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Marzwell, Neville

Publications and source records attributed to Marzwell, Neville.

14 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2009

High-Efficiency Artificial Photosynthesis Using a Novel Alkaline Membrane Cell

A new cell designed to mimic the photosynthetic processes of plants to convert carbon dioxide into carbonaceous products and oxygen at high efficiency, has an improved configuration using a polymer membrane electrolyte and an alkaline medium. This increases efficiency of the artificial photosynthetic process, achieves high conversion rates, permits the use of inexpensive catalysts, and widens the range of products generated by this type of process. The alkaline membrane electrolyte allows for the continuous generation of sodium formate without the need for any additional separation system. The electrolyte type, pH, electrocatalyst type, and cell voltage were found to have a strong effect on the efficiency of conversion of carbon dioxide to formate. Indium electrodes were found to have higher conversion efficiency compared to lead. Bicarbonate electrolyte offers higher conversion efficiency and higher rates than water solutions saturated with carbon dioxide. pH values between 8 and 9 lead to the maximum values of efficiency. The operating cell voltage of 2.5 V, or higher, ensures conversion of the carbon dioxide to formate, although the hydrogen evolution reaction begins to compete strongly with the formate production reaction at higher cell voltages. Formate is produced at indium and lead electrodes at a conversion efficiency of 48 mg of CO2/kilojoule of energy input. This efficiency is about eight times that of natural photosynthesis in green plants. The electrochemical method of artificial photosynthesis is a promising approach for the conversion, separation and sequestration of carbon dioxide for confined environments as in space habitats, and also for carbon dioxide management in the terrestrial context. The heart of the reactor is a membrane cell fabricated from an alkaline polymer electrolyte membrane and catalyst- coated electrodes. This cell is assembled and held in compression in gold-plated hardware. The cathode side of the cell is supplied with carbon dioxide-saturated water or bicarbonate solution. The anode side of the cell is supplied with sodium hydroxide solution. The solutions are circulated past the electrodes in the electrochemical cell using pumps. A regulated power supply provides the electrical energy required for the reactions. Photovoltaic cells can be used to better mimic the photosynthetic reaction. The current flowing through the electrochemical cell, and the cell voltage, are monitored during experimentation. The products of the electrochemical reduction of carbon dioxide are allowed to accumulate in the cathode reservoir. Samples of the cathode solution are withdrawn for product analysis. Oxygen is generated on the anode side and is allowed to vent out of the reservoir.

Narayan, Sri↗
NASA NTRS2008

Millimeter-Wave Wireless Power Transfer Technology for Space Applications

In this paper we present a new compact, scalable, and low cost technology for efficient receiving of power using RF waves at 94 GHz. This technology employs a highly innovative array of slot antennas that is integrated on substrate composed of gold (Au), silicon (Si), and silicon dioxide (SiO2) layers. The length of the slots and spacing between them are optimized for a highly efficient beam through a 3-D electromagnetic simulation process. Antenna simulation results shows a good beam profile with very low side lobe levels and better than 93% antenna efficiency.

Slot Antenna↗
NASA NTRS2008

Microgravity, Mesh-Crawling Legged Robots

The design, fabrication, and microgravity flight-testing are part of a continuing development of palm-sized mobile robots that resemble spiders (except that they have six legs apiece, whereas a spider has eight legs). Denoted SpiderBots (see figure), they are prototypes of proposed product line of relatively inexpensive walking robots that could be deployed in large numbers to function cooperatively in construction, repair, exploration, search, and rescue activities in connection with exploration of outer space and remote planets.

Behar, Alberto↗
NASA NTRS2008

Opportunities offered by space technology to enable the next giant leap in the evolution

As humanity entering the new millennium with many of the profound challenges ever encountered in the history of mankind due to population increases faster than wealth creation, surge of ambitions by many countries to achieve better life independent of risk or their available resources and capabilities. The challenge to predict or control the evolution of world crisis is even harder because of the ease in acquiring knowledge, information, and technical capabilities by any individual or group due to the wide spread of “know-how” through the internet to all people without having to invest in technology development.

Marzwell, Neville↗
NASA NTRS2005

Enabling Interoperable Space Robots With the Joint Technical Architecture for Robotic Systems (JTARS)

Robots that operate independently of one another will not be adequate to accomplish the future exploration tasks of long-distance autonomous navigation, habitat construction, resource discovery, and material handling. Such activities will require that systems widely share information, plan and divide complex tasks, share common resources, and physically cooperate to manipulate objects. Recognizing the need for interoperable robots to accomplish the new exploration initiative, NASA s Office of Exploration Systems Research & Technology recently funded the development of the Joint Technical Architecture for Robotic Systems (JTARS). JTARS charter is to identify the interface standards necessary to achieve interoperability among space robots. A JTARS working group (JTARS-WG) has been established comprising recognized leaders in the field of space robotics including representatives from seven NASA centers along with academia and private industry. The working group s early accomplishments include addressing key issues required for interoperability, defining which systems are within the project s scope, and framing the JTARS manuals around classes of robotic systems.

Bradley, Arthur↗
NASA NTRS2003

Strategic Research Directions in Microgravity Materials Science

The next challenge of space exploration is the development of the capabilities for long-term missions beyond low earth orbit. NASA s scientific advisory groups and internal mission studies have identified several fundamental issues which require substantial advancements in new technology if these goals are to be accomplished. Crews must be protected from the severe radiation environment beyond the earth s magnetic field. Chemical propulsion must be replaced by systems that require less mass and are more efficient. The overall launch complement must be reduced by developing repair and fabrication techniques which utilize or recycle available materials.

Clinton, Raymond G.↗
NASA NTRS2001

Residue detection for real-time removal of paint from metallic surfaces

Paint stripping from large steel ships and other metallic surfaces is a major issue in the maintenance and refurbishing of structures, and environmental concerns are greatly limiting the possible options. As a result, waterjet with water recycling has become the leading form of paint stripping and robotic manipulators with scanning bridges were constructed by various manufacturers to address this need. The application of such scanning bridges is slow and their access is constrained by the complex shape of the ship hull and various features on the surface. To overcome these limitations, a robotic system that is called Ultrastrip (UltraStrip Systems, Inc., Stuart, FL) is developed. This system uses magnetic wheels to attach the stripper to the structure and travel on it while performing paint stripping. To assure efficient paint stripping feedback data is required to control the travel speed by monitoring the paint thickness before and during the stripping process. Efforts at JPL are currently underway to develop the required feedback capability to assure effective paint stripping. Various possible sensors were considered and issues that can affect the sensitivity, reliability and applicability of the sensors are being investigated with emphasis on measuring the initial conditions of the paint. Issues that affect the sensory data in dynamic conditions are addressed while providing real-time real feedback for the control of the paint stripper speed of travel.

NDT↗
NASA NTRS1997

Optical Microactuation in Piezoceramics

Optically/electrically operable flexible film microactuators that can offer upto two orders higher efficiency of photonic to mechanical conversion compared to ceramic actuators are conceptualised.

Piezoceramics↗
NASA NTRS1996

Holographic Imaging In Dense Artificial Fog

Artificial fog serves as volume-projection medium for display of three-dimensional image. Projection technique enables display of images for variety of purposes, possibly including entertainment, indoor and outdoor advertising, medical diagnostics and image representations for surgical procedures, and education.

Liu, Hua-Kuang↗
NASA NTRS1996

Laser-Scan Ultrasonic/Thermographic Inspection System

Laser ultrasonic/thermographic inspection system is conceptual instrument used in nondestructive inspection of large areas of structures for subsurface defects. For example, operated in field to examine aircraft and pressure vessels for hidden cracks. System would not require contact with inspected structure or use of ultrasonic-coupling medium. Instrument obtains data in ultrasonic and thermographic C-scans over structural surfaces with contours characterized by surface normal vectors varying by angles as large as 45 degrees.

Bar-Cohen, Yoseph↗
NASA NTRS1995

Laser Opto-Electronic Correlator for Robotic Vision Automated Pattern Recognition

A compact laser opto-electronic correlator for pattern recognition has been designed, fabricated, and tested. Specifically it is a translation sensitivity adjustable compact optical correlator (TSACOC) utilizing convergent laser beams for the holographic filter. Its properties and performance, including the location of the correlation peak and the effects of lateral and longitudinal displacements for both filters and input images, are systematically analyzed based on the nonparaxial approximation for the reference beam. The theoretical analyses have been verified in experiments. In applying the TSACOC to important practical problems including fingerprint identification, we have found that the tolerance of the system to the input lateral displacement can be conveniently increased by changing a geometric factor of the system. The system can be compactly packaged using the miniature laser diode sources and can be used in space by the National Aeronautics and Space Administration (NASA) and ground commercial applications which include robotic vision, and industrial inspection of automated quality control operations. The personnel of Standard International will work closely with the Jet Propulsion Laboratory (JPL) to transfer the technology to the commercial market. Prototype systems will be fabricated to test the market and perfect the product. Large production will follow after successful results are achieved.

Laser Opto-Electronic↗
NASA NTRS1990

Assessment of the A&R Technology associated with the use of supervised autonomy for on-orbit satellite servicing

The Satellite Servicer Flight Demonstration Program is NASA's first definitive attempt at addressing the problems associated with the supervised autonomous servicing of satellites in orbit. NASA has completed a study of its on-orbit requirements for the next decade. Utilizing the results of this study, the necessary key servicing functions, which require on-orbit demonstration before a program would commit to servicing capability, were determined. These capabilities are: (1) autonomous rendezvous and docking; (2) supervised autonomous orbital replacement unit exchange; and (3) supervised autonomous fluid transfer. A satellite servicer system plan to conduct a series of on-orbit flight demonstrations of these capabilities utilizing the Orbital Maneuvering Vehicle, elements of the Flight Telerobotic Servicer and other applicable hardware has been developed. This paper surveys the A&R technologies that must be matured from the laboratory to flight status prior to conducting these on-orbit flight demonstrations.

Levin, George M.↗