Thermal analysis of a multi-layer microchannel heat sink for cooling concentrator photovoltaic (CPV) cells

NASA Astrophysics Data System (ADS)

Siyabi, Idris Al; Shanks, Katie; Mallick, Tapas; Sundaram, Senthilarasu

2017-09-01

Concentrator Photovoltaic (CPV) technology is increasingly being considered as an alternative option for solar electricity generation. However, increasing the light concentration ratio could decrease the system output power due to the increase in the temperature of the cells. The performance of a multi-layer microchannel heat sink configuration was evaluated using numerical analysis. In this analysis, three dimensional incompressible laminar steady flow model was solved numerically. An electrical and thermal solar cell model was coupled for solar cell temperature and efficiency calculations. Thermal resistance, solar cell temperature and pumping power were used for the system efficiency evaluation. An increase in the number of microchannel layers exhibited the best overall performance in terms of the thermal resistance, solar cell temperature uniformity and pressure drop. The channel height and width has no effect on the solar cell maximum temperature. However, increasing channel height leads to a reduction in the pressure drop and hence less fluid pumping power.

Numerical and Experimental Investigation on a Thermo-Photovoltaic Module for Higher Efficiency Energy Generation

NASA Astrophysics Data System (ADS)

Karami-Lakeh, Hossein; Hosseini-Abardeh, Reza; Kaatuzian, Hassan

2017-05-01

One major problem of solar cells is the decrease in efficiency due to an increase in temperature when operating under constant irradiation of solar energy. The combination of solar cell and a thermoelectric generator is one of the methods proposed to solve this problem. In this paper, the performance of thermo-photovoltaic system is studied experimentally as well as through numerical simulation. In the experimental part, design, manufacture and test of a novel thermo-photovoltaic system assembly are presented. Results of the assembled system showed that with reduction of one degree (Centigrade) in the temperature of solar cell under investigation, and about 0.2 % increase in the efficiency will be obtained in comparison with given efficiency at that specified temperature. The solar cell in a hybrid-assembled system under two cooling conditions (air cooling and water cooling) obtained an efficiency of 8 % and 9.5 %, respectively, while the efficiency of a single cell under the same radiation condition was 6 %. In numerical simulation part, photo-thermoelectric performance of system was analyzed. Two methods for evaluation of thermoelectric performance were used: average properties and finite element method. Results of simulation also demonstrate an increase in solar cell efficiency in the combined system in comparison with that of the single cell configuration.

Design of Intelligent Power Supply System for Expressway Tunnel

NASA Astrophysics Data System (ADS)

Wang, Li; Li, Yutong; Lin, Zimian

2018-01-01

Tunnel lighting program is one of the key points of tunnel infrastructure construction. As tunnels tend to handle remote locations, power supply line construction generally has been having the distance, investment, high cost characteristics. To solve this problem, we propose a green, environmentally friendly, energy-efficient lighting system. This program uses the piston-wind which cars within tunnel produce as the power and combines with solar energy, physical lighting to achieve it, which solves the problem of difficult and high cost of highway tunnel section, and provides new ideas for the future construction of tunnel power supply.

Modelling the performance of the tapered artery heat pipe design for use in the radiator of the solar dynamic power system of the NASA Space Station

NASA Technical Reports Server (NTRS)

Evans, Austin Lewis

1988-01-01

The paper presents a computer program developed to model the steady-state performance of the tapered artery heat pipe for use in the radiator of the solar dynamic power system of the NASA Space Station. The program solves six governing equations to ascertain which one is limiting the maximum heat transfer rate of the heat pipe. The present model appeared to be slightly better than the LTV model in matching the 1-g data for the standard 15-ft test heat pipe.

Thermodynamic analysis of a combined-cycle solar thermal power plant with manganese oxide-based thermochemical energy storage

NASA Astrophysics Data System (ADS)

Lei, Qi; Bader, Roman; Kreider, Peter; Lovegrove, Keith; Lipiński, Wojciech

2017-11-01

We explore the thermodynamic efficiency of a solar-driven combined cycle power system with manganese oxide-based thermochemical energy storage system. Manganese oxide particles are reduced during the day in an oxygen-lean atmosphere obtained with a fluidized-bed reactor at temperatures in the range of 750-1600°C using concentrated solar energy. Reduced hot particles are stored and re-oxidized during night-time to achieve continuous power plant operation. The steady-state mass and energy conservation equations are solved for all system components to calculate the thermodynamic properties and mass flow rates at all state points in the system, taking into account component irreversibilities. The net power block and overall solar-to-electric energy conversion efficiencies, and the required storage volumes for solids and gases in the storage system are predicted. Preliminary results for a system with 100 MW nominal solar power input at a solar concentration ratio of 3000, designed for constant round-the-clock operation with 8 hours of on-sun and 16 hours of off-sun operation and with manganese oxide particles cycled between 750 and 1600°C yield a net power block efficiency of 60.0% and an overall energy conversion efficiency of 41.3%. Required storage tank sizes for the solids are estimated to be approx. 5-6 times smaller than those of state-of-the-art molten salt systems.

Solar Power Beaming: From Space to Earth

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

Rubenchik, A M; Parker, J M; Beach, R J

Harvesting solar energy in space and power beaming the collected energy to a receiver station on Earth is a very attractive way to help solve mankind's current energy and environmental problems. However, the colossal and expensive 'first step' required in achieving this goal has to-date stifled its initiation. In this paper, we will demonstrate that recent advance advances in laser and optical technology now make it possible to deploy a space-based system capable of delivering 1 MW of energy to a terrestrial receiver station, via a single unmanned commercial launch into Low Earth Orbit (LEO). Figure 1 depicts the overallmore » concept of our solar power beaming system, showing a large solar collector in space, beaming a coherent laser beam to a receiving station on Earth. We will describe all major subsystems and provide technical and economic discussion to support our conclusions.« less

"The Great Solar System Rescue": A Highly Usable Videodisc Program.

ERIC Educational Resources Information Center

Haas, Mary E.

1993-01-01

Describes an interactive problem-solving videodisc program designed for the middle schools. Explains the interdisciplinary nature of the program that includes information from astronomy, geology, history, and meteorology. Contends that the product is an excellent example of well-designed educational software. (CFR)

Tilt to horizontal global solar irradiance conversion: application to PV systems data

NASA Astrophysics Data System (ADS)

Housmans, Caroline; Leloux, Jonathan; Bertrand, Cédric

2017-04-01

Many transposition models have been proposed in the literature to convert solar irradiance on the horizontal plane to that on a tilted plane requiring that at least two of the three solar components (i.e. global, direct and diffuse) are known. When only global irradiance measurements are available, the conversion from horizontal to tilted planes is still possible but in this case transposition models have to be coupled with decomposition models (i.e. models that predict the direct and diffuse components from the global one). Here, two different approaches have been considered to solve the reverse process, i.e. the conversion from tilted to horizontal: (i) one-sensor approach and (ii) multi-sensors approach. Because only one tilted plane is involved in the one-sensor approach, a decomposition model need to be coupled with a transposition model to solve the problem. By contrast, at least two tilted planes being considered in the multi-sensors approach, only a transposition model is required to perform the conversion. First, global solar irradiance measurements recorded on the roof of the Royal Meteorological Institute of Belgium's radiation tower in Uccle were used to evaluate the performance of both approaches. Four pyranometers (one mounted in the horizontal plane and three on inclined surfaces with different tilts and orientations) were involved in the validation exercise. Second, the inverse transposition was applied to tilted global solar irradiance values retrieved from the energy production registered at residential PV systems located in the vicinity of Belgian radiometric stations operated by RMI (for validation purposes).

STDAC: Solar thermal design assistance center annual report fiscal year 1994

NASA Astrophysics Data System (ADS)

The Solar Thermal Design Assistance Center (STDAC) at Sandia is a resource provided by the DOE Solar Thermal Program. The STDAC's major objective is to accelerate the use of solar thermal systems by providing direct technical assistance to users in industry, government, and foreign countries; cooperating with industry to test, evaluate, and develop renewable energy systems and components; and educating public and private professionals, administrators, and decision makers. This FY94 report highlights the activities and accomplishments of the STDAC. In 1994, the STDAC continued to provide significant direct technical assistance to domestic and international organizations in industry, government, and education, Applying solar thermal technology to solve energy problems is a vital element of direct technical assistance. The STDAC provides information on the status of new, existing, and developing solar technologies; helps users screen applications; predicts the performance of components and systems; and incorporates the experience of Sandia's solar energy personnel and facilities to provide expert guidance. The STDAC directly enhances the US solar industry's ability to successfully bring improved systems to the marketplace. By collaborating with Sandia's Photovoltaic Design Assistance Center and the National Renewable Energy Laboratory the STDAC is able to offer each customer complete service in applying solar thermal technology. At the National Solar Thermal Test Facility the STDAC tests and evaluates new and innovative solar thermal technologies. Evaluations are conducted in dose cooperation with manufacturers, and the results are used to improve the product and/or quantify its performance characteristics. Manufacturers, in turn, benefit from the improved design, economic performance, and operation of their solar thermal technology. The STDAC provides cost sharing and in-kind service to manufacturers in the development and improvement of solar technology.

Transformation Systems at NASA Ames

NASA Technical Reports Server (NTRS)

Buntine, Wray; Fischer, Bernd; Havelund, Klaus; Lowry, Michael; Pressburger, TOm; Roach, Steve; Robinson, Peter; VanBaalen, Jeffrey

1999-01-01

In this paper, we describe the experiences of the Automated Software Engineering Group at the NASA Ames Research Center in the development and application of three different transformation systems. The systems span the entire technology range, from deductive synthesis, to logic-based transformation, to almost compiler-like source-to-source transformation. These systems also span a range of NASA applications, including solving solar system geometry problems, generating data analysis software, and analyzing multi-threaded Java code.

HEAP: Heat Energy Analysis Program, a computer model simulating solar receivers. [solving the heat transfer problem

NASA Technical Reports Server (NTRS)

Lansing, F. L.

1979-01-01

A computer program which can distinguish between different receiver designs, and predict transient performance under variable solar flux, or ambient temperatures, etc. has a basic structure that fits a general heat transfer problem, but with specific features that are custom-made for solar receivers. The code is written in MBASIC computer language. The methodology followed in solving the heat transfer problem is explained. A program flow chart, an explanation of input and output tables, and an example of the simulation of a cavity-type solar receiver are included.

A multi-node model for transient heat transfer analysis of stratospheric airships

NASA Astrophysics Data System (ADS)

Alam, Mohammad Irfan; Pant, Rajkumar S.

2017-06-01

This paper describes a seven-node thermal model for transient heat transfer analysis of a solar powered stratospheric airship in floating condition. The solar array is modeled as a three node system, viz., outer layer, solar cell and substrate. The envelope is also modeled in three nodes, and the contained gas is considered as the seventh node. The heat transfer equations involving radiative, infra-red and conductive heat are solved simultaneously using a fourth order Runge-Kutta Method. The model can be used to study the effect of solar radiation, ambient wind, altitude and location of deployment of the airship on the temperature of the solar array. The model has been validated against some experimental data and numerical results quoted in literature. The effect of change in the value of some operational parameters on temperature of the solar array, and hence on its power output is also discussed.

Rapid Development of Gossamer Propulsion for NASA Inner Solar System Science Missions

NASA Technical Reports Server (NTRS)

Young, Roy M.; Montgomery, Edward E.

2006-01-01

Over a two and one-half year period dating from 2003 through 2005, NASA s In-Space Propulsion Program matured solar sail technology from laboratory components to full systems, demonstrated in as relevant a space environment as could feasibly be simulated on the ground. This paper describes the challenges identified; as well as the approaches taken toward solving a broad set of issues spanning material science, manufacturing technology, and interplanetary trajectory optimization. Revolutionary advances in system structural predictive analysis and characterization testing occurred. Also addressed are the remaining technology challenges that might be resolved with further ground technology research, geared toward reducing technical risks associated with future space validation and science missions.

Probabilistic Density Function Method for Stochastic ODEs of Power Systems with Uncertain Power Input

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

Wang, Peng; Barajas-Solano, David A.; Constantinescu, Emil

Wind and solar power generators are commonly described by a system of stochastic ordinary differential equations (SODEs) where random input parameters represent uncertainty in wind and solar energy. The existing methods for SODEs are mostly limited to delta-correlated random parameters (white noise). Here we use the Probability Density Function (PDF) method for deriving a closed-form deterministic partial differential equation (PDE) for the joint probability density function of the SODEs describing a power generator with time-correlated power input. The resulting PDE is solved numerically. A good agreement with Monte Carlo Simulations shows accuracy of the PDF method.

Design of solar adsorption refrigeration system with CPC and study on the heat and mass transfer performance

NASA Astrophysics Data System (ADS)

Du, W. P.; Li, M.; Wang, Y. F.; He, J. H.; He, J. X.

2017-11-01

To overcome the problem that the heat source temperature is limited and the lower part of the adsorption tube cannot effectively absorb the solar radiation when solar radiation as the heat source of the adsorption refrigeration system. From the perspective of enhancing the adsorption refrigeration unit tube to absorb solar radiation, thereby strengthening the heat transfer characteristic of adsorption bed, which can improve the efficiency of the refrigeration unit refrigerating capacity and system refrigeration efficiency. Solar adsorption refrigeration system based on CPC was designed and constructed in this paper. The heat and mass transfer performance of the adsorption refrigeration system were studied. The experimental results show that the temperature of the adsorption bed with parabolic concentrating structure can rise to 100°C under low irradiation condition. When the irradiation intensity is 600 w/m2 and 400 w/m2, the average temperature rising to desorption temperature reaches 0.67°C and 0.50°C, respectively. It can effectively solve the problem that the conventional adsorption bed is difficult to reach the required desorption temperature due to the low power density of the sunlight. In the experiment, the system COP were 0.166 and 0.143 when the system in the irradiance of 600 w/m2 and 400 w/m2.

SOLVE: a small spacecraft for near lunar environment exploration

NASA Astrophysics Data System (ADS)

Ritter, B.; Karatekin, Ö.; Gerbal, N.; Van Hove, B.; Carrasco, J.; Ranvier, S.; De Keyser, J.

2017-09-01

SOLVE (Small spacecraft fOr near Lunar enViroment Exploration) is a novel mission proposal to employ a 12U CubeSat which will be deployed by a lunar orbiter providing transportation and data relay services. SOLVE will characterize the Lunar environment by studying the complex set of interactions between radiation, illumination, plasma, magnetic field and dust in dependence of altitude. It will decrease its orbit gradually from 500 km altitude in a controlled way until it finally reaches the surface with an attempt to land softly. Besides the above-mentioned geophysical variables, the radiation environment relevant to humans will be measured along the trajectory by detecting highly penetrating ionizing particles (GCRs and SEPs). SOLVE will provide a unique opportunity for demonstration of new and innovative technologies. It will have propulsion systems enabling high Delta-V maneuvers and state-of-art attitude determination and Control System (ADCS) of relevance to future CubeSat missions. Demonstration of small landers for the Moon would open new science opportunities and exploration possibilities that may lead to future geophysical network stations on the Moon as well as other solar system bodies.

The Energy Problem: What the Helios Project Can Do About it (LBNL Science at the Theater)

ScienceCinema

Chu, Steven

2018-06-15

The energy problem is one of the most important issues that science and technology has to solve. Nobel laureate and Berkeley Lab Director Steven Chu proposes an aggressive research program to transform the existing and future energy systems of the world away from technologies that emit greenhouse gases. Berkeley Lab's Helios Project concentrates on renewable fuels, such as biofuels, and solar technologies, including a new generation of solar photovoltaic cells and the conversion of electricity into chemical storage to meet future demand.

The early evolution of Jupiter in the absence of solar tidal forces

NASA Astrophysics Data System (ADS)

Schofield, N.; Woolfson, M. M.

1982-03-01

The early evolution of a Jupiter-like protoplanet is simulated by constructing a physically detailed computer-based model which solves the equations of hydrodynamics and radiative energy transfer for the spherically symmetric case. The model is specifically developed to study the initial and boundary conditions relevant to the capture theory for the origin of the solar system. It is found that the absence of an external medium promotes the rapid expansion of surface material which is enhanced by solar irradiation. Only when the Jeans criterion is less than 0.8 does a spontaneous hydrodynamic collapse of the interior allow a substantial proportion of the protoplanet to condense to planetary densities.

Complex Mobile Independent Power Station for Urban Areas

NASA Astrophysics Data System (ADS)

Tunik, A. A.; Tolstoy, M. Y.

2017-11-01

A new type of a complex mobile independent power station developed in the Department of Engineering Communications and Life-Support Systems of Irkutsk National Research Technical University, is presented in this article. This station contains only solar panel, wind turbine, accumulator, diesel generator and microbial fuel cell for to produce electric energy, heat pump and solar collector to generate heat energy and also wastewater treatment plant and new complex control system. The complex mobile independent power station is intended for full power supply of a different kind of consumers located even in remote areas thus reducing their dependence from centralized energy supply systems, decrease the fossil fuel consumption, improve the environment of urban areas and solve the problems of the purification of industrial and municipal wastewater.

Assessing the Operational Resilience of Electrical Distribution Systems

DTIC Science & Technology

2017-09-01

as solar, hydro, wind , nuclear, or gas turbine power plants, produce electricity. Transmission systems move electricity in bulk from the originating...us. As I continue in my career I will consistently seek to emulate your attention to detail and ability to quickly frame and solve a problem . Thank...generation facility can cause problems (Knaus, 2017). Disruptions to transmission systems, either from the loss of a high-voltage line or a substation, can

Jovian Small Orbiter for Magnetospheric and Auroral Studies

NASA Astrophysics Data System (ADS)

Takashima, T.; Kasaba, Y.; Misawa, H.; Kawaguchi, J.

2005-12-01

Solar-Sail Project to have been examined by ISAS/JAXA as an engineering mission has a possibility of a small probe into the Jovian orbit. This paper summarizes the basic design of Jovian magnetospheric and auroral studies by this small chance. The large-scale Jovian mission has been a hope since the 1970s when the examinations of planetary exploration were started in Japan. In the one of plans, the largest planet in the solar system would be solved by two main objectives: (1) Structure of a gas planet: the internal & atmospheric structures of a gas planet which could not become a star (following the objectives of Planet-C and BepiColombo). (2) Jovian-type magnetosphere: the process of a pulsar-like magnetosphere with the strongest magnetospheric activities in the solar system (following the objectives of BepiColombo and SCOPE). The small polar-orbit orbiter in Solar-Sail Project aims to establish the feasibility of such future outer planet missions by ISAS/JAXA. It aims the former target in its limited resources.

An Experimental Study on the Deployment Behavior of Membrane Structure under Spin Motion

NASA Astrophysics Data System (ADS)

Murakami, T.

load fuel, so to speak, is an ideal propellant system. As a large film is deployed in the space, solar radiation presses it. However, force of solar radiation is tiny, and so it is necessary for it to have a large square in order to use for propulsive force. As larger it becomes, bigger the weigh is. For realizing good efficient Solar Sail it is indispensable to develop a material. sail spacecraft mission realistic. However, to install a solar sail in the real mission, it is found that there are a lot of problems to be solved. Among them is a technology of deployment. attitude stability by rotating a film constantly. It is true that there are some difficulties to change an attitude, still in general, interplanetary missions does not require frequent attitude change. So the solar sail can be realistic if the mission is interplanetary. velocity, the estimation of a necessary deployment force, and the influence of outer force acting to the film. Moreover, it is necessary to consider a shape after deployment because of using it as a propellant system. That is to say, as larger difference from an ideal circular shape is, lower the efficiency as a propellant system is. numerical simulation, but also micro-gravity experiment. In numerical simulation membrane should be modeled carefully, because a dynamics of a film deployment is transitional and includes a large transformation. In this report a simple model which consists of many rigid boards is dealt with. A film is approximated to an aggregate of tiny rigid boards and the shape is calculated by solving additional force of each board. For showing a validity of this modeling, micro-gravity experiment is necessary to be conducted. Because there is a limitation of space and an experiment is conducted by using a small scaling model, similar parameters should be selected carefully.

Solar-pumped solid state Nd lasers

NASA Technical Reports Server (NTRS)

Williams, M. D.; Zapata, L.

1985-01-01

Solid state neodymium lasers are considered candidates for space-based polar-pumped laser for continuous power transmission. Laser performance for three different slab laser configurations has been computed to show the excellent power capability of such systems if heat problems can be solved. Ideas involving geometries and materials are offered as potential solutions to the heat problem.

Studies of the major planet satellite systems

NASA Technical Reports Server (NTRS)

Frey, H.; Lowman, P. D.

1974-01-01

A summary is presented of the available data on the satellites of the major planets, including the currently most plausible models for several observed phenomena, for the planning of spacecraft missions to these objects. Some of the important questions likely to be solved by flyby and/or orbital missions to the giant planets are detailed, the importance of these studies to our understanding of the solar system as a whole is indicated.

Solar adaptive optics: specificities, lessons learned, and open alternatives

NASA Astrophysics Data System (ADS)

Montilla, I.; Marino, J.; Asensio Ramos, A.; Collados, M.; Montoya, L.; Tallon, M.

2016-07-01

First on sky adaptive optics experiments were performed on the Dunn Solar Telescope on 1979, with a shearing interferometer and limited success. Those early solar adaptive optics efforts forced to custom-develop many components, such as Deformable Mirrors and WaveFront Sensors, which were not available at that time. Later on, the development of the correlation Shack-Hartmann marked a breakthrough in solar adaptive optics. Since then, successful Single Conjugate Adaptive Optics instruments have been developed for many solar telescopes, i.e. the National Solar Observatory, the Vacuum Tower Telescope and the Swedish Solar Telescope. Success with the Multi Conjugate Adaptive Optics systems for GREGOR and the New Solar Telescope has proved to be more difficult to attain. Such systems have a complexity not only related to the number of degrees of freedom, but also related to the specificities of the Sun, used as reference, and the sensing method. The wavefront sensing is performed using correlations on images with a field of view of 10", averaging wavefront information from different sky directions, affecting the sensing and sampling of high altitude turbulence. Also due to the low elevation at which solar observations are performed we have to include generalized fitting error and anisoplanatism, as described by Ragazzoni and Rigaut, as non-negligible error sources in the Multi Conjugate Adaptive Optics error budget. For the development of the next generation Multi Conjugate Adaptive Optics systems for the Daniel K. Inouye Solar Telescope and the European Solar Telescope we still need to study and understand these issues, to predict realistically the quality of the achievable reconstruction. To improve their designs other open issues have to be assessed, i.e. possible alternative sensing methods to avoid the intrinsic anisoplanatism of the wide field correlation Shack-Hartmann, new parameters to estimate the performance of an adaptive optics solar system, alternatives to the Strehl and the Point Spread Function used in night time adaptive optics but not really suitable to the solar systems, and new control strategies more complex than the ones used in nowadays solar Multi Conjugate Adaptive Optics systems. In this paper we summarize the lessons learned with past and current solar adaptive optics systems and focus on the discussion on the new alternatives to solve present open issues limiting their performance.

Forbidden mass ranges for shower meteoroids

NASA Astrophysics Data System (ADS)

Moorhead, Althea V.

2017-10-01

Burns et al. (1979) use the parameter β to describe the ratio of radiation pressure to gravity for a particle in the Solar System. The central potential that these particles experience is effectively reduced by a factor of (1 - β), which in turn lowers the escape velocity. Burns et al. (1979) derived a simple expression for the value of β at which particles ejected from a comet follow parabolic orbits and thus leave the Solar System; we expand on this to derive an expression for critical β values that takes ejection velocity into account, assuming geometric optics. We use our expression to compute the critical β value and corresponding mass for cometary ejecta leading, trailing, and following the parent comet’s nucleus for 10 major meteor showers. Finally, we numerically solve for critical β values in the case of non-geometric optics. These values determine the mass regimes within which meteoroids are ejected from the Solar System and therefore cannot contribute to meteor showers.

Forbidden Mass Ranges for Shower Meteoroids

NASA Technical Reports Server (NTRS)

Moorhead, Althea V.

2017-01-01

Burns et al. (1979) use the parameter beta to describe the ratio of radiation pressure to gravity for a particle in the Solar System. The central potential that these particles experience is effectively reduced by a factor of (1- beta ), which in turn lowers the escape velocity. Burns et al. (1979) derived a simple expression for the value of beta at which particles ejected from a comet follow parabolic orbits and thus leave the Solar System; we expand on this to derive an expression for critical beta values that takes ejection velocity into account, assuming geometric optics. We use our expression to compute the critical value and corresponding mass for cometary ejecta leading, trailing, and following the parent comet's nucleus for 10 major meteor showers. Finally, we numerically solve for critical beta values in the case of non-geometric optics. These values determine the mass regimes within which meteoroids are ejected from the Solar System and therefore cannot contribute to meteor showers.

Solar radiation pressure application for orbital motion stabilization near the Sun-Earth collinear libration point

NASA Astrophysics Data System (ADS)

Polyakhova, Elena; Shmyrov, Alexander; Shmyrov, Vasily

2018-05-01

Orbital maneuvering in a neighborhood of the collinear libration point L1 of Sun-Earth system has specific properties, primarily associated with the instability L1. For a long stay in this area of space the stabilization problem of orbital motion requires a solution. Numerical experiments have shown that for stabilization of motion it is requires very small control influence in comparison with the gravitational forces. On the other hand, the stabilization time is quite long - months, and possibly years. This makes it highly desirable to use solar pressure forces. In this paper we illustrate the solar sail possibilities for solving of stabilization problem in a neighborhood L1 with use of the model example.

Dye-sensitized solar cells using ionic liquids as redox mediator

NASA Astrophysics Data System (ADS)

Denizalti, Serpil; Ali, Abdulrahman Khalaf; Ela, Çağatay; Ekmekci, Mesut; Erten-Ela, Sule

2018-01-01

In this research, the influence of ionic liquid on the conversion efficiency, incident photons to converted electrons (IPCE) and performance of fabricated solar cell was investigated using various ionic liquids. Ionic liquids with different substituents and ions were prepared and used as redox mediators in dye-sensitized solar cells (DSSCs). Ionic liquids were characterized 1H and 13C NMR spectra. We practically investigated the performance of ionic liquid salts were used as the mobile ions and found that the efficiencies of DSSCs were increased up to 40% comparing commercial electrolyte system. The ionic liquid compounds were incorporated in DSSCs to obtain an efficient charge transfer, solving the corrosion problem of platinum layer in counter electrode compared to commercial electrolyte.

Improving Operational Effectiveness of Tactical Long Endurance Unmanned Aerial Systems (TALEUAS) by Utilizing Solar Power

DTIC Science & Technology

2014-06-01

Speed xiii TEK Total Energy Compensated TSP traveling salesman problem UAV unmanned aerial vehicle UDP user datagram protocol UKF unscented...discretized map, and use the map to optimally solve the navigation task. The optimal navigation solution utilizes the well-known “ travelling salesman problem ...2 C. FORMULATION OF THE PROBLEM .................................................. 3 D

El Toro Library Solar Heating and Cooling Demonstration Project. Final report

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

Not Available

This report is divided into a number of essentially independent sections, each of which covers a specific topic. The sections, and the topics covered, are as follows. Section 1 provides a brief summary description of the solar energy heating and cooling system including the key final design parameters. Section 2 contains a copy of the final Acceptance Test Report. Section 3 consists of a reduced set of final updated as-built mechanical, electrical, control and instrumentations drawings of the solar energy heating and cooling system. Section 4 provides a summary of system maintenance requirements, in the form of a maintenance schedulemore » which lists necessary maintenance tasks to be performed at monthly, quarterly, semi-annual, and annual intervals. Section 5 contains a series of photographs of the final solar energy system installation, including the collector field and the mechanical equipment room. Section 6 provides a concise summary of system operation and performance for the period of December 1981 through June 1982, as measured, computed and reported by Vitro Laboratories Division of Automation Industries, Inc., for the DOE National Solar Data Network. Section 7 provides a summary of key as-built design parameters, compared with the corresponding original design concept parameters. Section 8 provides a description of a series of significant problems encountered during construction, start-up and check-out of the solar energy heating and cooling system, together with the method employed to solve the problem at the time and/or recommendations for avoiding the problem in the future design of similar systems. Appendices A through H contain the installation, operation and maintenance submittals of the various manufacturers on the major items of equipment in the system. Reference CAPE-2823.« less

Solar receiver with integrated optics

NASA Astrophysics Data System (ADS)

Jiang, Lun; Winston, Roland

2012-10-01

The current challenge for PV/Thermal (PV/T) systems is the reduction of radiation heat loss. Compared to solar thermal selective coating, the solar cells cannot be used as an efficient thermal absorber due to their large emissivity of the encapsulation material. Many commercial PV/T products therefore require a high concentration (more than 10x) to reach an acceptable thermal efficiency for their receivers. Such a concentration system inevitably has to track or semi-track, which induces additional cost and collects only the direct radiation from the sun. We propose a new PV/T design using a vacuum encapsulated thin film cell to solve this problem. The proposed design also collects the diffuse sun light efficiently by using an external compound parabolic concentrator (XCPC). Since the transparent electrode (TCO) of thin film cell is inherently transparent in visible light and reflective beyond infrared, this design uses this layer instead of the conventional solar cell encapsulation as the outmost heat loss surface. By integrating such a vacuum design with a tube shaped absorber, we reduce the complexity of conducting the heat energy and electricity out of the device. A low concentration standalone non-tracking solar collector is proposed in this paper. We also analyzed the thermosyphon system configuration using heat transfer and ray tracing models. The economics of such a receiver are presented.

Analysis of solar ultraviolet lines

NASA Technical Reports Server (NTRS)

Chipman, E.

1971-01-01

The formation of the strongest ultra-violet emission lines of Mg II, O I, C II, and C III in the solar atmosphere is studied in detail. The equations of statistical equilibrium and radiative transfer for each ion are solved using a general computer program that is capable of solving non-LTE line-formation problems for arbitrary atmospheric and atomic models. Interpreting the results in terms of the structure of the solar atmosphere, it is concluded that the HSRA atmosphere has a temperature too low by about 500 K near h = 1100 km and that a temperature plateau with T sub e approximately = 18,000 K and width close to 60 km exists in the upper chromosphere. The structure of the solar atmosphere in the range 20,000 to 100,000 K and the effects of microturbulence on the formation of lines are also investigated. Approximate analytic line-formation problems are solved, and more exact solutions are derived later. An attempt is made to make the best possible fit to the Ca II K line center-to-limb profiles with a one-component atmosphere, with an assumed source function and microturbulent velocity.

Numerical algorithms based on Galerkin methods for the modeling of reactive interfaces in photoelectrochemical (PEC) solar cells

NASA Astrophysics Data System (ADS)

Harmon, Michael; Gamba, Irene M.; Ren, Kui

2016-12-01

This work concerns the numerical solution of a coupled system of self-consistent reaction-drift-diffusion-Poisson equations that describes the macroscopic dynamics of charge transport in photoelectrochemical (PEC) solar cells with reactive semiconductor and electrolyte interfaces. We present three numerical algorithms, mainly based on a mixed finite element and a local discontinuous Galerkin method for spatial discretization, with carefully chosen numerical fluxes, and implicit-explicit time stepping techniques, for solving the time-dependent nonlinear systems of partial differential equations. We perform computational simulations under various model parameters to demonstrate the performance of the proposed numerical algorithms as well as the impact of these parameters on the solution to the model.

Dynamic facade module prototype development for solar radiation prevention in high rise building

NASA Astrophysics Data System (ADS)

Sega Sufia Purnama, Muhammad; Sutanto, Dalhar

2018-03-01

Solar radiation is an aspect that high rise building must avoid. The problem is, if high rise building facade can’t overcome, the solar thermal will come in the building, and its affects on the increasing of room temperature above comfort range. A type of additional facade element that could solve solar thermal in high rise building is adding a sun shading. A dynamic facade is a shade plane in high rise building that can moved or changed on outside condition such as solar movement and intensity. This research will discuss the dynamic facade module prototype development in high rise building in Jakarta. This research will be finish through some step. (1) Static shading shadow simulation. (2) Dynamic facade concept design development. (3) Dynamic shading shadow simulation. (4) Making of dynamic facade module prototype. (5) Field test for the dynamic facade module prototype. The dynamic facade in Jakarta case will be effective to solve solar transmission in high rise building rather than static facade.

Grading NASA's Solar System Exploration Program: A Midterm Report

NASA Technical Reports Server (NTRS)

2008-01-01

The Committee on Assessing the Solar System Exploration Program has reviewed NASA's progress to date in implementing the recommendations made in the National Research Council's (NRC's) solar system exploration decadal survey covering the period 2003-2013, New Frontiers in the Solar System, and in its Mars Architecture report, Assessment of NASA s Mars Architecture 2007-2016. The committee assessed NASA's progress with respect to each individual recommendation in these two reports, assigning an academic-style grade, explaining the rationale for the grade and trend, and offering recommendations for improvement. The committee generally sought to develop recommendations in cases where it determined that the grade, the trend, or both were worrisome and that the achievement of a decadal survey recommendation would require some kind of corrective action on NASA's part. This usually meant that the committee sought to offer a recommendation when the grade was a "C" or lower. However, the committee did offer recommendations in connection with some higher grades when it believed that minor corrective action was possible and desirable. More importantly, the committee did not offer recommendations for some of the activities given lower grades, particularly in the enabling technologies area (Chapter 6), because the committee determined that only the restoration of funding and the development of a strategic technology development program would solve these problems.

Graphene-based Recyclable Photo-Absorbers for High-Efficiency Seawater Desalination.

PubMed

Wang, Xiangqing; Ou, Gang; Wang, Ning; Wu, Hui

2016-04-13

Today's scientific advances in water desalination dramatically increase our ability to transform seawater into fresh water. As an important source of renewable energy, solar power holds great potential to drive the desalination of seawater. Previously, solar assisted evaporation systems usually relied on highly concentrated sunlight or were not suitable to treat seawater or wastewater, severely limiting the large scale application of solar evaporation technology. Thus, a new strategy is urgently required in order to overcome these problems. In this study, we developed a solar thermal evaporation system based on reduced graphene oxide (rGO) decorated with magnetic nanoparticles (MNPs). Because this material can absorb over 95% of sunlight, we achieved high evaporation efficiency up to 70% under only 1 kW m(-2) irradiation. Moreover, it could be separated from seawater under the action of magnetic force by decorated with MNPs. Thus, this system provides an advantage of recyclability, which can significantly reduce the material consumptions. Additionally, by using photoabsorbing bulk or layer materials, the deposition of solutes offen occurs in pores of materials during seawater desalination, leading to the decrease of efficiency. However, this problem can be easily solved by using MNPs, which suggests this system can be used in not only pure water system but also high-salinity wastewater system. This study shows good prospects of graphene-based materials for seawater desalination and high-salinity wastewater treatment.

Baby Stars in Orion Solve Solar System Mystery

NASA Technical Reports Server (NTRS)

Wanjek, Christopher

2003-01-01

What do X-rays, meteoroids, infant stars in the Orion Nebula, and our solar system have in common? Perhaps much more than anyone thought. Eric Feigelson of Penn State University stumbled onto a connection one day while his thoughts were far from the solar system, turned toward the vibrant neighborhood of young stars, hot gas, and caliginous dust of the Orion Nebula. This nebula, 1500 light-years away, is visible to the naked eye in the constellation Orion, a gem to behold with a good pair of binoculars or a telescope under dark skies. In Orion, Feigelson inadvertently found a possible solution to a long-standing mystery about our own solar system: the presence of exotic isotopes locked away in meteoroids. Scientists have assumed that these short-lived isotopes - special forms of atomic nuclei, such as aluminum-26 and calcium-41 - were transported here by a nearby supernova. Only tenuous evidence for such an explosion exists, but what else could have made the isotopes? The isotopes are about as old as the solar system, and the Sun couldn t possibly have been powerful enough to create them. Well, maybe we need to give the Sun a little more credit. Feigelson found that very young, midsized stars in the Orion Nebula - in the same stellar class as our Sun except they are only a million years old - produce powerful flares visible in X-rays. His team spotted these X-ray flares with the Chandra X-Ray Observatory. These baby-tantrum flares are indeed energetic enough to forge heavy isotopes, Feigelson says. If the infant stars in Orion can do it now, then our Sun could have done the same when the solar system was forming about 4.5 billion years ago, when the Sun itself was only a few million years old.

TIMED/GUVI Observations of Aurora, Ionosphere, Thermosphere and Solar EUV Variations

NASA Astrophysics Data System (ADS)

Zhang, Y.; Paxton, L. J.; Schaefer, R. K.

2017-12-01

The FUV (100-200 nm) emissions from the ionosphere and thermosphere carry rich information of the density and composition of the IT system, aurora and solar EUV flux. The key emissions include atomic hydrogen line (121.6nm), atomic oxygen lines (e.g. 130.4, 135.6, 164.1 nm), atomic nitrogen lines (e.g. 120.0, 149.3, 174.3 nm), molecular nitrogen bands (LBH and VK bands) and nitric oxide ɛ bands. TIMED/GUVI data cover the nearly full FUV range and generate many space weather products (ionosphere, thermosphere, aurora and solar EUV) that extend the products from other missions (such as NASA GOLD and ICON) and help to solve some of MIT (Magnetosphere-Ionosphere-Thermosphere) science problems and serve as validation data sources for models.

Cutting-edge Kinetic Physics with Parker Solar Probe and Solar Orbiter: The Arbitrary Linear Plasma Solver (ALPS)

NASA Astrophysics Data System (ADS)

Verscharen, D.; Klein, K. G.; Chandran, B. D. G.; Stevens, M. L.; Salem, C. S.; Bale, S. D.

2017-12-01

The Arbitrary Linear Plasma Solver (ALPS) is a parallelized numerical code that solves the dispersion relation in a hot (even relativistic) magnetized plasma with an arbitrary number of particle species with arbitrary gyrotropic equilibrium distribution functions for any direction of wave propagation with respect to the background field. In this way, ALPS retains generality and overcomes the shortcomings of previous (bi-)Maxwellian solvers for the plasma dispersion relations. The unprecedented high-resolution particle and field data products from Parker Solar Probe (PSP) and Solar Orbiter (SO) will require novel theoretical tools. ALPS is one such tool, and its use will make possible new investigations into the role of non-Maxwellian distributions in the near-Sun solar wind. It can be applied to numerous high-velocity-resolution systems, ranging from current space missions to numerical simulations. We will briefly discuss the ALPS algorithm and demonstrate its functionality based on previous solar-wind measurements. We will then highlight our plans for future applications of ALPS to PSP and SO observations.

Zinc Bromide Flow Battery Installation for Islanding and Backup Power

DTIC Science & Technology

2017-08-09

predictably is in place. The ability to control generation has become more difficult with the increase of RE systems such as solar PV and wind turbines ...Both PV and wind systems generate power based on unpredictable cycles of nature. At very low levels of RE penetration the grid can be balanced by...Page Intentionally Left Blank 15 5.0 TEST DESIGN This goal of this demonstration was to solve two main problems . The first

Orbital Space Solar Power Option for a Lunar Village

NASA Technical Reports Server (NTRS)

Johnson, Les

2017-01-01

One of the most significant challenges to the implementation of a continuously manned lunar base is power. During the lunar day (14 Earth days), it is conceptually simple to deploy solar arrays to generate the estimated 35 kilowatts of continuous power required. However, generating this level of power during the lunar night (also 14 Earth days) has been an extremely difficult problem to solve. Conventional solutions range from the requirement that the base be located at the lunar south pole so as to take advantage of the continuous sunshine available there to developing a space-qualified nuclear reactor and power plant to generate the needed energy. There is a third option: Use the soon-to-be-available Space Launch System to place a space based solar power station in lunar orbit that would beam the needed energy to the lunar base. Several detailed studies have been performed by NASA, universities and others looking at the lunar south pole for locating the base. The results are encouraging: by taking advantage of the moon's orbital tilt, large solar arrays can be deployed there to track the sun continuously and generate the power needed to sustain the base. The problem with this approach is inherent to its design: it will only work at the lunar south pole. There is no other site on the Moon with geometry favorable to generating continuous solar power. NASA has also considered the development of a compact fission reactor and power plant to generate the needed power, allowing the base to be sited anywhere on the Moon. The problem with this approach is that there are no space fission reactors available, none are being planned and the cost of developing one is prohibitively expensive. Using an orbiting space based solar power station to generate electrical power and beam it to a base sited anywhere on the moon should therefore be considered. The technology to collect sunlight, generate greater than the estimated 35 kilowatts of power, and beam it to the surface using microwaves is available today. The problem with this concept in the past would have been the mass and packaging volume (for launch) required to put such a system in place in lunar orbit. This problem is potentially solved with the advent of the Space Launch System (SLS). The SLS, with its 70 mT launch capacity, it more than capable of placing such a system into lunar orbit in a single launch. This paper will examine the potential use of an SLS-launched, space solar power system in lunar orbit as the primary power source for a first-generation, continuously-occupied lunar base and compare it with the other power generation and storage options previously considered.

Three-Fluid Magnetohydrodynamic Modeling of the Solar Wind in the Outer Heliosphere

NASA Technical Reports Server (NTRS)

Usmanov, Arcadi V.; Goldstein, Melvyn L.; Matthaeus, William H.

2011-01-01

We have developed a three-fluid, fully three-dimensional magnetohydrodynamic model of the solar wind plasma in the outer heliosphere as a co-moving system of solar wind protons, electrons, and interstellar pickup protons, with separate energy equations for each species. Our approach takes into account the effects of electron heat conduction and dissipation of Alfvenic turbulence on the spatial evolution of the solar wind plasma and interplanetary magnetic fields. The turbulence transport model is based on the Reynolds decomposition of physical variables into mean and fluctuating components and uses the turbulent phenomenologies that describe the conversion of fluctuation energy into heat due to a turbulent cascade. We solve the coupled set of the three-fluid equations for the mean-field solar wind and the turbulence equations for the turbulence energy, cross helicity, and correlation length. The equations are written in the rotating frame of reference and include heating by turbulent dissipation, energy transfer from interstellar pickup protons to solar wind protons, and solar wind deceleration due to the interaction with the interstellar hydrogen. The numerical solution is constructed by the time relaxation method in the region from 0.3 to 100 AU. Initial results from the novel model are presented.

Thermal analysis of a Phase Change Material for a Solar Organic Rankine Cycle

NASA Astrophysics Data System (ADS)

Iasiello, M.; Braimakis, K.; Andreozzi, A.; Karellas, S.

2017-11-01

Organic Rankine Cycle (ORC) is a promising technology for low temperature power generation, for example for the utilization of medium temperature solar energy. Since heat generated from solar source is variable throughout the day, the implementation of Thermal Energy Storage (TES) systems to guarantee the continuous operation of solar ORCs is a critical task, and Phase Change Materials (PCM) rely on latent heat to store large amounts of energy. In the present study, a thermal analysis of a PCM for a solar ORC is carried out. Three different types of PCMs are analyzed. The energy equation for the PCM is modeled by using the heat capacity method, and it is solved by employing a 1Dexplicit finite difference scheme. The solar source is modeled with a time-variable temperature boundary condition, with experimental data taken from the literature for two different solar collectors. Results are presented in terms of temperature profiles and stored energy. It has been shown that the stored energy depends on the heat source temperature, on the employed PCM and on the boundary conditions. It has been demonstrated that the use of a metal foam can drastically enhance the stored energy due to the higher overall thermal conductivity.

Searching for artificial equilibrium points to place satellites "above and below" L3 in the Sun-Earth system

NASA Astrophysics Data System (ADS)

de Almeida, A. K., Jr.; Prado, A. F. B. A.; Sanchez, D. M.; Yokoyama, T.

2017-10-01

Regarding practical applications of L3 of the Sun-Earth system, there are few studies with the goal of placing a spacecraft at this point, or in orbit around it. One of the main problems in placing a spacecraft near this equilibrium point is the fact that it is located behind the Sun with respect to the Earth. The Sun would be blocking direct communication between the spacecraft and the Earth. The present research gives several options to solve this problem by using a solar sail to place one or two spacecraft above and/or below the Ecliptic plane. This sail could also be used for the mission itself, to collect energy or particles. By using an adequate size, location and attitude of the solar sail, the equilibrium point can be moved from its original location to allow communications between the spacecraft and the Earth. A preliminary study of a solar sail that uses this strategy is shown here.

Thermal modeling of a pressurized air cavity receiver for solar dish Stirling system

NASA Astrophysics Data System (ADS)

Zou, Chongzhe; Zhang, Yanping; Falcoz, Quentin; Neveu, Pierre; Li, Jianlan; Zhang, Cheng

2017-06-01

A solar cavity receiver model for the dish collector system is designed in response to growing demand of renewable energy. In the present research field, no investigations into the geometric parameters of a cavity receiver have been performed. The cylindrical receiver in this study is composed of an enclosed bottom at the back, an aperture at the front, a helical pipe inside the cavity and an insulation layer on the external surface of the cavity. The influence of several critical receiver parameters on the thermal efficiency is analyzed in this paper: cavity inner diameter and cavity length. The thermal model in this paper is solved considering the cavity dimensions as variables. Implementing the model into EES, each parameter influence is separately investigated, and a preliminary optimization method is proposed.

Progress Toward Electrostatic Radiation Shielding of Interplanetary Spacecraft: Strategies, Concepts and Technical Challenges of Human Exploration Beyond Low Earth Orbit

NASA Technical Reports Server (NTRS)

Metzger, Philip T.; Lane, John E.; Youngquist, Robert C.

2004-01-01

The radiation problem is a serious obstacle to solar system exploration. Electrostatic shielding was previously dismissed as unworkable. This was based on the false assumption that radial symmetry is needed to provide isotropic protection. KSC recently demonstrated the feasibility of asymmetric, multipole electrostatic shielding. Combined with passive shielding it might solve the radiation problem

Math Space Mission. [A Product of] the Regional Math Network: A Teacher Invigoration and Curriculum Development Project.

ERIC Educational Resources Information Center

Harvard Univ., Cambridge, MA. Graduate School of Education.

This unit is intended to teach estimation skills in such a way as to be relevant and useful to students as they apply them in various problem-solving activities. The teaching activities feature the earth, exploration into space, and the other worlds in the solar system. The teacher's guide contains four modules. Module I suggests the use of…

Patrol of the short wavelength activity and flares of Sun as star

NASA Astrophysics Data System (ADS)

Afanasiev, I.; Avakyan, S.; Leonov, N.; Serova, A.; Voronin, N.

Monitoring of the spectral range which most affects solar-terrestrial relationship - soft X-ray and extreme UV-radiations allows to solve ? problem of solar activity influence on all aspects of the Sun - Earth ties and to select the most important precursors of solar flares and the solar events related with a flare (such as proton events, high-velocity plasma streams in the solar wind, shock waves, coronal mass ejection and, the most important, the beginning of principal magnetic storms). Solar activity is constantly monitored at present (in the USA) only in two sections of the spectrum of ionizing radiation: <0.8 nm and >115 (119) nm. However, so far there has been no monitoring of the flux in the most geoeffective region of the spectrum (0.8-115 nm) from the entire disk of the sun; this region completely monitors the main part of the ionosphere of the earth and the ionosphere of the other planets of the solar system, including the formation and status of the main ionospheric maxima. This occurs solely because of technical and methodological difficulties in performing the measurements and calibration in this spectral range on spacecraft, because it is necessity to use only windowless optics. At the present the solar the optical - electronic equipment (OEE) is testing and there are plans to launch OEE of Space Solar Patrol (SSP) consisting of solar radiometers and spectrometers at the Russian Module of the International Space Station. So the solving the problem of the permanent monitoring-patrol of ionizing radiation from the full disk of the Sun appears in the main tasks of fundamental scientific studies in space. The results of this monitoring can be contribution in development of simultaneous studies in several sciences, such as: - solar astrophysics (state of all solar atmospheric regions), - meteorology, physics of atmosphere (the influence of solar activity on global changes, climate and weather including the effects of atmo s pheric electricity), - aeronomy, astronautics (the influence of solar activity on density of upper atmo s phere and space craft slowing clown by it and characteristics of spacecraft outer atmo s phere), - radiophysics (determination and forecast ionospheric state of planets and radiowave transfer conditions), - heliobiology (the role of solar activity in biology and medical events), - seismology, possible sociology. There are the Resolutions with support of SSP Mission of the importance of this project from Commissions C, D and E of COSPAR, 1996, Commission G of URSI, 1996 and General Assembly of IAGA, 1999.

Thermal design of spacecraft solar arrays using a polyimide foam

NASA Astrophysics Data System (ADS)

Bianco, N.; Iasiello, M.; Naso, V.

2015-11-01

The design of the Thermal Control System (TCS) of spacecraft solar arrays plays a fundamental role. Indeed, the spacecraft components must operate within a certain range of temperature. If this doesn't occur, their performance is reduced and they may even break. Solar arrays, which are employed to recharge batteries, are directly exposed to the solar heat flux, and they need to be insulated from the earth's surface irradiation. Insulation is currently provided either with a white paint coating or with a Multi Layer Insulation (MLI) system [1]. A configuration based on an open-cell polyimide foam has also been recently proposed [2]. Using polyimide foams in TCSs looks very attractive in terms of costs, weight and assembling. An innovative thermal analysis of the above cited TCS configurations is carried out in this paper, by solving the porous media energy equation, under the assumption of Local Thermal Equilibrium (LTE) between the two phases. Radiation effects through the solar array are also considered by using the Rosseland approximation. Under a stationary daylight condition, temperature profiles are obtained by means of the finite-element based code COMSOL Multiphysics®. Finally, since the weight plays an important role in aerospace applications, weights of the three TCS configurations are compared.

Solar Demon: near real-time solar eruptive event detection on SDO/AIA images

NASA Astrophysics Data System (ADS)

Kraaikamp, Emil; Verbeeck, Cis

Solar flares, dimmings and EUV waves have been observed routinely in extreme ultra-violet (EUV) images of the Sun since 1996. These events are closely associated with coronal mass ejections (CMEs), and therefore provide useful information for early space weather alerts. The Solar Dynamics Observatory/Atmospheric Imaging Assembly (SDO/AIA) generates such a massive dataset that it becomes impossible to find most of these eruptive events manually. Solar Demon is a set of automatic detection algorithms that attempts to solve this problem by providing both near real-time warnings of eruptive events and a catalog of characterized events. Solar Demon has been designed to detect and characterize dimmings, EUV waves, as well as solar flares in near real-time on SDO/AIA data. The detection modules are running continuously at the Royal Observatory of Belgium on both quick-look data and synoptic science data. The output of Solar Demon can be accessed in near real-time on the Solar Demon website, and includes images, movies, light curves, and the numerical evolution of several parameters. Solar Demon is the result of collaboration between the FP7 projects AFFECTS and COMESEP. Flare detections of Solar Demon are integrated into the COMESEP alert system. Here we present the Solar Demon detection algorithms and their output. We will focus on the algorithm and its operational implementation. Examples of interesting flare, dimming and EUV wave events, and general statistics of the detections made so far during solar cycle 24 will be presented as well.

Models of the Solar Atmospheric Response to Flare Heating

NASA Technical Reports Server (NTRS)

Allred, Joel

2011-01-01

I will present models of the solar atmospheric response to flare heating. The models solve the equations of non-LTE radiation hydrodynamics with an electron beam added as a flare energy source term. Radiative transfer is solved in detail for many important optically thick hydrogen and helium transitions and numerous optically thin EUV lines making the models ideally suited to study the emission that is produced during flares. I will pay special attention to understanding key EUV lines as well the mechanism for white light production. I will also present preliminary results of how the model solar atmosphere responds to Fletcher & Hudson type flare heating. I will compare this with the results from flare simulations using the standard thick target model.

A new Caputo time fractional model for heat transfer enhancement of water based graphene nanofluid: An application to solar energy

NASA Astrophysics Data System (ADS)

Aman, Sidra; Khan, Ilyas; Ismail, Zulkhibri; Salleh, Mohd Zuki; Tlili, I.

2018-06-01

In this article the idea of Caputo time fractional derivatives is applied to MHD mixed convection Poiseuille flow of nanofluids with graphene nanoparticles in a vertical channel. The applications of nanofluids in solar energy are argued for various solar thermal systems. It is argued in the article that using nanofluids is an alternate source to produce solar energy in thermal engineering and solar energy devices in industries. The problem is modelled in terms of PDE's with initial and boundary conditions and solved analytically via Laplace transform method. The obtained solutions for velocity, temperature and concentration are expressed in terms of Wright's function. These solutions are significantly controlled by the variations of parameters including thermal Grashof number, Solutal Grashof number and nanoparticles volume fraction. Expressions for skin-friction, Nusselt and Sherwood numbers are also determined on left and right walls of the vertical channel with important numerical results in tabular form. It is found that rate of heat transfer increases with increasing nanoparticles volume fraction and Caputo time fractional parameters.

A simple orbit-attitude coupled modelling method for large solar power satellites

NASA Astrophysics Data System (ADS)

Li, Qingjun; Wang, Bo; Deng, Zichen; Ouyang, Huajiang; Wei, Yi

2018-04-01

A simple modelling method is proposed to study the orbit-attitude coupled dynamics of large solar power satellites based on natural coordinate formulation. The generalized coordinates are composed of Cartesian coordinates of two points and Cartesian components of two unitary vectors instead of Euler angles and angular velocities, which is the reason for its simplicity. Firstly, in order to develop natural coordinate formulation to take gravitational force and gravity gradient torque of a rigid body into account, Taylor series expansion is adopted to approximate the gravitational potential energy. The equations of motion are constructed through constrained Hamilton's equations. Then, an energy- and constraint-conserving algorithm is presented to solve the differential-algebraic equations. Finally, the proposed method is applied to simulate the orbit-attitude coupled dynamics and control of a large solar power satellite considering gravity gradient torque and solar radiation pressure. This method is also applicable to dynamic modelling of other rigid multibody aerospace systems.

Solar energy in buildings solved by building information modeling

NASA Astrophysics Data System (ADS)

Chudikova, B.; Faltejsek, M.

2018-03-01

Building lead us to use renewable energy sources for all types of buildings. The use of solar energy is the alternatives that can be applied in a good ratio of space, price, and resultant benefits. Building Information Modelling is a modern and effective way of dealing with buildings with regard to all aspects of the life cycle. The basis is careful planning and simulation in the pre-investment phase, where it is possible to determine the effective result and influence the lifetime of the building and the cost of its operation. By simulating, analysing and insert a building model into its future environment where climate conditions and surrounding buildings play a role, it is possible to predict the usability of the solar energy and establish an ideal model. Solar systems also very affect the internal layout of buildings. Pre-investment phase analysis, with a view to future aspects, will ensure that the resulting building will be both low-energy and environmentally friendly.

Heat-Energy Analysis for Solar Receivers

NASA Technical Reports Server (NTRS)

Lansing, F. L.

1982-01-01

Heat-energy analysis program (HEAP) solves general heat-transfer problems, with some specific features that are "custom made" for analyzing solar receivers. Can be utilized not only to predict receiver performance under varying solar flux, ambient temperature and local heat-transfer rates but also to detect locations of hotspots and metallurgical difficulties and to predict performance sensitivity of neighboring component parameters.

Dense-array concentrator photovoltaic system using non-imaging dish concentrator and crossed compound parabolic concentrator

NASA Astrophysics Data System (ADS)

Chong, Kok-Keong; Yew, Tiong-Keat; Wong, Chee-Woon; Tan, Ming-Hui; Tan, Woei-Chong; Lai, An-Chow; Lim, Boon-Han; Lau, Sing-Liong; Rahman, Faidz Abdul

2015-04-01

Solar concentrating device plays an important role by making use of optical technology in the design, which can be either reflector or lens to deliver high flux of sunlight onto the Concentrator Photovoltaic (CPV) module receiver ranging from hundreds to thousand suns. To be more competitive compared with fossil fuel, the current CPV systems using Fresnel lens and Parabolic dish as solar concentrator that are widely deployed in United States, Australia and Europe are facing great challenge to produce uniformly focused sunlight on the solar cells as to reduce the cost of electrical power generation. The concept of non-imaging optics is not new, but it has not fully explored by the researchers over the world especially in solving the problem of high concentration solar energy, which application is only limited to be a secondary focusing device or low concentration device using Compound Parabolic Concentrator. With the current advancement in the computer processing power, we has successfully invented the non-imaging dish concentrator (NIDC) using numerical simulation method to replace the current parabolic dish as primary focusing device with high solar concentration ratio (more than 400 suns) and large collective area (from 25 to 125 m2). In this paper, we disclose our research and development on dense array CPV system based on non-imaging optics. The geometry of the NIDC is determined using a special computational method. In addition, an array of secondary concentrators, namely crossed compound parabolic concentrators, is also proposed to further focus the concentrated sunlight by the NIDC onto active area of solar cells of the concentrator photovoltaic receiver. The invention maximizes the absorption of concentrated sunlight for the electric power generation system.

Solar wind and high energy particle effects in the middle atmosphere

NASA Technical Reports Server (NTRS)

Lastovicka, Jan

1989-01-01

The solar wind variability and high energy particle effects in the neutral middle atmosphere are not much known. These factors are important in the high latitude upper mesosphere, lower thermosphere energy budget. They influence temperature, composition (minor constituents of nitric oxide, ozone), circulation (wind system) and airflow. The vertical and latitudinal structures of such effects, mechanisms of downward penetration of energy and questions of energy abundance are largely to be solved. The most important recent finding seems to be the discovery of the role of highly relativistic electrons in the middle atmosphere at L = 3 - 8 (Baker et al., 1987). The solar wind and high energy particle flux variability appear to form a part of the chain of possible Sun-weather (climate) relationships. The importance of such studies in the nineties is emphasized by their role in big international programs STEP and IGBP - Global Change.

A 3D Multi-fluid MHD Study of the Interaction of the Solar Wind with the Ionosphere/Atmosphere System of Venus.

NASA Astrophysics Data System (ADS)

Najib, D.; Nagy, A.; Toth, G.; Ma, Y.-J.

2011-10-01

We use the latest version of our four species multifluid model to study the interaction of the solar wind with Venus. The model solves simultaneously the continuity, momentum and energy equations of the different ions. The lower boundary of our model is at 100 km, below the main ionospheric peak, and the radial resolution is about 10 km in the ionosphere, thus the model does a very good job in reproducing the ionosphere and the associated processes. We carry out calculations for high and low solar activity conditions and establish the importance of mass loading by the extended exosphere of Venus. We demonstrate the importance of using the multi-fluid rather than a single fluid model. We also calculate the atmospheric escape of the ionospheric species and compare our model results with the observed parameters from Pioneer Venus and Venus Express.

Numerical simulations of sheared magnetic lines at the solar null line

NASA Astrophysics Data System (ADS)

Kuźma, B.; Murawski, K.; Solov'ev, A.

2015-05-01

Aims: We perform numerical simulations of sheared magnetic lines at the magnetic null line configuration of two magnetic arcades that are settled in a gravitationally stratified and magnetically confined solar corona. Methods: We developed a general analytical model of a 2.5D solar atmospheric structure. As a particular application of this model, we adopted it for the curved magnetic field lines with an inverted Y shape that compose the null line above two magnetic arcades, which are embedded in the solar atmosphere that is specified by the realistic temperature distribution. The physical system is described by 2.5D magnetohydrodynamic equations that are numerically solved by the FLASH code. Results: The magnetic field line shearing, implemented about 200 km below the transition region, results in Alfvén and magnetoacoustic waves that are able to penetrate solar coronal regions above the magnetic null line. As a result of the coupling of these waves, partial reflection from the transition region and scattering from inhomogeneous regions the Alfvén waves experience fast attenuation on time scales comparable to their wave periods, and the physical system relaxes in time. The attenuation time grows with the large amplitude and characteristic growing time of the shearing. Conclusions: By having chosen a different magnetic flux function, the analytical model we devised can be adopted to derive equilibrium conditions for a diversity of 2.5D magnetic structures in the solar atmosphere. Movie associated to Fig. 5 is available in electronic form at http://www.aanda.org

Three-Dimensional, Ten-Moment, Two-Fluid Simulation of the Solar Wind Interaction with Mercury

NASA Astrophysics Data System (ADS)

Dong, C. F.; Wang, L.; Hakim, A.; Bhattacharjee, A.; Germaschewski, K.; DiBraccio, G. A.

2018-05-01

We investigate solar wind interaction with Mercury’s magnetosphere by using Gkeyll ten-moment multifluid code that solves the continuity, momentum, and pressure tensor equations of both protons and electrons, as well as the full Maxwell equations.

Time Dependent Models of Grain Formation Around Carbon Stars

NASA Technical Reports Server (NTRS)

Egan, M. P.; Shipman, R. F.

1996-01-01

Carbon-rich Asymptotic Giant Branch stars are sites of dust formation and undergo mass loss at rates ranging from 10(exp -7) to 10(exp -4) solar mass/yr. The state-of-the-art in modeling these processes is time-dependent models which simultaneously solve the grain formation and gas dynamics problem. We present results from such a model, which also includes an exact solution of the radiative transfer within the system.

Field-Lines-Threaded Model for: (1) the Low Solar Corona; (2) Electrons in the Transition Region; and (3) Solar Energetic Particle Acceleration and Transport

NASA Astrophysics Data System (ADS)

Sokolov, I.; van der Holst, B.; Jin, M.; Gombosi, T. I.; Taktakishvili, A.; Khazanov, G. V.

2013-12-01

In numerical simulations of the solar corona, both for the ambient state and especially for dynamical processes the most computational resources are spent for maintaining the numerical solution in the Low Solar Corona and in the transition region, where the temperature gradients are very sharp and the magnetic field has a complicated topology. The degraded computational efficiency is caused by the need in a highest resolution as well as the use of the fully three-dimensional implicit solver for electron heat conduction. On the other hand, the physical nature of the processes involved is rather simple (which still does not facilitate the numerical methods) as long as the heat fluxes as well as slow plasma motional velocities are aligned with the magnetic field. The Alfven wave turbulence, which is often believed to be the main driver of the solar wind and the main source of the coronal heating, is characterized by the Poynting flux of the waves, which is also aligned with the magnetic field. Therefore, the plasma state in any point of the three-dimensional grid in the Low Solar Corona can be found by solving a set of one-dimensional equations for the magnetic field line ('thread'), which passes through this point and connects it to the chromosphere and to the global Solar Corona. In the present paper we describe an innovative computational technology based upon the use of the magnetic-field-line-threads to find the local solution. We present the development of the AWSoM code of the University of Michigan with the field-lines-threaded Low Solar Corona. In the transition region, where the essentially kinetic description of the electron energy fluxes is required, we solve the Fokker-Plank equation on the system of threads, to achieve the physically consistent description of chromosphere evaporation. The third application for the field-lines-treaded model is the Solar Energetic Particle (SEP) acceleration and transport. Being the natural extension of the Field-Line-Advection Model for Particle Acceleration (FLAMPA), earlier suggested for a single magnetic field line advected with the plasma motion, the multiple-field-lines model allows us to simulate the SEP fluxes at multiple points of possible observation (at the Earth location, at STEREOs, at Mercury).

Five-Junction Solar Cell Optimization Using Silvaco Atlas

DTIC Science & Technology

2017-09-01

experimental sources [1], [4], [6]. f. Numerical Method The method selected for solving the non -linear equations that make up the simulation can be...and maximize efficiency. Optimization of solar cell efficiency is carried out via nearly orthogonal balanced design of experiments methodology . Silvaco...Optimization of solar cell efficiency is carried out via nearly orthogonal balanced design of experiments methodology . Silvaco ATLAS is utilized to

Influence of Axisymmetrically Deformed Explosions in Type II Supernovae on the Reproduction of the Solar System Abundances

NASA Astrophysics Data System (ADS)

Nagataki, Shigehiro

1999-01-01

We have tried to reproduce the solar system abundances using the nucleosynthesis products of Type Ia and Type II supernovae. In particular, we examined the effects of axisymmetrically deformed explosions in Type II supernovae. 44Ca and 47,48Ti are enhanced considerably in axisymmetrically deformed explosion models because of the active alpha-rich freezeout. The enhancement of nuclei around A=45 is a welcome result since it solves the problem of the nuclei shortage. Moreover, 59Co, 63,65Cu, and 66Zn are enhanced enough to reproduce the solar system abundances. The enhancement of Cu and Zn means the possibility that these nuclei, which have been said to be produced by the slow process, can be synthesized fairly well during the explosive nucleosynthesis. To discuss their origin quantitatively, the position of the mass cut is a very important parameter that is very difficult to determine numerically at present. We also stress that an axisymmetrically deformed explosion of Type II supernovae of the degree that is considered in this analysis is not excluded by the results of calculations of explosive nucleosynthesis, that is, the nucleosynthesis products are not extremely disturbed and the solar system abundances can be reproduced fairly well by the axisymmetrically deformed explosion models. This conclusion will be good for the theory of core collapse including the rotation of an iron core, magnetic field, and axisymmetrically modified neutrino radiation from a rotating protoneutron star, which possibly can cause an axisymmetrically deformed explosion.

Multiscale computational modeling of a radiantly driven solar thermal collector

NASA Astrophysics Data System (ADS)

Ponnuru, Koushik

The objectives of the master's thesis are to present, discuss and apply sequential multiscale modeling that combines analytical, numerical (finite element-based) and computational fluid dynamic (CFD) analysis to assist in the development of a radiantly driven macroscale solar thermal collector for energy harvesting. The solar thermal collector is a novel green energy system that converts solar energy to heat and utilizes dry air as a working heat transfer fluid (HTF). This energy system has important advantages over competitive technologies: it is self-contained (no energy sources are needed), there are no moving parts, no oil or supplementary fluids are needed and it is environmentally friendly since it is powered by solar radiation. This work focuses on the development of multi-physics and multiscale models for predicting the performance of the solar thermal collector. Model construction and validation is organized around three distinct and complementary levels. The first level involves an analytical analysis of the thermal transpiration phenomenon and models for predicting the associated mass flow pumping that occurs in an aerogel membrane in the presence of a large thermal gradient. Within the aerogel, a combination of convection, conduction and radiation occurs simultaneously in a domain where the pore size is comparable to the mean free path of the gas molecules. CFD modeling of thermal transpiration is not possible because all the available commercial CFD codes solve the Navier Stokes equations only for continuum flow, which is based on the assumption that the net molecular mass diffusion is zero. However, thermal transpiration occurs in a flow regime where a non-zero net molecular mass diffusion exists. Thus these effects are modeled by using Sharipov's [2] analytical expression for gas flow characterized by high Knudsen number. The second level uses a detailed CFD model solving Navier Stokes equations for momentum, heat and mass transfer in the various components of the device. We have used state-of-the-art computational fluid dynamics (CFD) software, Flow3D (www.flow3d.com) to model the effects of multiple coupled physical processes including buoyancy driven flow from local temperature differences within the plenums, fluid-solid momentum and heat transfer, and coupled radiation exchange between the aerogel, top glazing and environment. In addition, the CFD models include both convection and radiation exchange between the top glazing and the environment. Transient and steady-state thermal models have been constructed using COMSOL Multiphysics. The third level consists of a lumped-element system model, which enables rapid parametric analysis and helps to develop an understanding of the system behavior; the mathematical models developed and multiple CFD simulations studies focus on simultaneous solution of heat, momentum, mass and gas volume fraction balances and succeed in accurate state variable distributions confirmed by experimental measurements.

Development of an energy storage tank model

NASA Astrophysics Data System (ADS)

Buckley, Robert Christopher

A linearized, one-dimensional finite difference model employing an implicit finite difference method for energy storage tanks is developed, programmed with MATLAB, and demonstrated for different applications. A set of nodal energy equations is developed by considering the energy interactions on a small control volume. The general method of solving these equations is described as are other features of the simulation program. Two modeling applications are presented: the first using a hot water storage tank with a solar collector and an absorption chiller to cool a building in the summer, the second using a molten salt storage system with a solar collector and steam power plant to generate electricity. Recommendations for further study as well as all of the source code generated in the project are also provided.

Optimal low-thrust trajectories for nuclear and solar electric propulsion

NASA Astrophysics Data System (ADS)

Genta, G.; Maffione, P. F.

2016-01-01

The optimization of the trajectory and of the thrust profile of a low-thrust interplanetary transfer is usually solved under the assumption that the specific mass of the power generator is constant. While this is reasonable in the case of nuclear electric propulsion, if solar electric propulsion is used the specific mass depends on the distance of the spacecraft from the Sun. In the present paper the optimization of the trajectory of the spacecraft and of the thrust profile is solved under the latter assumption, to obtain optimized interplanetary trajectories for solar electric spacecraft, also taking into account all phases of the journey, from low orbit about the starting planet to low orbit about the destination one. General plots linking together the travel time, the specific mass of the generator and the propellant consumption are obtained.

AVERAGE ANNUAL SOLAR UV DOSE OF THE CONTINENTAL US CITIZEN

EPA Science Inventory

The average annual solar UV dose of US citizens is not known, but is required for relative risk assessments of skin cancer from UV-emitting devices. We solved this problem using a novel approach. The EPA's "National Human Activity Pattern Survey" recorded the daily ou...

Propellantless Attitude Control of Solar Sail Technology Utilizing Reflective Control Devices

NASA Technical Reports Server (NTRS)

Munday, Jeremy

2016-01-01

Solar sails offer an opportunity for a CubeSatscale, propellant-free spacecraft technology that enables long-term and long-distance missions not possible with traditional methods. Solar sails operate using the transfer of linear momentum from photons of sunlight reflected from the surface of the sail. To propel the spacecraft, no mechanically moving parts, thrusters, or propellant are needed. However, attitude control, or orientation, is still performed using traditional methods involving reaction wheels and propellant ejection, which severely limit mission lifetime. For example, the current state of the art solutions employed by upcoming missions couple solar sails with a state of the art propellant ejection gas system. Here, the use of the gas thruster has limited the lifetime of the mission. To solve the limited mission lifetime problem, the Propellantless Attitude Control of Solar Sail Technology Utilizing Reflective Control Devices project team is working on propellantless attitude control using thin layers of material, an optical film, electrically switchable from transparent to reflective. The technology is based on a polymer-dispersed liquid crystal (PDLC), which allows this switch upon application of a voltage. This technology removes the need for propellant, which reduces weight and cost while improving performance and lifetime.

Homoclinic orbits in three-dimensional Shilnikov-type chaotic systems

NASA Astrophysics Data System (ADS)

Feng, Jing-Jing; Zhang, Qi-Chang; Wang, Wei; Hao, Shu-Ying

2013-09-01

In this paper, the Padé approximant and analytic solution in the neighborhood of the initial value are introduced into the process of constructing the Shilnikov type homoclinic trajectories in three-dimensional nonlinear dynamical systems. The PID controller system with quadratic and cubic nonlinearities, the simplified solar-wind-driven-magnetosphere-ionosphere system, and the human DNA sequence system are considered. With the aid of presenting a new condition, the solutions of solving the boundary-value problems which are formulated for the trajectory and evaluating the initial amplitude values become available. At the same time, the value of the bifurcation parameter is obtained directly, which is almost consistent with the numerical result.

Mathematical Modeling and Numerical Analysis of Thermal Distribution in Arch Dams considering Solar Radiation Effect

PubMed Central

Mirzabozorg, H.; Hariri-Ardebili, M. A.; Shirkhan, M.; Seyed-Kolbadi, S. M.

2014-01-01

The effect of solar radiation on thermal distribution in thin high arch dams is investigated. The differential equation governing thermal behavior of mass concrete in three-dimensional space is solved applying appropriate boundary conditions. Solar radiation is implemented considering the dam face direction relative to the sun, the slop relative to horizon, the region cloud cover, and the surrounding topography. It has been observed that solar radiation changes the surface temperature drastically and leads to nonuniform temperature distribution. Solar radiation effects should be considered in thermal transient analysis of thin arch dams. PMID:24695817

Mathematical modeling and numerical analysis of thermal distribution in arch dams considering solar radiation effect.

PubMed

Mirzabozorg, H; Hariri-Ardebili, M A; Shirkhan, M; Seyed-Kolbadi, S M

2014-01-01

The effect of solar radiation on thermal distribution in thin high arch dams is investigated. The differential equation governing thermal behavior of mass concrete in three-dimensional space is solved applying appropriate boundary conditions. Solar radiation is implemented considering the dam face direction relative to the sun, the slop relative to horizon, the region cloud cover, and the surrounding topography. It has been observed that solar radiation changes the surface temperature drastically and leads to nonuniform temperature distribution. Solar radiation effects should be considered in thermal transient analysis of thin arch dams.

A numerical calculation of outward propagation of solar disturbances. [solar atmospheric model with shock wave propagation

NASA Technical Reports Server (NTRS)

Wu, S. T.

1974-01-01

The responses of the solar atmosphere due to an outward propagation shock are examined by employing the Lax-Wendroff method to solve the set of nonlinear partial differential equations in the model of the solar atmosphere. It is found that this theoretical model can be used to explain the solar phenomena of surge and spray. A criterion to discriminate the surge and spray is established and detailed information concerning the density, velocity, and temperature distribution with respect to the height and time is presented. The complete computer program is also included.

Design of Solar Heat Sheet for Air Heaters

NASA Astrophysics Data System (ADS)

Priya, S. Shanmuga; Premalatha, M.; Thirunavukkarasu, I.

2011-12-01

The technique of harnessing solar energy for drying offers significant potential to dry agricultural products such as food grains, fruits, vegetables and medicinal plants, thereby eliminating many of the problems experienced with open-sun drying and industrial drying, besides saving huge quantities of fossil fuels. A great deal of experimental work over the last few decades has already demonstrated that agricultural products can be satisfactorily dehydrated using solar energy. Various designs of small scale solar dryers have been developed in the recent past, mainly for drying agricultural products. Major problems experienced with solar dryers are their non-reliability as their operation largely depends on local weather conditions. While back-up heaters and hybrid dryers partly solved this issue, difficulties in controlling the drying air temperature and flow rate remains a problem, and affects the quality of the dried product. This study is aimed at eliminating the fluctuations in the quality of hot air supplied by simple solar air heaters used for drying fruits, vegetables and other applications. It is an attempt to analyse the applicability of the combination of an glazed transpired solar collector (tank), thermal storage and a intake fan(suction fan) to achieve a steady supply of air at a different atmospheric temperature and flow rate for drying fruits and vegetables. Development of an efficient, low-cost and reliable air heating system for drying applications is done.

Coupled optical and thermal detailed simulations for the accurate evaluation and performance improvement of molten salts solar towers

NASA Astrophysics Data System (ADS)

García-Barberena, Javier; Mutuberria, Amaia; Palacin, Luis G.; Sanz, Javier L.; Pereira, Daniel; Bernardos, Ana; Sanchez, Marcelino; Rocha, Alberto R.

2017-06-01

The National Renewable Energy Centre of Spain, CENER, and the Technology & Innovation area of ACS Cobra, as a result of their long term expertise in the CSP field, have developed a high-quality and high level of detail optical and thermal simulation software for the accurate evaluation of Molten Salts Solar Towers. The main purpose of this software is to make a step forward in the state-of-the-art of the Solar Towers simulation programs. Generally, these programs deal with the most critical systems of such plants, i.e. the solar field and the receiver, on an independent basis. Therefore, these programs typically neglect relevant aspects in the operation of the plant as heliostat aiming strategies, solar flux shapes onto the receiver, material physical and operational limitations, transient processes as preheating and secure cloud passing operating modes, and more. The modelling approach implemented in the developed program consists on effectively coupling detailed optical simulations of the heliostat field with also detailed and full-transient thermal simulations of the molten salts tube-based external receiver. The optical model is based on an accurate Monte Carlo ray-tracing method which solves the complete solar field by simulating each of the heliostats at once according to their specific layout in the field. In the thermal side, the tube-based cylindrical external receiver of a Molten Salts Solar Tower is modelled assuming one representative tube per panel, and implementing the specific connection layout of the panels as well as the internal receiver pipes. Each tube is longitudinally discretized and the transient energy and mass balances in the temperature dependent molten salts and steel tube models are solved. For this, a one dimensional radial heat transfer model based is used. The thermal model is completed with a detailed control and operation strategy module, able to represent the appropriate operation of the plant. An integration framework has been developed, helping ACS Cobra to adequately handle the optical and thermal coupled simulations. According to current results it can be concluded that the developed model has resulted in a powerful tool to improve the design and operation of future ACS Cobra's Molten Salts Solar Towers, since historical data based on its projects have been used for validation of the final tool.

Performance Analysis of Solar-Wind-Diesel-Battery Hybrid Energy System for KLIA Sepang Station of Malaysia

NASA Astrophysics Data System (ADS)

Shezan, S. K. A.; Saidur, R.; Hossain, A.; Chong, W. T.; Kibria, M. A.

2015-09-01

A large number of populations of the world live in rural or remote areas those are geographically isolated. Power supply and uninterrupted fuel transportation to produce electrical power for these remote areas poses a great challenge. Using renewable energy in hybrid energy system might be a pathway to solve this problem. Malaysia is a large hilly land with the gift of renewable energy resources. There is a good chance to utilize these renewable resources to produce electrical power and to limit the dependency on the fossil fuel as well as reduce the carbon emissions. In this perspective, a research is carried out to analyze the performance of a solar-wind-diesel-battery hybrid energy system for a remote area named “KLIA Sepang station” in the state of Selangor, Malaysia. In this study, a 56 kW hybrid energy system has been proposed that is capable to support more than 50 households and 6 shops in that area. Real time field data of solar radiation and wind speed is used for the simulation and optimization of operations using “Homer” renewable energy software. The proposed system can reduce CO2 emission by about 16 tons per year compared to diesel generator only. In the same time the Cost of energy (COE) of the optimized system is USD 5.126/kWh.The proposed hybrid energy system might be applicable for other parts of the world where the climate conditions are similar.

A kinetic approach to magnetospheric modeling

NASA Technical Reports Server (NTRS)

Whipple, E. C., Jr.

1979-01-01

The earth's magnetosphere is caused by the interaction between the flowing solar wind and the earth's magnetic dipole, with the distorted magnetic field in the outer parts of the magnetosphere due to the current systems resulting from this interaction. It is surprising that even the conceptually simple problem of the collisionless interaction of a flowing plasma with a dipole magnetic field has not been solved. A kinetic approach is essential if one is to take into account the dispersion of particles with different energies and pitch angles and the fact that particles on different trajectories have different histories and may come from different sources. Solving the interaction problem involves finding the various types of possible trajectories, populating them with particles appropriately, and then treating the electric and magnetic fields self-consistently with the resulting particle densities and currents. This approach is illustrated by formulating a procedure for solving the collisionless interaction problem on open field lines in the case of a slowly flowing magnetized plasma interacting with a magnetic dipole.

Problem Solving in Practice

ERIC Educational Resources Information Center

Greene, Kim; Heyck-Williams, Jeff; Timpson Gray, Elicia

2017-01-01

Problem solving spans all grade levels and content areas, as evidenced by this compilation of projects from schools across the United States. In one project, high school girls built a solar-powered tent to serve their city's homeless population. In another project, 4th graders explored historic Jamestown to learn about the voices lost to history.…

Performance Analysis and Optimization of Concentrating Solar Thermoelectric Generator

NASA Astrophysics Data System (ADS)

Lamba, Ravita; Manikandan, S.; Kaushik, S. C.

2018-06-01

A thermodynamic model for a concentrating solar thermoelectric generator considering the Thomson effect combined with Fourier heat conduction, Peltier, and Joule heating has been developed and optimized in MATLAB environment. The temperatures at the hot and cold junctions of the thermoelectric generator were evaluated by solving the energy balance equations at both junctions. The effects of the solar concentration ratio, input electrical current, number of thermocouples, and electrical load resistance ratio on the power output and energy and exergy efficiencies of the system were studied. Optimization studies were carried out for the STEG system, and the optimum number of thermocouples, concentration ratio, and resistance ratio determined. The results showed that the optimum values of these parameters are different for conditions of maximum power output and maximum energy and exergy efficiency. The optimum values of the concentration ratio and load resistance ratio for maximum energy efficiency of 5.85% and maximum exergy efficiency of 6.29% were found to be 180 and 1.3, respectively, with corresponding power output of 4.213 W. Furthermore, at higher concentration ratio (C = 600), the optimum number of thermocouples was found to be 101 for maximum power output of 13.75 W, maximum energy efficiency of 5.73%, and maximum exergy efficiency of 6.16%. Moreover, the optimum number of thermocouple was the same for conditions of maximum power output and energy and exergy efficiency. The results of this study may provide insight for design of actual concentrated solar thermoelectric generator systems.

Update on the Solar Power Satellite transmitter design

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

Brown, W.C.

1986-01-01

A number of remaining problems in the conceptual design of the transmitting antenna for the Solar Power Satellite have been solved as a result of additional technology development. Much of the technology was derived from the conceptual design of a ground-based transmitting antenna for beaming power to a high altitude airship or airplane.

A three-dimensional model of corotating streams in the solar wind. 1: Theoretical foundations

NASA Technical Reports Server (NTRS)

Pizzo, V. J.

1978-01-01

The theoretical and mathematical background pertinent to the study of steady, corotating solar wind structure in all three spatial dimensions (3-D) is discussed. The dynamical evolution of the plasma in interplanetary space (defined as the region beyond roughly 35 solar radii where the flow is supersonic) is approximately described by the nonlinear, single fluid, polytropic (magneto-) hydrodynamic equations. Efficient numerical techniques for solving this complex system of coupled, hyperbolic partial differential equations are outlined. The formulation is inviscid and nonmagnetic, but methods allow for the potential inclusion of both features with only modest modifications. One simple, highly idealized, hydrodynamic model stream is examined to illustrate the fundamental processes involved in the 3-D dynamics of stream evolution. Spatial variations in the rotational stream interaction mechanism were found to produce small nonradial flows on a global scale that lead to the transport of mass, energy, and momentum away from regions of relative compression and into regions of relative rarefaction.

The solar power satellite - A programme for development aid

NASA Astrophysics Data System (ADS)

Meiner, R. C.

It is pointed out that there are essentially four types of foreign aid. These types include the transfer of knowledge, the transfer of materials, the transfer of funds, and the provision of preferential agreements. A great number of studies have been conducted to assess the pros and cons of a Solar Power Satellite System (SPSS). According to many, the most difficult problems which have to be solved in connection with such a project are related to environmental, societal, political, and institutional aspects. The present investigation is concerned with the initiation of a gradual, phased approach toward a Solar Power Satellite (SPS). Phase I of such an approach would involve the set-up of an organization and the allocation of studies. The building of photovoltaic farms and of an SPS pilot project would occur during the second phase, while development and deployment of a full SPSS would take place during the third phase. The developments are to be financed under foreign aid.

Mechanics analysis of the multi-point-load process for the thin film solar cell

NASA Astrophysics Data System (ADS)

Wang, Zhiming; Wei, Guangpu; Gong, Zhengbang

2008-02-01

The main element of thin film solar cell is silicon. Because of the special mechanical characteristic of silicon, the method of loading pressure on the thin film solar cell and the value of pressure is the key problem which must be solved during the manufacturing of thin film solar cell. This paper describes the special mechanical characteristic of silicon, discussed the test method overall; value of pressure on thin film solar cell; the elements and the method of load by ANSYS finite element, according to these theory analysis, we obtained the key conclusion in the actual operation, these result have a great meaning in industry.

Coupling of the coronal helium abundance to the solar wind

NASA Technical Reports Server (NTRS)

Hansteen, Viggo H.; Leer, Egil; Holzer, Thomas E.

1994-01-01

Models of the transition region-corona-solar wind system are investigated in order to find the coronal helium abundance and to study the role played by coronal helium in controlling the solar wind proton flux. The thermal force on alpha-particles in the transition region sets the flow of helium into the corona. The frictional coupling between alpha-particles and protons and/or the electric polarization field determines the proton flux in the solar wind as well as the fate of the coronal helium content. The models are constructed by solving the time-dependent population and momentum equations for all species of hydrogen and helium in an atmosphere with a given temperature profile. Several temperature profiles are considered in order to very the roles of frictional coupling and electric polarization field in the solar wind, and the thermal force in the transition region. Steady-state solutions are found for coronae with a hydrogen flux at 1 AU of 1.0 x 10(exp 9)/cm(exp 2)/sec or larger. For coronae with lower hydrogen fluxes, the helium flux into the corona is larger than the flux 'pulled out' by the solar wind protons, and solutions with increasing coronal helium content are found. The timescale for forming a helium-filled corona, that may allow for a steady outflow, is long compared to the mixing time for the corona.

The Hybrid Propellant Module (HPM): A New Concept for Space Transfer in the Earth's Neighborhood and Beyond

NASA Technical Reports Server (NTRS)

Mankins, John C.; Mazanek, Daniel D.

2001-01-01

The safe, affordable and effective transfer of ever-larger payloads and eventually personnel beyond Low Earth Orbit (LEO) is a major challenge facing future commercial development and human exploration of space. Without reusable systems, sustained exploration or large scale development beyond LEO appears to be economically non-viable. However, reusable systems must be capable of both good fuel efficiency and "high utilization of capacity", or else economic costs will remain unacceptably high. Various options exist that can provide high fuel efficiency - for example, Solar Electric Propulsion Systems (SEPS) - but only at the cost of low thrust and concomitant long transit times. Chemical propulsion systems offer the potential for high thrust and short transit times - including both cryogenic and non-cryogenic options - but only at the cost of relatively low specific impulse (Isp). Nuclear thermal propulsion systems offer relatively good thrust-to-weight and Isp - but involve public concerns that may be insurmountable for all except the most-critical of public purposes. Fixed infrastructures have been suggested as one approach to solving this challenge; for example, rotating tether approaches. However, these systems tend to suffer from high initial costs or unacceptable operational constraints. A new concept has been identified - the Hybrid Propellant Module (HPM) - that integrates the best features of both chemical and solar electric transportation architectures. The HPM approach appears to hold promise of solving the issues associated with other approaches, opening a new family of capabilities for future space exploration and development of near-Earth space and beyond. This paper provides a summary overview of the challenge of Earth neighborhood transportation and discusses how various systems concepts might be applied to meet the needs of these architectures. The paper describes a new approach, the HPM, and illustrates the application of the concept for a typical mission concept. The paper concludes with a discussion of needed technologies and a possible timeline for the development and evolution of this class of systems concepts.

Science with the solar optical telescope

NASA Technical Reports Server (NTRS)

Jordan, S. D.; Hogan, G. D.

1984-01-01

The Solar Optical Telescope (SOT) is designed to provide the solar physics community with the data necessary for solving several fundamental problems in the energetics and dynamics of the solar atmosphere. Among these problems are questions on the origin and evolution of the sun's magnetic field, heating of the outer solar atmosphere, and sources of the solar wind in the lower lying regions of the outer atmosphere. The SOT will be built under the management of NASA's Goddard Space Flight Center, with science instruments provided by teams led by Principal Investigators. The telescope will be built by the Perkin-Elmer Corporation, and the science instruments selected for the first flight will be provided by the Lockheed Palo Alto Research Laboratory (LPARL) and the California Institute of Technology, with actual construction of a combined science instrument taking place at the LPARL. The SOT has a 1.3-meter-diameter primary mirror that will be capable of achieving diffraction-limited viewing in the visible of 0.1 arc-second. This dimension is less than a hydrodynamic scale-height or a mean-free-path of a continuum photon in the solar atmosphere. Image stability will be achieved by a control system in the telescope, which moves both the primary and tertiary mirrors in tandem, and will be further enhanced by a correlation tracker in the combined science instrument. The SOT Facility is currently scheduled for its first flight on Spacelab at the beginning of the 1990's.

Advanced design for orbital debris removal in support of solar system exploration

NASA Technical Reports Server (NTRS)

1991-01-01

The development of an Autonomous Space Processor for Orbital Debris (ASPOD) is the ultimate goal. The craft will process, in situ, orbital debris using resources available in low Earth orbit (LEO). The serious problem of orbital debris is briefly described and the nature of the large debris population is outlined. This year, focus was on development of a versatile robotic manipulator to augment an existing robotic arm; incorporation of remote operation of robotic arms; and formulation of optimal (time and energy) trajectory planning algorithms for coordinating robotic arms. The mechanical design of the new arm is described in detail. The versatile work envelope is explained showing the flexibility of the new design. Several telemetry communication systems are described which will enable the remote operation of the robotic arms. The trajectory planning algorithms are fully developed for both the time-optimal and energy-optimal problem. The optimal problem is solved using phase plane techniques while the energy optimal problem is solved using dynamics programming.

Complexity of the Earth's space-atmosphere interaction region (SAIR) response to the solar flux at 10.7 cm as seen through the evaluation of five solar cycle two-line element (TLE) records

NASA Astrophysics Data System (ADS)

Molaverdikhani, Karan; Ajabshirizadeh, Ali; Davoudifar, Pantea; Lashkanpour, Majid

2016-09-01

Orbital debris are long-standing threats to space systems. They also contribute to the flux of macroscopic particles into the Earth's atmosphere and eventually affects environmental processes across several other related regions. As impactful space debris may be, debris along with other Low Earth Orbit (LEO) orbiting objects, also serve as valuable long-monitoring probes to deduce the properties of geospace environment in-situ. We define the Daily Decay Rate (DDR) as a suitable indicator of how the Earth's space-atmosphere interaction region (SAIR) responds to solar activity and how solar activity directly affects the orbital evolution of a LEO orbiter. We present a computationally simplified technique that simultaneously solves the motion equations for DDR and cross-sectional area to mass ratio (A/m) from consecutive TLE records. By evaluating more than 50 million TLE records we estimate A/m of 15,307 NORAD-indexed objects and determine how DDR varies. We observe the thermospheric ;natural thermostat; in our results, consistent with previous studies. We compare the observed DDRs with two models based on NRLMSISE-00 and DTM-2013, and present evidence the models display a systemic altitudinal bias. We propose several possibilities to explain this altitudinal bias including the overestimated CD at low altitudes in our models (presumably due to the despinning effect of perturbing forces on the orbiting objects), and incomplete and limited coverage of in-situ observations at high solar activity. We conclude that the density models do not reliably reproduce the densities and atmospheric-thermospheric behaviors at high solar active conditions, especially for F10.7 cm above 300 sfu.

Prediction of the solar modulation of galactic cosmic rays and radiation dose of aircrews up to the solar cycle 26

NASA Astrophysics Data System (ADS)

Miyake, S.; Kataoka, R.; Sato, T.

2016-12-01

The solar modulation of galactic cosmic rays (GCRs), which is the variation of the terrestrial GCR flux caused by the heliospheric environmental change, is basically anti-correlated with the solar activity with so-called 11-year periodicity. In the current weak solar cycle 24, we expect that the flux of GCRs is getting higher than that in the previous solar cycles, leading to the increase in the radiation exposure in the space and atmosphere. In order to quantitatively evaluate the possible solar modulation of GCRs and resultant radiation exposure at flight altitude during the solar cycles 24, 25, and 26, we have developed the time-dependent and three-dimensional model of the solar modulation of GCRs. Our model can give the flux of GCRs anywhere in the heliosphere by assuming the variation of the solar wind velocity, the strength of the interplanetary magnetic field, and its tilt angle. We solve the curvature and gradient drift motion of GCRs in the heliospheric magnetic field, and therefore reproduce the 22-year variation of the solar modulation of GCRs. It is quantitatively confirmed that our model reproduces the energy spectra observed by BESS and PAMELA. We then calculate the variation of the GCR energy spectra during the solar cycles 24, 25, and 26, by extrapolating the solar wind parameters and tilt angle. We also calculate the neutron monitor counting rate and the radiation dose of aircrews at flight altitude, by the air-shower simulation performed by PHITS (Particle and Heavy Ion Transport code System). In this presentation, we report the quantitative forecast values of the solar modulation of GCRs, neutron monitor counting rate, and the radiation dose at flight altitude up to the cycle 26, including the discussion of the charge sign dependence on those results.

Sustainer electric propulsion system application for spacecraft attitude control

NASA Astrophysics Data System (ADS)

Obukhov, V. A.; Pokryshkin, A. I.; Popov, G. A.; Yashina, N. V.

2010-07-01

Application of electric propulsion system (EPS) requires spacecraft (SC) equipping with large solar panels (SP) for the power supply to electric propulsions. This makes the problem of EPS-equipped SC control at the insertion stage more difficult to solve than in the case of SC equipped with chemical engines, because in addition to the SC attitude control associated with the mission there appears necessity in keeping SP orientation to Sun that is necessary for generation of electric power sufficient for the operation of service systems, purpose-oriented equipment, and EPS. The theoretical study of the control problem is the most interesting for a non-coplanar transfer from high elliptic orbit (HEO) to geostationary orbit (GSO).

Heterostructure solar cells

NASA Technical Reports Server (NTRS)

Chang, K. I.; Yeh, Y. C. M.; Iles, P. A.; Morris, R. K.

1987-01-01

The performance of gallium arsenide solar cells grown on Ge substrates is discussed. In some cases the substrate was thinned to reduce overall cell weight with good ruggedness. The conversion efficiency of 2 by 2 cm cells under AMO reached 17.1 percent with a cell thickness of 6 mils. The work described forms the basis for future cascade cell structures, where similar interconnecting problems between the top cell and the bottom cell must be solved. Applications of the GaAs/Ge solar cell in space and the expected payoffs are discussed.

NASA Tech Briefs, June 2007

NASA Technical Reports Server (NTRS)

2007-01-01

Topics covered include: High-Accuracy, High-Dynamic-Range Phase-Measurement System; Simple, Compact, Safe Impact Tester; Multi-Antenna Radar Systems for Doppler Rain Measurements; 600-GHz Electronically Tunable Vector Measurement System; Modular Architecture for the Measurement of Space Radiation; VLSI Design of a Turbo Decoder; Architecture of an Autonomous Radio Receiver; Improved On-Chip Measurement of Delay in an FPGA or ASIC; Resource Selection and Ranking; Accident/Mishap Investigation System; Simplified Identification of mRNA or DNA in Whole Cells; Printed Multi-Turn Loop Antennas for RF Biotelemetry; Making Ternary Quantum Dots From Single-Source Precursors; Improved Single-Source Precursors for Solar-Cell Absorbers; Spray CVD for Making Solar-Cell Absorber Layers; Glass/BNNT Composite for Sealing Solid Oxide Fuel Cells; A Method of Assembling Compact Coherent Fiber-Optic Bundles; Manufacturing Diamond Under Very High Pressure; Ring-Resonator/Sol-Gel Interferometric Immunosensor; Compact Fuel-Cell System Would Consume Neat Methanol; Algorithm Would Enable Robots to Solve Problems Creatively; Hypothetical Scenario Generator for Fault-Tolerant Diagnosis; Smart Data Node in the Sky; Pseudo-Waypoint Guidance for Proximity Spacecraft Maneuvers; Update on Controlling Herds of Cooperative Robots; and Simulation and Testing of Maneuvering of a Planetary Rover.

Restoration of solar and star images with phase diversity-based blind deconvolution

NASA Astrophysics Data System (ADS)

Li, Qiang; Liao, Sheng; Wei, Honggang; Shen, Mangzuo

2007-04-01

The images recorded by a ground-based telescope are often degraded by atmospheric turbulence and the aberration of the optical system. Phase diversity-based blind deconvolution is an effective post-processing method that can be used to overcome the turbulence-induced degradation. The method uses an ensemble of short-exposure images obtained simultaneously from multiple cameras to jointly estimate the object and the wavefront distribution on pupil. Based on signal estimation theory and optimization theory, we derive the cost function and solve the large-scale optimization problem using a limited memory Broyden-Fletcher-Goldfarb-Shanno (L-BFGS) method. We apply the method to the turbulence-degraded images generated with computer, the solar images acquired with the swedish vacuum solar telescope (SVST, 0.475 m) in La Palma and the star images collected with 1.2-m telescope in Yunnan Observatory. In order to avoid edge effect in the restoration of the solar images, a modified Hanning apodized window is adopted. The star image still can be restored when the defocus distance is measured inaccurately. The restored results demonstrate that the method is efficient for removing the effect of turbulence and reconstructing the point-like or extended objects.

High-temperature thermal storage systems for advanced solar receivers materials selections

NASA Astrophysics Data System (ADS)

Wilson, D. F.; Devan, J. H.; Howell, M.

1990-09-01

Advanced space power systems that use solar energy and Brayton or Stirling heat engines require thermal energy storage (TES) systems to operate continuously through periods of shade. The receiver storage units, key elements in both Brayton and Stirling systems, are designed to use the latent heat of fusion of phase-change materials (PCMs). The power systems under current consideration for near-future National Aeronautics and Space Administration space missions require working fluid temperatures in the 1100 to 1400 K range. The PCMs under current investigation that gave liquid temperatures within this range are the fluoride family of salts. However, these salts have low thermal conductivity, which causes large temperature gradients in the storage systems. Improvements can be obtained, however, with the use of thermal conductivity enhancements or metallic PCMs. In fact, if suitable containment materials can be found, the use of metallic PCMs would virtually eliminate the orbit associated temperature variations in TES systems. The high thermal conductivity and generally low volume change on melting of germanium and alloys based on silicon make them attractive for storage of thermal energy in space power systems. An approach to solving the containment problem, involving both chemical and physical compatibility, preparation of NiSi/NiSi2, and initial results for containment of germanium and NiSi/NiSi2, are presented.

High-temperature thermal storage systems for advanced solar receivers materials selections

NASA Technical Reports Server (NTRS)

Wilson, D. F.; Devan, J. H.; Howell, M.

1990-01-01

Advanced space power systems that use solar energy and Brayton or Stirling heat engines require thermal energy storage (TES) systems to operate continuously through periods of shade. The receiver storage units, key elements in both Brayton and Stirling systems, are designed to use the latent heat of fusion of phase-change materials (PCMs). The power systems under current consideration for near-future National Aeronautics and Space Administration space missions require working fluid temperatures in the 1100 to 1400 K range. The PCMs under current investigation that gave liquid temperatures within this range are the fluoride family of salts. However, these salts have low thermal conductivity, which causes large temperature gradients in the storage systems. Improvements can be obtained, however, with the use of thermal conductivity enhancements or metallic PCMs. In fact, if suitable containment materials can be found, the use of metallic PCMs would virtually eliminate the orbit associated temperature variations in TES systems. The high thermal conductivity and generally low volume change on melting of germanium and alloys based on silicon make them attractive for storage of thermal energy in space power systems. An approach to solving the containment problem, involving both chemical and physical compatibility, preparation of NiSi/NiSi2, and initial results for containment of germanium and NiSi/NiSi2, are presented.

Small photovoltaic setup for the air conditioning system

NASA Astrophysics Data System (ADS)

Masiukiewicz, Maciej

2017-10-01

The increasing interest in air conditioning systems for residential applications in Poland will certainly increase the demand for electricity during the summer period. Due to this fact a growing interest in solutions that help to lower the electricity consumption in this sector is observed. The problem of increased energy demand for air conditioning purposes can be solved by transfer the consumption of electricity from the grid system to renewable energy sources (RES). The greatest demand for cooling occurs during the biggest sunlight. This is the basis for the analysis of technical power system based on photovoltaic cells (PV) to power the split type air conditioner. The object of the study was the commercial residential airconditioning inverter units with a capacity of 2.5kW. A network electricity production system for their own use with the possibility of buffering energy in batteries (OFF-GRID system). Currently, on the Polish market, there are no developed complete solutions dedicated to air conditioning systems based on PV. In Poland, solar energy is mainly used for heat production in solar collectors. The proposed solution will help to increase the popularity of PV systems in the Polish market as an alternative to other RES. The basic conclusion is that the amount of PV energy generated was sufficient to cover the daily energy requirement of the air conditioner.

Solar Cycle Variation and Multipoint Studies of ICME Properties

NASA Technical Reports Server (NTRS)

Russell, C. T.

2005-01-01

The goal of the Living With a Star program is to understand the Sun-Earth connection sufficiently well that we can solve problems critical to life and society. This can most effectively be done in the short term using observations from our past and on-going programs. Not only can this approach solve some of the pressing issues but also it can provide ideas for the deployment of future spacecraft in the LWS program. The proposed effort uses data from NEAR, SOHO, Wind, ACE and Pioneer Venus in quadrature, multipoint, and solar cycle studies to study the interplanetary coronal mass ejection and its role in the magnetic flux cycle of the Sun. ICMEs are most important to the LWS objectives because the solar wind conditions associated with these structures are the most geoeffective of any solar wind phenomena. Their ability to produce strong geomagnetic disturbances arises first because of their high speed. This high speed overtakes the ambient solar wind producing a bow shock wave similar to the terrestrial bow shock. In the new techniques we develop as part of this effort we exploit this feature of ICMEs. This shocked plasma has a greater velocity, higher density and stronger magnetic field than the ambient solar wind, conditions that can enhance geomagnetic activity. The driving ICME is a large magnetic structure expanding outward in the solar wind [Gosling, 19961. The ICMEs magnetic field is generally much higher than that in the ambient solar wind and the velocity is high. The twisted nature of the magnetic field in an ICME almost ensures that sometime during the ICME conditions favorable for geomagnetic storm initiation will occur.

Simulation model for assessing the efficiency of a combined power installation based on a geothermal heat pump and a vacuum solar collector

NASA Astrophysics Data System (ADS)

Vaysman, Ya I.; Surkov, AA; Surkova, Yu I.; Kychkin, AV

2017-06-01

The article is devoted to the use of renewable energy sources and the assessment of the feasibility of their use in the climatic conditions of the Western Urals. A simulation model that calculates the efficiency of a combined power installations (CPI) was (RES) developed. The CPI consists of the geothermal heat pump (GHP) and the vacuum solar collector (VCS) and is based on the research model. This model allows solving a wide range of problems in the field of energy and resource efficiency, and can be applied to other objects using RES. Based on the research recommendations for optimizing the management and the application of CPI were given. The optimization system will give a positive effect in the energy and resource consumption of low-rise residential buildings projects.

Planetary habitability: is Earth commonplace in the Milky Way?

NASA Astrophysics Data System (ADS)

Franck, S.; Block, A.; Bloh, W.; Bounama, C.; Garrido, I.; Schellnhuber, H.-J.

2001-08-01

Is there life beyond planet Earth? This is one of the grand enigmas which humankind tries to solve through scientific research. Recent progress in astronomical measurement techniques has confirmed the existence of a multitude of extra-solar planets. On the other hand, enormous efforts are being made to assess the possibility of life on Mars. All these activities have stimulated several investigations about the habitability of cosmic bodies. The habitable zone (HZ) around a given central star is defined as the region within which an Earth-like planet might enjoy the moderate surface temperatures required for advanced life forms. At present, there are several models determining the HZ. One class of models utilises climate constraints for the existence of liquid water on a planetary surface. Another approach is based on an integrated Earth system analysis that relates the boundaries of the HZ to the limits of photosynthetic processes. Within the latter approach, the evolution of the HZ for our solar system over geological time scales is calculated straightforwardly, and a convenient filter can be constructed that picks the candidates for photosynthesis-based life from all the extra-solar planets discovered by novel observational methods. These results can then be used to determine the average number of planets per planetary system that are within the HZ. With the help of a segment of the Drake equation, the number of "Gaias" (i.e. extra-solar terrestrial planets with a globally acting biosphere) is estimated. This leads to the thoroughly educated guess that there should exist half a million Gaias in the Milky Way.

Planetary habitability: is Earth commonplace in the Milky Way?

PubMed

Franck, S; Block, A; von Bloh, W; Bounama, C; Garrido, I; Schellnhuber, H J

2001-10-01

Is there life beyond planet Earth? This is one of the grand enigmas which humankind tries to solve through scientific research. Recent progress in astronomical measurement techniques has confirmed the existence of a multitude of extra-solar planets. On the other hand, enormous efforts are being made to assess the possibility of life on Mars. All these activities have stimulated several investigations about the habitability of cosmic bodies. The habitable zone (HZ) around a given central star is defined as the region within which an Earth-like planet might enjoy the moderate surface temperatures required for advanced life forms. At present, there are several models determining the HZ. One class of models utilises climate constraints for the existence of liquid water on a planetary surface. Another approach is based on an integrated Earth system analysis that relates the boundaries of the HZ to the limits of photosynthetic processes. Within the latter approach, the evolution of the HZ for our solar system over geological time scales is calculated straightforwardly, and a convenient filter can be constructed that picks the candidates for photosynthesis-based life from all the extra-solar planets discovered by novel observational methods. These results can then be used to determine the average number of planets per planetary system that are within the HZ. With the help of a segment of the Drake equation, the number of "Gaias" (i.e. extra-solar terrestrial planets with a globally acting biosphere) is estimated. This leads to the thoroughly educated guess that there should exist half a million Gaias in the Milky Way.

Presolar stardust in meteorites: recent advances and scientific frontiers

NASA Astrophysics Data System (ADS)

Nittler, Larry R.

2003-04-01

Grains of stardust that formed in stellar outflows prior to the formation of the solar system survive intact as trace constituents of primitive meteorites. The presolar origin of the grains is indicated by enormous isotopic ratio variations compared to solar system materials. Identified presolar phases include diamond, silicon carbide, graphite, silicon nitride, corundum, spinel, hibonite, titanium oxide, and, most recently, silicates. Sub-grains of refractory carbides (e.g. TiC), and Fe-Ni metal have also been observed within individual presolar graphite grains. Isotopic compositions indicate that the grains formed in red giants, asymptotic giant branch (AGB) stars, supernovae and novae; thus they provide unique insights into the evolution of and nucleosynthesis within these environments. Some of the isotopic variations also reflect the chemical evolution of the galaxy and can be used to constrain corresponding models. Presolar grain microstructures provide information about physical and chemical conditions of dust formation in stellar environments; recent studies have focused on graphite grains from supernovae as well as SiC and corundum from AGB stars. The survival of presolar grains in different classes of meteorites has important implications for early solar system evolution. Recent analytical developments, including resonance ionization mass spectrometry, high spatial resolution secondary ion mass spectrometry and site-selective ion milling, should help solve many outstanding problems but are likely to also introduce new surprises.

Constraints on decay plus oscillation solutions of the solar neutrino problem

NASA Astrophysics Data System (ADS)

Joshipura, Anjan S.; Massó, Eduard; Mohanty, Subhendra

2002-12-01

We examine the constraints on the nonradiative decay of neutrinos from the observations of solar neutrino experiments. The standard oscillation hypothesis among three neutrinos solves the solar and atmospheric neutrino problems. The decay of a massive neutrino mixed with the electron neutrino results in the depletion of the solar neutrino flux. We introduce neutrino decay in the oscillation hypothesis and demand that decay does not spoil the successful explanation of solar and atmospheric observations. We obtain a lower bound on the ratio of the lifetime over the mass of ν2, τ2/m2>22.7 s/MeV for the Mikheyev-Smirnov-Wolfenstein solution of the solar neutrino problem and τ2/m2>27.8 s/MeV for the vacuum oscillation solution (at 99% C.L.).

Modeling of the Orbital Evolution of 2060 Chiron

NASA Astrophysics Data System (ADS)

Kovalenko, Nataliya S.; Babenko, Yury G.; Churyumov, Klim I.

2002-03-01

The origin of Centaurs is one of the most interesting problems of Solar system science, and it has not yet been solved. To shed light on this problem one can investigate Centaurs' past and future orbital evolution. In this paper we discuss the results of Chiron's orbital evolution modeling. It was the first discovered Centaur and is the brightest one. Numerical integration was produced for 1 Myr forward and backward from the present time. A program based on the Everhart single sequence method for integrating orbits was used.

Non-stationarity and cross-correlation effects in the MHD solar activity

NASA Astrophysics Data System (ADS)

Demin, S. A.; Nefedyev, Y. A.; Andreev, A. O.; Demina, N. Y.; Timashev, S. F.

2018-01-01

The analysis of turbulent processes in sunspots and pores which are self-organizing long-lived magnetic structures is a complicated and not yet solved problem. The present work focuses on studying such magneto-hydrodynamic (MHD) formations on the basis of flicker-noise spectroscopy using a new method of multi-parametric analysis. The non-stationarity and cross-correlation effects taking place in solar activity dynamics are considered. The calculated maximum values of non-stationarity factor may become precursors of significant restructuring in solar magnetic activity. The introduced cross-correlation functions enable us to judge synchronization effects between the signals of various solar activity indicators registered simultaneously.

CFD analysis of supercritical CO2 used as HTF in a solar tower receiver

NASA Astrophysics Data System (ADS)

Roldán, M. I.; Fernández-Reche, J.

2016-05-01

The relative cost of a solar receiver can be minimized by the selection of an appropriate heat transfer fluid capable of achieving high receiver efficiencies. In a conventional central receiver system, the concentrated solar energy is transferred from the receiver tube walls to the heat transfer fluid (HTF), which passes through a heat exchanger to generate steam for a Rankine cycle. Thus, higher working fluid temperature is associated with greater efficiency in receiver and power cycle. Emerging receiver designs that can enable higher efficiencies using advanced power cycles, such as supercritical CO2 (s-CO2) closed-loop Brayton cycles, include direct heating of s-CO2 in tubular receiver designs capable of withstanding high internal fluid pressures (around 20 MPa) and temperatures (900 K). Due to the high pressures required and the presence of moving components installed in pipelines (ball-joints and/or flexible connections), the use of s-CO2 presents many technical challenges due to the compatibility of seal materials and fluid leakages of the moving connections. These problems are solved in solar tower systems because the receiver is fixed. In this regard, a preliminary analysis of a tubular receiver with s-CO2 as HTF has been developed using the design of a molten-salt receiver which was previously tested at Plataforma Solar de Almería (PSA). Therefore, a simplified CFD model has been carried out in this study in order to analyze the feasibility of s-CO2 as HTF in solar towers. Simulation results showed that the heat gained by s-CO2 was around 75% greater than the one captured by molten salts (fluid inlet temperature of 715 K), but at a pressure range of 7.5-9.7 MPa. Thus, the use of s-CO2 as HTF in solar tower receivers appears to be a promising alternative, taking into account both the operating conditions required and their maintenance cost.

Extrapolating Solar Dynamo Models Throughout the Heliosphere

NASA Astrophysics Data System (ADS)

Cox, B. T.; Miesch, M. S.; Augustson, K.; Featherstone, N. A.

2014-12-01

There are multiple theories that aim to explain the behavior of the solar dynamo, and their associated models have been fiercely contested. The two prevailing theories investigated in this project are the Convective Dynamo model that arises from the pure solving of the magnetohydrodynamic equations, as well as the Babcock-Leighton model that relies on sunspot dissipation and reconnection. Recently, the supercomputer simulations CASH and BASH have formed models of the behavior of the Convective and Babcock-Leighton models, respectively, in the convective zone of the sun. These models show the behavior of the models within the sun, while much less is known about the effects these models may have further away from the solar surface. The goal of this work is to investigate any fundamental differences between the Convective and Babcock-Leighton models of the solar dynamo outside of the sun and extending into the solar system via the use of potential field source surface extrapolations implemented via python code that operates on data from CASH and BASH. The use of real solar data to visualize supergranular flow data in the BASH model is also used to learn more about the behavior of the Babcock-Leighton Dynamo. From the process of these extrapolations it has been determined that the Babcock-Leighton model, as represented by BASH, maintains complex magnetic fields much further into the heliosphere before reverting into a basic dipole field, providing 3D visualisations of the models distant from the sun.

CNO and pep solar neutrino measurements and perspectives in Borexino

NASA Astrophysics Data System (ADS)

Davini, S.; Agostini, M.; Appel, S.; Bellini, G.; Benziger, J.; Bick, D.; Bonfini, G.; Bravo, D.; Caccianiga, B.; Calaprice, F.; Caminata, A.; Cavalcante, P.; Chepurnov, A.; D'Angelo, D.; Derbin, A.; Di Noto, L.; Drachnev, I.; Etenko, A.; Fomenko, K.; Franco, D.; Gabriele, F.; Galbiati, C.; Ghiano, C.; Giammarchi, M.; Goeger-Neff, M.; Goretti, A.; Gromov, M.; Hagner, C.; Hungerford, E.; Ianni, Aldo; Ianni, Andrea; Jedrzejczak, K.; Kaiser, M.; Kobychev, V.; Korablev, D.; Korga, G.; Kryn, D.; Laubenstein, M.; Lehnert, B.; Litvinovich, E.; Lombardi, F.; Lombardi, P.; Ludhova, L.; Lukyanchenko, G.; Machulin, I.; Manecki, S.; Maneschg, W.; Marcocci, S.; Meroni, E.; Meyer, M.; Miramonti, L.; Misiaszek, M.; Montuschi, M.; Mosteiro, P.; Muratova, V.; Neumair, B.; Oberauer, L.; Obolensky, M.; Ortica, F.; Pallavicini, M.; Papp, L.; Perasso, L.; Pocar, A.; Ranucci, G.; Razeto, A.; Re, A.; Romani, A.; Roncin, R.; Rossi, N.; Schönert, S.; Semenov, D.; Simgen, H.; Skorokhvatov, M.; Smirnov, O.; Sotnikov, A.; Sukhotin, S.; Suvorov, Y.; Tartaglia, R.; Testera, G.; Thurn, J.; Toropova, M.; Unzhakov, E.; Vishneva, A.; Vogelaar, R. B.; von Feilitzsch, F.; Wang, H.; Weinz, S.; Winter, J.; Wojcik, M.; Wurm, M.; Yokley, Z.; Zaimidoroga, O.; Zavatarelli, S.; Zuber, K.; Zuzel, G.

2016-02-01

The detection of neutrinos emitted in the CNO reactions in the Sun is one of the ambitious goals of Borexino Phase-II. A measurement of CNO neutrinos would be a milestone in astrophysics, and would allow to solve serious issues in current solar models. A precise measurement of the rate of neutrinos from the pep reaction would allow to investigate neutrino oscillations in the MSW transition region. The pep and CNO solar neutrino physics, the measurement in Borexino Phase-I and the perspectives for the new phase are reviewed in this proceeding.

Maximum performance of solar heat engines: Discussion of thermodynamic availability and other second law considerations and their implications

NASA Astrophysics Data System (ADS)

Boehm, R. F.

1985-09-01

A review of thermodynamic principles is given in an effort to see if these concepts may indicate possibilities for improvements in solar central receiver power plants. Aspects related to rate limitations in cycles, thermodynamic availability of solar radiation, and sink temperature considerations are noted. It appears that considerably higher instantaneous plant efficiencies are possible by raising the maximum temperature and lowering the minimum temperature of the cycles. Of course, many practical engineering problems will have to be solved to realize the promised benefits.

Wireless Power Transmission Options for Space Solar Power

NASA Technical Reports Server (NTRS)

Potter, Seth; Davis, Dean; Born, Martin; Bayer, Martin; Howell, Joe; Mankins, John

2008-01-01

Space Solar Power (SSP), combined with Wireless Power Transmission (WPT), offers the far-term potential to solve major energy problems on Earth. In the long term, we aspire to beam energy to Earth from geostationary Earth orbit (GEO), or even further distances in space. In the near term, we can beam power over more moderate distances, but still stretch the limits of today s technology. In recent studies, a 100 kWe-class "Power Plug" Satellite and a 10 kWe-class Lunar Polar Solar Power outpost have been considered as the first steps in using these WPT options for SSP. Our current assessments include consideration of orbits, wavelengths, and structural designs to meet commercial, civilian government, and military needs. Notional transmitter and receiver sizes are considered for use in supplying 5 to 40 MW of power. In the longer term, lunar or asteroidal material can be used. By using SSP and WPT technology for near-term missions, we gain experience needed for sound decisions in designing and developing larger systems to send power from space to Earth.

Wireless Power Transmission Options for Space Solar Power

NASA Technical Reports Server (NTRS)

Potter, Seth; Henley, Mark; Davis, Dean; Born, Andrew; Howell, Joe; Mankins, John

2008-01-01

Space Solar Power (SSP), combined with Wireless Power Transmission (WPT), offers the far-term potential to solve major energy problems on Earth. In the long-term, we aspire to beam energy to Earth from geostationary Earth orbit (GEO), or even further distances in space. In the near-term, we can beam power over more moderate distances, but still stretch the limits of today s technology. In recent studies, a 100 kWe-class "Power Plug" Satellite and a 10 kWe-class Lunar Polar Solar Power outpost have been considered as the first steps in using these WPT options for SSP. Our current assessments include consideration of orbits, wavelengths, and structural designs to meet commercial, civilian government, and military needs. Notional transmitter and receiver sizes are considered for use in supplying 5 to 15 MW of power. In the longer term, lunar or asteroidal material can be used. By using SSP and WPT technology for near-term missions, we gain experience needed for sound decisions in designing and developing larger systems to send power from space to Earth.

Wireless Power Transmission Options for Space Solar Power

NASA Technical Reports Server (NTRS)

Henley, Mark; Potter, Seth; Howell, Joseph; Mankins, John

2002-01-01

Space Solar Power (SSP), combined with Wireless Power Transmission (WPT), offers the far-term potential to solve major energy problems on Earth. In this paper two basic WPT options, using radio waves and light waves, are considered for both long-term and near-term SSP applications. In the long-term, we aspire to beam energy to Earth from geostationary Earth orbit (GEO), or even further distances in space. Accordingly, radio- and light- wave WPT options are compared through a wide range of criteria, each showing certain strengths. In the near-term, we plan to beam power over more moderate distances, but still stretch the limits of today's technology. For the near-term, a 100 kWe-class 'Power Plug' Satellite and a 10 kWe-class Lunar Polar Solar Power outpost are considered as the first steps in using these WPT options for SSP. By using SSP and WPT technology in near-term space science and exploration missions, we gain experience needed for sound decisions in designing and developing larger systems to send power from Space to Earth.

Wireless Power Transmission Options for Space Solar Power

NASA Technical Reports Server (NTRS)

Henley, Mark; Potter, Seth; Howell, Joseph; Mankins, John

2007-01-01

Space Solar Power (SSP), combined with Wireless Power Transmission (WPT), offers the far-term potential to solve major energy problems on Earth. In this presentation, two basic WPT options, using radio waves an d light waves, are considered for both long-term and near-term SSP applications. In the long-term, we aspire to beam energy to Earth from geostationary Earth orbit (GEO), or even further distances in space. Accordingly, radio- and light- wave WPT options are compared through a wide range of criteria, each showing certain strengths. In the near-term, we plan to beam power over more moderate distances, but still stretch the limits of today's technology. For the near-term, a 100 kWe-class "Power Plug" Satellite and a 10 kWe-class Lunar Polar Solar Power outpost are considered as the first steps in using these WPT options for SSP. By using SSP and WPT technology in nearterm space science and exploration missions, we gain experience needed for sound decisions in designing and developing larger systems to send power from Space to Earth.

Eta Carinae: A Box of Puzzles...Some Solved, Others Await

NASA Technical Reports Server (NTRS)

Gull, Theodore

2010-01-01

In the l840's, Eta Carinae brightened to rival Sirius, then faded. Today we see a marginally naked-eye binary with an expanding, very dusty bipolar Homunculus. The energetics of the ejected mass (>l2 to 40 solar masses at 500-700 km/s plus outer bullets/strings up to 3000 km/s} approach that of a supernova. Extragalactic SN surveys detect near-supernovae thought to be like the Great Eruption of the 1840's. Eta Carinae presents an abundance of puzzles: rich in N, but 1/100th the solar C and O abundances; Ti, V, Sr, Sc persist in atomic states.... yet an abundance of molecules and dust exists in the Homunculus. How did molecules and dust form with low C and O? A near supernova occurred in the l840m, yet both binary companions, with total mass > 120 solar masses, survive in a very eccentric orbit. What is the near future of this system: a GRB? a SN? or just two WR stars that ultimately become two SNs? These and other puzzles will be presented

SMALL-SCALE SOLAR WIND TURBULENCE DUE TO NONLINEAR ALFVÉN WAVES

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

Kumar, Sanjay; Moon, Y.-J.; Sharma, R. P., E-mail: sanjaykumar@khu.ac.kr

We present an evolution of wave localization and magnetic power spectra in solar wind plasma using kinetic Alfvén waves (AWs) and fast AWs. We use a two-fluid model to derive the dynamical equations of these wave modes and then numerically solve these nonlinear dynamical equations to analyze the power spectra and wave localization at different times. The ponderomotive force associated with the kinetic AW (or pump) is responsible for the wave localization, and these thin slabs (or sheets) become more chaotic as the system evolves with time until the modulational instability (or oscillating two-stream instability) saturates. From our numerical results,more » we notice a steepening of the spectra from the inertial range (k{sup −1.67}) to the dispersion range (k{sup −3.0}). The steepening of the spectra could be described as the energy transference from longer to smaller scales. The formation of complex magnetic thin slabs and the change of the spectral index may be considered to be the main reason for the charged particles acceleration in solar wind plasma.« less

Simulations of Solar Wind Turbulence

NASA Technical Reports Server (NTRS)

Goldstein, Melvyn L.; Usmanov, A. V.; Roberts, D. A.

2008-01-01

Recently we have restructured our approach to simulating magnetohydrodynamic (MHD) turbulence in the solar wind. Previously, we had defined a 'virtual' heliosphere that contained, for example, a tilted rotating current sheet, microstreams, quasi-two-dimensional fluctuations as well as Alfven waves. In this new version of the code, we use the global, time-stationary, WKB Alfven wave-driven solar wind model developed by Usmanov and described in Usmanov and Goldstein [2003] to define the initial state of the system. Consequently, current sheets, and fast and slow streams are computed self-consistently from an inner, photospheric, boundary. To this steady-state configuration, we add fluctuations close to, but above, the surface where the flow become super-Alfvenic. The time-dependent MHD equations are then solved using a semi-discrete third-order Central Weighted Essentially Non-Oscillatory (CWENO) numerical scheme. The computational domain now includes the entire sphere; the geometrical singularity at the poles is removed using the multiple grid approach described in Usmanov [1996]. Wave packets are introduced at the inner boundary such as to satisfy Faraday's Law [Yeh and Dryer, 1985] and their nonlinear evolution are followed in time.

Numerical study on the effect of configuration of a simple box solar cooker for boiling water

NASA Astrophysics Data System (ADS)

Ambarita, H.

2018-02-01

In this work, a numerical study is carried out to investigate the effect of configuration of a simple box solar cooker. In order to validate the numerical results, a simple a simple solar box cooker with absorber area of 0.835 m × 0.835 m is designed and fabricated. The solar box cooker is employed to boil water by exposing to the solar radiation in Medan city of Indonesia. In the numerical method, a set of transient governing equations are developed. The governing equations are solved using forward time step marching technique. The main objective is to explore the effect of double glasses cover, dimensions of the cooking vessel, and depth of the box cooker to the performance of the solar box cooker. The results show that the experimental and numerical results show good agreement. The performance of the solar box cooker strongly affected by the distance of the double glass cover, the solar cooker depth, and the solar collector length.

Singularity free N-body simulations called 'Dynamic Universe Model' don't require dark matter

NASA Astrophysics Data System (ADS)

Naga Parameswara Gupta, Satyavarapu

For finding trajectories of Pioneer satellite (Anomaly), New Horizons satellite going to Pluto, the Calculations of Dynamic Universe model can be successfully applied. No dark matter is assumed within solar system radius. The effect on the masses around SUN shows as though there is extra gravitation pull toward SUN. It solves the Dynamics of Extra-solar planets like Planet X, satellite like Pioneer and NH for 3-Position, 3-velocity 3-accelaration for their masses, considering the complex situation of Multiple planets, Stars, Galaxy parts and Galaxy centre and other Galaxies Using simple Newtonian Physics. It already solved problems Missing mass in Galaxies observed by galaxy circular velocity curves successfully. Singularity free Newtonian N-body simulations Historically, King Oscar II of Sweden an-nounced a prize to a solution of N-body problem with advice given by Güsta Mittag-Leffler in 1887. He announced `Given a system of arbitrarily many mass points that attract each according to Newton's law, under the assumption that no two points ever collide, try to find a representation of the coordinates of each point as a series in a variable that is some known function of time and for all of whose values the series converges uniformly.'[This is taken from Wikipedia]. The announced dead line that time was1st June 1888. And after that dead line, on 21st January 1889, Great mathematician Poincaré claimed that prize. Later he himself sent a telegram to journal Acta Mathematica to stop printing the special issue after finding the error in his solution. Yet for such a man of science reputation is important than money. [ Ref Book `Celestial mechanics: the waltz of the planets' By Alessandra Celletti, Ettore Perozzi, page 27]. He realized that he has been wrong in his general stability result! But till now nobody could solve that problem or claimed that prize. Later all solutions resulted in singularities and collisions of masses, given by many people . . . . . . . . . . . . . . . . . . . . . . . . .. Now I can say that the Dynamic Universe Model solves this classical N-body problem where only Newtonian Gravi-tation law and classical Physics were used. The solution converges at all points. There are no multiple values, diverging solutions or divided by zero singularities. Collisions of masses depend on physical values of masses and their space distribution only. These collisions do not happen due to internal inherent problems of Dynamic universe Model. If the mass distribution is homogeneous and isotropic, the masses will colloid. If the mass distribution is heterogeneous and anisotropic, they do not colloid. This approach solves many problems which otherwise can not be solved by General relativity, Steady state universe model etc. . .

Using Decision Procedures to Build Domain-Specific Deductive Synthesis Systems

NASA Technical Reports Server (NTRS)

VanBaalen, Jeffrey; Roach, Steven; Lau, Sonie (Technical Monitor)

1998-01-01

This paper describes a class of decision procedures that we have found useful for efficient, domain-specific deductive synthesis. These procedures are called closure-based ground literal satisfiability procedures. We argue that this is a large and interesting class of procedures and show how to interface these procedures to a theorem prover for efficient deductive synthesis. Finally, we describe some results we have observed from our implementation. Amphion/NAIF is a domain-specific, high-assurance software synthesis system. It takes an abstract specification of a problem in solar system mechanics, such as 'when will a signal sent from the Cassini spacecraft to Earth be blocked by the planet Saturn?', and automatically synthesizes a FORTRAN program to solve it.

Modeling and optimization of a hybrid solar combined cycle (HYCS)

NASA Astrophysics Data System (ADS)

Eter, Ahmad Adel

2011-12-01

The main objective of this thesis is to investigate the feasibility of integrating concentrated solar power (CSP) technology with the conventional combined cycle technology for electric generation in Saudi Arabia. The generated electricity can be used locally to meet the annual increasing demand. Specifically, it can be utilized to meet the demand during the hours 10 am-3 pm and prevent blackout hours, of some industrial sectors. The proposed CSP design gives flexibility in the operation system. Since, it works as a conventional combined cycle during night time and it switches to work as a hybrid solar combined cycle during day time. The first objective of the thesis is to develop a thermo-economical mathematical model that can simulate the performance of a hybrid solar-fossil fuel combined cycle. The second objective is to develop a computer simulation code that can solve the thermo-economical mathematical model using available software such as E.E.S. The developed simulation code is used to analyze the thermo-economic performance of different configurations of integrating the CSP with the conventional fossil fuel combined cycle to achieve the optimal integration configuration. This optimal integration configuration has been investigated further to achieve the optimal design of the solar field that gives the optimal solar share. Thermo-economical performance metrics which are available in the literature have been used in the present work to assess the thermo-economic performance of the investigated configurations. The economical and environmental impact of integration CSP with the conventional fossil fuel combined cycle are estimated and discussed. Finally, the optimal integration configuration is found to be solarization steam side in conventional combined cycle with solar multiple 0.38 which needs 29 hectare and LEC of HYCS is 63.17 $/MWh under Dhahran weather conditions.

Detecting Exoplanets with the New Worlds Observer: The Problem of Exozodiacal Dust

NASA Technical Reports Server (NTRS)

Roberge, A.; Noecker, M. C.; Glassman, T. M.; Oakley, P.; Turnbull, M. C.

2009-01-01

Dust coming from asteroids and comets will strongly affect direct imaging and characterization of terrestrial planets in the Habitable Zones of nearby stars. Such dust in the Solar System is called the zodiacal dust (or 'zodi' for short). Higher levels of similar dust are seen around many nearby stars, confined in disks called debris disks. Future high-contrast images of an Earth-like exoplanet will very likely be background-limited by light scattered of both the local Solar System zodi and the circumstellar dust in the extrasolar system (the exozodiacal dust). Clumps in the exozodiacal dust, which are expected in planet-hosting systems, may also be a source of confusion. Here we discuss the problems associated with imaging an Earth-like planet in the presence of unknown levels of exozodiacal dust. Basic formulae for the exoplanet imaging exposure time as function of star, exoplanet, zodi, exozodi, and telescope parameters will be presented. To examine the behavior of these formulae, we apply them to the New Worlds Observer (NWO) mission. NWO is a proposed 4-meter UV/optical/near-IR telescope, with a free flying starshade to suppress the light from a nearby star and achieve the high contrast needed for detection and characterization of a terrestrial planet in the star's Habitable Zone. We find that NWO can accomplish its science goals even if exozodiacal dust levels are typically much higher than the Solar System zodi level. Finally, we highlight a few additional problems relating to exozodiacal dust that have yet to be solved.

Computational helioseismology in the frequency domain: acoustic waves in axisymmetric solar models with flows

NASA Astrophysics Data System (ADS)

Gizon, Laurent; Barucq, Hélène; Duruflé, Marc; Hanson, Chris S.; Leguèbe, Michael; Birch, Aaron C.; Chabassier, Juliette; Fournier, Damien; Hohage, Thorsten; Papini, Emanuele

2017-04-01

Context. Local helioseismology has so far relied on semi-analytical methods to compute the spatial sensitivity of wave travel times to perturbations in the solar interior. These methods are cumbersome and lack flexibility. Aims: Here we propose a convenient framework for numerically solving the forward problem of time-distance helioseismology in the frequency domain. The fundamental quantity to be computed is the cross-covariance of the seismic wavefield. Methods: We choose sources of wave excitation that enable us to relate the cross-covariance of the oscillations to the Green's function in a straightforward manner. We illustrate the method by considering the 3D acoustic wave equation in an axisymmetric reference solar model, ignoring the effects of gravity on the waves. The symmetry of the background model around the rotation axis implies that the Green's function can be written as a sum of longitudinal Fourier modes, leading to a set of independent 2D problems. We use a high-order finite-element method to solve the 2D wave equation in frequency space. The computation is embarrassingly parallel, with each frequency and each azimuthal order solved independently on a computer cluster. Results: We compute travel-time sensitivity kernels in spherical geometry for flows, sound speed, and density perturbations under the first Born approximation. Convergence tests show that travel times can be computed with a numerical precision better than one millisecond, as required by the most precise travel-time measurements. Conclusions: The method presented here is computationally efficient and will be used to interpret travel-time measurements in order to infer, e.g., the large-scale meridional flow in the solar convection zone. It allows the implementation of (full-waveform) iterative inversions, whereby the axisymmetric background model is updated at each iteration.

FUPSOL: Modelling the Future and Past Solar Influence on Earth Climate

NASA Astrophysics Data System (ADS)

Anet, J. G.; Rozanov, E.; Peter, T.

2012-04-01

Global warming is becoming one of the main threats to mankind. There is growing evidence that anthropogenic greenhouse gases have become the dominant factor since about 1970. At the same time natural factors of climate change such as solar and volcanic forcings cannot be neglected on longer time scales. Despite growing scientific efforts over the last decades in both, observations and simulations, the uncertainty of the solar contribution to the past climate change remained unacceptably high (IPCC, 2007), the reasons being on one hand missing observations of solar irradiance prior to the satellite era, and on the other hand a majority of models so far not including all processes relevant for solar-climate interactions. This project aims at elucidating the processes governing the effects of solar activity variations on Earth's climate. We use the state-of-the-art coupled atmosphere-ocean-chemistry-climate model (AOCCM) SOCOL (Schraner et al, 2008) developed in Switzerland by coupling the community Earth System Model (ESM) COSMOS distributed by MPI for Meteorology (Hamburg, Germany) with a comprehensive atmospheric chemistry module. The model solves an extensive set of equations describing the dynamics of the atmosphere and ocean, radiative transfer, transport of species, their chemical transformations, cloud formation and the hydrological cycle. The intention is to show how past solar variations affected climate and how the decrease in solar forcing expected for the next decades will affect climate on global and regional scales. We will simulate the global climate system behavior during Dalton minimum (1790 and 1830) and first half of 21st century with a series of multiyear ensemble experiments and perform these experiments using all known anthropogenic and natural climate forcing taken in different combinations to understand the effects of solar irradiance in different spectral regions and particle precipitation variability. Further on, we will quantify the solar influence on global climate in the future by evaluating the simulations and using information from past analogs such as the Dalton minimum. In the end, the project aims at reducing the uncertainty of the solar contribution to past and future climate change, which so far remained high despite many years of analyses of observational records and theoretical investigations with climate models of different complexity.

The dynamics and control of solar-sail spacecraft in displaced lunar orbits

NASA Astrophysics Data System (ADS)

Wawrzyniak, Geoffrey George

Trajectory generation for any spacecraft mission application typically involves either well-developed analytical approximations or a linearization with respect to a known solution. Such approximations are based on the well-understood dynamics of behavior in the system. However, when two or more large bodies (e.g., the Earth and the Moon or the Sun, the Earth and the Moon) are present, trajectories in the multi-body gravitational field can evolve chaotically. The problem is further complicated when an additional force from a solar sail is included. Solar sail trajectories are often developed in a Sun-centered reference frame in which the sunlight direction is fixed. New challenges arise when modeling a solar-sail trajectory in a reference frame attached to the Earth and the Moon (a frame that rotates in inertial space). Advantages accrue from geometry and symmetry properties that are available in this Earth--Moon reference frame, but the Sun location and the sunlight direction change with time. Current trajectory design tools can reveal many solutions within these regimes. Recent work using numerical boundary value problem (BVP) solvers has demonstrated great promise for uncovering additional and, sometimes, "better" solutions to problems in spacecraft trajectory design involving solar sails. One such approach to solving BVPs is the finite-difference method. Derivatives that appear in the differential equations are replaced with their respective finite differences and evaluated at node points along the trajectory. The solution process is iterative. A candidate solution, such as an offset circle or a point, is discretized into nodes, and the equations that represent the relationships at the nodes are solved simultaneously. Finite-difference methods (FDMs) exploit coarse initial approximations and, with the system constraints (such as the continuous visibility of the spacecraft from a point on the lunar surface), to develop orbital solutions in regions where the structure of the solution space is not well known. Because of their simplicity and speed, the FDM is used to populate a survey to assist in the understanding of the available design space. Trajectories generated by FDMs can also be used to initialize other nonlinear BVP solvers. Any solution is only as accurate as the model used to generate it, especially when the trajectory is dynamically unstable, certainly the case when an orbit is purposefully offset from the Moon. Perturbations, such as unmodeled gravitational forces, variations in the solar flux, as well as mis-modeling of the sail and bus properties, all shift the spacecraft off the reference trajectory and, potentially, into a regime from which the vehicle is unrecoverable. Therefore, some type of flight-path control is required to maintain the vehicle near the reference path. Reference trajectories, supplied by FDMs, are used to develop guidance algorithms based on other, more accurate, numerical procedures, such as multiple shooting. The primary motivation of this investigation is to determine what level of technology is required to displace a solar sail spacecraft sufficiently such that a vehicle equipped with a sail supplies a continuous relay between the Earth and an outpost at the lunar south pole. To accomplish this objective, numerical methods to generate reference orbits that meet mission constraints are examined, as well as flight-path control strategies to ensure that a sailcraft follows those reference trajectories. A survey of the design space is also performed to highlight vehicle-performance and ground-based metrics critical to a mission that monitors the lunar south pole at all times. Finally, observations about the underlying dynamical structure of solar sail motion in a multi-body system are summarized.

Improved methods for nightside time domain Lunar Electromagnetic Sounding

NASA Astrophysics Data System (ADS)

Fuqua-Haviland, H.; Poppe, A. R.; Fatemi, S.; Delory, G. T.; De Pater, I.

2017-12-01

Time Domain Electromagnetic (TDEM) Sounding isolates induced magnetic fields to remotely deduce material properties at depth. The first step of performing TDEM Sounding at the Moon is to fully characterize the dynamic plasma environment, and isolate geophysically induced currents from concurrently present plasma currents. The transfer function method requires a two-point measurement: an upstream reference measuring the pristine solar wind, and one downstream near the Moon. This method was last performed during Apollo assuming the induced fields on the nightside of the Moon expand as in an undisturbed vacuum within the wake cavity [1]. Here we present an approach to isolating induction and performing TDEM with any two point magnetometer measurement at or near the surface of the Moon. Our models include a plasma induction model capturing the kinetic plasma environment within the wake cavity around a conducting Moon, and a geophysical forward model capturing induction in a vacuum. The combination of these two models enable the analysis of magnetometer data within the wake cavity. Plasma hybrid models use the upstream plasma conditions and interplanetary magnetic field (IMF) to capture the wake current systems formed around the Moon. The plasma kinetic equations are solved for ion particles with electrons as a charge-neutralizing fluid. These models accurately capture the large scale lunar wake dynamics for a variety of solar wind conditions: ion density, temperature, solar wind velocity, and IMF orientation [2]. Given the 3D orientation variability coupled with the large range of conditions seen within the lunar plasma environment, we characterize the environment one case at a time. The global electromagnetic induction response of the Moon in a vacuum has been solved numerically for a variety of electrical conductivity models using the finite-element method implemented within the COMSOL software. This model solves for the geophysically induced response in vacuum to any driving transient event for any specified 3D conductivity profile. Our models fit the analytic solutions to a Root-Mean-Square Error of better than 1%. Solutions are non-unique, however, serve to better understand and constrain the global interior composition and 3D structure of the Moon. [1] Dyal & Parkin (1971) JGR; [2] Fatemi et al. (2013) GRL.

The effect of beam-driven return current instability on solar hard X-ray bursts

NASA Technical Reports Server (NTRS)

Cromwell, D.; Mcquillan, P.; Brown, J. C.

1986-01-01

The problem of electrostatic wave generation by a return current driven by a small area electron beam during solar hard X-ray bursts is discussed. The marginal stability method is used to solve numerically the electron and ion heating equations for a prescribed beam current evolution. When ion-acoustic waves are considered, the method appears satisfactory and, following an initial phase of Coulomb resistivity in which T sub e/T sub i rise, predicts a rapid heating of substantial plasma volumes by anomalous ohmic dissipation. This hot plasma emits so much thermal bremsstrahlung that, contrary to previous expectations, the unstable beam-plasma system actually emits more hard X-rays than does the beam in the purely collisional thick target regime relevant to larger injection areas. Inclusion of ion-cyclotron waves results in ion-acoustic wave onset at lower T sub e/T sub i and a marginal stability treatment yields unphysical results.

Data-driven modeling of solar-powered urban microgrids

PubMed Central

Halu, Arda; Scala, Antonio; Khiyami, Abdulaziz; González, Marta C.

2016-01-01

Distributed generation takes center stage in today’s rapidly changing energy landscape. Particularly, locally matching demand and generation in the form of microgrids is becoming a promising alternative to the central distribution paradigm. Infrastructure networks have long been a major focus of complex networks research with their spatial considerations. We present a systemic study of solar-powered microgrids in the urban context, obeying real hourly consumption patterns and spatial constraints of the city. We propose a microgrid model and study its citywide implementation, identifying the self-sufficiency and temporal properties of microgrids. Using a simple optimization scheme, we find microgrid configurations that result in increased resilience under cost constraints. We characterize load-related failures solving power flows in the networks, and we show the robustness behavior of urban microgrids with respect to optimization using percolation methods. Our findings hint at the existence of an optimal balance between cost and robustness in urban microgrids. PMID:26824071

Data-driven modeling of solar-powered urban microgrids.

PubMed

Halu, Arda; Scala, Antonio; Khiyami, Abdulaziz; González, Marta C

2016-01-01

Distributed generation takes center stage in today's rapidly changing energy landscape. Particularly, locally matching demand and generation in the form of microgrids is becoming a promising alternative to the central distribution paradigm. Infrastructure networks have long been a major focus of complex networks research with their spatial considerations. We present a systemic study of solar-powered microgrids in the urban context, obeying real hourly consumption patterns and spatial constraints of the city. We propose a microgrid model and study its citywide implementation, identifying the self-sufficiency and temporal properties of microgrids. Using a simple optimization scheme, we find microgrid configurations that result in increased resilience under cost constraints. We characterize load-related failures solving power flows in the networks, and we show the robustness behavior of urban microgrids with respect to optimization using percolation methods. Our findings hint at the existence of an optimal balance between cost and robustness in urban microgrids.

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

Chae, Kyu-Hyun; Kravtsov, Andrey V.; Frieman, Joshua A.

With SDSS galaxy data and halo data from up-to-date N-body simulations we construct a semi-empirical catalog (SEC) of early-type systems by making a self-consistent bivariate statistical match of stellar mass (M_star) and velocity dispersion (sigma) with halo virial mass (M_vir). We then assign stellar mass profile and velocity dispersion profile parameters to each system in the SEC using their observed correlations with M_star and sigma. Simultaneously, we solve for dark matter density profile of each halo using the spherical Jeans equation. The resulting dark matter density profiles deviate in general from the dissipationless profile of NFW or Einasto and theirmore » mean inner density slope and concentration vary systematically with M_vir. Statistical tests of the distribution of profiles at fixed M_vir rule out the null hypothesis that it follows the distribution predicted by N-body simulations for M_vir ~< 10^{13.5-14.5} M_solar. These dark matter profiles imply that dark matter density is, on average, enhanced significantly in the inner region of halos with M_vir ~< 10^{13.5-14.5} M_solar supporting halo contraction. The main characteristics of halo contraction are: (1) the mean dark matter density within the effective radius has increased by a factor varying systematically up to ~ 3-4 at M_vir = 10^{12} M_solar, and (2) the inner density slope has a mean of ~ 1.3 with rho(r) ~ r^{-alpha} and a halo-to-halo rms scatter of rms(alpha) ~ 0.4-0.5 for 10^{12} M_solar ~< M_vir ~< 10^{13-14} M_solar steeper than the NFW profile (alpha=1). Based on our results we predict that halos of nearby elliptical and lenticular galaxies can, in principle, be promising targets for gamma-ray emission from dark matter annihilation.« less

Optimal Renewable Energy Integration into Refinery with CO2 Emissions Consideration: An Economic Feasibility Study

NASA Astrophysics Data System (ADS)

Alnifro, M.; Taqvi, S. T.; Ahmad, M. S.; Bensaida, K.; Elkamel, A.

2017-08-01

With increasing global energy demand and declining energy return on energy invested (EROEI) of crude oil, global energy consumption by the O&G industry has increased drastically over the past few years. In addition, this energy increase has led to an increase GHG emissions, resulting in adverse environmental effects. On the other hand, electricity generation through renewable resources have become relatively cost competitive to fossil based energy sources in a much ‘cleaner’ way. In this study, renewable energy is integrated optimally into a refinery considering costs and CO2 emissions. Using Aspen HYSYS, a refinery in the Middle East was simulated to estimate the energy demand by different processing units. An LP problem was formulated based on existing solar energy systems and wind potential in the region. The multi-objective function, minimizing cost as well as CO2 emissions, was solved using GAMS to determine optimal energy distribution from each energy source to units within the refinery. Additionally, an economic feasibility study was carried out to determine the viability of renewable energy technology project implementation to overcome energy requirement of the refinery. Electricity generation through all renewable energy sources considered (i.e. solar PV, solar CSP and wind) were found feasible based on their low levelized cost of electricity (LCOE). The payback period for a Solar CSP project, with an annual capacity of about 411 GWh and a lifetime of 30 years, was found to be 10 years. In contrast, the payback period for Solar PV and Wind were calculated to be 7 and 6 years, respectively. This opens up possibilities for integrating renewables into the refining sector as well as optimizing multiple energy carrier systems within the crude oil industry

Technology Education Tackles Energy Crisis.

ERIC Educational Resources Information Center

Cutshall, Sandy

2002-01-01

Describes the solar-hydrogen technologies at the East Valley Institute of Technology, the only technology center in the nations that offers this class. Describes its focus on solving the energy crisis. (JOW)

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

Malikopoulos, Andreas; Djouadi, Seddik M; Kuruganti, Teja

We consider the optimal stochastic control problem for home energy systems with solar and energy storage devices when the demand is realized from the grid. The demand is subject to Brownian motions with both drift and variance parameters modulated by a continuous-time Markov chain that represents the regime of electricity price. We model the systems as pure stochastic differential equation models, and then we follow the completing square technique to solve the stochastic home energy management problem. The effectiveness of the efficiency of the proposed approach is validated through a simulation example. For practical situations with constraints consistent to thosemore » studied here, our results imply the proposed framework could reduce the electricity cost from short-term purchase in peak hour market.« less

The formation of the planetary system

NASA Astrophysics Data System (ADS)

Tscharnuter, W. M.

1984-12-01

The basic ideas concerning solar system formation were developed by Kant (1755) and Laplace (1796) whose starting point was the so-called nebular hypothesis. The great advantage of the nebular hypothesis is that many regularities, e.g. prograde motions of all planets and asteroids in almost coplanar orbits, can be explained. Observations in the radio and infrared region strongly support the nebular hypothesis provided that the angular momentum problem can be solved in some way. Three possibilities are listed: (1) magnetic fields via Alfvén waves which can transport angular momentum from the contracting cloud fragment into the external medium, (2) turbulent friction, (3) gravitational torques exerted by high amplitude spiral or bar-like density waves in the nebula.

Isolated Operation at Hachinohe Micro-Grid Project

NASA Astrophysics Data System (ADS)

Takano, Tomihiro; Kojima, Yasuhiro; Temma, Koji; Simomura, Masaru

To meet the global warming, renewable energy sources like wind, solar and biomass generations are dramatically increasing. Cogeneration systems are also ever-growing to save consumers' energy costs among factories, buildings and homes where lots of thermal loads are expected. According to these dispersed generators growth, their negative impacts to commercial power systems quality become non-negligible, because their unstable output causes network voltage and frequency fluctuation. Micro-grid technology comes to the front to solve the problem and many demonstrative field tests are now going all over the world. This paper presents the control paradigm and its application to Hachinohe micro-gird project, especially focusing on the power quality at isolated operation on which strict condition is imposed.

Producing propellants from water in lunar soil using solar lasers

NASA Astrophysics Data System (ADS)

de Morais Mendonca Teles, Antonio

The exploration of the Solar System is directly related to the efficiency of engines designed to explore it, and consequently, to the propulsion techniques, materials and propellants for those engines. With the present day propulsion techniques it is necessary great quantities of propellants to impulse a manned spacecraft to Mars and beyond in the Solar System, which makes these operations financially very expensive because of the costs involved in launching it from planet Earth, due to its high gravity field strength. To solve this problem, it is needed a planetary place with smaller gravity field strength, near to the Earth and with great quantities of substances at the surface necessary for the in-situ production of propellants for spacecrafts. The only place available is Earth's natural satellite the Moon. So, here in this paper, I propose the creation of a Lunar Propellant Manufacturer. It is a robot-spacecraft which can be launched from Earth using an Energia Rocket, and to land on the Moon in an area (principally near to the north pole where it was discovered water molecules ice recently) with great quantities of oxygen and hydrogen (propellants) in the silicate soil, previously observed and mapped by spacecrafts in lunar orbit, for the extraction of those molecules from the soil and the in-situ production of the necessary propellants. The Lunar Propellant Manufacturer (LPM) spacecraft consists of: 1) a landing system with four legs (extendable) and rovers -when the spacecraft touches down, the legs retract in order that two apparatuses, analogue to tractor's wheeled belts parallel sided and below the spacecraft, can touch firmly the ground -it will be necessary for the displacement of the spacecraft to new areas with richer propellants content, when the early place has already exhausted in propellants; 2) a digging machine -a long, resistant extendable arm with an excavator hand, in the outer part of the spacecraft -it will extend itself to the ground, collect soil and retract itself to put the material on the top of the spacecraft inside a hole which will be opened; 3) an infrared laser based on solar electrical energy -a "solar laser" -when the soil be inside the chamber inside the spacecraft, the solar laser will be turned on and it will strike against the soil, heating it up, and release all oxygen and hydrogen from it. The oxygen and hydrogen molecules will be separated from the rest of the material by a mass spectrometer and they will be liquefied by thermal and pressure internal control sub-systems of the spacecraft, and pumped to vessels in a way similar to a micro-industrial line production process; the vessels with the propellants will be then ready to be taken by astronauts, from a small door outside the LPM. The shape of this spacecraft must be conical in order to not unbalance it during the landing and roving maneuvers and soil cargoes, and it will be shielded externally from heat and radiation from the Sun, and micrometeoroids, to prevent the internal thermal conduction and electronic operations from damaging. A solar array externally deployed can produce 44 KW of electric soil energy for the production process. This miniature chemical-processing plant can possibly have an output of 100 Kg of liquid oxygen and 200 Kg of liquid hydrogen per day. Telecommunications with Earth will provide the onboard computer courses for roving to new mapped areas with richer propellants content in the soil. The spacecraft can weight approximately 6,000 Kg (at launch time from Earth). It will be necessary two LPMs for providing all the liquid oxygen and hydrogen needed to supply spacecrafts next to a semi-permanent small manned lunar base. With the Lunar Propellant Manufacturer it will solve the problem of not-expensively producing great quantities of propellants for a manned spacecraft to explore Mars and beyond In the Solar System.

Solar Wind - Magnetosheath - Magnetopause Interactions in Global Hybrid-Vlasov Simulations

NASA Astrophysics Data System (ADS)

Hoilijoki, S.; Pfau-Kempf, Y.; Ganse, U.; Hietala, H.; Cassak, P.; Walsh, B.; Juusola, L.; Jarvinen, R.; von Alfthan, S.; Palmroth, M.

2017-12-01

We present results of interactions of solar wind and Earth's magnetosphere in global hybrid-Vlasov simulations carried out using the Vlasiator model. Vlasiator propagates ions as velocity distribution functions by solving the Vlasov equation and electrons are treated as charge-neutralizing massless fluid. Vlasiator simulations show a strong coupling between the ion scale and global scale physics. Global scale phenomena affect the local physics and the local phenomena impact the global system. Our results have shown that mirror mode waves growing in the quasi-perpendicular magnetosheath have an impact on the local reconnection rates at the dayside magnetopause. Furthermore, multiple X-line reconnection at the dayside magnetopause leads to the formation of magnetic islands (2D flux transfer events), which launch bow waves upstream propagating through the magnetosheath. These steep bow waves have the ability to accelerate ions in the magnetosheath. When the bow waves reach the bow shock they are able to bulge the shock locally. The bulge in the shock decreases the angle between the interplanetary magnetic field and the shock normal and allows ions to be reflected back to the solar wind along the magnetic field lines. Consequently, Vlasiator simulations show that magnetosheath fluctuations affect magnetopause reconnection and reconnection may influence particle acceleration and reflection in the magnetosheath and solar wind.

Computing the proton aurora at early Mars

NASA Astrophysics Data System (ADS)

Lovato, K.; Gronoff, G.; Curry, S.; Simon Wedlund, C.; Moore, W. B.

2017-12-01

In the early Solar System, ( 4 Gyr ago) our Sun was 70% less luminous than what is seen today but much more active. Indeed, for young stars, solar flares occurs more frequently and therefore so do coronal mass ejections and solar energetic particle events. With an increase in solar events, the flux of protons becomes extremely high, and affects planetary atmosphere in a more extreme way as today. Proton precipitation on planets has an impact on the energy balance of their upper atmospheres, can affect the photochemistry and create auroral emissions. Understanding the protons precipitation at the early Mars can help in understanding occurring chemical process as well as atmospheric evolution and escape. We concentrated our effort on the proton up to a MeV since they have the most important influence on the upper atmosphere. Using scaling laws, we estimated the proton flux for the Early Mars up to a MeV. A kinetic 1D code, validated for the current Mars, was used to compute the effects of the low energy protons precipitation on the Early Mars. This model solves the coupled H+/H multi-stream dissipative transport equation as well as the transport of the secondary electron. For the Early Mars, it allowed to compute the magnitude of the proton Aurora, as well as the corresponding upwards H flux.

Recent developments for realistic solar models

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

Serenelli, Aldo M.

2014-05-02

The 'solar abundance problem' has triggered a renewed interest in revising the concept of SSM from different perspectives: 1) constituent microphysics: equation of state, nuclear rates, radiative opacities; 2) constituent macrophysics: the physical processes impact the evolution of the Sun and its present-day structure, e.g. dynamical processes induced by rotation, presence of magnetic fields; 3) challenge the hypothesis that the young Sun was chemically homogeneous: the possible interaction of the young Sun with its protoplanetary disk. Here, I briefly review and then present a (personal) view on recent advances and developments on solar modeling, part of them carried out asmore » attempts to solve the solar abundance problem.« less

The effects of Q-nuclei on stellar burning

NASA Astrophysics Data System (ADS)

Boyd, R. N.; Turner, R. E.; Sur, B.; Rybarcyk, L.; Joseph, C.

1985-01-01

The effects of anomalous nuclei, Q-nuclei, on stellar burning are examined. The baryon binding energies, beta-decay properties, and thermonuclear reaction rates for the Q-nuclei suggest they could catalyze a cycle in which four protons are combined to form a 4He nucleus. The properties required of the Q-nuclei for them to solve the solar neutrino problem are determined. A solar modelling calculation was performed with Q-nuclei included, and several interesting results therefrom are compared to observations. Finally the solar neutrino detection rates for 71Ga and 115In detectors, in addition to that for 37Cl, are estimated when Q-nuclei are included in the solar burning.

A high efficiency dual-junction solar cell implemented as a nanowire array.

PubMed

Yu, Shuqing; Witzigmann, Bernd

2013-01-14

In this work, we present an innovative design of a dual-junction nanowire array solar cell. Using a dual-diameter nanowire structure, the solar spectrum is separated and absorbed in the core wire and the shell wire with respect to the wavelength. This solar cell provides high optical absorptivity over the entire spectrum due to an electromagnetic concentration effect. Microscopic simulations were performed in a three-dimensional setup, and the optical properties of the structure were evaluated by solving Maxwell's equations. The Shockley-Queisser method was employed to calculate the current-voltage relationship of the dual-junction structure. Proper design of the geometrical and material parameters leads to an efficiency of 39.1%.

One-Dimensional Metal-Oxide Nanostructures for Solar Photocatalytic Water-Splitting

NASA Astrophysics Data System (ADS)

Wang, Fengyun; Song, Longfei; Zhang, Hongchao; Luo, Linqu; Wang, Dong; Tang, Jie

2017-08-01

Because of their unique physical and chemical properties, one-dimensional (1-D) metal-oxide nanostructures have been extensively applied in the areas of gas sensors, electrochromic devices, nanogenerators, and so on. Solar water-splitting has attracted extensive research interest because hydrogen generated from solar-driven water splitting is a clean, sustainable, and abundant energy source that not only solves the energy crisis, but also protects the environment. In this comprehensive review, the main synthesis methods, properties, and especially prominent applications in solar water splitting of 1-D metal-oxides, including titanium dioxide (TiO2), zinc oxide (ZnO), tungsten trioxide (WO3), iron oxide (Fe2O3), and copper oxide (CuO) are fully discussed.

Training a Green Workforce With Stem Initiatives at the Alamo Colleges District

NASA Astrophysics Data System (ADS)

Reyes, R.; Strybos, J.

2017-12-01

The Alamo Colleges District (ACD) includes minority serving institutions successfully incorporating climate science and sustainability-related projects to engage students in STEM courses. This network of five community colleges is based around San Antonio, Texas, and has a student population of approximately 60,000 that reflects the diversity of the community. San Antonio residents are familiar with recent extreme weather conditions, such as extreme droughts and intensified annual rainfalls, and the colleges understand the importance of education about climate science, climate change and sustainable solutions. This presentation will discuss initiatives to engage students in STEMS program while providing them with tools to solve climate change problems at a local level. ACD's innovative tools to train a green workforce is focused on engaging students in courses provided toward accredited certificates and degrees. Example of these courses include Wind Power Generation, Wind Turbine Troubleshooting, Solar Photovoltaics Systems, Wastewater Minimization and Waste Water Treatment. Students have access to a 400-kW PV system installed at the Center for Excellence that is used as a training tool in solar panel installation and maintenance. Also, solar panels on the rooftop of the Scobee Education Center and adjacent bus stops are connected to an eGauge system and used as simulation training about energy and space science. At Eco Centro, students have worked on solar hydroponic projects, the refurbishment of a shipping container for food production in a controlled atmosphere, and the installation of a shipping container home that will be used as a teaching facility about sustainable design and construction. Finally, a recent project to convert an old trailer into a Mobile Weather Station will be used as a STEM classroom to prepare students to understand weather data and its local applicability.

An comprehensive time-distance measurement of deep meridional flow and its temporal variation

NASA Astrophysics Data System (ADS)

Chen, Ruizhu; Zhao, Junwei

2016-10-01

We report our latest results on the Sun's deep solar meridional-flow measurements by time-distance helioseismology technique using 6 years of SDO/HMI Doppler-velocity data. Determination of the meridional flow by time-distance helioseismology depends on a precise measurement of the flow-induced travel-time shifts of acoustic waves traveling in the solar interior. To resolve the weak travel-time-shift signals due to deep meridional flow, we need a high signal-to-noise ratio and a robust removal of the center-to-limb (CtoL) effect, which dominates the travel-time shifts. Here we perform an ultimately comprehensive measurement that tracks acoustic waves between any two points on solar surface. The travel-time shifts are composed of CtoL effect, which is a function of disk-centric distances, and contribution from the flow component parallel to wave traveling direction, which is a function of latitude and orientation. Assuming these two effects are independent, we can derive the CtoL effect and meridional-flow contributions by solving a set of linear equations in a least-square sense. We show the solved CtoL effect and the inversion results for the solar meridional flow, and analyze the annual variation of meridional flow from May 2010 to Apr 2016.

Methods and analysis of factors impact on the efficiency of the photovoltaic generation

NASA Astrophysics Data System (ADS)

Tianze, Li; Xia, Zhang; Chuan, Jiang; Luan, Hou

2011-02-01

First of all, the thesis elaborates two important breakthroughs which happened In the field of the application of solar energy in the 1950s.The 21st century the development of solar photovoltaic power generation will have the following characteristics: the continued high growth of industrial development, the significantly reducing cost of the solar cell, the large-scale high-tech development of photovoltaic industries, the breakthroughs of the film battery technology, the rapid development of solar PV buildings integration and combined to the grids. The paper makes principles of solar cells the theoretical analysis. On the basis, we study the conversion efficiency of solar cells, find the factors impact on the efficiency of the photovoltaic generation, solve solar cell conversion efficiency of technical problems through the development of new technology, and open up new ways to improve the solar cell conversion efficiency. Finally, the paper connecting with the practice establishes policies and legislation to the use of encourage renewable energy, development strategy, basic applied research etc.

A parametric simulation of solar chimney power plant

NASA Astrophysics Data System (ADS)

Beng Hooi, Lim; Kannan Thangavelu, Saravana

2018-01-01

The strong solar radiation, continuous supplies of sunlight and environmental friendly factors have made the solar chimney power plant becoming highly feasible to build in Malaysia. Solar chimney power plant produces upward buoyancy force through the greenhouse effect. Numerical simulation was performed on the model of a solar chimney power plant using the ANSYS Fluent software by applying standard k-epsilon turbulence model and discrete ordinates (DO) radiation model to solve the relevant equations. A parametric study was carried out to evaluate the performance of solar chimney power plant, which focused on the temperature rise in the collector, air velocity at the chimney base, and pressure drop inside the chimney were based on the results of temperature, velocity, and static pressure distributions. The results demonstrate reliability by comparing a model with the experimental data of Manzanares Spanish prototype. Based on the numerical results, power capacity and efficiency were analysed theoretically. Results indicate that a stronger solar radiation and larger prototype will improve the performance of solar chimney power plant.

Science Experiments of a Jupiter Trojan asteroid in the Solar Power Sail Mission

NASA Astrophysics Data System (ADS)

Okada, T.; Kebukawa, Y.; Aoki, J.; Kawai, Y.; Ito, M.; Yano, H.; Okamoto, C.; Matsumoto, J.; Bibring, J. P.; Ulamec, S.; Jaumann, R.; Iwata, T.; Mori, O.; Kawaguchi, J.

2017-12-01

A Jupiter Trojan asteroid mission using a large area solar power sail (SPS) is under study in JAXA in collaboration with DLR and CNES. The asteroid will be investigated through remote sensing, followed by in situ in-depth observations on the asteroid with a lander. A sample-return is also studied as an option. LUCY has been selected as the NASA's future Discovery class mission which aims at understanding the diversity of Jupiter Trojans by multiple flybys, complementally to the SPS mission. The SPS is a candidate of the next medium class space science mission in Japan. The 1.4-ton spacecraft will carry a 100-kg class lander and 20-kg mission payloads on it. Its launch is expected in mid 2020s, and will take at least 11 years to visit a Jupiter Trojan asteroid. During the cruise phase, science experiments will be performed such as an infrared astronomy, a very long baseline gamma ray interferometry, and dust and magnetic field measurements. A classical static model of solar system suggests that the Jupiter Trojans were formed around the Jupiter region, while a dynamical model such as Nice model indicates that they formed at the far end of the solar system and then scattered inward due to a dynamical migration of giant planets. The physical, mineralogical, organics and isotopic distribution in the heliocentric distance could solve their origin and evolution of the solar system. A global mapping of the asteroid from the mothership will be conducted such as high-resolved imaging, NIR and TIR imaging spectrometry, and radar soundings. The lander will characterize the asteroid with geological, mineralogical, and geophysical observations using a panoramic camera, an infrared hyperspectral imager, a magnetometer, and a thermal radiometer. These samples will be measured by a high resolved mass spectrometer (HRMS) to investigate isotopic ratios of hydrogen, nitrogen, oxygen, as well as organic species.

Exact solutions of magnetohydrodynamics for describing different structural disturbances in solar wind

NASA Astrophysics Data System (ADS)

Grib, S. A.; Leora, S. N.

2016-03-01

We use analytical methods of magnetohydrodynamics to describe the behavior of cosmic plasma. This approach makes it possible to describe different structural fields of disturbances in solar wind: shock waves, direction discontinuities, magnetic clouds and magnetic holes, and their interaction with each other and with the Earth's magnetosphere. We note that the wave problems of solar-terrestrial physics can be efficiently solved by the methods designed for solving classical problems of mathematical physics. We find that the generalized Riemann solution particularly simplifies the consideration of secondary waves in the magnetosheath and makes it possible to describe in detail the classical solutions of boundary value problems. We consider the appearance of a fast compression wave in the Earth's magnetosheath, which is reflected from the magnetosphere and can nonlinearly overturn to generate a back shock wave. We propose a new mechanism for the formation of a plateau with protons of increased density and a magnetic field trough in the magnetosheath due to slow secondary shock waves. Most of our findings are confirmed by direct observations conducted on spacecrafts (WIND, ACE, Geotail, Voyager-2, SDO and others).

Gauss-Seidel and Successive Overrelaxation Methods for Radiative Transfer with Partial Frequency Redistribution

NASA Astrophysics Data System (ADS)

Sampoorna, M.; Trujillo Bueno, J.

2010-04-01

The linearly polarized solar limb spectrum that is produced by scattering processes contains a wealth of information on the physical conditions and magnetic fields of the solar outer atmosphere, but the modeling of many of its strongest spectral lines requires solving an involved non-local thermodynamic equilibrium radiative transfer problem accounting for partial redistribution (PRD) effects. Fast radiative transfer methods for the numerical solution of PRD problems are also needed for a proper treatment of hydrogen lines when aiming at realistic time-dependent magnetohydrodynamic simulations of the solar chromosphere. Here we show how the two-level atom PRD problem with and without polarization can be solved accurately and efficiently via the application of highly convergent iterative schemes based on the Gauss-Seidel and successive overrelaxation (SOR) radiative transfer methods that had been previously developed for the complete redistribution case. Of particular interest is the Symmetric SOR method, which allows us to reach the fully converged solution with an order of magnitude of improvement in the total computational time with respect to the Jacobi-based local accelerated lambda iteration method.

On the Voyager 1 Zero Radial Velocity Measurements in the Inner Heliosheath

NASA Astrophysics Data System (ADS)

Pogorelov, N. V.; Borovikov, S. N.; Kryukov, I.; Zank, G. P.

2011-12-01

Theoretical analysis of the Voyager 1 data revealed a very small, or even negative, value of the solar wind (SW) radial velocity component. This should not be surprising if we take into account time-dependent processes that take place in the inner heliosheath (IHS). We analyze solar cycle modeling of the SW interaction with the local interstellar medium (LISM) and demonstrate the existence of small and negative values of the SW radial velocity. It shown that, in reality, a similar picture can be observed in the outer heliosheath (OHS), where on the contrary, extended regions of the positive radial velocity are observed. Another scenario discussed in this talk is related to effects of transients, such as global merged interaction regions and corotating interacting regions. Numerical results are obtained with the SW-LISM interaction model developed in the UAHuntsville and implemented in the Multi-Scale Fluid-Kinetic Simulation Suite. This model treats ions magnetohydrodynamically while the transport of neutral atoms is performed kinetically by solving the Boltzmann equation with a Monte Carlo approach or using a multi-fluid approach developed in mid-90's by G. P. Zank. Pickup ions (PUIs) can be treated as a separate fluid. The evolution of the PUI-generated turbulence is addressed on the differential level by adding three additional equations, which are solved self-consistently with the MHD-kinetic system of equations.

Estimation and experimental evaluation of the shortfall of photovoltaic plants in Tunisia: case study of the use of titled surfaces

NASA Astrophysics Data System (ADS)

Belkilani, Kaouther; Ben Othman, Afef; Besbes, Mongi

2018-02-01

To maximize the production of electrical energy in photovoltaic plants, the best solution is to use sun tracking systems whose panels are permanently exposed to solar radiation to ensure the best angle of inclination. These systems are expensive, their implementation is difficult, and their maintenance is complicated. The fixed inclination of the solar panels is easy to implement but its profitability is minimal. To solve this dilemma, the researchers propose to shift the panel's angle of inclination over predetermined periods. In many countries, weather data measurements are either unavailable or lacking. So to fill this gap, we propose in this paper the development of mathematical models to calculate the best angle of inclination and the period of poise of this angle (month, season or other duration). The theoretical results obtained are validated by experimental tests and are conducted in three regions of Tunisia (North, Center and South). The objective is to determine, for each region, the optimal angle and the duration needed before switching to the next angle depending on the installation of fixed PV panels shortfalls.

Parameter-Study Of The Thermal Yarkovsky Effect Acting On Neas

NASA Astrophysics Data System (ADS)

Polishook, David; Prialnik, D.; Rosenberg, E.; Brosch, N.

2010-10-01

We study the relevant parameters for the thermal Yarkovsky effect acting on Near-Earth Asteroids (NEAs), specifically the rotation period and rotation axis. The study uses a quasi 3-D thermal model to derive the temperature map over the surface of the asteroid, and the thermal thrust is calculated. The model (Prialnik et al. 2004, Rosenberg and Prialnik 2006), uses an implicit scheme to numerically solve the equations that describe the asteroid and its thermal evolution. The results show how the thermal thrust is stronger for fast-rotating asteroids, as heat is emitted from their surface on the evening side, increasing the tangential component of the thermal thrust. Moreover, we show the differences in the thermal thrust between asteroids with different perihelion distances, and how this can explain the observed distribution of asteroids in the inner Solar System on the spin-perihelion plane. Our results suggest that many asteroids within the inner Solar System may have retrograde spins. Acknowledgements: D. Polishook is grateful for an Ilan Ramon doctoral scholarship from the Israeli Ministry of Science.

Theoretcial studies of solar-pumped lasers

NASA Technical Reports Server (NTRS)

Harries, W. L.; Fong, Z. S.

1984-01-01

A method of pumping a COhZ laser by a hot cavity was demonstrated. The cavity, heated by solar radiation, should increase the efficiency of solar pumped lasers used for energy conversion. Kinetic modeling is used to examine the behavior of such a COhZ laser. The kinetic equations are solved numerically vs. time and, in addition, steady state solutions are obtained analytically. The effect of gas heating filling the lower laser level is included. The output power and laser efficiency are obtained as functions of black body temperature and gas ratios (COhZ-He-Ar) and pressures. The values are compared with experimental results.

Thermally Driven One-Fluid Electron-Proton Solar Wind: Eight-Moment Approximation

NASA Astrophysics Data System (ADS)

Olsen, Espen Lyngdal; Leer, Egil

1996-05-01

In an effort to improve the "classical" solar wind model, we study an eight-moment approximation hydrodynamic solar wind model, in which the full conservation equation for the heat conductive flux is solved together with the conservation equations for mass, momentum, and energy. We consider two different cases: In one model the energy flux needed to drive the solar wind is supplied as heat flux from a hot coronal base, where both the density and temperature are specified. In the other model, the corona is heated. In that model, the coronal base density and temperature are also specified, but the temperature increases outward from the coronal base due to a specified energy flux that is dissipated in the corona. The eight-moment approximation solutions are compared with the results from a "classical" solar wind model in which the collision-dominated gas expression for the heat conductive flux is used. It is shown that the "classical" expression for the heat conductive flux is generally not valid in the solar wind. In collisionless regions of the flow, the eight-moment approximation gives a larger thermalization of the heat conductive flux than the models using the collision-dominated gas approximation for the heat flux, but the heat flux is still larger than the "saturation heat flux." This leads to a breakdown of the electron distribution function, which turns negative in the collisionless region of the flow. By increasing the interaction between the electrons, the heat flux is reduced, and a reasonable shape is obtained on the distribution function. By solving the full set of equations consistent with the eight-moment distribution function for the electrons, we are thus able to draw inferences about the validity of the eight-moment description of the solar wind as well as the validity of the very commonly used collision-dominated gas approximation for the heat conductive flux in the solar wind.

Comparative Studies to Be a Theme for the Joint Assembly in Montreal

NASA Astrophysics Data System (ADS)

Mendillo, Michael; Schubert, Gerald; Alexander, Joan; Strangeway, Robert

2004-02-01

To have a truly global view of geophysical systems, it helps to have a few globes to view. Our solar system offers a rich set of case studies on how environmental systems form and evolve. The temperature structures of atmospheres, their circulation patterns, and their optical emissions are governed by the same basic laws of physics and photochemistry, but with constituents and solar flux input values that vary dramatically over the span of the planets. The escape of gases from the Earth and those planets and moons with dense atmospheres involve processes rather different from those associated with sputtered gases from the far more abundant regoliths of rock and ice. The origins and dynamics of plasmas and magnetic fields, their interactions with the flowing solar wind and/or rapidly rotating planetary fields, and episodic ``space weather'' events provide additional areas of common science in remarkably different settings. The Earth and its companions thus comprise the only known set of experiments in planetary formation for which there is actual data to validate and to challenge theory and computer models. While observations are abundant for Earth, and beyond the ``discovery mode'' set for many of the planets and moons, there remain crucial gaps in our understanding and formidable problems to solve at each of these worlds. Coupling processes, perhaps most of all, from regions below and above the environmental systems being studied are at the forefront of current work, drawing attention to the need for advanced observational capabilities and breakthroughs in computer simulation techniques.

Helioseismology: A probe of the solar interior, atmosphere, and activity cycle

NASA Technical Reports Server (NTRS)

Rhodes, E. J., Jr.

1995-01-01

Helioseismology began in earnest in the mid 1970's. In the two decades which have elapsed since that time this branch of solar physics has become a mature field of research. Helioseismology has demonstrated that the solar convection zone is about twice as deep as was generally thought to be the case before 1977. Helioseismology has also provided measurements of the solar internal angular velocity over much of the sun's interior. Helioseismology has also ruled out models which would solve the solar neutrino problem by a lowering of the temperature of the core. Recently, some of the seismic properties of the sun have been demonstrated to vary with changing levels of solar activity. Also, helioseismology has recently provided evidence for helical flow patterns in the shallow, sub-photosphere layers. The techniques of helioseismology are also expanding to include seismic probes of solar active regions. Some work is also being conducted into the possible contributions of the solar acoustic models to the heating of the solar atmosphere. In this talk I will highlight a few of the above results and concentrate on current areas of research in the field.

Innovative paths for providing green energy for sustainable global economic growth

NASA Astrophysics Data System (ADS)

Singh, Rajendra; Alapatt, G. F.

2012-10-01

According to United Nation, world population may reach 10.1 billion by the year 2100. The fossil fuel based global economy is not sustainable. For sustainable global green energy scenario we must consider free fuel based energy conversion, environmental concerns and conservation of water. Photovoltaics (PV) offers a unique opportunity to solve the 21st century's electricity generation because solar energy is essentially unlimited and PV systems provide electricity without any undesirable impact on the environment. Innovative paths for green energy conversion and storage are proposed in areas of R and D, manufacturing and system integration, energy policy and financing. With existing silicon PV system manufacturing, the implementation of new innovative energy policies and new innovative business model can provide immediately large capacity of electricity generation to developed, emerging and underdeveloped economies.

Japanese Exploration to Solar System Small Bodies: Rewriting a Planetary Formation Theory with Astromaterial Connection (Invited)

NASA Astrophysics Data System (ADS)

Yano, H.

2013-12-01

Three decades ago, Japan's deep space exploration started with Sakigake and Suisei, twin flyby probes to P/Halley. Since then, the Solar System small bodies have been one of focused destinations to the Japanese solar system studies even today. Only one year after the Halley armada launch, the very first meeting was held for an asteroid sample return mission at ISAS, which after 25 years, materialized as the successful Earth return of Hayabusa , an engineering verification mission for sample return from surfaces of an NEO for the first time in the history. Launched in 2003 and returned in 2010, Hayabusa became the first to visit a sub-km, rubble-pile potentially hazardous asteroid in near Earth space. Its returned samples solved S-type asteroid - ordinary chondrite paradox by proving space weathering evidences in sub-micron scale. Between the Halley missions and Hayabusa, SOCCER concept by M-V rocket was jointly studied between ISAS and NASA; yet it was not realized due to insufficient delta-V for intact capture by decelerating flyby/encounter velocity to a cometary coma. The SOCCER later became reality as Stardust, NASA Discovery mission for cometary coma dust sample return in1999-2006. Japan has collected the second largest collection of the Antarctic meteorites and micrometeorites of the world and asteromaterial scientists are eager to collaborate with space missions. Also Japan enjoyed a long history of collaborations between professional astronomers and high-end amateur observers in the area of observational studies of asteroids, comets and meteors. Having these academic foundations, Japan has an emphasis on programmatic approach to sample returns of Solar System small bodies in future prospects. The immediate follow-on to Hayabusa is Hayabusa-2 mission to sample return with an artificial impactor from 1999 JU3, a C-type NEO in 2014-2020. Following successful demonstration of deep space solar sail technique by IKAROS in 2010-2013, the solar power sail is a deep space probe with hybrid propulsion of solar photon sail and ion engine system that will enable Japan to reach out deep interplanetary space beyond the main asteroid belt. Since 2002, Japanese scientists and engineers have been investigating the solar power sail mission to Jupiter Trojans and interdisciplinary cruising science, such as infrared observation of zodiacal light due to cosmic dust, which at the same time hit a large cross section of the solar sail membrane dust detector, concentrating inside the main asteroid belt. Now the mission design has extended from cruising and fly-by only to rendezvous and sample return options from Jupiter Trojan asteroids. Major scientific goal of Jupiter Trojan exploration is to constrain its origin between two competing hypothesis such as remnants of building blocks the Jovian system as the classic model and the second generation captured EKBOs as the planetary migration models, in which several theories are in deep discussion. Also important is to better understand mixing process of material and structure of the early Solar System just beyond snow line. The current plan involves its launch and both solar photon and IES accelerations combined with Earth and Jupiter gravity assists in 2020's, detailed rendezvous investigation of a few 10-km sized D-type asteroid among Jupiter Trojans in early 2030's and an optional sample return of its surface materials to the Earth in late 2030's.

Derivation of Heliophysical Scientific Data from Amateur Observations of Solar Eclipses

NASA Astrophysics Data System (ADS)

Stoev, A. D.; Stoeva, P. V.

2006-03-01

The basic scientific aims and observational experiments included in the complex observational program - Total Solar Eclipse '99 - are described in the work. Results from teaching and training students of total solar eclipse (TSE) observation in the Public Astronomical Observatory (PAO) in Stara Zagora and their selection for participation in different observational teams are also discussed. During the final stage, a special system of methods for investigation of the level of pretensions (the level of ambition as to what he/she feels capable of achieving in the context of problem solving/observation) of the students is applied. Results obtained from the observational experiments are interpreted mainly in the following themes: Investigation of the structure of the white-light solar corona and evolution of separate coronal elements during the total phase of the eclipse; Photometry of the white-light solar corona and specific emission lines; Meteorological, actinometrical and optical atmospheric investigations; Astrometry of the Moon during the phase evolution of the eclipse; Biological and behavioral reactions of highly organized colonies (ants and bats) during the eclipse. It is also shown that data processing, observational results and their interpretation, presentation and publishing in specialized and amateur editions is a peak in the independent creative activity of students and amateur astronomers. This enables students from the Astronomy schools at Public Astronomical Observatories and Planetariums (PAOP) to develop creative skills, emotional - volitional personal qualities, orientation towards scientific work, observations and experiments, and build an effective scientific style of thinking.

Low Energy Transfer to the Moon

NASA Astrophysics Data System (ADS)

Koon, W. S.; Lo, M. W.; Marsden, J. E.; Ross, S. D.

2001-11-01

New space missions are increasingly more complex; demand for exotic orbits to solve engineering problems has grown beyond the existing astrodynamic infrastructure based on two-body interactions. The delicate heteroclinic dynamics used by the Genesis Mission dramatically illustrate the need for a new paradigm: dynamical system study of three-body problem. Furthermore, this dynamics has much to say about the morphology and transport of materials within the Solar System. The cross-fertilization of ideas between the natural dynamics of the Solar System and applications to engineering has produced new techniques for constructing spacecraft trajectories with interesting characteristics. Specifically, these techniques are used here to produce a lunar capture mission which uses less fuel than a Hohmann transfer. We approximate the Sun-Earth-Moon-Spacecraft four-body problem as two three-body problems. Using the invariant manifold structures of the Lagrange points of the three-body systems, we are able to construct low energy transfer trajectories from the Earth which exhibit ballistic capture at the Moon. The techniques used in the design and construction of this trajectory may be applied in many situations. This is joint work with Martin W. Lo, Jerrold E. Marsden and Shane D. Ross and was partially supported by the National Science Foundation Grant No. KFI/ATM-9873133 under a contract with the Jet Propulsion Laboratory, NASA.

Parker Solar Probe: A NASA Mission to Touch the Sun: Mission Status Update

NASA Astrophysics Data System (ADS)

Fox, N. J.

2017-12-01

The newly renamed, Parker Solar Probe (PSP) mission will be the first mission to fly into the low solar corona, revealing how the corona is heated and the solar wind and energetic particles are accelerated, solving fundamental mysteries that have been top priority science goals since such a mission was first proposed in 1958. The scale and concept of such a mission has been revised at intervals since that time, yet the core has always been a close encounter with the Sun. The primary science goal of the Parker Solar Probe mission is to determine the structure and dynamics of the Sun's coronal magnetic field, understand how the solar corona and wind are heated and accelerated, and determine what mechanisms accelerate and transport energetic particles. PSP uses an innovative mission design, significant technology development and a risk-reducing engineering development to meet the science objectives. In this presentation, we provide an update on the progress of the Parker Solar Probe mission as we prepare for the July 2018 launch.

Solar Probe Plus: A NASA Mission to Touch the SunMission Status Update

NASA Astrophysics Data System (ADS)

Fox, N. J.

2016-12-01

Solar Probe Plus (SPP), currently in Phase D, will be the first mission to fly into the low solar corona, revealing how the corona is heated and the solar wind and energetic particles are accelerated, solving fundamental mysteries that have been top priority science goals since such a mission was first proposed in 1958. The scale and concept of such a mission has been revised at intervals since that time, yet the core has always been a close encounter with the Sun. The primary science goal of the Solar Probe Plus mission is to determine the structure and dynamics of the Sun's coronal magnetic field, understand how the solar corona and wind are heated and accelerated, and determine what mechanisms accelerate and transport energetic particles. SPP uses an innovative mission design, significant technology development and a risk-reducing engineering development to meet the SPP science objectives. In this presentation, we provide an update on the progress of the Solar Probe Plus mission as we prepare for the July 2018 launch.

Simulation of the real efficiencies of high-efficiency silicon solar cells

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

Sachenko, A. V., E-mail: sach@isp.kiev.ua; Skrebtii, A. I.; Korkishko, R. M.

The temperature dependences of the efficiency η of high-efficiency solar cells based on silicon are calculated. It is shown that the temperature coefficient of decreasing η with increasing temperature decreases as the surface recombination rate decreases. The photoconversion efficiency of high-efficiency silicon-based solar cells operating under natural (field) conditions is simulated. Their operating temperature is determined self-consistently by simultaneously solving the photocurrent, photovoltage, and energy-balance equations. Radiative and convective cooling mechanisms are taken into account. It is shown that the operating temperature of solar cells is higher than the ambient temperature even at very high convection coefficients (~300 W/m{sup 2}more » K). Accordingly, the photoconversion efficiency in this case is lower than when the temperature of the solar cells is equal to the ambient temperature. The calculated dependences for the open-circuit voltage and the photoconversion efficiency of high-quality silicon solar cells under concentrated illumination are discussed taking into account the actual temperature of the solar cells.« less

On the evaporation of solar dark matter: spin-independent effective operators

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

Liang, Zheng-Liang; Wu, Yue-Liang; Yang, Zi-Qing

2016-09-13

As a part of the effort to investigate the implications of dark matter (DM)-nucleon effective interactions on the solar DM detection, in this paper we focus on the evaporation of the solar DM for a set of the DM-nucleon spin-independent (SI) effective operators. In order to put the evaluation of the evaporation rate on a more reliable ground, we calculate the non-thermal distribution of the solar DM using the Monte Carlo methods, rather than adopting the Maxwellian approximation. We then specify relevant signal parameter spaces for the solar DM detection for various SI effective operators. Based on the analysis, wemore » determine the minimum DM masses for which the DM-nucleon coupling strengths can be probed from the solar neutrino observations. As an interesting application, our investigation also shows that evaporation effect can not be neglectd in a recent proposal aiming to solve the solar abundance problem by invoking the momentum-dependent asymmetric DM in the Sun.« less

Numerical study on the effects of absorptivity on performance of flat plate solar collector of a water heater

NASA Astrophysics Data System (ADS)

Tambunan, D. R. S.; Sibagariang, Y. P.; Ambarita, H.; Napitupulu, F. H.; Kawai, H.

2018-03-01

The characteristics of absorber plate of a flat plate solar collector play an important role in the improvement of the performance. In this work, a numerical analysis is carried out to explore the effect of absorptivity and emissivity of absorber plate to the performance of the solar collector of a solar water heater. For a results comparison, a simple a simple solar box cooker with absorber area of 0.835 m × 0.835 m is designed and fabricated. It is employed to heat water in a container by exposing to the solar radiation in Medan city of Indonesia. The transient governing equations are developed. The governing equations are discretized and solved using the forward time step marching technique. The results reveal that the experimental and numerical results show good agreement. The absorptivity of the plate absorber and emissivity of the glass cover strongly affect the performance of the solar collector.

Solar hydrogen and solar electricity using mesoporous materials

NASA Astrophysics Data System (ADS)

Mahoney, Luther

The development of cost-effective materials for effective utilization of solar energy is a major challenge for solving the energy problems that face the world. This thesis work relates to the development of mesoporous materials for solar energy applications in the areas of photocatalytic water splitting and the generation of electricity. Mesoporous materials were employed throughout the studies because of their favorable physico-chemical properties such as high surface areas and large porosities. The first project was related to the use of a cubic periodic mesoporous material, MCM-48. The studies showed that chromium loading directly affected the phase of mesoporous silica formed. Furthermore, within the cubic MCM-48 structure, the loading of polychromate species determined the concentration of solar hydrogen produced. In an effort to determine the potential of mesoporous materials, titanium dioxide was prepared using the Evaporation-Induced Self-Assembly (EISA) synthetic method. The aging period directly determined the amount of various phases of titanium dioxide. This method was extended for the preparation of cobalt doped titanium dioxide for solar simulated hydrogen evolution. In another study, metal doped systems were synthesized using the EISA procedure and rhodamine B (RhB) dye sensitized and metal doped titania mesoporous materials were evaluated for visible light hydrogen evolution. The final study employed various mesoporous titanium dioxide materials for N719 dye sensitized solar cell (DSSC) materials for photovoltaic applications. The materials were extensively characterized using powder X-ray diffraction (XRD), nitrogen physisorption, diffuse reflectance spectroscopy (DRS), UV-Vis spectroscopy, Fourier-Transform-Infrared Spectroscopy (FT-IR), Raman spectroscopy, chemisorption, photoluminescence (PL), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). In addition, photoelectrochemical measurements were completed using current-voltage (I-V) curves, external quantum efficiency (EQE) curves, electrochemical impedance spectroscopy (EIS), and transient spectroscopy. The thesis work presented provides a better understanding of the role of mesoporous materials for solar hydrogen and solar electricity production.

PROM7: 1D modeler of solar filaments or prominences

NASA Astrophysics Data System (ADS)

Gouttebroze, P.

2018-05-01

PROM7 is an update of PROM4 (ascl:1306.004) and computes simple models of solar prominences and filaments using Partial Radiative Distribution (PRD). The models consist of plane-parallel slabs standing vertically above the solar surface. Each model is defined by 5 parameters: temperature, density, geometrical thickness, microturbulent velocity and height above the solar surface. It solves the equations of radiative transfer, statistical equilibrium, ionization and pressure equilibria, and computes electron and hydrogen level population and hydrogen line profiles. Moreover, the code treats calcium atom which is reduced to 3 ionization states (Ca I, Ca II, CA III). Ca II ion has 5 levels which are useful for computing 2 resonance lines (H and K) and infrared triplet (to 8500 A).

The Evolution of the Solar Magnetic Field: A Comparative Analysis of Two Models

NASA Astrophysics Data System (ADS)

McMichael, K. D.; Karak, B. B.; Upton, L.; Miesch, M. S.; Vierkens, O.

2017-12-01

Understanding the complexity of the solar magnetic cycle is a task that has plagued scientists for decades. However, with the help of computer simulations, we have begun to gain more insight into possible solutions to the plethora of questions inside the Sun. STABLE (Surface Transport and Babcock Leighton) is a newly developed 3D dynamo model that can reproduce features of the solar cycle. In this model, the tilted bipolar sunspots are formed on the surface (based on the toroidal field at the bottom of the convection zone) and then decay and disperse, producing the poloidal field. Since STABLE is a 3D model, it is able to solve the full induction equation in the entirety of the solar convection zone as well as incorporate many free parameters (such as spot depth and turbulent diffusion) which are difficult to observe. In an attempt to constrain some of these free parameters, we compare STABLE to a surface flux transport model called AFT (Advective Flux Transport) which solves the radial component of the magnetic field on the solar surface. AFT is a state-of-the-art surface flux transport model that has a proven record of being able to reproduce solar observations with great accuracy. In this project, we implement synthetic bipolar sunspots into both models, using identical surface parameters, and run the models for comparison. We demonstrate that the 3D structure of the sunspots in the interior and the vertical diffusion of the sunspot magnetic field play an important role in establishing the surface magnetic field in STABLE. We found that when a sufficient amount of downward magnetic pumping is included in STABLE, the surface magnetic field from this model becomes insensitive to the internal structure of the sunspot and more consistent with that of AFT.

Extreme ultraviolet spectral irradiance measurements since 1946

NASA Astrophysics Data System (ADS)

Schmidtke, G.

2015-03-01

In the physics of the upper atmosphere the solar extreme ultraviolet (EUV) radiation plays a dominant role controlling most of the thermospheric/ionospheric (T/I) processes. Since this part of the solar spectrum is absorbed in the thermosphere, platforms to measure the EUV fluxes became only available with the development of rockets reaching altitude levels exceeding 80 km. With the availability of V2 rockets used in space research, recording of EUV spectra started in 1946 using photographic films. The development of pointing devices to accurately orient the spectrographs toward the sun initiated intense activities in solar-terrestrial research. The application of photoelectric recording technology enabled the scientists placing EUV spectrometers aboard satellites observing qualitatively strong variability of the solar EUV irradiance on short-, medium-, and long-term scales. However, as more measurements were performed more radiometric EUV data diverged due to the inherent degradation of the EUV instruments with time. Also, continuous recording of the EUV energy input to the T/I system was not achieved. It is only at the end of the last century that there was progress made in solving the serious problem of degradation enabling to monitore solar EUV fluxes with sufficient radiometric accuracy. The data sets available allow composing the data available to the first set of EUV data covering a period of 11 years for the first time. Based on the sophisticated instrumentation verified in space, future EUV measurements of the solar spectral irradiance (SSI) are promising accuracy levels of about 5% and less. With added low-cost equipment, real-time measurements will allow providing data needed in ionospheric modeling, e.g., for correcting propagation delays of navigation signals from space to earth. Adding EUV airglow and auroral emission monitoring by airglow cameras, the impact of space weather on the terrestrial T/I system can be studied with a spectral terrestrial irradiance camera (STI-Cam) and also be used investigating real-time space weather effects and deriving more detailed correction procedures for the evaluation of Global Navigation Satellite System (GNSS) signals. Progress in physics goes with achieving higher accuracy in measurements. This review historically guides the reader on the ways of exploring the impact of the variable solar radiation in the extreme ultraviolet spectral region on our upper atmosphere in the altitude regime from 80 to 1000 km.

Parabolic solar cooker: Cooking with heat pipe vs direct spiral copper tubes

NASA Astrophysics Data System (ADS)

Craig, Omotoyosi O.; Dobson, Robert T.

2016-05-01

Cooking with solar energy has been seen by many researchers as a solution to the challenges of poverty and hunger in the world. This is no exception in Africa, as solar coking is viewed as an avenue to eliminate the problem of food insecurity, insufficient energy supply for household and industrial cooking. There are several types of solar cookers that have been manufactured and highlighted in literature. The parabolic types of solar cookers are known to reach higher temperatures and therefore cook faster. These cookers are currently being developed for indoor cooking. This technology has however suffered low cooking efficiency and thus leads to underutilization of the high heat energy captured from the sun in the cooking. This has made parabolic solar cookers unable to compete with other conventional types of cookers. Several methods to maximize heat from the sun for indirect cooking has been developed, and the need to improve on them of utmost urgency. This paper investigates how to optimize the heat collected from the concentrating types of cookers by proposing and comparing two types of cooking sections: the spiral hot plate copper tube and the heat pipe plate. The system uses the concentrating solar parabolic dish technology to focus the sun on a conical cavity of copper tubes and the heat is stored inside an insulated tank which acts both as storage and cooking plate. The use of heat pipes to transfer heat between the oil storage and the cooking pot was compared to the use of a direct natural syphon principle which is achieved using copper tubes in spiral form like electric stove. An accurate theoretical analysis for the heat pipe cooker was achieved by solving the boiling and vaporization in the evaporator side and then balancing it with the condensation and liquid-vapour interaction in the condenser part while correct heat transfer, pressure and height balancing was calculated in the second experiment. The results show and compare the cooking time, boiling characteristics, overall utilisation efficiencies and necessary comparison between the two system and other existing systems. AIP Proceedings article template has many predefined paragraph styles for you to use/apply as you write your paper. To format your abstract, use the Microsoft Word template style.

Optimal site selection for sitting a solar park using multi-criteria decision analysis and geographical information systems

NASA Astrophysics Data System (ADS)

Georgiou, Andreas; Skarlatos, Dimitrios

2016-07-01

Among the renewable power sources, solar power is rapidly becoming popular because it is inexhaustible, clean, and dependable. It has also become more efficient since the power conversion efficiency of photovoltaic solar cells has increased. Following these trends, solar power will become more affordable in years to come and considerable investments are to be expected. Despite the size of solar plants, the sitting procedure is a crucial factor for their efficiency and financial viability. Many aspects influence such a decision: legal, environmental, technical, and financial to name a few. This paper describes a general integrated framework to evaluate land suitability for the optimal placement of photovoltaic solar power plants, which is based on a combination of a geographic information system (GIS), remote sensing techniques, and multi-criteria decision-making methods. An application of the proposed framework for the Limassol district in Cyprus is further illustrated. The combination of a GIS and multi-criteria methods produces an excellent analysis tool that creates an extensive database of spatial and non-spatial data, which will be used to simplify problems as well as solve and promote the use of multiple criteria. A set of environmental, economic, social, and technical constrains, based on recent Cypriot legislation, European's Union policies, and expert advice, identifies the potential sites for solar park installation. The pairwise comparison method in the context of the analytic hierarchy process (AHP) is applied to estimate the criteria weights in order to establish their relative importance in site evaluation. In addition, four different methods to combine information layers and check their sensitivity were used. The first considered all the criteria as being equally important and assigned them equal weight, whereas the others grouped the criteria and graded them according to their objective perceived importance. The overall suitability of the study region for sitting solar parks is appraised through the summation rule. Strict application of the framework depicts 3.0 % of the study region scoring a best-suitability index for solar resource exploitation, hence minimizing the risk in a potential investment. However, using different weighting schemes for criteria, suitable areas may reach up to 83 % of the study region. The suggested methodological framework applied can be easily utilized by potential investors and renewable energy developers, through a front end web-based application with proper GUI for personalized weighting schemes.

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.

Numerical Methods of Computational Electromagnetics for Complex Inhomogeneous Systems

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

Cai, Wei

Understanding electromagnetic phenomena is the key in many scientific investigation and engineering designs such as solar cell designs, studying biological ion channels for diseases, and creating clean fusion energies, among other things. The objectives of the project are to develop high order numerical methods to simulate evanescent electromagnetic waves occurring in plasmon solar cells and biological ion-channels, where local field enhancement within random media in the former and long range electrostatic interactions in the latter are of major challenges for accurate and efficient numerical computations. We have accomplished these objectives by developing high order numerical methods for solving Maxwell equationsmore » such as high order finite element basis for discontinuous Galerkin methods, well-conditioned Nedelec edge element method, divergence free finite element basis for MHD, and fast integral equation methods for layered media. These methods can be used to model the complex local field enhancement in plasmon solar cells. On the other hand, to treat long range electrostatic interaction in ion channels, we have developed image charge based method for a hybrid model in combining atomistic electrostatics and continuum Poisson-Boltzmann electrostatics. Such a hybrid model will speed up the molecular dynamics simulation of transport in biological ion-channels.« less

Natural Aggregation Approach based Home Energy Manage System with User Satisfaction Modelling

NASA Astrophysics Data System (ADS)

Luo, F. J.; Ranzi, G.; Dong, Z. Y.; Murata, J.

2017-07-01

With the prevalence of advanced sensing and two-way communication technologies, Home Energy Management System (HEMS) has attracted lots of attentions in recent years. This paper proposes a HEMS that optimally schedules the controllable Residential Energy Resources (RERs) in a Time-of-Use (TOU) pricing and high solar power penetrated environment. The HEMS aims to minimize the overall operational cost of the home, and the user’s satisfactions and requirements on the operation of different household appliances are modelled and considered in the HEMS. Further, a new biological self-aggregation intelligence based optimization technique previously proposed by the authors, i.e., Natural Aggregation Algorithm (NAA), is applied to solve the proposed HEMS optimization model. Simulations are conducted to validate the proposed method.

Seeking Space Aliens and the Strong Approximation Property: A (disjoint) Study in Dust Plumes on Planetary Satellites and Nonsymmetric Algebraic Multigrid

NASA Astrophysics Data System (ADS)

Southworth, Benjamin Scott

PART I: One of the most fascinating questions to humans has long been whether life exists outside of our planet. To our knowledge, water is a fundamental building block of life, which makes liquid water on other bodies in the universe a topic of great interest. In fact, there are large bodies of water right here in our solar system, underneath the icy crust of moons around Saturn and Jupiter. The NASA-ESA Cassini Mission spent two decades studying the Saturnian system. One of the many exciting discoveries was a "plume" on the south pole of Enceladus, emitting hundreds of kg/s of water vapor and frozen water-ice particles from Enceladus' subsurface ocean. It has since been determined that Enceladus likely has a global liquid water ocean separating its rocky core from icy surface, with conditions that are relatively favorable to support life. The plume is of particular interest because it gives direct access to ocean particles from space, by flying through the plume. Recently, evidence has been found for similar geological activity occurring on Jupiter's moon Europa, long considered one of the most likely candidate bodies to support life in our solar system. Here, a model for plume-particle dynamics is developed based on studies of the Enceladus plume and data from the Cassini Cosmic Dust Analyzer. A C++, OpenMP/MPI parallel software package is then built to run large scale simulations of dust plumes on planetary satellites. In the case of Enceladus, data from simulations and the Cassini mission provide insight into the structure of emissions on the surface, the total mass production of the plume, and the distribution of particles being emitted. Each of these are fundamental to understanding the plume and, for Europa and Enceladus, simulation data provide important results for the planning of future missions to these icy moons. In particular, this work has contributed to the Europa Clipper mission and proposed Enceladus Life Finder. PART II: Solving large, sparse linear systems arises often in the modeling of biological and physical phenomenon, data analysis through graphs and networks, and other scientific applications. This work focuses primarily on linear systems resulting from the discretization of partial differential equations (PDEs). Because solving linear systems is the bottleneck of many large simulation codes, there is a rich field of research in developing "fast" solvers, with the ultimate goal being a method that solves an n x n linear system in O(n) operations. One of the most effective classes of solvers is algebraic multigrid (AMG), which is a multilevel iterative method based on projecting the problem into progressively smaller spaces, and scales like O(n) or O(nlog n) for certain classes of problems. The field of AMG is well-developed for symmetric positive definite matrices, and is typically most effective on linear systems resulting from the discretization of scalar elliptic PDEs, such as the heat equation. Systems of PDEs can add additional difficulties, but the underlying linear algebraic theory is consistent and, in many cases, an elliptic system of PDEs can be handled well by AMG with appropriate modifications of the solver. Solving general, nonsymmetric linear systems remains the wild west of AMG (and other fast solvers), lacking significant results in convergence theory as well as robust methods. Here, we develop new theoretical motivation and practical variations of AMG to solve nonsymmetric linear systems, often resulting from the discretization of hyperbolic PDEs. In particular, multilevel convergence of AMG for nonsymmetric systems is proven for the first time. A new nonsymmetric AMG solver is also developed based on an approximate ideal restriction, referred to as AIR, which is able to solve advection-dominated, hyperbolic-type problems that are outside the scope of existing AMG solvers and other fast iterative methods. AIR demonstrates scalable convergence on unstructured meshes, in multiple dimensions, and with high-order finite elements, expanding the applicability of AMG to a new class of problems.

Radiation heat transfer simulation in a window for a small particle solar receiver using the Monte Carlo method

NASA Astrophysics Data System (ADS)

Whitmore, Alexander Jason

Concentrating solar power systems are currently the predominant solar power technology for generating electricity at the utility scale. The central receiver system, which is a concentrating solar power system, uses a field of mirrors to concentrate solar radiation onto a receiver where a working fluid is heated to drive a turbine. Current central receiver systems operate on a Rankine cycle, which has a large demand for cooling water. This demand for water presents a challenge for the current central receiver systems as the ideal locations for solar power plants have arid climates. An alternative to the current receiver technology is the small particle receiver. The small particle receiver has the potential to produce working fluid temperatures suitable for use in a Brayton cycle which can be more efficient when pressurized to 0.5 MPa. Using a fused quartz window allows solar energy into the receiver while maintaining a pressurized small particle receiver. In this thesis, a detailed numerical investigation for a spectral, three dimensional, cylindrical glass window for a small particle receiver was performed. The window is 1.7 meters in diameter and 0.0254 meters thick. There are three Monte Carlo Ray Trace codes used within this research. The first MCRT code, MIRVAL, was developed by Sandia National Laboratory and modified by a fellow San Diego State University colleague Murat Mecit. This code produces the solar rays on the exterior surface of the window. The second MCRT code was developed by Steve Ruther and Pablo Del Campo. This code models the small particle receiver, which creates the infrared spectral direction flux on the interior surface of the window used in this work. The third MCRT, developed for this work, is used to model radiation heat transfer within the window itself and is coupled to an energy equation solver to produce a temperature distribution. The MCRT program provides a source term to the energy equation. This in turn, produces a new temperature field for the MCRT program; together the equations are solved iteratively. These iterations repeat until convergence is reached for a steady state temperature field. The energy equation was solved using a finite volume method. The window's thermal conductivity is modeled as a function of temperature. This thermal model is used to investigate the effects of different materials, receiver geometries, interior convection coefficients and exterior convection coefficients. To prevent devitrification and the ultimate failure of the window, the window needs to stay below the devitrification temperature of the material. In addition, the temperature gradients within the window need to be kept to a minimum to prevent thermal stresses. A San Diego State University colleague E-Fann Saung uses these temperature maps to insure that the mounting of the window does not produce thermal stresses which can cause cracking in the brittle fused quartz. The simulations in this thesis show that window temperatures are below the devitrification temperature of the window when there are cooling jets on both surfaces of the window. Natural convection on the exterior window surface was explored and it does not provide adequate cooling; therefore forced convection is required. Due to the low thermal conductivity of the window, the edge mounting thermal boundary condition has little effect on the maximum temperature of the window. The simulations also showed that the solar input flux absorbed less than 1% of the incoming radiation while the window absorbed closer to 20% of the infrared radiation emitted by the receiver. The main source of absorbed power in the window is located directly on the interior surface of the window where the infrared radiation is absorbed. The geometry of the receiver has a large impact on the amount of emitted power which reached the interior surface of the window, and using a conical shaped receiver dramatically reduced the receiver's infrared flux on the window. The importance of internal emission is explored within this research. Internal emission produces a more even emission field throughout the receiver than applying radiation surface emission only. Due to a majority of the infrared receiver re-radiation being absorbed right at the interior surface, the surface emission only approximation method produces lower maximum temperatures.

Rapid Information and Communication Technology Assessment Team (RTAT): Enabling the Hands and Feet to Win the Hearts and Minds

DTIC Science & Technology

2014-09-01

and 20 “live” tweets were injected into the scenario itself  1 alternative power demonstration ( wind and solar) accomplished  7 remote wireless ...solved this issue. 2. Hastily Formed Networks (HFN)  Alternative power sources were set up:RENEWS–a wind turbine , flexible solar panels, rigid...297 WORKS CONSULTED Akyildiz, I. (2011). Sensor networks in challenged environments. Wireless Technologies for Humanitarian Relief, 3(3).doi

FIESTA ROC: A new finite element analysis program for solar cell simulation

NASA Technical Reports Server (NTRS)

Clark, Ralph O.

1991-01-01

The Finite Element Semiconductor Three-dimensional Analyzer by Ralph O. Clark (FIESTA ROC) is a computational tool for investigating in detail the performance of arbitrary solar cell structures. As its name indicates, it uses the finite element technique to solve the fundamental semiconductor equations in the cell. It may be used for predicting the performance (thereby dictating the design parameters) of a proposed cell or for investigating the limiting factors in an established design.

Metal-dielectric frequency-selective surface for high performance solar window coatings

NASA Astrophysics Data System (ADS)

Toor, Fatima; Guneratne, Ananda C.; Temchenko, Marina

2016-03-01

We demonstrate a solar control window film consisting of metallic nanoantennas designed to reflect infrared (IR) light while allowing visible light to pass through. The film consists of a capacitive frequency-selective surface (CFSS) which acts as a band-stop filter, reflecting only light at target wavelengths. The designed CFSS when installed on windows will lower air conditioning costs by reflecting undesired wavelengths of light and thus reduce the amount of heat that enters a building. State-of-the-art commercial solar control films consist of a multilayer stack which is costly ( 13/m2 to 40/m2) to manufacture and absorbs IR radiation, causing delamination or glass breakage when attached to windows. Our solar control film consists of a nanostructured metallic layer on a polyethylene terephthalate (PET) substrate that reflects IR radiation instead of absorbing it, solving the delamination problem. The CFSS is also easy to manufacture with roll-to-roll nanoimprint lithography at a cost of <$12/m2. We design the CFSS using the COMSOL Wave Optics module to solve for electromagnetic wave propagation in optical media via the finite element method. The simulation domain is reduced to a single unit cell with periodic boundary conditions to account for the symmetries of the planar, periodic CFSS. The design is optimized using parametric sweeps around the various geometric components of the metallic nanoantenna. Our design achieves peak reflection of 80% at 1000 nm and has a broadband IR response that will allow for optimum solar control without significantly affecting the transmission of visible light.

Space Nuclear Power and Propulsion - a basic Tool for the manned Exploration of the Solar System

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

Frischauf, Norbert; Hamilton, Booz Allen

2004-07-01

Humanity has started to explore space more than 40 years ago. Numerous spacecraft have left the Earth in this endeavour, but while unmanned spacecraft were already sent out on missions, where they would eventually reach the outer limits of the Solar System, manned exploration has always been confined to the tiny bubble of the Earth's gravitational well, stretching out at maximum to our closest celestial companion - the Moon - during the era of the Apollo programme in the late 60's and early 70's. When mankind made its giant leap, the exploration of our cosmic neighbour was seen as themore » initial step for the manned exploration of the whole Solar System. Consequently ambitious research and development programmes were undertaken at that time to enable what seemed to be the next logical steps: the establishment of a permanent settled base on the Moon and the first manned mission to Mars in the 80's. Nuclear space power and propulsion played an important role in these entire future scenarios, hence ambitious development programmes were undertaken to make these technologies available. Unfortunately the 70's-paradigm shift in space policies did not only bring an end to the Apollo programme, but it also brought a complete halt to all of these technology programmes and confined the human presence in space to a tiny bubble including nothing more than the Earth's sphere and a mere shell of a few hundred kilometres of altitude, too small to even include the Moon. Today, after more than three decades, manned exploration of the Solar System has become an issue again and so are missions to Moon and Mars. However, studies and analyses show that all of these future plans are hampered by today's available propulsion systems and by the problematic of solar power generation at distances at and beyond of Mars, a problem, however, that can readily be solved by the utilisation of space nuclear reactors and propulsion systems. This paper intends to provide an overview on the various fission- and fusion-based Nuclear Power and Propulsion system concepts and tries to compare these systems' different working principles and technical implementations with each other. The overview and comparison will be complemented by a closer look at ongoing activities related to research and development in this area and by an outlook on what kind of systems might be employed to carry the first astronauts to Mars and beyond. (autho0008.« less

Modeling and optimization of a concentrated solar supercritical CO2 power plant

NASA Astrophysics Data System (ADS)

Osorio, Julian D.

Renewable energy sources are fundamental alternatives to supply the rising energy demand in the world and to reduce or replace fossil fuel technologies. In order to make renewable-based technologies suitable for commercial and industrial applications, two main challenges need to be solved: the design and manufacture of highly efficient devices and reliable systems to operate under intermittent energy supply conditions. In particular, power generation technologies based on solar energy are one of the most promising alternatives to supply the world energy demand and reduce the dependence on fossil fuel technologies. In this dissertation, the dynamic behavior of a Concentrated Solar Power (CSP) supercritical CO2 cycle is studied under different seasonal conditions. The system analyzed is composed of a central receiver, hot and cold thermal energy storage units, a heat exchanger, a recuperator, and multi-stage compression-expansion subsystems with intercoolers and reheaters between compressors and turbines respectively. The effects of operating and design parameters on the system performance are analyzed. Some of these parameters are the mass flow rate, intermediate pressures, number of compression-expansion stages, heat exchangers' effectiveness, multi-tank thermal energy storage, overall heat transfer coefficient between the solar receiver and the environment and the effective area of the recuperator. Energy and exergy models for each component of the system are developed to optimize operating parameters in order to lead to maximum efficiency. From the exergy analysis, the components with high contribution to exergy destruction were identified. These components, which represent an important potential of improvement, are the recuperator, the hot thermal energy storage tank and the solar receiver. Two complementary alternatives to improve the efficiency of concentrated solar thermal systems are proposed in this dissertation: the optimization of the system's operating parameters and optimization of less efficient components. The parametric optimization is developed for a 1MW reference CSP system with CO2 as the working fluid. The component optimization, focused on the less efficient components, comprises some design modifications to the traditional component configuration for the recuperator, the hot thermal energy storage tank and the solar receiver. The proposed optimization alternatives include the heat exchanger's effectiveness enhancement by optimizing fins shapes, multi-tank thermal energy storage configurations for the hot thermal energy storage tank and the incorporation of a transparent insulation material into the solar receiver. Some of the optimizations are conducted in a generalized way, using dimensionless models to be applicable no only to the CSP but also to other thermal systems. This project is therefore an effort to improve the efficiency of power generation systems based on solar energy in order to make them competitive with conventional fossil fuel power generation devices. The results show that the parametric optimization leads the system to an efficiency of about 21% and a maximum power output close to 1.5 MW. The process efficiencies obtained in this work, of more than 21%, are relatively good for a solar-thermal conversion system and are also comparable with efficiencies of conversion of high performance PV panels. The thermal energy storage allows the system to operate for several hours after sunset. This operating time is approximately increased from 220 to 480 minutes after optimization. The hot and cold thermal energy storage also lessens the temperature fluctuations by providing smooth changes of temperatures at the turbines' and compressors' inlets. Additional improvements in the overall system efficiency are possible by optimizing the less efficient components. In particular, the fin's effectiveness can be improved in more than 5% after its shape is optimized, increments in the efficiency of the thermal energy storage of about 5.7% are possible when the mass is divided into four tanks, and solar receiver efficiencies up to 70% can be maintained for high operating temperatures (~ 1200°C) when a transparent insulation material is incorporated to the receiver. The results obtained in this dissertation indicate that concentrated solar systems using supercritical CO2 could be a viable alternative to satisfying energy needs in desert areas with scarce water and fossil fuel resources.

CNO neutrino Grand Prix: the race to solve the solar metallicity problem

NASA Astrophysics Data System (ADS)

Cerdeño, David G.; Davis, Jonathan H.; Fairbairn, Malcolm; Vincent, Aaron C.

2018-04-01

Several next-generation experiments aim to make the first measurement of the neutrino flux from the Carbon-Nitrogen-Oxygen (CNO) solar fusion cycle. We calculate how much time these experiments will need to run for in order to measure this flux with enough precision to tell us the metal content of the Sun's core, and thereby help to solve the solar metallicity problem. For experiments looking at neutrino-electron scattering, we find that SNO+ will measure this CNO neutrino flux with enough precision after five years in its pure scintillator mode, provided its 210Bi background is measured to 1% accuracy. By comparison, a 100 ton liquid argon experiment such as Argo will take ten years in Gran Sasso lab, or five years in SNOLAB or Jinping. Borexino could obtain this precision in ten years, but this projection is very sensitive to background assumptions. For experiments looking at neutrino-nucleus scattering, the best prospects are obtained for low-threshold solid state detectors (employing either germanium or silicon). These would require new technologies to lower the experimental threshold close to detection of single electron-hole pairs, and exposures beyond those projected for next-generation dark matter detectors.

Indian summer monsoon rainfall: Dancing with the tunes of the sun

NASA Astrophysics Data System (ADS)

Hiremath, K. M.; Manjunath, Hegde; Soon, Willie

2015-02-01

There is strong statistical evidence that solar activity influences the Indian summer monsoon rainfall. To search for a physical link between the two, we consider the coupled cloud hydrodynamic equations, and derive an equation for the rate of precipitation that is similar to the equation of a forced harmonic oscillator, with cloud and rain water mixing ratios as forcing variables. Those internal forcing variables are parameterized in terms of the combined effect of external forcing as measured by sunspot and coronal hole activities with several well known solar periods (9, 13 and 27 days; 1.3, 5, 11 and 22 years). The equation is then numerically solved and the results show that the variability of the simulated rate of precipitation captures very well the actual variability of the Indian monsoon rainfall, yielding vital clues for a physical understanding that has so far eluded analyses based on statistical correlations alone. We also solved the precipitation equation by allowing for the effects of long-term variation of aerosols. We tentatively conclude that the net effects of aerosols variation are small, when compared to the solar factors, in terms of explaining the observed rainfall variability covering the full Indian monsoonal geographical domains.

Integrating Multiple Approaches to Solving Solar Wind Turbulence Problems (Invited)

NASA Astrophysics Data System (ADS)

Karimabadi, H.; Roytershteyn, V.

2013-12-01

The ultimate understanding of the solar wind turbulence must explain the physical process and their connection at all scales ranging from the largest down to electron kinetic scales. This is a daunting task and as a result a more piecemeal approach to the problem has been followed. For example, the role of each wave has been explored in isolation and in simulations with scales limited to those of the underlying waves. In this talk, we present several issues with this approach and offer an alternative with an eye towards more realistic simulations of solar wind turbulence. The main simulation techniques used have been MHD, Hall MHD, hybrid, fully kinetic, and gyrokinetic. We examine the limitations of each approach and their viability for studies of solar wind turbulence. Finally, the effect of initial conditions on the resulting turbulence and their comparison with solar wind are demonstrated through several kinetic simulations.

A search for the coronal origins of fast solar wind streams during the whole sun month period

NASA Technical Reports Server (NTRS)

Lazarus, A. J.; Steinberg, J. T.; Biesecker, D. A.; Forsyth, R. J.; Galvin, A. B.; Ipavich, F. M.; Gibson, S. E.; Lecinski, A.; Hassler, D. M.; Hoeksema, J. T.;

Engineering applications of metaheuristics: an introduction

NASA Astrophysics Data System (ADS)

Oliva, Diego; Hinojosa, Salvador; Demeshko, M. V.

2017-01-01

Metaheuristic algorithms are important tools that in recent years have been used extensively in several fields. In engineering, there is a big amount of problems that can be solved from an optimization point of view. This paper is an introduction of how metaheuristics can be used to solve complex problems of engineering. Their use produces accurate results in problems that are computationally expensive. Experimental results support the performance obtained by the selected algorithms in such specific problems as digital filter design, image processing and solar cells design.

A new technique for solving the Parker-type wind equations

NASA Technical Reports Server (NTRS)

Melia, Fulvio

1988-01-01

Substitution of the novel function Phi for velocity, as one of the dependent variables in Parker-type solar wind equations, removes the critical point, and therefore the numerical difficulties encountered, from the set of coupled differential wind equations. The method has already been successfully used in a study of radiatively-driven mass loss from the surface of X-ray bursting neutron stars. The present technique for solving the equations of time-independent mass loss can be useful in similar applications.

Space Power Engineering Problems

NASA Astrophysics Data System (ADS)

Senkevich, V. P.

2002-01-01

Development of space power engineering in the first half of XXI century shall be aimed at preventing the forthcoming energy crisis and ecological catastrophes. The problem can be solved through using solar energy being perpetual, endless, and ecologically safe. As of now, issues on the development and employment of solar power stations and its beaming to the ground stations in the SHF band are put on the agenda. The most pressing problem is to develop orbital solar reflectors to illuminate towns in the polar regions, agricultural regions, and areas of processing sea products. Space-based technologies can be used to deal with typhoons, green house effects, and "ozone holes". Recently, large, frameless film structures formed by centrifugal forces offer the promise of structures for orbital power plants, reflectors, and solar sails. A big success is achieved in the development of power generating solar array elements of amorphous silicon. These innovations would make the development of orbital solar power plants dozens of times cheaper. Such solar arrays shall be used in the nearest future on heavy communication satellites and the Earth remote sensing platforms for generation of 140-160 kW at a specific power beyond 300 W/kg. The cargo traffic needed to develop and maintain the orbital power plants and reflector systems could be equipped with solar sails as the future low thrust propulsion. In 2000, the mankind witnessed an unexpected beginning of energy crisis along with strong hydro- meteorological events (typhoons, floods) that shocked the USA, the Western Europe, England, Japan, and other countries. The total damage is estimated as 90 billions of dollars. The mankind is approaching a boundary beyond which its further existence would depend on how people would learn to control weather and use ecologically safe power sources. Space technology base on the research potential accumulated in the previous century could serve for the solution of this problem.

Thickness dependences of solar cell performance

NASA Technical Reports Server (NTRS)

Sah, C. T.

1982-01-01

The significance of including factors such as the base resistivity loss for solar cells thicker than 100 microns and emitter and BSF layer recombination for thin cells in predicting the fill factor and efficiency of solar cells is demonstrated analytically. A model for a solar cell is devised with the inclusion of the dopant impurity concentration profile, variation of the electron and hole mobility with dopant concentration, the concentration and thermal capture and emission rates of the recombination center, device temperature, the AM1 spectra and the Si absorption coefficient. Device equations were solved by means of the transmission line technique. The analytical results were compared with those of low-level theory for cell performance. Significant differences in predictions of the fill factor resulted, and inaccuracies in the low-level approximations are discussed.

A theoretical study of heterojunction and graded band gap type solar cells

NASA Technical Reports Server (NTRS)

Sutherland, J. E.; Hauser, J. R.

1977-01-01

A computer program was designed for the analysis of variable composition solar cells and applied to several proposed solar cell structures using appropriate semiconductor materials. The program simulates solar cells made of a ternary alloy of two binary semiconductors with an arbitrary composition profile, and an abrupt or Gaussian doping profile of polarity n-on-p or p-on-n with arbitrary doping levels. Once the device structure is specified, the program numerically solves a complete set of differential equations and calculates electrostatic potential, quasi-Fermi levels, carrier concentrations and current densities, total current density and efficiency as functions of terminal voltage and position within the cell. These results are then recorded by computer in tabulated or plotted form for interpretation by the user.

Solar Pilot Plant, Phase I. Preliminary design report. Volume II, Book 2. Central receiver optical model users manual. CDRL item 2. [HELIAKI code

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

None

1977-05-01

HELIAKI is a FORTRAN computer program which simulates the optical/thermal performance of a central receiver solar thermal power plant for the dynamic conversion of solar-generated heat to electricity. The solar power plant which this program simulates consists of a field of individual sun tracking mirror units, or heliostats, redirecting sunlight into a cavity, called the receiver, mounted atop a tower. The program calculates the power retained by that cavity receiver at any point in time or the energy into the receiver over a year's time using a Monte Carlo ray trace technique to solve the multiple integral equations. An artist'smore » concept of this plant is shown.« less

First calibration results and antenna placement studies of the RPW ANT instrument on Solar Orbiter

NASA Astrophysics Data System (ADS)

Sampl, M.; Oswald, T. H.; Rucker, H. O.; Plettemeier, D.; Maksimovic, M.; Macher, W.

2010-12-01

We report our analyses of the Radio and Plasma Wave Analyzer (RPW ANT) onboard the Solar Orbiter spacecraft with a focus on the high-frequency electric antennas. The aim of the Solar Orbiter mission is to determine in-situ properties and dynamics of solarwind plasma, electric and magnetic fields in the near-Sun heliosphere. The mission is planned to be launched in 2017 with a spacecraft trajectory of, for the first time, partial co-rotation with the Sun, providing a full suite of in-situ and remote sensing instruments from as close as 0.25 AU. The RPW ANT high-frequency electric sensors, consist of three cylindrical antennas mounted on appendant booms extruded from the central body of the spacecraft. Due to the parasitic effects of the conducting spacecraft body and solar panels the true antenna properties (effective axes and length; capacitances) do not coincide with their physical representations. In order to analyze the antenna system we applied a numerical method. The current distribution on the spacecraft body and the effective length vector was calculated, by solving the underlying field equations using electromagnetic codes. In the applied method the spacecraft is modelled as a patch-grid. The numerical analysis of the reception properties, including several placement options of these antennas, is presented. Since the Solar Orbiter spacecraft body and antennas are not yet finally specified, the results can be used to evaluate the performance of the proposed sensors. In particular, goniopolarimetry techniques like polarization analysis, direction finding and ray tracing depend crucially on the effective axes and the therefore the corresponding data analysis significantly improves. Software model (patch-grid) of the Solar Orbiter spacecraft

A Model of Magnetic Braking of Solar Rotation that Satisfies Observational Constraints

NASA Astrophysics Data System (ADS)

Denissenkov, Pavel A.

2010-08-01

The model of magnetic braking of solar rotation considered by Charbonneau & MacGregor has been modified so that it is able to reproduce for the first time the rotational evolution of both the fastest and slowest rotators among solar-type stars in open clusters of different ages, without coming into conflict with other observational constraints, such as the time evolution of the atmospheric Li abundance in solar twins and the thinness of the solar tachocline. This new model assumes that rotation-driven turbulent diffusion, which is thought to amplify the viscosity and magnetic diffusivity in stellar radiative zones, is strongly anisotropic with the horizontal components of the transport coefficients strongly dominating over those in the vertical direction. Also taken into account is the poloidal field decay that helps to confine the width of the tachocline at the solar age. The model's properties are investigated by numerically solving the azimuthal components of the coupled momentum and magnetic induction equations in two dimensions using a finite element method.

The Effect of Ionic Correlations on Radiative Properties in the Solar Interior and Terrestrial Experiments

NASA Astrophysics Data System (ADS)

Krief, Menahem; Kurzweil, Yair; Feigel, Alexander; Gazit, Doron

2018-04-01

With the aim of solving the decade-old problem of solar opacity, we report substantial photoabsorption uncertainty due to the effect of ion–ion correlations. By performing detailed opacity calculations of the solar mixture, we find that taking into account the ionic structure changes the Rosseland opacity near the convection zone by ∼10%. We also report a ∼15% difference in the Rosseland opacity for iron, which was recently measured at the Sandia Z facility, where the temperature reached that prevailing in the convection zone boundary while the density was 2.5 times lower. Finally, we propose a method to measure opacities at solar temperatures and densities that have never been reached in the past via laboratory radiation flow experiments, by using plastic foams doped with permilles of dominant photon absorbers in the Sun. The method is advantageous for an experimental study of solar opacities that may lead to a resolution of the solar abundance problem.

Superconducting Magnet Shielding of Astronauts from Cosmic Rays

NASA Astrophysics Data System (ADS)

Fisher, Peter; Hoffman, Jeffrey; Zhou, Feng; Batishchev, Oleg

2004-11-01

Protecting astronauts traveling outside the Earth's protective magnetic field from cosmic and solar radiation [1] is one of the critical problems that must be solved in order to realize the nation's new human space exploration vision. Superconducting magnets, such as those under construction for the ATLAS experiment [2] at CERN, have achieved sufficient size to be able to surround a reasonable habitable volume, and their field strength is high enough to deflect a significant portion of the incoming radiation. We have undertaken a research effort aimed at developing an accurate numerical model of a crew compartment surrounded by a large magnetic field, with which we can calculate the effect on incoming charged particles. We will use this model to optimize the magnetic configuration to produce the maximum shielding effect while minimizing the mass of the superconducting magnet system. We are also investigating some of the practical problems that must be solved if large, superconducting magnet systems are to be incorporated into human space systems. We will present preliminary results of our modeling, showing the reduction of radiation exposure as a function of energy and atomic species. [1] Review of Particle Physics, Ed. Particle Data Group, Phys. Lett. B, 1-4 (592) 1-1109, 2004 [2] http://atlasexperiment.org/

Novel Design Strategies for Platinum-Containing Conjugated Polymers and Small Molecules for Organic Solar Cells

NASA Astrophysics Data System (ADS)

He, Wenhan

Current state-of-the-art organic solar cells (OSCs) adopt the strategy of using conjugated polymers or small molecules as donors and fullerene derivatives as acceptors in their active layers. Regarding to the donors of interest, the conjugated polymers and small molecules coupled with heavy metals have been less explored compared to their counterparts. Among various transition metal complexes applied, Pt(II) complexes are unique because of their intrinsic square planar geometries and ability to serve as building blocks for conjugated systems. Furthermore, the heavy metal Pt facilitates the formation of triplet excitons with longer life times through spin-orbital coupling which are of benefit for the OSCs application. However, in order to obtain low bandgap polymers, people are intended to use chromophores with long conjugated length, nevertheless such design will inevitably dilute the spin-orbital coupling effect and finally influence the formation of triplet excitons. Furthermore, the majority of Pt-containing conjugated systems reported so far shared a common feature-- they all possessed "dumbbell" shaped structures and were amorphous, leading to poor device performance. In addition, there were few examples reporting the capture of the triplet excitons by the fullerene acceptors in the OSCs since there is a mismatch between the triplet energy state (T1) of the Pt-containing compounds and the LUMO level of fullerene acceptors. As a result, these three intrinsic problems will impede the further development of such a field. In order to solve these problems, I originally designed and synthesized three novel compounds with unique proprieties named as Bodipy-Pt, Pt-SM and C60+SDS-. Specifically, Bodipy has the advantages of compact size, easy to synthesis and high fluorescence quantum yield which can effectively solve the problem of long conjugated length. While in terms of second problem, the new Pt-SM possessed a "roller-wheel" structural design with increased crystallinity through slip-stack packing; the solar cell efficiency of this compound out-performed all existing Pt-containing materials in organic solar cells. I have further studied the photophysical behavior of the molecule through time-resolved transient absorption spectroscopy as well as DFT calculation. Finally, because of its ionic nature, the LUMO level of C60+SDS- is lower than that of PCBM which serves as a common fullerene acceptor applied in the organic solar cell. Above all, through the measurement of time-resolved transient absorption, I have confirmed the C60+SDS - can capture the triplet exciton of Pt-SM through dynamic quenching since the life-time of triplet exciton has decreased after adding C60 +SDS- solution.

Haze and cloud distribution in Uranus' atmosphere based on high-contrast spatially resolved polarization measurements

NASA Astrophysics Data System (ADS)

Kostogryz, Nadiia; Berdyugina, Svetlana; Gisler, Daniel; Berkefeld, Thomas

2017-04-01

In planetary atmospheres, main sources of opacity are molecular absorption and scattering on molecules, hazes and aerosols. Hence, light reflected from a planetary atmosphere can be linearly polarized. Polarization study of inner solar system planets and exoplanets is a powerful method to characterize their atmospheres, because of a wide range of observable phase angles. For outer solar system planets, observable phase angles are very limited. For instance, Uranus can only be observed up to 3.2 degrees away from conjunctions, and its disk-integrated polarization is close to zero due to the back-scattering geometry. However, resolving the disk of Uranus and measuring the center-to-limb polarization can help constraining the vertical atmospheric structure and the nature of scattering aerosols and particles. In October 2016, we carried out polarization measurements of Uranus in narrow-band filters centered at methane bands and the adjacent continuum using the GREGOR Planet Polarimeter (GPP). The GPP is a high-precision polarimeter and is mounted at the 1.5-m GREGOR solar telescope, which is suitable for observing at night. In order to reach a high spatial resolution, the instrument uses an adaptive-optics system of the telescope. To interpret our measurements, we solve the polarized radiative transfer problem taking into account different scattering and absorption opacities. We calculate the center-to-limb variation of polarization of Uranus' disk in the continuum spectrum and in methane bands. By varying the vertical distribution of haze and cloud layers, we derive the vertical structure of the best-fit Uranus atmosphere.

Probing the Solar System with LSST

NASA Astrophysics Data System (ADS)

Harris, A.; Ivezic, Z.; Juric, M.; Lupton, R.; Connolly, A.; Kubica, J.; Moore, A.; Bowell, E.; Bernstein, G.; Cook, K.; Stubbs, C.

2005-12-01

LSST will catalog small Potentially Hazardous Asteroids (PHAs), survey the main belt asteroid (MBA) population to extraordinarily small size, discover comets far from the sun where their nuclear properties can be discerned without coma, and survey the Centaur and Trans-Neptunian Object (TNO) populations. The present planned observing strategy is to ``visit'' each field (9.6 deg2) with two back-to-back exposures of ˜ 15 sec, reaching to at least V magnitude 24.5. An intra-night revisit time of the order half an hour will distinguish stationary transients from even very distant ( ˜ 70 AU) solar system bodies. In order to link observations and determine orbits, each sky area will be visited several times during a month, spaced by about a week. This cadence will result in orbital parameters for several million MBAs and about 20,000 TNOs, with light curves and colorimetry for the brighter 10% or so of each population. Compared to the current data available, this would represent factor of 10 to 100 increase in the numbers of orbits, colors, and variability of the two classes of objects. The LSST MBA and TNO samples will enable detailed studies of the dynamical and chemical history of the solar system. The increase in data volume associated with LSST asteroid science will present many computational challenges to how we might extract tracks and orbits of asteroids from the underlying clutter. Tree-based algorithms for multihypothesis testing of asteroid tracks can help solve these challenges by providing the necessary 1000-fold speed-ups over current approaches while recovering 95% of the underlying moving objects.

Lessons Learned to Date in Developing the Virtual Space Physics Observatory

NASA Astrophysics Data System (ADS)

Cornwell, C.; Roberts, D. A.; King, J.; Smith, A.

2005-12-01

We now have an operational Virtual Space Physics Observatory that provides users the ability to search for and retrieve data from hundreds of space and solar physics data products based on specific terms or a Google-like interface. Lessons learned in building VSPO include: (a) A very close and highly interactive collaboration between scientists and information technologists in the definition and development of services is essential. (b) Constructing a Data Model acceptable to a broad community is very important but very difficult. Variations in usage are inevitable and must be dealt with through translations; this is especially true for the description of variables within data products. (c) Higher-order queries (searches based on events, positions, comparisons of measurements, etc.) are possible, and have been implemented in various systems; currently we see these as being separate from the basic data finding and retrieval services. (d) Building a Virtual Observatory is often more a matter of the tedious details of product descriptions than an exercise in implementing fancy middleware. Paying a knowledgeable third party to build registries can be more efficient than working directly with providers, and automated tools can help but do not solve all the problems. (e) The success of the VO effort in space and solar physics, as elsewhere, will depend on whether the scientific communities involved use and critique the services so that they will come to meet a real need for the integration of resources to solve new scientific problems of perceived importance.

Generalized Differential Calculus and Applications to Optimization

NASA Astrophysics Data System (ADS)

Rector, Robert Blake Hayden

This thesis contains contributions in three areas: the theory of generalized calculus, numerical algorithms for operations research, and applications of optimization to problems in modern electric power systems. A geometric approach is used to advance the theory and tools used for studying generalized notions of derivatives for nonsmooth functions. These advances specifically pertain to methods for calculating subdifferentials and to expanding our understanding of a certain notion of derivative of set-valued maps, called the coderivative, in infinite dimensions. A strong understanding of the subdifferential is essential for numerical optimization algorithms, which are developed and applied to nonsmooth problems in operations research, including non-convex problems. Finally, an optimization framework is applied to solve a problem in electric power systems involving a smart solar inverter and battery storage system providing energy and ancillary services to the grid.

Wireless Power Transmission Options for Space Solar Power

NASA Technical Reports Server (NTRS)

Henley, M. W.; Potter, Seth D.; Howell, J.; Mankins, J. C.; Fikes, John C. (Technical Monitor)

2002-01-01

Space Solar Power (SSP). combined with Wireless Power Transmission (WPT), offers the far-term potential to solve major energy problems on Earth. In this paper WPT options using radio waves and light waves are considered for both long-term and near-term SSP applications. In the long-term, we aspire to beam energy to Earth from geostationary Earth orbit (GEO), or even from the moon. Accordingly, radio- and light- wave WPT options are compared through a wide range of criteria, each showing certain strengths. In the near-term. we plan to beam power over more moderate distances, but still stretch the limits of today's technology. For the near-term, a 100 kWe-class 'Power Plug' Satellite and a 10 kWe-class Lunar Polar Solar Power outpost are considered as the first steps in using these WPT options for SSP. By using SSP and WPT technology in near-term space science and exploration missions, we gain experience needed for sound decisions in designing and developing larger systems to send power from Space to Earth. Power Relay Satellites are also considered as a potential near- to mid-term means to transmit power from Earth to Space and back to distant receiving sites on Earth. This paper briefly considers microwave and laser beaming for an initial Power Relay Satellite system, and concludes that anticipated advancements in laser technology make laser-based concepts more attractive than microwave-based concepts. Social and economic considerations are briefly discussed, and a conceptual description for a laser-based system is offered for illustrative purposes. Continuing technological advances are needed if laser-based systems are to become practical and efficient or near- and far-term applications.

Optimization of the functional domain of flat plate collectors

NASA Astrophysics Data System (ADS)

Ritoux, G.; Irigaray, J.-L.

1981-12-01

The variations of the extracted heat flux as function of the temperature of the heat transfer fluid in black and selective surface solar collectors are examined. The heat flux is calculated based on the difference of the initial to the stage of thermal equilibrium of the fluid. A nonlinear system of equations is developed and solved by a fast, iterative method to obtain the equilibrium temperatures. It is found that more flux can be extracted from the solar heat by a collector with only one glass cover than with more than one cover. The captured flux is proportional to the coefficient of transmission of the glass coverings, to the coefficient of absorption of the collector, and to the incident flux. Black painted surfaces were more absorbent than selective surfaces, and highest collection efficiencies were displayed by low temperature collectors. Charts of effective uses of the respective types of collectors for heating swimming pools, hot water, home heat, and for refrigeration and air-conditioning are provided.

An Analysis of Processes in the Solar Wind in a Thin Layer Adjacent to the Front of the Shock Wave

NASA Astrophysics Data System (ADS)

Molotkov, I. A.; Atamaniuk, B.

2018-05-01

A two-dimensional stationary system of nonlinear magnetohydrodynamics (MHD) equations in a thin layer adjoining the front of the interplanetary shock wave has been solved. Previously, any available publications relied on linear transport equations. But the presence of high-energy particles in the solar wind (SW) requires taking into account the processes of self-interaction. Our analysis examines the nonlinear terms in the MHD equations. A solution has been constructed for three cases: (1) in the absence of magnetic reconnections; (2) for magnetic reconnections; and (3) with the simultaneous action of reconnections and junction of magnetic islands. In all three cases, expressions were found for the main parameters of the SW. The results obtained on the basis of the solution of the MHD equations are consistent with the conclusions based on the investigation of the particle velocity distribution functions. This makes it possible to confirm the previously established fraction of particles excited to energies above 1 MeV.

Pickup Ion Effect of the Solar Wind Interaction with the Local Interstellar Medium

DOE PAGES

Pogorelov, N. V.; Bedford, M. C.; Kryukov, I. A.; ...

2016-11-22

Pickup ions are created when interstellar neutral atoms resonantly exchange charge with the solar wind (SW) ions, especially in the supersonic part of the wind, where they carry most of the plasma pressure. Here we present numerical simulation results of the 3D heliospheric interface treating pickup ions as a separate proton fluid. To satisfy the fundamental conservation laws, we solve the system of equations describing the flow of the mixture of electrons, thermal protons, and pickup ions. To find the density and pressure of pickup ions behind the termination shock, we employ simple boundary conditions that take into account themore » \\emph{Voyager} observations that showed that the decrease in the kinetic energy of the mixture at the termination shock predominantly contributed to the increase in the pressure of pickup ions. We show that this model adequately describes the flow of the plasma mixture and results in a noticeable decrease in the heliosheath width.« less

Modular Cascaded H-Bridge Multilevel PV Inverter with Distributed MPPT for Grid-Connected Applications

DOE PAGES

Xiao, Bailu; Hang, Lijun; Mei, Jun; ...

2014-09-04

This paper presents a modular cascaded H-bridge multilevel photovoltaic (PV) inverter for single- or three-phase grid-connected applications. The modular cascaded multilevel topology helps to improve the efficiency and flexibility of PV systems. To realize better utilization of PV modules and maximize the solar energy extraction, a distributed maximum power point tracking (MPPT) control scheme is applied to both single-phase and three-phase multilevel inverters, which allows the independent control of each dc-link voltage. For three-phase grid-connected applications, PV mismatches may introduce unbalanced supplied power, leading to unbalanced grid current. To solve this issue, a control scheme with modulation compensation is alsomore » proposed. An experimental three-phase 7-level cascaded H-bridge inverter has been built utilizing 9 H-bridge modules (3 modules per phase). Each H-bridge module is connected to a 185 W solar panel. Simulation and experimental results are presented to verify the feasibility of the proposed approach.« less

Photosynthetic solar cell using nanostructured proton exchange membrane for microbial biofilm prevention.

PubMed

Lee, Dong Hyun; Oh, Hwa Jin; Bai, Seoung Jae; Song, Young Seok

2014-06-24

Unwanted biofilm formation has a detrimental effect on bioelectrical energy harvesting in microbial cells. This issue still needs to be solved for higher power and longer durability and could be resolved with the help of nanoengineering in designing and manufacturing. Here, we demonstrate a photosynthetic solar cell (PSC) that contains a nanostructure to prevent the formation of biofilm by micro-organisms. Nanostructures were fabricated using nanoimprint lithography, where a film heater array system was introduced to precisely control the local wall temperature. To understand the heat and mass transfer phenomena behind the manufacturing and energy harvesting processes of PSC, we carried out a numerical simulation and experimental measurements. It revealed that the nanostructures developed on the proton exchange membrane enable PSC to produce enhanced output power due to the retarded microbial attachment on the Nafion membrane. We anticipate that this strategy can provide a pathway where PSC can ensure more renewable, sustainable, and efficient energy harvesting performance.

AI techniques for a space application scheduling problem

NASA Technical Reports Server (NTRS)

Thalman, N.; Sparn, T.; Jaffres, L.; Gablehouse, D.; Judd, D.; Russell, C.

1991-01-01

Scheduling is a very complex optimization problem which can be categorized as an NP-complete problem. NP-complete problems are quite diverse, as are the algorithms used in searching for an optimal solution. In most cases, the best solutions that can be derived for these combinatorial explosive problems are near-optimal solutions. Due to the complexity of the scheduling problem, artificial intelligence (AI) can aid in solving these types of problems. Some of the factors are examined which make space application scheduling problems difficult and presents a fairly new AI-based technique called tabu search as applied to a real scheduling application. the specific problem is concerned with scheduling application. The specific problem is concerned with scheduling solar and stellar observations for the SOLar-STellar Irradiance Comparison Experiment (SOLSTICE) instrument in a constrained environment which produces minimum impact on the other instruments and maximizes target observation times. The SOLSTICE instrument will gly on-board the Upper Atmosphere Research Satellite (UARS) in 1991, and a similar instrument will fly on the earth observing system (Eos).

Depolarizing collisions with hydrogen: Neutral and singly ionized alkaline earths

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

Manso Sainz, Rafael; Ramos, Andrés Asensio; Bueno, Javier Trujillo

2014-06-20

Depolarizing collisions are elastic or quasielastic collisions that equalize the populations and destroy the coherence between the magnetic sublevels of atomic levels. In astrophysical plasmas, the main depolarizing collider is neutral hydrogen. We consider depolarizing rates on the lowest levels of neutral and singly ionized alkali earths Mg I, Sr I, Ba I, Mg II, Ca II, and Ba II, due to collisions with H°. We compute ab initio potential curves of the atom-H° system and solve the quantum mechanical dynamics. From the scattering amplitudes, we calculate the depolarizing rates for Maxwellian distributions of colliders at temperatures T ≤ 10,000more » K. A comparative analysis of our results and previous calculations in the literature is completed. We discuss the effect of these rates on the formation of scattering polarization patterns of resonant lines of alkali earths in the solar atmosphere, and their effect on Hanle effect diagnostics of solar magnetic fields.« less

Hybrid thermoelectric solar collector design and analysis

NASA Technical Reports Server (NTRS)

Roberts, A. S., Jr.; Shaheen, K. E.

1982-01-01

A flat-plate solar collector is conceived where energy cascades through thermoelectric power modules generating direct-current electricity. The intent of this work was to choose a collector configuration and to perform a steady-state thermal performance assessment. A set of energy balance equations were written and solved numerically for the purpose of optimizing collector thermal and electrical performance. The collector design involves finned columns of thermoelectric modules imbedded in the absorber plate (hot junction) over a parallel array of vertical tubes. The thermoelectric power output is limited by the small hot-junction/cold-junction temperature difference which can be maintained under steady-state conditions. The electric power per unit tube pass area is found to have a maximum as a function of a geometric parameter, while electric power is maximized with respect to an electric resistance ratio. Although the electric power efficiency is small, results indicate that there is sufficient electric power production to drive a coolant circulator, suggesting the potential for a stand-alone system.

Model Predictive Control-based Optimal Coordination of Distributed Energy Resources

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

Mayhorn, Ebony T.; Kalsi, Karanjit; Lian, Jianming

2013-01-07

Distributed energy resources, such as renewable energy resources (wind, solar), energy storage and demand response, can be used to complement conventional generators. The uncertainty and variability due to high penetration of wind makes reliable system operations and controls challenging, especially in isolated systems. In this paper, an optimal control strategy is proposed to coordinate energy storage and diesel generators to maximize wind penetration while maintaining system economics and normal operation performance. The goals of the optimization problem are to minimize fuel costs and maximize the utilization of wind while considering equipment life of generators and energy storage. Model predictive controlmore » (MPC) is used to solve a look-ahead dispatch optimization problem and the performance is compared to an open loop look-ahead dispatch problem. Simulation studies are performed to demonstrate the efficacy of the closed loop MPC in compensating for uncertainties and variability caused in the system.« less

Model Predictive Control-based Optimal Coordination of Distributed Energy Resources

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

Mayhorn, Ebony T.; Kalsi, Karanjit; Lian, Jianming

2013-04-03

Distributed energy resources, such as renewable energy resources (wind, solar), energy storage and demand response, can be used to complement conventional generators. The uncertainty and variability due to high penetration of wind makes reliable system operations and controls challenging, especially in isolated systems. In this paper, an optimal control strategy is proposed to coordinate energy storage and diesel generators to maximize wind penetration while maintaining system economics and normal operation performance. The goals of the optimization problem are to minimize fuel costs and maximize the utilization of wind while considering equipment life of generators and energy storage. Model predictive controlmore » (MPC) is used to solve a look-ahead dispatch optimization problem and the performance is compared to an open loop look-ahead dispatch problem. Simulation studies are performed to demonstrate the efficacy of the closed loop MPC in compensating for uncertainties and variability caused in the system.« less

High-Speed Solution of Spacecraft Trajectory Problems Using Taylor Series Integration

NASA Technical Reports Server (NTRS)

Scott, James R.; Martini, Michael C.

2010-01-01

It has been known for some time that Taylor series (TS) integration is among the most efficient and accurate numerical methods in solving differential equations. However, the full benefit of the method has yet to be realized in calculating spacecraft trajectories, for two main reasons. First, most applications of Taylor series to trajectory propagation have focused on relatively simple problems of orbital motion or on specific problems and have not provided general applicability. Second, applications that have been more general have required use of a preprocessor, which inevitably imposes constraints on computational efficiency. The latter approach includes the work of Berryman et al., who solved the planetary n-body problem with relativistic effects. Their work specifically noted the computational inefficiencies arising from use of a preprocessor and pointed out the potential benefit of manually coding derivative routines. In this Engineering Note, we report on a systematic effort to directly implement Taylor series integration in an operational trajectory propagation code: the Spacecraft N-Body Analysis Program (SNAP). The present Taylor series implementation is unique in that it applies to spacecraft virtually anywhere in the solar system and can be used interchangeably with another integration method. SNAP is a high-fidelity trajectory propagator that includes force models for central body gravitation with N X N harmonics, other body gravitation with N X N harmonics, solar radiation pressure, atmospheric drag (for Earth orbits), and spacecraft thrusting (including shadowing). The governing equations are solved using an eighth-order Runge-Kutta Fehlberg (RKF) single-step method with variable step size control. In the present effort, TS is implemented by way of highly integrated subroutines that can be used interchangeably with RKF. This makes it possible to turn TS on or off during various phases of a mission. Current TS force models include central body gravitation with the J2 spherical harmonic, other body gravitation, thrust, constant atmospheric drag from Earth's atmosphere, and solar radiation pressure for a sphere under constant illumination. The purpose of this Engineering Note is to demonstrate the performance of TS integration in an operational trajectory analysis code and to compare it with a standard method, eighth-order RKF. Results show that TS is 16.6 times faster on average and is more accurate in 87.5% of the cases presented.

Photoelectrocatalytic reduction of CO2 to methanol over a photosystem II-enhanced Cu foam/Si-nanowire system.

PubMed

Lian, Zichao; Pan, Donglai; Wang, Wenchao; Zhang, Dieqing; Li, Guisheng; Li, Hexing

2017-10-01

A solar-light double illumination photoelectrocatalytic cell (SLDIPEC) was fabricated for autonomous CO 2 reduction and O 2 evolution with the aid of photosystem II (PS-II, an efficient light-driven water-oxidized enzyme from nature) and utilized in a photoanode solution. The proposed SLPEC system was composed of Cu foam as the photoanode and p-Si nanowires (Si-NW) as the photocathode. Under solar irradiation, it exhibited a super-photoelectrocatalytic performance for CO 2 conversion to methanol, with a high evolution rate (41.94mmol/hr), owing to fast electron transfer from PS-II to Cu foam. Electrons were subsequently trapped by Si-NW through an external circuit via bias voltage (0.5V), and a suitable conduction band potential of Si (-0.6eV) allowed CO 2 to be easily reduced to CH 3 OH at the photocathode. The constructed Z-scheme between Cu foam and Si-NW can allow the SLDIPEC system to reduce CO 2 (8.03mmol/hr) in the absence of bias voltage. This approach makes full use of the energy band mismatch of the photoanode and photocathode to design a highly efficient device for solving environmental issues and producing clean energy. Copyright © 2017. Published by Elsevier B.V.

MAGNETO-ACOUSTIC WAVES IN A GRAVITATIONALLY STRATIFIED MAGNETIZED PLASMA: EIGEN-SOLUTIONS AND THEIR APPLICATIONS TO THE SOLAR ATMOSPHERE

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

Mather, J. F.; Erdélyi, R., E-mail: robertus@sheffield.ac.uk

2016-05-10

Magneto-acoustic gravity (MAG) waves have been studied intensively in the context of astrophysical plasmas. There are three popular choices of analytic modeling using a Cartesian coordinate system: a magnetic field parallel, perpendicular, or at an angle to the gravitational field. Here, we study a gravitationally stratified plasma embedded in a parallel, so called vertical, magnetic field. We find a governing equation for the auxiliary quantity Θ = p {sub 1}/ ρ {sub 0}, and find solutions in terms of hypergeometric functions. With the convenient relationship between Θ and the vertical velocity component, v {sub z}, we derive the solution formore » v{sub z}. We show that the four linearly independent functions for v{sub z} can also be cast as single hypergeometric functions, rather than the Frobenius series derived by Leroy and Schwartz. We are then able to analyze a case of approximation for a one-layer solution, taking the small wavelength limit. Motivated by solar atmospheric applications, we finally commence study of the eigenmodes of perturbations for a two-layer model using our solutions, solving the dispersion relation numerically. We show that, for a transition between a photospheric and chromospheric plasma embedded in a vertical magnetic field, modes exist that are between the observationally widely investigated three and five minute oscillation periods, interpreted as solar global oscillations in the lower solar atmosphere . It is also shown that, when the density contrast between the layers is large (e.g., applied to photosphere/chromosphere-corona), the global eigenmodes are practically a superposition of the same as in each of the separate one-layer systems.« less

Ideal heat transfer conditions for tubular solar receivers with different design constraints

NASA Astrophysics Data System (ADS)

Kim, Jin-Soo; Potter, Daniel; Gardner, Wilson; Too, Yen Chean Soo; Padilla, Ricardo Vasquez

2017-06-01

The optimum heat transfer condition for a tubular type solar receiver was investigated for various receiver pipe size, heat transfer fluid, and design requirement and constraint(s). Heat transfer of a single plain receiver pipe exposed to concentrated solar energy was modelled along the flow path of the heat transfer fluid. Three different working fluids, molten salt, sodium, and supercritical carbon dioxide (sCO2) were considered in the case studies with different design conditions. The optimized ideal heat transfer condition was identified through fast iterative heat transfer calculations solving for all relevant radiation, conduction and convection heat transfers throughout the entire discretized tubular receiver. The ideal condition giving the best performance was obtained by finding the highest acceptable solar energy flux optimally distributed to meet different constraint(s), such as maximum allowable material temperature of receiver, maximum allowable film temperature of heat transfer fluid, and maximum allowable stress of receiver pipe material. The level of fluid side turbulence (represented by pressure drop in this study) was also optimized to give the highest net power production. As the outcome of the study gives information on the most ideal heat transfer condition, it can be used as a useful guideline for optimal design of a real receiver and solar field in a combined manner. The ideal heat transfer condition is especially important for high temperature tubular receivers (e.g. for supplying heat to high efficiency Brayton cycle turbines) where the system design and performance is tightly constrained by the receiver pipe material strength.

A global renewable mix with proven technologies and common materials

NASA Astrophysics Data System (ADS)

Ballabrera, J.; Garcia-Olivares, A.; Garcia-Ladona, E.; Turiel, A.

2012-04-01

A global alternative mix to fossil fuels is proposed, based on proven renewable energy technologies that do not use scarce materials. Taking into account the availability of materials, the resulting mix consists of a combination of onshore and offshore wind turbines, concentrating solar power stations, hydroelectricity and wave power devices attached to the offshore turbines. Solar photovoltaic power could contribute to the mix if its dependence on scarce materials is solved. Material requirements are studied for the generation, power transport and for some future transport systems. The order of magnitude of copper, aluminium, neodymium, lithium, nickel, zinc and platinum that might be required for the proposed solution is obtained and compared with available reserves. While the proposed global alternative to fossil fuels seems technically feasible, lithium, nickel and platinum could become limiting materials for future vehicles fleet if no global recycling system were implemented and rechargeable zinc-air batteries could not be developed. As much as 60% of the current copper reserves would have to be employed in the implementation of the proposed solution. Altogether, the availability of materials may become a long-term physical constraint, preventing the continuation of the usual exponential growth of energy consumption.

Towards an understanding of the origin of the Solar system

NASA Astrophysics Data System (ADS)

Griv, Evgeny

Kant (1755) and Laplace (1796) built own hypothesis on the idea of Sun and planets forming from a scattering substance in space. It is well-known the main difficult of the Kant-Laplace hypothesis consists in appearance of angular momentum exploring. Attempts to find a plausible naturalistic explanation of the origin of the solar system in the framework of Safronov's (1969) hypothesis of accretion began about 50 years ago but have not yet been quantitatively successful. Accordingly, planets formed by accretion of solid particles, with or without the presence of gas during the later stages of planetary formation. The main problem is the timescale, which is comparable to or longer than estimates of the lifetime of planet-forming disks. In this work the position is adopted that involve a simultaneous formation of the Sun and the rest of the solar system through a gravitational instability in early solar nebula. In our model, planetary formation is thought to start with inelastically colliding gaseous and dust particles settling to the central plane of this rotating nebula to form a thin layer around the plane. On attaining a certain critical thickness small in comparison with the outer radius of the system, as a result of a local gravitational collapse the nebula disintegrated into the central body ("protosun") and a number of separate protoplanets. The massive gas and dust solar nebula of solar composition is considered, and the gasdynamic theory is used to study the gravitational instability in its protoplanetary disk. The implications for the origin of the solar system are discussed. It is suggested that the large part of the initial mass of protoplanets of the Earth's group was blown away due to intensive thermal emission of the early Sun. Such a point of view is not unnatural since the planets of the Earth's type consist mainly of elements with a high melting temperature and are almost lacking light elements. By adding to the present masses of the terrestrial planets the amount of light gases which is necessary to restore the chemical composition of giant planets, one obtains masses larger by a factor of several hundreds, coincident with the masses of giant planets. We show that a collective process, forming the basis of the disk instability hypothesis, solves with surprising simplicity the two main problems of the dynamical characteristics of the system, which are associated with its observed spacing and orbital momentum distribution, namely, Bode's law on planet spacing and the concentration of angular momentum in the planets and mass in the Sun. Besides, the analysis is found to imply the existence of new planets or other Kuiper-type belts of asteroids at mean distances from the Sun of r11 ≈ 87 AU, r12 ≈ 151 AU, r13 ≈ 261 AU, r14 ≈ 452 AU, r15 ≈ 781 AU (Mercury, . . . , asteroid belt, . . . , Neptune, Kuiper belt, new planets or other Kuiper-type belts). Finally, it is suggested that solar systems analogs may be common throughout the Galaxy.

A kinetic study of solar wind electrons in the transition region from collision dominated to collisionless flow

NASA Technical Reports Server (NTRS)

Lie-Svendsen, O.; Leer, E.

1995-01-01

We have studied the evolution of the velocity distribution function of a test population of electrons in the solar corona and inner solar wind region, using a recently developed kinetic model. The model solves the time dependent, linear transport equation, with a Fokker-Planck collision operator to describe Coulomb collisions between the 'test population' and a thermal background of charged particles, using a finite differencing scheme. The model provides information on how non-Maxwellian features develop in the distribution function in the transition region from collision dominated to collisionless flow. By taking moments of the distribution the evolution of higher order moments, such as the heat flow, can be studied.

Modeling and analysis of solar distributed generation

NASA Astrophysics Data System (ADS)

Ortiz Rivera, Eduardo Ivan

Recent changes in the global economy are creating a big impact in our daily life. The price of oil is increasing and the number of reserves are less every day. Also, dramatic demographic changes are impacting the viability of the electric infrastructure and ultimately the economic future of the industry. These are some of the reasons that many countries are looking for alternative energy to produce electric energy. The most common form of green energy in our daily life is solar energy. To convert solar energy into electrical energy is required solar panels, dc-dc converters, power control, sensors, and inverters. In this work, a photovoltaic module, PVM, model using the electrical characteristics provided by the manufacturer data sheet is presented for power system applications. Experimental results from testing are showed, verifying the proposed PVM model. Also in this work, three maximum power point tracker, MPPT, algorithms would be presented to obtain the maximum power from a PVM. The first MPPT algorithm is a method based on the Rolle's and Lagrange's Theorems and can provide at least an approximate answer to a family of transcendental functions that cannot be solved using differential calculus. The second MPPT algorithm is based on the approximation of the proposed PVM model using fractional polynomials where the shape, boundary conditions and performance of the proposed PVM model are satisfied. The third MPPT algorithm is based in the determination of the optimal duty cycle for a dc-dc converter and the previous knowledge of the load or load matching conditions. Also, four algorithms to calculate the effective irradiance level and temperature over a photovoltaic module are presented in this work. The main reasons to develop these algorithms are for monitoring climate conditions, the elimination of temperature and solar irradiance sensors, reductions in cost for a photovoltaic inverter system, and development of new algorithms to be integrated with maximum power point tracking algorithms. Finally, several PV power applications will be presented like circuit analysis for a load connected to two different PV arrays, speed control for a do motor connected to a PVM, and a novel single phase photovoltaic inverter system using the Z-source converter.

Young Stars in Orion May Solve Mystery of Our Solar System

NASA Astrophysics Data System (ADS)

2001-09-01

Scientists may have to give the Sun a little more credit. Exotic isotopes present in the early Solar System--which scientists have long-assumed were sprinkled there by a powerful, nearby star explosion--may have instead been forged locally by our Sun during the colossal solar-flare tantrums of its baby years. The isotopes--special forms of atomic nuclei, such as aluminum-26, calcium-41, and beryllium-10--can form in the X-ray solar flares of young stars in the Orion Nebula, which behave just like our Sun would have at such an early age. The finding, based on observations by the Chandra X-ray Observatory, has broad implications for the formation of our own Solar System. Eric Feigelson, professor of astronomy and astrophysics at Penn State, led a team of scientists on this Chandra observation and presents these results in Washington, D.C., today at a conference entitled "Two Years of Science with Chandra". "The Chandra study of Orion gives us the first chance to study the flaring properties of stars resembling the Sun when our solar system was forming," said Feigelson. "We found a much higher rate of flares than expected, sufficient to explain the production of many unusual isotopes locked away in ancient meteorites. If the young stars in Orion can do it, then our Sun should have been able to do it too." Scientists who study how our Solar System formed from a collapsed cloud of dust and gas have been hard pressed to explain the presence of these extremely unusual chemical isotopes. The isotopes are short-lived and had to have been formed no earlier than the creation of the Solar System, some five billion years ago. Yet these elements cannot be produced by a star as massive as our Sun under normal circumstances. (Other elements, such as silver and gold, were created long before the creation of the solar system.) The perplexing presence of these isotopic anomalies, found in ancient meteoroids orbiting the Earth, led to the theory that a supernova explosion occurred very close to the Solar System's progenitor gas cloud, simultaneously triggering its collapse and seeding it with short-lived isotopes. Solar flares could produce such isotopes, but the flares would have to be hundreds of thousands of times more powerful and hundreds of times more frequent than those our Sun generates. Enter the stars in the Orion Nebula. This star-forming region has several dozen new stars nearly identical to our Sun, only much younger. Feigelson's team used Chandra to study the flaring in these analogs of the early Sun and found that nearly all exhibit extremely high levels of X-ray flaring--powerful and frequent enough to forge many of the kinds of isotopes found in the ancient meteorites from the early solar system. "This is a very exciting result for space X-ray astronomy," said Donald Clayton, Centennial Professor of Physics and Astronomy at Clemson University. "The Chandra Penn State team has shown that stellar-flare acceleration produces radioactive nuclei whether we want them or not. Now the science debate can concentrate on whether such irradiation made some or even all of the extinct radioactivities that were present when our solar system was formed, or whether some contamination of our birth molecular cloud by external material is also needed." "This is an excellent example of how apparently distant scientific fields, like X-ray astronomy and the origins of solar systems, can in fact be closely linked," said Feigelson. The Orion observation was made with Chandra's Advanced CCD Imaging Spectrometer, which was conceived and developed for NASA by Penn State and Massachusetts Institute of Technology under the leadership of Gordon Garmire, the Evan Pugh Professor of Astronomy and Astrophysics at Penn State. The Penn State observation team includes Pat Broos, James Gaffney, Gordon Garmire, Leisa Townsley and Yohko Tsuboi. Collaborators also include Lynne Hillenbrand of CalTech and Steven Pravdo of the NASA Jet Propulsion Laboratory. Background: Isotopes are atoms whose nuclei have different numbers of neutrons. Many isotopes are unstable, or radioactive, and decay into other elements. A famous example is carbon-14 whose decay gives scientists the opportunity to date organic materials over thousands of years. A rare type of ancient meteorite called carbonaceous chondrites, which are rocks from the Asteroid Belt whose orbits are perturbed and fall to the Earth, date back to the formation of our Solar System 4.55 billion years ago. Studying carbonaceous chondrites gives us a unique window on conditions in the solar nebula when the Sun and Solar System were forming. Certain portions of carbonaceous chondrites, small melted pebbles called Calcium-Aluminum-rich Inclusions or CAIs, have unusually high abundances of decay products of rare, short-lived isotopes. These include beryllium-10, calcium-41, 26-aluminum and 53-manganese, among others. Explaining the presence of these short-lived isotopes, which do not appear anywhere else in solar system material, has been one of the toughest challenges of solar system science. The favored explanation has been that a star exploded in a supernova and triggered a nearby cloud of dust and gas to collapse to form our Sun and planetary system. But conditions have to be carefully adjusted for this model, and it cannot be widely applied to all stars. The principal alternative model is that energetic particles from violent flares hit particles in the solar nebula and transformed some of their atoms to radioactive isotopes. A drawback to this model has been that the level of flaring needed, around 100,000 times the flaring level of the Sun today, was thought to be impossibly high. However, the X-ray observations reported here give direct evidence for just this high level of flaring. In addition, this model readily applied to all young stars and solar systems, not just a few.

Women Working in Engineering and Science

NASA Technical Reports Server (NTRS)

Luna, Bernadette; Kliss, Mark (Technical Monitor)

1998-01-01

The presentation will focus on topics of interest to young women pursuing an engineering or scientific career, such as intrinsic personality traits of most engineers, average salaries for the various types of engineers, appropriate preparation classes at the high school and undergraduate levels, gaining experience through internships, summer jobs and graduate school, skills necessary but not always included in engineering curricula (i.e., multimedia, computer skills, communication skills), the work environment, balancing family and career, and sexual harassment. Specific examples from the speaker's own experience in NASA's Space Life Sciences Program will be used to illustrate the above topics. In particular, projects from Extravehicular Activity and Protective Systems research and Regenerative Life Support research will be used as examples of real world problem-solving to enable human exploration of the solar system.

Interstellar Flight, Imagination and Myth Creation as an Effective Means for Enduring Inspiration

NASA Astrophysics Data System (ADS)

Padowitz, G. H.

Interstellar travel to faraway star systems is humanity's most crucial mission, but we habitually focus on technological and funding challenges instead of deeply exploring the rare essence of creativity that is the source that enables us to ultimately solve all problems. Certainly, if Interstellar space flight is to succeed, inspiring and maintaining global and multigenerational support is primary to long-term development. To attract and sustain such extraordinary support the creative power of the imagination must be harnessed through independent artists. By first attracting and encouraging visionaries it's possible that we can awaken in the public a new, invigorating sense of adventure with lasting power. Going beyond our solar system to a nearby star is in reality a mythic quest and should be treated as such.

The use of solar energy for residential buildings in the capital city

NASA Astrophysics Data System (ADS)

Velkin, V.; Shcheklein, S.; Danilov, V.

2017-06-01

Taking into account the conditions of sharply continental climate of Russia the implementation of the project of heating for an apartment house can be structured on the basis of solar vacuum collectors. A diagram of the operation of the vacuum solar collectors can be considered for heating and hot water. The calculations of effective angle of solar collectors also vary for stationary use in winter and summer. Consumption of centralized heat in the spring and autumn is reduced by 30 % due to the use of solar collectors. In summer the main problem of application of solar collectors is to protect the tubes from overheating. In winter, the use of solar heating is able to provide not more than 25 % of the needs regarding the utility and the results of experimental exploitation. It is shown that the main problem of using solar energy in Russia relies not in technology, but in the legislative field. The use of a vacuum manifold in Russia will be widely implemented in areas with a cold climate and in the modern houses after solving the issues of legislative support from the state and municipal authorities.

Accretion Disks around Young Stars: An Observational Perspective

NASA Astrophysics Data System (ADS)

Ménard, F.; Bertout, C.

Accretion disks are pivotal elements in the formation and early evolution of solar-like stars. On top of supplying the raw material, their internal conditions also regulate the formation of planets. Their study therefore holds the key to solve this long standing mystery: how did our Solar System form? This chapter focuses on observational studies of the circumstellar environment, and in particular of circumstellar disks, associated with pre-main sequence solar-like stars. The direct measurement of disk parameters poses an obvious challenge: at the distance of the typical star forming regions ( e.g. 140 pc for Taurus), a planetary system like ours (with diameter simeq50 AU out to Pluto, but excluding the Kuiper belt which could extend much farther out) subtends only 0.35''. Yet its surface brightness is low in comparison to the bright central star and high angular and high contrast imaging techniques are required if one hopes to resolve and measure these protoplanetary disks. Fortunately, capable instruments providing 0.1'' resolution or better and high contrast have been available for just about 10 years now. They are covering a large part of the electromagnetic spectrum, from the UV/Optical with HST and the near-infrared from ground-based adaptive optics systems, to the millimetric range with long-baseline radio interferometers. It is therefore not surprising that our knowledge of the structure of the disks surrounding low-mass stars has made a gigantic leap forward in the last decade. In the following pages we will attempt to describe, in a historical perpective, the road that led to the idea that most solar-like stars are surrounded by an accretion disk at one point in their early life and how, nowadays, their structural and physical parameters can be estimated from direct observations. We will follow by a short discussion of a few of the constraints available regarding the evolution and dissipation of these disks. This last topic is particularly relevant today to understand the mechanism leading to the formation of planets.

Orbital theory in terms of KS elements with luni-solar perturbations

NASA Astrophysics Data System (ADS)

Sellamuthu, Harishkumar; Sharma, Ram

2016-07-01

Precise orbit computation of Earth orbiting satellites is essential for efficient mission planning of planetary exploration, navigation and satellite geodesy. The third-body perturbations of the Sun and the Moon predominantly affect the satellite motion in the high altitude and elliptical orbits, where the effect of atmospheric drag is negligible. The physics of the luni-solar gravity effect on Earth satellites have been studied extensively over the years. The combined luni-solar gravitational attraction will induce a cumulative effect on the dynamics of satellite orbits, which mainly oscillates the perigee altitude. Though accurate orbital parameters are computed by numerical integration with respect to complex force models, analytical theories are highly valued for the manifold of solutions restricted to relatively simple force models. During close approach, the classical equations of motion in celestial mechanics are almost singular and they are unstable for long-term orbit propagation. A new singularity-free analytical theory in terms of KS (Kustaanheimo and Stiefel) regular elements with respect to luni-solar perturbation is developed. These equations are regular everywhere and eccentric anomaly is the independent variable. Plataforma Solar de Almería (PSA) algorithm and a Fourier series algorithm are used to compute the accurate positions of the Sun and the Moon, respectively. Numerical studies are carried out for wide range of initial parameters and the analytical solutions are found to be satisfactory when compared with numerically integrated values. The symmetrical nature of the equations allows only two of the nine equations to be solved for computing the state vectors and the time. Only a change in the initial conditions is required to solve the other equations. This theory will find multiple applications including on-board software packages and for mission analysis purposes.

Multi-Fluid Simulations of a Coupled Ionosphere-Magnetosphere System

NASA Astrophysics Data System (ADS)

Gombosi, T. I.; Glocer, A.; Toth, G.; Ridley, A. J.; Sokolov, I. V.; de Zeeuw, D. L.

2008-05-01

In the last decade we have developed the Space Weather Modeling Framework (SWMF) that efficiently couples together different models describing the interacting regions of the space environment. Many of these domain models (such as the global solar corona, the inner heliosphere or the global magnetosphere) are based on MHD and are represented by our multiphysics code, BATS-R-US. BATS-R-US can solve the equations of "standard" ideal MHD, but it can also go beyond this first approximation. It can solve resistive MHD, Hall MHD, semi-relativistic MHD (that keeps the displacement current), multispecies (different ion species have different continuity equations) and multifluid (all ion species have separate continuity, momentum and energy equations) MHD. Recently we added two-fluid Hall MHD (solving the electron and ion energy equations separately) and are working on an extended magnetohydrodynamics model with anisotropic pressures. Ionosheric outflow can be a significant contributor to the plasma population of the magnetosphere during active geomagnetic conditions. This talk will present preliminary results of our simulations when we couple a new field- aligned multi-fluid polar wind code to the Ionosphere Electrodynamics (IE), and Global Magnetosphere (GM) components of the SWMF. We use multi-species and multi-fluid MHD to track the resulting plasma composition in the magnetosphere.

Doing Solar Science With Extreme-ultraviolet and X-ray High Resolution Imaging Spectroscopy

NASA Astrophysics Data System (ADS)

Doschek, G. A.

2005-12-01

In this talk I will demonstrate how high resolution extreme-ultraviolet (EUV) and/or X-ray imaging spectroscopy can be used to provide unique information for solving several current key problems of the solar atmosphere, e.g., the morphology and reconnection site of solar flares, the structure of the transition region, and coronal heating. I will describe the spectra that already exist relevant to these problems and what the shortcomings of the data are, and how an instrument such as the Extreme-ultraviolet Imaging Spectrometer (EIS) on Solar-B as well as other proposed spectroscopy missions such as NEXUS and RAM will improve on the existing observations. I will discuss a few particularly interesting properties of the spectra and atomic data for highly ionized atoms that are important for the science problems.

Multi-physics simulations of space weather

NASA Astrophysics Data System (ADS)

Gombosi, Tamas; Toth, Gabor; Sokolov, Igor; de Zeeuw, Darren; van der Holst, Bart; Cohen, Ofer; Glocer, Alex; Manchester, Ward, IV; Ridley, Aaron

Presently magnetohydrodynamic (MHD) models represent the "workhorse" technology for simulating the space environment from the solar corona to the ionosphere. While these models are very successful in describing many important phenomena, they are based on a low-order moment approximation of the phase-space distribution function. In the last decade our group at the Center for Space Environment Modeling (CSEM) has developed the Space Weather Modeling Framework (SWMF) that efficiently couples together different models describing the interacting regions of the space environment. Many of these domain models (such as the global solar corona, the inner heliosphere or the global magnetosphere) are based on MHD and are represented by our multiphysics code, BATS-R-US. BATS-R-US can solve the equations of "standard" ideal MHD, but it can also go beyond this first approximation. It can solve resistive MHD, Hall MHD, semi-relativistic MHD (that keeps the displacement current), multispecies (different ion species have different continuity equations) and multifluid (all ion species have separate continuity, momentum and energy equations) MHD. Recently we added two-fluid Hall MHD (solving the electron and ion energy equations separately) and are working on extended magnetohydrodynamics with anisotropic pressures. This talk will show the effects of added physics and compare space weather simulation results to "standard" ideal MHD.

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.

The design of visualization telemetry system based on camera module of the commercial smartphone

NASA Astrophysics Data System (ADS)

Wang, Chao; Ye, Zhao; Wu, Bin; Yin, Huan; Cao, Qipeng; Zhu, Jun

2017-09-01

Satellite telemetry is the vital indicators to estimate the performance of the satellite. The telemetry data, the threshold range and the variation tendency collected during the whole operational life of the satellite, can guide and evaluate the subsequent design of the satellite in the future. The rotational parts on the satellite (e.g. solar arrays, antennas and oscillating mirrors) affect collecting the solar energy and the other functions of the satellite. Visualization telemetries (pictures, video) are captured to interpret the status of the satellite qualitatively in real time as an important supplement for troubleshooting. The mature technology of commercial off-the-shelf (COTS) products have obvious advantages in terms of the design of construction, electronics, interfaces and image processing. Also considering the weight, power consumption, and cost, it can be directly used in our application or can be adopted for secondary development. In this paper, characteristic simulations of solar arrays radiation in orbit are presented, and a suitable camera module of certain commercial smartphone is adopted after the precise calculation and the product selection process. Considering the advantages of the COTS devices, which can solve both the fundamental and complicated satellite problems, this technique proposed is innovative to the project implementation in the future.

Influence of upstream solar wind on thermospheric flows at Jupiter

NASA Astrophysics Data System (ADS)

Yates, J. N.; Achilleos, N.; Guio, P.

2012-02-01

The coupling of Jupiter's magnetosphere and ionosphere plays a vital role in creating its auroral emissions. The strength of these emissions is dependent on the difference in speed of the rotational flows within Jupiter's high-latitude thermosphere and the planet's magnetodisc. Using an azimuthally symmetric global circulation model, we have simulated how upstream solar wind conditions affect the energy and direction of atmospheric flows. In order to simulate the effect of a varying dynamic pressure in the upstream solar wind, we calculated three magnetic field profiles representing compressed, averaged and expanded ‘middle’ magnetospheres. These profiles were then used to solve for the angular velocity of plasma in the magnetosphere. This angular velocity determines the strength of currents flowing between the ionosphere and magnetosphere. We examine the influence of variability in this current system upon the global winds and energy inputs within the Jovian thermosphere. We find that the power dissipated by Joule heating and ion drag increases by ∼190% and ∼185% from our compressed to expanded model respectively. We investigated the effect of exterior boundary conditions on our models and found that by reducing the radial current at the outer edge of the magnetodisc, we also limit the thermosphere's ability to transmit angular momentum to this region.

The combined value of wind and solar power forecasting improvements and electricity storage

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

Hodge, Bri-Mathias; Brancucci Martinez-Anido, Carlo; Wang, Qin

As the penetration rates of variable renewable energy increase, the value of power systems operation flexibility technology options, such as renewable energy forecasting improvements and electricity storage, is also assumed to increase. In this work, we examine the value of these two technologies, when used independently and concurrently, for two real case studies that represent the generation mixes for the California and Midcontinent Independent System Operators (CAISO and MISO). Since both technologies provide additional system flexibility they reduce operational costs and renewable curtailment for both generation mixes under study. Interestingly, the relative impacts are quite similar when both technologies aremore » used together. Though both flexibility options can solve some of the same issues that arise with high penetration levels of renewables, they do not seem to significantly increase or decrease the economic potential of the other technology.« less

The combined value of wind and solar power forecasting improvements and electricity storage

DOE PAGES

Hodge, Bri-Mathias; Brancucci Martinez-Anido, Carlo; Wang, Qin; ...

2018-02-12

As the penetration rates of variable renewable energy increase, the value of power systems operation flexibility technology options, such as renewable energy forecasting improvements and electricity storage, is also assumed to increase. In this work, we examine the value of these two technologies, when used independently and concurrently, for two real case studies that represent the generation mixes for the California and Midcontinent Independent System Operators (CAISO and MISO). Since both technologies provide additional system flexibility they reduce operational costs and renewable curtailment for both generation mixes under study. Interestingly, the relative impacts are quite similar when both technologies aremore » used together. Though both flexibility options can solve some of the same issues that arise with high penetration levels of renewables, they do not seem to significantly increase or decrease the economic potential of the other technology.« less

The design and evaluation of grazing incidence relay optics

NASA Technical Reports Server (NTRS)

Davis, John M.; Chase, R. C.; Silk, J. K.; Krieger, A. S.

1989-01-01

X-ray astronomy, both solar and celestial, has many needs for high spatial resolution observations which have to be performed with electronic detectors. If the resolution is not to be detector limited, plate scales in excess of 25 microns arc/sec, corresponding to focal lengths greater than 5 m, are required. In situations where the physical size is restricted, the problem can be solved by the use of grazing incidence relay optics. A system was developed which employs externally polished hyperboloid-hyperboloid surfaces to be used in conjunction with a Wolter-Schwarzschild primary. The secondary is located in front of the primary focus and provides a magnification of 4, while the system has a plate scale of 28 microns arc/sec and a length of 1.9 m. The design, tolerance specification, fabrication and performance at visible and X-ray wavelengths of this optical system are described.

Thermally induced vibrations of smart solar panel in a low-orbit satellite

NASA Astrophysics Data System (ADS)

Azadi, E.; Fazelzadeh, S. Ahmad; Azadi, M.

2017-03-01

In this paper, a smart flexible satellite moving in a circular orbit with two flexible panels are studied. The panels have been modeled as clamped-free-free-free rectangular plates with attached piezoelectric actuators. It is assumed that the satellite has a pitch angle rotation maneuver. Rapid temperature changes at day-night transitions in orbit generate time dependent bending moments. Satellite maneuver and temperature varying induce vibrations in the appendages. So, to simulate the system, heat radiation effects on the appendages have been considered. The nonlinear equations of motion and the heat transfer equations are coupled and solved simultaneously. So, the governing equations of motion are nonlinear and very complicated ones. Finally, the whole system is simulated and the effects of the heat radiation, radius of the orbit, piezoelectric voltages, and piezoelectric locations on the response of the system are studied.

MHD Modeling of the Solar Wind with Turbulence Transport and Heating

NASA Technical Reports Server (NTRS)

Goldstein, M. L.; Usmanov, A. V.; Matthaeus, W. H.; Breech, B.

2009-01-01

We have developed a magnetohydrodynamic model that describes the global axisymmetric steady-state structure of the solar wind near solar minimum with account for transport of small-scale turbulence associated heating. The Reynolds-averaged mass, momentum, induction, and energy equations for the large-scale solar wind flow are solved simultaneously with the turbulence transport equations in the region from 0.3 to 100 AU. The large-scale equations include subgrid-scale terms due to turbulence and the turbulence (small-scale) equations describe the effects of transport and (phenomenologically) dissipation of the MHD turbulence based on a few statistical parameters (turbulence energy, normalized cross-helicity, and correlation scale). The coupled set of equations is integrated numerically for a source dipole field on the Sun by a time-relaxation method in the corotating frame of reference. We present results on the plasma, magnetic field, and turbulence distributions throughout the heliosphere and on the role of the turbulence in the large-scale structure and temperature distribution in the solar wind.

Effects of Mg II and Ca II ionization on ab-initio solar chromosphere models

NASA Technical Reports Server (NTRS)

Rammacher, W.; Cuntz, M.

1991-01-01

Acoustically heated solar chromosphere models are computed considering radiation damping by (non-LTE) emission from H(-) and by Mg II and Ca II emission lines. The radiative transfer equations for the Mg II k and Ca II K emission lines are solved using the core-saturation method with complete redistribution. The Mg II k and Ca II K cooling rates are compared with the VAL model C. Several substantial improvements over the work of Ulmschneider et al. (1987) are included. It is found that the rapid temperature rises caused by the ionization of Mg II are not formed in the middle chromosphere, but occur at larger atmospheric heights. These models represent the temperature structure of the 'real' solar chromosphere much better. This result is a major precondition for the study of ab-initio models for solar flux tubes based on MHD wave propagation and also for ab-initio models for the solar transition layer.

Dynamo generation of magnetic fields in three-dimensional space - Solar cycle main flux tube formation and reversals

NASA Astrophysics Data System (ADS)

Yoshimura, H.

1983-08-01

The case of the solar magnetic cycle is investigated as a prototype of the dynamo processes involved in the generation of magnetic fields in astrophysics. Magnetohydrodynamic (MHD) equations are solved using a numerical method with a prescribed velocity field in order follow the movement and deformation. It is shown that a simple combination of differential rotation and global convection, given by a linear analysis of fluid dynamics in a rotating sphere, can perpetually create and reverse great magnetic flux tubes encircling the sun. These main flux tubes of the solar cycle are the progenitors of small-scale flux ropes of the solar activity. These findings indicate that magnetic fields can be generated by fluid motions and that MHD equations have a new type of oscillatory solution. It is shown that the solar cycle can be identified with one of these oscillatory solutions. It is proposed that the formation of magnetic flux tubes by streaming plasma flows is a universal mechanism of flux tube formation in astrophysics.

Platinum Alloy Tailored All-Weather Solar Cells for Energy Harvesting from Sun and Rain.

PubMed

Tang, Qunwei; Duan, Yanyan; He, Benlin; Chen, Haiyan

2016-11-07

Solar cells that can harvest energy in all weathers are promising in solving the energy crisis and environmental problems. The power outputs are nearly zero under dark conditions for state-of-the-art solar cells. To address this issue, we present herein a class of platinum alloy (PtM x , M=Ni, Fe, Co, Cu, Mo) tailored all-weather solar cells that can harvest energy from rain and realize photoelectric conversion under sun illumination. By tuning the stoichiometric Pt/M ratio and M species, the optimized solar cell yields a photoelectric conversion efficiency of 10.38 % under simulated sunlight irradiation (AM 1.5, 100 mW cm -2 ) as well as current of 3.90 μA and voltage of 115.52 μV under simulated raindrops. Moreover, the electric signals are highly dependent on the dripping velocity and the concentration of simulated raindrops along with concentrations of cation and anion. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

A parameter study of the two-fluid solar wind

NASA Technical Reports Server (NTRS)

Sandbaek, Ornulf; Leer, Egil; Holzer, Thomas E.

1992-01-01

A two-fluid model of the solar wind was introduced by Sturrock and Hartle (1966) and Hartle and Sturrock (1968). In these studies the proton energy equation was integrated neglecting the heat conductive term. Later several authors solved the equations for the two-fluid solar wind model keeping the proton heat conductive term. Methods where the equations are integrated simultaneously outward and inward from the critical point were used. The equations were also integrated inward from a large heliocentric distance. These methods have been applied to cases with low coronal base electron densities and high base temperatures. In this paper we present a method of integrating the two-fluid solar wind equations using an iteration procedure where the equations are integrated separately and the proton flux is kept constant during the integrations. The technique is applicable for a wide range of coronal base densities and temperatures. The method is used to carry out a parameter study of the two-fluid solar wind.

Efficient full-spectrum utilization, reception and conversion of solar energy by broad-band nanospiral antenna.

PubMed

Zhao, Huaqiao; Gao, Huotao; Cao, Ting; Li, Boya

2018-01-22

In this work, the collection of solar energy by a broad-band nanospiral antenna is investigated in order to solve the low efficiency of the solar rectenna based on conventional nanoantennas. The antenna impedance, radiation, polarization and effective area are all considered in the efficiency calculation using the finite integral technique. The wavelength range investigated is 300-3000 nm, which corresponds to more than 98% of the solar radiation energy. It's found that the nanospiral has stronger field enhancement in the gap than a nanodipole counterpart. And a maximum harvesting efficiency about 80% is possible in principle for the nanospiral coupled to a rectifier resistance of 200 Ω, while about 10% for the nanodipole under the same conditions. Moreover, the nanospiral could be coupled to a rectifier diode of high resistance more easily than the nanodipole. These results indicate that the efficient full-spectrum utilization, reception and conversion of solar energy can be achieved by the nanospiral antenna, which is expected to promote the solar rectenna to be a promising technology in the clean, renewable energy application.

A MODEL OF MAGNETIC BRAKING OF SOLAR ROTATION THAT SATISFIES OBSERVATIONAL CONSTRAINTS

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

Denissenkov, Pavel A., E-mail: pavel.denisenkov@gmail.co

The model of magnetic braking of solar rotation considered by Charbonneau and MacGregor has been modified so that it is able to reproduce for the first time the rotational evolution of both the fastest and slowest rotators among solar-type stars in open clusters of different ages, without coming into conflict with other observational constraints, such as the time evolution of the atmospheric Li abundance in solar twins and the thinness of the solar tachocline. This new model assumes that rotation-driven turbulent diffusion, which is thought to amplify the viscosity and magnetic diffusivity in stellar radiative zones, is strongly anisotropic withmore » the horizontal components of the transport coefficients strongly dominating over those in the vertical direction. Also taken into account is the poloidal field decay that helps to confine the width of the tachocline at the solar age. The model's properties are investigated by numerically solving the azimuthal components of the coupled momentum and magnetic induction equations in two dimensions using a finite element method.« less

Solar electricity supply isolines of generation capacity and storage.

PubMed

Grossmann, Wolf; Grossmann, Iris; Steininger, Karl W

2015-03-24

The recent sharp drop in the cost of photovoltaic (PV) electricity generation accompanied by globally rapidly increasing investment in PV plants calls for new planning and management tools for large-scale distributed solar networks. Of major importance are methods to overcome intermittency of solar electricity, i.e., to provide dispatchable electricity at minimal costs. We find that pairs of electricity generation capacity G and storage S that give dispatchable electricity and are minimal with respect to S for a given G exhibit a smooth relationship of mutual substitutability between G and S. These isolines between G and S support the solving of several tasks, including the optimal sizing of generation capacity and storage, optimal siting of solar parks, optimal connections of solar parks across time zones for minimizing intermittency, and management of storage in situations of far below average insolation to provide dispatchable electricity. G-S isolines allow determining the cost-optimal pair (G,S) as a function of the cost ratio of G and S. G-S isolines provide a method for evaluating the effect of geographic spread and time zone coverage on costs of solar electricity.

Solar electricity supply isolines of generation capacity and storage

PubMed Central

Grossmann, Wolf; Grossmann, Iris; Steininger, Karl W.

2015-01-01

The recent sharp drop in the cost of photovoltaic (PV) electricity generation accompanied by globally rapidly increasing investment in PV plants calls for new planning and management tools for large-scale distributed solar networks. Of major importance are methods to overcome intermittency of solar electricity, i.e., to provide dispatchable electricity at minimal costs. We find that pairs of electricity generation capacity G and storage S that give dispatchable electricity and are minimal with respect to S for a given G exhibit a smooth relationship of mutual substitutability between G and S. These isolines between G and S support the solving of several tasks, including the optimal sizing of generation capacity and storage, optimal siting of solar parks, optimal connections of solar parks across time zones for minimizing intermittency, and management of storage in situations of far below average insolation to provide dispatchable electricity. G−S isolines allow determining the cost-optimal pair (G,S) as a function of the cost ratio of G and S. G−S isolines provide a method for evaluating the effect of geographic spread and time zone coverage on costs of solar electricity. PMID:25755261

Cosmic Ray Modulation and Radiation Dose of Aircrews During Possible Grand Minimum

NASA Astrophysics Data System (ADS)

Miyake, S.; Kataoka, R.; Sato, T.; Imada, S.; Miyahara, H.; Shiota, D.; Matsumoto, T.; Ueno, H.

2017-12-01

The Sun is exhibiting low solar activity levels since the descending phase of the last solar cycle, and it is likely to be continued as well as in the case of the past grand solar minima. The cosmic-ray modulation, which is the variation of the galactic cosmic ray (GCR) spectrum caused by the heliospheric environmental change, is basically anti-correlated with the solar activity. In the recent weak solar cycle, we thus expect that the flux of GCRs is getting higher than that in the previous solar cycles, leading to the increase in the radiation exposure in the space and atmosphere. In order to quantitatively evaluate the possible solar modulation of GCRs and resultant radiation exposure at flight altitude, we have developed the time-dependent and three-dimensional model of the cosmic-ray modulation. Our model can give the flux of GCRs anywhere in the heliosphere by assuming the variation of the solar wind speed, the strength of the heliospheric magnetic field (HMF), and its tilt angle. We solve the gradient-curvature drift motion of GCRs in the HMF, and therefore reproduce the 22-year variation of the cosmic-ray modulation. We also calculate the neutron monitor counting rate and the radiation dose of aircrews at flight altitude, by the air-shower simulation performed by PHITS (Particle and Heavy Ion Transport code System). In our previous study [1], we calculated the radiation dose at a flight altitude during the coming solar cycle by assuming the variation of the solar wind speed and the strength of the HMF expressed by sinusoidal curve, and obtained that an annual radiation dose of aircrews in 5 years around the next solar minimum will be up to 19% higher than that at the last cycle. In this study, we predict the new model of the heliospheric environmental change on the basis of a prediction model for the sunspot number. The quantitative predictions of the cosmic-ray modulation and the radiation dose at a flight altitude during possible Grand Minimum considering the new model for the heliospheric environmental change will be presented at the meeting. [1] S. Miyake, R. Kataoka, and T. Sato, Space Weather, 15, 589-605, 2017.

The Formation of the Solar System: Theories Old and New

NASA Astrophysics Data System (ADS)

Woolfson, Michael

ch. 1. Theories come and theories go -- ch. 2. Measuring atoms and the universe -- ch. 3. Greek offerings -- ch. 4. The shoulders of giants -- ch. 5. A voyage of discovery to the solar system -- ch. 6. The problem to be solved -- ch. 7. The French connection -- ch. 8. American Catherine-Wheels -- ch. 9. British big tides -- ch. 10. Russian could capture-with British help -- ch. 11. German vortices-with a little French help -- ch. 12. McCrea's floccules -- ch. 13. What earlier theories indicate -- ch. 14. Disks around new stars -- ch. 15. Planets around other stars -- ch. 16. Disks around older stars -- ch. 17. What a theory should explain now -- ch. 18. The new Solar Nebula theory: the angular momentum problem -- ch. 19. Making planets top-down -- ch. 20. A bottom-up alternative -- ch. 21. Making planets faster -- ch. 22. Wandering planets -- ch. 23. Back to top-down -- ch. 24. This is the stuff that stars are made of -- ch. 25. Making dense cool clouds -- ch. 26. A star is born -- ch. 27. Close to the maddening crowd -- ch. 28. Close encounters of the stellar kind -- ch. 29. Ever decreasing circles -- ch. 30. How many planetary systems? -- ch. 31. Starting a family -- ch. 32. Tilting-but not as windmills -- ch. 33. The terrestrial planets raise problems! -- ch. 34. A British Bang theory: the earth and Venus -- ch. 35. Behold the wandering moon -- ch. 36. Fleet Mercury and warlike Mars -- ch. 37. Gods of the sea and the nether regions -- ch. 38. Bits and pieces -- ch. 39. Comets-the harbingers of doom! -- ch. 40. Making atoms with a biggish bang -- ch. 41. Is the capture theory valid?

Atmospheric Electricity

NASA Astrophysics Data System (ADS)

Aplin, Karen; Fischer, Georg

2018-02-01

Electricity occurs in atmospheres across the Solar System planets and beyond, spanning spectacular lightning displays in clouds of water or dust, to more subtle effects of charge and electric fields. On Earth, lightning is likely to have existed for a long time, based on evidence from fossilized lightning strikes in ancient rocks, but observations of planetary lightning are necessarily much more recent. The generation and observations of lightning and other atmospheric electrical processes, both from within-atmosphere measurements, and spacecraft remote sensing, can be readily studied using a comparative planetology approach, with Earth as a model. All atmospheres contain charged molecules, electrons, and/or molecular clusters created by ionization from cosmic rays and other processes, which may affect an atmosphere's energy balance both through aerosol and cloud formation, and direct absorption of radiation. Several planets are anticipated to host a "global electric circuit" by analogy with the circuit occurring on Earth, where thunderstorms drive current of ions or electrons through weakly conductive parts of the atmosphere. This current flow may further modulate an atmosphere's radiative properties through cloud and aerosol effects. Lightning could potentially have implications for life through its effects on atmospheric chemistry and particle transport. It has been observed on many of the Solar System planets (Earth, Jupiter, Saturn, Uranus, and Neptune) and it may also be present on Venus and Mars. On Earth, Jupiter, and Saturn, lightning is thought to be generated in deep water and ice clouds, but discharges can be generated in dust, as for terrestrial volcanic lightning, and on Mars. Other, less well-understood mechanisms causing discharges in non-water clouds also seem likely. The discovery of thousands of exoplanets has recently led to a range of further exotic possibilities for atmospheric electricity, though lightning detection beyond our Solar System remains a technical challenge to be solved.

Mapping the Solar System with LSST

NASA Astrophysics Data System (ADS)

Ivezic, Z.; Juric, M.; Lupton, R.; Connolly, A.; Kubica, J.; Moore, A.; Harris, A.; Bowell, T.; Bernstein, G.; Stubbs, C.; LSST Collaboration

2004-12-01

The currently considered LSST cadence, based on two 10 sec exposures, may result in orbital parameters, light curves and accurate colors for over a million main-belt asteroids (MBA), and about 20,000 trans-Neptunian objects (TNO). Compared to the current state-of-the-art, this sample would represent a factor of 5 increase in the number of MBAs with known orbits, a factor of 20 increase in the number of MBAs with known orbits and accurate color measurements, and a factor of 100 increase in the number of MBAs with measured variability properties. The corresponding sample increase for TNOs is 10, 100, and 1000, respectively. The LSST MBA and TNO samples will enable detailed studies of the dynamical and chemical history of the solar system. For example, they will constrain the MBA size distribution for objects larger than 100 m, and TNO size distribution for objects larger than 100 km, their physical state through variability measurements (solid body vs. a rubble pile), as well as their surface chemistry through color measurements. A proposed deep TNO survey, based on 1 hour exposures, may result in a sample of about 100,000 TNOs, while spending only 10% of the LSST observing time. Such a deep TNO survey would be capable of discovering Sedna-like objects at distances beyond 150 AU, thereby increasing the observable Solar System volume by about a factor of 7. The increase in data volume associated with LSST asteroid science will present many computational challenges to how we might extract tracks and orbits of asteroids from the underlying clutter. Tree-based algorithms for multihypothesis testing of asteroid tracks can help solve these challenges by providing the necessary 1000-fold speed-ups over current approaches while recovering 95% of the underlying asteroid populations.

Designing interfaces of hydrogenase-nanomaterial hybrids for efficient solar conversion.

PubMed

King, Paul W

2013-01-01

The direct conversion of sunlight into biofuels is an intriguing alternative to a continued reliance on fossil fuels. Natural photosynthesis has long been investigated both as a potential solution, and as a model for utilizing solar energy to drive a water-to-fuel cycle. The molecules and organizational structure provide a template to inspire the design of efficient molecular systems for photocatalysis. A clear design strategy is the coordination of molecular interactions that match kinetic rates and energetic levels to control the direction and flow of energy from light harvesting to catalysis. Energy transduction and electron-transfer reactions occur through interfaces formed between complexes of donor-acceptor molecules. Although the structures of several of the key biological complexes have been solved, detailed descriptions of many electron-transfer complexes are lacking, which presents a challenge to designing and engineering biomolecular systems for solar conversion. Alternatively, it is possible to couple the catalytic power of biological enzymes to light harvesting by semiconductor nanomaterials. In these molecules, surface chemistry and structure can be designed using ligands. The passivation effect of the ligand can also dramatically affect the photophysical properties of the semiconductor, and energetics of external charge-transfer. The length, degree of bond saturation (aromaticity), and solvent exposed functional groups of ligands can be manipulated to further tune the interface to control molecular assembly, and complex stability in photocatalytic hybrids. The results of this research show how ligand selection is critical to designing molecular interfaces that promote efficient self-assembly, charge-transfer and photocatalysis. This article is part of a Special Issue entitled: Metals in Bioenergetics and Biomimetics Systems. Copyright © 2013 Elsevier B.V. All rights reserved.

FFT analysis of sensible-heat solar-dynamic receivers

NASA Astrophysics Data System (ADS)

Lund, Kurt O.

The use of solar dynamic receivers with sensible energy storage in single-phase materials is considered. The feasibility of single-phase designs with weight and thermal performance comparable to existing two-phase designs is addressed. Linearized heat transfer equations are formulated for the receiver heat storage, representing the periodic input solar flux as the sum of steady and oscillating distributions. The steady component is solved analytically to produce the desired receiver steady outlet gas temperature, and the FFT algorithm is applied to the oscillating components to obtain the amplitudes and mode shapes of the oscillating solid and gas temperatures. The results indicate that sensible-heat receiver designs with performance comparable to state-of-the-art two-phase receivers are available.

Future space transport

NASA Technical Reports Server (NTRS)

Grishin, S. D.; Chekalin, S. V.

1984-01-01

Prospects for the mastery of space and the basic problems which must be solved in developing systems for both manned and cargo spacecraft are examined. The achievements and flaws of rocket boosters are discussed as well as the use of reusable spacecraft. The need for orbiting satellite solar power plants and related astrionics for active control of large space structures for space stations and colonies in an age of space industrialization is demonstrated. Various forms of spacecraft propulsion are described including liquid propellant rocket engines, nuclear reactors, thermonuclear rocket engines, electrorocket engines, electromagnetic engines, magnetic gas dynamic generators, electromagnetic mass accelerators (rail guns), laser rocket engines, pulse nuclear rocket engines, ramjet thermonuclear rocket engines, and photon rockets. The possibilities of interstellar flight are assessed.

A global low order spectral model designed for climate sensitivity studies

NASA Technical Reports Server (NTRS)

Hanna, A. F.; Stevens, D. E.

1984-01-01

A two level, global, spectral model using pressure as a vertical coordinate is developed. The system of equations describing the model is nonlinear and quasi-geostrophic. A moisture budget is calculated in the lower layer only with moist convective adjustment between the two layers. The mechanical forcing of topography is introduced as a lower boundary vertical velocity. Solar forcing is specified assuming a daily mean zenith angle. On land and sea ice surfaces a steady state thermal energy equation is solved to calculate the surface temperature. Over the oceans the sea surface temperatures are prescribed from the climatological average of January. The model is integrated to simulate the January climate.

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

Marion, Bill; Smith, Benjamin

Using performance data from some of the millions of installed photovoltaic (PV) modules with micro-inverters may afford the opportunity to provide ground-based solar resource data critical for developing PV projects. The method used back-solves for the direct normal irradiance (DNI) and the diffuse horizontal irradiance (DHI) from the micro-inverter ac production data. When the derived values of DNI and DHI were then used to model the performance of other PV systems, the annual mean bias deviations were within +/- 4%, and only 1% greater than when the PV performance was modeled using high quality irradiance measurements. An uncertainty analysis showsmore » the method better suited for modeling PV performance than using satellite-based global horizontal irradiance.« less

Correcting GOES-R Magnetometer Data for Stray Fields

NASA Technical Reports Server (NTRS)

Carter, Delano R.; Freesland, Douglas C.; Tadikonda, Sivakumara K.; Kronenwetter, Jeffrey; Todirita, Monica; Dahya, Melissa; Chu, Donald

2016-01-01

Time-varying spacecraft magnetic fields or stray fields are a problem for magnetometer systems. While constant fields can be removed with zero offset calibration, stray fields are difficult to distinguish from ambient field variations. Putting two magnetometers on a long boom and solving for both the ambient and stray fields can be a good idea, but this gradiometer solution is even more susceptible to noise than a single magnetometer. Unless the stray fields are larger than the magnetometer noise, simply averaging the two measurements is a more accurate approach. If averaging is used, it may be worthwhile to explicitly estimate and remove stray fields. Models and estimation algorithms are provided for solar array, arcjet and reaction wheel fields.

The LEO Archipelago: A system of earth-rings for communications, mass-transport to space, solar power, and control of global warming

NASA Astrophysics Data System (ADS)

Meulenberg, Andrew; Karthik Balaji, P. S.

2011-06-01

Man's quest to get into space is hindered by major problems (e.g., system-development and capital costs, expense of putting mass into orbit, trapped-radiation belts, and environmental impact of a large increase in rocket launches). A multi-purpose low-earth-orbit system of rings circling the earth - the "LEO ARCHIPELAGO TM" - is proposed as a means of solving or bypassing many of them. A fiber-optic ring about the earth would be an initial testing and developmental stage for the Ring Systems, while providing cash-flow through a LEO-based, high-band-width, world-wide communication system. A low-earth-orbit-based space-elevator system, "Sling-on-a-Ring TM", is proposed as the crucial developmental stage of the LEO Archipelago. Being a LEO-based heavy-mass lifter, rather than earth- or GEO-based, it is much less massive and therefore less costly than other proposed space-elevators. With the advent of lower-cost, higher-mass transport to orbit, the options for further space development (e.g., space solar power, radiation, and space-debris dampers, sun shades, and permanent LEO habitation) are greatly expanded. This paper provides an update of the Sling-on-a-Ring concept in terms of new materials, potential applications, and trade-offs associated with an earlier model. The impact of Colossal Carbon Tubes, CCT, a new material with high tensile strength, extremely-low density, and other favorable properties, and other new technologies (e.g., solar-powered lasers, power beaming to near-space and earth, and thermal-control systems) on the development of associated LEO-Ring systems is also explored. The material's effect on the timeline for the system development indicates the feasibility of near-term implementation of the system (possibly within the decade). The Sling-on-a-Ring can provide a less-expensive, environment-friendly mode of access to space. This would pave the way (via eventual operation at >1000 t per day by 2050) for large scale development of space-based technologies.

Solar Probe Plus: A NASA Mission to Touch the Sun

NASA Astrophysics Data System (ADS)

Fox, N. J.; Bale, S. D.; Decker, R. B.; Howard, R.; Kasper, J. C.; McComas, D. J.; Szabo, A.; Velli, M. M.

2013-12-01

Solar Probe Plus (SPP), currently in Phase B, will be the first mission to fly into the low solar corona, revealing how the corona is heated and the solar wind is accelerated, solving two fundamental mysteries that have been top priority science goals since such a mission was first proposed in 1958. The scale and concept of such a mission has been revised at intervals since that time, yet the core has always been a close encounter with the Sun. The primary science goal of the Solar Probe Plus mission is to determine the structure and dynamics of the Sun's coronal magnetic field, understand how the solar corona and wind are heated and accelerated, and determine what mechanisms accelerate and transport energetic particles. The SPP mission will achieve this by identifying and quantifying the basic plasma physical processes at the heart of the Heliosphere. SPP uses an innovative mission design, significant technology development and a risk-reducing engineering development to meet the SPP science objectives: 1) Trace the flow of energy that heats and accelerates the solar corona and solar wind; 2) Determine the structure and dynamics of the plasma and magnetic fields at the sources of the solar wind; and 3) Explore mechanisms that accelerate and transport energetic particles. In this poster, we present Solar Probe Plus and examine how the mission will address the science questions that have remained unanswered for over 5 decades.

Materials-Related Aspects of Thermochemical Water and Carbon Dioxide Splitting: A Review

PubMed Central

Roeb, Martin; Neises, Martina; Monnerie, Nathalie; Call, Friedemann; Simon, Heike; Sattler, Christian; Schmücker, Martin; Pitz-Paal, Robert

2012-01-01

Thermochemical multistep water- and CO2-splitting processes are promising options to face future energy problems. Particularly, the possible incorporation of solar power makes these processes sustainable and environmentally attractive since only water, CO2 and solar power are used; the concentrated solar energy is converted into storable and transportable fuels. One of the major barriers to technological success is the identification of suitable active materials like catalysts and redox materials exhibiting satisfactory durability, reactivity and efficiencies. Moreover, materials play an important role in the construction of key components and for the implementation in commercial solar plants. The most promising thermochemical water- and CO2-splitting processes are being described and discussed with respect to further development and future potential. The main materials-related challenges of those processes are being analyzed. Technical approaches and development progress in terms of solving them are addressed and assessed in this review.

Newtonian CAFE: a new ideal MHD code to study the solar atmosphere

NASA Astrophysics Data System (ADS)

González, J. J.; Guzmán, F.

2015-12-01

In this work we present a new independent code designed to solve the equations of classical ideal magnetohydrodynamics (MHD) in three dimensions, submitted to a constant gravitational field. The purpose of the code centers on the analysis of solar phenomena within the photosphere-corona region. In special the code is capable to simulate the propagation of impulsively generated linear and non-linear MHD waves in the non-isothermal solar atmosphere. We present 1D and 2D standard tests to demonstrate the quality of the numerical results obtained with our code. As 3D tests we present the propagation of MHD-gravity waves and vortices in the solar atmosphere. The code is based on high-resolution shock-capturing methods, uses the HLLE flux formula combined with Minmod, MC and WENO5 reconstructors. The divergence free magnetic field constraint is controlled using the Flux Constrained Transport method.

Newtonian CAFE: a new ideal MHD code to study the solar atmosphere

NASA Astrophysics Data System (ADS)

González-Avilés, J. J.; Cruz-Osorio, A.; Lora-Clavijo, F. D.; Guzmán, F. S.

2015-12-01

We present a new code designed to solve the equations of classical ideal magnetohydrodynamics (MHD) in three dimensions, submitted to a constant gravitational field. The purpose of the code centres on the analysis of solar phenomena within the photosphere-corona region. We present 1D and 2D standard tests to demonstrate the quality of the numerical results obtained with our code. As solar tests we present the transverse oscillations of Alfvénic pulses in coronal loops using a 2.5D model, and as 3D tests we present the propagation of impulsively generated MHD-gravity waves and vortices in the solar atmosphere. The code is based on high-resolution shock-capturing methods, uses the Harten-Lax-van Leer-Einfeldt (HLLE) flux formula combined with Minmod, MC, and WENO5 reconstructors. The divergence free magnetic field constraint is controlled using the Flux Constrained Transport method.

Technical Assistance | NREL

Science.gov Websites

Multi-Wind Heat Smart Grid Project. Advancing Energy Solutions in Alaska NREL provides analysis mission to transfer knowledge and innovation to solve the nation's energy challenges. The goal of this transportation energy efficiency and reduce transportation energy costs State Technical Assistance-solar market

On the Dynamical Foundations of the Lidov-Kozai Theory

NASA Astrophysics Data System (ADS)

Prokhorenko, V. I.

2018-01-01

The Lidov-Kozai theory developed by each of the authors independently in 1961-1962 is based on qualitative methods of studying the evolution of orbits for the satellite version of the restricted three-body problem (Hill's problem). At present, this theory is in demand in various fields of science: in the field of planetary research within the Solar system, the field of exoplanetary systems, and the field of high-energy physics in interstellar and intergalactic space. This has prompted me to popularize the ideas that underlie the Lidov-Kozai theory based on the experience of using this theory as an efficient tool for solving various problems related to the study of the secular evolution of the orbits of artificial planetary satellites under the influence of external gravitational perturbations with allowance made for the perturbations due to the polar planetary oblateness.

Mean-field theory of differential rotation in density stratified turbulent convection

NASA Astrophysics Data System (ADS)

Rogachevskii, I.

2018-04-01

A mean-field theory of differential rotation in a density stratified turbulent convection has been developed. This theory is based on the combined effects of the turbulent heat flux and anisotropy of turbulent convection on the Reynolds stress. A coupled system of dynamical budget equations consisting in the equations for the Reynolds stress, the entropy fluctuations and the turbulent heat flux has been solved. To close the system of these equations, the spectral approach, which is valid for large Reynolds and Péclet numbers, has been applied. The adopted model of the background turbulent convection takes into account an increase of the turbulence anisotropy and a decrease of the turbulent correlation time with the rotation rate. This theory yields the radial profile of the differential rotation which is in agreement with that for the solar differential rotation.

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

Shen, Yichen, E-mail: ycshen@mit.edu; Joannopoulos, John D.; Soljačić, Marin

Humankind has long endeavored to control the propagation direction of light. Since time immemorial, shades, lenses, and mirrors have been used to control the flow of light. In modern society, with the rapid development of nanotechnology, the control of light is moving toward devices at micrometer and even nanometer scales. At such scales, traditional devices based on geometrical optics reach their fundamental diffraction limits and cease to work. Nano-photonics, on the other hand, has attracted wide attention from researchers, especially in the last decade, due to its ability to manipulate light at the nanoscale. This review focuses on the nano-photonicsmore » systems that aim to select light based on its propagation direction. In the first half of this review, we survey the literature and the current state of the art focused on enabling optical broadband angular selectivity. The mechanisms we review can be classified into three main categories: (i) microscale geometrical optics, (ii) multilayer birefringent materials, and (iii) Brewster modes in plasmonic systems, photonic crystals, and metamaterials. In the second half, we present two categories of potential applications for broadband angularly selective systems. The first category aims at enhancing the efficiency of solar energy harvesting, through photovoltaic process or solar thermal process. The second category aims at enhancing light extracting efficiency and detection sensitivity. Finally, we discuss the most prominent challenges in broadband angular selectivity and some prospects on how to solve these challenges.« less

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

Deciphering The Fall And Rise Of The Dead Sea In Relation To Solar Forcing

NASA Astrophysics Data System (ADS)

Yousef, Shahinaz M.

2005-03-01

Solar Forcing on closed seas and Lakes is space time dependent. The Cipher of the Dead Sea level variation since 1200 BC is solved in the context of millenium and Wolf-Gleissberg solar cycles time scales. It is found that the pattern of Dead Sea level variation follows the pattern of major millenium solar cycles. The 70 m rise of Dead Sea around 1AD is due to the forcing of the maximum millenium major solar cycle. Although the pattern of the Dead Sea level variation is almost identical to major solar cycles pattern between 1100 and 1980 AD, there is a dating problem of the Dead Sea time series around 1100-1300 AD that time. A discrepancy that should be corrected for the solar and Dead Sea series to fit. Detailed level variations of the Dead Sea level for the past 200 years are solved in terms of the 80-120 years solar Wolf-Gliessberg magnetic cycles. Solar induced climate changes do happen at the turning points of those cycles. Those end-start and maximum turning points are coincident with the change in the solar rotation rate due to the presence of weak solar cycles. Such weak cycles occur in series of few cycles between the end and start of those Wolf-Gleissberg cycles. Another one or two weak r solar cycle occur following the maximum of those Wolf-Gleissberg cycles. Weak cycles induce drop in the energy budget emitted from the sun and reaching the Earth thus causing solar induced climate change. An 8 meter sudden rise of Dead Sea occur prior 1900 AD due to positive solar forcing of the second cycle of the weak cycles series on the Dead Sea. The same second weak cycle induced negative solar forcing on Lake Chad. The first weak solar cycle forced Lake Victoria to rise abruptly in 1878. The maximum turning point of the solar Wolf-Gleissberg cycle induced negative forcing on both the Aral Sea and the Dead Sea causing their shrinkage to an alarming reduced area ever since. On the other hand, few years delayed positive forcing caused Lake Chad and the Equatorial African lakes to rise abruptly by several meters. Since the present solar cycle number 23 is the first weak cycle of a series, and since it caused 1.6 m sharp rise in Lake Victoria in 1997, then there is a high probability that the Dead Sea will rise by the beginning of the second weak cycle in few years time. And since both the Aral Sea and the Dead Sea are very much in coherence since the late 1950s, then it is rather likely that the Aral Sea will rise with God's wish in the near future. However it is also demanded that Israel should allow more water of the Jordan River to feed the Dead Sea before its real death. Plans for joining the Dead sea to the Red and or to the Mediterranean Seas should be cancelled owing the damaging harm it will cause the Dead Sea as a perfect indicator of solar induced climate change on one hand. On the other hand, the Dead Sea time series always show abrupt changes that can be as high as 70 m; if we add to this a planned artificial rise of the Dead Sea to its level of the thirties, then a damaging flooding effect will ruin the establishments and environment greatly.

Annual DOE active solar heating and cooling contractors' review meeting. Premeeting proceedings and project summaries

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

None,

1981-09-01

Ninety-three project summaries are presented which discuss the following aspects of active solar heating and cooling: Rankine solar cooling systems; absorption solar cooling systems; desiccant solar cooling systems; solar heat pump systems; solar hot water systems; special projects (such as the National Solar Data Network, hybrid solar thermal/photovoltaic applications, and heat transfer and water migration in soils); administrative/management support; and solar collector, storage, controls, analysis, and materials technology. (LEW)

Penetrative convection

NASA Technical Reports Server (NTRS)

Moore, D. R.

1981-01-01

The current state of understanding of the most directly observable solar convection, the granulation and supergranulation is summarized. The body of work in which the complete time dependent Navier-Stokes equations and entropy transport equation are solved for a fully compressible atmosphere is considered. Relevant anelastic and incompressible calculations in two dimensions are also discussed.

Solar Spots - Activities to Introduce Solar Energy into the K-8 Curricula.

ERIC Educational Resources Information Center

Longe, Karen M.; McClelland, Michael J.

Following an introduction to solar technology which reviews solar heating and cooling, passive solar systems (direct gain systems, thermal storage walls, sun spaces, roof ponds, and convection loops), active solar systems, solar electricity (photovoltaic and solar thermal conversion systems), wind energy, and biomass, activities to introduce solar…

A transparently scalable visualization architecture for exploring the universe.

PubMed

Fu, Chi-Wing; Hanson, Andrew J

2007-01-01

Modern astronomical instruments produce enormous amounts of three-dimensional data describing the physical Universe. The currently available data sets range from the solar system to nearby stars and portions of the Milky Way Galaxy, including the interstellar medium and some extrasolar planets, and extend out to include galaxies billions of light years away. Because of its gigantic scale and the fact that it is dominated by empty space, modeling and rendering the Universe is very different from modeling and rendering ordinary three-dimensional virtual worlds at human scales. Our purpose is to introduce a comprehensive approach to an architecture solving this visualization problem that encompasses the entire Universe while seeking to be as scale-neutral as possible. One key element is the representation of model-rendering procedures using power scaled coordinates (PSC), along with various PSC-based techniques that we have devised to generalize and optimize the conventional graphics framework to the scale domains of astronomical visualization. Employing this architecture, we have developed an assortment of scale-independent modeling and rendering methods for a large variety of astronomical models, and have demonstrated scale-insensitive interactive visualizations of the physical Universe covering scales ranging from human scale to the Earth, to the solar system, to the Milky Way Galaxy, and to the entire observable Universe.

Planar rigid-flexible coupling spacecraft modeling and control considering solar array deployment and joint clearance

NASA Astrophysics Data System (ADS)

Li, Yuanyuan; Wang, Zilu; Wang, Cong; Huang, Wenhu

2018-01-01

Based on Nodal Coordinate Formulation (NCF) and Absolute Nodal Coordinate Formulation (ANCF), this paper establishes rigid-flexible coupling dynamic model of the spacecraft with large deployable solar arrays and multiple clearance joints to analyze and control the satellite attitude under deployment disturbance. Considering torque spring, close cable loop (CCL) configuration and latch mechanisms, a typical spacecraft composed of a rigid main-body described by NCF and two flexible panels described by ANCF is used as a demonstration case. Nonlinear contact force model and modified Coulomb friction model are selected to establish normal contact force and tangential friction model, respectively. Generalized elastic force are derived and all generalized forces are defined in the NCF-ANCF frame. The Newmark-β method is used to solve system equations of motion. The availability and superiority of the proposed model is verified through comparing with numerical co-simulations of Patran and ADAMS software. The numerical results reveal the effects of panel flexibility, joint clearance and their coupling on satellite attitude. The effects of clearance number, clearance size and clearance stiffness on satellite attitude are investigated. Furthermore, a proportional-differential (PD) attitude controller of spacecraft is designed to discuss the effect of attitude control on the dynamic responses of the whole system.

Neutrino oscillation studies with reactors

PubMed Central

Vogel, P.; Wen, L.J.; Zhang, C.

2015-01-01

Nuclear reactors are one of the most intense, pure, controllable, cost-effective and well-understood sources of neutrinos. Reactors have played a major role in the study of neutrino oscillations, a phenomenon that indicates that neutrinos have mass and that neutrino flavours are quantum mechanical mixtures. Over the past several decades, reactors were used in the discovery of neutrinos, were crucial in solving the solar neutrino puzzle, and allowed the determination of the smallest mixing angle θ13. In the near future, reactors will help to determine the neutrino mass hierarchy and to solve the puzzling issue of sterile neutrinos. PMID:25913819

Aerosol Optical Depth Measurements by Airborne Sun Photometer in SOLVE II: Comparisons to SAGE III, POAM III and Airborne Spectrometer Measurements

NASA Technical Reports Server (NTRS)

Russell, P.; Livingston, J.; Schmid, B.; Eilers, J.; Kolyer, R.; Redemann, J.; Ramirez, S.; Yee, J-H.; Swartz, W.; Shetter, R.

2004-01-01

The 14-channel NASA Ames Airborne Tracking Sunphotometer (AATS-14) measured solar-beam transmission on the NASA DC-8 during the Second SAGE III Ozone Loss and Validation Experiment (SOLVE II). This paper presents AATS-14 results for multiwavelength aerosol optical depth (AOD), including its spatial structure and comparisons to results from two satellite sensors and another DC-8 instrument. These are the Stratospheric Aerosol and Gas Experiment III (SAGE III), the Polar Ozone and Aerosol Measurement III (POAM III) and the Direct beam Irradiance Airborne Spectrometer (DIAS).

Neutrino oscillation studies with reactors

DOE PAGES

Vogel, P.; Wen, L.J.; Zhang, C.

2015-04-27

Nuclear reactors are one of the most intense, pure, controllable, cost-effective and well-understood sources of neutrinos. Reactors have played a major role in the study of neutrino oscillations, a phenomenon that indicates that neutrinos have mass and that neutrino flavours are quantum mechanical mixtures. Over the past several decades, reactors were used in the discovery of neutrinos, were crucial in solving the solar neutrino puzzle, and allowed the determination of the smallest mixing angle θ 13. In the near future, reactors will help to determine the neutrino mass hierarchy and to solve the puzzling issue of sterile neutrinos.

Neutrino oscillation studies with reactors.

PubMed

Vogel, P; Wen, L J; Zhang, C

2015-04-27

Nuclear reactors are one of the most intense, pure, controllable, cost-effective and well-understood sources of neutrinos. Reactors have played a major role in the study of neutrino oscillations, a phenomenon that indicates that neutrinos have mass and that neutrino flavours are quantum mechanical mixtures. Over the past several decades, reactors were used in the discovery of neutrinos, were crucial in solving the solar neutrino puzzle, and allowed the determination of the smallest mixing angle θ13. In the near future, reactors will help to determine the neutrino mass hierarchy and to solve the puzzling issue of sterile neutrinos.

Creation of closed life support systems

NASA Astrophysics Data System (ADS)

Gitelson, I.

The 40-year-long experience in devising ecological systems with a significantly closed material cycling (CES), which are intended for human life support outside the Earth's biosphere, allows us to state that this problem has been largely solved technically. To test the terrestrial prototypes of these systems: Bios in Krasnoyarsk, the Terrestrial Ecological System (TES) in Moscow, and Bioplex in Houston, crews of humans stayed inside them over long periods of time. In Bios-3 humans could be fully (100%) provided with regenerated air and water and with a vegetable part (80%) of their diet. One human requires 4.5 kW of light energy, which is equal to the light energy incident on an 8-m2 surface perpendicular to solar rays in the Earth's orbit. The regeneration of air and water can be alternatively performed by a 17-L2 microalgal cultivator with a light-receiving surface of 8 m at 2 kW of light energy or by a conveyer culture of agricultural plants. To regenerate the vegetable part of2 the diet to the full, the area must increase to 31.5 m per person. Similar values have been obtained in the TES and in Bioplex. It can be concluded that the system is ready to be implemented in the engineering-technical designs of specific versions: for orbital flights, for missions to Mars and other planets, and for stations on the Moon and Mars. To improve the CES further, a number of new key problems should be resolved. The first of them are: to robotize the technological processes and to establish an optimized system of the internal control of the CES by the crew working in it; to develop a hybrid physicochemical-biological technology for returning the dead-end products of biosynthesis into the system's cycling; to solve the fundamental problem of regenerating the human ration completely inside the CES by the autotrophic chemo - and photosynthesis. Once this problem is solved, the energy requirements for life support in space will be significantly reduced. This will also considerably contribute to the solution of the most pressing terrestrial problem - energy efficient production of food.

A study on characterization of stratospheric aerosol and gas parameters with the spacecraft solar occultation experiment

NASA Technical Reports Server (NTRS)

Chu, W. P.

1977-01-01

Spacecraft remote sensing of stratospheric aerosol and ozone vertical profiles using the solar occultation experiment has been analyzed. A computer algorithm has been developed in which a two step inversion of the simulated data can be performed. The radiometric data are first inverted into a vertical extinction profile using a linear inversion algorithm. Then the multiwavelength extinction profiles are solved with a nonlinear least square algorithm to produce aerosol and ozone vertical profiles. Examples of inversion results are shown illustrating the resolution and noise sensitivity of the inversion algorithms.

The Future of Geomagnetic Storm Predictions: Implications from Recent Solar and Interplanetary Observations

NASA Technical Reports Server (NTRS)

Tsurutani, B. T.; Gonzalez, W. D.

1995-01-01

Within the last 7-8 years, there has been a substantial growth in out knowledge of the solar and interplanetary causes of geomagnetic storms at Earth. This review article will not attempt to cover all of the work done during this period. This can be found elsewhere. Our emphasis here will be on recent efforts that expose important, presently unanswered questions that must be addressed and solved before true predictability of storms can be possible. Hopefully, this article will encourage some readers to join this effort and perhaps make major contributions to the field.

Explosive magnetic reconnection - Puzzle to be solved as the energy supply process for magnetospheric substorms?

NASA Technical Reports Server (NTRS)

Akasofu, S.-I.

1985-01-01

It is pointed out that magnetospheric substorms are perhaps the most basic type of disturbances which occur throughout the magnetosphere. There is little doubt that the energy for magnetospheric substorms is delivered from the sun to the magnetosphere by the solar wind, and theoretical and observational studies have been conducted to uncover the processes associated with the energy transfer from the solar wind to the magnetosphere, and the subsequent processes leading to various magnetospheric substorm phenomena. It has been widely accepted that explosive magnetic reconnection supplies the energy for magnetospheric substorm processes. It is indicated that the auroral phenomena must be various manifestations of a large-scale electrical discharge process which is powered by the solar wind-magnetosphere dynamo. Certain problems regarding explosive magnetic reconnection are discussed.

An Illumination- and Temperature-Dependent Analytical Model for Copper Indium Gallium Diselenide (CIGS) Solar Cells

DOE PAGES

Sun, Xingshu; Silverman, Timothy; Garris, Rebekah; ...

2016-07-18

In this study, we present a physics-based analytical model for copper indium gallium diselenide (CIGS) solar cells that describes the illumination- and temperature-dependent current-voltage (I-V) characteristics and accounts for the statistical shunt variation of each cell. The model is derived by solving the drift-diffusion transport equation so that its parameters are physical and, therefore, can be obtained from independent characterization experiments. The model is validated against CIGS I-V characteristics as a function of temperature and illumination intensity. This physics-based model can be integrated into a large-scale simulation framework to optimize the performance of solar modules, as well as predict themore » long-term output yields of photovoltaic farms under different environmental conditions.« less

Modern Solar Mysteries

NASA Technical Reports Server (NTRS)

Hathaway, David H.

2004-01-01

100 years ago we thought that the Sun and stars shone as a result of slow gravitational contraction over a few tens of millions of years - putting astronomers at odds with geologists who claimed that the Earth was much, much older. That mystery was solved in the 1920s and 30s with the discovery of nuclear energy (proving that the geologists had it right all along). Other scientific mysteries concerning the Sun have come and gone but three major mysteries remain: 1) How does the Sun produce sunspots with an 11-year cycle? 2) What produces the huge explosions that result in solar flares, prominence eruptions, and coronal mass ejections? and 3) Why is the Sun's outer atmosphere, the corona, so darned hot? Recent progress in solar astronomy reveals a single key to understanding all three of these mysteries.

Turbulent Transport in a Three-dimensional Solar Wind

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

Shiota, D.; Zank, G. P.; Adhikari, L.

2017-03-01

Turbulence in the solar wind can play essential roles in the heating of coronal and solar wind plasma and the acceleration of the solar wind and energetic particles. Turbulence sources are not well understood and thought to be partly enhanced by interaction with the large-scale inhomogeneity of the solar wind and the interplanetary magnetic field and/or transported from the solar corona. To investigate the interaction with background inhomogeneity and the turbulence sources, we have developed a new 3D MHD model that includes the transport and dissipation of turbulence using the theoretical model of Zank et al. We solve for themore » temporal and spatial evolution of three moments or variables, the energy in the forward and backward fluctuating modes and the residual energy and their three corresponding correlation lengths. The transport model is coupled to our 3D model of the inhomogeneous solar wind. We present results of the coupled solar wind-turbulence model assuming a simple tilted dipole magnetic configuration that mimics solar minimum conditions, together with several comparative intermediate cases. By considering eight possible solar wind and turbulence source configurations, we show that the large-scale solar wind and IMF inhomogeneity and the strength of the turbulence sources significantly affect the distribution of turbulence in the heliosphere within 6 au. We compare the predicted turbulence distribution results from a complete solar minimum model with in situ measurements made by the Helios and Ulysses spacecraft, finding that the synthetic profiles of the turbulence intensities show reasonable agreement with observations.« less

Solar Probe Plus: A NASA Mission to Touch the Sun

NASA Astrophysics Data System (ADS)

Fox, N. J.; Velli, M. M. C.; Kasper, J. C.; McComas, D. J.; Howard, R.; Bale, S. D.; Decker, R. B.

2014-12-01

Solar Probe Plus (SPP), currently in Phase C, will be the first mission to fly into the low solar corona, revealing how the corona is heated and the solar wind and energetic particles are accelerated, solving fundamental mysteries that have been top priority science goals since such a mission was first proposed in 1958. The scale and concept of such a mission has been revised at intervals since that time, yet the core has always been a close encounter with the Sun. The primary science goal of the Solar Probe Plus mission is to determine the structure and dynamics of the Sun's coronal magnetic field, understand how the solar corona and wind are heated and accelerated, and determine what mechanisms accelerate and transport energetic particles. The SPP mission will achieve this by identifying and quantifying the basic plasma physical processes at the heart of the Heliosphere. SPP uses an innovative mission design, significant technology development and a risk-reducing engineering development to meet the SPP science objectives: 1) Trace the flow of energy that heats and accelerates the solar corona and solar wind; 2) Determine the structure and dynamics of the plasma and magnetic fields at the sources of the solar wind; and 3) Explore mechanisms that accelerate and transport energetic particles. In this presentation, we present Solar Probe Plus and examine how the mission will address the science questions that have remained unanswered for over 5 decades.

Production of sunspots and their effects on the corona and solar wind: Insights from a new 3D flux-transport dynamo model

NASA Astrophysics Data System (ADS)

Kumar, Rohit; Jouve, Laurène; Pinto, Rui F.; Rouillard, Alexis P.

2018-01-01

We present a three-dimensional numerical model for the generation and evolution of the magnetic field in the solar convection zone, in which sunspots are produced and contribute to the cyclic reversal of the large-scale magnetic field. We then assess the impact of this dynamo-generated field on the structure of the solar corona and solar wind. This model solves the induction equation in which the velocity field is prescribed. This velocity field is a combination of a solar-like differential rotation and meridional circulation. We develop an algorithm that enables the magnetic flux produced in the interior to be buoyantly transported towards the surface to produce bipolar spots. We find that those tilted bipolar magnetic regions contain a sufficient amount of flux to periodically reverse the polar magnetic field and sustain dynamo action. We then track the evolution of these magnetic features at the surface during a few consecutive magnetic cycles and analyze their effects on the topology of the corona and on properties of the solar wind (distribution of streamers and coronal holes, and of slow and fast wind streams) in connection with current observations of the Sun.

Sterilization of instruments in solar ovens.

PubMed

Jørgensen, A F; Nøhr, K; Boisen, F; Nøhr, J

2002-01-01

The sterilization of instruments in rural health clinics in less developed countries is an increasing problem as chemical methods can no longer be recommended and fuel wood is becoming increasingly scarce. It seems obvious, therefore, to utilize solar energy for sterilization purposes. A solar oven was designed and manufactured using local materials and simple tools. It was tested by physical, chemical and microbiological methods and, after successful testing, installed in a rural clinic. The oven was able to generate temperatures above 180 degrees C. On days with direct sunlight the oven fulfilled the international recommendations for hot air sterilization. The chemical indicators, Browne's tubes type 3 and 5, also changed colour. It was difficult to reach the right value for the sterilization effect during months with a low sun position. A moveable oven, or two ovens, must be installed to solve this problem. The solar oven has proven to be a realistic method for the sterilization of instruments. The solar oven is easy to make and use. It saves fuel and can be used in most tropical areas.

Doping of polycrystalline CdTe for high-efficiency solar cells on flexible metal foil.

PubMed

Kranz, Lukas; Gretener, Christina; Perrenoud, Julian; Schmitt, Rafael; Pianezzi, Fabian; La Mattina, Fabio; Blösch, Patrick; Cheah, Erik; Chirilă, Adrian; Fella, Carolin M; Hagendorfer, Harald; Jäger, Timo; Nishiwaki, Shiro; Uhl, Alexander R; Buecheler, Stephan; Tiwari, Ayodhya N

2013-01-01

Roll-to-roll manufacturing of CdTe solar cells on flexible metal foil substrates is one of the most attractive options for low-cost photovoltaic module production. However, various efforts to grow CdTe solar cells on metal foil have resulted in low efficiencies. This is caused by the fact that the conventional device structure must be inverted, which imposes severe restrictions on device processing and consequently limits the electronic quality of the CdTe layer. Here we introduce an innovative concept for the controlled doping of the CdTe layer in the inverted device structure by means of evaporation of sub-monolayer amounts of Cu and subsequent annealing, which enables breakthrough efficiencies up to 13.6%. For the first time, CdTe solar cells on metal foil exceed the 10% efficiency threshold for industrialization. The controlled doping of CdTe with Cu leads to increased hole density, enhanced carrier lifetime and improved carrier collection in the solar cell. Our results offer new research directions for solving persistent challenges of CdTe photovoltaics.

Optimization methods and silicon solar cell numerical models

NASA Technical Reports Server (NTRS)

Girardini, K.; Jacobsen, S. E.

1986-01-01

An optimization algorithm for use with numerical silicon solar cell models was developed. By coupling an optimization algorithm with a solar cell model, it is possible to simultaneously vary design variables such as impurity concentrations, front junction depth, back junction depth, and cell thickness to maximize the predicted cell efficiency. An optimization algorithm was developed and interfaced with the Solar Cell Analysis Program in 1 Dimension (SCAP1D). SCAP1D uses finite difference methods to solve the differential equations which, along with several relations from the physics of semiconductors, describe mathematically the performance of a solar cell. A major obstacle is that the numerical methods used in SCAP1D require a significant amount of computer time, and during an optimization the model is called iteratively until the design variables converge to the values associated with the maximum efficiency. This problem was alleviated by designing an optimization code specifically for use with numerically intensive simulations, to reduce the number of times the efficiency has to be calculated to achieve convergence to the optimal solution.

Nonlinear data assimilation: towards a prediction of the solar cycle

NASA Astrophysics Data System (ADS)

Svedin, Andreas

The solar cycle is the cyclic variation of solar activity, with a span of 9-14 years. The prediction of the solar cycle is an important and unsolved problem with implications for communications, aviation and other aspects of our high-tech society. Our interest is model-based prediction, and we present a self-consistent procedure for parameter estimation and model state estimation, even when only one of several model variables can be observed. Data assimilation is the art of comparing, combining and transferring observed data into a mathematical model or computer simulation. We use the 3DVAR methodology, based on the notion of least squares, to present an implementation of a traditional data assimilation. Using the Shadowing Filter — a recently developed method for nonlinear data assimilation — we outline a path towards model based prediction of the solar cycle. To achieve this end we solve a number of methodological challenges related to unobserved variables. We also provide a new framework for interpretation that can guide future predictions of the Sun and other astrophysical objects.

Doping of polycrystalline CdTe for high-efficiency solar cells on flexible metal foil

NASA Astrophysics Data System (ADS)

Kranz, Lukas; Gretener, Christina; Perrenoud, Julian; Schmitt, Rafael; Pianezzi, Fabian; La Mattina, Fabio; Blösch, Patrick; Cheah, Erik; Chirilă, Adrian; Fella, Carolin M.; Hagendorfer, Harald; Jäger, Timo; Nishiwaki, Shiro; Uhl, Alexander R.; Buecheler, Stephan; Tiwari, Ayodhya N.

2013-08-01

Roll-to-roll manufacturing of CdTe solar cells on flexible metal foil substrates is one of the most attractive options for low-cost photovoltaic module production. However, various efforts to grow CdTe solar cells on metal foil have resulted in low efficiencies. This is caused by the fact that the conventional device structure must be inverted, which imposes severe restrictions on device processing and consequently limits the electronic quality of the CdTe layer. Here we introduce an innovative concept for the controlled doping of the CdTe layer in the inverted device structure by means of evaporation of sub-monolayer amounts of Cu and subsequent annealing, which enables breakthrough efficiencies up to 13.6%. For the first time, CdTe solar cells on metal foil exceed the 10% efficiency threshold for industrialization. The controlled doping of CdTe with Cu leads to increased hole density, enhanced carrier lifetime and improved carrier collection in the solar cell. Our results offer new research directions for solving persistent challenges of CdTe photovoltaics.

A substantial amount of hidden magnetic energy in the quiet Sun.

PubMed

Bueno, J Trujillo; Shchukina, N; Ramos, A Asensio

2004-07-15

Deciphering and understanding the small-scale magnetic activity of the quiet solar photosphere should help to solve many of the key problems of solar and stellar physics, such as the magnetic coupling to the outer atmosphere and the coronal heating. At present, we can see only approximately 1 per cent of the complex magnetism of the quiet Sun, which highlights the need to develop a reliable way to investigate the remaining 99 per cent. Here we report three-dimensional radiative transfer modelling of scattering polarization in atomic and molecular lines that indicates the presence of hidden, mixed-polarity fields on subresolution scales. Combining this modelling with recent observational data, we find a ubiquitous tangled magnetic field with an average strength of approximately 130 G, which is much stronger in the intergranular regions of solar surface convection than in the granular regions. So the average magnetic energy density in the quiet solar photosphere is at least two orders of magnitude greater than that derived from simplistic one-dimensional investigations, and sufficient to balance radiative energy losses from the solar chromosphere.

Present status of solid state photoelectrochemical solar cells and dye sensitized solar cells using PEO-based polymer electrolytes

NASA Astrophysics Data System (ADS)

Singh, Pramod Kumar; Nagarale, R. K.; Pandey, S. P.; Rhee, H. W.; Bhattacharya, Bhaskar

2011-06-01

Due to energy crises in the future, much effort is being directed towards alternate sources. Solar energy is accepted as a novel substitute for conventional sources of energy. Out of the long list of various types of solar cells available on the market, solid state photoelectrochemical solar cells (SSPECs) and dye sensitized solar cells (DSSCs) are proposed as an alternative to costly crystalline solar cell. This review provides a common platform for SSPECs and DSSCs using polymer electrolyte, particularly on polyethylene oxide (PEO)-based polymer electrolytes. Due to numerous advantageous properties of PEO, it is frequently used as an electrolyte in both SSPECs as well as DSSCs. In DSSCs, so far high efficiency (more than 11%) has been obtained only by using volatile liquid electrolyte, which suffers many disadvantages, such as corrosion, leakage and evaporation. The PEO-based solid polymer proves its importance and could be used to solve the problems stated above. The recent developments in SSPECs and DSSCs using modified PEO electrolytes by adding nano size inorganic fillers, blending with low molecular weight polymers and ionic liquid (IL) are discussed in detail. The role of ionic liquid in modifying the electrical, structural and photoelectrochemical properties of PEO polymer electrolytes is also described.

Backward-gazing method for heliostats shape errors measurement and calibration

NASA Astrophysics Data System (ADS)

Coquand, Mathieu; Caliot, Cyril; Hénault, François

2017-06-01

The pointing and canting accuracies and the surface shape of the heliostats have a great influence on the solar tower power plant efficiency. At the industrial scale, one of the issues to solve is the time and the efforts devoted to adjust the different mirrors of the faceted heliostats, which could take several months if the current methods were used. Accurate control of heliostat tracking requires complicated and onerous devices. Thus, methods used to adjust quickly the whole field of a plant are essential for the rise of solar tower technology with a huge number of heliostats. Wavefront detection is widely use in adaptive optics and shape error reconstruction. Such systems can be sources of inspiration for the measurement of solar facets misalignment and tracking errors. We propose a new method of heliostat characterization inspired by adaptive optics devices. This method aims at observing the brightness distributions on heliostat's surface, from different points of view close to the receiver of the power plant, in order to calculate the wavefront of the reflection of the sun on the concentrated surface to determine its errors. The originality of this new method is to use the profile of the sun to determine the defects of the mirrors. In addition, this method would be easy to set-up and could be implemented without sophisticated apparatus: only four cameras would be used to perform the acquisitions.

A peaking-regulation-balance-based method for wind & PV power integrated accommodation

NASA Astrophysics Data System (ADS)

Zhang, Jinfang; Li, Nan; Liu, Jun

2018-02-01

Rapid development of China’s new energy in current and future should be focused on cooperation of wind and PV power. Based on the analysis of system peaking balance, combined with the statistical features of wind and PV power output characteristics, a method of comprehensive integrated accommodation analysis of wind and PV power is put forward. By the electric power balance during night peaking load period in typical day, wind power installed capacity is determined firstly; then PV power installed capacity could be figured out by midday peak load hours, which effectively solves the problem of uncertainty when traditional method hard determines the combination of the wind and solar power simultaneously. The simulation results have validated the effectiveness of the proposed method.

Constraining inverse-curvature gravity with supernovae.

PubMed

Mena, Olga; Santiago, José; Weller, Jochen

2006-02-03

We show that models of generalized modified gravity, with inverse powers of the curvature, can explain the current accelerated expansion of the Universe without resorting to dark energy and without conflicting with solar system experiments. We have solved the Friedmann equations for the full dynamical range of the evolution of the Universe and performed a detailed analysis of supernovae data in the context of such models that results in an excellent fit. If we further include constraints on the current expansion of the Universe and on its age, we obtain that the matter content of the Universe is 0.07

Rings in astronomy and cosmology, 1600-1900

NASA Astrophysics Data System (ADS)

van Helden, A.

It was not until the 1640s that Descartes proposed a cosmology in which the universe is filled with vortices of invisible matter, and Huygens (1659) subsequently solved the problem posed by Saturn's telescopic appearances by postulating that the planet is surrounded by a ring. As Cartesian vortices fell out of favor in the mid-1700s, Kant and Lambert suggested cosmologies in which the galaxies were enormous disks of rotating matter. Over most of the 19th century, Laplace's nebular hypothesis was held to be supported by the increasing number of asteroids as well as the particle nature of Saturn's rings. More recently, rings of dispersed matter have played a prominent role in theories of the origin of the solar system.

Flight project data book, 1991

NASA Technical Reports Server (NTRS)

1991-01-01

The Office of Space Science and Applications (OSSA) is responsible for planning, directing, executing, and evaluating that part of the overall NASA program that has as its goal the use of the unique characteristics of the space environment to conduct a scientific study of the universe, to solve practical problems on Earth, and to provide the scientific research foundation for expanding human presence beyond Earth into the solar system. OSSA manages the development of NASA's flight instrumentation for space science and applications including free flying spacecraft, Shuttle and Space Station payloads, and the suborbital sounding rockets, balloons, and aircraft programs. A summary is provided of future flight missions, including those approved and currently under development and those which appear in the OSSA strategic plan.

Solar Probe Plus: A mission to touch the sun

NASA Astrophysics Data System (ADS)

Kinnison, J.; Lockwood, M. K.; Fox, N.; Conde, R.; Driesman, A.

Solar Probe Plus (SPP), currently in Phase B, will be the first mission to fly into the low solar corona, revealing how the corona is heated and the solar wind is accelerated, solving two fundamental mysteries that have been top priority science goals since such a mission was first proposed in 1958. The scale and concept of such a mission has been revised at intervals since that time, yet the core has always been a close encounter with the Sun. SPP uses an innovative mission design, significant technology development and a risk-reducing engineering development to meet the SPP science objectives: 1) determine the structure and dynamics of the magnetic fields at the sources of the fast and slow solar wind, 2) trace the flow of energy that heats the corona and accelerates the solar wind. and 3) determine what mechanisms accelerate and transport energetic particles. In this paper, we present the Solar Probe Plus mission along with a brief comparison with some previous concepts for such a mission, and discuss the trade studies that led to the SPP implementation. We present a summary of the challenges associated with operation in the solar encounter environment and discuss the technology development and engineering trade studies to compose a mission that will not only survive this environment, but will provide the data needed to answer the science questions that have remained unanswered to date.

Can the measurement of the cross-section of proton-capture on beryllium-7 be improved

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

Bowers, C.

1993-01-01

The solar neutrino problem'' arises from the discrepancy between the observations of solar neutrinos fluxes in experiments at Homestake and Kamiokande and the solar model predictions of those fluxes. Both experiments, which are sensitive mainly to high-energy neutrinos, observe fewer neutrinos than predicted by solar models. Most of the expected high-energy solar neutrinos come from the beta-decay of [sup 8]B, which is produced in the reaction [sup 7]Be(p,[gamma])[sup 8]B. A study of all of the measurements to date of the zero-energy S-factor for the reaction [sup 7]Be(p,[gamma])[sup 8]B concludes that S[sub 17](0) = 0.0224 +[plus minus] 0.0021 keV-barn. Although amore » 10% error in S[sub 17](0) alone wig not solve the solar neutrino problem, it would still be useful to nail down all of the inputs of the solar models as well as possible. This serves to guard against the possibility that a conspiracy among the errors might be the source of the discrepancy and provides tighter constraints on the new physics'' interpretations of the experimentally measured solar neutrino spectrum. In this paper, we examine several ways of improving this measurement. None appear to offer a significant improvement over past experiments.« less

Can the measurement of the cross-section of proton-capture on beryllium-7 be improved?

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

Bowers, C.

1993-01-01

The solar neutrino ``problem`` arises from the discrepancy between the observations of solar neutrinos fluxes in experiments at Homestake and Kamiokande and the solar model predictions of those fluxes. Both experiments, which are sensitive mainly to high-energy neutrinos, observe fewer neutrinos than predicted by solar models. Most of the expected high-energy solar neutrinos come from the beta-decay of {sup 8}B, which is produced in the reaction {sup 7}Be(p,{gamma}){sup 8}B. A study of all of the measurements to date of the zero-energy S-factor for the reaction {sup 7}Be(p,{gamma}){sup 8}B concludes that S{sub 17}(0) = 0.0224 +{plus_minus} 0.0021 keV-barn. Although a 10%more » error in S{sub 17}(0) alone wig not solve the solar neutrino problem, it would still be useful to nail down all of the inputs of the solar models as well as possible. This serves to guard against the possibility that a conspiracy among the errors might be the source of the discrepancy and provides tighter constraints on the ``new physics`` interpretations of the experimentally measured solar neutrino spectrum. In this paper, we examine several ways of improving this measurement. None appear to offer a significant improvement over past experiments.« less

Remote sensing of snow and ice

NASA Technical Reports Server (NTRS)

Rango, A.

1979-01-01

This paper reviews remote sensing of snow and ice, techniques for improved monitoring, and incorporation of the new data into forecasting and management systems. The snowcover interpretation of visible and infrared data from satellites, automated digital methods, radiative transfer modeling to calculate the solar reflectance of snow, and models using snowcover input data and elevation zones for calculating snowmelt are discussed. The use of visible and near infrared techniques for inferring snow properties, microwave monitoring of snowpack characteristics, use of Landsat images for collecting glacier data, monitoring of river ice with visible imagery from NOAA satellites, use of sequential imagery for tracking ice flow movement, and microwave studies of sea ice are described. Applications of snow and ice research to commercial use are examined, and it is concluded that a major problem to be solved is characterization of snow and ice in nature, since assigning of the correct properties to a real system to be modeled has been difficult.

Differential correction capability of the GTDS using TDRSS data

NASA Technical Reports Server (NTRS)

Liu, S. Y.; Soskey, D. G.; Jacintho, J.

1980-01-01

A differential correction (DC) capability was implemented in the Goddard Trajectory Determination System (GTDS) to process satellite tracking data acquired via the Tracking and Data Relay Satellite System (TRDRSS). Configuration of the TDRSS is reviewed, observation modeling is presented, and major features of the capability are discussed. The following types of TDRSS data can be processed by GTDS: two way relay range and Doppler measurements, hybrid relay range and Doppler measurements, one way relay Doppler measurements, and differenced one way relay Doppler measurements. These data may be combined with conventional ground based direct tracking data. By using Bayesian weighted least squares techniques, the software allows the simultaneous determination of the trajectories of up to four different satellites - one user satellite and three relay satellites. In addition to satellite trajectories, the following parameters can be optionally solved: for drag coefficient, reflectivity of a satellite for solar radiation pressure, transponder delay, station position, and biases.

Reconfiguration of Smart Distribution Network in the Presence of Renewable DG’s Using GWO Algorithm

NASA Astrophysics Data System (ADS)

Siavash, M.; Pfeifer, C.; Rahiminejad, A.; Vahidi, B.

2017-08-01

In this paper, the optimal reconfiguration of smart distribution system is performed with the aim of active power loss reduction and voltage stability improvement. The distribution network is considered equipped with wind turbines and solar cells as Renewable DG’s (RDG’s). Because of the presence of smart metering devices, the network state is known accurately at any moment. Based on the network conditions (the amount of load and generation of RDG’s), the optimal configuration of the network is obtained. The optimization problem is solved using a recently introduced method known as Grey Wolf Optimizer (GWO). The proposed approach is applied on 69-bus radial test system and the results of the GWO are compared to those of Particle Swarm Optimization (PSO), and Genetic Algorithm (GA). The results show the effectiveness of the proposed approach and the selected optimization method.

2016 Year in Review Video- NASA’s Marshall Space Flight Center

NASA Image and Video Library

2016-12-22

The work underway today at NASA’s Marshall Space Flight Center is making it possible to send humans beyond Earth’s orbit and into deep space on bold new missions of space exploration. Marshall teams are designing and building NASA’s Space Launch System, the most powerful rocket ever built and the only launch vehicle capable of launching human explorers to Mars. Using the International Space Station’s orbiting lab, Marshall flight controllers provided round-the-clock oversight of science experiments, supporting the first-ever DNA sequencing in space, pioneering 3-D printing capabilities and advancing human health research. Several successful New Frontiers deep-space robotic missions including OSIRIS-REx, New Horizons and Juno, made new discoveries and refined theories of the solar system. And Marshall collaborations with outside partners are yielding innovative technologies and solving technical challenges that are making the Journey to Mars a reality.

An engineering analysis of a closed cycle plant growth module

NASA Technical Reports Server (NTRS)

Stickford, G. H., Jr.; Jakob, F. E.; Landstrom, D. K.

1986-01-01

The SOLGEM model is a numerical engineering model which solves the flow and energy balance equations for the air flowing through a growing environment, assuming quasi-steady state conditions within the system. SOLGEM provides a dynamic simulation of the controlled environment system in that the temperature and flow conditions of the growing environment are estimated on an hourly basis in response to the weather data and the plant growth parameters. The flow energy balance considers the incident solar flux; incoming air temperature, humidity, and flow rate; heat exchange with the roof and floor; and heat and moisture exchange with the plants. A plant transpiration subroutine was developed based plant growth research facility, intended for the study of bioregenerative life support theories. The results of a performance analysis of the plant growth module are given. The estimated energy requirements of the module components and the total energy are given.

Remote sensing of the solar photosphere: a tale of two methods

NASA Astrophysics Data System (ADS)

Viavattene, G.; Berrilli, F.; Collados Vera, M.; Del Moro, D.; Giovannelli, L.; Ruiz Cobo, B.; Zuccarello, F.

2018-01-01

Solar spectro-polarimetry is a powerful tool to investigate the physical processes occurring in the solar atmosphere. The different states of polarization and wavelengths have in fact encoded the information about the thermodynamic state of the solar plasma and the interacting magnetic field. In particular, the radiative transfer theory allows us to invert the spectro-polarimetric data to obtain the physical parameters of the different atmospheric layers and, in particular, of the photosphere. In this work, we present a comparison between two methods used to analyze spectro-polarimetric data: the classical Center of Gravity method in the weak field approximation and an inversion code that solves numerically the radiative transfer equation. The Center of Gravity method returns reliable values for the magnetic field and for the line-of-sight velocity in those regions where the weak field approximation is valid (field strength below 400 G), while the inversion code is able to return the stratification of many physical parameters in the layers where the spectral line used for the inversion is formed.

Vertically Aligned Graphene Sheets Membrane for Highly Efficient Solar Thermal Generation of Clean Water.

PubMed

Zhang, Panpan; Li, Jing; Lv, Lingxiao; Zhao, Yang; Qu, Liangti

2017-05-23

Efficient utilization of solar energy for clean water is an attractive, renewable, and environment friendly way to solve the long-standing water crisis. For this task, we prepared the long-range vertically aligned graphene sheets membrane (VA-GSM) as the highly efficient solar thermal converter for generation of clean water. The VA-GSM was prepared by the antifreeze-assisted freezing technique we developed, which possessed the run-through channels facilitating the water transport, high light absorption capacity for excellent photothermal transduction, and the extraordinary stability in rigorous conditions. As a result, VA-GSM has achieved average water evaporation rates of 1.62 and 6.25 kg m -2 h -1 under 1 and 4 sun illumination with a superb solar thermal conversion efficiency of up to 86.5% and 94.2%, respectively, better than that of most carbon materials reported previously, which can efficiently produce the clean water from seawater, common wastewater, and even concentrated acid and/or alkali solutions.

Study of relationships of material properties and high efficiency solar cell performance on material composition

NASA Technical Reports Server (NTRS)

Sah, C. T.

1983-01-01

The performance improvements obtainable from extending the traditionally thin back-surface-field (BSF) layer deep into the base of silicon solar cells under terrestrial solar illumination (AM1) are analyzed. This extended BSF cell is also known as the back-drift-field cell. About 100 silicon cells were analyzed, each with a different emitter or base dopant impurity distribution whose selection was based on physically anticipated improvements. The four principal performance parameters (the open-circuit voltage, the short-circuit current, the fill factor, and the maximum efficiency) are computed using a FORTRAN program, called Circuit Technique for Semiconductor-device Analysis, CTSA, which numerically solves the six Shockley Equations under AM1 solar illumination at 88.92 mW/cm, at an optimum cell thickness of 50 um. The results show that very significant performance improvements can be realized by extending the BSF layer thickness from 2 um (18% efficiency) to 40 um (20% efficiency).

Underwater wireless optical communication using a lens-free solar panel receiver

NASA Astrophysics Data System (ADS)

Kong, Meiwei; Sun, Bin; Sarwar, Rohail; Shen, Jiannan; Chen, Yifei; Qu, Fengzhong; Han, Jun; Chen, Jiawang; Qin, Huawei; Xu, Jing

2018-11-01

In this paper, we first propose that self-powered solar panels featuring large receiving area and lens-free operation have great application prospect in underwater vehicles or underwater wireless sensor networks (UWSNs) for data collection. It is envisioned to solve the problem of link alignment. The low-cost solar panel used in the experiment has a large receiving area of 5 cm2 and a receiving angle of 20°. Over a 1-m air channel, a 16-quadrature amplitude modulation (QAM) orthogonal frequency division multiplexing (OFDM) signal at a data rate of 20.02 Mb/s is successfully transmitted within the receiving angle of 20°. Over a 7-m tap water channel, we achieve data rates of 20.02 Mb/s using 16-QAM, 18.80 Mb/s using 32-QAM and 22.56 Mb/s using 64-QAM, respectively. By adding different quantities of Mg(OH)2 powders into the water, the impact of water turbidity on the solar panel-based underwater wireless optical communication (UWOC) is also investigated.

Possibility of using sources of vacuum ultraviolet irradiation to solve problems of space material science

NASA Technical Reports Server (NTRS)

Verkhoutseva, E. T.; Yaremenko, E. I.

1974-01-01

An urgent problem in space materials science is simulating the interaction of vacuum ultraviolet (VUV) of solar emission with solids in space conditions, that is, producing a light source with a distribution that approximates the distribution of solar energy. Information is presented on the distribution of the energy flux of VUV of solar radiation. Requirements that must be satisfied by the VUV source used for space materials science are formulated, and a critical evaluation is given of the possibilities of using existing sources for space materials science. From this evaluation it was established that none of the sources of VUV satisfies the specific requirements imposed on the simulator of solar radiation. A solution to the problem was found to be in the development of a new type of source based on exciting a supersonic gas jet flowing into vacuum with a sense electron beam. A description of this gas-jet source, along with its spectral and operation characteristics, is presented.

Self-Consistent and Time-Dependent Solar Wind Models

NASA Technical Reports Server (NTRS)

Ong, K. K.; Musielak, Z. E.; Rosner, R.; Suess, S. T.; Sulkanen, M. E.

1997-01-01

We describe the first results from a self-consistent study of Alfven waves for the time-dependent, single-fluid magnetohydrodynamic (MHD) solar wind equations, using a modified version of the ZEUS MHD code. The wind models we examine are radially symmetrical and magnetized; the initial outflow is described by the standard Parker wind solution. Our study focuses on the effects of Alfven waves on the outflow and is based on solving the full set of the ideal nonlinear MHD equations. In contrast to previous studies, no assumptions regarding wave linearity, wave damping, and wave-flow interaction are made; thus, the models naturally account for the back-reaction of the wind on the waves, as well as for the nonlinear interaction between different types of MHD waves. Our results clearly demonstrate when momentum deposition by Alfven waves in the solar wind can be sufficient to explain the origin of fast streams in solar coronal holes; we discuss the range of wave amplitudes required to obtained such fast stream solutions.

Lunar and Planetary Science XXXV: Special Session: Oxygen in the Solar System, I

NASA Technical Reports Server (NTRS)

2004-01-01

The Special Session: Oxygen in the Solar System, I, included the following reports:Oxygen in the Solar System: Origins of Isotopic and Redox Complexity; The Origin of Oxygen Isotope Variations in the Early Solar System; Solar and Solar-Wind Oxygen Isotopes and the Genesis Mission; Solar 18O/17O and the Setting for Solar Birth; Oxygen Isotopes in Early Solar System Materials: A Perspective Based on Microbeam Analyses of Chondrules from CV Carbonaceous Chondrites; Insight into Primordial Solar System Oxygen Reservoirs from Returned Cometary Samples; Tracing Meteorites to Their Sources Through Asteroid Spectroscopy; Redox Conditions Among the Terrestrial Planets; Redox Complexity in Martian Meteorites: Implications for Oxygen in the Terrestrial Planets; Implications of Sulfur Isotopes for the Evolution of Atmospheric Oxygen; Oxygen in the Outer Solar System; and On the Oxidation States of the Galilean Satellites: Implications for Internal Structures.

Solar energy

NASA Technical Reports Server (NTRS)

Rapp, D.

1981-01-01

The book opens with a review of the patterns of energy use and resources in the United States, and an exploration of the potential of solar energy to supply some of this energy in the future. This is followed by background material on solar geometry, solar intensities, flat plate collectors, and economics. Detailed attention is then given to a variety of solar units and systems, including domestic hot water systems, space heating systems, solar-assisted heat pumps, intermediate temperature collectors, space heating/cooling systems, concentrating collectors for high temperatures, storage systems, and solar total energy systems. Finally, rights to solar access are discussed.

Orbiting observatory SOHO finds source of high-speed "wind" blowing from the Sun

NASA Astrophysics Data System (ADS)

1999-02-01

"The search for the source of the solar wind has been like the hunt for the source of the Nile," said Dr. Don Hassler of the Southwest Research Institute, Boulder, Colorado, lead author of the paper in Science. "For 30 years, scientists have observed high-speed solar wind coming from regions in the solar atmosphere with open magnetic field lines, called coronal holes. However, only recently, with the observations from SOHO, have we been able to measure the detailed structure of this source region". The solar wind comes in two varieties : high-speed and low-speed. The low-speed solar wind moves at "only" 1.5 million kilometres per hour, while the high-speed wind is even faster, moving at speeds as high as 3 million kilometres per hour. As it flows past Earth, the solar wind changes the shape and structure of the Earth's magnetic field. In the past, the solar wind didn't affect us directly, but as we become increasingly dependent on advanced technology, we become more susceptible to its effects. Researchers are learning that variations in the solar wind flow can cause dramatic changes in the shape of the Earth's magnetic field, which can damage satellites and disrupt communications and electrical power systems. The nature and origin of the solar wind is one of the main mysteries ESA's solar observatory SOHO was designed to solve. It has long been thought that the solar wind flows from coronal holes; what is new is the discovery that these outflows are concentrated in specific patches at the edges of the honeycomb-shaped magnetic fields. Just below the surface of the Sun there are large convection cells, and each cell has a magnetic field associated with it. "If one thinks of these cells as paving stones in a patio, then the solar wind is breaking through like grass around the edges, concentrated in the corners where the paving stones meet", said Dr. Helen Mason, University of Cambridge, England, and co-author of the paper to appear in Science. "However, at speeds ranging from 30,000 km/h at the surface to over 3 million km/h, the solar wind "grows" much faster than grass". "Looking at the spot where the solar wind actually appears is extremely important", says co-author Dr. Philippe Lemaire of the Institut d'Astrophysique Spatiale in Orsay, France. The Solar Ultraviolet Measurements of Emitted Radiation (SUMER) spectrometer on SOHO detected the solar wind by observing the ultraviolet spectrum over a large area of the solar north polar region. The SUMER instrument was built under the leadership of Dr. Klaus Wilhelm at the Max-Planck-Institut für Aeronomie in Lindau, Germany, with key contributions from the Institut d'Astrophysique Spatiale in Orsay, France, the NASA Goddard Space Flight Center in Greenbelt, Maryland, and the University of California at Berkeley, with financial support from German, French, US and Swiss national agencies. "Identification of the detailed structure of the source region of the fast solar wind is an important step in solving the solar wind acceleration problem. We can now focus our attention on the plasma conditions and the dynamic processes seen in the corners of the magnetic field structures", says Dr. Wilhelm, also co-author of the Science paper. A spectrum results from the separation of light into its component colours, which correspond to different wavelengths. Blue light has a shorter wavelength and is more energetic than red. A spectrum is similar to what is seen when a prism separates white light into a rainbow of distinct colours. By analysing light this way, astronomers learn a great deal about the object emitting the light, such as its temperature, chemical composition, and motion. The ultraviolet light observed by SUMER is actually invisible to the human eye and cannot penetrate the Earth's atmosphere. The hot gas in the solar wind source region emits light at certain ultraviolet wavelengths. When the hot gas flows towards Earth, as it does in the solar wind, the wavelengths of the ultraviolet light emitted become shorter, a phenomenon called Doppler shift. This is similar to the way an ambulance siren appears to change tone as it speeds by. When the ambulance moves towards us, its sound is compressed to a shorter wavelength, resulting in a higher tone. As it moves away, its sound is stretched to a longer wavelength, resulting in a lower tone. Motion towards us, away from the solar surface, was detected as blueshifts and identified as the beginning of the solar wind. SOHO operates at a special vantage point 1.5 million kilometres out in space, on the sunward side of the Earth. The project is an international collaboration between ESA and NASA. SOHO was launched on an Atlas rocket from Cape Canaveral Air Station, Florida, in December 1995 and is operated from the Goddard Space Flight Center in Greenbelt, Maryland.

Drift-Alfven eigenmodes in inhomogeneous plasma

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

Vranjes, J.; Poedts, S.

2006-03-15

A set of three nonlinear equations describing drift-Alfven waves in a nonuniform magnetized plasma is derived and discussed both in linear and nonlinear limits. In the case of a cylindric radially bounded plasma with a Gaussian density distribution in the radial direction the linearized equations are solved exactly yielding general solutions for modes with quantized frequencies and with radially dependent amplitudes. The full set of nonlinear equations is also solved yielding particular solutions in the form of rotating radially limited structures. The results should be applicable to the description of electromagnetic perturbations in solar magnetic structures and in astrophysical column-likemore » objects including cosmic tornados.« less

Optimal heliocentric trajectories for solar sail with minimum area

NASA Astrophysics Data System (ADS)

Petukhov, Vyacheslav G.

2018-05-01

The fixed-time heliocentric trajectory optimization problem is considered for planar solar sail with minimum area. Necessary optimality conditions are derived, a numerical method for solving the problem is developed, and numerical examples of optimal trajectories to Mars, Venus and Mercury are presented. The dependences of the minimum area of the solar sail from the date of departure from the Earth, the time of flight and the departing hyperbolic excess of velocity are analyzed. In particular, for the rendezvous problem (approaching a target planet with zero relative velocity) with zero departing hyperbolic excess of velocity for a flight duration of 1200 days it was found that the minimum area-to-mass ratio should be about 12 m2/kg for trajectory to Venus, 23.5 m2/kg for the trajectory to Mercury and 25 m2/kg for trajectory to Mars.

Simulation studies on the standing and traveling wave thermoacoustic prime movers

NASA Astrophysics Data System (ADS)

Skaria, Mathew; Rasheed, K. K. Abdul; Shafi, K. A.; Kasthurirengan, S.; Behera, Upendra

2014-01-01

Thermoacoustic systems have been a focus of recent research due to its structural simplicity, high reliability due to absence of moving parts, and can be driven by low grade energy such as fuel, gas, solar energy, waste heat etc. There has been extensive research on both standing wave and traveling wave systems. Towards the development of such systems, simulations can be carried out by several methods such as (a) solving the energy equation, (b) enthalpy flow model, (c) DeltaEC, a free software available from LANL, USA (d) Computational Fluid Dynamics (CFD) etc. We present here the simulation studies of standing wave and traveling wave thermoacoustic prime movers using CFD and DeltaEC. The CFD analysis is carried out using Fluent 6.3.26, incorporating the necessary boundary conditions with different working fluids at different operating pressures. The results obtained by CFD are compared with those obtained using DeltaEC. Also, the CFD simulation of the thermoacoustically driven refrigerator is presented.

Simulation studies on the standing and traveling wave thermoacoustic prime movers

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

Skaria, Mathew; Rasheed, K. K. Abdul; Shafi, K. A.

Thermoacoustic systems have been a focus of recent research due to its structural simplicity, high reliability due to absence of moving parts, and can be driven by low grade energy such as fuel, gas, solar energy, waste heat etc. There has been extensive research on both standing wave and traveling wave systems. Towards the development of such systems, simulations can be carried out by several methods such as (a) solving the energy equation, (b) enthalpy flow model, (c) DeltaEC, a free software available from LANL, USA (d) Computational Fluid Dynamics (CFD) etc. We present here the simulation studies of standingmore » wave and traveling wave thermoacoustic prime movers using CFD and DeltaEC. The CFD analysis is carried out using Fluent 6.3.26, incorporating the necessary boundary conditions with different working fluids at different operating pressures. The results obtained by CFD are compared with those obtained using DeltaEC. Also, the CFD simulation of the thermoacoustically driven refrigerator is presented.« less

78 FR 63276 - Interim Policy, FAA Review of Solar Energy System Projects on Federally Obligated Airports

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-23

.... Background There is growing interest in installing solar photovoltaic (PV) and solar hot water (SHW) systems on airports. While solar PV or SHW systems (henceforth referred to as solar energy systems) are... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Interim Policy, FAA Review of Solar...

Thermal Assessment of a Latent-Heat Energy Storage Module During Melting and Freezing for Solar Energy Applications

NASA Astrophysics Data System (ADS)

Ramos Archibold, Antonio

Capital investment reduction, exergetic efficiency improvement and material compatibility issues have been identified as the primary techno-economic challenges associated, with the near-term development and deployment of thermal energy storage (TES) in commercial-scale concentrating solar power plants. Three TES techniques have gained attention in the solar energy research community as possible candidates to reduce the cost of solar-generated electricity, namely (1) sensible heat storage, (2) latent heat (tank filled with phase change materials (PCMs) or encapsulated PCMs packed in a vessel) and (3) thermochemical storage. Among these the PCM macro-encapsulation approach seems to be one of the most-promising methods because of its potential to develop more effective energy exchange, reduce the cost associated with the tank and increase the exergetic efficiency. However, the technological barriers to this approach arise from the encapsulation techniques used to create a durable capsule, as well as an assessment of the fundamental thermal energy transport mechanisms during the phase change. A comprehensive study of the energy exchange interactions and induced fluid flow during melting and solidification of a confined storage medium is reported in this investigation from a theoretical perspective. Emphasis has been placed on the thermal characterization of a single constituent storage module rather than an entire storage system, in order to, precisely capture the energy exchange contributions of all the fundamental heat transfer mechanisms during the phase change processes. Two-dimensional, axisymmetric, transient equations for mass, momentum and energy conservation have been solved numerically by the finite volume scheme. Initially, the interaction between conduction and natural convection energy transport modes, in the absence of thermal radiation, is investigated for solar power applications at temperatures (300--400°C). Later, participating thermal radiation within the storage medium has been included in order to extend the conventional natural convection-dominated model and to analyze its influence on the melting and freezing dynamics at elevated temperatures (800-850°C). A parametric analysis has been performed in order to ascertain the effects of the controlling parameters on the melting/freezing rates and the total and radiative heat transfer rates at the inner surface of the shell. The results show that the presence of thermal radiation enhances the melting and solidification processes. Finally, a simplified model of the packed bed heat exchanger with multiple spherical capsules filled with the storage medium and positioned in a vertical array inside a cylindrical container is analyzed and numerically solved. The influence of the inlet mass flow rate, inner shell surface emissivity and PCM attenuation coefficient on the melting dynamics of the PCM has been analyzed and quantified.

Designing, building, and testing a solar thermoelectric generation, STEG, for energy delivery to remote residential areas in developing regions

NASA Astrophysics Data System (ADS)

Moumouni, Yacouba

New alternatives and inventive renewable energy techniques which encompass both generation and power management solutions are fundamental for meeting remote residential energy supply and demand today, especially if the grid is quasi-inexistent. Solar thermoelectric generators can be a cost-effective alternative to photovoltaics for a remote residential household power supply. A complete solar thermoelectric energy harvesting system is presented for energy delivery to remote residential areas in developing regions. To this end, the entire system was built, modeled, and then validated with LTspice simulator software via thermal-to-electrical analogy schemes. Valuable data in conjunction with two novel LTspice circuits were obtained, showing the achievability of analyzing transient heat transfer with the Spice simulator. Hence, the proposed study begins with a comprehensive method of extracting thermal parameters that appear in thermoelectric modules. A step-by-step procedure was developed and followed to succinctly extract parameters, such as the Seebeck coefficient, electrical conductivity, thermal resistance, and thermal conductivity needed to model the system. Data extracted from datasheet, material properties, and geometries were successfully utilized to compute the thermal capacities and resistances necessary to perform the analogy. In addition, temperature variations of the intrinsic internal parameters were accounted for in this process for accuracy purposes. The steps that it takes to simulate any thermo-electrical system with the LTspice simulator are thoroughly explained in this work. As a consequence, an improved Spice model for a thermoelectric generator is proposed. Experimental results were compiled in the form of a lookup table and then fed into the Spice simulator using the piecewise linear (PWL) command in order to validate the model. Experimental results show that a temperature differential of 13.43°C was achievable whereas the simulation indicates a temperature gap of 9.86°C, with the higher error being associated with the hot side. Also, since the analytical method of transient heat transfer analysis is cumbersome, an LTspice model of a real-world solar thermoelectric generation system was investigated. All the physical parameters were converted into their electrical equivalences through the thermal-to-electrical analogy. Real site direct normal insolation was fed into the Spice model via PWL in order to capture the true system's thermal behavior. Interestingly, two distinct analogies result from this study: 1) an RC analogy and 2) another analogy similar to an N-type doped semiconductor material's carrier density dependence with temperature. The RC analogy is derived in order to demonstrate how thermoelectric generation systems respond to square wave-like solar radiation. This analogy is utilized to measure temperature variations on the cold side of the Spice model; it shows 80% accuracy. The N-type analogy is intended to help analyze the actual performance of a LTC3105 converter. However a few of the problems to be solved remain at the practical level. Despite the unusual operation of the thermoelectric modules with the solar radiation, the measurements and simulation were in good agreement, thus validating the new thermal modeling strategy.

An unmanned probe to Pluto

NASA Technical Reports Server (NTRS)

1990-01-01

Now that Voyager II has completed its grand tour of the solar system, all the planets in the solar system, with the exception of Pluto, have been studied. Even now, missions to return to Mercury, Venus, Mars Jupiter, and Saturn are currently flying or are planned. However, a mission to explore Pluto is not, at the present time, being considered seriously. The design problem presented to the students was very general, i.e., design an unmanned mission to Pluto with a launch window constraint of the years 2000 to 2010. All other characteristics of the mission, such as mission type (flyby, orbiter, lander, penetrator), scientific objectives and payload, and the propulsion system were to be determined by the design teams. The design studies exposed several general problems to be solved. Due to the extreme distance to Pluto (and a corresponding travel time in the range of 10 to 25 years), the spacecraft had to be lighter and more robust than current spacecraft designs. In addition, advanced propulsion concepts had to be considered. These included the new generation of launch vehicles and upper stages and nuclear electric propulsion. The probe design offered an abundance of synthesis and analysis problems. These included sizing trade studies, selection of subsystem components, analysis of spacecraft dynamics, stability and control, structural design and material selection, trajectory design, and selection of scientific equipment. Since the characteristics of the mission, excluding the launch window, were to be determined by the design teams, the solutions varied widely.

Solving the Meteorological Challenges of Creating a Sustainable Energy System (Invited)

NASA Astrophysics Data System (ADS)

Marquis, M.

2010-12-01

Global energy demand is projected to double from 13 TW at the start of this century to 28 TW by the middle of the century. This translates into obtaining 1000 MW (1 GW, the amount produced by an average nuclear or coal power plant) of new energy every single day for the next 40 years. The U.S. Department of Energy has conducted three feasibility studies in the last two years identifying the costs, challenges, impacts, and benefits of generating large portions of the nation’s electricity from wind and solar energy, in the new two decades. The 20% Wind by 2030 report found that the nation could meet one-fifth of its electricity demand from wind energy by 2030. The second report, the Eastern Wind Integration and Transmission Study, considered similar costs, challenges, and benefits, but considered 20% wind energy in the Eastern Interconnect only, with a target date of 2024. The third report, the Western Wind and Solar Integration Study, considered the operational impact of up to 35% penetration of wind, photovoltaics (PVs) and, concentrating solar power (CSP) on the power system operated by the WestConnect group, with a target date of 2017. All three studies concluded that it is technically feasible to obtain these high penetration levels of renewable energy, but that increases in the balancing area cooperation or coordination, increased utilization of transmission and building of transmission in some cases, and improved weather forecasts are needed. Current energy systems were designed for dispatchable fuels, such as coal, natural gas and nuclear energy. Fitting weather-driven renewable energy into today's energy system is like fitting a square peg into a round hole. If society chooses to meet a significant portion of new energy demand from weather-driven renewable energy, such as wind and solar energy, a number of obstacles must be overcome. Some of these obstacles are meteorological and climatological issues that are amenable to scientific research. For variable renewable energy sources to reach high penetration levels, electric system operators and utilities need better atmo¬spheric observations, models, and forecasts. Current numerical weather prediction models have not been optimized to help the nation use renewable energy. Improved meteorological observations (e.g., wind turbine hub-height wind speeds, surface direct and diffuse solar radiation), as well as observations through a deeper layer of the atmosphere for assimilation into NWP models, are needed. Particularly urgent is the need for improved forecasts of ramp events. Longer-term predictions of renewable resources, on the seasonal to decadal scale, are also needed. Improved understanding of the variability and co-variability of wind and solar energy, as well as their correlations with large-scale climate drivers, would assist decision-makers in long-term planning. This talk with discuss the feasibility and benefits of developing enhanced weather forecasts and climate information specific to the needs of a growing renewable energy infrastructure.

Potassium-chemical synthesis of 3D graphene from CO 2 and its excellent performance in HTM-free perovskite solar cells

DOE PAGES

Wei, Wei; Hu, Baoyun; Jin, Fangming; ...

2017-03-29

The conversion of greenhouse gas CO 2 into novel materials is the most promising approach to solve greenhouse gas issues. In this paper, we report for the first time the reaction of potassium with CO 2 to synthesize three-dimensional honeycomb-like structured graphene (3DHG). Furthermore, 3DHG exhibited excellent performance as a counter electrode for hole transport material (HTM)-free perovskite solar cells, leading to a power conversion efficiency of 10.06%. Finally, this work constitutes a new aspect of potassium chemistry for material synthesis from a greenhouse gas and the generation of electrical energy from sunlight.

Development of a liquid metal slip ring

NASA Technical Reports Server (NTRS)

Weinberger, S. M.

1972-01-01

A liquid metal slip ring/solar orientation mechanism was designed and a model tested. This was a follow-up of previous efforts for the development of a gallium liquid metal slip ring in which the major problem was the formation and ejection of debris. A number of slip ring design approaches were studied. The probe design concept was fully implemented with detail drawings and a model was successfully tested for dielectric strength, shock vibration, acceleration and operation. The conclusions are that a gallium liquid metal slip ring/solar orientation mechanism is feasible and that the problem of debris formation and ejection has been successfully solved.

Inversion of solar extinction data from the Apollo-Soyuz Test Project Stratospheric Aerosol Measurement (ASTP/SAM) experiment

NASA Technical Reports Server (NTRS)

Pepin, T. J.

1977-01-01

The inversion methods are reported that have been used to determine the vertical profile of the extinction coefficient due to the stratospheric aerosols from data measured during the ASTP/SAM solar occultation experiment. Inversion methods include the onion skin peel technique and methods of solving the Fredholm equation for the problem subject to smoothing constraints. The latter of these approaches involves a double inversion scheme. Comparisons are made between the inverted results from the SAM experiment and near simultaneous measurements made by lidar and balloon born dustsonde. The results are used to demonstrate the assumptions required to perform the inversions for aerosols.

Zero-field dichroism in the solar chromosphere.

PubMed

Sainz, R Manso; Bueno, J Trujillo

2003-09-12

We explain the linear polarization of the Ca ii infrared triplet observed close to the edge of the solar disk. In particular, we demonstrate that the physical origin of the enigmatic polarizations of the 866.2 and 854.2 nm lines lies in the existence of atomic polarization in their metastable (2)D(3)(/2, 5/2) lower levels, which produces differential absorption of polarization components (dichroism). To this end, we have solved the problem of the generation and transfer of polarized radiation by taking fully into account all the relevant optical pumping mechanisms in multilevel atomic models. We argue that "zero-field" dichroism may be of great diagnostic value in astrophysics.

Non-gravitational perturbations and satellite geodesy

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

Milani, A.; Nobill, A.M.; Farinella, P.

1987-01-01

This book presents the basic ideas of the physics of non-gravitational perturbations and the mathematics required to compute their orbital effects. It conveys the relevance of the different problems that must be solved to achieve a given level of accuracy in orbit determination and in recovery of geophysically significant parameters. Selected Contents are: Orders of Magnitude of the Perturbing Forces, Tides and Apparent Forces, Tools from Celestial Mechanics, Solar Radiation Pressure-Direct Effects: Satellite-Solar Radiation Interaction, Long-Term Effects on Semi-Major Axis, Radiation Pressure-Indirect Effects: Earth-Reflected Radiation Pressure, Anisotropic Thermal Emission, Drag: Orbital Perturbations by a Drag-Like Force, and Charged Particle Drag.

Transport of Solar Wind Fluctuations: A Two-Component Model

NASA Technical Reports Server (NTRS)

Oughton, S.; Matthaeus, W. H.; Smith, C. W.; Breech, B.; Isenberg, P. A.

2011-01-01

We present a new model for the transport of solar wind fluctuations which treats them as two interacting incompressible components: quasi-two-dimensional turbulence and a wave-like piece. Quantities solved for include the energy, cross helicity, and characteristic transverse length scale of each component, plus the proton temperature. The development of the model is outlined and numerical solutions are compared with spacecraft observations. Compared to previous single-component models, this new model incorporates a more physically realistic treatment of fluctuations induced by pickup ions and yields improved agreement with observed values of the correlation length, while maintaining good observational accord with the energy, cross helicity, and temperature.

Spectroscopy Made Easy: A New Tool for Fitting Observations with Synthetic Spectra

NASA Technical Reports Server (NTRS)

Valenti, J. A.; Piskunov, N.

1996-01-01

We describe a new software package that may be used to determine stellar and atomic parameters by matching observed spectra with synthetic spectra generated from parameterized atmospheres. A nonlinear least squares algorithm is used to solve for any subset of allowed parameters, which include atomic data (log gf and van der Waals damping constants), model atmosphere specifications (T(sub eff, log g), elemental abundances, and radial, turbulent, and rotational velocities. LTE synthesis software handles discontiguous spectral intervals and complex atomic blends. As a demonstration, we fit 26 Fe I lines in the NSO Solar Atlas (Kurucz et al.), determining various solar and atomic parameters.

Solar array technology evaluation program for SEPS (Solar Electrical Propulsion Stage)

NASA Technical Reports Server (NTRS)

1974-01-01

An evaluation of the technology and the development of a preliminary design for a 25 kilowatt solar array system for solar electric propulsion are discussed. The solar array has a power to weight ratio of 65 watts per kilogram. The solar array system is composed of two wings. Each wing consists of a solar array blanket, a blanket launch storage container, an extension/retraction mast assembly, a blanket tensioning system, an array electrical harness, and hardware for supporting the system for launch and in the operating position. The technology evaluation was performed to assess the applicable solar array state-of-the-art and to define supporting research necessary to achieve technology readiness for meeting the solar electric propulsion system solar array design requirements.

The solar energetic particle propagation of solar flare events on 24th solar cycle.

NASA Astrophysics Data System (ADS)

Paluk, P.; Khumlumlert, T.; Kanlayaprasit, N.; Aiemsa-ad, N.

2017-09-01

Now the Sun is in the 24th solar cycle. The peak of solar cycle correspond to the number of the Sun activities, which one of them is solar flare. The solar flare is the violent explosion at the solar atmosphere and releases the high energy ion from the Sun to the interplanetary medium. Solar energetic particles or solar cosmic ray have important effect on the Earth, such as disrupt radio communication. We analyze the particle transport of the solar flare events on August 9, 2011, January 27, 2012, and November 3, 2013 in 24th solar cycle. The particle data for each solar flare was obtained from SIS instrument on ACE spacecraft. We simulate the particle transport with the equation of Ruffolo 1995, 1998. We solve the transport equation with the numerical technique of finite different. We find the injection duration from the Sun to the Earth by the compared fitting method of piecewise linear function between the simulation results and particle data from spacecraft. The position of these solar flare events are on the west side of the Sun, which are N18W68, N33W85, and S12W16. We found that mean free path is roughly constant for a single event. This implies that the interplanetary scattering is approximately energy independent, but the level of scattering varies with time. The injection duration decreases with increasing energy. We found the resultant variation of the highest energy and lowest energy, because the effect of space environments and the number of the detected data was small. The high mean free path of the high energy particles showed the transport capability of particles along to the variable magnetic field line. The violent explosion of these solar flares didn’t affect on the Earth magnetic field with Kp-index less than 3.

A Report on the Science Summer Camp for the Gifted 9th Grade Students.

ERIC Educational Resources Information Center

Kyeonggi Province Board of Education, Suweon (Republic of Korea).

A summer science camp was held in Korea for 30 ninth grade students gifted in science. Students were divided into three groups (physics, chemistry, and biology) for activities which included problem solving, brainstorming, and experimental work. The experiments of the physics group addressed the use of solar energy, the chemistry group focused on…

Disruptive collisions as the origin of 67P/C-G and small bilobate comets

NASA Astrophysics Data System (ADS)

Michel, Patrick; Schwartz, Stephen R.; Jutzi, Martin; Marchi, Simone; Richardson, Derek C.; Zhang, Yun

2016-10-01

Images of comets sent by spacecraft have shown us that bilobate shapes seem to be common in the cometary population. This has been most recently evidenced by the images of comet 67P/C-G obtained by the ESA Rosetta mission, which show a low-density elongated body interpreted as a contact binary. The origin of such bilobate comets has been thought to be primordial because it requires the slow accretion of two bodies that become the two main components of the final object. However, slow accretion does not only occur during the primordial phase of the Solar System, but also later during the reaccumulation processes immediately following collisional disruptions of larger bodies. We perform numerical simulations of disruptions of large bodies. We demonstrate that during the ensuing gravitational phase, in which the generated fragments interact under their mutual gravity, aggregates with bi-lobed or elongated shapes formed form by reaccumulation at speeds that are at or below the range of those assumed in primordial accretion scenarios [1]. The same scenario has been demonstrated to occur in the asteroid belt to explain the origin of asteroid families [2] and has provided insight into the shapes of thus-far observed asteroids such as 25143 Itokawa [3]. Here we show that it is also a more general outcome that applies to disruption events in the outer Solar System. Moreover, we show that high temperature regions are very localized during the impact process, which solves the problem of the survival of organics and volatiles in the collisional process. The advantage of this scenario for the formation of small bilobate shapes, including 67P/C-G, is that it does not necessitate a primordial origin, as such disruptions can occur at later stages of the Solar System. This demonstrates how such comets can be relatively young, consistent with other studies that show that these shapes are unlikely to be formed early on and survive the entire history of the Solar System [4].[1] Schwartz, S.R. et al. 2016, in preparation; [2] Michel, P. et al. 2001, Science 294, 1696; [3] Michel, P., Richardson, D.C. 2013, A&A 554, L1; [4] Jutzi, M. et al. 2016 submitted to A&A.

24 CFR 200.950 - Building product standards and certification program for solar water heating system.

Code of Federal Regulations, 2011 CFR

2011-04-01

... certification program for solar water heating system. 200.950 Section 200.950 Housing and Urban Development... solar water heating system. (a) Applicable standards. (1) All solar water heating systems shall be...) Document OG-300-93, Operating Guidelines and Minimum Standards for Certifying Solar Water Heating Systems...

24 CFR 200.950 - Building product standards and certification program for solar water heating system.

Code of Federal Regulations, 2010 CFR

2010-04-01

... certification program for solar water heating system. 200.950 Section 200.950 Housing and Urban Development... solar water heating system. (a) Applicable standards. (1) All solar water heating systems shall be...) Document OG-300-93, Operating Guidelines and Minimum Standards for Certifying Solar Water Heating Systems...

The evolution of energetic particles and the emitted radiation in solar flares. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Lu, Edward Tsang

1989-01-01

The evolution of accelerated particle distributions in a magnetized plasma and the resulting radiation are calculated, and the results are applied to solar flares. To study the radiation on timescales of order the particle lifetimes, the evolution of the particle distribution is determined by the use of the Fokker-Planck equation including Coulomb collisions and magnetic mirroring. Analytic solution to the equations are obtained for limiting cases such as homogeneous injection in a homogeneous plasma, and for small pitch angle. These analytic solutions are then used to place constraints on flare parameters such as density, loop length, and the injection timescale for very short implusive solar flares. For general particle distributions in arbitrary magnetic field and background density, the equation is solved numerically. The relative timing of microwaves and X-rays during individual flares is investigated. A number of possible sources for excessive microwave flux are discussed including a flattening in the electron spectrum above hard X-ray energies, thermal synchrotron emission, and trapping of electron by converging magnetic fields. Over shorter timescales, the Fokker-Planck equation is solved numerically to calculate the temporal evolution of microwaves and X-rays from nonthermal thick target models. It is shown that magnetic trapping will not account for the observed correlation of microwaves of approximately 0.15 seconds behind X-rays in flares with rapid time variation, and thus higher energy electrons must be accelerated later than lower energy electrons.

Heliocentric phasing performance of electric sail spacecraft

NASA Astrophysics Data System (ADS)

Mengali, Giovanni; Quarta, Alessandro A.; Aliasi, Generoso

2016-10-01

We investigate the heliocentric in-orbit repositioning problem of a spacecraft propelled by an Electric Solar Wind Sail. Given an initial circular parking orbit, we look for the heliocentric trajectory that minimizes the time required for the spacecraft to change its azimuthal position, along the initial orbit, of a (prescribed) phasing angle. The in-orbit repositioning problem can be solved using either a drift ahead or a drift behind maneuver and, in general, the flight times for the two cases are different for a given value of the phasing angle. However, there exists a critical azimuthal position, whose value is numerically found, which univocally establishes whether a drift ahead or behind trajectory is superior in terms of flight time it requires for the maneuver to be completed. We solve the optimization problem using an indirect approach for different values of both the spacecraft maximum propulsive acceleration and the phasing angle, and the solution is then specialized to a repositioning problem along the Earth's heliocentric orbit. Finally, we use the simulation results to obtain a first order estimate of the minimum flight times for a scientific mission towards triangular Lagrangian points of the Sun-[Earth+Moon] system.

NEWTON - NEW portable multi-sensor scienTific instrument for non-invasive ON-site characterization of rock from planetary surface and sub-surfaces

NASA Astrophysics Data System (ADS)

Díaz-Michelena, M.; de Frutos, J.; Ordóñez, A. A.; Rivero, M. A.; Mesa, J. L.; González, L.; Lavín, C.; Aroca, C.; Sanz, M.; Maicas, M.; Prieto, J. L.; Cobos, P.; Pérez, M.; Kilian, R.; Baeza, O.; Langlais, B.; Thébault, E.; Grösser, J.; Pappusch, M.

2017-09-01

In space instrumentation, there is currently no instrument dedicated to susceptibly or complete magnetization measurements of rocks. Magnetic field instrument suites are generally vector (or scalar) magnetometers, which locally measure the magnetic field. When mounted on board rovers, the electromagnetic perturbations associated with motors and other elements make it difficult to reap the benefits from the inclusion of such instruments. However, magnetic characterization is essential to understand key aspects of the present and past history of planetary objects. The work presented here overcomes the limitations currently existing in space instrumentation by developing a new portable and compact multi-sensor instrument for ground breaking high-resolution magnetic characterization of planetary surfaces and sub-surfaces. This new technology introduces for the first time magnetic susceptometry (real and imaginary parts) as a complement to existing compact vector magnetometers for planetary exploration. This work aims to solve the limitations currently existing in space instrumentation by means of providing a new portable and compact multi-sensor instrument for use in space, science and planetary exploration to solve some of the open questions on the crustal and more generally planetary evolution within the Solar System.

High reduction of interfacial charge recombination in colloidal quantum dot solar cells by metal oxide surface passivation.

PubMed

Chang, Jin; Kuga, Yuki; Mora-Seró, Iván; Toyoda, Taro; Ogomi, Yuhei; Hayase, Shuzi; Bisquert, Juan; Shen, Qing

2015-03-12

Bulk heterojunction (BHJ) solar cells based on colloidal QDs and metal oxide nanowires (NWs) possess unique and outstanding advantages in enhancing light harvesting and charge collection in comparison to planar architectures. However, the high surface area of the NW structure often brings about a large amount of recombination (especially interfacial recombination) and limits the open-circuit voltage in BHJ solar cells. This problem is solved here by passivating the surface of the metal oxide component in PbS colloidal quantum dot solar cells (CQDSCs). By coating thin TiO2 layers onto ZnO-NW surfaces, the open-circuit voltage and power conversion efficiency have been improved by over 40% in PbS CQDSCs. Characterization by transient photovoltage decay and impedance spectroscopy indicated that the interfacial recombination was significantly reduced by the surface passivation strategy. An efficiency as high as 6.13% was achieved through the passivation approach and optimization for the length of the ZnO-NW arrays (device active area: 16 mm2). All solar cells were tested in air, and exhibited excellent air storage stability (without any performance decline over more than 130 days). This work highlights the significance of metal oxide passivation in achieving high performance BHJ solar cells. The charge recombination mechanism uncovered in this work could shed light on the further improvement of PbS CQDSCs and/or other types of solar cells.

Acoustic Gravity Waves in the Ionosphere and Thermosphere During the 2017 Solar Eclipse

NASA Astrophysics Data System (ADS)

Lin, C. Y. T.; Deng, Y.

2017-12-01

During the 2017 solar eclipse, as the sudden cavity of solar radiation created by the lunar shadow moves across the United States on August 21, 2017, decreases in local IT temperature and density are expected. The average velocity of the total solar eclipse across the United States is 700 m/s. The forefront and wake of the lunar shadow are expected to induce acoustic gravity waves according to previous studies of atmosphere waves induced by traveling wave packets moving at different velocities. Meanwhile, moving toward the cross-track direction of the obscuration footprint, weaker transitions will likely create mesoscale to large-scale traveling disturbances. We will use the Global Ionosphere Thermosphere Model, a global circulation model solving for non-hydrostatic equations, with high-resolution settings to investigate the IT responses related to the acoustic-gravity wave perturbations during the 2017 solar eclipse. The simulation will be performed with a sub-degree resolution in longitude and latitude for 3 hours when the atmosphere of the North America sector is mostly obscured. The observable differences between the eclipsed and non-eclipsed scenarios will be examined in detail and be interpreted as consequences from the solar eclipse. We will investigate the evolution of waves during the event and establish a theoretical baseline for further comparisons with observations.

Solar Thermo-coupled Electrochemical Oxidation of Aniline in Wastewater for the Complete Mineralization Beyond an Anodic Passivation Film.

PubMed

Yuan, Dandan; Tian, Lei; Li, Zhida; Jiang, Hong; Yan, Chao; Dong, Jing; Wu, Hongjun; Wang, Baohui

2018-02-15

Herein, we report the solar thermal electrochemical process (STEP) aniline oxidation in wastewater for totally solving the two key obstacles of the huge energy consumption and passivation film in the electrochemical treatment. The process, fully driven by solar energy without input of any other energies, sustainably serves as an efficient thermoelectrochemical oxidation of aniline by the control of the thermochemical and electrochemical coordination. The thermocoupled electrochemical oxidation of aniline achieved a fast rate and high efficiency for the full minimization of aniline to CO 2 with the stability of the electrode and without formation of polyaniline (PAN) passivation film. A clear mechanism of aniline oxidation indicated a switching of the reactive pathway by the STEP process. Due to the coupling of solar thermochemistry and electrochemistry, the electrochemical current remained stable, significantly improving the oxidation efficiency and mineralization rate by apparently decreasing the electrolytic potential when applied with high temperature. The oxidation rate of aniline and chemical oxygen demand (COD) removal rate could be lifted up to 2.03 and 2.47 times magnification compared to conventional electrolysis, respectively. We demonstrate that solar-driven STEP processes are capable of completely mineralizing aniline with high utilization of solar energy. STEP aniline oxidation can be utilized as a green, sustainable water treatment.

A probabilistic approach to radiative energy loss calculations for optically thick atmospheres - Hydrogen lines and continua

NASA Technical Reports Server (NTRS)

Canfield, R. C.; Ricchiazzi, P. J.

1980-01-01

An approximate probabilistic radiative transfer equation and the statistical equilibrium equations are simultaneously solved for a model hydrogen atom consisting of three bound levels and ionization continuum. The transfer equation for L-alpha, L-beta, H-alpha, and the Lyman continuum is explicitly solved assuming complete redistribution. The accuracy of this approach is tested by comparing source functions and radiative loss rates to values obtained with a method that solves the exact transfer equation. Two recent model solar-flare chromospheres are used for this test. It is shown that for the test atmospheres the probabilistic method gives values of the radiative loss rate that are characteristically good to a factor of 2. The advantage of this probabilistic approach is that it retains a description of the dominant physical processes of radiative transfer in the complete redistribution case, yet it achieves a major reduction in computational requirements.

Spherically symmetric vacuum in covariant F (T )=T +α/2 T2+O (Tγ) gravity theory

NASA Astrophysics Data System (ADS)

DeBenedictis, Andrew; Ilijić, Saša

2016-12-01

Recently, a fully covariant version of the theory of F (T ) torsion gravity has been introduced by M. Kršśák and E. Saridakis [Classical Quantum Gravity 33, 115009 (2016)]. In covariant F (T ) gravity, the Schwarzschild solution is not a vacuum solution for F (T )≠T , and therefore determining the spherically symmetric vacuum is an important open problem. Within the covariant framework, we perturbatively solve the spherically symmetric vacuum gravitational equations around the Schwarzschild solution for the scenario with F (T )=T +(α /2 )T2 , representing the dominant terms in theories governed by Lagrangians analytic in the torsion scalar. From this, we compute the perihelion shift correction to solar system planetary orbits as well as perturbative gravitational effects near neutron stars. This allows us to set an upper bound on the magnitude of the coupling constant, α , which governs deviations from general relativity. We find the bound on this nonlinear torsion coupling constant by specifically considering the uncertainty in the perihelion shift of Mercury. We also analyze a bound from a similar comparison with the periastron orbit of the binary pulsar PSR J0045-7319 as an independent check for consistency. Setting bounds on the dominant nonlinear coupling is important in determining if other effects in the Solar System or greater universe could be attributable to nonlinear torsion.

Prediction of stellar occultations by distant solar system bodies in the Gaia era

NASA Astrophysics Data System (ADS)

Desmars, Josselin; Camargo, Julio; Sicardy, Bruno; Braga-Ribas, Felipe; Vieira-Martins, Roberto; Assafin, Marcelo; Bérard, Diane; Benedetti-Rossi, Gustavo

2018-04-01

Stellar occultations are a unique technique to access physical characteristics of distant solar system objects from the ground. They allow the measure of the size and the shape at kilometric level, the detection of tenuous atmospheres (few nanobars), and the investigation of close vicinity (satellites, rings) of Transneptunian objects and Centaurs. This technique is made successful thanks to accurate predictions of occultations. Accuracy of the predictions depends on the uncertainty in the position of the occulted star and the object's orbit. The Gaia stellar catalogue (Gaia Collaboration (2017)) now allows to get accurate astrometric stellar positions (to the mas level). The main uncertainty remains on the orbit. In this context, we now take advantage of the NIMA method (Desmars et al.(2015)) for the orbit determination and of the Gaia DR1 catalogue for the astrometry. In this document, we show how the orbit determination is improved by reducing current and some past observations with Gaia DR1. Moreover, we also use more than 45 past positive occultations observed in the 2009-2017 period to derive very accurate astrometric positions only depending on the position of the occulted stars (about few mas with Gaia DR1). We use the case of (10199) Chariklo as an illustration. The main limitation lies in the imprecision of the proper motions which is going to be solved by the Gaia DR2 release.

Solar Power System Design for the Solar Probe+ Mission

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.; Schmitz, Paul C.; Kinnison, James; Fraeman, Martin; Roufberg, Lew; Vernon, Steve; Wirzburger, Melissa

2008-01-01

Solar Probe+ is an ambitious mission proposed to the solar corona, designed to make a perihelion approach of 9 solar radii from the surface of the sun. The high temperature, high solar flux environment makes this mission a significant challenge for power system design. This paper summarizes the power system conceptual design for the solar probe mission. Power supplies considered included nuclear, solar thermoelectric generation, solar dynamic generation using Stirling engines, and solar photovoltaic generation. The solar probe mission ranges from a starting distance from the sun of 1 AU, to a minimum distance of about 9.5 solar radii, or 0.044 AU, from the center of the sun. During the mission, the solar intensity ranges from one to about 510 times AM0. This requires power systems that can operate over nearly three orders of magnitude of incident intensity.

24 CFR 203.18a - Solar energy system.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 24 Housing and Urban Development 2 2013-04-01 2013-04-01 false Solar energy system. 203.18a... § 203.18a Solar energy system. (a) The dollar limitation provided in § 203.18(a) may be increased by up... to the installation of a solar energy system. (b) Solar energy system is defined as any addition...

24 CFR 203.18a - Solar energy system.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 24 Housing and Urban Development 2 2014-04-01 2014-04-01 false Solar energy system. 203.18a... § 203.18a Solar energy system. (a) The dollar limitation provided in § 203.18(a) may be increased by up... to the installation of a solar energy system. (b) Solar energy system is defined as any addition...

24 CFR 203.18a - Solar energy system.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 24 Housing and Urban Development 2 2012-04-01 2012-04-01 false Solar energy system. 203.18a... § 203.18a Solar energy system. (a) The dollar limitation provided in § 203.18(a) may be increased by up... to the installation of a solar energy system. (b) Solar energy system is defined as any addition...

24 CFR 203.18a - Solar energy system.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Solar energy system. 203.18a... § 203.18a Solar energy system. (a) The dollar limitation provided in § 203.18(a) may be increased by up... to the installation of a solar energy system. (b) Solar energy system is defined as any addition...

24 CFR 203.18a - Solar energy system.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 24 Housing and Urban Development 2 2011-04-01 2011-04-01 false Solar energy system. 203.18a... § 203.18a Solar energy system. (a) The dollar limitation provided in § 203.18(a) may be increased by up... to the installation of a solar energy system. (b) Solar energy system is defined as any addition...

Introduction to solar heating and cooling design and sizing

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

Not Available

This manual is designed to introduce the practical aspects of solar heating/cooling systems to HVAC contractors, architects, engineers, and other interested individuals. It is intended to enable readers to assess potential solar heating/cooling applications in specific geographical areas, and includes tools necessary to do a preliminary design of the system and to analyze its economic benefits. The following are included: the case for solar energy; solar radiation and weather; passive solar design; system characteristics and selection; component performance criteria; determining solar system thermal performance and economic feasibility; requirements, availability, and applications of solar heating systems; and sources of additional information.more » (MHR)« less

The Ultimate Destination: Choice of Interplanetary Exploration Path can define Future of Interstellar Spaceflight

NASA Astrophysics Data System (ADS)

Silin, D. V.

Manned interstellar spaceflight is facing multiple challenges of great magnitude; among them are extremely large distances and the lack of known habitable planets other than Earth. Many of these challenges are applicable to manned space exploration within the Solar System to the same or lesser degree. If these issues are resolved on an interplanetary scale, better position to pursue interstellar exploration can be reached. However, very little progress (if any) was achieved in manned space exploration since the end of Space Race. There is no lack of proposed missions, but all of them require considerable technological and financial efforts to implement while yielding no tangible benefits that would justify their costs. To overcome this obstacle highest priority in future space exploration plans should be assigned to the creation of added value in outer space. This goal can be reached if reductions in space transportation, construction and maintenance of space-based structures costs are achieved. In order to achieve these requirements several key technologies have to be mastered, such as near-Earth object mining, space- based manufacturing, agriculture and structure assembly. To keep cost and difficulty under control next exploration steps can be limited to nearby destinations such as geostationary orbit, low lunar orbit, Moon surface and Sun-Earth L1 vicinity. Completion of such a program will create a solid foundation for further exploration and colonization of the Solar System, solve common challenges of interplanetary and interstellar spaceflight and create useful results for the majority of human population. Another important result is that perception of suitable destinations for interstellar missions will change significantly. If it becomes possible to create habitable and self-sufficient artificial environments in the nearby interplanetary space, Earth-like habitable planets will be no longer required to expand beyond our Solar System. Large fraction of the stars in the observable Universe will become valid targets for interstellar missions.

Development of a Conceptual Structure for Architectural Solar Energy Systems.

ERIC Educational Resources Information Center

Ringel, Robert F.

Solar subsystems and components were identified and conceptual structure was developed for architectural solar energy heating and cooling systems. Recent literature related to solar energy systems was reviewed and analyzed. Solar heating and cooling system, subsystem, and component data were compared for agreement and completeness. Significant…

24 CFR 200.950 - Building product standards and certification program for solar water heating system.

Code of Federal Regulations, 2012 CFR

2012-04-01

... certification program for solar water heating system. 200.950 Section 200.950 Housing and Urban Development... solar water heating system. (a) Applicable standards. (1) All solar water heating systems shall be designed, manufactured, and tested in compliance with Solar Rating and Certification Corporation (SRCC...

24 CFR 200.950 - Building product standards and certification program for solar water heating system.

Code of Federal Regulations, 2013 CFR

2013-04-01

... certification program for solar water heating system. 200.950 Section 200.950 Housing and Urban Development... solar water heating system. (a) Applicable standards. (1) All solar water heating systems shall be designed, manufactured, and tested in compliance with Solar Rating and Certification Corporation (SRCC...

24 CFR 200.950 - Building product standards and certification program for solar water heating system.

Code of Federal Regulations, 2014 CFR

2014-04-01

... certification program for solar water heating system. 200.950 Section 200.950 Housing and Urban Development... solar water heating system. (a) Applicable standards. (1) All solar water heating systems shall be designed, manufactured, and tested in compliance with Solar Rating and Certification Corporation (SRCC...

Improving the Power Conversion Efficiency of Carbon Quantum Dot-Sensitized Solar Cells by Growing the Dots on a TiO₂ Photoanode In Situ.

PubMed

Zhang, Quanxin; Zhang, Geping; Sun, Xiaofeng; Yin, Keyang; Li, Hongguang

2017-05-31

Dye-sensitized solar cells (DSSCs) are highly promising since they can potentially solve global energy issues. The development of new photosensitizers is the key to fully realizing perspectives proposed to DSSCs. Being cheap and nontoxic, carbon quantum dots (CQDs) have emerged as attractive candidates for this purpose. However, current methodologies to build up CQD-sensitized solar cells (CQDSCs) result in an imperfect apparatus with extremely low power conversion efficiencies (PCEs). Herein, we present a simple strategy of growing carbon quantum dots (CQDs) onto TiO₂ surfaces in situ. The CQDs/TiO₂ hybridized photoanode was then used to construct solar cell with an improved PCE of 0.87%, which is higher than all of the reported CQDSCs adopting the simple post-adsorption method. This result indicates that an in situ growing strategy has great advantages in terms of optimizing the performance of CQDSCs. In addition, we have also found that the mechanisms dominating the performance of CQDSCs are different from those behind the solar cells using inorganic semiconductor quantum dots (ISQDs) as the photosensitizers, which re-confirms the conclusion that the characteristics of CQDs differ from those of ISQDs.

Oxidative degradation and toxicity reduction of trichloroethylene (TCE) in water using TiO2/solar light: comparative study of TiO2 slurry and immobilized systems.

PubMed

Cho, Il-Hyoung; Park, Jae-Hong; Kim, Young-Gyu

2005-01-01

A solar-driven, photocatalyzed degradation system using TiO2 slurry and immobilized systems was constructed and applied to the degradation of trichloroethylene (TCE) contaminated water using TiO2 with solar light. The experiments were carried out under constant weather conditions on a sunny day. Solar photocatalytic treatment efficiency of the solar light/TiO2 slurry system was compared with that of the solar light/TiO2 immobilized system. The operation of the solar light/TiO2 slurry and immobilized systems showed 100% (TiO2 slurry system), 80% (TiO2 immobilized system) degradation of the TCE after 6 h, with a chloride production yield of approximately 89% (TiO2 slurry system), 72% (TiO2 immobilized system). The oxidants such as H2O2 and S2O8(2-) in the TiO2 slurry and immobilized systems increased TCE degradation rate by suppressing the electron/hole recombination process. The degradation rate and relative toxicity reduction of TCE followed the order of solar light/TiO2 slurry + S2O8(2-) > solar light/TiO2 slurry + H2O2 > solar light/TiO2 immobilized + S2O8(2-) > solar light/TiO2 slurry > solar light/TiO2 immobilized + H2O2 > solar light/TiO2 immobilized. Finally, following to the toxicity result, the acute toxicity was reduced by below toxicity endpoint (EC50 concentration) following the treatment. It means that many of the metabolites of TCE reduction are less toxic to Vibrio fischeri than the parent compound. Based on these results, TCE can be efficiently and safely treated in a solar-driven, photocatalyzed degradation system.

Milky Way Mass Models and MOND

NASA Astrophysics Data System (ADS)

McGaugh, Stacy S.

2008-08-01

Using the Tuorla-Heidelberg model for the mass distribution of the Milky Way, I determine the rotation curve predicted by MOND (modified Newtonian dynamics). The result is in good agreement with the observed terminal velocities interior to the solar radius and with estimates of the Galaxy's rotation curve exterior thereto. There are no fit parameters: given the mass distribution, MOND provides a good match to the rotation curve. The Tuorla-Heidelberg model does allow for a variety of exponential scale lengths; MOND prefers short scale lengths in the range 2.0 kpc lesssim Rdlesssim 2.5 kpc. The favored value of Rd depends somewhat on the choice of interpolation function. There is some preference for the "simple" interpolation function as found by Famaey & Binney. I introduce an interpolation function that shares the advantages of the simple function on galaxy scales while having a much smaller impact in the solar system. I also solve the inverse problem, inferring the surface mass density distribution of the Milky Way from the terminal velocities. The result is a Galaxy with "bumps and wiggles" in both its luminosity profile and rotation curve that are reminiscent of those frequently observed in external galaxies.

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.

Some useful innovations with TRASYS and SINDA-85

NASA Technical Reports Server (NTRS)

Amundsen, Ruth M.

1993-01-01

Several innovative methods were used to allow more efficient and accurate thermal analysis using SINDA-85 and TRASYS, including model integration and reduction, planetary surface calculations, and model animation. Integration with other modeling and analysis codes allows an analyst to import a geometry from a solid modeling or computer-aided design (CAD) software package, rather than building the geometry 'by hand.' This is more efficient as well as potentially more accurate. However, the use of solid modeling software often generates large analytical models. The problem of reducing large models was elegantly solved using the response of the transient derivative to a forcing step function. The thermal analysis of a lunar rover implemented two unusual features of the TRASYS/SINDA system. A little-known TRASYS routine SURFP calculates the solar heating of a rover on the lunar surface for several different rover positions and orientations. This is used not only to determine the rover temperatures, but also to automatically determine the power generated by the solar arrays. The animation of transient thermal results is an effective tool, especially in a vivid case such as the 14-day progress of the sun over the lunar rover. An animated color map on the solid model displays the progression of temperatures.

GPS Attitude Determination Using Deployable-Mounted Antennas

NASA Technical Reports Server (NTRS)

Osborne, Michael L.; Tolson, Robert H.

1996-01-01

The primary objective of this investigation is to develop a method to solve for spacecraft attitude in the presence of potential incomplete antenna deployment. Most research on the use of the Global Positioning System (GPS) in attitude determination has assumed that the antenna baselines are known to less than 5 centimeters, or one quarter of the GPS signal wavelength. However, if the GPS antennas are mounted on a deployable fixture such as a solar panel, the actual antenna positions will not necessarily be within 5 cm of nominal. Incomplete antenna deployment could cause the baselines to be grossly in error, perhaps by as much as a meter. Overcoming this large uncertainty in order to accurately determine attitude is the focus of this study. To this end, a two-step solution method is proposed. The first step uses a least-squares estimate of the baselines to geometrically calculate the deployment angle errors of the solar panels. For the spacecraft under investigation, the first step determines the baselines to 3-4 cm with 4-8 minutes of data. A Kalman filter is then used to complete the attitude determination process, resulting in typical attitude errors of 0.50.

Numerical Study on Natural Vacuum Solar Desalination System with Varying Heat Source Temperature

NASA Astrophysics Data System (ADS)

Ambarita, H.

2017-03-01

A natural vacuum desalination unit with varying low grade heat source temperature is investigated numerically. The objective is to explore the effects of the variable temperature of the low grade heat source on performances and characteristics of the desalination unit. The specifications of the desalination unit are naturally vacuumed with surface area of seawater in evaporator and heating coil are 0.2 m2 and 0.188 m2, respectively. Temperature of the heating coil is simulated based on the solar radiation in the Medan city. A program to solve the governing equations in forward time step marching technique is developed. Temperature of the evaporator, fresh water production rate, and thermal efficiency of the desalination unit are analysed. Simulation is performed for 9 hours, it starts from 8.00 and finishes at 17.00 of local time. The results show that, the desalination unit with operation time of 9 hours can produce 5.705 L of freshwater and thermal efficiency is 81.8 %. This reveals that varying temperature of the heat source of natural vacuum desalination unit shows better performance in comparison with constant temperature of the heat source.

Computational modelling of cosmic rays in the neighbourhood of the Sun

NASA Astrophysics Data System (ADS)

Potgieter, M. S.; Strauss, R. D.

2017-10-01

The heliosphere is defned as the plasmatic inuence sphere of the Sun and stretches far beyond the solar system. Cosmic rays, as charged particles with energy between about 1 MeV and millions of GeV, arriving from our own Galaxy and beyond, penetrate the heliosphere and encounter the solar wind and embedded magnetic feld so that when observed they contain useful information about the basic features of the heliosphere. In order to interpret these observations, obtained on and near the Earth and farther away by several space missions, and to gain understanding of the underlying physics, called heliophysics, we need to simulate the heliosphere and the acceleration, propagation and transport of these astroparticles with numerical models. These types of models vary from magnetohydrodynamic based approaches for simulating the heliosphere to using standard fnite-difference numerical schemes to solve transport-type partial differential equations with varying complexity. A large number of these models have been developed locally to do internationally competitive research and have become as such an important training tool for human capacity development in computational physics in South Africa. How these models are applied to various aspects of heliospheric space physics, with illustrative examples, is discussed in this overview.

Paradigm transitions in solar-terrestrial physics from 1900: my personal view

NASA Astrophysics Data System (ADS)

Akasofu, S.-I.

2015-04-01

Solar-terrestrial physics, like any other scientific field, has evolved and developed by replacing older theories with newer theories. Unfortunately, each generation of young researchers tends to learn naturally only the latest, and perhaps the most popular theory and believes that it is the only useful one to pursue. Therefore, they do not necessarily realize that in the past the theory they chose had struggled to reach its presently acceptable state, and that eventually it might be replaced with a new theory. Two generations of scientists or in some subjects even more generations tend to be guided by one particular idea or theory. Thus, among us (namely, one or two generations) a high degree of agreement occurs, both on the theoretical assumptions and on the problem to be solved within the framework provided by the theory. Such an idea or theory was termed paradigm by Kuhn (1970). The purpose of this article is to describe several examples of the transition of paradigms and ideas in the subjects of solar-terrestrial physics. The examples are subjects that experienced a paradigm change after prevailing in the field for a few generations and also some that are perhaps on the verge of the transition. The chosen subjects are (1) Stormer's single particle theory to Chapman's plasma theory (1907-1963), (2) the auroral zone to the auroral oval (1860-1971), (3) the closed to open magnetosphere (1931-1971), (4) the current system controversies (1918-1963) and (1964-present), (5) the fixed pattern concept to the concept of auroral/magnetospheric substorms (1935-1982), (6) the importance of the interplanetary magnetic field (IMF) in the development of geomagnetic storms (1905-1966), (7) the ring current: solar wind protons to oxygen ions from the ionosphere (1933-1977), (8) the storm-substorm controversy (1963-present), (9) substorm onset (1964-present), (10) solar flares (1958-present) and (11) sunspots (1961-present).

Correcting GOES-R Magnetometer Data for Stray Fields

NASA Technical Reports Server (NTRS)

Carter, Delano; Freesland, Douglas; Tadikonda, Sivakumar; Kronenwetter, Jeffrey; Todirita, Monica; Dahya, Melissa; Chu, Donald

2016-01-01

Time-varying spacecraft magnetic fields, i.e. stray fields, are a problem for magnetometer systems. While constant fields can be removed by calibration, stray fields are difficult to distinguish from ambient field variations. Putting two magnetometers on a long boom and solving for both the ambient and stray fields can help, but this gradiometer solution is more sensitive to noise than a single magnetometer. As shown here for the R-series Geostationary Operational Environmental Satellites (GOES-R), unless the stray fields are larger than the noise, simply averaging the two magnetometer readings gives a more accurate solution. If averaging is used, it may be worthwhile to estimate and remove stray fields explicitly. Models and estimation algorithms to do so are provided for solar array, arcjet and reaction wheel fields.

Curious kinetic behavior in silica polymorphs solves seifertite puzzle in shocked meteorite

PubMed Central

Kubo, Tomoaki; Kato, Takumi; Higo, Yuji; Funakoshi, Ken-ichi

2015-01-01

The presence of seifertite, one of the high-pressure polymorphs of silica, in achondritic shocked meteorites has been problematic because this phase is thermodynamically stable at more than ~100 GPa, unrealistically high-pressure conditions for the shock events in the early solar system. We conducted in situ x-ray diffraction measurements at high pressure and temperatures, and found that it metastably appears down to ~11 GPa owing to the clear difference in kinetics between the metastable seifertite and stable stishovite formations. The temperature-insensitive but time-sensitive kinetics for the formation of seifertite uniquely constrains that the critical shock duration and size of the impactor on differentiated parental bodies are at least ~0.01 s and ~50 to 100 m, respectively, from the presence of seifertite. PMID:26601182

Stellar pulsations in beyond Horndeski gravity theories

NASA Astrophysics Data System (ADS)

Sakstein, Jeremy; Kenna-Allison, Michael; Koyama, Kazuya

2017-03-01

Theories of gravity in the beyond Horndeski class recover the predictions of general relativity in the solar system whilst admitting novel cosmologies, including late-time de Sitter solutions in the absence of a cosmological constant. Deviations from Newton's law are predicted inside astrophysical bodies, which allow for falsifiable, smoking-gun tests of the theory. In this work we study the pulsations of stars by deriving and solving the wave equation governing linear adiabatic oscillations to find the modified period of pulsation. Using both semi-analytic and numerical models, we perform a preliminary survey of the stellar zoo in an attempt to identify the best candidate objects for testing the theory. Brown dwarfs and Cepheid stars are found to be particularly sensitive objects and we discuss the possibility of using both to test the theory.

The Georgians Experience Astronomy Research in Schools (GEARS) High School Galaxy Unit

NASA Astrophysics Data System (ADS)

Higdon, Sarah; Higdon, J.; Aguilar, J.

2012-01-01

The Georgians Experience Astronomy Research in Schools (GEARS) project aims to provide a rigorous and inquiry-based astronomy curriculum to GA's public schools. Exposure to data mining and research activities using the astronomy archives can be the trigger for the next generation of scientists, and it improves a student's ability to solve problems. Students then consolidate their findings and improve their communication skills by writing scientific reports and creating video presentations. The GEARS curriculum has units on the solar system, life in the Universe, stars, galaxies and cosmology. Here we present some of the activities in the Galaxy Unit. The GEARS material is freely available. Please email shigdon_AT_georgiasouthern.edu if you would like more details. NASA Grant NNX09AH83A through the GADOE funds this project.

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

Orange, N. Brice; Chesny, David L.; Gendre, Bruce

Solar variability investigations that include magnetic energy coupling are paramount to solving many key solar/stellar physics problems, particularly for understanding the temporal variability of magnetic energy redistribution and heating processes. Using three years of observations from the Solar Dynamics Observatory ’ s Atmospheric Imaging Assembly and Heliosemic Magnetic Imager, we measured radiative and magnetic fluxes from gross features and at full-disk scales, respectively. Magnetic energy coupling analyses support radiative flux descriptions via the plasma heating connectivity of dominant (magnetic) and diffuse components, specifically of the predominantly closed-field corona. Our work shows that this relationship favors an energetic redistribution efficiency acrossmore » large temperature gradients, and potentially sheds light on the long-standing issue of diffuse unresolved low corona emission. The close connection between magnetic energy redistribution and plasma conditions revealed by this work lends significant insight into the field of stellar physics, as we have provided possible means for probing distant sources in currently limited and/or undetectable radiation distributions.« less

Alternative energy sources

NASA Astrophysics Data System (ADS)

Todd, R. W.

1982-04-01

Renewable energy sources and their potential contribution for solving energy needs are presented. Centralized supply technologies include those alternative fuels derived from biomass using solar energy, (supplying 57% of the energy supply in some countries), and those using directly collected solar energy to manufacture a fuel. Fuel utilization effects can be doubled by using combined heat and power stations, and other major sources include wind, wave, tidal, and solar. In terms of local supply technology, wood burning appliances are becoming more popular, and methane is being used for heating and to fuel spark ignition engines. Geothermal low temperature heating exists worldwide at a capacity of 7.2 GW, supplying heat, particularly in Hungary, parts of the U.S.S.R., and Iceland, and a geothermal research program has been established in the United States. Sweden has a potential hydroelectric capacity of 600 MW, and the United States has a 100 GW capacity. Many of these technologies are already cost effective.

Graphene-Based Photocatalysts for CO2 Reduction to Solar Fuel.

PubMed

Low, Jingxiang; Yu, Jiaguo; Ho, Wingkei

2015-11-05

Recently, photocatalytic CO2 reduction for solar fuel production has attracted much attention because of its potential for simultaneously solving energy and global warming problems. Many studies have been conducted to prepare novel and efficient photocatalysts for CO2 reduction. Graphene, a two-dimensional material, has been increasingly used in photocatalytic CO2 reduction. In theory, graphene shows several remarkable properties, including excellent electronic conductivity, good optical transmittance, large specific surface area, and superior chemical stability. Attributing to these advantages, fabrication of graphene-based materials has been known as one of the most feasible strategies to improve the CO2 reduction performance of photocatalysts. This Perspective mainly focuses on the recent important advances in the fabrication and application of graphene-based photocatalysts for CO2 reduction to solar fuels. The existing challenges and difficulties of graphene-based photocatalysts are also discussed for future application.

Missing matter in the vicinity of the sun

NASA Technical Reports Server (NTRS)

Bahcall, John N.

1986-01-01

The Poisson and Vlasov equations are solved numerically for realistic Galaxy models which include multiple disk components, a Population II spheroid, and an unseen massive halo. The total amount of matter in the vicinity of the sun is determined by comparing the observed distributions of tracer stars, samples of F dwarfs, and K giants with the predictions of the Galaxy models. Results are obtained for a number of different assumed distributions of the unseen disk mass. For all the observed samples, typical models imply that about half of the mass in the solar vicinity must be in the form of unobserved matter. The volume density of unobserved material near the sun is about 0.1 solar mass/cu pc; the corresponding column density is about 30 solar mass/sq pc. This so far unseen material must be in a disk with an exponential scale height of less than 0.7 kpc.

SPIN: An Inversion Code for the Photospheric Spectral Line

NASA Astrophysics Data System (ADS)

Yadav, Rahul; Mathew, Shibu K.; Tiwary, Alok Ranjan

2017-08-01

Inversion codes are the most useful tools to infer the physical properties of the solar atmosphere from the interpretation of Stokes profiles. In this paper, we present the details of a new Stokes Profile INversion code (SPIN) developed specifically to invert the spectro-polarimetric data of the Multi-Application Solar Telescope (MAST) at Udaipur Solar Observatory. The SPIN code has adopted Milne-Eddington approximations to solve the polarized radiative transfer equation (RTE) and for the purpose of fitting a modified Levenberg-Marquardt algorithm has been employed. We describe the details and utilization of the SPIN code to invert the spectro-polarimetric data. We also present the details of tests performed to validate the inversion code by comparing the results from the other widely used inversion codes (VFISV and SIR). The inverted results of the SPIN code after its application to Hinode/SP data have been compared with the inverted results from other inversion codes.

Application of Distributed DC/DC Electronics in Photovoltaic Systems

NASA Astrophysics Data System (ADS)

Kabala, Michael

In a typical residential, commercial or utility grade photovoltaic (PV) system, PV modules are connected in series and in parallel to form an array that is connected to a standard DC/AC inverter, which is then connected directly to the grid. This type of standard installation; however, does very little to maximize the energy output of the solar array if certain conditions exist. These conditions could include age, temperature, irradiance and other factors that can cause mismatch between PV modules in an array that severely cripple the output power of the system. Since PV modules are typically connected in series to form a string, the output of the entire string is limited by the efficiency of the weakest module. With PV module efficiencies already relatively low, it is critical to extract the maximum power out of each module in order to make solar energy an economically viable competitor to oil and gas. Module level DC/DC electronics with maximum power point (MPP) tracking solves this issue by decoupling each module from the string in order for the module to operate independently of the geometry and complexity of the surrounding system. This allows each PV module to work at its maximum power point by transferring the maximum power the module is able to deliver directly to the load by either boosting (stepping up) the voltage or bucking (stepping down) the voltage. The goal of this thesis is to discuss the development of a per-module DC/DC converter in order to maximize the energy output of a PV module and reduce the overall cost of the system by increasing the energy harvest.

Light harvesting proteins for solar fuel generation in bioengineered photoelectrochemical cells.

PubMed

Ihssen, Julian; Braun, Artur; Faccio, Greta; Gajda-Schrantz, Krisztina; Thöny-Meyer, Linda

2014-01-01

The sun is the primary energy source of our planet and potentially can supply all societies with more than just their basic energy needs. Demand of electric energy can be satisfied with photovoltaics, however the global demand for fuels is even higher. The direct way to produce the solar fuel hydrogen is by water splitting in photoelectrochemical (PEC) cells, an artificial mimic of photosynthesis. There is currently strong resurging interest for solar fuels produced by PEC cells, but some fundamental technological problems need to be solved to make PEC water splitting an economic, competitive alternative. One of the problems is to provide a low cost, high performing water oxidizing and oxygen evolving photoanode in an environmentally benign setting. Hematite, α-Fe2O3, satisfies many requirements for a good PEC photoanode, but its efficiency is insufficient in its pristine form. A promising strategy for enhancing photocurrent density takes advantage of photosynthetic proteins. In this paper we give an overview of how electrode surfaces in general and hematite photoanodes in particular can be functionalized with light harvesting proteins. Specifically, we demonstrate how low-cost biomaterials such as cyanobacterial phycocyanin and enzymatically produced melanin increase the overall performance of virtually no-cost metal oxide photoanodes in a PEC system. The implementation of biomaterials changes the overall nature of the photoanode assembly in a way that aggressive alkaline electrolytes such as concentrated KOH are not required anymore. Rather, a more environmentally benign and pH neutral electrolyte can be used.

Upper Limits for Power Yield in Thermal, Chemical, and Electrochemical Systems

NASA Astrophysics Data System (ADS)

Sieniutycz, Stanislaw

2010-03-01

We consider modeling and power optimization of energy converters, such as thermal, solar and chemical engines and fuel cells. Thermodynamic principles lead to expressions for converter's efficiency and generated power. Efficiency equations serve to solve the problems of upgrading or downgrading a resource. Power yield is a cumulative effect in a system consisting of a resource, engines, and an infinite bath. While optimization of steady state systems requires using the differential calculus and Lagrange multipliers, dynamic optimization involves variational calculus and dynamic programming. The primary result of static optimization is the upper limit of power, whereas that of dynamic optimization is a finite-rate counterpart of classical reversible work (exergy). The latter quantity depends on the end state coordinates and a dissipation index, h, which is the Hamiltonian of the problem of minimum entropy production. In reacting systems, an active part of chemical affinity constitutes a major component of the overall efficiency. The theory is also applied to fuel cells regarded as electrochemical flow engines. Enhanced bounds on power yield follow, which are stronger than those predicted by the reversible work potential.

Design of Light Trapping Solar Cell System by Using Zemax Program

NASA Astrophysics Data System (ADS)

Hasan, A. B.; Husain, S. A.

2018-05-01

Square micro lenses array have been designed (by using Zemax optical design program) to concentrate solar radiation into variable slits that reaching light to solar cell. This technique to increase the efficiency of solar system by trapping light due to internal reflection of light by mirrors that placed between upper and lower side of solar cell, therefore increasing optical path through the solar cell, and then increasing chance of photon absorption. The results show priority of solar system that have slit of (0.2 mm), and acceptance angle of (20°) that give acceptable efficiency of solar system.

Fundamentals and applications of solar energy. Part 2

NASA Astrophysics Data System (ADS)

Faraq, I. H.; Melsheimer, S. S.

Applications of techniques of chemical engineering to the development of materials, production methods, and performance optimization and evaluation of solar energy systems are discussed. Solar thermal storage systems using phase change materials, liquid phase Diels-Alder reactions, aquifers, and hydrocarbon oil were examined. Solar electric systems were explored in terms of a chlorophyll solar cell, the nonequilibrium electric field effects developed at photoelectrode/electrolyte interfaces, and designs for commercial scale processing of solar cells using continuous thin-film coating production methods. Solar coal gasification processes were considered, along with multilayer absorber coatings for solar concentrator receivers, solar thermal industrial applications, the kinetics of anaerobic digestion of crop residues to produce methane, and a procedure for developing a computer simulation of a solar cooling system.

THE CHROMOSPHERIC SOLAR LIMB BRIGHTENING AT RADIO, MILLIMETER, SUB-MILLIMETER, AND INFRARED WAVELENGTHS

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

De la Luz, V.

2016-07-10

Observations of the emission at radio, millimeter, sub-millimeter, and infrared wavelengths in the center of the solar disk validate the autoconsistence of semi-empirical models of the chromosphere. Theoretically, these models must reproduce the emission at the solar limb. In this work, we tested both the VALC and C7 semi-empirical models by computing their emission spectrum in the frequency range from 2 GHz to 10 THz at solar limb altitudes. We calculate the Sun's theoretical radii as well as their limb brightening. Non-local thermodynamic equilibrium was computed for hydrogen, electron density, and H{sup −}. In order to solve the radiative transfermore » equation, a three-dimensional (3D) geometry was employed to determine the ray paths, and Bremsstrahlung, H{sup −}, and inverse Bremsstrahlung opacity sources were integrated in the optical depth. We compared the computed solar radii with high-resolution observations at the limb obtained by Clark. We found that there are differences between the observed and computed solar radii of 12,000 km at 20 GHz, 5000 km at 100 GHz, and 1000 km at 3 THz for both semi-empirical models. A difference of 8000 km in the solar radii was found when comparing our results against the heights obtained from H α observations of spicules-off at the solar limb. We conclude that the solar radii cannot be reproduced by VALC and C7 semi-empirical models at radio—infrared wavelengths. Therefore, the structures in the high chromosphere provide a better measurement of the solar radii and their limb brightening as shown in previous investigations.« less

Development of Silver-Free Silicon Photovoltaic Solar Cells with All-Aluminum Electrodes

NASA Astrophysics Data System (ADS)

Sun, Wen-Cheng

To date, the most popular and dominant material for commercial solar cells is crystalline silicon (or wafer-Si). It has the highest cell efficiency and cell lifetime out of all commercial solar cells. Although the potential of crystalline-Si solar cells in supplying energy demands is enormous, their future growth will likely be constrained by two major bottlenecks. The first is the high electricity input to produce crystalline-Si solar cells and modules, and the second is the limited supply of silver (Ag) reserves. These bottlenecks prevent crystalline-Si solar cells from reaching terawatt-scale deployment, which means the electricity produced by crystalline-Si solar cells would never fulfill a noticeable portion of our energy demands in the future. In order to solve the issue of Ag limitation for the front metal grid, aluminum (Al) electroplating has been developed as an alternative metallization technique in the fabrication of crystalline-Si solar cells. The plating is carried out in a near-room-temperature ionic liquid by means of galvanostatic electrolysis. It has been found that dense, adherent Al deposits with resistivity in the high 10--6 Ω-cm range can be reproducibly obtained directly on Si substrates and nickel seed layers. An all-Al Si solar cell, with an electroplated Al front electrode and a screen-printed Al back electrode, has been successfully demonstrated based on commercial p-type monocrystalline-Si solar cells, and its efficiency is approaching 15%. Further optimization of the cell fabrication process, in particular a suitable patterning technique for the front silicon nitride layer, is expected to increase the efficiency of the cell to ~18%. This shows the potential of Al electroplating in cell metallization is promising and replacing Ag with Al as the front finger electrode is feasible.

Efecto de la difusión y la velocidad en la ionización del átomo de Carbono

NASA Astrophysics Data System (ADS)

Rovira, M. G.; Fontenla, J. M.

The equations of statistical equilibrium for all ionization states of the atom are solved. The effects of diffusion and center of mass velocity are included. In order to estimate the modifications of the ionization curves, they were applied to the Carbon atom. To solve these equations, solar prominences' models obtained in a previous paper were adopted. They were extended to reach a temperature of 1.5 × 106 K and the complete model of the prominence was calculated. Ionization curves for different values of velocity, diffusion and medium models were obtained. The different models represent structures with different densities. Considerable modifications due to these effects are found.

Arctic Ocean Tides from GRACE Satellite Accelerations

NASA Astrophysics Data System (ADS)

Killett, B.; Wahr, J. M.; Desai, S. D.; Yuan, D.; Watkins, M. M.

2010-12-01

Because missions such as TOPEX/POSEIDON don't extend to high latitudes, Arctic ocean tidal solutions aren't constrained by altimetry data. The resulting errors in tidal models alias into monthly GRACE gravity field solutions at all latitudes. Fortunately, GRACE inter-satellite ranging data can be used to solve for these tides directly. Seven years of GRACE inter-satellite acceleration data are inverted using a mascon approach to solve for residual amplitudes and phases of major solar and lunar tides in the Arctic ocean relative to FES 2004. Simulations are performed to test the inversion algorithm's performance, and uncertainty estimates are derived from the tidal signal over land. Truncation error magnitudes and patterns are compared to the residual tidal signals.

Thermal Storage Applications Workshop. Volume 2: Contributed Papers

NASA Technical Reports Server (NTRS)

1979-01-01

The solar thermal and the thermal and thermochemical energy storage programs are described as well as the technology requirements for both external (electrical) and internal (thermal, chemical) modes for energy storage in solar power plants. Specific technical issues addressed include thermal storage criteria for solar power plants interfacing with utility systems; optimal dispatch of storage for solar plants in a conventional electric grid; thermal storage/temperature tradeoffs for solar total energy systems; the value of energy storage for direct-replacement solar thermal power plants; systems analysis of storage in specific solar thermal power applications; the value of seasonal storage of solar energy; criteria for selection of the thermal storage system for a 10 MW(2) solar power plant; and the need for specific requirements by storage system development teams.

Communicating Solar System as experienced on March 29 TSE

NASA Astrophysics Data System (ADS)

Stavinschi, M.

The Earth becomes increasingly known as we explore the Solar System. The more answers we find on exoplanets, for instance, the better we know our planet. We discover many enigmas in the outer space and, surprisingly, solving them may lead to a higher perception of the land we are pacing. We must be aware of science news that means communicating valuable information to the public. As a consequence, a higher level of collaboration between scientists and science journalists is necessary. An informed and clever audience depends on their results. Our comment is focused on outreach of the last Total Solar Eclipse, from March 29 2006, an astronomical event that gathered around the same idea professional astronomers, and science journalists. Furthermore, even a cake shop has been involved and made for commercialization mini-eclipses cakes. If we cannot deliver the taste of the pastry, the free download soundtrack `Nobody Steals the Sun' may give the general public a sense of what is happening before, during, and after a solar eclipse. The Romanians witnessed different spectacular astronomical events such as the 1999 total solar eclipse and Venus transit. However, the latest TSE gives us a greater opportunity to find new ways of communicating the beauty of science to the public and to inform people about the Solar System. Even the eclipse doesn't happened on the Romanian territory, we managed to form mixed groups of professional and amateur astronomers, ordinary people and journalists, which traveled to Turkey for watching the eclipse. Most of them traveled by coach and had the opportunity to meet beautiful landscapes and know their history, and last but not in the least, to make friends. There were discussions from the scientific point of view that mixed with the curiosity of the participants. Moreover, sessions of popularizing the Sun and phenomenon among locals in different towns were such successful that the Turkish media - newspaper and TV - mentioned it. Scientists lectured at the national conference of Turkish physics teachers. Among the interviews, newspaper articles and radio programs given by professional astronomers there was an interesting musical experiment. It brought together a scientist, a composer and a science journalist. A young and talented composer wrote `Nobody Steals the Sun' soundtrack on the supervision of a professional astronomer. Based on an idea of a science journalist, C? t? lin Mosoia, and supervised by a professional astronomer, PhD Magda Stavinschi, the work of the Romanian composer Cristian Matei was produced taking into account the most important moments of a total eclipse of the Sun and its duration. Composed for non-commercial purposes only, it may be downloaded from the Astronomical Institute of the Romanian Academy website www.astro.ro. 2

Concentrated solar power generation using solar receivers

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

Anderson, Bruce N.; Treece, William Dean; Brown, Dan

Inventive concentrated solar power systems using solar receivers, and related devices and methods, are generally described. Low pressure solar receivers are provided that function to convert solar radiation energy to thermal energy of a working fluid, e.g., a working fluid of a power generation or thermal storage system. In some embodiments, low pressure solar receivers are provided herein that are useful in conjunction with gas turbine based power generation systems.

Fundamental (f) oscillations in a magnetically coupled solar interior-atmosphere system - An analytical approach

NASA Astrophysics Data System (ADS)

Pintér, Balázs; Erdélyi, R.

2018-01-01

Solar fundamental (f) acoustic mode oscillations are investigated analytically in a magnetohydrodynamic (MHD) model. The model consists of three layers in planar geometry, representing the solar interior, the magnetic atmosphere, and a transitional layer sandwiched between them. Since we focus on the fundamental mode here, we assume the plasma is incompressible. A horizontal, canopy-like, magnetic field is introduced to the atmosphere, in which degenerated slow MHD waves can exist. The global (f-mode) oscillations can couple to local atmospheric Alfvén waves, resulting, e.g., in a frequency shift of the oscillations. The dispersion relation of the global oscillation mode is derived, and is solved analytically for the thin-transitional layer approximation and for the weak-field approximation. Analytical formulae are also provided for the frequency shifts due to the presence of a thin transitional layer and a weak atmospheric magnetic field. The analytical results generally indicate that, compared to the fundamental value (ω =√{ gk }), the mode frequency is reduced by the presence of an atmosphere by a few per cent. A thin transitional layer reduces the eigen-frequencies further by about an additional hundred microhertz. Finally, a weak atmospheric magnetic field can slightly, by a few percent, increase the frequency of the eigen-mode. Stronger magnetic fields, however, can increase the f-mode frequency by even up to ten per cent, which cannot be seen in observed data. The presence of a magnetic atmosphere in the three-layer model also introduces non-permitted propagation windows in the frequency spectrum; here, f-mode oscillations cannot exist with certain values of the harmonic degree. The eigen-frequencies can be sensitive to the background physical parameters, such as an atmospheric density scale-height or the rate of the plasma density drop at the photosphere. Such information, if ever observed with high-resolution instrumentation and inverted, could help to gain further insight into solar magnetic structures by means of solar magneto-seismology, and could provide further insight into the role of magnetism in solar oscillations.

Solar Radiation and the UV Index: An Application of Numerical Integration, Trigonometric Functions, Online Education and the Modelling Process

ERIC Educational Resources Information Center

Downs, Nathan; Parisi, Alfio V.; Galligan, Linda; Turner, Joanna; Amar, Abdurazaq; King, Rachel; Ultra, Filipina; Butler, Harry

2016-01-01

A short series of practical classroom mathematics activities employing the use of a large and publicly accessible scientific data set are presented for use by students in years 9 and 10. The activities introduce and build understanding of integral calculus and trigonometric functions through the presentation of practical problem solving that…

The Baltimore applications project: A new look at technology transfer

NASA Technical Reports Server (NTRS)

1977-01-01

The history of cooperation between Goddard Space Flight Center and Baltimore City administrators in solving urban problems is summarized. NASA provided consultation and advisory services as well as technology resources and demonstrations. Research and development programs for 69 tasks are briefly described. Technology utilization for incinerator energy, data collection, Health Department problems, and solarization experiments are presented as case histories.

Surface- and interface-engineered heterostructures for solar hydrogen generation

NASA Astrophysics Data System (ADS)

Chen, Xiangyan; Li, Yanrui; Shen, Shaohua

2018-04-01

Photoelectrochemical (PEC) water splitting based on semiconductor photoelectrodes provides a promising platform for reducing environmental pollution and solving the energy crisis by developing clean, sustainable and environmentally friendly hydrogen energy. In this context, metal oxides with their advantages including low cost, good chemical stability and environmental friendliness, have attracted extensive attention among the investigated candidates. However, the large bandgap, poor charge transfer ability and high charge recombination rate limit the PEC performance of metal oxides as photoelectrodes. To solve this limitation, many approaches toward enhanced PEC water splitting performance, which focus on surface and interface engineering, have been presented. In this topical review, we concentrate on the heterostructure design of some typical metal oxides with narrow bandgaps (e.g. Fe2O3, WO3, BiVO4 and Cu2O) as photoelectrodes. An overview of the surface- and interface-engineered heterostructures, including semiconductor heterojunctions, surface protection, surface passivation and cocatalyst decoration, will be given to introduce the recent advances in metal oxide heterostructures for PEC water splitting. This article aims to provide fundamental references and principles for designing metal oxide heterostructures with high activity and stability as photoelectrodes for PEC solar hydrogen generation.

Dynamics of the solar wind and its interaction with bodies in the solar system

NASA Technical Reports Server (NTRS)

Spreiter, J. R.

1971-01-01

A discussion of the solar wind and its interaction with bodies of the solar system is presented. An overall unified account of the role of shock waves in the heating of the solar corona, the transmission of solar disturbances to the solar system, the flow fields of planets and natural satellites, and biological effects are provided. An analysis of magnetometer data from Explorer 33 and Vela 3A satellites to identify characteristics of solar wind shock waves is included.

Solar Design Workbook

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

Franta, G.; Baylin, F.; Crowther, R.

1981-06-01

This Solar Design Workbook presents solar building design applications for commercial buildir^s. The book is divided into four sections. The first section describes the variety of solar applications in buildings including conservation aspects, solar fundamentals, passive systems, active systems, daylighting, and other solar options. Solar system design evaluation techniques including considerations for building energy requirements, passive systems, active systems, and economics are presented in Section II. The third section attempts to assist the designer in the building design process for energy conservation and solar applications including options and considerations for pre-design, design, and post-design phases. The information required for themore » solar design proee^ has not been fully developed at this time. Therefore, Section III is incomplete, but an overview of the considerations with some of the design proces elements is presented. Section IV illustrates ease studies that utilize solar applications in the building design.« less

Solar-gas systems impact analysis study

NASA Astrophysics Data System (ADS)

Neill, C. P.; Hahn, E. F.; Loose, J. C.; Poe, T. E.; Hirshberg, A. S.; Haas, S.; Preble, B.; Halpin, J.

1984-07-01

The impacts of solar/gas technologies on gas consumers and on gas utilities were measured separately and compared against the impacts of competing gas and electric systems in four climatic regions of the U.S. A methodology was developed for measuring the benefits or penalties of solar/gas systems on a combined basis for consumers sand distribution companies. It is shown that the combined benefits associated with solar/gas systems are generally greatest when the systems are purchased by customers who would have otherwise chosen high-efficiency electric systems (were solar/gas systems not available in the market place). The role of gas utilities in encouraging consumer acceptance of solar/gas systems was also examined ion a qualitative fashion. A decision framework for analyzing the type and level of utility involvement in solar/gas technologies was developed.

A two-dimensional model of odd nitrogen in the thermosphere and mesosphere

NASA Technical Reports Server (NTRS)

Gerard, J. C.; Roble, R. G.; Rusch, D. W.

1980-01-01

Satellite measurements of the global nitric oxide distribution demonstrating the need for a two dimensional model of odd nitrogen photochemistry and transport in the thermosphere and mesosphere are reviewed. The main characteristics of a new code solving the transport equation for N(4S), N(2D), and N0 are given. This model extends from pole to pole between 75 and 275 km and reacts to the magnetic activity, the ultraviolet solar flux, and the neutral wind field. The effects of ionization and subsequent odd nitrogen production by high latitude particle precipitation are also included. Preliminary results are illustrated for a magnetically quiet solar minimum period with no neutral wind.

Progress on bioinspired, biomimetic, and bioreplication routes to harvest solar energy

NASA Astrophysics Data System (ADS)

Martín-Palma, Raúl J.; Lakhtakia, Akhlesh

2017-06-01

Although humans have long been imitating biological structures to serve their particular purposes, only a few decades ago engineered biomimicry began to be considered a technoscientific discipline with a great problem-solving potential. The three methodologies of engineered biomimicry-viz., bioinspiration, biomimetic, and bioreplication-employ and impact numerous technoscientific fields. For producing fuels and electricity by artificial photosynthesis, both processes and porous surfaces inspired by plants and certain marine animals are under active investigation. Biomimetically textured surfaces on the subwavelength scale have been shown to reduce the reflectance of photovoltaic solar cells over the visible and the near-infrared regimes. Lenticular compound lenses bioreplicated from insect eyes by an industrially scalable technique offer a similar promise.

Direct measurements of flux tube inclinations in solar plages.

NASA Astrophysics Data System (ADS)

Bernasconi, P. N.; Keller, C. U.; Povel, H. P.; Stenflo, J. O.

1995-10-01

Observations of the full Stokes vector in three spectral lines indicate that flux tubes in solar plages have an average inclination in the photosphere of 14^o^ with respect to the local vertical. Most flux tubes are inclined in the eastwards direction, i.e., opposite to the solar rotation. We have recorded the Stokes vector of the FeI 5247.1A, FeI 5250.2A, and FeI 5250.7A lines in nine different plages with the polarization-free 20cm Zeiss coronagraph at the Arosa Astrophysical Observatory of ETH Zuerich. The telescope has been modified for solar disk observations. The chosen spectral lines are particularly sensitive to magnetic field strength and temperature. To determine the field strength and geometry of the flux tubes in the observed plages we use an inversion code that numerically solves the radiative transfer equations and derives the emergent Stokes profiles for one-dimensional model atmospheres consisting of a flux tube and its surrounding non-magnetic atmosphere. Our results confirm earlier indirect estimates of the inclination of the magnetic fields in plages.

Internal stress-assisted epitaxial lift-off process for flexible thin film (In)GaAs solar cells on metal foil

NASA Astrophysics Data System (ADS)

Kim, Youngjo; Kim, Kangho; Jung, Sang Hyun; Kim, Chang Zoo; Shin, Hyun-Beom; Choi, JeHyuk; Kang, Ho Kwan

2017-12-01

Flexible thin film (In)GaAs solar cells are grown by metalorganic chemical vapor deposition on GaAs substrates and transferred to 30 μm thick Au foil by internal stress-assisted epitaxial lift-off processes. The internal stress is induced by replacing the solar cell epi-layers from GaAs to In0.015Ga0.985As, which has a slightly larger lattice constant. The compressive strained layer thickness was varied from 0 to 4.5 μm to investigate the influence of the internal stress on the epitaxial lift-off time. The etching time in the epitaxial lift-off process was reduced from 36 to 4 h by employing a GaAs/In0.015Ga0.985As heterojunction structure that has a compressive film stress of -59.0 MPa. We found that the partially strained epi-structure contributed to the much faster lateral etching rate with spontaneous bending. Although an efficiency degradation problem occurred in the strained solar cell, it was solved by optimizing the epitaxial growth conditions.

A Polytropic Model of the Solar Interior

NASA Astrophysics Data System (ADS)

Calvo-Mozo, B.; Buitrago Casas, J. C.; Martinez Oliveros, J. C.

2015-12-01

In this work we considered different processes in the solar interior that can be described using polytropes. This assumption implies a radially variable continuous polytropic exponent, that is, our model is a multi-polytropic model of the Sun. We derived the equations for this type of multi-polytropic structure and solved them using numerical integration methods. Both, the exponent and proportionality factor in the polytropic model equation of state were taken as input functions, for each spherical layer in the solar interior. Using the spatial distribution of the density and pressure terms from a solar standard model (SSM) we obtained the variable with depth polytropic exponents. We found that the radial distribution of these exponents show four different zones. These can be interpreted as a first region where the energy transport is controlled by radiation. The second region is defined by a sudden change in the polytropic index, which can be associated to the tachocline, followed by a region with a nearly constant polytropic index which suits well a convective zone. Finally, the exponent decreases radially at the photosphere.

Analysis of bias voltage dependent spectral response in Ga0.51In0.49P/Ga0.99In0.01As/Ge triple junction solar cell

NASA Astrophysics Data System (ADS)

Sogabe, Tomah; Ogura, Akio; Okada, Yoshitaka

2014-02-01

Spectral response measurement plays great role in characterizing solar cell device because it directly reflects the efficiency by which the device converts the sunlight into an electrical current. Based on the spectral response results, the short circuit current of each subcell can be quantitatively determined. Although spectral response dependence on wavelength, i.e., the well-known external quantum efficiency (EQE), has been widely used in characterizing multijunction solar cell and has been well interpreted, detailed analysis of spectral response dependence on bias voltage (SR -Vbias) has not been reported so far. In this work, we have performed experimental and numerical studies on the SR -Vbias for Ga0.51In0.49P/Ga0.99In0.01As/Ge triple junction solar cell. Phenomenological description was given to clarify the mechanism of operation matching point variation in SR -Vbias measurements. The profile of SR-Vbias curve was explained in detail by solving the coupled two-diode current-voltage characteristic transcend formula for each subcell.

Hybrids of Solar Sail, Solar Electric, and Solar Thermal Propulsion for Solar-System Exploration

NASA Technical Reports Server (NTRS)

Wilcox, Brian H.

2012-01-01

Solar sails have long been known to be an attractive method of propulsion in the inner solar system if the areal density of the overall spacecraft (S/C) could be reduced to approx.10 g/sq m. It has also long been recognized that the figure (precise shape) of useful solar sails needs to be reasonably good, so that the reflected light goes mostly in the desired direction. If one could make large reflective surfaces with reasonable figure at an areal density of approx.10 g/sq m, then several other attractive options emerge. One is to use such sails as solar concentrators for solar-electric propulsion. Current flight solar arrays have a specific output of approx. 100W/kg at 1 Astronomical Unit (AU) from the sun, and near-term advances promise to significantly increase this figure. A S/C with an areal density of 10 g/sq m could accelerate up to 29 km/s per year as a solar sail at 1 AU. Using the same sail as a concentrator at 30 AU, the same spacecraft could have up to approx. 45 W of electric power per kg of total S/C mass available for electric propulsion (EP). With an EP system that is 50% power-efficient, exhausting 10% of the initial S/C mass per year as propellant, the exhaust velocity is approx. 119 km/s and the acceleration is approx. 12 km/s per year. This hybrid thus opens attractive options for missions to the outer solar system, including sample-return missions. If solar-thermal propulsion were perfected, it would offer an attractive intermediate between solar sailing in the inner solar system and solar electric propulsion for the outer solar system. In the example above, both the solar sail and solar electric systems don't have a specific impulse that is near-optimal for the mission. Solar thermal propulsion, with an exhaust velocity of the order of 10 km/s, is better matched to many solar system exploration missions. This paper derives the basic relationships between these three propulsion options and gives examples of missions that might be enabled by such hybrids.

In situ Probe Science at Saturn

NASA Technical Reports Server (NTRS)

Atkinson, D.H.; Lunine, J.I.; Simon-Miller, A. A.; Atreya, S. K.; Brinckerhoff, W.; Colaprete, A.; Coustenis, A.; Fletcher, L. N.; Guillot, T.; Lebreton, J.-P.;

Solar heating and hot water system installed at Arlington Raquetball Club, Arlington, Virginia

NASA Technical Reports Server (NTRS)

1981-01-01

A solar space and water heating system is described. The solar energy system consists of 2,520 sq. ft. of flat plate solar collectors and a 4,000 gallon solar storage tank. The transfer medium in the forced closed loop is a nontoxic antifreeze solution (50 percent water, 50 percent propylene glycol). The service hot water system consists of a preheat coil (60 ft. of 1 1/4 in copper tubing) located in the upper third of the solar storage tank and a recirculation loop between the preheat coil and the existing electric water heaters. The space heating system consists of two separate water to air heat exchangers located in the ducts of the existing space heating/cooling systems. The heating water is supplied from the solar storage tank. Extracts from site files, specification references for solar modifications to existing building heating and hot water systems, and installation, operation and maintenance instructions are included.

An innovative deployable solar panel system for Cubesats

NASA Astrophysics Data System (ADS)

Santoni, Fabio; Piergentili, Fabrizio; Donati, Serena; Perelli, Massimo; Negri, Andrea; Marino, Michele

2014-02-01

One of the main Cubesat bus limitations is the available on-board power. The maximum power obtained using body mounted solar panels and advanced triple junction solar cells on a triple unit Cubesat is typically less than 10 W. The Cubesat performance and the mission scenario opened to these small satellite systems could be greatly enhanced by an increase of the available power. This paper describes the design and realization of a modular deployable solar panel system for Cubesats, consisting of a modular hinge and spring system that can be potentially used on-board single (1U), double(2U), triple (3U) and six units (6U) Cubesats. The size of each solar panels is the size of a lateral Cubesat surface. The system developed is the basis for a SADA (Solar Array Drive Assembly), in which a maneuvering capability is added to the deployed solar array in order to follow the apparent motion of the sun. The system design trade-off is discussed, comparing different deployment concepts and architectures, leading to the final selection for the modular design. A prototype of the system has been realized for a 3U Cubesat, consisting of two deployable solar panel systems, made of three solar panels each, for a total of six deployed solar panels. The deployment system is based on a plastic fiber wire and thermal cutters, guaranteeing a suitable level of reliability. A test-bed for the solar panel deployment testing has been developed, supporting the solar array during deployment reproducing the dynamical situation in orbit. The results of the deployment system testing are discussed, including the design and realization of the test-bed, the mechanical stress given to the solar cells by the deployment accelerations and the overall system performance. The maximum power delivered by the system is about 50.4 W BOL, greatly enhancing the present Cubesat solar array performance.

Solar cooling system performance, Frenchman's Reef Hotel, Virgin Islands

NASA Astrophysics Data System (ADS)

Harber, H.

1981-09-01

The operational and thermal performance of a variety of solar systems are described. The Solar Cooling System was installed in a hotel at St. Thomas, U. S. Virgin Islands. The system consists of the evacuated glass tube collectors, two 2500 gallon tanks, pumps, computerized controller, a large solar optimized industrial sized lithium bromide absorption chiller, and associated plumbing. Solar heated water is pumped through the system to the designed public areas such as lobby, lounges, restaurant and hallways. Auxiliary heat is provided by steam and a heat exchanger to supplement the solar heat.

Solar cooling system performance, Frenchman's Reef Hotel, Virgin Islands

NASA Technical Reports Server (NTRS)

Harber, H.

1981-01-01

The operational and thermal performance of a variety of solar systems are described. The Solar Cooling System was installed in a hotel at St. Thomas, U. S. Virgin Islands. The system consists of the evacuated glass tube collectors, two 2500 gallon tanks, pumps, computerized controller, a large solar optimized industrial sized lithium bromide absorption chiller, and associated plumbing. Solar heated water is pumped through the system to the designed public areas such as lobby, lounges, restaurant and hallways. Auxiliary heat is provided by steam and a heat exchanger to supplement the solar heat.

Sparse distributed memory overview

NASA Technical Reports Server (NTRS)

Raugh, Mike

1990-01-01

The Sparse Distributed Memory (SDM) project is investigating the theory and applications of massively parallel computing architecture, called sparse distributed memory, that will support the storage and retrieval of sensory and motor patterns characteristic of autonomous systems. The immediate objectives of the project are centered in studies of the memory itself and in the use of the memory to solve problems in speech, vision, and robotics. Investigation of methods for encoding sensory data is an important part of the research. Examples of NASA missions that may benefit from this work are Space Station, planetary rovers, and solar exploration. Sparse distributed memory offers promising technology for systems that must learn through experience and be capable of adapting to new circumstances, and for operating any large complex system requiring automatic monitoring and control. Sparse distributed memory is a massively parallel architecture motivated by efforts to understand how the human brain works. Sparse distributed memory is an associative memory, able to retrieve information from cues that only partially match patterns stored in the memory. It is able to store long temporal sequences derived from the behavior of a complex system, such as progressive records of the system's sensory data and correlated records of the system's motor controls.

Initial operation of a solar heating and cooling system in a full-scale solar building test facility

NASA Technical Reports Server (NTRS)

Knoll, R. H.; Miao, D.; Hamlet, I. L.; Jensen, R. N.

1976-01-01

The Solar Building Test Facility (SBTF) was constructed to advance the technology for heating and cooling of office buildings with solar energy. Its purposes are to (1) test system components which include high-performing collectors, (2) test the performance of a complete solar heating and cooling system, (3) investigate component interactions, and (4) investigate durability, maintenance and reliability of components. The SBTF consists of a 50,000 square foot office building modified to accept solar heated water for operation of an absorption air conditioner and for the baseboard heating system. A 12,666 square foot solar collector field with a 30,000 gallon storage tank provides the solar heated water. A description of the system and the collectors selected is printed along with the objectives, test approach, expected system performance, and some preliminary results.

Solar thermal electric hybridization issues

NASA Astrophysics Data System (ADS)

Williams, Tom A.; Bohn, Mark S.; Price, Henry W.

1994-10-01

Solar thermal electric systems have an advantage over many other renewable energy technologies because the former use heat as an intermediate energy carrier. This is an advantage, as it allows for a relatively simple method of hybridization by using heat from fossil-fuel. Hybridization of solar thermal electric systems is a topic that has recently generated significant interest and controversy and has led to many diverse opinions. This paper discusses many of the issues associated with hybridization of solar thermal electric systems such as what role hybridization should play; how it should be implemented; what are the efficiency, environmental, and cost implications; what solar fraction is appropriate; how hybrid systems compete with solar-only systems; and how hybridization can impact commercialization efforts for solar thermal electric systems.

Solar dynamic systems

NASA Technical Reports Server (NTRS)

Dustin, M. O.

1985-01-01

The development of the solar dynamic system is discussed. The benefits of the solar dynamic system over pv systems are enumerated. The history of the solar dynamic development is recounted. The purpose and approach of the advanced development are outlined. Critical concentrator technology and critical heat recover technology are examined.

Flat plate solar air heater with latent heat storage

NASA Astrophysics Data System (ADS)

Touati, B.; Kerroumi, N.; Virgone, J.

2017-02-01

Our work contains two parts, first is an experimental study of the solar air heater with a simple flow and forced convection, we can use thatlaste oneit in many engineering's sectors as solardrying, space heating in particular. The second part is a numerical study with ansys fluent 15 of the storage of part of this solar thermal energy produced,using latent heat by using phase change materials (PCM). In the experimental parts, we realize and tested our solar air heater in URER.MS ADRAR, locate in southwest Algeria. Where we measured the solarradiation, ambient temperature, air flow, thetemperature of the absorber, glasses and the outlet temperature of the solar air heater from the Sunrise to the sunset. In the second part, we added a PCM at outlet part of the solar air heater. This PCM store a part of the energy produced in the day to be used in peak period at evening by using the latent heat where the PCMs present a grateful storagesystem.A numerical study of the fusion or also named the charging of the PCM using ANSYS Fluent 15, this code use the method of enthalpies to solve the fusion and solidification formulations. Furthermore, to improve the conjugate heat transfer between the heat transfer fluid (Air heated in solar plate air heater) and the PCM, we simulate the effect of adding fins to our geometry. Also, four user define are write in C code to describe the thermophysicalpropriety of the PCM, and the inlet temperature of our geometry which is the temperature at the outflow of the solar heater.

Surface Experiments on a Jupiter Trojan Asteroid in the Solar Powered Sail Mission

NASA Astrophysics Data System (ADS)

Okada, Tatsuaki

2016-04-01

Introduction: A new mission to a Jupiter Trojan asteroid is under study us-ing a solar-powered sail (SPS), and a science lander is being investigated in the joint study between Japan and Europe [1]. We present here the key sci-entific objectives and the strawman payloads of science experiments on the asteroid. Science Objectives: Jupiter Trojan asteroids are located around the Sun-Jupiter Lagrange points (L4 or L5) and most of them are classified as D- or P-type in asteroid taxonomy, but their origin still remains unknown. A classi-cal (static) model of solar system evolution indicates that they were formed around the Jupiter region and survived until now as the outer end members of asteroids. A new (dynamical) model such as Nice model suggests that they were formed at the far end of the solar system and transferred inward due to dynamical migration of giant planets [2]. Therefore physical, miner-alogical, and isotopic studies of surface materials and volatile compounds could solve their origin, and then the solar system formation [3]. Strawman Payloads: The SPS orbiter will be able to carry a 100 kg class lander with 20 kg mission payloads. Just after landing of the lander, geolog-ical, mineralogical, and geophysical observations will be performed to char-acterize the site using a panoramic optical camera, an infrared hyperspectral imager, a magnetometer, and a thermal radiometer. The surface and subsur-face materials of the asteroid will be collected into a carousel by the bullet-type and the pneumatic drill type samplers, respectively. Samples in the carousel will be investigated by a visible and an infrared microscope, and transferred for performing high resolution mass spectrometry (HRMS). Mass resolution m/dm > 30,000 is expected to investigate isotopic ratios of D/H, 15N/14N, and 18O/16O, as well as molecules from organic matters. A set of strawman payloads are tentatively determined during the lander system study [4]. The constraints to select the strawman payloads have the total mass of 20 kg, and the total consumption energy of 600 WHr. In the SPS mission, the sample-return is also studied as an option, and the lander should bring the mechanisms for sample collection and sample transfer to the mother ship. [1] Mori O. et al. (2015) 11th Low-Cost Planetary Missions Conf., S3-10. [2] Morbidelli A. et al. (2005) Nature 435, 462-466. [3] Yano H. et al., (2014) CO-SPAR 2014, B0.4-2-14. [4] Mori O. et al., Lunar Planet. Sci. Conf., 47, #1822.

Influence of the solar wind and IMF on Jupiter's magnetosphere: Results from global MHD simulations

NASA Astrophysics Data System (ADS)

Sarkango, Y.; Jia, X.; Toth, G.; Hansen, K. C.

2017-12-01

Due to its large size, rapid rotation and presence of substantial internal plasma sources, Jupiter's magnetosphere is fundamentally different from that of the Earth. How and to what extent do the external factors, such as the solar wind and interplanetary magnetic field (IMF), influence the internally-driven magnetosphere is an open question. In this work, we solve the 3D semi-relativistic magnetohydrodynamic (MHD) equations using a well-established code, BATSRUS, to model the Jovian magnetosphere and study its interaction with the solar wind. Our global model adopts a non-uniform mesh covering the region from 200 RJ upstream to 1800 RJ downstream with the inner boundary placed at a radial distance of 2.5 RJ. The Io plasma torus centered around 6 RJ is generated in our model through appropriate mass-loading terms added to the set of MHD equations. We perform systematic numerical experiments in which we vary the upstream solar wind properties to investigate the impact of solar wind events, such as interplanetary shock and IMF rotation, on the global magnetosphere. From our simulations, we extract the location of the magnetopause boundary, the bow shock and the open-closed field line boundary (OCB), and determine their dependence on the solar wind properties and the IMF orientation. For validation, we compare our simulation results, such as density, temperature and magnetic field, to published empirical models based on in-situ measurements.

Space Weather: Where Is The Beef?

NASA Astrophysics Data System (ADS)

Koskinen, H. E. J.

Space weather has become a highly fashionable topic in solar-terrestrial physics. It is perhaps the best tool to popularise the field and it has contributed significantly to the dialogue between solar, magnetospheric, and ionospheric scientist, and also to mu- tual understanding between science and engineering communities. While these are laudable achievements, it is important for the integrity of scientific space weather re- search to recognise the central open questions in the physics of space weather and the progress toward solving them. We still lack sufficient understanding of the solar physics to be able to tell in advance when and where a solar eruption will take place and whether it will turn to a geoeffective event. There is much to do to understand ac- celeration of solar energetic particles and propagation of solar mass ejecta toward the Earth. After more than 40 years of research scientific discussion of energy and plasma transfer through the magnetopause still deals mostly with qualitative issues and the rapid acceleration processes in the magnetosphere are not yet explained in a satisfac- tory way. Also the coupling to the ionosphere and from there to the strong induction effects on ground is another complex of research problems. For space weather science the beef is in the investigation of these and related topics, not in marketing half-useful space weather products to hesitant customers.

The effect of random matter density perturbations on the large mixing angle solution to the solar neutrino problem

NASA Astrophysics Data System (ADS)

Guzzo, M. M.; Holanda, P. C.; Reggiani, N.

2003-08-01

The neutrino energy spectrum observed in KamLAND is compatible with the predictions based on the Large Mixing Angle realization of the MSW (Mikheyev-Smirnov-Wolfenstein) mechanism, which provides the best solution to the solar neutrino anomaly. From the agreement between solar neutrino data and KamLAND observations, we can obtain the best fit values of the mixing angle and square difference mass. When doing the fitting of the MSW predictions to the solar neutrino data, it is assumed the solar matter do not have any kind of perturbations, that is, it is assumed the the matter density monothonically decays from the center to the surface of the Sun. There are reasons to believe, nevertheless, that the solar matter density fluctuates around the equilibrium profile. In this work, we analysed the effect on the Large Mixing Angle parameters when the density matter randomically fluctuates around the equilibrium profile, solving the evolution equation in this case. We find that, in the presence of these density perturbations, the best fit values of the mixing angle and the square difference mass assume smaller values, compared with the values obtained for the standard Large Mixing Angle Solution without noise. Considering this effect of the random perturbations, the lowest island of allowed region for KamLAND spectral data in the parameter space must be considered and we call it very-low region.

Nashville Solar-Water-Heater Demonstration Project. Monitoring-data analysis

NASA Astrophysics Data System (ADS)

1982-03-01

Field monitoring data which were collected for the Nashville Solar Water Heater Demonstration Project from September through November of 1981 are presented. Twenty-six solar domestic water heaters were monitored during September, 35 during October, and 37 during November. Homeowners were audited to assure adequate solar access, and each selected a solar water heating system from an approved list. Two tank and one tank systems are included. The monitoring sample technique and monitoring system are described. Data are analyzed by computer to produce daily and monthly total summaries for each site. The performance of each site was assessed to compare total energy saved by the solar system, solar system savings percentage, and the energy multiplier.

A Solar Dynamic Power Option for Space Solar Power

NASA Technical Reports Server (NTRS)

Mason, Lee S.

1999-01-01

A study was performed to determine the potential performance and related technology requirements of Solar Dynamic power systems for a Space Solar Power satellite. Space Solar Power is a concept where solar energy is collected in orbit and beamed to Earth receiving stations to supplement terrestrial electric power service. Solar Dynamic systems offer the benefits of high solar-to-electric efficiency, long life with minimal performance degradation, and high power scalability. System analyses indicate that with moderate component development, SD systems can exhibit excellent mass and deployed area characteristics. Using the analyses as a guide, a technology roadmap was -enerated which identifies the component advances necessary to make SD power generation a competitive option for the SSP mission.

Application of solar energy; Proceedings of the Third Southeastern Conference, Huntsville, Ala., April 17-19, 1978

NASA Technical Reports Server (NTRS)

Wu, S. T. (Editor); Christensen, D. L.; Head, R. R.

1978-01-01

Demonstration projects, systems-subsystems simulation programs, applications (heating, cooling, agricultural, industrial), and climatic data testing (standards, economics, institutional) are the topics of the book. Economics of preheating water for commercial use and collecting, processing, and dissemination of data for the national demonstration program are discussed. Computer simulation of a solar energy system and graphical representation of solar collector performance are considered. Attention is given to solar driven heat pumps, solar cooling equipment, hybrid passive/active solar systems, and solar farm buildings. Evaluation of a thermographic scanning device for solar energy and conservation applications, use of meteorological data in system evaluation, and biomass conversion potential are presented.

Optical Waveguide Solar Energy System for Lunar Materials Processing

NASA Technical Reports Server (NTRS)

Nakamura, T.; Case, J. A.; Senior, C. L.

1997-01-01

This paper discusses results of our work on development of the Optical Waveguide (OW) Solar Energy System for Lunar Materials Processing. In the OW system as shown, solar radiation is collected by the concentrator which transfers the concentrated solar radiation to the OW transmission line consisting of low-loss optical fibers. The OW line transmits the solar radiation to the thermal reactor of the lunar materials processing plant. The feature of the OW system are: (1) Highly concentrated solar radiation (up to 104 suns) can be transmitted via flexible OW lines directly into the thermal reactor for materials processing: (2) Solar radiation intensity or spectra can be tailored to specific materials processing steps; (3) Provide solar energy to locations or inside of enclosures that would not otherwise have an access to solar energy; and (4) The system can be modularized and can be easily transported to and deployed at the lunar base.

A 15N-poor isotopic composition for the solar system as shown by Genesis solar wind samples.

PubMed

Marty, B; Chaussidon, M; Wiens, R C; Jurewicz, A J G; Burnett, D S

2011-06-24

The Genesis mission sampled solar wind ions to document the elemental and isotopic compositions of the Sun and, by inference, of the protosolar nebula. Nitrogen was a key target element because the extent and origin of its isotopic variations in solar system materials remain unknown. Isotopic analysis of a Genesis Solar Wind Concentrator target material shows that implanted solar wind nitrogen has a (15)N/(14)N ratio of 2.18 ± 0.02 × 10(-3) (that is, ≈40% poorer in (15)N relative to terrestrial atmosphere). The (15)N/(14)N ratio of the protosolar nebula was 2.27 ± 0.03 × 10(-3), which is the lowest (15)N/(14)N ratio known for solar system objects. This result demonstrates the extreme nitrogen isotopic heterogeneity of the nascent solar system and accounts for the (15)N-depleted components observed in solar system reservoirs.

Chaotic motion of comets in near-parabolic orbit: Mapping aproaches

NASA Astrophysics Data System (ADS)

Liu, Jie; Sun, Yi-Sui

1994-09-01

There exist many comets with near-parabolic orbits in the solar system. Among various theories proposed to explain their origin, the Oort cloud hypothesis seems to be the most reasonable. The theory assumes that there is a cometary cloud at a distance 103 to 107 from the sun and that perturbing forces from planets or stars make orbits of some of these comets become the near-parabolic type. Concerning the evolution of these orbits under planetary perturbations, we can raise the question: Will they stay in the solar system forever or will they escape from it? This is an attractive dynamical problem. If we go ahead by directly solving the dynamical differential equations, we may encounter the difficulty of long-time computation. For the orbits of these comets are near-parabolic and their periods are too long to study on their long-term evolution. With mapping approaches the difficulty will be overcome. In another aspect, the study of this model has special meaning for chaotic dynamics. We know that in the neighborhood of any separatrix i.e. the trajectory with zero frequency of the uperturbed motion of a Hamiltonian system, some chaotic motions have to be expected. Actually, the simplest example of separatrix is the parabolic trajectory of the two-body problem which separates the bounded and unbounded motion. From this point of view, the dynamical study of near-parabolic motion is very important. Petrosky's elegant but more abstract deduction gives a Kepler mapping which describes the dynamics of the cometary motion. In this paper we derive a similar mapping directly and discuss its dynamical characters.

Solar Systems

NASA Technical Reports Server (NTRS)

1979-01-01

The solar collectors shown are elements of domestic solar hot water systems produced by Solar One Ltd., Virginia Beach, Virginia. Design of these systems benefited from technical expertise provided Solar One by NASA's Langley Research Center. The company obtained a NASA technical support package describing the d e sign and operation of solar heating equipment in NASA's Tech House, a demonstration project in which aerospace and commercial building technology are combined in an energy- efficient home. Solar One received further assistance through personal contact with Langley solar experts. The company reports that the technical information provided by NASA influenced Solar One's panel design, its selection of a long-life panel coating which increases solar collection efficiency, and the method adopted for protecting solar collectors from freezing conditions.

Collection, processing and dissemination of data for the national solar demonstration program

NASA Technical Reports Server (NTRS)

Day, R. E.; Murphy, L. J.; Smok, J. T.

1978-01-01

A national solar data system developed for the DOE by IBM provides for automatic gathering, conversion, transfer, and analysis of demonstration site data. NASA requirements for this system include providing solar site hardware, engineering, data collection, and analysis. The specific tasks include: (1) solar energy system design/integration; (2) developing a site data acquisition subsystem; (3) developing a central data processing system; (4) operating the test facility at Marshall Space Flight Center; (5) collecting and analyzing data. The systematic analysis and evaluation of the data from the National Solar Data System is reflected in a monthly performance report and a solar energy system performance evaluation report.

The formation of the solar system

NASA Astrophysics Data System (ADS)

Pfalzner, S.; Davies, M. B.; Gounelle, M.; Johansen, A.; Münker, C.; Lacerda, P.; Portegies Zwart, S.; Testi, L.; Trieloff, M.; Veras, D.

2015-06-01

The solar system started to form about 4.56 Gyr ago and despite the long intervening time span, there still exist several clues about its formation. The three major sources for this information are meteorites, the present solar system structure and the planet-forming systems around young stars. In this introduction we give an overview of the current understanding of the solar system formation from all these different research fields. This includes the question of the lifetime of the solar protoplanetary disc, the different stages of planet formation, their duration, and their relative importance. We consider whether meteorite evidence and observations of protoplanetary discs point in the same direction. This will tell us whether our solar system had a typical formation history or an exceptional one. There are also many indications that the solar system formed as part of a star cluster. Here we examine the types of cluster the Sun could have formed in, especially whether its stellar density was at any stage high enough to influence the properties of today’s solar system. The likelihood of identifying siblings of the Sun is discussed. Finally, the possible dynamical evolution of the solar system since its formation and its future are considered.

Site selection feasibility for a solar energy system on the Fairbanks Federal Building

NASA Technical Reports Server (NTRS)

1978-01-01

A feasibility study was performed for the installation of a solar energy system on the Federal Building in Fairbanks, Alaska, a multifloor office building with an enclosed parking garge. The study consisted of determining the collectable solar energy at the Fairbanks site on a monthly basis and comparing this to the monthly building heating load. Potential conventional fuel savings were calculated on a monthly basis and the overall economics of the solar system applications were considered. Possible solar system design considerations, collector and other system installation details, interface of the solar system with the conventional HVAC systems, and possible control modes were all addressed. Conclusions, recommendations and study details are presented.

NREL, California Independent System Operator, and First Solar | Energy

Science.gov Websites

Solar NREL, California Independent System Operator, and First Solar Demonstrate Essential Reliability Services with Utility-Scale Solar NREL, the California Independent System Operator (CAISO), and First Solar conducted a demonstration project on a large utility-scale photovoltaic (PV) power plant in California to

75 FR 20376 - Notice of Availability of the Draft Environmental Impact Statement/Staff Assessment and Possible...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-19

... (1980, as amended), for the Calico Solar (formerly Stirling Energy Systems Solar One) Project, San... (LWCF). The project proposal includes building about 34,000, 25-kilowatt Stirling solar dish systems. Each solar dish system consists of an approximately 38-foot high by 40-foot wide solar concentrator...

Solar Program Assessment: Environmental Factors - Solar Total Energy Systems.

ERIC Educational Resources Information Center

Energy Research and Development Administration, Washington, DC. Div. of Solar Energy.

The purpose of this report is to present and prioritize the major environmental, safety, and social/institutional issues associated with the further development of Solar Total Energy Systems (STES). Solar total energy systems represent a specific application of the Federally-funded solar technologies. To provide a background for this analysis, the…

Modelling Solar Energetic Particle Propagation in Realistic Heliospheric Solar Wind Conditions Using a Combined MHD and Stochastic Differential Equation Approach

NASA Astrophysics Data System (ADS)

Wijsen, N.; Poedts, S.; Pomoell, J.

2017-12-01

Solar energetic particles (SEPs) are high energy particles originating from solar eruptive events. These particles can be energised at solar flare sites during magnetic reconnection events, or in shock waves propagating in front of coronal mass ejections (CMEs). These CME-driven shocks are in particular believed to act as powerful accelerators of charged particles throughout their propagation in the solar corona. After escaping from their acceleration site, SEPs propagate through the heliosphere and may eventually reach our planet where they can disrupt the microelectronics on satellites in orbit and endanger astronauts among other effects. Therefore it is of vital importance to understand and thereby build models capable of predicting the characteristics of SEP events. The propagation of SEPs in the heliosphere can be described by the time-dependent focused transport equation. This five-dimensional parabolic partial differential equation can be solved using e.g., a finite difference method or by integrating a set of corresponding first order stochastic differential equations. In this work we take the latter approach to model SEP events under different solar wind and scattering conditions. The background solar wind in which the energetic particles propagate is computed using a magnetohydrodynamic model. This allows us to study the influence of different realistic heliospheric configurations on SEP transport. In particular, in this study we focus on exploring the influence of high speed solar wind streams originating from coronal holes that are located close to the eruption source region on the resulting particle characteristics at Earth. Finally, we discuss our upcoming efforts towards integrating our particle propagation model with time-dependent heliospheric MHD space weather modelling.

Utilization of space technology for terrestrial solar power applications

NASA Technical Reports Server (NTRS)

Yasui, R. K.; Patterson, R. E.

1974-01-01

A description is given of the evolution of photovoltaic power systems designed and built for terrestrial applications, giving attention to problem areas which are currently impeding the further development of such systems. The rooftop testing of surplus solar panels is considered along with solar powered seismic observatories, solar powered portable radio sets, and design considerations identified from past experience. Present activities discussed are related to a solar powered on-shore beacon flasher system, a solar powered buoy, and a solar powered beacon flasher buoy.

Solar Advisor Model User Guide for Version 2.0

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

Gilman, P.; Blair, N.; Mehos, M.

2008-08-01

The Solar Advisor Model (SAM) provides a consistent framework for analyzing and comparing power system costs and performance across the range of solar technologies and markets, from photovoltaic systems for residential and commercial markets to concentrating solar power and large photovoltaic systems for utility markets. This manual describes Version 2.0 of the software, which can model photovoltaic and concentrating solar power technologies for electric applications for several markets. The current version of the Solar Advisor Model does not model solar heating and lighting technologies.

Simulation of DKIST solar adaptive optics system

NASA Astrophysics Data System (ADS)

Marino, Jose; Carlisle, Elizabeth; Schmidt, Dirk

2016-07-01

Solar adaptive optics (AO) simulations are a valuable tool to guide the design and optimization process of current and future solar AO and multi-conjugate AO (MCAO) systems. Solar AO and MCAO systems rely on extended object cross-correlating Shack-Hartmann wavefront sensors to measure the wavefront. Accurate solar AO simulations require computationally intensive operations, which have until recently presented a prohibitive computational cost. We present an update on the status of a solar AO and MCAO simulation tool being developed at the National Solar Observatory. The simulation tool is a multi-threaded application written in the C++ language that takes advantage of current large multi-core CPU computer systems and fast ethernet connections to provide accurate full simulation of solar AO and MCAO systems. It interfaces with KAOS, a state of the art solar AO control software developed by the Kiepenheuer-Institut fuer Sonnenphysik, that provides reliable AO control. We report on the latest results produced by the solar AO simulation tool.

Laser and solar-photovoltaic space power systems comparison. II.

NASA Technical Reports Server (NTRS)

De Young, R. J.; Stripling, J.; Enderson, T. M.; Humes, D. H.; Davis, W. T.

1984-01-01

A comparison of total system cost is made between solar photovoltaic and laser/receiver systems. The laser systems assume either a solar-pumped CO2 blackbody transfer laser with MHD receiver or a solar pumped liquid neodymium laser with a photovoltaic receiver. Total system costs are less for the laser systems below 300 km where drag is significant. System costs are highly dependent on altitude.

Prediction and warning system of SEP events and solar flares for risk estimation in space launch operations

NASA Astrophysics Data System (ADS)

García-Rigo, Alberto; Núñez, Marlon; Qahwaji, Rami; Ashamari, Omar; Jiggens, Piers; Pérez, Gustau; Hernández-Pajares, Manuel; Hilgers, Alain

2016-07-01

A web-based prototype system for predicting solar energetic particle (SEP) events and solar flares for use by space launch operators is presented. The system has been developed as a result of the European Space Agency (ESA) project SEPsFLAREs (Solar Events Prediction system For space LAunch Risk Estimation). The system consists of several modules covering the prediction of solar flares and early SEP Warnings (labeled Warning tool), the prediction of SEP event occurrence and onset, and the prediction of SEP event peak and duration. In addition, the system acquires data for solar flare nowcasting from Global Navigation Satellite Systems (GNSS)-based techniques (GNSS Solar Flare Detector, GSFLAD and the Sunlit Ionosphere Sudden Total Electron Content Enhancement Detector, SISTED) as additional independent products that may also prove useful for space launch operators.

Design and evaluation of a primary/secondary pumping system for a heat pump assisted solar thermal loop

NASA Astrophysics Data System (ADS)

Krockenberger, Kyle G.

A heat pump assisted solar thermal system was designed, commissioned, tested and analyzed over a period of two years. The unique system uses solar energy whenever it is available, but switches to heat pump mode at night or whenever there is a lack of solar energy. The solar thermal energy is added by a variety of flat plat solar collectors and an evacuated tube heat pipe solar collector. The working medium in the entire system is a 50% mixture of propylene glycol and water for freeze protection. During the design and evaluation the primary / secondary pumping system was the focus of the evaluation. Testing within this research focused on the operation modes, pump stability, and system efficiency. It was found that the system was in full operation, the pumps were stable and that the efficiency factor of the system was 1.95.

Performance and economics of residential solar space heating

NASA Astrophysics Data System (ADS)

Zehr, F. J.; Vineyard, T. A.; Barnes, R. W.; Oneal, D. L.

1982-11-01

The performance and economics of residential solar space heating were studied for various locations in the contiguous United States. Common types of active and passive solar heating systems were analyzed with respect to an average-size, single-family house designed to meet or exceed the thermal requirements of the Department of Housing and Urban Development Minimum Property Standards (HUD-MPS). The solar systems were evaluated in seventeen cities to provide a broad range of climatic conditions. Active systems evaluated consist of air and liquid flat plate collectors with single- and double-glazing: passive systems include Trombe wall, water wall, direct gain, and sunspace systems. The active system solar heating performance was computed using the University of Wisconsin's F-CHART computer program. The Los Alamos Scientific Laboratory's Solar Load Ratio (SLR) method was employed to compute solar heating performance for the passive systems. Heating costs were computed with gas, oil, and electricity as backups and as conventional heating system fuels.

Status review and prospects for solar industrial process heat (SIPH)

NASA Astrophysics Data System (ADS)

Kreith, F.; Davenport, R.; Feustel, J.

1983-11-01

Solar energy systems and components are presently available for industrial process hot air, hot water, and steam applications at temperatures up to about 300 C. Systems capable of operating at temperatures up to about 1000 C are approaching commercialization. A careful matching of the characteristics of the solar system and the industrial process in question has been found by field tests to be an important determinant of the amount of useful energy that can be delivered. While the thermal performance of solar collectors is not expected to improve significantly, better manufacturing, plumbing, and installation techniques may reduce both system and delivered energy costs significantly. Tax credits for solar installations, together with limited partnership financing, can offset the high initial cost of solar energy systems and provide equity between solar and fossil-fueled systems.

Adaptive, full-spectrum solar energy system

DOEpatents

Muhs, Jeffrey D.; Earl, Dennis D.

2003-08-05

An adaptive full spectrum solar energy system having at least one hybrid solar concentrator, at least one hybrid luminaire, at least one hybrid photobioreactor, and a light distribution system operably connected to each hybrid solar concentrator, each hybrid luminaire, and each hybrid photobioreactor. A lighting control system operates each component.

Hybrid PV/diesel solar power system design using multi-level factor analysis optimization

NASA Astrophysics Data System (ADS)

Drake, Joshua P.

Solar power systems represent a large area of interest across a spectrum of organizations at a global level. It was determined that a clear understanding of current state of the art software and design methods, as well as optimization methods, could be used to improve the design methodology. Solar power design literature was researched for an in depth understanding of solar power system design methods and algorithms. Multiple software packages for the design and optimization of solar power systems were analyzed for a critical understanding of their design workflow. In addition, several methods of optimization were studied, including brute force, Pareto analysis, Monte Carlo, linear and nonlinear programming, and multi-way factor analysis. Factor analysis was selected as the most efficient optimization method for engineering design as it applied to solar power system design. The solar power design algorithms, software work flow analysis, and factor analysis optimization were combined to develop a solar power system design optimization software package called FireDrake. This software was used for the design of multiple solar power systems in conjunction with an energy audit case study performed in seven Tibetan refugee camps located in Mainpat, India. A report of solar system designs for the camps, as well as a proposed schedule for future installations was generated. It was determined that there were several improvements that could be made to the state of the art in modern solar power system design, though the complexity of current applications is significant.

Energy from space; Proceedings of the Symposium on Solar Energy from Space, Vienna, Austria, August 9-21, 1982

NASA Astrophysics Data System (ADS)

Freeman, J. W.

Aspects of solar power generation in space are considered. The subjects discussed include: a vision of future energy from space; solar power satellite concept for utilization of energy from space; the institutional challenge of solar power satellites; system study of the solar power satellite concept; market potential and possible limitations for satellite solar power stations; financing a solar power satellite project; and European questions related to satellite power systems. Also addressed are: options and high payoff choices for transportation; an electric propulsion transportation system from low-earth orbit to geostationary orbit utilizing beamed microwave power; the Canadarm robot arm of the Shuttle Remote Manipulator System; an early experimental solar power satellite; power economical considerations for the integration of terrestrial and extraterrestrial solar generators into existing power generation stations; and space solar power in perspective. For individual items see A84-21477 to A84-21489

Control strategy of grid-connected photovoltaic generation system based on GMPPT method

NASA Astrophysics Data System (ADS)

Wang, Zhongfeng; Zhang, Xuyang; Hu, Bo; Liu, Jun; Li, Ligang; Gu, Yongqiang; Zhou, Bowen

2018-02-01

There are multiple local maximum power points when photovoltaic (PV) array runs under partial shading condition (PSC).However, the traditional maximum power point tracking (MPPT) algorithm might be easily trapped in local maximum power points (MPPs) and cannot find the global maximum power point (GMPP). To solve such problem, a global maximum power point tracking method (GMPPT) is improved, combined with traditional MPPT method and particle swarm optimization (PSO) algorithm. Under different operating conditions of PV cells, different tracking algorithms are used. When the environment changes, the improved PSO algorithm is adopted to realize the global optimal search, and the variable step incremental conductance (INC) method is adopted to achieve MPPT in optimal local location. Based on the simulation model of the PV grid system built in Matlab/Simulink, comparative analysis of the tracking effect of MPPT by the proposed control algorithm and the traditional MPPT method under the uniform solar condition and PSC, validate the correctness, feasibility and effectiveness of the proposed control strategy.

NASA Discusses Recent Testing of the James Webb Space Telescope

NASA Image and Video Library

2018-01-10

Members of the media were invited to NASA’s Johnson Space Center in Houston on Jan. 10, to hear about the results of recent cryogenic vacuum tests on the James Webb Space Telescope, and the next steps on the observatory’s path to space. Webb was tested as a complete optical system in Chamber A at Johnson, which mimics the space environment the telescope will experience during its mission. Built in 1965 to conduct thermal-vacuum testing on the Apollo command and service modules, Chamber A is the largest structure of its kind in the world and is a listed National Historic Landmark. The James Webb Space Telescope is the world’s premier infrared space observatory of the next decade. Webb will help to solve mysteries of our solar system, look to distant worlds orbiting other stars, and probe the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, the ESA (European Space Agency) and the Canadian Space Agency.

Effect of heat flux on differential rotation in turbulent convection.

PubMed

Kleeorin, Nathan; Rogachevskii, Igor

2006-04-01

We studied the effect of the turbulent heat flux on the Reynolds stresses in a rotating turbulent convection. To this end we solved a coupled system of dynamical equations which includes the equations for the Reynolds stresses, the entropy fluctuations, and the turbulent heat flux. We used a spectral tau approximation in order to close the system of dynamical equations. We found that the ratio of the contributions to the Reynolds stresses caused by the turbulent heat flux and the anisotropic eddy viscosity is of the order of approximately 10(L rho/l0)2, where l0 is the maximum scale of turbulent motions and L rho is the fluid density variation scale. This effect is crucial for the formation of the differential rotation and should be taken into account in the theories of the differential rotation of the Sun, stars, and planets. In particular, we demonstrated that this effect may cause the differential rotation which is comparable with the typical solar differential rotation.

Solar converter system with thermal overload protection

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

Popovich, J.M.; Thornbury, T.R.

1979-10-02

A solar energy conversion system comprises: (a) a solar converter in which liquid absorbs solar radiation, the liquid being solar energy absorptive; (b) first means to circulate said liquid for flow through the converter; and (c) means to effect removal of liquid from the converter in response to an undesirable operation condition in said system. 12 claims.

Solar photovoltaic research and development program of the Air Force Aero Propulsion Laboratory. [silicon solar cell applicable to satellite power systems

NASA Technical Reports Server (NTRS)

Wise, J.

1979-01-01

Progress is reported in the following areas: laser weapon effects, solar silicon solar cell concepts, and high voltage hardened, high power system technology. Emphasis is placed on solar cells with increased energy conversion efficiency and radiation resistance characteristics for application to satellite power systems.

DKIST Adaptive Optics System: Simulation Results

NASA Astrophysics Data System (ADS)

Marino, Jose; Schmidt, Dirk

2016-05-01

The 4 m class Daniel K. Inouye Solar Telescope (DKIST), currently under construction, will be equipped with an ultra high order solar adaptive optics (AO) system. The requirements and capabilities of such a solar AO system are beyond those of any other solar AO system currently in operation. We must rely on solar AO simulations to estimate and quantify its performance.We present performance estimation results of the DKIST AO system obtained with a new solar AO simulation tool. This simulation tool is a flexible and fast end-to-end solar AO simulator which produces accurate solar AO simulations while taking advantage of current multi-core computer technology. It relies on full imaging simulations of the extended field Shack-Hartmann wavefront sensor (WFS), which directly includes important secondary effects such as field dependent distortions and varying contrast of the WFS sub-aperture images.

Approaches to solar cell design for pulsed laser power receivers

NASA Technical Reports Server (NTRS)

Jain, Raj K.; Landis, Geoffrey A.

1993-01-01

Using a laser to beam power from Earth to a photovoltaic receiver in space could be a technology with applications to many space missions. Extremely high average-power lasers would be required in a wavelength range of 700-1000 nm. However, high-power lasers inherently operate in a pulsed format. Existing solar cells are not well designed to respond to pulsed incident power. To better understand cell response to pulsed illumination at high intensity, the PC-1D finite-element computer model was used to analyze the response of solar cells to continuous and pulsed laser illumination. Over 50 percent efficiency was calculated for both InP and GaAs cells under steady-state illumination near the optimum wavelength. The time-dependent response of a high-efficiency GaAs concentrator cell to a laser pulse was modeled, and the effect of laser intensity, wavelength, and bias point was studied. Three main effects decrease the efficiency of a solar cell under pulsed laser illumination: series resistance, L-C 'ringing' with the output circuit, and current limiting due to the output inductance. The problems can be solved either by changing the pulse shape or designing a solar cell to accept the pulsed input. Cell design possibilities discussed are a high-efficiency, light-trapping silicon cell, and a monolithic, low-inductance GaAs cell.

Review of the Potential of the Ni/Cu Plating Technique for Crystalline Silicon Solar Cells

PubMed Central

Rehman, Atteq ur; Lee, Soo Hong

2014-01-01

Developing a better method for the metallization of silicon solar cells is integral part of realizing superior efficiency. Currently, contact realization using screen printing is the leading technology in the silicon based photovoltaic industry, as it is simple and fast. However, the problem with metallization of this kind is that it has a lower aspect ratio and higher contact resistance, which limits solar cell efficiency. The mounting cost of silver pastes and decreasing silicon wafer thicknesses encourages silicon solar cell manufacturers to develop fresh metallization techniques involving a lower quantity of silver usage and not relying pressing process of screen printing. In recent times nickel/copper (Ni/Cu) based metal plating has emerged as a metallization method that may solve these issues. This paper offers a detailed review and understanding of a Ni/Cu based plating technique for silicon solar cells. The formation of a Ni seed layer by adopting various deposition techniques and a Cu conducting layer using a light induced plating (LIP) process are appraised. Unlike screen-printed metallization, a step involving patterning is crucial for opening the masking layer. Consequently, experimental procedures involving patterning methods are also explicated. Lastly, the issues of adhesion, back ground plating, process complexity and reliability for industrial applications are also addressed. PMID:28788516

A Solar Volumetric Receiver: Influence of Absorbing Cells Configuration on Device Thermal Performance

NASA Astrophysics Data System (ADS)

Yilbas, B. S.; Shuja, S. Z.

2017-01-01

Thermal performance of a solar volumetric receiver incorporating the different cell geometric configurations is investigated. Triangular, hexagonal, and rectangular absorbing cells are incorporated in the analysis. The fluid volume fraction, which is the ratio of the volume of the working fluid over the total volume of solar volumetric receiver, is introduced to assess the effect of cell size on the heat transfer rates in the receiver. In this case, reducing the fluid volume fraction corresponds to increasing cell size in the receiver. SiC is considered as the cell material, and air is used as the working fluid in the receiver. The Lambert's Beer law is incorporated to account for the solar absorption in the receiver. A finite element method is used to solve the governing equation of flow and heat transfer. It is found that the fluid volume fraction has significant effect on the flow field in the solar volumetric receiver, which also modifies thermal field in the working fluid. The triangular absorbing cell gives rise to improved effectiveness of the receiver and then follows the hexagonal and rectangular cells. The second law efficiency of the receiver remains high when hexagonal cells are used. This occurs for the fluid volume fraction ratio of 0.5.

Solar Imaging UV/EUV Spectrometers Using TVLS Gratings

NASA Technical Reports Server (NTRS)

Thomas, Roger J.

2003-01-01

It is a particular challenge to develop a stigmatic spectrograph for UV, EUV wavelengths since the very low normal-incidence reflectance of standard materials most often requires that the design be restricted to a single optical element which must simultaneously provide both reimaging and spectral dispersion. This problem has been solved in the past by the use of toroidal gratings with uniform line-spaced rulings (TULS). A number of solar extreme ultraviolet (EUV) spectrometers have been based on such designs, including SOHO/CDS, Solar-B/EIS, and the sounding rockets Solar Extreme ultraviolet Research Telescope and Spectrograph (SERTS) and Extreme Ultraviolet Normal Incidence Spectrograph (EUNIS). More recently, Kita, Harada, and collaborators have developed the theory of spherical gratings with varied line-space rulings (SVLS) operated at unity magnification, which have been flown on several astronomical satellite missions. We now combine these ideas into a spectrometer concept that puts varied-line space rulings onto toroidal gratings. Such TVLS designs are found to provide excellent imaging even at very large spectrograph magnifications and beam-speeds, permitting extremely high-quality performance in remarkably compact instrument packages. Optical characteristics of three new solar spectrometers based on this concept are described: SUMI and RAISE, two sounding rocket payloads, and NEXUS, currently being proposed as a Small-Explorer (SMEX) mission.

Review of the Potential of the Ni/Cu Plating Technique for Crystalline Silicon Solar Cells.

PubMed

Rehman, Atteq Ur; Lee, Soo Hong

2014-02-18

Developing a better method for the metallization of silicon solar cells is integral part of realizing superior efficiency. Currently, contact realization using screen printing is the leading technology in the silicon based photovoltaic industry, as it is simple and fast. However, the problem with metallization of this kind is that it has a lower aspect ratio and higher contact resistance, which limits solar cell efficiency. The mounting cost of silver pastes and decreasing silicon wafer thicknesses encourages silicon solar cell manufacturers to develop fresh metallization techniques involving a lower quantity of silver usage and not relying pressing process of screen printing. In recent times nickel/copper (Ni/Cu) based metal plating has emerged as a metallization method that may solve these issues. This paper offers a detailed review and understanding of a Ni/Cu based plating technique for silicon solar cells. The formation of a Ni seed layer by adopting various deposition techniques and a Cu conducting layer using a light induced plating (LIP) process are appraised. Unlike screen-printed metallization, a step involving patterning is crucial for opening the masking layer. Consequently, experimental procedures involving patterning methods are also explicated. Lastly, the issues of adhesion, back ground plating, process complexity and reliability for industrial applications are also addressed.

Interplanetary missions with the GDM propulsion system

NASA Astrophysics Data System (ADS)

Kammash, T.; Emrich, W.

1998-01-01

The Gasdynamic Mirror (GDM) fusion propulsion system utilizes a magnetic mirror machine in which a hot dense plasma is confined long enough to produce fusion energy while allowing a fraction of its charged particle population to escape from one end to generate thrust. The particles escaping through the opposite end have their energy converted to electric power which can be used to sustain the system in a steady state operation. With the aid of a power flow diagram the minimum demands on energy production can be established and the propulsive capability of the system can be determined by solving an appropriate set of governing equations. We apply these results to several missions within the solar system and compute the trip time by invoking a continuous burn, acceleration/deceleration type of trajectory with constant thrust and specific impulse. Ignoring gravitational effects of the planets or the sun, and neglecting the change in the Earth's position during the flight we compute the round trip time for missions from Earth to Mars, Jupiter, and Pluto using linear distances and certain payload fractions. We find that a round trip to Mars with the GDM rocket takes about 170 days while those to Jupiter and Pluto take 494 and 1566 days respectively.

Approach to simultaneously denoise and invert backscatter and extinction from photon-limited atmospheric lidar observations.

PubMed

Marais, Willem J; Holz, Robert E; Hu, Yu Hen; Kuehn, Ralph E; Eloranta, Edwin E; Willett, Rebecca M

2016-10-10

Atmospheric lidar observations provide a unique capability to directly observe the vertical column of cloud and aerosol scattering properties. Detector and solar-background noise, however, hinder the ability of lidar systems to provide reliable backscatter and extinction cross-section estimates. Standard methods for solving this inverse problem are most effective with high signal-to-noise ratio observations that are only available at low resolution in uniform scenes. This paper describes a novel method for solving the inverse problem with high-resolution, lower signal-to-noise ratio observations that are effective in non-uniform scenes. The novelty is twofold. First, the inferences of the backscatter and extinction are applied to images, whereas current lidar algorithms only use the information content of single profiles. Hence, the latent spatial and temporal information in noisy images are utilized to infer the cross-sections. Second, the noise associated with photon-counting lidar observations can be modeled using a Poisson distribution, and state-of-the-art tools for solving Poisson inverse problems are adapted to the atmospheric lidar problem. It is demonstrated through photon-counting high spectral resolution lidar (HSRL) simulations that the proposed algorithm yields inverted backscatter and extinction cross-sections (per unit volume) with smaller mean squared error values at higher spatial and temporal resolutions, compared to the standard approach. Two case studies of real experimental data are also provided where the proposed algorithm is applied on HSRL observations and the inverted backscatter and extinction cross-sections are compared against the standard approach.

In Situ Potassium-Argon Geochronology Using Fluxed Fusion and a Double Spike

NASA Technical Reports Server (NTRS)

Hurowitz, Joel A.; Hecht, Michael H.; Zimmerman, Wayne F.; Neidholdt, Evan L.; Sinha, Mahadeva P.; Sturhahn, Wolfgang; Coleman, Max; McCleese, Daniel J.; Farley, Kenneth A.; Eiler, John M.;

Stellar pulsations in beyond Horndeski gravity theories

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

Sakstein, Jeremy; Kenna-Allison, Michael; Koyama, Kazuya, E-mail: sakstein@physics.upenn.edu, E-mail: mka1g13@soton.ac.uk, E-mail: kazuya.koyama@port.ac.uk

Theories of gravity in the beyond Horndeski class recover the predictions of general relativity in the solar system whilst admitting novel cosmologies, including late-time de Sitter solutions in the absence of a cosmological constant. Deviations from Newton's law are predicted inside astrophysical bodies, which allow for falsifiable, smoking-gun tests of the theory. In this work we study the pulsations of stars by deriving and solving the wave equation governing linear adiabatic oscillations to find the modified period of pulsation. Using both semi-analytic and numerical models, we perform a preliminary survey of the stellar zoo in an attempt to identify themore » best candidate objects for testing the theory. Brown dwarfs and Cepheid stars are found to be particularly sensitive objects and we discuss the possibility of using both to test the theory.« less

Badhwar - O'Neill 2014 Galactic Cosmic Ray Flux Model Description

NASA Technical Reports Server (NTRS)

O'Neill, P. M.; Golge, S.; Slaba, T. C.

2014-01-01

The Badhwar-O'Neill (BON) Galactic Cosmic Ray (GCR) model is based on GCR measurements from particle detectors. The model has mainly been used by NASA to certify microelectronic systems and the analysis of radiation health risks to astronauts in space missions. The BON14 model numerically solves the Fokker-Planck differential equation to account for particle transport in the heliosphere due to diffusion, convection, and adiabatic deceleration under the assumption of a spherically symmetric heliosphere. The model also incorporates an empirical time delay function to account for the lag of the solar activity to reach the boundary of the heliosphere. This technical paper describes the most recent improvements in parameter fits to the BON model (BON14). Using a comprehensive measurement database, it is shown that BON14 is significantly improved over the previous version, BON11.

Short-term climatic fluctuations forced by thermal anomalies

NASA Technical Reports Server (NTRS)

Hanna, A. F.

1982-01-01

A two level, global, spectral model using pressure as a vertical coordinate was developed. The system of equations describing the model is nonlinear and quasi-geostrophic (linear balance). Static stability is variable in the model. A moisture budget is calculated in the lower layer only. Convective adjustment is used to avoid supercritical temperature lapse rates. The mechanical forcing of topography is introduced as a vertical velocity at the lower boundary. Solar forcing is specified assuming a daily mean zenith angle. The differential diabatic heating between land and sea is paramterized. On land and sea ice surfaces, a steady state thermal energy equation is solved to calculate the surface temperature. On the oceans, the sea surface temperature is specified as the climatological average for January. The model is used to simulate the January, February and March circulations.

A Fixed-point Scheme for the Numerical Construction of Magnetohydrostatic Atmospheres in Three Dimensions

NASA Astrophysics Data System (ADS)

Gilchrist, S. A.; Braun, D. C.; Barnes, G.

2016-12-01

Magnetohydrostatic models of the solar atmosphere are often based on idealized analytic solutions because the underlying equations are too difficult to solve in full generality. Numerical approaches, too, are often limited in scope and have tended to focus on the two-dimensional problem. In this article we develop a numerical method for solving the nonlinear magnetohydrostatic equations in three dimensions. Our method is a fixed-point iteration scheme that extends the method of Grad and Rubin ( Proc. 2nd Int. Conf. on Peaceful Uses of Atomic Energy 31, 190, 1958) to include a finite gravity force. We apply the method to a test case to demonstrate the method in general and our implementation in code in particular.

Reuniting the Solar System: Integrated Education and Public Outreach Projects for Solar System Exploration Missions and Programs

NASA Technical Reports Server (NTRS)

Lowes, Leslie; Lindstrom, Marilyn; Stockman, Stephanie; Scalice, Daniela; Klug, Sheri

2003-01-01

The Solar System Exploration Education Forum has worked for five years to foster Education and Public Outreach (E/PO) cooperation among missions and programs in order to leverage resources and better meet the needs of educators and the public. These efforts are coming together in a number of programs and products and in '2004 - The Year of the Solar System.' NASA's practice of having independent E/PO programs for each mission and its public affairs emphasis on uniqueness has led to a public perception of a fragmented solar system exploration program. By working to integrate solar system E/PO, the breadth and depth of the solar system exploration program is revealed. When emphasis is put on what missions have in common, as well as their differences, each mission is seen in the context of the whole program.

Assessment of solar-assisted gas-fired heat pump systems

NASA Technical Reports Server (NTRS)

Lansing, F. L.

1981-01-01

As a possible application for the Goldstone Energy Project, the performance of a 10 ton heat pump unit using a hybrid solar gas energy source was evaluated in an effort to optimize the solar collector size. The heat pump system is designed to provide all the cooling and/or heating requirements of a selected office building. The system performance is to be augmented in the heating mode by utilizing the waste heat from the power cycle. A simplified system analysis is described to assess and compute interrrelationships of the engine, heat pump, and solar and building performance parameters, and to optimize the solar concentrator/building area ratio for a minimum total system cost. In addition, four alternative heating cooling systems, commonly used for building comfort, are described; their costs are compared, and are found to be less competitive with the gas solar heat pump system at the projected solar equipment costs.

A regional comparison of solar, heat pump, and solar-heat pump systems

NASA Astrophysics Data System (ADS)

Manton, B. E.; Mitchell, J. W.

1982-08-01

A comparative study of the thermal and economic performance of the parallel and series solar heat pump systems, stand alone solar and stand alone heat pump systems for residential space and domestic hot water heating for the U.S. using FCHART 4.0 is presented. Results show that the parallel solar heat pump system yields the greatest energy savings in the south. Very low cost collectors (50-150 dollars/sq m) are required for a series solar heat pump system in order for it to compete economically with the better of the parallel or solar systems. Conventional oil or gas furnaces need to have a seasonal efficiency of at least 70-85% in order to save as much primary energy as the best primary system in the northeast. In addition, the implications of these results for current or proposed federal tax credit measures are discussed.

AlGaAs top solar cell for mechanical attachment in a multi-junction tandem concentrator solar cell stack

NASA Technical Reports Server (NTRS)

Dinetta, L. C.; Hannon, M. H.; Mcneely, J. B.; Barnett, A. M.

1991-01-01

The AstroPower self-supporting, transparent AlGaAs top solar cell can be stacked upon any well-developed bottom solar cell for improved system performance. This is an approach to improve the performance and scale of space photovoltaic power systems. Mechanically stacked tandem solar cell concentrator systems based on the AlGaAs top concentrator solar cell can provide near term efficiencies of 36 percent (AMO, 100x). Possible tandem stack efficiencies greater than 38 percent (100x, AMO) are feasible with a careful selection of materials. In a three solar cell stack, system efficiencies exceed 41 percent (100x, AMO). These device results demonstrate a practical solution for a state-of-the-art top solar cell for attachment to an existing, well-developed solar cell.

Solar heating and cooling demonstration project at Radian Corporation, Austin, Texas

NASA Technical Reports Server (NTRS)

1980-01-01

The solar heating and cooling system located at the Radian Corporation, Austin, Texas, is discussed. A technical description of the solar system is presented. The costs of the major components and the cost of installing the system are described. Flow diagrams and photographs of the solar system are provided.

75 FR 61509 - Notice of Issuance of Final Determination Concerning Solar Photovoltaic Panel Systems

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-05

... solar photovoltaic (``PV'') panel systems contain both U.S. and foreign-origin raw materials and... of origin of the solar PV panel system described above for the purposes of U.S. government... transformation has occurred; however, no one factor is determinative. In this case, the solar PV systems are...

Solar tracking system

DOEpatents

Okandan, Murat; Nielson, Gregory N.

2016-07-12

Solar tracking systems, as well as methods of using such solar tracking systems, are disclosed. More particularly, embodiments of the solar tracking systems include lateral supports horizontally positioned between uprights to support photovoltaic modules. The lateral supports may be raised and lowered along the uprights or translated to cause the photovoltaic modules to track the moving sun.

Elementary Students' Mental Models of the Solar System

ERIC Educational Resources Information Center

Calderon-Canales, Elena; Flores-Camacho, Fernando; Gallegos-Cazares, Leticia

2013-01-01

This research project aimed to identify and analyze Mexican primary school students' ideas about the components of the solar system. In particular, this study focused on conceptions of the solar system and representations of the dynamics of the solar system based on the functional and structural models that students make in school. Using a…

An Outline of the Solar System: Activities for the Elementary Student.

ERIC Educational Resources Information Center

Hartsfield, John, Comp.; Sellers, Millie, Comp.

This booklet provides information and five worksheets for elementary students studying the solar system. Fact sheets provide information on the sun, Mercury, Venus, Earth, Moon, Mars, asteroids, Jupiter, Saturn, Uranus, Neptune, Pluto, and comets. The worksheets are entitled: (1) Astronomical Unit; (2) Solar System Trivia; (3) Solar System Flash…

Solar energy in buildings: Implications for California energy policy

NASA Technical Reports Server (NTRS)

Hirshberg, A. S.; Davis, E. S.

1977-01-01

An assessment of the potential of active solar energy systems for buildings in California is summarized. The technology used for solar heating, cooling, and water heating in buildings is discussed. The major California weather zones and the solar energy designs are described, as well as the sizing of solar energy systems and their performance. The cost of solar energy systems is given both at current prices and at prices consistent with optimistic estimates for the cost of collectors. The main institutional barriers to the wide spread use of solar energy are summarized.

Conservation and solar energy program: congressional budget request, FY 1982

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

None

1981-01-01

Funding summaries are presented for the Conservation and Solar Energy Program funding information and program overview on energy conservation (Volume 7 of 7, DOE/CR-0011/2) are included for the Buildings and Community Systems, Industrial, Transportation; State and Local, Multi-Sector, Energy Impact Assistance, and Residential/Commercial retrofit programs. Funding information and program overviews on solar technology (Volume 2 of 7, DOE/CR-011/2) are included for Active and Passive Solar Heating and Cooling, Photovoltaics Energy Systems, Solar Thermal Power Systems, Biomass Energy Systems, Wind Energy Conversion Systems, Ocean Systems, Solar International Activities, Solar Information Systems, SERI Facility, MX-RES, Program Direction, and Alcohol Fuels programs. Informationmore » and overviews on energy production, demonstration, and distribution (Volume 6 of 7, DOE/CR-0011/2) are given for the solar program. A funding summary and a program overview are included for electrochemical and physical and chemical storage systems as appearing in DOE/CR-0011/2, Volume 3 of 7. Relevant tabulated data from the FY 1981. Request to the Congress are presented for Supplementals, Rescissions, and Deferrals. (MCW)« less

Solair heater program: solair applications study. Final report

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

Not Available

1977-12-01

General Electric has designed and tested a low-cost solar system using a vacuum tube solar air heater under ERDA Contract E(11-1)-2705. This contract extension has been provided to evaluate various applications of this solar collector. The evaluation identified attractive applications, evaluated corresponding control procedures, estimated system performance, compared economically insolation and insulation, and evaluated the repackaging of off-the-shelf equipment for improved cost effectiveness. The results of this study prompted General Electric's marketing group to do a detailed commercialization study of a residential domestic water heating system using the Solair concept which has been selected as the most attractive application. Othermore » attractive applications are space/domestic water heating and a heat pump assisted solar system/domestic water heating where the heat pump and the solar system function in parallel. A prime advantage of heated air solar systems over liquid systems is cost and longer life which results in higher BTU's/dollar. Other air system advantages are no liquid leakage problems, no toxicity of freezing problems, and less complicated equipment. A hybrid solar system has been identified that can improve the market penetration of solar energy. This system would use the existing mass of the house for energy storage thereby reducing solar cost and complexity. Adequate performance can be obtained with house temperature swings comparable to those used in nighttime setback of the thermostat. Details of this system are provided.« less

Benefit assessment of solar-augmented natural gas systems

NASA Technical Reports Server (NTRS)

Davis, E. S.; French, R. L.; Sohn, R. L.

1980-01-01

Report details how solar-energy-augmented system can reduce natural gas consumption by 40% to 70%. Applications discussed include: domestic hot water system, solar-assisted gas heat pumps, direct heating from storage tank. Industrial uses, solar-assisted appliances, and economic factors are discussed.

Hybrid solar lighting systems and components

DOEpatents

Muhs, Jeffrey D [Lenoir City, TN; Earl, Dennis D [Knoxville, TN; Beshears, David L [Knoxville, TN; Maxey, Lonnie C [Powell, TN; Jordan, John K [Oak Ridge, TN; Lind, Randall F [Lenoir City, TN

2007-06-12

A hybrid solar lighting system and components having at least one hybrid solar concentrator, at least one fiber receiver, at least one hybrid luminaire, and a light distribution system operably connected to each hybrid solar concentrator and each hybrid luminaire. A controller operates each component.

Towards a Self-Consistent Simulation Capability of Catastrophic Solar Energetic Particle Events

NASA Astrophysics Data System (ADS)

Sokolov, I.; Gombosi, T. I.; Bindi, V.; Borovikov, D.; Kota, J.; Giacalone, J.

2016-12-01

Space weather refers to variations in the space environment that can affect technologies or endanger human life and health. Solar energetic particle (SEP) events can affect communications and airline safety. Satellites are affected by radiation damage to electronics and to components that produce power and provide images. Sun and star sensors are blinded during large SEP events. Protons of ≳30 MeV penetrate spacesuits and spacecraft walls. Events, like that of August 4, 1972, would have been fatal to moon-walking astronauts. Catastrophic events typically are characterized by hard particle energy spectra potentially containing large fluxes of hundreds of MeV-GeV type particles. These super-energetic particles can penetrate even into the "safest" areas of spacecraft and produce induced radioactivity. We describe several technologies which are to be combined into a physics-based, self consistent model to understand and forecast the origin and evolution of SEP events: The Alfvén Wave Solar-wind Model (AWSoM) simulates the chromosphere-to-Earth system using separate electron and ion temperatures and separate parallel and perpendicular temperatures. It solves the energy equations including thermal conduction and coronal heating by Alfvén wave turbulence. It uses adaptive mesh refinement (AMR), which allows us to cover a broad range of spacial scales. The Eruptive Event Generator using the Gibson-Low flux-rope model (EEGGL) allows the user to select an active region on the sun, select the polarity inversion line where the eruption is observed, and insert a Gibson-Low flux-rope to produce eruption. The Multiple-Field-Lines-Advection Model for Particle Acceleration (M-FLAMPA) solves the particle transport equation along a multitude of interplanetary magnetic field lines originating from the Sun, using time-dependent parameters for the shock and magnetic field obtained from the MHD simulation. It includes a self-consistent coupling of Alfvén wave turbulence to the SEPs. M-FLAMPA takes into account the full dependence of the distribution function on the pitch-angle, as well as particle scattering by Alfvén wave turbulence. The M-FLAMPA model will be validated and constrained at high energies (125 MeV to many GeV) using the new Alpha Magnetic Spectrometer onboard the ISS.

Cleaner for Solar-Collector Covers

NASA Technical Reports Server (NTRS)

Frickland, P. O.; Cleland, E. L.

1983-01-01

Simple self-contained cleaning system proposed for solar collectors or solar-collector protective domes. Perforated transparent plastic cap attached to top of protective dome in heliostat solar-energy collection system distributes cleaning fluid over surface of dome without blocking significant fraction of solar radiation.

Organics and Ices in the Outer Solar System: Connections to the Interstellar Medium

NASA Technical Reports Server (NTRS)

Pendleton, Y. J.; Cruikshank, D. P.

2017-01-01

The solar nebula, that aggregate of gas and dust that formed the birthplace of the Sun, planets and plethora of small bodies comprising the Solar System, originated in a molecular cloud that is thought to have spawned numerous additional stars, some with their own planets and attendant small bodies. The question of the chemical and physical reprocessing of the original interstellar materials in the solar nebula has challenged both theory and observations. The acquisition and analysis of samples of comet and asteroid solids, and a growing suite of in-situ and close-up analyses of relatively unaltered small Solar System bodies now adds critical new dimensions to the study of the origin and evolution of the early solar nebula. Better understanding the original composition of the material from which our solar nebula formed, and the processing that material experienced, will aid in formulations of chemistry that might occur in other solar systems. While we seek to understand the compositional history of planetary bodies in our own Solar System, we will inevitably learn more about the materials that comprise exoplanets and their surrounding systems.

Advances in Solar Heating and Cooling Systems

ERIC Educational Resources Information Center

Ward, Dan S.

1976-01-01

Reports on technological advancements in the fields of solar collectors, thermal storage systems, and solar heating and cooling systems. Diagrams aid in the understanding of the thermodynamics of the systems. (CP)

Solar power generation system for reducing leakage current

NASA Astrophysics Data System (ADS)

Wu, Jinn-Chang; Jou, Hurng-Liahng; Hung, Chih-Yi

2018-04-01

This paper proposes a transformer-less multi-level solar power generation system. This solar power generation system is composed of a solar cell array, a boost power converter, an isolation switch set and a full-bridge inverter. A unipolar pulse-width modulation (PWM) strategy is used in the full-bridge inverter to attenuate the output ripple current. Circuit isolation is accomplished by integrating the isolation switch set between the solar cell array and the utility, to suppress the leakage current. The isolation switch set also determines the DC bus voltage for the full-bridge inverter connecting to the solar cell array or the output of the boost power converter. Accordingly, the proposed transformer-less multi-level solar power generation system generates a five-level voltage, and the partial power of the solar cell array is also converted to AC power using only the full-bridge inverter, so the power efficiency is increased. A prototype is developed to validate the performance of the proposed transformer-less multi-level solar power generation system.

Solar Energy Systems

NASA Astrophysics Data System (ADS)

1984-01-01

Calibrated in kilowatt hours per square meter, the solar counter produced by Dodge Products, Inc. provides a numerical count of the solar energy that has accumulated on a surface. Solar energy sensing, measuring and recording devices in corporate solar cell technology developed by Lewis Research Center. Customers for their various devices include architects, engineers and others engaged in construction and operation of solar energy facilities; manufacturers of solar systems or solar related products, such as glare reducing windows; and solar energy planners in federal and state government agencies.

Feasibility study of a 110 watt per kilogram lightweight solar array system

NASA Technical Reports Server (NTRS)

Shepard, N. F.; Stahle, C. V.; Hanson, K. L.; Schneider, A.; Blomstrom, L. E.; Hansen, W. T.; Kirpich, A.

1973-01-01

The feasibility of a 10,000 watt solar array panel which has a minimum power-to-mass ratio of 110 watt/kg is discussed. The application of this ultralightweight solar array to three possible missions was investigated. With the interplanetary mission as a baseline, the constraining requirements for a geosynchronous mission and for a manned space station mission are presented. A review of existing lightweight solar array system concepts revealed that changes in the system approach are necessary to achieve the specified 110 watt/kg goal. A comprehensive review of existing component technology is presented in the areas of thin solar cells, solar cell covers, welded interconnectors, substrates and deployable booms. Advances in the state-of-the-art of solar cell and deployable boom technology were investigated. System level trade studies required to select the optimum boom bending stiffness, system aspect ratio, bus voltage level, and solar cell circuit arrangement are reported. Design analysis tasks included the thermal analysis of the solar cell blanket, thermal stress analysis of the solar cell interconnectors/substrate, and the thermostructural loading of the deployed boom.

Advanced Methods for Incorporating Solar Energy Technologies into Electric Sector Capacity-Expansion Models: Literature Review and Analysis

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

Sullivan, P.; Eurek, K.; Margolis, R.

2014-07-01

Because solar power is a rapidly growing component of the electricity system, robust representations of solar technologies should be included in capacity-expansion models. This is a challenge because modeling the electricity system--and, in particular, modeling solar integration within that system--is a complex endeavor. This report highlights the major challenges of incorporating solar technologies into capacity-expansion models and shows examples of how specific models address those challenges. These challenges include modeling non-dispatchable technologies, determining which solar technologies to model, choosing a spatial resolution, incorporating a solar resource assessment, and accounting for solar generation variability and uncertainty.

Estimation of solar energy resources for low salinity water desalination in several regions of Russia

NASA Astrophysics Data System (ADS)

Tarasenko, A. B.; Kiseleva, S. V.; Shakun, V. P.; Gabderakhmanova, T. S.

2018-01-01

This paper focuses on estimation of demanded photovoltaic (PV) array areas and capital expenses to feed a reverse osmosis desalination unit (1 m3/day fresh water production rate). The investigation have been made for different climatic conditions of Russia using regional data on ground water salinity from different sources and empirical dependence of specific energy consumption on salinity and temperature. The most optimal results were obtained for Krasnodar, Volgograd, Crimea Republic and some other southern regions. Combination of salinity, temperature and solar radiation level there makes reverse osmosis coupled with photovoltaics very attractive to solve infrastructure problems in rural areas. Estimation results are represented as maps showing PV array areas and capital expenses for selected regions.

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.

Energy crisis: several ways to solve it

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

Fitzmorris, J.E. Jr.

There is no single way out of the energy crisis in a quick way, the author says. In discussing his views, Lt. Gov. Fitzmorris says the first step is to admit there is an energy crisis. Short- as well as long-term goals must be established, and crash programs (when necessary) should be used to develop sources of energy. Also, in the short run, more-effective energy imports and energy conservation should help. Even assuming substantial conservation measures, the nation will still require over one-third more energy in 1990 than today. Mr. Fitzmorris then reviews measures being practiced in his home statemore » of Louisiana that can bring some valuable time, but they cannot solve the basic problem; increased production of all types of energy is necessary for that. Energy companies and researchers in Louisiana are studying technology to gain energy from lignite, geopressured systems, hydrogen gas, ocean thermal difference, solar energy, biomass conversion, use of peat, and hydroelectric power. He says the two most steep and difficult paths out of the current energy quandry are to develop: (1) a national balance between the demands of energy development and environmental and (2) meaningful governmental deregulation at all levels, in deed as well as word. (MCW)« less