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Amino- and ionic liquid-functionalised nanocrystalline ZnO via silane anchoring - an antimicrobial synergy
Vasko Jovanovski, Matejka Podlogar, Marjeta Čepin, Zorica Crnjak Orel, 2015

Abstract: Temperature has critical impact on food quality and safety within food supply chain, therefore, food should be kept at the defined storage temperature range. Final consumer should be assured when buying food about actual temperature and thermal history of the selected food product and this is why it should be indicated on the packed or prepacked item. The chromogenic temperature indicator for cold food chain was prepared from suitable active material packed in the properly structured holder. When temperature rises above the defined storage temperature, the active material changes colour and physical state (solid/liquid). Simultaneously, special packaging structure enables irreversible recording of the time exposed to the elevated temperature. The active material was made of thermochromic composite, consisting of dye, developer and solvent. It changes colour at its melting point, being coloured below and discoloured above it. The temperature is called activation temperature of the composite. Its value was adjusted by appropriate solvent and additives used for preparation of the composite, to reach the desired value. The temperature dependent colour change of the composite was determined by colorimetric measurements. The conditions for best observation of the change by naked eye were also examined. The structure of the active material’s holder was analyzed for best displaying of the time spend at high temperature (above the activation temperature). Functioning of the indicator was examined with growth of pathogens as a function of migration of the active material at temperature above the required storage temperature of the food. It was found out that the described chromogenic temperature indicator for cold food chain shows the thermal history of food storage by colour-, phase- and migration changes of the active composite material and consequently would be reliable as indicator in cold food chain to indicate temperature abuse and would disclose potential growth of psychrophilic microorganisms.
Keywords: Chromogenic temperature indicator, Food cold chain, Food quality and safety, Temperature control, Thermal history
DiRROS - Published: 16.12.2014; Views: 5381; Downloads: 745
URL Fulltext (0,00 KB)

The effects of habitat structure on red deer (Cervus elaphus) body mass
Klemen Jerina, 2007

Abstract: In most mammalian species, body mass is one of the key factors affecting an individual's fitness. It is therefore important to know the causes of its variability. The present paper analyses the influences of habitat structure and other environmental factors on body mass in red deer. The research is based on data sets concerning 3,920 culled red deer from the entire Slovenia, which are geo-referenced within a kilometer spatial accuracy, and on 28 spatially explicit raster layers of population density, habitat structure variables (e.g. topography, land use, forest structure, roads) and other environmental variables (e.g. air temperature, precipitation, supplementary feeding). After controlling for sex and age of the individual and its date of culling, body weight significantly differs between population areas, most likely as a result of genotype differences and genotype impact on the phenotype, and is also negatively dependent upon population density and the percentage of conifers and positively dependent upon annual mean air temperature and forest/meadow edge density. The stated environmental factors probably influence the achieved energy balance and, therefore, the body mass of red deer by conditioning the quantity and quality of food and energy expenditure of deer.
Keywords: red deer, body weight, habitat, evironmental factors, population density, forest edge, conifer, temperature, Slovenia
DiRROS - Published: 12.07.2017; Views: 3003; Downloads: 1311
.pdf Fulltext (713,95 KB)

Densification of wood
Andreja Kutnar, Milan Šernek, 2007

Abstract: The paper treats the processes involved in wood densification and provides a summary of the state-of-the-art, as presented in the literature, with regard to densification as achieved by compression, accompanied by some form of hydrothermal treatment. The viscoelastic nature of wood is discussed, togetherwith its thermal softening and typical stress-strain relationships. The properties of densified wood products depend, apart from processing parameters, on various anatomical features such as density, the percentage of late wood material, ray volume and the loading direction. The problems associated with wood stabilization after densification are also treated. Relevant examples of wood densification from fundamental research, and the results of applied studies significant for everyday practice, are presented. Aspecial focus is given on the process of viscoelastic thermal compression (VTC) of wood.
Keywords: wood, densification, softening, transverse compression, viscoelasticity, glass transition temperature
DiRROS - Published: 12.07.2017; Views: 2766; Downloads: 1226
.pdf Fulltext (476,08 KB)

Effects of various cutting treatments and topographic factors on microclimatic conditions in Dinaric fir-beech forests
Janez Kermavnar, Mitja Ferlan, Aleksander Marinšek, Klemen Eler, Andrej Kobler, Lado Kutnar, 2020

Abstract: Forest microclimate is strongly affected by local topography and management activities, as these directly alter overstory structure. In the present work we analysed the dependence of observed patterns of spatio-temporal microclimatic variations on topographic, canopy- and management-related factors. A forestry experiment was conducted in managed fir-beech forests in the Dinaric Mountains (Slovenia), which are characterized by rugged karstic terrain with numerous sinkholes. In 2012, cutting treatments representing a range in the intensity of overstory removal were performed: uncut controls (CON), 50% cut of stand growing stock (intermediate management intensity % IMI) and 100% cut (high management intensity % HMI) creating 0.4 ha canopy gaps. Fine-scale variation in aspect and slope and its effects on microclimate was assessed by comparing central, south-facing and north-facing within-sinkhole positions. We measured microclimatic variables (air temperature % T, relative humidity % RH) 0.5 m above the ground over three consecutive post-treatment growing seasons. Microclimatic variables showed an increase (T and vapour pressure deficit % VPD) or decrease (RH) with management intensity. Daily Tmax and VPDmax in HMI treatment were up to 5.9°C (on average 3.5°C) and up to 1.4 kPa (on average 0.6 kPa) higher than those in CON treatment, respectively, whereas daily RHmin was up to 22.7 (on average 13.0) percentage points lower. Regarding intra-seasonal patterns, microclimatic differences between treatments were largest during the summer. South-facing plots in the HMI treatment overall exhibited the most extreme conditions, i.e. the highest Tmax and lowest RHmin. Differences in microclimate between treatments were strongly modulated by canopy cover. The results also suggest that overstory removal increases topography-mediated variation in microclimate, as evidenced by significant differences in T, RH and VPD along the fine-scale topographic gradient within the created canopy gaps.
Keywords: tree cutting, air temperature, relative humidity, vapour pressure deficit, karst topography, canopy cover
DiRROS - Published: 08.10.2020; Views: 822; Downloads: 273
.pdf Fulltext (1,59 MB)

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