| | SLO | ENG | Cookies and privacy

Bigger font | Smaller font

Search the digital library catalog Help

Query: search in
search in
search in
search in
* old and bologna study programme

Options:
  Reset


1 - 10 / 44
First pagePrevious page12345Next pageLast page
1.
2.
3.
Vpliv izdelovalnih parametrov na lastnosti izdelkov iz Ti-6Al-4V, narejenih s selektivnim laserskim taljenjem in plastenje površine z bioaktivnim polimerom
Snehashis Pal, 2019, doctoral dissertation

Abstract: Technological parameters included in energy density (ED) are the more powerful tools in selective laser melting (SLM) technology which can be used in the time of fabrication to regulate chemical, metallurgical, and mechanical properties of a product. The volumetric Energy Density (ED) depends on the energy input employed by the laser power, scanning speed, hatch spacing, and the layer thickness. Density, microstructure, surface morphology, dimension accuracy, strength and porosity including the number of pores, place of the pore, size of a pore shape of a pore, inclusions of pores of an SLM product depends on the processing parameters. As the powder material fusion process is done by track by track and layer by layer, the architecture of the microstructure in a product is oriented as the direction of building up too. The research has emphasized on metallurgical properties, tensile properties, and producing the non-porous products from Ti-6Al-4V alloy powder and surface modification using bioactive polymer for orthopedic application. The research has followed four steps to study the metallurgical properties and finding out the combinations of technological parameters in producing non-porous products. The purpose of the first step of the study was to examine the effects of ED on the product properties and to obtain an optimum ED as well as the optimal range of scanning speed. The second step of the study has focused on the influences of laser power. The third step of the study has investigated the effect of amounts of track overlapping and hatch spacing. Almost a zero-porosity product has been able to produce by following these three steps of the ongoing research. The fourth step has studied the metallurgical properties emphasizing on re-melting of every layer. High-density products have been found in the fourth step where a small amount of very small sized pores are present as a result of keyhole effect and gaseous bubble entrapment mainly. Four buildup orientations have been selected for each ED in the first step of the study to examine the tensile properties of the products. The best buildup orientation has been seen in longitudinally vertical tensile specimens considering tensile properties. The tensile properties have also been studied in the second and third step of the study with best build up orientation of the tensile specimens. The alterations of metallurgical and tensile properties have also been investigated after heat-treatment of the specific samples. Dimensional accuracies were also invigilated on the cubic, and tensile specimens over the studies and consequently, inaccuracies have been noticed. The fifth step of the study has observed the pore properties, adhesion properties, the compressive strength of gelatin coating manufactured using unidirectional freezing and the freeze-drying process of three different gelatin concentrations on four different surfaced Ti-6Al-4V alloy substrates. The results indicate that the coating properties depend on the substrate’s surface texture as well as the concentration of gelatin. Above 80% of porosity, interconnected and well-aligned pores of 75-200 μm have been obtained which is required to stimulate bone ingrowth histologically.
Keywords: selective laser melting, unidirectional freezing, fabricating parameters, porosity, microstructure, mechanical strength
Published: 01.04.2019; Views: 685; Downloads: 94
.pdf Full text (10,52 MB)

4.
5.
6.
Redukcijska barvila: konvencionalni postopek barvanja in ekološke alternative
Mojca Božič, Vanja Kokol, 2006, review article

Abstract: Članek obravnava redukcijska barvila. V uvodu sta podana pomen in uporabnost teh barvil, temu pa sledita opis konvencionalnega barvanja in opis samih barvil. Prikazana je ekotoksikološka problematika barvanja z redukcijskimi barvili in kot posledica tega razvoj novih alternativnih postopkov, kot so: tehnološki (Sistem pro VAT plus, Conmpress C-plus, Caledon SF fl postopek), elektrokemijski (indirektni z uporabo mediatorja, direktni in elektrokatalitično hidrogeniranje) in bio-postopki (zamenjava toksičnih reducentov z biorazgradljivim in encimski postopki). Podano je še pospeševanje samega procesa (barvanja) ob souporabi fizikalnih metod, kot sta ultrazvok in elektromagnetno polje.
Keywords: barvanje tekstilij, redukcijska barvila, elektrokemijsko barvanje, elektrokatalitično hidrogeniranje, encimi, ultrazvok, IR, elektromagnetno polje, vplivi na okolje
Published: 31.08.2017; Views: 497; Downloads: 64
.pdf Full text (505,01 KB)
This document has many files! More...

7.
Biotehnologija v tekstilnih procesih plemenitenja. 3. del, Encimsko plemenitenje tekstilnih vlaken
Vanja Kokol, Vera Golob, 2002, review article

Abstract: Članek obravnava današnjo uporabo encimov v industrijskih procesih tekstilnega plemenitenja ter ob njihovem intenzivnem znanstvenem razvoju kompleksno opozarja na obstoječe aplikativne probleme in cilje v prihodnje. Po razloženi strukturno - funkcionalni aktivnosti encimov, njihovem tehnološkem postopku pridobivanja in vlogi genetskega inženiringa so podane ekološke in ekonomske prednosti njihove industrijske uporabe. Sledi podrobnejši opis možnosti uporabe encimov v posameznih postopkih tekstilnega plemenitenja in njihov znanstveni razvoj. Pregled je usmerjen tako na posamezne postopke v obdelavi naravnih vlaken kot tudi na prve poizkuse obdelave sintetičnih vlaken. Opisani so obstoječi problemi klasičnih plemenitilnih postopkov, od predobdelave, beljenja in barvanja do plemenitenja/apretiranja, ter predstavljene možnosti za vključitev encimskih postopkov. Podrobneje so opisana nova spoznanja na posameznih vlaknih in fazah encimskega plemenitenja; poseben poudarek je na razvoju novih encimov, primernih za njihovo obdelavo, novih encimskih postopkih, njihovih prednostih in slabostih, predvsem poškodbe vlaken in življenjska doba oz. ostala aktivnost encimov na tkanini. Podrobneje so opisani alternativni tehnološki postopki za doseganje posebnih končnih učinkov na površini tkanine. Po krajšem opisu razvoja novih, izjemno stabilnih encimov in njihovih prednostih je opozorjeno na obetavno uporabo biotehnologije v tekstilno obdelovalnih postopkih in perspektivo njihovega razvoja v prihodnje.
Keywords: tekstilno plemenitenje, biotehnologija, encimi, ekologija
Published: 31.08.2017; Views: 449; Downloads: 77
.pdf Full text (621,39 KB)
This document has many files! More...

8.
Biotehnologija v tekstilnih procesih plemenitenja. 2. del, Encimsko plemenitenje tekstilnih vlaken
Vanja Kokol, Vera Golob, 2002, review article

Abstract: Članek obravnava današnjo uporabo encimov v industrijskih procesih tekstilnega plemenitenja ter ob njihovem intenzivnem znanstvenem razvoju kompleksno opozarja na obstoječe aplikativne probleme in cilje v prihodnje. Po razloženi strukturno - funkcionalni aktivnosti encimov, njihovem tehnološkem postopku pridobivanja in vlogi genetskega inženiringa so podane ekološke in ekonomske prednosti njihove industrijske uporabe. Sledi podrobnejši opis možnosti uporabe encimov v posameznih postopkih tekstilnega plemenitenja in njihov znanstveni razvoj. Pregled je usmerjen tako na posamezne postopke v obdelavi naravnih vlaken kot tudi na prve poizkuse obdelave sintetičnih vlaken. Opisani so obstoječi problemi klasičnih plemenitilnih postopkov, od predobdelave, beljenja in barvanja do plemenitenja/apretiranja, ter predstavljene možnosti za vključitev encimskih postopkov. Podrobneje so opisana nova spoznanja na posameznih vlaknih in fazah encimskega plemenitenja; poseben poudarek je na razvoju novih encimov, primernih za njihovo obdelavo, novih encimskih postopkih, njihovih prednostih in slabostih, predvsem poškodbe vlaken in življenjska doba oz. ostala aktivnost encimov na tkanini. Podrobneje so opisani alternativni tehnološki postopki za doseganje posebnih končnih učinkov na površini tkanine. Po krajšem opisu razvoja novih, izjemno stabilnih encimov in njihovih prednostih je opozorjeno na obetavno uporabo biotehnologije v tekstilno obdelovalnih postopkih in perspektivo njihovega razvoja v prihodnje.
Keywords: tekstilstvo, plemenitenje, biotehnologija, encimi
Published: 31.08.2017; Views: 442; Downloads: 52
.pdf Full text (417,72 KB)
This document has many files! More...

9.
Biotehnologija v tekstilnih procesih plemenitenja. 1. del, Encimi, industrija in okolje
Vanja Kokol, Simona Teodorovič, Vera Golob, 2002, review article

Abstract: Članek obravnava današnjo uporabo encimov v industrijskih procesih tekstilnega plemenitenja ter ob njihovem intenzivnem znanstvenem razvoju kompleksno opozarja na obstoječe aplikativne probleme in cilje v prihodnje. Po razloženi strukturno - funkcionalni aktivnosti encimov, njihovem tehnološkem postopku pridobivanja in vlogi genetskega inženiringa so podane ekološke in ekonomske prednosti njihove industrijske uporabe. Sledi podrobnejši opis možnosti uporabe encimov v posameznih postopkih tekstilnega plemenitenja in njihov znanstveni razvoj. Pregled je usmerjen tako na posamezne postopke v obdelavi naravnih vlaken kot tudi na prve poizkuse obdelave sintetičnih vlaken. Opisani so obstoječi problemi klasičnih plemenitilnih postopkov, od predobdelave, beljenja in barvanja do plemenitenja/apretiranja, ter predstavljene možnosti za vključitev encimskih postopkov Podrobneje so opisana nova spoznanja na posameznih vlaknih in fazah encimskega plemenitenja; poseben poudarek je na razvoju novih encimov, primernih za njihovo obdelavo, novih encimskih postopkih, njihovih prednostih in slabostih, predvsem poškodbe vlaken in življenjska doba oz. ostala aktivnost encimov na tkanini. Podrobneje so opisani alternativni tehnološki postopki za doseganje posebnih končnih učinkov na površini tkanine. Po krajšem opisu razvoja novih, izjemno stabilnih encimov in njihovih prednostih je opozorjeno na obetavno uporabo biotehnologije v tekstilno obdelovalnih postopkih in perspektivo njihovega razvoja v prihodnje.
Keywords: tekstilna industrija, plemenitenje tekstilij, encimi, biotehnologija, ekologija
Published: 30.08.2017; Views: 614; Downloads: 70
.pdf Full text (769,16 KB)
This document has many files! More...

10.
Effect of peptides' binding on the antimicrobial activity and biocompatibility of ‎protein-based substrates ‎
Maja Kaisersberger Vincek, 2017, doctoral dissertation

Abstract: This work reveals the effect of coupling approach (chemical by using carbodiimide chemistry ‎and grafting-to vs. grafting-from synthesis routes, and enzymatic by using transglutaminase) ‎of a hydrophilic ε-poly-L-lysine (εPL) and an amphiphilic oligo-acyl-lysyl (OAK) derivative (K-7α12-OH) to wool fibers and gelatine (GEL) macromolecules, respectively, and substrates ‎antibacterial activity against Gram-negative E. coli and Gram-positive S. aureus bacteria ‎after 1–24 h of exposure, as well as their cytotoxicity. Different spectroscopic (ultraviolet-‎visible, infrared, fluorescence and electron paramagnetic resonance) and separation ‎techniques (size-exclusion chromatography and capillary zone electrophoresis) as well as ‎zeta potential and potentiometric titration analysis, were performed to confirm the covalent ‎coupling of εPL/OAK, and to determine the amount and orientation of its immobilisation.‎ The highest and kinetically the fastest level of bacterial reduction was achieved with ‎wool/GEL functionalised with εPL/OAK by chemical grafting-to approach. This effect ‎correlated with both the highest grafting yield and conformationally the highly-flexible ‎(brush-like) orientation linkage of εPL/OAK, implicating on the highest amount of accessible ‎amino groups interacting with bacterial membrane. However, OAK`s amphipathic structure, ‎the cationic charge and the hydrophobic moieties, resulted to relatively high reduction of S. ‎aureus for grafting-from and the enzymatic coupling approaches using OAK-functionalised ‎GEL. ‎ The εPL/OAK-functionalised GEL did not induce toxicity in human osteoblast cells, even at ‎‎~25-fold higher concentration than bacterial minimum inhibitory (MIC) concentration of ‎εPL/OAK, supporting their potential usage in biomedical applications.‎ It was also shown that non-ionic surfactant adsorbs strongly onto the wool surface during ‎the process of washing, thereby blocking the functional sites of immobilized εPL and ‎decreases its antibacterial efficiency. ‎ ‎
Keywords: wool, gelatine, antimicrobial peptides, ε-poly-L-lysine, oligo-acyl-lysyl, grafting chemistry, ‎grafting approach, peptide orientation, antibacterial activity, cytotoxicity‎
Published: 17.08.2017; Views: 913; Downloads: 88
.pdf Full text (3,98 MB)

Search done in 0.28 sec.
Back to top
Logos of partners University of Maribor University of Ljubljana University of Primorska University of Nova Gorica