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Abstract: Since the non-image-forming (NIF) effect of daylight on the human circadian system is widely accepted, adequate exposure to daylight is now considered one of the elements of a healthy life. In urban environment, one of the prerequisites for adequately lit indoor spaces is the amount and quality of daylight reaching the window, which is highly dependent on the characteristics of the urban environment. The aim of the study was to determine whether there are correlations between urban density (i.e., distance between buildings, building height), façade surface characteristics (i.e., colour and Window-to-Wall Ratios – WWR) and NIF potential of daylight. The study was conducted on a parametric geometric model of a street canyon covering a wide range of characteristics. Simulation results were interpreted using the Relative Melanopic Efficacy coefficient and Sky View Factor. The results indicate that the colour of the opposite façade can substantially impact the resulting NIF potential, especially for orange-red or blue hues. The results of the study show that this influence for building heights between 3 and 8 storeys becomes significant when the width of the urban canyon is less than 25 m and becomes substantially smaller at WWRs above 30 %.
Keywords: urban planning, daylight, non-image forming effects of light, circadian light, urban canyon, façade colour
Published in DKUM: 19.01.2024; Views: 415; Downloads: 35
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Abstract: Biological variation is omnipresent in nature. It contains useful information that is neglected by the usually applied statistical procedures. To extract this information special procedures have to be applied. Biological variation is seen in properties (e.g. size, colour, firmness), but the underlying issue is almost always to the variation in development or maturity in a batch of individuals generated by small scale environmental differences. The principles of assessing biological variation in batches of individuals are explained without putting emphasis on mathematical details. Obtained explained parts increase from about 60 to 80 % for the usual approach to 95 when the biological variation is taken into account. When technical variation or measuring error is small even 99 % can be achieved. The benefit of the presented technology is highlighted based on a number of already published studies covering the colour of apples during growth and storage and the firmness of cut tomatoes during storage.
Keywords: biological variation, biological shift factor, mixed effects nonlinear regression, indexed nonlinear regression, colour of apples, firmness of tomatoes
Published in DKUM: 13.07.2017; Views: 1250; Downloads: 402
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Abstract: The paper briefly describes a mathematical model of the colorant mixture colour sensitivity to concentration errors and the numerical estimates of the related quantities. Features of the theoretical model are illustrated with the results of a number of numerical experiments in which the optical data of a few basic dyes applied to textile fabric were used to predict the sensitivities of recipes for sets of target colours spaced regularly in the colour solid. The rest of the article deals with the question whether the predicted values of recipe colour sensitivity provide useful information about the repeatability of recipe colour. The results of a few groups of laboratory experiments involving the textile fabric dyeing with basic dyes have been analysed with this question in mind.
Keywords: textile dyeing, basic dyes, recipe colour, colour, color repeatability, colour sensitivity, concentration errors, mathematical model
Published in DKUM: 05.07.2017; Views: 1258; Downloads: 118
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Abstract: Colour and taste are important attributes of apple fruit quality that is generated during the fruit-growing period. Despite a plethora of studies dealing with this topic, the detailed information on how quality is generated is, however, still lacking. This is because traditionally, the obtained agro-morphological and biochemical data are analysed with empirical models using mean values of large samples, without taking the effects of biological variation into account, thus completely masking the spatio-temporal physiological mechanisms. To really understand quality, its generation during fruit growth needs to be monitored and modelled. When knowledge exists on the type and kinetics of the processes involved, the variation in properties can be described and taken into account by using so-called fundamental models, built on theoretical considerations. To understand the behaviour and the variation of colour and taste compounds, within or between individual fruits, and to assess their importance throughout the food supply chain, it is therefore important to understand the dynamics of these compounds during growth. The study consisted of (1) a preliminary experiment, aiming to determine the suitability of the semi-destructive biopsy sampling technique for in-vivo monitoring of certain metabolites during apple fruit development on a tree, (2) an experiment on spatial distribution, and (3) an experiment on temporal distribution of metabolites and colour in developing individual apple fruit. The experiment on spatial distribution was conducted to determine the effect of location on the accumulation of the individual quality components within apple fruit, and the parallel temporal experiment was conducted to monitor the dynamics and mechanisms of these components in apple fruit during on the tree development. Diameter and standard maturity indices of fruit flesh firmness, soluble solids content, starch degradation index, titratable acidity, and Streif maturity index were also determined, to obtain relations between individual quality components. Colour descriptors (L*, a* b*), individual sugars (fructose, sucrose, glucose), sorbitol, and individual organic acids (malic, citric, shikimic, fumaric) were monitored from 40 and 54 days before to 16 and 32 days after the optimum maturity for long term storage on individual apples of cv. ‘Gala’ and cv. ‘Pinova’. Data were analysed with classic empirical statistics as well as with non-linear indexed regression, based on process oriented models, which included biological variation between apples of the same batch. Frequently probelation and quantile regression were applied. The results of the preliminary experiment confirmed that the novel biopsy sampling technique is suitable for in-vivo monitoring of the spatio-temporal distribution of colour and individual taste components during on-tree apple fruit development. In the results from the experiment on spatial distribution, a sinusoidal distribution over locations at 70° above the fruit equator was observed for all the monitored quality components. Descriptor a* was highest at the blush, and b* and L* at the shaded side of the fruit. Citric acid preferentially accumulated at the shaded side of the fruit, whereas fructose in cv. ‘Gala’ tended to accumulate at the blush. Other metabolites were more or less equally distributed within fruit. The results of longitudinal monitoring reveal a sigmoidal increase of a*, an exponential increase of diameter and sugars, and an exponential decrease of organic acids over time. In both cultivars, large variations were observed between individual fruit for all the monitored quality components. When analysed with non-linear indexed regression, based on process-oriented models, and after the probelation combined with quantile regression, the explained parts of the majority of the monitored quality components were well above 90 %. The mechanism of colour development was the same for both cultivars. The biological shift factor for all metabolites and colour had roughly the same value within cultiv
Keywords: apple fruit, colour, models, organic acids, spatio-temporal monitoring, sugars
Published in DKUM: 19.12.2013; Views: 3040; Downloads: 307
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Abstract: The essential question of the paper "Can the predicted sensitivity to random and/or proportional dye concentration errors assist in selecting the most repeatable recipes?" was investigated using the laboratory dyeing of acrylic fabric with basic dyes. When the dye strength errors were not involved, the biggest scattering of the recipe colour in repeated dyeings was observed in the cases of light neutral target colours, where the predicted sensitivity to random concentration errors was the highest. For a few low-saturated targets, eight recipes with different predicted sensitivities to random errors were treated. In six cases out of the seven treated, those recipes less sensitive to random concentration errors generally performed better than the more sensitive ones, but the correlation was rather weak. For those cases whenthe dye strength errors were included, experiments were also carried out with several different recipes for a neutral medium-lightness target colour.
Keywords: colour, textile dyeing, computer aided reciping, recipe colour sensitivity
Published in DKUM: 01.06.2012; Views: 1964; Downloads: 37
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