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Auswahl der wissenschaftlichen Literatur zum Thema „Length of sunlight“
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Zeitschriftenartikel zum Thema "Length of sunlight"
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Benedetti, Francesco, Cristina Colombo, Barbara Barbini, Euridice Campori und Enrico Smeraldi. „Morning sunlight reduces length of hospitalization in bipolar depression“. Journal of Affective Disorders 62, Nr. 3 (Februar 2001): 221–23. http://dx.doi.org/10.1016/s0165-0327(00)00149-x.
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Lilabati, Laishram, und U. K. Sahoo. „Germination and Growth Behaviour of Seedlings of Emblica ofƒicinalis Gaertn under Different Light and Nutrient Regimes in Field Conditions“. Science & Technology Journal 4, Nr. 2 (01.07.2016): 98–104. http://dx.doi.org/10.22232/stj.2016.04.02.03.
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Emblica officinalis Gaertn. is an important non-timber forest product plant which is known in improving livelihood of the people of north-east India. This plant is widely used in the Indian system of medicines and believed to increase the body immunity against diseases. A trial was made to assess the initial growth performance of seedlings of E. officinalis under three light regimes viz. Open-100% ambient sunlight (FAL), partial-80% ambient sunlight (PAL) and deep shade-40% ambient sunlight (DAL) and four nutrient conditions (NPK, saw dust biochar, cowdung and untreated) during a 3-months period in the Department of Forestry Mizoram University, Mizoram India. After 12 weeks of exposure to different light regimes and nutrient conditions, initial growth parameters of the seedlings like number of leaves, shoot length, root length, biomass and vigour index measured in order to understand the best growth conditions for the plant. The results reveal that seed germination and other growth parameters were significantly (P<0.05) influenced by light regimes and nutrient treatments. The seedling height, number of leaves, shoot length, root length and biomass was significantly higher under FAL. All growth parameters including seed germination were poor under DAL.
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Mo, Yan, Guangyong Li, Dan Wang, Jiandong Wang, Haidong Chai und Xiuming Zou. „Mechanism of Sunlight Damage on Drip Tape by Pendant Droplets in Mulched Drip Irrigation“. Transactions of the ASABE 61, Nr. 6 (2018): 1969–75. http://dx.doi.org/10.13031/trans.12979.
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Abstract. Drip irrigation under mulch has been applied in China for nearly 20 years, but sunlight damage from the lens effect through droplets beneath clear plastic mulch is always a problem that cannot be ignored. Droplet volume and mulch wettability affect the geometric parameters of the pendant droplets. Changes in geometric parameters were experimentally investigated by analyzing side-view images of droplets. Models were built to predict droplet focal length and light-gathering power based on the geometric parameters. A comparison between numerical and optical experimental results suggested that the focal length model was accurate and reliable. The effective incident area of the parallel light proposed in this study could also be used to represent the light-gathering power, which had a relationship with the drip tape burning rate. The increase in wettability of the clear mulch considerably increased the focal length of the pendant droplets, expanded the focal length range, enhanced the light-gathering power, and thus increased the risk of drip tape burning. In practice, pendant droplets with a wetting radius of 3 to 5 mm, with corresponding focal lengths of 5 to 12 mm, have a high probability of emergence. Therefore, the distance between the mulch and drip tape should be beyond this focal length range to reduce the risk of drip tape burning by pendant droplets. In addition, filming the mulch surface with hydrophobic materials to increase the contact angles of droplets can also protect the drip tape from sunlight damage. Keywords: Drip irrigation under mulch, Drip tape burning, Effective incident area of parallel light, Focal length, Pendant droplet.
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Senthilnathan, Anoja, D. M. S. N. Dissanayake, G. T. D. Chandrakumara, M. M. M. G. P. G. Mantilaka, R. M. G. Rajapakse, H. M. T. G. A. Pitawala und K. M. Nalin de Silva. „Akaganeite nanorices deposited muscovite mica surfaces as sunlight active green photocatalyst“. Royal Society Open Science 6, Nr. 3 (März 2019): 182212. http://dx.doi.org/10.1098/rsos.182212.
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Thin films of akaganeite [FeO(OH)] nanorices deposited muscovite mica (ANPM) surfaces are synthesized using the facile urea assisted controlled self-assembly technique. The synthesized materials are characterized using scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy, atomic force microscopy, X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and thermogravimetric analysis (TGA). The prepared nanorices on mica surfaces show average particle length and width of 200 and 50 nm, respectively. Synthesized material acts as an efficient photocatalyst under UV and sunlight conditions as demonstrated by the degradation of standard methylene blue (MB) solution. The MB degradation efficiencies of the catalyst under exposure to 180 min sunlight and UV are 89% and 87.5%, respectively, which shows that the catalyst is more highly active under sunlight than under UV light. Therefore, the synthesized material is a potential green photocatalyst in efficient treatment of industrial dye effluents under direct sunlight.
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Schluckebier, J. G., und C. A. Martin. „Effects of Above-Ground Pot-in-Pot (PIP) Placement and Humic Acid Extract on Growth of Crape Myrtle“. Journal of Environmental Horticulture 15, Nr. 1 (01.03.1997): 41–44. http://dx.doi.org/10.24266/0738-2898-15.1.41.
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Abstract Rooted cuttings of crape myrtle (Lagerstroemia indica L. × L. fauriei Koehne ‘Muskogee’) were potted into 3.8 liter (1 gal) black polyethylene containers and subjected for two months to one of three above-ground shielding treatments; containers placed pot-in-pot (PIP) for two months, containers exposed to direct sunlight for two months, or containers placed PIP for one month and then exposed to sunlight for one month (PIP/exposed). Mean daily maximum temperatures in rooting substrate of containers exposed to sunlight were as much as 16C (29F) higher than PIP containers. Plants in containers exposed to sunlight for two months had less total root and shoot length and higher concentrations of leaf nitrogen compared with the other two treatments. Plants were next transplanted into 27-liter (7-gal) polybags filled with a landscape substrate and fertigated with a humic acid extract at 0, 50, 150, or 300 μL/L for two additional months. The change in shoot and root length of plants previously placed PIP for two months responded in quadratic fashion to increased humic acid extract concentration levels; the most response occurred at about 50 μL/L while the highest concentrations inhibited post-transplant growth. Growth inhibition caused by heat stress as a result of exposure of container walls to insolation was still evident two months after transplanting.
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Hawley, A. L., und H. J. Fallowfield. „Pond walls: inclined planes to improve pathogen removal in pond systems for wastewater treatment?“ Water Science and Technology 78, Nr. 1 (14.06.2018): 31–36. http://dx.doi.org/10.2166/wst.2018.269.
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Abstract Attenuation of sunlight in wastewater treatment ponds reduces the depth of the water exposed to disinfecting irradiances. Shallow pond depth with paddlewheel rotation increases exposure of pathogens to sunlight in high rate algal ponds. Generation of thin films, using pond walls as inclined planes, may increase inactivation of pathogens by increasing sunlight exposure. The performance of a laboratory based model system incorporating an inclined plane (IP) was evaluated. F-RNA bacteriophage, in tap water or wastewater, was exposed to sunlight only on the IP with the bulk water incubated in the dark. MS2 inactivation was significantly higher when the IP was present (P < 0.05) with a 63% increase observed. Prolonged exposure increased MS2 die-off irrespective of IP presence. Versatility of the IP was also demonstrated with faster inactivation observed in both optically clear tap water and wastewaters. IPs of different surface areas produced similar inactivation rates when operated at similar hydraulic loading rates regardless of slope length.
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Marler, Thomas E., Bruce Schaffer und Jonathan H. Crane. „Developmental Light Level Affects Growth, Morphology, and Leaf Physiology of Young Carambola Trees“. Journal of the American Society for Horticultural Science 119, Nr. 4 (Juli 1994): 711–18. http://dx.doi.org/10.21273/jashs.119.4.711.
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Growth and leaf physiology responses of container-grown `Arkin' carambola (Averrhoa carambola L.) trees to long-term exposure of ≈25%, ≈50%, or 100% sunlight were studied in four experiments in Guam and Florida. Shading increased rachis length and leaflet area, and decreased leaflet thickness. Shaded trees also had a more horizontal branch orientation. Shading reduced dark respiration (Rd) and light compensation and saturation points but increased chlorophyll concentration and N-use efficiency. Light-saturated net CO2 assimilation (A) was not affected by developmental light level. Trees in full sun had smaller total leaf area, canopy diameter, and shoot: root ratio and exhibited leaflet movement to avoid direct solar radiation. Also, trees grown in 100% sunlight had a more vertical branch orientation and greater stomatal density than shaded trees. The ratio of variable to maximum fluorescence (Fv/Fm) declined during midday in 100% sunlight trees. This pattern was accompanied by a midday suppression of A in 100% sunlight-grown trees in Guam. `Arkin' carambola trees exposed to ≈25%, ≈50%, or 100% sunlight for up to 39 weeks exhibited physiological and morphological adaptations that resulted in similar growth. These results indicate that carambola efficiently adapts to different developmental light intensities.
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Mizell, R. F., D. E. Schiffhauer und J. L. Taylor. „MORTALITY OF TETRANYCHUS URTICAE KOCH (ACARI: TETRANYCHIDAE) FROM ABAMECTIN RESIDUES: EFFECTS OF HOST PLANT, LIGHT, AND SURFACTANTS“. Journal of Entomological Science 21, Nr. 4 (01.10.1986): 329–37. http://dx.doi.org/10.18474/0749-8004-21.4.329.
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Residues of abamectin (avermectin, Avid), 15 ppm; abamectin + Leaf Act 80, 15 + 25 ppm; abamectin + Sunspray oil, 15 + 25 ppm, and a water control were evaluated for length of control of twospotted spider mite, Tetranychus urticae Koch, on 3 host species: azalea, Rhododendron × ‘Red Ruffle’; lima bean, Phaseolus limensis var. limenus L. H. Bailey cv. ‘Henderson’ bush; and peach, Prunus persica L. Batsch cv. ‘Nemaguard’; and under sunlight and fluorescent light regimes. Abamectin alone or in combination with the surfactants, 21 days post treatment, resulted in 42.6 – 91.8% and 88 – 93% mite mortality under sunlight and fluorescent light, respectively. No treatments on azalea or peach under sunlight caused > 37% mortality. Treatments caused similar mite mortality 1 day posttreatment under fluorescent light, but after day 1 treatments on peach caused < 62 % mortality while treatments on azalea caused < 46% mortality. The addition of oil increased mite mortality significantly on beans under sunlight at 14 days. At 21 days both Leaf Act 80 and oil increased mite mortality on bean compared to abamectin alone.
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Hou, Lin Rui, und Chang Zhou Yuan. „Facile Fabrication of Taper-Like BiVO4 Nanorods with High Photocatalytic Property under Sunlight Irradiation“. Advanced Materials Research 96 (Januar 2010): 87–92. http://dx.doi.org/10.4028/www.scientific.net/amr.96.87.
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We report the synthesis of the taper-like BiVO4 nanorods by employing a solid-state grinding synthetic strategy. The X-ray diffraction (XRD) indicates that the as-prepared BiVO4 nanorods were crystallized in a monoclinic system. The diameter and length of taper-like nanorods are confirmed by the scanning electron microscopy (SEM) technology. The diameter and length of the taper-like nanorods are 100 nm and 1 μm, respectively. And the photocatalytic activity of the taper-like BiVO4 nanorods was evaluated by measuring the degradation of methylene blue (MB) in water under sunlight irradiation. MB was degraded nearly to nothing under sunlight irradiation for 120 min at room temperature in air. These results indicate the as-prepared product is a good sun-driven photocatalyst. In addition, the degradation mechanism of methylene blue over BiVO4 nanorods was tentatively investigated.
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Cornea-Cipcigan, Mihaiela, Doru Pamfil, Cristian Radu Sisea und Rodica Mărgăoan. „Gibberellic Acid Can Improve Seed Germination and Ornamental Quality of Selected Cyclamen Species Grown Under Short and Long Days“. Agronomy 10, Nr. 4 (03.04.2020): 516. http://dx.doi.org/10.3390/agronomy10040516.
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Cyclamen species (swinebread spp.) are perennial herbaceous plants which belong to the Primulaceae family, widely used as medicinal or ornamental plants. Currently, gibberellic acid (GA3), an environmentally friendly bioregulator is widely used to enhance the productivity and phenotypic characteristics of multiple ornamental crops. A dual experiment was conducted to evaluate the influence of gibberellic acid (50, 100 or 150 mg/L), on germination earliness of seeds, along with growth and ornamental quality of selected Cyclamen species. Additionally, a greenhouse experiment with long and short sunlight photoperiod was conducted to evaluate its importance in the development of Cyclamen plants. Our results indicated that under short sunlight exposure, seeds germinated earlier than those kept in long sunlight photoperiod. Plants treated with foliar applications of GA3 exhibited higher plant height, leaf area, number of leaves, root length and tuber development. Significant differences were found in germination percentage (GP), mean germination time (MGT) and seedling vigor index (SVI), within different GA3 supplementation and greenhouse sunlight intensity (short and long days). In conclusion, our study suggests that seedling vigor and ornamental quality can be increased by GA3 application, an economic strategy for enhancing germination and growth of selected Cyclamen species.
Dissertationen zum Thema "Length of sunlight"
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Tomanová, Helena. „Závislost hodnot UV indexu na vybraných parametrech“. Master's thesis, 2021. http://www.nusl.cz/ntk/nusl-445942.
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Relationship between the UV index and selected parameters Abstract Ultraviolet radiation (UV radiation) is a shortwave radiation with wavelengths from 100 to 400 nm. This radiation has both positive and negative effects on living organisms and human health. Therefor the so-called UV index (UVI), characterizing the biological effect of UV radiation on human health was defined in 1994. This thesis aims to evaluate the link between selected factors (total ozone column, solar elevation angel, cloudiness and altitude) and the UVI values. Observed data at four stations in Czechia (Hradec Králové, Košetice, Kuchařovice, Labská bouda) and SYNOP reports from the four nearest stations during the period 2010−2017 were used. The Sun elevation (angle of Sun ray) has the strongest effect on the UVI values. The highest UVI values are generally reached at high angels when the Sun rays go the shortest path through the atmosphere. The increase of the UVI is exponential, from an angle of 30ř the increase is approximately linear. The UVI values increase on average by 0.8 at the Hradec Králové station and by 0.9 at the Labská bouda station for angle increasing by 5ř. The effect of clouds is significant and depends on the height and the clouds amount. High level clouds reduce UVI negligible, overcast sky by only 15 %. Medium and...
Buchteile zum Thema "Length of sunlight"
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Whiteman, C. David. „Four Factors That Determine Climate“. In Mountain Meteorology. Oxford University Press, 2000. http://dx.doi.org/10.1093/oso/9780195132717.003.0007.
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Climate differs from one location to another because of differences in • latitude, the angular distance north or south from the equator • altitude, the height above sea level • continentality, the distance from the sea • exposure to regional circulations, including winds and ocean currents. The latitude of a given site determines the length of the day and the angle of incoming sunlight and therefore the amount of solar radiation received at that site. Seasonal and diurnal (day—night) variations in the amount of solar radiation received cause seasonal and diurnal variations in the weather. Near the equator, the days of the year are all about the same length, and the noon sun is nearly overhead year-round. Because day length and solar angle change little with the season, there is little seasonal variability in the weather. In the polar regions, on the other hand, the sun does not rise at all in the winter, and in the summer it never sets, although it remains low in the sky. Thus, polar weather has a high seasonal variability, but a low diurnal variability. In the midlatitudes, the climate is characterized by both seasonal and diurnal changes. Except at the equator, day length varies throughout the year. In the Northern Hemisphere, the longest day of the year is at the summer solstice (June 21), the shortest day of the year is at the winter solstice (December 21), and the day is 12 hours long on the vernal and autumnal equinoxes (March 20 and September 22). The altitude angle of the sun also varies throughout the year, with an increase of about 47° from winter to summer. The more direct summer sunlight produces more heating than the slanted rays of the winter sun. The latitude of a given site affects its climate not only because it determines the angle of solar radiation and the length of a day, but also because it determines the site’s exposure to latitudinal belts of surface high and low pressure that encircle the earth.
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Steinberg, Paul F. „A Perilous Journey“. In Who Rules the Earth? Oxford University Press, 2015. http://dx.doi.org/10.1093/oso/9780199896615.003.0009.
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For sheer splendor, few natural wonders can outperform the seasonal migration of birds across the planet. Each year about 100 billion birds traverse the globe in search of greener pastures during the winter and return to their mating grounds when temperatures warm. Record-holders like the Arctic Tern travel thousands of miles to reach their destination. But even the less athletic members of the avian family feel the urge. As winter approaches, groups of California mountain quail hobble along by foot 15 miles down to the safety of the valleys below, and make their way steadily back up the mountain slope come spring. On a planet dominated by human artifacts and controlled environments, birds remind us of the ancient things—cycles of nature stretching back well before the first humans walked the landscape. This is equally true of their morning song. If you stood at the North Pole with a microphone powerful enough to detect it, you would hear an enormous wave of music slowly circling the earth each day, as a chorus of millions of birds awaken, their song tracking the leading edge of sunlight moving westward around the earth’s perimeter. When we think of the study of the earth’s natural wonders, what comes to mind are images from the natural sciences—lab coats and test tubes, gloves and galoshes, fish nets and soil samples. And when we wish to learn more about our environment, we consult these same sources of expertise. Take birding guides, for example. If you visit the southeastern United States in the spring, you may be fortunate enough to catch a glimpse of an adorable little blue bird called the cerulean warbler, literally the “sky blue singer.” Consulting a trusted birding guide such as Peterson’s, you will learn certain things. The cerulean is 4½ inches in length. It has a thick pointed beak suited to its preferred diet of insects. It breeds in North America, where it builds cup-shaped nests high in the trees to hatch its chicks.
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Sivagami, Arasu, Michael Angelo Kandavalli und Bhaskarrao Yakkala. „Design and Evaluation of an Automated Monitoring and Control System for Greenhouse Crop Production“. In Next-Generation Greenhouses for Food Security. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.97316.
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An embedded system integrated with sensors based on nanomaterial is proposed for closely monitoring and control microclimate parameters 24 hours a day to maximise production over the whole crop growth season by introducing greenhouse for the cultivation of plants or specific plant species. The system will also eliminate errors in human intervention to optimise production of crops. This system consists of sensors and actuators, an Analogue to Digital Converter (ADC) and a Raspberry Pi. The system will determine whether a defined threshold is passed by any climate parameter and systematically changes via the controller. The current work reduces human input through automated irrigation to optimally utilize a scarce resource, namely water. Climatic parameters for plant growth such as, moisture, humidity, temperature, water pressure in drip pipe, soil salinity etc. are monitored and optimized. Furthermore, work was extended to include GSM to control the entire farm remotely. For its success, it is very important to choose a greenhouse location. For instance, the problems are quite different when choosing an adjoining greenhouse, for instance a sunroom or greenhouse. The greenhouse location should be chosen for sunlight, proximity to power and water sources, wind, drain and freeze pockets, and the proximity of the garden and house. The intention behind accomplishment and devise of GSM based Fertigation System is to construct and evaluate the requirement of water in the yield as farming is the major resource of production which habitually depends on the water accessibility. Irrigation of water is usually done by manual method. To ease the work of the farmer GSM based automatic Fertigation (includes chemigation too) system can be implemented so that water wastage can be reduced and also the fertilizer can be added accordingly. Also the Soil Salinity can be checked and reduced if exceeds certain limit. By using GSM, only GSM command via GSM mobile can control the start and stop action of a motor that feeds the field with the water. GSM is used for controlling the entire process and the entire system backbone. It can be used from any distance to control irrigation. The results are assessed by electronic simulator PROTEUS using the desired optimised parameters, the design of this automated greenhouse system with PIC controller. As the inputs to the microcontroller and as an LCD screen record the respective outputs, the model produces a soil moisture sensor, light sensor and temperature sensor. The system performance is accurate and repeatable for measuring and controlling the four parameters that are crucial for plant growth - temperature, humidity, soil moisture and light intensity. With the reduction in electricity consumption, maintenance and complexity, and a flexible and precise environment control form for agriculture, the new system successfully cured quite a couple of defects in existing systems. Nano composite film sensors (Graphene and Graphene mixed in order to optimise the input of fertilisers for chemical composition determination. Using nano technology in agriculture enforces the firm bond between the engineer and farmer. Nano material film-based gas sensors were used to measure the presence of oxygen and CO2.using graphene nano composite sensors integrated into an embedded system, to detect the presence and levels of gases. Improve crop growth with combined red and blue light for lighting under the leavened and solar-powered LED lighting modules. This was achieved by graph/solar cells. The light was measured at the photosynthesis flux (PPFD) of 165 μmol m-2 s-1 by 10 cm of its LED module. LED lights were provided between 4:00 a.m. and 4:00 p.m. in the daytime treatments and night treatments from 10 to 10 hours. The use of the nighttime interlumination of LEDs was also economical than the interlumination of charts. Thus, nightlighting LEDs can effectively improve plant growth and output with less energy than the summer and winter times. Solar panels are best functioning during times of strong sunlight today, but begin to wan when they become too hot and cloudy. By allowing Solar Panels to produce electricity during harsh weather conditions and increase efficiency, a breakthrough in graphene-based solar panels can change everything. Ultimately with a fully autonomous system, agricultural productivity and efficiency, the length of the growing season, energy consumption and water consumption were recorded and monitored by exporting the data over GSM environment. With the steady decrease in the cost of high-performing hardware and software, the increased acceptance of self-employed farming systems, and the emerging agricultural system industry, the results will be reliable control systems covering various aspects of quality and production quantity.
Konferenzberichte zum Thema "Length of sunlight"
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Kang, Kyungnam, Changjoo Lee, Sungchul Kim und Jungho Kim. „Effect of the coherence length of sunlight on the absorption of V-shaped organic solar cells“. In 2015 11th Conference on Lasers and Electro-Optics Pacific Rim (CLEO-PR). IEEE, 2015. http://dx.doi.org/10.1109/cleopr.2015.7376569.
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Sadasivuni, Cherishma, Dan Dye und Byard Wood. „Ray Trace Analysis for Concentrating Sunlight Onto an Optical Fiber Bundle“. In ASME 2006 International Solar Energy Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/isec2006-99077.
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A two-axis concentrating solar collector/receiver is being designed to concentrate visible solar irradiance and distribute it inside a building for daylighting via a bundle of polymer optical fibers. This paper is concerned with the optics that will provide uniform illuminance of the visible spectrum on the entrance of the fiber optic bundle. A fiber optic bundle made of 3mm diameter fibers and a non-imaging device along with the solar collector’s primary and secondary mirrors has been modeled in a ray-tracing software package, TracePro 3.3. Fiber optic bundles of two different geometries were considered, viz. a square bundle with 225 fibers and a round bundle consisting of 126 fibers. The purpose of this research is to determine the optimum length of the non-imaging device that could provide uniform illuminance on the entrance area of the fiber optic bundles. Sensitivity analyses are conducted to see the variations in the output due to different possible off-set conditions, such as distance between the primary and the secondary mirror, the secondary mirror off-set from the primary mirror optical axis, and misalignment due to tracking error. The results of the sensitivity analyses are presented, and recommendations are made for the design of the non-imaging device. It is shown that the square non-imaging device and fiber bundle is superior to the round non-imaging device and fiber bundle.
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Angel, Roger, und Justin Hyatt. „Track and Tilt Collection for Central Receiver CSP“. In ASME 2016 10th International Conference on Energy Sustainability collocated with the ASME 2016 Power Conference and the ASME 2016 14th International Conference on Fuel Cell Science, Engineering and Technology. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/es2016-59618.
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Here we describe a new type of point-focus solar collector for CSP called “track and tilt”. It bridges the gap between dish and heliostat arrays collectors, having the high optical efficiency of a dish but with larger aperture (> 1000 m2) focused to a tower mounted receiver in fixed gravity orientation. It is well matched to the next generation of high efficiency cavity receivers transferring heat to a storage medium at temperatures exceeding 700C. The collector uses silvered glass reflectors mounted on a rotating, rigid structure in the form of a 120 degree conical arc. In operation, this large structure rotates in azimuth on a track around the central receiver tower, keeping the gravity load on the structure constant. The central receiver is rotated about a vertical axis so as to face the reflector arc. The reflectors are concave, all with the same focal length, and are individually tilted to follow solar elevation to focus sunlight onto the tower-mounted receiver. A detailed optical model made of a collector with 40 m focal length has 1,450 m2 total reflector area, and delivers on average 1.2MW of sunlight to the receiver, (under 1000 W/m2 DNI and allowing for reflector and small geometric losses). The collector forms an only slightly aberrated image of the sun at the receiver, showing a concentration of 2000x averaged over the receiver entrance with spillage < 2%. The overall annual averaged efficiency, defined as (total sunlight energy delivered to the receiver entrance)/(direct normal irradiance × total reflector area) is >80%. This calculation includes 90% reflectivity of the mirrors. To avoid the high mass and cost of a structure which must withstand 85 mph winds, our unique arc support structure takes the form of four lightly built panels which are lowered to the ground in high wind and for maintenance. Cables from the central tower are used to lower and raise the panels into operating position where they are locked together. The top section of the tower carrying the cable mechanism and the receiver rotate on a bearing in synchronization with the track mounted reflector assembly. The small scale of the collector unit means that a first prototype of the radical new architecture can be built and tested at relatively modest cost. Higher power systems with multiple collectors and receivers might be built either with individual storage and turbines, such as sCO2, or with heat transfer to a common storage and power generation facility (as in trough systems). Continual improvements of the collector should be affordable, as system iteration costs are low.
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Sundborg, Bengt. „Making the Most of Daylight in Town Planning“. In 24th ISUF 2017 - City and Territory in the Globalization Age. Valencia: Universitat Politècnica València, 2017. http://dx.doi.org/10.4995/isuf2017.2017.6687.
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Making the most of daylight in town planning is one of the important ingredients in the attempts for the sustainable city. Exactly 150 years ago Ildefons Cerdà presented his great work “Teoría General de la Urbanización” including methods for taking care of sunlight. However, with modern software, the possibilities to do comprehensive preparations are much better. This paper presents an urban typology considering daylight with basic geometric forms, shapes and patterns. Later this will be elaborated more in detail. The research includes three steps; choosing typical alternatives for settlements and designing some new principle urban solutions, calculations and evaluations of the alternatives considering especially energy saving. The quality and the quantity of daylight are dependent of the geometry of the urban spaces. That means the volumes for the buildings as well as the empty spaces in between. The accessibility for diffuse daylight from the sky and for direct rays from the sun is measurable by computer calculations where the sun angles and the skylight from the hemisphere are simulated. Relevant parameters are height, width and length. In a settlement with a high urban density it is more difficult to distribute daylight than in a settlement with low density. However the economy for exploitations is also worse with lower density. Therefore the comparisons between different settlements are with the same density. The orientation of the settlements according to the compass is of crucial importance looking to the direct sunlight and the shadows. How the local environment with parks, water, mountains and specific landmarks in the surroundings also affects the daylight distribution is included.References (100 words) Dubois, M.-C., Gentile, N., Amorim, C., Osterhaus, W., Stoffer, S.,Jakobiak, R., Geisler-Moroder, D., Matusiak, B., Onarheim, F. M., Tetri, E. (2016) Performance Evaluation of Lighting and Daylighting Retrofits: Results from IEA SHC Task 50. (Energy Procedia. vol. 91). Littefair, P. J. (2011) Site layout planning for daylight and sunlight: a guide to good practice (BRE, Building Research Establishment, IHS BRE Press, Watford). Rode, P., Keim, C., Robazza, G., Viejo, P. and Schofield, J. (2014) Cities and energy: urban morphology and heat energy demand (LSE, London School of Economics, Cities and EIFER, European Institute for Energy Research, Karlsruhe Institute of Technology, London).
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Cates, M. R., S. L. Jaiswal, L. C. Maxey und D. D. Earl. „Characterization of Transmission Properties of 3M LF120C Plastic Optical Light Guide“. In ASME 2003 International Solar Energy Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/isec2003-44016.
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Transmission studies of 3M optical light guide, type LF120C with nominal 12.6 mm core diameter, were performed to characterize the material for use in hybrid solar lighting applications, in particular for the transport of sunlight from a collector to discrete lighting fixtures (luminaires). The light guide properties studied included: total transmission (in lumens) per unit length, transmission as a function of input angle and wavelength, transmission as a function of bend radius, and transmission through two bends. The preliminary value for total transmission is 96.6% per meter. Angular input begins to drop significantly at angles greater than 25 degrees. Wavelength transmission has significant minima at about 643 and 750 mm. Losses through bends are much greater for light input at large angles. In addition to the data compilations and detailed summaries of measurement findings, the measurement system and error sources are described.
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Muhs, Jeff, Duncan Earl, Dave Beshears und Curt Maxey. „Initial Results From an Experimental Hybrid Solar Lighting System in a Commercial Building and Overview of Related Value Propositions“. In ASME 2003 International Solar Energy Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/isec2003-44015.
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This paper describes preliminary results from research on a new hybrid solar lighting (HSL) system being developed to reduce electric lighting in commercial office buildings. A physical description of HSL system components along with preliminary results from an experimental system deployed in a commercial building in Knoxville, TN are provided. Results from a systems-level, chromaticity model are compared with experimental data. A total lumen distribution efficiency of over 50% was recorded for the initial prototype having optical fibers an average of 6 m (19.5 ft) in length. The total electrical power displacement of the 1 m2 HSL proof-of-concept prototype is estimated to be between 522–2350 watts per 1000 W/m2 of incident solar radiation on the collector depending on the type of electric lights being used in conjunction with the solar lighting system. By adding the reductions in heat gain associated with reduced electric lamp use and predicted performance improvements achieved by a system redesign, the electrical power displaced in a commercial prototype could rise to between 702–3160 W (peak)/m2 of collected sunlight not including any additional electrical power that can be generated using the otherwise wasted IR energy. The color temperature of the distributed sunlight emerging from the optical fibers is approximately 5100°K and the chromaticity values in uniform color space (u′v′) are approximately (.2010, .4977). These values match well with modeled results and will vary slightly depending on the day, time, atmospheric conditions, and system configuration. The paper concludes with a discussion of new value propositions that HSL provides architects, energy providers, building owners, and occupants and briefly outlines anticipated disadvantages.
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Wullenkord, Michael, Christian Jung und Christian Sattler. „Design of a Concentrator With a Rectangular Flat Focus and Operation With a Suspension Reactor for Experiments in the Field of Photocatalytic Water Splitting“. In ASME 2014 8th International Conference on Energy Sustainability collocated with the ASME 2014 12th International Conference on Fuel Cell Science, Engineering and Technology. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/es2014-6546.
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Photocatalytic water splitting is a potential route for future carbon-free production of hydrogen. However catalysts still need to be enhanced in order to reach acceptable solar-to-fuel efficiency. In the context of the project HyCats funded by the Federal Ministry of Education and Research of Germany a high performance test facility for the evaluation of the activity of photocatalysts under practical conditions was established. It mainly consists of a solar concentrator and a planar receiver reactor. A modified linear Fresnel concentrator configuration was chosen based on ray tracing simulation results and improved concerning the number of different facets and the tolerance of tracking errors. It meets the major demand of a homogeneous irradiance distribution on the surface of the reactor. The SoCRatus (Solar Concentrator with a Rectangular Flat Focus) is a 2-axis solar concentrator with a geometrical concentration ratio of 20.2 and an aperture area of 8.8 m2. The tracking accuracy is better than 0.1° respecting both the solar azimuth and altitude angle. Its 22 highly UV/Vis-reflective flat aluminum mirror facets reflect the sunlight resulting in a rectangular focus with a nominal width of 100 mm and a nominal length of 2500 mm. The reactor is placed in the focal plane at a distance of 2500 mm from the mounting plane of the facets and allows concentrated solar radiation to penetrate suspensions of water, electrolytes and photocatalyst particles flowing through it. Corresponding to a maximum angle of incidence of 36.6° the Quartz window reflects not more than 5% of the incoming radiation and assures only marginal absorption, particularly in the UV-part of the sun’s spectrum. The material of the receiver body is PTFE (polytetrafluoroethylene) providing reflection coefficients above 90% concerning wavelengths of UV-A and UV-B. The design of the reactor features two parallel reaction chambers, offering the possibility to test two separate suspensions at the same irradiation conditions. A pump transports the tempered suspension to the reactor. The geometry of the reactor inlet and outlet minimizes critical regions with inadequate flow caused by vortices. Any evolved gases are separated from the suspension in a tank together with nitrogen introduced in the piping upstream and are analyzed by micro chromatographs. Numerous devices are installed in order to control and monitor the reaction conditions. First experiments have been carried out using methanol as a sacrificial reagent.
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Lawless, Sean, und Ravi Gorthala. „Development of a Fiber-Optic Hybrid Day-Lighting System for Mobile Shelter Applications“. In ASME 2017 11th International Conference on Energy Sustainability collocated with the ASME 2017 Power Conference Joint With ICOPE-17, the ASME 2017 15th International Conference on Fuel Cell Science, Engineering and Technology, and the ASME 2017 Nuclear Forum. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/es2017-3563.
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This paper discusses a Fiber-Optic Hybrid Day-Lighting system that can cut energy consumed by buildings for lighting significantly. This system is designed for mobile applications such as military shelters. The system is comprised of two primary components: the solar collector and the Solar Hybrid Lighting Fixture. The first component, the solar collector, consists of a housing, structural stand, a dual axis tracking system, Fresnel Lenses, secondary optics, and fiber-optic cables. The collector is integrated into a dual-axis tracker, which is then mounted on a tripod. The tripod can be staked into the ground and weighed down to protect the system from any wind loading and the collector height can be adjusted so that there is no shading of the collector by nearby structures. The collector with an aluminum housing holds eight 10-inch diameter Fresnel Lenses that focus sunlight onto eight secondary optics based on TIR (total internal reflection) which filter UV/IR and deliver uniform light to the fiber-optic cables. The secondary optic is coupled to the fiber-optic cable with index matching gel so that Fresnel reflection losses are minimized. The solar collector tracks the sun’s movement through the day with a dual-axis tracker (azimuth/tilt), ensuring the light is concentrated into the fiber-optic cables. The optics has been designed to have a high half-acceptance of 1.75° and can accommodate a tracking accuracy of 1.50° or better. The opposite end of the fiber-optic cable attaches to the second part of the Day-Lighting system, the Solar Hybrid Light Fixture (SHLF). The SHLF comprises of two lighting systems: 1) a solar fiber-optic system and 2) an LED system. The fiber-optic cable is coupled to an acrylic light diffusing rod that evenly delivers the light into the room. During sunny periods, depending on the length of the cable, solar fiber-optic lighting could provide full illumination of the space. In order to keep lighting uniform even during fluctuations of the light output from the sun during cloudy periods, the LED portion of the light will allow for constant lighting at a lower power consumption. The LED lighting has dimming capabilities due to a photosensor that regulates the light output of the LEDs based on how much solar light is delivered by the fiber-optic cables. On a typical sunny day with an overall concentration factor of ∼400 from the Fresnel Lens system to the optical fiber, it is possible to generate an output of 2,000 lumens with a 20-foot cable, with each fiber-optic cable experiencing a 1% loss of light per foot of cable. The LED portion of the hybrid light fixture produces about 1,800 lumens as well.
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Wang, Ya, und Daniel J. Inman. „Simultaneous Energy Harvesting and Gust Alleviation for a Multifunctional Wing Spar Using Reduced Energy Control Laws via Piezoceramics“. In ASME 2011 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. ASMEDC, 2011. http://dx.doi.org/10.1115/smasis2011-5224.
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The increasing need for lightweight structures in Unmanned Aerial Vehicle (UAV) applications raise issues involving gust alleviation. Here we examine the gust alleviation problem using a self-sensing, self-charging, and self-actuating structure. The basic idea is that the wing itself is able to harvest and store energy from the normal vibrations during flight along with any available sunlight. If the wing experiences any strong, unexpected wind gust, it will sense the increased vibration levels and provide vibration control to maintain its stability. In this paper, a multifunctional wing spar is designed, which integrates a flexible solar cell array, piezoceramic wafers, a thin film battery and an electronics module into a composite structure. This multifunctional wing spar therefore carries on the functions of energy harvesting and storage, as well as the functions of gust alleviation via piezoelectric materials. The piezoceramic wafers act as sensors, actuators, and harvesters. The global modulus and stiffness of this multifunctional wing spar are estimated using both the rule of mixtures and the cross section transformation method. These values are then used in an Euler-Bernoulli cantilever beam model of the multifunctional spar. The first two dominant modes are predicted analytically for the distributed parameter model. The finite element method is employed to confirm the analytical eigenvalues estimation. Special attention is given to the self-contained gust alleviation with the goal of using harvested energy. The gust signals are generated using a Gaussian white noise source n (t) ∼ N (0,1) fed into a linear filter, with the required intensity, scale lengths, and power spectral density (PSD) function for the given flight velocity and height. The Dryden PSD function is implemented for atmospheric turbulence modeling. The recently developed reduced energy control law is combined with a positive strain feedback controller to minimize the actuation energy and the dissipated heat energy. Positive feedback operation amplifiers (op-amps) and voltage buffer op-amps are implemented for two dominant mode gust disturbance controls. This work builds off of our previous research in self-charging structures and holds promise for improving UAV performance in wind gust alleviation.