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Objective: The present study was conducted during the agricultural year 2021-2022 with the aim of investigating the effect of planting date and shading on yield and some quantitative and qualitative characteristics of ginger using a split plot design with three replications at the research farm of the Aboureihan Campus, located in the Pakdasht region of Tehran province. Methods: In this study, the light level was controlled at four levels (no shading [full light], shading from August 7 until harvesting [light-shade], shading until August 6 [shade-light], and shading thoughout the growth period [full shading]) as the main factor and the secondary factor comprised the planting date at three levels (April 20, May 10, and May 31). Results: The results indicted that applying full shading initially, and then transitioning to the shade-light treatment along with planting ginger on the 20th of April, had the most significant impact on increasing all the examined traits, including yield components, yield, and the percentage of essential oil in ginger rhizomes. The two mentioned treatments (full shading and shade-light) led to an approximately 29% increase in the number of rhizomes in ginger plants compared to both the full light treatment and the light-shading treatment. On the other hand, the highest ginger essential oil percentage (1.76%) was obtained in plants planted on the 20th of April, which was approximately 25% higher when compared to the essential oil percentage of plants planted on the 31st of May. Conclusion: Implementing shading treatment on the planting date of April 20 could be a promising method for significantly increasing both the quantitative and qualitative yield of ginger under similar climatic conditions. [ABSTRACT FROM AUTHOR]

Background and Objectives: Light is an essential factor for growth and development in agricultural production. Vertical agriculture has been increasingly developed to produce leafy vegetables and herbs. High light consumption is the most important obstacle in the development of vertical farming system. Basil (Ocimum basilicum L.) is one of the most popular leafy vegetables and is suitable for growing in plant factories. Therefore, the aim of the present study was to reveal the yield and dry matter production response of basil to add far-red light to the photosynthetic active spectrum, and finally to investigate the interaction of far-red light and daily light integral (DLI) on growth, morphology and light use efficiency in basil. Materials and Methods: The research was performed in a split plot experiment based on a randomized complete block design. Treatments included daily light integral (DLI) at two levels of 6.4 and 10.8 (mol m -2 d -1 ), and far-red light at three levels of 0, 5 and 20% based on the light recipe of the LEDs DLI. The measured traits included morphological traits (fresh and dry weight of leaves, stems and plants, plant height and leaf area), growth (specific leaf area (SLA), and partitioning to leaves), and determining the efficiency of light and radiation use efficiency. Results: The results showed that the plant fresh and dry weight increased by far-red light at the level of 20% in high DLI conditions (10.8), which was due to the increase in stem fresh and dry weight. As a result, the partitioning to leaves decreased slightly, although it was not statistically significant. Similar to high DLI conditions, the plant fresh and dry weight increased with the addition of far-red light (5 and 20%) at low DLI conditions (6.4), but this increase was due to the increase in leaves fresh and dry weight, and eventually led to the more partitioning to leaves. SLA in plants grown in low DLI decreased significantly by decreasing the phytochrome stationary state (PSS) as a result of adding far-red light from 0.88 to 0.82, which was due to the increase in leaves dry matter. In this regard, in plants grown at high DLI, with decreasing the PSS as a result of adding far-red light from 0.88 to 0.85, the SLA did not change.Conclusion: In general, the response of shade avoidance syndrome (SAS) seems to be more associated with increased stem height when plants grown under high DLI, and is more associated with increased leaf area and stem height when plants grown under low DLI and high levels of far-red light. [ABSTRACT FROM AUTHOR]

In order to commercial productivity of microalgae that have a high potential for lipid production, the effort is to increase the cellular lipid content. This should be a smart considering based on various uses that are intended for this lipid increase. In other words, approaches to increase the targeted fatty acids while maintaining the final biomass are more important. The aim of this study is to investigate the changes in fatty acid composition in Nannochloropsis oculata microalgae under physicochemical stresses (light intensity and salinity). In this regard, the growth rate, the amount of chlorophyll and carotenoid, the approximate analysis and the profile of fatty acid changes of marine microalgae N. oculata under two mutual stresses of salinity (15, 25 and 40 g/l) and light intensity (Lux 1500 and Lux 10000) which at the end of the phase Logarithms were applied are examined. The results showed that according to the application of stresses after the completion of growth, there was no significant difference in the growth rate in different treatments (P>0.05). Also, despite the fact that the highest amount of total lipid was obtained under the salinity treatment of 40 g/l and the light intensity of Lux 1500, the highest amount of saturated fatty acids (SFA) was obtained under the treatment of salinity of 15 g/l and the light intensity of 10000 Lux, the highest amount of monounsaturated fatty acids (MUFA) under 25 g/l treatment and 10000 Lux light intensity and the highest amount of polyunsaturated fatty acids (PUFA) under 15 g/l treatment and 10000 Lux light intensity were obtained after 4 days of stress. Considering the effectiveness of fatty acid compounds from different kinds of physical and chemical stresses, in N. oculata microalgae, by controlling the cultivation conditions, the maximum amount of desired fatty acids can be achieved in accordance with the desired goals. [ABSTRACT FROM AUTHOR]

Using optical absorbers is one approach to manage and decrease the intensity of any light source. The digital light processing (DLP) additive manufacturing system created and implemented by the authors of this article was utilized in this study to examine the impact of ultraviolet light absorber on the quality of manufacturing 3D items. The article's major objectives are to enhance part appearance quality, maximize printing control, and reduce excess light, but in order to do so, it is crucial to measure the height of separation, the degree of part damage and the Separation Force. Undoubtedly, one of the factors having the most impact on the aforementioned scenarios will be the optical absorber. Therefore, in this system, acrylic sheets are coated with polyester films that have an absorption percentage of 45% at specific distances from the light source. Then, using the DLP method, three-dimensional models were created and assessed by measuring the intensity of the transmitted light. According to the study's findings, using absorbers decreased the time it took to separate each layer by 3.5 times, cut the time it took to print a part by 43%, and increased the success of printing, while also increasing the product's aesthetic quality. [ABSTRACT FROM AUTHOR]

The control pests and diseases is considered one of the most important operations of Citrus in the protection stage. Today, a lot of research has been done in various fields of agriculture, including the diagnosis of plant pests and diseases by using machine vision methods. One of the problems that reduce the accuracy of the machine for detecting pests in farm conditions is the presence of adverse factors such as shade and changes in light intensity at different times of the day. In this study, in order to find the appropriate light intensity at different times of the day and increase the brightness of the shady parts of the trees, lighting by a lamp at the imaging site has been used. For detect pest-infected trees (in this snail study) has been used to Deep learning method which has been studied and evaluated by various optimization algorithms such as RMSProp, Adam and SGDm. To evaluate and test the algorithm used, 8000 images were examined in 9 farm conditions and one laboratory state In farm conditions, the lowest detection accuracy of algorithms with 64.32% related to imaging in cloudy days with light intensity of 350 to 700 lux was obtained using RMSProp algorithm, which Detection accuracy was improved up to 95.25% using SGDm algorithm by creating a light intensity controlled by a lamp (approximately 9000 lux). In laboratory conditions where the images were prepared in a controlled environment with constant light intensity, the detection accuracy was Obtained 98.73% with SGDm algorithm. [ABSTRACT FROM AUTHOR]

Objective: Light-cured composites and restorative materials are widely used in dentistry. The success of restoration largely depends on the effectiveness of the curing light, including the duration of irradiation and wavelength. This study was conducted to evaluate the effectiveness of curing light devices routinely used in dental offices of Karaj in 2016. Methods: In this descriptive-analytical study, 120 QTH and LED curing light devices used in Karaj dental offices were randomly evaluated. A standard questionnaire was used to collect the variables of the device type, age, and brand, number of repairs, reasons for repair, time of last repair, number of bulb replacements, time of last bulb replacement, device being fitted with a measure severity, duration of irradiation for each composite layer, frequency of using the equipment in a day, sterilization method, light intensity, and number of office days in a week. Data were analyzed with SPSS using Spearman correlation coefficient, independent t test, and chi-square at a level of 0.05%. Results: The results showed that the light intensity of all devices was above 200 mw/cm2. The light intensity of 11.1% of QTH devices was unfavorable while the light intensity of all LED devices was favorable. The results showed a significant correlation between brand and light intensity, between the number of bulb replacement and device type, between the number of bulb replacements and light intensity, between the number of bulb replacements and clinical age of the device, and between the number of repairs and the device type (P≤0.05). There was no significant relationship between the device type and repair reason. The results also showed an indirect relationship between the clinical age of the device and light intensity. A significant difference was found in light intensity between QTH and LED devices. Conclusion: The light intensity of 11.1% of QTH devices was unfavorable, and the main reason for repair was tip breakage. Light intensity decreased with an increase in the clinical age of the device; therefore, regular quality control and timely bulb replacement are of great importance.

Introduction: Among the photosynthetic microorganisms, cyanobacteria belonging to the genus Fischerella appear particularly promising for new polysaccharides producing strains. Extracellular polysaccharides (EPS) serve as a boundary to the immediate environment and play a protective role against antimicrobial agents. That iswhy cyanobacteria are so popular in the industry today as thickeners or floating agents, heavy metal absorbers, or in the case of sulfate polysaccharides as bioactive substances. This is an advantage over other polysaccharides extracted from plants or other macroalgae. There are many factors affecting cell growth and metabolite accumulation in cell cultures. However, there is insufficient knowledge about the factors affecting maximal EPS biosynthesis and antibacterial activity. In this regard, in this paper, the effect of some physical, environmental, and nutritional factors on the simultaneous production of exopolysaccharide by Fischerella sp. SH.A was investigated in order to select the best cultivation conditions for the industrial application of exopolysaccharides. Materials and methods: In this study, the cyanobacterium isolated from the fresh water of Golestan province was undertaken with the aim of investigating the key factors regulating EPS biosynthesis and antibacterial activity. After the morphological and molecular identification, the possible correlations between the type of stress and the amount of polysaccharides production were also investigated. Results: The obtained results indicated that EPS production and antibacterial activity were highly dependent on the culture conditions and light intensity. Furthermore, the production of exopolysaccharides in non-diastrophic conditions was highly correlated with the concentration of nitrate up to 500 mM and the illumination of 50 or 150 microeinsteins per second per square meter. Discussion and conclusion: Since cyanobacterial extracellular polysaccharides are interesting from the biotechnological point of view, considering some other parameters are of crucial importance for the maximization of EPS production in this genus. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the image processing technique in rice blast disease detection in field and controlled conditions. Using MATLAB software, images taken from field and controlled conditions were processed in three RGB, HSI and LAB color spaces. Then it was extracted by the gray area intensity profile, color properties, and threshold value for background image removal. After removing background in RGB, HSI and LAB color spaces, disease spots on rice leaf were determined. In RGB color space, by subtracting arrays by test and error, the blast patches on the leaf were separated from the rest of the image pixels. Hue was used in the HSI color space because this component was independent of light intensity variations, so blast blot identification was performed more accurately than the S and I components. In the LAB color space, the Kmeans clustering algorithm was used to segment the images into three clusters and was displayed in an independent cluster after labeling the image of blast disease spots. Finally, in order to determine the performance of the algorithms designed in three color spaces, the sensitivity factor, specificity and total accuracy were tested on the basis of the perturbation matrix for 500 image samples. In field and controlled conditions, the highest accuracy in detecting blast blots in the LAB color space was 94% and 98%, respectively. Overall, the results showed that the image processing method can be used to detect rice blast disease. [ABSTRACT FROM AUTHOR]

In the present research, the steam generation performances of nanofluids containing titanium dioxide have experimentally been examined. For this purpose, a solar simulator with a xenon lamp as the radiation source, and a pyranometer as a light intensity measuring device are used. Then, the water based-nanofluids in five nanoparticle mass fractions of 0.001, 0.002, 0.004, 0.04, and 0.08% exposed to the light intensity of 3.5Suns (3.5 kW/m2) were investigated to compare their evaporation performances with water (H2O). Finally, the effects of the solar power intensity on the steam generation were examined. The results showed that the titanium dioxide nanostructures are more efficient to directly absorb the solar energy than the water so that the maximum total evaporation efficiency of 77.4% and 54% were obtained at 3.5 kW.m-2 for nanofluid and water, respectively. Furthermore, it was found that light absorption increases as the nanofluid mass fraction increases. Also, increasing the light intensity from 1.5 to 3.5 kW.m-2 enhances the thermal efficiency, while it reduces the evaporation efficiency. [ABSTRACT FROM AUTHOR]

This study investigated the integrated effects of two photoperiods (16:08 and 08:16 h) along with three light intensities (3000, 15000 and 50000 lux) on some reproductive parameters and broodstock survival rates of Artemia parthenogenetica in six treatments in a completely randomized factorial design in culture system until death. Two-way ANOVA analysis revealed significant differences in total offspring production, percentage of pregnant females, offspring per broodstock and encysted-embryos percentage during different weeks between treatments. In each photoperiodic levels, increasing of illumination caused a decreasing trend in weekly offspring production. The highest offspring production was obtained in the females cultured in 3000 lux (at two photoperiods) in the first seven weeks (800-1400 offspring). In both photoperiods, increasing illumination causedirregular decreasing trend in the weekly average pregnant females. The interaction effects showed significant differences in the encysted-embryos percentage until the ninth weeks of culture. = The encystment percentage was higher in short photoperiod compared to longer period. In both photoperiods, the mean survival rates of females were the highest in 3000 lux (60-80%) compared to 15000 lux (28-55%) and 50000 lux (8-20%) at the first 45 days of culture. Accordingly, the treatment of 3000 lux-16:08 h was the ideal light level in the current experiments due to the highest offspring production and females’ survival rate as well as the increasing percentage of pregnant females (until six weeks), while the illumination of 50000 lux showed the lowest reproduction characteristics.

Background and Objective: Algal wastewater treatment is a new and economic technology to remove and recycle nutrients from wastewater. In order to investigate the effect of vinasse on microalgae growth and also the effect of its growth on nitrogen and phosphate removal in a mixture of urban wastewater and vinasse, the growth of Spirulina platensis was studied. Materials and Methods: Growth ability of spirulina in the urban wastewater and the effect of vinasse on growth rate was investigated by the calculation of biomass. The effect of concentration of vinasse, intensity of light and light-dark cycle on growth rate were studied by DESIGN EXPERT and CCD method. By selecting the optimized conditions, rates of nitrogen, phosphate and COD removal was investigated at the end of the growth period. Results: The results showed that adding vinasse to wastewater increased the growth rate and the highest amount of biomass of 3.19 mg/mL was obtained in the sedimentary stream containing 0.25% vinasse. By evaluating the effect of vinasse concentration, intensity of light and light-dark cycle on growth rate, optimal conditions at vinasse concentration 0.4% (v/v), light intensity of 5000 lux and light period of 10 hours, 480 (mg/L) of biomass was obtained. The percentage of removal of nitrogen, phosphate and COD was 63%, 97% and 73% respectively. Conclusion: The results of this study indicated the capability of urban wastewater and vinasse in order to replace Zarouk’s culture medium for growth of Spirulina microalgae. These microalgae were able to remove high percentage of nutrients in the wastewater. [ABSTRACT FROM AUTHOR]

Aims: Nowadays, microalgae use to produce biologically active drugs and pharmaceuticals. The carbon source is an essential factor for Spirulina maxima growth. It is valuable to find the appropriate carbon source and its concentration to achieve high levels of biomass in the shortest cultivation period. Therefore, in the present study, the effect of different carbon sources (sodium carbonate, sodium bicarbonate, glucose, and molasses) with different concentrations (16, 24, and 32gL‐1) on growth and biomass production was evaluated. Materials & Methods: Microalgae were grown in 11 treatments with 3 replications at laboratory temperature (28±3°C) and 1350±100Lux light intensity (24‐hours exposure‐time). The maximum specific growth rate and doubling time were calculated according to nonlinear modeling by Wolfram Mathematica 11.3 software at a 99% confidence interval. Findings: The highest biomass concentration (gL‐1) at the highest carbon source concentration in the first 5 days belongs to molasses (3.083), glucose (2.094), sodium carbonate (0.869), and sodium bicarbonate (0.835). Biomass production of treatments except for glucose in medium was increased by increasing concentration from 16 to 32gL‐1. Although molasses has reached the highest biomass production during the first 5 days of cultivation, the greatest effect on increasing specific growth rate belongs to the glucose sample. Conclusion: The carbon source and its concentration had a significant effect on growth and biomass production. Glucose was selected as an effective carbon source for growth with a concentration of 24gL‐1. Moreover, the highest concentration of treatments had shown the least effect on the specific growth rate. [ABSTRACT FROM AUTHOR]

Soil organic carbon pools (SOCP) in forests play important roles in terms of biomass productivity level as well as mitigating the climate change effects. Land-use changes cause a potential loss of SOCPs in the forest. Hence, variation of SOCPs around the forest-paddy field transition zone in northern Iran was the main aim of this study. The study was conducted within the natural forest park forest of Nour in Mazandaran province, in which the weak drainage and long periods of soil waterlogging during the rainy season are considered as crucial threats. In two remnant forest fragments with similar stand type (Maple-Ironwood), extend (10 ha) and location (adjacent to the paddy fields), soil samples were collected from two depths of 0- 20 and 20-40 cm at five distances from the farm edge into the inner forest (10 m in the paddy field and 0–10, 30–40, 70–80 and 100–110 m towards the forest interior). All the samples were collected near to the dominant Acer velutinum trees, with a minimum distance of 10 m to each other. In addition, light intensity was measured based on v per m2 in the growing season by photo-light meter measuring device in constant vertical distance from the ground. The result of paired t-test showed significantly higher carbon budget in upper soil depth compared to the lower depth in both forest and paddy fields (P < 0.01). The result of one-way ANOVA indicated no significant differences among different distances to the forest stands (P>0.05). Surprisingly we observed no significant difference between the SOCPs in forest and paddy field. Besides, a significant inverse Pearson’s correlation between light intensity and SOCP was only observed for the upper soil depth in forest and paddy field (r=-0.37, P < 0.05).

Background and Objectives: Carpet weaver women due to long working in inappropriate environment are at risk for certain eye disease. The aim of this study is to determine the refractive errors among carpet weavers women in rural Sephidehkesh of Qazvin.Methods: 28 Carpet weaver women were under optometric eye examinations. Light Intensity at work stations was measured, using luxmeter and eye examinations were done by using the ophthalmoscope and retinoscop. Data were analyzed using one-side T-test.Results: The result of this study showed, general and local light intensity in 13 carpet weaving workshops, respectively 160 and 154 Lux that was much less than the minimum and maximum recommended values of 200 to 300 Lux. Only one of 28 Carpet weaver women was healthy and others were visually impaired. In addition to poor eyesight, workers complained of headache, itching and burning eyes.Conclusion: The results show, due to inappropriate working condition in carpet weaving workshops, most young workers are suffering from eye impairment and is predicted the severity of myopia to increase with working experience and age.

Background and Objectives: Carpet weaver women due to long working in inappropriate environment are at risk for certain eye disease. The aim of this study is to determine the refractive errors among carpet weavers women in rural Sephidehkesh of Qazvin. Methods: 28 Carpet weaver women were under optometric eye examinations. Light Intensity at work stations was measured, using luxmeter and eye examinations were done by using the ophthalmoscope and retinoscop. Data were analyzed using one-side T-test. Results: The result of this study showed, general and local light intensity in 13 carpet weaving workshops, respectively 160 and 154 Lux that was much less than the minimum and maximum recommended values of 200 to 300 Lux. Only one of 28 Carpet weaver women was healthy and others were visually impaired. In addition to poor eyesight, workers complained of headache, itching and burning eyes. Conclusion: The results show, due to inappropriate working condition in carpet weaving workshops, most young workers are suffering from eye impairment and is predicted the severity of myopia to increase with working experience and age.

AbstractIntroduction: Incomplete polymerization of composite resins has unfavorable effects on the clinical function and the esthetics of the restoration. The aim of this study was to determine the relationship between the light intensity of light-curing units in the Department of Operative Dentistry of Isfahan Faculty of Dentistry and the curing depth according to ISO 4049 standards and also to compare the primary and final light densities of the units.Materials and Methods: In this in vitro study, first the light intensities of 9 light-curing units of the Department of Operative Dentistry were measured by a radiometer. According to ISO 4049 if the intensity of the light-curing unit was higher than 200 mW/cm2, the unit was used to cure five samples of Z100 composite resin. A total of 7 units were used to cure 35 specimens. The exposure time of the units with 200-300 mW/cm2 light intensity was twice those of units with over 300 mW/cm2. The uncured composite resins were removed by scraping and half of the least remaining composite resin thickness was recorded as the curing depth. Finally the light intensity of each unit was measured again. Data was analyzed with SPSS using t-test and correlation coefficient (α = 0.05).Results: The light intensity of light-curing units was 40‒620 mW/cm2: four units with above 300 mW/cm2; three with 200-300 mW/cm2 and two with less than 200 mW/cm2. Only two light-curing units exhibited significant differences between primary and final light intensities (p value < 0.001). The correlation coefficient between the light intensity and curing depth was 0.58. All the curing depths were within the ranges of ISO 4049 standards regardless of duration of exposure.Conclusion: All the light-curing units with a light intensity of more than 200 mW/cm2 had achieved the necessary curing depth specified by ISO 4049 and there was a positive correlation between light intensity and curing depth. Key words: Light curing unit, Light intensity, Composite resin, Polymerization.

The effect of four light intensities (0, 100, 2000 and 5000 lux) on some reproductive charachteristicsof Artemiaurmianabroodstocks was investigated. 30 male and female individuals were reared in 3 liter containers until the death of all females over the consecutive weeks. Results showed significant differences in terms of average weekly offspring productions among the treatments. The broodstocks cultured in 5000 lux had an increasing trend in offspring production from the first to the fifth week, but a decreasing trend from the sixth to the tenth week. A relatively similar situation was observed in the 2000 lux treatment. The broodstocks cultured in 0 and 100 lux intensities had reduction fluctuations in offspring production from the first to the sixth and seventh weeks, respectively. The highest percentages of egg-sac females were observed in the early and mid-raising weeks, showing the maximum in the mid-week (until the fifth week) in all treatments. In most weeks, a considerable increase was detected in the encysted embryos production in the broodstocks reared in 0 and 100 lux intensities as compared with 2000 and 5000 lux intensities. The survival percentage of broodstocks at the end of the fifth week was 95, 86, 23 and 30 % (in order from high to low levels of light intensities).Considering the increased production of offspring and higher survival rate in the broodstocks as well as the increase in egg-sacsfemales (during the first five weeks), it is recommended that the light intensity of 5000 lux is useful for the mass culture of A. urmianain hatchery reared broodstock. [ABSTRACT FROM AUTHOR]

The present study was carried out with considering the problem of Quecus castaneifolia (C.A.Meyer) natural regeneration in Caspian forests and the key rule of light and vegetation competition (with dominant species of grass) in growth and establishment. For this target, homogenous, sound acorns were collected from a mature tree and directly sown in an open area of Caspian plain forest, Noor region (15 m a.s.l.). The experimental design was based on factorial and completely randomized blocks with cleaning treatment (weed removal, weed competition or control) and light treatment (full light and 40% shade). To make a shadow, the wooden network with 100 cm in height was applied. Results at the end of third growth season revealed that under weed competition, height growth, collar diameter and number of branches of Q. castaneifolia seedlings were significantly decreased but survival did not differ. With increasing light intensity, number of branch was significantly increased, but no significant difference obtained in survival rate, height growth and collar diameter growth. Survival did not decrease from 86.4% in competition with weed and from 90.6% in full light. It is deduced that growth and establishment of Q.castaneifolia in open areas, like in shaded places, has been successful. So, it can be suggested that direct seeding of Q. castaneifolia is a suitable method for restoration of degraded and non-regenerated areas in some lowland forests of northern Iran. In these conditions to reduce competition in early years it is better to use weeding practices around the seedling following direct seeding.