16168 research outputs found
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Production of bitumen modifiers from used tyre rubber.
No full textThe aim of the thesis is to design a continuous bitumen modifier production plant capable of producing 4000 tonnes of modifier per year. To achieve this objective, a literature analysis of scientific articles and studies was carried out. Different types of polymeric modifiers, technological processes and innovations have been reviewed. In collaboration with partners, studies were done to test different modifier formulations and to determine the optimum quantity to reach the threshold values for key parameters such as needle penetration, Fraser brittleness, softening point and elastic recovery. A process line has been designed and a schematic diagram has been drawn showing how the modification of bitumen from used tyre rubber by devulcanisation will be achieved by means of a twin-screw extruder. The structural solutions for the building that meet the requirements were described. Calculations have been made, predicting the main financial and economic indicators. The investment and payback options were assessed. In addition, health and safety requirements were discussed and a plan was drawn up to implement them, and an occupational risk assessment was conducted. An environmental assessment of the company has been prepared, looking at the associated benefits in terms of reducing CO2 and environmental pollution
Properties of laboratory-granulated crystalline urea with microalgae additive and their importance for process modelling.
No full textThe topic of the Master's thesis – Properties of Laboratory-granulated Crystalline Urea with Microalgae Additive and their Importance for Process Simulation. The thesis presents theoretical insights into the positive effects of urea and microalgae on plants and soil, reviews granulation methods for fertilizers, and discusses fertilizer modeling techniques. In the experimental part, urea fertilizers were granulated from raw material mixtures without return material and with 20%, 30%, and 40% return material content. Optimal water amounts, granule strength, granulometric composition, bulk density, and hygroscopicity were determined. The urea granulation technology was examined, and the influence of return material and water content on product properties was analyzed. Studies were conducted on the properties of granulated fertilizers necessary for modeling the granulation process, and the process was modeled using the Altair EDEM 2023 software. The thesis consists of 59 pages and includes a list of tables, a list of figures, an introduction, literature review, experimental section, occupational health and safety considerations, conclusions, and a list of reference
Synthesis and properties of supplementary cementitious materials from biomass fly ash.
No full textThis study aimed to investigate the potential of using biomass fly ash as a supplementary cement material after hydrothermal modification. The treatment of biomass fly ash involved additional grinding and synthesis under various hydrothermal conditions. The variation in the C/S ratio was achieved by mixing different biomass fly ash samples. Samples with C/S ratios of 1 and 1.5 were selected for synthesis. Additionally, cement samples with different amounts of the synthesized additive were examined. The following methods were used in the study: XRD, XRF, ICP-OES, DSC-TG and isothermal calorimetry. It was found that calcium silicate hydrates formed in all biomass fly ash samples after just 2 hours of hydrothermal synthesis at a temperature of 200 °C. The chemical composition analysis of the liquid medium after hydrothermal treatment revealed an exceptionally low content of heavy metals released from the samples. The synthetic additive accelerated the initial hydration of Portland cement. The results of the compressive strength tests suggest that 5–10 % of the cement mass can be replaced with hydrothermally treated biomass fly ash without reducing the compressive strength class of Portland cement samples
A new synthetic approach to the 3,4-dihydro-1H-[1,4]oxazino[4,3-a]indole system from ethyl 1H-indole-2-carboxylates and activated glycerol carbonate /
No full textEffect of modification methods on composition and technological properties of sea buckthorn (Hippophae rhamnoides L.) pomace /
No full textWith the growth of the plant-based food sector, increasing amounts of by-products are generated. Sea buckthorn pomace (SBP), a by-product of juice and other manufacturing products, is rich in bioactive compounds such as phenolics, oligosaccharides, proteins, and dietary fiber. The aim of the study was to evaluate the impact of modification methods, such as enzymatic hydrolysis and supercritical carbon dioxide extraction (SFE-CO2), on the chemical composition and technological properties of SBP. SBP and SBP obtained after SFE-CO2 (SBP-CO2) were enzymatically modified using Pectinex® Ultra Tropical, Viscozyme® L, and Celluclast® 1.5 L (Novozyme A/S, Bagsværd, Denmark). The SBP’s main constituent was insoluble dietary fiber (IDF), followed by crude proteins and lipids (respectively, 58.7, 21.1 and 12.6 g/100 in d.m.). SFE-CO2 reduced the lipid content (by 85.7%) in the pomace while increasing protein and TDF content. Enzymatic hydrolysis decreased the content of both soluble dietary fiber (SDF) and IDF, and increased the content of mono- and oligosaccharides as well as free phenolics, depending on the commercial enzyme preparation used in SBP and SBP-CO2 samples. Celluclast® 1.5 L was the most effective in hydrolyzing IDF, while Viscozyme® L and Pectinex® Ultra Tropical were the most effective in degrading SDF. Enzymatic treatment improved water swelling capacity, water retention capacity, water solubility index, oil retention capacity of SBP and SBP-CO2; however, it did not have a significant effect on the stability of the emulsions. Modification of SBP by SFE-CO2 effectively increased WSC and WSI, however it reduced WRC. These findings highlight the potential of targeted modifications to enhance the nutritional and technological properties of SBP for functional food applications
Evaluation of pressure values of real and virtual compression garments with adhesive stripes /
No full textVirtual prototyping with 3D technology provides valuable insights into comfort and fit through strain, stress, and pressure distribution maps, making it a valuable tool in garment design and development. The aim of this research is to compare pressure values of compression sleeves with adhesive stripes using virtual fit technology and real garment pressure testing. Knitted fabric and adhesive polyurethane film were used to design virtual and real compression sleeves with ”Y” and ”X” shaped film elements, purposely placed according to Kinesio taping techniques. Polyurethane film covered 40% of the product area. The garment pattern design and 3D visualization were accomplished using Modaris (CAD Lectra) software. The pressure values of virtual garments were determined by applying tensile testing results and reducing pattern of the garment in transverse direction to reach 20 mmHg compression that ensured the 1st compression class when primed on a cylinder of 100 mm diameter. Virtual sleeves were fitted on virtual cylinders of various diameters to determine the differences in the pressure values as the size of the body changes. The pressure values were calculated by the Laplace law, using a radius of cylinder and the strain of the material in transverse direction at the garment local points. Compression sleeves were fitted on 100 mm diameter cylinder imitating a curvature of a human limb. FlexiForce sensors were used for direct measurements and determination of the pressure exerted by real garments. The evaluation and comparison of virtual and real pressure results allows to study the possibilities of prediction and optimization of compression values of functional products using 3D virtual fitting technologies. Application of virtual fit technology in compression garments development process can ensure the particular pressure value in the certain zone of the functional garment and evaluate the change in compression properties as the body dimensions’ change
Evaluation of QR code geometric parameters and readability under tensile stress /
No full textModern labels based on QR code could be an attractive solution to provide information about garment origin, composition, repair, maintenance and disassembly through the whole product life cycle, reduce waste and promote sustainable resource use. QR code is cost-effective, easy to implement technology, however it also comes with some limitations. The challenges of label quality related to the durability and readability of the integrated QR code in the fabric may appear over time when the label is subjected to mechanical impacts. Earlier research aimed to evaluate the influence of different technologies (embroidery, sublimation, and heat transfer printing) on the quality and readability of QR code. It has proved that embroidery presents the biggest technical difficulties, but this technology has less limitations for fabric composition, heat sensitivity, etc. while compared with other used technologies. Additionally, embroidery conveys a sense of craftmanship, luxury and can also be as part of products design. This study focusses on changes in the geometrical parameters of the embroidered QR code during tensile tests, considering deformations in both the wales and courses directions of the interlock jersey fabric. The geometric distortion of the QR code is estimated based on image analysis. The readability of QR code depends mostly on the finder, timing and alignment patterns that are created within QR code. Previous study revealed that unmatching value percentage is reliable parameter to evaluate the readability of QR code and analyse geometric distortion of QR image elements. The chosen research and assessment approach may have wider applications, potentially extending to other small embroidered features beyond QR codes
Investigating the transformative potential of textile air distribution systems for enhanced sustainability /
No full textThis study examines the potential of textile air distribution systems, highlighting their advantages over traditional sheet metal ducting in efficiency and maintenance. We introduce an experimental technical textile with advanced properties, including variable antistatic features achieved through innovative single-finishing techniques. A comprehensive life cycle assessment indicates that gradual enhancements using cutting-edge textile technologies can significantly improve sustainability parameters
DaGAM-Trans: dual graph attention module-based transformer for offline signature forgery detection /
No full textObjective: The detection of signature forgeries is a critical challenge in domains such as forensic investigations, financial security, and biometric authentication. This study aims to improve the offline detection of signature forgery, especially in cases of skilled forgeries where traditional methods relying on handcrafted features and statistical models often fail to distinguish between genuine and forged signatures. Material and Methods: To address these limitations, we propose DaGAM-Trans, a Dual Attention Graph Attention Module-based Transformer model that integrates Graph Attention Networks (GAT) with a Transformer backbone. The Transformer architecture plays a key role in modeling global contextual dependencies across the entire signature image, enabling the system to capture long-range structural information crucial for distinguishing genuine signatures from skilled forgeries. The architecture comprises a Graph Attention Module (GAM) to capture spatial dependencies using multi-head graph attention and graph convolution layers, and a Channel Attention Module (CAM) to amplify discriminative features and suppress irrelevant information. Additionally, a Graph Multi-Scale Adaptive Pooling (GMSAPool) layer is introduced to optimize feature aggregation by preserving salient details and reducing redundancy. The model is evaluated on four publicly available signature datasets: SigComp2011, BHSig260, CEDAR, and UTSig, within a cross-language verification setting. Results: DaGAM-Trans demonstrates superior performance across all datasets. Notably, it achieves 100% accuracy on the CEDAR dataset, with a False Acceptance Rate (FAR) as low as 0.001 and an Equal Error Rate (EER) reduced to 9.5%. Comparative experiments confirm that DaGAM-Trans outperforms existing state-of-the-art methods in terms of accuracy, FAR, FRR, and EER. Visualization through attention maps further validates the model's capacity to localize and highlight discriminative regions in signature images. Conclusion: The proposed DaGAM-Trans model effectively enhances offline signature forgery detection by leveraging dual attention mechanisms and adaptive graph-based pooling. Its outstanding performance, especially in reducing error rates and handling cross-linguistic signature variability, demonstrates its robustness and applicability for real-world biometric and forensic authentication tasks
Enabling learning by students when facing radically new information in business and management studies /
No full textThe aim of this paper is to substantiate the process of enabling learning by students when facing radically new information in business and management studies. Starting from the introduction and the research methodology, the paper follows by referring to Piaget’s theory, which presents the accommodation process by explaining the formation of new thinking structures necessary for learning radical new information. The Seven steps educational process (SESEP) is then presented by using secondary analysis. The principles of the SESEP model were described by the authors in their previous study while researching the development of education students’ competence in using potential learning environments. Secondary analysis allows for a concentrated discussion, revealing how the SESEP enables students (who are studying for a master’s degree in education) to learn when they are facing radically new information. The results of interviews with experts (experienced teachers in business and management studies) are presented, which show the possibility to transfer the SESEP into a model for enabling learning by students when facing radically new information (ENARNI) in business and management studies. The discussion of the results leads to a more detailed justification of the model