Three higher hydrocarbon phase change materials (PCMs) with melting points of 25, 40 and 50 degrees C were microencapsulated by in situ polymerization of amino-aldehyde resins. Trimethylolmelamine (TMM) and hexamethoxymethylolmelamine (HMMM) were studied as amino-aldehyde pre-polymers for microcapsule wall formation, in combination with emulsifying/modifying agents based on styrene-malein anhydride copolymers (SMA) of different molecular weights and different styrene-maleic acid anhydride ratios. Microcapsule sizes, size distribution and wall permeability were analysed. A mathematical model was developed for comparing the mechanical resistance of different batches of microcapsules, produced at different TMM-SMA ratios. Larger microcapsules with thicker walls and larger pores (M(LAR)) expressed lower resistance to breakage than slightly smaller microcapsules with thinner walls and finer pore structure (M(SMA)). Mathematical data were confirmed by a smudging colouration test. Laboratory microencapsulation process parameters were optimized to obtain impermeable microcapsules with improved mechanical stability. The process was transferred into a 10l pilot reactor for two PCMs with melting points of 25 and 40 degrees C. Dry powder of microencapsulated PCMs was obtained by spray drying of aqueous microcapsule suspensions.

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Invasive alien plant species (IAPS) are one of the biggest challenges in European ecosystems, displacing local vegetation, destroying agricultural land, and causing billions of dollars of damage to the European economy every year. Many of them are removed daily and mainly burned. In this work, we investigated the possibilities of using plants as feedstock for paper production. Papers made from three invasive alien plants, i.e., Knotweed, Goldenrod, and Black locust, were studied and compared with commercial office paper. The study included testing of: (1) structural properties—basic physical properties, grammage, thickness, density and specific volume, moisture content, and ash content; (2) physical and dynamic mechanical properties—tensile strength, Clark stiffness, viscoelastic properties; (3) colorimetric properties of prints; (4) effect of UV light on ageing; and (5) study of cellulose fiber structure and morphology by microscopy. The results suggested that the paper produced can be used as commercial office paper, considering that the paper is slightly dyed. Such papers can also be used for special purposes that present a natural style and connection to nature. The papers produced can also be used for printing documents that are meant to be kept.

A method for identifying colors in urban environments using a digital camera was established. Color analysis of images was performed using the CIELAB color space. The color coordinates were used to produce a color chart of prevailing colors in the area, which was later used to design a textile pattern. Color samples were in good agreement with the perceived colors of the surroundings. Neutral colors in gray tones predominate in the majority of the city of Ljubljana, Slovenia; nevertheless, there are also bright colors, notably green, yellow, and beige. The method described is fast and reliable enough to identify colors in urban environments. However, the analysis of a large number of photographs is needed to ensure objective results. To obtain reliable results for measured color values, it is necessary to exactly define the conditions under which photographs were taken.

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Original scientific paper Image quality can be determined by using objective or subjective quality assessment methods. Objective methods are based on mathematical measures, such as PSNR, SSIM or RMSE and subjective testing is generally performed by asking the participants which of the given options they prefer or to give a quality score for the presented options. For each image quality evaluation, an image database is required. We developed a novel image database that consists of 30 images on which we applied some manipulations based on different quality parameters. First we conducted testing with the eye-tracking method: by showing images to test participants and measuring their eye movement, we received accurate information about how each of the image quality parameters affected the communication value of each image. The subjective quality assessment method we then employed involved the development of an application for crowdsourcing-based testing. Participants had to determine which of the images the best were. Finally, a correlation between both methods was determined.Keywords: crowdsourcing; eye movement; eye-tracking; image quality; photography; quality parameters Analiza pokreta očiju u određivanju parametara kvalitete slike u usporedbi sa subjektivnom procjenom kvalitete slike Izvorni znanstveni članak Kvaliteta slike može se odrediti primjenom objektivnih ili subjektivnih metoda za procjenu kvalitete. Objektivne se metode zasnivaju na matematičkim mjerama kao što su PSNR, SSIM ili RMSE dok se subjektivno testiranje općenito provodi ili postavljanjem pitanja sudionicima koju od datih opcija preferiraju ili traženjem da dadu ocjenu kvalitete za predložene opcije. Za procjenu kvalitete svake slike potrebna je baza podataka slike. Mi smo razvili novu bazu podataka koja se sastoji od 30 slika na kojima smo napravili određene manipulacije na temelju različitih parametara kvalitete. Najprije smo proveli testiranje metodom praćenja pogleda: pokazivanjem slika sudionicima ispitivanja i mjerenjem pokreta njihovih očiju dobili smo točne informacije o tome kako je svaki od parametara kvalitete slike utjecao na komunikacijsku vrijednost svake slike. Metoda subjektivne procjene kvalitete koju smo zatim primijenili uključila je razvoj aplikacije za ispitivanje zasnovano na masovnoj podršci. Sudionici su trebali odrediti koja od slika je najbolja. Konačno, određena je korelacija između obadvije metode.

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