454 research outputs found
Space Radiation Effects on Inflatable Habitat Materials Project
The Space Radiation Effects on Inflatable Habitat Materials project provides much needed risk reduction data to assess space radiation damage of existing and emerging materials used in manned low-earth orbit, lunar, interplanetary, and Martian surface missions. More specifically, long duration (up to 50 years) space radiation damage will be quantified for materials used in inflatable structures (1st priority), as well as for habitable composite structures and space suits materials (2nd priority). The data acquired will have relevance for nonmetallic materials (polymers and composites) used in NASA missions where long duration reliability is needed in continuous or intermittent radiation fluxes. This project also will help to determine the service lifetimes for habitable inflatable, composite, and space suit materials
Smart Composite Overwrapped Pressure Vessel - Integrated Structural Health Monitoring System to Meet Space Exploration and International Space Station Mission Assurance Needs
Currently there are no integrated NDE methods for baselining and monitoring defect levels in fleet for Composite Overwrapped Pressure Vessels (COPVs) or related fracture critical composites, or for performing life-cycle maintenance inspections either in a traditional remove-and-inspect mode or in a more modern in situ inspection structural health monitoring (SHM) mode. Implicit in SHM and autonomous inspection is the existence of quantitative accept-reject criteria. To be effective, these criteria must correlate with levels of damage known to cause composite failure. Furthermore, implicit in SHM is the existence of effective remote sensing hardware and automated techniques and algorithms for interpretation of SHM data. SHM of facture critical composite structures, especially high pressure COPVs, is critical to the success of nearly every future NASA space exploration program as well as life extension of the International Space Station. It has been clearly stated that future NASA missions may not be successful without SHM [1]. Otherwise, crews will be busy addressing subsystem health issues and not focusing on the real NASA missio
Strategies for the detection of designer steroids in racehorses
Anabolic androgenic steroids (AAS) are a class of compounds which
include the parent compound testosterone, and are well-known for
their misuse as performance enhancing substances in sport. Over
the last decade there has a push towards the illicit use of
so-called âdesigner steroidsâ which are manufactured with the
express aim of rendering these compounds undetectable by existing
anti-doping methods. These compounds are readily accessible
online in âdietaryâ or ânutritionalâ supplements
containing compounds which have never been tested or approved as
veterinary agents. Despite considerable focus in human sports,
there has been limited investigation into these compounds in
equine systems. As such, developing new tools to detect these
compounds is of high priority.
Chapter One presents a summary of the literature detailing the
metabolism of designer steroid compounds in equine systems, with
an aim to identify metabolites suitable for incorporation into
screening protocols by anti-doping laboratories. Future
directions for anti-doping laboratories are also proposed,
highlighting the importance of alternate testing matrices,
improved in vitro methodologies which can faithfully replicate in
vivo metabolism, and the development of untargeted screening
methods which can detect new instances of steroid misuse.
Chapter Two presents new methodology for the synthesis of steroid
sulfate compounds, suitable for use in analytical laboratories.
Key to this synthetic methodology is the use of solid-phase
extraction (SPE), a technique routinely used in anti-doping
laboratories but with untapped potential in chemical synthesis.
This methodology was applied to the synthesis of sixteen steroid
mono-sulfate, and twelve steroid bis-sulfate reference materials,
which encompass a representative range of steroid substitution
patterns and configurations. The mass spectrometry behaviour of
these bis-sulfate compounds has been studied, and used to develop
a constant ion loss (CIL) scan method for the untargeted
detection of all major classes of steroid bis-sulfate
metabolites.
Chapter Three presents a study detailing the discovery of a novel
anabolic agent 3ι/β-chloro-17ι-methyl-5ι-androstan-17β-ol,
in samples seized by law-enforcement, and the subsequent
investigations to elucidate its structure, identify the primary
human and equine metabolites, and to incorporate these into
routine anti-doping screening protocols. This study highlights a
workflow suitable for adoption by anti-doping laboratories which
allows for the development of suitable screening protocols in the
event that new designer steroids are identified.
Chapter Four presents in vivo and in vitro studies of the
designer steroid furazadrol
([1â,2â]isoxazolo[4â,5â:2,3]-5Îą-androstan-17β-ol).
Following a controlled equine in vivo administration, these
investigations have identified the key urinary metabolites of
furazadrol, many of which have been confirmed by comparison to
synthetically-derived reference materials. These metabolites can
be incorporated into anti-doping screening and confirmation
procedures. Comparative in vitro studies were also undertaken
alongside this work. A second study is presented in this chapter
which investigates alternative conditions for in vitro phase II
metabolism, and employs adenosine 5â-triphosphate (ATP) and
Na2SO4 in place of the expensive phase II co-factor
3'-phosphoadenosine-5'-phosphosulfate (PAPS). Although the
ability to replicate in vivo metabolism using in vitro methods is
currently limited, it is hoped that this work will allow for the
prediction of in vivo metabolism of unknown compounds solely from
in vitro results.
Chapter Five presents an in vivo study of the designer steroid
hemapolin (2ι,3ι-epithio-17ι-methyl-5ι-androstan-17β-ol).
Following a controlled equine in vivo administration, these
investigations have identified the key urinary metabolites of
hemapolin, many of which have been confirmed by comparison to an
extensive library of synthetically-derived reference materials.
The excretion profiles of the major enone metabolites
17β-hydroxy-17ι-methyl-5ι-androst-3-en-2-one, and
17β-hydroxy-17ι-methyl-5ι-androst-2-en-4-one have been
established through a MRM method. These metabolites can be
incorporated into anti-doping screening and confirmation
procedures, allowing for the future detection of hemapolin
misuse
Impact of Extreme Heat Events on Emergency Department Visits in North Carolina (2007â2011)
Extreme heat is the leading cause of w eather-related mortality in the U.S. Extreme heat also affects human health through heat stress and can exacerbate underlying medical conditions that lead to increased morbidity and mortality. In this study, data on emergency department (ED) visits for heat-related illness (HRI) and other selected diseases were analyzed during three heat events across North Carolina from 2007 to 2011. These heat events were identified based on the issuance and verification of heat products from local National Weather Service forecast offices (i.e. Heat Advisory, Heat Watch, and Excessive Heat Warning). The observed number of ED visits during these events were compared to the expected number of ED visits during several control periods to determine excess morbidity resulting from extreme heat. All recorded diagnoses were analyzed for each ED visit, thereby providing insight into the specific pathophysiological mechanisms and underlying health conditions associated with exposure to extreme heat. The most common form of HRI was heat exhaustion, while the percentage of visits with heat stroke was relatively low (65 years of age) were at greatest risk for HRI during the early summer heat event (8.9 visits per 100,000), while young and middle age adults (18â44 years of age) were at greatest risk during the mid-summer event (6.3 visits per 100,000). Many of these visits were likely due to work-related exposure. The most vulnerable demographic during the late summer heat event was adolescents (15â17 years of age), which may relate to the timing of organized sports. This demographic also exhibited the highest visit rate for HRI among all three heat events (10.5 visits per 100,000). Significant increases (p < 0.05) in visits with cardiovascular and cerebrovascular diseases were noted during the three heat events (3â8 %). The greatest increases were found in visits with hypotension during the late summer event (23 %) and sequelae during the early summer event (30 %), while decreases were noted for visits with hemorrhagic stroke during the middle and late summer events (13â24 %) and for visits with aneurysm during the early summer event (15 %). Significant increases were also noted in visits with respiratory diseases (5â7 %). The greatest increases in this category were found in visits with pneumonia and influenza (16 %), bronchitis and emphysema (12 %), and COPD (14 %) during the early summer event. Significant increases in visits with nervous system disorders were also found during the early summer event (16 %), while increases in visits with diabetes were noted during the mid-summer event (10 %)
Initiatives to Improve Quality of Additively Manufactured Parts
NASA is providing leadership in an international effort linking government and industry resources to speed adoption of additive manufactured (AM) parts. Participants include government agencies (NASA, USAF, NIST, FAA), industry (commercial aerospace, NDE manufacturers, AM equipment manufacturers), standards organizations and academia. NASA is also partnering with its international space exploration organizations such as ESA and JAXA. NDT is identified as a universal need for all aspects of additive manufacturing
A Study of Nektonic and Benthic Faunas of the Shallow Gulf of Mexico Off the State of Mississippi As Related to Some Physical, Chemical, and Geological Factors
A seasonal study of the nektonic and benthic faunas of the shallow Gulf of Mexico off Mississippi was conducted from January 1967 through May 1969. It was planned to sample monthly six fixed offshore stations at depths ranging from 5 to 50 fathoms in the open Gulf. In general this was carried out fairly well.
Water samples were taken from surface, midwater, and bottom levels each time a station was occupied, and temperatures and salinities were recorded for each of these. Samples were tested for the presence of nitrates, nitrites, ortho-phosphates and total phosphates. Secchi disc extinction points were recorded. Grab samples were taken for the determination of bottom composition.
Plankton samples were taken from surface, midwater and bottom levels. Copepods, brachyuran zoea and megalops, stomatopod larvae, Lucifer faxoni, Acetes a. carolinae, Penilia avirostris, Doliolum sp. and fish eggs and larvae were present in greatest abundance.
Surface and benthic nekton samples were obtained. Dredge samples were made quarterly and twelve invertebrate species and three species of fishes were collected. Renilla mĂźlleri was the most abundant species taken, and the fish catch consisted of Centropristes ocyurus, Citharichthys spilopterus and Etropus crossotus.
Accounts of 50 invertebrate species (24,679 specimens) and 129 fishes (93,563 specimens) taken in trawl hauls is presented. Temperature and salinity data are given for all species. Relative abundance, seasonal bathymetric distributions and movements, apparent growth patterns, catch per unit of effort and various biological data are noted for the most abundant species. Station 5 (40 fathoms) produced the largest percentage of trawl catches (22.7). Renilla mĂźlleri was the most abundant invertebrate taken in trawling. The brown shrimp, Penaeus aztecus, was second in abundance (10.92%). The five most abundant species comprising 80.57% numerically of the catch were croaker, longspine porgy, butterfish, spot, and seatrout. The species comprising 91.89% of the catch by weight were the croaker, longspine porgy, spot, seatrout, lizardfish, butterfish, pinfish, bank sea bass, sea catfish and black fin sea robin. The families Sciaenidae, Sparidae and Stromateidae were represented by the greatest numbers and comprised 82.9% of the total catch. Families considered to be of commercial importance contributed 92.9% to the total fish catch
Use of Statistical Analysis of Acoustic Emission Data on Carbon-Epoxy COPV Materials-of-Construction for Enhanced Felicity Ratio Onset Determination
Broadband modal acoustic emission (AE) data were acquired during intermittent load hold tensile test profiles on Toray T1000G carbon fiber-reinforced epoxy (C/Ep) single tow specimens. A novel trend seeking statistical method to determine the onset of significant AE was developed, resulting in more linear decreases in the Felicity ratio (FR) with load, potentially leading to more accurate failure prediction. The method developed uses an exponentially weighted moving average (EWMA) control chart. Comparison of the EWMA with previously used FR onset methods, namely the discrete (n), mean (n (raised bar)), normalized (n%) and normalized mean (n(raised bar)%) methods, revealed the EWMA method yields more consistently linear FR versus load relationships between specimens. Other findings include a correlation between AE data richness and FR linearity based on the FR methods discussed in this paper, and evidence of premature failure at lower than expected loads. Application of the EWMA method should be extended to other composite materials and, eventually, composite components such as composite overwrapped pressure vessels. Furthermore, future experiments should attempt to uncover the factors responsible for infant mortality in C/Ep strands
Additive Manufactured Product Integrity
NASA is providing key leadership in an international effort linking NASA and non-NASA resources to speed adoption of additive manufacturing (AM) to meet NASA's mission goals. Participants include industry, NASA's space partners, other government agencies, standards organizations and academia. Nondestructive Evaluation (NDE) is identified as a universal need for all aspects of additive manufacturing
Durrington Walls to West Amesbury by way of Stonehenge: a major transformation of the Holocene landscape
A new sequence of Holocene landscape change has been discovered through an investigation of sediment sequences, palaeosols, pollen and molluscan data discovered during the Stonehenge Riverside Project. The early post-glacial vegetational succession in the Avon valley at Durrington Walls was apparently slow and partial, with intermittent woodland modification and the opening-up of this landscape in the later Mesolithic and earlier Neolithic, though a strong element of pine lingered into the third millennium BC. There appears to have been a major hiatus around 2900 cal BC, coincident with the beginnings of demonstrable human activities at Durrington Walls, but slightly after activity started at Stonehenge. This was reflected in episodic increases in channel sedimentation and tree and shrub clearance, leading to a more open downland, with greater indications of anthropogenic activity, and an increasingly wet floodplain with sedges and alder along the riverâs edge. Nonetheless, a localized woodland cover remained in the vicinity of DurringtonWalls throughout the third and second millennia BC, perhaps on the higher parts of the downs, while stable grassland, with rendzina soils, predominated on the downland slopes, and alderâhazel carr woodland and sedges continued to fringe the wet floodplain. This evidence is strongly indicative of a stable and managed landscape in Neolithic and Bronze Age times. It is not until c 800â500 cal BC that this landscape was completely cleared, except for the marshy-sedge fringe of the floodplain, and that colluvial sedimentation began in earnest associated with increased arable agriculture, a situation that continued through Roman and historic times
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