SEARCH · Engineering Papers

Results for “Occupancy Measurement”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3

All sources NASA NTRS DOE OSTI

NASA NTRS2011

Planning Image-Based Measurements in Wind Tunnels by Virtual Imaging

Virtual imaging is routinely used at NASA Ames Research Center to plan the placement of cameras and light sources for image-based measurements in production wind tunnel tests. Virtual imaging allows users to quickly and comprehensively model a given test situation, well before the test occurs, in order to verify that all optical testing requirements will be met. It allows optimization of the placement of cameras and light sources and leads to faster set-up times, thereby decreasing tunnel occupancy costs. This paper describes how virtual imaging was used to plan optical measurements for three tests in production wind tunnels at NASA Ames.

Kushner, Laura Kathryn↗

NASA NTRS1993

Baseline characteristics of different strata of astronaut corps

The Longitudinal Study of Astronaut Health (LSAH) is an epidemiological study designed to study the effects of the occupational exposures incurred by astronauts in health outcomes and changes in physiological variables. Between 1959 and 1991, 195 individuals were selected for the program. The medical standards for selection have remained essentially unchanged since the Mercury Program, but the range and stringency of these criteria have been modified. Demographic and physiological variables identified during the selection year are examined for various strata of the Astronaut Corps. Specifically, age, sex, race, education, usual occupation, military affiliation, medical history, family medical history, visual and hearing measurements, physical exam variables, and specific laboratory values are investigated. Differences are examined in astronauts for the following criteria: (1) were selected prior to 1970 (n = 73) versus those selected after 1970 (n = 122); (2) have flown multiple missions versus those who have flown less than two missions; (3) have walked in space versus all others; (4) have more than 500 hours of mission time versus all others; and (5) have gone to the Moon versus all others. Length of time served in the Astronaut Corps is examined for each of these strata.

Hamm, Peggy B.↗

NASA NTRS2001

Proceedings from the 2001 NASA Occupational Health Conference: Risk Assessment and Management in 2001

This Conference convened approximately 86 registered participants of invited guest speakers, NASA presenters, and a broad spectrum of the Occupational Health disciplines representing NASA Headquarters and all NASA Field Centers. Two days' Professional Development Courses on Exposure Assessment Strategies and Statistics and on Advanced Cardiac Life Support training and recertification preceded the Conference. With the theme, 'Risk Assessment and Management in 2001,' conferees were first provided updates from the Program Principal Center Office and the Headquarters Office. Plenary sessions elaborated on several topics: biological terrorism, OSHA recordability, Workers' Compensation issues, Federal ergonomic standards, bridging aerospace medicine and occupational health-especially in management of risk in spaceflight, and EAP operations with mission failures. A keynote address dealt with resiliency skills for 21st century workers and two NASA astronaut speakers highlighted a tour of the Johnson Space Center. During discipline specific breakout sessions, current issues in occupational health management and policy, credentialing and privileging, health risk assessment, measurement and standardization, audits, database development, prevention and rehabilitation, international travel and infection control, employee assistance, nursing process, and environmental health were presented.

Roberson, Sheri↗

NASA NTRS2003

Overview of Atmospheric Ionizing Radiation (AIR)

The SuperSonic Transport (SST) development program within the US was based at the Langley Research Center as was the Apollo radiation testing facility (Space Radiation Effects Laboratory) with associated radiation research groups. It was natural for the issues of the SST to be first recognized by this unique combination of research programs. With a re-examination of the technologies for commercial supersonic flight and the possible development of a High Speed Civil Transport (HSCT), the remaining issues of the SST required resolution. It was the progress of SST radiation exposure research program founded by T. Foelsche at the Langley Research Center and the identified remaining issues after that project over twenty-five years ago which became the launch point of the current atmospheric ionizing radiation (AIR) research project. Added emphasis to the need for reassessment of atmospheric radiation resulted from the major lowering of the recommended occupational exposure limits, the inclusion of aircrew as radiation workers, and the recognition of civil aircrew as a major source of occupational exposures. Furthermore, the work of Ferenc Hajnal of the Environmental Measurements Laboratory brought greater focus to the uncertainties in the neutron flux at high altitudes. A re-examination of the issues involved was committed at the Langley Research Center and by the National Council on Radiation Protection (NCRP). As a result of the NCRP review, a new flight package was assembled and flown during solar minimum at which time the galactic cosmic radiation is at a maximum (June 1997). The present workshop is the initial analysis of the new data from that flight. The present paper is an overview of the status of knowledge of atmospheric ionizing radiations. We will re-examine the exposures of the world population and examine the context of aircrew exposures with implications for the results of the present research. A condensed version of this report was given at the 1998 Annual Meeting of the NCRP with proceedings published in the journal of Health Physics.

Wilson, J. W.↗

NASA NTRS2022

Winter Severity Affects Occupancy of Spring- and Summer-Breeding Anurans Across the Eastern United States

Climate change is an increasingly important driver of biodiversity loss. The ectothermic nature of amphibians may make them particularly sensitive to changes in temperature and precipitation regimes, adding to declines from other threats. While active season environmental conditions can influence growth and survival, effects of variation in winter conditions on population dynamics are less well-studied. Given that extreme winter temperatures can influence amphibian survival and fitness, we expected that increased winter severity—as measured by variability in winter temperatures and snow cover—would be associated with decreased occupancy, and that populations that experience more severe winters would have the largest sensitivities and show the greatest declines.

climate↗

NASA NTRS1974

The use of objective measurements in the evaluation of therapy programs

The importance of objective measurements is discussed as a means of assessing the efficacy of physical and occupational therapy programs applied to patients recovering from neurological diseases. Considered are three primary categories of neurologically injured patients: patients with hemiplegia, patients with spinal cord injuries, and the heterogeneous group of cerebral palsy patients.

Chaplin, H.↗

NASA NTRS1992

Reduced mobility and PPC in In(.20)Ga(.80)As / Al(.23)Ga(.77)As HEMT structure

Transport properties of a pseudomorphic In(.20)Ga(.80)As/Al(.23)Ga(.77)As High Electron Mobility Transistor (HEMT) structure were measured by Hall and SdH techniques. Two samples of identical structures but with different doping levels were compared. Low temperature mobility measurements as a function of concentration coincides with the onset of second subband occupancy, indicating that the decrease in mobility is due to intersubband scattering. In spite of the low Al content (23 percent), large persistent photoconductivity (PPC) was observed in the highly doped sample only, showing a direct correlation between the PPC and doping concentration of the barrier layer.

Schacham, S. E.↗

NASA NTRS1993

Respiratory Protection Program medical clearance for respirator use

Background on occupational exposure to various inhalents is discussed including on-site hazard control measures, procedures, physiological effects, and interpretation of results for the medical clearance of employee for use of personal respiratory protection devices. The purpose of the Respiratory Protection Program at LeRC is outlined, and the specifics of the Medical Surveillance Program for Respiratory Protection at LeRC are discussed.

Source record↗

NASA NTRS1984

Analysis of a transport fuselage section drop test

Transport fuselage section drop tests provided useful information about the crash behavior of metal aircraft in preparation for a full-scale Boeing 720 controlled impact demonstration (CID). The fuselage sections have also provided an operational test environment for the data acquisition system designed for the CID test, and data for analysis and correlation with the DYCAST nonlinear finite-element program. The correlation of the DYCAST section model predictions was quite good for the total fuselage crushing deflection (22 to 24 inches predicted versus 24 to 26 inches measured), floor deformation, and accelerations for the floor and fuselage. The DYCAST seat and occupant model was adequate to approximate dynamic loading to the floor, but a more sophisticated model would be required for good correlation with dummy accelerations. Although a full-section model using only finite elements for the subfloor was desirable, constraints of time and computer resources limited the finite-element subfloor model to a two-frame model. Results from the two-frame model indicate that DYCAST can provide excellent correlation with experimental crash behavior of fuselage structure with a minimum of empirical force-deflection data representing structure in the analytical model.

E. L. Fasanella↗

NASA NTRS2003

Decay Properties of K-Vacancy States in Fe X-Fe XVII

We report extensive calculations of the decay properties of fine-structure K-vacancy levels in Fe X-Fe XVII. A large set of level energies, wavelengths, radiative and Auger rates, and fluorescence yields has been computed using three different standard atomic codes, namely Cowan's HFR, AUTOSTRUCTURE and the Breit-Pauli R-matrix package. This multi-code approach is used to the study the effects of core relaxation, configuration interaction and the Breit interaction, and enables the estimate of statistical accuracy ratings. The Ksigma and KLL Auger widths have been found to be nearly independent of both the outer-electron configuration and electron occupancy keeping a constant ratio of 1.53 +/- 0.06. By comparing with previous theoretical and measured wavelengths, the accuracy of the present set is determined to be within 2 m Angstrom. Also, the good agreement found between the different radiative and Auger data sets that have been computed allow us to propose with confidence an accuracy rating of 20% for the line fluorescence yields greater than 0.01. Emission and absorption spectral features are predicted finding good correlation with measurements in both laboratory and astrophysical plasmas.

Mendoza, C.↗

NASA NTRS2004

Implementation of ALARA radiation protection on the ISS through polyethylene shielding augmentation of the Service Module Crew Quarters

With 5-7 month long duration missions at 51.6 degrees inclination in Low Earth Orbit, the ionizing radiation levels to which International Space Station (ISS) crewmembers are exposed will be the highest planned occupational exposures in the world. Even with the expectation that regulatory dose limits will not be exceeded during a single tour of duty aboard the ISS, the "as low as reasonably achievable" (ALARA) precept requires that radiological risks be minimized when possible through a dose optimization process. Judicious placement of efficient shielding materials in locations where crewmembers sleep, rest, or work is an important means for implementing ALARA for spaceflight. Polyethylene (CnHn) is a relatively inexpensive, stable, and, with a low atomic number, an effective shielding material that has been certified for use aboard the ISS. Several designs for placement of slabs or walls of polyethylene have been evaluated for radiation exposure reduction in the Crew Quarters (CQ) of the Zvezda (Star) Service Module. Optimization of shield designs relies on accurate characterization of the expected primary and secondary particle environment and modeling of the predicted radiobiological responses of critical organs and tissues. Results of the studies shown herein indicate that 20% or more reduction in equivalent dose to the CQ occupant is achievable. These results suggest that shielding design and risk analysis are necessary measures for reducing long-term radiological risks to ISS inhabitants and for meeting legal ALARA requirements. Verification of shield concepts requires results from specific designs to be compared with onboard dosimetry. c2004 COSPAR. Published by Elsevier Ltd. All rights reserved.

NASA Center JSC↗

NASA NTRS2017

Behavioral Health and Performance Laboratory Standard Measures (BHP-SM)

The Spaceflight Standard Measures is a NASA Johnson Space Center Human Research Project (HRP) project that proposes to collect a set of core measurements, representative of many of the human spaceflight risks, from astronauts before, during and after long-duration International Space Station (ISS) missions. The term "standard measures" is defined as a set of core measurements, including physiological, biochemical, psychosocial, cognitive, and functional, that are reliable, valid, and accepted in terrestrial science, are associated with a specific and measurable outcome known to occur as a consequence of spaceflight, that will be collected in a standardized fashion from all (or most) crewmembers. While such measures might be used to define standards of health and performance or readiness for flight, the prime intent in their collection is to allow longitudinal analysis of multiple parameters in order to answer a variety of operational, occupational, and research-based questions. These questions are generally at a high level, and the approach for this project is to populate the standard measures database with the smallest set of data necessary to indicate further detailed research is required. Also included as standard measures are parameters that are not outcome-based in and of-themselves, but provide ancillary information that supports interpretation of the outcome measures, e.g., nutritional assessment, vehicle environmental parameters, crew debriefs, etc. The project's main aim is to ensure that an optimized minimal set of measures is consistently captured from all ISS crewmembers until the end of Station in order to characterize the human in space. -This allows the HRP to identify, establish, and evaluate a common set of measures for use in spaceflight and analog research to: develop baselines, systematically characterize risk likelihood and consequences, and assess effectiveness of countermeasures that work for behavioral health and performance risk factors. -By standardizing the battery of measures on all crewmembers, it will allow the HRP to evaluate countermeasures that work for one physiological system and ensure another system is not negatively affected. -These measures, named "Standard Measures," will serve as a data repository and be available to other studies under data sharing agreements.

Williams, Thomas J.↗

NASA NTRS1978

Carbon Monoxide Sensor

The fuel cell is a system which employs an electrochemical process to convert gases- J such as hydrogen and oxygen directly into electricity. Under NASA sponsorship, GE's Aircraft Equipment Division developed fuel cells to supply electrical power for the Gemini and Biosatellite spacecraft of the sixties and is currently working on advanced fuel cell development. This long-term effort has resulted in a series of spinoff applications using the same general technology for a variety of purposes, among them the recently marketed Dosimeter. The Dosimeter is designed to help users meet safety requirements for industrial atmospheres, as specified by the Occupational Safety and Health Administration and other regulatory agencies. The compact, pocket-sized sensor measures personnel exposure to carbon monoxide and provides both a visual and an audible alarm if the concentration of the gas exceeds present levels. The Dosimeter offers substantial improvement in measuring accuracy over earlier warning indicators.

Source record↗

NASA NTRS1981

Miniature personal UV solar dosimeter

Small light-powered meter measures accumulated radiation in ultraviolet or other selected regions. Practical advantages are device's low cost, small size, accuracy, and adaptability to specific wave-band measurements. Medical applications include detection of skin cancer, vitamin D production, and jaundice. Dosimeter also measures sunlight for solar energy designs, agriculture and meteorology, and monitors stability of materials and environmental and occupational lighting.

Adams, R. R.↗

NASA NTRS2017

Oculomotor Behavior Metrics Change According to Circadian Phase and Time Awake

There is a need for non-invasive, objective measures to forecast performance impairment arising from sleep loss and circadian misalignment, particularly in safety-sensitive occupations. Eye-tracking devices have been used in some operational scenarios, but such devices typically focus on eyelid closures and slow rolling eye movements and are susceptible to the intrusion of head movement artifacts. We hypothesized that an expanded suite of oculomotor behavior metrics, collected during a visual tracking task, would change according to circadian phase and time awake, and could be used as a marker of performance impairment.

sleep deprivation↗

NASA NTRS2020

Occupant Response Analysis of a Full-Scale Crash Test of a Fokker F28 Fellowship Aircraft

In this report, the capability of component fuselage testing and finite element models (FEMs) to predict occupant injury risk when applied to full-scale aircraft crash testing was evaluated. Component level and full-scale crash tests of a Fokker-F28 aircraft were performed in conjunction with representative FEM simulations. Lumbar spine injury risk, calculated through Anthropomorphic Test Device (ATD) outputs measured in the full-scale test, was compared with predictions made by component level testing and simulations. A quantitative assessment of FEM prediction accuracy was made using the International Organization for Standardization (ISO) Technical Report (TR) 16250 curve comparison methodology. Lumbar load injury risk measured in the full-scale test configuration was found to be significantly higher than in the component tests performed. The FEM provided a closer prediction of occupant injury risk than component testing but exhibited limitations in the multi-axis load environment. This work will help inform the application of component testing and FEM simulation when used to evaluate aircraft crashworthiness.

Jacob B Putnam↗

NASA NTRS1953

Accelerations and Passenger Harness Loads Measured in Full-Scale Light-Airplane Crashes

Full-scale light-airplane crashes simulating stall-spin accidents were conducted to determine the decelerations to which occupants are exposed and the resulting harness forces encountered in this type of accident. Crashes at impact speeds from 42 to 60 miles per hour were studied. The airplanes used were of the familiar steel-tube, fabric-covered, tandem, two-seat type. In crashes up to an impact speed of 60 miles per hour, crumpling of the forward fuselage structure prevented the maximum deceleration at the rear-seat location from exceeding 26 to 33g. This maximum g value appeared independent of the impact speed. Restraining forces in the seatbelt - shoulder-harness combination reached 5800 pounds. The rear-seat occupant can survive crashes of the type studied at impact speeds up to 60 miles per hour, if body movement is restrained by an adequate seatbelt-shoulder-harness combination so as to prevent injurious contact with obstacles normally present in the cabin. Inwardly collapsing cabin structure, however, is a potential hazard in the higher-speed crashes.

Eiband, A. Martin↗

NASA NTRS1987

Optical characterization of semi-insulating GaAs - Determination of the Fermi energy, the concentraion of the midgap EL2 level and its occupancy

The key electronic characteristics of semiinsulating GaAs, i.e., the Fermi energy, concentration, and occupancy of the midgap donor EL2, and the net concentration of ionized acceptors can all be determined from high-resolution measurements of the EL2 intracenter absorption. The procedure is based on the measurement of zero-phonon line intensity before and after the complete transfer of EL2 to its metastable state followed by thermal recovery. The procedure is quantitative, involves no fitting parameters, and unlike existing methods, is applicable even when a significant part of the EL2 is ionized.

Lagowski, J.↗