Browse Topic: Sun and solar

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An Online Coverage Path Planning Method for Sweeper Trucks in Dynamic Environments2021-01-00954/6/2021
In this paper, a novel online coverage path planning (CPP) method for autonomous sweeper trucks in closed areas is proposed. This method can efficiently generate executable paths for sweeper trucks that cover all feasible uncleaned areas without getting tracked in dead-end, i.e., no backward behaviors required and avoid dynamic obstacles. To reach that end, a modified biological inspired neuron network method considering vehicle constrains is developed, where the dynamic of each neuron is determined by the shunting function. The path will be iteratively generated based on local neuron dynamics. In order to avoid dead-end, a detour algorithm combing with back iteration is introduced to search the nearest uncleaned area that can be reached within vehicle constrains. The proposed method is empirically approved to be computationally efficient and adaptive to maps with arbitrary shapes. The feasibility of generated paths is validated in simulations, where the pure pursuit method is applied to achieve path following. The truck model in the simulation achieves 100% coverage with reasonable cross-track errors.
Zhang, Weiyang, Sun, Yong, Yu, Wenbo, XU, MENG
Products of Tomorrow: October 2019TBMG-3528610/1/2019
This column presents technologies that have applications in commercial areas, possibly creating the products of tomorrow. To learn more about each technology, see the contact information provided for that innovation.
Rose-Inspired Device Collects and Purifies WaterTBMG-3527610/1/2019
A new device, inspired by a rose, inexpensively collects and purifies water. The device is a new approach to solar steaming for water production — a technique that uses energy from sunlight to separate salt and other impurities from water through evaporation.
Ultraviolet Rays Quickly Bash Bacteria on Mobile DevicesTBMG-3534310/1/2019
Ultraviolet light has been used for more than 30 years as a source of disinfectant. A newly introduced product uses the technology to eliminate bacteria on cell phones, tablets and other mobile devices in 20 seconds, and is used worldwide in healthcare facilities, biotech manufacturing plants, and even food processing facilities.
Method Uses Ultraviolet Light to Control Fluid Flow and Organize ParticlesTBMG-349078/1/2019
A new method uses ultraviolet light to control the flow of fluids by encouraging particles — from plastic microbeads, to bacterial spores, to pollutants — to gather and organize at a specific location within a liquid and, if desired, move to new locations.
Revolutionary Camera Allows Scientists to Predict Evolution of Ancient StarsTBMG-347757/1/2019
Scientists at the University of Sheffield have been working with HiPERCAM, a high-speed, multicolor camera, which is capable of taking more than 1,000 images per second, allowing experts to measure both the mass and the radius of a cool subdwarf star for the first time.
Graphene Lid Extends Photoemission Electron Microscopy to LiquidsTBMG-347537/1/2019
By capping liquids with graphene (an ultrathin sheet of pure carbon), researchers can easily image and analyze liquid interfaces and the surface of nanometer-scale objects immersed in liquids. In the imaging technique known as photoemission electron microscopy (PEEM), ultraviolet light or X-rays bombard a sample, stimulating the material to release electrons from a region at or just beneath its surface. Electric fields act as lenses, focusing the emitted electrons to create an image.
Creation of an Icephobic Coating using Graphite Powder and PTFE Nanoparticles2019-01-19796/10/2019
Ice accretion can cause numerous inefficiencies, structural stresses, and failures in applications ranging from building design to power generation and aerospace applications. Currently, some of the leading de-icing technologies, such as the ICE-WIPS system, utilize a heating element coupled with a superhydrophobic surface. The high power consumption inherent in these systems can make them expensive and impractical, especially when coupled with power generating systems. Reduced power consumption in these de-icing technologies can be achieved through increased absorption of solar radiation in the visible range while maintaining hydrophobic performance of a coating. In this work, a Polytetrafluorethylene (PTFE) and graphite-based superhydrophobic surface is proposed, which maintains similar hydrophobic performance to standard superhydrophobic surfaces. The novel coating demonstrates contact angles of upwards of 130o and sliding angles of less than 4o, while increasing solar radiation absorption in the visible range by approximately 139% over PTFE-based hydrophobic coatings. Icing wind tunnel tests where the coatings were exposed to visible light in order to simulate solar radiation were performed in a variety of different conditions in order to verify the improved de-icing capabilities introduced by the added graphite. The melting time per unit ice mass was reduced by upwards of 50% for glaze ice and 8.0% for rime ice over a comparable de-icing coating without added graphite. There was also a qualitative difference in de-icing performance, as the coating with added graphite demonstrated removal of ice in a single sheet from the base layer, in contrast to the PTFE only coating, which allowed for the ice to melt in multiple pieces from the model.
Gonzales, Joseph, Sakaue, Hirotaka
Small-Body Dynamics Toolkit Version 5.0TBMG-339313/1/2019
The Small-Body Dynamics Toolkit (SBDT) v5.0 is a collection of primitive-body-specific trajectory design and analysis tools written in MATLAB®. The SBDT gives the user the capabilities to propagate, analyze, and visualize spacecraft trajectories and the dynamical environment near realistic asteroid, comet, or small planetary-moon models. The various component functions provided can be put together through user-created scripts, functions, or tools to perform a wide variety of trajectory analyses, including close-proximity encounter design, Monte Carlo studies, stability analysis, geometric analyses, and fuel budget calculations.
New Wristband Provides Personalized and Real-Time Tracking of UV ExposureTBMG-338893/1/2019
A paper-based sensor, which can be worn as a wristband, features happy and sad emoticon faces drawn in an invisible UV-sensitive ink. They successively light up as you reach 25%, 50%, 75%, and finally 100% of your daily recommended UV exposure. The research team also created six versions of the color-changing wristbands, each of which is personalized for a specific skin tone — an important characteristic given that darker people need more sun exposure to produce vitamin D, which is essential for healthy bones, teeth, and muscles.
Walking Robot Moves Without GPSTBMG-338702/27/2019
Ants are able to use polarized light and ultraviolet radiation to locate themselves in space. AntBot mimics this ability to explore its environment randomly and go home automatically, without GPS or mapping.
Printing Technology Uses Sound Waves to Control Size of Liquid DropletsTBMG-337022/1/2019
Liquid droplets are used in many applications, from printing ink on paper to creating microcapsules for drug delivery. Inkjet printing is the most common technique used to pattern liquid droplets, but it's only suitable for liquids that are roughly ten times more viscous than water. Many fluids of interest to researchers are far more viscous; for example, biopolymer and cell-laden solutions that are vital for biopharmaceuticals and bioprinting are at least 100 times more viscous than water. Some sugar-based biopolymers could be as viscous as honey, which is 25,000 times more viscous than water. The viscosity of these fluids also changes dramatically with temperature and composition, making it more difficult to optimize printing parameters to control droplet sizes.
5 Ws of My Skin Track UVTBMG-336782/1/2019
The device can optimize treatment of neonatal jaundice, skin diseases, and seasonal affective disorder (SAD) and reduce risk of sunburn and skin cancer.
Materials Move in Response to LightTBMG-335901/1/2019
In biology, there are many examples where light induces movement or change — think of flowers and leaves turning toward sunlight. Magnetic elastomeric composites were developed that move in different ways when exposed to light, raising the possibility that these materials could enable a wide range of products that perform simple to complex movements, from tiny engines and valves, to solar arrays that bend toward the sunlight. These simple movements could be combined into more complex motion like crawling, walking, or swimming, and can be triggered and controlled wirelessly using light.
Space Debris Orbit and Attitude Prediction for Enhanced and Efficient Space Situational AwarenessTBMG-3302510/1/2018
This research deals with the problem of modelling the orbit and attitude motion of uncontrolled manmade objects in orbit about the Earth, which tumble due to the natural influences of the near-Earth space environment. A mathematical, physics-based and computational approach is taken to model the forces and torques that drive the orbit and attitude evolution of such objects. The main influence modelled is solar radiation pressure (SRP), which is the interaction of solar electromagnetic radiation with the surface of an object, leading to both forces and torques that influence the orbital and attitude motion. Other influences, such as the gravitational field of the Earth, are also modelled.
Cobalt Oxygen-Evolving Catalysts for Clean Solar FuelTBMG-287124/1/2018
By splitting a water molecule into two atoms of hydrogen and one of oxygen, scientists can use the Sun’s energy to make a clean fuel. Splitting a water molecule requires a metal catalyst to get the reaction started. Recently, much scientific attention has focused on cobalt, a relatively abundant and inexpensive catalyst that — in the right circumstances — can serve as an escort to an electronic connection between hydrogens and oxygens.
Sensor Networks — The Platform for a Connected FarmTBMG-285263/1/2018
Farming has not been untouched by the IoT revolution. The relationships among field conditions, crops, and strategies for planting, irrigating, and harvesting are complex, yet vital for the success of the enterprise. Agricultural machines such as tractors, combines, mowers, and balers are key to smooth operations. Intelligent, addressable sensors on the machines and in the fields, enable farm managers to keep track of operations that are not only widely dispersed but also in motion.
Wearable Solar Thermoelectric GeneratorTBMG-283012/1/2018
Energy harvesting is a diverse field encompassing many technologies that involve a process that captures small amounts of energy that would otherwise be lost as heat, light, sound, vibration, or movement. A thermoelectric generator (TEG) is a device that converts waste heat energy — such as solar energy, geothermal energy, and body heat — into additional electrical power.
Custom Data Logger for Real-Time Remote Field Data Collections17AERP10_1010/1/2017
Compact, energy efficient instruments have the same functionality as a personal computer. Army Engineer Research and Development Center, Vicksburg, Mississippi The U.S. Army Corps of Engineers (USACE), CHL, FRF, had a need for a remote real-time data collection system to control instruments and log and communicate data from five observing stations in the Currituck Sound Estuary, NC1. These stations, referred to as the Currituck Sound Array (CSA), collect a suite of meteorological and oceanographic data including wind, air temperature, humidity, incoming solar radiation (above and below water), waves, currents, water level, salinity, and water temperature, as well as turbidity and many other water quality parameters. This array of instruments has a variety of control commands, sample routines, and output data formats. Additionally, the CSA was designed to act as a natural laboratory for estuarine research and as an instrument and model test bed. These capabilities required a reliable and flexible system that would allow easy modification of sampling schemes, the ability to log as many as 15 instruments with a single logger, and allow the incorporation of additional and novel instrumentation with minimal effort and expense. The custom loggers were built upon single board computers (SBC) running the Linux operating system. They effectively have the same functionality as a personal computer, overcoming many of the limitations of off-the-shelf loggers. Additionally, off-the-shelf loggers typically operate on a very limited set of commands. These custom Linux-based loggers have a much more diverse and powerful selection of commands, overcoming many of the unique challenges of real-time data collection with robust code and programmatic “watchdogs” that can automatically make sure the logger, instruments, and communications are operating as intended.
Custom Data Logger for Real-Time Remote Field Data CollectionsTBMG-2765310/1/2017
The U.S. Army Corps of Engineers (USACE), CHL, FRF, had a need for a remote real-time data collection system to control instruments and log and communicate data from five observing stations in the Currituck Sound Estuary, NC1. These stations, referred to as the Currituck Sound Array (CSA), collect a suite of meteorological and oceano-graphic data including wind, air temperature, humidity, incoming solar radiation (above and below water), waves, currents, water level, salinity, and water temperature, as well as turbidity and many other water quality parameters. This array of instruments has a variety of control commands, sample routines, and output data formats. Additionally, the CSA was designed to act as a natural laboratory for estuarine research and as an instrument and model test bed. These capabilities required a reliable and flexible system that would allow easy modification of sampling schemes, the ability to log as many as 15 instruments with a single logger, and allow the incorporation of additional and novel instrumentation with minimal effort and expense.
The Flying Carpet: Aerodynamic High-Altitude Solar Reflector Design Study2017-01-20269/19/2017
Our concept studies indicate that a set of reflectors floated in the upper atmosphere can efficiently reduce radiant forcing into the atmosphere. The cost of reducing the radiant forcing sufficiently to reverse the current rate of Global Warming, is well within reach of global financial resources. This paper summarizes the overall concept and focuses on one of the reflector concepts, the Flying Carpet. The basic element of this reflector array is a rigidized reflector sheet towed behind and above a solar-powered, distributed electric-propelled flying wing. The vehicle rises above 30,480 m (100,000 ft) in the daytime by solar power. At night, the very low wing loading of the sheets enables the system to stay well above the controlled airspace ceiling of 18,288 m (60,000 ft). The concept study results are summarized before going into technical issues in implementation. Flag instability is studied in initial wind tunnel experiments. This has forced evolution of the concept to one similar to a hang-glider, the sheet supporting the propelled wing at very low flight speed. Later designs may dispense with the wing altogether. Lift-induced drag can be minimized by joining several elements together in flight to create a large aspect ratio, and by staggering elements in flight as long-distance birds do, with swarm flight control. The primary parameter is the areal density that can be achieved for the reflector sheet under aerodynamic loads. Successful designs can be closed even with 2-mil Mylar sheets, but going to strengthened versions of solar sails would offer strong advantages. Mass-based cost estimation allows an upper bound on architecture cost by comparing equivalent number of launch masses of a well-known large space launch system. The next level of cost analysis shows that the manufacturing cost which is dominant, is best addressed through automotive industry techniques.
Komerath, Narayanan, Hariharan, Shravan, Shukla, Dhwanil, Patel, Sahaj, Rajendran, Vishnu, Hale, Emily
A Distributed Simulation of a Martian Fuel Production Facility2017-01-20229/19/2017
The future of human exploration in the solar system is contingent on the ability to exploit resources in-situ to produce mission consumables. Specifically, it has become clear that the success of a manned mission to Mars will likely depend on fuel components created on the Martian surface. While several architectures for an unmanned fuel production surface facility on Mars exist in theory, a simulation of the performance and operation of these architectures has not been created. In this paper, the framework describing a simulation of one such architecture is defined. Within this architecture, each component of the base is implemented as a state machine, with the ability to communicate with other base elements as well as a supervisor. An environment supervisor is also created which governs low level aspects of the simulation such as movement and resource distribution, in addition to higher-level aspects such as location selection with respect to operations specific behavior. This simulation will be implemented as an HLA (IEEE 1516e High Level Architecture) application, where each component of the base exists as a federate. A visualization of this simulation is created using a NASA visualization tool called DON (Distributed Observer Network). Metrics, such as fuel production throughput, are then cross validated against result data produced by a concurrent simulation project aiming to model the same scenario using different tools and methodology.
Loundy, Katherine, Schaefer, Louis, Foran, Andrew, Ninah, Catherine, Bandong, Khristopher, Brown, Robert, Heston, Hunter, Steed, John-Paul, Young, William, Heinrich, Mark, Rabelo, Luis
Tradeoff Study of High Altitude Solar Reflector Concepts2017-01-21439/19/2017
A direct solution to Global Warming would be to reflect a part of sunlight back into Space. A system tradeoff study is being developed with three of the concepts that are being evaluated as long-endurance high-altitude reflectors. The first concept is a high aspect ratio solar powered flying wing towing reflector sheets. This concept is named “Flying Carpet”. Second is a centrifugally stretched high altitude solar reflector (CSHASR). The CSHASR has 4 rotors made of reflector sheets with a hub stretching to 60 percent of the radius, held together by an ultralight quad-rotor structure. Each rotor is powered by a solar-electric motor. A variation on this concept, forced by nighttime descent rate concerns, is powered by tip-mounted solar panels and propellers with some battery storage augmenting rotational inertia as well as energy storage. The third concept is an Aerostatically Balanced Reflector (ABR) sheet, held up by hydrogen balloons. A set of co-axial counter-rotating rotors provides trim, directional control and migration with the summer Sun. This concept also offers the ability to hold up the reflector at arbitrary orientations to achieve maximum reflection, normal to the slanted rays of the polar summer sun. This paper presents concept evaluation and comparisons, explaining the concepts and high-level features of each concept in this extreme and little-explored regime of rotorcraft aeromechanics as well as aerostatics.
Komerath, Narayanan, Shukla, Dhwanil, Hariharan, Shravan, Patel, Sahaj, Hiremath, Nandeesh
Using Sunlight to Activate the Flow of Electrical Current in a New MaterialTBMG-275369/1/2017
Mined to make the first compass needles, the mineral magnetite is also made by migratory birds and other animals to allow them to sense north and south, and thus navigate in cloudy or dark atmospheric conditions or under water. Researchers have compositionally modified magnetite to capture visible sunlight and convert this light energy into electrical current. This current may be useful to drive the decomposition of water into hydrogen and oxygen. The team generated this material by replacing one third of the iron atoms with chromium atoms.
The Development of Direct Drive Motors for Solar Cars2017-01-12323/28/2017
Solar car races are held worldwide, aiming to promote vehicles that help reduce environmental loads on the roads. In order to gain superiority in solar car racing, it is essential to develop a high efficiency brushless direct drive motor that optimizes the energy use to the fullest and allows high speed driving when needed. To achieve these goals, two development approaches of solar car motors are proposed: the high efficiency motor which improves electrical characteristics and significantly reduces energy loss; and the variable field magnet motor that offers instant speed boost for a temporary period of time for overtaking opponents. We have developed a high efficiency motor through the application of an amorphous core and laminated magnets. Instead of the standard method of the W-EDM (Wire-Electric Discharge Machining) for amorphous cores, we utilized water jet cutting, through which we succeeded in achieving insulation between laminated cores. In general, a sheet of magnet is used in each slot and its dimension is determined according to the lamination height of the core. In this project, multiple magnet segments shorter in the direction of the shaft are stacked vertically to achieve the desired height, which successfully resulted in the reduction of iron loss. The application of these methods led to the achievement of motor efficiency exceeding 98%. For the instant speed increase, we have developed the optimized design configuration for a variable field magnet module that can change T-N characteristics, utilizing our unique method for varying the effective magnetic flux. The result shows that our variable field magnet motor achieved a 1.57 times higher rotational speed than conventional types. The proposed technologies can contribute to the efficient use of energy in solar car applications, promoting the development of novel solar car systems.
Yamazakii, Tsubasa, Uchiyama, Hidekazu, Nakazawa, Kazuaki, Isomura, Tsubasa, Ogata, Hisashi
Development Solar Charging System of Vehicle2017-01-15983/28/2017
Fuel consumption and CO2 emission regulations for vehicles, such as the Zero Emission Vehicle (ZEV) Regulation, motivate renewable energy technologies in the automotive industry. Therefore, the automotive industry is focused on adopting solar charging systems. Some vehicles have adopted solar energy to power the ventilation system, but these vehicles do not use solar energy to power the drivetrain. One important issue facing the design of solar charging systems is the low power generated by solar panels. Compared to solar panels for residential use, solar panels for vehicles can’t generate as much power because of size and weight limitations. Also, the power generated by solar panels can be extremely affected depending on differences in solar radiation among the cells. Therefore, Toyota has developed a solar charging system that can use solar energy for driving the Prius PHV. This system can efficiently charge the hybrid battery with the low power generated by the solar panel. The power generated can charge the hybrid battery while the vehicle is parked. Power can also be supplied from the hybrid battery to the auxiliary battery system during driving. The solar power contributes to the improvement of the electric driving range and the fuel consumption. This paper shows a solar charging system applied to a plug-in hybrid vehicle, a system configuration, operating modes, improving the standby power consumption of the system, and structure of solar panel.
Go, Koichi, Hirano, Takahiro, Miyoshi, Tatsuya, Sato, Daisuke
Variable Permeability Magnetometer Systems and Methods for Aerospace ApplicationsTBMG-263442/1/2017
NASA's Langley Research Center has developed a magnetometer that takes advantage of the unique variable permeability properties of Metglas 2714A magnetic material. By measuring directly the inductive reactance of a simple right circular cylindrical search coil through the application of current from a high-output-impedance current source driven with a 10-kHz sinusoidal voltage, a magnetic field sensor having a 700-Hz bandwidth, good linearity, and excellent noise performance with sensitivity at least as good as the 0.1 nTesla range was produced.
Apparatus and Method for a Light Direction SensorTBMG-263572/1/2017
This invention, developed at NASA's Goddard Space Flight Center, was originally conceived as a high-accuracy, high-sensitivity, bi-axial Sun angle sensor, but has also been proposed for applications involving the general field of precisely measuring the direction in which light travels toward the sensor. It has applications in spacecraft navigation, formation flying in space, space beacons, and automotive collision avoidance.
Mars Science Laboratory ChemCam Sun SafetyTBMG-261861/1/2017
The Mars Science Laboratory (MSL) ChemCam instrument can be damaged when the Sun enters or passes through its field of view (FOV). There is no Sun cover, yet other instruments mounted with boresights pointing in the same direction must observe the Sun for scientific observations and for attitude determination. When in a Suntolerant focus range during rover motion and pointing for observations by other remote sensing instruments, the Sun must be allowed to pass through the ChemCam FOV, and when in a Sun-damage focus range for ChemCam observations, the Sun must never be allowed to enter the FOV, even after a rover system fault. Both of these scenarios depend upon knowledge of the attitude of the rover relative to the motion of the Sun. A Sun search that is guaranteed to be Sun-safe for the ChemCam, even when the location of the Sun is unknown, had to be developed.
Method of Bonding Dissimilar MaterialsTBMG-2571011/1/2016
NASA’s Goddard Space Flight Center has developed a new method for bonding dissimilar materials using an elastic adhesive to permit the bond to withstand variations in temperature and pressure. Specifically, NASA uses this method to provide a >98% specular finish on composite materials that is proven capable of withstanding ultraviolet solar radiation exposure in a vacuum and thermal cycling from –115 °C to +65 °C, as well as meeting outgassing requirement limits of 1%.
Space Blanket-Inspired Cases Protect Expensive DevicesTBMG-246665/1/2016
In the 1960s, NASA was preparing for early forays into space, and worked to devise thin, reflective, metallic material to protect spacecraft from the dangers of solar radiation. This material — metallized polyethylene terephthalate (MPET) — is strong and not only reflects radiation, but also serves as powerful insulation to protect electronics from large swings in temperature.
Thermal Design & Analysis of Space-Craft for Lunar Descent and Operations.2016-01-02124/5/2016
TeamIndus is the only Indian participant in the Google Lunar X Prize (GLXP). GLXP, also referred to as Moon 2.0, is an inducement prize space competition organized by the X Prize Foundation, and sponsored by Google. The mission objective is to soft land a rover on moon, travel 500 meters and transmit HD videos and images to Earth. Team Indus’s strategy is to design and realize a lunar lander that will deliver a rover on to the surface of the moon which will accomplish GLXP mission objectives. The mission configuration comprises of four phases- Earth orbits, moon orbits, descent and surface operations. The lander during its interplanetary journey from earth to moon is exposed to different thermal loads viz. solar load, earth IR and albedo, moon IR and albedo, cold space at 4K and eclipse periods. The lander is also exposed to high temperatures of thruster nozzle during orbital transfer maneuvers. This paper discusses the thermal control system (TCS) that has been evolved to protect the lander during descent on to the surface of moon and operations to complete the mission objectives.
Kaushal, Paras, Wani, Satishchandra C.
SUV Solar Roof with Photo-Thermal Effect for Ventilation ORC System2016-01-02404/5/2016
The Organic Rankine Cycle System (ORC) is an effective means to use the solar energy. The system adopts the solar energy on the car roof as the heat source to make the ORC work and drive the thermoelectric air-conditioner. It can improve the entering comfort on the parking condition and the vehicle energy utilization efficiency. In this research, the system comprehensively applied the principle of sunshine concentration, heat collection and photo electricity. Then considering the working condition and performance features of ORC system, the car roof was designed to have a compact structure, through which the efficiency of the solar vehicle system could be improved. Firstly, the research analyzed the heat source temperature and the heat flux impact on the output power of the ORC system. After that, the performance of heat collection was identified according to the given thermoelectric air-condition’s power requirements. After building the model of three kinds of solar collectors, through the analysis and frequency division utilization of it, the basic requirements about stable output power by the solar energy could meet on the condition of different illumination. By the research and analysis, the ORC system could run normally and the output power was changed by sunlight’s condition with a certain scope of illuminance and a certain incident angle. Besides, the use of roof’s solar power could supply energy for a part of vehicle’s electric system and reduce energy consumption.
Zhan, Ruobing, Tan, Gangfeng, Yang, Bo, Zhang, Zhiwei, Wang, Tie, Liu, Cenyi, Wu, Xintong, Ren, Yanjun, Xu, Haobo
Solar Heat Load on the Vehicle Occupants2016-01-02464/5/2016
Vehicle occupants, unlike building occupants, are exposed to continuously varying, non-uniform solar heat load. Automotive manufacturers use photovoltaic cells based solar sensor to measure intensity and direction of the direct-beam solar radiation. Use of the time of the day and the position - latitude and longitude - of a vehicle is also common to calculate direction of the direct-beam solar radiation. Two angles - azimuth and elevation - are used to completely define the direction of solar radiation with respect to the vehicle coordinate system. Although the use of solar sensor is common in today’s vehicles, the solar heat load on the occupants, because of their exposure to the direct-beam solar radiation remains the area of in-car subjective evaluation and tuning. Since the solar rays travel in parallel paths, application of the ray tracing method to determine solar insolation of the vehicle occupants is possible. Calculating the solar exposure however requires the knowledge of geometry of the passenger compartment of a vehicle in addition to the direction of the direct-beam solar radiation. Geometry information includes 3D coordinates of the vehicle glasses and the passenger seating location. Planar surface approximation is used to represent both the glasses and the seats. Further the seat coordinates are shifted to obtain exposure of the occupants than the seats. Shifting of the seat coordinates is performed according to the thickness of chest and lap of an average adult. The solar exposure calculation also requires correction to the measured solar intensity. The correction is to account for attenuation of the solar radiation by the transmittance of the vehicle glasses. The solar heat load is then obtained by multiplying the occupant’s solar exposure area in m2 and the transmitted solar intensity in W/m2 for the given solar angles and vehicle geometry. The results of solar heat load so obtained are compared with the CFD Fluent data for a compact SUV.
Kakade, Rupesh Sonu, Mer, Prashant
Disturbance-Free, High-Resolution Imaging from SpaceTBMG-241223/1/2016
All imaging systems from space are affected by disturbances originating in the spacecraft in the form of mechanical noise from thruster and reaction/momentum wheels, and sensor noise. A drag-free system is truly unaffected by any disturbances, as it is in pure freefall. Hence, leveraging drag-free technology can provide a quantum leap in improvement for spaceborne imaging systems.
Thermal Cycle Qualification of Radiated Solar Arrays for 50 to 133 K Temperatures in VacuumTBMG-236891/1/2016
Solar arrays (radiated or non-radiated) and other technologies are candidate materials for projects in JPL. Some of the projects need to qualify these potential technologies to cryogenic extreme temperatures (from 133 to 50 K or lower). Those technologies need to survive for more than 120 thermal cycles in a thermal vacuum environment to meet three times mission life of the ECM project per JPL design principles. There is not any published thermal cycling qualification data for solar arrays in vacuum to those of cryogenic temperatures. Therefore, an experimental assessment study was undertaken on behalf of the JPL pre-project office for the proposed Europa Clipper mission.
Wide-Spectrum Organic Mass Spectrometer Using Far-Ultraviolet IonizationTBMG-236961/1/2016
Two-step laser desorption/photoionization mass spectrometry (L2MS) represents a powerful tool for the organic analysis of astromaterials. The technique has high sensitivity and requires little to no sample preparation.
Effect of Xylene Ratio on the Secondary Atomization with UV Laser2015-32-079611/17/2015
In our study, phenomena is observed that 30µm droplet become breakup by UV laser irradiation. This phenomena change by composition of droplet. Then we focused on difference of absorbance, hexadecane and o-xylene are used as fuel. The former do not absorb UV enough and the latter do absorb UV enough. And authors examined the relation mixing ratio and breakup phenomena using blended fuel which consist of hexadecane and o-xylene. With regard to the UV laser we used, wavelength is 266nm, flash of time is 10nsec and laser intensity is 15mJ. CCD camera, strobe light with 180nsec flash time and lens of ten magnification were used for observation. As a result, we obtained the following; 1) A state of breakup phenomena depend on concentration of o-xylene. 2) The absorbance is not related with a state of breakup phenomena.
Enomoto, Hiroshi, Iwafune, Naoki, Morii, Masaya, Honda, Ryo, Hieda, Noboru, Teraoka, Yoshikazu
Algorithm for Determining Solar Aspect from Images Generated by the HEROES MissionTBMG-2327311/1/2015
The goal of the High Energy Replicated Optics to Explore the Sun (HEROES) mission was to adapt an existing balloon payload, known as High Energy Replicated Optics (HERO), for solar observation. HERO used an on-axis star camera for fine aspect sensing, but this camera was too sensitive to be used when pointed near or toward the Sun. The pitch and yaw aspect system (PYAS) replaced the star camera during solar pointing. The PYAS used a computer vision algorithm to generate aspect solutions based on observations of a carefully constructed scene.
Conformal Nanotube Baffle for a Compact CoronagraphTBMG-2327711/1/2015
The development of a conformal nanotube process is enabling for many applications in solar physics and space astrophysics (e.g., direct detection and imaging of exoplanets). Coronagraphs are key heliophysics instruments because they image coronal mass ejections (CMEs), which are the most energetic phenomena on the Sun. CMEs have wide-ranging impact on the heliosphere, from interplanetary spacecraft to Earthorbiting satellites, communications, and astronaut safety; in short, they are major drivers of space weather. In a typical space-based coronagraph, an external occulter blocks light from the disk of the Sun so that the corona (about a million times dimmer) can be imaged. The occulter must suppress both diffracted light and stray light.
Modelling and Evaluation of Aircraft Contrails for 4-Dimensional Trajectory Optimisation2015-01-25389/15/2015
Contrails and aircraft-induced cirrus clouds are reputed being the largest components of aviation-induced global warming, even greater than carbon dioxide (CO2) exhaust emissions by aircraft. This article presents a contrail model algorithm specifically developed to be integrated within a multi-objective flight trajectory optimization software framework. The purpose of the algorithm is to supply to the optimizer a measure of the estimated radiative forcing from the contrails generated by the aircraft while flying a specific trajectory. In order to determine the precise measure, a comprehensive model is employed exploiting the Schmidt-Appleman criterion and ice-supersaturation regions. Additional parameters such as the solar zenith angle, contrail lifetime and spread are also considered. The optimization of flight trajectories encompassing such contrail model allows for selective avoidance of the positive radiative forcing conditions, such as only avoiding persistent contrails, or contrails which lead to negative radiative forcing. The model assesses the radiative forcing associated with 4-Dimensional (4D) trajectories in a 4D weather field, encompassing both the local time-of-day and the contrail lifetime. Some preliminary algorithm validation activities are presented, including a simulation case study involving a medium-range domestic flight of a turbofan aircraft from Melbourne to Brisbane.
Lim, Yixiang, Gardi, Alessandro, Sabatini, Roberto
Flight Proving a Heliophysics Soft X-Ray ImagerTBMG-223947/1/2015
The interaction between the solar wind and the Earth’s magneto - sphere results in “space weather.” To determine the true nature of the solar wind-magnetosphere interaction, scientists require global measurements of processes occurring at the bow shock, in the magnetosheath, and at the magnetopause. Such observations can only be obtained from imaging this interaction globally. This will produce a paradigm shift similar to how satellite imaging revolutionized terrestrial weather forecasting.
Autonomous Guidance Algorithm to Auto-Pilot Spacecraft in the Vicinity of Primitive Celestial BodiesTBMG-224097/1/2015
The dynamics in the vicinity of small bodies are highly nonlinear. Trajectory design in small-body environments requires accurate gravity and solar radiation pressure models to guarantee the satisfaction of spacecraft operational constraints such as thruster silent times, state, and control constraints. The G-PROX guidance algorithm generates fuel-optimal trajectories in the vicinity of asteroids and small bodies. The non-convexity in the control constraints is handled with the lossless convexification technique, which is a convex relaxation of the control constraints. G-PROX uses sequential convex programming and solves a convergent sequence of convex optimization problems generated via sequential linearization of both the dynamics and control bounds, synergistically combined with lossless convexification. The sequence of convex optimization problems converges to a locally optimal solution of the original nonlinear non-convex problem.
High-Energy Instrumentation for Small Satellite PlatformsTBMG-219925/1/2015
Given the increased availability of small satellite opportunities either through CubeSats or the Air Force’s University Nanosat program, and the limited availability of larger platforms, it is challenging to develop new instrumentation that not only fits within the envelope of small satellites, but also addresses the diverse science applications available in low Earth orbit (LEO). While small-platform instrumentation is limited in sensitivity, the ability to populate LEO with a fleet of instruments opens new science objectives not available with larger standalone payloads. Furthermore, coordinated observations of a variety of radiation species that either enter LEO from the Sun or heliosphere directly, or that reside within the radiation belts themselves, are necessary to fully reach closure on complex processes that govern particle acceleration and transport.
Neutron Spectrometer for Inner Radiation Belt StudiesTBMG-219915/1/2015
The Earth’s magnetosphere offers a wealth of information on particle dynamics, acceleration, and trapping. Fast neutrons, produced in the Earth’s atmosphere by the impact of galactic cosmic rays (GCRs) and solar energetic particles (SEPs), are an important but poorly measured component of the radiation environment in the inner magnetosphere. Cosmic ray albedo neutron decay (CRAND), whereby atmospheric neutrons beta-decay into protons and electrons, is a significant source of energetic protons in the inner radiation belt. Current models of the inner proton belt rely heavily on Monte Carlo simulations for the CRAND component, validated primarily by a handful of single-point balloon measurements from the 1970s.
Space Weather Database of Notifications, Knowledge, Information — DONKITBMG-220255/1/2015
SW DONKI is a comprehensive Web application for space weather forecasters, scientists, and the general space weather community. It serves as an archive for space weather activities including solar flares, coronal mass ejections (CMEs), solar energetic particles, and geomagnetic storms. An innovative feature of the system is the ability to generate, modify, and store complex linkages between space weather events — creating a comprehensive network of relationships between activities, and identifying potential cause-and-effect paradigms for each space weather event. SW DONKI also provides public access to all human-generated event analysis and notifications produced by the Space Weather Research Center (SWRC) forecasting team at CCMC (Community Coordinated Modeling Center).
One-Dimensional Solar Heat Load Simulation Model for a Parked Car2015-01-03564/14/2015
Passenger comfort and safety are major drivers in a typical automotive design and optimization cycle. Addressing thermal comfort requirements and the thermal management of the passenger cabin within a car, which involves accurate prediction of the temperature of the cabin interior space and the various aggregates that are present in a cabin, has become an area of active research. Traditionally, these have been done using experiments or detailed three-dimensional Computational Fluid Dynamics (CFD) analysis, which are both expensive and time-consuming. To alleviate this, recent approaches have been to use one-dimensional system-level simulation techniques with a goal to shorten the design cycle time and reduce costs. This paper describes the use of Modelica language to develop a one-dimensional mathematical model using Modelica language for automotive cabin thermal assessment when the car is subjected to solar heat loading. The developed model has the capability to predict the thermal response of a car cabin and its internal aggregates, such as seats, dashboards, roof, etc. for hot day solar loading conditions. A solar radiation model is established to capture the solar radiation that included movement of the sun position with time. In addition, the model included natural convection heat transfer and solid conduction effects for precise prediction of cabin aggregates temperature. The developed one-dimensional model is validated by comparing its predictions against the prediction of a high-resolution three-dimensional CFD model for a range of boundary and operating conditions. The results show an excellent agreement with CFD results with the temperatures being predicted to within ±2 K of that predicted by the CFD model.
Patil, Aniket, Radle, Manoj, Shome, Biswadip, Ramachandran, Sankar
Solar Powered Vehicle Parking Ventilation System Pre-Cooling Analysis2015-01-03674/14/2015
The cabin air temperature increases quickly and can reach 80°C when the vehicle parks in the summer sunlight which has the bad influence on the occupants entering comfort. Some luxury vehicles, like Audi A8[1], reduce the internal temperature through operating air-condition in advance or using on-board battery to drive the cabin ventilator, which requires relatively complex control system and limits the system's operating time because of energy consumption. This research adopts the solar wing as the ventilation power supply and accomplishes the cabin real-time heat rejection by achieving the steady air circulation for both inside and outside environment. First, the static thermal transfer model of the crew cabin is established. Then, on the basis of the parameters of the prototype ventilation pipe, the ventilation model for the outside circulation is built. After that, the parameters of the solar wing are determined according to the control target of the cabin internal air temperature. Besides, combination of the working conditions for both the solar wing and the ventilator are analyzed. Experiments have been conducted for verifying the static thermal transfer model and the ventilation model. The results show that the system can reduce the cabin air temperature with a maximum of 15°C, therefore, the occupant entering comfort is improved when vehicle is parking under the hot sun.
Hu, Zhiqiang, Tan, Gangfeng, Li, Zhilei, Xu, Haobo, Huang, Wenhui, Ye, Yifan
Sleeper Cab Climate Control Load Reduction for Long-Haul Truck Rest Period Idling2015-01-03514/14/2015
Annual fuel use for long-haul truck rest period idling is estimated at 667 million gallons in the United States. The U.S. Department of Energy's National Renewable Energy Laboratory's CoolCab project aims to reduce heating, ventilating, and air conditioning (HVAC) loads and resulting fuel use from rest period idling by working closely with industry to design efficient long-haul truck climate control systems while maintaining occupant comfort. Enhancing the thermal performance of cab/sleepers will enable smaller, lighter, and more cost-effective idle reduction solutions. In order for candidate idle reduction technologies to be implemented at the original equipment manufacturer and fleet level, their effectiveness must be quantified. To address this need, a number of promising candidate technologies were evaluated through experimentation and modeling to determine their effectiveness in reducing rest period HVAC loads. For this study, load reduction strategies were grouped into the focus areas of solar envelope, occupant environment, and conductive pathways. The technologies selected for a complete-cab package of technologies were “ultra-white” paint, advanced insulation, and advanced curtains. To measure the impact of these technologies, a nationally-averaged solar-weighted reflectivity long-haul truck paint color was determined and applied to the baseline test vehicle. Using the complete-cab package of technologies, electrical energy consumption for long-haul truck daytime rest period air conditioning was reduced by at least 35% for summer weather conditions in Colorado. The National Renewable Energy Laboratory's CoolCalc model was then used to extrapolate the performance of the thermal load reduction technologies nationally for 161 major U.S. cities using typical weather conditions for each location over an entire year.
Lustbader, Jason A., Kreutzer, Cory, Adelman, Steven, Yeakel, Skip, Zehme, John
The Energy Management for Solar Powered Vehicle Parking Ventilation System2015-01-01494/14/2015
In summer, when vehicle parks in direct sunlight, the closed cabin temperature would rise sharply, which affects the occupants step-in-car comfort Solar powered vehicle parking ventilation system adopts the solar energy to drive the original ventilator. Thus, the cabin temperature could be dramatically decreased and the riding comfort could be also improved. This research analyzed the modified crew cabin thermal transfer model. Then the performance of the solar powered ventilation system is analyzed and optimized combined with the power supply characteristics of the photovoltaic element. The storage and reuse of the solar power is achieved on condition that the cabin temperature could be steadily controlled. The research shows that, the internal temperature is mainly affected by the solar radiation intensity and the environment temperature. Within the environmental conditions area where the environmental temperature is set from 30°C to 45°C and the solar radiation intensity is set from 200 W/m2 to 1000 W/m2, the ventilation system without the energy management can keep the temperature inside the car higher than the highest environmental temperature by 5 to 10 degrees under about 80% of the environmental conditions. Under the condition of reaching same effect on controlling internal temperature as above, the energy management system can distribute electrical energy reasonably, making the ventilation system adapt to more than 90% of the environmental conditions. Under normal weather condition in the summer, the system works from 7 am to 5 pm, while the internal temperature is well controlled, it collects electrical energy of around 0.02KW·h. The system can collect electrical energy of about 0.1KW·h after the car with the system has driven for 2 hours under the condition that the sun radiation intensity is about 900W/m2. The saving electrical energy can effectively guarantee the system to adapt to changing environmental conditions.
Wang, Can, Tan, Gangfeng, Guo, Xuexun, Tian, Zhewen, Tian, Zhanwei, Li, Jiafan
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