Wood is still the most widely used raw material for pulp and paper production in the world. However, due to the necessity to supply the paper industry with raw materials used in the extraction of ...cellulose fibres and the overexploitation of forests, new sources of primary pulp fibres had to be identified. The aim of this research is to highlight the important features of cereal crop residues and their utilization in the paper industry. As the chemical composition of plant materials is one of the most important indicators of how such materials can be used in paper production, the analysis of the chemical composition of straw with the highest grain production was performed. The straw, as a harvesting residue, is a fibre resource available from the annually renewable crops, produced abundantly in numerous regions all over the world. For the purpose of the research, wheat, triticale and barley straw were selected for the analysis. The analysis of carbohydrate, lignin and extraneous material (organic extractives and inorganic minerals) was performed in order to obtain the straw chemical composition. Based on the results of the chemical composition of all analysed straw, it was confi rmed that straw, as an agricultural by-product, is rich in cellulosic fibres and, therefore, a valuable raw material for the paper industry. Out of all analysed straw, based on the results of their chemical composition, triticale straw is considered potentially the best source of alternative cellulose fibres.
Today, the paper industry is faced with a global deficiency of raw wood materials, so alternative sources of virgin cellulose fibres are playing an important role in paper production. Agricultural ...countries produce large quantities of crop farming by-products such as straw, which is an interesting alternative raw material for cellulose fibres. Straw is used in many industries because of its numerous advantages: animal food industry, biofuel industry, construction industry and as artistic material. The potential use of straw production residues is of great importance in paper and printing industry. The focus of this research is on triticale straw, which was used as a non-wood fibre source for paper production. Namely, triticale straw was converted into semi-chemical pulp and was combined with recycled wood pulp in order to produce alternative laboratory papers. The usability of this kind of laboratory papers in printing industry was analysed based on line reproduction quality. This research evaluated and analysed line reproduction quality based on four line attributes: width, blurriness and raggedness. The results of this research proved that triticale pulp in laboratory papers has equal influence on line printing quality as the recycled wood pulp.
Jedno od najvećih pojednostavnjenja jednadžbe transfera pretpostavlja: upadno i raspršeno zračenje je savršeno difuzno, promatraju se samo dva suprotna smjera prijenosa svjetlosti, i intenzitet ...svjetlosti se mijenja samo duž jedne osi. Takvu aprokimaciju dva smjera prijenosa svjetlosi započeo je Schuster 1, a nastavili su Kubelka i Munk 2 1931. a model je dalje usavršio Kubelka 3-4. Kubelka i Munk su dali sažeti oblik i pristup s jasnim ciljem ka praktičnim metodama mjerenja. Ta metoda je bila brzo prihvaćena u papirnoj industriji 5-8 i danas ima široku piimjenu u mjerenju i procjeni obojenja, svjetline i opaciteta pri proizvodnji papira. Većina informacija u ovom članku preuzeta je iz referenca čiji se popis nalazi na kraju članka i koje je potrebno konzultirati za detaljniju analizu.
Kubelka i Munk dali su sažeti oblik i pristup s jasnim ciljem ka praktičnim metodama mjerenja. Njihova metoda je bila brzo prihvaćena u papirnoj industriji i danas ima široku primjenu u mjerenju i ...procjeni obojenja, svjetline i opaciteta pri proizvodnji papira. Unatoč tome navedena metoda posjeduje neke nedostatke i drugi dio članka će pokriti sustave na koje se ne može tako kvalitetno primijeniti (otisnuti i reciklirani papir). Također će biti riječi i o numeričkim modelima (simulacije putanja pojedinačnih fotona) koji se koriste kao nadopuna rezultatima dobivenima K-M metodom. Najčešće korišteni su Monte Carlo simulacijski modeli, GRACE i DORT. Većina informacija u ovom članku preuzeta je iz referenca čiji se popis nalazi na kraju članka i koje je potrebno konzultirati za detaljniju analizu.
This research observes changes in the properties of commercially available hemp office papers exposed to photo-oxidation for artificial aging. In order to accelerate the changes that naturally occur ...in paper, photo-oxidation was performed using a Xenon light source. The electromagnetic radiation was administered in doses of 550?W/m2 over 24 hours with a temperature of 60°C. Three types of hemp office papers that differ in chemical composition and manufacturing process were used as samples. The strength properties (tensile index, elongation at break, tear index), surface properties (Bendtsen roughness, Bekk smoothness), pH of paper extracts, and optical properties were observed. The listed properties of artificially aged samples were compared to those of unaged commercial paper samples. The results show that, after only 24 hours, accelerated aging with a Xenon arc lamp affects all observed paper properties. For all analyzed office papers, the values of the tensile index, Bekk smoothness, and pH of paper extracts decreased, while the values of elongation break, tear index, and Bendtsen roughness increased due accelerated aging. Regarding the CIE L*a*b* color space value, lightness (L*) generally decreased after the aging treatment, and all paper samples became less reddish (a* decreased) and more yellow (b* increased). The obtained results of this research reveal that pulp with hemp fibers can produce higher-quality office paper that is more stable against light and temperature influences than those made with post-consumer fibers. However, to increase the durability of manufactured paper, hemp fibers must be bleached.
Paper performance qualities strongly depend on the origin of cellulose fibers. Awareness of environmental issues and sustainable development has led to the increase in the use of recycled printing ...papers. Recovered fibers are often used as a substitute for virgin wood fibers in the production of certain types of papers. As recovered fibers cannot provide the same quality level of paper products as virgin wood fibers, alternative sources of virgin cellulose fibers need to be identified. The aim of this research was to analyze the printability of laboratory papers made of different contents of straw pulp. Therefore, the printing papers were formed using straw pulp of three different cereal species (wheat, barley, and triticale) and mixing them with recycled newsprint in different weight ratios. The printability of these laboratory papers was analyzed by classifying dot reproduction quality based on four dot reproduction attributes. Printed dot reproduction greatly affects the quality of reproduction in graphic products, as dots are the most important element in multi-color reproduction of texts and images. It was confirmed that laboratory papers containing straw pulp provide the same or even better dot reproduction quality than laboratory control papers formed only of recycled newsprint.
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This paper describes the improved removal of impurities (coating, ink/toner) from offset prints produced by digital printing of two-side coated paper. The substrates were printed by conventional and ...digital offset processes. Based on image analysis results it was established that deinking flotation is an inefficient method for ink particle removal from digital offset printed paper, but it is efficient for ink removal from conventional offset printed paper. On the other hand, pre-treatment with hydrogen peroxide solution gives better results for ink particle removal from digital offset prints than from conventional offset prints. Optimal parameters for hydrogen peroxide pre-treatment for both offset prints were chosen based on unprinted substrate mass loss results in the preliminary investigation. These results showed that hydrogen peroxide pre-treatment is more successful at removal of impurities in comparison with flotation deinking without pre-treatment.
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One of the greatest simplifications of the transfer equation is where all incident and scattered light is assumed to be perfectly diffuse, only two opposite directions of light transport are ...considered, and the light intensity is assumed to vary along one axis only. Such two-flux approximations have been presented by many authors, starting with a paper by Schuster 1. One of the most famous two-flux approximations is the approximation presented by Kubelka and Munk 2 in 1931 and further developed by Kubelka 3,4. Kubelka and Munk gave a comprehensive formulation and a treatment with a clear aim towards practical methods of measurement. It was quickly adapted for use by the papermaking industry 5-8 and has now been in widespread use for decades in the measurement and prediction of colour, brightness and opacity of paper sheets. Most of the information reported here is taken from the references cited at the end of the article which should be consulted for a more in-depth study.Original Abstract: Jedno od najvecih pojednostavnjenja jednadzbe transfera pretpostavlja: upadno i rasprseno zracenje je savrseno difuzno, promatraju se samo dva suprotna smjera prijenosa svjetlosti, i intenzitet svjetlosti se mijenja samo duz jedne osi. Takvu aproksimaciju dva smjera prijenosa svjetlosti zapoceo je Schuster 1, a nastavili su Kubelka i Munk 2 1931. a model je dalje usavrsio Kubelka 3-4. Kubelka i Munk su dali sazeti oblik i pristup s jasnim ciljem ka prakticnim metodama mjerenja. Ta metoda je bila brzo prihvacena u papirnoj industriji 5-8 i danas ima siroku primjenu u mjerenju i procjeni obojenja, svjetline i opaciteta pri proizvodnji papira. Vecina informacija u ovom clanku preuzeta je iz referenca ciji se popis nalazi na kraju clanka i koje je potrebno konzultirati za detaljniju analizu.
Drvo je još uvijek najčešća sirovina za proizvodnju celuloze i papira u svijetu. Međutim, s obzirom na količinu sirovine za izdvajanje celuloznih vlakanaca potrebnih papirnoj industriji te na ...prekomjernu eksploataciju šuma, nužno je pronaći nove izvore primarnih celuloznih vlakanca. Cilj ovog istraživanja bio je istaknuti važnost slame koja je kao poljoprivredni ostatak prikladna sirovina za industriju papira. Kako je kemijski sastav biljnog materijala jedan od najvažnijih razloga njegove upotrebe u proizvodnji papira, određen je kemijski sastav slame žitarica s najvećim doprinosom zrna. Slama, kao ostatak nakon žetve, godišnje je obnovljiv izvor vlakanaca u mnogim regijama diljem svijeta proizvodi u izobilju. Za ovo je istraživanje izabrana slama pšenice, pšenoraži i ječma. Obavljena je kvantitativna analiza ugljikohidrata, lignina i ekstraktivnih tvari (organski ekstrakti i anorganski minerali) kako bi se odredio kemijski sastav slame žitarica. Na temelju kemijskog sastava svih analiziranih slama potvrđeno je kako je slama kao poljoprivredni nusproizvod bogat izvor celuloznih vlakanaca, a time i vrijedna sirovina za industriju papira. Od svih analiziranih uzoraka slama pšenoraži svojim se kemijskim sastavom nametnula kao najveći potencijalni izvor alternativnih celuloznih vlakanaca.
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