Results for “Reaction center” — Page 13

NASA NTRS1990

Prebiotic synthesis of histidyl-histidine

Histidyl-histidine (His-His) has been synthesized in a yield of up to 14.4% under plausible prebiotic conditions using histidine (His), cyanamide, and 4-amino-5-imidazole carboxamide. A trace amount of His trimer was also detected. Because the imidazole group of His is involved in a number of important enzymatic reactions, and His-His has been shown to catalyze the prebiotic synthesis of glycyl-glycine, we expect this work will stimulate further studies on the catalytic activities of simple His-containing peptides in prebiotic reactions.

NASA Discipline Exobiology↗

NASA NTRS2026

Prototype Demonstration of Solar-Carbothermal System to Extract Oxygen From Regolith

The Carbothermal Reduction Demonstration (CaRD) project was an effort to develop a prototype system to demonstrate the extraction of oxygen from simulated lunar regolith using concentrated solar energy and a carbothermal reaction. The prototype consisted of a deployable solar concentrator capable of tracking the sun, carbothermal reactor, fluid system, gas analysis, and a solar concentrator control system consisting of avionics and software. These subsystems were developed by multiple NASA centers and a private industry partner, Sierra Space. The various teams worked together to define requirements and interfaces to successfully assemble the complex system and demonstrate an integrated solar carbothermal process. The solar concentrator developed at Glenn Research Center (GRC) was designed to be stowed for a launch environment then deployed on the lunar surface. It utilized a crossed dragone configuration of composite mirrors to direct horizontal sunlight onto a target 90° from the incoming sunlight. The key performance parameters for the solar concentrator were efficiency and power density. The carbothermal reactor was developed by Sierra Space through a separate project called the Carbothermal Oxygen Production Reactor (COPR) where it successfully demonstrated a fully automated process in a thermal vacuum environment [1]. The fluid system needed for the carbothermal reaction was also developed by Sierra Space and successfully demonstrated in the same thermal vacuum test. The gas analysis system was developed at Kennedy Space Center (KSC) and was required to determine the amount of oxygen extracted during each test. The gas analysis system was based on the Mass Spectrometer Observing Lunar Operations (MSOLO) instrument. Avionics and software for the CaRD prototype were also developed at KSC and based on experience with MSOLO avionics and software. The control system was designed to stow, deploy, track the sun, and perform beam alignment of the concentrated light. The prototype subsystems were integrated and tested at Johnson Space Center’s (JSC) Energy Systems Test Area. A heliostat was used to direct sunlight toward the prototype in a way that is representative of the sunlight conditions at the south pole of the Moon. When concentrated sunlight was focused on simulated lunar regolith within the reactor, the gas analysis team confirmed the presence of carbon monoxide gas, which confirmed that a solar carbothermal reaction took place. The key performance parameter for the integrated prototype was grams of oxygen extracted per kilowatt hour of energy arriving at the concentrator primary mirror. The prototype design successfully demonstrated end-to-end capability and further steps to achieve a flight capable system have been defined. With lunar data, engineers would be able to design a scaled-up system capable of extracting oxygen from regolith at useful quantities for crew life support and rocket propellant. On the long term, this method of In-Situ Resource Utilization could be used to drastically reduce the cost and risk of a sustained human presence on the Moon by reducing the amount of oxygen that would have to be delivered.

Koorosh R Araghi↗

NASA NTRS1990

Design of a prototype secondary mirror assembly for the Space Infrared Telescope Facility

The design of a liquid helium temperature prototype secondary mirror assembly (PSMA) under development for the NASA Space Infrared Telescope Facility (SIRTF) program is described. The SIRTF assembly must operate below 4 K and provide the functions of highly precise two-axis periodic tilting ('chopping') in addition to the conventional functions of focus and collimation adjustment. The PSMA design employs a fused quartz mirror kinematically attached at its center to an aluminum cruciform. The mirror/cruciform assembly is driven in tilt about its combined center of mass using an aluminum flexure pivot of unique design and a four-actuator control system with feedback provided by pairs of differential position sensors. The voice coil actuators are mounted on a second flexure-pivoted mass to enhance servosystem stability and isolate the telescope from vibration-induced disturbances. The mirror/cruciform and reaction mass are attached to opposite sides of an aluminum mounting plate whose position relative to the outer housing is controlled by a six-degree-of-freedom focus and centering mechanism using pivoted actuation levers driven by lead screw/harmonic drive/stepper motor assemblies.

Stier, Mark T.↗

NASA NTRS2003

Review of the High Performance Antiproton Trap (HiPAT) Experiment at the Marshall Space Flight Center

The significant energy density of matter-antimatter annihilation is attractive to the designers of future space propulsion systems, with the potential to offer a highly compact source of power. Many propulsion concepts exist that could take advantage of matter-antimatter reactions, and current antiproton production rates are sufficient to support basic proof-of-principle evaluation of technology associated with antimatter- derived propulsion. One enabling technology for such experiments is portable storage of low energy antiprotons, allowing antiprotons to be trapped, stored, and transported for use at an experimental facility. To address this need, the Marshall Space Flight Center's Propulsion Research Center is developing a storage system referred to as the High Performance Antiproton Trap (HiPAT) with a design goal of containing 10(exp 12) particles for up to 18 days. The HiPAT makes use of an electromagnetic system (Penning- Malmberg design) consisting of a 4 Telsa superconductor, high voltage electrode structure, radio frequency (RF) network, and ultra high vacuum system. To evaluate the system normal matter sources (both electron guns and ion sources) are used to generate charged particles. The electron beams ionize gas within the trapping region producing ions in situ, whereas the ion sources produce the particles external to the trapping region and required dynamic capture. A wide range of experiments has been performed examining factors such as ion storage lifetimes, effect of RF energy on storage lifetime, and ability to routinely perform dynamic ion capture. Current efforts have been focused on improving the FW rotating wall system to permit longer storage times and non-destructive diagnostics of stored ions. Typical particle detection is performed by extracting trapped ions from HiPAT and destructively colliding them with a micro-channel plate detector (providing number and energy information). This improved RF system has been used to detect various plasma modes for both electron and ion plasmas in the two traps at MSFC, including axial, cyclotron, and diocotron modes. New diagnostics are also being added to HiPAT to measure the axial density distribution of the trapped cloud to match measured RF plasma modes to plasma conditions.

Pearson, J. B.↗

NASA NTRS2001

Research to Significantly Enhance Composite Survivability at 550 F in Oxidative Environments

Prairie View A&M University using the NASA FAR grant has embarked on several paths to accomplish the initial goals of: (1) synthesizing three ring aromatic diamines to be used as monomers in the synthesis of polyamide resins; and (2) study hydrothermal aging behaviors and glass transition changes of composites synthesized at NASA Glenn Research Center. In establishing the synthesis of the three ring aromatic diamine, it has become necessary to conduct preliminary synthesis to include the nitration of diphenylmethane. The concentration and temperature were altered to assess the effect of purity of isomeric product distribution in such electrophilic aromatic substitution reaction. Products were analyzed using H and C-NMR, Thin Layer Chromatography, High Pressure Liquid Chromatography and GC-Mass Spectrometry (in progress). Results indicate that by varying the concentration of the reaction, a mixture of products can be obtained. Other electrophilic aromatic substitution reactions are also in progress such as Friedel-Craft acylation reaction using diphenylmethane with 4-nitrobenzoyl chloride to afford other diamine products. Furthermore, PVAMU has nearly completed the hydrothermal studies to assess the oxidative stability of DSP443B and DSP442A panels formulated at NASA Glenn Research Center.

Byrd, Jim↗

NASA NTRS1991

Evaluation of telerobotic systems using an instrumented task board

An instrumented task board was developed at NASA Marshall Space Flight Center (MSFC). An overview of the task board design, and current development status is presented. The task board was originally developed to evaluate operator performance using the Protoflight Manipulator Arm (PFMA) at MSFC. The task board evaluates tasks for Orbital Replacement Unit (ORU), fluid connect and transfers, electrical connect/disconnect, bolt running, and other basic tasks. The instrumented task board measures the 3-D forces and torques placed on the board, determines the robot arm's 3-D position relative to the task board using IR optics, and provides the information in real-time. The PFMA joint input signals can also be measured from a breakout box to evaluate the sensitivity or response of the arm operation to control commands. The data processing system provides the capability for post processing of time-history graphics and plots of the PFMA positions, the operator's actions, and the PFMA servo reactions in addition to real-time force/torque data presentation. The instrumented task board's most promising use is developing benchmarks for NASA centers for comparison and evaluation of telerobotic performance.

Carroll, John D.↗

NASA NTRS1992

On the transmission of partial information: inferences from movement-related brain potentials

Results are reported from a new paradigm that uses movement-related brain potentials to detect response preparation based on partial information. The paradigm uses a hybrid choice-reaction go/nogo procedure in which decisions about response hand and whether to respond are based on separate stimulus attributes. A lateral asymmetry in the movement-related brain potential was found on nogo trials without overt movement. The direction of this asymmetry depended primarily on the signaled response hand rather than on properties of the stimulus. When the asymmetry first appeared was influenced by the time required to select the signaled hand, and when it began to differ on go and nogo trials was influenced by the time to decide whether to respond. These findings indicate that both stimulus attributes were processed in parallel and that the asymmetry reflected preparation of the response hand that began before the go/nogo decision was completed.

NASA Discipline Space Human Factors↗

NASA NTRS1979

Volume-pumped nuclear lasers

A summary is given to experimental results on volume-pumped nuclear lasers obtained at the Langley Research Center. The first volume-pumped nuclear laser was achieved in 1976 using the He-3(n, p)H-3 reaction. Since that time laser output has increased by more than a factor of 1000 (from mW to W). Lasing has been demonstrated in He-3-Ar (1.27 and 1.79 micron), He-3-Xe (2.027, 3.5, and 3.65 microns), He-3-Kr (2.19 and 2.52 microns), and He-3-Cl (1.587 micron). Pressures of the lasing mixture range from 300 torr to 4 atm with a peak power output of 26 W were achieved in a He-3-Ar mixture with a multiple-pass laser configuration.

Hohl, F.↗

NASA NTRS1993

Ceramic matrix composites properties/microstresses with complete and partial interphase bond

A multilevel substructuring technique which includes a unique fiber substructuring concept is used for the analysis of continuous fiber reinforced ceramic matrix composites. This technique has four levels of substructuring--from laminate to ply, to supply, and then to fiber. A stand-alone computer code CEMCAN (Ceramic Matrix Composites Analyzer), incorporating this technique and specifically for the simulation of ceramic matrix composites behavior, is currently under development at NASA Lewis Research Center in Cleveland, Ohio. The thermal and mechanical properties, along with the microstresses, for a SiC/RBSN (silicon carbide fiber and reaction bonded silicon nitride matrix) composite at different fiber volume ratios and varying degrees of interfacial bond around the fiber circumference are computed. Values predicted by CEMCAN computer code are shown to bound the experimentally measured values. Results also show that transverse tensile strength test can be a sensitive test method to assess interfacial conditions.

Mital, Subodh K.↗

NASA NTRS2002

Nine-analyte detection using an array-based biosensor

A fluorescence-based multianalyte immunosensor has been developed for simultaneous analysis of multiple samples. While the standard 6 x 6 format of the array sensor has been used to analyze six samples for six different analytes, this same format has the potential to allow a single sample to be tested for 36 different agents. The method described herein demonstrates proof of principle that the number of analytes detectable using a single array can be increased simply by using complementary mixtures of capture and tracer antibodies. Mixtures were optimized to allow detection of closely related analytes without significant cross-reactivity. Following this facile modification of patterning and assay procedures, the following nine targets could be detected in a single 3 x 3 array: Staphylococcal enterotoxin B, ricin, cholera toxin, Bacillus anthracis Sterne, Bacillus globigii, Francisella tularensis LVS, Yersiniapestis F1 antigen, MS2 coliphage, and Salmonella typhimurium. This work maximizes the efficiency and utility of the described array technology, increasing only reagent usage and cost; production and fabrication costs are not affected.

NASA Discipline Life Sciences Technologies↗

NASA NTRS1992

Directed molecular evolution

No abstract available

Non-NASA Center↗

NASA NTRS2012

Investigation of Supercritical Water Phenomena for Space and Extraterrestrial Application

The cost of carrying or resupplying life support resources for long duration manned space exploration missions such as a mission to Mars is prohibitive and requires the development of suitable recycling technologies. Supercritical Water Oxidation (SCWO) has been identified as an attractive candidate for these extended missions because (i) pre-drying of wet waste streams is not required, (ii) product streams are relatively benign, microbially inert, and easily reclaimed, (iii) waste conversion is complete and relatively fast, and (iv) with proper design and operation, reactions can be self-sustaining. Initial work in this area at NASA was carried out at the Ames Research Center in the 1990 s with a focus on understanding the linkages between feed stock preparation (i.e., particle size and distribution) of cellulosic based waste streams and destruction rates under a range of operating temperatures and pressures. More recently, work in SCWO research for space and extra-terrestrial application has been performed at NASA s Glenn Research Center where various investigations, with a particular focus in the gravitational effects on the thermo-physical processes occurring in the bulk medium, have been pursued. In 2010 a collaborative NASA/CNES (the French Space Agency) experiment on the critical transition of pure water was conducted in the long duration microgravity environment on the International Space Station (ISS). A follow-on experiment, to study the precipitation of salt in sub-critical, trans-critical and supercritical water is scheduled to be conducted on the ISS in 2013. This paper provides a brief history of NASA s earlier work in SCWO, discusses the potential for application of SCWO technology in extended space and extraterrestrial missions, describes related research conducted on the ISS, and provides a list of future research activities to advance this technology in both terrestrial and extra-terrestrial applications.

Hicks, Michael C.↗

NASA NTRS2001

Inductive Measurement of Plasma Jet Electrical Conductivity (MSFC Center Director's discretionary Fund)

Measurement of plasma jet electrical conductivity has utility in the development of explosively driven magnetohydrodynamic (MHD) energy converters as well as magnetic flux compression reaction chambers for nuclear/chemical pulse propulsion and power. Within these types of reactors, the physical parameter of critical importance to underlying MHD processes is the magnetic Reynolds number, the value of which depends upon the product of plasma electrical conductivity and velocity. Therefore, a thorough understanding of MHD phenomena at high magnetic Reynolds number is essential, and methods are needed for the accurate and reliable measurement of electrical conductivity in high-speed plasma jets. It is well known that direct measurements using electrodes suffer from large surface resistance, and an electrodeless technique is desired. To address this need, an inductive probing scheme, originally developed for shock tube studies, has been adapted. In this method, the perturbation of an applied magnetic field by a plasma jet induces a voltage in a search coil, which, in turn, can be used to infer electrical conductivity through the inversion of a Fredholm integral equation of the first kind. A 1-in.-diameter probe using a light-gas gun. Exploratory laboratory experiments were carried out using plasma jets expelled from 15-g shaped charges. Measured conductivities were in the range of 4 kS/m for unseeded octol charges and 26 kS/m for seeded octol charges containing 2-percent potassium carbonate by mass.

Turner, M. W.↗

NASA NTRSDate not supplied

Flight Deck Design of a Hybrid Turbine/Electric Passenger Aircraft

NASA is exploring the development of a 180-passenger subsonic single engine aft turbine aircraft, The aft turbine provides electric power in a hybrid design to wing mounted electric engines, creating a highly efficient, high-bypass-ratio fan equivalent. The SUbsonic Single Aft eNgine (SUSAN) aircraft is being developed as a sustainable subsonic regional aircraft that seeks to reduce emission levels by 50% in the next few decades. Pilot-in-the-loop studies were conducted at the NASA Langley Research Center in Hampton, Virginia, to explore the flight deck design for the hybrid electric aircraft. Following modern trends in commercial aircraft flight decks with full time augmented controls and a quiet and dark philosophy, single throttle and simplified engine displays were developed for the SUSAN aircraft. The aircraft includes a single aft mounted turbine engine and 16 wing mounted electric fans. The final design was developed from feedback received during an earlier pilot-in-the-loop study where one, two, and three throttles were tested in standard airline operations, including various failures of the turbine and electric engines. Current flight deck designs normally provide control inceptors for each propulsion engine and an engine display for all primary aircraft engine parameters. With full time augmentation expected, a single throttle control with autothrottle always engaged, even during failures, is desired. Augmentation of flight controls using distributed thrust also requires full time control of the electric engines using automation. Additionally, electric engine thrust is augmented during climb based on battery state of charge. Thrust augmentation changes faster than human reaction time and therefore requires full-time automation. A pilot-in-the-loop study was conducted at the NASA Langley Research Center in Hampton, Virginia, to test the final design of the single throttle with simplified engine displays. Fourteen airline pilots evaluated the single throttle and engine display concept. Electric engine failures included one, four symmetric, and eight non-symmetric electric engine failures. The turbine engine was evaluated for complete and partial failure during critical phases of flight to include takeoff as well as enroute. Unexpected go-arounds increase workload and require significant throttle manipulation. Go-arounds were included to ensure the single throttle was usable for all phases of flight. Failures during takeoff required a return to the departure field and failures enroute required a diversion except for one and four electric engine failures as these failures did not affect aircraft flyability or range. There are currently no Part 25 aircraft certified with hybrid systems or electric engines with batteries as emergency propulsion. For turbine engine failures in the SUSAN aircraft design, range is limited to 30 minutes at full power. Battery state of charge and battery health displays were developed and tested for usability and to determine how well they supported pilot decisions for alternate airports during emergency diversions. Novel displays using shape and color were developed to provide immediate feedback when state of charge became critical. This paper details the pilot study including pilot feedback supporting the potential for increased automation and a single throttle control. Detailed recommendations are provided for a novel single throttle control and additional pilot controls to support selection of engines during start, shutdown, and engine troubleshooting procedures. This design deviates significantly from current practice of providing throttles for each propulsion engine. Engine display recommendations are provided based on pilot feedback during a guided post-evaluation interview. Battery state of charge and battery health display recommendations were collected from all airline crews. The simplified engine displays design was rated excellent as measured with a usability scale. Quantitative metrics include airspeed tracking, time to complete checklists, time to make diversion decisions and the quality of the diversion decision. Recommendations for future studies are documented with supporting research and current observations about upcoming flight deck certifications.

autothrottle↗

NASA NTRSDate not supplied

Flight Deck Design of a Hybrid Turbine/Electric Passenger Aircraft

NASA is exploring the development of a 180-passenger subsonic single engine aft turbine aircraft, The aft turbine provides electric power in a hybrid design to wing mounted electric engines, creating a highly efficient, high-bypass-ratio fan equivalent. The SUbsonic Single Aft eNgine (SUSAN) aircraft is being developed as a sustainable subsonic regional aircraft that seeks to reduce emission levels by 50% in the next few decades. Pilot-in-the-loop studies were conducted at the NASA Langley Research Center in Hampton, Virginia, to explore the flight deck design for the hybrid electric aircraft. Following modern trends in commercial aircraft flight decks with full time augmented controls and a quiet and dark philosophy, single throttle and simplified engine displays were developed for the SUSAN aircraft. The aircraft includes a single aft mounted turbine engine and 16 wing mounted electric fans. The final design was developed from feedback received during an earlier pilot-in-the-loop study where one, two, and three throttles were tested in standard airline operations, including various failures of the turbine and electric engines. Current flight deck designs normally provide control inceptors for each propulsion engine and an engine display for all primary aircraft engine parameters. With full time augmentation expected, a single throttle control with autothrottle always engaged, even during failures, is desired. Augmentation of flight controls using distributed thrust also requires full time control of the electric engines using automation. Additionally, electric engine thrust is augmented during climb based on battery state of charge. Thrust augmentation changes faster than human reaction time and therefore requires full-time automation. A pilot-in-the-loop study was conducted at the NASA Langley Research Center in Hampton, Virginia, to test the final design of the single throttle with simplified engine displays. Fourteen airline pilots evaluated the single throttle and engine display concept. Electric engine failures included one, four symmetric, and eight non-symmetric electric engine failures. The turbine engine was evaluated for complete and partial failure during critical phases of flight to include takeoff as well as enroute. Unexpected go-arounds increase workload and require significant throttle manipulation. Go-arounds were included to ensure the single throttle was usable for all phases of flight. Failures during takeoff required a return to the departure field and failures enroute required a diversion except for one and four electric engine failures as these failures did not affect aircraft flyability or range. There are currently no Part 25 aircraft certified with hybrid systems or electric engines with batteries as emergency propulsion. For turbine engine failures in the SUSAN aircraft design, range is limited to 30 minutes at full power. Battery state of charge and battery health displays were developed and tested for usability and to determine how well they supported pilot decisions for alternate airports during emergency diversions. Novel displays using shape and color were developed to provide immediate feedback when state of charge became critical. This paper details the pilot study including pilot feedback supporting the potential for increased automation and a single throttle control. Detailed recommendations are provided for a novel single throttle control and additional pilot controls to support selection of engines during start, shutdown, and engine troubleshooting procedures. This design deviates significantly from current practice of providing throttles for each propulsion engine. Engine display recommendations are provided based on pilot feedback during a guided post-evaluation interview. Battery state of charge and battery health display recommendations were collected from all airline crews. The simplified engine displays design was rated excellent as measured with a usability scale. Quantitative metrics include airspeed tracking, time to complete checklists, time to make diversion decisions and the quality of the diversion decision. Recommendations for future studies are documented with supporting research and current observations about upcoming flight deck certifications.

autothrottle↗

NASA NTRS1990

LaRC-developed catalysts for CO2 lasers

Pulsed CO2 lasers have many remote sensing applications from space, airborne, and ground platforms. The NASA Laser Atmospheric Wind Sounder (LAWS) system will be designed to measure wind velocities from polar earth orbit for a period of up to three years. Accordingly, this and other applications require a closed-cycle pulsed CO2 laser which necessitates the use of an efficient CO-O2 recombination catalyst for these dissociation products which otherwise would degrade the laser operation. The required catalyst must not only operate at low temperatures but also must operate efficiently for long time periods. The research effort at NASA LaRC has centered around development and testing of CO oxidation catalysts for closed-cycle, pulsed, common and rare-isotope CO2 lasers. Researchers examined available commercial catalysts both in a laser and under simulated closed-cycle laser conditions with efforts aimed toward a thorough understanding of the fundamental catalytic reaction. These data were used to design and synthesize new catalyst compositions to better meet the catalyst requirements for closed-cycle pulsed CO2 lasers. Syntheses and test results for catalysts developed at Langley Research Center which have significantly better long-term decay characteristics than previously available catalysts and at the same time operate quite well under lower temperature conditions are discussed.

Upchurch, Billy T.↗

NASA NTRS2001

Kinetics of antigen binding to arrays of antibodies in different sized spots

A fluorescence-based array biosensor has been developed which can measure the binding kinetics of an antigen to an immobilized antibody in real time. A patterned array of antibodies immobilized on the surface of a planar waveguide was used to capture a Cy5-labeled antigen present in a solution that was continuously flowed over the surface. The CCD image of the waveguide was monitored continuously for 25 min. The resulting exponential rise in fluorescence signal was determined by image analysis software and fitted to a reaction-limited kinetics model, giving a kf of 3.6 x 10(5) M(-1) s(-1). Different spot sizes were then patterned on the surface of the waveguide using either a PDMS flow cell or laser exposure, producing width sizes ranging from 80 to 1145 microm. It was demonstrated that under flow conditions, the reduction of spot size did not alter the association rate of the antigen with immobilized antibody; however, as the spot width decreased to < 200 nm, the signal intensity also decreased.

Non-NASA Center↗

NASA NTRS1989

Arc jet diagnostics tests

Two objectives were addressed during a 10 week 1988 NASA/ASEE summer faculty fellowship at the Johnson Space Center Atmospheric Reentry Materials Structures Evaluation Facility (ARMSEF). These objectives were the evaluation of mass spectrometry for the measurement of atomic and molecular species in an arc jet environment, and the determination of atomic recombination coefficients for reaction cured glass (RCG) coated high temperature surface insulation (HRSI) materials subjected to simulated reentry conditions. Evaluation of mass spectrometry for the measurement of atomic and molecular species provided some of the first measurements of point compositions in arc jet tunnel environments. A major objective of this project centered around the sampling residence time. A three staged vacuum sampling system pulled the molecules and atoms from the arc jet to a quadrupole ionization mass spectrometer in 400 milliseconds. Conditions investigated included a composition survey across the nozzle exit at 3 cm z-distance from the nozzle exit for 3 different currents. Also, a point composition survey was taken around a shock created by the presence of a blunt body.

Willey, Ronald J.↗