Papers by Ivana Gudlin Schwarz
Polymers
The need for sustainable alternatives to conventional plastic mulches in agriculture has led to t... more The need for sustainable alternatives to conventional plastic mulches in agriculture has led to the development of various types of biodegradable mulches made from natural fibres and biopolymers to reduce environmental pollution and mitigate soil pollution caused by conventional plastic mulch usage. Degradation, impact on soil temperature and humidity, and weed suppression properties of needle-punched nonwoven mulches of different mass per unit area, made of jute, hemp, viscose, and PLA biopolymer, are investigated. Their biodegradation is determined by changes in the mulch properties (mass per unit area, thickness, air permeability, tensile properties, microscopic images, and FTIR analyses) during 300 days of exposure to the environmental conditions in the period from May 2022 to February 2023. The change in mass per unit area, thickness, air permeability, and tensile properties of nonwoven mulches did not show a tendency to degrade during exposure to environmental conditions. The ...
Ovaj izum odnosi se na mjerenje sila probijanja tekstilnih plosnih proizvoda razlicitim oblicima ... more Ovaj izum odnosi se na mjerenje sila probijanja tekstilnih plosnih proizvoda razlicitim oblicima elemenata za probijanje na dinamometru, a prema međunarodnoj klasifikaciji patenata (MKP) klasificiran je u podrucju G – Fizika, 01 – Mjerenje, testiranje. Primarni cilj izuma je mjerenje sila probijanja tekstilnih plosnih proizvoda razlicitim oblicima elemenata za probijanje na dinamometru. Svrha ovog izuma prilagoditi uvjete ispitivanja stvarnim uvjetima primjene tekstilnog plosnog proizvoda, gdje su prisutna sferna naprezanja, a time i probijanja, na ravnim, pregibnim i spojnim dijelovima (zaobljenim ili ostrim) ovisno o stvarnoj primjeni tekstilnog plosnog proizvoda. Sekundarni cilj je osigurati jednostavnu instalaciju dogradnog uređaja, kao i njegovo besprijekorno funkcioniranje, sa mogucom trenutnom izmjenom razlicitih elemenata za probijanje prilagođenih jedinstvenom prstenu koji je sastavni dio uređaja. Dodatni ciljevi i prednosti izuma dijelom ce biti prikazani u opisu koji slijedi, a dijelom ce se saznati kroz primjenu izuma. Uređaj za ispitivanje svojstava tekstilnih plosnih proizvoda na probijanje na dinamometru po ovom izumu obuhvaca mjerenje otpor materijala na sferna naprezanja razlicitim oblicima elementa za probijanje i to: • kružno - razlicitim promjerima kugle (u primjeni npr. autonavlake, pregibno mjesto na koljenima i laktovima i sl.), • u obliku trostrane prizme (x, y, z osi pod kutom 90°) - razlicitih dimenzija (u primjeni npr. uglovi na metalnim konstrukcijama koje prekrivaju tekstilni plosni proizvodi – autocerade, satori i tende i sl.) Novim nacinima probijanja, dobit ce se uvid u cvrstocu materijala u realnim uvjetima primjene, sto također podrazumijeva i spojna mjesta tekstilnih materijala, odnosno mjesta najvecih naprezanja koja su najcesce i najslabija mjesta na gotovom proizvodu u primjeni. Priprema uzoraka za mjerenje sila probijanja tekstilnih plosnih proizvoda razlicitim oblicima elemenata za probijanje vrsi se izvan dinamometra, na nacin izrezivanja u kružni oblik dimenzije koja odgovara unutarnjem promjeru prstena s dodatkom za ucvrscenje.
By using individual parts of garments for police uniforms greater stresses and abrasion occur, e.... more By using individual parts of garments for police uniforms greater stresses and abrasion occur, e.g. in the flexion position of extremities. Besides, the seam is present in several locations, and it is mostly a critical point that will loosen in case of stress. The paper describes the impact of the seam on mechanical fabric properties. Tests were made on samples of a fabric stitched with two stitch densities and two needle sizes. According to the results obtained it may be ascertained that mechanical fabric properties change as regards stitch density and needle size.
In order to make a fabric with satisfying properties for target use, it is necessary to choose ra... more In order to make a fabric with satisfying properties for target use, it is necessary to choose raw material and fabric construction. New raw materials for fabric manufacturing are mostly of chemical origin, and they often imitate natural fibers successfully. On account of several good properties and a cost-effective production, these fibers increasingly replace natural fibers. Man-made fibers also have bad properties that cannot be completely eliminated ; they include discomfort and sometimes allergic symptoms in contact with the body. For this reason textile raw materials of natural origin is better to use, especially for medical textiles and textile products for intimate clothing, for which, apart from cotton, wool, silk and linen, bamboo fiber, which has its future because of its good properties, is increasingly used. New technologies, for manufacturing woven fabrics, provide a higher- quality, more competitive and more cost- efficient final product. In the production of woven fabrics, fibers, yarns and spinning process, as well as weaving process, plays an essential role. In this paper, physical and mechanical properties of the bamboo and cotton yarn and the fabrics woven from these yarns will be investigated. Based on the obtained results a comparison analysis will be carried out. This procedure will provide an insight whether cotton, as the most widely used natural fiber, can be replaced by the bamboo fiber, and if so, in which application it has advantageous. Furthermore, a certain conclusion on the justifiable use of these yarns for fabric making will be drawn.
Dat je pregled razvoja tkalackih strojeva kroz povijest do danasnjih najnovijih dostignuca. Istra... more Dat je pregled razvoja tkalackih strojeva kroz povijest do danasnjih najnovijih dostignuca. Istražena su najnovija podrucja razvoja koja se temelje na racionalizaciji utroska energije, automatizaciji strojeva, smanjenju potrebe za ljudskim radom, optimizaciji procesa, vecoj sigurnosti na radnom mjestu, vecoj fleksibilnosti i pouzdanosti stroja te mogucem upravljanju procesom iz daljine. Prema tijeku razvoja tkalackih strojeva prezentiranih na izložbama ITMA od 1959. do 2011. godine utvrđen je kontinuirani porast utkivnog ucinka po vrstama tkalackih strojeva. Utvrđeno je da se ipak neki noviji sustavi tkanja ne razvijaju dalje, kao i neke faze rada u izradi tkanina. Razvoj žakarskih tkalackih strojeva bez užista danas predstavlja jednu od najvecih novina u proizvodnji tkanina, kao i elektronsko upravljanje s gornjim dijelom stroja. Tkalacki strojevi za specificnu namjenu, osobito za tehnicke tkanine, sve se vise razvijaju s visokom razinom fleksibilnosti u promjeni artikala. Povecanje brzine tkalackih strojeva nije prioritet, veci naglasak daje se kvaliteti izrade i fleksibilnosti strojeva sto potvrđuje novi tkalacki stroj tt. Smit textile s jednom utkivnom sipkom.
Tekstil : časopis za tekstilnu tehnologiju i konfekciju, 2010
Textile Research Journal, Jul 22, 2022
The properties of cotton yarn which will be used as the warp were investigated before the weaving... more The properties of cotton yarn which will be used as the warp were investigated before the weaving process. The results of the breaking forces served to make an empirical and approximated diagram of the normal distribution. Yarn tests were performed by yarn passing through a weaving process simulator with electronic force measurement, speed, and the number of wefts. The number of breaks was registered during the yarn test. Measurements were performed simulating different conditions of the weaving process (change in reed density, higher dynamic tensile forces, lower dynamic tensile forces, and shed height changes). Data computer processing gave approximate diagrams of dynamic forces normal distribution under the test conditions, which do not show significance according to the χ2-test. By pairing a diagram of the breaking force and a diagram of one of the conditions in the weaving process, shown in the same line of forces, their intersection or surfaces overlap is expressed. Based on the integration of the intersection area of the breaking forces approximated diagrams and dynamic forces in the weaving process, the value of the intersection area according to the test conditions was obtained. A high degree of correlation was found by correlating the actual number of thread breaks registered at the time of testing and the intersection of areas for the corresponding condition. This makes it possible to predict the number of breaks in the warp threads during the weaving process if the yarn characteristics and the weaving conditions are known.
Tkanine za zastitnu odjecu koja se koristi na radnim mjestima gdje opasnost od elekrostatickog na... more Tkanine za zastitnu odjecu koja se koristi na radnim mjestima gdje opasnost od elekrostatickog naboja zahtijeva posebna svojstva. Osim ugodnosti pri nosenju izrazito je važno da radno odijelo stiti radnika od opasnosti elektricnih udara i nagomilavanje statickog elektriciteta. Istražene su 4 vrste tkanina u mjesavini 50% pamuka i 50% poliestera (PES) s manjim udjelima ugljikovih bikomponentnih vlakana (ugljik – polimer u razlicitim položajima i oblicima, te razlicito upredene s temeljnom pređom i razlicito raspoređene u tkanini). Prema dobivenim rezultatima može se utvrditi da nacin ispredanja bikomponentnih vlakana (ugljikovo vlakno + polimer) i položaja niti u tkanini (osnova, potka) znatno ovise o pojavi elektrostatickog naboja. Najmanji povrsinski otpor i izrazito najveci vertikalni otpor imala je tkanina s bikomponentnim ugljikovim vlaknom u jezgri upreden s dvije niti u mjesavini pamuka i PES. Ostale tkanine s ugljikovim bikomponentnim vlaknima koja su imala polimer u jezgri a ugljik u omotacu, istim ili slicnim poprecnim presjekom, upredene s jednom niti u mjesavini pamuka i PES, imale su slicna ponasanja, bez obzira na njihov kolicinski udjel u tkanini.
Autex Research Journal, Sep 1, 2018
During cutting process, cutting parts are laid in the fabric warp direction, that is, joint place... more During cutting process, cutting parts are laid in the fabric warp direction, that is, joint places of cutting parts are directed specifically to the warp direction. The abovementioned stresses are, therefore, present in the fabric weft direction, which is taken into consideration in preparation of samples to implement the testing for the purpose of solving this issue.
Polymers
Woven fabrics are widely used for thermal protection due to their porosity, which provides therma... more Woven fabrics are widely used for thermal protection due to their porosity, which provides thermal insulation and breathability. This research focuses on investigating the influential parameters in the thermal protective properties of layer interchanging double cloth, including the woven structure and varying yarn fineness. The properties affecting the protective properties and comfort of multilayered woven fabrics include the fabric thickness, fabric porosity, and air permeability. Darcy’s law is applicable for determining the effective air permeability of woven fabrics. By understanding and controlling fabric porosity, it becomes possible to develop thermal protective clothing that combines improved comfort, cost-efficiency, and effectiveness. This study represents a novel approach for the clarification of airflow permeability behavior in complex structures of elastic multilayer woven fabrics using Darcy’s law. This innovative approach expands the understanding of permeability in ...
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Papers by Ivana Gudlin Schwarz