Solar drying of whole mint plant under natural and forced convection

PubMed Central

Sallam, Y.I.; Aly, M.H.; Nassar, A.F.; Mohamed, E.A.

2013-01-01

Two identical prototype solar dryers (direct and indirect) having the same dimensions were used to dry whole mint. Both prototypes were operated under natural and forced convection modes. In the case of the later one the ambient air was entered the dryer with the velocity of 4.2 m s−1. The effect of flow mode and the type of solar dryers on the drying kinetics of whole mint were investigated. Ten empirical models were used to fit the drying curves; nine of them represented well the solar drying behavior of mint. The results indicated that drying of mint under different operating conditions occurred in the falling rate period, where no constant rate period of drying was observed. Also, the obtained data revealed that the drying rate of mint under forced convection was higher than that of mint under natural convection, especially during first hours of drying (first day). The values of the effective diffusivity coefficient for the mint drying ranged between 1.2 × 10−11 and 1.33 × 10−11 m2 s−1. PMID:25750751

Solar drying of crops and food. (Latest citations from Food Science Technology Abstracts (FSTA)). Published Search

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1994-02-01

The bibliography contains citations concerning the design and utilization of solar food driers. Solar collectors used are described in depth. Drying of fish, peanuts, fruits, potatoes, onions, garlic, ginseng, grains, coffee, and tobacco using this method is discussed. The use of focused solar energy and the addition of silica gel to drying foods are evaluated. Use of solar driers in the field, as a home preservation method, in underdeveloped countries, and as part of industrial food processing is considered. (Contains a minimum of 214 citations and includes a subject term index and title list.)

Solar drying of crops and food. (Latest citations from Food Science & Technology Abstracts (FSTA)). Published Search

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1995-02-01

The bibliography contains citations concerning the design and utilization of solar food driers. Solar collectors used are described in depth. Drying of fish, peanuts, fruits, potatoes, onions, garlic, ginseng, grains, coffee, and tobacco using this method is discussed. The use of focused solar energy and the addition of silica gel to drying foods are evaluated. Use of solar driers in the field, as a home preservation method, in underdeveloped countries, and as part of industrial food processing is considered. (Contains a minimum of 217 citations and includes a subject term index and title list.)

FPL design for lumber dry kiln using solar/wood energy in tropical latitudes

Treesearch

J. L. Tschernitz; W. T. Simpson

1985-01-01

Developing countries with a timber resource that can be manufactured into finished products either for local use or export often lack the capital to build high-cost dry kilns. Many of these countries are in the tropics where solar radiation and ambient temperatures are high. The low-cost solar/wood energy lumber dry kiln described in this report was designed and tested...

Investment opportunity : the FPL low-cost solar dry kiln

Treesearch

George B. Harpole

1988-01-01

Two equations are presented that may be used to estimate a maximum investment limit and working capital requirements for the FPL low-cost solar dry kiln systems. The equations require data for drying cycle time, green lumber cost, and kiln-dried lumber costs. Results are intended to provide a preliminary estimate.

Solar drying of crops and food. (Latest citations from Food Science & Technology Abstracts (FSTA)). Published Search

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1996-04-01

The bibliography contains citations concerning the design and utilization of solar food driers. Solar collectors used are described in depth. Drying of fish, peanuts, fruits, potatoes, onions, garlic, ginseng, grains, coffee, and tobacco using this method is discussed. The use of focused solar energy and the addition of silica gel to drying foods are evaluated. Use of solar driers in the field, as a home preservation method, in underdeveloped countries, and as part of industrial food processing is considered. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

Solar Kilns: Feasibility of Utilizing Solar Energy for Drying Lumber in Developing Countries,

DTIC Science & Technology

1977-01-01

Design. .. ............. ... 52 Direct ( Greenhouse ) Design .. .. ............ ... 57 Literature Cited and Partial Bibliography of Solar Lumber Drying...experimental performance of a greenhouse -type solar kiln in Puerto Rico. (Chudnoff et al., 1966). 36"J. Table 9.--Comparison of experimental and calculated...at one dryer orientation (long axis north-south) from 30 percent to 10 percent moisture content. 49 Table 15.-- Greenhouse -type solar kiln capacity

Consumer knowledge, preference, and perceived quality of dried tomato products in Ghana.

PubMed

Owureku-Asare, Mavis; Ambrose, R P Kingsly; Oduro, Ibok; Tortoe, Charles; Saalia, Firibu K

2017-05-01

Postharvest losses (PHL) are incurred in the tomato value chain in Ghana and solar drying of tomato is a promising technology for reducing the loss. However, there are concerns on the usage, functionality and sensory appeal of the dried products to consumers, compounded with the lack of information and research on dried tomato processing in Ghana. A survey was carried out by administering semistructured questionnaires to 395 randomly selected and willing respondents in the Accra Metropolis. Information was obtained on the socioeconomic profile, consumption pattern, knowledge, and acceptance of tomato processing technologies and assessment of quality attributes important to consumers. Most consumers (74%) preferred tomato powder that is conveniently packaged to retain the characteristic intense taste and the flavor using Friedman's rank mean procedure. The study indicated that consumers were more concerned about good manufacturing practices during the production of solar-dried tomato (48.8%) rather than the quality attributes (8.6%). These findings indicate the need for safe solar drying procedures in order to increase consumer acceptability of solar-dried tomato products in Ghana.

Mathematical modelling for the drying method and smoothing drying rate using cubic spline for seaweed Kappaphycus Striatum variety Durian in a solar dryer

NASA Astrophysics Data System (ADS)

M Ali, M. K.; Ruslan, M. H.; Muthuvalu, M. S.; Wong, J.; Sulaiman, J.; Yasir, S. Md.

2014-06-01

The solar drying experiment of seaweed using Green V-Roof Hybrid Solar Drier (GVRHSD) was conducted in Semporna, Sabah under the metrological condition in Malaysia. Drying of sample seaweed in GVRHSD reduced the moisture content from about 93.4% to 8.2% in 4 days at average solar radiation of about 600W/m2 and mass flow rate about 0.5 kg/s. Generally the plots of drying rate need more smoothing compared moisture content data. Special cares is needed at low drying rates and moisture contents. It is shown the cubic spline (CS) have been found to be effective for moisture-time curves. The idea of this method consists of an approximation of data by a CS regression having first and second derivatives. The analytical differentiation of the spline regression permits the determination of instantaneous rate. The method of minimization of the functional of average risk was used successfully to solve the problem. This method permits to obtain the instantaneous rate to be obtained directly from the experimental data. The drying kinetics was fitted with six published exponential thin layer drying models. The models were fitted using the coefficient of determination (R2), and root mean square error (RMSE). The modeling of models using raw data tested with the possible of exponential drying method. The result showed that the model from Two Term was found to be the best models describe the drying behavior. Besides that, the drying rate smoothed using CS shows to be effective method for moisture-time curves good estimators as well as for the missing moisture content data of seaweed Kappaphycus Striatum Variety Durian in Solar Dryer under the condition tested.

Mathematical modelling for the drying method and smoothing drying rate using cubic spline for seaweed Kappaphycus Striatum variety Durian in a solar dryer

DOE Office of Scientific and Technical Information (OSTI.GOV)

M Ali, M. K., E-mail: majidkhankhan@ymail.com, E-mail: eutoco@gmail.com; Ruslan, M. H., E-mail: majidkhankhan@ymail.com, E-mail: eutoco@gmail.com; Muthuvalu, M. S., E-mail: sudaram-@yahoo.com, E-mail: jumat@ums.edu.my

2014-06-19

The solar drying experiment of seaweed using Green V-Roof Hybrid Solar Drier (GVRHSD) was conducted in Semporna, Sabah under the metrological condition in Malaysia. Drying of sample seaweed in GVRHSD reduced the moisture content from about 93.4% to 8.2% in 4 days at average solar radiation of about 600W/m{sup 2} and mass flow rate about 0.5 kg/s. Generally the plots of drying rate need more smoothing compared moisture content data. Special cares is needed at low drying rates and moisture contents. It is shown the cubic spline (CS) have been found to be effective for moisture-time curves. The idea ofmore » this method consists of an approximation of data by a CS regression having first and second derivatives. The analytical differentiation of the spline regression permits the determination of instantaneous rate. The method of minimization of the functional of average risk was used successfully to solve the problem. This method permits to obtain the instantaneous rate to be obtained directly from the experimental data. The drying kinetics was fitted with six published exponential thin layer drying models. The models were fitted using the coefficient of determination (R{sup 2}), and root mean square error (RMSE). The modeling of models using raw data tested with the possible of exponential drying method. The result showed that the model from Two Term was found to be the best models describe the drying behavior. Besides that, the drying rate smoothed using CS shows to be effective method for moisture-time curves good estimators as well as for the missing moisture content data of seaweed Kappaphycus Striatum Variety Durian in Solar Dryer under the condition tested.« less

Evaluation of sectrally-selective materials for multi-layer solar thermal crop drying (abstract)

USDA-ARS?s Scientific Manuscript database

Solar thermal (ST) drying is a ubiquitous method in widespread use for fruit and vegetable crop preservation in developing countries; however, it has had limited commercialization in the United States due to concerns about slow drying rates, poor product quality, and predicted low return-on-investme...

Investigation into solar drying of potato: effect of sample geometry on drying kinetics and CO2 emissions mitigation.

PubMed

Tripathy, P P

2015-03-01

Drying experiments have been performed with potato cylinders and slices using a laboratory scale designed natural convection mixed-mode solar dryer. The drying data were fitted to eight different mathematical models to predict the drying kinetics, and the validity of these models were evaluated statistically through coefficient of determination (R(2)), root mean square error (RMSE) and reduced chi-square (χ (2)). The present investigation showed that amongst all the mathematical models studied, the Modified Page model was in good agreement with the experimental drying data for both potato cylinders and slices. A mathematical framework has been proposed to estimate the performance of the food dryer in terms of net CO2 emissions mitigation potential along with unit cost of CO2 mitigation arising because of replacement of different fossil fuels by renewable solar energy. For each fossil fuel replaced, the gross annual amount of CO2 as well as net amount of annual CO2 emissions mitigation potential considering CO2 emissions embodied in the manufacture of mixed-mode solar dryer has been estimated. The CO2 mitigation potential and amount of fossil fuels saved while drying potato samples were found to be the maximum for coal followed by light diesel oil and natural gas. It was inferred from the present study that by the year 2020, 23 % of CO2 emissions can be mitigated by the use of mixed-mode solar dryer for drying of agricultural products.

Nutritional significance and acceptance of solar-dried foods of rural Leyte Philippines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Swanson, M.A.

1987-01-01

Training in solar dryer construction and food preservation was provided to villagers in three barangays in rural Leyte, Philippines. A 24 hour dietary recall assessed dietary status of the women prior to the solar dried food intervention. Nutrients of greatest dietary concern were thiamine, vitamin A, riboflavin, iron and energy.

Design of solar thermal dryers for 24-hour food drying processes (abstract)

USDA-ARS?s Scientific Manuscript database

Solar drying is a ubiquitous method that has been adopted for many years as a food preservation method. Most of the published articles in the literature provide insight on the performance of solar dryers in service but little information on the dryer construction material selection process or mater...

Comparison of three different wastewater sludge and their respective drying processes: Solar, thermal and reed beds - Impact on organic matter characteristics.

PubMed

Collard, Marie; Teychené, Benoit; Lemée, Laurent

2017-12-01

Drying process aims at minimising the volume of wastewater sludge (WWS) before disposal, however it can impact sludge characteristics. Due to its high content in organic matter (OM) and lipids, sludge are mainly valorised by land farming but can also be considered as a feedstock for biodiesel production. As sludge composition is a major parameter for the choice of disposal techniques, the objective of this study was to determine the influence of the drying process. To reach this goal, three sludges obtained from solar, reed beds and thermal drying processes were investigated at the global and molecular scales. Before the drying step the sludges presented similar physico-chemical (OM content, elemental analysis, pH, infrared spectra) characteristics and lipid contents. A strong influence of the drying process on lipids and humic-like substances contents was observed through OM fractionation. Thermochemolysis-GCMS of raw sludge and lipids revealed similar molecular content mainly constituted with steroids and fatty acids. Molecular changes were noticeable for thermal drying through differences in branched to linear fatty acids ratio. Finally the thermal drying induced a weakening of OM whereas the solar drying led to a complexification. These findings show that smooth drying processes such as solar or reed-beds are preferable for amendment production whereas thermal process leads to pellets with a high lipid content which could be considered for fuel production. Copyright © 2016 Elsevier Ltd. All rights reserved.

Design, experimental and economic evaluation of a commercial-type solar dryer for production of high-quality hay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arinze, E.A.; Sokhansanj, S.; Schoenau, G.J.

1998-03-01

Design features, development, experimental functional performance and economic evaluation of an energy efficient solar energy dryer for commercial production of high-quality hay and processed forage products are presented. The solar hay dryer consists of an improved solar collector with selective coated aluminum absorber plate and spaced fins, and a drying shed connected to the collector by an insulated duct and having a perforated metal grate floor, swing-away plywood frames and polyethylene curtains for effectively sealing the hay stack, and a crawl space below the floor where a 3-hp in-line centrifugal fan is housed for air circulation by suction. In latemore » August and in early September, 1996, 160 small rectangular bales of alfalfa hay with about 25% bromegrass were successfully dried from 33% initial moisture content to 13%, and from 25% to 11% moisture in 4 and 3 days, respectively, under average weather conditions in Saskatoon, Saskatchewan, Canada. With about 18 m{sup 3}/min per tonne airflow, 10--15 C temperature rise above ambient was obtained during peak bright sunshine hours. Relatively high daily average collector efficiency of 76%, high drying effectiveness, drying uniformity, uniform air distribution and tight sealing of the stack were achieved which resulted in an attractive green color of hay, no mold growth on hay, and an overall system drying efficiency of about 79%. Compared to a conventional natural gas drying system or field-drying method, the payback period on extra investment costs recovered through drying cost savings of $3/t to $6/t or through over two times higher prices for high-quality hay produced by the solar drying system may be just one or two years, respectively.« less

Concentrating Solar Power Projects - Solar Electric Generating Station VIII

Science.gov Websites

: Harper Dry Lake, California (Mojave Desert) Owner(s): NextEra (50%) Technology: Parabolic trough Turbine City: Harper Dry Lake State: California County: San Bernardino Region: Mojave Desert Lat/Long Location

Concentrating Solar Power Projects - Solar Electric Generating Station IX |

Science.gov Websites

Station IX (SEGS IX) Country: United States Location: Harper Dry Lake, California (Mojave Desert) Owner(s : Parabolic trough Status: Operational Country: United States City: Harper Dry Lake State: California County

Cumulative ventilation air drying potential as an indication of dry mass content in wastewater sludge in a thin-layer solar drying facility

NASA Astrophysics Data System (ADS)

Krawczyk, Piotr

2013-12-01

Controlling low-temperature drying facilities which utilise nonprepared air is quite difficult, due to very large variability of ventilation air parameters - both in daily and seasonal cycles. The paper defines the concept of cumulative drying potential of ventilation air and presents experimental evidence that there is a relation between this parameter and condition of the dried matter (sewage sludge). Knowledge on current dry mass content in the dried matter (sewage sludge) provides new possibilities for controlling such systems. Experimental data analysed in the paper was collected in early 2012 during operation of a test solar drying facility in a sewage treatment plant in Błonie near Warsaw, Poland.

Drivers of solar radiation variability in the McMurdo Dry Valleys, Antarctica

USGS Publications Warehouse

Obryk, Maciej; Fountain, Andrew G.; Doran, Peter; Lyons, Berry; Eastman, Ryan

2018-01-01

Annually averaged solar radiation in the McMurdo Dry Valleys, Antarctica has varied by over 20 W m−2 during the past three decades; however, the drivers of this variability are unknown. Because small differences in radiation are important to water availability and ecosystem functioning in polar deserts, determining the causes are important to predictions of future desert processes. We examine the potential drivers of solar variability and systematically eliminate all but stratospheric sulfur dioxide. We argue that increases in stratospheric sulfur dioxide increase stratospheric aerosol optical depth and decrease solar intensity. Because of the polar location of the McMurdo Dry Valleys (77–78°S) and relatively long solar ray path through the stratosphere, terrestrial solar intensity is sensitive to small differences in stratospheric transmissivity. Important sources of sulfur dioxide include natural (wildfires and volcanic eruptions) and anthropogenic emission.

Numerical analysis on thermal energy storage device to improve the drying time of indirect type solar dryer

NASA Astrophysics Data System (ADS)

Yadav, Satyapal; Lingayat, Abhay Bhanudas; Chandramohan, V. P.; Raju, V. R. K.

2018-05-01

Thermal energy storage (TES) device that uses phase change material (PCM) in the field of indirect solar drying is economical due to its energy storage characteristics. In this work, a low-temperature latent heat TES device has been numerically analyzed for the application of solar drying of agricultural products in an indirect type solar dryer. Paraffin wax is used as a PCM material. The study has been performed on a single set of concentric tubes which consist of an inner copper tube and an outer plastic tube. A 2D geometry is created and computational fluid dynamics (CFD) simulations are performed using ANSYS Fluent 2015. The hot air coming from solar collector enters the copper tube and then the drying chamber to dry the sample. PCM material is placed in the outer plastic tube. It was found that the drying process can be continued up to 10.00 pm without further source of heating. At a given time, the melting fraction is increased during the heating process and solidification factor is increased during the cooling process while increasing the air flow velocities from 1 to 4 m/s, but 1 m/s is good for maintaining outlet temperature of air (T oa ) for a long time. Heat lost and gained by air was estimated. It was found that air flow velocity influenced the heat lost and gain by air.

Grapes ( Vitis vinifera) drying by semitransparent photovoltaic module (SPVM) integrated solar dryer: an experimental study

NASA Astrophysics Data System (ADS)

Tiwari, Sumit; Tiwari, G. N.

2018-06-01

In present research paper, semi-transparent photovoltaic module (SPVM) integrated greenhouse solar drying system has been used for grapes ( Vitis vinifera) drying. Based on hourly experimental information namely solar intensity, moisture evaporated, ambient air temperature, grape surface temperatures, relative humidity and greenhouse air temperature etc. heat and mass transfer coefficient for the SPVM drying system have been evaluated. It has been seen that the convective heat transfer coefficients for grapes found between 3.1-0.84 W/m2 K. Also, there is a fair agreement between theoretical and practical mass transfer (moisture evaporated) during drying of grapes with a correlation coefficient (r) and root mean square percentage deviation (e) of 0.88 and 11.56 respectively. Further, nonlinear regression procedure has been used to fit various drying models namely Henderson and Pabis model, Newton's model, and Page's model. From the analysis, it was found that Page's model is best fitted for grapes drying in SPV greenhouse as well as open sun drying. Further, net electrical energy, thermal energy and equivalent thermal energy were found to be 3.61, 17.66 and 27.15 kWh during six days of drying respectively.

Environmental and Economic Performance of Commercial-scale Solar Photovoltaic Systems: A Field Study of Complex Energy Systems at the Desert Research Institute (DRI)

NASA Astrophysics Data System (ADS)

Liu, X.

2014-12-01

Solar photovoltaic (PV) systems are being aggressively deployed at residential, commercial, and utility scales to complement power generation from conventional sources. This is motivated both by the desire to reduce carbon footprints and by policy-driven financial incentives. Although several life cycle analyses (LCA) have investigated environmental impacts and energy payback times of solar PV systems, most results are based on hypothetical systems rather than actual, deployed systems that can provide measured performance data. Over the past five years, Desert Research Institute (DRI) in Nevada has installed eight solar PV systems of scales from 3 to 1000 kW, the sum of which supply approximately 40% of the total power use at DRI's Reno and Las Vegas campuses. The goal of this work is to explore greenhouse gas (GHG) impacts and examine the economic performance of DRI's PV systems by developing and applying a comprehensive LCA and techno-economic (TEA) model. This model is built using data appropriate for each type of panel used in the DRI systems. Power output is modeled using the National Renewable Energy Laboratory (NREL) model PVWatts. The performance of PVWatts is verified by the actual measurements from DRI's PV systems. Several environmental and economic metrics are quantified for the DRI systems, including life cycle GHG emissions and energy return. GHG results are compared with Nevada grid-based electricity. Initial results indicate that DRI's solar-derived electricity offers clear GHG benefits compared to conventional grid electricity. DRI's eight systems have GHG intensity values of 29-56 gCO2e/kWh, as compared to the GHG intensity of 212 gCO2e/kWh of national average grid power. The major source of impacts (82-92% of the total) is the upstream life cycle burden of manufacturing PV panels, which are made of either mono-crystalline or multi-crystalline silicon. Given the same type of PV panel, GHG intensity decreases as the scale of the system increases. Energy payback times of DRI's solar PV systems range from 0.5 to 1.5 years. The cost payback time for the DRI PV systems and the cost per ton of CO2 avoided by replacing Nevada-specific electrical power will be determined. The sensitivity of these environmental and economic impacts with respect to specific model parameters is being investigated.

Solar powered dehumidifier apparatus

DOEpatents

Jebens, Robert W.

1980-12-30

A thermally insulated light transmitting housing forms a chamber containing a desiccant and having a first gas port open to the ambient and a second gas port connected by a two way valve to a volume to be dried. Solar energy transmitted through the housing heats and dries the desiccant. The increased air pressure due to the heating of the volume to be dried causes the air from the volume to be expelled through the valve into the chamber. The desiccant is then cooled by shielding it from solar energy before the volume cools thereby increasing its moisture absorbing capacity. Then the volume is allowed to cool drawing dehumidified air through the desiccant and the valve into the volume to be dried. This cycle is then repeated.

Baseline performance of solar collectors for NASA Langley solar building test facility

NASA Technical Reports Server (NTRS)

Knoll, R. H.; Johnson, S. M.

1977-01-01

The solar collector field contains seven collector designs. Before operation in the field, the experimental performances (thermal efficiencies) of the seven collector designs were measured in an indoor solar simulator. The resulting data provided a baseline for later comparison with actual field test data. The simulator test results are presented for the collectors as received, and after several weeks of outdoor exposure with no coolant (dry operation). Six of the seven collector designs tested showed substantial reductions in thermal efficiency after dry operation.

Impacts of tilling and covering treatments on the biosolids solar drying conversion from Class B to Class A

USDA-ARS?s Scientific Manuscript database

The objective of this study was to evaluate the effects of tillage and cover treatments of solar drying on the conversion of Class B treated sewage sludge to a Class A product. The experiments were performed over two years at Green Valley, Arizona in steel-constructed sand-filled drying beds of 1.0m...

Solar drying and organoleptic characteristics of two tropical African fish species using improved low-cost solar driers.

PubMed

Mustapha, Moshood K; Ajibola, Taiye B; Salako, Abdulbashir F; Ademola, Sunmola K

2014-05-01

This study was done to evaluate the drying performance, efficiency, and effectiveness of five different types of improved low-cost solar driers in terms of moisture loss from two tropical African fish species Clarias gariepinus (African sharp tooth catfish) and Oreochromis niloticus (Nile tilapia) and testing the organoleptic characteristics of the dried samples. The driers used were made from plastic, aluminum, glass, glass with black igneous stone, and mosquito net, with traditional direct open-sun drying as a control. A significant (P < 0.05) decrease in weight resulting from moisture loss in the two fish species was observed in all the driers, with the highest reduction occurring in the glass drier containing black stone. The rate of weight loss was faster in the first 4 days of drying with black stone-inserted glass drier showing the fastest drying rate with a constant weight in C. gariepinus attained on the 11th day and in O. niloticus on the eighth day. The slowest drier was plastic where a constant weight of the species were recorded on and 13th day and 11th day, respectively. Volunteers were used to assess the organoleptic characteristics of the dried samples and they showed lowest acceptability for the open-sun drying, while samples from the glass drier containing black stone had the highest acceptability in terms of the taste, flavor, appearance, texture, odor, palatability, and shelf-life. The low-cost solar driers were effective found in removing water from the fish resulting in significant loss of weight and moisture. The highest drying time, efficient performance, drying effectiveness, and high acceptability of the organoleptic parameters of the dried products from the black stone-inserted glass drier were due to the ability of the glass and the black stone to retain, transmit, and radiate heat to the fish sample all the time (day and night). These low-cost driers are simple to construct, materials for its construction readily available, easy to maintain and operate, hygienic in use, reliable, effective, occupies less area, dry products faster with increased shelf-life, save man-hour, user-friendly, use renewable energy, protect the drying samples from filthiness, wetness, and invasion by pests, insects, and microbes, with well-dried, high-quality, and better preserved final products. The adoption and use any of these low-cost solar driers by artisanal fishermen and general household in sub-Saharan Africa will not only help in reducing post catch losses, but also ensure food safety and security as there is abundant solar energy in these sub-Saharan African tropical countries for the operation of the driers.

Solar energy dryer kinetics using flat-plate finned collector and forced convection for potato drying

NASA Astrophysics Data System (ADS)

Batubara, Fatimah; Misran, Erni; Dina, Sari Farah; Heppy

2017-06-01

Research on potato drying using the indirect solar dryer with flat-plate finned collector and forced convection has been done. The research was conducted at the outdoor field of Laboratory of Institute for Research and Standardization of Industry on June 14th-23rd, 2016 from 9:00 am to 4:00 pm. This research aims to obtain the drying kinetics model of potato (Solanumtuberosum L.) using an indirect solar dryer's (ISD) with flat plate-finned collector and forced convection. The result will be compared to the open sun drying (OSD) method. Weather conditions during the drying process took place as follows; surrounding air temperature was in the range 27 to 34.7 °C, relative humidity (RH) 29.5 to 61.0% and the intensity of solar radiation 105.6 to 863.1 Watt/m2. The dried potato thicknesses were 1.0 cm, 1.5 cm and 2.0 cm, with the average initial water content of 76.46%. The average temperature in the collector chamber ranged from 42.2 to 57.4 °C and the drying chamber was at 46.2 °C. The best drying result was obtained from a sample size of 1 cm thickness using the IDS method with an average drying rate of 0.018 kg H2O per kg dry-weight.hour and the water content was constant at 5.02% in 21 hours of drying time. The most suitable kinetics model is Page model, equation MR = exp (-0.049 t1,336) for 1.0 cm thickness, exp (-0.066 t1,222) for 1.5 cm thickness and exp (-0.049 t1,221) for 2.0 cm thickness. The quality of potato drying using ISD method is better than using OSD which can be seen from the color produced.

Evaluation of solar sludge drying alternatives by costs and area requirements.

PubMed

Kurt, Mayıs; Aksoy, Ayşegül; Sanin, F Dilek

2015-10-01

Thermal drying is a common method to reach above 90% dry solids content (DS) in sludge. However, thermal drying requires high amount of energy and can be expensive. A greenhouse solar dryer (GSD) can be a cost-effective substitute if the drying performance, which is typically 70% DS, can be increased by additional heat. In this study feasibility of GSD supported with solar panels is evaluated as an alternative to thermal dryers to reach 90% DS. Evaluations are based on capital and O&M costs as well as area requirements for 37 wastewater treatment plants (WWTPs) with various sludge production rates. Costs for the supported GSD system are compared to that of conventional and co-generation thermal dryers. To calculate the optimal costs associated with the drying system, an optimization model was developed in which area limitation was a constraint. Results showed that total cost was minimum when the DS in the GSD (DS(m,i)) was equal to the maximum attainable value (70% DS). On average, 58% of the total cost and 38% of total required area were associated with the GSD. Variations in costs for 37 WWTPs were due to differences in initial DS (DS(i,i)) and sludge production rates, indicating the importance of dewatering to lower drying costs. For large plants, GSD supported with solar panels provided savings in total costs especially in long term when compared to conventional and co-generation thermal dryers. Copyright © 2015 Elsevier Ltd. All rights reserved.

Textile drying using solarized can dryers to demonstrate the application of solar energy to industrial drying or dehydration processes, Phase II. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mitchell, P.D.; Beesing, M.E.; Bessler, G.L.

This program has resulted in the installation of a solar energy collection system for providing process heat to a textile drying process. The solar collection subsystem uses 700 square meters (7500 square feet) of parabolic trough, single-axis tracking, concentrating collectors to heat water in a high temperature water (HTW) loop. The solar collectors nominally generate 193/sup 0/C (380/sup 0/F) water with the HTW loop at 1.9 x 10/sup 6/ Pa (275 psi). A steam generator is fueled with the HTW and produces 450 kg/hour (1000 pounds per hour) of process steam at the nominal design point conditions. The solar-generated processmore » steam is at 0.5 x 10/sup 6/ Pa (75 psi) and 160/sup 0/C (321/sup 0/F). It is predicted that the solar energy system will provide 1.2 x 10/sup 6/ MJ/year (1.1 x 10/sup 9/ Btu/year) to the process. This is 46 percent of the direct isolation available to the collector field during the operational hours (300 days/year of the Fairfax mill. The process being solarized is textile drying using can dryers. The can dryers are part of a slashing operation in a WestPoint Pepperell mill in Fairfax, Alabama. Over 50 percent of all woven goods are processed through slashers and dried on can dryers. The collectors were fabricated by Honeywell at a pilot production facility in Minneapolis, Minnesota, under a 3000-square-meter (32,000-square-foot) production run. The collectors and other system components were installed at the site by the Bahnson Service Company and their subcontractors, acting as the project general contractor. System checkout and start-up was conducted. Preliminary system performance was determined from data collected during start-up. System design, fabrication and installation, data analysis, operation and maintenance procedures, and specifications and drawings are presented.« less

Scalable, "Dip-and-Dry" Fabrication of a Wide-Angle Plasmonic Selective Absorber for High-Efficiency Solar-Thermal Energy Conversion.

PubMed

Mandal, Jyotirmoy; Wang, Derek; Overvig, Adam C; Shi, Norman N; Paley, Daniel; Zangiabadi, Amirali; Cheng, Qian; Barmak, Katayun; Yu, Nanfang; Yang, Yuan

2017-11-01

A galvanic-displacement-reaction-based, room-temperature "dip-and-dry" technique is demonstrated for fabricating selectively solar-absorbing plasmonic-nanoparticle-coated foils (PNFs). The technique, which allows for facile tuning of the PNFs' spectral reflectance to suit different radiative and thermal environments, yields PNFs which exhibit excellent, wide-angle solar absorptance (0.96 at 15°, to 0.97 at 35°, to 0.79 at 80°), and low hemispherical thermal emittance (0.10) without the aid of antireflection coatings. The thermal emittance is on par with those of notable selective solar absorbers (SSAs) in the literature, while the wide-angle solar absorptance surpasses those of previously reported SSAs with comparable optical selectivities. In addition, the PNFs show promising mechanical and thermal stabilities at temperatures of up to 200 °C. Along with the performance of the PNFs, the simplicity, inexpensiveness, and environmental friendliness of the "dip-and-dry" technique makes it an appealing alternative to current methods for fabricating selective solar absorbers. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The effect of dry shear aligning of nanotube thin films on the photovoltaic performance of carbon nanotube-silicon solar cells.

PubMed

Stolz, Benedikt W; Tune, Daniel D; Flavel, Benjamin S

2016-01-01

Recent results in the field of carbon nanotube-silicon solar cells have suggested that the best performance is obtained when the nanotube film provides good coverage of the silicon surface and when the nanotubes in the film are aligned parallel to the surface. The recently developed process of dry shear aligning - in which shear force is applied to the surface of carbon nanotube thin films in the dry state, has been shown to yield nanotube films that are very flat and in which the surface nanotubes are very well aligned in the direction of shear. It is thus reasonable to expect that nanotube films subjected to dry shear aligning should outperform otherwise identical films formed by other processes. In this work, the fabrication and characterisation of carbon nanotube-silicon solar cells using such films is reported, and the photovoltaic performance of devices produced with and without dry shear aligning is compared.

The effect of dry shear aligning of nanotube thin films on the photovoltaic performance of carbon nanotube–silicon solar cells

PubMed Central

Stolz, Benedikt W; Tune, Daniel D

2016-01-01

Summary Recent results in the field of carbon nanotube–silicon solar cells have suggested that the best performance is obtained when the nanotube film provides good coverage of the silicon surface and when the nanotubes in the film are aligned parallel to the surface. The recently developed process of dry shear aligning – in which shear force is applied to the surface of carbon nanotube thin films in the dry state, has been shown to yield nanotube films that are very flat and in which the surface nanotubes are very well aligned in the direction of shear. It is thus reasonable to expect that nanotube films subjected to dry shear aligning should outperform otherwise identical films formed by other processes. In this work, the fabrication and characterisation of carbon nanotube–silicon solar cells using such films is reported, and the photovoltaic performance of devices produced with and without dry shear aligning is compared. PMID:27826524

Performance evaluation of two black nickel and two black chrome solar collectors

NASA Technical Reports Server (NTRS)

Losey, R.

1977-01-01

The test program was based on the evaluation of four unique solar collectors described below: (1) black nickel collector surface with a desiccant drying bed, (2) black nickel collector surface without a desiccant drying bed, (3) black chrome collector surface with a dessicant drying bed, and (4) black chrome collector surface without a desiccant drying bed. The test program included three distinct phases: Initial performance evaluation, natural environmental aging, and post-aging performance evaluation. Results of Phase III testing conclusively indicated a higher normalized efficiency for Black Chrome surfaces when compared to Black Nickel.

The Effect of Operating Conditions on Drying Characteristics and Quality of Ginger (Zingiber Officinale Roscoe) Using Combination of Solar Energy-Molecular Sieve Drying System

NASA Astrophysics Data System (ADS)

Hasibuan, R.; Zamzami, M. A.

2017-03-01

Ginger (Zingiber officinale Roscoe) is an agricultural product that can be used as beverages and snacks, and especially for traditional medicines. One of the important stages in the processing of ginger is drying. The drying process intended to reduce the water content of 85-90% to 8-10%, making it safe from the influence of fungi or insecticide. During the drying takes place, the main ingredient contained in ginger is homologous ketone phenolic known as gingerol are chemically unstable at high temperatures, for the drying technology is an important factor in maintaining the active ingredient (gingerol) which is in ginger. The combination of solar energy and molecular sieve dryer that are used in the research is capable of operating 24 hours. The purpose of this research is to study the effect of operating conditions (in this case the air velocity) toward the drying characteristics and the quality of dried ginger using the combination of solar energy and molecular sieve dryer. Drying system consist of three main parts which is: desiccator, solar collector, and the drying chamber. To record data changes in the mass of the sample, a load cell mounted in the drying chamber, and then connected to the automated data recording system using a USB data cable. All data of temperature and RH inside the dryer box and the change of samples mass recorded during the drying process takes place and the result is stored in the form of Microsoft Excel. The results obtained, shows that the air velocity is influencing the moisture content and ginger drying rate, where the moisture content equilibrium of ginger for the air velocity of 1.3 m/s was obtained on drying time of 360 minutes and moisture content of 2.8%, at 1.0 m/s was obtained on drying time of 300 minutes and moisture content of 1.4%, at 0, 8 m/s was obtained at 420 minutes drying time and the moisture content is 2.0%. The drying characteristics shows that there are two drying periods, which is: the increasing drying rate, and the falling drying rate, while the constant drying rate is not visible. The result of ginger quality shows that there are no significant changes in the organoleptic analysis, the ash content is about 7.52-7.94% and the oil content is 0.79-0.83%.

Evaluation of Pathogen Removal in a Solar Sludge Drying Facility Using Microbial Indicators

PubMed Central

Shanahan, Emily F.; Roiko, Anne; Tindale, Neil W.; Thomas, Michael P.; Walpole, Ronald; Kurtböke, D. İpek

2010-01-01

South East Queensland is one of the fastest growing regions in Australia with a correspondingly rapid increase in sewage production. In response, local councils are investing in more effective and sustainable options for the treatment and reuse of domestic and industrial effluents. A novel, evaporative solar dryer system has been installed on the Sunshine Coast to convert sewage sludge into a drier, usable form of biosolids through solar radiation exposure resulting in decreased moisture concentration and pathogen reduction. Solar-dried biosolids were analyzed for selected pathogenic microbial, metal and organic contaminants at the end of different drying cycles in a collaborative study conducted with the Regional Council. Although fecal coliforms were found to be present, enteroviruses, parasites, E. coli, and Salmonella sp. were not detected in the final product. However, elevated levels of zinc and copper were still present which restricted public use of the biosolids. Dilution of the dried biosolids with green waste as well as composting of the biosolids is likely to lead to the production of an environmentally safe, Class A end-product. PMID:20616991

Optimum dry-cooling sub-systems for a solar air conditioner

NASA Technical Reports Server (NTRS)

Chen, J. L. S.; Namkoong, D.

1978-01-01

Dry-cooling sub-systems for residential solar powered Rankine compression air conditioners were economically optimized and compared with the cost of a wet cooling tower. Results in terms of yearly incremental busbar cost due to the use of dry-cooling were presented for Philadelphia and Miami. With input data corresponding to local weather, energy rate and capital costs, condenser surface designs and performance, the computerized optimization program yields design specifications of the sub-system which has the lowest annual incremental cost.

Influence of factors on the drying of cassava in a solar simulator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Njie, D.N.; Rumsey, T.R.

1997-03-01

In tropical countries, sun drying is still the most popular method used for processing root and tuber crops like cassava and yam. Relatively very little has been done on studying the kinetics of sun drying a bed of chips of cassava and similar crops, but this information is invaluable in finding options for reducing drying time and costs, and increasing tonnage produced. This project studied some factors that have an effect on the sun drying rate of cassava chips. The factors were ambient temperature, relative humidity, radiation intensity, air velocity, and loading density. A solar simulation chamber was constructed somore » that drying could be achieved under controllable conditions similar to those obtained in sun drying. Experiments carried out in the simulator revealed that temperature had the most significant effect on drying rate, followed by air velocity, and radiation intensity. Regression equations were developed relating the drying rate with the factors studied.« less

Simulation of Solar Heat Pump Dryer Directly Driven by Photovoltaic Panels

NASA Astrophysics Data System (ADS)

Houhou, H.; Yuan, W.; Wang, G.

2017-05-01

This paper investigates a new type of solar heat pump dryer directly driven by photovoltaic panels. In order to design this system, a mathematical model has been established describing the whole drying process, including models of key components and phenomena of heat and mass transfer at the product layer and the air. The results of simulation at different drying air temperatures and velocities have been calculated and it indicate that the temperature of drying air is crucial external parameter compared to the velocity, with the increase of drying temperature from 45°C to 55°C, the product moisture content (Kg water/Kg dry product) decreased from 0.75 Kg/Kg to 0.3 Kg/Kg.

Two-dimensional CFD modeling of the heat and mass transfer process during sewage sludge drying in a solar dryer

NASA Astrophysics Data System (ADS)

Krawczyk, Piotr; Badyda, Krzysztof

2011-12-01

The paper presents key assumptions of the mathematical model which describes heat and mass transfer phenomena in a solar sewage drying process, as well as techniques used for solving this model with the Fluent computational fluid dynamics (CFD) software. Special attention was paid to implementation of boundary conditions on the sludge surface, which is a physical boundary between the gaseous phase - air, and solid phase - dried matter. Those conditions allow to model heat and mass transfer between the media during first and second drying stages. Selection of the computational geometry is also discussed - it is a fragment of the entire drying facility. Selected modelling results are presented in the final part of the paper.

Effect of pretreatment on rehydration, colour and nanoindentation properties of potato cylinders dried using a mixed-mode solar dryer.

PubMed

Dhalsamant, Kshanaprava; Tripathy, Punyadarshini P; Shrivastava, Shanker L

2017-08-01

Desirable quality estimation is an important consumer driver for wider acceptability of mixed-mode solar drying of potatoes in food industries. The aim of this study is to characterise rehydration, colour, texture, nanoindentaion and microstructure of dried potato samples and to establish the influence of pre-drying treatment on the above qualities. The water absorption capacity and rehydration ability of solar dried potato were significantly influenced by pretreatment followed by rehydration temperature and sample diameter. The redness index (a*) of pretreated dried samples was lower with simultaneous higher value of yellowness index (b*), chroma (C*) and hue angle (h*). Also, the average nanohardness (H) of pretreated samples increased significantly by 22.64% compared to that of untreated samples. The average reduced modulus (E r ) and Young's modulus (E s ) of dried potato samples were 1.865 GPa and 1.403 GPa, respectively. Moreover, creep displacement of 43.27 nm was traced in the untreated potato samples during a 20 s dwell time under a constant load of 200 µN in the nanoindentation test. Micrographs revealed more uniform pore spaces in pretreated samples. Pretreated, thinner potato samples achieved better quality dried products in terms of rehydration, colour, texture and nanohardness indices with significantly improved microstructure and creep resistance properties. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Solar thermal drum drying performance of prune and tomato pomaces

USDA-ARS?s Scientific Manuscript database

Fruit and vegetable pomaces are co-products of the food processing industry; they are underutilized in part because their high water activity (aw) renders them unstable. Drum drying is one method that can dry/stabilize pomaces, but current drum drying methods utilize conventional, high-environmental...

Concentrating Solar Power Projects - Redstone Solar Thermal Power Plant |

Science.gov Websites

Concentrating Solar Power | NREL Redstone Solar Thermal Power Plant Status Date: September 8 , 2016 Project Overview Project Name: Redstone Solar Thermal Power Plant Country: South Africa Location ): 100.0 MW Turbine Capacity (Net): 100.0 MW Cooling Method: Dry cooling Thermal Storage Storage Type: 2

Comparison of Selected Metals Content in Cambodian Striped Snakehead Fish (Channa striata) Using Solar Drying System and Open Sun Drying

PubMed Central

Abu Bakar, Nur Faizah; Fudholi, Ahmad; Ruslan, Mohd Hafidz; Saroeun, Im

2015-01-01

The content of 12 elements in Cambodian dried striped snakehead fish was determined using inductively coupled plasma mass spectrometry. The present study compares the level of the trace toxic metals and nutritional trace elements in the fish processed using solar drying system (SDS) and open sun drying (OSD). The skin of SDS fish has lower level of As, Pb, and Cd compared to the OSD sample. As such, the flesh of the fish accumulated higher amount of toxic metals during OSD compared to SDS. However, arsenic was detected in both samples within the safe limit. The nutritional elements (Fe, Mn, Mg, Se, Mo, Cu, Ni, and Cr) were higher in the skin sample SDS fish compared to OSD fish. These beneficial metals were not accumulated in the flesh sample SDS fish demonstrating lower level compared to drying under conventional system. The reddish coloration of the SDS fish was due to the presence of high Cu content in both the skin and flesh samples which possibly account for no mold formation 5 days after packaging. As conclusion, drying of Cambodian C. striata using solar-assisted system has proven higher content of the nutritious elements compared to using the conventional system despite only slight difference in the toxic metals level between the two systems. PMID:25688274

Drying of vanilla pods using a greenhouse effect solar dryer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abdullah, K.; Mursalim

This paper describes the basic design of the GHE solar dryer and evaluates the performance of the dryer when used to dry vanilla pods. From laboratory test results it was indicted that the average drying time for vanilla pods was between 49 to 53.5 hrs. For the case of heating augmentation using coal briquette stoves. The total amount of coal briquettes used to produce drying air temperature between 33 C to 65 C and RH of about 34% during day time was 61 kg equivalent to 6.1 kW heating rate and the average electric energy usage of 36.5 kWh, respectively.more » Quality test results indicated that the dried products were of grade IA of the export quality standard with vaniline content of 2.36%.« less

Implications of drying temperature and humidity on the drying kinetics of seaweed

NASA Astrophysics Data System (ADS)

Ali, Majid Khan Majahar; Fudholi, Ahmad; Muthuvalu, M. S.; Sulaiman, Jumat; Yasir, Suhaimi Md

2017-11-01

A Low Temperature and Humidity Chamber Test tested in the Solar Energy Laboratory, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Selangor, Malaysia. Experiments are attempted to study the effect of drying air temperature and humidity on the drying kinetics of seaweed Kappaphycus species Striatum besides to develop a model to estimate the drying curves. Simple method using a excel software is used in the analysis of raw data obtained from the drying experiment. The values of the parameters a, n and the constant k for the models are determined using a plot of curve drying models. Three different drying models are compared with experiment data seaweed drying at 30, 40, 50 and 60°C and relative humidity 20, 30 and 40% for seaweed. The higher drying temperatures and low relative humidity effects the moisture content that will be rapidly reduced. The most suitable model is selected to best describe the drying behavior of seaweed. The values of the coefficient of determination (R2), mean bias error (MBE) and root mean square error (RMSE) are used to determine the goodness or the quality of the fit. The Page model is showed a better fit to drying seaweed. The results from this study crucial for solar dryer development on pilot scale in Malaysia.

Process and formulation effects on solar thermal drum dried prune pomace

USDA-ARS?s Scientific Manuscript database

The processing of dried plums into prune juice and concentrate yields prune pomace as a coproduct; the pomace could potentially be utilized as a food ingredient but requires stabilization for long-term storage. Drum drying is one method that could be used to dry and stabilize prune pomace, and a dru...

Energy-efficient regenerative liquid desiccant drying process

DOEpatents

Ko, Suk M.; Grodzka, Philomena G.; McCormick, Paul O.

1980-01-01

This invention relates to the use of desiccants in conjunction with an open oop drying cycle and a closed loop drying cycle to reclaim the energy expended in vaporizing moisture in harvested crops. In the closed loop cycle, the drying air is brought into contact with a desiccant after it exits the crop drying bin. Water vapor in the moist air is absorbed by the desiccant, thus reducing the relative humidity of the air. The air is then heated by the used desiccant and returned to the crop bin. During the open loop drying cycle the used desiccant is heated (either fossil or solar energy heat sources may be used) and regenerated at high temperature, driving water vapor from the desiccant. This water vapor is condensed and used to preheat the dilute (wet) desiccant before heat is added from the external source (fossil or solar). The latent heat of vaporization of the moisture removed from the desiccant is reclaimed in this manner. The sensible heat of the regenerated desiccant is utilized in the open loop drying cycle. Also, closed cycle operation implies that no net energy is expended in heating drying air.

Effect of Tube Diameter on The Design of Heat Exchanger in Solar Drying system

NASA Astrophysics Data System (ADS)

Husham Abdulmalek, Shaymaa; Khalaji Assadi, Morteza; Al-Kayiem, Hussain H.; Gitan, Ali Ahmed

2018-03-01

The drying of agriculture product consumes a huge fossil fuel rates that demand to find an alternative source of sustainable environmental friendly energy such as solar energy. This work presents the difference between using solar heat source and electrical heater in terms of design aspect. A circular-finned tube bank heat exchanger is considered against an electrical heater used as a heat generator to regenerate silica gel in solar assisted desiccant drying system. The impact of tube diameter on the heat transfer area was investigated for both the heat exchanger and the electrical heater. The fin performance was investigated by determining fin effectiveness and fin efficiency. A mathematical model was developed using MATLAB to describe the forced convection heat transfer between hot water supplied by evacuated solar collector with 70 °C and ambient air flow over heat exchanger finned tubes. The results revealed that the increasing of tube diameter augments the heat transfer area of both heat exchanger and electrical heater. The highest of fin efficiency was around 0.745 and the lowest was around 0.687 while the fin effectiveness was found to be around 0.998.

A field survey on coffee beans drying methods of Indonesian small holder farmers

NASA Astrophysics Data System (ADS)

Siagian, Parulian; Setyawan, Eko Y.; Gultom, Tumiur; Napitupulu, Farel H.; Ambarita, Himsar

2017-09-01

Drying agricultural product is a post-harvest process that consumes significant energy. It can affect the quality of the product. This paper deals with literature review and field survey of drying methods of coffee beans of Indonesia farmers. The objective is to supply the necessary information on developing continuous solar drier. The results show that intermittent characteristic of sun drying results in a better quality of coffee beans in comparison with constant convective drying. In order to use energy efficiently, the drying process should be divided into several stages. In the first stage when the moist content is high, higher drying air temperature is more effective. After this step, where the moist content is low, lower drying air temperature is better. The field survey of drying coffee beans in Sumatera Utara province reveals that the used drying process is very traditional. It can be divided into two modes and depend on the coffee beans type. The Arabica coffee is firstly fermented and dried to moisture content of 80% using sun drying method, then followed by Green House model of drying up to moisture content about 12%. The latter typically spends 3 days of drying time. On the other hand, The Robusta coffee is dried by exposing to the sun directly without any treatment. After the coffee beans dried follow by peeled process. These findings can be considered to develop a continuous solar drying that suitable for coffee beans drying.

Crop drying by indirect active hybrid solar - Electrical dryer in the eastern Algerian Septentrional Sahara

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boughali, S.; Bouchekima, B.; Mennouche, D.

2009-12-15

In the present work, a new specific prototype of an indirect active hybrid solar-electrical dryer for agricultural products was constructed and investigated at LENREZA Laboratory, University of Ouargla (Algerian Sahara). In the new configuration of air drying passage; the study was done in a somewhat high range of mass flow rate between 0.04 and 0.08 kg/m{sup 2} s a range not properly investigated by most researchers. Experimental tests with and without load were performed in winter season in order to study the thermal behavior of the dryer and the effect of high air masse flow on the collector and systemmore » drying efficiency. The fraction of electrical and solar energy contribution versus air mass flow rate was investigated. Slice tomato was studied with different temperatures and velocities of drying air in order to study the influence of these parameters on the removal moisture content from the product and on the kinetics drying and also to determine their suitable values. Many different thin layer mathematical drying models were compared according to their coefficient of determination (R{sup 2}) and reduced chi square ({chi}{sup 2}) to estimate experimental drying curves. The Middli model in this condition proved to be the best for predicting drying behavior of tomato slice with (R{sup 2} = 0.9995, {chi}{sup 2} = 0.0001). Finally an economic evaluation was calculated using the criterion of payback period which is found very small 1.27 years compared to the life of the dryer 15 years. (author)« less

Riverside East Solar Energy Zone (SEZ) - California

Science.gov Websites

Los Mogotes East Nevada Amargosa Valley Dry Lake Dry Lake Valley North Gold Point Millers New Mexico Pavement Cultural Gravel Bench I 10 Wiley Well Road South Wiley Well Rest Stop Ford Dry Lake Get Adobe there are also dry lake beds, sandy areas, and dry washes with ironwood and other trees. Some areas are

20% Efficient Zn0.9Mg0.1O:Al/Zn0.8Mg0.2O/Cu(In,Ga)(S,Se)2 Solar Cell Prepared by All-Dry Process through a Combination of Heat-Light-Soaking and Light-Soaking Processes.

PubMed

Chantana, Jakapan; Kato, Takuya; Sugimoto, Hiroki; Minemoto, Takashi

2018-04-04

Development of Cd-free Cu(In,Ga)(S,Se) 2 (CIGSSe)-based thin-film solar cells fabricated by an all-dry process is intriguing to minimize optical loss at a wavelength shorter than 520 nm owing to absorption of the CdS buffer layer and to be easily integrated into an in-line process for cost reduction. Cd-free CIGSSe solar cells are therefore prepared by the all-dry process with a structure of Zn 0.9 Mg 0.1 O:Al/Zn 0.8 Mg 0.2 O/CIGSSe/Mo/glass. It is demonstrated that Zn 0.8 Mg 0.2 O and Zn 0.9 Mg 0.1 O:Al are appropriate as buffer and transparent conductive oxide layers with large optical band gap energy values of 3.75 and 3.80 eV, respectively. The conversion efficiency (η) of the Cd-free CIGSSe solar cell without K-treatment is consequently increased to 18.1%. To further increase the η, the Cd-free CIGSSe solar cell with K-treatment is next fabricated and followed by posttreatment called the heat-light-soaking (HLS) + light-soaking (LS) process, including HLS at 110 °C followed by LS under AM 1.5G illumination. It is disclosed that the HLS + LS process gives rise to not only the enhancement of carrier density but also the decrease in the carrier recombination rate at the buffer/absorber interface. Ultimately, the η of the Cd-free CIGSSe solar cell with K-treatment prepared by the all-dry process is enhanced to the level of 20.0%.

Relationship between a solar drying model of red pepper and the kinetics of pure water evaporation (2)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Passamai, V.; Saravia, L.

1997-05-01

In part one, a simple drying model of red pepper related to water evaporation was developed. In this second part the drying model is applied by means of related experiments. Both laboratory and open air drying experiments were carried out to validate the model and simulation results are presented.

40 CFR 86.162-00 - Approval of alternative air conditioning test simulations and descriptions of AC1 and AC2.

Code of Federal Regulations, 2012 CFR

2012-07-01

... power requirements to roadload dynamometer requirements. AC2 simulates, in standard test cell ambient...)(i) (A) and (B) are replaced with 76 °F and 50 grains of water/pound of dry air and the solar heat...)(5)(i) (A) and (B) are replaced with 76 °F and 50 grains of water/pound of dry air and the solar heat...

40 CFR 86.162-00 - Approval of alternative air conditioning test simulations and descriptions of AC1 and AC2.

Code of Federal Regulations, 2013 CFR

2013-07-01

... power requirements to roadload dynamometer requirements. AC2 simulates, in standard test cell ambient...)(i) (A) and (B) are replaced with 76 °F and 50 grains of water/pound of dry air and the solar heat...)(5)(i) (A) and (B) are replaced with 76 °F and 50 grains of water/pound of dry air and the solar heat...

The solar-coffee connection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wright, G.

2000-04-01

Coffee connoisseurs, when they quaff a cup of coffee or enjoy a jug of joe, don't generally consider the costs to the environment of their favorite beverage. But the fact is that traditional coffee production is hard on the environment, exacting a toll on the native forests and waterways of Central America and on the migratory birds of the western hemisphere. Coffee growing is the second greatest cause of rainforest destruction after cattle ranching, because a lot of trees are cut down to dry the freshly-picked coffee crop. But espresso-sipping environmentalists and an eco-conscious Joe Public can take comfort inmore » a promising new connection between solar energy and rainforest-friendly coffee--solar-dried coffee. And they can take pleasure in it too, because solar-dried coffee, according to virtually everyone who tries it, is the best-tasting coffee made. Considering that coffee is the second most-traded commodity next to oil, and the second most popular beverage in the world next to water, consumed by billions of people, any new process that reduces the environmental damage occasioned by coffee-growing and processing is significant.« less

Effects of processing methods on composition and functionality of volatile components isolated from immature fruits of atemoya.

PubMed

Liu, Tai-Ti; Chao, Louis Kuo-Ping; Peng, Chi-Wei; Yang, Tsung-Shi

2016-07-01

Atemoya is one of the most important commercial fruits of the family Annonaceae. The immature fruits of atemoya amply produced from a fruit-thinning process is normally regarded as waste and discarded. This research aimed at studying antimicrobial, antioxidant, and anti-inflammatory activities of the essential oil (EO) isolated from the immature fruits to explore its potential application. The fruits were subjected to different drying methods: solar drying (SD), oven drying at 30°C (OD-30), and at 50°C (OD-50). The oven drying method gave a higher EO yield than the solar drying method. Spathulenol was the largest compound in the EO after the drying process. Antimicrobial effect was not affected by the different drying methods. Antioxidant activity of the EO was measured by DPPH, nitric oxide, and reducing power methods. The EOOD-50 exhibited a stronger antioxidant activity than EOSD and EOOD-30. The EO also showed an anti-inflammatory activity in a cell model. Copyright © 2016. Published by Elsevier Ltd.

Solar hydrogen production: renewable hydrogen production by dry fuel reforming

NASA Astrophysics Data System (ADS)

Bakos, Jamie; Miyamoto, Henry K.

2006-09-01

SHEC LABS - Solar Hydrogen Energy Corporation constructed a pilot-plant to demonstrate a Dry Fuel Reforming (DFR) system that is heated primarily by sunlight focusing-mirrors. The pilot-plant consists of: 1) a solar mirror array and solar concentrator and shutter system; and 2) two thermo-catalytic reactors to convert Methane, Carbon Dioxide, and Water into Hydrogen. Results from the pilot study show that solar Hydrogen generation is feasible and cost-competitive with traditional Hydrogen production. More than 95% of Hydrogen commercially produced today is by the Steam Methane Reformation (SMR) of natural gas, a process that liberates Carbon Dioxide to the atmosphere. The SMR process provides a net energy loss of 30 to 35% when converting from Methane to Hydrogen. Solar Hydrogen production provides a 14% net energy gain when converting Methane into Hydrogen since the energy used to drive the process is from the sun. The environmental benefits of generating Hydrogen using renewable energy include significant greenhouse gas and criteria air contaminant reductions.

The Effect of Elevated Ozone Concentrations with Varying Shading on Dry Matter Loss in a Winter Wheat-Producing Region in China.

PubMed

Xu, Jingxin; Zheng, Youfei; He, Yuhong; Wu, Rongjun; Mai, Boru; Kang, Hanqing

2016-01-01

Surface-level ozone pollution causes crop production loss by directly reducing healthy green leaf area available for carbon fixation. Ozone and its precursors also affect crop photosynthesis indirectly by decreasing solar irradiance. Pollutants are reported to have become even more severe in Eastern China over the last ten years. In this study, we investigated the effect of a combination of elevated ozone concentrations and reduced solar irradiance on a popular winter wheat Yangmai13 (Triticum aestivum L.) at field and regional levels in China. Winter wheat was grown in artificial shading and open-top-chamber environments. Treatment 1 (T1, i.e., 60% shading with an enhanced ozone of 100±9 ppb), Treatment 2 (T2, i.e., 20% shading with an enhanced ozone of 100±9 ppb), and Control Check Treatment (CK, i.e., no shading with an enhanced ozone of 100±9 ppb), with two plots under each, were established to investigate the response of winter wheat under elevated ozone concentrations and varying solar irradiance. At the field level, linear temporal relationships between dry matter loss and cumulative stomatal ozone uptake were first established through a parameterized stomatal-flux model. At the regional level, ozone concentrations and meteorological variables, including solar irradiance, were simulated using the WRF-CMAQ model (i.e., a meteorology and air quality modeling system). These variables were then used to estimate cumulative stomatal ozone uptake for the four major winter wheat-growing provinces. The regional-level cumulative ozone uptake was then used as the independent variable in field data-based regression models to predict dry matter loss over space and time. Field-level results showed that over 85% (T1: R(2) = 0.85 & T2: R(2) = 0.89) of variation in dry matter loss was explained by cumulative ozone uptake. Dry matter was reduced by 3.8% in T1 and 2.2% in T2 for each mmol O3·m(-2) of cumulative ozone uptake. At the regional level, dry matter loss in winter wheat would reach 50% under elevated ozone concentrations and reduced solar irradiance as determined in T1, and 30% under conditions as determined in T2. Results from this study suggest that a combination of elevated ozone concentrations and reduced solar irradiance could result in substantial dry matter loss in the Chinese wheat-growing regions.

The Effect of Elevated Ozone Concentrations with Varying Shading on Dry Matter Loss in a Winter Wheat-Producing Region in China

PubMed Central

Xu, Jingxin; Zheng, Youfei; He, Yuhong; Wu, Rongjun; Mai, Boru; Kang, Hanqing

2016-01-01

Surface-level ozone pollution causes crop production loss by directly reducing healthy green leaf area available for carbon fixation. Ozone and its precursors also affect crop photosynthesis indirectly by decreasing solar irradiance. Pollutants are reported to have become even more severe in Eastern China over the last ten years. In this study, we investigated the effect of a combination of elevated ozone concentrations and reduced solar irradiance on a popular winter wheat Yangmai13 (Triticum aestivum L.) at field and regional levels in China. Winter wheat was grown in artificial shading and open-top-chamber environments. Treatment 1 (T1, i.e., 60% shading with an enhanced ozone of 100±9 ppb), Treatment 2 (T2, i.e., 20% shading with an enhanced ozone of 100±9 ppb), and Control Check Treatment (CK, i.e., no shading with an enhanced ozone of 100±9 ppb), with two plots under each, were established to investigate the response of winter wheat under elevated ozone concentrations and varying solar irradiance. At the field level, linear temporal relationships between dry matter loss and cumulative stomatal ozone uptake were first established through a parameterized stomatal-flux model. At the regional level, ozone concentrations and meteorological variables, including solar irradiance, were simulated using the WRF-CMAQ model (i.e., a meteorology and air quality modeling system). These variables were then used to estimate cumulative stomatal ozone uptake for the four major winter wheat-growing provinces. The regional-level cumulative ozone uptake was then used as the independent variable in field data-based regression models to predict dry matter loss over space and time. Field-level results showed that over 85% (T1: R2 = 0.85 & T2: R2 = 0.89) of variation in dry matter loss was explained by cumulative ozone uptake. Dry matter was reduced by 3.8% in T1 and 2.2% in T2 for each mmol O3·m-2 of cumulative ozone uptake. At the regional level, dry matter loss in winter wheat would reach 50% under elevated ozone concentrations and reduced solar irradiance as determined in T1, and 30% under conditions as determined in T2. Results from this study suggest that a combination of elevated ozone concentrations and reduced solar irradiance could result in substantial dry matter loss in the Chinese wheat-growing regions. PMID:26760509

Direct and Dry Deposited Single-Walled Carbon Nanotube Films Doped with MoO(x) as Electron-Blocking Transparent Electrodes for Flexible Organic Solar Cells.

PubMed

Jeon, Il; Cui, Kehang; Chiba, Takaaki; Anisimov, Anton; Nasibulin, Albert G; Kauppinen, Esko I; Maruyama, Shigeo; Matsuo, Yutaka

2015-07-01

Organic solar cells have been regarded as a promising electrical energy source. Transparent and conductive carbon nanotube film offers an alternative to commonly used ITO in photovoltaics with superior flexibility. This communication reports carbon nanotube-based indium-free organic solar cells and their flexible application. Direct and dry deposited carbon nanotube film doped with MoO(x) functions as an electron-blocking transparent electrode, and its performance is enhanced further by overcoating with PSS. The single-walled carbon nanotube organic solar cell in this work shows a power conversion efficiency of 6.04%. This value is 83% of the leading ITO-based device performance (7.48%). Flexible application shows 3.91% efficiency and is capable of withstanding a severe cyclic flex test.

HEATING ATTIC AIR USING SOLAR THERMAL ENERGY FOR SPACE HEATING AND DRYING APPLICATIONS

EPA Science Inventory

This unit is expected to replace the conventional forms of drying and will be able to supplement space heating. Replacement of these current forms of drying and space heating will result in the reduction of energy consumption from this sector which will also lead to cost savin...

The sun-protection factors of wet and dry T-shirts

NASA Astrophysics Data System (ADS)

Bartels, Richard; Loxsom, Fred

1998-02-01

The sunburn protection factors (SPF) of dry and wet samples of two white T-shirt materials were experimentally determined by measuring the spectral transmission of solar radiation through the materials. The dry and wet SPF's were, respectively: 15 and 5 for 100% cotton, and 19 and 17 for 35% cotton/65% polyester.

Antisoiling Coatings for Solar-Energy Devices

NASA Technical Reports Server (NTRS)

Cuddihy, E. F.; Willis, P.

1986-01-01

Fluorocarbons resist formation of adherent deposits. Promising coating materials reduce soiling of solar photovoltaic modules and possibly solar thermal collectors. Contaminating layers of various degrees of adherence form on surfaces of devices, partially blocking incident solar energy, reducing output power. Loose soil deposits during dry periods but washed off by rain. New coatings help prevent formation of more-adherent, chemically and physically bonded layers rain alone cannot wash away.

Analysis of Solar Chimneys in Different Climate Zones - Case of Social Housing in Ecuador

NASA Astrophysics Data System (ADS)

Godoy-Vaca, Luis; Almaguer, Manuel; Martínez-Gómez, Javier; Lobato, Andrea; Palme, Massimo

2017-10-01

The aim of this research is to simulate the performance of a solar chimney located in different macro-zones in Ecuador. The proposed solar chimney model was simulated using a python script in order to predict the temperature distribution and the mass flow over time. The results obtained were firstly compared with experimental data for dry-warm climate. Then, the model was evaluated and tested in real weather conditions: dry-warm, moist-warm and rainy-cold. In addition, the assumed chimney dimensions were chosen according to the literature for the studied conditions. In spite of evaluating the best nightly ventilation, different chimney wall materials were tested: solid brick, common brick and reinforced concrete. The results showed that concrete in a dry-warm climate, a metallic layer on the gap with solid brick in a moist-warm climate and reinforced concrete in a rainy cold climate used for the absorbent wall improve the thermal inertia of the social housing.

Publications | Concentrating Solar Power | NREL

Science.gov Websites

-including technical reports, journal articles, and conference papers-about its research and development (R Block and Balance of Plant R&D Supercritical CO2 Water Cooling Wet Dry Solar Field R&D Reflector Absorber Receivers Durability Solar field Thermal Energy Storage and Heat Transfer Fluids R&D Storage

Analysis of extreme summers and prior late winter/spring conditions in central Europe

NASA Astrophysics Data System (ADS)

Träger-Chatterjee, C.; Müller, R. W.; Bendix, J.

2013-05-01

Drought and heat waves during summer in mid-latitudes are a serious threat to human health and agriculture and have negative impacts on the infrastructure, such as problems in energy supply. The appearance of such extreme events is expected to increase with the progress of global warming. A better understanding of the development of extremely hot and dry summers and the identification of possible precursors could help improve existing seasonal forecasts in this regard, and could possibly lead to the development of early warning methods. The development of extremely hot and dry summer seasons in central Europe is attributed to a combined effect of the dominance of anticyclonic weather regimes and soil moisture-atmosphere interactions. The atmospheric circulation largely determines the amount of solar irradiation and the amount of precipitation in an area. These two variables are themselves major factors controlling the soil moisture. Thus, solar irradiation and precipitation are used as proxies to analyse extreme sunny and dry late winter/spring and summer seasons for the period 1958-2011 in Germany and adjacent areas. For this purpose, solar irradiation data from the European Center for Medium Range Weather Forecast 40-yr and interim re-analysis dataset, as well as remote sensing data are used. Precipitation data are taken from the Global Precipitation Climatology Project. To analyse the atmospheric circulation geopotential data at 850 hPa are also taken from the European Center for Medium Range Weather Forecast 40-yr and interim re-analysis datasets. For the years in which extreme summers in terms of high solar irradiation and low precipitation are identified, the previous late winter/spring conditions of solar irradiation and precipitation in Germany and adjacent areas are analysed. Results show that if the El Niño-Southern Oscillation (ENSO) is not very intensely developed, extremely high solar irradiation amounts, together with extremely low precipitation amounts during late winter/spring, might serve as precursor of extremely sunny and dry summer months to be expected.

Numerical and experimental investigation of direct solar crop dryer for farmers

NASA Astrophysics Data System (ADS)

Kareem, M. W.; Habib, Khairul; Sulaiman, S. A.

2015-07-01

This article presents a theoretical and experimental investigation on effects of weather on direct solar crop drying technique. The SIMULINK tool was employed to analyze the energy balance equations of the transient system model. A prototype of the drying system was made and data were collected between the months of June and July in Perak, Malaysia. The contribution of intense sunny days was encouraging despite the wet season, and the wind velocity was dynamic during the period of investigation. However, high percentage of relative humidity was observed. This constitutes a hindrance to efficient drying process. The reported studies were silent on the effect of thick atmospheric moisture content on drying rate of agricultural products in tropic climate. This finding has revealed the mean values of insolation, wind speed, moisturized air, system performance efficiency and chili microscopy image morphology. The predicted and measured results were compared with good agreement.

Recent advances in drying and dehydration of fruits and vegetables: a review.

PubMed

Sagar, V R; Suresh Kumar, P

2010-01-01

Fruits and vegetables are dried to enhance storage stability, minimize packaging requirement and reduce transport weight. Preservation of fruits and vegetables through drying based on sun and solar drying techniques which cause poor quality and product contamination. Energy consumption and quality of dried products are critical parameters in the selection of drying process. An optimum drying system for the preparation of quality dehydrated products is cost effective as it shortens the drying time and cause minimum damage to the product. To reduce the energy utilization and operational cost new dimensions came up in drying techniques. Among the technologies osmotic dehydration, vacuum drying, freeze drying, superheated steam drying, heat pump drying and spray drying have great scope for the production of quality dried products and powders.

Design and operation of a solarheated dry kiln for tropical latitudes

Treesearch

Brian Bond; Omar Espinoza; Philip Araman

2011-01-01

Lumber is usually dried to a specific moisture content prior to further manufacturing or use. While lumber can be air-dried, the ambient humidity in most localities prevents the lumber from reaching the moisture content necessary for dimensional stability and use, especially for interior use. Solar kilns are an inexpensive alternative to conventional steam-heated kilns...

Papaya drying and waste conversion system. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1982-02-12

This project, performed under United States Department of Energy Small-scale Appropriate Energy Technology Grant, involves demonstration of an integrated system using solar energy to process off-grade or reject fruit into marketable food products. The integrated system consists of three phases: (1) solar dehydration of usable fruit; (2) solar vacuum distillation of fermented wastes (peelings, rinds, skins, and seeds) to produce an ethanol fuel to use as a backup source of heat for dehydration; and (3) land reclamation by mixing stillage and compost with volcanic cinder and ash to produce on marginal land a rich soil suitable for growing more cropsmore » to dry. Although the system is not 100% complete the investigators have demonstrated that a small business can efficiently use solar energies in an integrated fashion to process waste into food, improve the quality of the land, and provide meaningful jobs in a region of very high unemployment.« less

Design and development of a solar array drive. [a direct drive solar array pointing mechanism

NASA Technical Reports Server (NTRS)

Rees, T.; Standing, J. M.

1977-01-01

The design and development of a dry lubricated direct drive solar array pointing mechanism is discussed for use on the Orbital Test Satellite (OTS), MAROTS, European Communication Satellite (ECS), and others. Results of life testing the original prototype and the OTS mechanism are presented together with an appraisal of expected future development.

Process of making solar cell module

DOEpatents

Packer, M.; Coyle, P.J.

1981-03-09

A process is presented for the manufacture of solar cell modules. A solution comprising a highly plasticized polyvinyl butyral is applied to a solar cell array. The coated array is dried and sandwiched between at last two sheets of polyvinyl butyral and at least two sheets of a rigid transparent member. The sandwich is laminated by the application of heat and pressure to cause fusion and bonding of the solar cell array with the rigid transparent members to produce a solar cell module.

Solar Collectors

NASA Technical Reports Server (NTRS)

1980-01-01

Solar Energy's solar panels are collectors for a solar energy system which provides heating for a drive-in bank in Akron, OH. Collectors were designed and manufactured by Solar Energy Products, a firm established by three former NASA employees. Company President, Frank Rom, an example of a personnel-type technology transfer, was a Research Director at Lewis Research Center, which conducts extensive solar heating and cooling research, including development and testing of high-efficiency flat-plate collectors. Rom acquired solar energy expertise which helped the company develop two types of collectors, one for use in domestic/commercial heating systems and the other for drying grain.

Optimization on drying conditions of a solar electrohydrodynamic drying system based on desirability concept

PubMed Central

Dalvand, Mohammad Jafar; Mohtasebi, Seyed Saeid; Rafiee, Shahin

2014-01-01

The purpose of this article was to present a new drying method for agricultural products. Electrohydrodynamic (EHD) has been applied for drying of agricultural materials due to several advantages such as energy saving, low cost equipment, low drying temperatures, and superior material quality. To evaluate this method, an EHD dryer based on solar (photovoltaic) energy was designed and fabricated. Moreover, the optimum condition for the EHD drying of kiwi fruit was studied by applying the Box–Behnken design of response surface methodology. The desirability function was applied for optimization in case of single objective and multiobjective functions. By using the multiobjective optimization method, maximum desirability value of 0.865 was obtained based on the following: applied voltage of 15 kV, field strength of 5.2 kV cm−1, without forced air stream, and finally a combination of 17 discharge electrodes (needles). The results indicated that increasing the applied voltage from 6 to 15 kV, moisture ratio (MR) decreased, though energy efficiency and energy consumption were increasing. On the other hand, field strength of 5.2 kV cm−1 was the optimal point in terms of MR. PMID:25493195

Optimization on drying conditions of a solar electrohydrodynamic drying system based on desirability concept.

PubMed

Dalvand, Mohammad Jafar; Mohtasebi, Seyed Saeid; Rafiee, Shahin

2014-11-01

The purpose of this article was to present a new drying method for agricultural products. Electrohydrodynamic (EHD) has been applied for drying of agricultural materials due to several advantages such as energy saving, low cost equipment, low drying temperatures, and superior material quality. To evaluate this method, an EHD dryer based on solar (photovoltaic) energy was designed and fabricated. Moreover, the optimum condition for the EHD drying of kiwi fruit was studied by applying the Box-Behnken design of response surface methodology. The desirability function was applied for optimization in case of single objective and multiobjective functions. By using the multiobjective optimization method, maximum desirability value of 0.865 was obtained based on the following: applied voltage of 15 kV, field strength of 5.2 kV cm(-1), without forced air stream, and finally a combination of 17 discharge electrodes (needles). The results indicated that increasing the applied voltage from 6 to 15 kV, moisture ratio (MR) decreased, though energy efficiency and energy consumption were increasing. On the other hand, field strength of 5.2 kV cm(-1) was the optimal point in terms of MR.

An Evaluation of Total Solar Reflectance and Spectral Band Ratioing Techniques for Estimating Soil Water Content

NASA Technical Reports Server (NTRS)

Reginato, R. J.; Vedder, J. F.; Idso, S. B.; Jackson, R. D.; Blanchard, M. B.; Goettelman, R.

1977-01-01

For several days in March of 1975, reflected solar radiation measurements were obtained from smooth and rough surfaces of wet, drying, and continually dry Avondale loam at Phoenix, Arizona, with pyranometers located 50 cm above the ground surface and a multispectral scanner flown at a 300-m height. The simple summation of the different band radiances measured by the multispectral scanner proved equally as good as the pyranometer data for estimating surface soil water content if the multispectral scanner data were standardized with respect to the intensity of incoming solar radiation or the reflected radiance from a reference surface, such as the continually dry soil. Without this means of standardization, multispectral scanner data are most useful in a spectral band ratioing context. Our results indicated that, for the bands used, no significant information on soil water content could be obtained by band ratioing. Thus the variability in soil water content should insignificantly affect soil-type discrimination based on identification of type-specific spectral signatures. Therefore remote sensing, conducted in the 0.4- to 1.0-micron wavelength region of the solar spectrum, would seem to be much More suited to identifying crop and soil types than to estimating of soil water content.

Thermal behavior modeling of a cabinet direct solar dryer as influenced by sensible heat storage in a fractured porous medium

NASA Astrophysics Data System (ADS)

Sandali, Messaoud; Boubekri, Abdelghani; Mennouche, Djamel

2018-05-01

Numerical simulation method has been employed to improve the thermal performance of cabinet direct solar dryer. The present study focused on the numerical simulation of a direct solar dryer with integration of a flat layer of fractured porous medium above the absorber plate in the aim to store thermal energy by sensible heat. Several calculations were conducted, using the finite volume method with a two-dimensional unsteady model implemented in the Fluent CFD software. The porous medium has been integrated with different thickness to show the influence of the medium thickness on the thermal performance of solar dryer. Different kinds of materials have been tested and studied. The effect of porosity of porous medium has been studied. The obtained results showed that the temperature of drying air is increased by 4°C with integration of porous medium. The increasing in the thickness of the porous medium by 1cm leads to increase the temperature of drying air by 2°C. The increasing of the medium porosity by 10% leads to decrease the temperature of drying air by 1°C. The best material is the one that has a highest specific heat and thermal conductivity.

Numerical characterisation of one-step and three-step solar air heating collectors used for cocoa bean solar drying.

PubMed

Orbegoso, Elder Mendoza; Saavedra, Rafael; Marcelo, Daniel; La Madrid, Raúl

2017-12-01

In the northern coastal and jungle areas of Peru, cocoa beans are dried using artisan methods, such as direct exposure to sunlight. This traditional process is time intensive, leading to a reduction in productivity and, therefore, delays in delivery times. The present study was intended to numerically characterise the thermal behaviour of three configurations of solar air heating collectors in order to determine which demonstrated the best thermal performance under several controlled operating conditions. For this purpose, a computational fluid dynamics model was developed to describe the simultaneous convective and radiative heat transfer phenomena under several operation conditions. The constructed computational fluid dynamics model was firstly validated through comparison with the data measurements of a one-step solar air heating collector. We then simulated two further three-step solar air heating collectors in order to identify which demonstrated the best thermal performance in terms of outlet air temperature and thermal efficiency. The numerical results show that under the same solar irradiation area of exposition and operating conditions, the three-step solar air heating collector with the collector plate mounted between the second and third channels was 67% more thermally efficient compared to the one-step solar air heating collector. This is because the air exposition with the surface of the collector plate for the three-step solar air heating collector former device was twice than the one-step solar air heating collector. Copyright © 2017 Elsevier Ltd. All rights reserved.

Hydrogen-Rich Syngas Production from Gasification and Pyrolysis of Solar Dried Sewage Sludge: Experimental and Modeling Investigations

PubMed Central

Ghrib, Amina; Friaa, Athar; Ouerghi, Aymen; Naoui, Slim; Belayouni, Habib

2017-01-01

Solar dried sewage sludge (SS) conversion by pyrolysis and gasification processes has been performed, separately, using two laboratory-scale reactors, a fixed-bed pyrolyzer and a downdraft gasifier, to produce mainly hydrogen-rich syngas. Prior to SS conversion, solar drying has been conducted in order to reduce moisture content (up to 10%). SS characterization reveals that these biosolids could be appropriate materials for gaseous products production. The released gases from SS pyrolysis and gasification present relatively high heating values (up to 9.96 MJ/kg for pyrolysis and 8.02  9.96 MJ/kg for gasification) due to their high contents of H2 (up to 11 and 7 wt%, resp.) and CH4 (up to 17 and 5 wt%, resp.). The yields of combustible gases (H2 and CH4) show further increase with pyrolysis. Stoichiometric models of both pyrolysis and gasification reactions were determined based on the global biomass formula, CαHβOγNδSε, in order to assist in the products yields optimization. PMID:28856162

Trap the Energy of the Sun. What We Make. Science and Technology Education in Philippine Society.

ERIC Educational Resources Information Center

Philippines Univ., Quezon City. Inst. for Science and Mathematics Education Development.

Filipino scientists and inventors have tried many ways of using solar energy. One simple device, made of wood and ordinary plastic sheets, traps solar energy to dry palay grains and other agricultural products. In this module, information and activities are provided to help students: (1) learn the advantages of using a solar crop dryer over direct…

Senegalese land surface change analysis and biophysical parameter estimation using NOAA AVHRR spectral data

NASA Technical Reports Server (NTRS)

Vukovich, Fred M.; Toll, David L.; Kennard, Ruth L.

1989-01-01

Surface biophysical estimates were derived from analysis of NOAA Advanced Very High Spectral Resolution (AVHRR) spectral data of the Senegalese area of west Africa. The parameters derived were of solar albedo, spectral visible and near-infrared band reflectance, spectral vegetative index, and ground temperature. Wet and dry linked AVHRR scenes from 1981 through 1985 in Senegal were analyzed for a semi-wet southerly site near Tambacounda and a predominantly dry northerly site near Podor. Related problems were studied to convert satellite derived radiance to biophysical estimates of the land surface. Problems studied were associated with sensor miscalibration, atmospheric and aerosol spatial variability, surface anisotropy of reflected radiation, narrow satellite band reflectance to broad solar band conversion, and ground emissivity correction. The middle-infrared reflectance was approximated with a visible AVHRR reflectance for improving solar albedo estimates. In addition, the spectral composition of solar irradiance (direct and diffuse radiation) between major spectral regions (i.e., ultraviolet, visible, near-infrared, and middle-infrared) was found to be insensitive to changes in the clear sky atmospheric optical depth in the narrow band to solar band conversion procedure. Solar albedo derived estimates for both sites were not found to change markedly with significant antecedent precipitation events or correspondingly from increases in green leaf vegetation density. The bright soil/substrate contributed to a high albedo for the dry related scenes, whereas the high internal leaf reflectance in green vegetation canopies in the near-infrared contributed to high solar albedo for the wet related scenes. The relationship between solar albedo and ground temperature was poor, indicating the solar albedo has little control of the ground temperature. The normalized difference vegetation index (NDVI) and the derived visible reflectance were more sensitive to antecedent rainfall amounts and green vegetation changes than were near-infrared changes. The information in the NDVI related to green leaf density changes primarily was from the visible reflectance. The contribution of the near-infrared reflectance to explaining green vegetation is largely reduced when there is a bright substrate.

Solar-powered hot-air system

NASA Technical Reports Server (NTRS)

1979-01-01

Solar-powered air heater supplies part or all of space heating requirements of residential or commercial buildings and is interfaced with air to water heat exchanger to heat domestic hot water. System has potential application in drying agricultural products such as cotton, lumber, corn, grains, and peanuts.

Radiation Dry Bias of the Vaisala RS92 Humidity Sensor

NASA Technical Reports Server (NTRS)

Vomel, H.; Selkirk, H.; Miloshevich, L.; Valverde-Canossa, J.; Valdes, J.; Kyro, E.; Kivi, R.; Stolz, W.; Peng, G.; Diaz, J. A.

2007-01-01

The comparison of simultaneous humidity measurements by the Vaisala RS92 radiosonde and by the Cryogenic Frostpoint Hygrometer (CFH) launched at Alajuela, Cosla Rica, during July 2005 reveals a large solar radiation dry bias of the Vaisala RS92 humidity sensor and a minor temperature-dependent calibration error. For soundings launched at solar zenith angles between 10" and 30 , the average dry bias is on the order of 9% at the surface and increases to 50% at 15 km. A simple pressure- and temperature-dependent correction based on the comparison with the CFH can reduce this error to less than 7% at all altitudes up to 15.2 km, which is 700 m below the tropical tropopause. The correction does not depend on relative humidity, but is able to reproduce the relative humidity distribution observed by the CFH.

Generation of daylight reference years for two European cities with different climate: Athens, Greece and Bratislava, Slovakia

NASA Astrophysics Data System (ADS)

Markou, M. T.; Kambezidis, H. D.; Bartzokas, A.; Darula, S.; Kittler, R.

2007-12-01

In this work, daylight reference years (DRYs), based on daylight and solar radiation measurements, are designed for two European cities, Athens, Greece and Bratislava, Slovakia, by using the Danish method, the Festa-Ratto technique and the Modified Sandia National Laboratories methodology. The data basis consists of 5-minute values of global and diffuse horizontal illuminance, global and diffuse horizontal irradiance, zenith luminance and solar altitude as well as of daily values of sunshine duration for 5 years for Athens and 8 years for Bratislava. Moreover, Linke's turbidity factor, luminous turbidity factor and relative sunshine duration are calculated and utilized. Then, for each DRY, the predominant sky-luminance distributions over Athens and Bratislava are identified, by using the methodology of Kittler et al., who corresponded the main sky conditions to 15 theoretical sky standards in diagrams of the ratio of zenith luminance to diffuse horizontal illuminance against solar altitude. For both cities the three aforementioned methods do not create identical DRYs. Despite the differences, the sky types defined for each of the two places seem not to depend on the choice of DRY. The predominant sky standard, for all of them, is a cloudless, polluted sky with a broad solar corona for Athens and an overcast sky with slight brightening towards the sun as well as very clear sky with low atmospheric turbidity for Bratislava. However, the selection of the DRY, which represents best the daylight conditions, is necessary for studies in saving energy in buildings. The DRY, which is created by the Modified Sandia National Laboratories method, is chosen for most cases, while the one created by the Danish method is also useful on certain occasions.

Improving Photovoltaic Energy Production with Fiber-Optic Distributed Temperature Sensing

NASA Astrophysics Data System (ADS)

Hausner, M. B.; Berli, M.

2014-12-01

The efficiency of solar photovoltaic (PV) generators declines sharply with increased temperatures. Peak solar exposure often occurs at the same time as peak temperatures, but solar PV installations are typically designed based on solar angle. In temperate areas, the peak temperatures may not be high enough to induce significant efficiency losses. In some of the areas with the greatest potential for solar development, however, summer air temperatures regularly reach 45 °C and PV panel temperatures exceed the air temperatures. Here we present a preliminary model of a PV array intended to optimize solar production in a hot and arid environment. The model begins with the diurnal and seasonal cycles in the angle and elevation of the sun, but also includes a meteorology-driven energy balance to project the temperatures of the PV panels and supporting structure. The model will be calibrated and parameterized using a solar array at the Desert Research Institute's (DRI) Renewable Energy Deployment and Display (REDD) facility in Reno, Nevada, and validated with a similar array at DRI's Las Vegas campus. Optical fibers will be installed on the PV panels and structural supports and interrogated by a distributed temperature sensor (DTS) to record the spatial and temporal variations in temperature. Combining the simulated panel temperatures, the efficiency-temperature relationship for the panels, and the known solar cycles at a site will allow us to optimize the design of future PV collectors (i.e., the aspect and angle of panels) for given production goals.

Solar-thermal fluid-wall reaction processing

DOEpatents

Weimer, Alan W.; Dahl, Jaimee K.; Lewandowski, Allan A.; Bingham, Carl; Buechler, Karen J.; Grothe, Willy

2006-04-25

The present invention provides a method for carrying out high temperature thermal dissociation reactions requiring rapid-heating and short residence times using solar energy. In particular, the present invention provides a method for carrying out high temperature thermal reactions such as dissociation of hydrocarbon containing gases and hydrogen sulfide to produce hydrogen and dry reforming of hydrocarbon containing gases with carbon dioxide. In the methods of the invention where hydrocarbon containing gases are dissociated, fine carbon black particles are also produced. The present invention also provides solar-thermal reactors and solar-thermal reactor systems.

Solar-Thermal Fluid-Wall Reaction Processing

DOEpatents

Weimer, A. W.; Dahl, J. K.; Lewandowski, A. A.; Bingham, C.; Raska Buechler, K. J.; Grothe, W.

2006-04-25

The present invention provides a method for carrying out high temperature thermal dissociation reactions requiring rapid-heating and short residence times using solar energy. In particular, the present invention provides a method for carrying out high temperature thermal reactions such as dissociation of hydrocarbon containing gases and hydrogen sulfide to produce hydrogen and dry reforming of hydrocarbon containing gases with carbon dioxide. In the methods of the invention where hydrocarbon containing gases are dissociated, fine carbon black particles are also produced. The present invention also provides solar-thermal reactors and solar-thermal reactor systems.

Progress of solar technology and potential farm uses

NASA Astrophysics Data System (ADS)

Heid, W. G., Jr.; Trotter, W. K.

1982-09-01

The efficient use of solar energy on farms for space heating and cooling of livestock buildings, drying crops, and heating farm homes is discussed. Low cost, homemade solar collectors, having multiple uses and a payback of less than 5 years, are the most popular systems. In contrast, most commercially produced systems are still too expensive for agricultural uses, partly because they fail to qualify for tax credits as large as those allowed for residential uses. The solar industry has shown little interest in marketing the low cost technologies specifically developed for agriculture.

Efficiency and design analysis of a solar thermal powered flat plate dryer (abstract)

USDA-ARS?s Scientific Manuscript database

Specialty crop fruit and vegetable pomaces are a common byproduct of the food processing and juicing industries. These pomaces can have high nutritional value, but are currently underutilized or treated as waste. Drum drying is one method that could be adopted to dry and stabilize fruit and vegetabl...

Effects of spring season solar drying process on sanitation indicators in sewage sludge and potential as a method for fertilizer production.

PubMed

Sypuła, Małgorzata; Paluszak, Zbigniew; Ligocka, Anna; Skowron, Krzysztof

2013-01-01

The agricultural use of sewage sludge is possible on condition of maintaining microbiological and parasitological standards, and one of the most modern methods improving its sanitary state is solar drying. In the presented study, the effect of this process on the elimination of indicator microorganisms (Escherichia coli, Salmonella Senftenberg W775, Enterococcus spp.) and eggs of Ascaris suum introduced into the biomass of sludge was examined. The experiment was carried out in the spring period with a maximal temperature of 18 °C inside the drying plant. Bacteria and parasite eggs were introduced into special carriers (cylinders filled with sewage sludge) and placed at selected points of the drier. The carriers were removed every 7 days and subject to a research procedure in order to estimate the number of bacteria and percentage of live eggs of Ascaris suum. Sanitization of the material was not obtained, since after 28 days of the process the final product contained a large concentration of Enterococcus spp. and S. Senftenberg W775 (10(5) -10(9) MPNg(-1)). Only the number of E. coli decreased by 6 log. During the process, the fastest decrease in the number of bacteria was observed in E. coli (ca 0.2 log/day), slower in enterococci (0.02-0.081 log/day), and the slowest in bacilli of the genus Salmonella (0.011-0.061 log/day). Sludge after drying also still contained 57-66% of live eggs of A. suum. The study proved that the solar drying of sludge in the spring period results in a product which poses a hazard for public and animal health and environmental sustainability, and should not be used as a fertilizer.

Off-farm applications of solar energy in agriculture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berry, R.E.

1980-01-01

Food processing applications make up almost all present off-farm studies of solar energy in agriculture. Research, development and demonstration projects on solar food processing have shown significant progress over the past 3 years. Projects have included computer simulation and mathematical models, hardware and process development for removing moisture from horticultural or animal products, integration of energy conservation with solar energy augmentation in conventional processes, and commercial scale demonstrations. The demonstration projects include solar heated air for drying prunes and raisins, soy beans and onions/garlic; and solar generated steam for orange juice pasteurization. Several new and planned projects hold considerable promisemore » for commerical exploitation in future food processes.« less

Variation in the Asian monsoon intensity and dry-wet condition since the Little Ice Age in central China revealed by an aragonite stalagmite

NASA Astrophysics Data System (ADS)

Yin, J.-J.; Yuan, D.-X.; Li, H.-C.; Cheng, H.; Li, T.-Y.; Edwards, R. L.; Lin, Y.-S.; Qin, J.-M.; Tang, W.; Zhao, Z.-Y.; Mii, H.-S.

2014-04-01

Highlight: this paper focuses on the climate variability in central China since 1300 AD, involving: 1. A well-dated, 1.5 year resolution stalagmite δ18O record from Lianhua Cave, central China; 2. Links of the δ18O record with regional dry-wet condition, monsoon intensity, and temperature over eastern China; 3. Correlations among drought events in the Lianhua record, solar irradiation, and ENSO index. We present a highly precisely 230Th/U dated, 1.5 year resolution δ18O record of an aragonite stalagmite (LHD1) collected from Lianhua Cave in Wuling mountain area of central China. The comparison of the δ18O record with the local instrumental record and historical documents exhibits at least 15 drought events in the Wuling mountain and adjacent areas during the Little Ice Age, in which some of them were corresponding to megadrought events in the broad Asian monsoonal region of China. Thus, the stalagmite δ18O record reveals variations in the summer monsoon precipitation and dry-wet condition in Wuling mountain area. The eastern China temperature varied with the solar activity, showing higher temperature under stronger solar irradiation which produces stronger summer monsoon. During Maunder, Dalton and 1900 sunspot minima, more severe drought events occurred, indicating weakening of the summer monsoon when solar activity decreased on decadal time scales. On interannual time scale, dry conditions in the studying area were prevailing under El Niño condition, which is also supported by the spectrum analysis. Hence, our record illustrates the linkage of Asian summer monsoon precipitation to solar irradiation and ENSO: wetter condition under stronger summer monsoon during warm periods and vice versa; During cold periods, the Walker circulation will shift toward central Pacific under El Niño condition, resulting further weakening of Asian summer monsoon. However, the δ18O of LHD1 record is positively correlated with temperature after ~1940 AD which is opposite to the δ18O - temperature relationship in earlier time. This anomaly relationship might be caused by the greenhouse-gas forcing.

Improved Food Drying and Storage Training Manual.

ERIC Educational Resources Information Center

Zweig, Peter R.; And Others

This manual is intended to serve as a guide for those who are helping future Peace Corps volunteers to acquire basic food drying and storage skills. Included in the guide are lesson outlines and handouts for use in each of the 30 sessions of the course. Representative topics discussed in the individual sessions are scheduling, solar dryers,…

Feasibility study analysis for multi-function dual energy oven (case study: tapioca crackers small medium enterprise)

NASA Astrophysics Data System (ADS)

Soraya, N. W.; El Hadi, R. M.; Chumaidiyah, E.; Tripiawan, W.

2017-12-01

Conventional drying process is constrained by weather (cloudy / rainy), and requires wide drying area, and provides low-quality product. Multi-function dual energy oven is the appropriate technology to solve these problems. The oven uses solar thermal or gas heat for drying various type of products, including tapioca crackers. Investment analysis in technical, operational, and financial aspects show that the multi-function dual energy oven is feasible to be implemented for small medium enterprise (SME) processing tapioca crackers.

Automated Array Assembly Task In-depth Study of Silicon Wafer Surface Texturizing

NASA Technical Reports Server (NTRS)

Jones, G. T.; Chitre, S.; Rhee, S. S.; Allison, K. L.

1979-01-01

A low cost wafer surface texturizing process was studied. An investigation of low cost cleaning operations to clean residual wax and organics from the surface of silicon wafers was made. The feasibility of replacing dry nitrogen with clean dry air for drying silicon wafers was examined. The two stage texturizing process was studied for the purpose of characterizing relevant parameters in large volume applications. The effect of gettering solar cells on photovoltaic energy conversion efficiency is described.

The impact of the gulf war on the Arabian environment—I. Particulate pollution and reduction of solar irradiance

NASA Astrophysics Data System (ADS)

El-Shobokshy, Mohammad S.; Al-Saedi, Yaseen G.

This paper investigates some of the air pollution problems which have been created as a result of the Gulf war in early 1991. Temporary periods of increased dust storm activity have been observed in Saudi Arabia. This is presumably due to disturbance of the desert surface by the extremely large number of tanks and other war machines before and during the war. The concentrations of inhalable dust particles (<15 μm) increased during the months just after the war by a factor of about 1.5 of their values during the same months of the previous year, 1990. The total horizontal solar energy flux in Riyadh has been significantly reduced during dry days with no clouds. This is attributed to the presence of soot particles, which have been generated at an extremely high rate from the fired oil fields in Kuwait. The direct normal solar insolation were also measured at the photovoltaic solar power plant in Riyadh during these days and significant reductions were observed due to the effective absorption of solar radiation by soot particles. The generated power from the plant has been reduced during days with a polluted atmosphere by about 50-80% of the expected value for such days, if the atmosphere were dry and clear.

Preserving Food by Drying. A Math/Science Teaching Manual. Appropriate Technologies for Development. Manual No. M-10.

ERIC Educational Resources Information Center

Fahy, Cynthia; And Others

This manual presents a design for teaching science principles and mathematics concepts through a sequence of activities concentrating on weather, solar food dryers, and nutrition. Part I focuses on the effect of solar energy on air and water, examining the concepts of evaporation, condensation, radiation, conduction, and convection. These concepts…

Use of Solar Energy Hybrid Dryer with Techno-Ergonomic Application to Increase Productivity of Dodol Wokers in Buleleng, Bali

NASA Astrophysics Data System (ADS)

Santosa, I. G.; Sutarna, I. N.

2018-01-01

Penglatan Village is one of dodol industrial centres in Buleleng Regency, Bali. Dodol is a balinese traditional snack that usually used for religion ceremonies offering or “sesajen”. Dodol’s making processes had several layer of stages, from making dough, stirring dough, packaging and drying dodol. Because the drying process is done with traditional work tools, this process cause several ergonomic problems. Based on preliminary research, the complaints that felt by dodol workers are pain in the neck, shoulders, back, waist, head, and hands. Therefore, productivity of workers are decreasing. This problem solved by designing a hybrid solar drying tools with the application of techno-ergonomic, appropriate technology concept (TTG) and from ergonomic science with the application of SHIP concept (systemic, holistic, interdisciplinary, participatory). This research use 20 people as sample. The sample performance is observed while working traditionally and using techno-ergonomic hybrid solar dryer tools. The measurements conducted three times which are First Period (PI), Second Period (PII), and Third Period (PIII) with interspersed time for rest. WOP (washing out period) is intended to eliminate residual effects. The data were analyzed with SPSS program with significance level of 0.05. Hopefully, with this solution will improve worker productivity.

Developments and trends in fruit bar production and characterization.

PubMed

Orrego, C E; Salgado, N; Botero, C A

2014-01-01

Fruits serve as a source of energy, vitamins, minerals, and dietary fiber. One of the barriers in increasing fruit and vegetables consumption is time required to prepare them. Overall, fruit bars have a far greater nutritional value than the fresh fruits because all nutrients are concentrated and, therefore, would be a convenience food assortment to benefit from the health benefits of fruits. The consumers prefer fruit bars that are more tasted followed by proper textural features that could be obtained by establishing the equilibrium of ingredients, the proper choosing of manufacturing stages and the control of the product final moisture content. Fruit bar preparations may include a mixture of pulps, fresh or dried fruit, sugar, binders, and a variety of minor ingredients. Additionally to the conventional steps of manufacturing (pulping, homogenizing, heating, concentrating, and drying) there have been proposed the use of gelled fruit matrices, dried gels or sponges, and extruders as new trends for processing fruit bars. Different single-type dehydration or combined methods include, in order of increasing process time, air-infrared, vacuum and vacuum-microwave drying convective-solar drying, convective drying, and freeze drying are also suggested as alternative to solar traditional drying stage. The dehydration methods that use vacuum exhibited not only higher retention of antioxidants but also better color, texture, and rehydration capacity. Antioxidant activity resulting from the presence of phenolic compounds in the bars is well established. Besides this, fruit bars are also important sources of carbohydrates and minerals. Given the wide range of bioactive factors in fresh fruits that are preserved in fruit bars, it is plausible that their uptake consumption have a positive effect in reducing the risk of many diseases.

Imprint of long-term solar signal in groundwater recharge fluctuation rates from Northwest China

NASA Astrophysics Data System (ADS)

Tiwari, R. K.; Rajesh, Rekapalli

2014-05-01

Multiple spectral and statistical analyses of a 700 yearlong temporal record of groundwater recharge from the dry lands, Badain Jaran Desert (Inner Mongolia) of Northwest China reveal a stationary harmonic cycle at ~200 ± 20 year. Interestingly, the underlying periodicity in groundwater recharge fluctuations is similar to those of solar-induced climate cycle "Suess wiggles" and appears to be coherent with phases of the climate fluctuations and solar cycles. Matching periodicity of groundwater recharge rates and solar and climate cycles renders a strong impression that solar-induced climate signals may act as a critical amplifier for driving the underlying hydrographic cycle through the common coupling of long-term Sun-climate groundwater linkages.

Tropical field performance of dual-pass PV tray dryer

NASA Astrophysics Data System (ADS)

Iskandar, A. Noor; Ya'acob, M. E.; Anuar, M. S.

2017-09-01

Solar Photovoltaic technology has become the preferable solution in many countries around the globe to solve the ever increasing energy demand of the consumers. In line with the consumer need, food processing technology has huge potentials of integration with the renewable energy resources especially in drying process which consumes the highest electricity loads. Traditionally, the solar dryer technology was applied in agriculture and food industries utilizing the sun's energy for drying process, but this is highly dependable on the weather condition and surrounding factors. This work shares some field performance of the new design of portable dual-pass PV tray dryer for drying crops in an enclosed system. The dual-pass PV tray dryer encompass a lightweight aluminium box structure with dimensions of 1.1m (L) x 0.6m (W) x 0.2m (H) and can hold a load capacity of 300g - 3kg of crop depending on the types of the crops. Experiments of field performance monitoring were conducted in October -November 2016 which justifies a considerable reduction in time and crops quality improvement when using the dual-pass PV tray dryer as compared to direct-sun drying.

Environmental dust effects on aluminum surfaces in humid air ambient.

PubMed

Yilbas, Bekir Sami; Hassan, Ghassan; Ali, Haider; Al-Aqeeli, Nasser

2017-04-05

Environmental dusts settle on surfaces and influence the performance of concentrated solar energy harvesting devices, such as aluminum troughs. The characteristics of environmental dust and the effects of mud formed from the dust particles as a result of water condensing in humid air conditions on an aluminum wafer surface are examined. The dissolution of alkaline and alkaline earth compounds in water condensate form a chemically active mud liquid with pH 8.2. Due to gravity, the mud liquid settles at the interface of the mud and the aluminum surface while forming locally scattered patches of liquid films. Once the mud liquid dries, adhesion work to remove the dry mud increases significantly. The mud liquid gives rise to the formation of pinholes and local pit sites on the aluminum surface. Morphological changes due to pit sites and residues of the dry mud on the aluminum surface lower the surface reflection after the removal of the dry mud from the surface. The characteristics of the aluminum surface can address the dust/mud-related limitations of reflective surfaces and may have implications for the reductions in the efficiencies of solar concentrated power systems.

Environmental dust effects on aluminum surfaces in humid air ambient

PubMed Central

Yilbas, Bekir Sami; Hassan, Ghassan; Ali, Haider; Al-Aqeeli, Nasser

2017-01-01

Environmental dusts settle on surfaces and influence the performance of concentrated solar energy harvesting devices, such as aluminum troughs. The characteristics of environmental dust and the effects of mud formed from the dust particles as a result of water condensing in humid air conditions on an aluminum wafer surface are examined. The dissolution of alkaline and alkaline earth compounds in water condensate form a chemically active mud liquid with pH 8.2. Due to gravity, the mud liquid settles at the interface of the mud and the aluminum surface while forming locally scattered patches of liquid films. Once the mud liquid dries, adhesion work to remove the dry mud increases significantly. The mud liquid gives rise to the formation of pinholes and local pit sites on the aluminum surface. Morphological changes due to pit sites and residues of the dry mud on the aluminum surface lower the surface reflection after the removal of the dry mud from the surface. The characteristics of the aluminum surface can address the dust/mud-related limitations of reflective surfaces and may have implications for the reductions in the efficiencies of solar concentrated power systems. PMID:28378798

Control of PbI2 nucleation and crystallization: towards efficient perovskite solar cells based on vapor-assisted solution process

NASA Astrophysics Data System (ADS)

Yang, Chongqiu; Peng, Yanke; Simon, Terrence; Cui, Tianhong

2018-04-01

Perovskite solar cells (PSC) have outstanding potential to be low-cost, high-efficiency photovoltaic devices. The PSC can be fabricated by numerous techniques; however, the power conversion efficiency (PCE) for the two-step-processed PSC falls behind that of the one-step method. In this work, we investigate the effects of relative humidity (RH) and dry air flow on the lead iodide (PbI2) solution deposition process. We conclude that the quality of the PbI2 film is critical to the development of the perovskite film and the performance of the PSC device. Low RH and dry air flow used during the PbI2 spin coating procedure can increase supersaturation concentration to form denser PbI2 nuclei and a more suitable PbI2 film. Moreover, airflow-assisted PbI2 drying and thermal annealing steps can smooth transformation from the nucleation stage to the crystallization stage.

Pathfinder aircraft flight #1

NASA Image and Video Library

1996-11-19

The Pathfinder research aircraft's solar cell arrays are prominently displayed as it touches down on the bed of Rogers Dry Lake at the Dryden Flight Research Center, Edwards, California, following a test flight. The solar arrays covered more than 75 percent of Pathfinder's upper wing surface, and provided electricity to power its six electric motors, flight controls, communications links and a host of scientific sensors.

Effect of vanadium carbide on dry sliding wear behavior of powder metallurgy AISI M2 high speed steel processed by concentrated solar energy

DOE Office of Scientific and Technical Information (OSTI.GOV)

García, C.

Mixtures of AISI M2 high speed steel and vanadium carbide (3, 6 or 10 wt.%) were prepared by powder metallurgy and sintered by concentrated solar energy (CSE). Two different powerful solar furnaces were employed to sinter the parts and the results were compared with those obtained by conventional powder metallurgy using a tubular electric furnace. CSE allowed significant reduction of processing times and high heating rates. The wear resistance of compacts was studied by using rotating pin-on-disk and linearly reciprocating ball-on-flat methods. Wear mechanisms were investigated by means of scanning electron microscopy (SEM) observations and chemical inspections of the microstructuresmore » of the samples. Better wear properties than those obtained by conventional powder metallurgy were achieved. The refinement of the microstructure and the formation of carbonitrides were the reasons for this. - Highlights: •Powder metallurgy of mixtures of M2 high speed steel and VC are studied. •Some sintering is done by concentrated solar energy. •Rotating pin-on-disk and linearly reciprocating ball-on-flat methods are used. •The tribological properties and wear mechanisms, under dry sliding, are studied.« less

Income generation for women with renewable energy technologies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stone, L.

1996-10-01

70% of the world`s poor are women. The poverty that is especially hard hitting for rural women throughout the world has many causes. The lack of access to education, credit and new technologies make it almost impossible for women to earn an income. Yet, when women earn an income, it not only improves their lives, but also improves the lives of their children and their communities. Solar energy technologies, along with access to credit, can help rural women improve the quality of their lives through income generating enterprises. The technologies discussed are solar cooking, solar food drying, solar blenders, andmore » photovoltaics.« less

Blanching, salting and sun drying of different pumpkin fruit slices.

PubMed

Workneh, T S; Zinash, A; Woldetsadik, K

2014-11-01

The study was aimed at assessing the quality of pumpkin (Cucuribita Spp.) slices that were subjected to pre-drying treatments and drying using two drying methods (uncontrolled sun and oven) fruit accessions. Pre-drying had significant (P ≤ 0.05) effect on the quality of dried pumpkin slices. 10 % salt solution dipped pumpkin fruit slices had good chemical quality. The two-way interaction between drying methods and pre-drying treatments had significant (P ≤ 0.05) effect on chemical qualities. Pumpkin subjected to salt solution dipping treatment and oven dried had higher chemical concentrations. Among the pumpkin fruit accessions, pumpkin accession 8007 had the superior TSS, total sugar and sugar to acid ratio after drying. Among the three pre-drying treatment, salt solution dipping treatment had significant (P ≤ 0.05) effect and the most efficient pre-drying treatment to retain the quality of dried pumpkin fruits without significant chemical quality deterioration. Salt dipping treatment combined with low temperature (60 °C) oven air circulation drying is recommended to maintain quality of dried pumpkin slices. However, since direct sun drying needs extended drying time due to fluctuation in temperature, it is recommended to develop or select best successful solar dryer for use in combination with pre-drying salt dipping or blanching treatments.

Experimental evaluation of drying characteristics of sewage sludge and hazelnut shell mixtures

NASA Astrophysics Data System (ADS)

Pehlivan, Hüseyin; Ateş, Asude; Özdemir, Mustafa

2016-11-01

In this study the drying behavior of organic and agricultural waste mixtures has been experimentally investigated. The usability of sewage sludge as an organic waste and hazelnut shell as an agricultural waste was assessed in different mixture range. The paper discusses the applicability of these mixtures as a recovery energy source. Moisture content of mixtures has been calculated in laboratory and plant conditions. Indoor and outdoor solar sludge drying plants were constructed in pilot scale for experimental purposes. Dry solids and climatic conditions were constantly measured. A total more than 140 samples including for drying has been carried out to build up results. Indoor and outdoor weather conditions are taken into consideration in winter and summer. The most effective drying capacity is obtained in mixture of 20 % hazelnut shell and 80 % sewage sludge.

Solution-processed copper-nickel nanowire anodes for organic solar cells

NASA Astrophysics Data System (ADS)

Stewart, Ian E.; Rathmell, Aaron R.; Yan, Liang; Ye, Shengrong; Flowers, Patrick F.; You, Wei; Wiley, Benjamin J.

2014-05-01

This work describes a process to make anodes for organic solar cells from copper-nickel nanowires with solution-phase processing. Copper nanowire films were coated from solution onto glass and made conductive by dipping them in acetic acid. Acetic acid removes the passivating oxide from the surface of copper nanowires, thereby reducing the contact resistance between nanowires to nearly the same extent as hydrogen annealing. Films of copper nanowires were made as oxidation resistant as silver nanowires under dry and humid conditions by dipping them in an electroless nickel plating solution. Organic solar cells utilizing these completely solution-processed copper-nickel nanowire films exhibited efficiencies of 4.9%.This work describes a process to make anodes for organic solar cells from copper-nickel nanowires with solution-phase processing. Copper nanowire films were coated from solution onto glass and made conductive by dipping them in acetic acid. Acetic acid removes the passivating oxide from the surface of copper nanowires, thereby reducing the contact resistance between nanowires to nearly the same extent as hydrogen annealing. Films of copper nanowires were made as oxidation resistant as silver nanowires under dry and humid conditions by dipping them in an electroless nickel plating solution. Organic solar cells utilizing these completely solution-processed copper-nickel nanowire films exhibited efficiencies of 4.9%. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr01024h

Elastic MCF Rubber with Photovoltaics and Sensing for Use as Artificial or Hybrid Skin (H-Skin): 1st Report on Dry-Type Solar Cell Rubber with Piezoelectricity for Compressive Sensing.

PubMed

Shimada, Kunio

2018-06-05

Ordinary solar cells are very difficult to bend, squash by compression, or extend by tensile strength. However, if they were to possess elastic, flexible, and extensible properties, in addition to piezo-electricity and resistivity, they could be put to effective use as artificial skin installed over human-like robots or humanoids. Further, it could serve as a husk that generates electric power from solar energy and perceives any force or temperature changes. Therefore, we propose a new type of artificial skin, called hybrid skin (H-Skin), for a humanoid robot having hybrid functions. In this study, a novel elastic solar cell is developed from natural rubber that is electrolytically polymerized with a configuration of magnetic clusters of metal particles incorporated into the rubber, by applying a magnetic field. The material thus produced is named magnetic compound fluid rubber (MCF rubber) that is elastic, flexible, and extensible. The present report deals with a dry-type MCF rubber solar cell that uses photosensitized dye molecules. First, the photovoltaic mechanism in the material is investigated. Next, the changes in the photovoltaic properties of its molecules due to irradiation by visible light are measured under compression. The effect of the compression on its piezoelectric properties is investigated.

Variation in the Asian monsoon intensity and dry-wet conditions since the Little Ice Age in central China revealed by an aragonite stalagmite

NASA Astrophysics Data System (ADS)

Yin, J.-J.; Yuan, D.-X.; Li, H.-C.; Cheng, H.; Li, T.-Y.; Edwards, R. L.; Lin, Y.-S.; Qin, J.-M.; Tang, W.; Zhao, Z.-Y.; Mii, H.-S.

2014-10-01

This paper focuses on the climate variability in central China since AD 1300, involving: (1) a well-dated, 1.5-year resolution stalagmite δ18O record from Lianhua Cave, central China (2) links of the δ18O record with regional dry-wet conditions, monsoon intensity, and temperature over eastern China (3) correlations among drought events in the Lianhua record, solar irradiation, and ENSO (El Niño-Southern Oscillation) variation. We present a highly precise, 230Th / U-dated, 1.5-year resolution δ18O record of an aragonite stalagmite (LHD1) collected from Lianhua Cave in the Wuling Mountain area of central China. The comparison of the δ18O record with the local instrumental record and historical documents indicates that (1) the stalagmite δ18O record reveals variations in the summer monsoon intensity and dry-wet conditions in the Wuling Mountain area. (2) A stronger East Asian summer monsoon (EASM) enhances the tropical monsoon trough controlled by ITCZ (Intertropical Convergence Zone), which produces higher spring quarter rainfall and isotopically light monsoonal moisture in the central China. (3) The summer quarter/spring quarter rainfall ratio in central China can be a potential indicator of the EASM strength: a lower ratio corresponds to stronger EASM and higher spring rainfall. The ratio changed from <1 to >1 after 1950, reflecting that the summer quarter rainfall of the study area became dominant under stronger influence of the Northwestern Pacific High. Eastern China temperatures varied with the solar activity, showing higher temperatures under stronger solar irradiation, which produced stronger summer monsoons. During Maunder, Dalton and 1900 sunspot minima, more severe drought events occurred, indicating a weakening of the summer monsoon when solar activity decreased on decadal timescales. On an interannual timescale, dry conditions in the study area prevailed under El Niño conditions, which is also supported by the spectrum analysis. Hence, our record illustrates the linkage of Asian summer monsoon precipitation to solar irradiation and ENSO: wetter conditions in the study area under stronger summer monsoon during warm periods, and vice versa. During cold periods, the Walker Circulation will shift toward the central Pacific under El Niño conditions, resulting in a further weakening of Asian summer monsoons.

30-kW SEP Spacecraft as Secondary Payloads for Low-Cost Deep Space Science Missions

NASA Technical Reports Server (NTRS)

Brophy, John R.; Larson, Tim

2013-01-01

The Solar Array System contracts awarded by NASA's Space Technology Mission Directorate are developing solar arrays in the 30 kW to 50 kW power range (beginning of life at 1 AU) that have significantly higher specific powers (W/kg) and much smaller stowed volumes than conventional rigid-panel arrays. The successful development of these solar array technologies has the potential to enable new types of solar electric propulsion (SEP) vehicles and missions. This paper describes a 30-kW electric propulsion vehicle built into an EELV Secondary Payload Adapter (ESPA) ring. The system uses an ESPA ring as the primary structure and packages two 15-kW Megaflex solar array wings, two 14-kW Hall thrusters, a hydrazine Reaction Control Subsystem (RCS), 220 kg of xenon, 26 kg of hydrazine, and an avionics module that contains all of the rest of the spacecraft bus functions and the instrument suite. Direct-drive is used to maximize the propulsion subsystem efficiency and minimize the resulting waste heat and required radiator area. This is critical for packaging a high-power spacecraft into a very small volume. The fully-margined system dry mass would be approximately 1120 kg. This is not a small dry mass for a Discovery-class spacecraft, for example, the Dawn spacecraft dry mass was only about 750 kg. But the Dawn electric propulsion subsystem could process a maximum input power of 2.5 kW, and this spacecraft would process 28 kW, an increase of more than a factor of ten. With direct-drive the specific impulse would be limited to about 2,000 s assuming a nominal solar array output voltage of 300 V. The resulting spacecraft would have a beginning of life acceleration that is more than an order of magnitude greater than the Dawn spacecraft. Since the spacecraft would be built into an ESPA ring it could be launched as a secondary payload to a geosynchronous transfer orbit significantly reducing the launch costs for a planetary spacecraft. The SEP system would perform the escape from Earth and then the heliocentric transfer to the science target.

Fruit Leathers: Method of Preparation and Effect of Different Conditions on Qualities

PubMed Central

Diamante, Lemuel M.; Bai, Xue; Busch, Janette

2014-01-01

Fruit leathers are dehydrated fruit products which are eaten as snacks or desserts. They are flexible sheets that have a concentrated fruit flavor and nutritional aspects. Most fruit leathers are prepared by mixing fruit puree and other additives like sugar, pectin, acid, glucose syrup, color, and potassium metabisulphite and then dehydrating them under specific conditions. Various drying systems including combined convective and far-infrared drying, hot air drying, microwave drying, solar drying, and sun drying have been used to make fruit leathers. Most fruit leathers are dried at 30 to 80°C for up to 24 hours until the target final moisture content (12–20%) has been reached. Research about fruit leathers began in the 1970s. This work has reviewed published papers on fruit leathers in order to summarize useful information about fruit leathers on methods of preparation, effects of drying condition, and effects of packaging and storage, which will be useful to many in the food industry and consumers who are health-conscious. PMID:26904618

Effect of different drying techniques on bioactive components, fatty acid composition, and volatile profile of robusta coffee beans.

PubMed

Dong, Wenjiang; Hu, Rongsuo; Chu, Zhong; Zhao, Jianping; Tan, Lehe

2017-11-01

This study investigated the effect of different drying techniques, namely, room-temperature drying (RTD), solar drying (SD), heat-pump drying (HPD), hot-air drying (HAD), and freeze drying (FD), on bioactive components, fatty acid composition, and the volatile compound profile of robusta coffee beans. The data showed that FD was an effective method to preserve fat, organic acids, and monounsaturated fatty acids. In contrast, HAD was ideal for retaining polyunsaturated fatty acids and amino acids. Sixty-two volatile compounds were identified in the differently dried coffee beans, representing 90% of the volatile compounds. HPD of the coffee beans produced the largest number of volatiles, whereas FD resulted in the highest volatile content. A principal component analysis demonstrated a close relationship between the HPD, SD, and RTD methods whereas the FD and HAD methods were significantly different. Overall, the results provide a basis for potential application to other similar thermal sensitive materials. Copyright © 2017 Elsevier Ltd. All rights reserved.

Subsurface Salts in Antarctic Dry Valley Soils

NASA Technical Reports Server (NTRS)

Englert, P.; Bishop, J. L.; Gibson, E. K.; Koeberl, C.

2013-01-01

The distribution of water-soluble ions, major and minor elements, and other parameters were examined to determine the extent and effects of chemical weathering on cold desert soils. Patterns at the study sites support theories of multiple salt forming processes, including marine aerosols and chemical weathering of mafic minerals. Periodic solar-mediated ionization of atmospheric nitrogen might also produce high nitrate concentrations found in older sediments. Chemical weathering, however, was the major contributor of salts in Antarctic Dry Valleys. The Antarctic Dry Valleys represent a unique analog for Mars, as they are extremely cold and dry desert environments. Similarities in the climate, surface geology, and chemical properties of the Dry Valleys to that of Mars imply the possible presence of these soil formation mechanisms on Mars, other planets and icy satellites.

A novel technique for the production of cool colored concrete tile and asphalt shingle roofing products

DOE Office of Scientific and Technical Information (OSTI.GOV)

Levinson, Ronnen; Akbari, Hashem; Berdahl, Paul

The widespread use of solar-reflective roofing materials can save energy, mitigate urban heat islands and slow global warming by cooling the roughly 20% of the urban surface that is roofed. In this study we created prototype solar-reflective nonwhite concrete tile and asphalt shingle roofing materials using a two-layer spray coating process intended to maximize both solar reflectance and factory-line throughput. Each layer is a thin, quick-drying, pigmented latex paint based on either acrylic or a poly(vinylidene fluoride)/acrylic blend. The first layer is a titanium dioxide rutile white basecoat that increases the solar reflectance of a gray-cement concrete tile from 0.18more » to 0.79, and that of a shingle surfaced with bare granules from 0.06 to 0.62. The second layer is a 'cool' color topcoat with weak near-infrared (NIR) absorption and/or strong NIR backscattering. Each layer dries within seconds, potentially allowing a factory line to pass first under the white spray, then under the color spray. We combined a white basecoat with monocolor topcoats in various shades of red, brown, green and blue to prepare 24 cool color prototype tiles and 24 cool color prototypes shingles. The solar reflectances of the tiles ranged from 0.26 (dark brown; CIELAB lightness value L* = 29) to 0.57 (light green; L* = 76); those of the shingles ranged from 0.18 (dark brown; L* = 26) to 0.34 (light green; L* = 68). Over half of the tiles had a solar reflectance of at least 0.40, and over half of the shingles had a solar reflectance of at least 0.25.« less

Modeling of electrohydrodynamic drying process using response surface methodology

PubMed Central

Dalvand, Mohammad Jafar; Mohtasebi, Seyed Saeid; Rafiee, Shahin

2014-01-01

Energy consumption index is one of the most important criteria for judging about new, and emerging drying technologies. One of such novel and promising alternative of drying process is called electrohydrodynamic (EHD) drying. In this work, a solar energy was used to maintain required energy of EHD drying process. Moreover, response surface methodology (RSM) was used to build a predictive model in order to investigate the combined effects of independent variables such as applied voltage, field strength, number of discharge electrode (needle), and air velocity on moisture ratio, energy efficiency, and energy consumption as responses of EHD drying process. Three-levels and four-factor Box–Behnken design was employed to evaluate the effects of independent variables on system responses. A stepwise approach was followed to build up a model that can map the entire response surface. The interior relationships between parameters were well defined by RSM. PMID:24936289

The magnificent African eclipse

NASA Astrophysics Data System (ADS)

McGee, H. W.; James, N. D.

2001-08-01

The first total solar eclipse of the new millennium swept across central Africa on 2001 June 21, darkening the sky in a track which took in Angola, Zambia, Zimbabwe, Mozambique and Madagascar. Thousands of visitors from Europe, many of whom were disappointed at home in 1999, converged on the continent to view the event and were rewarded with a magnificent solar-maximum corona, seen for the most part in perfectly clear, dry transparent skies.

Use of solar distillation for olive mill wastewater drying and recovery of polyphenolic compounds.

PubMed

Sklavos, Sotirios; Gatidou, Georgia; Stasinakis, Athanasios S; Haralambopoulos, Dias

2015-10-01

Olive mill wastewater (OMW) is characterized by its high organic load and the presence of phenolic compounds. For first time, a solar distillator was used to investigate the simultaneous solar drying of OMW and the recovery of phenolic compounds with antioxidant properties in the distillate. Two experiments were conducted and the role of thermal insulation on the performance of the distiller was studied. The use of insulation resulted to higher temperatures in the distillator (up to 84.3 °C and 78.5 °C at the air and sludge, respectively), shorter period for OMW dewatering (14 days), while it increased the performance of distillator by 26.1%. Chemical characterization of the distillate showed that pH and COD concentration gradually decreased during the experiments, whereas an opposite trend was noticed for conductivity and total phenols concentration. Almost 4% of the total phenols found initially in OMW were transferred to the distillate when an insulated solar distillator was used. Gas chromatographic analysis of collected distillates confirmed the presence of tyrosol in all samples; whereas hydroxytyrosol was found only in fresh collected distillate samples. Further experiments should be conducted to optimize the process and quantify the concentrations of recovered phenolic compounds. Copyright © 2015 Elsevier Ltd. All rights reserved.

Improving the Sun Drying of Apricots (Prunus armeniaca) with Photo-Selective Dryer Cabinet Materials.

PubMed

Milczarek, Rebecca R; Avena-Mascareno, Roberto; Alonzo, Jérôme; Fichot, Mélissa I

2016-10-01

Photo-selective materials have been studied for their effects on the preharvest quality of horticultural crops, but little work has been done on potential postharvest processing effects. The aim of this work was to characterize the effects of 5 different photo-selective acrylic materials (used as the lid to a single-layer sun drying cabinet) on the drying rate and quality of apricots (Prunus armeniaca). Photo-selective cabinet materials that transmit light in the visible portion of the solar spectrum accelerate the apricots' drying rate in both the early period of drying and the course of drying as a whole. These materials do not significantly affect the measured quality metrics during the first day of sun drying. However, when drying is taken to completion, some minor but significant quality differences are observed. Infrared-blocking material produces dried apricot with lower red color, compared to clear, opaque black, and ultraviolet-blocking materials. Clear material produced dried apricot with significantly lower antioxidant activity, compared to black and infrared-blocking materials. Using appropriate photo-selective drying cabinet materials can reduce the required sun drying time for apricots by 1 to 2 d, compared with fully shaded drying. Ultraviolet-blocking material is recommended to maximize drying rate and minimize quality degradation. © 2016 Institute of Food Technologists®.

Air solar collectors in building use - A review

NASA Astrophysics Data System (ADS)

Bejan, Andrei-Stelian; Labihi, Abdelouhab; Croitoru, Cristiana; Catalina, Tiberiu

2018-02-01

In the current energy and environmental context it is imperative to implement systems based on renewable energy sources in order to reduce energy consumptions worldwide. Solar collectors are studied by many years and many researchers are focusing their attention in order to increase their efficiency and cost-effectiveness. Water solar collectors are often implemented for domestic hot water, heating or industrial processes and already have a place on the market. A promising system which is not yet widely known is represented by air solar collectors that could represent an efficient way to use the solar energy with a lower investment cost, a system that can be used in order to preheat the fresh air required for heating, drying, or to maintain a minimum temperature during winter. This paper presents a comprehensive literature review on air solar collectors used mainly in buildings, acting as a solar wall. Air solar collectors are roughly classified into two types: glazed and opaque. The present study comprises the solar collector classification, applications and their main parameters with a special focus on opaque solar collectors.

Effect of dye extracting solvents and sensitization time on photovoltaic performance of natural dye sensitized solar cells

NASA Astrophysics Data System (ADS)

Hossain, Md. Khalid; Pervez, M. Firoz; Mia, M. N. H.; Mortuza, A. A.; Rahaman, M. S.; Karim, M. R.; Islam, Jahid M. M.; Ahmed, Farid; Khan, Mubarak A.

In this study, natural dye sensitizer based solar cells were successfully fabricated and photovoltaic performance was measured. Sensitizer (turmeric) sources, dye extraction process, and photoanode sensitization time of the fabricated cells were analyzed and optimized. Dry turmeric, verdant turmeric, and powder turmeric were used as dye sources. Five distinct types of solvents were used for extraction of natural dye from turmeric. Dyes were characterized by UV-Vis spectrophotometric analysis. The extracted turmeric dye was used as a sensitizer in the dye sensitized solar cell's (DSSC) photoanode assembly. Nano-crystalline TiO2 was used as a film coating semiconductor material of the photoanode. TiO2 films on ITO glass substrate were prepared by simple doctor blade technique. The influence of the different parameters VOC, JSC, power density, FF, and η% on the photovoltaic characteristics of DSSCs was analyzed. The best energy conversion performance was obtained for 2 h adsorption time of dye on TiO2 nano-porous surface with ethanol extracted dye from dry turmeric.

Single-step colloidal quantum dot films for infrared solar harvesting

NASA Astrophysics Data System (ADS)

Kiani, Amirreza; Sutherland, Brandon R.; Kim, Younghoon; Ouellette, Olivier; Levina, Larissa; Walters, Grant; Dinh, Cao-Thang; Liu, Mengxia; Voznyy, Oleksandr; Lan, Xinzheng; Labelle, Andre J.; Ip, Alexander H.; Proppe, Andrew; Ahmed, Ghada H.; Mohammed, Omar F.; Hoogland, Sjoerd; Sargent, Edward H.

2016-10-01

Semiconductors with bandgaps in the near- to mid-infrared can harvest solar light that is otherwise wasted by conventional single-junction solar cell architectures. In particular, colloidal quantum dots (CQDs) are promising materials since they are cost-effective, processed from solution, and have a bandgap that can be tuned into the infrared (IR) via the quantum size effect. These characteristics enable them to harvest the infrared portion of the solar spectrum to which silicon is transparent. To date, IR CQD solar cells have been made using a wasteful and complex sequential layer-by-layer process. Here, we demonstrate ˜1 eV bandgap solar-harvesting CQD films deposited in a single step. By engineering a fast-drying solvent mixture for metal iodide-capped CQDs, we deposited active layers greater than 200 nm in thickness having a mean roughness less than 1 nm. We integrated these films into infrared solar cells that are stable in air and exhibit power conversion efficiencies of 3.5% under illumination by the full solar spectrum, and 0.4% through a simulated silicon solar cell filter.

A two-dimensional DNA lattice implanted polymer solar cell.

PubMed

Lee, Keun Woo; Kim, Kyung Min; Lee, Junwye; Amin, Rashid; Kim, Byeonghoon; Park, Sung Kye; Lee, Seok Kiu; Park, Sung Ha; Kim, Hyun Jae

2011-09-16

A double crossover tile based artificial two-dimensional (2D) DNA lattice was fabricated and the dry-wet method was introduced to recover an original DNA lattice structure in order to deposit DNA lattices safely on the organic layer without damaging the layer. The DNA lattice was then employed as an electron blocking layer in a polymer solar cell causing an increase of about 10% up to 160% in the power conversion efficiency. Consequently, the resulting solar cell which had an artificial 2D DNA blocking layer showed a significant enhancement in power conversion efficiency compared to conventional polymer solar cells. It should be clear that the artificial DNA nanostructure holds unique physical properties that are extremely attractive for various energy-related and photonic applications.

The Value of Concentrating Solar Power and Thermal Energy Storage

DOE PAGES

Sioshansi, Ramteen; Denholm, Paul

2010-06-14

Our paper examines the value of concentrating solar power (CSP) and thermal energy storage (TES) in a number of regions in the southwestern United States. Our analysis also shows that TES can increase the value of CSP by allowing more thermal energy from a CSP plant's solar field to be used, allowing a CSP plant to accommodate a larger solar field, and by allowing CSP generation to be shifted to hours with higher energy prices. We also analyze the sensitivity of this value to a number of factors, including the optimization period, price and solar forecasting, ancillary service sales, andmore » dry cooling of the CSP plant, and also estimate the capacity value of a CSP plant with TES. We further discuss the value of CSP plants and TES net of capital costs.« less

40 CFR 86.158-00 - Supplemental Federal Test Procedures; overview.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Procedures (SFTP). These test procedures consist of two separable test elements: A sequence of vehicle.../pound of dry air (approximately 40 percent relative humidity), and a solar heat load intensity of 850 W...

40 CFR 86.158-00 - Supplemental Federal Test Procedures; overview.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Procedures (SFTP). These test procedures consist of two separable test elements: A sequence of vehicle.../pound of dry air (approximately 40 percent relative humidity), and a solar heat load intensity of 850 W...

40 CFR 86.158-00 - Supplemental Federal Test Procedures; overview.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Procedures (SFTP). These test procedures consist of two separable test elements: A sequence of vehicle.../pound of dry air (approximately 40 percent relative humidity), and a solar heat load intensity of 850 W...

40 CFR 86.158-00 - Supplemental Federal Test Procedures; overview.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Procedures (SFTP). These test procedures consist of two separable test elements: A sequence of vehicle.../pound of dry air (approximately 40 percent relative humidity), and a solar heat load intensity of 850 W...

Remote sensing of total dry-matter accumulation in winter wheat

NASA Technical Reports Server (NTRS)

Tucker, C. J.; Holben, B. N.; Elgin, J. H., Jr.; Mcmurtrey, J. E., III (Principal Investigator)

1980-01-01

The author has identified the following significant results. Red and photographic-infrared spectral data collected on 21 dates over the growing season with a hand-held radiometer was quantitatively correlated with total dry-matter accumulation in winter wheat. The spectral data were found to be highly related to vigor and condition of the plant canopy. Two periods of drought stress and subsequent recovery from it were readily apparent in the spectral data. Simple ratios of the spectral data compensated for variations in solar intensities and, when integrated over the growing season, explained 79% of the variation in total above-ground accumulation of dry matter.

Anti-reflection coatings on large area glass sheets

NASA Technical Reports Server (NTRS)

Pastirik, E.

1980-01-01

Antireflective coatings which may be suitable for use on the covers of photovoltaic solar modules can be easily produced by a dipping process. The coatings are applied to glass by drawing sheets of glass vertically out of dilute aqueous sodium silicate solutions at a constant speed, allowing the adherent liquid film to dry, then exposing the dried film to concentrated sulfuric acid, followed by a water rinse and dry. The process produces coatings of good optical performance (96.7 percent peak transmission at 0.540 mu M wavelength) combined with excellent stain and soil resistance, and good resistance to abrasion. The process is reproduceable and easily controlled.

Estimated winter wheat yield from crop growth predicted by LANDSAT

NASA Technical Reports Server (NTRS)

Kanemasu, E. T.

1977-01-01

An evapotranspiration and growth model for winter wheat is reported. The inputs are daily solar radiation, maximum temperature, minimum temperature, precipitation/irrigation and leaf area index. The meteorological data were obtained from National Weather Service while LAI was obtained from LANDSAT multispectral scanner. The output provides daily estimates of potential evapotranspiration, transpiration, evaporation, soil moisture (50 cm depth), percentage depletion, net photosynthesis and dry matter production. Winter wheat yields are correlated with transpiration and dry matter accumulation.

Photoelectrochemical cells for conversion of solar energy to electricity and methods of their manufacture

DOEpatents

Skotheim, Terje

1984-04-10

A photoelectric device is disclosed which comprises first and second layers of semiconductive material, each of a different bandgap, with a layer of dry solid polymer electrolyte disposed between the two semiconductor layers. A layer of a polymer blend of a highly conductive polymer and a solid polymer electrolyte is further interposed between the dry solid polymer electrolyte and the first semiconductor layer. A method of manufacturing such devices is also disclosed.

[Effect of outer space factors on lettuce seeds (Lactuca sativa) flown on "Kosmos" biosatellites].

PubMed

Nevzgodina, L V; Maksimova, E N; Akatov, Iu A; Kaminskaia, E V; Marennyĭ, A M

1990-01-01

The effect of cosmic radiation on air-dry lettuce (Lactuca sativa) seeds was investigated. It was attempted to discriminate the effects of cosmic ionizing radiation per se and its combination with solar light radiation. It was found that the number of aberrant cells in the seeds exposed to solar light was smaller than that of cells chielded with 0.0008 to 0.0035 g/cm2 foil which could be attributed to photoreactivity.

Rainfall variability in southern Spain on decadal to centennial time scales

NASA Astrophysics Data System (ADS)

Rodrigo, F. S.; Esteban-Parra, M. J.; Pozo-Vázquez, D.; Castro-Díez, Y.

2000-06-01

In this work a long rainfall series in Andalusia (southern Spain) is analysed. Methods of historical climatology were used to reconstruct a 500-year series from historical sources. Different statistical tools were used to detect and characterize significant changes in this series. Results indicate rainfall fluctuations, without abrupt changes, in the following alternating dry and wet phases: 1501-1589 dry, 1590-1649 wet, 1650-1775 dry, 1776-1937 wet and 1938-1997 dry. Possible causal mechanisms are discussed, emphasizing the important contribution of the North Atlantic Oscillation (NAO) to rainfall variability in the region. Solar activity is discussed in relation to the Maunder Minimum period, and finally the past and present are compared. Results indicate that the magnitude of fluctuations is similar in the past and present.

Melatonin content of pepper and tomato fruits: effects of cultivar and solar radiation.

PubMed

Riga, Patrick; Medina, Sonia; García-Flores, Libia Alejandra; Gil-Izquierdo, Ángel

2014-08-01

We evaluated the effect of cultivar and solar radiation on the melatonin content of Capsicum annuum (pepper) and Solanum lycopersicum (tomato) fruits. The melatonin content of red pepper fruits ranged from 31 to 93ngg(-1) (dry weight). The melatonin content of tomato ranged from 7.5 to 250ngg(-1) (dry weight). We also studied the effect of ripeness on melatonin content and identified one group of pepper cultivars in which the melatonin content increased as the fruit ripened and another in which it decreased as the fruit ripened. Under shade conditions, the melatonin content in most of tomato cultivars tended to increase (up to 135%), whereas that of most pepper cultivars decreased (to 64%). Overall, the results also demonstrated that the melatonin content of the fruits was not related to carbon fluxes from leaves. Copyright © 2014 Elsevier Ltd. All rights reserved.

Influence of dust and mud on the optical, chemical, and mechanical properties of a pv protective glass

NASA Astrophysics Data System (ADS)

Yilbas, Bekir Sami.; Ali, Haider; Khaled, Mazen M.; Al-Aqeeli, Nasser; Abu-Dheir, Numan; Varanasi, Kripa K.

2015-10-01

Recent developments in climate change have increased the frequency of dust storms in the Middle East. Dust storms significantly influence the performances of solar energy harvesting systems, particularly (photovoltaic) PV systems. The characteristics of the dust and the mud formed from this dust are examined using various analytical tools, including optical, scanning electron, and atomic force microscopies, X-ray diffraction, energy spectroscopy, and Fourier transform infrared spectroscopy. The adhesion, cohesion and frictional forces present during the removal of dry mud from the glass surface are determined using a microtribometer. Alkali and alkaline earth metal compounds in the dust dissolve in water to form a chemically active solution at the glass surface. This solution modifies the texture of the glass surface, thereby increasing the microhardness and decreasing the transmittance of the incident optical radiation. The force required to remove the dry mud from the glass surface is high due to the cohesive forces that result from the dried mud solution at the interface between the mud and the glass. The ability altering the characteristics of the glass surface could address the dust/mud-related limitations of protective surfaces and has implications for efficiency enhancements in solar energy systems.

Influence of dust and mud on the optical, chemical, and mechanical properties of a pv protective glass.

PubMed

Yilbas, Bekir Sami; Ali, Haider; Khaled, Mazen M; Al-Aqeeli, Nasser; Abu-Dheir, Numan; Varanasi, Kripa K

2015-10-30

Recent developments in climate change have increased the frequency of dust storms in the Middle East. Dust storms significantly influence the performances of solar energy harvesting systems, particularly (photovoltaic) PV systems. The characteristics of the dust and the mud formed from this dust are examined using various analytical tools, including optical, scanning electron, and atomic force microscopies, X-ray diffraction, energy spectroscopy, and Fourier transform infrared spectroscopy. The adhesion, cohesion and frictional forces present during the removal of dry mud from the glass surface are determined using a microtribometer. Alkali and alkaline earth metal compounds in the dust dissolve in water to form a chemically active solution at the glass surface. This solution modifies the texture of the glass surface, thereby increasing the microhardness and decreasing the transmittance of the incident optical radiation. The force required to remove the dry mud from the glass surface is high due to the cohesive forces that result from the dried mud solution at the interface between the mud and the glass. The ability altering the characteristics of the glass surface could address the dust/mud-related limitations of protective surfaces and has implications for efficiency enhancements in solar energy systems.

Radiative effects of biomass burning aerosols and cloudiness on seasonal carbon cycle in the Amazon region

NASA Astrophysics Data System (ADS)

Moreira, D. S.; Longo, K.; Freitas, S.; Mercado, L. M.; Miller, J. B.; Rosario, N. M. E. D.; Gatti, L.; Yamasoe, M. A.

2017-12-01

The Amazon region is characterized by high cloudiness, mainly due to convective clouds during most of the year due to the high humidity, and heat availability. However, during the Austral winter, the northward movement of the inter-tropical convergence zone (ITCZ) from its climatological position, significantly reducing cloudiness and precipitation, facilitating vegetation fires. Consequently, during these dry months, biomass burning aerosols contribute to relatively high values of aerosol optical depth (AOD) in Amazonia, typically exceeding 1.0 in the 550 nm wavelength. Both clouds and aerosols scatter solar radiation, reducing the direct irradiance and increasing the diffuse fraction that reaches the surface, decreasing near surface temperature and increasing photosynthetically active radiation (PAR) availability. This, in turn, affects energy and CO2 fluxes within the vegetation canopy. We applied an atmospheric model fully coupled to terrestrial carbon cycle model to assess the relative impact of biomass burning aerosols and clouds on CO2 fluxes in the Amazon region. Our results indicate that during most of the year, gross primary productivity (GPP) is high mainly due to high soil moisture and high values of the diffuse fraction of solar irradiation due to cloudiness. Therefore, heterotrophic and autotrophic respiration are both high, increasing the NEE values (i.e. reducing the net land sink). On the other hand, during the dry season, with a significant reduction of cloudiness, the biomass burning aerosol is mainly responsible for the increase in the diffuse fraction of solar irradiation and the GPP of the forest. However, the low soil moisture during the dry season, especially in the eastern Amazon, reduces heterotrophic and autotrophic respiration and thus compensates for reduced GPP compared to the wet season. Different reasons, an anthropogenic one (human induced fires during the dry season) and a natural one (cloudiness), lead to a somewhat stable value of NEE all year long in Amazonia.

Comparison of the Morphology Development of Polymer-Fullerene and Polymer-Polymer Solar Cells during Solution-Shearing Blade Coating

DOE PAGES

Gu, Xiaodan; Yan, Hongping; Kurosawa, Tadanori; ...

2016-08-22

Here in this work, the detailed morphology studies of polymer poly(3-hexylthiophene-2,5-diyl) (P3HT):fullerene(PCBM) and polymer(P3HT):polymer naphthalene diimide thiophene (PNDIT) solar cell are presented to understand the challenge for getting high performance all-polymer solar cells. The in situ X-ray scattering and optical interferometry and ex situ hard and soft X-ray scattering and imaging techniques are used to characterize the bulk heterojunction (BHJ) ink during drying and in dried state. The crystallization of P3HT polymers in P3HT:PCBM bulk heterojunction shows very different behavior compared to that of P3HT:PNDIT BHJ due to different mobilities of P3HT in the donor:acceptor glass. Supplemented by the exmore » situ grazing incidence X-ray diffraction and soft X-ray scattering, PNDIT has a lower tendency to form a mixed phase with P3HT than PCBM, which may be the key to inhibit the donor polymer crystallization process, thus creating preferred small phase separation between the donor and acceptor polymer.« less

Annually and monthly resolved solar irradiance and atmospheric temperature data across the Hawaiian archipelago from 1998 to 2015 with interannual summary statistics.

PubMed

Bryce, Richard; Losada Carreño, Ignacio; Kumler, Andrew; Hodge, Bri-Mathias; Roberts, Billy; Brancucci Martinez-Anido, Carlo

2018-08-01

This article contains data and summary statistics of solar irradiance and dry bulb temperature across the Hawaiian archipelago resolved on a monthly basis and spanning years 1998-2015. This data was derived in association with an article titled "Consequences of Neglecting the Interannual Variability of the Solar Resource: A Case Study of Photovoltaic Power Among the Hawaiian Islands" (Bryce et al., 2018 [7]). The solar irradiance data is presented in terms of Direct Normal Irradiance (DNI), Diffuse Horizontal Irradiance (DHI), and Global Horizontal Irradiance (GHI) and was obtained from the satellite-derived data contained in the National Solar Radiation Database (NSRDB). The temperature data is also obtained from this source. We have processed the NSRDB data and compiled these monthly resolved data sets, along with interannual summary statistics including the interannual coefficient of variability.

Recent developments in drying of food products

NASA Astrophysics Data System (ADS)

Valarmathi, T. N.; Sekar, S.; Purushothaman, M.; Sekar, S. D.; Rama Sharath Reddy, Maddela; Reddy, Kancham Reddy Naveen Kumar

2017-05-01

Drying is a dehydration process to preserve agricultural products for long period usage. The most common and cheapest method is open sun drying in which the products are simply laid on ground, road, mats, roof, etc. But the open sun drying has some disadvantages like dependent on good weather, contamination by dust, birds and animals consume a considerable quantity, slow drying rate and damages due to strong winds and rain. To overcome these difficulties solar dryers are developed with closed environment for drying agricultural products effectively. To obtain good quality food with reduced energy consumption, selection of appropriate drying process and proper input parameters is essential. In recent years several researchers across the world have developed new drying systems for improving the product quality, increasing the drying rate, decreasing the energy consumption, etc. Some of the new systems are fluidized bed, vibrated fluidized bed, desiccant, microwave, vacuum, freeze, infrared, intermittent, electro hydrodynamic and hybrid dryers. In this review the most recent progress in the field of drying of agricultural food products such as new methods, new products and modeling and optimization techniques has been presented. Challenges and future directions are also highlighted. The review will be useful for new researchers entering into this ever needed and ever growing field of engineering.

Sewage sludge drying by energy recovery from OFMSW composting: Preliminary feasibility evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rada, Elena Cristina; Ragazzi, Marco; Villotti, Stefano

2014-05-01

Highlights: • The aim is to support the drying of sewage sludge, using a solar greenhouse. • The system allows the exploitation of heat available from OFMSW aerobic process. • Another aim is to face the problem of OFMSW treatment, in particular food waste. • Energy and mass balances are presented for a case study. - Abstract: In this paper an original energy recovery method from composting is analyzed. The integrated system exploits the heat available from the aerobic biochemical process in order to support the drying of sewage sludge, using a specific solar greenhouse. The aim is to tacklemore » the problem of organic waste treatment, with specific regard to food waste. This is done by optimizing the energy consumption of the aerobic process of composting, using the heat produced to solve a second important waste management problem such as the sewage waste treatment. Energy and mass balances are presented in a preliminary feasibility study. Referring to a composting plant with a capacity of 15,000 t/y of food waste, the estimation of the power from recovered heat for the entire plant resulted about 42 kW. The results demonstrated that the energy recoverable can cover part of the heat necessary for the treatment of sludge generated by the population served by the composting plant (in terms of food waste and green waste collection). The addition of a renewable source such as solar energy could cover the residual energy demand. The approach is presented in detail in order for it to be replicated in other case studies or at full scale applications.« less

Heat waves and jet stream relations - nature of dry and wet shifts around the 2.8 kyr BP event in Central Europe

NASA Astrophysics Data System (ADS)

Slowinski, M. M.; Persoiu, A.; Slowinska, S.; Marcisz, K.; Ionita, M.; Lamentowicz, M.

2017-12-01

Solar insolation was the main driver of N Hemisphere storm tracks changes, with significant impacts on European climate variability during the Holocene. Consequently, the Homeric solar minimum, which occurred between 2,750 and 2,550 cal BP, was characterized by cooling and increase in wind strength and humidity in W Europe. In contrast, environmental reconstructions from Central and E Europe show that the climatic changes during this period were often more complex, with increased hydrological instability and a shift towards drier conditions. These contrasting conditions could be explained by the blocking in a stationary position of a high-pressure system above Central and E Europe as a result of the behavior of the jet stream. In order to understand how these changes in the behavior of the jet stream were acting in the past, we have analyzed a modern analogue to better understand the climatic map of Europe during the Homeric minimum of the 9th century BC. Thus, in summer 2015, a northward extending meander of the jet stream led to dry and hot conditions in C Europe, blocking the transport of Atlantic-sourced moisture eastwards and leading to increased precipitation in W Europe. Contrary, in 2013, the position of the high-pressure cells associated with the meandering of the jet-stream was located over W Russia and E Europe (both affected by heat waves resulting from meridional advection of dry/hot air), leading to more Rossby waves breaking over C Europe and delivering record amounts of precipitation. To test whether a similar mechanism could act on longer times scales, we have analyzed two high-resolution palaeoclimate datasets from E Europe (Rąbień peatbog, Poland and Scăriloara Ice Cave, Romania), located in areas with both N Atlantic and Mediterranean climatic influences. At the time of the Homeric Solar Minimum, warm climatic conditions dominated in SE Europe, with advection of warm and dry air from the Mediterranean. W Europe was rather wet around that time and these contrasting conditions could have been the result of blocking conditions over C Europe, induced by a solar-influenced strongly meandering jet-stream. Our recent monitoring observation and paleoclimate data support studies that presents link between arctic polar vortex, jet streams, sea-ice formation in the Arctic and climate variability in Europe.

Advanced Antireflection Coatings for High-Performance Solar Energy Applications

NASA Technical Reports Server (NTRS)

Pan, Noren

2015-01-01

Phase II objectives: Develop and refine antireflection coatings incorporating lanthanum titanate as an intermediate refractive index material; Investigate wet/dry thermal oxidation of aluminum containing semiconductor compounds as a means of forming a more transparent window layer with equal or better optical properties than its unoxidized form; Develop a fabrication process that allows integration of the oxidized window layer and maintains the necessary electrical properties for contacting the solar cell; Conduct an experimental demonstration of the best candidates for improved antireflection coatings.

Chemo-Mechanical Characteristics of Mud Formed from Environmental Dust Particles in Humid Ambient Air

PubMed Central

Hassan, Ghassan; Yilbas, B. S.; Said, Syed A. M.; Al-Aqeeli, N.; Matin, Asif

2016-01-01

Mud formed from environmental dust particles in humid ambient air significantly influences the performance of solar harvesting devices. This study examines the characterization of environmental dust particles and the chemo-mechanics of dry mud formed from dust particles. Analytical tools, including scanning electron microscopy, atomic force microscopy, energy dispersive spectroscopy, particle sizing, and X-ray diffraction, are used to characterize dry mud and dust particles. A micro/nano tribometer is used to measure the tangential force and friction coefficient while tensile tests are carried out to assess the binding forces of dry mud pellets. After dry mud is removed, mud residuals on the glass surface are examined and the optical transmittance of the glass is measured. Dust particles include alkaline compounds, which dissolve in water condensate and form a mud solution with high pH (pH = 7.5). The mud solution forms a thin liquid film at the interface of dust particles and surface. Crystals form as the mud solution dries, thus, increasing the adhesion work required to remove dry mud from the surface. Optical transmittance of the glass is reduced after dry mud is removed due to the dry mud residue on the surface. PMID:27445272

Chemo-Mechanical Characteristics of Mud Formed from Environmental Dust Particles in Humid Ambient Air.

PubMed

Hassan, Ghassan; Yilbas, B S; Said, Syed A M; Al-Aqeeli, N; Matin, Asif

2016-07-22

Mud formed from environmental dust particles in humid ambient air significantly influences the performance of solar harvesting devices. This study examines the characterization of environmental dust particles and the chemo-mechanics of dry mud formed from dust particles. Analytical tools, including scanning electron microscopy, atomic force microscopy, energy dispersive spectroscopy, particle sizing, and X-ray diffraction, are used to characterize dry mud and dust particles. A micro/nano tribometer is used to measure the tangential force and friction coefficient while tensile tests are carried out to assess the binding forces of dry mud pellets. After dry mud is removed, mud residuals on the glass surface are examined and the optical transmittance of the glass is measured. Dust particles include alkaline compounds, which dissolve in water condensate and form a mud solution with high pH (pH = 7.5). The mud solution forms a thin liquid film at the interface of dust particles and surface. Crystals form as the mud solution dries, thus, increasing the adhesion work required to remove dry mud from the surface. Optical transmittance of the glass is reduced after dry mud is removed due to the dry mud residue on the surface.

Device physics of Cu(In,Ga)Se2 solar cells for long-term operation

NASA Astrophysics Data System (ADS)

Nishinaga, J.; Shibata, H.

2017-02-01

The degradation mechanism of Cu(In,Ga)Se2 (CIGS) solar cells on exposure to air has been investigated. Exposure to air at room temperature slightly reduces the conversion efficiency of CIGS solar cells, and the conversion efficiency decreases significantly under damp heat testing at 85 °C and 85% relative humidity due to low shunt resistance. On the other hand, shunt resistance increases after dry nitrogen heating. Therefore, oxygen and humidity should degenerate the solar cell performance. The low shunt resistance and conversion efficiency are completely recovered after removing the side edges of the CIGS solar cells by mechanical scribing. These results suggest that low-resistive layers are formed on the sidewalls of the solar cells during damp heat testing. The low-resistive layers on the sidewalls are identified to be molybdenum oxides and sodium molybdate by Auger electron spectroscopy. After etching the oxides on the sidewalls by alkaline solution, the saturation current density and ideality factor are confirmed to be improved. These results suggest that metal oxides on the sidewalls of CIGS solar cells may act as recombination centers.

40 CFR 86.158-08 - Supplemental Federal Test Procedures; overview.

Code of Federal Regulations, 2011 CFR

2011-07-01

... analytical system shall be configured to calculate THC for the US06 City phase and the US06 Highway phase as... °F, 100 grains of water/pound of dry air (approximately 40 percent relative humidity), and a solar...

40 CFR 86.158-08 - Supplemental Federal Test Procedures; overview.

Code of Federal Regulations, 2010 CFR

2010-07-01

... analytical system shall be configured to calculate THC for the US06 City phase and the US06 Highway phase as... °F, 100 grains of water/pound of dry air (approximately 40 percent relative humidity), and a solar...

Water transport in limestone by X-ray CAT scanning

USGS Publications Warehouse

Mossoti, Victor G.; Castanier, Louis M.

1989-01-01

The transport of water through the interior of Salem limestone test briquettes can be dynamically monitored by computer aided tomography (commonly called CAT scanning in medical diagnostics). Most significantly, unless evaporation from a particular face of the briquette is accelerated by forced air flow (wind simulation), the distribution of water in the interior of the briquette remains more or less uniform throughout the complete drying cycle. Moreover, simulated solar illumination of the test briquette does not result in the production of significant water gradients in the briquette under steady-state drying conditions.

Manufacture of reconstruction-bricks in Mexico

NASA Astrophysics Data System (ADS)

Rojas-Valencia, Ma. Neftalí; Penagos, Armando Aguilar; Rojas, Denise Y. Fernández; López, Alberto López; Gálves, David Morillón

2017-12-01

In Mexico, around 33.600 tons of construction wastes are generated every day, Mexico City contributing for around tons/day, with fewer than 1.000 tons/day being sent to be recycled. For that reason the purpose of this study was to manufacture sustainable bricks, based on three types of wastes generated in the building industry: wood cutting residues, wastes from the excavation process (From Coapa and Cuautlancingo, Puebla, Mexico) and recycled aggregates. Water was added as kneading material, and Opuntia ficus-indica (mucilage) was supplemented as natural additive to improve the workability of the mixtures. Conventional firing process was substituted by drying in a solar drying chamber. Nine mixtures were prepared using 62% excavation wastes, 4% wood cutting residues and 11%, 17% and 34% recycled aggregates. These mixtures were classified in two groups depending on their granulometry: the first one denominated cementitious recycled aggregates only having granulometry from 25.4 mm, 9.52 mm to 6.35 mm to fines and the second group denominated all in one recycled aggregates having granulometry of 6.35 mm to fines. The quality of the sustainable bricks was evaluated according to compressive strength and water absorption parameters. The results of nine mixtures showed that the reconstruction-bricks manufactured with the mixture seven consisting of 9.52 mm and 6.35 mm construction residues (all in one) fines presented the highest strength values, lowest maximum initial absorption (4 g/min) compared to the norm NMX-C-037-ONNCCE-2013 which establishes that the maximum limit for walls exposed to the outside is 5 g/min. Using a solar desiccator made from construction residues, the bricks were dried in 11 days, the maximum temperature was 76 °C and the maximum solar radiation captured was 733.4 W/m2.

UV-B radiation and photosynthetic irradiance acclimate eggplant for outdoor exposure

NASA Technical Reports Server (NTRS)

Latimer, J. G.; Mitchell, C. A.; Mitchell, G. A.

1987-01-01

Treatment of greenhouse-grown eggplant (Solanum melongena L. var. esculentum Nees. 'Burpee's Black Beauty') seedlings with supplemental photosynthetically active radiation from cool-white fluorescent lamps increased growth of plants subsequently transferred outdoors relative to growth of plants that received no supplemental radiation or were shaded to 45% of solar irradiation in the greenhouse before transfer outdoors. Eggplant seedlings transferred outdoors were placed under plastic tarps either to provide relative protection from solar ultraviolet-B (UV-B) radiation (280-315 nm) using Mylar film or to allow exposure to UV-B using cellulose acetate. Protection of seedlings from UV-B radiation resulted in greater leaf expansion than for UV-B-exposed seedlings, but no change in leaf or shoot dry weight occurred after 9 days of treatment. Specific leaf weight increased in response to UV-B exposure outdoors. Exposure of eggplant to UV-B radiation from fluorescent sunlamps in the greenhouse also decreased leaf expansion and leaf and shoot dry weight gain after 5 days of treatment. However, there were no differences in leaf or shoot dry weight relative to control plants after 12 days of UV-B treatment, indicating that UV-B treated plants had acclimated to the treatment and actually had caught up with non-UV-B-irradiated plants in terms of growth.

Influence of dust and mud on the optical, chemical, and mechanical properties of a pv protective glass

PubMed Central

Yilbas, Bekir Sami.; Ali, Haider; Khaled, Mazen M.; Al-Aqeeli, Nasser; Abu-Dheir, Numan; Varanasi, Kripa K.

2015-01-01

Recent developments in climate change have increased the frequency of dust storms in the Middle East. Dust storms significantly influence the performances of solar energy harvesting systems, particularly (photovoltaic) PV systems. The characteristics of the dust and the mud formed from this dust are examined using various analytical tools, including optical, scanning electron, and atomic force microscopies, X-ray diffraction, energy spectroscopy, and Fourier transform infrared spectroscopy. The adhesion, cohesion and frictional forces present during the removal of dry mud from the glass surface are determined using a microtribometer. Alkali and alkaline earth metal compounds in the dust dissolve in water to form a chemically active solution at the glass surface. This solution modifies the texture of the glass surface, thereby increasing the microhardness and decreasing the transmittance of the incident optical radiation. The force required to remove the dry mud from the glass surface is high due to the cohesive forces that result from the dried mud solution at the interface between the mud and the glass. The ability altering the characteristics of the glass surface could address the dust/mud-related limitations of protective surfaces and has implications for efficiency enhancements in solar energy systems. PMID:26514102

UV-B radiation and photosynthetic irradiance acclimate eggplant for outdoor exposure.

PubMed

Latimer, J G; Mitchell, C A; Mitchell, G A

1987-06-01

Treatment of greenhouse-grown eggplant (Solanum melongena L. var. esculentum Nees. 'Burpee's Black Beauty') seedlings with supplemental photosynthetically active radiation from cool-white fluorescent lamps increased growth of plants subsequently transferred outdoors relative to growth of plants that received no supplemental radiation or were shaded to 45% of solar irradiation in the greenhouse before transfer outdoors. Eggplant seedlings transferred outdoors were placed under plastic tarps either to provide relative protection from solar ultraviolet-B (UV-B) radiation (280-315 nm) using Mylar film or to allow exposure to UV-B using cellulose acetate. Protection of seedlings from UV-B radiation resulted in greater leaf expansion than for UV-B-exposed seedlings, but no change in leaf or shoot dry weight occurred after 9 days of treatment. Specific leaf weight increased in response to UV-B exposure outdoors. Exposure of eggplant to UV-B radiation from fluorescent sunlamps in the greenhouse also decreased leaf expansion and leaf and shoot dry weight gain after 5 days of treatment. However, there were no differences in leaf or shoot dry weight relative to control plants after 12 days of UV-B treatment, indicating that UV-B treated plants had acclimated to the treatment and actually had caught up with non-UV-B-irradiated plants in terms of growth.

Quality Controlled Radiosonde Profile from MC3E

DOE Data Explorer

Toto, Tami; Jensen, Michael

2014-11-13

The sonde-adjust VAP produces data that corrects documented biases in radiosonde humidity measurements. Unique fields contained within this datastream include smoothed original relative humidity, dry bias corrected relative humidity, and final corrected relative humidity. The smoothed RH field refines the relative humidity from integers - the resolution of the instrument - to fractions of a percent. This profile is then used to calculate the dry bias corrected field. The final correction fixes a time-lag problem and uses the dry-bias field as input into the algorithm. In addition to dry bias, solar heating is another correction that is encompassed in the final corrected relative humidity field. Additional corrections were made to soundings at the extended facility sites (S0*) as necessary: Corrected erroneous surface elevation (and up through rest of height of sounding), for S03, S04 and S05. Corrected erroneous surface pressure at Chanute (S02).

Integrated solar thermochemical reaction system for steam methane reforming

DOE PAGES

Zheng, Feng; Diver, Rich; Caldwell, Dustin D.; ...

2015-06-05

Solar-aided upgrade of the energy content of fossil fuels, such as natural gas, can provide a near-term transition path towards a future solar-fuel economy and reduce carbon dioxide emission from fossil fuel consumption. Both steam and dry reforming a methane-containing fuel stream have been studied with concentrated solar power as the energy input to drive the highly endothermic reactions but the concept has not been demonstrated at a commercial scale. Under a current project with the U.S. Department of Energy, PNNL is developing an integrated solar thermochemical reaction system that combines solar concentrators with micro- and meso-channel reactors and heatmore » exchangers to accomplish more than 20% solar augment of methane higher heating value. The objective of our three-year project is to develop and prepare for commercialization such solar reforming system with a high enough efficiency to serve as the frontend of a conventional natural gas (or biogas) combined cycle power plant, producing power with a levelized cost of electricity less than 6¢/kWh, without subsidies, by the year 2020. In this paper, we present results from the first year of our project that demonstrated a solar-to-chemical energy conversion efficiency as high as 69% with a prototype reaction system.« less

Energy for agriculture: a computerized information retrieval system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stout, B A; Myers, C A

1979-12-01

This bibliography contains 2613 citations to the literature for 1973 through May 1979. Some of the subjects covered include: accounting, agriculture, animal production, conservation, drying, fertilizer, food processing, greenhouses, home, international, irrigation, organic, solar, storage, tillage, and wind. Author and keyword indexes are included. (MHR)

Builders Challenge High Performance Builder Spotlight - Artistic Homes, Albuquerque, NM

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2009-01-01

Building America Builders Challenge fact sheet on Artistic Homes of Albuquerque, New Mexico. Describes the first true zero E-scale home in a hot-dry climate with ducts inside, R-50 attic insulation, roof-mounted photovoltaic power system, and solar thermal water heating.

Enhancement of growth and lipid production from microalgae using fluorescent paint under the solar radiation.

PubMed

Seo, Yeong Hwan; Cho, Changsoon; Lee, Jung-Yong; Han, Jong-In

2014-12-01

Solar radiation has intensity that is too high to inhibit microalgae activity and is composed of wide light spectrum including ultraviolet (UV) range which cannot be utilized for microalgae. For these reasons, the modification of solar radiation is required for effective microalgae cultivation, and to do that, fluorescent paint was used for not only blocking excessive solar energy but also converting UV to visible light. With fluorescent aqueous layer, microalgae was protected from photoinhibition and could grow well, but there was difference in growth and lipid accumulation efficiencies depending on the color; maximum dry weight of 1.7 g/L was achieved in red paint, whereas best lipid content of 30% was obtained in blue one. This phenomenon was due to the different light spectrum made by colors. With simple process using fluorescent paint, modification of light was successfully done and allowing microalgae to grow under strong radiation such as solar radiation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Thermal analysis of insulated north-wall greenhouse with solar collector under passive mode

NASA Astrophysics Data System (ADS)

Chauhan, Prashant Singh; Kumar, Anil

2018-04-01

An insulated north wall greenhouse dryer has been fabricated and tested for no-load condition under passive mode. Testing has been conducted in two different cases. Case-I is considered for solar collector kept inside the dryer and Case-II is dryer without solar collector. Convective heat transfer coefficient and various heat transfer dimensionless numbers with have been calculated for thermal analysis. The maximum convective heat transfer coefficient is found 52.18 W/m2°C at 14 h during the first day for Case-I. The difference of the highest convective heat transfer coefficient of both cases was 8.34 W/m2°C. Net heat gain inside room curves are uniform and smooth for Case-I, which shows the steady heat generation process due to presence of solar collector inside the dryer. Above results depicts the effectiveness of solar collector and insulated north wall. The selection of suitable crop for drying can be done by analysing article's result.

Solar energy in food processing-a critical appraisal.

PubMed

Eswara, Amruta R; Ramakrishnarao, M

2013-04-01

Increasing population and high cost of fuels have created opportunities for using alternate energies for post-harvest processing of foods. Solar food processing is an emerging technology that provides good quality foods at low or no additional fuel costs. A number of solar dryers, collectors and concentrators are currently being used for various steps in food processing and value addition. Society for Energy, Environment and Development (SEED) developed Solar Cabinet Dryer with forced circulation which has been used for dehydration and development of value added products from locally grown fruits, vegetables, leafy greens and forest produce. Drying under simulated shade conditions using UV-reducing Blue filter helps retain nutrients better. Its simple design and ease of handling makes SEED Solar Dryer an ideal choice for application of food processing in rural settings, closer to where the harvest is produced, eliminating the need for expensive transportation or storage of fresh produce. It also creates employment opportunities among the rural population, especially women. Other gadgets based on solar collectors and concentrators currently being used at various steps of food processing are reviewed.

Solarnorth '81 by Tymura Solardesigns: diverse residential, commercial and industrial projects at and above the 48th parallel in Ontario, Canada

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tymura, E.J.

1981-01-01

Solar Energy Heating Applications are On the Rise in and above the Northwestern City of Thunder Bay, on the northern shore of Lake Superior. Unique in their diversifications, the architectural commissions range from pure passive residential design thru hybrid systems; residential Greenhouse-Solarium active swimming pool and commercial hotel pool to inexpensive hybrid system for Canada's First Commercial Solar Lumber Drying Kiln; as well as combined earth sheltered with solar system design for a dormitory complex and shopping center. By May 1981, 7 buildings designed by Tymura Solardesigns in the Thunder Bay area will have been subjected to the Extreme Canadianmore » climate (10,500/sup 0/F degree days, yearly temperature maximums from -41/sup 0/F to 90/sup 0/F, and solar fractions vary from 50% to 75%, with economic payback periods ranging between 7 and 10 years.« less

UHPLC-TQ-MS Coupled with Multivariate Statistical Analysis to Characterize Nucleosides, Nucleobases and Amino Acids in Angelicae Sinensis Radix Obtained by Different Drying Methods.

PubMed

Zhu, Shaoqing; Guo, Sheng; Duan, Jin-Ao; Qian, Dawei; Yan, Hui; Sha, Xiuxiu; Zhu, Zhenhua

2017-06-01

To explore the nutrients in roots of Angelica sinensis (Angelicae Sinensis Radix, ASR), a medicinal and edible plant, and evaluate its nutritional value, a rapid and reliable UHPLC-TQ-MS method was established and used to determine the potential nutritional compounds, including nucleosides, nucleobases and amino acids, in 50 batches of ASR samples obtained using two drying methods. The results showed that ASR is a healthy food rich in nucleosides, nucleobases and amino acids, especially arginine. The total average content of nucleosides and nucleobases in all ASR samples was 3.94 mg/g, while that of amino acids reached as high as 61.79 mg/g. Principle component analysis showed that chemical profile differences exist between the two groups of ASR samples prepared using different drying methods, and the contents of nutritional compounds in samples dried with the tempering-intermittent drying processing method (TIDM) were generally higher than those dried using the traditional solar processing method. The above results suggest that ASR should be considered an ideal healthy food and TIDM could be a suitable drying method for ASR when taking nucleosides, nucleobases and amino acids as the major consideration for their known human health benefits.

40 CFR 86.127-12 - Test procedures; overview.

Code of Federal Regulations, 2010 CFR

2010-07-01

... applicable for determining emission results for vehicle exhaust emission systems designed to comply with the... dry air (approximately 40 percent relative humidity); (iii) Simulated solar heat intensity of 850 W/m2... conditioner system condenser cooling at all vehicle speeds (see § 86.161-00(e)). (3) Manufacturers have the...

40 CFR 86.127-12 - Test procedures; overview.

Code of Federal Regulations, 2011 CFR

2011-07-01

... applicable for determining emission results for vehicle exhaust emission systems designed to comply with the... dry air (approximately 40 percent relative humidity); (iii) Simulated solar heat intensity of 850 W/m2... conditioner system condenser cooling at all vehicle speeds (see § 86.161-00(e)). (3) Manufacturers have the...

76 FR 78916 - Rice Solar Energy Project Record of Decision (DOE/EIS-0439)

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-20

... Protection Plan. The Biological Resources Mitigation Implementation and Monitoring Plan will include accurate... consideration that water is a limited resource, the Project owner would use dry cooling, which avoids... markets and transmits wholesale electrical power through an integrated 17,000-circuit mile, high- voltage...

Facilitating Integrated Agricultural Technology Development through Participatory Research

ERIC Educational Resources Information Center

Otte, Pia Piroschka; Bernardo, Ricardo; Phinney, Randi; Davidsson, Henrik; Tivana, Lucas Daniel

2018-01-01

Purpose: In this paper, we discuss the role of participatory research in integrated agricultural technology development using the example of a solar fruit drying project in Mozambique.Design/Methodology/Approach: We engage in seven participatory exercises with groups of farmers from two farmers' associations in Inharrime district in Mozambique to…

Choosing Wisely When It Comes to Eye Care: Punctal Plugs for Dry Eye

MedlinePlus

... Wisely campaign is available at Choosing Wisely . Related Stories Solar Eclipse Inflicts Damage in the Shape of the Eclipse Itself Dec 08, 2017 Eye Injuries from Laundry Packets On the Rise Jun 30, 2017 New Technology Helps the Legally Blind Be More Independent Oct ...

Elucidating the effects of solar panel waste glass substitution on the physical and mechanical characteristics of clay bricks.

PubMed

Lin, Kae-Long; Huang, Long-Sheng; Shie, Je-Lueng; Cheng, Ching-Jung; Lee, Ching-Hwa; Chang, Tien-Chin

2013-01-01

This study deals with the effect of solar panel waste glass on fired clay bricks. Brick samples were heated to temperatures which varied from 700-1000 degrees C for 6 h, with a heating rate of 10 degrees C min(-1). The material properties of the resultant material were then determined, including speciation variation, loss on ignition, shrinkage, bulk density, 24-h absorption rate, compressive strength and salt crystallization. The results indicate that increasing the amount of solar panel waste glass resulted in a decrease in the water absorption rate and an increase in the compressive strength of the solar panel waste glass bricks. The 24-h absorption rate and compressive strength of the solar panel waste glass brick made from samples containing 30% solar panel waste glass sintered at 1000 degrees C all met the Chinese National Standard (CNS) building requirements for first-class brick (compressive strengths and water absorption of the bricks were 300 kg cm(-2) and 10% of the brick, respectively). The addition of solar panel waste glass to the mixture reduced the degree of firing shrinkage. The salt crystallization test and wet-dry tests showed that the addition of solar panel waste glass had highly beneficial effects in that it increased the durability of the bricks. This indicates that solar panel waste glass is indeed suitable for the partial replacement of clay in bricks.

Experimental Study of Heat Transfer Performance of Polysilicon Slurry Drying Process

NASA Astrophysics Data System (ADS)

Wang, Xiaojing; Ma, Dongyun; Liu, Yaqian; Wang, Zhimin; Yan, Yangyang; Li, Yuankui

2016-12-01

In recent years, the growth of the solar energy photovoltaic industry has greatly promoted the development of polysilicon. However, there has been little research into the slurry by-products of polysilicon production. In this paper the thermal performance of polysilicon slurry was studied in an industrial drying process with a twin-screw horizontal intermittent dryer. By dividing the drying process into several subunits, the parameters of each unit could be regarded as constant in that period. The time-dependent changes in parameters including temperature, specific heat and evaporation enthalpy were plotted. An equation for the change in the heat transfer coefficient over time was calculated based on heat transfer equations. The concept of a distribution coefficient was introduced to reflect the influence of stirring on the heat transfer area. The distribution coefficient ranged from 1.2 to 1.7 and was obtained with the fluid simulation software FLUENT, which simplified the calculation of heat transfer area during the drying process. These experimental data can be used to guide the study of polysilicon slurry drying and optimize the design of dryers for industrial processes.

Inland diatoms from the McMurdo Dry Valleys and James Ross Island, Antarctica

USGS Publications Warehouse

Esposito, R.M.M.; Spaulding, S.A.; McKnight, Diane M.; Van De Vijver, B.; Kopalova, K.; Lubinski, D.; Hall, B.; Whittaker, T.

2008-01-01

Diatom taxa present in the inland streams and lakes of the McMurdo Dry Valleys and James Ross Island, Antarctica, are presented in this paper. A total of nine taxa are illustrated, with descriptions of four new species (Luticola austroatlantica sp. nov., Luticola dolia sp. nov., Luticola laeta sp. nov., Muelleria supra sp. nov.). In the perennially ice-covered lakes of the McMurdo Dry Valleys, diatoms are confined to benthic mats within the photic zone. In streams, diatoms are attached to benthic surfaces and within the microbial mat matrix. One species, L. austroatlantica, is found on James Ross Island, of the southern Atlantic archipelago, and the McMurdo Dry Valleys. The McMurdo Dry Valley populations are at the lower range of the size spectrum for the species. Streams flow for 6-10 weeks during the austral summer, when temperatures and solar radiation allow glacial ice to melt. The diatom flora of the region is characterized by species assemblages favored under harsh conditions, with naviculoid taxa as the dominant group and several major diatom groups conspicuously absent. ?? 2008 NRC.

Tree ring based precipitation reconstruction in the south slope of the middle Qilian Mountains, northeastern Tibetan Plateau, over the last millennium

NASA Astrophysics Data System (ADS)

Sun, Junyan; Liu, Yu

2012-04-01

A tree ring (Sabina przewalskiiKom.) based millennial precipitation reconstruction on the south slope of the middle Qilian Mountains in the northeastern margin of Tibetan Plateau, China, was completed, which explains 48.5% of the variance in the instrumental precipitation from 1958 to 2004. The long-term precipitation variation patterns were confirmed on the basis of the duration, magnitude, and intensify of the multidecadal dry (wet) events. There are several stronger multidecadal dry periods, 1092-1172, 1441-1517, and 1564-1730, whereas there is only one outstanding severe wet event of 1352-1440. The variations of the precipitation reconstruction are accordant with the glacier accumulation and dust contents of Dunde ice core and also with the variations of the precipitation, runoff, Palmer Drought Severity Index, and tree ring width series in the northeastern Tibetan Plateau. The spatial extent of the great drought in the latter half of the 15th century also concentrated on the northeastern Tibetan Plateau. The moisture variations in the northeastern Tibetan Plateau are synchronous over a large spatial and temporal range in multidecadal scale for the last millennium, especially during dry periods. Wavelet analyses and comparisons with the minimal solar activity show that the precipitation variations for the last millennium may have some association with the solar activity on multidecadal to centennial scales.

Life cycle assessment of a parabolic trough concentrating solar power plant and the impacts of key design alternatives.

PubMed

Burkhardt, John J; Heath, Garvin A; Turchi, Craig S

2011-03-15

Climate change and water scarcity are important issues for today's power sector. To inform capacity expansion decisions, hybrid life cycle assessment is used to evaluate a reference design of a parabolic trough concentrating solar power (CSP) facility located in Daggett, CA, along four sustainability metrics: life cycle (LC) greenhouse gas (GHG) emissions, water consumption, cumulative energy demand (CED), and energy payback time (EPBT). This wet-cooled, 103 MW plant utilizes mined nitrates salts in its two-tank, thermal energy storage (TES) system. Design alternatives of dry-cooling, a thermocline TES, and synthetically derived nitrate salt are evaluated. During its LC, the reference CSP plant is estimated to emit 26 g of CO(2eq) per kWh, consume 4.7 L/kWh of water, and demand 0.40 MJ(eq)/kWh of energy, resulting in an EPBT of approximately 1 year. The dry-cooled alternative is estimated to reduce LC water consumption by 77% but increase LC GHG emissions and CED by 8%. Synthetic nitrate salts may increase LC GHG emissions by 52% compared to mined. Switching from two-tank to thermocline TES configuration reduces LC GHG emissions, most significantly for plants using synthetically derived nitrate salts. CSP can significantly reduce GHG emissions compared to fossil-fueled generation; however, dry-cooling may be required in many locations to minimize water consumption.

Sensitivity of solar-cell performance to atmospheric variables. 2: Dissimilar cells at several locations

NASA Technical Reports Server (NTRS)

Klucher, T. M.; Hart, R. E.

1976-01-01

Several solar cells having dissimilar spectral response curves and cell construction were measured at various locations in the United States to determine sensitivity of cell performance to atmospheric water vapor and turbidity. The locations selected represent a broad range of summer atmospheric conditions, from clear and dry to turbid and humid. Cell short circuit current under direct normal incidence sunlight, the intensity, water vapor and turbidity were measured. Regression equations were developed from the limited data base in order to provide a single method of prediction of cell current sensitivity to the atmospheric variables.

Observing Seasonal and Diurnal Hydrometeorological Variability Within a Tropical Alpine Valley: Implications for Evapotranspiration

NASA Astrophysics Data System (ADS)

Hellstrom, R. A.; Mark, B. G.

2007-12-01

Conditions of glacier recession in the seasonally dry tropical Peruvian Andes motivate research to better constrain the hydrological balance in alpine valleys. There is an outstanding need to better understand the impact of the pronounced tropical hygric seasonality on energy and water budgets within pro-glacial valleys that channel glacier runoff to stream flow. This paper presents a novel embedded network installed in the glacierized Llanganuco valley of the Cordillera Blanca (9°S) comprising eight low-cost, discrete temperature and humidity microloggers ranging from 3470 to 4740 masl and an automatic weather station at 3850 masl. Data are aggregated into distinct dry and wet periods sampled from two full annual cycles (2004-2006) to explore patterns of diurnal and seasonal variability. The magnitude of diurnal solar radiation varies little within the valley between the dry and wet periods, while wet season near-surface air temperatures are cooler. Seasonally characteristic diurnal fluctuations in lapse rate partially regulate convection and humidity. Steep lapse rates during the wet season afternoon promote up-slope convection of warm, moist air and nocturnal rainfall events. Standardized grass reference evapotranspiration (ET0) was estimated using the FAO-56 algorithm of the United Nations Food and Agriculture Organization and compared with estimates of actual ET from the process-based BROOK90 model that incorporates more realistic vegetation parameters. Comparisons of composite diurnal cycles of ET for the wet and dry periods suggest about twice the daily ET0 during the dry period, attributed primarily to the 500% higher vapor pressure deficit and 20% higher daily total solar irradiance. Conversely, the near absence of rainfall during the dry season diminishes actual ET below that of the wet season by two orders of magnitude. Nearly cloud-free daylight conditions are critical for ET during the wet season. We found significant variability of ET with elevation up through the valley. Humidity and temperature measurements were analyzed to show significant effects of elevation and proximity to melt-water lakes on vapor pressure deficit.

[Seedling index of Salvia miltiorrhiza and its simulation model].

PubMed

Huang, Shu-Hua; Xu, Fu-Li; Wang, Wei-Ling; Du, Jun-Bo; Ru, Mei; Wang, Jing; Cao, Xian-Yan

2012-10-01

Through the correlation analysis on the quantitative traits and their ratios of Salvia miltiorrhiza seedlings and seedling quality, a series of representative indices reflecting the seedling quality of the plant species were determined, and the seedling index suitable to the S. miltiorrhiza seedlings was ascertained by correlation degree analysis. Meanwhile, based on the relationships between the seedling index and the air temperature, solar radiation and air humidity, a simulation model for the seedling index of S. miltiorrhiza was established. The experimental data of different test plots and planting dates were used to validate the model. The results showed that the root diameter, stem diameter, crown dry mass, root dry mass, and plant dry mass had significant positive relationships with the other traits, and could be used as the indicators of the seedling's health. The seedling index of S. miltiorrhiza could be calculated by (stem diameter/root diameter + root dry mass/crown dry mass) x plant dry mass. The stem diameter, root dry mass, crown dry mass and plant dry mass had higher correlations with the seedling index, and thus, the seedling index determined by these indicators could better reflect the seedling's quality. The coefficient of determination (R2) between the predicted and measured values based on 1:1 line was 0.95, and the root mean squared error (RMSE) was 0.15, indicating that the model established in this study could precisely reflect the quantitative relationships between the seedling index of S. miltiorrhiza and the environmental factors.

Performance analysis of solar-assisted chemical heat-pump dryer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fadhel, M.I.; Faculty of Engineering and Technology, Multimedia University, Jalan Ayer Keroh Lama, 75450, Melaka; Sopian, K.

2010-11-15

A solar-assisted chemical heat-pump dryer has been designed, fabricated and tested. The performance of the system has been studied under the meteorological conditions of Malaysia. The system consists of four main components: solar collector (evacuated tubes type), storage tank, solid-gas chemical heat pump unit and dryer chamber. A solid-gas chemical heat pump unit consists of reactor, condenser and evaporator. The reaction used in this study (CaCl2-NH{sub 3}). A simulation has been developed, and the predicted results are compared with those obtained from experiments. The maximum efficiency for evacuated tubes solar collector of 80% has been predicted against the maximum experimentmore » of 74%. The maximum values of solar fraction from the simulation and experiment are 0.795 and 0.713, respectively, whereas the coefficient of performance of chemical heat pump (COP{sup h}) maximum values 2.2 and 2 are obtained from simulation and experiments, respectively. The results show that any reduction of energy at condenser as a result of the decrease in solar radiation will decrease the coefficient of performance of chemical heat pump as well as decrease the efficiency of drying. (author)« less

Evaluation of two fiber optic-based solar collection and distribution systems for advanced space life support

NASA Technical Reports Server (NTRS)

Jack, D. A.; Nakamura, T.; Sadler, P.; Cuello, J. L.

2002-01-01

Growing plants in an enclosed controlled environment is crucial in developing bioregenerative life-support systems (BLSS) for space applications. The major challenge currently facing a BLSS is the extensive use of highly energy-intensive electric light sources, which leads to substantial energy wastes through heat dissipations by these lamps. An alternative lighting strategy is the use of a solar irradiance collection, transmission, and distribution system (SICTDS). Two types of fiber optic-based SICTDS, a Fresnel-lens Himawari and a parabolic-mirror optical waveguide (OW) lighting system, were evaluated. The overall efficiency for the OW SICTDS of 40.5% exceeded by 75% that for the Himawari of 23.2%. The spectral distributions of the light delivered by the Himawari and the OW SICTDS were almost identical and had practically no difference from that of terrestrial solar radiation. The ratios of photosynthetically active radiation (PAR) to total emitted radiation (k) of 0.39 +/- 0.02 for the Himawari and 0.41 +/- 0.04 for the OW SICTDS were statistically indistinguishable, were not significantly different from that of 0.042 +/- 0.01 for terrestrial solar radiation, and were comparable to that of 0.35 for a high-pressure sodium (HPS) lamp. The coefficients of variation (CV) of 0.34 and 0.39 for PPF distributions, both at 50 mm X 50 mm square grid arrays, corresponding to the Himawari and the OW SICTDS, respectively, were comparable with each other but were both significantly greater than the CV of 0.08 corresponding to the HPS lamp. The average fresh weight or dry weight of lettuce grown in the solar chamber with either the Himawari or the OW SICTDS showed no statistical difference from the average fresh weight or dry weight of lettuce grown in the reference chamber with the HPS lamp. The results of this study suggest that an SICTDS could help reduce the electric power demand in a BLSS.

Generating daily weather data for ecosystem modelling in the Congo River Basin

NASA Astrophysics Data System (ADS)

Petritsch, Richard; Pietsch, Stephan A.

2010-05-01

Daily weather data are an important constraint for diverse applications in ecosystem research. In particular, temperature and precipitation are the main drivers for forest ecosystem productivity. Mechanistic modelling theory heavily relies on daily values for minimum and maximum temperatures, precipitation, incident solar radiation and vapour pressure deficit. Although the number of climate measurement stations increased during the last centuries, there are still regions with limited climate data. For example, in the WMO database there are only 16 stations located in Gabon with daily weather measurements. Additionally, the available time series are heavily affected by measurement errors or missing values. In the WMO record for Gabon, on average every second day is missing. Monthly means are more robust and may be estimated over larger areas. Therefore, a good alternative is to interpolate monthly mean values using a sparse network of measurement stations, and based on these monthly data generate daily weather data with defined characteristics. The weather generator MarkSim was developed to produce climatological time series for crop modelling in the tropics. It provides daily values for maximum and minimum temperature, precipitation and solar radiation. The monthly means can either be derived from the internal climate surfaces or prescribed as additional inputs. We compared the generated outputs observations from three climate stations in Gabon (Lastourville, Moanda and Mouilla) and found that maximum temperature and solar radiation were heavily overestimated during the long dry season. This is due to the internal dependency of the solar radiation estimates to precipitation. With no precipitation a cloudless sky is assumed and thus high incident solar radiation and a large diurnal temperature range. However, in reality it is cloudy in the Congo River Basin during the long dry season. Therefore, we applied a correction factor to solar radiation and temperature range based on the ratio of values on rainy days and days without rain, respectively. For assessing the impact of our correction, we simulated the ecosystem behaviour using the climate data from Lastourville, Moanda and Mouilla with the mechanistic ecosystem model Biome-BGC. Differences in terms of the carbon, nitrogen and water cycle were subsequently analysed and discussed.

Artificial twin-layer configurations of Zn(O,S) films by radio frequency sputtering in all dry processed eco-friendly Cu(In,Ga)Se2 solar cells

NASA Astrophysics Data System (ADS)

Liu, Wei; Fan, Yu; Li, Xiaodong; Lin, Shuping; Liu, Yang; Shi, Sihan; Wang, He; Zhou, Zhiqiang; Zhang, Yi; Sun, Yun

2018-03-01

Cu(In,Ga)Se2 thin film solar cells are of great interest for research and industrial applications with their high conversion efficiencies, long-term stability and significant lifetimes. Such a solar cell of a p-n junction consists of p-type Cu(In,Ga)Se2 films as a light absorber and n-type CdS as a buffer layer, which often emerges with intrinsic ZnO. Aimed at eco-friendly fabrication protocols, a large number of strategies have been investigated to fabricate a Cd-free n-type buffer layer such as Zn(O,S) in Cu(In,Ga)Se2 solar cells. Also, if the Zn(O,S) films are prepared by coevaporation or sputtering, it will offer high compatibility with the preferred mass production. Here, we propose and optimize a dry method for Zn(O,S) deposition in a radio frequency sputtering. In particular, the strategy for the twin-layer configurations of Zn(O,S) films not only greatly improve their electrical conductance and suppress charge carrier recombination, but also avoid degradation of the Zn(O,S)/Cu(In,Ga)Se2 interfaces. Indeed, the high quality of such twin Zn(O,S) layers have been reflected in the similar conversion efficiencies of the complete solar cells as well as the large short-circuit current density, which exceeds the CdS reference device. In addition, Zn(O,S) twin layers have reduced the production time and materials by replacing the CdS/i-ZnO layers, which removes two fabrication steps in the multilayered thin film solar cells. Furthermore, the device physics for such improvements have been fully unveiled with both experimental current-voltage and capacitance-voltage spectroscopies and device simulations via wxAMPS program. Finally, the proposed twin-layer Zn(O,S)/Cu(In,Ga)Se2 interfaces account for the broadening of the depletion region of photogenerated charge carriers, which greatly suppress the carrier recombination at the space charge region, and eventually lead to the more efficient collection of charge carriers at both electrodes.

Development and testing of thermal energy storage modules for use in active solar heating and cooling systems

NASA Technical Reports Server (NTRS)

Parker, J. C.

1981-01-01

The project development requirements and criteria are presented along with technical data for the modules. Performance tests included: ducting, temperature, pressure and air flow measurements, dry and wet bulb temperature; duct pressure measurements; and air conditioning apparatus checks; installation, operation, and maintenance instructions are included.

Climatic data for Williams Lake, Hubbard County, Minnesota, 1983

USGS Publications Warehouse

Sturrock, A.M.; Rosenberry, D.O.; Engelbrecht, L.G.; Gothard, W.A.; Winter, T.C.

1984-01-01

Research on the hydrology of Williams Lake, north-central Minnesota includes study of evaporation. Presented here are those climatic data needed for energy-budget and mass-transfer studies,including: water-surface temperature, dry-bulb and wet-bulb air temperatures, wind speed, precipitation, and solar radiation. Data are collected at raft and land stations.

Stratospheric and solar cycle effects on long-term variability of mesospheric ice clouds

NASA Astrophysics Data System (ADS)

Lübken, F.-J.; Berger, U.; Baumgarten, G.

2009-11-01

Model results of mesospheric ice layers and background conditions at 69°N from 1961 to 2008 are analyzed. The model nudges to European Centre for Medium-Range Weather Forecasts data below ˜45 km. Greenhouse gas concentrations in the mesosphere are kept constant. At polar mesospheric cloud (PMC) altitudes (83 km) temperatures decrease until the mid 1990s by -0.08 K/yr resulting in trends of PMC brightness, occurrence rates, and, to a lesser extent, in PMC altitudes (-0.0166 km/yr). Ice layer trends are consistent with observations by ground-based and satellite instruments. Water vapor increases at PMC heights and decreases above due to increased freeze-drying caused by the temperature trend. Temperature trends in the mesosphere mainly come from shrinking of the stratosphere and from dynamical effects. A solar cycle modulation of H2O is observed in the model consistent with satellite observations. The effect on ice layers is reduced because of redistribution of H2O by freeze-drying. The accidental coincidence of low temperatures and solar cycle minimum in the mid 1990s leads to an overestimation of solar effects on ice layers. A strong correlation between temperatures and PMC altitudes is observed. Applied to historical measurements this gives negligible temperature trends at PMC altitudes (˜0.01-0.02 K/yr). Strong correlations between PMC parameters and background conditions deduced from the model confirm the standard scenario of PMC formation. The PMC sensitivity on temperatures, water vapor, and Ly-α is investigated. PMC heights show little variation with background parameters whereas brightness and occurrence rates show large variations. None of the background parameters can be ignored regarding its influence on ice layers.

Stratospheric and solar cycle effects on long-term variability of mesospheric ice clouds

NASA Astrophysics Data System (ADS)

Lübken, F.-J.; Berger, U.; Baumgarten, G.

2009-01-01

Model results of mesospheric ice layers and background conditions at 69°N from 1961 to 2008 are analyzed. The model nudges to European Centre for Medium-Range Weather Forecasts data below ˜45 km. Greenhouse gas concentrations in the mesosphere are kept constant. At polar mesospheric cloud (PMC) altitudes (83 km) temperatures decrease until the mid 1990s by -0.08 K/yr resulting in trends of PMC brightness, occurrence rates, and, to a lesser extent, in PMC altitudes (-0.0166 km/yr). Ice layer trends are consistent with observations by ground-based and satellite instruments. Water vapor increases at PMC heights and decreases above due to increased freeze-drying caused by the temperature trend. Temperature trends in the mesosphere mainly come from shrinking of the stratosphere and from dynamical effects. A solar cycle modulation of H2O is observed in the model consistent with satellite observations. The effect on ice layers is reduced because of redistribution of H2O by freeze-drying. The accidental coincidence of low temperatures and solar cycle minimum in the mid 1990s leads to an overestimation of solar effects on ice layers. A strong correlation between temperatures and PMC altitudes is observed. Applied to historical measurements this gives negligible temperature trends at PMC altitudes (˜0.01-0.02 K/yr). Strong correlations between PMC parameters and background conditions deduced from the model confirm the standard scenario of PMC formation. The PMC sensitivity on temperatures, water vapor, and Ly-α is investigated. PMC heights show little variation with background parameters whereas brightness and occurrence rates show large variations. None of the background parameters can be ignored regarding its influence on ice layers.

Investigating chaotic features in solar radiation over a tropical station using recurrence quantification analysis

NASA Astrophysics Data System (ADS)

Ogunjo, Samuel T.; Adediji, Adekunle T.; Dada, Joseph B.

2017-01-01

The use of solar energy for power generation and other uses is on the increase. This demand necessitate a better understanding of the underlying dynamics for better prediction. Nonlinear dynamics and its associated tools readily lend itself for such analysis. In this paper, nonlinearity in solar radiation data is tested using recurrence plot (RP) and recurrence quantification analysis (RQA) in a tropical station. The data used was obtained from an ongoing campaign at the Federal University of Technology, Akure, Southwestern Nigeria using an Integrated Sensor Suite (Vantage2 Pro). Half hourly and daily values were tested for each month of the year. Both were found to be nonlinear. The dry months of the year exhibit higher chaoticity compared to the wet months of the year. The daily average values were found to be mildly chaotic. Using RQA, features due to external effects such as harmattan and intertropical discontinuity (ITD) on solar radiation data were uniquely identified.

Solar Insolation Effect on the Local Distribution of Lunar Hydroxyl

NASA Astrophysics Data System (ADS)

Kim, Suyeon; Yi, Yu; Hong, Ik-Seon; Sohn, Jongdae

2018-03-01

Moon mineralogy mapper (M3)'s work proved that the moon is not completely dry but has some hydroxyl/water. M3's data confirmed that the amount of hydroxyl on the lunar surface is inversely related to the measured signal brightness, suggesting the lunar surface is sensitive to temperature by solar insolation. We tested the effect of solar insolation on the local distribution of hydroxyl by using M3 data, and we found that most craters had more hydroxyl in shade areas than in sunlit areas. This means that the local distribution of hydroxyl is absolutely influenced by the amount of sunshine. We investigated the factors affecting differences in hydroxyl; we found that the higher the latitude, the larger the difference during daytime. We also measured the pyroxene content and found that pyroxene affects the amount of hydroxyl, but it does not affect the difference in hydroxyl between sunlit and shaded areas. Therefore, we confirmed that solar insolation plays a significant role in the local distribution of hydroxyl, regardless of surface composition.

Microbial ecology of extreme environments: Antarctic yeasts and growth in substrate-limited habitats

NASA Technical Reports Server (NTRS)

Vishniac, H. S.

1985-01-01

The high, dry valleys of the Ross Desert of Antarctic, characterized by extremely low temperatures, aridity and a depauperate biota, are used as an analog of the postulated extreme climates of other planetary bodies of the Solar System to test the hypothesis that if life could be supported by Ross, it might be possible where similar conditions prevail. The previously considered sterility of the Ross Desert soil ecosystem has yielded up an indigenous yeast, Cryptoccus vishniacci, which is able to resist the extremes of cold, wet and dry freezing, and long arid periods, while making minimal nutritional demands on the soil.

Solar-powered drip irrigation enhances food security in the Sudano–Sahel

PubMed Central

Burney, Jennifer; Woltering, Lennart; Burke, Marshall; Naylor, Rosamond; Pasternak, Dov

2010-01-01

Meeting the food needs of Africa’s growing population over the next half-century will require technologies that significantly improve rural livelihoods at minimal environmental cost. These technologies will likely be distinct from those of the Green Revolution, which had relatively little impact in sub-Saharan Africa; consequently, few such interventions have been rigorously evaluated. This paper analyzes solar-powered drip irrigation as a strategy for enhancing food security in the rural Sudano–Sahel region of West Africa. Using a matched-pair comparison of villages in northern Benin (two treatment villages, two comparison villages), and household survey and field-level data through the first year of harvest in those villages, we find that solar-powered drip irrigation significantly augments both household income and nutritional intake, particularly during the dry season, and is cost effective compared to alternative technologies. PMID:20080616

Collaborative observations of the Sun during ihy

NASA Astrophysics Data System (ADS)

Strong, K. T.

2003-04-01

Many of the major solar physics space missions (Solar Max, Yohkoh, SOHO, and TRACE) have feature extensive collaborative observations with ground-based observers, sounding rocket flights and other space missions. These joint observations have produced some significant results. In preparation for IHY, this poster presents some of the lessons learned from some of these collaborations. The more successful ones have a clear scientific goal and have been planned, coordinated and advertised well in advance with at least one dry run. They have generally not relied on a particular type of solar activity being present at the time of the observations or have been very flexible in the timing of the investigation. Most importantly, they have had a plan with a set schedule to follow up the observation run with data processing, analysis and modeling workshops whether it's a large group or just individual scientists.

Phthalimide Copolymer Solar Cells

NASA Astrophysics Data System (ADS)

Xin, Hao; Guo, Xugang; Ren, Guoqiang; Kim, Felix; Watson, Mark; Jenekhe, Samson

2010-03-01

Photovoltaic properties of bulk heterojunction solar cells based on phthalimide donor-acceptor copolymers have been investigated. Due to the strong π-π stacking of the polymers, the state-of-the-art thermal annealing approach resulted in micro-scale phase separation and thus negligible photocurrent. To achieve ideal bicontinuous morphology, different strategies including quickly film drying and mixed solvent for film processing have been explored. In these films, nano-sale phase separation was achieved and a power conversion efficiency of 3.0% was obtained. Absorption and space-charge limited current mobility measurements reveal similar light harvesting and hole mobilities in all the films, indicating that the morphology is the dominant factor determining the photovoltaic performance. Our results demonstrate that for highly crystalline and/or low-solubility polymers, finding a way to prevent polymer aggregation and large scale phase separation is critical to realizing high performance solar cells.

Round-Trip Solar Electric Propulsion Missions for Mars Sample Return

NASA Technical Reports Server (NTRS)

Bailey, Zachary J.; Sturm, Erick J.; Kowalkowski, Theresa D.; Lock, Robert E.; Woolley, Ryan C.; Nicholas, Austin K.

2014-01-01

Mars Sample Return (MSR) missions could benefit from the high specific impulse of Solar Electric Propulsion (SEP) to achieve lower launch masses than with chemical propulsion. SEP presents formulation challenges due to the coupled nature of launch vehicle performance, propulsion system, power system, and mission timeline. This paper describes a SEP orbiter-sizing tool, which models spacecraft mass & timeline in conjunction with low thrust round-trip Earth-Mars trajectories, and presents selected concept designs. A variety of system designs are possible for SEP MSR orbiters, with large dry mass allocations, similar round-trip durations to chemical orbiters, and reduced design variability between opportunities.

Performance analysis of an air drier for a liquid dehumidifier solar air conditioning system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Queiroz, A.G.; Orlando, A.F.; Saboya, F.E.M.

1988-05-01

A model was developed for calculating the operating conditions of a non-adiabatic liquid dehumidifier used in solar air conditioning systems. In the experimental facility used for obtaining the data, air and triethylene glycol circulate countercurrently outside staggered copper tubes which are the filling of an absorption tower. Water flows inside the copper tubes, thus cooling the whole system and increasing the mass transfer potential for drying air. The methodology for calculating the mass transfer coefficient is based on the Merkel integral approach, taking into account the lowering of the water vapor pressure in equilibrium with the water glycol solution.

Solar Living House Final Technical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walters, Bradley

The Solar Living House is a high-performance solar-powered dwelling designed by a team of faculty and students from the University of Florida, in collaboration with Santa Fe College, the National University of Singapore, and Alachua Habitat for Humanity. The project was designed in accordance with the Solar Decathlon 2015, a research, design, education, and outreach program developed by the U.S. Department of Energy (DOE). The Solar Living House is fundamentally a house for living, centered on people and the activities of daily life while quietly introducing advanced design, construction, and engineering technologies. The 993 square-foot two-bedroom one-bath home was designedmore » to embrace and frame an exterior courtyard space. This courtyard acts as an extension of the interior living spaces, maximizing the spatial potentials of a modest building footprint and introducing natural light into the primary living spaces of the house. Research Outcomes: The Solar Living House advances work on high-performance buildings through three principal technological innovations: wet/dry modular construction, a building automation system, and solar dehumidification systems. Wet / Dry Modular Construction: The house is designed as a series of five modules, including one that is designated as the “wet core.” The wet core consolidates the mechanical systems and bathroom into a single module to reduce plumbing runs, efficiency losses, and on-site construction time. The other four modules are designed to eliminate interior load bearing walls to allow for maximum flexibility in the reconfiguring of the space over time. The modules are designed to meet the structural challenges of both Florida’s hurricanes and California’s earthquakes. Building Automation System: The house is equipped with an integrated building automation system, allowing the houses environmental systems, lights, security systems, and smoke detectors to be programmed, monitored, and controlled through any mobile or computing device. These systems allow for more precise calibrations of temperature/humidity/lighting to correspond with user needs and preferences, minimizing energy losses with economical night- or day-time setbacks. Solar Dehumidification System: The most significant technological innovation in the Solar Living House is the solar thermal dehumidification system. This system generates hot water through two rooftop-mounted evacuated tube solar thermal collectors. The hot water is used to continually dry a regenerative solid desiccant material, typically white silica gel. The solid desiccant is used to adsorb moisture and humidity from the air without additional mechanical cooling. This strategy allows humidity to be modulated independently of air temperature, providing greater thermal comfort and reducing the opportunity for the growth of mold spores within the house while also reducing the overall energy consumption of the HVAC system. Economic Feasibility: The team set aggressive goals for affordability, targeting a construction cost of $138,710. An independent professional cost estimator determined the overall project costs, as designed, would be $333,799, or $336.15 per square foot of finished floor area. This is more than 2.4 times the target construction cost. By comparison, the average construction cost for a home in the United States in 2015 was $289,415, or $103.29 per square foot of finished floor area. Following work on the Solar Living House, team leaders incorporated many of its objectives into a net-zero energy home on a site in Gainesville, Florida. This site-built home avoided many of the constraints and complications of modular construction necessitated by the Solar Decathlon, allowing it to be built for a much more modest budget. This two-bedroom two bath 1,800 square foot home was constructed for $135.39 per square foot, including active photovoltaic solar systems, careful attention to continuous air barriers, increased insulation levels, and permanent site constructions. This project suggest that high-performance buildings can be realized for more modest budgets. Public Benefits: Work on the Solar Living House and Solar Decathlon 2015 offered our student team unparalleled learning opportunities. Because of the duration of the project, a number of students participated at different points in their education, from first year undergraduates all the way through to advanced graduate students. The opportunity for collaboration with students and faculty from the National University of Singapore was also extraordinary, allowing for a sharing of technical knowledge and cultural exchange. The wider public has benefited from this work as its findings have been shared through public presentations and publications. It serves as a useful stepping stone along the path towards affordable, high-performance buildings.« less

Climatic data for Williams Lake, Hubbard County, Minnesota, 1984

USGS Publications Warehouse

Sturrock, A.M.; Rosenberry, D.O.; Scarborough, J.L.; Winter, T.C.

1986-01-01

Research on the hydrology of Williams Lake, north-central Minnesota includes study of evaporation. Presented here are those climatic data needed for energy-budget and mass-transfer studies, including: water-surface temperature, dry-bulb and wet-bulb air temperatures, wind speed, precipitation, and solar and atmospheric radiation. Data are collected at raft and land stations.

Climatic data for Williams Lake, Hubbard County, Minnesota, 1985

USGS Publications Warehouse

Sturrock, A.M.; Rosenberry, D.O.; Winter, T.C.

1987-01-01

Research on the hydrology of Williams Lake, north-central Minnesota includes study of evaporation. Presented here are those climatic data needed for energy-budget and mass-transfer studies, including: water-surface temperature, dry-bulb and wet-bulb air temperatures, wind speed, precipitation, and solar and atmospheric radiation. Data are collected at raft and land stations.

Controlled Deposition and Performance Optimization of Perovskite Solar Cells Using Ultrasonic Spray-Coating of Photoactive Layers.

PubMed

Chang, Wei-Chieh; Lan, Ding-Hung; Lee, Kun-Mu; Wang, Xiao-Feng; Liu, Cheng-Liang

2017-04-10

This study investigated a new film-deposition technique, ultrasonic spray-coating, for use in the production of a photoactive layer of perovskite solar cells. Stable atomization and facile fabrication of perovskite thin films by ultrasonic spray-coating were achieved in a one-step method through manipulating the ink formulation (e.g., solution concentration, precursor composition, and mixing solvent ratio) and the drying kinetics (e.g., post-annealing temperature). The performance of the perovskite solar cells was mainly influenced by the intrinsic film morphology and crystalline orientation of the deposited perovskite layer. By suitable optimization of the spreading and drying conditions of the ink, ultrasonic spray-coated perovskite photovoltaic devices were obtained with a maximum power conversion efficiency of 11.30 %, a fill factor of 73.6 %, a short-circuit current of 19.7 mA cm -1 , and an open-circuit voltage of 0.78 V, respectively. Notably, the average power efficiency reached above 10 %, attributed to the large flower-like perovskite crystal with orientation along the (1 1 2)/(2 0 0) and (2 2 4)/(4 0 0) directions. Thus, the ultrasonic spray-coating method for perovskite photoactive layers, combining advantages of good photovoltaic performance results and benefits from cost and processing, has the potential for large-scale commercial production. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Solar Reforming of Carbon Dioxide to Produce Diesel Fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dennis Schuetzle; Robert Schuetzle

2010-12-31

This project focused on the demonstration of an innovative technology, referred to as the Sunexus CO2 Solar Reformer, which utilizes waste CO2 as a feedstock for the efficient and economical production of synthetic diesel fuel using solar thermal energy as the primary energy input. The Sunexus technology employs a two stage process for the conversion of CO2 to diesel fuel. A solar reforming system, including a specially designed reactor and proprietary CO2 reforming catalyst, was developed and used to convert captured CO2 rich gas streams into syngas (primarily hydrogen and carbon monoxide) using concentrated solar energy at high conversion efficiencies.more » The second stage of the system (which has been demonstrated under other funding) involves the direct conversion of the syngas into synthetic diesel fuel using a proprietary catalyst (Terra) previously developed and validated by Pacific Renewable Fuels and Chemicals (PRFC). The overall system energy efficiency for conversion of CO2 to diesel fuel is 74%, due to the use of solar energy. The results herein describe modeling, design, construction, and testing of the Sunexus CO2 Solar Reformer. Extensive parametric testing of the solar reformer and candidate catalysts was conducted and chemical kinetic models were developed. Laboratory testing of the Solar Reformer was successfully completed using various gas mixtures, temperatures, and gas flow rates/space velocities to establish performance metrics which can be employed for the design of commercial plants. A variety of laboratory tests were conducted including dry reforming (CO2 and CH{sub 4}), combination dry/steam reforming (CO2, CH{sub 4} & H{sub 2}O), and tri-reforming (CO2, CH{sub 4}, H{sub 2}O & O{sub 2}). CH{sub 4} and CO2 conversions averaged 95-100% and 50-90% per reformer cycle, respectively, depending upon the temperatures and gas space velocities. No formation of carbon deposits (coking) on the catalyst was observed in any of these tests. A 16 ft. diameter, concentrating solar dish was modified to accommodate the Sunexus CO2 Solar Reformer and the integrated system was installed at the Pacific Renewable Fuels and Chemicals test site at McClellan, CA. Several test runs were conducted without catalyst during which the ceramic heat exchanger in the Sunexus Solar Reformer reached temperatures between 1,050 F (566 C) and 2,200 F (1,204 C) during the test period. A dry reforming mixture of CO2/CH{sub 4} (2.0/1.0 molar ratio) was chosen for all of the tests on the integrated solar dish/catalytic reformer during December 2010. Initial tests were carried out to determine heat transfer from the collimated solar beam to the catalytic reactor. The catalyst was operated successfully at a steady-state temperature of 1,125 F (607 C), which was sufficient to convert 35% of the 2/1 CO2/CH{sub 4} mixture to syngas. This conversion efficiency confirmed the results from laboratory testing of this catalyst which provided comparable syngas production efficiencies (40% at 1,200 F [650 C]) with a resulting syngas composition of 20% CO, 16% H{sub 2}, 39% CO2 and 25% CH{sub 4}. As based upon the laboratory results, it is predicted that 90% of the CO2 will be converted to syngas in the solar reformer at 1,440 F (782 C) resulting in a syngas composition of 50% CO: 43% H{sub 2}: 7% CO2: 0% CH{sub 4}. Laboratory tests show that the higher catalyst operating temperature of 1,440 F (782 C) for efficient conversion of CO2 can certainly be achieved by optimizing solar reactor heat transfer, which would result in the projected 90% CO2-to-syngas conversion efficiencies. Further testing will be carried out during 2011, through other funding support, to further optimize the solar dish CO2 reformer. Additional studies carried out in support of this project and described in this report include: (1) An Assessment of Potential Contaminants in Captured CO2 from Various Industrial Processes and Their Possible Effect on Sunexus CO2 Reforming Catalysts; (2) Recommended Measurement Methods for Assessing Contaminant Levels in Captured CO2 Streams; (3) An Assessment of Current Commercial Scale Fisher-Tropsch (F-T) Technologies for the Conversion of Syngas to Fuels; (4) An Overview of CO2 Capture Technologies from Various Industrial Sources; and (5) Lifecycle Analysis for the Capture and Conversion of CO2 to Synthetic Diesel Fuel. Commercial scale Sunexus CO2 Solar Reformer plant designs, proposed in this report, should be able to utilize waste CO2 from a wide variety of industrial sources to produce a directly usable synthetic diesel fuel that replaces petroleum derived fuel, thus improving the United States energy security while also sequestering CO2. Our material balance model shows that every 5.0 lbs of CO2 is transformed using solar energy into 6.26 lbs (1.0 U.S. gallon) of diesel fuel and into by-products, which includes water. Details are provided in the mass and energy model in this report.« less

Regional Climate Variability Under Model Simulations of Solar Geoengineering

NASA Astrophysics Data System (ADS)

Dagon, Katherine; Schrag, Daniel P.

2017-11-01

Solar geoengineering has been shown in modeling studies to successfully mitigate global mean surface temperature changes from greenhouse warming. Changes in land surface hydrology are complicated by the direct effect of carbon dioxide (CO2) on vegetation, which alters the flux of water from the land surface to the atmosphere. Here we investigate changes in boreal summer climate variability under solar geoengineering using multiple ensembles of model simulations. We find that spatially uniform solar geoengineering creates a strong meridional gradient in the Northern Hemisphere temperature response, with less consistent patterns in precipitation, evapotranspiration, and soil moisture. Using regional summertime temperature and precipitation results across 31-member ensembles, we show a decrease in the frequency of heat waves and consecutive dry days under solar geoengineering relative to a high-CO2 world. However in some regions solar geoengineering of this amount does not completely reduce summer heat extremes relative to present day climate. In western Russia and Siberia, an increase in heat waves is connected to a decrease in surface soil moisture that favors persistent high temperatures. Heat waves decrease in the central United States and the Sahel, while the hydrologic response increases terrestrial water storage. Regional changes in soil moisture exhibit trends over time as the model adjusts to solar geoengineering, particularly in Siberia and the Sahel, leading to robust shifts in climate variance. These results suggest potential benefits and complications of large-scale uniform climate intervention schemes.

Silicon Nanowires for Solar Thermal Energy Harvesting: an Experimental Evaluation on the Trade-off Effects of the Spectral Optical Properties.

PubMed

Sekone, Abdoul Karim; Chen, Yu-Bin; Lu, Ming-Chang; Chen, Wen-Kai; Liu, Chia-An; Lee, Ming-Tsang

2016-12-01

Silicon nanowire possesses great potential as the material for renewable energy harvesting and conversion. The significantly reduced spectral reflectivity of silicon nanowire to visible light makes it even more attractive in solar energy applications. However, the benefit of its use for solar thermal energy harvesting remains to be investigated and has so far not been clearly reported. The purpose of this study is to provide practical information and insight into the performance of silicon nanowires in solar thermal energy conversion systems. Spectral hemispherical reflectivity and transmissivity of the black silicon nanowire array on silicon wafer substrate were measured. It was observed that the reflectivity is lower in the visible range but higher in the infrared range compared to the plain silicon wafer. A drying experiment and a theoretical calculation were carried out to directly evaluate the effects of the trade-off between scattering properties at different wavelengths. It is clearly seen that silicon nanowires can improve the solar thermal energy harnessing. The results showed that a 17.8 % increase in the harvest and utilization of solar thermal energy could be achieved using a silicon nanowire array on silicon substrate as compared to that obtained with a plain silicon wafer.

Dry-Deposited Transparent Carbon Nanotube Film as Front Electrode in Colloidal Quantum Dot Solar Cells.

PubMed

Zhang, Xiaoliang; Aitola, Kerttu; Hägglund, Carl; Kaskela, Antti; Johansson, Malin B; Sveinbjörnsson, Kári; Kauppinen, Esko I; Johansson, Erik M J

2017-01-20

Single-walled carbon nanotubes (SWCNTs) show great potential as an alternative material for front electrodes in photovoltaic applications, especially for flexible devices. In this work, a press-transferred transparent SWCNT film was utilized as front electrode for colloidal quantum dot solar cells (CQDSCs). The solar cells were fabricated on both glass and flexible substrates, and maximum power conversion efficiencies of 5.5 and 5.6 %, respectively, were achieved, which corresponds to 90 and 92 % of an indium-doped tin oxide (ITO)-based device (6.1 %). The SWCNTs are therefore a very good alternative to the ITO-based electrodes especially for flexible solar cells. The optical electric field distribution and optical losses within the devices were simulated theoretically and the results agree with the experimental results. With the optical simulations that were performed it may also be possible to enhance the photovoltaic performance of SWCNT-based solar cells even further by optimizing the device configuration or by using additional optical active layers, thus reducing light reflection of the device and increasing light absorption in the quantum dot layer. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Air emissions due to wind and solar power.

PubMed

Katzenstein, Warren; Apt, Jay

2009-01-15

Renewables portfolio standards (RPS) encourage large-scale deployment of wind and solar electric power. Their power output varies rapidly, even when several sites are added together. In many locations, natural gas generators are the lowest cost resource available to compensate for this variability, and must ramp up and down quickly to keep the grid stable, affecting their emissions of NOx and CO2. We model a wind or solar photovoltaic plus gas system using measured 1-min time-resolved emissions and heat rate data from two types of natural gas generators, and power data from four wind plants and one solar plant. Over a wide range of renewable penetration, we find CO2 emissions achieve approximately 80% of the emissions reductions expected if the power fluctuations caused no additional emissions. Using steam injection, gas generators achieve only 30-50% of expected NOx emissions reductions, and with dry control NOx emissions increase substantially. We quantify the interaction between state RPSs and NOx constraints, finding that states with substantial RPSs could see significant upward pressure on NOx permit prices, if the gas turbines we modeled are representative of the plants used to mitigate wind and solar power variability.

Bidirectional measurements of surface reflectance for view angle corrections of oblique imagery

NASA Technical Reports Server (NTRS)

Jackson, R. D.; Teillet, P. M.; Slater, P. N.; Fedosejevs, G.; Jasinski, Michael F.

1990-01-01

An apparatus for acquiring bidirectional reflectance-factor data was constructed and used over four surface types. Data sets were obtained over a headed wheat canopy, bare soil having several different roughness conditions, playa (dry lake bed), and gypsum sand. Results are presented in terms of relative bidirectional reflectance factors (BRFs) as a function of view angle at a number of solar zenith angles, nadir BRFs as a function of solar zenith angles, and, for wheat, vegetation indices as related to view and solar zenith angles. The wheat canopy exhibited the largest BRF changes with view angle. BRFs for the red and the NIR bands measured over wheat did not have the same relationship with view angle. NIR/Red ratios calculated from nadir BRFs changed by nearly a factor of 2 when the solar zenith angle changed from 20 to 50 degs. BRF versus view angle relationships were similar for soils having smooth and intermediate rough surfaces but were considerably different for the roughest surface. Nadir BRF versus solar-zenith angle relationships were distinctly different for the three soil roughness levels. Of the various surfaces, BRFs for gypsum sand changed the least with view angle (10 percent at 30 degs).

Water flow and energy balance for a tropical dry semideciduous forest

NASA Astrophysics Data System (ADS)

Andrade, J. L.; Garruña-Hernandez, R.; Leon-Palomo, M.; Us-Santamaria, R.; Sima, J. L.

2013-05-01

Tropical forests cool down locally because increase water evaporation from the soil to the atmosphere, reduce albedo and help forming clouds that reflect solar radiation back to the atmosphere; this, aligned to the carbon catchment, increase forests value. We will present an estimation of the sap flow and energy balance for the tropical dry semideciduous forest at Kiuic, Yucatan, Mexico during a year. We use a meteorological tower equipped with a rain gauge, temperature and relative humidity, heat flow plates, thermocouples and volumetric soil water content. We recorded net radiation and soil heat flux and estimated sensible heat and latent heat. Besides, we estimated latent heat by measuring sap flow directly in tres using disispation constant heat probes during the rainy season. Results show the influence of the seasonality on net radiation, air temperatura and vapor pressure deficit, because during the dry season his variables were higher and with more duation than during the rainy and early dry season. Sap flow was different for trees belonging to the family Fabaceae compared to trees from other families.

Selected meteorological data for an arid climate over bare soil near Beatty, Nye County, Nevada, November 1977 through May 1980

USGS Publications Warehouse

Brown, Robin G.; Nichols, William D.

1990-01-01

Meteorological data were collected over bare soil at a site for low-level radioactive-waste burial near Beatty, Nevada, from November 1977 to May 1980. The data include precipitation, windspeed, wind direction, incident solar radiation, reflected solar radiation, net radiation, dry- and wet-bulb air temperatures at three heights, soil temperature at five depths, and soil-heat flux at three depths. Mean relative humidity was computed for each day of the collection period for which data are available.A discussion is presented of the study site and the instrumentation and procedures used for collecting and processing the data. Selected data from November 1977 to May 1980 are presented in tabular form. Diurnal fluctuations of selected meteorological variables for representative summer and winter periods are graphically presented. The effects on selected variables of a partial solar eclipse are also discussed

Photodegradation at day, microbial decomposition at night - decomposition in arid lands

NASA Astrophysics Data System (ADS)

Gliksman, Daniel; Gruenzweig, Jose

2014-05-01

Our current knowledge of decomposition in dry seasons and its role in carbon turnover is fragmentary. So far, decomposition during dry seasons was mostly attributed to abiotic mechanisms, mainly photochemical and thermal degradation, while the contribution of microorganisms to the decay process was excluded. We asked whether microbial decomposition occurs during the dry season and explored its interaction with photochemical degradation under Mediterranean climate. We conducted a litter bag experiment with local plant litter and manipulated litter exposure to radiation using radiation filters. We found notable rates of CO2 fluxes from litter which were related to microbial activity mainly during night-time throughout the dry season. This activity was correlated with litter moisture content and high levels of air humidity and dew. Day-time CO2 fluxes were related to solar radiation, and radiation manipulation suggested photodegradation as the underlying mechanism. In addition, a decline in microbial activity was followed by a reduction in photodegradation-related CO2 fluxes. The levels of microbial decomposition and photodegradation in the dry season were likely the factors influencing carbon mineralization during the subsequent wet season. This study showed that microbial decomposition can be a dominant contributor to CO2 emissions and mass loss in the dry season and it suggests a regulating effect of microbial activity on photodegradation. Microbial decomposition is an important contributor to the dry season decomposition and impacts the annual litter turn-over rates in dry regions. Global warming may lead to reduced moisture availability and dew deposition, which may greatly influence not only microbial decomposition of plant litter, but also photodegradation.

Structural variability and species diversity of a dwarf Caribbean dry forest

Treesearch

E. Medina; E. Cuevas; S. Molina; A.E. Lugo; O. Ramos

2010-01-01

Low stature woody vegetation of the south-west coast of Puerto Rico grows on a rocky calcareous substrate where plants can only root in holes, cracks, and crevices accumulating water and sediments that allow seed germination and seedling development. Being in a coastal location these communities are influenced by steady onshore winds, high solar radiation, and salt...

Foliar uptake of fog in the coast redwood ecosystem: a novel drought-alleviation strategy shared by most redwood forest plants

Treesearch

Emily Limm; Kevin Simonin; Tod Dawson

2012-01-01

Fog inundates the coast redwood forests of northern California frequently during the summer months (May to September) when rainfall is largely absent (Azevedo and Morgan 1974, Byers 1953, Oberlander 1956). This maritime fog modifies otherwise warm and dry summer climate by increasing humidity, decreasing the air temperature, reducing solar radiation, and...

Climatic data for Mirror Lake, West Thornton, New Hampshire, 1981-82

USGS Publications Warehouse

Sturrock, A.M.; Buso, D.C.; Bieber, G.M.; Engelbrecht, L.G.; Winter, T.C.

1984-01-01

Research on the hydrology of Mirror Lake, (north-central) New Hampshire includes study of evaporation. Presented here are those climatic data needed for energy-budget and mass-transfer studies, including: temperature of lake water surface, dry-bulb and wet-bulb air temperatures, wind speed, precipitation and solar radiation. Data are collected at raft and land stations. (USGS)

Ceramic technology for solar thermal receivers

NASA Technical Reports Server (NTRS)

Kudirka, A. A.; Smoak, R. H.

1981-01-01

The high-temperature capability, resistance to corrosive environments and non-strategic nature of ceramics have prompted applications in the solar thermal field whose advantages over metallic devices of comparable performance may begin to be assessed. It is shown by a survey of point-focusing receiver designs employing a variety of ceramic compositions and fabrication methods that the state-of-the-art in structural ceramics is not sufficiently advanced to fully realize the promised benefits of higher temperature capabilities at lower cost than metallic alternatives. The ceramics considered include alumina, berylia, magnesia, stabilized zirconia, fused silica, silicon nitride, silicon carbide, mullite and cordierite, processed by such methods as isostatic pressing, dry pressing, slip casting, extrusion, calendaring and injection molding.

Making use of renewable energy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnston, J.C.

1984-01-01

This book describes renewable energy projects proposed for the rural areas of developing countries. Topics considered include biogas generation in Zimbabwe, biogas technology for water pumping in Botswana, soil fertility and energy problems in rural development in the Zaire rain forest, international scientific collaboration on biogas technologies for rural development, alcohol from biomass, an ethanol project in Zimbabwe, biomass alcohol and the fuel-food issue, solar water heating in Zimbabwe, absorbent box solar cookers, solar crop drying in Zimbabwe, the use of passive solar energy in Botswana buildings, the potential of mini hydro systems, woodfuel as a potential renewable energy source,more » small-scale afforestation for domestic needs in the communal lands of Zimbabwe, muscle power, the use of human energy in construction, hand-operated water pumps, animal power for water pumping in Botswana, the production of charcoal in Zambia, improving the efficiency of a traditional charcoal-burning Burmese cooking stove, social impacts, non-engineering constraints affecting energy use in a rural area, women and energy, and non-technical factors influencing the establishment of fuels-from-crops industries in developing countries.« less

Seasonal and interannual variations in the influence of cloud cover variability on snowpack and streamflow in the western U.S.

NASA Astrophysics Data System (ADS)

Sumargo, E.; Cayan, D. R.

2016-12-01

Solar radiation (S) is a key driver of snowmelt and water fluxes, but its effect varies depending on time of year and also upon the hydrological character (e.g., dry or wet) of a given year. In this study, we use remote sensed S to quantify cloudiness variability and its effects on snowmelt and streamflow across mountain basins in the western U.S. We utilize 20 years (1996-2015) of NASA/NOAA GOES-derived cloud albedo (αcloud) at 4-km daily samples to estimate S over relatively fine spatial and temporal resolution during Feb-Jul when snowmelt is most active. Daily snow water equivalent (SWE) records from >200 CDEC and SNOTEL locations, along with daily stream discharge (Q) from USGS HCDN records are used to compute day-to-day changes (dSWE and dQ). Multivariate linear regression models of dSWE and dQ are constructed for each month, wherein αcloud from several days prior up to the concurrent day are the predictors. In Feb-May, the results show predominantly negative correlations between αcloud and dSWE, confirming the cloud-shading effect in preserving snowpack and reducing runoff. The influence of cloudiness variability on snowpack, denoted by the coefficient of determination (R2) between the measured and modeled dSWE, amounts 4%-73% over Feb-Jul, averaging 20% in the northwest and 26% in the southwest. The dQ case exhibits similar patterns, but lower explained variance. In Jun-Jul, most locations in both dSWE and dQ cases display positive correlation but with diminished R2, presumably reflecting the drying effect of summertime. In comparing dry and wet years, the R2 is somewhat higher in dry years, suggesting that the importance of cloud cover and the associated solar insolation variability is higher in cases with greater influence from other hydrological factors, including heavy precipitation events and fluctuations associated with a higher snowpack.

Dry-spray deposition of TiO2 for a flexible dye-sensitized solar cell (DSSC) using a nanoparticle deposition system (NPDS).

PubMed

Kim, Min-Saeng; Chun, Doo-Man; Choi, Jung-Oh; Lee, Jong-Cheon; Kim, Yang Hee; Kim, Kwang-Su; Lee, Caroline Sunyong; Ahn, Sung-Hoon

2012-04-01

TiO2 powders were deposited on indium tin oxide (ITO) coated polyethylene terephthalate (PET) substrates for application to the photoelectrode of a dye-sensitized solar cell (DSSC). In the conventional DSSC manufacturing process, a semiconductor oxide such as TiO2 powder requires a sintering process at higher temperature than the glass transition temperature (T(g)) of polymers, and thus utilization of flexible polymer substrates in DSSC research has been constrained. To overcome this restriction related to sintering, we used a nanoparticle deposition system (NPDS) that could produce a thin coating layer through a dry-spray method under atmospheric pressure at room temperature. The powder was sprayed through a slit-type nozzle having a 0.4 x 10 mm2 rectangular outlet. In order to determine the deposited TiO2 thickness, five kinds of TiO2 layered specimens were prepared, where the specimens have single and double layer structures. Deposited powders on the ITO coated PET substrates were observed using FE-SEM and a scan profiler The thicker TiO2 photoelectrode with a DSSC having a double layer structure showed higher energy efficiency than the single layer case. The highest fabricated flexible DSSC displayed a short circuit current density J(sc) = 1.99 mA cm(-2), open circuit voltage V(oc) = 0.71 V, and energy efficiency eta = 0.94%. These results demonstrate the possibility of utilizing the dry-spray method to fabricate a TiO2 layer on flexible polymer substrates at room temperature under atmospheric pressure.

Dry Ice Etches Terrain

NASA Technical Reports Server (NTRS)

2007-01-01

[figure removed for brevity, see original site] Figure 1

Every year seasonal carbon dioxide ice, known to us as 'dry ice,' covers the poles of Mars. In the south polar region this ice is translucent, allowing sunlight to pass through and warm the surface below. The ice then sublimes (evaporates) from the bottom of the ice layer, and carves channels in the surface.

The channels take on many forms. In the subimage shown here (figure 1) the gas from the dry ice has etched wide shallow channels. This region is relatively flat, which may be the reason these channels have a different morphology than the 'spiders' seen in more hummocky terrain.

Observation Geometry Image PSP_003364_0945 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on 15-Apr-2007. The complete image is centered at -85.4 degrees latitude, 104.0 degrees East longitude. The range to the target site was 251.5 km (157.2 miles). At this distance the image scale is 25.2 cm/pixel (with 1 x 1 binning) so objects 75 cm across are resolved. The image shown here has been map-projected to 25 cm/pixel . The image was taken at a local Mars time of 06:57 PM and the scene is illuminated from the west with a solar incidence angle of 75 degrees, thus the sun was about 15 degrees above the horizon. At a solar longitude of 219.6 degrees, the season on Mars is Northern Autumn.

Significant reduction in arc frequency biased solar cells: Observations, diagnostics, and mitigation technique(s)

NASA Technical Reports Server (NTRS)

Upschulte, B. L.; Weyl, G. M.; Marinelli, W. J.; Aifer, E.; Hastings, D.; Snyder, D.

1991-01-01

A variety of experiments were performed which identify key factors contributing to the arcing of negatively biased high voltage solar cells. These efforts have led to reduction of greater than a factor of 100 in the arc frequency of a single cell following proper remediation procedures. Experiments naturally lead to and focussed on the adhesive/encapsulant that is used to bond the protective cover slip to the solar cell. An image-intensified charge coupled device (CCD) camera system recorded UV emission from arc events which occurred exclusively along the interfacial edge between the cover slip and the solar cell. Microscopic inspection of this interfacial region showed a bead of encapsulant along this entire edge. Elimination of this encapsulant bead reduced the arc frequency by two orders of magnitude. Water contamination was also identified as a key contributor which enhances arcing of the encapsulant bead along the solar cell edge. Spectrally resolved measurements of the observable UV light shows a feature assignable to OH(A-X) electronic emission, which is common for water contaminated discharges. Experiments in which the solar cell temperature was raised to 85 C showed a reduced arcing frequency, suggesting desorption of H2O. Exposing the solar cell to water vapor was shown to increase the arcing frequency. Clean dry gases such as O2, N2, and Ar show no enhancement of the arcing rate. Elimination of the exposed encapsulant eliminates any measurable sensitivity to H2O vapor.

The Survival and Resistance of Halobacterium salinarum NRC-1, Halococcus hamelinensis, and Halococcus morrhuae to Simulated Outer Space Solar Radiation.

PubMed

Leuko, S; Domingos, C; Parpart, A; Reitz, G; Rettberg, P

2015-11-01

Solar radiation is among the most prominent stress factors organisms face during space travel and possibly on other planets. Our analysis of three different halophilic archaea, namely Halobacterium salinarum NRC-1, Halococcus morrhuae, and Halococcus hamelinensis, which were exposed to simulated solar radiation in either dried or liquid state, showed tremendous differences in tolerance and survivability. We found that Hcc. hamelinensis is not able to withstand high fluences of simulated solar radiation compared to the other tested organisms. These results can be correlated to significant differences in genomic integrity following exposure, as visualized by random amplified polymorphic DNA (RAPD)-PCR. In contrast to the other two tested strains, Hcc. hamelinensis accumulates compatible solutes such as trehalose for osmoprotection. The addition of 100 mM trehalose to the growth medium of Hcc. hamelinensis improved its survivability following exposure. Exposure of cells in liquid at different temperatures suggests that Hbt. salinarum NRC-1 is actively repairing cellular and DNA damage during exposure, whereas Hcc. morrhuae exhibits no difference in survival. For Hcc. morrhuae, the high resistance against simulated solar radiation may be explained with the formation of cell clusters. Our experiments showed that these clusters shield cells on the inside against simulated solar radiation, which results in better survival rates at higher fluences when compared to Hbt. salinarum NRC-1 and Hcc. hamelinensis. Overall, this study shows that some halophilic archaea are highly resistant to simulated solar radiation and that they are of high astrobiological significance. Halophiles-Solar radiation-Stress resistance-Survival.

Surface etching technologies for monocrystalline silicon wafer solar cells

NASA Astrophysics Data System (ADS)

Tang, Muzhi

With more than 200 GW of accumulated installations in 2015, photovoltaics (PV) has become an important green energy harvesting method. The PV market is dominated by solar cells made from crystalline silicon wafers. The engineering of the wafer surfaces is critical to the solar cell cost reduction and performance enhancement. Therefore, this thesis focuses on the development of surface etching technologies for monocrystalline silicon wafer solar cells. It aims to develop a more efficient alkaline texturing method and more effective surface cleaning processes. Firstly, a rapid, isopropanol alcohol free texturing method is successfully demonstrated to shorten the process time and reduce the consumption of chemicals. This method utilizes the special chemical properties of triethylamine, which can form Si-N bonds with wafer surface atoms. Secondly, a room-temperature anisotropic emitter etch-back process is developed to improve the n+ emitter passivation. Using this method, 19.0% efficient screen-printed aluminium back surface field solar cells are developed that show an efficiency gain of 0.15% (absolute) compared with conventionally made solar cells. Finally, state-of-the-art silicon surface passivation results are achieved using hydrogen plasma etching as a dry alternative to the classical hydrofluoric acid wet-chemical process. The effective native oxide removal and the hydrogenation of the silicon surface are shown to be the reasons for the excellent level of surface passivation achieved with this novel method.

Elastic MCF Rubber with Photovoltaics and Sensing on Hybrid Skin (H-Skin) for Artificial Skin by Utilizing Natural Rubber: 2nd Report on the Effect of Tension and Compression on the Hybrid Photo- and Piezo-Electricity Properties in Wet-Type Solar Cell Rubber.

PubMed

Shimada, Kunio

2018-06-06

In contrast to ordinary solid-state solar cells, a flexible, elastic, extensible and light-weight solar cell has the potential to be extremely useful in many new engineering applications, such as in the field of robotics. Therefore, we propose a new type of artificial skin for humanoid robots with hybrid functions, which we have termed hybrid skin (H-Skin). To realize the fabrication of such a solar cell, we have continued to utilize the principles of ordinary solid-state wet-type or dye-sensitized solar rubber as a follow-up study to the first report. In the first report, we dealt with both photovoltaic- and piezo-effects for dry-type magnetic compound fluid (MCF) rubber solar cells, which were generated because the polyisoprene, oleic acid of the magnetic fluid (MF), and water served as p- and n- semiconductors. In the present report, we deal with wet-type MCF rubber solar cells by using sensitized dyes and electrolytes. Photoreactions generated through the synthesis of these components were investigated by an experiment using irradiation with visible and ultraviolet light. In addition, magnetic clusters were formed by the aggregation of Fe₃O₄ in the MF and the metal particles created the hetero-junction structure of the semiconductors. In the MCF rubber solar cell, both photo- and piezo-electricity were generated using a physical model. The effects of tension and compression on their electrical properties were evaluated. Finally, we experimentally demonstrated the effect of the distance between the electrodes of the solar cell on photoelectricity and built-in electricity.

In Search of Sun-Climate Connection Using Solar Irradiance Measurements and Climate Records

NASA Technical Reports Server (NTRS)

Kiang, Richard K.; Kyle, H. Lee

2000-01-01

The Earth's temperature has risen approximately 0.5 degree-C in the last 150 years. Because the atmospheric concentration of carbon dioxide has increased nearly 30% since the industrial revolution, a common conjecture, supported by various climate models, is that anthropogenic greenhouse gases have contributed to global warming. Another probable factor for the warming is the natural variation of solar irradiance. Although the variation is as small as 0.1 % it is hypothesized that it contributes to part of the temperature rise. Warmer or cooler ocean temperature at one part of the Globe may manifest as abnormally wet or dry weather patterns some months or years later at another part of the globe. Furthermore, the lower atmosphere can be affected through its coupling with the stratosphere, after the stratospheric ozone absorbs the ultraviolet portion of the solar irradiance. In this paper, we use wavelet transforms based on Morlet wavelet to analyze the time-frequency properties in several datasets, including the Radiation Budget measurements, the long-term total solar irradiance time series, the long-term temperature at two locations for the North and the South Hemisphere. The main solar cycle, approximately 11 years, are identified in the long-term total solar irradiance time series. The wavelet transform of the temperature datasets show annual cycle but not the solar cycle. Some correlation is seen between the length of the solar cycle extracted from the wavelet transform and the North Hemisphere temperature time series. The absence of the 11-year cycle in a time series does not necessarily imply that the geophysical parameter is not affected by the solar cycle; rather it simply reflects the complex nature of the Earth's response to climate forcings.

Photovoltaic at Hollywood and Desert Breeze Recreational Centers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ammerman, Shane

Executive Summary Renewable Energy Initiatives for Clark County Parks and Recreation Solar Project DOE grant # DE-EE0003180 In accordance with the goals of the Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy for promoting solar energy as clean, carbon-free and cost-effective, the County believed that a recreational center was an ideal place to promote solar energy technologies to the public. This project included the construction of solar electricity generation facilities (40kW) at two Clark County facility sites, Desert Breeze Recreational Center and Hollywood Recreational Center, with educational kiosks and Green Boxes for classroom instruction. The major objectivesmore » and goals of this Solar Project include demonstration of state of the art technologies for the generation of electricity from solar technology and the creation of an informative and educational tool in regards to the benefits and process of generating alternative energy. Clark County partnered with Anne Johnson (design architect/consultant), Affiliated Engineers Inc. (AEI), Desert Research Institute (DRI), and Morse Electric. The latest photovoltaic technologies were used in the project to help create the greatest expected energy savings for60443 each recreational center. This coupled with the data created from the monitoring system will help Clark County and NREL further understand the real time outputs from the system. The educational portion created with AEI and DRI incorporates material for all ages with a focus on K - 12. The AEI component is an animated story telling the fundamentals of how sunlight is turned into electricity and DRI‘s creation of Solar Green Boxes brings environmental education into the classroom. In addition to the educational component for the public, the energy that is created through the photovoltaic system also translates into saved money and health benefits for the general public. This project has helped Clark County to further add to its own energy reduction goals created by the energy management agenda (Resolution to Encourage Sustainability) and the County’s Eco-initiative. Each site has installed photovoltaic panels on the existing roof structures that exhibit suitable solar exposure. The generation systems utilize solar energy creating electricity used for the facility’s lighting system and other electrical requirements. Unused electricity is sent to the electric utility grid, often at peak demand times. Educational signage, kiosks and information have been included to inform and expand the public’s understanding of solar energy technology. The Solar Green Boxes were created for further hands on classroom education of solar power. In addition, data is sent by a Long Term PV performance monitoring system, complete with data transmission to NREL (National Renewable Energy Laboratory), located in Golden, CO. This system correlates local solar irradiance and weather with power production. The expected outcomes of this Solar Project are as follows: (1) Successful photovoltaic electricity generation technologies to capture solar energy in a useful form of electrical energy. (2) Reduction of greenhouse gas emissions and environmental degradation resulting from reduced energy demand from traditional electricity sources such as fossil fuel fired and nuclear power plants. (3) Advance the research and development of solar electricity generation. (4) The education of the general public in regards to the benefits of environmentally friendly electricity generation and Clark County’s efforts to encourage sustainable living practices. (5) To provide momentum for the nexus for future solar generation facilities in Clark County facilities and buildings and further the County’s energy reduction goals. (6) To ultimately contribute to the reduction of dependence on foreign oil and other unsustainable sources of energy. This Solar Project addresses several objectives and goals of the U.S. Department of Energy’s Solar Energy Technology Program. The project improves the integration and performance of solar electricity directly through implementation of cutting edge technology. The project further addresses this goal by laying important ground work and infrastructure for integration into the utility grid in future related projects. There will also be added security, reliability, and diversity to the energy system by providing and using reliable, secure, distributed electricity in Clark County facilities as well as sending such electricity back into the utility electric grid. A final major objective met by the Solar Project will be the displacement of energy derived by fossil fuels with clean renewable energy created by photovoltaic panels.« less

Method of fabricating vertically aligned group III-V nanowires

DOEpatents

Wang, George T; Li, Qiming

2014-11-25

A top-down method of fabricating vertically aligned Group III-V micro- and nanowires uses a two-step etch process that adds a selective anisotropic wet etch after an initial plasma etch to remove the dry etch damage while enabling micro/nanowires with straight and smooth faceted sidewalls and controllable diameters independent of pitch. The method enables the fabrication of nanowire lasers, LEDs, and solar cells.

All-vapor processing of p-type tellurium-containing II-VI semiconductor and ohmic contacts thereof

DOEpatents

McCandless, Brian E.

2001-06-26

An all dry method for producing solar cells is provided comprising first heat-annealing a II-VI semiconductor; enhancing the conductivity and grain size of the annealed layer; modifying the surface and depositing a tellurium layer onto the enhanced layer; and then depositing copper onto the tellurium layer so as to produce a copper tellurium compound on the layer.

40 CFR 86.162-00 - Approval of alternative air conditioning test simulations and descriptions of AC1 and AC2.

Code of Federal Regulations, 2011 CFR

2011-07-01

... conditioning system compressor, converted to an equivalent roadload component, to the normal dynamometer... driving the SC03 cycle with the air conditioning system operating. (1) Engine revolutions/minute (ERPMt...)(i) (A) and (B) are replaced with 76 °F and 50 grains of water/pound of dry air and the solar heat...

Climatic data for Mirror Lake, West Thornton, New Hampshire, 1984

USGS Publications Warehouse

Sturrock, A.M.; Buso, D.C.; Scarborough, J.L.; Winter, T.C.

1986-01-01

Research on the hydrology of Mirror lake, (north-central) New Hampshire includes study of evaporation. Presented here are those climatic data needed for energy-budget and mass-transfer studies, including: temperature of lake water surface; dry-bulb and wet-bulb air temperatures; wind speed at 3 levels above the water surface; and solar and atmospheric radiation. Data are collected at raft and land stations. (USGS)

Regression Model for MODTRAN with Applications to Inactivation of Microbes Suspended in the Atmosphere by Solar Ultraviolet Radiation

DTIC Science & Technology

2012-05-01

mixed vegetation): 0.007 (0.017) For materials tested, • The albedo levels of old grass, dead grass, burnt grass, and maple leaf at 300 nm were...as 0.016-0.017 over vegetation, 0.04-0.05 over bare fertile soil, and 0.07-0.10 over concrete (autobahn, Germany). The albedo over dry bright sand

Evaluation of two Vaisala RS92 radiosonde solar radiative dry bias correction algorithms

DOE PAGES

Dzambo, Andrew M.; Turner, David D.; Mlawer, Eli J.

2016-04-12

Solar heating of the relative humidity (RH) probe on Vaisala RS92 radiosondes results in a large dry bias in the upper troposphere. Two different algorithms (Miloshevich et al., 2009, MILO hereafter; and Wang et al., 2013, WANG hereafter) have been designed to account for this solar radiative dry bias (SRDB). These corrections are markedly different with MILO adding up to 40 % more moisture to the original radiosonde profile than WANG; however, the impact of the two algorithms varies with height. The accuracy of these two algorithms is evaluated using three different approaches: a comparison of precipitable water vapor (PWV),more » downwelling radiative closure with a surface-based microwave radiometer at a high-altitude site (5.3 km m.s.l.), and upwelling radiative closure with the space-based Atmospheric Infrared Sounder (AIRS). The PWV computed from the uncorrected and corrected RH data is compared against PWV retrieved from ground-based microwave radiometers at tropical, midlatitude, and arctic sites. Although MILO generally adds more moisture to the original radiosonde profile in the upper troposphere compared to WANG, both corrections yield similar changes to the PWV, and the corrected data agree well with the ground-based retrievals. The two closure activities – done for clear-sky scenes – use the radiative transfer models MonoRTM and LBLRTM to compute radiance from the radiosonde profiles to compare against spectral observations. Both WANG- and MILO-corrected RHs are statistically better than original RH in all cases except for the driest 30 % of cases in the downwelling experiment, where both algorithms add too much water vapor to the original profile. In the upwelling experiment, the RH correction applied by the WANG vs. MILO algorithm is statistically different above 10 km for the driest 30 % of cases and above 8 km for the moistest 30 % of cases, suggesting that the MILO correction performs better than the WANG in clear-sky scenes. Lastly, the cause of this statistical significance is likely explained by the fact the WANG correction also accounts for cloud cover – a condition not accounted for in the radiance closure experiments.« less

Evaluation of two Vaisala RS92 radiosonde solar radiative dry bias correction algorithms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dzambo, Andrew M.; Turner, David D.; Mlawer, Eli J.

Solar heating of the relative humidity (RH) probe on Vaisala RS92 radiosondes results in a large dry bias in the upper troposphere. Two different algorithms (Miloshevich et al., 2009, MILO hereafter; and Wang et al., 2013, WANG hereafter) have been designed to account for this solar radiative dry bias (SRDB). These corrections are markedly different with MILO adding up to 40 % more moisture to the original radiosonde profile than WANG; however, the impact of the two algorithms varies with height. The accuracy of these two algorithms is evaluated using three different approaches: a comparison of precipitable water vapor (PWV),more » downwelling radiative closure with a surface-based microwave radiometer at a high-altitude site (5.3 km m.s.l.), and upwelling radiative closure with the space-based Atmospheric Infrared Sounder (AIRS). The PWV computed from the uncorrected and corrected RH data is compared against PWV retrieved from ground-based microwave radiometers at tropical, midlatitude, and arctic sites. Although MILO generally adds more moisture to the original radiosonde profile in the upper troposphere compared to WANG, both corrections yield similar changes to the PWV, and the corrected data agree well with the ground-based retrievals. The two closure activities – done for clear-sky scenes – use the radiative transfer models MonoRTM and LBLRTM to compute radiance from the radiosonde profiles to compare against spectral observations. Both WANG- and MILO-corrected RHs are statistically better than original RH in all cases except for the driest 30 % of cases in the downwelling experiment, where both algorithms add too much water vapor to the original profile. In the upwelling experiment, the RH correction applied by the WANG vs. MILO algorithm is statistically different above 10 km for the driest 30 % of cases and above 8 km for the moistest 30 % of cases, suggesting that the MILO correction performs better than the WANG in clear-sky scenes. Lastly, the cause of this statistical significance is likely explained by the fact the WANG correction also accounts for cloud cover – a condition not accounted for in the radiance closure experiments.« less

High-Frequency Response of the Atmospheric Electric Potential Gradient Under Strong and Dry Boundary-Layer Convection

NASA Astrophysics Data System (ADS)

Conceição, Ricardo; Silva, Hugo Gonçalves; Bennett, Alec; Salgado, Rui; Bortoli, Daniele; Costa, Maria João; Collares Pereira, Manuel

2018-01-01

The spectral response of atmospheric electric potential gradient gives important information about phenomena affecting this gradient at characteristic time scales ranging from years (e.g., solar modulation) to fractions of a second (e.g., turbulence). While long-term time scales have been exhaustively explored, short-term scales have received less attention. At such frequencies, space-charge transport inside the planetary boundary layer becomes a sizeable contribution to the potential gradient variability. For the first time, co-located (Évora, Portugal) measurements of boundary-layer backscatter profiles and the 100-Hz potential gradient are reported. Five campaign days are analyzed, providing evidence for a relation between high-frequency response of the potential gradient and strong dry convection.

Changes in microbiological composition of soils and soil contamination with drug-resistant bacteria caused by the use of sewage sludge in nature

NASA Astrophysics Data System (ADS)

Stanczyk-Mazanek, Ewa; Pasonl, Lukasz; Kepa, Urszula

2017-11-01

This study evaluated the effect of the use of sewage sludge in nature on biological soil parameters. The study was conducted is field experiment environment (small beds). The sandy soil was fertilized with sewage sludge dried naturally (in heaps) and in solar drying facilities. The fertilization was based on the doses of sewage sludge and manure with the amounts of 10, 20, 30 and 40 Mg/ha. The experiment duration was 3 years. The sanitary status of the soils fertilized with the sludge and manure was evaluated (coliform index, Clostridium perfrinens). Furthermore, the content of pathogenic bacteria was evaluated, with determination of its resistance to first-line antibiotics.

Interface engineering of Cu(In,Ga)Se2 and atomic layer deposited Zn(O,S) heterojunctions

NASA Astrophysics Data System (ADS)

Schmidt, Sebastian S.; Merdes, Saoussen; Steigert, Alexander; Klenk, Reiner; Kaufmann, Christian A.; Simsek Sanli, Ekin; van Aken, Peter A.; Oertel, Mike; Schneikart, Anja; Dimmler, Bernhard; Schlatmann, Rutger

2017-08-01

Atomic layer deposition of Zn(O,S) is an attractive dry and Cd-free process for the preparation of buffer layers for chalcopyrite solar modules. As we previously reported, excellent cell and module efficiencies were achieved using absorbers from industrial pilot production. These absorbers were grown using a selenization/sulfurization process. In this contribution we report on the interface engineering required to adapt the process to sulfur-free multi source evaporated absorbers. Different approaches to a local sulfur enrichment at the heterojunction have been studied by using surface analysis (XPS) and scanning transmission electron microscopy. We correlate the microstructure and element distribution at the interface with device properties obtained by electronic characterization. The optimized completely dry process yields cell efficiencies >16% and 30 × 30 cm2 minimodule efficiencies of up to 13.9% on industrial substrates. Any degradation observed in the dry heat stress test is fully reversible after light soaking.

Constraining global dry deposition of ozone: observations and modeling

NASA Astrophysics Data System (ADS)

Silva, S. J.; Heald, C. L.

2016-12-01

Ozone loss through dry deposition to vegetation is a critically important process for both air quality and ecosystem health. Current estimates are that nearly 25% of all surface ozone is destroyed through dry deposition, and billions of dollars are lost annually due to losses of ecosystem services and agricultural yield associated with ozone damage. However there are still substantial uncertainties regarding the spatial distribution and magnitude of the global depositional flux. As land cover change continues throughout this century, dry deposition of ozone will change in ways that are yet still poorly understood. Nearly every major atmospheric chemistry model uses a variation of the "resistor in series parameterization" for the calculation of dry deposition. By far the most commonly implemented parameterization is of the form presented in Wesely (1989), and is dependent on many variables, including land type look up tables, solar radiation, leaf area index, temperature, and more. The uncertainties contained within the various parts of this parameterization have to date not been fully explored. A lack of understanding of these uncertainties, coupled with a dearth of routine measurements of ozone deposition, ultimately challenges our ability to understand the impacts of land cover change on surface ozone. In this work, we use a suite of globally-distributed observations from the past two decades and the GEOS-Chem chemical transport model to constrain global dry deposition, improve our understanding of these uncertainties, and contextualize the impact of land cover change on ozone concentrations.

CH3NH3I treatment temperature of 70 °C in low-pressure vapor-assisted deposition for mesoscopic perovskite solar cells

NASA Astrophysics Data System (ADS)

Jin, Wenbin; Zou, Xiaoping; Bai, Xiao; Yang, Ying; Chen, Dan

2018-01-01

Herein, we report a modified vapor-assisted deposition method to fabricate CH3NH3PbI3 film at 70 °C in a vacuum drying oven. The modified method has excellent operability and expandability in preparing perovskite solar cells. The CH3NH3I treatment temperature is 130 °C or 150 °C in conventional method, but we reduced the temperature to 70 °C in the modified vapor-assisted method. Meanwhile, the quality of CH3NH3PbI3 films prepared via the modified method is superior to that of CH3NH3PbI3 films of solution-processed method.

Soiling of building envelope surfaces and its effect on solar reflectance. Part I: Analysis of roofing product databases

DOE PAGES

Sleiman, Mohamad; Ban-Weiss, George; Gilbert, Haley E.; ...

2011-12-01

The use of highly reflective “cool” roofing materials can decrease demand for air conditioning, mitigate the urban heat island effect, and potentially slow global warming. However, initially high roof solar reflectance can be degraded by natural soiling and weathering processes. We evaluated solar reflectance losses after three years of natural exposure reported in two separate databases: the Rated Products Directory of the US Cool Roof Rating Council (CRRC) and information reported by manufacturers to the US Environmental Protection Agency (EPA)’s ENERGY STAR® rating program. Many product ratings were culled because they were duplicative (within a database) or not measured. Amore » second, site-resolved version of the CRRC dataset was created by transcribing from paper records the site-specific measurements of aged solar reflectance in Florida, Arizona and Ohio. Products with high initial solar reflectance tended to lose reflectance, while those with very low initial solar reflectance tended to become more reflective as they aged. Within the site-resolved CRRC database, absolute solar reflectance losses for samples of medium-to-high initial solar reflectance were 2 - 3 times greater in Florida (hot and humid) than in Arizona (hot and dry); losses in Ohio (temperate but polluted) were intermediate. Disaggregating results by product type, factory-applied coating, field-applied coating, metal, modified bitumen, shingle, singleply membrane and tile, revealed that absolute solar reflectance losses were largest for fieldapplied coating, modified bitumen and single-ply membrane products, and smallest for factoryapplied coating and metal products.The 2008 Title 24 provisional aged solar reflectance formula overpredicts the measured aged solar reflectance of 0% to 30% of each product type in the culled public CRRC database. The rate of overprediction was greatest for field-applied coating and single-ply membrane products and least for factory-applied coating, shingle, and metal products. New product-specific formulas can be used to estimate provisional aged solar reflectance from initial solar reflectance pending measurement of aged solar reflectance. The appropriate value of soiling resistance varies by product type and is selected to attain some desired overprediction rate for the formula. The correlations for shingle products presented in this paper should not be used to predict aged solar reflectance or estimate provisional aged solar reflectance because the data set is too small and too limited in range of initial solar reflectance.« less

Reconstructed Solar-Induced Fluorescence: A Machine Learning Vegetation Product Based on MODIS Surface Reflectance to Reproduce GOME-2 Solar-Induced Fluorescence

NASA Astrophysics Data System (ADS)

Gentine, P.; Alemohammad, S. H.

2018-04-01

Solar-induced fluorescence (SIF) observations from space have resulted in major advancements in estimating gross primary productivity (GPP). However, current SIF observations remain spatially coarse, infrequent, and noisy. Here we develop a machine learning approach using surface reflectances from Moderate Resolution Imaging Spectroradiometer (MODIS) channels to reproduce SIF normalized by clear sky surface irradiance from the Global Ozone Monitoring Experiment-2 (GOME-2). The resulting product is a proxy for ecosystem photosynthetically active radiation absorbed by chlorophyll (fAPARCh). Multiplying this new product with a MODIS estimate of photosynthetically active radiation provides a new MODIS-only reconstruction of SIF called Reconstructed SIF (RSIF). RSIF exhibits much higher seasonal and interannual correlation than the original SIF when compared with eddy covariance estimates of GPP and two reference global GPP products, especially in dry and cold regions. RSIF also reproduces intense productivity regions such as the U.S. Corn Belt contrary to typical vegetation indices and similarly to SIF.

Effect of sintering time on the performance of turmeric dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Basuki, Hidajat, R. Lullus Lambang G.; Suyitno, Kristiawan, Budi; Rachmanto, Rendy Adhi

2017-01-01

This study reports the effect of sintering time on the performance of the dye-sensitized solar cells with turmeric dyes as sensitizers. Sintering TiO2 semiconductors were conducted at a temperature of 450°C for 30, 50, 90, 120, 150, and 180 minutes. The natural dye was extracted from dried turmeric powders with ethanol solvent. The results show that size of grains and the opening area of TiO2 semiconductor depended on the sintering time. The improvement of the properties of TiO2 semiconductor allowed more turmeric dyes were adsorbed by the semiconductors and then improved the performance of solar cells. The sintering time of 150 minutes produced large grains with an average diameter of 68.87 nm, and a porosity area of 26.51% caused the performance of DSSCs was the highest among other sintering time. The Voc, Jsc, and efficiency of DSSCs with turmeric-based natural dyes 0.64 V, 0.47 mA/cm2, and 0.2%, respectively.

Solar Energy Development and Aquatic Ecosystems in the Southwestern United States: Potential Impacts, Mitigation, and Research Needs

NASA Astrophysics Data System (ADS)

Grippo, Mark; Hayse, John W.; O'Connor, Ben L.

2015-01-01

The cumulative impacts of utility-scale solar energy facilities on aquatic ecosystems in the Southwestern United States are of concern, considering the many existing regional anthropogenic stressors. We review the potential impacts of solar energy development on aquatic habitat and biota. The greatest potential for impacts is related to the loss, fragmentation, or prolonged drying of ephemeral water bodies and drainage networks resulting from the loss of desert washes within the construction footprint of the facility. Groundwater-dependent aquatic habitat may also be affected by operational groundwater withdrawal in the case of water-intensive solar technologies. Solar panels have also been found to attract aquatic insects and waterbirds, potentially resulting in mortality. Avoiding construction activity near perennial and intermittent surface waters is the primary means of reducing impacts on aquatic habitats, followed by measures to minimize erosion, sedimentation, and contaminant inputs into waterways. Currently, significant data gaps make solar facility impact assessment and mitigation more difficult. Examples include the need for more regional and site-specific studies of surface-groundwater connectivity, more detailed maps of regional stream networks and riparian vegetation corridors, as well as surveys of the aquatic communities inhabiting ephemeral streams. In addition, because they often lack regulatory protection, there is also a need to develop valuation criteria for ephemeral waters based on their ecological and hydrologic function within the landscape. By addressing these research needs, we can achieve the goal of greater reliance on solar energy, while at the same time minimizing impacts on desert ecosystems.

Solar energy development and aquatic ecosystems in the southwestern United States: potential impacts, mitigation, and research needs.

PubMed

Grippo, Mark; Hayse, John W; O'Connor, Ben L

2015-01-01

The cumulative impacts of utility-scale solar energy facilities on aquatic ecosystems in the Southwestern United States are of concern, considering the many existing regional anthropogenic stressors. We review the potential impacts of solar energy development on aquatic habitat and biota. The greatest potential for impacts is related to the loss, fragmentation, or prolonged drying of ephemeral water bodies and drainage networks resulting from the loss of desert washes within the construction footprint of the facility. Groundwater-dependent aquatic habitat may also be affected by operational groundwater withdrawal in the case of water-intensive solar technologies. Solar panels have also been found to attract aquatic insects and waterbirds, potentially resulting in mortality. Avoiding construction activity near perennial and intermittent surface waters is the primary means of reducing impacts on aquatic habitats, followed by measures to minimize erosion, sedimentation, and contaminant inputs into waterways. Currently, significant data gaps make solar facility impact assessment and mitigation more difficult. Examples include the need for more regional and site-specific studies of surface-groundwater connectivity, more detailed maps of regional stream networks and riparian vegetation corridors, as well as surveys of the aquatic communities inhabiting ephemeral streams. In addition, because they often lack regulatory protection, there is also a need to develop valuation criteria for ephemeral waters based on their ecological and hydrologic function within the landscape. By addressing these research needs, we can achieve the goal of greater reliance on solar energy, while at the same time minimizing impacts on desert ecosystems.

Soil water content and evaporation determined by thermal parameters obtained from ground-based and remote measurements

NASA Technical Reports Server (NTRS)

Reginato, R.; Idso, S.; Vedder, J.; Jackson, R.; Blanchard, M.; Goettelman, R.

1975-01-01

A procedure is presented for calculating 24-hour totals of evaporation from wet and drying soils. Its application requires a knowledge of the daily solar radiation, the maximum and minimum, air temperatures, moist surface albedo, and maximum and minimum surface temperatures. Tests of the technique on a bare field of Avondale loam at Phoenix, Arizona showed it to be independent of season.

Automated Continuous Commissioning of Commercial Buildings

DTIC Science & Technology

2011-09-01

matched pair of supply and return chilled water temperature sensors, a pyranometer , and aspirated wet and dry bulb temperature sensors for the weather...temp X Aspirated weather station is required. Outside air wet bulb X Pyranometer X Wind speed & direction X Main power meter X Lighting load power X...Aspirated weather station is required. Outside air wet bulb X Pyranometer X Provides measurements on global horizontal solar radiation, beam radiation and

Foreign Food Technology of Military Significance. Volume 5, Number 1,

DTIC Science & Technology

1981-12-18

of Simple Solar Dehydrators for Drying Fruit and Vegetable Products Researchers at the Central Mango Research Station, Indian Institute of...dehydration, (raw) slices 4 to 5 mm thick, 30 to 40 mm slices were long. Immersed for 10 minutes in 0.2% powdered. potassium metabisulfite (KMS) solution...years for liquids, primarily milk products and fruit juices , and for products no more viscous than pudding. Further development of aseptic canning

Multi-criteria decision analysis of concentrated solar power with thermal energy storage and dry cooling.

PubMed

Klein, Sharon J W

2013-12-17

Decisions about energy backup and cooling options for parabolic trough (PT) concentrated solar power have technical, economic, and environmental implications. Although PT development has increased rapidly in recent years, energy policies do not address backup or cooling option requirements, and very few studies directly compare the diverse implications of these options. This is the first study to compare the annual capacity factor, levelized cost of energy (LCOE), water consumption, land use, and life cycle greenhouse gas (GHG) emissions of PT with different backup options (minimal backup (MB), thermal energy storage (TES), and fossil fuel backup (FF)) and different cooling options (wet (WC) and dry (DC). Multicriteria decision analysis was used with five preference scenarios to identify the highest-scoring energy backup-cooling combination for each preference scenario. MB-WC had the highest score in the Economic and Climate Change-Economy scenarios, while FF-DC and FF-WC had the highest scores in the Equal and Availability scenarios, respectively. TES-DC had the highest score for the Environmental scenario. DC was ranked 1-3 in all preference scenarios. Direct comparisons between GHG emissions and LCOE and between GHG emissions and land use suggest a preference for TES if backup is require for PT plants to compete with baseload generators.

Sewage sludge drying by energy recovery from OFMSW composting: preliminary feasibility evaluation.

PubMed

Rada, Elena Cristina; Ragazzi, Marco; Villotti, Stefano; Torretta, Vincenzo

2014-05-01

In this paper an original energy recovery method from composting is analyzed. The integrated system exploits the heat available from the aerobic biochemical process in order to support the drying of sewage sludge, using a specific solar greenhouse. The aim is to tackle the problem of organic waste treatment, with specific regard to food waste. This is done by optimizing the energy consumption of the aerobic process of composting, using the heat produced to solve a second important waste management problem such as the sewage waste treatment. Energy and mass balances are presented in a preliminary feasibility study. Referring to a composting plant with a capacity of 15,000 t/y of food waste, the estimation of the power from recovered heat for the entire plant resulted about 42 kW. The results demonstrated that the energy recoverable can cover part of the heat necessary for the treatment of sludge generated by the population served by the composting plant (in terms of food waste and green waste collection). The addition of a renewable source such as solar energy could cover the residual energy demand. The approach is presented in detail in order for it to be replicated in other case studies or at full scale applications. Copyright © 2014 Elsevier Ltd. All rights reserved.

Performance analysis of phase-change material storage unit for both heating and cooling of buildings

NASA Astrophysics Data System (ADS)

Waqas, Adeel; Ali, Majid; Ud Din, Zia

2017-04-01

Utilisation of solar energy and the night ambient (cool) temperatures are the passive ways of heating and cooling of buildings. Intermittent and time-dependent nature of these sources makes thermal energy storage vital for efficient and continuous operation of these heating and cooling techniques. Latent heat thermal energy storage by phase-change materials (PCMs) is preferred over other storage techniques due to its high-energy storage density and isothermal storage process. The current study was aimed to evaluate the performance of the air-based PCM storage unit utilising solar energy and cool ambient night temperatures for comfort heating and cooling of a building in dry-cold and dry-hot climates. The performance of the studied PCM storage unit was maximised when the melting point of the PCM was ∼29°C in summer and 21°C during winter season. The appropriate melting point was ∼27.5°C for all-the-year-round performance. At lower melting points than 27.5°C, declination in the cooling capacity of the storage unit was more profound as compared to the improvement in the heating capacity. Also, it was concluded that the melting point of the PCM that provided maximum cooling during summer season could be used for winter heating also but not vice versa.

Office-like Test Chambers to Measure Cool Roof Energy Savings in Four Indian Climates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arumugam, Rathish; B, Sasank; T, Rajappa

Selecting a high albedo (solar reflectance) waterproofing layer on the top of a roof helps lower the roof’s surface temperature and reduce the air conditioning energy consumption in the top floor of a building. The annual energy savings depend on factors including weather, internal loads, and building operation schedule. To demonstrate the energy saving potential of high albedo roofs, an apparatus consisting of two nearly identical test chambers (A and B) has been built in four Indian climates: Chennai (hot & humid), Bangalore (temperate), Jhagadia (Hot & dry) and Delhi (composite). Each chamber has well-insulated walls to mimic the coremore » of an office building. Both chambers have the same construction, equipment, and operating schedule, differing only in roof surface. The reinforced cement concrete roof of Chamber A is surfaced with a low-albedo cement layer, while that of Chamber B is surfaced with a high-albedo water proof membrane (change in solar reflectance of 0.28). The experiment will be carried out for one year to explore seasonal variations in energy savings. Initial results in the month of July (post summer) shows that savings from high albedo roof ranges from 0.04 kWh/m2/day in temperate climates, to 0.08 kWh/m2/day in hot & dry climate.« less

Potential Regrowth and Recolonization of Salmonellae and Indicators in Biosolids and Biosolid-Amended Soil

PubMed Central

Zaleski, Kathleen J.; Josephson, Karen L.; Gerba, Charles P.; Pepper, Ian L.

2005-01-01

This study evaluated the potential for conversion of Class B to Class A biosolids with respect to salmonellae and fecal coliforms during solar drying in concrete lined drying beds. Anaerobically (8% solids) and aerobically (2% solids) digested Class B biosolids were pumped into field-scale drying beds, and microbial populations and environmental conditions were monitored. Numbers of fecal coliforms and salmonellae decreased as temperature and rate of desiccation increased. After 3 to 4 weeks, Class A requirements were achieved in both biosolids for the pathogens and the indicators. However, following rainfall events, significant increase in numbers was observed for both fecal coliforms and salmonellae. In laboratory studies, regrowth of fecal coliforms was observed in both biosolids and biosolid-amended soil, but the regrowth of salmonellae observed in the concrete-lined drying beds did not occur. These laboratory studies demonstrated that pathogens decreased in numbers when soil was amended with biosolids. Based on serotyping, the increased numbers of salmonellae seen in the concrete lined drying beds following rainfall events was most likely due to recolonization due to contamination from fecal matter introduced by animals and not from regrowth of salmonellae indigenous to biosolids. Overall, we conclude that the use of concrete-lined beds created a situation in which moisture added as rainfall accumulated in the beds, promoting the growth of fecal coliforms and salmonellae added from external sources. PMID:16000779

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoekman, S. Kent; Broch, Broch; Robbins, Curtis

The primary objective of this project was to utilize a flexible, energy-efficient facility, called the DRI Renewable Energy Experimental Facility (REEF) to support various renewable energy research and development (R&D) efforts, along with education and outreach activities. The REEF itself consists of two separate buildings: (1) a 1200-ft2 off-grid capable house and (2) a 600-ft2 workshop/garage to support larger-scale experimental work. Numerous enhancements were made to DRI's existing renewable power generation systems, and several additional components were incorporated to support operation of the REEF House. The power demands of this house are satisfied by integrating and controlling PV arrays, solarmore » thermal systems, wind turbines, an electrolyzer for renewable hydrogen production, a gaseous-fuel internal combustion engine/generator set, and other components. Cooling needs of the REEF House are satisfied by an absorption chiller, driven by solar thermal collectors. The REEF Workshop includes a unique, solar air collector system that is integrated into the roof structure. This system provides space heating inside the Workshop, as well as a hot water supply. The Workshop houses a custom-designed process development unit (PDU) that is used to convert woody biomass into a friable, hydrophobic char that has physical and chemical properties similar to low grade coal. Besides providing sufficient space for operation of this PDU, the REEF Workshop supplies hot water that is used in the biomass treatment process. The DRI-REEF serves as a working laboratory for evaluating and optimizing the performance of renewable energy components within an integrated, residential-like setting. The modular nature of the system allows for exploring alternative configurations and control strategies. This experimental test bed is also highly valuable as an education and outreach tool both in providing an infrastructure for student research projects, and in highlighting renewable energy features to the public.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grippo, Mark; Hayse, John W.; O’Connor, Ben L.

The cumulative impacts of utility-scale solar energy facilities on aquatic ecosystems in the Southwestern United States are of concern, considering the many existing regional anthropogenic stressors. We review the potential impacts of solar energy development on aquatic habitat and biota. The greatest potential for impacts is related to the loss, fragmentation, or prolonged drying of ephemeral water bodies and drainage networks resulting from the loss of desert washes within the construction footprint of the facility. Groundwater-dependent aquatic habitat may also be affected by operational groundwater withdrawal in the case of water-intensive solar technologies. Solar panels have also been found tomore » attract aquatic insects and waterbirds, potentially resulting in mortality. Avoiding construction activity near perennial and intermittent surface waters is the primary means of reducing impacts on aquatic habitats, followed by measures to minimize erosion, sedimentation, and contaminant inputs into waterways. Currently, significant data gaps make solar facility impact assessment and mitigation more difficult. Examples include the need for more regional and site-specific studies of surface–groundwater connectivity, more detailed maps of regional stream networks and riparian vegetation corridors, as well as surveys of the aquatic communities inhabiting ephemeral streams. In addition, because they often lack regulatory protection, there is also a need to develop valuation criteria for ephemeral waters based on their ecological and hydrologic function within the landscape. By addressing these research needs, we can achieve the goal of greater reliance on solar energy, while at the same time minimizing impacts on desert ecosystems.« less

Airborne Sun photometry and Closure Studies in SAFARI-2000 Dry Season Campaign

NASA Technical Reports Server (NTRS)

Schmid, B.; Russell, P. B.; Pilewskie, P.; Redemann, J.; Livingston, J. M.; Hobbs, P. V.; Welton, E. J.; Campbell, J.; Holben, B. N.; McGill, M.;

Impact on Vitamin D2, Vitamin D4 and Agaritine in Agaricus bisporus Mushrooms after Artificial and Natural Solar UV Light Exposure.

PubMed

Urbain, Paul; Valverde, Juan; Jakobsen, Jette

2016-09-01

Commercial mushroom production can expose mushrooms post-harvest to UV light for purposes of vitamin D2 enrichment by converting the naturally occurring provitamin D2 (ergosterol). The objectives of the present study were to artificially simulate solar UV-B doses occurring naturally in Central Europe and to investigate vitamin D2 and vitamin D4 production in sliced Agaricus bisporus (button mushrooms) and to analyse and compare the agaritine content of naturally and artificially UV-irradiated mushrooms. Agaritine was measured for safety aspects even though there is no rationale for a link between UV light exposure and agaritine content. The artificial UV-B dose of 0.53 J/cm(2) raised the vitamin D2 content to significantly (P < 0.001) higher levels of 67.1 ± 9.9 μg/g dry weight (DW) than sun exposure (3.9 ± 0.8 μg/g dry DW). We observed a positive correlation between vitamin D4 and vitamin D2 production (r(2) = 0.96, P < 0.001) after artificial UV irradiation, with vitamin D4 levels ranging from 0 to 20.9 μg/g DW. The agaritine content varied widely but remained within normal ranges in all samples. Irrespective of the irradiation source, agaritine dropped dramatically in conjunction with all UV-B doses both artificial and natural solar, probably due to its known instability. The biological action of vitamin D from UV-exposed mushrooms reflects the activity of these two major vitamin D analogues (D2, D4). Vitamin D4 should be analysed and agaritine disregarded in future studies of UV-exposed mushrooms.

PISCES: A "Stepping Stone" to International Space Exploration and Development

NASA Technical Reports Server (NTRS)

Howell, Joe T.; Henley, Mark W.; Schowengerdt, Frank

2007-01-01

The Pacific International Space Center for Exploration Systems (PISCES) was initiated by the Japan/US Science, Technology and Space Application Programs (JUSTSAP) to advance research and education in space exploration technology and systems working closely with the State of Hawaii. Hawaii has a heritage with space exploration including the training of Apollo astronauts and testing of lunar rover systems in some of the most realistic terrestrial sites available. The high altitude dry environment with greater solar insolation, and the dry lunar regolith-like volcanic ash and cratered terrain make Hawaiian sites ideal to support, international space exploration technology development, demonstration, education and training. This paper will summarize development and roles of PISCES in lunar surface analogs, simulations, technology demonstrations, research and training for space exploration technology and systems.

A nutribusiness strategy for processing and marketing animal-source foods for children.

PubMed

Mills, Edward W; Seetharaman, Koushik; Maretzki, Audrey N

2007-04-01

Nutritional benefits of animal source foods in the diets of children in developing countries indicate a need to increase the availability of such foods to young children. A nutribusiness strategy based on a dried meat and starch product could be used to increase children's access to such foods. The "Chiparoo" was developed at The Pennsylvania State University with this objective in mind. Plant-based and meat ingredients of the Chiparoo are chosen based on regional availability and cultural acceptability. Chiparoo processing procedures, including solar drying, are designed to ensure product safety and to provide product properties that allow them to be eaten as a snack or crumbled into a weaning porridge. Continued work is needed to develop formulation and processing variations that accommodate the needs of cultures around the world.

Dawn Mission: A Journey in Space and Time

NASA Technical Reports Server (NTRS)

Russell, C. T.; Coradini, A.; DeSanctis, M. C.; Feldman, W. C.; Jaumann, R.; Konopliv, A. S.; McCord, T. B.; McFadden, L. A.; McSween, H. Y.; Mottola, S.

2003-01-01

By successively orbiting both 4 Vesta and 1 Ceres the Dawn mission directly addresses the longstanding goals of NASA and the planetary community to understand the origin and evolution of the solar system by obtaining geophysical and geochemical data on diverse main belt asteroids. Ceres and Vesta are two complementary terrestrial protoplanets (one apparently "wet" and one "dry"), whose accretion was terminated by the formation of Jupiter. Ceres is little changed since it formed in the early solar system, while Vesta has experienced significant heating and differentiation. Both have remained intact over the age of the solar system, thereby retaining a record of events and processes from the time of planet formation. Detailed study of the geophysics and geochemistry of these two bodies provides critical benchmarks for the early solar system conditions and processes that shaped its subsequent evolution. Dawn provides the missing context for both primitive and evolved meteoritic data, thus playing a central role in understanding terrestrial planet formation and the evolution of the asteroid belt. Dawn is to be launched in May 2006 arriving at Vesta in 2010 and Ceres in 2014, stopping at each to make 11 months of orbital measurements. The spacecraft uses solar electric propulsion both in cruise and in orbit to make most efficient use of its xenon propellant. The spacecraft carries a framing camera, visible and infrared mapping spectrometer, gamma ray/neutron spectrometer, a laser altimeter, magnetometer, and radio science.

Amide-Catalyzed Phase-Selective Crystallization Reduces Defect Density in Wide-Bandgap Perovskites.

PubMed

Kim, Junghwan; Saidaminov, Makhsud I; Tan, Hairen; Zhao, Yicheng; Kim, Younghoon; Choi, Jongmin; Jo, Jea Woong; Fan, James; Quintero-Bermudez, Rafael; Yang, Zhenyu; Quan, Li Na; Wei, Mingyang; Voznyy, Oleksandr; Sargent, Edward H

2018-03-01

Wide-bandgap (WBG) formamidinium-cesium (FA-Cs) lead iodide-bromide mixed perovskites are promising materials for front cells well-matched with crystalline silicon to form tandem solar cells. They offer avenues to augment the performance of widely deployed commercial solar cells. However, phase instability, high open-circuit voltage (V oc ) deficit, and large hysteresis limit this otherwise promising technology. Here, by controlling the crystallization of FA-Cs WBG perovskite with the aid of a formamide cosolvent, light-induced phase segregation and hysteresis in perovskite solar cells are suppressed. The highly polar solvent additive formamide induces direct formation of the black perovskite phase, bypassing the yellow phases, thereby reducing the density of defects in films. As a result, the optimized WBG perovskite solar cells (PSCs) (E g ≈ 1.75 eV) exhibit a high V oc of 1.23 V, reduced hysteresis, and a power conversion efficiency (PCE) of 17.8%. A PCE of 15.2% on 1.1 cm 2 solar cells, the highest among the reported efficiencies for large-area PSCs having this bandgap is also demonstrated. These perovskites show excellent phase stability and thermal stability, as well as long-term air stability. They maintain ≈95% of their initial PCE after 1300 h of storage in dry air without encapsulation. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Effect of Reduced Water Availability in the Great Ruaha River on the Vulnerable Common Hippopotamus in the Ruaha National Park, Tanzania.

PubMed

Stommel, Claudia; Hofer, Heribert; East, Marion L

2016-01-01

In semi-arid environments, 'permanent' rivers are essential sources of surface water for wildlife during 'dry' seasons when rainfall is limited or absent, particularly for species whose resilience to water scarcity is low. The hippopotamus (Hippopotamus amphibius) requires submersion in water to aid thermoregulation and prevent skin damage by solar radiation; the largest threat to its viability are human alterations of aquatic habitats. In the Ruaha National Park (NP), Tanzania, the Great Ruaha River (GRR) is the main source of surface water for wildlife during the dry season. Recent, large-scale water extraction from the GRR by people upstream of Ruaha NP is thought to be responsible for a profound decrease in dry season water-flow and the absence of surface water along large sections of the river inside the NP. We investigated the impact of decreased water flow on daytime hippo distribution using regular censuses at monitoring locations, transects and camera trap records along a 104km section of the GRR within the Ruaha NP during two dry seasons. The minimum number of hippos per monitoring location increased with the expanse of surface water as the dry seasons progressed, and was not affected by water quality. Hippo distribution significantly changed throughout the dry season, leading to the accumulation of large numbers in very few locations. If surface water loss from the GRR continues to increase in future years, this will have serious implications for the hippo population and other water dependent species in Ruaha NP.

Parameterizations of Dry Deposition for the Industrial Source Complex Model

NASA Astrophysics Data System (ADS)

Wesely, M. L.; Doskey, P. V.; Touma, J. S.

2002-05-01

Improved algorithms have been developed to simulate the dry deposition of hazardous air pollutants (HAPs) with the Industrial Source Complex model system. The dry deposition velocities are described in conventional resistance schemes, for which micrometeorological formulas are applied to describe the aerodynamic resistances above the surface. Pathways to uptake of gases at the ground and in vegetative canopies are depicted with several resistances that are affected by variations in air temperature, humidity, solar irradiance, and soil moisture. Standardized land use types and seasonal categories provide sets of resistances to uptake by various components of the surface. To describe the dry deposition of the large number of gaseous organic HAPS, a new technique based on laboratory study results and theoretical considerations has been developed to provide a means to evaluate the role of lipid solubility on uptake by the waxy outer cuticle of vegetative plant leaves. The dry deposition velocities of particulate HAPs are simulated with a resistance scheme in which deposition velocity is described for two size modes: a fine mode with particles less than about 2.5 microns in diameter and a coarse mode with larger particles but excluding very coarse particles larger than about 10 microns in diameter. For the fine mode, the deposition velocity is calculated with a parameterization based on observations of sulfate dry deposition. For the coarse mode, a representative settling velocity is assumed. Then the total deposition velocity is estimated as the sum of the two deposition velocities weighted according to the amount of mass expected in the two modes.

Application of Solar Electric Propulsion to a Comet Surface Sample Return Mission

NASA Technical Reports Server (NTRS)

Cupples, Mike; Coverstone, Victoria; Woo, Byoungsam

2004-01-01

Current NSTAR (planned for the Discovery Mission: Dawn) and NASA's Evolutionary Xenon Thruster based propulsion systems were compared for a comet surface sample return mission to Tempe1 1. Mission and systems analyses were conducted over a range of array power for each propulsion system with an array of 12 kW EOL at 1 AU chosen for a baseline. Engine configurations investigated for NSTAR included 4 operational engines with 1 spare and 5 operational engines with 1 spare. The NEXT configuration investigated included 2 operational engines plus 1 spare, with performance estimated for high thrust and high Isp throttling modes. Figures of merit for this comparison include Solar Electric Propulsion dry mass, average engine throughput, and net non-propulsion payload returned to Earth flyby.

The Thermal Collector With Varied Glass Covers

NASA Astrophysics Data System (ADS)

Luminosu, I.; Pop, N.

2010-08-01

The thermal collector with varied glass covers represents an innovation realized in order to build a collector able to reach the desired temperature by collecting the solar radiation from the smallest surface, with the highest efficiency. In the case of the thermal collector with variable cover glasses, the number of the glass plates covering the absorber increases together with the length of the circulation pipe for the working fluid. The thermal collector with varied glass covers compared to the conventional collector better meet user requirements because: for the same temperature increase, has the collecting area smaller; for the same collection area, realizes the highest temperature increase and has the highest efficiency. This works is addressed to researchers in the solar energy and to engineers responsible with air-conditioning systems design or industrial and agricultural products drying.

Dynamics of Photoexcitation and Photocatalysis at Nanostructured Carbon Interfaces

DTIC Science & Technology

2015-07-14

nanotubes with a sacrificial polymer and eliminating the polymer using a critical point drying process. This process creates aerogel structures that...Bindl DJ, Jacobberger RM, Wu M-Y, Singha Roy S, Arnold MS, Semiconducting Carbon Nanotube Aerogel Bulk Heterojunction Solar Cells, Small 10 (16), pp...ACS Nano 2015, 9 (1), 564-572. Ye Y, Bindl DJ, Jacobberger RM, Wu M-Y, Singha Roy S, Arnold MS, Semiconducting Carbon Nanotube Aerogel Bulk

Climatic data for Williams Lake, Hubbard County, Minnesota, 1982

USGS Publications Warehouse

Rosenberry, D.O.; Sturrock, A.M.; Scarborough, J.L.; Winter, T.C.

1988-01-01

Research on the hydrology of Williams Lake, north-central Minnesota includes study of evaporation. Those climatic data needed for energy budget and mass transfer studies are presented , including: water surface temperature, dry-bulb and wet-bulb air temperatures, wind speed, precipitation, and solar and atmospheric radiation. Some calculated values necessary for these studies are also presented, such as vapor pressure and Bowen-ratio values. Data are collected at raft and land stations.

Climatic data for Williams Lake, Hubbard County, Minnesota, 1986

USGS Publications Warehouse

Rosenberry, D.O.; Sturrock, A.M.; Winter, T.C.

1988-01-01

Research on the hydrology of Williams Lake, north-central Minnesota includes study of evaporation. Presented here are those climatic data needed for energy-budget and mass-transfer studies, including: water-surface temperature, dry-bulb and wet-bulb air temperatures, wind speed, precipitation, and solar and atmospheric radiation. Some calculated values necessary for these studies, such as vapor pressure and Bowen ratio numbers, also are presented. Data are collected at raft and land stations.

The ancient Egyptian civilization: maximum and minimum in coincidence with solar activity

NASA Astrophysics Data System (ADS)

Shaltout, M.

It is proved from the last 22 years observations of the total solar irradiance (TSI) from space by artificial satellites, that TSI shows negative correlation with the solar activity (sunspots, flares, and 10.7cm Radio emissions) from day to day, but shows positive correlations with the same activity from year to year (on the base of the annual average for each of them). Also, the solar constant, which estimated fromth ground stations for beam solar radiations observations during the 20 century indicate coincidence with the phases of the 11- year cycles. It is known from sunspot observations (250 years) , and from C14 analysis, that there are another long-term cycles for the solar activity larger than 11-year cycle. The variability of the total solar irradiance affecting on the climate, and the Nile flooding, where there is a periodicities in the Nile flooding similar to that of solar activity, from the analysis of about 1300 years of the Nile level observations atth Cairo. The secular variations of the Nile levels, regularly measured from the 7 toth 15 century A.D., clearly correlate with the solar variations, which suggests evidence for solar influence on the climatic changes in the East African tropics The civilization of the ancient Egyptian was highly correlated with the Nile flooding , where the river Nile was and still yet, the source of the life in the Valley and Delta inside high dry desert area. The study depends on long -time historical data for Carbon 14 (more than five thousands years), and chronical scanning for all the elements of the ancient Egyptian civilization starting from the firs t dynasty to the twenty six dynasty. The result shows coincidence between the ancient Egyptian civilization and solar activity. For example, the period of pyramids building, which is one of the Brilliant periods, is corresponding to maximum solar activity, where the periods of occupation of Egypt by Foreign Peoples corresponding to minimum solar activity. The decline of the Kingdoms in ancient Egypt and occurrence of the intermediate periods are generally explained by very low Nile floods and prolonged droughts followed by severe famines and the destruction of the political structure. The study declear the role of solar activity on the climatic change, and the humankind history.

Dominance of climate warming effects on recent drying trends over wet monsoon regions

NASA Astrophysics Data System (ADS)

Park, Chang-Eui; Jeong, Su-Jong; Ho, Chang-Hoi; Park, Hoonyoung; Piao, Shilong; Kim, Jinwon; Feng, Song

2017-09-01

Understanding changes in background dryness over land is key information for adapting to climate change because of its critical socioeconomic consequences. However, causes of continental dryness changes remain uncertain because various climate parameters control dryness. Here, we verify dominant climate variables determining dryness trends over continental eastern Asia, which is characterized by diverse hydroclimate regimes ranging from arid to humid, by quantifying the relative effects of changes in precipitation, solar radiation, wind speed, surface air temperature, and relative humidity on trends in the aridity index based on observed data from 189 weather stations for the period of 1961-2010. Before the early 1980s (1961-1983), change in precipitation is a primary condition for determining aridity trends. In the later period (1984-2010), the dominant climate parameter for aridity trends varies according to the hydroclimate regime. Drying trends in arid regions are mostly explained by reduced precipitation. In contrast, the increase in potential evapotranspiration due to increased atmospheric water-holding capacity, a secondary impact of warming, works to increase aridity over the humid monsoon region despite an enhanced water supply and relatively less warming. Our results show significant drying effects of warming over the humid monsoon region in recent decades; this also supports the drying trends over warm and water-sufficient regions in future climate.

Effect of environmental dust particles on laser textured yttria-stabilized zirconia surface in humid air ambient

NASA Astrophysics Data System (ADS)

Yilbas, B. S.; Ali, H.; Al-Sharafi, A.; Al-Sulaiman, F.; Karatas, C.

2018-05-01

Zirconium nitride is used as a selective surface for concentrated solar heating applications and one of the methods to form a zirconium nitride is texturing of zirconia surface by a high intensity laser beam under high pressure nitrogen gas environment. Laser texturing also provides hydrophobic surface characteristics via forming micro/nano pillars at the surface; however, environmental dust settlement on textured surface influences the surface characteristics significantly. In the present study, laser texturing of zirconia surface and effects of the dust particles on the textured surface in a humid air ambient are investigated. Analytical tools are used to assess the morphological changes on the laser textured surface prior and after the dust settlement in the humid air ambient. It is found that laser textured surface has hydrophobic characteristics. The mud formed during condensate of water on the dust particles alters the characteristics of the laser textured surface. The tangential force required to remove the dry mud from the textured surface remains high; in which case, the dried liquid solution at the mud-textured surface interface is responsible for the strong adhesion of the dry mud on the textured surface. The textured surface becomes hydrophilic after the dry mud was removed from the surface by a desalinated water jet.

High Efficiency, Low Cost Solar Cells Manufactured Using 'Silicon Ink' on Thin Crystalline Silicon Wafers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Antoniadis, H.

Reported are the development and demonstration of a 17% efficient 25mm x 25mm crystalline Silicon solar cell and a 16% efficient 125mm x 125mm crystalline Silicon solar cell, both produced by Ink-jet printing Silicon Ink on a thin crystalline Silicon wafer. To achieve these objectives, processing approaches were developed to print the Silicon Ink in a predetermined pattern to form a high efficiency selective emitter, remove the solvents in the Silicon Ink and fuse the deposited particle Silicon films. Additionally, standard solar cell manufacturing equipment with slightly modified processes were used to complete the fabrication of the Silicon Ink highmore » efficiency solar cells. Also reported are the development and demonstration of a 18.5% efficient 125mm x 125mm monocrystalline Silicon cell, and a 17% efficient 125mm x 125mm multicrystalline Silicon cell, by utilizing high throughput Ink-jet and screen printing technologies. To achieve these objectives, Innovalight developed new high throughput processing tools to print and fuse both p and n type particle Silicon Inks in a predetermined pat-tern applied either on the front or the back of the cell. Additionally, a customized Ink-jet and screen printing systems, coupled with customized substrate handling solution, customized printing algorithms, and a customized ink drying process, in combination with a purchased turn-key line, were used to complete the high efficiency solar cells. This development work delivered a process capable of high volume producing 18.5% efficient crystalline Silicon solar cells and enabled the Innovalight to commercialize its technology by the summer of 2010.« less

Study of copper-free back contacts to thin film cadmium telluride solar cells

NASA Astrophysics Data System (ADS)

Viswanathan, Vijay

The goals of this project are to study Cu free back contact alternatives for CdS/CdTe thin film solar cells, and to research dry etching for CdTe surface preparation before contact application. In addition, an attempt has been made to evaluate the stability of some of the contacts researched. The contacts studied in this work include ZnTe/Cu2Te, Sb2Te 3, and Ni-P alloys. The ZnTe/Cu2Te contact system is studied as basically an extension of the earlier work done on Cu2Te at USF. RF sputtering from a compound target of ZnTe and Cu2Te respectively deposits these layers on etched CdTe surface. The effect of Cu2Te thickness and deposition temperature on contact and cell performance will be studied with the ZnTe depositions conditions kept constant. C-V measurements to study the effect of contact deposition conditions on CdTe doping will also be performed. These contacts will then be stressed to high temperatures (70--100°C) and their stability with stress time is analyzed. Sb2Te3 will be deposited on glass using RF sputtering, to study film properties with deposition temperature. The Sb2Te 3 contact performance will also be studied as a function of the Sb 2Te3 deposition temperature and thickness. The suitability of Ni-P alloys for back contacts to CdTe solar cells was studied by forming a colloidal mixture of Ni2P in graphite paste. The Ni-P contacts, painted on Br-methanol etched CdTe surface, will be studied as a function of Ni-P concentration (in the graphite paste), annealing temperature and time. Some of these cells will undergo temperature stress testing to determine contact behavior with time. Dry etching of CdTe will be studied as an alternative for wet etching processes currently used for CdTe solar cells. The CdTe surface is isotropically etched in a barrel reactor in N2, Ar or Ar:O 2 ambient. The effect of etching ambient, pressure, plasma power and etch time on contact performance will be studied.

Modeling the radiative effects of biomass burning aerosols on carbon fluxes in the Amazon region

NASA Astrophysics Data System (ADS)

Moreira, Demerval S.; Longo, Karla M.; Freitas, Saulo R.; Yamasoe, Marcia A.; Mercado, Lina M.; Rosário, Nilton E.; Gloor, Emauel; Viana, Rosane S. M.; Miller, John B.; Gatti, Luciana V.; Wiedemann, Kenia T.; Domingues, Lucas K. G.; Correia, Caio C. S.

2017-12-01

Every year, a dense smoke haze covers a large portion of South America originating from fires in the Amazon Basin and central parts of Brazil during the dry biomass burning season between August and October. Over a large portion of South America, the average aerosol optical depth at 550 nm exceeds 1.0 during the fire season, while the background value during the rainy season is below 0.2. Biomass burning aerosol particles increase scattering and absorption of the incident solar radiation. The regional-scale aerosol layer reduces the amount of solar energy reaching the surface, cools the near-surface air, and increases the diffuse radiation fraction over a large disturbed area of the Amazon rainforest. These factors affect the energy and CO2 fluxes at the surface. In this work, we applied a fully integrated atmospheric model to assess the impact of biomass burning aerosols in CO2 fluxes in the Amazon region during 2010. We address the effects of the attenuation of global solar radiation and the enhancement of the diffuse solar radiation flux inside the vegetation canopy. Our results indicate that biomass burning aerosols led to increases of about 27 % in the gross primary productivity of Amazonia and 10 % in plant respiration as well as a decline in soil respiration of 3 %. Consequently, in our model Amazonia became a net carbon sink; net ecosystem exchange during September 2010 dropped from +101 to -104 TgC when the aerosol effects are considered, mainly due to the aerosol diffuse radiation effect. For the forest biome, our results point to a dominance of the diffuse radiation effect on CO2 fluxes, reaching a balance of 50-50 % between the diffuse and direct aerosol effects for high aerosol loads. For C3 grasses and savanna (cerrado), as expected, the contribution of the diffuse radiation effect is much lower, tending to zero with the increase in aerosol load. Taking all biomes together, our model shows the Amazon during the dry season, in the presence of high biomass burning aerosol loads, changing from being a source to being a sink of CO2 to the atmosphere.

Achieving high performance polymer optoelectronic devices for high efficiency, long lifetime and low fabrication cost

NASA Astrophysics Data System (ADS)

Huang, Jinsong

This thesis described three types of organic optoelectronic devices: polymer light emitting diodes (PLED), polymer photovoltaic solar cell, and organic photo detector. The research in this work focuses improving their performance including device efficiency, operation lifetime simplifying fabrication process. With further understanding in PLED device physics, we come up new device operation model and improved device architecture design. This new method is closely related to understanding of the science and physics at organic/metal oxide and metal oxide/metal interface. In our new device design, both material and interface are considered in order to confine and balance all injected carriers, which has been demonstrated very be successful in increasing device efficiency. We created two world records in device efficiency: 18 lm/W for white emission fluorescence PLED, 22 lm/W for red emission phosphorescence PLED. Slow solvent drying process has been demonstrated to significantly increase device efficiency in poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C 61-butyric acid methyl ester (PCBM) mixture polymer solar cell. From the mobility study by time of flight, the increase of efficiency can be well correlated to the improved carrier transport property due to P3HT crystallization during slow solvent drying. And it is found that, similar to PLED, balanced carrier mobility is essential in high efficient polymer solar cell. There is also a revolution in our device fabrication method. A unique device fabrication method is presented by an electronic glue based lamination process combined with interface modification as a one-step polymer solar cell fabrication process. It can completely skip the thermal evaporation process, and benefit device lifetime by several merits: no air reactive. The device obtained is metal free, semi-transparent, flexible, self-encapsulated, and comparable efficiency with that by regular method. We found the photomultiplication (PM) phenomenon in C60 based device accidentally. The high PM factor makes it good candidate for photo detector. The high gain was assigned to the trapped-charge induced enhanced-injection at C60/PEDOT:PSS interface.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tang, Shuaiqi; Xie, Shaocheng; Zhang, Yunyan

This study describes the characteristics of large-scale vertical velocity, apparent heating source ( Q 1) and apparent moisture sink ( Q 2) profiles associated with seasonal and diurnal variations of convective systems observed during the two intensive operational periods (IOPs) that were conducted from 15 February to 26 March 2014 (wet season) and from 1 September to 10 October 2014 (dry season) near Manaus, Brazil, during the Green Ocean Amazon (GoAmazon2014/5) experiment. The derived large-scale fields have large diurnal variations according to convective activity in the GoAmazon region and the morning profiles show distinct differences between the dry and wetmore » seasons. In the wet season, propagating convective systems originating far from the GoAmazon region are often seen in the early morning, while in the dry season they are rarely observed. Afternoon convective systems due to solar heating are frequently seen in both seasons. Accordingly, in the morning, there is strong upward motion and associated heating and drying throughout the entire troposphere in the wet season, which is limited to lower levels in the dry season. In the afternoon, both seasons exhibit weak heating and strong moistening in the boundary layer related to the vertical convergence of eddy fluxes. Here, a set of case studies of three typical types of convective systems occurring in Amazonia – i.e., locally occurring systems, coastal-occurring systems and basin-occurring systems – is also conducted to investigate the variability of the large-scale environment with different types of convective systems.« less

Deposition parameterizations for the Industrial Source Complex (ISC3) model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wesely, Marvin L.; Doskey, Paul V.; Shannon, J. D.

2002-06-01

Improved algorithms have been developed to simulate the dry and wet deposition of hazardous air pollutants (HAPs) with the Industrial Source Complex version 3 (ISC3) model system. The dry deposition velocities (concentrations divided by downward flux at a specified height) of the gaseous HAPs are modeled with algorithms adapted from existing dry deposition modules. The dry deposition velocities are described in a conventional resistance scheme, for which micrometeorological formulas are applied to describe the aerodynamic resistances above the surface. Pathways to uptake at the ground and in vegetative canopies are depicted with several resistances that are affected by variations inmore » air temperature, humidity, solar irradiance, and soil moisture. The role of soil moisture variations in affecting the uptake of gases through vegetative plant leaf stomata is assessed with the relative available soil moisture, which is estimated with a rudimentary budget of soil moisture content. Some of the procedures and equations are simplified to be commensurate with the type and extent of information on atmospheric and surface conditions available to the ISC3 model system user. For example, standardized land use types and seasonal categories provide sets of resistances to uptake by various components of the surface. To describe the dry deposition of the large number of gaseous organic HAPS, a new technique based on laboratory study results and theoretical considerations has been developed providing a means of evaluating the role of lipid solubility in uptake by the waxy outer cuticle of vegetative plant leaves.« less

Primitive Fine-Grained Matrix in the Unequilbrated Enstatite Chondrites

NASA Technical Reports Server (NTRS)

Weisberg, M. K.; Zolensky, M. E.; Kimura, M.; Ebel, D. S.

2014-01-01

Enstatite chondrites (EC) have important implications for constraining conditions in the early solar system and for understanding the evolution of the Earth and other inner planets. They are among the most reduced solar system materials as reflected in their mineral compositions and assemblage. They are the only chondrites with oxygen as well as Cr, Ti, Ni and Zn stable isotope compositions similar to the earth and moon and most are completely dry, lacking any evidence of hydrous alteration; the only exception are EC clasts in the Kaidun breccia which have hydrous minerals. Thus, ECs likely formed within the snow line and are good candidates to be building blocks of the inner planets. Our goals are to provide a more detailed characterization the fine-grained matrix in E3 chondrites, understand its origin and relationship to chondrules, decipher the relationship between EH and EL chondrites and compare E3 matrix to matrices in C and O chondrites as well as other fine-grained solar system materials. Is E3 matrix the dust remaining from chondrule formation or a product of parent body processing or both?

Weather data for simplified energy calculation methods. Volume II. Middle United States: TRY data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Olsen, A.R.; Moreno, S.; Deringer, J.

1984-08-01

The objective of this report is to provide a source of weather data for direct use with a number of simplified energy calculation methods available today. Complete weather data for a number of cities in the United States are provided for use in the following methods: degree hour, modified degree hour, bin, modified bin, and variable degree day. This report contains sets of weather data for 22 cities in the continental United States using Test Reference Year (TRY) source weather data. The weather data at each city has been summarized in a number of ways to provide differing levels ofmore » detail necessary for alternative simplified energy calculation methods. Weather variables summarized include dry bulb and wet bulb temperature, percent relative humidity, humidity ratio, wind speed, percent possible sunshine, percent diffuse solar radiation, total solar radiation on horizontal and vertical surfaces, and solar heat gain through standard DSA glass. Monthly and annual summaries, in some cases by time of day, are available. These summaries are produced in a series of nine computer generated tables.« less

Nano-cones for broadband light coupling to high index substrates

NASA Astrophysics Data System (ADS)

Buencuerpo, J.; Torné, L.; Álvaro, R.; Llorens, J. M.; Dotor, M. L.; Ripalda, J. M.

2016-12-01

The moth-eye structure has been proposed several times as an antireflective coating to replace the standard optical thin films. Here, we experimentally demonstrate the feasibility of a dielectric moth-eye structure as an antireflective coating for high-index substrates, like GaAs. The fabricated photonic crystal has Si3N4 cones in a square lattice, sitting on top of a TiO2 index matching layer. This structure attains 1.4% of reflectance power losses in the operation spectral range of GaAs solar cells (440-870 nm), a 12.5% relative reduction of reflection power losses in comparison with a standard bilayer. The work presented here considers a fabrication process based on laser interference lithography and dry etching, which are compatible with solar cell devices. The experimental results are consistent with scattering matrix simulations of the fabricated structures. In a broader spectral range (400-1800 nm), the simulation estimates that the nanostructure also significantly outperforms the standard bilayer coating (3.1% vs. 4.5% reflection losses), a result of interest for multijunction tandem solar cells.

Large-scale use of solar energy with central receivers

NASA Astrophysics Data System (ADS)

Kreith, F.; Meyer, R. T.

1983-12-01

The working principles of solar central receiver power plants are outlined and applications are discussed. Heliostat arrays direct sunlight into a receiver cavity mounted on a tower, heating the working fluid in the tower to temperatures exceeding 500 C. The formulation for the image plane and the geometric concentration ratio for a heliostat field are provided, noting that commercial electric power plants will require concentration ratios of 200-1000. Automated controls consider imperfections in the mirrors, tracking errors, and seasonal insolation intensity and angular variations. Membranes may be used instead of rigid heliostat mirrors to reduce costs, while trade-offs exist between the efficiencies of cavity and exterior receivers on the tower. Sensible heat storage has proved most effective for cloudy or nighttime operations. Details of the DOE Solar One 10 MW plant, which began operation in 1982, are provided, with mention given to the 33.6 continuous hours of power generation that have been achieved. Projected costs of commercial installations are $700/kWt, and possible applications include recovering and refining oil, processing natural gas, uranium ore, and sugar cane, drying gypsum board, and manufacturing ammonia.

Effect of Non-fullerene Acceptors' Side Chains on the Morphology and Photovoltaic Performance of Organic Solar Cells.

PubMed

Zhang, Cai'e; Feng, Shiyu; Liu, Yahui; Hou, Ran; Zhang, Zhe; Xu, Xinjun; Wu, Youzhi; Bo, Zhishan

2017-10-04

Three indacenodithieno[3,2-b]thiophene (IT) cored small molecular acceptors (ITIC-SC6, ITIC-SC8, and ITIC-SC2C6) were synthesized, and the influence of side chains on their performances in solar cells was systematically probed. Our investigations have demonstrated the variation of side chains greatly affects the charge dissociation, charge mobility, and morphology of the donor:acceptor blend films. ITIC-SC2C6 with four branched side chains showed improved solubility, which can ensure the polymer donor to form favorable fibrous nanostructure during the drying of the blend film. Consequently, devices based on PBDB-ST:ITIC-SC2C6 demonstrated higher charge mobility, more effective exciton dissociation, and the optimal power conversion efficiency up to 9.16% with an FF of 0.63, a J sc of 15.81 mA cm -2 , and a V oc of 0.92 V. These results reveal that the side chain engineering is a valid way of tuning the morphology of blend films and further improving PCE in polymer solar cells.

Survey views of the Mir space station taken during rendezvous

NASA Image and Video Library

1997-01-16

STS081-709-061 (12-22 Jan. 1997) --- As recorded while Space Shuttle Atlantis was docked with Russia's Mir Space Station, this 70mm camera's frame shows South Africa's wine growing country (immediately right of the solar panel) in a southwest-looking perspective. Most of the population in the Western Cape Province, as it is known, is clustered in the wet extreme south of the country identified here with denser cloud masses. This is the Mediterranean region of the country, experiencing summer drought when the photograph was taken. Cape Town lies immediately right of the solar panel and the Swartland wheat country to the left. The darker green areas are more heavily vegetated regions on the continental escarpment. The large bay in the region is the remote St. Helena Bay (Africa's southernmost point, Cape Agulhas, lies behind the solar panel). The cloud-free parts of the country in the foreground is the sparsely populated semidesert known as the Karroo, a quiet region to which people retire both for its rare dry climate and its beauty.

Selecting elephant grass families and progenies to produce bioenergy through mixed models (REML/BLUP).

PubMed

Rodrigues, E V; Daher, R F; Dos Santos, A; Vivas, M; Machado, J C; Gravina, G do A; de Souza, Y P; Vidal, A K; Rocha, A Dos S; Freitas, R S

2017-05-18

Brazil has great potential to produce bioenergy since it is located in a tropical region that receives high incidence of solar energy and presents favorable climatic conditions for such purpose. However, the use of bioenergy in the country is below its productivity potential. The aim of the current study was to select full-sib progenies and families of elephant grass (Pennisetum purpureum S.) to optimize phenotypes relevant to bioenergy production through mixed models (REML/BLUP). The circulating diallel-based crossing of ten elephant grass genotypes was performed. An experimental design using the randomized block methodology, with three repetitions, was set to assess both the hybrids and the parents. Each plot comprised 14-m rows, 1.40 m spacing between rows, and 1.40 m spacing between plants. The number of tillers, plant height, culm diameter, fresh biomass production, dry biomass rate, and the dry biomass production were assessed. Genetic-statistical analyses were performed through mixed models (REML/BLUP). The genetic variance in the assessed families was explained through additive genetic effects and dominance genetic effects; the dominance variance was prevalent. Families such as Capim Cana D'África x Guaçu/I.Z.2, Cameroon x Cuba-115, CPAC x Cuba-115, Cameroon x Guaçu/I.Z.2, and IAC-Campinas x CPAC showed the highest dry biomass production. The family derived from the crossing between Cana D'África and Guaçu/I.Z.2 showed the largest number of potential individuals for traits such as plant height, culm diameter, fresh biomass production, dry biomass production, and dry biomass rate. The individual 5 in the family Cana D'África x Guaçu/I.Z.2, planted in blocks 1 and 2, showed the highest dry biomass production.

Large-scale vertical velocity, diabatic heating and drying profiles associated with seasonal and diurnal variations of convective systems observed in the GoAmazon2014/5 experiment

DOE PAGES

Tang, Shuaiqi; Xie, Shaocheng; Zhang, Yunyan; ...

2016-11-16

This study describes the characteristics of large-scale vertical velocity, apparent heating source ( Q 1) and apparent moisture sink ( Q 2) profiles associated with seasonal and diurnal variations of convective systems observed during the two intensive operational periods (IOPs) that were conducted from 15 February to 26 March 2014 (wet season) and from 1 September to 10 October 2014 (dry season) near Manaus, Brazil, during the Green Ocean Amazon (GoAmazon2014/5) experiment. The derived large-scale fields have large diurnal variations according to convective activity in the GoAmazon region and the morning profiles show distinct differences between the dry and wetmore » seasons. In the wet season, propagating convective systems originating far from the GoAmazon region are often seen in the early morning, while in the dry season they are rarely observed. Afternoon convective systems due to solar heating are frequently seen in both seasons. Accordingly, in the morning, there is strong upward motion and associated heating and drying throughout the entire troposphere in the wet season, which is limited to lower levels in the dry season. In the afternoon, both seasons exhibit weak heating and strong moistening in the boundary layer related to the vertical convergence of eddy fluxes. Here, a set of case studies of three typical types of convective systems occurring in Amazonia – i.e., locally occurring systems, coastal-occurring systems and basin-occurring systems – is also conducted to investigate the variability of the large-scale environment with different types of convective systems.« less

Large-scale vertical velocity, diabatic heating and drying profiles associated with seasonal and diurnal variations of convective systems observed in the GoAmazon2014/5 experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tang, Shuaiqi; Xie, Shaocheng; Zhang, Yunyan

2016-01-01

This study describes the characteristics of large-scale vertical velocity, apparent heating source ( Q 1) and apparent moisture sink ( Q 2) profiles associated with seasonal and diurnal variations of convective systems observed during the two intensive operational periods (IOPs) that were conducted from 15 February to 26 March 2014 (wet season) and from 1 September to 10 October 2014 (dry season) near Manaus, Brazil, during the Green Ocean Amazon (GoAmazon2014/5) experiment. The derived large-scale fields have large diurnal variations according to convective activity in the GoAmazon region and the morning profiles show distinct differences between the dry and wetmore » seasons. In the wet season, propagating convective systems originating far from the GoAmazon region are often seen in the early morning, while in the dry season they are rarely observed. Afternoon convective systems due to solar heating are frequently seen in both seasons. Accordingly, in the morning, there is strong upward motion and associated heating and drying throughout the entire troposphere in the wet season, which is limited to lower levels in the dry season. In the afternoon, both seasons exhibit weak heating and strong moistening in the boundary layer related to the vertical convergence of eddy fluxes. A set of case studies of three typical types of convective systems occurring in Amazonia – i.e., locally occurring systems, coastal-occurring systems and basin-occurring systems – is also conducted to investigate the variability of the large-scale environment with different types of convective systems.« less

Ternary semitransparent organic solar cells with a laminated top electrode

PubMed Central

Makha, Mohammed; Testa, Paolo; Anantharaman, Surendra Babu; Heier, Jakob; Jenatsch, Sandra; Leclaire, Nicolas; Tisserant, Jean-Nicolas; Véron, Anna C.; Wang, Lei; Nüesch, Frank; Hany, Roland

2017-01-01

Abstract Tinted and colour-neutral semitransparent organic photovoltaic elements are of interest for building-integrated applications in windows, on glass roofs or on facades. We demonstrate a semitransparent organic photovoltaic cell with a dry-laminated top electrode that achieves a uniform average visible transmittance of 51% and a power conversion efficiency of 3%. The photo-active material is based on a majority blend composed of a visibly absorbing donor polymer and a fullerene acceptor, to which a selective near-infrared absorbing cyanine dye is added as a minority component. Our results show that organic ternary blends are attractive for the fabrication of semitransparent solar cells in general, because a guest component with a complementary absorption can compensate for the inevitably reduced current generation capability of a high-performing binary blend when applied as a thin, semitransparent film. PMID:28179960

Ternary semitransparent organic solar cells with a laminated top electrode.

PubMed

Makha, Mohammed; Testa, Paolo; Anantharaman, Surendra Babu; Heier, Jakob; Jenatsch, Sandra; Leclaire, Nicolas; Tisserant, Jean-Nicolas; Véron, Anna C; Wang, Lei; Nüesch, Frank; Hany, Roland

2017-01-01

Tinted and colour-neutral semitransparent organic photovoltaic elements are of interest for building-integrated applications in windows, on glass roofs or on facades. We demonstrate a semitransparent organic photovoltaic cell with a dry-laminated top electrode that achieves a uniform average visible transmittance of 51% and a power conversion efficiency of 3%. The photo-active material is based on a majority blend composed of a visibly absorbing donor polymer and a fullerene acceptor, to which a selective near-infrared absorbing cyanine dye is added as a minority component. Our results show that organic ternary blends are attractive for the fabrication of semitransparent solar cells in general, because a guest component with a complementary absorption can compensate for the inevitably reduced current generation capability of a high-performing binary blend when applied as a thin, semitransparent film.

The Thermal Collector With Varied Glass Covers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luminosu, I.; Pop, N.

2010-08-04

The thermal collector with varied glass covers represents an innovation realized in order to build a collector able to reach the desired temperature by collecting the solar radiation from the smallest surface, with the highest efficiency. In the case of the thermal collector with variable cover glasses, the number of the glass plates covering the absorber increases together with the length of the circulation pipe for the working fluid. The thermal collector with varied glass covers compared to the conventional collector better meet user requirements because: for the same temperature increase, has the collecting area smaller; for the same collectionmore » area, realizes the highest temperature increase and has the highest efficiency. This works is addressed to researchers in the solar energy and to engineers responsible with air-conditioning systems design or industrial and agricultural products drying.« less

Ternary semitransparent organic solar cells with a laminated top electrode

NASA Astrophysics Data System (ADS)

Makha, Mohammed; Testa, Paolo; Anantharaman, Surendra Babu; Heier, Jakob; Jenatsch, Sandra; Leclaire, Nicolas; Tisserant, Jean-Nicolas; Véron, Anna C.; Wang, Lei; Nüesch, Frank; Hany, Roland

2017-12-01

Tinted and colour-neutral semitransparent organic photovoltaic elements are of interest for building-integrated applications in windows, on glass roofs or on facades. We demonstrate a semitransparent organic photovoltaic cell with a dry-laminated top electrode that achieves a uniform average visible transmittance of 51% and a power conversion efficiency of 3%. The photo-active material is based on a majority blend composed of a visibly absorbing donor polymer and a fullerene acceptor, to which a selective near-infrared absorbing cyanine dye is added as a minority component. Our results show that organic ternary blends are attractive for the fabrication of semitransparent solar cells in general, because a guest component with a complementary absorption can compensate for the inevitably reduced current generation capability of a high-performing binary blend when applied as a thin, semitransparent film.

Intercomparisons of high-resolution solar blind Raman lidar atmospheric profiles of water vapor with radiosondes and kytoon

NASA Technical Reports Server (NTRS)

Petri, K.; Salik, A.; Cooney, J.

1986-01-01

A report is given of measurements of atmospheric profiles of water vapor in the boundary layer by use of solar blind Raman lidar. These measurement episodes, occuring twice a day over a two week period, were accompanied by a dense net of supporting measurements. The support included two radiosonde launches per measurement episodes as well as a kytoon support measurement of water vapor using a wet bulb-dry bulb instrument. The kytoon strategy included ten minute stops at strategic altitudes. Additional kytoon measurements included ozone profiles and nephelometric extinction profiles in the visible. Typically, six or seven 1000 shot lidar profile averages were collected during a measurement episode. Overall performance comparisons are provided and intercomparisons between auxiliary measurement devices are presented. Data on the accuracy of the lidar water vapor profiles are presented.

Solar Urban Neighborhood (SUN). Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ellertson, J.

1984-07-10

The Solar Urban Neighborhood (SUN) project was conceived to demonstrate a widely applicable cooperative procedure for low and moderate income urban residents to conserve energy and promote neighborhood revitalization through installing affordable energy conservation and solar retrofit measures on their homes. The self-help retrofit systems demonstrated fan-assisted air panels for walls and a mansard roof as well as vented Trombe wall and a sunspace. Building upon a strong tradition of cooperation within their neighborhood (security watches, community gardening, bartering of skills for do-it-yourself projects), these Roxbury neighbors were able to use the DOE grant as a catalyst for doing amore » far more ambitious undertaking. Additionally, the project used elements of a private-public partnership since the project director was also an energy retrofit contractor with specialized equipment and skills to share, wholesale purchase access, etc. Countervailing negative forces which impeded the progress of the project were the very ambitiousness of the solar retrofit itself, the delays in receiving the initial start up grant advance and in overcoming zoning restrictions which required design modifications; and discovery of building defects (dry rot, carpenter ants) within the structures at the time of retrofit. Nevertheless, the SUN project did have a wide impact through formal and informal outreach; through an associated project, SUN-TECH, which promoted solar retrofit awareness and involvement of City of Boston building, energy, and housing officials; and through evolvement of a grass roots level public-private partnership.« less

Investigation of models for large-scale meteorological prediction experiments

NASA Technical Reports Server (NTRS)

Spar, J.

1981-01-01

An attempt is made to compute the contributions of various surface boundary conditions to the monthly mean states generated by the 7 layer, 8 x 10 GISS climate model (Hansen et al., 1980), and also to examine the influence of initial conditions on the model climate simulations. Obvious climatic controls as the shape and rotation of the Earth, the solar radiation, and the dry composition of the atmosphere are fixed, and only the surface boundary conditions are altered in the various climate simulations.

A new UV-A/B protecting pigment in the terrestrial cyanobacterium Nostoc commune

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scherer, S.; Chen, T.W.; Boeger, P.

1988-12-01

A new ultraviolet (UV)-A/B absorbing pigment with maxima at 312 and 330 nanometers from the cosmopolitan terrestrial cyanobacterium Nostoc commune is described. The pigment is found in high amounts (up to 10% of dry weight) in colonies grown under solar UV radiation but only in low concentrations in laboratory cultures illuminated by artificial light without UV. Its experimental induction by UV as well as its capacity to efficiently protect Nostoc against UV radiation is reported.

Responses to the 2800 years BP climatic oscillation in shallow- and deep-basin sediments from the Dead Sea

NASA Astrophysics Data System (ADS)

Neugebauer, Ina; Brauer, Achim; Schwab, Markus; Dulski, Peter; Frank, Ute; Hadzhiivanova, Elitsa; Kitagawa, Hiroyuki; Litt, Thomas; Schiebel, Vera; Taha, Nimer; Waldmann, Nicolas

2015-04-01

Laminated lake sediments from the Dead Sea basin provide high-resolution records of climatic variability in the eastern Mediterranean region, which is considered being especially sensitive to changing climatic conditions. In the study presented here, we aim to reconstruct palaeoclimatic changes and their relation to the frequency of flood/erosion and dust deposition events as archived in the Dead Sea basin for the time interval from ca 3700 to 1700 years BP. A ca 4 m thick, mostly annually laminated (varved) sediment section from the western margin of the Dead Sea (shallow-water DSEn - Ein Gedi profile) was analysed and correlated to the new ICDP Dead Sea Deep Drilling Project core 5017-1 from the deep basin. To detect even single event layers, we applied a multi-proxy approach of high-resolution microscopic thin section analyses, µXRF element scanning and magnetic susceptibility measurements, supported by grain size and palynological analyses. Based on radiocarbon and varve dating two pronounced dry periods were detected at ~3500-3300 yrs BP and ~2900-2400 yrs BP that are characterized by a sand deposit during the older dry period and enhanced frequency of coarse detrital layers during the younger dry period in the shallow-water DSEn core, both interpreted as increased erosion processes. In the 5017-1 deep-basin core these dry periods are depicted by halite deposits. The timing of the younger dry period broadly coincides with the Homeric Minimum of solar activity at ca 2800 yrs BP. Our results suggest that during this period the Dead Sea region experienced a change in synoptic weather patterns leading to an increased occurrence of flash-flood events, overprinting the overall dry climatic conditions. Following this dry spell, a 250-yrs period of increased dust deposition is observed, coinciding with more regular aragonite precipitation during less arid climatic conditions.

Solar tower enhanced natural draft dry cooling tower

NASA Astrophysics Data System (ADS)

Yang, Huiqiang; Xu, Yan; Acosta-Iborra, Alberto; Santana, Domingo

2017-06-01

Concentrating Solar Power (CSP) plants are located in desert areas where the Direct Normal Irradiance (DNI) value is very high. Since water resource is scarcely available, mechanical draft cooing technology is commonly used, with power consumption of mechanical fans being approximately 2% of the total power generated. Today, there is only one solar power plant (Khi Solar One in South Africa) uses a condenser installed in a Natural Draft Cooling (NDC) tower that avoids the windage loss of water occurring in wet cooling towers. Although, Khi Solar One is a cavity receiver power tower, the receivers can be hung onto the NDC tower. This paper looks at a novel integration of a NDC tower into an external molten salt receiver of a solar power plant, which is one of a largest commercial molten salt tower in China, with 100MWe power capacity. In this configuration study, the NDC tower surrounds the concrete tower of the receiver concentrically. In this way, the receiver concrete tower is the central support of the NDC tower, which consists of cable networks that are fixed to the concrete tower and suspended at a certain height over the floor. The cable networks support the shell of the NDC tower. To perform a preliminary analysis of the behavior of this novel configuration, two cases of numerical simulation in three dimensional (3D) models have been solved using the commercial Computational Fluid Dynamics (CFD) code, ANSYS Fluent 6.3. The results show that the integration of the NDC tower into an external central receiver tower is feasible. Additionally, the total heat transfer rate is not reduced but slightly increases when the molten salt receiver is in operation because of the additional natural draft induced by the high temperature of the receiver.

Production of sugarcane and tropical grasses as a renewable energy source. Second annual report, 1978-1979

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1979-01-01

Reseach continued on tropical grasses from Saccharum and related genera as sources of intensively-produced, solar-dried biomass. Categories of candidate grasses include short-, intermediate-, and long-rotation species. These categories are based on the time interval required for maximum dry matter production, and on future management requirements of energy crops for intensive co-production with food crop commodities. Year 1 studies at the greenhouse and field-plot levels were continued and broadened during Year 2. This included candidate screening, importation and quarantine of new clones, breeding, controlled nitrogen and water regimes, chemical growth control, tissue expansion and maturation control, seeding rates, harvest frequency, andmore » variable row spacing. Second-year studies were extended to the project's field-scale and mechanized-harvest phases. These include initial economic anayses for the short-rotation phases. These include initial economic analyses for the short-rotation category of candidate species.« less

The Genus Wallemia-From Contamination of Food to Health Threat.

PubMed

Zajc, Janja; Gunde-Cimerman, Nina

2018-05-21

The fungal genus Wallemia of the order Wallemiales (Wallemiomycotina, Basidiomycota) comprises the most xerotolerant, xerophilic and also halophilic species worldwide. Wallemia spp. are found in various osmotically challenged environments, such as dry, salted, or highly sugared foods, dry feed, hypersaline waters of solar salterns, salt crystals, indoor and outdoor air, and agriculture aerosols. Recently, eight species were recognized for the genus Wallemia , among which four are commonly associated with foods: W. sebi , W. mellicola , W. muriae and W. ichthyophaga . To date, only strains of W. sebi , W. mellicola and W. muriae have been reported to be related to human health problems, as either allergological conditions (e.g., farmer’s lung disease) or rare subcutaneous/cutaneous infections. Therefore, this allergological and infective potential, together with the toxins that the majority of Wallemia spp. produce even under saline conditions, defines these fungi as filamentous food-borne pathogenic fungi.

Development of a 500-Watt portable generator

NASA Astrophysics Data System (ADS)

Knochenhauer, Robert John

In many commercial and recreational environments where power is unavailable, there is a need for lightweight, efficient, reasonably priced and quiet power sources that can recharge batteries for various portable devices. The current benchmark device is the Honda EU1000i, a 1000-Watt (peak) generator that weighs only 29 pounds (dry) and has a respectable noise level of 59 dB (at 7 meters) under peak power loading. The intent of this thesis study is to focus on the thermal management of a novel generator design that develops peak power of 500-Watts, weighs in at less than 20 pounds (dry) and has a reasonably low noise level at peak power loading. Through the course of this assessment, two key lessons are learned: • Liquid cooling at this scale is possible, but not practical • Renewable power sources (wind turbines and/or solar panels) are viable alternatives when used in environments that offer suitable conditions.

Morphology Development in Solution-Processed Functional Organic Blend Films: An In Situ Viewpoint.

PubMed

Richter, Lee J; DeLongchamp, Dean M; Amassian, Aram

2017-05-10

Solution-processed organic films are a facile route to high-speed, low cost, large-area deposition of electrically functional components (transistors, solar cells, emitters, etc.) that can enable a diversity of emerging technologies, from Industry 4.0, to the Internet of things, to point-of-use heath care and elder care. The extreme sensitivity of the functional performance of organic films to structure and the general nonequilibrium nature of solution drying result in extreme processing-performance correlations. In this Review, we highlight insights into the fundamentals of solution-based film deposition afforded by recent state-of-the-art in situ measurements of functional film drying. Emphasis is placed on multimodal studies that combine surface-sensitive X-ray scattering (GIWAXS or GISAXS) with optical characterization to clearly define the evolution of solute structure (aggregation, crystallinity, and morphology) with film thickness.

Short-Term Environmental Effects and Their Influence on Spatial Homogeneity of Organic Solar Cell Functionality.

PubMed

Chien, Huei-Ting; Zach, Peter W; Friedel, Bettina

2017-08-23

In this study, we focus on the induced degradation and spatial inhomogeneity of organic photovoltaic devices under different environmental conditions, uncoupled from the influence of any auxiliary hole-transport (HT) layer. During testing of the corresponding devices comprising the standard photoactive layer of poly(3-hexylthiophene) as donor, blended with phenyl-C 61 -butyric acid methyl ester as acceptor, a comparison was made between the nonencapsulated devices upon exposure to argon in the dark, dry air in the dark, dry air with illumination, and humid air in the dark. The impact on the active layer's photophysics is discussed, along with the device physics in terms of integral solar cell performance and spatially resolved photocurrent distribution with point-to-point analysis of the diode characteristics to determine the origin of the observed integrated organic photovoltaic device behavior. The results show that even without the widely used hygroscopic HT layer, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate), humidity is still a major factor in the short-term environmental degradation of organic solar cells with this architecture, and not only oxygen or light, as is often reported. Different from previous reports where water-induced device degradation was spatially homogeneous and formation of Al 2 O 3 islands was only seen for oxygen permeation through pinholes in aluminum, we observed insulating islands merely after humidity exposure in the present study. Further, we demonstrated with laser beam induced current mapping and point-to-point diode analysis that the water-induced performance losses are a result of the exposed device area comprising regions with entirely unaltered high output and intact diode behavior and those with severe degradation showing detrimentally lowered output and voltage-independent charge blocking, which is essentially insulating behavior. It is suggested that this is caused by transport of water through pinholes to the organic/metal interface, where they form insulating oxide or hydroxide islands, while the organic active layer stays unharmed.

[Acumen function in leaves and its vertical distribution in a tropical rain forest of Costa Rica].

PubMed

Farji-Brener, Alejandro G; Valverde, Oscar; Paolini, Leonardo; de los Angeles La Torre, María; Quintero, Estela; Bonaccorso, Elisa; Arnedo, Luisa; Villalobos, Richard

2002-06-01

Water retention on the leaf surface can be maladaptive to the plant because it increases the colonization of epiphylls and interferes with the physiologic processes of the leaf, diminishing the photosynthetic capacity. To test if leaf driptips facilitate leaf drying after rainfall in a tropical rain forest of Costa Rica, we (1) experimentally measured the capacity to retain water on leaf surfaces of 30 plant species before and after driptip removal, and (2) analyzed the development of driptips along forest strata. We expected leaf driptips to be less developed in the upper strata due to the environmental conditions of the canopy (i.e., high solar radiation, strong winds and low relative humidity), which favor the natural drying of leaves. The presence of driptips increased 100% the water run off capacity of leaves in all the analyzed species. Also, the development of leaf driptips was smaller in canopy species than in understory species. Additionally, they became less developed in canopy species as trees increased in height. These results support the hypothesis that the adaptive role of driptips is to facilitate the drying of leaf surfaces.

MAVEN observations of the response of Mars to an interplanetary coronal mass ejection.

PubMed

Jakosky, B M; Grebowsky, J M; Luhmann, J G; Connerney, J; Eparvier, F; Ergun, R; Halekas, J; Larson, D; Mahaffy, P; McFadden, J; Mitchell, D F; Schneider, N; Zurek, R; Bougher, S; Brain, D; Ma, Y J; Mazelle, C; Andersson, L; Andrews, D; Baird, D; Baker, D; Bell, J M; Benna, M; Chaffin, M; Chamberlin, P; Chaufray, Y-Y; Clarke, J; Collinson, G; Combi, M; Crary, F; Cravens, T; Crismani, M; Curry, S; Curtis, D; Deighan, J; Delory, G; Dewey, R; DiBraccio, G; Dong, C; Dong, Y; Dunn, P; Elrod, M; England, S; Eriksson, A; Espley, J; Evans, S; Fang, X; Fillingim, M; Fortier, K; Fowler, C M; Fox, J; Gröller, H; Guzewich, S; Hara, T; Harada, Y; Holsclaw, G; Jain, S K; Jolitz, R; Leblanc, F; Lee, C O; Lee, Y; Lefevre, F; Lillis, R; Livi, R; Lo, D; Mayyasi, M; McClintock, W; McEnulty, T; Modolo, R; Montmessin, F; Morooka, M; Nagy, A; Olsen, K; Peterson, W; Rahmati, A; Ruhunusiri, S; Russell, C T; Sakai, S; Sauvaud, J-A; Seki, K; Steckiewicz, M; Stevens, M; Stewart, A I F; Stiepen, A; Stone, S; Tenishev, V; Thiemann, E; Tolson, R; Toublanc, D; Vogt, M; Weber, T; Withers, P; Woods, T; Yelle, R

2015-11-06

Coupling between the lower and upper atmosphere, combined with loss of gas from the upper atmosphere to space, likely contributed to the thin, cold, dry atmosphere of modern Mars. To help understand ongoing ion loss to space, the Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft made comprehensive measurements of the Mars upper atmosphere, ionosphere, and interactions with the Sun and solar wind during an interplanetary coronal mass ejection impact in March 2015. Responses include changes in the bow shock and magnetosheath, formation of widespread diffuse aurora, and enhancement of pick-up ions. Observations and models both show an enhancement in escape rate of ions to space during the event. Ion loss during solar events early in Mars history may have been a major contributor to the long-term evolution of the Mars atmosphere. Copyright © 2015, American Association for the Advancement of Science.

The effect of porous lead iodide precursor film on perovskite film formation and its photovoltaic property after an effective pretreatment

NASA Astrophysics Data System (ADS)

Yan, Jian-Jun; Li, Yan; Chang, Yin; Jiang, Pan; Wang, Cheng-Wei

2016-06-01

An effective solvent sealed natural drying (SND) pretreatment was introduced for forming a satisfactory crystalline porous iodide (PbI2) precursor film, which could help to generate excellent CH3NH3PbI3 perovskite films for high performance of planar heterojunction perovskite solar cells. And the influence of SND pretreated time on the device performance was investigated in detail. We found that the PbI2 precursor film after 10 min pretreatment could make the perovskite device achieve the optimal power conversion efficiency (PCE) of 8.6%, significantly increased up to 95.5% and 28.4% compared to without pretreatment or traditional treatment. The results show that the time of SND pretreatment is critical to forming large grain size and good crystallinity for PbI2 precursor film, which would markedly improve the efficiency of planar heterojunction perovskite solar cells.

Space Weather Storm Responses at Mars: Lessons from A Weakly Magnetized Terrestrial Planet

NASA Astrophysics Data System (ADS)

Luhmann, J. G.; Dong, C. F.; Ma, Y. J.; Curry, S. M.; Li, Yan; Lee, C. O.; Hara, T.; Lillis, R.; Halekas, J.; Connerney, J. E.; Espley, J.; Brain, D. A.; Dong, Y.; Jakosky, B. M.; Thiemann, E.; Eparvier, F.; Leblanc, F.; Withers, P.; Russell, C. T.

2017-10-01

Much can be learned from terrestrial planets that appear to have had the potential to be habitable, but failed to realize that potential. Mars shows evidence of a once hospitable surface environment. The reasons for its current state, and in particular its thin atmosphere and dry surface, are of great interest for what they can tell us about habitable zone planet outcomes. A main goal of the MAVEN mission is to observe Mars' atmosphere responses to solar and space weather influences, and in particular atmosphere escape related to space weather `storms' caused by interplanetary coronal mass ejections (ICMEs). Numerical experiments with a data-validated MHD model suggest how the effects of an observed moderately strong ICME compare to what happens during a more extreme event. The results suggest the kinds of solar and space weather conditions that can have evolutionary importance at a planet like Mars.

Solar and anthropogenic forcing of tropical hydrology

NASA Astrophysics Data System (ADS)

Shindell, Drew T.; Faluvegi, Greg; Miller, Ron L.; Schmidt, Gavin A.; Hansen, James E.; Sun, Shan

2006-12-01

Holocene climate proxies suggest substantial correlations between tropical meteorology and solar variations, but these have thus far not been explained. Using a coupled ocean-atmosphere-composition model forced by sustained multi-decadal irradiance increases, we show that greater tropical temperatures alter the hydrologic cycle, enhancing the climatological precipitation maxima in the tropics while drying the subtropical subsidence regions. The shift is enhanced by tropopause region ozone increases, and the model captures the pattern inferred from paleoclimate records. The physical process we describe likely affected past civilizations, including the Maya, Moche, and Ancestral Puebloans who experienced drought coincident with increased irradiance during the late medieval (~900-1250). Similarly, decreased irradiance may have affected cultures via a weakened monsoon during the Little Ice Age (~1400-1750). Projections of 21st-century climate change yield hydrologic cycle changes via similar processes, suggesting a strong likelihood of increased subtropical drought as climate warms.

Experimental and simulation studies on the effect of suction opening orientation on solar vertical chimney

NASA Astrophysics Data System (ADS)

Kumar, L. Madan Ananda; Sivaramakrishnan, V.; Premalatha, M.; Vivekanandan, M.

2017-07-01

The zero energy building considered is a single storey building in Tiruchirappalli city retrofitted with various green features. This study investigated the effect of a suction opening orientation on a vertical solar chimney (VSC), integrated into a one-storey building. It was designed, manufactured and tested through selection of different suction openings for the entry of air, including right, left, front, back, both right and left and both front and back sides. Genetic algorithm (GA) calculates maximum air flow rate for a building with VSC for better suction opening, in Tiruchirappalli's dry, environmental conditions. GA is a useful technique for finding an improved suction opening specifically in the presence of a host of independent parameters which are large. The obtained results are related to fluid flow temperature distribution along the chimney, mass flow rate and air change per hour. The findings between the GA and the experimental results show sound agreement.

Assessing solar energy and water use efficiencies in winter wheat

NASA Technical Reports Server (NTRS)

Asrar, G.; Hipps, L. E.; Kanemasu, E. T.

1982-01-01

The water use and solar energy conversion efficiencies of two cultivars of winter wheat (Triticum aestivum L., vars, Centurk and Newton) planted at three densities, were examined during a growing season. Water use, based on soil moisture depletion, was the lowest under the light, and the highest under the heavy planting densities of both cultivars. Water use efficiency of medium and heavy planting densities were greater than the light planting densities in both cultivars. The canopy radiation extinction coefficients of both cultivars increased with increases in planting density. Efficiency of operation interception of photosynthetically active radiation by both cultivars improved from the time of jointing until anthesis, and then decreased during senescence. The efficiency of the conversion of intercepted radiation to dry matter (biochemical efficiency) decreased throughout the growing season both cultivars. The interception, biochemical, and photosynthetic efficiencies improved as planting density increased.

Test Validation of the Repair to the Space Station Solar Alpha Rotary Joint

NASA Technical Reports Server (NTRS)

Allmon, Curtis; Wilkinson, Will; Loewenthal, Stu

2010-01-01

The Solar Array Alpha Joint Lubrication Interval Test (SARJ LITE) test rig was built as a method to evaluate the performance of the grease repair on the Starboard SARJ of the International Space Station (ISS) . The on-orbit SARJ was temporarily parked after receiving significant damage on one of its race ring surfaces as a result of inadequate lu brication (high dry contact friction) and unaccounted for roller traction kinematics. In a scaled down rig, flight-like roller bearings wer e preloaded and cycled on a nitrided 15-5 race surface. Grease was ad ded to the track and with instrumentation monitoring performance, trending data will be extracted and used to determine lubrication interva ls for both Port and Starboard ISS SARJ?s. The grease lubrication was found to be effective in eliminating the high friction that contributed to the onorbit race damage.

The effect of side-chain substitution and hot processing on diketopyrrolopyrrole-based polymers for organic solar cells.

PubMed

Heintges, Gaël H L; Leenaers, Pieter J; Janssen, René A J

2017-07-14

The effects of cold and hot processing on the performance of polymer-fullerene solar cells are investigated for diketopyrrolopyrrole (DPP) based polymers that were specifically designed and synthesized to exhibit a strong temperature-dependent aggregation in solution. The polymers, consisting of alternating DPP and oligothiophene units, are substituted with linear and second position branched alkyl side chains. For the polymer-fullerene blends that can be processed at room temperature, hot processing does not enhance the power conversion efficiencies compared to cold processing because the increased solubility at elevated temperatures results in the formation of wider polymer fibres that reduce charge generation. Instead, hot processing seems to be advantageous when cold processing is not possible due to a limited solubility at room temperature. The resulting morphologies are consistent with a nucleation-growth mechanism for polymer fibres during drying of the films.

Understanding perovskite formation through the intramolecular exchange method in ambient conditions

NASA Astrophysics Data System (ADS)

Szostak, Rodrigo; Castro, Jhon A. P.; Marques, Adriano S.; Nogueira, Ana F.

2017-04-01

Among the methods to prepare hybrid organic-inorganic perovskite films, the intramolecular exchange method was the first one that made possible to prepare perovskite solar cells with efficiencies higher than 20%. However, perovskite formation by this method is not completely understood, especially in ambient conditions. In this work, perovskite films were prepared by the intramolecular exchange method in ambient conditions. The spin coating speed and the frequency of the MAI solution dripping onto PbI2(DMSO) were varied during the deposition steps. With the combination of these two parameters, a rigid control of the solvent drying was possible. Thus, depending on the chosen conditions, the intermediate MAPb3I8·2DMSO was formed with residual PbI2. Otherwise, direct formation of perovskite film was attained. A mechanism for the direct formation of bulk perovskite was proposed. We also investigated how the posterior thermal annealing affects the crystallinity and defects in perovskite films. With prolonged thermal annealing, the excess of MAI can be avoided, increasing the efficiency and decreasing the hysteresis of the solar cells. The best perovskite solar cell achieved a stabilized power output of 12.9%. The findings of this work pave the way for realizing the fabrication of efficient perovskite solar cells in ambient atmosphere, a very desirable condition for cost-efficient large scale manufacturing of this technology.

Solar cycle activity and atmospheric dynamics revealed by Be-7

NASA Astrophysics Data System (ADS)

Kulan, A.; Aldahan, A.; Possnert, G.; Vintersved, I.

2003-04-01

In this study we present ^7Be and 137Cs concentrations in aerosols collected on surface air filters for the period 1972-2000 from three stations in Sweden covering latitudes 56^o to 70^o. The cosmogenic isotope ^7Be (T1/2 = 53.4 days) is produced by interaction of cosmic rays with the atmosphere. ^7Be is adsorbed onto aerosol particles after its formation, and removed from the atmosphere by both dry and wet deposition (atmospheric residence time of about one year). Maximum production of ^7Be occurs in the polar regions and the maximum deposition is found in the middle latitudes. After its production (mainly in the stratosphere) the ^7Be isotope is subjected to vertical and horizontal transport processes within the atmosphere and accordingly can act as a tracer of air mass origin and its approximate age. Furthermore, the production of cosmogenic isotopes is strongly influenced by the solar wind (solar activity, mainly energetic protons) and hence terrestrial records of ^7Be are directly reflecting the activity of the sun. Our ^7Be results reveal seasonal changes and together with the 137Cs records confirm a long-term transport and a strong coupling with air masses from middle and low latitudes. An apparent correlation between the 11-year solar cycle activity and ^7Be is found and we also observe that precipitation effectively depletes ^7Be from the atmosphere through washout of aerosols.

Late Holocene monsoon climate as evidenced by proxy records from a lacustrine sediment sequence in western Guangdong, South China

NASA Astrophysics Data System (ADS)

Zhong, Wei; Cao, jiayuan; Xue, Jibin; Ouyang, Jun; Tang, Xiaohong; Yin, Huanling; Liao, Congyun; Long, Kun

2014-02-01

The study of a 300-cm-thick exposed lacustrine sediment section in the Hedong village in Zhaoqing area which is located in sub-tropical west Guangdong Province in South China, demonstrates that the lacustrine sedimentary sequence possibly contains evidence for exploring variation of Asian monsoon climate. Multi-proxy records, including the humification intensity, total organic carbon, and grain size fractions, reveal a general trend towards dry and cold conditions in the late Holocene that this is because of a decrease in solar insolation on an orbital scale. Three intensified Asian summer monsoon (ASM) intervals (˜3300-3000 cal yr BP, ˜2600-1600 cal yr BP, and ˜900-600 cal yr BP), and three weakened ASM intervals (˜4000-3300 cal yr BP, ˜3000-2600 cal yr BP, and ˜1600-900 cal yr BP) are identified. Our humification record (HDcal) shows a good correlation on multi-centennial scale with the tree ring Δ14C record, a proxy of solar activity. A spectral analysis of HDcal reveals four significant cycles, i.e., ˜1250 yr, 300 yr, 110 yr, and 70 yr, and most of these cycles are related to the solar activity. Our findings indicate that solar output and oceanic-atmospheric circulation probably have influenced the late Holocene climate variability in the study region.

Stochastic modelling of temperatures affecting the in situ performance of a solar-assisted heat pump: The univariate approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Loveday, D.L.; Craggs, C.

Univariate stochastic modeling, using Box-Jenkins methods, is carried out for three air temperatures which can influence the performance of a solar-assisted heat pump system. In this system, external ambient air (the low grade source) is pre-heated by the conventional tiled roof of an occupied domestic residence. The air then crosses the evaporator of an electrically driven split heat pump which is situated in the roof space. Autocorrelation coefficients are presented for time series of the following dry-bulb temperatures: the external air, the residence internal (lounge) air, and the air in the roofspace after pre-heating but prior to crossing the heatmore » pump evaporator. Hourly data relating to a two-week period in the heating season was utilized, providing a 336-h dataset. Univariate models fitted to the first 300 observations were validated by forecasting ahead for the remaining 36 h in steps of 1 h. Comparison of forecasted and measured values showed good agreement, except for a 4-h period in which the intensity of solar radiation exceeded that which prevailed during the modeled period. It is concluded that the Box-Jenkins approach can be used to develop univariate mathematical models which adequately describe building and climate thermal behavior, and that the importance of solar radiation in this respect should not be overlooked.« less

Coping with heat: function of the natal coat of cape fur seal (Arctocephalus Pusillus Pusillus) pups in maintaining core body temperature.

PubMed

Erdsack, Nicola; Dehnhardt, Guido; Hanke, Wolf

2013-01-01

Cape fur seal (Arctocephalus pusillus) pups spend the first weeks of life exclusively or mainly ashore. They are exposed to intense solar radiation and high temperatures for long time periods, which results in temperatures up to at least 80°C on their black natal coat. To test the hypothesis that the natal coat has a crucial function in coping with these extreme conditions, we investigated the insulating properties of the natal coat in six captive newborn Cape fur seals during the first 50 days after birth. The natal fur differs from the adult fur not only in colour, but also in density, structure, and water repellence. We measured temperature on the fur surface and within the fur, as well as skin and rectal temperature under varying environmental conditions, comparable to the species' habitat. Experiments were designed to not influence the spontaneous behaviour of the pups. Rectal temperature was constant as long as the pups stayed dry, even during long-lasting intense solar radiation for up to 3 h. Skin temperature remained close to rectal temperature as long as the fur was dry, while with wet fur, skin temperature was significantly reduced as well. Our results show that the natal coat provides an effective insulation against overheating. The severely reduced insulation of wet natal fur against cold supports the assumption that the natal fur is an adaptation to the pups' terrestrial phase of life.

Coping with Heat: Function of The Natal Coat of Cape Fur Seal (Arctocephalus Pusillus Pusillus) Pups in Maintaining Core Body Temperature

PubMed Central

Erdsack, Nicola; Dehnhardt, Guido; Hanke, Wolf

2013-01-01

Cape fur seal (Arctocephalus pusillus) pups spend the first weeks of life exclusively or mainly ashore. They are exposed to intense solar radiation and high temperatures for long time periods, which results in temperatures up to at least 80°C on their black natal coat. To test the hypothesis that the natal coat has a crucial function in coping with these extreme conditions, we investigated the insulating properties of the natal coat in six captive newborn Cape fur seals during the first 50 days after birth. The natal fur differs from the adult fur not only in colour, but also in density, structure, and water repellence. We measured temperature on the fur surface and within the fur, as well as skin and rectal temperature under varying environmental conditions, comparable to the species' habitat. Experiments were designed to not influence the spontaneous behaviour of the pups. Rectal temperature was constant as long as the pups stayed dry, even during long-lasting intense solar radiation for up to 3 h. Skin temperature remained close to rectal temperature as long as the fur was dry, while with wet fur, skin temperature was significantly reduced as well. Our results show that the natal coat provides an effective insulation against overheating. The severely reduced insulation of wet natal fur against cold supports the assumption that the natal fur is an adaptation to the pups' terrestrial phase of life. PMID:23951287

An Assessment of Water Demand and Availability to meet Construction and Operational Needs for Large Utility-Scale Solar Projects in the Southwestern United States

NASA Astrophysics Data System (ADS)

Klise, G. T.; Tidwell, V. C.; Macknick, J.; Reno, M. D.; Moreland, B. D.; Zemlick, K. M.

2013-12-01

In the Southwestern United States, there are many large utility-scale solar photovoltaic (PV) and concentrating solar power (CSP) facilities currently in operation, with even more under construction and planned for future development. These are locations with high solar insolation and access to large metropolitan areas and existing grid infrastructure. The Bureau of Land Management, under a reasonably foreseeable development scenario, projects a total of almost 32 GW of installed utility-scale solar project capacity in the Southwest by 2030. To determine the potential impacts to water resources and the potential limitations water resources may have on development, we utilized methods outlined by the Bureau of Land Management (BLM) to determine potential water use in designated solar energy zones (SEZs) for construction and operations & maintenance (O&M), which is then evaluated according to water availability in six Southwestern states. Our results indicate that PV facilities overall use less water, however water for construction is high compared to lifetime operational water needs. There is a transition underway from wet cooled to dry cooled CSP facilities and larger PV facilities due to water use concerns, though some water is still necessary for construction, operations, and maintenance. Overall, ten watersheds, 9 in California, and one in New Mexico were identified as being of particular concern because of limited water availability. Understanding the location of potentially available water sources can help the solar industry determine locations that minimize impacts to existing water resources, and help understand potential costs when utilizing non-potable water sources or purchasing existing appropriated water. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Biomimetic artificial Si compound eye surface structures with broadband and wide-angle antireflection properties for Si-based optoelectronic applications

NASA Astrophysics Data System (ADS)

Leem, Jung Woo; Song, Young Min; Yu, Jae Su

2013-10-01

We report the biomimetic artificial silicon (Si) compound eye structures for broadband and wide-angle antireflection by integrating nanostructures (NSs) into periodically patterned microstructures (p-MSs) via thermal dewetting of gold and subsequent dry etching. The truncated cone microstructures with a two-dimensional hexagonal symmetry pattern were fabricated by photolithography and dry etching processes. The desirable shape and density of the nanostructures were obtained by controlled dewetting. The incorporation of p-MSs into the NS/Si surface further reduced the surface total reflectance over a wide wavelength range of 300-1030 nm at near normal incidence, indicating the average reflectance (Ravg) and solar weighted reflectance (RSWR) values of ~2.5% and 2%, respectively, compared to the only NSs on the flat Si surface (i.e., Ravg ~ 4.9% and RSWR ~ 4.5%). Additionally, the resulting structure improved the angle-dependent antireflection property due to its relatively omnidirectional shape, which exhibited the Ravg < 4.3% and RSWR < 3.7% in the wavelength region of 300-1100 nm even at a high incident light angle of 70° in the specular reflectance.We report the biomimetic artificial silicon (Si) compound eye structures for broadband and wide-angle antireflection by integrating nanostructures (NSs) into periodically patterned microstructures (p-MSs) via thermal dewetting of gold and subsequent dry etching. The truncated cone microstructures with a two-dimensional hexagonal symmetry pattern were fabricated by photolithography and dry etching processes. The desirable shape and density of the nanostructures were obtained by controlled dewetting. The incorporation of p-MSs into the NS/Si surface further reduced the surface total reflectance over a wide wavelength range of 300-1030 nm at near normal incidence, indicating the average reflectance (Ravg) and solar weighted reflectance (RSWR) values of ~2.5% and 2%, respectively, compared to the only NSs on the flat Si surface (i.e., Ravg ~ 4.9% and RSWR ~ 4.5%). Additionally, the resulting structure improved the angle-dependent antireflection property due to its relatively omnidirectional shape, which exhibited the Ravg < 4.3% and RSWR < 3.7% in the wavelength region of 300-1100 nm even at a high incident light angle of 70° in the specular reflectance. Electronic supplementary information (ESI) available: See DOI: 10.1039/c3nr02806b

A field study of the hemispherical directional reflectance factor and spectral albedo of dry snow

NASA Astrophysics Data System (ADS)

Bourgeois, C. S.; Calanca, P.; Ohmura, A.

2006-10-01

Hemispherical directional reflectance factors (HDRF) were collected under solar zenith angles from 49° to 85°. The experimental site was the Greenland Summit Environmental Observatory (72°35'N, 34°30'W, 3203 m above sea level) where both the snow and the atmosphere are very clean. The observations were carried out for two prevailing snow surface types: a smooth surface with wind-broken small snow grains and a surface covered with rime causing a higher surface roughness. A specially designed Gonio-Spectrometer (wavelength range 350-1050 nm), was developed at the Institute for Atmospheric and Climate Science and used to collect spectral HDRFs over the hemisphere. The angular step size was 15° in zenith and azimuth. The HDRFs showed strong variations ranging from 0.6 to 13, depending on the solar zenith angle. The HDRF distribution was nearly isotropic at noon. It varied with increasing solar zenith angle, resulting in a strong forward scattering peak. Smooth surfaces exhibited stronger forward scattering than surfaces covered with rime. At a solar zenith of 85°, an HDRF of ˜13 was observed in the forward scattering direction for λ=900 nm. Spectral albedos were calculated by interpolating the HDRF data sets on a 2° grid and integrating individual wavelengths. Spectral albedos showed variations depending on the solar illumination geometry and the snow surface properties. Broadband albedos were calculated by integration of the spectral albedos over all wavelengths. The broadband albedos derived from directional measurements reproduced the diurnal pattern measured with two back-to-back broadband pyranometers.

Atmospheric turbidity and transmittance of solar radiation in Riyadh, Saudi Arabia

NASA Astrophysics Data System (ADS)

El-Shobokshy, Mohammad S.; Al-Saedi, Yaseen G.

During the last two decades, the urban areas in the city of Riyadh—the capital of Saudi Arabia—were increasing at an exceptionally high rate through a series of development plans. The major plans had been completed by the end of 1982. Some other big utility projects were started and completed during 1987. As a consequence, the air quality has deteriorated markedly and air pollution episodes recorded during these activities showed that particulates were present in the atmosphere at high concentrations. Later in January 1991 the Gulf war started and the firing of the oil fields in Kuwait soon followed. It was estimated that soot particulates were emitted at a rate of 600 ton d -1 along with high rates of other gases. This event has led to significant air quality and visibility problems. Direct normal solar radiation has been measured during the summer months of July and August which were characterized by very dry and cloudless weather for the period between 1982 and 1992. A year-to-year trend of the transmittance of direct normal solar irradiance was then determined. The atmospheric fine aerosol (<2 μm diameter) loading data during the same period were used to establish a correlation between the aerosol concentration and the extinction coefficient. The total horizontal and direct normal solar radiation measurements during some days when the dark smoke emitted from the oil field fires in Kuwait were passing over Riyadh are presented. The reduction in solar irradiation reflects the intensity of dark smoke at a distance of 500 km from Kuwait.

Reactivation and reuse of TiO2-SnS2 composite catalyst for solar-driven water treatment.

PubMed

Kovacic, Marin; Kopcic, Nina; Kusic, Hrvoje; Stangar, Urska Lavrencic; Dionysiou, Dionysios D; Bozic, Ana Loncaric

2018-01-01

One of the most important features of photocatalytic materials intended to be used for water treatment is their long-term stability. The study is focused on the application of thermal and chemical treatments for the reactivation of TiO 2 -SnS 2 composite photocatalyst, prepared by hydrothermal synthesis and immobilized on the glass support using titania/silica binder. Such a catalytic system was applied in solar-driven treatment, solar/TiO 2 -SnS 2 /H 2 O 2 , for the purification of water contaminated with diclofenac (DCF). The effectiveness of studied reactivation methods for retaining TiO 2 -SnS 2 activity in consecutive cycles was evaluated on basis of DCF removal and conversion, and TOC removal and mineralization of organic content. Besides these water quality parameters, biodegradability changes in DCF aqueous solution treated by solar/TiO 2 -SnS 2 /H 2 O 2 process using simply reused (air-dried) and thermally and chemically reactivated composite photocatalyst through six consecutive cycles were monitored. It was established that both thermal and chemical reactivation retain TiO 2 -SnS 2 activity in the second cycle of its reuse. However, both treatments caused the alteration in the TiO 2 -SnS 2 morphology due to the partial transformation of visible-active SnS 2 into non-active SnO 2 . Such alteration, repeated through consecutive reactivation and reuse, was reflected through gradual activity loss of TiO 2 -SnS 2 composite in applied solar-driven water treatment.

Chapter 11: Concentrating Solar Power

DOE Office of Scientific and Technical Information (OSTI.GOV)

Turchi, Craig S; Stekli, J.; Bueno, P. C.

2017-01-02

This chapter summarizes the applications of the supercritical CO2 (sCO2) Brayton cycle in concentrating solar power (CSP) plants. The design and operation of CSP plants are reviewed to highlight the requirements for the power cycle and attributes that are advantageous for the solar-thermal application. The sCO2 Brayton cycle offers the potential of higher cycle efficiency versus superheated or supercritical steam cycles at temperatures relevant for CSP applications. In addition, Brayton cycle systems using sCO2 are anticipated to have smaller weight and volume, lower thermal mass, and less complex power blocks compared with Rankine cycles due to the higher density ofmore » the fluid and simpler cycle design. The simpler machinery and compact size of the sCO2 process may also reduce the installation, maintenance, and operation cost of the system. Power cycle capacities in the range of 10-150 MWe are anticipated for the CSP application. In this chapter, we explore sCO2 Brayton cycle configurations that have attributes that are desirable from the perspective of a CSP application, such as the ability to accommodate dry cooling and daily cycling, as well as integration with thermal energy storage.« less

A solar photovoltaic power system for use in Antarctica

NASA Astrophysics Data System (ADS)

Kohout, Lisa L.; Colozza, A. J.; Merolla, A.

A solar photovoltaic power system was designed and built at the NASA Lewis Research Center as part of the NASA/NSF Antarctic Space Analog Program. The system was installed at a remote field camp at Lake Hoare in the Dry Valleys and provided a six-person field team with the power to run personal computers and printers, lab equipment, lightning, and a small microwave oven. The system consists of three silicon photovoltaic sub-arrays delivering 1.5 kW peak power, three lead-acid gel battery modules supplying 2.4 kWh, and electrical distribution system which delivers 120 Vac and 12 Vdc to the user. The system was modularized for each of deployment and operation. Previously the camp has been powered by diesel generators, which have proven to be both noisy and polluting. The NSF, in an effort to reduce their dependence on diesel fuel from both and environmental and cost standpoint is interested in the use of alternate forms of energy, such as solar power. Such a power system will also provide NASA with important data on system level deployment and operation in a remote location by a minimally trained crew, as well as validate initial integration concepts.

A solar photovoltaic power system for use in Antarctica

NASA Astrophysics Data System (ADS)

Kohout, Lisa L.; Merolla, Anthony; Colozza, Anthony

1993-12-01

A solar photovoltaic power system was designed and built at the NASA Lewis Research Center as part of the NASA/NSF Antarctic Space Analog Program. The system was installed at a remote field camp at Lake Hoare in the Dry Valleys, and provided a six-person field team with electrical power for personal computers and printers, lab equipment, lighting, and a small microwave oven. The system consists of three silicon photovoltaic sub-arrays delivering a total of 1.5 kWe peak power, three lead-acid gel battery modules supplying 2.4 kWh, and an electrical distribution system which delivers 120 Vac and 12 Vdc to the user. The system was modularized for ease of deployment and operation. Previously the camp has been powered by diesel generators, which have proven to be both noisy and polluting. The NSF, in an effort to reduce their dependence on diesel fuel from both an environmental and cost standpoint, is interested in the use of alternate forms of energy, such as solar power. Such a power system also will provide NASA with important data on system level deployment and operation in a remote location by a minimally trained crew, as well as validate initial integration concepts.

A solar photovoltaic power system for use in Antarctica

NASA Technical Reports Server (NTRS)

Kohout, Lisa L.; Merolla, Anthony; Colozza, Anthony

1993-01-01

A solar photovoltaic power system was designed and built at the NASA Lewis Research Center as part of the NASA/NSF Antarctic Space Analog Program. The system was installed at a remote field camp at Lake Hoare in the Dry Valleys, and provided a six-person field team with electrical power for personal computers and printers, lab equipment, lighting, and a small microwave oven. The system consists of three silicon photovoltaic sub-arrays delivering a total of 1.5 kWe peak power, three lead-acid gel battery modules supplying 2.4 kWh, and an electrical distribution system which delivers 120 Vac and 12 Vdc to the user. The system was modularized for ease of deployment and operation. Previously the camp has been powered by diesel generators, which have proven to be both noisy and polluting. The NSF, in an effort to reduce their dependence on diesel fuel from both an environmental and cost standpoint, is interested in the use of alternate forms of energy, such as solar power. Such a power system also will provide NASA with important data on system level deployment and operation in a remote location by a minimally trained crew, as well as validate initial integration concepts.

A solar photovoltaic power system for use in Antarctica

NASA Technical Reports Server (NTRS)

Kohout, Lisa L.; Colozza, A. J.; Merolla, A.

1994-01-01

A solar photovoltaic power system was designed and built at the NASA Lewis Research Center as part of the NASA/NSF Antarctic Space Analog Program. The system was installed at a remote field camp at Lake Hoare in the Dry Valleys and provided a six-person field team with the power to run personal computers and printers, lab equipment, lightning, and a small microwave oven. The system consists of three silicon photovoltaic sub-arrays delivering 1.5 kW peak power, three lead-acid gel battery modules supplying 2.4 kWh, and electrical distribution system which delivers 120 Vac and 12 Vdc to the user. The system was modularized for each of deployment and operation. Previously the camp has been powered by diesel generators, which have proven to be both noisy and polluting. The NSF, in an effort to reduce their dependence on diesel fuel from both and environmental and cost standpoint is interested in the use of alternate forms of energy, such as solar power. Such a power system will also provide NASA with important data on system level deployment and operation in a remote location by a minimally trained crew, as well as validate initial integration concepts.

Weather data for simplified energy calculation methods. Volume IV. United States: WYEC data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Olsen, A.R.; Moreno, S.; Deringer, J.

The objective of this report is to provide a source of weather data for direct use with a number of simplified energy calculation methods available today. Complete weather data for a number of cities in the United States are provided for use in the following methods: degree hour, modified degree hour, bin, modified bin, and variable degree day. This report contains sets of weather data for 23 cities using Weather Year for Energy Calculations (WYEC) source weather data. Considerable overlap is present in cities (21) covered by both the TRY and WYEC data. The weather data at each city hasmore » been summarized in a number of ways to provide differing levels of detail necessary for alternative simplified energy calculation methods. Weather variables summarized include dry bulb and wet bulb temperature, percent relative humidity, humidity ratio, wind speed, percent possible sunshine, percent diffuse solar radiation, total solar radiation on horizontal and vertical surfaces, and solar heat gain through standard DSA glass. Monthly and annual summaries, in some cases by time of day, are available. These summaries are produced in a series of nine computer generated tables.« less

Incorporation of temperature and solar radiation thresholds to modify a lettuce downy mildew warning system.

PubMed

Wu, B M; van Bruggen, A H C; Subbarao, K V; Scherm, H

2002-06-01

ABSTRACT The effect of temperature on infection of lettuce by Bremia lactucae was investigated in controlled environment studies and in the field. In controlled conditions, lettuce seedlings inoculated with B. lactucae were incubated at 15, 20, 25, or 30 degrees C during a 4-h wet period immediately after inoculation or at the same temperatures during an 8-h dry period after the 4-h postinoculation wet period at 15 degrees C. High temperatures during wet and dry periods reduced subsequent disease incidence. Historical data from field studies in 1991 and 1992, in which days with or without infection had been identified, were analyzed by comparing average air temperatures during 0600 to 1000 and 1000 to 1400 Pacific standard time (PST) between the two groups of days. Days without infection had significantly higher temperatures (mean 21.4 degrees C) than days with infection (20.3 degrees C) during 1000 to 1400 PST (P < 0.01) but not during 0600 to 1000 PST. Therefore, temperature thresholds of 20 and 22 degrees C for the 3-h wet period after sunrise and the subsequent 4-h postpenetration period, respectively, were added to a previously developed disease warning system that predicts infection when morning leaf wetness lasts >/=4 h from 0600 PST. No infection was assumed to occur if average temperature during these periods exceeded the thresholds. Based on nonlinear regression and receiver operating characteristic curve analysis, the leaf wetness threshold of the previous warning system was also modified to >/=3-h leaf wetness (>/=0900 PST). Furthermore, by comparing solar radiation on days with infection and without infection, we determined that high solar radiation during 0500 to 0600 PST in conjunction with leaf wetness ending between 0900 and 1000 PST was associated with downy mildew infection. Therefore, instead of starting at 0600 PST, the calculation of the 3-h morning leaf wetness period was modified to start after sunrise, defined as the hour when measured solar radiation exceeded 8 W m(-2) (or 41 mumol m(-2) s(-1) for photon flux density). The modified warning system was compared with the previously developed system using historical weather and downy mildew data collected in coastal California. The modified system was more conservative when disease potential was high and recommended fewer fungicide applications when conditions were not conducive to downy mildew development.

Quarter-scale Model of Solar-powered Centurion Ultra-high-altitude Flying Wing in Flight during Firs

NASA Technical Reports Server (NTRS)

1997-01-01

Silhouetted under a bright blue sky, a quarter-scale model of the Centurion solar-powered flying wing shows off its long, narrow wing as it flies over the broad expanse of El Mirage Dry Lake in Southern California during a March 1997 test flight. Centurion was a unique remotely piloted, solar-powered airplane developed under NASA's Environmental Research Aircraft and Sensor (ERAST) Program at the Dryden Flight Research Center, Edwards, California. Dryden joined with AeroVironment, Inc., Monrovia, California, under an ERAST Joint Sponsored Research Agreement, to design, develop, manufacture, and conduct flight development tests for the Centurion. The airplane was believed to be the first aircraft designed to achieve sustained horizontal flight at altitudes of 90,000 to 100,000 feet. Achieving this capability would meet the ERAST goal of developing an ultrahigh-altitude airplane that could meet the needs of the science community to perform upper-atmosphere environmental data missions. Much of the technology leading to the Centurion was developed during the Pathfinder and Pathfinder-Plus projects. However, in the course of its development, the Centurion became a prototype technology demonstration aircraft designed to validate the technology for the Helios, a planned future high-altitude, solar-powered aircraft that could fly for weeks or months at a time on science or telecommunications missions. Centurion had 206-foot-long wings and used batteries to supply power to the craft's 14 electric motors and electronic systems. Centurion first flew at Dryden Nov. 10, 1998, and followed up with a second test flight Nov. 19. On its third and final flight on Dec. 3, the craft was aloft for 31 minutes and reached an altitude of about 400 feet. All three flights were conducted over a section of Rogers Dry Lake adjacent to Dryden. For its third flight, the Centurion carried a simulated payload of more than 600 pounds--almost half the lightweight aircraft's empty weight. John Del Frate, Dryden's project manager for solar-powered aircraft, said he was impressed to see how well the aircraft handled the large weight increase from an initial payload of 150 pounds to one of 600 pounds. During 1999, Centurion gave way to the Helios Prototype, the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions. This was an enlarged version of the Centurion flying wing with a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of the solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved its lifting capability. This allows the Helios Prototype to carry a regenerative fuel-cell-based energy storage system that will enable flight at night, while still meeting the performance goals originally established for the Centurion.

Quarter-scale Model of Solar-powered Centurion Ultra-high-altitude Flying Wing Landing during First

NASA Technical Reports Server (NTRS)

1997-01-01

A quarter-scale model of the future Centurion solar-powered high-altitude research aircraft settles in for landing after a March 1997 test flight at El Mirage Dry Lake, California. Centurion was a unique remotely piloted, solar-powered airplane developed under NASA's Environmental Research Aircraft and Sensor (ERAST) Program at the Dryden Flight Research Center, Edwards, California. Dryden joined with AeroVironment, Inc., Monrovia, California, under an ERAST Joint Sponsored Research Agreement, to design, develop, manufacture, and conduct flight development tests for the Centurion. The airplane was believed to be the first aircraft designed to achieve sustained horizontal flight at altitudes of 90,000 to 100,000 feet. Achieving this capability would meet the ERAST goal of developing an ultrahigh-altitude airplane that could meet the needs of the science community to perform upper-atmosphere environmental data missions. Much of the technology leading to the Centurion was developed during the Pathfinder and Pathfinder-Plus projects. However, in the course of its development, the Centurion became a prototype technology demonstration aircraft designed to validate the technology for the Helios, a planned future high-altitude, solar-powered aircraft that could fly for weeks or months at a time on science or telecommunications missions. Centurion had 206-foot-long wings and used batteries to supply power to the craft's 14 electric motors and electronic systems. Centurion first flew at Dryden Nov. 10, 1998, and followed up with a second test flight Nov. 19. On its third and final flight on Dec. 3, the craft was aloft for 31 minutes and reached an altitude of about 400 feet. All three flights were conducted over a section of Rogers Dry Lake adjacent to Dryden. For its third flight, the Centurion carried a simulated payload of more than 600 pounds--almost half the lightweight aircraft's empty weight. John Del Frate, Dryden's project manager for solar-powered aircraft, said he was impressed to see how well the aircraft handled the large weight increase from an initial payload of 150 pounds to one of 600 pounds. During 1999, Centurion gave way to the Helios Prototype, the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions. This was an enlarged version of the Centurion flying wing with a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of the solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved its lifting capability. This allows the Helios Prototype to carry a regenerative fuel-cell-based energy storage system that will enable flight at night, while still meeting the performance goals originally established for the Centurion.

Quarter-scale Model of Solar-powered Centurion Ultra-high-altitude Flying Wing in Flight during Firs

NASA Technical Reports Server (NTRS)

1997-01-01

With the snow-covered San Gabriel Mountains as a backdrop and a motorcycle-mounted chase crew alongside, a quarter-scale model of the Centurion solar-powered flying wing soars over El Mirage Dry Lake on an early test flight in March 1997. Centurion was a unique remotely piloted, solar-powered airplane developed under NASA's Environmental Research Aircraft and Sensor (ERAST) Program at the Dryden Flight Research Center, Edwards, California. Dryden joined with AeroVironment, Inc., Monrovia, California, under an ERAST Joint Sponsored Research Agreement, to design, develop, manufacture, and conduct flight development tests for the Centurion. The airplane was believed to be the first aircraft designed to achieve sustained horizontal flight at altitudes of 90,000 to 100,000 feet. Achieving this capability would meet the ERAST goal of developing an ultrahigh-altitude airplane that could meet the needs of the science community to perform upper-atmosphere environmental data missions. Much of the technology leading to the Centurion was developed during the Pathfinder and Pathfinder-Plus projects. However, in the course of its development, the Centurion became a prototype technology demonstration aircraft designed to validate the technology for the Helios, a planned future high-altitude, solar-powered aircraft that could fly for weeks or months at a time on science or telecommunications missions. Centurion had 206-foot-long wings and used batteries to supply power to the craft's 14 electric motors and electronic systems. Centurion first flew at Dryden Nov. 10, 1998, and followed up with a second test flight Nov. 19. On its third and final flight on Dec. 3, the craft was aloft for 31 minutes and reached an altitude of about 400 feet. All three flights were conducted over a section of Rogers Dry Lake adjacent to Dryden. For its third flight, the Centurion carried a simulated payload of more than 600 pounds--almost half the lightweight aircraft's empty weight. John Del Frate, Dryden's project manager for solar-powered aircraft, said he was impressed to see how well the aircraft handled the large weight increase from an initial payload of 150 pounds to one of 600 pounds. During 1999, Centurion gave way to the Helios Prototype, the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions. This was an enlarged version of the Centurion flying wing with a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of the solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved its lifting capability. This allows the Helios Prototype to carry a regenerative fuel-cell-based energy storage system that will enable flight at night, while still meeting the performance goals originally established for the Centurion.

Quarter-scale Model of Solar-powered Centurion Ultra-high-altitude Flying Wing in Flight during Firs

NASA Technical Reports Server (NTRS)

1997-01-01

Framed by wispy contrails left by passing jets high above, a quarter-scale model of the Centurion solar-electric flying wing shows off its graceful lines during a March 1997 test flight at El Mirage Dry Lake in California's Mojave Desert. Centurion was a unique remotely piloted, solar-powered airplane developed under NASA's Environmental Research Aircraft and Sensor (ERAST) Program at the Dryden Flight Research Center, Edwards, California. Dryden joined with AeroVironment, Inc., Monrovia, California, under an ERAST Joint Sponsored Research Agreement, to design, develop, manufacture, and conduct flight development tests for the Centurion. The airplane was believed to be the first aircraft designed to achieve sustained horizontal flight at altitudes of 90,000 to 100,000 feet. Achieving this capability would meet the ERAST goal of developing an ultrahigh-altitude airplane that could meet the needs of the science community to perform upper-atmosphere environmental data missions. Much of the technology leading to the Centurion was developed during the Pathfinder and Pathfinder-Plus projects. However, in the course of its development, the Centurion became a prototype technology demonstration aircraft designed to validate the technology for the Helios, a planned future high-altitude, solar-powered aircraft that could fly for weeks or months at a time on science or telecommunications missions. Centurion had 206-foot-long wings and used batteries to supply power to the craft's 14 electric motors and electronic systems. Centurion first flew at Dryden Nov. 10, 1998, and followed up with a second test flight Nov. 19. On its third and final flight on Dec. 3, the craft was aloft for 31 minutes and reached an altitude of about 400 feet. All three flights were conducted over a section of Rogers Dry Lake adjacent to Dryden. For its third flight, the Centurion carried a simulated payload of more than 600 pounds--almost half the lightweight aircraft's empty weight. John Del Frate, Dryden's project manager for solar-powered aircraft, said he was impressed to see how well the aircraft handled the large weight increase from an initial payload of 150 pounds to one of 600 pounds. During 1999, Centurion gave way to the Helios Prototype, the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions. This was an enlarged version of the Centurion flying wing with a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of the solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved its lifting capability. This allows the Helios Prototype to carry a regenerative fuel-cell-based energy storage system that will enable flight at night, while still meeting the performance goals originally established for the Centurion.

Quarter-scale Model of Solar-powered Centurion Ultra-high-altitude Flying Wing in Flight during Firs

NASA Technical Reports Server (NTRS)

1997-01-01

Trailed by a van carrying the remote pilot and observers, a radio-controlled quarter-scale model of the Centurion solar-electric flying wing makes a low pass over El Mirage Dry Lake in Southern California during a March 1997 test flight. Centurion was a unique remotely piloted, solar-powered airplane developed under NASA's Environmental Research Aircraft and Sensor (ERAST) Program at the Dryden Flight Research Center, Edwards, California. Dryden joined with AeroVironment, Inc., Monrovia, California, under an ERAST Joint Sponsored Research Agreement, to design, develop, manufacture, and conduct flight development tests for the Centurion. The airplane was believed to be the first aircraft designed to achieve sustained horizontal flight at altitudes of 90,000 to 100,000 feet. Achieving this capability would meet the ERAST goal of developing an ultrahigh-altitude airplane that could meet the needs of the science community to perform upper-atmosphere environmental data missions. Much of the technology leading to the Centurion was developed during the Pathfinder and Pathfinder-Plus projects. However, in the course of its development, the Centurion became a prototype technology demonstration aircraft designed to validate the technology for the Helios, a planned future high-altitude, solar-powered aircraft that could fly for weeks or months at a time on science or telecommunications missions. Centurion had 206-foot-long wings and used batteries to supply power to the craft's 14 electric motors and electronic systems. Centurion first flew at Dryden Nov. 10, 1998, and followed up with a second test flight Nov. 19. On its third and final flight on Dec. 3, the craft was aloft for 31 minutes and reached an altitude of about 400 feet. All three flights were conducted over a section of Rogers Dry Lake adjacent to Dryden. For its third flight, the Centurion carried a simulated payload of more than 600 pounds--almost half the lightweight aircraft's empty weight. John Del Frate, Dryden's project manager for solar-powered aircraft, said he was impressed to see how well the aircraft handled the large weight increase from an initial payload of 150 pounds to one of 600 pounds. During 1999, Centurion gave way to the Helios Prototype, the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions. This was an enlarged version of the Centurion flying wing with a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of the solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved its lifting capability. This allows the Helios Prototype to carry a regenerative fuel-cell-based energy storage system that will enable flight at night, while still meeting the performance goals originally established for the Centurion.

Quarter-scale Model of Solar-powered Centurion Ultra-high-altitude Flying Wing on Lakebed

NASA Technical Reports Server (NTRS)

1997-01-01

A quarter-scale model of the Centurion solar-powered flying wing rests on the clay of El Mirage Dry Lake in Southern California's high desert after completion of of a March 1997 flight test. Centurion was a unique remotely piloted, solar-powered airplane developed under NASA's Environmental Research Aircraft and Sensor (ERAST) Program at the Dryden Flight Research Center, Edwards, California. Dryden joined with AeroVironment, Inc., Monrovia, California, under an ERAST Joint Sponsored Research Agreement, to design, develop, manufacture, and conduct flight development tests for the Centurion. The airplane was believed to be the first aircraft designed to achieve sustained horizontal flight at altitudes of 90,000 to 100,000 feet. Achieving this capability would meet the ERAST goal of developing an ultrahigh-altitude airplane that could meet the needs of the science community to perform upper-atmosphere environmental data missions. Much of the technology leading to the Centurion was developed during the Pathfinder and Pathfinder-Plus projects. However, in the course of its development, the Centurion became a prototype technology demonstration aircraft designed to validate the technology for the Helios, a planned future high-altitude, solar-powered aircraft that could fly for weeks or months at a time on science or telecommunications missions. Centurion had 206-foot-long wings and used batteries to supply power to the craft's 14 electric motors and electronic systems. Centurion first flew at Dryden Nov. 10, 1998, and followed up with a second test flight Nov. 19. On its third and final flight on Dec. 3, the craft was aloft for 31 minutes and reached an altitude of about 400 feet. All three flights were conducted over a section of Rogers Dry Lake adjacent to Dryden. For its third flight, the Centurion carried a simulated payload of more than 600 pounds--almost half the lightweight aircraft's empty weight. John Del Frate, Dryden's project manager for solar-powered aircraft, said he was impressed to see how well the aircraft handled the large weight increase from an initial payload of 150 pounds to one of 600 pounds. During 1999, Centurion gave way to the Helios Prototype, the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions. This was an enlarged version of the Centurion flying wing with a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of the solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved its lifting capability. This allows the Helios Prototype to carry a regenerative fuel-cell-based energy storage system that will enable flight at night, while still meeting the performance goals originally established for the Centurion.

Quarter-scale Model of Solar-powered Centurion Ultra-high-altitude Flying Wing in Flight during Firs

NASA Technical Reports Server (NTRS)

1997-01-01

Silhouetted under a bright blue sky, a quarter-scale model of the Centurion solar-powered flying wing shows off its internal rib structure as it floats over the El Mirage Dry Lake in Southern California during a March 1997 test flight. Centurion was a unique remotely piloted, solar-powered airplane developed under NASA's Environmental Research Aircraft and Sensor (ERAST) Program at the Dryden Flight Research Center, Edwards, California. Dryden joined with AeroVironment, Inc., Monrovia, California, under an ERAST Joint Sponsored Research Agreement, to design, develop, manufacture, and conduct flight development tests for the Centurion. The airplane was believed to be the first aircraft designed to achieve sustained horizontal flight at altitudes of 90,000 to 100,000 feet. Achieving this capability would meet the ERAST goal of developing an ultrahigh-altitude airplane that could meet the needs of the science community to perform upper-atmosphere environmental data missions. Much of the technology leading to the Centurion was developed during the Pathfinder and Pathfinder-Plus projects. However, in the course of its development, the Centurion became a prototype technology demonstration aircraft designed to validate the technology for the Helios, a planned future high-altitude, solar-powered aircraft that could fly for weeks or months at a time on science or telecommunications missions. Centurion had 206-foot-long wings and used batteries to supply power to the craft's 14 electric motors and electronic systems. Centurion first flew at Dryden Nov. 10, 1998, and followed up with a second test flight Nov. 19. On its third and final flight on Dec. 3, the craft was aloft for 31 minutes and reached an altitude of about 400 feet. All three flights were conducted over a section of Rogers Dry Lake adjacent to Dryden. For its third flight, the Centurion carried a simulated payload of more than 600 pounds--almost half the lightweight aircraft's empty weight. John Del Frate, Dryden's project manager for solar-powered aircraft, said he was impressed to see how well the aircraft handled the large weight increase from an initial payload of 150 pounds to one of 600 pounds. During 1999, Centurion gave way to the Helios Prototype, the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions. This was an enlarged version of the Centurion flying wing with a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of the solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved its lifting capability. This allows the Helios Prototype to carry a regenerative fuel-cell-based energy storage system that will enable flight at night, while still meeting the performance goals originally established for the Centurion.

Quarter-scale Model of Solar-powered Centurion Ultra-high-altitude Flying Wing on Lakebed

NASA Technical Reports Server (NTRS)

1997-01-01

A quarter-scale model of the Centurion solar-powered flying wing rests on the clay of El Mirage Dry Lake in Southern California's high desert after completion of a March 1997 test flight. Centurion was a unique remotely piloted, solar-powered airplane developed under NASA's Environmental Research Aircraft and Sensor (ERAST) Program at the Dryden Flight Research Center, Edwards, California. Dryden joined with AeroVironment, Inc., Monrovia, California, under an ERAST Joint Sponsored Research Agreement, to design, develop, manufacture, and conduct flight development tests for the Centurion. The airplane was believed to be the first aircraft designed to achieve sustained horizontal flight at altitudes of 90,000 to 100,000 feet. Achieving this capability would meet the ERAST goal of developing an ultrahigh-altitude airplane that could meet the needs of the science community to perform upper-atmosphere environmental data missions. Much of the technology leading to the Centurion was developed during the Pathfinder and Pathfinder-Plus projects. However, in the course of its development, the Centurion became a prototype technology demonstration aircraft designed to validate the technology for the Helios, a planned future high-altitude, solar-powered aircraft that could fly for weeks or months at a time on science or telecommunications missions. Centurion had 206-foot-long wings and used batteries to supply power to the craft's 14 electric motors and electronic systems. Centurion first flew at Dryden Nov. 10, 1998, and followed up with a second test flight Nov. 19. On its third and final flight on Dec. 3, the craft was aloft for 31 minutes and reached an altitude of about 400 feet. All three flights were conducted over a section of Rogers Dry Lake adjacent to Dryden. For its third flight, the Centurion carried a simulated payload of more than 600 pounds--almost half the lightweight aircraft's empty weight. John Del Frate, Dryden's project manager for solar-powered aircraft, said he was impressed to see how well the aircraft handled the large weight increase from an initial payload of 150 pounds to one of 600 pounds. During 1999, Centurion gave way to the Helios Prototype, the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions. This was an enlarged version of the Centurion flying wing with a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of the solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved its lifting capability. This allows the Helios Prototype to carry a regenerative fuel-cell-based energy storage system that will enable flight at night, while still meeting the performance goals originally established for the Centurion.

Time-of-day effects of exposure to solar radiation on thermoregulation during outdoor exercise in the heat.

PubMed

Otani, Hidenori; Goto, Takayuki; Goto, Heita; Shirato, Minayuki

2017-01-01

High solar radiation has been recognised as a contributing factor to exertional heat-related illness in individuals exercising outdoors in the heat. Although solar radiation intensity has been known to have similar time-of-day variation as body temperature, the relationship between fluctuations in solar radiation associated with diurnal change in the angle of sunlight and thermoregulatory responses in individuals exercising outdoors in a hot environment remains largely unknown. The present study therefore investigated the time-of-day effects of variations in solar radiation associated with changing solar elevation angle on thermoregulatory responses during moderate-intensity outdoor exercise in the heat of summer. Eight healthy, high school baseball players, heat-acclimatised male volunteers completed a 3-h outdoor baseball trainings under the clear sky in the heat. The trainings were commenced at 0900 h in AM trial and at 1600 h in PM trial each on a separate day. Solar radiation and solar elevation angle during exercise continued to increase in AM (672-1107 W/m 2 and 44-69°) and decrease in PM (717-0 W/m 2 and 34-0°) and were higher on AM than on PM (both P < 0.001). Although ambient temperature (AM 32-36°C, PM 36-30°C) and wet-bulb globe temperature (AM 31-33°C, PM 34-27°C) also continued to increase in AM and decrease in PM, there were no differences between trials in these (both P > 0.05). Tympanic temperature measured by an infrared tympanic thermometer and mean skin temperature were higher in AM than PM at 120 and 180 min (P < 0.05). Skin temperature was higher in AM than PM at the upper arm and thigh at 120 min (P < 0.05) and at the calf at 120 and 180 min (both P < 0.05). Body heat gain from the sun was greater during exercise in AM than PM (P < 0.0001), at 0-60 min in PM than AM (P < 0.0001) and at 120-180 min in AM than PM (P < 0.0001). Dry heat loss during exercise was greater at 0-60 min (P < 0.0001), and lower at 60-120 min (P < 0.05) and 120-180 min (P < 0.0001) in AM than PM. Evaporative heat loss during exercise was greater in PM than AM at 120-180 min (P < 0.0001). Total (dry + evaporation) heat loss at the skin was greater during exercise in PM than AM (P < 0.0001), at 0-60 min in AM than PM (P < 0.0001) and at 60-120 and 120-180 min in PM than AM (P < 0.05 and 0.0001). Heart rate at 120-150 min was also higher in AM than PM (P < 0.05). Neither perceived thermal sensation nor rating of perceived exertion was different between trials (both P > 0.05). The current study demonstrates a greater thermoregulatory strain in the morning than in the afternoon resulting from a higher body temperature and heart rate in relation to an increase in environmental heat stress with rising solar radiation and solar elevation angle during moderate-intensity outdoor exercise in the heat. This response is associated with a lesser net heat loss at the skin and a greater body heat gain from the sun in the morning compared with the afternoon.

Water hyacinths for water quality improvement and biomass production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reddy, K.R.; Sutton, D.L.

The potential use of water hyacinth (Eichhornia crassipes (Mart.) Solms) for biomass production and for nutrient removal from waste waters is discussed. Warm climates in tropical and subtropical areas are conducive for establishing waste water treatment systems and biomass production farms with water hyacinth. Sources of nutrients available to culture water hyacinths include sewage effluent, agricultural drainage water, runoff from animal waste operations, methane digestor effluent, and water from eutrophic lakes and rivers. Growth rates of water hyacinths were found to be influenced by the nutrient composition of the water, plant density, solar radiation, and temperature. Annual yields of watermore » hyacinth biomass were found to range from 47 to 106 Mg dry wt ha/sup -1/ y/sup -1/, with approximately 50% of the biomass produced during May through August. A pond with a surface area of 2.65 ha and 1.0 m in depth containing 15 to 30 kg wet wt of water hyacinth per square meter (750-1500 g dry wt m/sup -2/) and a detention period of 7 d is adequate to treat 3785 m/sup 3/ d/sup -1/ (million gallons per day (mdg)) of sewage effluent. This hypothetical system would achieve 70 to 80% N removal, 40 to 50% P removal, and would produce a biomass yield of 690 to 1060 kg dry wt d/sup -1/ (13-20 g dry wt m/sup -2/ d/sup -1/). The biomass upon anaerobic digestion would yield 180 to 280 m/sup 3/ of methane/d. This is equivalent to 549 to 843 GJ ha/sup -1/ of energy from water hyacinth produced at a rate of 48 to 73 Mg dry wt ha/sup -1/ y/sup -1/.« less

El Niño Could Drive Intense Season for Amazon Fires

NASA Image and Video Library

2017-12-08

El Niño conditions in 2015 and early 2016 altered rainfall patterns around the world. In the Amazon, El Niño reduced rainfall during the wet season, leaving the region drier at the start of the 2016 dry season than any year since 2002, according to NASA satellite data. Wildfire risk for the dry season months of July to October this year now exceeds fire risk in 2005 and 2010, drought years when wildfires burned large areas of Amazon rainforest, said Doug Morton, an Earth scientist at NASA’s Goddard Space Flight Center who helped create the fire forecast. "Severe drought conditions at the start of the dry season set the stage for extreme fire risk in 2016 across the southern Amazon," Morton said. The Amazon fire forecast uses the relationship between climate and active fire detections from NASA satellites to predict fire season severity during the region’s dry season. Developed in 2011 by scientists at University of California, Irvine and NASA’s Goddard Space Flight Center, the forecast model is focused particularly on the link between sea surface temperatures and fire activity. Warmer sea surface temperatures in the tropical Pacific (El Niño) and Atlantic oceans shift rainfall away from the Amazon region, increasing the risk of fires during dry season months. Read more: go.nasa.gov/2937ADt NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Thermodynamics and Cloud Radiative Effect from the First Year of GoAmazon

NASA Technical Reports Server (NTRS)

Collow, Allie Marquardt; Miller, Mark; Trabachino, Lynne

2015-01-01

Deforestation is an ongoing concern for the Amazon Rainforest of Brazil and associated changes to the land surface have been hypothesized to alter the climate in the region. A comprehensive set of meteorological observations at the surface and within the lower troposphere above Manacapuru, Brazil and data from the Modern Era Retrospective Analysis for Research and Applications Version 2 (MERRA-2) are used to evaluate the seasonal cycle of cloudiness, thermodynamics, and the radiation budget. While ample moisture is present in the Amazon Rainforest year round, the northward progression of the Hadley circulation during the dry season contributes to a drying of the middle troposphere and inhibits the formation of deep convection. This results in a reduction in cloudiness and precipitation as well as an increase in the height of the lifting condensation level, which is shown to have a negative correlation to the fraction of low clouds. Frequent cloudiness prevents solar radiation from reaching the surface and clouds are often reflective with high values of shortwave cloud radiative effect at the surface and top of the atmosphere. Cloud radiative effect is reduced during the dry season however the dry season surface shortwave cloud radiative effect is still double what is observed during the wet season in other tropical locations. Within the column, the impact of clouds on the radiation budget is more prevalent in the longwave part of the spectrum, with a net warming in the wet season.

Toward Future Photovoltaic-Based Agriculture in Sea.

PubMed

Moustafa, Khaled

2016-04-01

To meet the challenges of climate change and water shortages, combining solar energy-based seawater desalination technologies with floating agriculture stations in one innovative hybrid system would be worthy of investigation for dry and sunny regions for seawater desalination and crop production within the same platform. Here, I discuss the feasibility of such a 'floating farm' or 'bluehouse' in the sea, by comparing it with the use of terrestrial greenhouses. I also debate the potential advantages and shortcomings of such a system. Copyright © 2015 Elsevier Ltd. All rights reserved.

Perennial Antarctic lake ice: an oasis for life in a polar desert

NASA Technical Reports Server (NTRS)

Priscu, J. C.; Fritsen, C. H.; Adams, E. E.; Giovannoni, S. J.; Paerl, H. W.; McKay, C. P.; Doran, P. T.; Gordon, D. A.; Lanoil, B. D.; Pinckney, J. L.

1998-01-01

The permanent ice covers of Antarctic lakes in the McMurdo Dry Valleys develop liquid water inclusions in response to solar heating of internal aeolian-derived sediments. The ice sediment particles serve as nutrient (inorganic and organic)-enriched microzones for the establishment of a physiologically and ecologically complex microbial consortium capable of contemporaneous photosynthesis, nitrogen fixation, and decomposition. The consortium is capable of physically and chemically establishing and modifying a relatively nutrient- and organic matter-enriched microbial "oasis" embedded in the lake ice cover.

Perennial Antarctic lake ice: an oasis for life in a polar desert.

PubMed

Priscu, J C; Fritsen, C H; Adams, E E; Giovannoni, S J; Paerl, H W; McKay, C P; Doran, P T; Gordon, D A; Lanoil, B D; Pinckney, J L

1998-06-26

The permanent ice covers of Antarctic lakes in the McMurdo Dry Valleys develop liquid water inclusions in response to solar heating of internal aeolian-derived sediments. The ice sediment particles serve as nutrient (inorganic and organic)-enriched microzones for the establishment of a physiologically and ecologically complex microbial consortium capable of contemporaneous photosynthesis, nitrogen fixation, and decomposition. The consortium is capable of physically and chemically establishing and modifying a relatively nutrient- and organic matter-enriched microbial "oasis" embedded in the lake ice cover.

Biomass production and nutrient removal potential of water hyacinth cultured in sewage effluent

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reddy, K.R.; Hueston, F.M.; McKinn, T.

1985-05-01

Growth and nutrient uptake of water hyacinth (Eichhornia crassipes (Mart Solms)) cultured in sewage effluent were measured over a period of one year in a prototype wastewater treatment system which has been in operation at Walt Disney World near Orlando, Florida. Annual productivity of water hyacinth cultured in primary sewage effluent (Channel II) was found to be in the range of 5 to 27 g dry wt/m/sup 2/ day (23.6 dry tons/acre yr). Average growth rate during the months of May through October 1982 for hyacinth cultured in Channel II (primary sewage effluent) and Channel I (treated primary sewage effluentmore » leaving Channel II) was about 16 g dry wt/m/sup 2/ (27 dry tons/acre yr), compared to the growth rate of 13 g dry wt/m/sup 2/ (22 dry tons/acre yr) for hyacinths cultured in secondary sewage effluent. Plants cultured in secondary sewage effluent generally had longer roots than the plants cultured in primary sewage effluent. A significant relationship was observed between the growth rate of hyacinth and the solar radiation. N and P concentration of the plant tissue were higher in the hyacinths cultured during winter months compared to the plants grown in summer months. Average N and P concentration of the plants cultured im primary sewage effluent were found to be 3.7% N and 0.94% P, respectively, while the plants cultured in secondary sewage effluent had a total N and P content of 2.8% N and 0.79% P. Nutrient ratios of the major plant nurtrients were found to be approximately the same as the nutrient ratios in the sewage effluent. Annual N and P uptake rates of hyacinth cultured in sewage effluent were found to be in the range of 1176 to 1193 kg N/ha yr and 321 to 387 kg P/ha yr, respectively.« less

Effects of dust accumulation and module cleaning on performance ratio of solar rooftop system and solar power plants

NASA Astrophysics Data System (ADS)

Sakarapunthip, Nattakarn; Chenvidhya, Dhirayut; Chuangchote, Surawut; Kirtikara, Krissanapong; Chenvidhya, Tanokkorn; Onreabroy, Wandee

2017-08-01

Thailand is an agricultural country, with rice, sugar, and cassava as the major export products. Production of rice, sugar cane, and cassava entails agricultural activities that give rise to significant airborne dusts. In this work, five photovoltaic (PV) units (one solar rooftop and four power plants) are selected for the study. From the study of dust accumulation on glass surface located near rice farms, it was found that opaque areas due to the deposition of dust are 11-14% after 1-2-week exposure. As a consequence, PV system performance is affected. Performance ratio was calculated to determine these effects. Overall results reveal that during the dry and hot seasons, dust deposition significantly affects the performance ratio. The performance ratio reduces by 1.6-3% for 1-month dust accumulation and reduces by 6-8% for 2-month dust accumulation. After cleaning the dust accumulated, the performance ratio greatly increases, resulting in the increase in the energy output by 10%. This increase provides economic and cost benefits of PV cleaning. The performance ratio is not significantly changed during the rainy season, which PV modules are relatively clean as the dust is washed away by rain. It was also found that most of the solar power plants in Thailand still rely on manual cleaning of PV modules with washing water followed by wiping. However, only one power plant, employs a machine for cleaning, resulting in lower cleaning costs.

Program to monitor and evaluate a passive solar greenhouse/aquaculture system. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1982-01-01

A temperature monitoring program of Amity's solar greenhouse demonstrated that air, soil, and water temperatures can be maintained at optimal levels without supplemental heat. A foil reflector placed in front of the greenhouse glazing at an angle of between 0 and 5/sup 0/ above horizontal enhanced direct light entering the greenhouse by as much as 22%. Aquaculture in the water heat storage of a solar greenhouse has been a success. Fish reached harvest size in about seven months. The two species that were received the best by the public were African perch (Tilapia mossambica) and channel catfish (Ictalurus punctatus). Althoughmore » carp (Cyprinus carpio) were the fastest growers they were not well received by the public. Linking hydroponics to greenhouse aquaculture shows a lot of promise. Different support medias were examined and tomatoes and European cucumbers were raised successfully. A savonius windmill was successfully linked to an aquaculture aeration system but because of the wind pattern in the Willamette valley the windmill system did not provide air in the evening when it was needed most. Alternate designs are discussed. Locally grown fish diets were evaluated for their ability to promote fish growth. Diets such as water hyacinth, duckweed, earthworms, beans, and comfrey were raised on the Amity site, pelleted with a hand grinder and solar dried. Duckweed and earthworms appear to hold promise for a nutritous, easy to grow and pelletize, food source. Amity's solar greenhouse, three coldframe designs and a PVC tunnel cloche were compared in a vegetable growing trial. Most impressive was the cloche design because it provided adequate protection, was inexpensive and very easy to build.« less

Variable fluorescence parameters in the filamentous Patagonian rhodophytes, Callithamnion gaudichaudii and Ceramium sp. under solar radiation.

PubMed

Häder, Donat-P; Lebert, Michael; Helbling, E Walter

2004-01-23

The filamentous rhodophytes Callithamnion gaudichaudi Agardh and Ceramium sp. were utilized to study the effects of solar radiation (PAR, 400-700 nm, UV-B, 280-315 nm and UV-A, 315-400 nm) on the photosynthetic performance in situ in Patagonia waters (Argentina). A pulse amplitude modulated (PAM) fluorometer was used to determine the fluorescence parameters. The two species grew in different habitats in the eulittoral: Ceramium sp. was found only in rock pools while C. gaudichaudii grew on exposed rocks and fell dry during low tide. Both species differed in their fluorescence parameters and their sensitivity to solar radiation exposure. The photosynthetic quantum yield had its lowest values at noon, but it recovered in the afternoon/evening hours, when irradiances were lower. PAR (irradiance of about 400 W m(-2) at noon) was responsible for most of the decrease in the yield on clear days, especially in Ceramium sp., but UVR (280-400 nm) also accounted for a significant decrease. Fluence rate response curves indicated that both species were adapted to low fluence rates and showed a pronounced non-photochemical quenching at intermediate and higher irradiances. Both species showed a rapid adaptation during measurement of fast induction kinetics but differed significantly in their fluorescence components. All photosynthetic pigments were bleached after 8 h exposure to solar radiation over a full day. Strong absorption in the UV-A range, most likely due to mycosporine-like amino acids, was detected in both strains. The pronounced sensitivity to solar radiation in situ and the recovery capacity of these two filamentous Rhodophyte species, as well as the presence of protective compounds, suggests that these algae have the ability to adapt to the relatively high radiation levels and changes in irradiance found in the Patagonia waters.

The SMART Ground-based Remote Sensing for Terra/MODIS Validation

NASA Technical Reports Server (NTRS)

Tsay, Si-Chee; Ji, Q. Jack; Barenbrug, M.; Lau, William K.-M. (Technical Monitor)

2001-01-01

A ground-based remote sensing system - SMART (Surface Measurements for Atmospheric Radiative Transfer) - was deployed during both the SAFARI-2000 and the ARREX-1999 dry season campaigns. The measurement site is the Skukuza airport. The operation period for 1999 is from August 16 to September 10. The main instruments include shortwave (approximately 0.28-2.8 micrometers) and longwave (approximately 4-50 micrometers) broadband radiometers, a shadow-band radiometer, a micro-pulse lidar, and a microwave radiometer. We also did some measurements of solar spectral flux by using an ASD spectrometer. The operation period for 2000 is from August 15 to September 22. This time we added a few new features to the SMART system: a solar tracker for direct and diffuse components of solar fluxes; the scanning capability to the microwave radiometer; a whole sky camera for documenting the sky conditions every minute; and a mini-weather station for atmospheric pressure, temperature, humidity, wind speed/direction. A surface SSFR (Solar Spectral Flux Radiometer) from NASA Ames also joined us for the measurements. This is a unique data set with reasonably long observational period and high accuracy. The data show good correlation with the local weather patterns. We also see diurnal change and some special events, such as fierce fires nearby. To quantify the surface radiative forcing of biomass burning aerosols, many pyranometers, pyrgeometers, and pyrheliometers measure the global, direct, and diffuse irradiance at the surface. These fluxes combining with the collocated optical thickness retrievals from sun photometer (or shadow-band radiometer), the solar radiative forcing, proportional to delta F/delta tau, can be investigated. Integrated with measurements of other instruments at the site, these data sets will serve as "ground truth" for the satellite measurements and modeling.

[Response of indica rice spikelet differentiation and degeneration to air temperature and solar radiation of different sowing dates].

PubMed

Wang, Ya Liang; Zhang, Yu Ping; Xiang, Jing; Wang, Lei; Chen, Hui Zhe; Zhang, Yi Kai; Zhang, Wen Qian; Zhu, De Feng

2017-11-01

In this study, three rice varieties, including three-line hybrid indica rice Wuyou308 and Tianyouhuazhan, and inbred indica rice Huanghuazhan were used to investigate the effects of air temperature and solar radiation on rice growth duration and spikelet differentiation and degeneration. Ten sowing-date treatments were conducted in this field experiment. The results showed that the growth duration of three indica rice varieties were more sensitive to air temperature than to day-length. With average temperature increase of 1 ℃, panicle initiation advanced 1.5 days, but the panicle growth duration had no significant correlation with the temperature and day-length. The number of spikelets and differentiated spikelets revealed significant differences among different sowing dates. Increases in average temperature, maximum temperature, minimum temperature, effective accumulated temperature, temperature gap and the solar radiation benefited dry matter accumulation and spikelet differentiation of all varieties. With increases of effective accumulated temperature, diurnal temperature gap and solar radiation by 50 ℃, 1 ℃, 50 MJ·m -2 during panicle initiation stage, the number of differentiated spikelets increased 10.5, 14.3, 17.1 respectively. The rate of degenerated spikelets had a quadratic correlation with air temperature, extreme high and low temperature aggravated spikelets degeneration, and low temperature stress made worse effect than high temperature stress. The rate of spikelet degeneration dramatically rose with the temperature falling below the critical temperature, the critical effective accumulated temperature, daily average temperature, daily maximum temperature and minimum temperature during panicle initiation were 550-600 ℃, 24.0-26.0 ℃, 32.0-34.0 ℃, 21.0-23.0 ℃, respectively. In practice, the natural condition of appropriate high temperature, large diurnal temperature gap and strong solar radiation were conducive to spikelet differentiation, and hindered the spikelet degeneration.

RDI's Wisdom Way Solar Village Final Report: Includes Utility Bill Analysis of Occupied Homes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robb Aldrich, Steven Winter Associates

2011-07-01

In 2010, Rural Development, Inc. (RDI) completed construction of Wisdom Way Solar Village (WWSV), a community of ten duplexes (20 homes) in Greenfield, MA. RDI was committed to very low energy use from the beginning of the design process throughout construction. Key features include: 1. Careful site plan so that all homes have solar access (for active and passive); 2. Cellulose insulation providing R-40 walls, R-50 ceiling, and R-40 floors; 3. Triple-pane windows; 4. Airtight construction (~0.1 CFM50/ft2 enclosure area); 5. Solar water heating systems with tankless, gas, auxiliary heaters; 6. PV systems (2.8 or 3.4kWSTC); 7. 2-4 bedrooms, 1,100-1,700more » ft2. The design heating loads in the homes were so small that each home is heated with a single, sealed-combustion, natural gas room heater. The cost savings from the simple HVAC systems made possible the tremendous investments in the homes' envelopes. The Consortium for Advanced Residential Buildings (CARB) monitored temperatures and comfort in several homes during the winter of 2009-2010. In the Spring of 2011, CARB obtained utility bill information from 13 occupied homes. Because of efficient lights, appliances, and conscientious home occupants, the energy generated by the solar electric systems exceeded the electric energy used in most homes. Most homes, in fact, had a net credit from the electric utility over the course of a year. On the natural gas side, total gas costs averaged $377 per year (for heating, water heating, cooking, and clothes drying). Total energy costs were even less - $337 per year, including all utility fees. The highest annual energy bill for any home evaluated was $458; the lowest was $171.« less

Soiling of building envelope surfaces and its effect on solar reflectance – Part II: Development of an accelerated aging method for roofing materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sleiman, Mohamad; Kirchstetter, Thomas W.; Berdahl, Paul

2014-01-09

Highly reflective roofs can decrease the energy required for building air conditioning, help mitigate the urban heat island effect, and slow global warming. However, these benefits are diminished by soiling and weathering processes that reduce the solar reflectance of most roofing materials. Soiling results from the deposition of atmospheric particulate matter and the growth of microorganisms, each of which absorb sunlight. Weathering of materials occurs with exposure to water, sunlight, and high temperatures. This study developed an accelerated aging method that incorporates features of soiling and weathering. The method sprays a calibrated aqueous soiling mixture of dust minerals, black carbon,more » humic acid, and salts onto preconditioned coupons of roofing materials, then subjects the soiled coupons to cycles of ultraviolet radiation, heat and water in a commercial weatherometer. Three soiling mixtures were optimized to reproduce the site-specific solar spectral reflectance features of roofing products exposed for 3 years in a hot and humid climate (Miami, Florida); a hot and dry climate (Phoenix, Arizona); and a polluted atmosphere in a temperate climate (Cleveland, Ohio). A fourth mixture was designed to reproduce the three-site average values of solar reflectance and thermal emittance attained after 3 years of natural exposure, which the Cool Roof Rating Council (CRRC) uses to rate roofing products sold in the US. This accelerated aging method was applied to 25 products₋single ply membranes, factory and field applied coatings, tiles, modified bitumen cap sheets, and asphalt shingles₋and reproduced in 3 days the CRRC's 3-year aged values of solar reflectance. In conclusion, this accelerated aging method can be used to speed the evaluation and rating of new cool roofing materials.« less

On dewetting of thin films due to crystallization (crystallization dewetting).

PubMed

Habibi, Mehran; Rahimzadeh, Amin; Eslamian, Morteza

2016-03-01

Drying and crystallization of a thin liquid film of an ionic or a similar solution can cause dewetting in the resulting thin solid film. This paper aims at investigating this type of dewetting, herein termed "crystallization dewetting", using PbI2 dissolved in organic solvents as the model solution. PbI2 solid films are usually used in X-ray detection and lead halide perovskite solar cells. In this work, PbI2 films are fabricated using spin coating and the effect of major parameters influencing the crystallization dewetting, including the type of the solvent, solution concentration, drying temperature, spin speed, as well as imposed vibration on the substrate are studied on dewetting, surface profile and coverage, using confocal scanning laser microscopy. Simplified hydrodynamic governing equations of crystallization in thin films are presented and using a mathematical representation of the process, it is phenomenologically demonstrated that crystallization dewetting occurs due to the absorption and consumption of the solution surrounding a growing crystal. Among the results, it is found that a low spin speed (high thickness), a high solution concentration and a low drying temperature promote crystal growth, and therefore crystallization dewetting. It is also shown that imposed vibration on the substrate can affect the crystal size and crystallization dewetting.

The energy balance on the surface of a tropical glacier tongue. Investigations on glacier Artesonraju, Cordillera Blanca, Perú.

NASA Astrophysics Data System (ADS)

Juen, I.; Mölg, T.; Wagnon, P.; Cullen, N. J.; Kaser, G.

2006-12-01

The Cordillera Blanca in Perú is situated in the Outer Tropics spanning from 8 to 10 ° South. Solar incidence and air temperature show only minor seasonal variations whereas precipitation occurs mainly from October to April. An energy balance station was installed on the tongue of glacier Artesonraju (4850 m a.s.l.) in March 2004. In this study each component of the energy balance on the glacier surface is analysed separately over a full year, covering one dry and one wet season. During the dry season glacier melt at the glacier tongue is app. 0.5 m we per month. In the wet season glacier melt is twice as much with 1 m we per month. This is due to higher energy fluxes and decreased sublimation during the wet season. With an energy balance model that has already been proved under tropical climate conditions (Mölg and Hardy, 2004) each energy flux is changed individually to evaluate the change in the amount of glacier melt. First results indicate that a change in humidity related variables affects glacier melt very differently in the dry and wet season, whereas a change in air temperature changes glacier melt more constantly throughout the year.

Efficacy and durability of ultraviolet tints in CR-39 ophthalmic lenses.

PubMed

Lee, D Y; Brown, W L; Trachimowicz, R

1997-11-01

Ocular protection from solar ultraviolet (UV) radiation has been emphasized in recent years as a result of the thinning of the ozone layer in the atmosphere. The purpose of this study was to evaluate the absorptive properties of UV tints in CR-39 lenses. We used a spectrophotometer to measure the UV transmittance of three groups of UV tinted CR-39 lenses, including (1) lenses tinted by local optical laboratories: (2) lenses tinted by us, using commercially available dyes: and (3) stock UV lenses that have UV absorptive molecules throughout the lens. We also tested the durability of these tints to daily washing/drying by measuring their UV transmittance characteristics at 3, 6, and 12 months. All the tested lenses absorbed all of the UV-B and at least 99% of UV-A. The durability of these UV tints when exposed to daily washing/drying was excellent: all lenses continued to absorb all of the UV-B and at least 99% of UV-A after 1 year. These data suggest that UV tinted CR-39 lenses provide protection against UV radiation that meets the ANSI Z80.3-1996 Standard for non-prescription sunglasses and fashion eyewear. Furthermore, normal daily washing/drying for 1 year does not cause a significant decrease in the protective effect of the UV tint.

Estimate of Radiosonde Dry Bias From Far-Infrared Measurements on the Antarctic Plateau

NASA Astrophysics Data System (ADS)

Rizzi, R.; Maestri, T.; Arosio, C.

2018-03-01

The experimental data set of downwelling radiance spectra measured at the ground in clear conditions during 2013 by a Far-Infrared Fourier Transform Spectrometer at Dome-C, Antarctica, presented in Rizzi et al. (2016, https://doi.org/10.1002/2016JD025341) is used to estimate the effect of solar heating of the radiosonde humidity sensor, called dry bias. The effect is quite evident comparing residuals for the austral summer and winter clear cases and can be modeled by an increase of the water vapor concentration at all levels by about 15%. Such an estimate has become possible only after a new version of the simulation code and spectroscopic data has become available, which has substantially improved the modeling of water vapor absorption in the far infrared. The negative yearly spectral bias reported in Rizzi et al. (2016, https://doi.org/10.1002/2016JD025341) is in fact greatly reduced when compared to the same measurement data set.

Multiseasonal and geobotanical approach in remote detection of greisenization areas in the Serra da Pedra Branca Granite, Goias State, Brazil

NASA Technical Reports Server (NTRS)

Parada, N. D. J. (Principal Investigator); Almeidafilho, R.

1983-01-01

Multiseasonal analysis of LANDSAT multispectral images in CCT format permitted the mapping of lithologic facies in the Pedra Branca Granite, using geobotanical associations, which occur in the form of variations in the density of cerrado vegetation, as well as the predominance of certain distinctive vegetation species. Dry season images did not show very good results in lithological differentiation due to anomalous illumination conditions related to the low solar elevation and the homogeneity in the vegetation cover, specially the grasses that become dry during this season. Rainy season image, on the other hand, allowed the separation of the lithological types, a fact that can be attributed to a greater differentiation among the geobotanical associations. As a result of this study, the muscovite-granite facies with greisenization zones, which are lithological indicators of important tin mineralization within the Serra da Pedra Branca Granite, were mapped. This methodology can be sucessfully applied to similar known granite bodies elsewhere in the Tin Province of Goias.

Large seasonal swings in leaf area of Amazon rainforests

PubMed Central

Myneni, Ranga B.; Yang, Wenze; Nemani, Ramakrishna R.; Huete, Alfredo R.; Dickinson, Robert E.; Knyazikhin, Yuri; Didan, Kamel; Fu, Rong; Negrón Juárez, Robinson I.; Saatchi, Sasan S.; Hashimoto, Hirofumi; Ichii, Kazuhito; Shabanov, Nikolay V.; Tan, Bin; Ratana, Piyachat; Privette, Jeffrey L.; Morisette, Jeffrey T.; Vermote, Eric F.; Roy, David P.; Wolfe, Robert E.; Friedl, Mark A.; Running, Steven W.; Votava, Petr; El-Saleous, Nazmi; Devadiga, Sadashiva; Su, Yin; Salomonson, Vincent V.

2007-01-01

Despite early speculation to the contrary, all tropical forests studied to date display seasonal variations in the presence of new leaves, flowers, and fruits. Past studies were focused on the timing of phenological events and their cues but not on the accompanying changes in leaf area that regulate vegetation–atmosphere exchanges of energy, momentum, and mass. Here we report, from analysis of 5 years of recent satellite data, seasonal swings in green leaf area of ≈25% in a majority of the Amazon rainforests. This seasonal cycle is timed to the seasonality of solar radiation in a manner that is suggestive of anticipatory and opportunistic patterns of net leaf flushing during the early to mid part of the light-rich dry season and net leaf abscission during the cloudy wet season. These seasonal swings in leaf area may be critical to initiation of the transition from dry to wet season, seasonal carbon balance between photosynthetic gains and respiratory losses, and litterfall nutrient cycling in moist tropical forests. PMID:17360360

Wave energy and intertidal productivity

PubMed Central

Leigh, Egbert G.; Paine, Robert T.; Quinn, James F.; Suchanek, Thomas H.

1987-01-01

In the northeastern Pacific, intertidal zones of the most wave-beaten shores receive more energy from breaking waves than from the sun. Despite severe mortality from winter storms, communities at some wave-beaten sites produce an extraordinary quantity of dry matter per unit area of shore per year. At wave-beaten sites of Tatoosh Island, WA, sea palms, Postelsia palmaeformis, can produce > 10 kg of dry matter, or 1.5 × 108 J, per m2 in a good year. Extraordinarily productive organisms such as Postelsia are restricted to wave-beaten sites. Intertidal organisms cannot transform wave energy into chemical energy, as photosynthetic plants transform solar energy, nor can intertidal organisms “harness” wave energy. Nonetheless, wave energy enhances the productivity of intertidal organisms. On exposed shores, waves increase the capacity of resident algae to acquire nutrients and use sunlight, augment the competitive ability of productive organisms, and protect intertidal residents by knocking away their enemies or preventing them from feeding. PMID:16593813

Multitemporal and geobotanical approach in the remote detection of Greisenization areas in the Serra da Pedra Branca Granite, Goias State, Brazil

NASA Technical Reports Server (NTRS)

Parada, N. D. J. (Principal Investigator); Filho, R. A.

1982-01-01

A multiseasonal analysis of LANDSAT multispectral images in CCT format permitted the mapping of lithologic facies in the Pedra Branca Granite, using geobotanical associations, which occur in the form of variations in the density of the cerrado vegetation, as well as the predominance of certain distinct vegetation species. Dry season images did not show very good results in lithological differentiation due to anomalous illumination conditions related to the low solar elevation and the homogeneity in the vegetation cover, specially the grass that becomes dry during this season. Rainy season images, on the other hand, allowed the separation of the lithological types, a fact that can be attributed to a greater differentiation among the geobotanical associations. The muscovite-granite facies with greisenization zones within the Serra da Pedra Branca were mapped. This methodology can be successfully applied to similar known granite bodies elsewhere in the Tin Province of Goias.

[Effects of cropping patterns on photosynthesis characteristics of summer maize and its utilization of solar and heat resources].

PubMed

Zhu, Yuan-Gang; Dong, Shu-Ting; Zhang, Ji-Wang; Liu, Peng; Yang, Jin-Sheng; Jia, Chun-Lan; Liu, Jing-Guo; Li, Deng-Hai

2010-06-01

In order to investigate the effects of interplanting and direct seeding on the photosynthesis characteristics of summer maize and its utilization of solar and heat resources, two summer maize cultivars (Zhengdan 958 and Denghai 661) were planted in the farmlands of Denghai Seed Co. Ltd in Laizhou City of Shandong Province, with 67500 plants x hm(-2) and three sowing dates. The above-ground biomass, plant growth rate, leaf area index, and net photosynthetic rate per ear leaf were measured to reveal the photosynthesis characteristics of test cultivars. In the meantime, the characters of grain-filling were simulated by Richards' model, and the solar resource utilization efficiency of the cultivars was calculated, in combining with meteorological data. Comparing with interplanting, direct seeding increased the grain yield by 1.17%-3.33%, but decreased the thousand-grain weight significantly. Growth stages were extended under earlier sowing. The leaf area index and net photosynthetic rate from flowering to 30 d after anthesis were significantly higher under direct seeding than under interplanting, but after then, they decreased faster. Direct seeding induced a higher accumulation of dry matter and a faster plant growth rate before and after flowering. Under direct seeding, the maximum grain-filling rate reached earlier, the starting potential was higher, but the grain-filling period, active grain-filling period, and W(max) were lower, compared with those under interplanting. Also under direct seeding, the total accumulative temperature and solar radiation during growth period decreased by 150-350 degrees C x d and 200-400 MJ x m(-2), respectively, but the solar resource utilization efficiency of grain increased by 10.5%-24.7%. All the results suggested that direct seeding was superior to interplanting for the summer maize production under field condition. In order to enhance solar and heat utilization efficiency and excavate yield potential, it would be essential to improve the leaf photosynthesis efficiency and postpone leaf aging.

Development of a selective thin film and of a hermetically sealed flat plate solar collector with gas filling

NASA Astrophysics Data System (ADS)

Zernial, W.

1982-12-01

The industrial productibility of a selective absorbing thin film was investigated on the basis of reactive cathodic sputtering of Ni. On substrates of 1.8 sq m of Al, Cu, steel and stainless steel, solar absorption values up to 97% were achieved at emissivities of 5 to 10%. A prototype flat plate collector for high temperatures with two covers and hermetical sealing was developed. The technical data of the collector were measured, dependent on the selectivity of the absorber, gas fillings of dry air, argon or SF6 and the geometry and were compared with those of an evacuated flat plate collector. A hermetical sealed double flat plate collector for low temperatures was developed which has the advantage of lower no load temperatures and higher energy gain for heating swimming pool water compared with a conventional flat plate collector. The insolation values on collectors were measured and were used for a calculation of the energy gains of different collector types.

Genesis Spacecraft Science Canister Preliminary Inspection and Cleaning

NASA Technical Reports Server (NTRS)

Hittle, J. D.; Calaway, M. J.; Allton, J. H.; Warren, J. L.; Schwartz, C. M.; Stansbery, E. K.

2006-01-01

The Genesis science canister is an aluminum cylinder (75 cm diameter and 35 cm tall) hinged at the mid-line for opening. This canister was cleaned and assembled in an ISO level 4 (Class 10) clean room at Johnson Space Center (JSC) prior to launch. The clean solar collectors were installed and the canister closed in the cleanroom to preserve collector cleanliness. The canister remained closed until opened on station at Earth-Sun L1 for solar wind collection. At the conclusion of collection, the canister was again closed to preserve collector cleanliness during Earth return and re-entry. Upon impacting the dry Utah lakebed at 300 kph the science canister integrity was breached. The canister was returned to JSC. The canister shell was briefly examined, imaged, gently cleaned of dust and packaged for storage in anticipation of future detailed examination. The condition of the science canister shell noted during this brief examination is presented here. The canister interior components were packaged and stored without imaging due to time constraints.

Vertically aligned single-walled carbon nanotubes as low-cost and high electrocatalytic counter electrode for dye-sensitized solar cells.

PubMed

Dong, Pei; Pint, Cary L; Hainey, Mel; Mirri, Francesca; Zhan, Yongjie; Zhang, Jing; Pasquali, Matteo; Hauge, Robert H; Verduzco, Rafael; Jiang, Mian; Lin, Hong; Lou, Jun

2011-08-01

A novel dye-sensitized solar cell (DSSC) structure using vertically aligned single-walled carbon nanotubes (VASWCNTs) as the counter electrode has been developed. In this design, the VASWCNTs serve as a stable high surface area and highly active electrocatalytic counter-electrode that could be a promising alternative to the conventional Pt analogue. Utilizing a scalable dry transfer approach to form a VASWCNTs conductive electrode, the DSSCs with various lengths of VASWCNTs were studied. VASWCNTs-DSSC with 34 μm original length was found to be the optimal choice in the present study. The highest conversion efficiencies of VASWCNTs-DSSC achieved 5.5%, which rivals that of the reference Pt DSSC. From the electrochemical impedance spectroscopy analysis, it shows that the new DSSC offers lower interface resistance between the electrolyte and the counter electrode. This reproducible work emphasizes the promise of VASWCNTs as efficient and stable counter electrode materials in DSSC device design, especially taking into account the low-cost merit of this promising material.

Enhanced power generation in concentrated photovoltaics using broadband antireflective coverglasses with moth eye structures.

PubMed

Song, Young Min; Jeong, Yonkil; Yeo, Chan Il; Lee, Yong Tak

2012-11-05

We present the effect of broadband antireflective coverglasses (BARCs) with moth eye structures on the power generation capability of a sub-receiver module for concentrated photovoltaics. The period and height of the moth eye structures were designed by a rigorous coupled-wave analysis method in order to cover the full solar spectral ranges without transmission band shrinkage. The BARCs with moth eye structures were prepared by the dry etching of silver (Ag) nanomasks, and the fabricated moth eye structures on coverglass showed strongly enhanced transmittance compared to the bare glass with a flat surface, at wavelengths of 300 - 1800 nm. The BARCs were mounted on InGaP/GaAs/Ge triple-junction solar cells and the power conversion efficiency of this sub-receiver module reached 42.16% for 196 suns, which is a 7.41% boosted value compared to that of a module with bare coverglass, without any detrimental changes of the open circuit voltages (V_oc) and fill factor (FF).

Enhanced power generation in concentrated photovoltaics using broadband antireflective coverglasses with moth eye structures.

PubMed

Song, Young Min; Jeong, Yonkil; Yeo, Chan Il; Lee, Yong Tak

2012-11-05

We present the effect of broadband antireflective coverglasses (BARCs) with moth eye structures on the power generation capability of a sub-receiver module for concentrated photovoltaics. The period and height of the moth eye structures were designed by a rigorous coupled-wave analysis method in order to cover the full solar spectral ranges without transmission band shrinkage. The BARCs with moth eye structures were prepared by the dry etching of silver (Ag) nanomasks, and the fabricated moth eye structures on coverglass showed strongly enhanced transmittance compared to the bare glass with a flat surface, at wavelengths of 300 - 1800 nm. The BARCs were mounted on InGaP/GaAs/Ge triple-junction solar cells and the power conversion efficiency of this sub-receiver module reached 42.16% for 196 suns, which is a 7.41% boosted value compared to that of a module with bare coverglass, without any detrimental changes of the open circuit voltages (V(oc)) and fill factor (FF).

Solar radiation and functional traits explain the decline of forest primary productivity along a tropical elevation gradient.

PubMed

Fyllas, Nikolaos M; Bentley, Lisa Patrick; Shenkin, Alexander; Asner, Gregory P; Atkin, Owen K; Díaz, Sandra; Enquist, Brian J; Farfan-Rios, William; Gloor, Emanuel; Guerrieri, Rossella; Huasco, Walter Huaraca; Ishida, Yoko; Martin, Roberta E; Meir, Patrick; Phillips, Oliver; Salinas, Norma; Silman, Miles; Weerasinghe, Lasantha K; Zaragoza-Castells, Joana; Malhi, Yadvinder

2017-06-01

One of the major challenges in ecology is to understand how ecosystems respond to changes in environmental conditions, and how taxonomic and functional diversity mediate these changes. In this study, we use a trait-spectra and individual-based model, to analyse variation in forest primary productivity along a 3.3 km elevation gradient in the Amazon-Andes. The model accurately predicted the magnitude and trends in forest productivity with elevation, with solar radiation and plant functional traits (leaf dry mass per area, leaf nitrogen and phosphorus concentration, and wood density) collectively accounting for productivity variation. Remarkably, explicit representation of temperature variation with elevation was not required to achieve accurate predictions of forest productivity, as trait variation driven by species turnover appears to capture the effect of temperature. Our semi-mechanistic model suggests that spatial variation in traits can potentially be used to estimate spatial variation in productivity at the landscape scale. © 2017 John Wiley & Sons Ltd/CNRS.

Significant Improvements in Pyranometer Nighttime Offsets Using High-Flow DC Ventilation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kutchenreiter, Mark; Michalski, J.J.; Long, C.N.

2017-05-22

Accurate solar radiation measurements using pyranometers are required to understand radiative impacts on the Earth's energy budget, solar energy production, and to validate radiative transfer models. Ventilators of pyranometers, which are used to keep the domes clean and dry, also affect instrument thermal offset accuracy. This poster presents a high-level overview of the ventilators for single-black-detector pyranometers and black-and-white pyranometers. For single-black-detector pyranometers with ventilators, high-flow-rate (50-CFM and higher), 12-V DC fans lower the offsets, lower the scatter, and improve the predictability of nighttime offsets compared to lower-flow-rate (35-CFM), 120-V AC fans operated in the same type of environmental setup.more » Black-and-white pyranometers, which are used to measure diffuse horizontal irradiance, sometimes show minor improvement with DC fan ventilation, but their offsets are always small, usually no more than 1 W/m2, whether AC- or DC-ventilated.« less

High resolution, low cost solar cell contact development. Quarterly technical progress and schedule report, September 28, 1980

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mardesich, N.

The scope of the contract covers the development and evaluation of forming solar cell collector grid contacts by the MIDFILM process. This is a proprietary process developed by the Ferro Corporation which is a subcontractor for the program. The MIDFILM process attains line resolution characteristics of photoresist methods with processing related to screen printing. The surface to be processed is first coated with a thin layer of photoresist material. Upon exposure to ultraviolet light through a suitable mask, the resist in the non-pattern area cross-links and becomes hard. The unexposed pattern areas remain tacky. The conductor material is applied inmore » the form of a dry mixture of metal and frit particles which adhere to the tacky pattern area. The assemblage is then fired to ash the photopolymer and sinter the fritted conductor powder. Effort was concentrated during this period on the establishment, optimization and identification of problem areas of the MIDFILM process. Progress is reported. (WHK)« less

Observed and modelled solar radiation components in sugarcane crop grown under tropical conditions

NASA Astrophysics Data System (ADS)

Santos, Marcos A. dos; Souza, José L. de; Lyra, Gustavo B.; Teodoro, Iêdo; Ferreira, Ricardo A.; Santos Almeida, Alexsandro C. dos; Lyra, Guilherme B.; Souza, Renan C. de; Lemes, Marco A. Maringolo

2017-04-01

The net radiation over vegetated surfaces is one of the major input variables in many models of soil evaporation, evapotranspiration as well as leaf wetness duration. In the literature there are relatively few studies on net radiation over sugarcane crop in tropical climates. The main objective of the present study was to assess the solar radiation components measured and modelled for two crop stages of a sugarcane crop in the region of Rio Largo, Alagoas, North-eastern Brazil. The measurements of the radiation components were made with a net radiometer during the dry and rainy seasons and two models were used to estimate net radiation: the Ortega-Farias model and the Monteith and Unsworth model. The highest values of net radiation were observed at the crop development stage, due mainly to the high indices of incoming solar radiation. The daily average albedos of sugarcane at the crop development and mid-season stages were 0.16 and 0.20, respectively. Both models showed a better fit for the crop development stage than for the mid-season stage. When they were inter-compared, Monteith and Unsworth model was more efficient than Ortega-Farias model, despite the dispersion of their simulated radiation components which was similar.

Spacecraft Mission Design for the Mitigation of the 2017 PDC Hypothetical Asteroid Threat

NASA Technical Reports Server (NTRS)

Barbee, Brent W.; Sarli, Bruno V.; Lyzhoft, Josh; Chodas, Paul W.; Englander, Jacob A.

2017-01-01

This paper presents a detailed mission design analysis results for the 2017 Planetary Defense Conference (PDC) Hypothetical Asteroid Impact Scenario, documented at https:cneos.jpl.nasa.govpdcspdc17. The mission design includes campaigns for both reconnaissance (flyby or rendezvous) of the asteroid (to characterize it and the nature of the threat it poses to Earth) and mitigation of the asteroid, via kinetic impactor deflection, nuclear explosive device (NED) deflection, or NED disruption. Relevant scenario parameters are varied to assess the sensitivity of the design outcome, such as asteroid bulk density, asteroid diameter, momentum enhancement factor, spacecraft launch vehicle, and mitigation system type. Different trajectory types are evaluated in the mission design process from purely ballistic to those involving optimal midcourse maneuvers, planetary gravity assists, and/or low-thrust solar electric propulsion. The trajectory optimization is targeted around peak deflection points that were found through a novel linear numerical technique method. The optimization process includes constrain parameters, such as Earth departure date, launch declination, spacecraft, asteroid relative velocity and solar phase angle, spacecraft dry mass, minimum/maximum spacecraft distances from Sun and Earth, and Earth-spacecraft communications line of sight. Results show that one of the best options for the 2017 PDC deflection is solar electric propelled rendezvous mission with a single spacecraft using NED for the deflection.

Direct drive options for electric propulsion systems

NASA Technical Reports Server (NTRS)

Hamley, John A.

1995-01-01

Power processing units (PPU's) in an electric propulsion system provide many challenging integration issues. The PPU must provide power to the electric thruster while maintaining compatibility with all of the spacecraft power and data systems. Inefficiencies in the power processor produce heat, which must be radiated to the environment in order to ensure reliable operation. Although PPU efficiencies are generally greater than 0.9, heat loads are often substantial. This heat must be rejected by thermal control systems which generally have specific masses of 15-30 kg/kW. PPU's also represent a large fraction of the electric propulsion system dry mass. Simplification or elimination of power processing in a propulsion system would reduce the electric propulsion system specific mass and improve the overall reliability and performance. A direct drive system would eliminate all or some of the power supplies required to operate a thruster by directly connecting the various thruster loads to the solar array. The development of concentrator solar arrays has enabled power bus voltages in excess of 300 V which is high enough for direct drive applications for Hall thrusters such as the Stationary Plasma Thruster (SPT). The option of solar array direct drive for SPT's is explored to provide a comparison between conventional and direct drive system mass.

Planet-B: A Japanese Mars aeronomy observer

NASA Technical Reports Server (NTRS)

Tsuruda, K.

1992-01-01

An introduction is given to a Japanese Mars mission (Planet-B) which is being planned at the Institute of Space and Aeronautical Science (ISAS), Japan. Planet-B aims to study the upper atmosphere of Mars and its interaction with the solar wind. The launch of Planet-B is planned for 1996 on a new launcher, M-L, which is being developed at ISAS. In addition to the interaction with the solar wind, the structure of the Martian upper atmosphere is thought to be controlled by the meteorological condition in the lower atmosphere. The orbit of Planet-B was chosen so that it will pass two important regions, the region where the solar wind interacts with the Martian upper atmosphere and the tail region where ion acceleration is taking place. Considering the drag due to the Martian atmosphere, the periapsis altitude of 150 km and apoapsis of 10 Martian radii are planned. The orbit plane will be nearly parallel to the ecliptic plane. The altitude of the spacecraft will be spin stabilized and its spin axis will be controlled to the point of the earth. The dry weight of the spacecraft will be about 250 kg, including the scientific payload which consists of a magnetometer, plasma instruments, HF sounder, UV imaging spectrometer, and lower atmosphere monitor.

Observed warming over northern South America has an anthropogenic origin

NASA Astrophysics Data System (ADS)

Barkhordarian, Armineh; von Storch, Hans; Zorita, Eduardo; Loikith, Paul C.; Mechoso, Carlos R.

2017-10-01

We investigate whether the recently observed trends in daily maximum and minimum near-surface air temperature (Tmax and Tmin, respectively) over South America (SA) are consistent with the simulated response of Tmin and Tmax to anthropogenic forcing. Results indicate that the recently observed warming in the dry seasons is well beyond the range of natural (internal) variability. In the wet season the natural modes of variability explain a substantial portion of Tmin and Tmax variability. We demonstrate that the large-scale component of greenhouse gas (GHG) forcing is detectable in dry-seasonal warming. However, none of the global and regional climate change projections reproduce the observed warming of up to 0.6 K/Decade in Tmax in 1983-2012 over northern SA during the austral spring (SON). Thus, besides the global manifestation of GHG forcing, other external drivers have an imprint. Using aerosols-only forcing simulations, our results provide evidence that anthropogenic aerosols also have a detectable influence in SON and that the indirect effect of aerosols on cloud's lifetime is more compatible with the observed record. In addition, there is an increasing trend in the observed incoming solar radiation over northern SA in SON, which is larger than expected from natural (internal) variability alone. We further show that in the dry seasons the spread of projected trends based on the RCP4.5 scenario derived from 30 CMIP5 models encompasses the observed area-averaged trends in Tmin and Tmax. This may imply that the observed excessive warming in the dry seasons serve as an illustration of plausible future expected change in the region.

A worldwide analysis of trends in water-balance evapotranspiration

NASA Astrophysics Data System (ADS)

Ukkola, A. M.; Prentice, I. C.

2013-05-01

Climate change is expected to alter the global hydrological cycle, with inevitable consequences for freshwater availability to people and ecosystems. But the attribution of recent trends in the terrestrial water balance remains disputed. This study attempts to account statistically for both trends and interannual variability in water-balance evapotranspiration (ET), estimated from the annual observed streamflow in 109 river basins during "water years" 1961-1999 and two gridded precipitation datasets. The basins were chosen based on the availability of streamflow time-series data in the Dai et al. (2009) synthesis. They were divided into water-limited "dry" and energy-limited "wet" basins following the Budyko framework. We investigated the potential roles of precipitation, aerosol-corrected solar radiation, land-use change, wind speed, air temperature, and atmospheric CO2. Both trends and variability in ET show strong control by precipitation. There is some additional control of ET trends by vegetation processes, but little evidence for control by other factors. Interannual variability in ET was overwhelmingly dominated by precipitation, which accounted on average for 52-54% of the variation in wet basins (ranging from 0 to 99%) and 84-85% in dry basins (ranging from 13 to 100%). Precipitation accounted for 39-42% of ET trends in wet basins and 69-79% in dry basins. Cropland expansion increased ET in dry basins. Net atmospheric CO2 effects on transpiration, estimated using the Land-surface Processes and eXchanges (LPX) model, did not contribute to observed trends in ET because declining stomatal conductance was counteracted by slightly but significantly increasing foliage cover.

Study on the benefits of using the date palm trees residuals in Saudi Arabia for development of the non-traditional wooden industry

NASA Astrophysics Data System (ADS)

Ghulman, H. A.; Metwally, M. Nabil; Alhazmi, M. W.

2017-02-01

The average world consumption of wood is about 22million tones/year (Faostat,2013), representing about 50% of the total world raw materials, which represents great challenge to find out alternative sources, and the agricultural residues can share strongly in this field. Important interest was paid to the palm trees residues, such as the "date palm leaves midrib" (DPLM), leaflets, coir and spadix stems, as DPLM after drying, which can be used as an industrial substitute of raw wooden materials particularly for the manufacture of particle boards. The Kingdom of Saudi-Arabia has the date palm trees as the third place in the world after Iran and Iraq, while Islamic and Arabic countries represent more than 92% of the world date palms. Local date palms increased from 17.5 million in 1995 to about 32 million in 2014, which may save about 15% of KSA wood imports (2.5 million tons costing about 5730 SR millions, saving about SR million 855/year according to 2014 prices), with 10 pruned &dried DPLMs /tree/year, if it is used only for particle board manufacture. The study includes a survey of the KSA wood imports; the dominant species of palms and their numbers, meteorological conditions, evaluation of DPLM drying rate in open air under the effect of solar radiation, achieving final moisture content of 8-12% in about 4 weeks. Also measurements of the mechanical properties of the dried Saudi DPLM samples approved the excellent mechanical properties as well as Beech and Spruce woods.

Effects of Varying Cloud Cover on Springtime Runoff in California's Sierra Nevada

NASA Astrophysics Data System (ADS)

Sumargo, E.; Cayan, D. R.

2017-12-01

This study investigates how cloud cover modifies snowmelt-runoff processes in Sierra Nevada watersheds during dry and wet periods. We use two of the California Department of Water Resources' (DWR's) quasi-operational models of the Tuolumne and Merced River basins developed from the USGS Precipitation-Runoff Modeling System (PRMS) hydrologic modeling system. Model simulations are conducted after a validated optimization of model performance in simulating recent (1996-2014) historical variability in the Tuolumne and Merced basins using solar radiation (Qsi) derived from Geostationary Operational Environmental Satellite (GOES) remote sensing. Specifically, the questions we address are: 1) how sensitive are snowmelt and runoff in the Tuolumne and Merced River basins to Qsi variability associated with cloud cover variations?, and 2) does this sensitivity change in dry vs. wet years? To address these question, we conduct two experiments, where: E1) theoretical clear-sky Qsi is used as an input to PRMS, and E2) the annual harmonic cycle of Qsi is used as an input to PRMS. The resulting hydrographs from these experiments exhibit changes in peak streamflow timing by several days to a few weeks and smaller streamflow variability when compared to the actual flows and the original simulations. For E1, despite some variations, this pattern persists when the result is evaluated for dry-year and wet-year subsets, reflecting the consistently higher Qsi input available. For E2, the hydrograph shows a later spring-summer streamflow peak in the dry-year subset when compared to the original simulations, indicating the relative importance of the modulating effect of cloud cover on snowmelt-runoff in drier years.

Optimal cooling strategies for players in Australian Tennis Open conditions.

PubMed

Lynch, Grant P; Périard, Julien D; Pluim, Babette M; Brotherhood, John R; Jay, Ollie

2018-03-01

We compared the utility of four cooling interventions for reducing heat strain during simulated tennis match-play in an environment representative of the peak conditions possible at the Australian Open (45°C, <10% RH, 475W/m 2 solar radiation). Nine trained males undertook four trials in a climate chamber, each time completing 4 sets of simulated match-play. During ITF-mandated breaks (90-s between odd-numbered games; 120-s between sets), either iced towels (ICE), an electric fan (FAN dry ), a fan with moisture applied to the skin (FAN wet ), or ad libitum 10°C water ingestion only (CON) was administered. Rectal temperature (T re ), mean skin temperature (T sk ), heart rate (HR), thermal sensation (TS), perceived exertion (RPE) and whole body sweating (WBSR) were measured. After set 3, T re was lower in ICE (38.2±0.3°C) compared to FAN dry (38.7±0.5°C; p=0.02) and CON (38.5±0.5°C; p=0.05), while T re in FAN wet (38.2±0.3°C) was lower than FAN dry (p=0.05). End-exercise T re was lower in ICE (38.1±0.3°C) and FAN wet (38.2±0.4°C) than FAN dry (38.9±0.7°C; p<0.04) and CON (38.8±0.5°C; p<0.04).T sk for ICE (35.3±0.8°C) was lower than all conditions, and T sk for FAN wet (36.6±1.1°C) was lower than FAN dry (38.1±1.3°C; p<0.05). TS for ICE and FAN wet were lower than CON and FAN dry (p<0.05). HR was suppressed in ICE and FAN wet relative to CON and FAN dry (p<0.05). WBSR was greater in FAN dry compared to FAN wet (p<0.01) and ICE (p<0.001). Fan use must be used with skin wetting to be effective in hot/dry conditions. This strategy and the currently recommended ICE intervention both reduced T re by ∼0.5-0.6°C and T sk by ∼1.0-1.5°C while mitigating rises in HR and TS. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

A Centennial Episode of Weak East Asian Summer Monsoon in the Midst of the Medieval Warming

NASA Astrophysics Data System (ADS)

Jin, C.; Liu, J.; Wang, B.; Wang, Z.; Yan, M.

2017-12-01

Recent paleo-proxy evidences suggested that the East Asian summer monsoon (EASM) was generally strong (i.e., northern China wet and southern China dry) during the Medieval Warm Period (MWP, 9th to the mid-13th century), however, there was a centennial period (around 11th century) during which the EASM was weak. This study aims to explore the causes of this centennial weak EASM episode and in general, what controls the centennial variability of the EASM in the pre-industrial period of AD 501-1850. With the Community Earth System Model (CESM), a suit of control and forced experiments were conducted for the past 2000 years. The model run with all external forcings simulates a warm period of EA from AD 801-1250 with a generally increased summer mean precipitation over the northern EA; however, during the 11th century (roughly from AD 980 to AD 1100), the EASM is significantly weaker than the other periods during the MWP. We find that on the multi-decadal to centennial time scale, a strong EASM is associated with a La Nina-like Indo-Pacific warming and the opposite is also true. This sea surface temperature (SST) anomaly pattern represents the leading EOF mode of centennial SST variations, and it is primarily forced by the solar radiation and volcanic activity, whereas the land use/land cover and greenhouse gases as well as internal dynamics play a negligible role. During the MWP, the solar forcing plays a dominate role in supporting the SST variation as the volcanic activity is weak. The weakening of the EASM during the AD 980-1100 is attributed to the relatively low solar radiation, which leads to a prevailing El Nino-like Indo-Pacific cooling with strongest cooling occurring in the equatorial western Pacific. The suppressed convection over the equatorial western Pacific directly induces a Philippine Sea anticyclone anomaly, which increases southern China precipitation, meanwhile suppresses Philippine Sea precipitation, exciting a meridional teleconnection that induces anomalous northerly winds and dry conditions over the northern China, weakening the EASM.

Skylight and aerosol in Thailand during the dry winter season.

PubMed

Volz, F; Sheehan, L

1971-02-01

Solar and skylight measurements were made in southern Thailand from late February to early April of 1969. The aerosol optical density (basis 10) was rather large, ranging from 0.07 to 0.28 at lambda0.5 microm and varied with about lambda(-2) in the range 0.5 < lambda < 1.6 microm. The skylight scattering phase function was relatively flat and showed little spectral dependence. The log aerosol size distribution seems close to r(-4). The origin of the turbid low level air from the South China Sea and Philippine Sea poses the question of the nature of the aerosol.

Space Coatings for Industry

NASA Technical Reports Server (NTRS)

1980-01-01

Ball Aerospace developed entirely new space lubrication technologies. A new family of dry lubricants emerged from Apollo, specifically designed for long life in space, together with processes for applying them to spacecraft components in microscopically thin coatings. Lubricants worked successfully on seven Orbiting Solar Observatory flights over the span of a decade and attracted attention to other contractors which became Ball customers. The company has developed several hundred variations of the original OSO technology generally designed to improve the quality and useful life of a wide range of products or improve efficiency of the industrial processes by which such products are manufactured.

The maximal cumulative solar UVB dose allowed to maintain healthy and young skin and prevent premature photoaging.

PubMed

Ichihashi, Masamitsu; Ando, Hideya

2014-10-01

The young facial skin of children with a smooth healthy appearance changes over time to photoaged skin having mottled pigmentation, solar lentigines, wrinkles, dry and rough skin, leathery texture, and benign and malignant tumors after exposure to chronic, repeated solar radiation. The first sign of photoaging in Japanese subjects is usually solar lentigines appearing around 20 years of age on the face. Fine wrinkles can then appear after 30 years of age, and benign skin tumors, seborrhoeic keratoses, can occur after 35 years of age in sun-exposed skin. We theoretically calculated the maximal daily exposure time to solar radiation, which could prevent the development of photoaged skin until 60 and 80 years of age, based on published data of personal solar UVB doses in sun-exposed skin. One MED (minimal erythema dose) was determined to be 20 mJ/cm(2) , and 200 MED was used as the average yearly dose of Japanese children. Further, we hypothesized that the annual dose of Japanese adults is the same as that of the children. The cumulative UVB dose at 20 years of age was thus calculated to be 4000 MED, and 22 MED was used as the maximal daily UVB dose based on data measured in Kobe, located in the central area of Japan. We used the solar UVB dose from 10:00 a.m. to 14:00 p.m. which occupies 60% of the total daily UV dose, to obtain the maximal UVB per hour in a day, and calculated the maximal daily UV exposure time that would delay the onset of solar lentigines until 60 or 80 years of age. The mean daily sun exposure time to maintain healthy skin until 80 years of age in the summer was calculated to be 2.54 min (0.14 MED) for unprotected skin and 127 min with the use of a sunscreen of SPF (sun protection factor) of 50. In this study, we did not evaluate the photoaging effect of UVA radiation, but findings of the adverse effects of UVA radiation on the skin have accumulated in the last decade. Therefore, it will be important to estimate the maximal dose of solar UV radiation to retard the onset of photoaging based on an evaluation of both solar UVB and UVA in the future. Finally, we expect that this study may contribute to keeping Japanese and other types of skin young and healthy by limiting the exposure of the skin to solar radiation outdoors during the day. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Divergent global precipitation changes induced by natural versus anthropogenic forcing.

PubMed

Liu, Jian; Wang, Bin; Cane, Mark A; Yim, So-Young; Lee, June-Yi

2013-01-31

As a result of global warming, precipitation is likely to increase in high latitudes and the tropics and to decrease in already dry subtropical regions. The absolute magnitude and regional details of such changes, however, remain intensely debated. As is well known from El Niño studies, sea-surface-temperature gradients across the tropical Pacific Ocean can strongly influence global rainfall. Palaeoproxy evidence indicates that the difference between the warm west Pacific and the colder east Pacific increased in past periods when the Earth warmed as a result of increased solar radiation. In contrast, in most model projections of future greenhouse warming this gradient weakens. It has not been clear how to reconcile these two findings. Here we show in climate model simulations that the tropical Pacific sea-surface-temperature gradient increases when the warming is due to increased solar radiation and decreases when it is due to increased greenhouse-gas forcing. For the same global surface temperature increase the latter pattern produces less rainfall, notably over tropical land, which explains why in the model the late twentieth century is warmer than in the Medieval Warm Period (around AD 1000-1250) but precipitation is less. This difference is consistent with the global tropospheric energy budget, which requires a balance between the latent heat released in precipitation and radiative cooling. The tropospheric cooling is less for increased greenhouse gases, which add radiative absorbers to the troposphere, than for increased solar heating, which is concentrated at the Earth's surface. Thus warming due to increased greenhouse gases produces a climate signature different from that of warming due to solar radiation changes.

The influence of the push-pull effect and a π-conjugated system in conversion efficiency of bis-chalcone compounds in a dye sensitized solar cell

NASA Astrophysics Data System (ADS)

Teo, Kien Yung; Tiong, Mee Hing; Wee, Hung Yee; Jasin, Nornadia; Liu, Zhi-Qiang; Shiu, Ming Yang; Tang, Jyun Yang; Tsai, Jenn-Kai; Rahamathullah, Rafizah; Khairul, Wan M.; Tay, Meng Guan

2017-09-01

Chalcone and its related compounds are known to be π-conjugated compounds, which can be potentially used in different electronic areas include dye sensitized solar cell (DSSC). A total of six bis-chalcone compounds (1-6) have been synthesized using a Claisen-Schmidt condensation method under basic conditions. The compounds were used as the dye in DSSC to test their solar conversion efficiency. In the process of solar cell fabrication, titanium(II) oxide (TiO2) coated glass was used as the working electrode, whereas the mixture of iodine (I2), lithium iodide (LiI), 4-tertbutylpyridine (4-TBP) and 1,2-dimethyl-3-propylimidazolium (DMPII) in 3-methoxypropionitrile were used as the electrolyte. The DSSC was fabricated by immersing the TiO2 glass into the respective bis-chalcone compound solution and dried into the oven at 45 °C for 120 min. Lastly, the working electrode and counter electrode were sealed using surlyn of 60 μm thickness. The efficiency test was conducted under AM 1.5G illumination with the incident light intensity of 100 mW/cm2. Among the six bis-chalcone derivatives, compound 2, namely 1,4-bis-2-hydroxychalcone, was recorded with the highest efficiency (0.054%) compared to the others (0.022-0.035%). The presence of a π-conjugated system and the push-pull effect in the molecule were found to enhance the conversion efficiency of DSSC. Details of the results are discussed in the present paper.

Relationship between sunlight and the age of onset of bipolar disorder: an international multisite study.

PubMed

Bauer, Michael; Glenn, Tasha; Alda, Martin; Andreassen, Ole A; Angelopoulos, Elias; Ardau, Raffaella; Baethge, Christopher; Bauer, Rita; Bellivier, Frank; Belmaker, Robert H; Berk, Michael; Bjella, Thomas D; Bossini, Letizia; Bersudsky, Yuly; Cheung, Eric Yat Wo; Conell, Jörn; Del Zompo, Maria; Dodd, Seetal; Etain, Bruno; Fagiolini, Andrea; Frye, Mark A; Fountoulakis, Kostas N; Garneau-Fournier, Jade; González-Pinto, Ana; Harima, Hirohiko; Hassel, Stefanie; Henry, Chantal; Iacovides, Apostolos; Isometsä, Erkki T; Kapczinski, Flávio; Kliwicki, Sebastian; König, Barbara; Krogh, Rikke; Kunz, Mauricio; Lafer, Beny; Larsen, Erik R; Lewitzka, Ute; Lopez-Jaramillo, Carlos; MacQueen, Glenda; Manchia, Mirko; Marsh, Wendy; Martinez-Cengotitabengoa, Mónica; Melle, Ingrid; Monteith, Scott; Morken, Gunnar; Munoz, Rodrigo; Nery, Fabiano G; O'Donovan, Claire; Osher, Yamima; Pfennig, Andrea; Quiroz, Danilo; Ramesar, Raj; Rasgon, Natalie; Reif, Andreas; Ritter, Philipp; Rybakowski, Janusz K; Sagduyu, Kemal; Scippa, Ângela M; Severus, Emanuel; Simhandl, Christian; Stein, Dan J; Strejilevich, Sergio; Sulaiman, Ahmad Hatim; Suominen, Kirsi; Tagata, Hiromi; Tatebayashi, Yoshitaka; Torrent, Carla; Vieta, Eduard; Viswanath, Biju; Wanchoo, Mihir J; Zetin, Mark; Whybrow, Peter C

2014-01-01

The onset of bipolar disorder is influenced by the interaction of genetic and environmental factors. We previously found that a large increase in sunlight in springtime was associated with a lower age of onset. This study extends this analysis with more collection sites at diverse locations, and includes family history and polarity of first episode. Data from 4037 patients with bipolar I disorder were collected at 36 collection sites in 23 countries at latitudes spanning 3.2 north (N) to 63.4 N and 38.2 south (S) of the equator. The age of onset of the first episode, onset location, family history of mood disorders, and polarity of first episode were obtained retrospectively, from patient records and/or direct interview. Solar insolation data were obtained for the onset locations. There was a large, significant inverse relationship between maximum monthly increase in solar insolation and age of onset, controlling for the country median age and the birth cohort. The effect was reduced by half if there was no family history. The maximum monthly increase in solar insolation occurred in springtime. The effect was one-third smaller for initial episodes of mania than depression. The largest maximum monthly increase in solar insolation occurred in northern latitudes such as Oslo, Norway, and warm and dry areas such as Los Angeles, California. Recall bias for onset and family history data. A large springtime increase in sunlight may have an important influence on the onset of bipolar disorder, especially in those with a family history of mood disorders. Copyright © 2014 Elsevier B.V. All rights reserved.

Formation of solar system analogues - I. Looking for initial conditions through a population synthesis analysis

NASA Astrophysics Data System (ADS)

Ronco, M. P.; Guilera, O. M.; de Elía, G. C.

2017-11-01

Population synthesis models of planetary systems developed during the last ˜15 yr could reproduce several of the observables of the exoplanet population, and also allowed us to constrain planetary formation models. We present our planet formation model, which calculates the evolution of a planetary system during the gaseous phase. The code incorporates relevant physical phenomena for the formation of a planetary system, like photoevaporation, planet migration, gas accretion, water delivery in embryos and planetesimals, a detailed study of the orbital evolution of the planetesimal population, and the treatment of the fusion between embryos, considering their atmospheres. The main goal of this work, unlike other works of planetary population synthesis, is to find suitable scenarios and physical parameters of the disc to form Solar system analogues. We are specially interested in the final planet distributions, and in the final surface density, eccentricity and inclination profiles for the planetesimal population. These final distributions will be used as initial conditions for N-body simulations to study the post-oligarchic formation in a second work. We then consider different formation scenarios, with different planetesimal sizes and different type I migration rates. We find that Solar system analogues are favoured in massive discs, with low type I migration rates, and small planetesimal sizes. Besides, those rocky planets within their habitables zones are dry when discs dissipate. At last, the final configurations of Solar system analogues include information about the mass and semimajor axis of the planets, water contents, and the properties of the planetesimal remnants.

On the Path to SunShot: Advancing Concentrating Solar Power Technology Performance and Dispatchability.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mehos, Mark; Turchi, Craig; Jorgensen, Jennie

2016-03-01

Since the SunShot Vision Study (DOE 2012) was published, global deployment of concentrating solar power (CSP) has increased threefold to nearly 4,500 MW, with a similar threefold increase in operational capacity to 1,650 MW within the United States. Growth in U.S. CSP capacity has primarily been driven by policy support at the state and federal levels. State-driven renewable portfolio standards (RPSs), combined with a 30% federal investment tax credit (ITC) and federal loan guarantees, provided the opportunity for CSP developers to kick-start construction of CSP plants throughout the Southwest. Figure ES-1 demonstrates that deployment and private- and public-sector research andmore » development have led to dramatic cost reductions that have placed CSP well on the path to reaching the U.S. Department of Energy’s SunShot Initiative goal of 6 cents/kWh by 2020. In comparing the estimated capital costs from the SunShot Vision Study and the current analysis, we find that parabolic trough solar-field costs have fallen more rapidly than predicted, although the drop in solar-field costs was offset by the additional costs of moving from a wet-cooled power block in 2010 to a more expensive dry-cooled power block in 2015. The predicted 2015 decline in tower costs was in line with expectations, primarily driven by reduced heliostat costs. Figure ES-1 shows the reduction in levelized cost of electricity (LCOE) for both parabolic trough and tower systems, in addition to the projected 2020 SunShot target.« less

Biomass production and nutrient removal potential of water hyacinth cultured in sewage effluent

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reddy, K.R.; Hueston, F.M.; McKim, T.

1985-05-01

Growth and nutrient uptake of water hyacinth (Eichhornia crassipes (Mart) Solms) cultured in sewage effluent were measured over a period of 1 year in a prototype wastewater treatment system which has been in operation at Walt Disney World near Orlando, Florida. Annual productivity of water hyacinth cultured in primary sewage effluent (Channel II) was found to be in the range of 5 to 27 g dry wt m/sup -2/ day/sup -1/ (23.6 dry tons acre/sup -1/ yr/sup -1/). Average growth rate during the months of May through October 1982 for hyacinth cultured in Channel II (primary sewage effluent) and Channelmore » I (treated primary sewage effluent leaving Channel II) was about 16 g dry wt m/sup -2/ day/sup -1/ (27 dry tons acre/sup -1/ yr/sup -1/), compared to the growth rate of 13 g dry wt m/sup -2/ day/sup -1/ (22 dry tons acre/sup -1/ yr/sup -1/) for hyacinths cultured in secondary sewage effluent. Plants cultured in secondary sewage effluent generally had longer roots than the plants cultured in primary sewage effluent. A significant relationship was observed between the growth rate of hyacinth and the solar radiation. Nitrogen and P concentration of the plant tissue were higher in the hyacinths cultured during winter months compared to the plants grown in summer months. Average N and P concentration of the plants cultured in primary sewage effluent were found to be 3.7 percent N and 0.94 percent P, respectively, while the plants cultured in secondary sewage effluent had a total N and P content of 2.8 percent N and 0.79 percent P. Nutrient ratios of the major plant nutrients were found to be approximately the same as the nutrient ratios in the sewage effluent. Annual N and P uptake rates of hyacinth cultured in sewage effluent were found to be in the range of 1176 to 1193 kg N ha/sup -1/ yr/sup -1/ and 321 to 387 kg P ha/sup -1/ yr/sup -1/, respectively.« less

3D Orbit Visualization for Earth-Observing Missions

NASA Technical Reports Server (NTRS)

Jacob, Joseph C.; Plesea, Lucian; Chafin, Brian G.; Weiss, Barry H.

2011-01-01

This software visualizes orbit paths for the Orbiting Carbon Observatory (OCO), but was designed to be general and applicable to any Earth-observing mission. The software uses the Google Earth user interface to provide a visual mechanism to explore spacecraft orbit paths, ground footprint locations, and local cloud cover conditions. In addition, a drill-down capability allows for users to point and click on a particular observation frame to pop up ancillary information such as data product filenames and directory paths, latitude, longitude, time stamp, column-average dry air mole fraction of carbon dioxide, and solar zenith angle. This software can be integrated with the ground data system for any Earth-observing mission to automatically generate daily orbit path data products in Google Earth KML format. These KML data products can be directly loaded into the Google Earth application for interactive 3D visualization of the orbit paths for each mission day. Each time the application runs, the daily orbit paths are encapsulated in a KML file for each mission day since the last time the application ran. Alternatively, the daily KML for a specified mission day may be generated. The application automatically extracts the spacecraft position and ground footprint geometry as a function of time from a daily Level 1B data product created and archived by the mission s ground data system software. In addition, ancillary data, such as the column-averaged dry air mole fraction of carbon dioxide and solar zenith angle, are automatically extracted from a Level 2 mission data product. Zoom, pan, and rotate capability are provided through the standard Google Earth interface. Cloud cover is indicated with an image layer from the MODIS (Moderate Resolution Imaging Spectroradiometer) aboard the Aqua satellite, which is automatically retrieved from JPL s OnEarth Web service.

Chemical composition of solar dried blood and the ruminal content and its effect on performance of Japanese quails.

PubMed

Mishra, Jyotiprabha; Abraham, Robinson J J; Rao, V Appa; Rajini, R Asha; Mishra, B P; Sarangi, N R

2015-01-01

The aim was to determine the chemical composition of solar dried blood and rumen content (DBRC) and further ascertain the concentration at which DBRC could be included in Japanese quail diets without any adverse effect on its performance. Feeding trial on the effect of DBRC on performance of Japanese quails was studied up to 5 weeks. 252 numbers of day old (Nandanam Type III breed) Japanese quails were purchased from Poultry Research Station, Madhavaram and divided into 7 batches (control+ six treatments) each consisting of 36 birds. The DBRC was included at 0%, 5%, 10%, 15%, 20%, 25% and 30% in diets as control, treatment-1 (T1), treatment-2 (T2), treatment-3 (T3), treatment-4 (T4), treatment-5 (T5) and treatment-6 (T6) respectively in a completely randomized design to replace soybean meal in Japanese quail feed. The birds were provided with ad-labidum feed and drinking water ad-libitum during the entire experimental period. The crude protein (CP), crude fiber (CF), ether extract (EE) and ash contents of DBRC were 35.87%, 17.40%, 3.6% and 12.6%, respectively. The amount of essential amino acids and non-essential amino acid content were found to be 12.98 and 4.87 (g/100 g of feed) respectively in DBRC feed. Result showed that all birds fed DBRC diets performed better than the control group. Mortality was unaffected by dietary treatments. There was a significant difference (p<0.01) observed in weight gain in treatment groups compared to the control. Up to 30% DBRC could be incorporated in the diets of Japanese quails without any adverse effects on its performance.

Stomatal Conductance, Plant Hydraulics, and Multilayer Canopies: A New Paradigm for Earth System Models or Unnecessary Uncertainty

NASA Astrophysics Data System (ADS)

Bonan, G. B.

2016-12-01

Soil moisture stress is a key regulator of canopy transpiration, the surface energy budget, and land-atmosphere coupling. Many land surface models used in Earth system models have an ad-hoc parameterization of soil moisture stress that decreases stomatal conductance with soil drying. Parameterization of soil moisture stress from more fundamental principles of plant hydrodynamics is a key research frontier for land surface models. While the biophysical and physiological foundations of such parameterizations are well-known, their best implementation in land surface models is less clear. Land surface models utilize a big-leaf canopy parameterization (or two big-leaves to represent the sunlit and shaded canopy) without vertical gradients in the canopy. However, there are strong biometeorological and physiological gradients in plant canopies. Are these gradients necessary to resolve? Here, I describe a vertically-resolved, multilayer canopy model that calculates leaf temperature and energy fluxes, photosynthesis, stomatal conductance, and leaf water potential at each level in the canopy. In this model, midday leaf water stress manifests in the upper canopy layers, which receive high amounts of solar radiation, have high leaf nitrogen and photosynthetic capacity, and have high stomatal conductance and transpiration rates (in the absence of leaf water stress). Lower levels in the canopy become water stressed in response to longer-term soil moisture drying. I examine the role of vertical gradients in the canopy microclimate (solar radiation, air temperature, vapor pressure, wind speed), structure (leaf area density), and physiology (leaf nitrogen, photosynthetic capacity, stomatal conductance) in determining above canopy fluxes and gradients of transpiration and leaf water potential within the canopy.

The impacts of the dust radiative effect on vegetation growth in the Sahel

NASA Astrophysics Data System (ADS)

Evans, S. M.; Shevliakova, E.; Malyshev, S.; Ginoux, P. A.

2017-12-01

Many studies have been conducted on the effects of dust on rainfall in the Sahel, and generally show that African dust weakens the West African Monsoon, drying the region. This drying is often assumed to reduce vegetation cover for the region, providing a positive feedback with dust emission. There are, however, other competing effects of dust that are also important to plant growth, including a reduction in surface temperature, a reduction in downwelling solar radiation, and an increase in the diffuse fraction of that solar radiation. Using the NOAA/GFDL CM3 model coupled to the dynamic vegetation model LM3, we demonstrate that the combined effect of all these processes is to decrease the vegetation coverage and productivity of the Sahel and West Africa. We accomplish this by comparing experiments with radiatively active dust to experiments with radiatively invisible dust. We find that in modern conditions, the dust radiative effect reduces the net primary productivity of West Africa and the Sahel by up to 30% locally, and when summed over the region accounts for a difference of approximately 0.4 GtC per year. Experiments where the vegetation experiences preindustrial rather than modern CO2 levels show that without carbon fertilization, this loss of productivity would be approximately 10% stronger. In contrast, during preindustrial conditions the vegetation response is less than half as strong, despite the dust induced rainfall and temperature anomalies being similar. We interpret this as the vegetation being less susceptible to drought in a less evaporative climate. These changes in vegetation create the possibility of a dust-vegetation feedback loop whose strength varies with the mean state of the climate, and which may grow stronger in the future.

Modeling and improving Ethiopian pasture systems

NASA Astrophysics Data System (ADS)

Parisi, S. G.; Cola, G.; Gilioli, G.; Mariani, L.

2018-01-01

The production of pasture in Ethiopia was simulated by means of a dynamic model. Most of the country is characterized by a tropical monsoon climate with mild temperatures and precipitation mainly concentrated in the June-September period (main rainy season). The production model is driven by solar radiation and takes into account limitations due to relocation, maintenance respiration, conversion to final dry matter, temperature, water stress, and nutrients availability. The model also considers the senescence of grassland which strongly limits the nutritional value of grasses for livestock. The simulation for the 1982-2009 period, performed on gridded daily time series of rainfall and maximum and minimum temperature with a resolution of 0.5°, provided results comparable with values reported in literature. Yearly mean yield in Ethiopia ranged between 1.8 metric ton per hectare (t ha-1) (2002) and 2.6 t ha-1 (1989) of dry matter with values above 2.5 t ha-1 attained in 1983, 1985, 1989, and 2008. The Ethiopian territory has been subdivided in 1494 cells and a frequency distribution of the per-cell yearly mean pasture production has been obtained. This distribution ranges from 0 to 7 t ha-1 and it shows a right skewed distribution and a modal class between 1.5-2 t ha-1. Simulation carried out on long time series for this peculiar tropical environment give rise to as lot of results relevant by the agroecological point of view on space variability of pasture production, main limiting factors (solar radiation, precipitation, temperature), and relevant meteo-climatic cycles affecting pasture production (seasonal and inter yearly variability, ENSO). These results are useful to establish an agro-ecological zoning of the Ethiopian territory.

Cryoseism Vibrational Movement and Sorting of Detritus of Mars' Regolith Bedforms (E.G., ~ Streaks, Gullies): a New, Dry, Midsummer Antarctic Analogue Mechanism

NASA Astrophysics Data System (ADS)

Ford, A. B.

2015-12-01

"SNAP!, CRACK!, POP!" The sounds reverberated across newly shaded permafrost of unusual talus aprons (Ford & Andersen, 1967; J. Geol., 75, 722-732) of interior Antarctica (lats. >84°S; Thiel, Pensacola mtns.), coming from ice cracking under tensile failure (cryoseisms). Apron regoliths show conspicuously reversed downslope particle-size sorting and downslope-oriented lineations (debris-cleared tracts; stone stripes) formed by vibrational movement of detritus by midsummer, diurnal cracking of ice. Moving laterally by vibrations away from cracks, with downslope component by gravity, finer detritus becomes concentrated downslope from coarser debris of initial cliff fall — winnowed, as if on a gigantic vibrating shaking table. Slopes outside shade zones remain free of cracking. Diurnal midday shading of solar-warmed, debris-mantled permafrost- and glacier-surface ice at low ambient midsummer temperatures produces high strain-loading rates that exceed tensile toughness of inhomogeneous, polycrystalline ice containing zones of older but sealed cracks. This dry, mechanical, cryoseism mechanism is here proposed also for now waterless Mars and other icy Solar System bodies. Regolith features of Mars' cryosphere may appear different from anrarctic analogues owing to likely operation over tens if not hundreds of millions of years longer than on Earth. The strain distributions in tensile failure of ice better explain a common spacing uniformity of many martian linear features than others' proposed origins, and for some "active" streaks and gully channels, TARS, RSL and dune-slipface channels, as well as for dune orthogonality, diurnal moonquakes and asteroid-regolith detrital sorting (e.g., "rubble-pile" 25143-Itokawa). Because periodic shade from topography (canyons, craters, etc.) is needed, the mechanism is not expected on flattish terrains where more normal annual cooling rates produce the common polygonal tensile fracturing of ice

Modeling and improving Ethiopian pasture systems

NASA Astrophysics Data System (ADS)

Parisi, S. G.; Cola, G.; Gilioli, G.; Mariani, L.

2018-05-01

The production of pasture in Ethiopia was simulated by means of a dynamic model. Most of the country is characterized by a tropical monsoon climate with mild temperatures and precipitation mainly concentrated in the June-September period (main rainy season). The production model is driven by solar radiation and takes into account limitations due to relocation, maintenance respiration, conversion to final dry matter, temperature, water stress, and nutrients availability. The model also considers the senescence of grassland which strongly limits the nutritional value of grasses for livestock. The simulation for the 1982-2009 period, performed on gridded daily time series of rainfall and maximum and minimum temperature with a resolution of 0.5°, provided results comparable with values reported in literature. Yearly mean yield in Ethiopia ranged between 1.8 metric ton per hectare (t ha-1) (2002) and 2.6 t ha-1 (1989) of dry matter with values above 2.5 t ha-1 attained in 1983, 1985, 1989, and 2008. The Ethiopian territory has been subdivided in 1494 cells and a frequency distribution of the per-cell yearly mean pasture production has been obtained. This distribution ranges from 0 to 7 t ha-1 and it shows a right skewed distribution and a modal class between 1.5-2 t ha-1. Simulation carried out on long time series for this peculiar tropical environment give rise to as lot of results relevant by the agroecological point of view on space variability of pasture production, main limiting factors (solar radiation, precipitation, temperature), and relevant meteo-climatic cycles affecting pasture production (seasonal and inter yearly variability, ENSO). These results are useful to establish an agro-ecological zoning of the Ethiopian territory.

Chemical composition of solar dried blood and the ruminal content and its effect on performance of Japanese quails

PubMed Central

Mishra, Jyotiprabha; Abraham, Robinson J. J; Rao, V. Appa; Rajini, R. Asha; Mishra, B. P.; Sarangi, N. R.

2015-01-01

Aim: The aim was to determine the chemical composition of solar dried blood and rumen content (DBRC) and further ascertain the concentration at which DBRC could be included in Japanese quail diets without any adverse effect on its performance. Materials and Methods: Feeding trial on the effect of DBRC on performance of Japanese quails was studied up to 5 weeks. 252 numbers of day old (Nandanam Type III breed) Japanese quails were purchased from Poultry Research Station, Madhavaram and divided into 7 batches (control+ six treatments) each consisting of 36 birds. The DBRC was included at 0%, 5%, 10%, 15%, 20%, 25% and 30% in diets as control, treatment-1 (T1), treatment-2 (T2), treatment-3 (T3), treatment-4 (T4), treatment-5 (T5) and treatment-6 (T6) respectively in a completely randomized design to replace soybean meal in Japanese quail feed. The birds were provided with ad-labidum feed and drinking water ad-libitum during the entire experimental period. Results: The crude protein (CP), crude fiber (CF), ether extract (EE) and ash contents of DBRC were 35.87%, 17.40%, 3.6% and 12.6%, respectively. The amount of essential amino acids and non-essential amino acid content were found to be 12.98 and 4.87 (g/100 g of feed) respectively in DBRC feed. Result showed that all birds fed DBRC diets performed better than the control group. Mortality was unaffected by dietary treatments. There was a significant difference (p<0.01) observed in weight gain in treatment groups compared to the control. Conclusion: Up to 30% DBRC could be incorporated in the diets of Japanese quails without any adverse effects on its performance. PMID:27047002

Atmospheric circulations of terrestrial planets orbiting low-mass stars

NASA Astrophysics Data System (ADS)

Edson, Adam; Lee, Sukyoung; Bannon, Peter; Kasting, James F.; Pollard, David

2011-03-01

Circulations and habitable zones of planets orbiting low-mass stars are investigated. Many of these planets are expected to rotate synchronously relative to their parent stars, thereby raising questions about their surface temperature distributions and habitability. We use a global circulation model to study idealized, synchronously rotating (tidally locked) planets of various rotation periods, with surfaces of all land or all water, but with an Earth-like atmosphere and solar insolation. The dry planets exhibit wide variations in surface temperature: >80 °C on the dayside to <-110 °C on the nightside for the 240-h rotator, for example. The water-covered aquaplanets are warmer and exhibit narrower ranges of surface temperatures, e.g., ∼40 °C to >-60 °C for the 240-h orbiter. They also have a larger habitable area, defined here as the region where average surface temperatures are between 0 °C and 50 °C. This concept has little relevance for either dry or aquaplanets, but might become relevant on a planet with both land area and oceans. The circulations on these tidally locked planets exhibit systematic changes as the rotation period is varied. However, they also reveal abrupt transitions between two different circulation regimes and multiple equilibria. For the dry planet, the transition occurs between a 4-day and a 5-day period, while for the aquaplanet, it occurs between a 3-day and a 4-day period. For both dry and aqua planets, this transition occurs when the Rossby deformation radius exceeds half the planetary radius. Further investigation on the dry planet reveals that multiple equilibria exist between 100- and 221-h periods. These multiple equilibria may be relevant for real planets within the habitable zones of late K and M stars, because these planets are expected to have rotation periods between 8 and 100 Earth days.

Tuber yield and quality characteristics of potatoes for off-season crops in a Mediterranean environment.

PubMed

Ierna, Anita

2010-01-15

There is little research on evaluating the compatibility of potatoes for double cropping in southern Italy. The aim of this investigation was to assess tuber yield and some qualitative traits of tubers such as skin colour, tuber dry matter content and tuber nitrate content, both in winter-spring and in summer-autumn crops, as influenced by genotype and harvest time. Yield, skin colour and dry matter content of tubers were higher in the winter-spring crop than in the summer-autumn crop, attributable to the advantageous lag time in spring between solar radiation and temperatures and the disadvantageous lag in autumn. Spunta and Arinda performed well within each crop season, whereas Ninfa showed an important yield loss in autumn. In both off-season crops, delaying tuber harvest until leaf senescence increased yield and improved quality attributes such as tuber dry matter content and skin colour, whereas nitrate contents significantly decreased in the winter-spring crop and increased in the summer-autumn crop. Ninfa showed less tendency than Arinda and Spunta to accumulate nitrate in tubers in both off-season crops. It might be advantageous to examine in further research which mechanisms sustain compatibility to the autumn and assess other quality characteristics for the fresh market in the contrasting climatic conditions of the two off-season crops. Copyright (c) 2009 Society of Chemical Industry.

The McMurdo Dry Valleys: A landscape on the threshold of change

NASA Astrophysics Data System (ADS)

Fountain, Andrew G.; Levy, Joseph S.; Gooseff, Michael N.; Van Horn, David

2014-11-01

Field observations of coastal and lowland regions in the McMurdo Dry Valleys suggest they are on the threshold of rapid topographic change, in contrast to the high elevation upland landscape that represents some of the lowest rates of surface change on Earth. A number of landscapes have undergone dramatic and unprecedented landscape changes over the past decade including, the Wright Lower Glacier (Wright Valley) - ablated several tens of meters, the Garwood River (Garwood Valley) has incised > 3 m into massive ice permafrost, smaller streams in Taylor Valley (Crescent, Lawson, and Lost Seal Streams) have experienced extensive down-cutting and/or bank undercutting, and Canada Glacier (Taylor Valley) has formed sheer, > 4 meter deep canyons. The commonality between all these landscape changes appears to be sediment on ice acting as a catalyst for melting, including ice-cement permafrost thaw. We attribute these changes to increasing solar radiation over the past decade despite no significant trend in summer air temperature. To infer possible future landscape changes in the McMurdo Dry Valleys, due to anticipated climate warming, we map ‘at risk’ landscapes defined as those with buried massive ice in relative warm regions of the valleys. Results show that large regions of the valley bottoms are ‘at risk’. Changes in surface topography will trigger important responses in hydrology, geochemistry, and biological community structure and function.

Adaptations of the reed frog Hyperolius viridiflavus (Amphibia, Anura, Hyperoliidae) to its arid environment : I. The skin of Hyperolius viridiflavus nitidulus in wet and dry season conditions.

PubMed

Kobelt, Frank; Linsenmair, K E

1986-03-01

Hyperolius viridiflavus nitidulus inhabits parts of the seasonally very hot and dry West African savanna. During the long lasting dry season, the small frog is sitting unhidden on mostly dry plants and has to deal with high solar radiation load (SRL), evaporative water loss (EWL) and small energy reserves. It seems to be very badly equipped to survive such harsh climatic conditions (unfavorable surface to volume ratio, very limited capacity to store energy and water). Therefore, it must have developed extraordinary efficient mechanisms to solve the mentioned problems. Some of these mechanisms are to be looked for within the skin of the animal (e.g. protection against fast desiccation, deleterious effects of UV radiation and overheating). The morphology of the wet season skin is, in most aspects, that of a "normal" anuran skin. It differs in the organization of the processes of the melanophores and in the arrangement of the chromatophores in the stratum spongiosum, forming no "Dermal Chromatophore Unit". During the adaptation to dry season conditions the number of iridophores in dorsal and ventral skin is increased 4-6 times compared to wet season skin. This increase is accompanied by a very conspicuous change of the wet season color pattern. Now, at air temperatures below 35° C the color becomes brownish white or grey and changes to a brilliant white at air temperatures near and over 40° C. Thus, in dry season state the frog retains its ability for rapid color change. In wet season state the platelets of the iridophores are irregularly distributed. In dry season state many platelets become arranged almost parallel to the surface. These purine crystals probably act as quarter-wave-length interference reflectors, reducing SRL by reflecting a considerable amount of the radiated energy input.EWL is as low as that of much larger xeric reptilians. The impermeability of the skin seems to be the result of several mechanisms (ground substance, iridophores, lipids, mucus) supplementing each other.The light red skin at the pelvic region and inner sides of the limbs is specialized for rapid uptake of water allowing the frog to replenish the unavoidable EWL by using single drops of dew or rain, available for only very short periods.

The use of oxygen isotopes of diatom silica in a decadal to centennial palaeonvironmental reconstruction

NASA Astrophysics Data System (ADS)

Hernández, A.; Giralt, S.; Bao, R.; Sáez, A.; Leng, M. J.; Barker, P. A.

2009-04-01

The Lateglacial-early Holocene transition from the Lago Chungará record (northern Chilean Altiplano) is made up of laminated sediments composed by light and dark pluriannual couplets of diatomaceous ooze. Light sediment laminae accumulated during short-term diatom blooms whereas dark sediment laminae represent the baseline limnological conditions during several years of deposition. Diatom oxygen isotope data (_18Odiatom) of dark diatom laminae from Lago Chungará show evidence that the Lateglacial-early Holocene transition (11,990-11,475 cal years BP) occurred in a series of decadal-to-centennial wet-dry oscillations. Dry periods are marked by relatively high isotope values whereas wet episodes are indicated by lower isotope values. This fact is supported by data on allochtonous inputs and water availability curves from Lago Chungará previously published (Giralt et al. 2008). They highlight the sedimentological and environmental processes that occurred during these wet and dry episodes. The delta_18Odiatom record documents at least two episodes of increased effective moisture at a centennial-scale (ca.11,800 and 11,550 cal years BP) and only one important period of increasing aridity (between ca. 11,990 and 11,800 cal years BP). However, up to seven wet episodes and at least six dry events at a decadal scale are superimposed to the normal conditions. The spectral analyses of the delta_18Odiatom values suggest that these changes could be triggered by both El Niño-Southern Oscillation (ENSO) and solar activity. Time-frequency analysis shows that the activity of these two forcings was more intense during Lateglacial than during the onset of the Holocene. This last period could be governed by La Niña-like conditions that correspond to wet conditions over the Andean Altiplano.

Seasonal soil moisture and drought occurrence in Europe in CMIP5 projections for the 21st century

NASA Astrophysics Data System (ADS)

Ruosteenoja, Kimmo; Markkanen, Tiina; Venäläinen, Ari; Räisänen, Petri; Peltola, Heli

2018-02-01

Projections for near-surface soil moisture content in Europe for the 21st century were derived from simulations performed with 26 CMIP5 global climate models (GCMs). Two Representative Concentration Pathways, RCP4.5 and RCP8.5, were considered. Unlike in previous research in general, projections were calculated separately for all four calendar seasons. To make the moisture contents simulated by the various GCMs commensurate, the moisture data were normalized by the corresponding local maxima found in the output of each individual GCM. A majority of the GCMs proved to perform satisfactorily in simulating the geographical distribution of recent soil moisture in the warm season, the spatial correlation with an satellite-derived estimate varying between 0.4 and 0.8. In southern Europe, long-term mean soil moisture is projected to decline substantially in all seasons. In summer and autumn, pronounced soil drying also afflicts western and central Europe. In northern Europe, drying mainly occurs in spring, in correspondence with an earlier melt of snow and soil frost. The spatial pattern of drying is qualitatively similar for both RCP scenarios, but weaker in magnitude under RCP4.5. In general, those GCMs that simulate the largest decreases in precipitation and increases in temperature and solar radiation tend to produce the most severe soil drying. Concurrently with the reduction of time-mean soil moisture, episodes with an anomalously low soil moisture, occurring once in 10 years in the recent past simulations, become far more common. In southern Europe by the late 21st century under RCP8.5, such events would be experienced about every second year.

The universe: a cryogenic habitat for microbial life.

PubMed

Wickramasinghe, Chandra

2004-04-01

Panspermia, an ancient idea, posits that microbial life is ubiquitous in the Universe. After several decades of almost irrational rejection, panspermia is at last coming to be regarded as a serious contender for the beginnings of life on our planet. Astronomical data is shown to be consistent with the widespread distribution of complex organic molecules and dust particles that may have a biological provenance. A minuscule (10(-21)) survival rate of freeze-dried bacteria in space is all that is needed to ensure the continual re-cycling of cosmic microbial life in the galaxy. Evidence that terrestrial life may have come from elsewhere in the solar system has accumulated over the past decade. Mars is seen by some as a possible source of terrestrial life, but some hundreds of billions of comets that enveloped the entire solar system, are a far more likely primordial reservoir of life. Comets would then have seeded Earth, Mars, and indeed all other habitable planetary bodies in the inner regions of the solar system. The implications of this point of view, which was developed in conjunction with the late Sir Fred Hoyle since the 1970s, are now becoming amenable to direct empirical test by studies of pristine organic material in the stratosphere. The ancient theory of panspermia may be on the verge of vindication, in which case the entire universe would be a grand crucible of cryomicrobiology.

The Universe: a Cryogenic Habitat for Microbial Life

NASA Astrophysics Data System (ADS)

Wickramasinghe, Chandra

Panspermia, an ancient idea, posits that microbial life is ubiquitous in the Universe. After several decades of almost irrational rejection, panspermia is at last coming to be regarded as a serious contender for the beginnings of life on our planet. Astronomical data is shown to be consistent with the widespread distribution of complex organic molecules and dust particles that may have a biological provenance. A minuscule (10-21) survival rate of freeze-dried bacteria in space is all that is needed to ensure the continual recycling of cosmic microbial life in the galaxy. Evidence that terrestrial life may have come from elsewhere in the solar system has accumulated over the past decade. Mars is seen by some as a possible source of terrestrial life, but some hundreds of billions of comets that enveloped the entire solar system, are a far more likely primordial reservoir of life. Comets would then have seeded Earth, Mars, and indeed all other habitable planetary bodies in the inner regions of the solar system. The implications of this point of view, which was developed in conjunction with the late Sir Fred Hoyle since the 1970's, are now becoming amenable to direct empirical test by studies of pristine organic material in the stratosphere. The ancient theory of panspermia may be on the verge of vindication, in which case the entire universe would be a grand crucible of cryomicrobiology.

Spacecraft Mission Design for the Mitigation of the 2017 PDC Hypothetical Asteroid Threat

NASA Technical Reports Server (NTRS)

Barbee, Brent W.; Sarli, Bruno V.; Lyzhoft, Joshua; Chodas, Paul W.; Englander, Jacob A.

2017-01-01

This paper presents a detailed mission design analysis results for the 2017 Planetary Defense Conference (PDC) Hypothetical Asteroid Impact Scenario, documented at https://cneos.jpl.nasa.gov/ pd/cs/pdc17/. The mission design includes campaigns for both reconnaissance (flyby or rendezvous) of the asteroid (to characterize it and the nature of the threat it poses to Earth) and mitigation of the asteroid, via kinetic impactor deflection, nuclear explosive device (NED) deflection, or NED disruption. Relevant scenario parameters are varied to assess the sensitivity of the design outcome, such as asteroid bulk density, asteroid diameter, momentum enhancement factor, spacecraft launch vehicle, and mitigation system type. Different trajectory types are evaluated in the mission design process from purely ballistic to those involving optimal midcourse maneuvers, planetary gravity assists, and/or lowthrust solar electric propulsion. The trajectory optimization is targeted around peak deflection points that were found through a novel linear numerical technique method. The optimization process includes constrain parameters, such as Earth departure date, launch declination, spacecraft/asteroid relative velocity and solar phase angle, spacecraft dry mass, minimum/maximum spacecraft distances from Sun and Earth, and Earth/spacecraft communications line of sight. Results show that one of the best options for the 2017 PDC deflection is solar electric propelled rendezvous mission with a single spacecraft using NED for the deflection

High-Efficiency Polycrystalline CdS/CdTe Solar Cells on Buffered Commercial TCO-Coated Glass

NASA Astrophysics Data System (ADS)

Colegrove, E.; Banai, R.; Blissett, C.; Buurma, C.; Ellsworth, J.; Morley, M.; Barnes, S.; Gilmore, C.; Bergeson, J. D.; Dhere, R.; Scott, M.; Gessert, T.; Sivananthan, Siva

2012-10-01

Multiple polycrystalline CdS/CdTe solar cells with efficiencies greater than 15% were produced on buffered, commercially available Pilkington TEC Glass at EPIR Technologies, Inc. (EPIR, Bolingbrook, IL) and verified by the National Renewable Energy Laboratory (NREL). n-CdS and p-CdTe were grown by chemical bath deposition (CBD) and close space sublimation, respectively. Samples with sputter-deposited CdS were also investigated. Initial results indicate that this is a viable dry-process alternative to CBD for production-scale processing. Published results for polycrystalline CdS/CdTe solar cells with high efficiencies are typically based on cells using research-grade transparent conducting oxides (TCOs) requiring high-temperature processing inconducive to low-cost manufacturing. EPIR's results for cells on commercial glass were obtained by implementing a high-resistivity SnO2 buffer layer and by optimizing the CdS window layer thickness. The high-resistivity buffer layer prevents the formation of CdTe-TCO junctions, thereby maintaining a high open-circuit voltage and fill factor, whereas using a thin CdS layer reduces absorption losses and improves the short-circuit current density. EPIR's best device demonstrated an NREL-verified efficiency of 15.3%. The mean efficiency of hundreds of cells produced with a buffer layer between December 2010 and June 2011 is 14.4%. Quantum efficiency results are presented to demonstrate EPIR's progress toward NREL's best-published results.

Full coverage of perovskite layer onto ZnO nanorods via a modified sequential two-step deposition method for efficiency enhancement in perovskite solar cells

NASA Astrophysics Data System (ADS)

Ruankham, Pipat; Wongratanaphisan, Duangmanee; Gardchareon, Atcharawon; Phadungdhitidhada, Surachet; Choopun, Supab; Sagawa, Takashi

2017-07-01

Full coverage of perovskite layer onto ZnO nanorod substrates with less pinholes is crucial for achieving high-efficiency perovskite solar cells. In this work, a two-step sequential deposition method is modified to achieve an appropriate property of perovskite (MAPbI3) film. Surface treatment of perovskite layer and its precursor have been systematically performed and their morphologies have been investigated. By pre-wetting of lead iodide (PbI2) and letting it dry before reacting with methylammonium iodide (MAI) provide better coverage of perovskite film onto ZnO nanorod substrate than one without any treatment. An additional MAI deposition followed with toluene drop-casting technique on the perovskite film is also found to increase the coverage and enhance the transformation of PbI2 to MAPbI3. These lead to longer charge carrier lifetime, resulting in an enhanced power conversion efficiency (PCE) from 1.21% to 3.05%. The modified method could been applied to a complex ZnO nanorods/TiO2 nanoparticles substrate. The enhancement in PCE to 3.41% is observed. These imply that our introduced method provides a simple way to obtain the full coverage and better transformation to MAPbI3 phase for enhancement in performances of perovskite solar cells.

Educational, scientific, tourist and outreach potential of the September 1, 2016 Annular Solar Eclipse in Tanzania

NASA Astrophysics Data System (ADS)

Tayabali Jiwaji, Noorali

2015-08-01

Tanzania will witness a major astronomical spectacle of an annular eclipse on September 1, 2016. The central part of the eclipse will pass through southern Tanzania, crossing national parks and game reserves such as Katavi and the world famous Selous. For the rest of Tanzania and neighbouring countries it will be a memorable event with large of the proportion of the Sun being covered up. The climate in Tanzania during September is cool and dry which will provide ideal viewing conditions. Solar eclipse events attract "eclipse chasers" from around the globe.Scientific interest in measuring the properties of the Sun and the effects of the eclipse on the atmosphere will allow local scientists to partner with leading scientists to gain valuable experience and knowledge.Local population's wonder and interest in eclipses can be exploited through public-private partnerships by encouraging students and local people to travel to the central path or to observe from their backyards. Large number of eclipse glasses can be manufactured cheaply using safe solar filters for supplying to students and general population in Tanzania and neigbouring countries. This will raise science awareness about the wonders of our Universe.When combined with the attraction of Tanzania's treasures in the north and the 16 tonne Mbozi meteorite in southern Tanzania, the touristic potential of this event can be exploited through tour packages and worldwide advertisements during the coming year.

Genotoxic action of sunlight upon Bacillus subtilis spores: monitoring studies at Tokyo, Japan.

PubMed

Munakata, N

1989-12-01

Samples of Bacillus subtilis spores dried on membrane filter were exposed to natural sunlight from solar-noon time at Tokyo. The survival and mutation induction of wild-type (UVR) and repair-deficient (UVS) spores were determined on 66 occasions since 1979. Two of the values were considered to be useful in monitoring solar UV intensity; the inverse of the time (in minutes) of exposure to kill 63% of the UVS spores ("sporocidal index") and the induced mutation frequency at 60 minutes of exposure of the UVR spores ("mutagenic index"). Both values were varied greatly due to time of a year, weather and other conditions. Estimates of year-round changes under clear skies were obtained by connecting the maximum values attained in these years. In these curves, there are more than 7-fold differences in the genotoxicity between winter and summer months, with major increases observed in early spring and decreases through autumn. Using a series of UV cut-off filters, the wavelengths most effective for the sporocidal actions were estimated to be in the range of 308-325 nm, shorter wavelengths being effective when the genotoxicity was higher. Sunburn meter of Robertson-Berger type seems to respond to slightly longer wavelength components of the solar spectrum. However, a reasonable correlation was obtained between the reading of the meter and the sporocidal index.

Biological Sensors for Solar Ultraviolet Radiation

PubMed Central

Yagura, Teiti; Makita, Kazuo; Yamamoto, Hiromasa; Menck, Carlos F.M.; Schuch, André P.

2011-01-01

Solar ultraviolet (UV) radiation is widely known as a genotoxic environmental agent that affects Earth ecosystems and the human population. As a primary consequence of the stratospheric ozone layer depletion observed over the last decades, the increasing UV incidence levels have heightened the concern regarding deleterious consequences affecting both the biosphere and humans, thereby leading to an increase in scientific efforts to understand the role of sunlight in the induction of DNA damage, mutagenesis, and cell death. In fact, the various UV-wavelengths evoke characteristic biological impacts that greatly depend on light absorption of biomolecules, especially DNA, in living organisms, thereby justifying the increasing importance of developing biological sensors for monitoring the harmful impact of solar UV radiation under various environmental conditions. In this review, several types of biosensors proposed for laboratory and field application, that measure the biological effects of the UV component of sunlight, are described. Basically, the applicability of sensors based on DNA, bacteria or even mammalian cells are presented and compared. Data are also presented showing that on using DNA-based sensors, the various types of damage produced differ when this molecule is exposed in either an aqueous buffer or a dry solution. Apart from the data thus generated, the development of novel biosensors could help in evaluating the biological effects of sunlight on the environment. They also emerge as alternative tools for using live animals in the search for protective sunscreen products. PMID:22163847

Field measurements of temperature profile for floatovoltaic dryer in the tropics

NASA Astrophysics Data System (ADS)

Osman, F. A.; Ya'acob, M. E.; Iskandar, A. Noor

2017-09-01

Most of the equator region in a tropical climate zone experiences hot and humid weather but sometimes heavy rain and thunderstorms which occur stochastically in monsoon season. Sunlight which is the energy source can be harvested approximately 8 hours (on average basis) daily throughout the year which leads to the promotion of Solar PV technologies. This works projects the field performance for a new Floatovoltaic Dryer prototype with flexible PV roofing structures covering the top of the dryer system. The field measurements are collected on the lake of Engineering Faculty, UPM supported with 4-parameter weather station. Temperature profile with RH measurements inside the Floatovoltaic Dryer compartments as compared to direct-sun drying mechanism are the main contributions of this work and it projects more than 12 W of convection heat energy could be harvested by using the clean system. The field measurements imply various points of thermocouple and humidity sensor throughout the experiment. Temperature and humidity will be the main elements recorded to analyze the differences under monocrystalline PV panel as compared to natural drying.

Developments in the Disposal of Residue from the Alumina Refining Industry

NASA Astrophysics Data System (ADS)

Cooling, D. J.

The disposal of residue forms an integral part of the alumina refining process. The refining of Western Australia bauxite, which is low grade ore by world standards, results in 2 dry tonnes of residue for every 1 tonne of alumina produced. The disposal of this residue contributes a significant proportion of the overall cost of producing alumina. The residue is also highly alkaline, and, if not contained in sealed impoundment areas, can impact on the local environment. It has been these two considerations, the cost of disposal and the potential impact of disposal on the environment, which have been the main driving forces behind changes to the way residue is stored. This paper traces the various residue disposal techniques adopted by Alcoa of Australia Limited from containment in large settling ponds, to splitting the coarse and fine fractions for separate disposal, to the storage of the fine mud fraction in base drained ponds, to the more recent pre-thickening of the fine mud fraction for disposal in solar drying ponds. The reasons for change and the problems encountered are reviewed, and possible future developments are discussed.

Microorganisms in desert rocks: the edge of life on Earth.

PubMed

Wierzchos, Jacek; de los Ríos, Asunción; Ascaso, Carmen

2012-12-01

This article reviews current knowledge on microbial communities inhabiting endolithic habitats in the arid and hyper-arid regions of our planet. In these extremely dry environments, the most common survival strategy is to colonize the interiors of rocks. This habitat provides thermal buffering, physical stability, and protection against incident UV radiation, excessive photosynthetically active radiation, and freeze-thaw events. Above all, through water retention in the rocks' network of pores and fissures, moisture is made available. Some authors have argued that dry environments pose the most extreme set of conditions faced by microorganisms. Microbial cells need to withstand the biochemical stresses created by the lack of water, along with temperature fluctuations and/or high salinity. In this review, we also address the variety of ways in which microorganisms deal with the lack of moisture in hyper-arid environments and point out the diversity of microorganisms that are able to cope with only the scarcest presence of water. Finally, we discuss the important clues to the history of life on Earth, and perhaps other places in our solar system, that have emerged from the study of extreme microbial ecosystems.

Asynchronous Amazon forest canopy phenology indicates adaptation to both water and light availability

NASA Astrophysics Data System (ADS)

Jones, Matthew O.; Kimball, John S.; Nemani, Ramakrishna R.

2014-12-01

Amazon forests represent nearly half of all tropical vegetation biomass and, through photosynthesis and respiration, annually process more than twice the amount of estimated carbon (CO2) from fossil fuel emissions. Yet the seasonality of Amazon canopy cover, and the extent to which seasonal fluctuations in water availability and photosynthetically available radiation influence these processes, is still poorly understood. Implementing six remotely sensed data sets spanning nine years (2003-2011), with reported field and flux tower data, we show that southern equatorial Amazon forests exhibit a distinctive seasonal signal. Seasonal timing of water availability, canopy biomass growth and net leaf flush are asynchronous in regions with short dry seasons and become more synchronous across a west-to-east longitudinal moisture gradient of increasing dry season. Forest cover is responsive to seasonal disparities in both water and solar radiation availability, temporally adjusting net leaf flush to maximize use of these generally abundant resources, while reducing drought susceptibility. An accurate characterization of this asynchronous behavior allows for improved understanding of canopy phenology across contiguous tropical forests and their sensitivity to climate variability and drought.

Three decades of reference evapotranspiration estimates for a tropical watershed in the eastern Amazon.

PubMed

Silva, Renato O DA; Souza, Everaldo B DE; Tavares, Alexandra L; Mota, José A; Ferreira, Douglas B S; Souza-Filho, Pedro W M; Rocha, Edson J P DA

2017-01-01

This study estimated the reference evapotranspiration rate (ETo) for the Itacaiúnas River Watershed (IRW), Eastern Amazonia, and measured the accuracy of eight empirical equations: Penman-Monteith (PM), Priestley-Taylor (PT), Hargreaves and Samani (HS), Camargo (CAM), Thornthwaite (TH), Hamon (HM), Kharrufa (KF) and Turc (TC) using monthly data from 1980 to 2013. In addition, it verifies the regional applicability to the IRW using a for the Marabá-PA station. The methods TC and PM (FAO56) presented the best results, which demonstrate that radiation and higher temperatures are the dominant drivers in the Evapotranspiration process, while relative humidity and wind speed have a much smaller impact. The temporal and spatial variability of ETo for IRW show has strong seasonality, increasing during the dry season and decreasing during the rainy season. The statistical analyses at 1% level of significance, indicates that there is no correlation of the residuals between the dry and rainy seasons, and test of the physical parameters such as mean temperature, solar radiation and relative air humidity explains the variations of ETo.

Hydrologic and micrometeorologic data from an unsaturated zone study at a low-level radioactive waste burial site near Barnwell, South Carolina

USGS Publications Warehouse

Dennehy, K.F.; McMahon, P.B.

1985-01-01

Two years of selected hydrologic and micrometeorologic data collected at a low-level radioactive waste burial site near Barnwell, South Carolina are available on magnetic tape in card-image format. Hydrologic data include daily measurements of soil-moisture tension, soil-moisture specific conductance, and soil temperature at four monitoring site locations. Micrometeorlogic data include hourly measurements for the following parameters: dry- and wet-bulb temperatures, soil temperatures, soil heat flux, wind speeds and direction, incoming and reflected short-wave solar radiation, incoming and emitted long-wave radiation, net radiation and precipitation. (USGS)

Pathfinder aircraft flight #1

NASA Image and Video Library

1996-11-19

The Pathfinder solar-powered research aircraft settles in for landing on the bed of Rogers Dry Lake at the Dryden Flight Research Center, Edwards, California, after a successful test flight Nov. 19, 1996. The ultra-light craft flew a racetrack pattern at low altitudes over the flight test area for two hours while project engineers checked out various systems and sensors on the uninhabited aircraft. The Pathfinder was controlled by two pilots, one in a mobile control unit which followed the craft, the other in a stationary control station. Pathfinder, developed by AeroVironment, Inc., is one of several designs being evaluated under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program.

An investigation of surface albedo variations during the recent sahel drought. [ats 3 observations

NASA Technical Reports Server (NTRS)

Norton, C. C.; Mosher, F. R.; Hinton, B.

1978-01-01

Applications Technology Satellite 3 green sensor data were used to measure surface reflectance variations in the Sahara/Sahel during the recent drought period; 1967 to 1974. The magnitude of the seasonal reflectance change is shown to be as much as 80% for years of normal precipitation and less than 50% for drought years. Year to year comparisons during both wet and dry seasons reveal the existence of a surface reflectance cycle coincident with the drought intensity. The relationship between the green reflectance and solar albedo is examined and estimated to be about 0.6 times the reflectance change observed by the green channel.

Combinatorial screening of halide perovskite thin films and solar cells by mask-defined IR laser molecular beam epitaxy

NASA Astrophysics Data System (ADS)

Kawashima, Kazuhiro; Okamoto, Yuji; Annayev, Orazmuhammet; Toyokura, Nobuo; Takahashi, Ryota; Lippmaa, Mikk; Itaka, Kenji; Suzuki, Yoshikazu; Matsuki, Nobuyuki; Koinuma, Hideomi

2017-12-01

As an extension of combinatorial molecular layer epitaxy via ablation of perovskite oxides by a pulsed excimer laser, we have developed a laser molecular beam epitaxy (MBE) system for parallel integration of nano-scaled thin films of organic-inorganic hybrid materials. A pulsed infrared (IR) semiconductor laser was adopted for thermal evaporation of organic halide (A-site: CH3NH3I) and inorganic halide (B-site: PbI2) powder targets to deposit repeated A/B bilayer films where the thickness of each layer was controlled on molecular layer scale by programming the evaporation IR laser pulse number, length, or power. The layer thickness was monitored with an in situ quartz crystal microbalance and calibrated against ex situ stylus profilometer measurements. A computer-controlled movable mask system enabled the deposition of combinatorial thin film libraries, where each library contains a vertically homogeneous film with spatially programmable A- and B-layer thicknesses. On the composition gradient film, a hole transport Spiro-OMeTAD layer was spin-coated and dried followed by the vacuum evaporation of Ag electrodes to form the solar cell. The preliminary cell performance was evaluated by measuring I-V characteristics at seven different positions on the 12.5 mm × 12.5 mm combinatorial library sample with seven 2 mm × 4 mm slits under a solar simulator irradiation. The combinatorial solar cell library clearly demonstrated that the energy conversion efficiency sharply changes from nearly zero to 10.2% as a function of the illumination area in the library. The exploration of deposition parameters for obtaining optimum performance could thus be greatly accelerated. Since the thickness ratio of PbI2 and CH3NH3I can be freely chosen along the shadow mask movement, these experiments show the potential of this system for high-throughput screening of optimum chemical composition in the binary film library and application to halide perovskite solar cell.

Water recovery in a concentrated solar power plant

NASA Astrophysics Data System (ADS)

Raza, Aikifa; Higgo, Alex R.; Alobaidli, Abdulaziz; Zhang, TieJun

2016-05-01

For CSP plants, water consumption is undergoing increasing scrutiny particularly in dry and arid regions with water scarcity conditions. Significant amount of water has to be used for parabolic trough mirror cleaning to maintain high mirror reflectance and optical efficiency in sandy environment. For this specific purpose, solar collectors are washed once or twice every week at Shams 1, one of the largest CSP plant in the Middle East, and about 5 million gallons of demineralized water is utilized every year without further recovery. The produced waste water from a CSP plant contains the soiling i.e. accumulated dust and some amount of organic contaminants, as indicated by our analysis of waste water samples from the solar field. We thus need to develop a membrane based system to filter fine dust particulates and to degrade organic contaminant simultaneously. Membrane filtration technology is considered to be cost-effective way to address the emerging problem of a clean water shortage, and to reuse the filtered water after cleaning solar collectors. But there are some major technical barriers to improve the robustness and energy efficiency of filtration membranes especially when dealing with the removal of ultra-small particles and oil traces. Herein, we proposed a robust and scalable nanostructured inorganic microporous filtration copper mesh. The inorganic membrane surface wettability is tailored to enhance the water permeability and filtration flux by creating nanostructures. These nanostructured membranes were successfully employed to recover water collected after cleaning the reflectors of solar field of Shams 1. Another achievement was to remove the traces of heat transfer fluid (HTF) from run-off water which was collected after accidental leakage in some of the heat exchangers during the commissioning of the Shams 1 for safe disposal into the main stream. We hope, by controlling the water recovery factor and membrane reusability performance, the membrane design could be used for water conservation in CSP plants.

Effects of Solar Geoengineering on Meridional Energy Transport and the ITCZ

NASA Astrophysics Data System (ADS)

Russotto, R. D.; Ackerman, T. P.; Frierson, D. M.

2016-12-01

The polar amplification of warming and the ability of the intertropical convergence zone (ITCZ) to shift to the north or south are two very important problems in climate science. Examining these behaviors in global climate models (GCMs) running solar geoengineering experiments is helpful not only for predicting the effects of solar geoengineering, but also for understanding how these processes work under increased CO2. Both polar amplification and ITCZ shifts are closely related to the meridional transport of moist static energy (MSE) by the atmosphere. In this study we examine changes in MSE transport in 10 fully coupled GCMs in Experiment G1 of the Geoengineering Model Intercomparison Project, in which the solar constant is reduced to compensate for abruptly quadrupled CO2 concentrations. In this experiment, poleward MSE transport decreases relative to preindustrial conditions in all models, in contrast to the CMIP5 abrupt4xCO2 experiment, in which poleward MSE transport increases. The increase in poleward MSE transport under increased CO2 is due to latent heat transport, as specific humidity increases faster in the tropics than at the poles; this mechanism is not present under G1 conditions, so the reduction in dry static energy transport due to a weakened equator-to-pole temperature gradient leads to weaker energy transport overall. Changes in cross-equatorial MSE transport in G1, meanwhile, are anticorrelated with shifts in the ITCZ. The northward ITCZ shift in G1 is 0.14 degrees in the multi-model mean and ranges from -0.33 to 0.89 degrees between the models. We examine the specific forcing and feedback terms responsible for changes in MSE transport in G1 by running experiments with a moist energy balance model. This work will help identify the largest sources of uncertainty regarding ITCZ shifts under solar geoengineering, and will help improve our understanding of the reasons for the residual polar amplification that occurs in the G1 experiment.

Combinatorial screening of halide perovskite thin films and solar cells by mask-defined IR laser molecular beam epitaxy.

PubMed

Kawashima, Kazuhiro; Okamoto, Yuji; Annayev, Orazmuhammet; Toyokura, Nobuo; Takahashi, Ryota; Lippmaa, Mikk; Itaka, Kenji; Suzuki, Yoshikazu; Matsuki, Nobuyuki; Koinuma, Hideomi

2017-01-01

As an extension of combinatorial molecular layer epitaxy via ablation of perovskite oxides by a pulsed excimer laser, we have developed a laser molecular beam epitaxy (MBE) system for parallel integration of nano-scaled thin films of organic-inorganic hybrid materials. A pulsed infrared (IR) semiconductor laser was adopted for thermal evaporation of organic halide (A-site: CH 3 NH 3 I) and inorganic halide (B-site: PbI 2 ) powder targets to deposit repeated A/B bilayer films where the thickness of each layer was controlled on molecular layer scale by programming the evaporation IR laser pulse number, length, or power. The layer thickness was monitored with an in situ quartz crystal microbalance and calibrated against ex situ stylus profilometer measurements. A computer-controlled movable mask system enabled the deposition of combinatorial thin film libraries, where each library contains a vertically homogeneous film with spatially programmable A- and B-layer thicknesses. On the composition gradient film, a hole transport Spiro-OMeTAD layer was spin-coated and dried followed by the vacuum evaporation of Ag electrodes to form the solar cell. The preliminary cell performance was evaluated by measuring I - V characteristics at seven different positions on the 12.5 mm × 12.5 mm combinatorial library sample with seven 2 mm × 4 mm slits under a solar simulator irradiation. The combinatorial solar cell library clearly demonstrated that the energy conversion efficiency sharply changes from nearly zero to 10.2% as a function of the illumination area in the library. The exploration of deposition parameters for obtaining optimum performance could thus be greatly accelerated. Since the thickness ratio of PbI 2 and CH 3 NH 3 I can be freely chosen along the shadow mask movement, these experiments show the potential of this system for high-throughput screening of optimum chemical composition in the binary film library and application to halide perovskite solar cell.

Solar Spectral Radiative Forcing During the Southern African Regional Science Initiative

NASA Technical Reports Server (NTRS)

Pilewskie, P.; Pommier, J.; Bergstrom, R.; Gore, W.; Howard, S.; Rabbette, M.; Schmid, B.; Hobbs, P. V.; Tsay, S. C.

2003-01-01

During the dry season component of the Southern African Regional Science Initiative (SAFARI) in late winter 2000, the net solar spectral irradiance was measured at flight levels throughout biomass burning haze layers. From these measurements, the flux divergence, fractional absorption, instantaneous heating rate, and absorption efficiency were derived. Two cases are examined: on 24 August 2000 off the coast of Mozambique in the vicinity of Inhaca Island and on 6 September 2000 in a very thick continental haze layer over Mongu, Zambia. The measured absolute absorption was substantially higher for the case over Mongu where the measured midvisible optical depth exceeded unity. Instantaneous heating from aerosol absorption was 4 K d(sup -1) over Mongu, Zambia and 1.5 K d(sup -1) near Inhaca Island, Mozambique. However, the spectral absorption efficiency was nearly identical for both cases. Although the observations over Inhaca Island preceded the river of smoke from the southern African continent by nearly 2 weeks, the evidence here suggests a continental influence in the lower tropospheric aerosol far from source regions of burning.

Self-assembled photosystem-I biophotovoltaics on nanostructured TiO(2 )and ZnO.

PubMed

Mershin, Andreas; Matsumoto, Kazuya; Kaiser, Liselotte; Yu, Daoyong; Vaughn, Michael; Nazeeruddin, Md K; Bruce, Barry D; Graetzel, Michael; Zhang, Shuguang

2012-01-01

The abundant pigment-protein membrane complex photosystem-I (PS-I) is at the heart of the Earth's energy cycle. It is the central molecule in the "Z-scheme" of photosynthesis, converting sunlight into the chemical energy of life. Commandeering this intricately organized photosynthetic nanocircuitry and re-wiring it to produce electricity carries the promise of inexpensive and environmentally friendly solar power. We here report that dry PS-I stabilized by surfactant peptides functioned as both the light-harvester and charge separator in solar cells self-assembled on nanostructured semiconductors. Contrary to previous attempts at biophotovoltaics requiring elaborate surface chemistries, thin film deposition, and illumination concentrated into narrow wavelength ranges the devices described here are straightforward and inexpensive to fabricate and perform well under standard sunlight yielding open circuit photovoltage of 0.5 V, fill factor of 71%, electrical power density of 81 µW/cm(2) and photocurrent density of 362 µA/cm(2), over four orders of magnitude higher than any photosystem-based biophotovoltaic to date.

Self-assembled photosystem-I biophotovoltaics on nanostructured TiO2 and ZnO

PubMed Central

Mershin, Andreas; Matsumoto, Kazuya; Kaiser, Liselotte; Yu, Daoyong; Vaughn, Michael; Nazeeruddin, Md. K.; Bruce, Barry D.; Graetzel, Michael; Zhang, Shuguang

2012-01-01

The abundant pigment-protein membrane complex photosystem-I (PS-I) is at the heart of the Earth’s energy cycle. It is the central molecule in the “Z-scheme” of photosynthesis, converting sunlight into the chemical energy of life. Commandeering this intricately organized photosynthetic nanocircuitry and re-wiring it to produce electricity carries the promise of inexpensive and environmentally friendly solar power. We here report that dry PS-I stabilized by surfactant peptides functioned as both the light-harvester and charge separator in solar cells self-assembled on nanostructured semiconductors. Contrary to previous attempts at biophotovoltaics requiring elaborate surface chemistries, thin film deposition, and illumination concentrated into narrow wavelength ranges the devices described here are straightforward and inexpensive to fabricate and perform well under standard sunlight yielding open circuit photovoltage of 0.5 V, fill factor of 71%, electrical power density of 81 µW/cm2 and photocurrent density of 362 µA/cm2, over four orders of magnitude higher than any photosystem-based biophotovoltaic to date. PMID:22355747

Hourly global and diffuse radiation of Lagos, Nigeria-correlation with some atmospheric parameters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chendo, M.A.C.; Maduekwe, A.A.L.

1994-03-01

The influence of four climatic parameters on the hourly diffuse fraction in Lagos, Nigeria, has been studied. Using data for two years, new correlations were established. The standard error of the Liu and Jordan-type equation was reduced by 12.83% when solar elevation, ambient temperature, and relative humidity were used together as predictor variables for the entire data set. Ambient temperature and relative humidity proved to be very important variables for predicting the diffuse fraction of the solar radiation passing through the humid atmosphere of the coastal and tropic city of Lagos. Seasonal analysis carried out with the data showed improvementsmore » on the standard errors for the new seasonal correlations. In the case of the dry season, the improvement was 18.37%, whole for the wet season, this was 12.37%. Comparison with existing correlations showed that the performance of the one parameter model (namely K[sub t]), of Orgill and Hollands and Reindl, Beckman, and Duffie were very different from the Liu and Jordan-type model obtained for Lagos.« less

Ultraviolet radiation and bio-optics in Crater Lake, Oregon

USGS Publications Warehouse

Hargreaves, B.R.; Girdner, S.F.; Buktenica, M.W.; Collier, R.W.; Urbach, E.; Larson, G.L.

2007-01-01

Crater Lake, Oregon, is a mid-latitude caldera lake famous for its depth (594 m) and blue color. Recent underwater spectral measurements of solar radiation (300-800 nm) support earlier observations of unusual transparency and extend these to UV-B wavelengths. New data suggest that penetration of solar UVR into Crater Lake has a significant ecological impact. Evidence includes a correlation between water column chlorophyll-a and stratospheric ozone since 1984, the scarcity of organisms in the upper water column, and apparent UV screening pigments in phytoplankton that vary with depth. The lowest UV-B diffuse attenuation coefficients (K d,320) were similar to those reported for the clearest natural waters elsewhere, and were lower than estimates for pure water published in 1981. Optical proxies for UVR attenuation were correlated with chlorophyll-a concentration (0-30 m) during typical dry summer months from 1984 to 2002. Using all proxies and measurements of UV transparency, decadal and longer cycles were apparent but no long-term trend since the first optical measurement in 1896. ?? 2007 Springer Science+Business Media B.V.

Effect of Solar Ultraviolet-B Radiation during Springtime Ozone Depletion on Photosynthesis and Biomass Production of Antarctic Vascular Plants1

PubMed Central

Xiong, Fusheng S.; Day, Thomas A.

2001-01-01

We assessed the influence of springtime solar UV-B radiation that was naturally enhanced during several days due to ozone depletion on biomass production and photosynthesis of vascular plants along the Antarctic Peninsula. Naturally growing plants of Colobanthus quitensis (Kunth) Bartl. and Deschampsia antarctica Desv. were potted and grown under filters that absorbed or transmitted most solar UV-B. Plants exposed to solar UV-B from mid-October to early January produced 11% to 22% less total, as well as above ground biomass, and 24% to 31% less total leaf area. These growth reductions did not appear to be associated with reductions in photosynthesis per se: Although rates of photosynthetic O2 evolution were reduced on a chlorophyll and a dry-mass basis, on a leaf area basis they were not affected by UV-B exposure. Leaves on plants exposed to UV-B were denser, probably thicker, and had higher concentrations of photosynthetic and UV-B absorbing pigments. We suspect that the development of thicker leaves containing more photosynthetic and screening pigments allowed these plants to maintain their photosynthetic rates per unit leaf area. Exposure to UV-B led to reductions in quantum yield of photosystem II, based on fluorescence measurements of adaxial leaf surfaces, and we suspect that UV-B impaired photosynthesis in the upper mesophyll of leaves. Because the ratio of variable to maximal fluorescence, as well as the initial slope of the photosynthetic light response, were unaffected by UV-B exposure, we suggest that impairments in photosynthesis in the upper mesophyll were associated with light-independent enzymatic, rather than photosystem II, limitations. PMID:11161031

Organism/Organic Exposure to Orbital Stresses (OOREOS) Satellite: Radiation Exposure in LEO and Supporting Laboratory Studies

NASA Technical Reports Server (NTRS)

Mattioda, Andrew Lige; Cook, Amanda Marie; Quinn, Richard C.; Elsaesser, Andreas; Ehrenfreund, Pascale; Ricca,Alessandra; Jones, Nykola C.; Hoffman, Soren; Ricco,Antonio

2014-01-01

We will present the results from the exposure of the metalloporphyrin iron tetraphenylporphyrin chloride (FeTPPCI), anthraufin (C(sub 14)H(sub 8)(O sub 4) (Anth) and Isoviolanthrene (C(sub 34H sub 18) (IVA) to the outher space environment, measured in situ aboard the Organism/Organic Exposure to Orbital Stresses nanosatellite. The compounds were exposed for a period of 17 months (3700 hours of direct solar exposure) including broad-spectrum solar radiation (approx. 122 nm to the near infrared). The organic films are enclosed in hermetically sealed sample cells that contain one of four astrobiologically relevant microenvironments. Transmission spectra (200-1000 nm) were recorded for each film, at first daily and subsequently every 15 days, along with a solar spectrum and the dark response of the detector array. In addition to analysis via UV-Vis spectroscopy, the laboratory controls were also monitored via infrared and far-UV spectroscopy. The results presented will include the finding that the FeTPPCI and IVA organic films in contact with a humid headspace gas (0.8-2.3%) exhibit faster degradation times, upon irradiation, in comparison with identical films under dry headspaces gases, whereas the Anth thin film exhibited a higher degree of photostability. In the companion laboratory experiments, simulated solar exposure of FeTPI films in contact with either Ar or CO(sub -2):O(sub -2):Ar (10:0.01:1000) headspace gas results in growth of a band in the films infrared spectra at 1961 cm(sup 1). Our assignment of this new spectral feature and the corresponding rational will be presented. The relevance of O/OREOS findings to planetary science, biomarker research, and the photostability of organic materials in astrobiologically relevant environments will also be discussed.

Effect of Solar Radiation on Viscoelastic Properties of Bovine Leather: Temperature and Frequency Scans

NASA Astrophysics Data System (ADS)

Nalyanya, Kallen Mulilo; Rop, Ronald K.; Onyuka, Arthur S.

2017-04-01

This work presents both analytical and experimental results of the effect of unfiltered natural solar radiation on the thermal and dynamic mechanical properties of Boran bovine leather at both pickling and tanning stages of preparation. Samples cut from both pickled and tanned pieces of leather of appropriate dimensions were exposed to unfiltered natural solar radiation for time intervals ranging from 0 h (non-irradiated) to 24 h. The temperature of the dynamic mechanical analyzer was equilibrated at 30°C and increased to 240°C at a heating rate of 5°C \\cdot Min^{-1}, while its oscillation frequency varied from 0.1 Hz to 100 Hz. With the help of thermal analysis (TA) control software which analyzes and generates parameter means/averages at temperature/frequency range, the graphs were created by Microsoft Excel 2013 from the means. The viscoelastic properties showed linear frequency dependence within 0.1 Hz to 30 Hz followed by negligible frequency dependence above 30 Hz. Storage modulus (E') and shear stress (σ ) increased with frequency, while loss modulus (E''), complex viscosity (η ^{*}) and dynamic shear viscosity (η) decreased linearly with frequency. The effect of solar radiation was evident as the properties increased initially from 0 h to 6 h of irradiation followed by a steady decline to a minimum at 18 h before a drastic increase to a maximum at 24 h. Hence, tanning industry can consider the time duration of 24 h for sun-drying of leather to enhance the mechanical properties and hence the quality of the leather. At frequencies higher than 30 Hz, the dynamic mechanical properties are independent of the frequency. The frequency of 30 Hz was observed to be a critical value in the behavior in the mechanical properties of bovine hide.

Performance of a solar augmented heat pump

NASA Astrophysics Data System (ADS)

Bedinger, A. F. G.; Tomlinson, J. J.; Reid, R. L.; Chaffin, D. J.

Performance of a residential size solar augmented heat pump is reported for the 1979-1980 heating season. The facility located in Knoxville, Tennessee, has a measured heat load coefficient of 339.5 watt/C (644 BTU/hr- F). The solar augmented heat pump system consists of 7.4 cu m of one inch diameter crushed limestone. The heat pump is a nominal 8.8 KW (2 1/2 ton) high efficiency unit. The system includes electric resistance heaters to give the option of adding thermal energy to the pebble bed storage during utility off-peak periods, thus offering considerable load management capability. A 15 KW electric resistance duct heater is used to add thermal energy to the pebble bin as required during off-peak periods. Hourly thermal performance and on site weather data was taken for the period November 1, 1979, to April 13, 1980. Thermal performance data consists of heat flow summations for all modes of the system, pebble bed temperatures, and space temperature. Weather data consists of dry bulb temperature, dew point temperature, total global insolation (in the plane of the collector), and wind speed and direction. An error analysis was performed and the least accurate of the measurements was determined to be the heat flow at 5%. Solar system thermal performance factor was measured to be 8.77. The heat pump thermal performance factor was 1.64. Total system seasonal performance factor was measured to be 1.66. Using a modified version of TRNSYS, the thermal performance of this system was simulated. When simulation results were compared with data collected onsite, the predicted heat flow and power consumption generally were within experimental accuracy.

Irradiance optimization of outdoor microalgal cultures using solar tracked photobioreactors.

PubMed

Hindersin, Stefan; Leupold, Marco; Kerner, Martin; Hanelt, Dieter

2013-03-01

Photosynthetic activity and temperature regulation of microalgal cultures (Chlorella vulgaris and Scenedesmus obliquus) under different irradiances controlled by a solar tracker and different cell densities were studied in outdoor flat panel photobioreactors. An automated process control unit regulated light and temperature as well as pH value and nutrient concentration in the culture medium. CO2 was supplied using flue gas from an attached combined block heat and power station. Photosynthetic activity was determined by pulse amplitude modulation fluorometry. Compared to the horizontal irradiance of 55 mol photons m(-2) d(-1) on a clear day, the solar tracked photobioreactors enabled a decrease and increase in the overall light absorption from 19 mol photons m(-2) d(-1) (by rotation out of direct irradiance) to 79 mol photons m(-2) d(-1) (following the position of the sun). At biomass concentrations below 1.1 g cell dry weight (CDW) L(-1), photoinhibition of about 35 % occurred at irradiances of ≥1,000 μmol photons m(-2) s(-1) photosynthetic active radiation (PAR). Using solar tracked photobioreactors, photoinhibition can be reduced and at optimum biomass concentration (≥2.3 g CDW L(-1)), the culture was irradiated up to 2,000 μmol photons m(-2) s(-1) to overcome light limitation with biomass yields of 0.7 g CDW mol photons(-1) and high photosynthetic activities indicated by an effective quantum yield of 0.68 and a maximum quantum yield of 0.80 (F v/F m). Overheating due to high irradiance was avoided by turning the PBR out of the sun or using a cooling system, which maintained the temperature close to the species-specific temperature optima.

Effect of solar ultraviolet-B radiation during springtime ozone depletion on photosynthesis and biomass production of Antarctic vascular plants.

PubMed

Xiong, F S; Day, T A

2001-02-01

We assessed the influence of springtime solar UV-B radiation that was naturally enhanced during several days due to ozone depletion on biomass production and photosynthesis of vascular plants along the Antarctic Peninsula. Naturally growing plants of Colobanthus quitensis (Kunth) Bartl. and Deschampsia antarctica Desv. were potted and grown under filters that absorbed or transmitted most solar UV-B. Plants exposed to solar UV-B from mid-October to early January produced 11% to 22% less total, as well as above ground biomass, and 24% to 31% less total leaf area. These growth reductions did not appear to be associated with reductions in photosynthesis per se: Although rates of photosynthetic O(2) evolution were reduced on a chlorophyll and a dry-mass basis, on a leaf area basis they were not affected by UV-B exposure. Leaves on plants exposed to UV-B were denser, probably thicker, and had higher concentrations of photosynthetic and UV-B absorbing pigments. We suspect that the development of thicker leaves containing more photosynthetic and screening pigments allowed these plants to maintain their photosynthetic rates per unit leaf area. Exposure to UV-B led to reductions in quantum yield of photosystem II, based on fluorescence measurements of adaxial leaf surfaces, and we suspect that UV-B impaired photosynthesis in the upper mesophyll of leaves. Because the ratio of variable to maximal fluorescence, as well as the initial slope of the photosynthetic light response, were unaffected by UV-B exposure, we suggest that impairments in photosynthesis in the upper mesophyll were associated with light-independent enzymatic, rather than photosystem II, limitations.

Synchronicity of the East Asian Summer Monsoon variability and Northern Hemisphere climate change since the last deglaciation

NASA Astrophysics Data System (ADS)

Shinozaki, T.; Uchida, M.; Minoura, K.; Kondo, M.; Rella, S. F.; Shibata, Y.

2011-06-01

Understanding of the mechanism of the East Asian Summer Monsoon (EASM) is required for the prediction of climate change in East Asia in a scenario of modern global warming. In this study, we present high-resolution climate records from peat sediments in Northeast Japan to reconstruct the EASM variability based on peat bulk cellulose δ13C since the last deglaciation. We used a 8.8 m long peat sediment core collected from the Tashiro Bog, Northeast Japan. Based on 42 14C measurements, the core bottom reaches ~15.5 ka. δ13C, accumulation rate and accumulation flux time-series correlate well to Greenland ice core δ18O variability, suggesting that the climate record in Northeast Japan is linked to global climate changes. The δ13C record at Tashiro Bog and other paleo-EASM records at Northeast and Southern China consistently demonstrate that hydrological environments were spatially different in mid-high and mid-low latitude regions over the last 15.5 kyr. During global cooling (warming) periods, mid-high and mid-low latitude regions were characterized by wet (dry) and dry (wet) environments, respectively. We suggest that these climatic patterns are related to the migration of the EASM-related rain belt during global climate changes, as a consequence of variations in intensity and location of both the Intertropical Convergence Zone (ITCZ) and the Western Pacific Subtropical High (STH). The location of the rain belt largely influences the East Asian hydrological environment. Our δ13C time-series are characterized by a 1230 yr throughout the Holocene and a 680 yr periodicity during the early Holocene. The 1230 yr periodicity is in agreement with North Atlantic ice-rafted debris (IRD) events, suggesting a teleconnection between the Northeast Japan and the North Atlantic during the Holocene. In addition, it is the first evidence that the Bond events were recorded in terrestrial sediment in Japan. On the other hand, the 680 yr periodicity between 10.0 and 8.0 kyr is consistent with a prominent 649 yr solar activity cycle, suggesting that solar activity affected EASM precipitation during the Hypsithermal, when orbital-scale solar insolation was at a maximum in the Northern Hemisphere.

Squiggles in Hellas Planitia

NASA Image and Video Library

2017-10-25

At around 2,200 kilometers in diameter, Hellas Planitia is the largest visible impact basin in the Solar System, and hosts the lowest elevations on Mars' surface as well as a variety of landscapes. This image from NASA's Mars Reconnaisance Orbiter (MRO) covers a small central portion of the basin and shows a dune field with lots of dust devil trails. In the middle, we see what appears to be long and straight "scratch marks" running down the southeast (bottom-right) facing dune slopes. If we look closer, we can see these scratch marks actually squiggle back and forth on their way down the dune. These scratch marks are linear gullies. Just like on Earth, high-latitude regions on Mars are covered with frost in the winter. However, the winter frost on Mars is made of carbon dioxide ice (dry ice) instead of water ice. We believe linear gullies are the result of this dry ice breaking apart into blocks, which then slide or roll down warmer sandy slopes, sublimating and carving as they go. The linear gullies exhibit exceptional sinuosity (the squiggle pattern) and we believe this to be the result of repeated movement of dry ice blocks in the same path, possibly in combination with different hardness or flow resistance of the sand within the dune slopes. Determining the specific process that causes the formation and evolution of sinuosity in linear gullies is a question scientists are still trying to answer. What do you think causes the squiggles? https://photojournal.jpl.nasa.gov/catalog/PIA22052

A worldwide analysis of trends in water-balance evapotranspiration

NASA Astrophysics Data System (ADS)

Ukkola, A. M.; Prentice, I. C.

2013-10-01

Climate change is expected to alter the global hydrological cycle, with inevitable consequences for freshwater availability to people and ecosystems. But the attribution of recent trends in the terrestrial water balance remains disputed. This study attempts to account statistically for both trends and interannual variability in water-balance evapotranspiration (ET), estimated from the annual observed streamflow in 109 river basins during "water years" 1961-1999 and two gridded precipitation data sets. The basins were chosen based on the availability of streamflow time-series data in the Dai et al. (2009) synthesis. They were divided into water-limited "dry" and energy-limited "wet" basins following the Budyko framework. We investigated the potential roles of precipitation, aerosol-corrected solar radiation, land use change, wind speed, air temperature, and atmospheric CO2. Both trends and variability in ET show strong control by precipitation. There is some additional control of ET trends by vegetation processes, but little evidence for control by other factors. Interannual variability in ET was overwhelmingly dominated by precipitation, which accounted on average for 54-55% of the variation in wet basins (ranging from 0 to 100%) and 94-95% in dry basins (ranging from 69 to 100%). Precipitation accounted for 45-46% of ET trends in wet basins and 80-84% in dry basins. Net atmospheric CO2 effects on transpiration, estimated using the Land-surface Processes and eXchanges (LPX) model, did not contribute to observed trends in ET because declining stomatal conductance was counteracted by slightly but significantly increasing foliage cover.

Discontinuous Inter-Granular Separations (DIGS) in the Gas Nitride Layer of ISS Race Rings

NASA Technical Reports Server (NTRS)

Figert, John; Dasgupta, Rajib; Martinez, James

2010-01-01

The starboard solar alpha rotary joint (SARJ) race ring on the International space station (ISS) failed due to severe spalling of the outer diameter, 45 degree (outer canted) nitrided surface. Subsequent analysis at NASA-KSC revealed that almost all of the debris generated due to the failure was nitrided 15-5 stainless steel. Subsequent analysis of the nitride control coupons (NCC) at NASA-JSC revealed the presence of discontinuous inter-granular separations (DIGS) in the gas nitride layer. These DIGS were present in the inter-granular networking located in the top 2 mils of the nitride layer. The manufacturer's specification requires the maximum white structure to be 0.0003 inches and intergranular networking below the allowable white structure depth to be cause for rejection; a requirement that the NCCs did not meet. Subsequent testing and analysis revealed that lower DIGS content significantly lowered the probability of nitride spalling in simulated, dry condition runs. One batch of nitride samples with DIGS content similar to the port SARJ (did not fail on orbit) which exhibited almost no nitride spalling after being run on one test rig. Another batch of nitride samples with DIGS content levels similar to the starboard SARJ exhibited significant nitride spalling on the same test rig with the same load under dry conditions. Although DIGS were not the root cause of starboard race ring failure, testing indicates that increased DIGS reduced the robustness of the gas nitride layer under dry operating conditions.

NNSS Soils Monitoring: Plutonium Valley (CAU 366) FY2015

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nikolich, George; Mizell, Steve; McCurdy, Greg

Desert Research Institute (DRI) is conducting a field assessment of the potential for contaminated soil transport from the Plutonium Valley Contamination Area (CA) as a result of wind transport and storm runoff in support of National Nuclear Security Administration (NNSA) efforts to complete regulatory closure of the contamination areas. The DRI work is intended to confirm the likely mechanism(s) of transport and determine the meteorological conditions that might cause movement of contaminated soils. The emphasis of the work is on collecting sediment transported by channelized storm runoff at the Plutonium Valley investigation sites. These data will inform closure plans thatmore » are being developed, which will facilitate the appropriate closure design and post-closure monitoring. In 2011, DRI installed two meteorological monitoring stations south (station #1) and north (station #2) of the Plutonium Valley CA and a runoff sediment sampling station within the CA. Temperature, wind speed, wind direction, relative humidity, precipitation, solar radiation, barometric pressure, soil temperature, and airborne particulate concentration are collected at both meteorological stations. The maximum, minimum, and average or total (as appropriate) for each of these parameters are recorded for each 10-minute interval. The sediment sampling station includes an automatically activated ISCO sampling pump with collection bottles for suspended sediment, which is activated when sufficient flow is present in the channel, and passive traps for bedload material that is transported down the channel during runoff events. This report presents data collected from these stations during fiscal year (FY) 2015.« less

Solar-powered Gossamer Penguin in flight

NASA Technical Reports Server (NTRS)

1979-01-01

Gossamer Penguin in flight above Rogers Dry Lakebed at Edwards, California, showing the solar panel perpendicular to the wing and facing the sun. Background The first flight of a solar-powered aircraft took place on November 4, 1974, when the remotely controlled Sunrise II, designed by Robert J. Boucher of AstroFlight, Inc., flew following a launch from a catapult. Following this event, AeroVironment, Inc. (founded in 1971 by the ultra-light airplane innovator--Dr. Paul MacCready) took on a more ambitious project to design a human-piloted, solar-powered aircraft. The firm initially took the human-powered Gossamer Albatross II and scaled it down to three-quarters of its previous size for solar-powered flight with a human pilot controlling it. This was more easily done because in early 1980 the Gossamer Albatross had participated in a flight research program at NASA Dryden in a program conducted jointly by the Langley and Dryden research centers. Some of the flights were conducted using a small electric motor for power. Gossamer Penguin The scaled-down aircraft was designated the Gossamer Penguin. It had a 71-foot wingspan compared with the 96-foot span of the Gossamer Albatross. Weighing only 68 pounds without a pilot, it had a low power requirement and thus was an excellent test bed for solar power. AstroFlight, Inc., of Venice, Calif., provided the power plant for the Gossamer Penguin, an Astro-40 electric motor. Robert Boucher, designer of the Sunrise II, served as a key consultant for both this aircraft and the Solar Challenger. The power source for the initial flights of the Gossamer Penguin consisted of 28 nickel-cadmium batteries, replaced for the solar-powered flights by a panel of 3,920 solar cells capable of producing 541 Watts of power. The battery-powered flights took place at Shafter Airport near Bakersfield, Calif. Dr. Paul MacCready's son Marshall, who was 13 years old and weighed roughly 80 pounds, served as the initial pilot for these flights to determine the power required to fly the airplane, optimize the airframe/propulsion system, and train the pilot. He made the first flights on April 7, 1980, and made a brief solar-powered flight on May 18. The official project pilot was Janice Brown, a Bakersfield school teacher who weighed in at slightly under 100 pounds and was a charter pilot with commercial, instrument, and glider ratings. She checked out in the plane at Shafter and made about 40 flights under battery and solar power there. Wind direction, turbulence, convection, temperature and radiation at Shafter in mid-summer proved to be less than ideal for Gossamer Penguin because takeoffs required no crosswind and increases in temperature reduced the power output from the solar cells. Consequently, the project moved to Dryden in late July, although conditions there also were not ideal. Nevertheless, Janice finished the testing, and on August 7, 1980, she flew a public demonstration of the aircraft at Dryden in which it went roughly 1.95 miles in 14 minutes and 21 seconds. This was significant as the first sustained flight of an aircraft relying solely on direct solar power rather than batteries. It provided the designers with practical experience for developing a more advanced, solar-powered aircraft, since the Gossamer Penguin was fragile and had limited controllability. This necessitated its flying early in the day when there were minimal wind and turbulence levels, but the angle of the sun was also low, requiring a panel for the solar cells that could be tilted toward the sun. Using the specific conclusions derived from their experience with Gossamer Penguin, the AeroVironment engineers designed Solar Challenger, a piloted, solar-powered aircraft strong enough to handle both long and high flights when encountering normal turbulence.

Centurion Quarter-scale Prototype Pre-flight Taxi Test

NASA Technical Reports Server (NTRS)

1997-01-01

As crewmen jog and cycle alongside, a battery-powered, quarter-scale prototype of the remotely-piloted Centurion flying wing rolls across the El Mirage Dry Lake during pre-flight taxi tests. Centurion was a unique remotely piloted, solar-powered airplane developed under NASA's Environmental Research Aircraft and Sensor (ERAST) Program at the Dryden Flight Research Center, Edwards, California. Dryden joined with AeroVironment, Inc., Monrovia, California, under an ERAST Joint Sponsored Research Agreement, to design, develop, manufacture, and conduct flight development tests for the Centurion. The airplane was believed to be the first aircraft designed to achieve sustained horizontal flight at altitudes of 90,000 to 100,000 feet. Achieving this capability would meet the ERAST goal of developing an ultrahigh-altitude airplane that could meet the needs of the science community to perform upper-atmosphere environmental data missions. Much of the technology leading to the Centurion was developed during the Pathfinder and Pathfinder-Plus projects. However, in the course of its development, the Centurion became a prototype technology demonstration aircraft designed to validate the technology for the Helios, a planned future high-altitude, solar-powered aircraft that could fly for weeks or months at a time on science or telecommunications missions. Centurion had 206-foot-long wings and used batteries to supply power to the craft's 14 electric motors and electronic systems. Centurion first flew at Dryden Nov. 10, 1998, and followed up with a second test flight Nov. 19. On its third and final flight on Dec. 3, the craft was aloft for 31 minutes and reached an altitude of about 400 feet. All three flights were conducted over a section of Rogers Dry Lake adjacent to Dryden. For its third flight, the Centurion carried a simulated payload of more than 600 pounds--almost half the lightweight aircraft's empty weight. John Del Frate, Dryden's project manager for solar-powered aircraft, said he was impressed to see how well the aircraft handled the large weight increase from an initial payload of 150 pounds to one of 600 pounds. During 1999, Centurion gave way to the Helios Prototype, the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions. This was an enlarged version of the Centurion flying wing with a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of the solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved its lifting capability. This allows the Helios Prototype to carry a regenerative fuel-cell-based energy storage system that will enable flight at night, while still meeting the performance goals originally established for the Centurion.

Centurion Quarter-scale Prototype Pre-flight Checkout

NASA Technical Reports Server (NTRS)

1997-01-01

Technicians perform pre-test checks of a battery-powered quarter-scale prototype of the remotely-piloted Centurion flying wing during taxi tests In March 1997 at California's El Mirage Dry Lake. Centurion was a unique remotely piloted, solar-powered airplane developed under NASA's Environmental Research Aircraft and Sensor (ERAST) Program at the Dryden Flight Research Center, Edwards, California. Dryden joined with AeroVironment, Inc., Monrovia, California, under an ERAST Joint Sponsored Research Agreement, to design, develop, manufacture, and conduct flight development tests for the Centurion. The airplane was believed to be the first aircraft designed to achieve sustained horizontal flight at altitudes of 90,000 to 100,000 feet. Achieving this capability would meet the ERAST goal of developing an ultrahigh-altitude airplane that could meet the needs of the science community to perform upper-atmosphere environmental data missions. Much of the technology leading to the Centurion was developed during the Pathfinder and Pathfinder-Plus projects. However, in the course of its development, the Centurion became a prototype technology demonstration aircraft designed to validate the technology for the Helios, a planned future high-altitude, solar-powered aircraft that could fly for weeks or months at a time on science or telecommunications missions. Centurion had 206-foot-long wings and used batteries to supply power to the craft's 14 electric motors and electronic systems. Centurion first flew at Dryden Nov. 10, 1998, and followed up with a second test flight Nov. 19. On its third and final flight on Dec. 3, the craft was aloft for 31 minutes and reached an altitude of about 400 feet. All three flights were conducted over a section of Rogers Dry Lake adjacent to Dryden. For its third flight, the Centurion carried a simulated payload of more than 600 pounds--almost half the lightweight aircraft's empty weight. John Del Frate, Dryden's project manager for solar-powered aircraft, said he was impressed to see how well the aircraft handled the large weight increase from an initial payload of 150 pounds to one of 600 pounds. During 1999, Centurion gave way to the Helios Prototype, the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions. This was an enlarged version of the Centurion flying wing with a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of the solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved its lifting capability. This allows the Helios Prototype to carry a regenerative fuel-cell-based energy storage system that will enable flight at night, while still meeting the performance goals originally established for the Centurion.

Centurion in Flight over Lakebed

NASA Technical Reports Server (NTRS)

1998-01-01

The Centurion remotely piloted flying wing during an early morning test flight over the Rogers Dry Lake adjacent to at NASA's Dryden Flight Research Center, Edwards, California. The flight was one of an initial series of low-altitude, battery-powered test flights conducted in late 1998. Centurion was a unique remotely piloted, solar-powered airplane developed under NASA's Environmental Research Aircraft and Sensor (ERAST) Program at the Dryden Flight Research Center, Edwards, California. Dryden joined with AeroVironment, Inc., Monrovia, California, under an ERAST Joint Sponsored Research Agreement, to design, develop, manufacture, and conduct flight development tests for the Centurion. The airplane was believed to be the first aircraft designed to achieve sustained horizontal flight at altitudes of 90,000 to 100,000 feet. Achieving this capability would meet the ERAST goal of developing an ultrahigh-altitude airplane that could meet the needs of the science community to perform upper-atmosphere environmental data missions. Much of the technology leading to the Centurion was developed during the Pathfinder and Pathfinder-Plus projects. However, in the course of its development, the Centurion became a prototype technology demonstration aircraft designed to validate the technology for the Helios, a planned future high-altitude, solar-powered aircraft that could fly for weeks or months at a time on science or telecommunications missions. Centurion had 206-foot-long wings and used batteries to supply power to the craft's 14 electric motors and electronic systems. Centurion first flew at Dryden Nov. 10, 1998, and followed up with a second test flight Nov. 19. On its third and final flight on Dec. 3, the craft was aloft for 31 minutes and reached an altitude of about 400 feet. All three flights were conducted over a section of Rogers Dry Lake adjacent to Dryden. For its third flight, the Centurion carried a simulated payload of more than 600 pounds--almost half the lightweight aircraft's empty weight. John Del Frate, Dryden's project manager for solar-powered aircraft, said he was impressed to see how well the aircraft handled the large weight increase from an initial payload of 150 pounds to one of 600 pounds. During 1999, Centurion gave way to the Helios Prototype, the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions. This was an enlarged version of the Centurion flying wing with a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of the solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved its lifting capability. This allows the Helios Prototype to carry a regenerative fuel-cell-based energy storage system that will enable flight at night, while still meeting the performance goals originally established for the Centurion.

Solar Orientation of Irish Early Christian Oratories

NASA Astrophysics Data System (ADS)

Tiede, V. R.

2001-12-01

The Hiberno-Latin literary metaphor of "Xpistus sol verus" (Christ the True Sun) finds an architectural analogue in the orientation of the single eastern window of Irish monastic stone chapels or oratories. The author's field surveys in Ireland, Hebrides, Orkney and Shetlands revealed that the window of Irish rectangular dry stone oratories framed the rising solar disk on the Feast Days of selected saints of the Celtic Early Christian Church, AD 800-1100. The most frequent target skyline declinations were to sunrise on the Feast Days of St. Patrick (March 17th) and St. Aidan of Lindisfarne (August 31st). During the Early Christian period, St. Patrick's Day coincided with the Vernal Equinox, and heralded the Paschal Full Moon (i.e., Passover crucifixion) and Easter Sunday as proclaimed by Emperor Constantine at the Council of Nicaea (AD 325). St. Aidan of Lindisfarne (d. AD 651) inspired the Irish monks who, at the Synod of Whitby (AD 664), remained loyal to the Jewish 84-year cycle determining Passover and refused to replace it with the new orthodox 19-year computus for Easter adopted by the Roman Catholic Church (AD 527). Hypothetical affiliation between monastic communities whose oratories share common solar orientation, interior length/width ratios (e.g., 4:3 and 3:2) and units of measurement (e.g., Scottish ell, Coptic cubit, or Roman pes) is discussed. Grateful acknowledgement is made to the Michael D. Coe Fund and Augusta Hazard Fund of Yale University for research grant support in 1999.

The long term trend of carbon dioxide and solar-induced chlorophyll fluorescence over selected sites using GOSAT target observation data

NASA Astrophysics Data System (ADS)

Kataoka, F.; Higuchi, R.; Kuze, A.; Shiomi, K.

2017-12-01

The Greenhouse gases Observing SATellite (GOSAT) is designed to measure the concentration of major greenhouse gases from space. GOSAT carry the Fourier-Transform Spectrometer, which have three shortwave infrared (SWIR) bands and one thermal infrared (TIR) band. The SWIR bands correspond to the O2A band (0.76 mm), weak-CO2 (1.6 mm) and strong-CO2 (2.0 mm). The SWIR bands observe the backscattered sunlight from surface and retrieve the column-averaged dry air mole fraction of carbon dioxide and methane. The 0.76 mm band can also detect the solar-induced chlorophyll fluorescence (SIF) using high spectral-resolution spectra in O2A band and solar absorption feature (Fraunhofer lines). GOSAT have operated more than 8 years and targeted various kinds of land-cover area (forest, grass, desert, etc.). The long term CO2 and SIF data set potential to address the rate of CO2 uptake through plant photosynthesis. In this work, we evaluated a trend and seasonal fluctuation components of CO2 and SIF using the liner and trigonometric functions fitting. We analyzed the amplitude and phase of the CO2 and SIF seasonal variation and anomalies over selected sites. Spatial distribution from target observation dataset which consist of 16 point per site using an agile pointing system over megacity is presented together with wind data. The data is available from the GOSAT trend viewer at http://www.eorc.jaxa.jp/GOSAT/CO2_monitor/.

Solar geoengineering could substantially reduce climate risks—A research hypothesis for the next decade

NASA Astrophysics Data System (ADS)

Keith, David W.; Irvine, Peter J.

2016-11-01

We offer a hypothesis that if solar geoengineering (SG) were deployed to offset half of the increase in global-mean temperature from the date of deployment using a technology and deployment method chosen to approximate a reduction in the solar constant then, over the 21st century, it would (a) substantially reduce the global aggregate risks of climate change, (b) without making any country worse off, and (c) with the aggregate risks from side-effects being small in comparison to the reduction in climate risks. We do not set out to demonstrate this hypothesis; rather we propose it with the goal of stimulating a strategic engagement of the SG research community with policy-relevant questions. We elaborate seven sub-hypotheses on the effects of our scenario for key risks of climate change that could be assessed in future modeling work. As an example, we provide a defence of one of our sub-hypotheses, that our scenario of SG would reduce the risk of drought in dry regions, but also identify issues that may undermine this sub-hypothesis and how future work could resolve this question. SG cannot substitute for emissions mitigation but it may be a useful supplement. It is our hope that scientific and technical research over the next decade focuses more closely on well-articulated variants of the key policy-relevant question: could SG be designed and deployed in such a way that it could substantially and equitably reduce climate risks?

Joint influence of the Indo-Pacific Warm Pool and Northern Arabian Sea Temperatures on the Indian Summer Monsoon in a Global Climate Model Simulation

NASA Astrophysics Data System (ADS)

Befort, Daniel J.; Leckebusch, Gregor C.; Cubasch, Ulrich

2016-04-01

Proxy-based studies confirmed that the Indian Summer Monsoon (ISM) shows large variations during the Holocene. These changes might be explained by changes in orbital conditions and solar insolation but are also thought to be associated to changes in oceanic conditions, e.g. over the Indo-Pacific-Warm-Pool region. However, due to the nature of these (proxy-based) analyses no conclusion about atmospheric circulation changes during dry and wet epochs are possible. Here, a fully-coupled global climate simulation (AOGCM) covering the past 6000 years is analysed regarding ISM variability. Several dry and wet epochs are found, the most striking around 2ka BP (dry) and 1.7ka BP (wet). As only orbital parameters change during integration, we expect these "shorter-term" changes to be associated with changes in oceanic conditions. During 1.7ka BP the sea surface temperatures (SST) over the Northern Arabian Sea (NARAB) are significantly warmer compared to 2ka BP, whereas cooler conditions are found over the western Pacific Ocean. Additionally, significant differences are found over large parts of the North Atlantic. To explain in how far these different ocean basins are responsible for anomalous conditions during 1.7ka BP, several sensitivity experiments with changed SST/SIC conditions are carried out. It is found that neither the SST's in the Pacific nor in the Indian Ocean are able to reproduce the anomalous rainfall and atmospheric circulation patterns during 1.7ka on its own. Instead, anomalous dry conditions during 2ka BP and wet conditions during 1.7ka BP are associated with a shift of the Indo-Pacific-Warm-Pool (IPWP) and simultaneous anomalous sea-surface temperatures over the NARAB region. Eventually, it is tested in how far this hypothesis holds true for other dry and wet events in the AOGCM data during the whole 6000 years. In general, a shift of the IPWP without anomalous SST conditions over the NARAB region (and vice versa) is not sufficient to cause long-lasting rainfall variations over India on a centennial time-scale.

Microwave Heating-Assisted Catalytic Dry Reforming of Methane to Syngas.

PubMed

Hamzehlouia, Sepehr; Jaffer, Shaffiq A; Chaouki, Jamal

2018-06-12

Natural gas is a robust and environmentally friendlier alternative to oil resources for energy and chemicals production. However, gas is distributed globally within shales and hydrates, which are generally remote and difficult reserves to produce. The accessibility, transportation, and distribution, therefore, bring major capital costs. With today's low and foreseen low price of natural gas, conversion of natural gas to higher value-added chemicals is highly sought by industry. Dry reforming of methane (DRM) is a technology pathway to convert two critical greenhouse gas components, CH 4 and CO 2 , to syngas, a commodity chemical feedstock. To date, the challenges of carbon deposition on the catalyst and evolution of secondary gas-phase products have prevented the commercial application of the DRM process. The recent exponential growth of renewable electricity resources, wind and solar power, provides a major opportunity to activate reactions by harnessing low-cost carbon-free energy via microwave-heating. This study takes advantage of differences in dielectric properties of materials to enable selective heating by microwave to create a large thermal gradient between a catalyst surface and the gas phase. Consequently, the reaction kinetics at the higher temperature catalyst surface are promoted while the reactions of lower temperature secondary gas-phase are reduced.

Water-hyacinth production primary and advanced treatment of wastewater. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schwegler, B.R. Jr.

1983-01-01

A prototype water hyacinth wastewater treatment system has been in operation for two years at Walt Disney World, near Orlando, Florida. Typically, the hyacinth system removes 80-90% total suspended solids and B.O.D. from the influent stream. Major impacts on water quality exiting the system are: seasonal variations in solar radiation, air and water temperature; operational problems, particularly harvesting equipment breakdown, and retention time in the ponds. Phosphorus and nitrogen removal show a strong seasonal dependence, with removal rates varying from 0.08 to 1.11 g/m/sup 2//day for N and from 0.05 to 0.29 g/m/sup 2//day for P. Nitrogen removal rates showmore » a strong dependence on retention times, with a retention time of 5 days appearing to be a critical limit for the establishment of an active population of denitrifying bacteria. Hyacinth biomass productivity of the system was approximately 66.7 dry metric tons per hectare year (30 dry tons/acre year) during the second year of operation. An Experimental Test Unit (ETU) for anaerobic digestion of hyacinths to methane will be installed by late 1983.« less

Nutrient and phytochemical composition of two varieties of Monkey kola (Cola parchycarpa and Cola lepidota): An underutilised fruit.

PubMed

Ene-Obong, Henrietta N; Okudu, Helen O; Asumugha, Ukamaka V

2016-02-15

The nutrient and phytochemical composition of two varieties of Monkey kola: Cola parchycarpa and Cola lepidota were determined. The pulps were extracted, grated and dried using solar dryer. Dried pulps were milled into flour with attrition milling machine (0.5mm sieve size). The nutrient compositions were determined using standard AOAC methods. Gravimetric and spectrophotometric methods were used for phytochemical determinations. There were significant (p<0.05) differences in the proximate and some mineral and vitamin composition of the two varieties. Most abundant minerals were calcium (195-199mg for C. parchycarpa), potassium (204-209mg/100g for C. lepidota) and β-carotene (2755-5028μg/100g for C. parchycarpa). Calcium:phosphorus and sodium:potassium ratios were adequate (>1.0 and ⩽0.06, respectively). Monkey kola had substantial amounts of iron, zinc, and copper; the B-vitamins and vitamin C. The phytochemical contents were quiet high, the most abundant being flavonoids (415-494mg/100g). Monkey kola is a fruit that should be fully exploited for its potential health benefits. Copyright © 2014 Elsevier Ltd. All rights reserved.

The use of time and space by the Panamanian tamarin, Saguinus oedipus.

PubMed

Dawson, G A

1979-01-01

Tamarin activity patterns and habitat utilization strategies in the Tropical Dry Forest of the Panama Canal Zone were monitored quantitatively using radio-location telemetry. The daily tamarin activity pattern differed from that of other Neotropical primates in that early morning and late afternoon activity normally did not occur. Total daily activity time averaged 676 +/- 62 min. Sleeping trees, and behaviors associated with their use, were documented. Daily path length averaged 2,061 +/- 402 m. Mean travel distance was 468 +/- 66 m. Approximately one-third of the home range was utilized on a given day. Wet season home ranges for two social groups were 26 and 32 ha in area. Areas of low brush, forest edge, and vine-entangled second growth were heavily used by foraging tamarins. Large shade trees, particularly evergreens, were important as refuges from solar radiation. Open-canopy forest types and areas of grass were avoided. Social groups on resource-stable lowland sites defended territories; those on unstable upland sites used a system of time-space segregation. Upland groups became seminomadic during the dry season. Suitability of home range site may affect social group stability, natality, and infant survivorship.

Seasonal variations of Saanen goat milk composition and the impact of climatic conditions.

PubMed

Kljajevic, Nemanja V; Tomasevic, Igor B; Miloradovic, Zorana N; Nedeljkovic, Aleksandar; Miocinovic, Jelena B; Jovanovic, Snezana T

2018-01-01

The aim of this research was to investigate the effect of climatic conditions and their impact on seasonal variations of physico-chemical characteristics of Saanen goat milk produced over a period of 4 years. Lactation period (early, mid and late) and year were considered as factors that influence physico-chemical composition of milk. Pearson's coefficient of correlation was calculated between the physico-chemical characteristics of milk (fat, proteins, lactose, non-fat dry matter, density, freezing point, pH, titrable acidity) and climatic condition parameters (air temperature, temperature humidity index-THI, solar radiation duration, relative humidity). Results showed that all physico-chemical characteristics of Saanen goat milk varied significantly throughout the lactation period and years. The decrease of fat, protein, non-fat dry matter and lactose content in goat milk during the mid-lactation period was more pronounced than was previously reported in the literature. The highest values for these characteristics were recorded in the late lactation period. Observed variations were explained by negative correlation between THI and the physico-chemical characteristics of Saanen goat milk. This indicated that Saanen goats were very prone to heat stress, which implied the decrease of physico-chemical characteristics during hot summers.

Caribbean-wide, long-term study of seagrass beds reveals local variations, shifts in community structure and occasional collapse.

PubMed

van Tussenbroek, Brigitta I; Cortés, Jorge; Collin, Rachel; Fonseca, Ana C; Gayle, Peter M H; Guzmán, Hector M; Jácome, Gabriel E; Juman, Rahanna; Koltes, Karen H; Oxenford, Hazel A; Rodríguez-Ramirez, Alberto; Samper-Villarreal, Jimena; Smith, Struan R; Tschirky, John J; Weil, Ernesto

2014-01-01

The CARICOMP monitoring network gathered standardized data from 52 seagrass sampling stations at 22 sites (mostly Thalassia testudinum-dominated beds in reef systems) across the Wider Caribbean twice a year over the period 1993 to 2007 (and in some cases up to 2012). Wide variations in community total biomass (285 to >2000 g dry m(-2)) and annual foliar productivity of the dominant seagrass T. testudinum (<200 and >2000 g dry m(-2)) were found among sites. Solar-cycle related intra-annual variations in T. testudinum leaf productivity were detected at latitudes > 16°N. Hurricanes had little to no long-term effects on these well-developed seagrass communities, except for 1 station, where the vegetation was lost by burial below ∼1 m sand. At two sites (5 stations), the seagrass beds collapsed due to excessive grazing by turtles or sea-urchins (the latter in combination with human impact and storms). The low-cost methods of this regional-scale monitoring program were sufficient to detect long-term shifts in the communities, and fifteen (43%) out of 35 long-term monitoring stations (at 17 sites) showed trends in seagrass communities consistent with expected changes under environmental deterioration.

Space Science Reference Guide, 2nd Edition

NASA Technical Reports Server (NTRS)

Dotson, Renee (Editor)

2003-01-01

This Edition contains the following reports: GRACE: Gravity Recovery and Climate Experiment; Impact Craters in the Solar System; 1997 Apparition of Comet Hale-Bopp Historical Comet Observations; Baby Stars in Orion Solve Solar System Mystery; The Center of the Galaxy; The First Rock in the Solar System; Fun Times with Cosmic Rays; The Gamma-Ray Burst Next Door; The Genesis Mission: An Overview; The Genesis Solar Wind Sample Return Mission; How to Build a Supermassive Black Hole; Journey to the Center of a Neutron Star; Kepler's Laws of Planetary Motion; The Kuiper Belt and Oort Cloud ; Mapping the Baby Universe; More Hidden Black Hole Dangers; A Polarized Universe; Presolar Grains of Star Dust: Astronomy Studied with Microscopes; Ring Around the Black Hole; Searching Antarctic Ice for Meteorites; The Sun; Astrobiology: The Search for Life in the Universe; Europa and Titan: Oceans in the Outer Solar System?; Rules for Identifying Ancient Life; Inspire ; Remote Sensing; What is the Electromagnetic Spectrum? What is Infrared? How was the Infrared Discovered?; Brief History of Gyroscopes ; Genesis Discovery Mission: Science Canister Processing at JSC; Genesis Solar-Wind Sample Return Mission: The Materials ; ICESat: Ice, Cloud, and Land Elevation Satellite ICESat: Ice, Cloud, and Land; Elevation Satellite ICESat: Ice, Cloud, and Land Elevation Satellite ICESat: Ice, Cloud, and Land Elevation Satellite ICESat: Ice, Cloud, and Land Elevation Satellite Measuring Temperature Reading; The Optical Telescope ; Space Instruments General Considerations; Damage by Impact: The Case at Meteor Crater, Arizona; Mercury Unveiled; New Data, New Ideas, and Lively Debate about Mercury; Origin of the Earth and Moon; Space Weather: The Invisible Foe; Uranus, Neptune, and the Mountains of the Moon; Dirty Ice on Mars; For a Cup of Water on Mars; Life on Mars?; The Martian Interior; Meteorites from Mars, Rocks from Canada; Organic Compounds in Martian Meteorites May be Terrestrial Contaminants; Bands on Europa;Big Mountain, Big Landslide on Jupiter's Moon, Io; Cratering of the Moon; Europa's Salty Surface; The Europa Scene in the Voyager-Galileo Era; Explosive Volcanic Eruptions on the Moon; Ice on the Bone Dry Moon; Jupiter's Hot, Mushy Moon; The Moon Beyond 2002 ; Phases of the Moon; The Ph-D Project: Manned Expedition to the Moons of Mars; and Possible Life in a Europan Ocean.

Isca, v1.0: a framework for the global modelling of the atmospheres of Earth and other planets at varying levels of complexity

NASA Astrophysics Data System (ADS)

Vallis, Geoffrey K.; Colyer, Greg; Geen, Ruth; Gerber, Edwin; Jucker, Martin; Maher, Penelope; Paterson, Alexander; Pietschnig, Marianne; Penn, James; Thomson, Stephen I.

2018-03-01

Isca is a framework for the idealized modelling of the global circulation of planetary atmospheres at varying levels of complexity and realism. The framework is an outgrowth of models from the Geophysical Fluid Dynamics Laboratory in Princeton, USA, designed for Earth's atmosphere, but it may readily be extended into other planetary regimes. Various forcing and radiation options are available, from dry, time invariant, Newtonian thermal relaxation to moist dynamics with radiative transfer. Options are available in the dry thermal relaxation scheme to account for the effects of obliquity and eccentricity (and so seasonality), different atmospheric optical depths and a surface mixed layer. An idealized grey radiation scheme, a two-band scheme, and a multiband scheme are also available, all with simple moist effects and astronomically based solar forcing. At the complex end of the spectrum the framework provides a direct connection to comprehensive atmospheric general circulation models. For Earth modelling, options include an aquaplanet and configurable continental outlines and topography. Continents may be defined by changing albedo, heat capacity, and evaporative parameters and/or by using a simple bucket hydrology model. Oceanic Q fluxes may be added to reproduce specified sea surface temperatures, with arbitrary continental distributions. Planetary atmospheres may be configured by changing planetary size and mass, solar forcing, atmospheric mass, radiation, and other parameters. Examples are given of various Earth configurations as well as a giant planet simulation, a slowly rotating terrestrial planet simulation, and tidally locked and other orbitally resonant exoplanet simulations. The underlying model is written in Fortran and may largely be configured with Python scripts. Python scripts are also used to run the model on different architectures, to archive the output, and for diagnostics, graphics, and post-processing. All of these features are publicly available in a Git-based repository.

Seasonality of Fire Weather Strongly Influences Fire Regimes in South Florida Savanna-Grassland Landscapes

PubMed Central

Platt, William J.; Orzell, Steve L.; Slocum, Matthew G.

2015-01-01

Fire seasonality, an important characteristic of fire regimes, commonly is delineated using seasons based on single weather variables (rainfall or temperature). We used nonparametric cluster analyses of a 17-year (1993–2009) data set of weather variables that influence likelihoods and spread of fires (relative humidity, air temperature, solar radiation, wind speed, soil moisture) to explore seasonality of fire in pine savanna-grassland landscapes at the Avon Park Air Force Range in southern Florida. A four-variable, three-season model explained more variation within fire weather variables than models with more seasons. The three-season model also delineated intra-annual timing of fire more accurately than a conventional rainfall-based two-season model. Two seasons coincided roughly with dry and wet seasons based on rainfall. The third season, which we labeled the fire season, occurred between dry and wet seasons and was characterized by fire-promoting conditions present annually: drought, intense solar radiation, low humidity, and warm air temperatures. Fine fuels consisting of variable combinations of pyrogenic pine needles, abundant C4 grasses, and flammable shrubs, coupled with low soil moisture, and lightning ignitions early in the fire season facilitate natural landscape-scale wildfires that burn uplands and across wetlands. We related our three season model to fires with different ignition sources (lightning, military missions, and prescribed fires) over a 13-year period with fire records (1997–2009). Largest wildfires originate from lightning and military ignitions that occur within the early fire season substantially prior to the peak of lightning strikes in the wet season. Prescribed ignitions, in contrast, largely occur outside the fire season. Our delineation of a pronounced fire season provides insight into the extent to which different human-derived fire regimes mimic lightning fire regimes. Delineation of a fire season associated with timing of natural lightning ignitions should be useful as a basis for ecological fire management of humid savanna-grassland landscapes worldwide. PMID:25574667

Determining the K coefficient to leaf area index estimations in a tropical dry forest

NASA Astrophysics Data System (ADS)

Magalhães, Sarah Freitas; Calvo-Rodriguez, Sofia; do Espírito Santo, Mário Marcos; Sánchez Azofeifa, Gerardo Arturo

2018-03-01

Vegetation indices are useful tools to remotely estimate several important parameters related to ecosystem functioning. However, improving and validating estimations for a wide range of vegetation types are necessary. In this study, we provide a methodology for the estimation of the leaf area index (LAI) in a tropical dry forest (TDF) using the light diffusion through the canopy as a function of the successional stage. For this purpose, we estimated the K coefficient, a parameter that relates the normalized difference vegetation index (NDVI) to LAI, based on photosynthetically active radiation (PAR) and solar radiation. The study was conducted in the Mata Seca State Park, in southeastern Brazil, from 2012 to 2013. We defined four successional stages (very early, early, intermediate, and late) and established one optical phenology tower at one plot of 20 × 20 m per stage. Towers measured the incoming and reflected solar radiation and PAR for NDVI calculation. For each plot, we established 24 points for LAI sampling through hemispherical photographs. Because leaf cover is highly seasonal in TDFs, we determined ΔK (leaf growth phase) and K max (leaf maturity phase). We detected a strong correlation between NDVI and LAI, which is necessary for a reliable determination of the K coefficient. Both NDVI and LAI varied significantly between successional stages, indicating sensitivity to structural changes in forest regeneration. Furthermore, the K values differed between successional stages and correlated significantly with other environmental variables such as air temperature and humidity, fraction of absorbed PAR, and soil moisture. Thus, we established a model based on spectral properties of the vegetation coupled with biophysical characteristics in a TDF that makes possible to estimate LAI from NDVI values. The application of the K coefficient can improve remote estimations of forest primary productivity and gases and energy exchanges between vegetation and atmosphere. This model can be applied to distinguish different successional stages of TDFs, supporting environmental monitoring and conservation policies towards this biome.

Seasonality of fire weather strongly influences fire regimes in South Florida savanna-grassland landscapes.

PubMed

Platt, William J; Orzell, Steve L; Slocum, Matthew G

2015-01-01

Fire seasonality, an important characteristic of fire regimes, commonly is delineated using seasons based on single weather variables (rainfall or temperature). We used nonparametric cluster analyses of a 17-year (1993-2009) data set of weather variables that influence likelihoods and spread of fires (relative humidity, air temperature, solar radiation, wind speed, soil moisture) to explore seasonality of fire in pine savanna-grassland landscapes at the Avon Park Air Force Range in southern Florida. A four-variable, three-season model explained more variation within fire weather variables than models with more seasons. The three-season model also delineated intra-annual timing of fire more accurately than a conventional rainfall-based two-season model. Two seasons coincided roughly with dry and wet seasons based on rainfall. The third season, which we labeled the fire season, occurred between dry and wet seasons and was characterized by fire-promoting conditions present annually: drought, intense solar radiation, low humidity, and warm air temperatures. Fine fuels consisting of variable combinations of pyrogenic pine needles, abundant C4 grasses, and flammable shrubs, coupled with low soil moisture, and lightning ignitions early in the fire season facilitate natural landscape-scale wildfires that burn uplands and across wetlands. We related our three season model to fires with different ignition sources (lightning, military missions, and prescribed fires) over a 13-year period with fire records (1997-2009). Largest wildfires originate from lightning and military ignitions that occur within the early fire season substantially prior to the peak of lightning strikes in the wet season. Prescribed ignitions, in contrast, largely occur outside the fire season. Our delineation of a pronounced fire season provides insight into the extent to which different human-derived fire regimes mimic lightning fire regimes. Delineation of a fire season associated with timing of natural lightning ignitions should be useful as a basis for ecological fire management of humid savanna-grassland landscapes worldwide.

Edge effects on foliar stable isotope values in a Madagascan tropical dry forest.

PubMed

Crowley, Brooke E; McGoogan, Keriann C; Lehman, Shawn M

2012-01-01

Edge effects represent an inevitable and important consequence of habitat loss and fragmentation. These effects include changes in microclimate, solar radiation, or temperature. Such abiotic effects can, in turn, impact biotic factors. They can have a substantial impact on species, communities, and ecosystems. Here we examine clinal variations in stable carbon and nitrogen isotope values for trees along an edge-interior gradient in the dry deciduous forest at Ankarafantsika National Park. We predicted that soil respiration and differences in solar irradiance would result in stratified δ¹³C values where leaves collected close to the forest floor would have lower δ¹³C values than those growing higher up in the canopy. We also anticipated that plants growing at the savannah-forest boundary would have higher δ¹³C and δ¹⁵N values than plants growing in the forest interior. As expected, we detected a small but significant canopy effect. Leaves growing below 2 m from the forest floor exhibit δ¹³C values that are, on average, 1.1‰ lower than those growing above this threshold. We did not, however, find any relationship between foliar δ¹³C and distance from the edge. Unpredictably, we detected a striking positive relationship between foliar δ¹⁵N values and increasing distance into the forest interior. Variability in physiology among species, anthropogenic influence, organic input, and rooting depth cannot adequately explain this trend. Instead, this unexpected relationship most likely reflects decreasing nutrient or water availability, or a shift in N-sources with increasing distance from the savannah. Unlike most forest communities, the trees at Ampijoroa are growing in nutrient-limited sands. In addition to being nutrient poor, these well-drained soils likely decrease the amount of soil water available to forest vegetation. Continued research on plant responses to edge effects will improve our understanding of the conservation biology of forest ecosystems in Madagascar.

Edge Effects on Foliar Stable Isotope Values in a Madagascan Tropical Dry Forest

PubMed Central

Crowley, Brooke E.; McGoogan, Keriann C.; Lehman, Shawn M.

2012-01-01

Edge effects represent an inevitable and important consequence of habitat loss and fragmentation. These effects include changes in microclimate, solar radiation, or temperature. Such abiotic effects can, in turn, impact biotic factors. They can have a substantial impact on species, communities, and ecosystems. Here we examine clinal variations in stable carbon and nitrogen isotope values for trees along an edge-interior gradient in the dry deciduous forest at Ankarafantsika National Park. We predicted that soil respiration and differences in solar irradiance would result in stratified δ13C values where leaves collected close to the forest floor would have lower δ13C values than those growing higher up in the canopy. We also anticipated that plants growing at the savannah-forest boundary would have higher δ13C and δ15N values than plants growing in the forest interior. As expected, we detected a small but significant canopy effect. Leaves growing below 2 m from the forest floor exhibit δ13C values that are, on average, 1.1‰ lower than those growing above this threshold. We did not, however, find any relationship between foliar δ13C and distance from the edge. Unpredictably, we detected a striking positive relationship between foliar δ15N values and increasing distance into the forest interior. Variability in physiology among species, anthropogenic influence, organic input, and rooting depth cannot adequately explain this trend. Instead, this unexpected relationship most likely reflects decreasing nutrient or water availability, or a shift in N-sources with increasing distance from the savannah. Unlike most forest communities, the trees at Ampijoroa are growing in nutrient-limited sands. In addition to being nutrient poor, these well-drained soils likely decrease the amount of soil water available to forest vegetation. Continued research on plant responses to edge effects will improve our understanding of the conservation biology of forest ecosystems in Madagascar. PMID:22973460

A Thruster Sub-System Module (TSSM) for solar electric propulsion

NASA Technical Reports Server (NTRS)

Sharp, G. R.

1975-01-01

Solar Electric Propulsion (SEP) is currently being studied for possible use in a number of near-earth and planetary missions. Thruster systems for these missions could be integrated directly into a spacecraft or modularized into a Thruster Sub-System Module (TSSM). A TSSM for electric propulsion missions would consist of a 30-cm ion thruster, thruster gimbal system, propellant storage and feed system, associated Power Processing Unit (PPU), thermal control system and complete supporting structure. The TSSM would be wholly self-contained and be essentially a plug-in or strap-on electric stage with simple mechanical, thermal, electrical and propellant interfaces. The TSSM described in this report is designed for a broad range of missions requiring from two to ten TSSM's mounted in a 2 by x configuration. The thermal control system is designed to accommodate waste heat from the power processor based on realistic efficiencies when the TSSM is operating from 0.7 to 3.5 AU's. The modules are 0.61 M (2 ft) wide by 2.29 M (7.5 ft) long and have a dry weight including propellant tank of 54.4 kg (120 lb). The propellant tank will hold 145.1 kg (320 lb) of mercury.

Increased accumulation of polyhydroxybutyrate in divergent cyanobacteria under nutrient-deprived photoautotrophy: An efficient conversion of solar energy and carbon dioxide to polyhydroxybutyrate by Calothrix scytonemicola TISTR 8095.

PubMed

Kaewbai-Ngam, Auratai; Incharoensakdi, Aran; Monshupanee, Tanakarn

2016-07-01

The cellular PHB content was determined in 137 strains of cyanobacteria representing 88 species in 26 genera under six photoautotrophic nutrient conditions. One hundred and thirty-four strains were PHB producers. The PHB contents of these 134 strains were subtle under normal growth condition, but were significantly increased in 63 strains under nitrogen deprivation (-N), a higher frequency than with phosphate and/or potassium and all-nutrient deprivation. A high PHB accumulation was not associated with any particular evolutionary groups, but was strain specific. The filamentous Calothrix scytonemicola TISTR 8095 produced 356.5±63.4mg/L PHB under -N from a biomass of 1396.6±66.1mg/L, giving a PHB content of 25.4±3.5% (w/w dry weight). This PHB productivity is equivalent to the CO2 consumption of 729.2±129.8mg/L. The maximum energy conversion from solar energy to PHB obtained by C. scytonemicola TISTR 8095 was 1.42±0.30%. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Organism/Organic Exposure to Orbital Stresses (O/OREOS) satellite: radiation exposure in low-earth orbit and supporting laboratory studies of iron tetraphenylporphyrin chloride.

PubMed

Cook, Amanda M; Mattioda, Andrew L; Ricco, Antonio J; Quinn, Richard C; Elsaesser, Andreas; Ehrenfreund, Pascale; Ricca, Alessandra; Jones, Nykola C; Hoffmann, Søren V

2014-02-01

We report results from the exposure of the metalloporphyrin iron tetraphenylporphyrin chloride (FeTPPCl) to the outer space environment, measured in situ aboard the Organism/Organic Exposure to Orbital Stresses nanosatellite. FeTPPCl was exposed for a period of 17 months (3700 h of direct solar exposure), which included broad-spectrum solar radiation (∼122 nm to the near infrared). Motivated by the potential role of metalloporphyrins as molecular biomarkers, the exposure of thin-film samples of FeTPPCl to the space environment in low-Earth orbit was monitored in situ via ultraviolet/visible spectroscopy and reported telemetrically. The space data were complemented by laboratory exposure experiments that used a high-fidelity solar simulator covering the spectral range of the spaceflight measurements. We found that thin-film samples of FeTPPCl that were in contact with a humid headspace gas (0.8-2.3% relative humidity) were particularly susceptible to destruction upon irradiation, degrading up to 10 times faster than identical thin films in contact with dry headspace gases; this degradation may also be related to the presence of oxides of nitrogen in those cells. In the companion terrestrial experiments, simulated solar exposure of FeTPPCl films in contact with either Ar or CO2:O2:Ar (10:0.01:1000) headspace gas resulted in growth of a band in the films' infrared spectra at 1961 cm(-1). We concluded that the most likely carriers of this band are allene (C3H4) and chloropropadiene (C3H3Cl), putative molecular fragments of the destruction of the porphyrin ring. The thin films studied in space and in solar simulator-based experiments show qualitatively similar spectral evolution as a function of contacting gaseous species but display significant differences in the time dependence of those changes. The relevance of our findings to planetary science, biomarker research, and the photostability of organic materials in astrobiologically relevant environments is discussed.

IAF 15 Draft Paper

NASA Technical Reports Server (NTRS)

Menkin, Evgeny; Juillerat, Robert

2015-01-01

With the International Space Station Program transition from assembly to utilization, focus has been placed on the optimization of essential resources. This includes resources both resupplied from the ground and also resources produced by the ISS. In an effort to improve the use of two of these, the ISS Engineering teams, led by the ISS Program Systems Engineering and Integration Office, undertook an effort to modify the techniques use to perform several key on-orbit events. The primary purposes of this endeavor was to make the ISS more efficient in the use of the Russian-supplied fuel for the propulsive attitude control system and also to minimize the impacts to available ISS power due to the positioning of the ISS solar arrays. Because the ISS solar arrays are sensitive to several factors that are present when propulsive attitude control is used, they must be operated in a manner to protect them from damage. This results in periods of time where the arrays must be positioned, rather than autonomously tracking the sun, resulting in negative impacts to power generated by the solar arrays and consumed by both the ISS core systems and payload customers. A reduction in the number and extent of the events each year that require the ISS to use propulsive attitude control simultaneously accomplishes both these goals. Each instance where the ISS solar arrays normal sun tracking mode must be interrupted represent a need for some level of powerdown of equipment. As the magnitude of payload power requirements increases, and the efficiency of the ISS solar arrays decreases, these powerdowns caused by array positioning, will likely become more significant and could begin to negatively impact the payload operations. Through efforts such as this, the total number of events each year that require positioning of the arrays to unfavorable positions for power generation, in order to protect them against other constraints, are reduced. Optimization of propulsive events and transitioning some of them to non-propulsive CMG control significantly reduces propellant usage on the ISS leading to the reduction of the propellant delivery requirement. This results in move available upmass that can be used for delivering critical dry cargo, additional water, air, crew supplies and science experiments.

Combinatorial screening of halide perovskite thin films and solar cells by mask-defined IR laser molecular beam epitaxy

PubMed Central

Kawashima, Kazuhiro; Okamoto, Yuji; Annayev, Orazmuhammet; Toyokura, Nobuo; Takahashi, Ryota; Lippmaa, Mikk; Itaka, Kenji; Suzuki, Yoshikazu; Matsuki, Nobuyuki; Koinuma, Hideomi

2017-01-01

Abstract As an extension of combinatorial molecular layer epitaxy via ablation of perovskite oxides by a pulsed excimer laser, we have developed a laser molecular beam epitaxy (MBE) system for parallel integration of nano-scaled thin films of organic–inorganic hybrid materials. A pulsed infrared (IR) semiconductor laser was adopted for thermal evaporation of organic halide (A-site: CH3NH3I) and inorganic halide (B-site: PbI2) powder targets to deposit repeated A/B bilayer films where the thickness of each layer was controlled on molecular layer scale by programming the evaporation IR laser pulse number, length, or power. The layer thickness was monitored with an in situ quartz crystal microbalance and calibrated against ex situ stylus profilometer measurements. A computer-controlled movable mask system enabled the deposition of combinatorial thin film libraries, where each library contains a vertically homogeneous film with spatially programmable A- and B-layer thicknesses. On the composition gradient film, a hole transport Spiro-OMeTAD layer was spin-coated and dried followed by the vacuum evaporation of Ag electrodes to form the solar cell. The preliminary cell performance was evaluated by measuring I-V characteristics at seven different positions on the 12.5 mm × 12.5 mm combinatorial library sample with seven 2 mm × 4 mm slits under a solar simulator irradiation. The combinatorial solar cell library clearly demonstrated that the energy conversion efficiency sharply changes from nearly zero to 10.2% as a function of the illumination area in the library. The exploration of deposition parameters for obtaining optimum performance could thus be greatly accelerated. Since the thickness ratio of PbI2 and CH3NH3I can be freely chosen along the shadow mask movement, these experiments show the potential of this system for high-throughput screening of optimum chemical composition in the binary film library and application to halide perovskite solar cell. PMID:28567176

Exploring impacts of El Niño Southern Oscillation on Meteorological Forcing within the Glaciated Llanganuco Valley, Peru

NASA Astrophysics Data System (ADS)

Covert, J. M.; Hellstrom, R. A.

2015-12-01

El Niño Southern Oscillation (ENSO) is known to be the primary modulator of inter-annual weather patterns in the Andes, but its impact in the Cordillera Blanca (White Range) is not fully understood. In 2004 an autonomous sensor network (ASN) was installed in the Llanganuco Valley in the Cordillera Blanca, Peru consisting of two automatic weather stations (AWS) located at the base and upper ridge of the valley connected by four air temperature/humidity micro-loggers at equal elevation intervals. The ASN permits high resolution evaluations of the micro-scale meteorology within the valley. Twenty-four hour composites and monthly averages of wind, solar insolation, air temperature profiles, and precipitation obtained from the ASN were analyzed for the historical wet and dry seasons between the years of 2005 and 2015. The evidence suggests that teleconnections exist between eastern equatorial Pacific Ocean sea surface temperatures and meteorological forcing within the Valley. Comparisons between the two AWS units reveal similar ENSO impacts during the wet season that are not replicated in the dry season. We found that warm and cold ENSO create anomalies that appear unique to this region of the outer Tropics. Warm ENSO phases promote wetter than normal dry seasons and dryer than normal wet seasons and visa versa for cold phases of ENSO. Air temperature is strongly positively correlated to warm ENSO phases during the wet season and depends on elevation during the dry season. Insolation is negatively correlated to warm ENSO phases at higher elevations with weak positive correlation at lower elevations. We attribute observed seasonality, in part, to interactions between channeling of synoptic flow and thermally driven winds. Although the sporadic availability of data prevents definitive conclusions at this time, recent improvements in the ASN infrastructure will facilitate deeper understanding of ENSO impacts on meteorological forcing within pro-glacial valleys of the Cordillera Blanca.

Growth and reproduction respond differently to climate in three Neotropical tree species.

PubMed

Alfaro-Sánchez, Raquel; Muller-Landau, Helene C; Wright, S Joseph; Camarero, J Julio

2017-06-01

The response of tropical forests to anthropogenic climate change is critically important to future global carbon budgets, yet remains highly uncertain. Here, we investigate how precipitation, temperature, solar radiation and dry- and wet-season lengths are related to annual tree growth, flower production, and fruit production in three moist tropical forest tree species using long-term datasets from tree rings and litter traps in central Panama. We also evaluated how growth, flower, and fruit production were interrelated. We found that growth was positively correlated with wet-season precipitation in all three species: Jacaranda copaia (r = 0.63), Tetragastris panamensis (r = 0.39) and Trichilia tuberculata (r = 0.39). Flowering and fruiting in Jacaranda were negatively related to current-year dry-season rainfall and positively related to prior-year dry-season rainfall. Flowering in Tetragastris was negatively related to current-year annual mean temperature while Trichilia showed no significant relationships of reproduction with climate. Growth was significantly related to reproduction only in Tetragastris, where it was positively related to previous year fruiting. Our results suggest that tree growth in moist tropical forest tree species is generally reduced by drought events such as those associated with strong El Niño events. In contrast, interannual variation in reproduction is not generally associated with growth and has distinct and species-specific climate responses, with positive effects of El Niño events in some species. Understanding these contrasting climate effects on tree growth and reproduction is critical to predicting changes in tropical forest dynamics and species composition under climate change.

Potential for real-time understanding of coupled hydrologic and biogeochemical processes in stream ecosystems: Future integration of telemetered data with process models for glacial meltwater streams

NASA Astrophysics Data System (ADS)

McKnight, Diane M.; Cozzetto, Karen; Cullis, James D. S.; Gooseff, Michael N.; Jaros, Christopher; Koch, Joshua C.; Lyons, W. Berry; Neupauer, Roseanna; Wlostowski, Adam

2015-08-01

While continuous monitoring of streamflow and temperature has been common for some time, there is great potential to expand continuous monitoring to include water quality parameters such as nutrients, turbidity, oxygen, and dissolved organic material. In many systems, distinguishing between watershed and stream ecosystem controls can be challenging. The usefulness of such monitoring can be enhanced by the application of quantitative models to interpret observed patterns in real time. Examples are discussed primarily from the glacial meltwater streams of the McMurdo Dry Valleys, Antarctica. Although the Dry Valley landscape is barren of plants, many streams harbor thriving cyanobacterial mats. Whereas a daily cycle of streamflow is controlled by the surface energy balance on the glaciers and the temporal pattern of solar exposure, the daily signal for biogeochemical processes controlling water quality is generated along the stream. These features result in an excellent outdoor laboratory for investigating fundamental ecosystem process and the development and validation of process-based models. As part of the McMurdo Dry Valleys Long-Term Ecological Research project, we have conducted field experiments and developed coupled biogeochemical transport models for the role of hyporheic exchange in controlling weathering reactions, microbial nitrogen cycling, and stream temperature regulation. We have adapted modeling approaches from sediment transport to understand mobilization of stream biomass with increasing flows. These models help to elucidate the role of in-stream processes in systems where watershed processes also contribute to observed patterns, and may serve as a test case for applying real-time stream ecosystem models.

Survival of fecal coliforms in dry-composting toilets.

PubMed

Redlinger, T; Graham, J; Corella-Barud, V; Avitia, R

2001-09-01

The dry-composting toilet, which uses neither water nor sewage infrastructure, is a practical solution in areas with inadequate sewage disposal and where water is limited. These systems are becoming increasingly popular and are promoted to sanitize human excreta and to recycle them into fertilizer for nonedible plants, yet there are few data on the safety of this technology. This study analyzed fecal coliform reduction in approximately 90 prefabricated, dry-composting toilets (Sistema Integral de Reciclamiento de Desechos Orgánicos [SIRDOs]) that were installed on the U.S.-Mexico border in Ciudad Juárez, Chihuahua, Mexico. The purpose of this study was to determine fecal coliform reduction over time and the most probable method of this reduction. Biosolid waste samples were collected and analyzed at approximately 3 and 6 months and were classified based on U.S. Environmental Protection Agency standards. Results showed that class A compost (high grade) was present in only 35.8% of SIRDOs after 6 months. The primary mechanism for fecal coliform reduction was found to be desiccation rather than biodegradation. There was a significant correlation (P = 0.008) between classification rating and percent moisture categories of the biosolid samples: drier samples had a greater proportion of class A samples. Solar exposure was critical for maximal class A biosolid end products (P = 0.001). This study only addressed fecal coliforms as an indicator organism, and further research is necessary to determine the safety of composting toilets with respect to other pathogenic microorganisms, some of which are more resistant to desiccation.

Rainfall and its seasonality over the Amazon in the 21st century as assessed by the coupled models for the IPCC AR4

NASA Astrophysics Data System (ADS)

Li, Wenhong; Fu, Rong; Dickinson, Robert E.

2006-01-01

The global climate models for the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC AR4) predict very different changes of rainfall over the Amazon under the SRES A1B scenario for global climate change. Five of the eleven models predict an increase of annual rainfall, three models predict a decrease of rainfall, and the other three models predict no significant changes in the Amazon rainfall. We have further examined two models. The UKMO-HadCM3 model predicts an El Niño-like sea surface temperature (SST) change and warming in the northern tropical Atlantic which appear to enhance atmospheric subsidence and consequently reduce clouds over the Amazon. The resultant increase of surface solar absorption causes a stronger surface sensible heat flux and thus reduces relative humidity of the surface air. These changes decrease the rate and length of wet season rainfall and surface latent heat flux. This decreased wet season rainfall leads to drier soil during the subsequent dry season, which in turn can delay the transition from the dry to wet season. GISS-ER predicts a weaker SST warming in the western Pacific and the southern tropical Atlantic which increases moisture transport and hence rainfall in the Amazon. In the southern Amazon and Nordeste where the strongest rainfall increase occurs, the resultant higher soil moisture supports a higher surface latent heat flux during the dry and transition season and leads to an earlier wet season onset.

Formation of highly porous aerosol particles by atmospheric freeze-drying in ice clouds

PubMed Central

Adler, Gabriela; Koop, Thomas; Haspel, Carynelisa; Taraniuk, Ilya; Moise, Tamar; Koren, Ilan; Heiblum, Reuven H.; Rudich, Yinon

2013-01-01

The cycling of atmospheric aerosols through clouds can change their chemical and physical properties and thus modify how aerosols affect cloud microphysics and, subsequently, precipitation and climate. Current knowledge about aerosol processing by clouds is rather limited to chemical reactions within water droplets in warm low-altitude clouds. However, in cold high-altitude cirrus clouds and anvils of high convective clouds in the tropics and midlatitudes, humidified aerosols freeze to form ice, which upon exposure to subsaturation conditions with respect to ice can sublimate, leaving behind residual modified aerosols. This freeze-drying process can occur in various types of clouds. Here we simulate an atmospheric freeze-drying cycle of aerosols in laboratory experiments using proxies for atmospheric aerosols. We find that aerosols that contain organic material that undergo such a process can form highly porous aerosol particles with a larger diameter and a lower density than the initial homogeneous aerosol. We attribute this morphology change to phase separation upon freezing followed by a glass transition of the organic material that can preserve a porous structure after ice sublimation. A porous structure may explain the previously observed enhancement in ice nucleation efficiency of glassy organic particles. We find that highly porous aerosol particles scatter solar light less efficiently than nonporous aerosol particles. Using a combination of satellite and radiosonde data, we show that highly porous aerosol formation can readily occur in highly convective clouds, which are widespread in the tropics and midlatitudes. These observations may have implications for subsequent cloud formation cycles and aerosol albedo near cloud edges. PMID:24297908

Formation of highly porous aerosol particles by atmospheric freeze-drying in ice clouds.

PubMed

Adler, Gabriela; Koop, Thomas; Haspel, Carynelisa; Taraniuk, Ilya; Moise, Tamar; Koren, Ilan; Heiblum, Reuven H; Rudich, Yinon

2013-12-17

The cycling of atmospheric aerosols through clouds can change their chemical and physical properties and thus modify how aerosols affect cloud microphysics and, subsequently, precipitation and climate. Current knowledge about aerosol processing by clouds is rather limited to chemical reactions within water droplets in warm low-altitude clouds. However, in cold high-altitude cirrus clouds and anvils of high convective clouds in the tropics and midlatitudes, humidified aerosols freeze to form ice, which upon exposure to subsaturation conditions with respect to ice can sublimate, leaving behind residual modified aerosols. This freeze-drying process can occur in various types of clouds. Here we simulate an atmospheric freeze-drying cycle of aerosols in laboratory experiments using proxies for atmospheric aerosols. We find that aerosols that contain organic material that undergo such a process can form highly porous aerosol particles with a larger diameter and a lower density than the initial homogeneous aerosol. We attribute this morphology change to phase separation upon freezing followed by a glass transition of the organic material that can preserve a porous structure after ice sublimation. A porous structure may explain the previously observed enhancement in ice nucleation efficiency of glassy organic particles. We find that highly porous aerosol particles scatter solar light less efficiently than nonporous aerosol particles. Using a combination of satellite and radiosonde data, we show that highly porous aerosol formation can readily occur in highly convective clouds, which are widespread in the tropics and midlatitudes. These observations may have implications for subsequent cloud formation cycles and aerosol albedo near cloud edges.

Survival of Fecal Coliforms in Dry-Composting Toilets

PubMed Central

Redlinger, Thomas; Graham, Jay; Corella-Barud, Verónica; Avitia, Raquel

2001-01-01

The dry-composting toilet, which uses neither water nor sewage infrastructure, is a practical solution in areas with inadequate sewage disposal and where water is limited. These systems are becoming increasingly popular and are promoted to sanitize human excreta and to recycle them into fertilizer for nonedible plants, yet there are few data on the safety of this technology. This study analyzed fecal coliform reduction in approximately 90 prefabricated, dry-composting toilets (Sistema Integral de Reciclamiento de Desechos Orgánicos [SIRDOs]) that were installed on the U.S.-Mexico border in Ciudad Juárez, Chihuahua, Mexico. The purpose of this study was to determine fecal coliform reduction over time and the most probable method of this reduction. Biosolid waste samples were collected and analyzed at approximately 3 and 6 months and were classified based on U.S. Environmental Protection Agency standards. Results showed that class A compost (high grade) was present in only 35.8% of SIRDOs after 6 months. The primary mechanism for fecal coliform reduction was found to be desiccation rather than biodegradation. There was a significant correlation (P = 0.008) between classification rating and percent moisture categories of the biosolid samples: drier samples had a greater proportion of class A samples. Solar exposure was critical for maximal class A biosolid end products (P = 0.001). This study only addressed fecal coliforms as an indicator organism, and further research is necessary to determine the safety of composting toilets with respect to other pathogenic microorganisms, some of which are more resistant to desiccation. PMID:11526002

Effects of southeastern Pacific sea surface temperature on the double-ITCZ bias in NCAR CESM1

NASA Astrophysics Data System (ADS)

Song, F.; Zhang, G. J.

2016-12-01

The double-intertropical convergence zone (ITCZ) is a long-standing bias in the coupled general circulation models (CGCMs). The warm biases in southeastern Pacific (SEP) sea surface temperature (SST) are also evident in many CGCMs. In this study, the role of SEP SST in the double-ITCZ is investigated by prescribing the observed SEP SST in the Community Earth System Model version 1 (CESM1). Both the double-ITCZ and dry equator problems are significantly improved with SEP SST prescribed. The colder SST over the SEP increases the southeasterly winds extending outside the prescribed SST region, cooling the ocean there via increased evaporation. The enhanced descending motion over the SEP strengthens the Walker circulation, so the low-level wind convergence in the tropical western Pacific is increased. The reduced wind speed leads to warmer SST and stronger convection there. The stronger convection in turn leads to more cloud and reduces the incoming solar radiation, cooling the SST. These competing effects between radiative heat flux and latent heat flux make the atmospheric heat flux secondary to the ocean dynamics in the western Pacific warming. The increased easterly winds over the equatorial Pacific enhance upwelling and shoal the thermocline over the eastern Pacific. This Bjerknes feedback plays an important role in the improvement of dry equator. The changes of surface wind and wind curl also lead to weaker South Equatorial Countercurrent and stronger South Equatorial Current, preventing the warm water from expanding eastward, thereby improving both the double-ITCZ and dry equator.

Hydrologic monitoring using open-source Arduino logging platforms in a socio-hydrological system of the drought-prone tropics, Guanacaste, Costa Rica

NASA Astrophysics Data System (ADS)

Hund, S. V.; Johnson, M. S.; Steyn, D. G.; Keddie, T.; Morillas, L.

2015-12-01

Water supply is highly disputed in the tropics of northwestern Costa Rica where rainfall exhibits high seasonal variability and long annual dry seasons. Water shortages are common during the dry season, and water conflicts emerge between domestic water users, intensively irrigated agriculture, the tourism industry, and ecological flows. Climate change may further increase the variability of precipitation and the risk for droughts, and pose challenges for small rural agricultural communities experiencing water stress. To adapt to seasonal droughts and improve resilience of communities to future changes, it is essential to increase understanding of interactions between components of the coupled hydrological-social system. Yet, hydrological monitoring and data on water use within developing countries of the humid tropics is limited. To address these challenges and contribute to extended monitoring networks, low-cost and open-source monitoring platforms were developed based off Arduino microelectronic boards and software and combined with hydrological sensors to monitor river stage and groundwater levels in two watersheds of Guanacaste, Costa Rica. Hydrologic monitoring stations are located in remote locations and powered by solar panels. Monitoring efforts were made possible through collaboration with local rural communities, and complemented with a mix of digitized water extraction data and community water use narratives to increase understanding of water use and challenges. We will present the development of the Arduino logging system, results of water supply in relation to water use for both the wet and dry season, and discuss these results within a socio-hydrological system context.

Volatile accretion history of the terrestrial planets and dynamic implications.

PubMed

Albarède, Francis

2009-10-29

Accretion left the terrestrial planets depleted in volatile components. Here I examine evidence for the hypothesis that the Moon and the Earth were essentially dry immediately after the formation of the Moon-by a giant impact on the proto-Earth-and only much later gained volatiles through accretion of wet material delivered from beyond the asteroid belt. This view is supported by U-Pb and I-Xe chronologies, which show that water delivery peaked approximately 100 million years after the isolation of the Solar System. Introduction of water into the terrestrial mantle triggered plate tectonics, which may have been crucial for the emergence of life. This mechanism may also have worked for the young Venus, but seems to have failed for Mars.

Volatile accretion history of the Earth.

PubMed

Wood, B J; Halliday, A N; Rehkämper, M

2010-10-28

It has long been thought that the Earth had a protracted and complex history of volatile accretion and loss. Albarède paints a different picture, proposing that the Earth first formed as a dry planet which, like the Moon, was devoid of volatile constituents. He suggests that the Earth's complement of volatile elements was only established later, by the addition of a small veneer of volatile-rich material at ∼100 Myr (here and elsewhere, ages are relative to the origin of the Solar System). Here we argue that the Earth's mass balance of moderately volatile elements is inconsistent with Albarède's hypothesis but is well explained by the standard model of accretion from partially volatile-depleted material, accompanied by core formation.

Biomass waste-to-energy valorisation technologies: a review case for banana processing in Uganda.

PubMed

Gumisiriza, Robert; Hawumba, Joseph Funa; Okure, Mackay; Hensel, Oliver

2017-01-01

Uganda's banana industry is heavily impeded by the lack of cheap, reliable and sustainable energy mainly needed for processing of banana fruit into pulp and subsequent drying into chips before milling into banana flour that has several uses in the bakery industry, among others. Uganda has one of the lowest electricity access levels, estimated at only 2-3% in rural areas where most of the banana growing is located. In addition, most banana farmers have limited financial capacity to access modern solar energy technologies that can generate sufficient energy for industrial processing. Besides energy scarcity and unreliability, banana production, marketing and industrial processing generate large quantities of organic wastes that are disposed of majorly by unregulated dumping in places such as swamps, thereby forming huge putrefying biomass that emit green house gases (methane and carbon dioxide). On the other hand, the energy content of banana waste, if harnessed through appropriate waste-to-energy technologies, would not only solve the energy requirement for processing of banana pulp, but would also offer an additional benefit of avoiding fossil fuels through the use of renewable energy. The potential waste-to-energy technologies that can be used in valorisation of banana waste can be grouped into three: Thermal (Direct combustion and Incineration), Thermo-chemical (Torrefaction, Plasma treatment, Gasification and Pyrolysis) and Biochemical (Composting, Ethanol fermentation and Anaerobic Digestion). However, due to high moisture content of banana waste, direct application of either thermal or thermo-chemical waste-to-energy technologies is challenging. Although, supercritical water gasification does not require drying of feedstock beforehand and can be a promising thermo-chemical technology for gasification of wet biomass such as banana waste, it is an expensive technology that may not be adopted by banana farmers in Uganda. Biochemical conversion technologies are reported to be more eco-friendly and appropriate for waste biomass with high moisture content such as banana waste. Uganda's banana industrialisation is rural based with limited technical knowledge and economic capability to setup modern solar technologies and thermo-conversions for drying banana fruit pulp. This review explored the advantages of various waste-to-energy technologies as well as their shortfalls. Anaerobic digestion stands out as the most feasible and appropriate waste-to-energy technology for solving the energy scarcity and waste burden in banana industry. Finally, potential options for the enhancement of anaerobic digestion of banana waste were also elucidated.

Resistance of bacterial endospores to outer space for planetary protection purposes--experiment PROTECT of the EXPOSE-E mission.

PubMed

Horneck, Gerda; Moeller, Ralf; Cadet, Jean; Douki, Thierry; Mancinelli, Rocco L; Nicholson, Wayne L; Panitz, Corinna; Rabbow, Elke; Rettberg, Petra; Spry, Andrew; Stackebrandt, Erko; Vaishampayan, Parag; Venkateswaran, Kasthuri J

2012-05-01

Spore-forming bacteria are of particular concern in the context of planetary protection because their tough endospores may withstand certain sterilization procedures as well as the harsh environments of outer space or planetary surfaces. To test their hardiness on a hypothetical mission to Mars, spores of Bacillus subtilis 168 and Bacillus pumilus SAFR-032 were exposed for 1.5 years to selected parameters of space in the experiment PROTECT during the EXPOSE-E mission on board the International Space Station. Mounted as dry layers on spacecraft-qualified aluminum coupons, the "trip to Mars" spores experienced space vacuum, cosmic and extraterrestrial solar radiation, and temperature fluctuations, whereas the "stay on Mars" spores were subjected to a simulated martian environment that included atmospheric pressure and composition, and UV and cosmic radiation. The survival of spores from both assays was determined after retrieval. It was clearly shown that solar extraterrestrial UV radiation (λ≥110 nm) as well as the martian UV spectrum (λ≥200 nm) was the most deleterious factor applied; in some samples only a few survivors were recovered from spores exposed in monolayers. Spores in multilayers survived better by several orders of magnitude. All other environmental parameters encountered by the "trip to Mars" or "stay on Mars" spores did little harm to the spores, which showed about 50% survival or more. The data demonstrate the high chance of survival of spores on a Mars mission, if protected against solar irradiation. These results will have implications for planetary protection considerations.

Investigating aerosol properties in Peninsular Malaysia via the synergy of satellite remote sensing and ground-based measurements

NASA Astrophysics Data System (ADS)

Kanniah, Kasturi Devi; Lim, Hui Qi; Kaskaoutis, Dimitris G.; Cracknell, Arthur P.

2014-03-01

Spatio-temporal variation and trends in atmospheric aerosols as well as their impact on solar radiation and clouds are crucial for regional and global climate change assessment. These topics are not so well-documented over Malaysia, the fact that it receives considerable amounts of pollutants from both local and trans-boundary sources. The present study aims to analyse the spatio-temporal evolution and decadal trend of Aerosol Optical Depth (AOD) from Terra and Aqua MODIS sensors, to identify different types and origin of aerosols and explore the link between aerosols and solar radiation. AOD and fine-mode fraction (FMF) products from MODIS, AOD and Ångström Exponent (AE) values from AERONET stations along with ground-based PM10 measurements and solar radiation recordings at selected sites in Peninsular Malaysia are used for this scope. The MODIS AODs exhibit a wide spatio-temporal variation over Peninsular Malaysia, while Aqua AOD is consistently lower than that from Terra. The AOD shows a neutral-to-declining trend during the 2000s (Terra satellite), while that from Aqua exhibits an increasing trend (~ 0.01 per year). AERONET AODs exhibit either insignificant diurnal variation or higher values during the afternoon, while their short-term availability does not allow for a trend analysis. Moreover, the PM10 concentrations exhibit a general increasing trend over the examined locations. The sources and destination of aerosols are identified via the HYSPLIT trajectory model, revealing that aerosols during the dry season (June to September) are mainly originated from the west and southwest (Sumatra, Indonesia), while in the wet season (November to March) they are mostly associated with the northeast monsoon winds from the southern China Sea. Different aerosol types are identified via the relationship of AOD with FMF, revealing that the urban and biomass-burning aerosols are the most abundant over the region contributing to a significant reduction (~- 0.21 MJ m- 2) of the solar radiation.

Foehn-induced effects on dust pollution, frontal clouds and solar radiation in the Dead Sea valley

NASA Astrophysics Data System (ADS)

Kishcha, Pavel; Starobinets, Boris; Alpert, Pinhas; Kaplan, Michael

2017-04-01

The significant drying up of the Dead Sea over the past 40 years has led to an increase in an exposed area contributing to local dust pollution. Measurements show that, sometimes, in the Dead Sea valley, dust pollution can reach extreme concentrations up to several thousands of micrograms per cubic meters. Our analysis of a meteorological situation shows that a foehn phenomenon can be a causal factor for the aforementioned extreme local dust concentration. This foehn phenomenon creates strong warm and dry winds, which are accompanied by air turbulence and temperature inversion. In our study, foehn-induced effects on dust pollution, frontal clouds and solar radiation were analyzed over the Judean Mountains ( 1000 m) and over the Dead Sea valley (-420 m), using high-resolution numerical simulations and in-situ observations at meteorological stations located across the mountain ridge. An extreme dust episode occurring on March 22, 2013, was analyzed, which was characterized by measured surface dust concentrations of up to 7000 µg m-3 in the Dead Sea valley. We simulated this foehn phenomenon with the 3-km resolution COSMO-ART model. Our analysis has shown that the foehn phenomenon could be observed even over the relatively low Judean Mountains. This analysis was based on various meteorological, pyranometer, radar, and aerosol measurements together with high-resolution model data. In the Dead Sea valley, the maximum aerosol optical depth (AOD) did not coincide with the maximum surface dust concentration. This lack of coincidence indicates difficulties in using satellite-based AOD for initializing dust concentration within numerical forecast systems over this region with complex terrain. In the western Dead Sea valley, strong foehn winds of over 20 m/s were accompanied by maximal air turbulence leading to maximal local dust emissions. Thus, the model showed that, by creating significant turbulence, the foehn phenomenon intensified the saltation (bombardment) mechanism of local dust generation in the western Dead Sea valley. In addition, the foehn-induced pronounced temperature inversion trapped dust particles beneath this inversion. These two factors caused the measured extreme surface dust concentration in the Dead Sea valley on the specified day. Radar data on March 22 showed a passage of multi-layer frontal cloudiness through the area of the Dead Sea valley leading to a sharp drop in noon solar radiation. The strong descending airflow over the downwind side of the Judean Mountains significantly influenced the frontal cloudiness leading to the formation of a cloud-free band over the Dead Sea valley.

Zeolite Formation and Weathering Processes in Dry Valleys of Antartica: Martian Analogs

NASA Technical Reports Server (NTRS)

Gibson, E. K., Jr.; Wentworth, S. J.; McKay, D. S.; Socki, R. A.

2004-01-01

Terrestrial weathering processes in cold-desert climates such as the Dry Valleys of Antarctica may provide an excellent analog to chemical weathering and diagenesis of soils on Mars. Detailed studies of soil development and the chemical and mineralogical alterations occurring within soil columns in Wright Valley, Antarctica show incredible complexity in the upper meter of soil. Previous workers noted the ice-free Dry Valleys are the best terrestrial approximations to contemporary Mars. Images returned from the Pathfinder and Spirit landers show similarities to surfaces observed within the Dry Valleys. Similarities to Mars that exist in these valleys are: mean temperatures always below freezing (-20 C), no rainfall, sparse snowfall-rapidly removed by sublimation, desiccating winds, diurnal freeze-thaw cycles (even during daylight hours), low humidity, oxidative environment, relatively high solar radiation and low magnetic fields . The Dry Valley soils contain irregular distributions and low abundances of soil microorganisms that are somewhat unusual on Earth. Physical processes-such as sand abrasion-are dominant mechanisms of rock weathering in Antarctica. However, chemical weathering is also an important process even in such extreme climates. For example, ionic migration occurs even in frozen soils along liquid films on individual soil particles. It has also been shown that water with liquid-like properties is present in soils at temperatures on the order of approx.-80 C and it has been observed that the percentage of oxidized iron increases with increasing soil age and enrichments in oxidized iron occurs toward the surface. The presence of evaporates is evident and appear similar to "evaporite sites" within the Pathfinder and Spirit sites. Evaporites indicate ionic migration and chemical activity even in the permanently frozen zone. The presence of evaporates indicates that chemical weathering of rocks and possibly soils has been active. Authogenic zeolites have been identified within the soil columns because they are fragile; i.e. they are euhedral, unabraded, and unfractured, strongly suggesting in situ formation. Their presence in Antarctic samples is another indication that diagenic processes are active in cold-desert environments. The presence of zeolites, and other clays along with halites, sulfates, carbonates, and hydrates are to be expected within the soil columns on Mars at the Gusev and Isidis Planitia regions. The presence of such water-bearing minerals beneath the surface supplies one of the requirements to support biological activity on Mars.

Fruit and fertility in San Juan de la Manguana.

PubMed

Mckenna, N D

1995-01-01

Ana Irsa (Nisoris) Aquina, 39, a mother of seven, grandmother, wife, and voluntary community health facilitator, lives in the Dominican Republic. Nisoris counsels women and their partners about reproductive health, provides child survival information to new mothers, and dispenses common remedies for diarrhea and respiratory infections as well as contraceptives (mainly oral contraceptives and condoms). These supplies are financed by Fundacion para el Desarrollo Communitario (FUDECO), a nongovernmental agency which is a member of the Save the Children alliance. FUDECO's work includes the development of water systems, health services, schools, and soil conservation training. Widespread deforestation in the San Juan area has led to a reduction in self-sufficient farming and a lack of nutrition evidenced by an increase in infant blindness caused by Vitamin A deficiency. To combat this situation, FUDECO has taught the women's group led by Nisoris how to use solar power to dry fruits and vegetables to preserve them for consumption beyond their season. The pilot group has in turn taught six other women's groups and conducted informal product sampling and Vitamin A information sessions in the local market. FUDECO provides supplies and technical expertise. The program has been so successful that the women are exploring packaging options so that they can sell the dried produce.

Candidate Coatings and Dry Traction Drives for Planetary Vehicles

NASA Technical Reports Server (NTRS)

Fusaro, Robert; Oswald, Fred B.

2002-01-01

Robert Fusaro and Fred Oswald of the Mechanical Components Branch discussed 'Candidate Coatings and Dry Traction Drives for Planetary Vehicles'. Vehicles to be designed for exploration of planets and moons of the solar system will require reliable mechanical drives to operate efficiently. Long-term operation of these drives will be challenging because of extreme operating conditions. These extreme conditions include: very high and/or very cold temperatures, wide temperature ranges, dust, vacuum or low-pressure atmospheres, and corrosive environments. Most drives used on Earth involve oil-lubricated gears. However, due to the extreme conditions on planetary surfaces, it may not be advisable or even possible to use oil lubrication. Unfortunately, solid lubricants do not work well when applied to gears because of the high contact stress conditions and large sliding motion between the teeth, which cause wear and limit life. We believe traction drives will provide an attractive alternative to gear drives. Traction drives are composed of rollers that provide geometry more conducive to solid lubrication. Minimal slip occurs in this contact geometry and thus there is very low wear to the solid lubricant. The challenge for these solid-lubricated drives is finding materials or coatings that provide the required long-life while also providing high traction. We seek materials that provide low wear with high friction.

Earth Observation

NASA Image and Video Library

2014-06-05

ISS040-E-008209 (6 June 2014) --- Okavango inland delta in northern Botswana is featured in this image photographed by an Expedition 40 crew member on the International Space Station. The great Okavango delta in the Kalahari Desert is illuminated in the sun?s reflection point in this panorama. Using this sun glint technique, crew members can image fine detail of water bodies. Here the bright line of the Okavango River shows the annual summer flood advancing from the well-watered Angolan Highlands (upper margin) to the delta. Then the flood water slowly seeps across the 150 kilometer-long delta, supplying forests and wetlands, finally reaching the fault-bounded lower margin of the delta in the middle of winter. Most of the water of this large river is used up by the forests, or evaporates in the dry air. Only two percent of the river?s water actually exits the delta. The wetland supports high biodiversity in the middle of the otherwise semiarid Kalahari Desert, and is now one of the most famous tourist sites in Africa. This view also shows the small quantity of water in the Boteti River. Okavango water only reaches the dry lake floors (lower right) in the wettest years. Part of one of the station?s solar arrays is visible at right.

Asynchronous Amazon Forest Canopy Phenology Indicates Adaptation to Both Water and Light Availability

NASA Astrophysics Data System (ADS)

Jones, M. O.; Kimball, J. S.; Nemani, R. R.

2015-12-01

Amazon forests represent nearly half of all tropical vegetation biomass and, through photosynthesis and respiration, annually process more than twice the amount of estimated carbon (CO2) from fossil fuel emissions. Yet the seasonality of Amazon canopy cover, and the extent to which seasonal fluctuations in water availability and photosynthetically active radiation influence these processes, is still poorly understood. Implementing six remotely sensed data sets spanning nine years (2003-2011), with reported field and flux tower data, we show that southern equatorial Amazon forests exhibit a distinctive seasonal signal. Seasonal timing of water availability, canopy biomass growth and net leaf flush are asynchronous in regions with short dry seasons and become more synchronous across a west-to-east longitudinal moisture gradient of increasing dry season length. Forest cover is responsive to seasonal disparities in both water and solar radiation availability, temporally adjusting net leaf flush to maximize use of these generally abundant resources, while reducing drought susceptibility. An accurate characterization of this asynchronous behavior allows for improved understanding of canopy phenology across contiguous tropical forests and their sensitivity to climate variability and drought. These insights can also inform land surface models to provide a more accurate representation of seasonal forest carbon allocation strategies responsive to environmental drivers.

Caribbean-Wide, Long-Term Study of Seagrass Beds Reveals Local Variations, Shifts in Community Structure and Occasional Collapse

PubMed Central

van Tussenbroek, Brigitta I.; Cortés, Jorge; Collin, Rachel; Fonseca, Ana C.; Gayle, Peter M. H.; Guzmán, Hector M.; Jácome, Gabriel E.; Juman, Rahanna; Koltes, Karen H.; Oxenford, Hazel A.; Rodríguez-Ramirez, Alberto; Samper-Villarreal, Jimena; Smith, Struan R.; Tschirky, John J.; Weil, Ernesto

2014-01-01

The CARICOMP monitoring network gathered standardized data from 52 seagrass sampling stations at 22 sites (mostly Thalassia testudinum-dominated beds in reef systems) across the Wider Caribbean twice a year over the period 1993 to 2007 (and in some cases up to 2012). Wide variations in community total biomass (285 to >2000 g dry m−2) and annual foliar productivity of the dominant seagrass T. testudinum (<200 and >2000 g dry m−2) were found among sites. Solar-cycle related intra-annual variations in T. testudinum leaf productivity were detected at latitudes > 16°N. Hurricanes had little to no long-term effects on these well-developed seagrass communities, except for 1 station, where the vegetation was lost by burial below ∼1 m sand. At two sites (5 stations), the seagrass beds collapsed due to excessive grazing by turtles or sea-urchins (the latter in combination with human impact and storms). The low-cost methods of this regional-scale monitoring program were sufficient to detect long-term shifts in the communities, and fifteen (43%) out of 35 long-term monitoring stations (at 17 sites) showed trends in seagrass communities consistent with expected changes under environmental deterioration. PMID:24594732