Tomas Bata University in Zlín
Institutional repository of Tomas Bata University LibraryNot a member yet
10673 research outputs found
Sort by
Effect of two-stage water addition on consistency of processed cheese: Physicochemical, mechanical, thermal, and organoleptic approach
Get PDFThe current study investigated the impact of two-stage water addition on the selected properties of processed cheese (PC). In particular, the above-mentioned novel approach involved adding water in two stages during the PC manufacturing process. The effects of this process on the physicochemical, viscoelastic, textural, tribological, thermal, and organoleptic properties of PC were evaluated. For all examined PC samples, the elastic modulus consistently dominated over the viscous modulus (G′ > G″) across the entire frequency range. Moreover, it was observed that a smaller amount of initial water addition during the melting process resulted in a slight increase in the values of both viscoelastic moduli. The control sample exhibited the lowest lightness values, while it also showed the highest level of yellow coloring, suggesting that the two-stage addition of water affected the color of the PC samples. The results showed that the two-stage addition of water significantly influenced the physicochemical, viscoelastic, textural, tribological, thermal, and organoleptic properties of PC, leading to a modified texture, and thermal stability. Moreover, firmer PC products were obtained when a greater initial water level (first dosage; in the range of 60 to 90%) was utilized. This study could provide valuable information on the development of high-quality PC products with tailored functional properties, which can be important for the dairy industry.Tomas Bata University in Zlín, TBU, (IGA/FT/2025/007); Tomas Bata University in Zlín, TBUInternal Grant Agency at Tomas Bata University in Zlin (Zlin, Czech Republic) [IGA/FT/2025/007
Lokomat vs. conventional therapy—Impact on gait symmetry in hemiparetic patients: Preliminary clinical study
Get PDFBackground/Objectives: One of the primary goals of neurorehabilitation after stroke is gait reeducation, as it provides the patient with greater autonomy and enhances their safety in daily activities. A preliminary clinical study was undertaken to determine whether robotic gait reeducation using the Lokomat device is more effective than conventional therapy in achieving gait symmetry. Methods: The research group consisted of 107 patients, with an average age of 63.54 years, all in the subacute stage of hemiparesis. These patients underwent 4 weeks of neurorehabilitation and were assigned into experimental and control groups. The patients in the experimental group underwent neurorehabilitation (20 sessions) and twice-weekly walking on the Lokomat device (10 sessions). The control group received equivalent neurorehabilitation and conventional gait reeducation. We monitored the return of ideal limb loading (to a 50:50 ratio) and the restoration of the step length on the paretic limb to a physiological length (73 cm), as well as the subsequent restoration of gait symmetry. The measurements were performed using the HP Cosmos Zebris Treadmill FDM-T device. The Wilcoxon Signed Rank test was conducted within each group to analyze the effectiveness of gait reeducation before and after therapy. To compare the results between the two groups, the Mann–Whitney test (α = 0.05) was employed. Results: There was no significant difference between the robotic and conventional therapy groups (p = 0.432 (>0.05)). A significant change occurred only in the control group in the 50:50 limb loading parameter (p = 0.042). There were no significant changes in the other parameters. Conclusions: Under the conditions of our study, robot-guided gait reeducation did not appear to be more effective than conventional therapy. The monthly duration of gait reeducation is insufficient to achieve a symmetrical gait in patients with spastic hemiparesis.Kultúrna a Edukacná Grantová Agentúra MŠVVaŠ SR, KEGA, (005KU-4/2024); Kultúrna a Edukacná Grantová Agentúra MŠVVaŠ SR, KEGAProject KEGA [005KU-4/2024
On the friction and lubrication of 3D printed Ti6Al4V hip joint replacement
Get PDFThe present study investigates the tribological performance of 3D printed Ti6Al4V total hip replacements (THR) compared to conventionally produced THRs from CoCrMo and FeNiCr alloys. The objective was to evaluate the suitability of 3D printed titanium alloy, with and without DLC coating, for THR rubbing surfaces and to investigate the potential benefits of 3D printing technology for friction and lubrication. A pendulum hip joint simulator was employed to replicate the swinging motion of a hip joint, thereby enabling the measurements of coefficient of friction (COF) and the observation of lubricant film formation under realistic conditions between the metal femoral head and acetabular cup. The experiments demonstrated that additive manufacturing enables the creation of specific surface topographies that can enhance protein adsorption, but also introduce surface imperfections negatively affecting tribological properties. The elevated surface roughness of additively manufactured femoral heads did not inevitably result in an increase in COF and was comparable to that of conventionally manufactured femoral heads. The additively manufactured Ti6Al4V head without DLC coating also exhibited a more rapid increase in lubricant film thickness during dynamic motion. In conclusion, the findings indicate that while 3D printing offers promising advancements in implant customization and material properties, its application requires careful consideration of surface finishing and coating methods to achieve optimal tribological performance.Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT; Call Excellent Research; Programme Johannes Amos Commenius; Grantová Agentura České Republiky, GAČR, (22-02154S, CZ.02.01.01/00/22_008/0004634); Grantová Agentura České Republiky, GAČRCzechELib Transformative Agreement; Czech Science Foundation [22-02154S]; Programme Johannes Amos Commenius, Call Excellent Research [CZ.02.01.01/00/22_008/0004634
Impact of powder bed fusion printing process parameters on the achieved quality of PA12 manufactured parts
Get PDFThe study investigates the impact of process parameters in the additive manufacturing technology of powder bed fusion on the properties of manufactured parts. Through experimental analysis, we examine the impact of layer height, laser power, chamber temperature, and sample positioning on surface roughness, tensile strength, and various geometric and dimensional parameters. The samples fabricated from PA12 material are produced using the Sinterit Lisa device, which offers specific parameter adjustment capabilities but lacks precise value setting. The subsequent experimental phase consists of nine carefully designed experiments employing the Taguchi method. We used regression analysis to quantify the impact of individual process factors. Our results reveal significant effects of parameter variations on the final quality of printed objects. Furthermore, these results also underscore the critical importance of model orientation within the printing chamber, influencing achieved tensile strength, surface roughness, and roundness geometric properties. Notably, laser power has a notable impact on the dimensional accuracy of manufactured parts. However, according to our findings, it does not affect surface roughness. Moreover, we observe that laser power, when coupled with chamber temperature, influences the achieved strength of the examined samples. The optimization of these parameters holds promise for enhancing the mechanical properties, geometric properties as well as better surface quality of the final samples. This study offers valuable insights into understanding the laser sintering process better and provides practical guidance to optimize the production process based on this additive manufacturing technology.Ministry of Education, Science, Research and Sport; Verification for the Measurement of Selected Parameters of Ti Implants in the Manufacturing Process, (APVV-20-0561)Agentra na Podporu Vskumu a Vvoja [APVV-23-0366, APVV-22-0328, APVV-20-0561
A comparative study of one-step and multi-step numerical methods for solving ordinary differential equations in water tank drainage systems
Get PDFNumerical methods are essential for solving differential equations in applications such as water drainage systems, where precise water level control is critical for industrial and environmental processes. This study compares one-step numerical methods naming explicit Euler, implicit Euler, implicit midpoint, modified Euler, and fourth-order Runge-Kutta (RK4) with multi-step numerical methods, including Adams-Bashforth, Adams-Moulton, and Predictor-corrector schemes, to solve ordinary differential equations for water tank drainage systems. The analysis focuses on accuracy, stability, computational efficiency, and optimal step size selection. MATLAB scripts and Python (Google Colab) were used to evaluate each method's performance by calculating local and global errors, with detailed analyses of error versus step size, error versus computational effort, and computational effort versus step size. The results reveal that multi-step numerical methods provide superior accuracy and stability for long-term simulations but require greater memory resources, whereas one-step numerical methods are computationally faster but sensitive to step size selection, significantly influencing solution accuracy. This study offers practical recommendations for selecting numerical methods based on application-specific requirements, providing insights into optimizing numerical approaches for systems requiring precise water level control and balancing accuracy with computational efficiency.Univerzita Tomáše Bati ve Zlíně, UTB, (IGA/CebiaTech/2024/001); Univerzita Tomáše Bati ve Zlíně, UTBInternal Grant Agency of the Fakulta aplikovane informatiky, UniverzitaTomase Bati ve Zline [IGA/CebiaTech/2024/001
Recovery of hydrochloric acid and critical raw materials from an effluent of the copper electrorefining process using electromembrane reactors
No full textHighly concentrated acids are used to regenerate ion-exchange resins that are applied for the removal of metallic impurities (i.e. antimony, arsenic and bismuth) from spent copper electrorefining baths, thus generating acidic effluents. In this work, the recovery of critical raw materials and HCl from a real effluent is evaluated by electrodeposition using reactors with and without membrane separators. First, four reduction peaks were detected by cyclic voltammetry, and their correspondence to the pairs Cu(II)/Cu(I), As(III)/As, Sb(III)/Sb, Bi(III)/Bi, and Cu(I)/Cu was confirmed by potentiostatic electrodeposition and elemental analysis of the deposits. A high selectivity towards antimony deposition over arsenic and copper was achieved at the least cathodic applied potential (−0.25 VAg/AgCl), obtaining a deposit with 85 wt% of antimony and bismuth as the second most deposited metal. At more cathodic potentials, deposition of copper takes place and the antimony content in the deposits decreases. Galvanostatic electrodeposition tests were carried out using a three-compartment reactor. Results showed that the transport rate of Cl- ions through the anion-exchange membrane is too slow to recover highly concentrated HCl in a separate compartment. However, electrodeposition of the main elements present in the real effluent makes possible obtaining impurity-free HCl (4.8 M) in the cathodic compartment. The complete recovery of antimony (100 %) and almost complete recovery of bismuth (95 %) and copper (90 %) were achieved after 4 h working at −100 mA·cm−2. Tests conducted with a single-compartment reactor confirmed that formation of chlorine gas at the anode causes the redissolution of the metals deposited at the cathode, thus revealing that electromembrane reactors improve the electrodeposition current efficiency.Federación Española de Enfermedades Raras, FEDER; European Regional Development Fund, ERDF; Agencia Estatal de Investigación, AEI, (AEI/10, 13039/501100011033, PCI2019–103535, AEI/10.13039/501100011033); Agencia Estatal de Investigación, AEIAgencia Estatal de Investigacion (Spain) [PCI2019-103535]; FEDER A way of making Europ
One-step fabrication of chitosan/dialdehyde cellulose/polypyrrole composite nanofibers with antibacterial, antioxidant, and immunomodulatory effects
No full textThe study introduces a novel method for fabricating crosslinked chitosan/polypyrrole (PPy) composite nanofibers with covalently anchored PPy. Crosslinking is achieved already during electrospinning by using dialdehyde cellulose (DAC) as a dual-functioning reagent able to simultaneously crosslink chitosan nanofibers and covalently tether PPy nanoparticles by a newly discovered aldol condensation reaction. The presented method eliminates the need for postprocessing steps. It reduces the environmental impact by avoiding toxic organic chemicals while preventing PPy leaching and improving prepared composite nanofibers' mechanical and biological properties. A direct comparison to neat chitosan nanofibres was performed to demonstrate the superiority of prepared composites. The resulting crosslinked CHIT_DAC_PPy composite nanofibers have increased tensile strength, improved stability at low pH, conductivity up to 11 mS/cm, and higher swelling compared to neat CHIT nanofibers. They also possess significantly enhanced antibacterial activity against gram-positive S. aureus, higher antioxidant activity, increased immunomodulatory effects, and substantially higher acceleration of wound healing in vitro. CHIT_DAC_PPy nanofibrous composite thus shows significant potential for fabricating advanced wound dressings.Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT; Grantová Agentura České Republiky, GAČR, (RP/CPS/2024-28/003, RP/CPS/2024-28/001, RP/CPS/2024-28/002, GA24-11534S, 24-11534S); Grantová Agentura České Republiky, GAČR; TBU in Zlín, (IGA/CPS/2025/001)Project of the Czech Science Foundation [GA24-11534S]; Ministry of Education, Youth, and Sports of the Czech Republic [RP/CPS/2024-28/001, RP/CPS/2024-28/003, RP/CPS/2024-28/002]; TBU in Zlin [IGA/CPS/2025/001
Viscoelastic and structural insights into magnetorheological foam fabricated with different volumes of constraint foaming process
Get PDFMagnetorheological (MR) foam, a smart magnetic-responsive flexible polyurethane material, has garnered significant attention for its potential in soft robotics. However, limited studies on its dynamic mechanical and damping properties hinder its development for broader applications. This study investigates the influence of constraint volume foaming process (100 %, 75 %, and 50 % volume) on the properties of MR foam containing 75 wt. % carbonyl iron particles (CIPs) under dynamic mechanical compression and rheological shear testing at frequencies ranging from 0.1 to 10 Hz. Results showed that the constrained foaming MR foam with 50 % volume exhibited the most significant enhancement in storage modulus (E′ and G′), attributed to a more compact CIP distribution, resulting in the lowest initial loss factor (tan ẟ). However, upon increasing frequencies, a notable increase of approximately 20 % in tan ẟ was observed for this MR foam, indicating improved energy dissipation at higher frequencies. In contrast, the free foaming MR foam demonstrated only a 5 % increase in tanδ, highlighting its lower energy dissipation capability. Morphological analysis revealed that constraint volume foaming process produced smaller pores and denser CIP distributions. The compact structure enhanced particle-matrix interactions, increasing friction and contributing to improved damping at elevated frequencies. In summary, the incorporation of constraint volume foaming process significantly enhanced the dynamic mechanical, rheological, and structural properties of MR foam. These advancements broaden its applicability for advanced applications, particularly in soft robotics, where energy dissipation and tunable properties are critical.Higher Institution Centre of Excellence; Ministry of Higher Education, Malaysia, MOHE, (FRGS/1/2022/TK10/UTM/02/75); Ministry of Higher Education, Malaysia, MOHE; Universiti Teknologi Malaysia, UTM, (23H17); Universiti Teknologi Malaysia, UTM; Grantová Agentura České Republiky, GAČR, (23-07244S); Grantová Agentura České Republiky, GAČRHigher Institution Centre of Excellence (HiCOE) program of Ministry of Higher Education (MOHE) Malaysia under HiCOE Research Grant; UTM Fundamental Research Grant [23H17]; Czech Science Foundation [23-07244S
Artificial Size Slicing Aided Fine Tuning (ASSAFT) and Hyper Inference (ASSAHI) in tomato detection
No full textIn the realm of precision agriculture, accurate harvest prediction is vital, as any discrepancies between forecasted and actual yields can lead to significant commercial and logistical challenges. This paper presents a novel deep learning-based approach for detecting and counting tomato fruits using advanced computer vision techniques. Building upon our previously established framework for ultra-wide image acquisition, this approach focuses on a unique patch-cropping technique tailored to tomatoes. This method aligns with the natural clustering of tomatoes, significantly improving object detection in greenhouse settings and thereby enhancing the model's performance in identifying individual fruits. The detection results exhibit a precision of 0.85, a recall of 0.93, and an F1-score of 0.89. Our approach's efficacy is also demonstrated through a case study on harvest prediction in a tomato greenhouse. The proposed methodology exhibited a lower error rate than the agronomist's estimates and proved its practical applicability. These findings suggest that our methodology could substantially contribute to optimizing sustainable farming practices, offering a promising direction for future research and application in the agricultural sector.Internal Grant Agency of Tomas Bata University, Czechia [IGA/CebiaTech/2023/004]; A.I.Lab at the Faculty of Applied Informatics, Tomas Bata University in ZlinFakulta aplikované informatiky, Univerzita Tomáše Bati ve Zlíně, FAI; Internal Grant Agency of Tomas Bata University, (IGA/CebiaTech/2023/004
Quality 4.0 practices toward sustainable excellence in the manufacturing sector
No full textIn the Industry 4.0 context, it is very important for companies to apply a comprehensive and sustainable business model to grow steadily and quickly adapt to the fast-changing environment. Although the existing literature has explored Quality 4.0 by integrating Industry 4.0 tools into the TQM system, the question of how Quality 4.0 practices drive sustainable excellence (SE) remains unexplored. Therefore, to fill the gap, this research aims to investigate the relationship between Quality 4.0 practices and SE as well as the role of digital transformation (DT) and digital leadership in this connection, anchoring on the stakeholder theory, the natural resource-based view (NRBR) theory, and the socio-technical system (STS) theory. The research employs the quantitative Structural Equation Model method to analyse empirical data in the manufacturing industry in Vietnam. The findings demonstrate that Quality 4.0 practices positively influence both digital transformation and SE. This study confirmed the mediating role of digital transformation and the moderating role of digital leadership in the relationship between Quality 4.0 practices and SE. The findings of this study contributed to applications of Quality 4.0 practices and digital transformation to improve SE in the manufacturing sector