and negative organizational factors on the experience of Companies CEOs (hereafter referred to as managers) through the SCARF model framework. Managers play an important role in ensuring process efficiency in the organizations; therefore, the manager's work requires a lot of emotional and psychological resources, which are influenced by various external factors such as the nature of the organization's activity, competitive environment, organizational changes, as well as the managers' characteristics such as management and/or leadership style, behavioral and communication styles. A manager's ability to work effectively with employees, both direct reports and others across the organization, in routine and stressful situations is a critical factor that influences not only the organization's performance and quality outcomes, but also employees' job satisfaction and emotional well-being. This article presents a study that applied the SCARF model to analyze how managers' experiences working with employees are influenced by the SCARF factors: status, certainty, autonomy, relatedness, and fairness. The study aims to explore how these elements are perceived by managers, what they mean in the context of their work, in which situations they are positively or negatively affected, and which of them has the greatest impact on managerial stress. The study revealed that managers tend to invest in building relationships with employees and creating a positive working environment, so the relatedness is one of the key factors that can have positive and negative impacts on the managerial experience working with employees. In contrast, participants perceive autonomy as a 'territory' granted by shareholders, a relatively stable element that does not significantly affect managers' experience in working with employees
Assessing tactors’ active safety in Serbia: a driving simulator study /
No full textThe active safety of tractors remains a major concern in rural road environments, where tractor drivers face high crash risks due to limited vehicle visibility. In Serbia, 1.4% of crashes involve tractors, mainly due to poor visibility (64.3%), lack of beacon lights, unsafe overtaking, and unmarked stopped tractors (14.3% each). These issues reduce safety, increase fuel consumption and emissions, and cause economic losses. A driving simulator study with 117 drivers examined how visibility equipment affects speed perception. The results showed that 20 km/h was best estimated with all visibility aids, while 10 km/h was most accurately judged with only the slow-moving vehicle emblem. These findings emphasize the potential for simple, cost-effective visibility measures to enhance the active safety of tractors in mixed rural traffic conditions. By enhancing tractor visibility, these measures reduce crash risks, minimize unnecessary acceleration and deceleration, and lower fuel consumption and emissions associated with traffic disturbances. Furthermore, by preventing crashes, these solutions contribute to reducing resource consumption in crash-related medical care, vehicle repairs, and infrastructure damage. Integrating improved visibility equipment into rural traffic policy can significantly enhance tractors’ active safety and reduce the risk of crashes in agricultural regions
Influence of niobium substitution on the properties of Pb2Fe2O5 thin films synthesized via reactive magnetron sputtering /
No full textLead ferrite (Pb2Fe2O5) is a promising multiferroic material that exhibits both ferroelectric and magnetic properties at room temperature. This study investigates how substituting niobium and adjusting the synthesis temperature affect the structural, morphological, and ferroelectric properties of lead ferrite thin films deposited via reactive magnetron sputtering. Niobium-substituted PFO films (Pb2Fe2(1−x)Nb2xO5), where x corresponds to Nb2O5 contents of 3 wt.%, 5 wt.% and 10 wt.%, were prepared for this study, and denoted as PFONb3, PFONb5 and PFONb10, respectively. X-ray diffraction analysis confirmed the formation of Nb-substituted PFO phases, while polarization–electric field measurements demonstrated an increase in remnant polarization (Pr), with higher Nb content reaching a maximum Pr of 65 μC/cm2 at 10 wt.% Nb and a substrate temperature of 500 ◦C. Scanning electron microscopy and energy-dispersive spectroscopy revealed a uniform distribution of elements and a well-defined surface structure. These results highlight the need to fine tune synthesis parameters, such as temperature and substitution concentrations, to achieve optimal ferroelectric characteristics
Synthesis and biological evaluation of β-phenylalanine derivatives containing sulphonamide and azole moieties as antiproliferative candidates in lung cancer models /
No full textIn this study, a series of novel β-phenylalanine derivatives were synthesised and evaluated for their anticancer activity. The 3-(4-methylbenzene-1-sulfonamido)-3-phenylpropanoic acid (2) was prepared using β-phenylalanine as a core scaffold. The β-amino acid derivative 2 was converted to the corresponding hydrazide 4, which enabled the development of structurally diverse heterocyclic derivatives including pyrrole 5, pyrazole 6, thiadiazole 8, oxadiazole 11, triazoles 9 and 12 with Schiff base analogues 13 and series1,2,4-triazolo [3,4-b][1,3,4]thiadiazines 14. These modifications were designed to enhance chemical stability, solubility, and biological activity. All compounds were initially screened for cytotoxicity against the A549 human lung adenocarcinoma cell line, identifying N-[3-(3,5-dimethyl-1H-pyrazol-1-yl)-3-oxo-1-phenylpropyl]-4-methylbenzenesulfonamide (5) and (E)-N-{2-[4-[(4-chlorobenzylidene)amino]-5-thioxo-4,5-dihydro-1H-1,2,4-triazol-3-yl]-1-phenylethyl}-4-methylbenzenesulfonamide (13b) as the most active. The two lead candidates were further evaluated in H69 and H69AR small cell lung cancer lines to assess activity in drug-sensitive and multidrug-resistant models. Schiff base 13b containing a 4-chlorophenyl moiety, retained potent antiproliferative activity in both H69 and H69AR cells, comparable to cisplatin, while compound 5 lost efficacy in the resistant phenotype. These findings suggest Schiff base derivative 13b may overcome drug resistance mechanisms, a limitation commonly encountered with standard chemotherapeutics such as doxorubicin. These results demonstrate the potential role of β-phenylalanine derivatives, azole-containing sulphonamides, as promising scaffolds for the development of novel anticancer agents, particularly in the context of lung cancer and drug-resistant tumours
The relationship between physical activity and academic achievement in primary school pupils with hearing impairment /
No full textBackground. Hearing impairment is one of the most frequently occurring diseases in children, both congenital and acquired. It affects approximately 1 to 3 children in every 1000 (Seifert et al., 2005). Objectives. This study aimed to reveal the impact of physical activity on the mathematics achievement of primary school pupils with hearing impairments. Materials and methods. The Children’s Physical Activity Questionnaire (Corder et al., 2009)was used, which is based on the Children’s Leisure Activities Study Survey questionnaire, which includes activities explicit to little children, such as “playing in a playhouse”. The Mathematics Progress Monitoring Test (MPMT) (Kliziene et al., 2024) was adapted for pupils with hearing impairment. The MPMT was used to assess the mathematics achievement of the students who took part in the study. Theywere designed to evaluate each pupil’s achievement level, which, according to the general curriculum, was divided into unsatisfactory, satisfactory, basic, and advanced. The mathematics achievement of pupils with hearing impairment was assessed in four areas of the mathematics curriculum. Results. The posttest results of first-grade primary school pupils with hearing impairments(158.95 MET, min/week) were analyzed to compare average physical activity with the pretest results (125.61 MET, min/week), during physical education lessons. Walking to school (20.39 MET, min/week) and cycling to school (16.85 MET, min/week) showed statistically significant differences (between types of physical activity) in the pretest and posttest according to MET p<0.05. PA helped pupils with hearing impairment to achieve basic results (pretest (5.81 (3.25) posttest (16.84 (2.98); p = 0.000) and advanced results (pretest (0.81 (0.53) posttest (4.18 (0.47); p = 0.002). Conclusions. According to the findings, it was established that properly interpreted and appropriately applied physical activity for primary school pupils with hearing impairment led to statistically significant changes in dependent variables: an increase in pupils’ physical activity and academic achievement. Marked changes were observed in mathematics tasks that required higher-level thinking skills, knowledge, and understanding; distribution of mathematics learning achievement by content such as natural and integer numbers, patterns and relationships, geometry and measurements, data, and statistical probabilities. Higher levels of physical activity resulted in achievement levels changing from satisfactory to basic and advanced