Postharvest irradiation with blue light increases anthocyanin contents and quercetin glycosides in three apple cultivars.
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•Effects of blue-light irradiation versus control were ...generally cultivar dependent.•Irradiation with blue light increased anthocyanin content and PAL activity.•Anthocyanin composition of irradiated apples differed from naturally colored apples.•Blue light increased quercetin glycosides contents.•Blue-light is a promising tool to enhance apple color and nutritional quality.
The effects of postharvest blue-light irradiation on the accumulation of anthocyanins and other phenolic compounds, and on phenylalanine ammonia-lyase activities and color development in the skin was investigated in fruit of three apple cultivars (Malus domestica Borkh.). ‘Idared’, ‘Fuji’, and ‘Carjevič’ apples were harvested at the commercial maturity stage and irradiated or not with blue LEDs (peak wavelength 444 nm) at 8 °C for 7 days. Response to the irradiation was cultivar dependent. Anthocyanin accumulation was greatest in ‘Idared’ apples; however, the anthocyanins profile differed from that in the naturally colored apples. Twelve phenolic compounds were evaluated. Among these, chlorogenic acid and total flavonols increased in all cultivars after blue-light irradiation. Structure-specific responses of quercetin glycosides were detected in terms of the sugar moieties. Three out of six evaluated quercetin glycosides increased after irradiation, with the highest relative increase seen for quercetin 3-O-arabinopyranoside, followed by quercetin 3-O-galactoside and quercetin 3-O-glucoside. Contents of quercetin 3-O-arabinofuranoside, quercetin 3-O-rhamnoside and quercetin 3-O-xyloside were not affected by irradiation. The highest phenylalanine ammonia-lyase activity was seen for ‘Fuji’ apples after blue-light irradiation. Therefore, blue-light irradiation appears to be promising to enhance color and nutritional quality of apples.
•CCT value has a significant influence on our overall perception of the environment.•An approach has been developed that can effectively determine the CCT value from RGB images.•For estimation of CCT ...values from RGB images, a novel deep regression model was developed.•In the study, 191 RGB images and their corresponding CCT values were used to create the database.
Accurate measurement of correlated color temperature (CCT) which represents the color of light source is critical in photometry research. Current research shows that the value of CCT in environment has diverse and important effects on human perception and behaviour. Since we spend a large portion of our day indoors, these effects have a considerably greater impact on our daily lives than we think. For instance, the temperature perception of the environment or shape perceptions of students is related to CCT value in the environment. The value of CCT which is created by light sources in environment can be determined in a variety of ways in literature. CCT values of the environment can be measured precisely with spectroradiometers, which are special and relatively expensive measurement devices that aim to precisely measure radiance, luminance and chromaticity of light. Additionally, CCT values can be estimated with lower accuracy using various color space transformations and predefined models instead of spectroradiometer devices. In this study, an alternative approach to these two techniques for measuring CCT in the environment is proposed. CCT values of the environments were determined closer to spectroradiometer measurement results thanks to the deep regression model developed within the scope of this study using only RGB cameras. 191 different specially created RGB images and corresponding CCT values were taught to deep learning network structure for creating a regression model. The proposed approach performance was compared to alternative CCT calculation methods in literature using a variety of real-scene test images.
This study attempts to clarify the effect of canopy position on the physico-chemical parameters of apples cv. Braeburn. The experiments were carried out on fruit from the inner and outer part of the ...canopy in two growing seasons and at two harvest dates. Light measurements revealed that the average value of photo active radiation (PAR) for the inside and outside canopy amounted to 30.3 μmol/m2/s and 133.7 μmol/m2/s, respectively. Production year and canopy position significantly influenced ground color parameters a*, b*, C*, and h°, while the harvest date influenced all color parameters studied. For additional (red blush) coloration, the production year significantly influenced only the L* parameter, harvest date influenced all color parameters, and canopy position influenced L, a*, and C*. Only the fruits of the second harvest date showed more intense additional (red blush) coloration. The production year significantly affected fruit mass, firmness, total soluble solids (SSC), titratable acidity (TA), SSC/TA ratio, DPPH radical scavenging assay (AOP), total phenolic content (TPC), and total flavonoid content (TFC). The harvest date significantly influenced fruit mass, SSC, TA, SSC/TA, AOP, TPC, and TFC. The canopy position significantly influenced SSC, TA, AOP, TPC, and TFC. Regarding mineral content, the production year significantly affected the content of Fe, Ni, Cu, and Ca and the K/Ca ratio. The harvest date significantly affected Fe, Cu, Sr, K and K/Ca. The canopy position affected Fe, Ni, Zn, Sr, Ca, and K/Ca ratio, with a clear significant trend regarding the effect of canopy position only for Ca content (first and second year of the second harvest date) and K/Ca ratio (first year of both harvest dates). PCA analyses identified distinguishing features between apples, with differences defined specifically by AOP, TPC, TFC, Rb, Sr, Ca, and K/Ca on the PC 1 and Mn, Fe, Ni, Cu, and Zn on PC 2.
The improper illumination of cultural heritage buildings and monuments can be a source of enormous light pollution, which can have a major impact on the overall environment of the illuminated area. ...Such lighting can be the result of carelessness or a poorly designed lighting system. This paper presents one of the methodologies that can significantly reduce light pollution, especially spilt light out of building façades. The methodology is based on using luminaires with specially made shutters and an appropriate silhouette of the object. The shutters are designed with the help of photos of the object and the location’s sizes measured. The methodology was tested during the renovation of the lighting systems of different churches in Slovenia and is described using the example of the Church of St. Thomas near Ptuj, Slovenia (N 46°28.9554′, E 16°0.7416′). The results show that the methodology is effective and can significantly reduce light pollution that occurs when such buildings are incorrectly lit.
The aim of the research was to find out how proposed new CIE standard illuminant L would influence the measurement uncertainty of photometrical field measurements of luminance and illuminance. With ...help of data of 10 different photometers and 75 spectral power distributions (SPDs) of light sources a large number of spectral mismatch correction factors (SMCFs) were calculated and analyzed. Based on preliminary results, 10 different light sources were selected as possible calibration sources. For each SPD of considered light sources most suitable calibration source was found together with overall best calibration source which gives SMCFs closest to value 1 for all photometers and light sources. Results show that white LED with CCT close to 4000 K is the best suitable calibration source and its use would in average decrease the measurement uncertainty of field measurements of luminance or illuminance by up to 2 %. The decrease can be noticed at average as well as at very good instruments.
This paper presents a preliminary data analysis of vehicle speed on an urban road under different lighting levels. The speed limit on the road where the speed camera is located (near traffic lights ...and intersections, with speed bumps) is 50 km/h. The study shows that the vehicle speed was reduced by reducing the lighting level on the road. The lighting level was first reduced from 100 % luminance (road lighting standard is M4 (EN 12301), {L_{ave}} = 0.75\,{\text{cd/m}}^{{2}} ) to 80 % luminance {L_{ave}} = 0.60\,{\text{cd/}}{\mathrm{m}}^{{2}} and then further reduced to 60 % luminance {L_{ave}} = 0.45\,{\text{cd/m}}^{{2}} . After the reduction of luminance, the measurements also show the reduction of vehicle speed. The influence of illuminance level on vehicle speed decreases more after the first reduction from 100 % to 80 % (average speed decrease from 34.32 km/h to 32.85 km/h) than after the second step from 80 % to 60 % level (average speed decrease from 34.32 km/h to 32.85 km/h). There are some differences in the speed-illumination level relationship between different types of vehicles. The illumination level and speed of passenger cars, semi-trucks, trucks, and vans are all positively correlated, and the correlation coefficients R 2 are above 0.003, which are all statistically significant (p⩽0.005). The speed of a total of 3 059 449 vehicles was measured during this experiment. There were 75 % cars, 11 % vans, 9 % two-wheelers such as motorcycles or bicycles, 3 % trucks, and 2 % semi-trucks.
Artificial lighting is a basic need for human wellbeing and performance when there is no access to daylight. Large populations, mostly in rural areas, depend on traditional biomass-based lighting ...techniques whereas in developing countries with electricity supply mostly energy inefficient electric lighting is applied. Implementation of energy efficient and smart lighting products and systems could reduce the annually increasing energy demand and greenhouse gas emissions in developing countries. However, these relatively recent energy efficient and smart lighting solutions are not common in developing countries due to various barriers including a lack of awareness and information, a lack of qualified engineers, and a lack of experience in implementing, testing and maintaining energy efficient and smart lighting design.This article summarizes the education development activities carried out at six universities in Vietnam and Myanmar. In addition to education development, lighting labs were established, teachers and technical staff were adequately trained, and interaction and cooperation between higher education institutions and public bodies and industry were enforced.
This paper talks about the measurements of luminous flux of different light sources and the production of an experimental set up for the purpose of observing light phenomena in LEDs. With the help of ...measurements, an insight on how luminous flux usually fluctuates in the various types of lamps was obtained. For easy observation and study of temporal light artefacts in LEDs, such as flicker and stroboscopic effect, an experimental set up with an option to adjust the supply voltage signal was constructed. At the end, we also show some of the results of the visual perception of flicker.
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