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All sourcesNASA NTRSDOE OSTI
NASA NTRS2023

In Situ Chemical Reduction Interim Measures Work Plan Hot Spot 3 Mobile Launcher Platform Rehabilitation Sites / Vehicle Assembly Building Area (SWMU 056) Kennedy Space Center, Florida

This document presents the design details of an In Situ Chemical Reduction (ISCR) Interim Measures Work Plan for Hot Spot 3 within Mobile Launcher Platform Rehabilitation Sites/Vehicle Assembly Building Area, Solid Waste Management Unit (SWMU) 056 (SWMU 056), located at the John F. Kennedy Space Center, Florida. The interim measures (IM) treatment zone encompasses an area identified as the High Concentration Plume (HCP), which is defined as the area with chlorinated volatile organic compound (CVOC) groundwater concentrations greater than their respective Natural Attenuation Default Concentration (NADC). The objective of the IM is to remove CVOC mass within the treatment area to levels that facilitate a transition to natural attenuation monitoring. The IM design consists of the selected ISCR amendment, Provect-IR, which is a mixture of solid reagents in a single product that promotes enhanced reductive dechlorination and ISCR. ProvectIR includes natural antimethanogenic compounds; multiple hydrophilic, nutrient-rich organic carbon sources; zero valent iron; chemical oxygen scavengers; and vitamin and mineral sources. The proposed treatment area for this IM encompasses less than 1 acre and includes three vertical treatment intervals to reach the NADC plumes that vary per CVOC and depth: 4 to 10 feet below land surface (bls), 10 to 18 feet bls, and 42 to 52 feet bls. The amendment will be distributed through 16 injection points (IP01 through IP16) using dosing rates ranging from 0.4% to 0.6% of soil mass within the treatment interval and a 15% or 20% slurry strength. Dosage rates and slurry strength are based on groundwater geochemistry, soil characteristics, and contaminant concentrations. To aid in the evaluation of the ISCR IM performance, six performance monitoring wells will be installed following injections and sampled semiannually. CVOC parameters will be sampled until concentrations reduce to below their NADC. Underground Injection Control parameters will be sampled until concentrations decrease to background levels or to levels that meet respective groundwater standards. Sampling frequency will be evaluated annually and modified as needed. The path forward for the ISCR IM implementation includes preparing the IM Implementation Work Plan, ISCR injections, monitoring well installation, performance monitoring, and reporting.

Randall K. Sillan↗
DOE OSTI2024

GraMeR: Gra ph Me ta R einforcement learning for multi-objective influence maximization

Influence maximization (IM) is a combinatorial problem of identifying a subset of seed nodes in a network (graph), which when activated, provide a maximal spread of influence in the network for a given diffusion model and a budget for seed set size. IM has numerous applications such as viral marketing, epidemic control, sensor placement and other network-related tasks. However, its practical uses are limited due to the computational complexity of current algorithms. Recently, deep reinforcement learning has been leveraged to solve IM in order to ease the computational burden. However, there are serious limitations in current approaches, including narrow IM formulation that only consider influence via spread and ignore self-activation, low scalability to large graphs, and lack of generalizability across graph families leading to a large running time for every test network. In this work, we address these limitations through a unique approach that involves: (1) Formulating a generic IM problem as a Markov decision process that handles both intrinsic and influence activations; (2)incorporating generalizability via meta-learning across graph families. There are previous works that combine deep reinforcement learning with graph neural network, but this work solves a more realistic IM problem and incorporates generalizability across graphs via meta reinforcement learning. Extensive experiments are carried out in various standard networks to validate performance of the proposed Graph Meta Reinforcement learning (GraMeR) framework. Finally, the results indicate that GraMeR is multiple orders faster and generic than conventional approaches when applied on small to medium scale graphs.

97 MATHEMATICS AND COMPUTING↗
NASA NTRS1985

Recovery in skeletal muscle contractile function after prolonged hindlimb immobilization

The effect of three-month hindlimb immobilization (IM) in rats on contractile properties of slow-twitch soleus (SOL), fast-twitch extensor digitorum longus, and fast-twitch superficial region of the vastus lateralis were measured after 0, 14, 28, 60, and 90 days of recovery on excized, horizontally suspended muscles stimulated electrically to maximal twitch tension. IM caused decreases in muscle-to-body weight ratios for all muscles, with no complete recovery even after 90 days. The contractile properties of the fast-twitch muscles were less affected by IM than those of the slow-twitch SOL. The SOL isometric twitch duration was shortened, due to reduced contraction and half-relaxation time, both of which returned to control levels after 14 days of recovery. The peak tetanic tension, P(O), g/sq cm,, decreased with IM by 46 percent in the SOL, but recovered by the 28th day. The maximum shortening velocity was not altered by IM in any of the muscles. Thus, normal contractile function could recover after prolonged limb IM.

Fitts, R. H.↗
NASA NTRS1991

Determination of C1-C4 alkanes by ion mobility spectrometry

Results are presented from a comparison between two ion-mobility-spectrometer (IMS) methods of sample ionisation: a conventional IMS with very dry helium and an IMS using metastable helium ionization. As one of the tests, a mixture of several hydrocarbons expected to be the components of Titan's atmosphere (made of ethane, ethylene, acetylene, propane, n-butane, isobutane, and propyne in concentrations from 20 to 200 ppm) was analyzed by both methods. Results from the dry-He IMS showed that the dry-helium approach was more adequate for the analysis of these gases than the metastable-helium IMS approach. In the metastable-He approach, in which several versions of He ionization reaction were tested, the spectra produced were not as clear as the conventional IMS spectra, due to the fact that the strong electric field introduced in the reaction region to generate metastable helium affected the gating, resolution, and collection of the ions.

Kojiro, Daniel R.↗
NASA NTRS1994

Human parathyroid hormone-(1-38) restores cancellous bone to the immobilized, osteopenic proximal tibial metaphysis in rats

The purpose of this study was to determine if human parathyroid hormone-(1-38) (PTH) can restore cancellous bone mass to the established osteopenic, immobilized proximal tibial metaphyses (PTM) of female rats. The right hindlimbs of six-month-old female Sprague-Dawley rats were immobilized by bandaging the right hindlimbs to the abdomen. After 30 days of right hindlimb immobilization (RHLI), the rats were subcutaneously injected with 200 microgram hPTH(1-38)/kg/day for 15 (short-term) or 75 (longer-term) days. Static bone histomorphometry was performed on the primary spongiosa, while both static and dynamic histomorphometry were performed on the secondary spongiosa of the right PTM. Immobilization for 30 days without treatment decreased trabecular bone area, number and thickness in both primary and secondary spongiosa, and induced an increase in eroded perimeter and a decrease in tissue referent-bone formation rate (BFR/TV) in the secondary spongios. These changes reached a new steady state thereafter. Treatment with 200 microgram hPTH(1-38)/kg/day for 15 days, beginning at 30 days post immobilization (IM), significantly increased trabecular bone area, thickness and number in both primary and secondary spongiosa despite continuous IM when compared to the age-related and IM controls. The short-term (15 days) PTH treatment significantly increased labeling perimeter, mineral apposition rate and BFR/TV in the secondary spongiosa and stimulated longitudinal bone growth as compared to the age-related and IM controls. PTH treatment for longer-term (75 days) further increased trabecular bone area, thickness and number as compared to aging and IM controls and short-term (15 days) PTH treated groups. The bone formation indices in the secondary spongiosa of these longer-term treated rats were lower than that of short-term (15 days) PTH treated group, but they were still higher than those of IM and age-related controls. Our findings indicate that PTH treatment stimulates cancellous bone formation, restores and adds extra cancellous bone to the established, disuse-osteopenic proximal tibial metaphysis of continuously RHLI female rats. These results suggest that PTH may be a useful agent in treatment disuse-induced osteoporosis in humans.

Ma, Y. F.↗
NASA NTRS1995

Gas chromatography/ion mobility spectrometry as a hyphenated technique for improved explosives detection and analysis

Ion Mobility Spectrometry (IMS) is currently being successfully applied to the problem of on-line trace detection of plastic and other explosives in airports and other facilities. The methods of sample retrieval primarily consist of batch sampling for particulate residue on a filter card for introduction into the IMS. The sample is desorbed into the IMS using air as the carrier and negative ions of the explosives are detected, some as an adduct with a reagent ion such as Cl(-). Based on studies and tests conducted by different airport authorities, this method seems to work well for low vapor pressure explosives such as RDX and PETN, as well as TNT that are highly adsorptive and can be found in nanogram quantities on contaminated surfaces. Recently, the changing terrorist threat and the adoption of new marking agents for plastic explosives has meant that the sample introduction and analysis capabilities of the IMS must be enhanced in order to keep up with other detector developments. The IMS has sufficient analytical resolution for a few threat compounds but the IMS Plasmogram becomes increasingly more difficult to interpret when the sample mixture gets more complex.

Mercado, AL↗
NASA NTRS1996

Development of Ion Mobility Spectrometry for Exobiology Flight Experiments

Ion Mobility Spectrometry (IMS) can provide gas chromatography with sample identification independent of sample retention time, with minimal interface. Initial commercial methods of IMS however, did not possess sufficient analytical capabilities and presented operational parameters which were unsuitable for exobiology missions. Subsequent development of IMS technology, with the focus on exobiology analytical requirements and mission imposed operational limitations, has produced an IMS interfaced with a GC capable of fulfilling the analytical requirements of several exobiology missions. Future exobiology missions will require further development of the IMS, particularly in the areas of overall instrument miniaturization and complex sample identification. The evolution of the exobiology focused IMS will be presented up to the current prototype design, which is a component of several proposed exobiology instruments. Areas of future development will also be discussed.

Kojiro, Daniel R.↗
NASA NTRS2009

General Purpose Data-Driven System Monitoring for Space Operations

Modern space propulsion and exploration system designs are becoming increasingly sophisticated and complex. Determining the health state of these systems using traditional methods is becoming more difficult as the number of sensors and component interactions grows. Data-driven monitoring techniques have been developed to address these issues by analyzing system operations data to automatically characterize normal system behavior. The Inductive Monitoring System (IMS) is a data-driven system health monitoring software tool that has been successfully applied to several aerospace applications. IMS uses a data mining technique called clustering to analyze archived system data and characterize normal interactions between parameters. This characterization, or model, of nominal operation is stored in a knowledge base that can be used for real-time system monitoring or for analysis of archived events. Ongoing and developing IMS space operations applications include International Space Station flight control, satellite vehicle system health management, launch vehicle ground operations, and fleet supportability. As a common thread of discussion this paper will employ the evolution of the IMS data-driven technique as related to several Integrated Systems Health Management (ISHM) elements. Thematically, the projects listed will be used as case studies. The maturation of IMS via projects where it has been deployed, or is currently being integrated to aid in fault detection will be described. The paper will also explain how IMS can be used to complement a suite of other ISHM tools, providing initial fault detection support for diagnosis and recovery.

Satellites↗
NASA NTRS2014

Feasibility Criteria for Interval Management Operations as Part of Arrival Management Operations

Interval Management (IM) is a future airborne spacing concept that aims to provide more precise inter-aircraft spacing to yield throughput improvements and greater use of fuel efficient trajectories for arrival and approach operations. To participate in an IM operation, an aircraft must be equipped with avionics that provide speeds to achieve and maintain an assigned spacing interval relative to another aircraft. It is not expected that all aircraft will be equipped with the necessary avionics, but rather that IM fits into a larger arrival management concept developed to support the broader mixed-equipage environment. Arrival management concepts are comprised of three parts: a ground-based sequencing and scheduling function to develop an overall arrival strategy, ground-based tools to support the management of aircraft to that schedule, and the IM tools necessary for the IM operation (i.e., ground-based set-up, initiation, and monitoring, and the flight-deck tools to conduct the IM operation). The Federal Aviation Administration is deploying a near-term ground-automation system to support metering operations in the National Airspace System, which falls within the first two components of the arrival management concept. This paper develops a methodology for determining the required delivery precision at controlled meter points for aircraft that are being managed to a schedule and aircraft being managed to a relative spacing interval in order to achieve desired flow rates and adequate separation at the meter points.

Levitt, Ian M.↗
NASA NTRS2016

Flight Crew Responses to the Interval Management Alternative Clearances (IMAC) Experiment

Interval Management Alternative Clearances (IMAC) was a human-in-the-loop simulation experiment conducted to explore the efficacy and acceptability of three IM operations: CAPTURE, CROSS, and MAINTAIN. Two weeks of data collection were conducted, with each week using twelve subject pilots and four subject controllers flying ten high-density arrival scenarios into the Denver International Airport. Overall, both the IM operations and procedures were rated very favorably by the flight crew in terms of acceptability, workload, and pilot head down time. However, several critical issues were identified requiring resolution prior to real-world implementation, including the high frequency of IM speed commands, IM speed commands requiring changes to aircraft configuration, and ambiguous IM cockpit displays that did not trigger the intended pilot reaction. The results from this experiment will be used to prepare for a flight test in 2017, and to support the development of an advanced IM concept of operations by the FAA (Federal Aviation Agency) and aviation industry.

Baxley, Brian T.↗
NASA NTRS2012

General Purpose Data-Driven System Monitoring for Space Operations

Modern space propulsion and exploration system designs are becoming increasingly sophisticated and complex. Determining the health state of these systems using traditional methods is becoming more difficult as the number of sensors and component interactions grows. Data-driven monitoring techniques have been developed to address these issues by analyzing system operations data to automatically characterize normal system behavior. The Inductive Monitoring System (IMS) is a data-driven system health monitoring software tool that has been successfully applied to several aerospace applications. IMS uses a data mining technique called clustering to analyze archived system data and characterize normal interactions between parameters. This characterization, or model, of nominal operation is stored in a knowledge base that can be used for real-time system monitoring or for analysis of archived events. Ongoing and developing IMS space operations applications include International Space Station flight control, spacecraft vehicle system health management, launch vehicle ground operations, and fleet supportability. As a common thread of discussion this paper will employ the evolution of the IMS data-driven technique as related to several Integrated Systems Health Management (ISHM) elements. Thematically, the projects listed will be used as case studies. The maturation of IMS via projects where it has been deployed or is currently being integrated to aid in fault detection will be described. The paper will also explain how IMS can be used to complement a suite of other ISHM tools, providing initial fault detection support for diagnosis and recovery

Space Propulsion↗
NASA NTRS2014

Evaluation of Temporal Spacing Errors Associated with Interval Management Algorithms

This paper seeks to characterize the temporal spacing errors resulting from the use of Interval Management (IM) algorithms. The focus of the current paper is IM concepts and algorithms that realize a specified temporal spacing between a Target aircraft and an Ownship aircraft at the runway threshold. The paper presents an IM algorithm consisting of the following four modules: (i) Target-Landing-Time Estimation Module, (ii) Ownship-Landing-Time Estimation Module, (iii) Ownship Speed Command Computation Module, and (iv) Ownship Thrust Command Computation Module. The overall guidance module is evaluated on a simulation that models aircraft point-mass dynamics, bank-angle auto-pilot dynamics, pitch-axis auto-pilot dynamics, and engine lag dynamics. The simulation environment also consists of actual atmospheric forecasts and realistic spatio-temporally correlated wind uncertainty models. Results obtained from single case simulation as well as Monte-Carlo simulations are presented in the paper. The modeled scenario consisted of an A320 Target equipped with “Lateral Navigation”/“Vertical Navigation” (LNAV/VNAV) capabilities followed by an A320 Ownship equipped with the IM algorithm. Both aircraft fly the BIGSUR route to SFO airport using a RAP-13 1-hr wind forecast. 500 Monte-Carlo simulations were conducted with realistic wind uncertainty models. The IM algorithm for this case is seen to have a 90% probability landing time error range of 5.9 seconds, compared to the no-IM solution, which has a 90% probability landing time error range of 33.4 seconds.

Bai, Xiaoli↗
NASA NTRS2020

Contractors Road Heavy Equipment Area (SWMU055) Hot Spot 1 Bioremediation Interim Measure Performance Monitoring And Site-Wide Interim Groundwater Monitoring Report

This document presents a summary of activities completed from January through December 2019 at the Contractors Road Heavy Equipment (CRHE) area, located at John F. Kennedy Space Center (KSC), Florida. The activities summarized include: 1) Annual Hot Spot 1 (HS1) eastern bioremediation interim measure (IM) performance monitoring (December 2019); 2) Annual HS1 western bioremediation IM performance monitoring (December 2019); 3) Annual Interim Groundwater Monitoring (IGM) activities (December 2019); 4) Sub-slab soil gas (SSSG) sampling to investigate potential vapor intrusion (VI) (June 2019). Bioremediation IM activities were implemented in two phases at the CRHE. The first event was implemented in November and December 2016 in the eastern portion of HS1. In April and May 2018, bioremediation IM was implemented in the western portion of HS1. The bioremediation IM targeted chlorinated volatile organic compound (CVOC) concentrations greater than 10 times their Florida Department of Environmental Protection (FDEP) Natural Attenuation Default Criteria (NADC). Bioremediation IM activities included the injection of a diluted solution of SRS®-SD (electron donor) and microbial culture (KB-1®) into the subsurface via direct push technology (DPT) injection down to 50 feet below land surface (ft bls).

Andrew Scott Starr↗
NASA NTRSDate not supplied

Adaptative Site Management for a 115 Acre Chlorinated Solvent Plume with Two Separate Source Areas at Kennedy Space Center, Florida

Background/Objectives. During Resource Conservation and Recovery Act (RCRA) Facility Investigation (RFI) activities, Geosyntec delineated a chlorinated volatile organic compound (CVOC) plume at the National Aeronautics and Space Administration’s (NASA’s) Vehicle Assembly Building (VAB) area located at KSC, Florida. The RFI activities identified an approximate 115-acre dissolved plume (primarily vinyl chloride) and a trichloroethene (TCE) source area in an active aerospace complex that is surrounded by sensitive wetland/waterbodies. Due to the size of the impacted area, the Corrective Measure Design included a multi-component strategy: (i) address the source area via bioremediation; (ii) protect sensitive wetlands from impacted groundwater discharge via biosparging; and (iii) Long Term Monitoring (LTM) of the remaining dissolved plume. After the Corrective Measures implementation (CMI), NASA and Geosyntec worked with Florida Department of Environmental Protection (FDEP) to implement an adaptive site management for the complex, 115-acre site outside of the traditional RCRA process. The adaptive site management approach relied on performing supplemental assessments and implementing Interim Measures (IMs) to further assess and implement remedies over time while working within site and budget constraints, with an overall goal of achieving enough mass reduction to transition the entire site to LTM and eventually achieve site closure. Approach/Activities. After the biosparge barrier was operational and bioremediation within the source area (referred to as Hot Spot 1) achieved the Corrective Action Objective (CAO), supplemental assessment of the area between Hot Spot 1 and the biosparge barrier was performed. The conceptual site model was updated using the supplemental assessment results and an air sparge system IM was designed to treat an approximate 1.2 acre area (referred to as Hot Spot 2). After installation of the air sparge system, supplemental assessment within the remainder of the 115-acre dissolved plume was performed and a second TCE source area was identified. The TCE source area and associated areas with elevated CVOC concentrations (referred to as Hot Spot 3) were delineated and a bioremediation IM was implemented. Also, the downgradient impacts from Hot Spot 3 were adjacent to a sensitive waterbody, and negotiations with the FDEP allowed the area to be monitored using LTM. Results/Lessons Learned. The performance of supplemental assessment activities and implementation of remedial alternatives as IMs allowed NASA to successfully address groundwater impacts over time, while working within the FDEP regulatory framework. The implementation of the CMI and multiple IMs has achieved the following goals: (i) the biosparge barrier has mitigated the potential discharge of impacted groundwater to an adjacent wetland; (ii) enhanced bioremediation within Hot Spot 1 achieved the CAO within 2 years and transitioned the area into LTM; (iii) operation of an air sparge system within Hot Spot 2 removed TCE as a constituent of concern and contributed to a reduction (approximately 43%) in the impacted groundwater area outside the air sparge treatment area (plume collapse); and (iv) bioremediation within Hot Spot 3 removed approximately 80% of the CVOC mass and contributed to a reduction (approximately 47%) in the impacted groundwater area outside the bioremediation IM treatment area. Overall, the adaptive approach is protecting the sensitive water bodies surrounding the complex site and reducing the area of impacted groundwater, which is moving the entire site towards LTM.

Rebecca C Daprato↗
NASA NTRS2024

Converter/Compressor Building Solid Waste Management Unit (SWMU) #89 Monitoring Well 21 Area Interim Measure Work Plan

This Work Plan details the approach and design for the Interim Measure (IM) to remediate groundwater within the MW21 Area where VOC concentrations exceed Florida Department of Environmental Protection Natural Attenuation Default Concentrations. The IM includes in-situ bioremediation via injection of emulsified vegetable oil (EVO) and emulsified zero-valent iron (EZVI). The in-situ bioremediation technology consists of injecting an electron donor substrate into the subsurface to promote microbial breakdown of VOCs. The EVO injections for this IM are designed based on the use of Provectus ERD-CH4, which is a vegetable oil/carbon substrate mixture. The EZVI injections for this IM are designed based on the use of Provectus EZVI-CH4. The IM treatment layout consists of nine injection locations of EVO at approximately 10-foot radius of influence (ROI) and three injections locations of EZVI at approximately 6-foot ROI. The injection method will be direct push using a DPT rig. The overall injection depths range from 7 to 17 ft bls. The 7 ft bls top depth is designed to be 2 ft below the water table to prevent substrates from reaching the top of the water table. Injections are planned to be implemented using 2 ft intervals and will take place using a bottom-up approach to 2 ft below the water table. This work plan further describes the IM design, injection calculations, performance monitoring plan, and provides an injection layout. Revision 1 of this Work Plan includes quarterly performance sampling during Year 1 in accordance with F.A.C. 62-780. These changes are reflected in Section 7 and Table 2 of the Work Plan.

Mark J Jonnet↗
NASA NTRS2024

Hypergol Maintenance Facility North, SWMU 090, Year 3 Air Sparge System Performance Monitoring Report, Kennedy Space Center, Florida

This Performance Monitoring Report (PMR) presents Year 3 Air Sparge (AS) System operation, maintenance, and monitoring (OM&M) activities and performance monitoring results for the AS Interim Measure (IM) at the Hypergol Maintenance Facility North (HMFN) at Kennedy Space Center (KSC), Florida. HMFN has been designated Solid Waste Management Unit (SWMU) 090 under the KSC Resource Conservation and Recovery Act Corrective Action Program. The timeframe for activities included in this report extends from September 2022 to August 2023. The HMFN AS IM was implemented in 2019-2020 to treat a chlorinated solvent groundwater plume that resulted from historical operations supporting the National Aeronautics and Space Administration (NASA) Space Program. The system includes 213 AS wells, with screen depths ranging from 25 feet to 45 feet below land surface (bls) and treats approximately 1.62 acres of contaminated groundwater. The objective of the AS IM is to actively reduce groundwater concentrations exceeding Florida Department of Environmental Protection Natural Attenuation Default Concentrations (NADCs) (identified as the High Concentration Plume [HCP]) to levels that facilitate transition into a Long-Term Monitoring program. The AS IM targets all of the HCP, except for a source zone area within the HCP where trichloroethene (TCE) concentrations exceed 11,000 micrograms per liter (μg/L) at depths greater than 45 feet bls. This is because site lithology was found to not be conducive to the AS treatment technology at these deeper depths. NASA will re-visit plans for potentially utilizing another remedial technology for residual deeper contamination following completion of the AS IM. OM&M activities and results from Year 3 indicate that the AS system at HMFN is operating as designed and is meeting performance criteria. Groundwater performance monitoring results indicate that following the third year of AS system operation, TCE concentrations in wells across all treated depth intervals have been reduced by an average of more than 99 percent. Overall, the areal extent of the plume showed a reduction following Year 3 of AS operations; however, continued operation of the AS system is required to meet the IM objective.

VOCs↗
NASA NTRS1990

Therapeutic effects of antimotion sickness medications on the secondary symptoms of motion sickness

In addition to nausea and vomiting, motion sickness involves slowing of brain waves, loss of performance, inhibition of gastric motility and the Sopite Syndrome. The therapeutic effects of antimotion sickness drugs on these reactions were evaluated. The subjects were rotated to the M-III end-point of motion sickness. Intramuscular (IM) medications were then administered. Side effects before and after rotation were reported on the Cornell Medical Index. Brain waves were recorded on a Grass Model 6 Electroencephalograph (EEG), and gastric emptying was studied after an oral dose of 1 mCi Technetium 99m DTPA in 10 oz. isotonic saline. An increase in dizziness and drowsiness was reported with placebo after rotation. This was not prevented by IM scopolamine 0.1 mg or ephedrine 25 mg. EEG recordings indicated a slowing of alpha waves with some thea and delta waves from the frontal areas after rotation. IM ephedine and dimenhydrinate counteracted the slowing while 0.3 mg scopolamine had an additive effect. Alterations of performance on the pursuit meter correlated with the brain wave changes. Gastric emptying was restored by IM metoclopramide. Ephedrine IM but not scopolamine is effective for some of the secondary effects of motion sickness after it is established.

Wood, C. D.↗
NASA NTRS1992

A different view of plasma flow inside P/Halley

The Giotto spacecraft carried two different instruments - the JPA and the IMS - for the observation of hot ions in the coma of P/Halley. Although there are many similarities in the time and distance profiles of the plasma flow parameters (bulk velocity, number density, and temperature) computed from the two data sets, there are also some significant differences, especially at cometocentric distances less than 500,000 km. The principal discrepancies between the JPA results presented by Formisano et al. (1990) and the IMS observations are: (1) the IMS did not detect the levelling off of the speed and temperature profiles that Formisano et al. interpreted as flow stabilization; (2) the IMS detected differential north-south flow between the solar wind and cometary ions for only a brief interval when the magnetic field was oriented nearly southward, whereas Formisano et al. reported more extensive differential north-south flow that was independent of the direction of the field; (3) the JPA ion densities were factors of 2 to 4 higher than the IMS ion densities which, in turn, were an order of magnitude greater than theoretical values.

Neugebauer, M.↗