1. Region-based approach for machining time improvement in robot surface finishingTomaž Pušnik, Aleš Hace, 2024, izvirni znanstveni članek Opis: Traditionally, in robotic surface finishing, the entire workpiece is processed at a uniform speed, predetermined by the operator, which does not account for variations in the machinability across different regions of the workpiece. This conventional approach often leads to inefficiencies, especially given the diverse geometrical characteristics of workpieces that could potentially allow for different machining speeds. Our study introduces a region-based approach, which improves surface finishing machining time by allowing variable speeds and directions tailored to each region’s specific characteristics. This method leverages a task-oriented strategy integrating robot kinematics and workpiece surface geometry, subdivided by the clustering algorithm. Subsequently, methods for optimization algorithms were developed to calculate each region’s optimal machining speeds and directions. The efficacy of this approach was validated through numerical results on two distinct workpieces, demonstrating significant improvements in machining times. The region-based approach yielded up to a 37% reduction in machining time compared to traditional single-direction machining. Further enhancements were achieved by optimizing the workpiece positioning, which, in our case, added up to an additional 16% improvement from the initial position. Validation processes were conducted to ensure the collaborative robot’s joint velocities remained within safe operational limits while executing the region-based surface finishing strategy.
Ključne besede: robot surface finishing, collaborative robot, region-based machining, workpiece optimization, clustering, task-oriented machining, machining time optimization
Objavljeno v DKUM: 25.11.2024; Ogledov: 0; Prenosov: 6
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2. Eco friendly functional finishes of polyester fabric using keratin from wool and feather wastesLidija Fras Zemljič, Maja Čolnik, Darinka Fakin, Tanja Pušić, Vanessa Wendy Bračko, Tjaša Kraševac Glaser, Mojca Škerget, 2024, izvirni znanstveni članek Opis: This research showcases the use of hydrothermally extracted solutions from poultry feathers and wool as ecofriendly and versatile textile finishes. These solutions, derived from waste biomass containing the keratin
biopolymer, were obtained through environmentally conscious hydrothermal degradation processes. Initially,
the study focused on analysing the chemical parameters and properties of both dialysed and non-dialysed solutions extracted from feathers and wool. The investigation tracked primarily the presence of keratin within these
solutions. Upon application to polyester textiles as the reference material, the presence of these solutions on the
fabric surface was confirmed successfully. A thorough physicochemical analysis of the treated textiles involved
various analytical techniques. These encompassed surface composition analysis via X-ray Photoelectron Spectroscopy (XPS) and Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR), assessment of wettability through Contact Angle measurements, determination of surface charge using surface zeta
potential, and examination of the thermal and flame-retardant properties via Differential Scanning Calorimetry
(DSC), Thermogravimetric Analysis (TGA), and calorimetric tests. In addition, the colour, UV radiation transmission and antioxidant activity were evaluated using standard tests.
The remarkable effects of the treatment have been observed in the exceptional antioxidative action, fire
resistance, UV protection and enhanced hydrophilicity of these innovative multifunctional textiles. This
approach holds significant implications across research, economics and society, enriching Material Science by
deepening the understanding of materials and their multifaceted properties. Moreover, it promotes resource
efficiency, opens new sustainable textile market prospects, and contributes to social impact by supporting
environmental sustainability, engaging communities and ensuring health and safety benefits.
Ključne besede: poultry feathers and wool, hydrothermal extraction, polyester, finishing, green, multifunctionality
Objavljeno v DKUM: 03.09.2024; Ogledov: 43; Prenosov: 13
Celotno besedilo (1,87 MB)
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3. Multivariate analysis and chemometric characterisation of textile wastewater streamsDarja Kavšek, Tina Jerič, Alenka Majcen Le Marechal, Simona Vajnhandl, Adriána Bednárová, Darinka Brodnjak-Vončina, 2013, izvirni znanstveni članek Opis: The aim of this work was to design a quick and reliable method for the evaluation and classification of wastewater streams into treatable and non-treatable effluents for reuse/recycling. Different chemometric methods were used for this purpose handling the enormous amount of data, and additionally to find any hidden information, which would increase our knowledge and improve the classification. The data obtained from the processes description, together with the analytical results of measured parameters' characterising the wastewater of a particular process, enabled us to build a fast-decision model for separating different textile wastewater outlets. Altogether 49 wastewater samples from the textile finishing company were analysed, and 19 different physical chemical measurements were performed for each of them. The resulting classification model was aimed at an automated decision about the choice of treatment technologies or a prediction about the reusability of wastewaters within any textile finishing or other company having similar characteristics of wastewater streams.
Ključne besede: textile finishing wastewater, chemometrics, multivariate data analysis, wastewater treatment
Objavljeno v DKUM: 10.07.2015; Ogledov: 1960; Prenosov: 80
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4. A novel metalloprotease from Bacillus cereus for protein fibre processingFernanda de Sousa, Suzana Jus, Anita Erbel, Vanja Kokol, Artur Cavaco-Paulo, Georg M. Gübitz, 2007, izvirni znanstveni članek Opis: A novel protease produced by Bacillus cereus grown on wool as carbon and nitrogen source was purified. B. cereus protease is a neutral metalloprotease with a molecular mass of 45.6 kDa. The optimum activity was at 45 °C and pH 7.0. The substrate specificity was assessed using oxidized insulin B-chain and synthetic peptide substrates. The cleavage of the insulin B-chain was determined to be Asn3, Leu6, His10-Leu11, Ala14, Glu21, after 12 h incubation. Among the peptide substrates, the enzyme did not exhibit activity towards ester substrates; with p-nitroanilide, the kinetic data indicate that aliphatic and aromatic amino acids were the preferred residues at the P1 position. For furylacryloyl peptides substrates, which are typical substrates for thermolysin, the enzyme exhibited high hydrolytic activity with a Km values of 0.858 and 2.363 mM for N-(3-[2-Furyl]acryloyl)-Ala-Phe amide and N-(3-[2-Furyl]acryloyl)-Gly-Leu amide, respectively. The purified protease hydrolysed proteins substrates such as azocasein, azocoll, keratin azure and wool.
Ključne besede: textile finishing, enzymatic modification, wool fibre, enzymes, Bacilus cereus, specificity, kinetics, metalloprotease
Objavljeno v DKUM: 01.06.2012; Ogledov: 2501; Prenosov: 103
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6. A model of surface roughness constitution in the metal cutting process applying tools with defined stereometryStanisĺaw Adamczak, Edward Miko, Franc Čuš, 2009, izvirni znanstveni članek Opis: The process of surface roughness formation is complex and dependent on numerous factors. The analysis of the latest reports on the subject shows that mathematical relationships used for determining surface irregularities after turning and milling are not complete or accurate enough and, therefore, need to be corrected. A new generalized mathematical model of roughness formation was developed for surfaces shaped with round-nose tools. The model provides us with a quantitative analysis of the effects of the tool representation, undeformed chip thickness, tool vibrations in relation to the workpiece, tool runout (for multicutter tools) and, indirectly, also tool wear. This model can be used to prepare separate models for most of the typical machining operations. Surface roughness is represented here by two parameters Ra and Rt. Simulations carried out for this model helped to develop nomograms which can be used for predicting and controlling the roughness Ra of surfaces sculptured by face milling.
Ključne besede: metal cutting, surface roughness, finishing, face milling
Objavljeno v DKUM: 31.05.2012; Ogledov: 2028; Prenosov: 37
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