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At least 631 records · Page 35
All sourcesNASA NTRSDOE OSTI
NASA NTRS1985

Torsion resistant grooved joint

A torque tube employing end members interconnected by a tubular member. The end members are provided with a male extension. having radially spaced, axially extending grooves, the number of grooves, outer diameter of the end member, groove width and groove length being in prescribed proportions and ratios. The ends of the tubular member are positioned over the male end member extensions and the tube walls are conformed to the end member· and grooves electromagnetically so that the tube walls are recessed into the grooves.

Aldo Arena↗
NASA NTRS1992

Ventilation-perfusion relationships in the lung during head-out water immersion

Mechanisms of altered pulmonary gas exchange during water immersion were studied in 12 normal males: 6 young (aged 20-29) and 6 older (aged 40-45). It is concluded that, in young subjects with closing volume (CV) less than expiratory reserve volume (ERV), gas exchange was enhanced during immersion, because normal ventilation-perfusion relations were preserved, and by mass balance, the ventilation/O2 uptake changes elevated arterial P(O2). In older males with CV greater than ERV and 52 percent of tidal volume below CV, immersion-induced airways closure during tidal breathing was associated with minimally increased shunt that did not significantly impair gas exchange. It is suggested that airways closure of this degree is of little importance to gas exchange.

Derion, Toniann↗
NASA NTRS1993

Quick acting gimbal joint

An improved linkage assembly provides for locking the pivotable position of one member relative to another member. The linkage assembly permits the unlocking of these members, their subsequent repositioning, and the reliable relocking in a desired position without utilizing tooling. The first member includes a pair of spaced apart support flanges each having a through aperture therein defining a flange female spline. The second member has an end positioned between the pair of support flanges and also includes a through aperture defining a pair of second member female splines. A pair of control members are each slidably moveable along the common axis and extend through the respective flanges. Each control member has a male splined portion which normally engages both the respective flange female spline and the second member female spline to lock the rotatable position of the first and second members. When each of the control members are pressed inward simultaneously, the male splined portions disengage the flange female splines to permit rotation of the first member about the common axis with respect to the second member.

William B Wood↗
NASA NTRS1993

Anthropometric data from launch and entry suited test subjects for the design of a recumbent seating system

Returning space crews to Earth in a recumbent position requires the design of a new seating system. Current anthropometric data are based on measurements taken while the subjects were unsuited and sitting. To be most accurate, it is necessary to design by measurements of subjects in the launch and entry suit in a recumbent position. Since the design of the recumbent seating system must meet the requirements of both 5th percentile Japanese female and 95th percentile American male crew members, a delta is reported rather than absolute measurements of the test subjects. This delta is the difference in the measurements taken with the subjects unsuited and sitting and those taken with the subjects suited and recumbent. This delta, representative of the change due to the suit, can be added to the existing Man-Systems Integration Standards (NASA-STD-3000) anthropometric data to project the measurements for 5th percentile Japanese female and 95th percentile American male crew members. A delta accounting for the spinal elongation caused by prolonged exposures to microgravity is added as well. Both unpressurized and pressurized suit conditions are considered. Background information, the test protocol and procedure, analysis of the data, and recommendations are reported.

Stoycos, Lara E.↗
NASA NTRS1993

The Visible Human Project of the National Library of Medicine: Remote access and distribution of a multi-gigabyte data set

As part of the 1986 Long-Range Plan for the National Library of Medicine (NLM), the Planning Panel on Medical Education wrote that NLM should '...thoroughly and systematically investigate the technical requirements for and feasibility of instituting a biomedical images library.' The panel noted the increasing use of images in clinical practice and biomedical research. An image library would complement NLM's existing bibliographic and factual database services and would ideally be available through the same computer networks as are these current NLM services. Early in 1989, NLM's Board of Regents convened an ad hoc planning panel to explore possible roles for the NLM in the area of electronic image libraries. In its report to the Board of Regents, the NLM Planning Panel on Electronic Image Libraries recommended that 'NLM should undertake a first project building a digital image library of volumetric data representing a complete, normal adult male and female. This Visible Human Project will include digitized photographic images for cryosectioning, digital images derived from computerized tomography, and digital magnetic resonance images of cadavers.' The technologies needed to support digital high resolution image libraries, including rapid development; and that NLM encourage investigator-initiated research into methods for representing and linking spatial and textual information, structural informatics. The first part of the Visible Human Project is the acquisition of cross-sectional CT and MRI digital images and cross-sectional cryosectional photographic images of a representative male and female cadaver at an average of one millimeter intervals. The corresponding cross-sections in each of the three modalities are to be registerable with one another.

Ackerman, Michael J.↗
NASA NTRS1994

Spline-Screw Payload-Fastening System

Payload handed off securely between robot and vehicle or structure. Spline-screw payload-fastening system includes mating female and male connector mechanisms. Clockwise (or counter-clockwise) rotation of splined male driver on robotic end effector causes connection between robot and payload to tighten (or loosen) and simultaneously causes connection between payload and structure to loosen (or tighten). Includes mechanisms like those described in "Tool-Changing Mechanism for Robot" (GSC-13435) and "Self-Aligning Mechanical and Electrical Coupling" (GSC-13430). Designed for use in outer space, also useful on Earth in applications needed for secure handling and secure mounting of equipment modules during storage, transport, and/or operation. Particularly useful in machine or robotic applications.

Vranish, John M.↗
NASA NTRS1993

Physiological Anatomical Rodent Experiment (PARE) .04 Feasibility Test 1

The objective of this feasibility study was to investigate the environmental/treatment stresses in the proposed PARE.04 experiments in a ground based study to determine if these stresses were of sufficient magnitude to compromise the planned shuttle experiments. Eighty pregnant Sprague-Dawley rats were received on day 2 (day l equals day of vaginal plug) of gestation (G2) and on G7 60 were laparotomized to determine the condition of pregnancy and allow assignment to test groups. The five test groups (N equals 10 each group) were as follows: Group 1, nominal flight; Group 2, laparotomy control; Group 3, hysterectomy control; Group 4, vivarium control; Group 5, caesarean delivery. On G17, groups 1, 2, and 5 were subjected to unilateral hysterectomy to obtain fetuses for evaluation. There was no difference in fetal crown-rump length, fetal weight, or placental weight in any of the test groups subjected to unilateral hysterectomy at G17. Animals were allowed to go to term and animals in each group delivered between the morning of G22 and the afternoon of G23. Rats assigned to Group 5 began delivering vaginally prior to the designated time for caesarean section, thus only 2 animals in this group were delivered by caesarean section. After delivery, a blood sample was taken from the dam, and they were euthanized and the thymus and adrenal glands weighed. Pups from experimental dams were tattooed for identification, the anogenital distance of male pups was photographed for later measurement, and all pups placed with foster dams and litter sizes were standardized to 10. On day 7, all pups were euthanized, and pup adrenal glands and thymus weighed. Laparotomy at G7 with or without unilateral hysterectomy at G17, had no effect on pregnancy maintenance or vaginal delivery. There was no difference in maternal adrenal or thymus weights or plasma levels of catecholamines, estradiol, progesterone, or corticosterone. Likewise, there was no difference in the anogenital distance (index of fetal stress) of neonatal male pups, between any of the experimental groups. From days 0-7, weight gain from dams in all experimental groups was similar. Lastly, there was no difference in weights of thymus and adrenal glands in pups euthanized at day 7. Collectively, these data indicate that treatment stresses inherent in the proposed PARE.04 experimental design should not compromise the planned shuttle experiments.

Burden, Hubert W.↗
NASA NTRS1993

Cooling apparatus and couplings therefor

The present invention relates generally to the field of thermal transfer and, more specifically, to a direct-interface, fusible heat sink for non-venting, regenerable, and self-contained thermal regulation. A quick connect coupling includes a male and a female portion. The female portion is frozen in a container of solid-phase coolant fluid, i.e., water, so that passages in the housing are blocked by ice initially. The ice is melted by direct interface with liquid coolant fluid delivered from the male portion. The present invention has advantages in that the phase change material remains sealed at all times, including during regeneration. Also, it uses quick-disconnect couplings that allow the phase change material to completely fill the container and is easily handled in microgravity without spills, leakage, or handling of phase change material.

Lomax, Curtis↗
NASA NTRS1990

Experimental studies of gastric dysfunction in motion sickness: The effect of gastric and vestibular stimulation on the vagal and splanchnic gastric efferents

The susceptibility of rhesus monkeys to motion sickens was investigated using test conditions that are provocative for eliciting motion sickness in squirrel monkeys. Ten male rhesus monkeys and ten male Bolivian squirrel monkeys were rotated in the vertical axis at 150°/s for a maximum duration of 45 min. Each animal was tested in two conditions, continuous rotation and intermittent rotation. None of the rhesus monkeys vomited during the motion tests but all of the squirrel monkeys did. Differences were observed between the species in the amount of activity that occurred during motion tests, with the squirrel monkeys being significantly more active than the rhesus monkeys. These results, while substantiating anecdotal reports of the resistance of rhesus monkeys to motion sickness, should be interpreted with caution because of the documented differences that exist between various species with regard to stimuli that are provocative for eliciting motion sickness.

Meryl L Corcoran↗
NASA NTRS1994

Physiological Anatomical Rodent Experiment (PARE) .04 feasibility test 2

The objective of this feasibility study was to subject pregnant rats of the same age, strain, and size that will be utilized in a shuttle flight experiment to all flight conditions except the unique microgravity of space flight and determine the feasibility of the proposed experimental design to meet the experimental objectives. The study utilized facilities at NASA, Ames Research Center, Moffett Field, CA to subject the rats to the gravitational stresses of a simulated shuttle launch and simulated shuttle landing. One hundred pregnant rats were received on gestation day (G) 2 (day 1 = day of vaginal sperm) and on G7, eighty rats were laparotomized to determine the condition of pregnancy and allow assignment to test groups. The five test groups (N=10 each group) were as follows: Group 1, Nominal Flight; Group 2, Laparotomy Control; Group 3, Hysterectomy Control; Group 4, Vivarium Control; Group 5, Delayed Recovery. On G9, animals in groups 1,2,3, and 5 were subjected to a shuttle launch simulation. On G18, groups 1,2, and 3 were subjected to a shuttle landing simulation and on this same day groups 1 and 2 were subjected to unilateral hysterectomy to obtain fetuses and placentas for evaluation. Fetal crown-rump length and fetal weight of the Nominal Flight group was significantly less than the Laparotomy Control group, but placentas were similar. On G20, group 5 was subjected to a shuttle landing simulation and on this day this group received a unilateral hysterectomy and fetuses and placentas were weighed. Animals in all groups were allowed to go to term and all animals delivered between 06:00 hours G22 and 18:00 hours G23. After delivery, a blood sample was taken from each experimental dam, and they were euthanized and the thymus and adrenal glands weighed. The thymus weight from all experimental group dams was decreased relative to the Vivarium Control group but adrenal glands and hormone values in dam plasma was similar in all groups. Pups from experimental groups were tattooed for identification, the anogenital distance of male pups was measured, and all pups placed with foster dams and litter sizes were standardized to 10. There was no difference in anogenital distances between male pups from different test groups. Pups delivered from Delayed Recovery animals were smaller than pups delivered from Nominal Flight animals. On neonatal day 7, all pups were euthanized and pup adrenal glands and thymus weighed. There was no difference in weights of thymus and adrenal glands in pups euthanized at neonatal day 7. Collectively, these data confirm the feasibility of the experimental design to meet objectives of the studies proposed for shuttle flight.

Burden, Hubert W.↗
NASA NTRS1994

Slip joint connector

A slip joint connector for joining first and second structural elements together is presented. The connector has a first body member attachable to the first structural element and a second body member attachable to the second structural element. The first body member has a male protuberance including a conical portion and the second body member has a conical receptacle for cooperatively receiving the conical portion of the protuberance. The protuberance includes a bridging portion for spacing the conical portion from the remainder of the first body member and the second body member has a well communicating with the conical receptacle for receiving the bridging portion. The conical male portion internally carries a nut while the second body member may receive a bolt through the receptacle to be threadedly received by the nut to secure the first and second body members tightly together.

Thomas, Frank P.↗
NASA NTRS1992

Magnetic Resonance Imaging (MRI) of skeletal muscles in astronauts after 9 days of space flight

Skylab data indicated that prolonged exposure of human subjects to microgravity environment causes significant muscle atrophy accompanied by reduced muscle strength and fatigue resistance. The objective of this study was to determine decrements in muscle size, if any, in the soleus and gastrocnemius muscles of male and female astronauts after 9 days of space flight. Methods: Eight astronauts, one female and seven male, between the ages of 31 and 59 years 59-84 kg in body weight were examined by MRI 2-3 times preflight within 16 days before launch, and 2 days, (n=6) and seven days (n=3) after landing. The right leg muscles (gastroc-soleus) were imaged with a lower extremity coil in magnets operating at 1.0 or 1.5 Tsela. The imaging protocol consisted of spin echo with a Tr of 0.70 - 1.5 sec. Thirty to forty 3-5 mm thick slices were acquired in 256 x 128 or 256 x 256 matrices. Acquisition time lasted 20-40 minutes. Multiple slices were measured by computerized planimetry. Results: Compared to the preflight, the cross-sectoral areas (CSA) of the soleus, gastrocnemius, and the leg, at 2 days after landing were reduced (at least p less than 0.05) 8.9 percent, 13.2 percent, and 9.5 percent respectively. The soleus and the leg of three astronauts evaluated at 7 days postflight did not show full recovery compared to the preflight values. Conclusions: It is concluded that l9-days of space flight may cause significant decreases in CSA of the leg muscles. The factors responsible for this loss need further determination.

Jaweed, M.↗
NASA NTRS1994

US experiments flown on the Soviet biosatellite Cosmos 2044. Volume 1: Mission description, experiments K-7-01 - K-7-15

Cosmos 2044 was launched on September 15, 1989, containing radiation dosimetry experiments and a biological payload including two young male rhesus monkeys, ten adult male Wistar rats, insects, amphibians, protozoa, cell cultures, worms, plants and fish. The biosatellite was launched from the Plesetsk Cosmodrome in the Soviet Union for a mission duration of 14 days, as planned. The major research objectives were: (1) Study adaptive response mechanisms of mammals during flight; (2) Study physiological mechanisms underlying vestibular, motor system and brain function in primates during early and later adaptation phases; (3) Study the tissue regeneration processes of mammals; (4) Study the development of single-celled organisms, cell cultures and embryos in microgravity; (5) Study radiation characteristics during the mission and investigate doses, fluxes and spectra of cosmic radiation for various types of shielding. American and Soviet specialists jointly conducted 29 experiments on this mission including extensive preflight and post flight studies with rhesus monkeys, and tissue processing and cell culturing post flight. Biosamples and data were subsequently transferred to the United States. The U.S. responsibilities for this flight included development of flight and ground-based hardware, the preparation of rat tissue sample procedures, the verification testing of hardware and experiment procedures, and the post flight analysis of biospecimens and data for the joint experiments. The U.S. investigations included four primate experiments, 24 rat experiments, and one radiation dosimetry experiment. Three scientists investigated tissue repair during flight for a subgroup of rats injured preflight by surgical intervention. A description of the Cosmos 2044 mission is presented in this report including preflight, on-orbit and post flight activities. The flight and ground-based bioinstrumentation which was developed by the U.S. and U.S.S.R. is also described, along with the associated preflight testing of the U.S. hardware.

Connolly, James P.↗
NASA NTRS1993

Solar particle dose rate buildup and distribution in critical body organs

Human body organs have varying degrees of radiosensitivity as evidenced by radioepidemiologic tables. The major critical organs for both the male and female that have been identified include the lung, thyroid, stomach, and breast (female). Using computerized anatomical models of the 50th percentile United States Air Force male and female, we present the self-shielding effects of these various body organs and how the shielding effects change as the location (dose point) in the body varies. Several major solar proton events from previous solar cycles and several events from the current 22nd solar cycle have been analyzed. The solar particle event rise time, peak intensity, and decay time vary considerably from event to event. Absorbed dose and dose equivalent rate calculations and organ risk assessment data are presented for each critical body organ. These data are compared with the current NASA astronaut dose limits as recommended by the National Council on Radiation Protection and Measurements.

Atwell, William↗
NASA NTRS1998

Applying Space Technology to Enhance Control of an Artificial Arm for Children and Adults With Amputations

The first single function myoelectric prosthetic hand was introduced in the 1960's. This hand was controlled by the electric fields generated by muscle contractions in the residual limb of the amputee user. Electrodes and amplifiers, embedded in the prosthetic socket, measured these electric fields across the skin, which increase in amplitude as the individual contracts their muscle. When the myoelectric signal reached a certain threshold amplitude, the control unit activated a motor which opened or closed a hand-like prosthetic terminal device with a pincher grip. Late in the 1990's, little has changed. Most current myoelectric prostheses still operate in this same, single-function way. To better understand the limitations of the current single-function myoelectric hand and the needs of those who use them, The Institute for Rehabilitation and Research (TIRR), sponsored by the National Institutes of Health (NUH), surveyed approximately 2,500 individuals with upper limb loss [1]. When asked to identify specific features of their current myoelectric prostheses that needed improvement, the survey respondents overwhelmingly identified the lack of wrist and finger movement, as well as poor control capability. However, simply building a mechanism with individual finger and wrist motion is not enough. In the 1960's and 1970's, engineers built a number of more dexterous prosthetic hands. Unfortunately, these were rejected during clinical trials due to a difficult and distracting control interface. The goal of this project, "Applying Space Technology to Enhance Control of an Artificial Arm for Children and Adults with Amputations," was to lay the foundation for a multi-function, intuitive myoelectric control system which requires no conscious thought to move the hand. We built an extensive myoelectric signal database for six motions from ten amputee volunteers, We also tested a control system based on new artificial intelligence techniques on the data from two of these subjects. This data is available to anyone doing myoelectric control research. Its availability is an important contribution to the prosthetics research community, as many researchers do not have access to amputee subjects. Since we collected myoelectric data from subjects' sound arms as well as their residual arms, this database will also prove useful to virtual reality and robotics researchers who want to explore myoelectric-based interfaces between any user and a machine. Currently, one small company (Intelligenta, Inc.) and one university (University of New Brunswick, Canada) are using this myoelectric database under other funding to develop multifunction control systems for prostheses. A prosthetics manufacturer (Liberty Technology, Inc.) is making plans to incorporate the results of their work into an artificial hand capable of several different movements to provide functionality only dreamed of by current myoelectric users. Methods Six adults and four children, all with unilateral, below-elbow amputations served as subjects. Five of the adults (3 male, 2 female, average age 34 years) had amputations due to traumatic injury, while one adult (female, age 32 years) and the four children (3 male, 1 female, average age 13 years) had congenital (i.e. from birth) limb deficiencies.

Atkins, Diane J.↗
NASA NTRS1999

Using Transom Jack in the Human Engineering Analysis of the Materials Science Research Rack-1 and Quench Module Insert

This paper describes the human engineering analysis performed on the Materials Science Research Rack-1 and Quench Module Insert (MSRR-1/QMI) using Transom Jack (Jack) software. The Jack software was used to model a virtual environment consisting of the MSRR-1/QMI hardware configuration and human figures representing the 95th percentile male and 5th percentile female. The purpose of the simulation was to assess the human interfaces in the design for their ability to meet the requirements of the Pressurized Payloads Interface Requirements Document - International Space Program, Revision C (SSP 57000). Jack was used in the evaluation because of its ability to correctly model anthropometric body measurements and the physical behavior of astronauts working in microgravity, which is referred to as the neutral body posture. The Jack model allows evaluation of crewmember interaction with hardware through task simulation including but not limited to collision avoidance behaviors, hand/eye coordination, reach path planning, and automatic grasping to part contours. Specifically, this virtual simulation depicts the human figures performing the QMI installation and check-out, sample cartridge insertion and removal, and gas bottle drawer removal. These tasks were evaluated in terms of adequate clearance in reach envelopes, adequate accessibility in work envelopes, appropriate line of sight in visual envelopes, and accommodation of full size range for male and female stature maneuverability. The results of the human engineering analysis virtual simulation indicate that most of the associated requirements of SSP 57000 were met. However, some hardware design considerations and crew procedures modifications are recommended to improve accessibility, provide an adequate work envelope, reduce awkward body posture, and eliminate permanent protrusions.

Dunn, Mariea C.↗
NASA NTRS1999

CO2 Accumulation in the Non-Conformal Helmet of the NASA Launch and Entry Suit During Simulated Unaided Egress

The Launch and Entry Suit (LES) has been worn by astronauts since 1988 for Space Shuttle launch and landing. Previous work indicated that carbon dioxide (CO2) accumulation in the LES non-conformal helmet might be high during locomotion while wearing the LES. The purpose of this study was to characterize the inspired CO2%, metabolic requirements, and egress performance during a simulation of an unaided egress from the Space Shuttle in healthy male subjects wearing the LES and walking on a treadmill. With the helmet visor closed, 12 male subjects completed a 6-min seated prebreathe with 100% O2 followed by a 2-min stand and 5 min of walking at 1.56 m/sec (5.6 km/h, 3.5 mph) as a simulation of unaided egress. All subjects walked with four different G-suit pressures (0.0, 0.5, 1.0, 1.5 psi). After a 10-min recovery, subjects walked 5 min with the same G-suit pressure and helmet visor open for the measurement of metabolic rate (VO2). When G-suit inflation levels were 1.0 or 1.5 psi, only 4 of our 12 healthy, non-micro-gravity exposed subjects completed the unaided egress. Inspired CO2 levels greater than 4% were routinely observed during walking. The metabolic cost at the 1.5 psi G-suit inflation was over 135% of the metabolic cost at 0.0 psi inflation. During unaided egress, G-suit inflation pressures of 1.0 (required inflation for missions greater than 11 days) and 1.5 psi resulted in elevated CO2 in the LES helmet and increased metabolic cost of walking, either of which could impact unaided egress by returning space flight crews.

Greenisen, M. C.↗
NASA NTRS2000

Statistical Analysis of Risk Factors in the Prebreathe Reduction Protocol

The 165 exposures from four 2-hour protocols were analyzed for correlations or trends between decompression sickness (DCS) or venous gas emboli (VGE), and variables that affect risk in the subject and astronaut populations. The assumption in this global survey is that the distributions of gender, age, body mass index, etc., are equally represented in all four tested procedures. We used Student t-test for comparisons between means and chi-square test between comparisons of proportions with p<0.05 defining a significant level. The type and distribution of the 19 cases of DCS were similar to historical cases. There was no correlation of age, gender, body mass index or fitness level with greater incidence of DCS or VGE. However increased age was associated with more Grade IV VGE in males. The duration and quantity of exercise during prebreathe is inversely related to risk of DCS and VGE. The latency time for VGE was longer (103 min +/- 56 SD, n = 15) when the ergometry was done approximately 15 min into the prebreathe than when done at the start of the prebreathe (53 min +/- 31, n = 13). The order of the ergometry did not influence the overall DCS and VGE incidence. We identified variables other than those of the prebreathe procedures that influence the DCS and VGE outcome. The analysis suggests that males over 40 years have a high incidence of Grade IV VGE.

Gerth, Wayne A.↗