Engineering topics

Jordan, Kevin

Publications and source records attributed to Jordan, Kevin.

14 records

NASA NTRS2015

Efficient Boron-Carbon-Nitrogen Nanotube Formation Via Combined Laser-Gas Flow Levitation

A process for producing boron nitride nanotubes and/or boron-carbon-nitrogen nanotubes of the general formula BxCyNz. The process utilizes a combination of laser light and nitrogen gas flow to support a boron ball target during heating of the boron ball target and production of a boron vapor plume which reacts with nitrogen or nitrogen and carbon to produce boron nitride nanotubes and/or boron-carbon-nitrogen nanotubes of the general formula BxCyNz.

Whitney, R. Roy↗

NASA NTRS2014

Efficient Boron Nitride Nanotube Formation via Combined Laser-Gas Flow Levitation

A process for producing boron nitride nanotubes and/or boron-carbon-nitrogen nanotubes of the general formula B(sub x)C(sub y)N(sub z) The process utilizes a combination of laser light and nitrogen gas flow to support a boron ball target during heating of the boron ball target and production of a boron vapor plume which reacts with nitrogen or nitrogen and carbon to produce boron nitride nanotubes and/or boron-carbon-nitrogen nanotubes of the general formula B(sub x)C(sub y)N(sub z).

Whitney, R. Roy↗

NASA NTRS2014

Unmanned Aircraft System (UAS) Delegation of Separation in NextGen Airspace

The purpose of this study was to determine the feasibility of unmanned aircraft systems (UAS) performing delegated separation in the national airspace system (NAS). Delegated separation is the transfer of responsibility for maintaining separation between aircraft or vehicles from air navigation service providers to the relevant pilot or flight operator. The effects of delegated separation and traffic display information level were collected through performance, workload, and situation awareness measures. The results of this study show benefits related to the use of conflict detection alerts being shown on the UAS operator's cockpit situation display (CSD), and to the use of full delegation. Overall, changing the level of separation responsibility and adding conflict detection alerts on the CSD was not found to have an adverse effect on performance as shown by the low amounts of losses of separation. The use of conflict detection alerts on the CSD and full delegation responsibilities given to the UAS operator were found to create significantly reduced workload, significantly increased situation awareness and significantly easier communications between the UAS operator and air traffic controller without significantly increasing the amount of losses of separation.

NextGen↗

NASA NTRS2012

Boron Nitride Nanotubes

Boron nitride nanotubes are prepared by a process which includes: (a) creating a source of boron vapor; (b) mixing the boron vapor with nitrogen gas so that a mixture of boron vapor and nitrogen gas is present at a nucleation site, which is a surface, the nitrogen gas being provided at a pressure elevated above atmospheric, e.g., from greater than about 2 atmospheres up to about 250 atmospheres; and (c) harvesting boron nitride nanotubes, which are formed at the nucleation site.

Smith, Michael W.↗

NASA NTRS2008

Multifunctional Nanotube Polymer Nanocomposites for Aerospace Applications: Adhesion between SWCNT and Polymer Matrix

Multifunctional structural materials can enable a novel design space for advanced aerospace structures. A promising route to multifunctionality is the use of nanotubes possessing the desired combination of properties to enhance the characteristics of structural polymers. Recent nanotube-polymer nanocomposite studies have revealed that these materials have the potential to provide structural integrity as well as sensing and/or actuation capabilities. Judicious selection or modification of the polymer matrix to promote donor acceptor and/or dispersion interactions can improve adhesion at the interface between the nanotubes and the polymer matrix significantly. The effect of nanotube incorporation on the modulus and toughness of the polymer matrix will be presented. Very small loadings of single wall nanotubes in a polyimide matrix yield an effective sensor material that responds to strain, stress, pressure, and temperature. These materials also exhibit significant actuation in response to applied electric fields. The objective of this work is to demonstrate that physical properties of multifunctional material systems can be tailored for specific applications by controlling nanotube treatment (different types of nanotubes), concentration, and degree of alignment.

Park, Cheol↗

NASA NTRS2008

Beyond 'Inop': Logbook Communication Between Airline Mechanics and Pilots

When mechanical discrepancies occur on aircraft, effective communication between pilots and mechanics can facilitate identification of the problem. A survey of pilots and mechanics was conducted to determine how often they were able to discuss discrepancies directly and to identify factors that influenced the detail they provided about discrepancies in the aircraft logbook. Logistical factors such as short turn times between flights and crew schedules appeared to present barriers to face-to-face meetings between pilots and mechanics. Guidelines for pilot logbook entries. Pilots reported receiving significantly less training on writing logbook entries and spent significantly less time making individual entries than mechanics. Mechanics indicated greater concern about the Federal Aviation Administration reading their entries than pilots. Mechanics indicated they had little opportunity to follow up with pilots to clarify a logbook entry once pilots departed the aircraft.

Munro, Pamela A.↗

NASA NTRS2003

Sensitivity and Bias in Searches of Cockpit Display of Traffic Information Utilizing Highlighting/Lowlighting

A previous investigation showed that when bright and dim traffic symbols were mixed together on a cockpit display of traffic information, dim targets required longer search times than bright targets. The current experiment utilized Signal Detection methodology to determine the cause of this effect. Two factors were manipulated, Intensity and Mixture. The Intensity manipulation varied whether targets were bright or dim. The Mixture manipulation varied whether the brightness of all aircraft symbols was the same, or if half were bright and half dim. Participants were given 1.25 s to search a display of eight aircraft and determine whether a target was present or absent (50% of the time a target was present) and then rated their confidence in the accuracy of their decision. A Mixture by Intensity repeated-measures ANOVA on the signal detectability measure, A (a non- parametric variant of d ), revealed that targets presented at the dim intensity in the mixed condition yielded significantly lower sensitivity than either of the pure (homogenous) conditions or the bright targets in the mixed condition. There was not a significant difference in False Alarm rates between any conditions, indicating no change in decision criterion. Findings are discussed in terms of possible masking effects evoked by bright aircraft over the dim aircraft. Funding for this work was provided by the Advanced Air Transportation Technologies Project of NASA s Airspace Operation Systems Program.

Johnson, Walter W.↗

NASA NTRS2003

Development and Demonstration of a Prototype Free Flight Cockpit Display of Traffic Information

Two versions of a prototype Free Flight cockpit situational display (Basic and Enhanced) were examined in a simulation at the NASA Ames Research Center. Both displays presented a display of traffic out to a range of 120 NM, and an alert when the automation detected a substantial danger of losing separation with another aircraft. The task for the crews was to detect and resolve threats to separation posed by intruder aircraft. An Enhanced version of the display was also examined. It incorporated two additional conflict alerting levels and tools to aid in trajectory prediction and path planning. Ten crews from a major airline participated in the study. Performance analyses and pilot debriefings showed that the Enhanced display was preferred, and that minimal separation between the intruder and the ownship was larger with the Enhanced display. In addition, the additional information on the Enhanced display did not lead crews to engage in more maneuvering. Instead an opposite trend was indicated. Finally, crews using the Enhanced display responded more proactively, tending to resolve alerts earlier.

Johnson, Walter W.↗

NASA NTRS2000

Free Flight Simulation: An Initial Examination of Air-Ground Integration Issues

The concept of "free flight" is intended to emphasize more flexibility for operators in the National Airspace System (RTCA, 1995). This may include the potential for aircraft self-separation. The purpose of this simulation was to begin examining some of the communication and procedural issues associated with self-separation in an integrated air-ground environment. Participants were 10 commercial U.S. flight crews who flew the B747-400 simulator and 10 Denver ARTCC controllers who monitored traffic in an ATC simulation. A prototypic airborne alerting logic and flight deck display features were designed to allow for increased traffic and maneuvering information. Eight different scenarios representing different conflict types were developed. The effects of traffic density (high and low) and different traffic convergence angles (obtuse, acute, and right) were assessed. Conflict detection times were found to be lower for the flight crews in low density compared to high density scenarios. For the controllers, an interaction between density and convergence angle was revealed. Analyses on the controller detection times found longer detection times in the obtuse high density compared to obtuse low density, as well as the shortest detection times in the high density acute angle condition. Maneuvering and communication events are summarized, and a discussion of future research issues is provided.

Lozito, Sandra↗

NASA NTRS1999

Aerospace Human Factors

The following contains the final report on the activities related to the Cooperative Agreement between the human factors research group at NASA Ames Research Center and the Psychology Department at San Jose State University. The participating NASA Ames division has been, as the organization has changed, the Aerospace Human Factors Research Division (ASHFRD and Code FL), the Flight Management and Human Factors Research Division (Code AF), and the Human Factors Research and Technology Division (Code IH). The inclusive dates for the report are November 1, 1984 to January 31, 1999. Throughout the years, approximately 170 persons worked on the cooperative agreements in one capacity or another. The Cooperative Agreement provided for research personnel to collaborate with senior scientists in ongoing NASA ARC research. Finally, many post-MA/MS and post-doctoral personnel contributed to the projects. It is worth noting that 10 former cooperative agreement personnel were hired into civil service positions directly from the agreements.

Jordan, Kevin↗

NASA NTRS1998

Learning to Identify Airports from Photographs Versus Navigational Maps Presented at Various Orientations

We previously demonstrated: 1) initial learning of navigational maps produced discriminative reaction times (RTs) that were most rapid when the maps were seen in the same orientation as that in which they were initially learned, 2) RTs were significantly reduced with repeated representations, and 3) information learned from the map was not sufficient for all observers to recognize aerial photographs of the same airports. The present study examined the relative effectiveness of initial training on photographs versus maps.

Cohen, Malcolm M.↗

NASA NTRS1998

Evaluation of Cabin Crew Technical Knowledge

Accident and incident reports have indicated that flight attendants have numerous opportunities to provide the flight-deck crew with operational information that may prevent or essen the severity of a potential problem. Additionally, as carrier fleets transition from three person to two person flight-deck crews, the reliance upon the cabin crew for the transfer of this information may increase further. Recent research (Chute & Wiener, 1996) indicates that light attendants do not feel confident in their ability to describe mechanical parts or malfunctions of the aircraft, and the lack of flight attendant technical training has been referenced in a number of recent reports (National Transportation Safety Board, 1992; Transportation Safety Board of Canada, 1995; Chute & Wiener, 1996). The present study explored both flight attendant technical knowledge and flight attendant and dot expectations of flight attendant technical knowledge. To assess the technical knowledge if cabin crewmembers, 177 current flight attendants from two U.S. carriers voluntarily :ompleted a 13-item technical quiz. To investigate expectations of flight attendant technical knowledge, 181 pilots and a second sample of 96 flight attendants, from the same two airlines, completed surveys designed to capture each group's expectations of operational knowledge required of flight attendants. Analyses revealed several discrepancies between the present level of flight attendants.

Dunbar, Melisa G.↗

NASA NTRS1993

Head-up displays: Effect of information location on the processing of superimposed symbology

Head-up display (HUD) symbology superimposes vehicle status information onto the external terrain, providing simultaneous visual access to both sources of information. Relative to a baseline condition in which the superimposed altitude indicator was omitted, altitude maintenance was improved by the presence of the altitude indicator, and this improvement was the same magnitude regardless of the position of the altitude indicator on the screen. However, a concurrent decifit in heading maintenance was observed only when the altitude indicator was proximal to the path information. These results did not support a model of the concurrent processing deficit based on an inability to attend to multiple locations in parallel. They are consistent with previous claims that the deficit is the product of attentional limits on subjects' ability to process two separate objects (HUD symbology and terrain information) concurrently. The absence of a performance tradeoff when the HUD and the path information were less proximal is attributed to a breaking of attentional tunneling on the HUD, possibly due to eye movements.

Sanford, Beverly D.↗

NASA NTRS1989

The effects of window shape and reticle presence on performance in a vertical alignment task

This study was conducted to evaluate the effect of selected interior work-station orientational cuing upon the ability to align a target image with local vertical in the frontal plane. Angular error from gravitational vertical in an alignment task was measured for 20 observers viewing through two window shapes (square, round), two initial orientations of a computer-generated space shuttle image, and the presence or absence of a stabilized optical alignment reticle. In terms of overall accuracy, it was found that observer error was significantly smaller for the square window and reticle-present conditions than for the round window and reticle-absent conditions. Response bias data reflected an overall tendency to undershoot and greater variability of response in the round window/no reticle condition. These results suggest that environmental cuing information, such as that provided by square window frames and alignment reticles, may aid in subjective orientation and increase accuracy of response in a Space Station proximity operations alignment task.

Rosenberg, Erika L.↗