j211filtfilt - Zero-Phase Filtering Method that Conforms to SAE J211

No abstract availabl

Stroboscopic Goggles for Reduction of Motion Sickness

A device built around a pair of electronic shutters has been demonstrated to be effective as a prototype of stroboscopic goggles or eyeglasses for preventing or reducing motion sickness. The momentary opening of the shutters helps to suppress a phenomenon that is known in the art as retinal slip and is described more fully below. While a number of different environmental factors can induce motion sickness, a common factor associated with every known motion environment is sensory confusion or sensory mismatch. Motion sickness is a product of misinformation arriving at a central point in the nervous system from the senses from which one determines one s spatial orientation. When information from the eyes, ears, joints, and pressure receptors are all in agreement as to one s orientation, there is no motion sickness. When one or more sensory input(s) to the brain is not expected, or conflicts with what is anticipated, the end product is motion sickness. Normally, an observer s eye moves, compensating for the anticipated effect of motion, in such a manner that the image of an object moving relatively to an observer is held stationary on the retina. In almost every known environment that induces motion sickness, a change in the gain (in the signal-processing sense of gain ) of the vestibular system causes the motion of the eye to fail to hold images stationary on the retina, and the resulting motion of the images is termed retinal slip. The present concept of stroboscopic goggles or eyeglasses (see figure) is based on the proposition that prevention of retinal slip, and hence, the prevention of sensory mismatch, can be expected to reduce the tendency toward motion sickness. A device according to this concept helps to prevent retinal slip by providing snapshots of the visual environment through electronic shutters that are brief enough that each snapshot freezes the image on each retina. The exposure time for each snapshot is less than 5 ms. In the event that a higher rate of strobing is necessary for adequate viewing of the changing scene during rapid head movements, the rate of strobing (but not the exposure time) can be controlled in response to the readings of rate-of-rotation sensors attached to the device

Final NASA Panel Recommendations for Definition of Acceptable Risk of Injury Due to Spaceflight Dynamic Events

A panel of experts was convened in 2010 to help define acceptable injury risk levels for space vehicle launches, landings, and abort scenarios. Classifications of spaceflight-relevant injuries were defined using four categories ranging from minor to severe injury. Limits for each injury category were agreed to, dependent on the expected number of crew exposures in a given vehicle and on whether the flight was considered nominal or off-nominal. Somers et al. captured the findings of this summit in a NASA technical memorandum. This panel was recently re-convened (December 1, 2014) to determine whether the previous recommended injury limits were applicable to newly-designed commercial space flight vehicles. In particular, previous limits were based in part on the number of crew exposures per vehicle and also were sensitive to a definition of nominal and off-nominal vehicle performance. Reconsideration of these aspects led to a new consensus on a definition of injury risk

Motion Sickness Treatment Apparatus and Method

Methods and apparatus are disclosed for treating motion sickness. In a preferred embodiment a method of the invention comprises operating eyewear having shutter lenses to open said shutter lenses at a selected operating frequency ranging from within about 3 Hz to about 50 Hz. The shutter lenses are opened for a short duration at the selected operating frequency wherein the duration is selected to prevent retinal slip. The shutter lenses may be operated at a relatively slow frequency of about 4 Hz when the user is in passive activity such as riding in a boat or car or in limited motion situations in a spacecraft. The shutter lenses may be operated at faster frequencies related to motion of the user's head when the user is active

Application of the Brinkley Dynamic Response Criterion to Spacecraft Transient Dynamic Events

No abstract availabl

Data Mining of Historical Human Data to Assess the Risk of Injury due to Dynamic Loads

The NASA Occupant Protection Group is charged with ensuring crewmembers are protected during all dynamic phases of spaceflight. Previous work with outside experts has led to the development of a definition of acceptable risk (DAR) for space capsule vehicles. The DAR defines allowable probability rates for various categories of injuries. An important question is how to validate these probabilities for a given vehicle. One approach is to impact test human volunteers under projected nominal landing loads. The main drawback is the large number of subject tests required to attain a reasonable level of confidence that the injury probability rates would meet those outlined in the DAR. An alternative is to mine existing databases containing human responses to impact. Testing an anthropomorphic test device (ATD) at the same humanexposure levels could yield a range of ATD responses that would meet DAR. As one aspect of future vehicle validation, the ATD could be tested in the vehicle's seat and suit configuration at nominal landing loads and compared with the ATD responses supported by the human data set. This approach could reduce the number of humanvolunteer tests NASA would need to conduct to validate that a vehicle meets occupant protection standards. METHODS: The U.S. Air Force has recorded hundreds of human responses to frontal, lateral, and spinal impacts at many acceleration levels and pulse durations. All of this data are stored on the Collaborative Biomechanics Data Network (CBDN), which is maintained by the Wright Patterson Air Force Base (WPAFB). The test device for human occupant restraint (THOR) ATD was impact tested on WPAFB's horizontal impulse accelerator (HIA) matching humanvolunteer exposures on the HIA to 5 frontal and 3 spinal loading conditions. No human injuries occurred as a result of these impact conditions. Peak THOR response variables for neck axial tension and compression, and thoracicspine axial compression were collected. Maximal chest deflection was determined from motion capture video of the impact test. HIC 15 and BRIC were calculated from head acceleration responses. Given the number of human subjects for each test condition a confidence interval of injury probability will be obtained. RESULTS: Results will be discussed in terms of injuryrisk probability estimates based on the human data set evaluated. Also, gaps in the data set will be identified. These gaps could be one of two types. One is areas where additional THOR testing would increase the comparable human data set, thereby improving confidence in the injury probability rate. The other is where additional human testing would assist in obtaining information on other acceleration levels or directions. DISCUSSION: The historical human data showed validity of the THOR ATD for supplemental testing. The historical human data are limited in scope, however. Further data are needed to characterize the effects of sex, age, anthropometry, and deconditioning due to spaceflight on risk of injur

Stroboscopic Vision as a Treatment for Space Motion Sickness

Results obtained from space flight indicate that most space crews will experience some symptoms of motion sickness causing significant impact on the operational objectives that must be accomplished to assure mission success. Based on the initial work of Melvill Jones we have evaluated stroboscopic vision as a method of preventing motion sickness. Given that the data presented by professor Melvill Jones were primarily post hoc results following a study not designed to investigate motion sickness, it is unclear how motion sickness results were actually determined. Building on these original results, we undertook a three part study that was designed to investigate the effect of stroboscopic vision (either with a strobe light or LCD shutter glasses) on motion sickness using: (1) visual field reversal, (2) Reading while riding in a car (with or without external vision present), and (3) making large pitch head movements during parabolic flight

Development of rapid diagnostic techniques for idiopathic blindness in the American lobster, Homarus americanus, from eastern Long Island Sound

Idiopathic blindness is a condition that afflicts approximately 50% of the lobsters, Homarus americanus H. Milne-Edwards, 1837, in Long Island Sound (LIS). The condition occurs in lobsters from LIS and Narragansett Bay, but has lower prevalence levels in the Gulf of Maine. Grossly, the condition presents as patches of cloudy, gray-colored regions in the eyes of afflicted animals. Histologically, the ommatidia show signs of altered pigment distribution, necrosis of the optic nerves and rhabdoms, and hemocyte infiltration through the protective basement membrane separating the ommatidia from the optic nerves. Severe lesions show areas with necrotic ommatidia and nearly complete loss of the underlying associated optic nerves. We assessed a rapid, nondestructive, diagnostic technique for determining blindness in lobsters. We compared the use of an otolaryngoscope (o-scope) with stereomicroscopy on live, frozen, and histologically-fixed eyes. Live lobsters from Narragansett Bay, Rhode Island, and off southern Massachusetts were assessed with the o-scope. Right eyes were analyzed via standard histological procedures. Left eyes were frozen and stored at –80 °C, and later thawed and reassessed for blindness. The o-scope had good sensitivity and specificity in diagnosing blindness in the laboratory with good inter-observer comparisons among trained staff. Initial results indicate that the etiological agent of idiopathic blindness is present throughout a large portion of the sound, and that lobsters are probably continually exposed to it. The use of the o-scope as a diagnostic tool will help us better understand the distribution of idiopathic blindness in lobsters from the New England region

A Form of Inherited Cerebellar Ataxia with Saccadic Intrusions, Increased Saccadic Speed, Sensory Neuropathy, and Myoclonus

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72602/1/j.1749-6632.2002.tb02850.x.pd

A Finite Element Model of the THOR-K Dummy for Aerospace and Aircraft Impact Simulations

1) Update and Improve the THOR Finite Element (FE) model to specifications of the latest mod kit (THOR-K). 2) Evaluate the kinematic and kinetic response of the FE model in frontal, spinal, and lateral impact loading conditions