Background: The human ability to adapt to extreme environments is fascinating. Research into this adaptation has been lacking in Arctic isolated teams because it has concentrated on Antarctic teams. The hazards of the poles often confine the researchers indoors with their colleagues, reducing their privacy. This deployment also limits their contact with loved ones at home. Subsequently, over the course of polar night, rates of anxiety, depression, irritability and sleep disturbance increase (Suedfeld & Palinkas, 2008). Often, the teams complain of cognitive impairments. The High Arctic’s distinctive feature is the polar bear. The presence of bears requires Arctic research station teams to handle fire arms for their personal safety. It also means that fire arms – which are highly restricted in the Antarctic – are ever-present and easily accessible at Arctic stations. This poses a unique psychological challenge for these teams which has not been well-researched. Methodology: This thesis is an original contribution to science in that it employs a mixed-methods approach combining phenomenological interviews, cognitive testing and mental health assessment via questionnaires with a team spending a year at the Polish Polar Station, Hornsund, Svalbard. The participants were ten of the eleven winter team members who spent the year between July 2015 and June 2016 at Hornsund (“Explorers”) and an age-/gender-/education-matched control group (“Controls”). They filled in the Symptom Checklist-90-Revised and the Profile of Mood States-Brief Version in July, September, January, April and June of that year. Cognitive testing was completed in September, January and June; it comprised the Figural Learning and Memory Test, the Sustained Attention to Response Task (SART), the elevator tasks of the Test of Everyday Attention (TEA) and the Raven Standard Progressive Matrices. The interviews took place at the same time as the cognitive testing. Results: The results showed that the most stressful time reported in the questionnaires was April 2016, just after the winter isolation had ended and the sun had risen again. The Explorers reported little subjective complaints about their cognition but they performed near-ceiling on the TEA while scoring far below their Controls on the SART. This implies a dichotomy between sustained attention and inhibition in the Explorers. Their lived experiences were shaped by a struggle to adapt to the other team members rather than by struggling to adapt to the hazardous environment. The environment was perceived as awe-inspiring. Over time, the Explorers shifted their view of the team from informal colleagues to a family which they did not choose to be a member of and then, to friends. Unanimously, other people were seen as the most difficult aspect of the mission. Conclusions: This thesis provides unique insight into a non-Anglo-Saxon Arctic wintering team: the conclusions suggest that participants should receive social training to get along better and be emotionally prepared. The findings can be implemented by my research partner, the Institute of Geophysics (Warsaw) to better select and prepare their future expeditions to Hornsund. Some of the insights such as the nature of the interpersonal stressors may be applicable to space missions.

The environmental and psychosocial adversity inherent in remote polar locales has historically been framed in pathological terms. However, a burgeoning body of evidence suggests that stressful conditions across isolated, confined, and extreme (ICE) environments may elicit positive growth outcomes as well. The purpose of this cross-sectional, retrospective study was to assess the incidence and correlates of PostExpedition Growth (PEG) in returned Antarctic expeditioners. The prevalence of five specific personal growth indicators – ‘new opportunities,’ ‘relating to others,’ ‘personal strength,’ ‘spiritual change,’ and ‘appreciation of life’ – along with individual and group variables that have been associated with growth in trauma-exposed populations (i.e., coping, mindfulness, personality traits, personal value priorities, adverse childhood experiences, and expedition/experience specific variables) were examined using a mixed methods approach. Quantitative results indicate a moderate, positive association between proactive coping and appreciation of life, as well as between universalism (i.e., a sense of harmony or oneness with humanity and the natural world), new possibilities, and appreciation of life. Qualitative findings provide a more nuanced understanding of the five dimensions of PEG and underscore the emergence of a sixth dimension, an enhanced relationship with nature. Further research is needed to illuminate knowledge gaps in ICE environment research, and to help identify potential countermeasures for individuals and groups faced with comparable adversity factors in their immediate environments (i.e., within the current context of COVID-19). A deeper understanding of PEG in ICE environments – as well as promotive factors that strengthen positive outcomes – will serve to inform the development of countermeasures to mitigate health and wellbeing risks following exposure to isolation and confinement in extreme environments. / Graduate / 2022-09-29

No description available.

No / Scytonemin-imine, a novel derivative of scytonemin, has been isolated and identified very recently and proposed to serve as a photoprotective biomarker for certain bacteria growing under intense photon flux density. This study predicts theoretically the Raman spectrum of scytonemin-imine by density functional theory calculations and provides comparison of major bands to those of scytonemin, the parent compound for which both the experimentally characterized and theoretically predicted spectra exist in the literature. It is proposed to be an addendum to the collection of our previous work on scytonamin and its derivatives to facilitate recognition of the diagnostic Raman spectral signatures for scytonemin-imine.

No description available.

A background investigation of the total-dose radiation tolerance of a third generation complementary SiGe:C BiCMOS technology platform was performed. Tolerance was quantified under proton and X-ray radiation sources for both the npn and pnp HBT, as well as for an operational amplifier built with these devices. Furthermore, a technique known as junction isolation radiation hardening was proposed and tested with the goal of improving the SEE sensitivity of the npn by reducing the charge collected by the subcollector in the event of a direct ion strike. Three independent systems were designed, including: 1) a charge amplification channel developed as part of a remote electronics unit for the lunar environment, 2) variable bias circuitry for a self-healing radar receiver, and 3) an ultra-fast x-ray detector for picosecond scale time-domain measurements of evolving chemical reactions. The first two projects capitalized on the wide-temperature performance and radiation tolerance of the SiGe HBT, allowing them to operate under extreme environmental conditions reliably and consistently. The third design makes use of the high-frequency capabilities of the HBT, particularly in emitter-coupled logic (ECL) configurations. Findings concerning the performance of these systems and implications for future research are discussed.

Extreme environments pose major obstacles for electronics in the form of extremely wide temperature ranges and hazardous radiation. The most common mitigation procedures involve extensive shielding and temperature control or complete displacement from the environment with high costs in weight, power, volume, and performance. There has been a shift away from these solutions and towards distributed, in-environment electronic systems. However, for this methodology to be viable, the requirements of heavy radiation shielding and temperature control have to be lessened or eliminated. This work gained new understanding of the best practices in analog circuit design for extreme environments. Major accomplishments included the over-temperature -180 C to +120 C and radiation validation of the SiGe Remote Electronics Unit, a first of its kind, 16 channel, sensor interface for unshielded operation in the Lunar environment, the design of two wide-temperature (-180 C to +120 C), total-ionizing-dose hardened, wireline transceivers for the Lunar environment, the low-frequency-noise characterization of a second-generation BiCMOS process from 300 K down to 90 K, the explanation of the physical mechanisms behind the single-event transient response of cascode structures in a 45 nm, SOI, radio-frequency, CMOS technology, the analysis of the single-event transient response of differential structures in a 32 nm, SOI, RF, CMOS technology, and the prediction of scaling trends of single-event effects in SOI CMOS technologies.

This dissertation presents an investigation of miniaturized sensors, designed to wirelessly measure pressure in harsh environments such as high temperature and biomedical applications. Current wireless MEMS pressure sensors are silicon-based and have limited high temperature operation, require internal power sources, or have limited packaging technology that restricts their use in harsh environments. Sensor designs in this work are based on passive LC resonant circuits to achieve wireless telemetry without the need for active circuitry or internal power sources. A cavity, which is embedded into the substrate, is bound by two pressure-deformable plates that include a parallel-plate capacitor. Deflection of the plates from applied pressure changes the capacitance, thus the resonance frequency varies and is a function of the applied pressure. The LC resonant circuit and pressure-deformable plates are fabricated into a monolithic housing that servers as the final device package (i.e. intrinsically packaged). This co-integration of device and package offers increased robustness and the ability to operate wirelessly in harsh environments. To intrinsically packaged devices, the fabrication approach relies on techniques developed for MEMS and leverage established lamination-based manufacturing processes, such as ceramic and flex-circuit packaging technologies. To demonstrate operation in high temperatures applications, LTCC and HTCC ceramic pressure sensors were fabricated and characterized, operating up to 450°C under 5 bars of pressure while HTCC devices demonstrated electrical functionality up to 600°C. To demonstrate operation in biomedical implantable applications, polymer-based and polymer-ceramic flexible designs were fabricated and characterized. Bench testing for > 300 millions pressure cycles (simulated 7 years of pulse pressure) confirmed the reduction of frequency drift for polymer-ceramic pressure sensors compared to purely polymer-based pressure sensors. Finally, LCP-based pressure sensors were delivered in vivo into canine models with mock abdominal aortic aneurysms and monitored wirelessly over 30 days. The animal results confirmed both catheter deliverability and wireless telemetry in real biomedical applications.

This thesis describes the architecture, verification, qualification, and packaging of a 16-channel silicon-germanium (SiGe) Remote Electronics Unit (REU) designed for use in extreme environment applications encountered on NASA's exploration roadmap. The SiGe REU was targeted for operation outside the protective electronic "vaults" in a lunar environment that exhibits cyclic temperature swings from -180ºC to 120ºC, a total ionizing dose (TID) radiation level of 100 krad, and heavy ion exposure (single event effects) over the mission lifetime. The REU leverages SiGe BiCMOS technological advantages and design methodologies, enabling exceptional extreme environment robustness. It utilizes a mixed-signal Remote Sensor Interface (RSI) ASIC and an HDL-based Remote Digital Control (RDC) architecture to read data from up to 16 sensors using three different analog channel types with customizable gain, current stimulus, calibration, and sample rate with 12-bit analog-to-digital conversion. The SiGe REU exhibits excellent channel sensitivity throughout the temperature range, hardness to at least 100 krad TID exposure, and single event latchup immunity, representing the cutting edge in cold-capable electronic systems. The SiGe REU is the first example within a potential paradigm shift in space-based electronics.

Ultra-high temperature (i.e., greater than 2500°C) engineering applications present continued materials challenges. Refractory metal/ceramic composites have great potential to satisfy the demands of extreme environments (e.g., the environments found in solid rocket motors upon ignition), though general scalable processing techniques to fabricate complex shaped parts are lacking. The work embodied in this dissertation advances scientific knowledge in the development of processing techniques to form complex, near net-shape, near net-dimension, near fully-dense refractory metal/ceramic composites with controlled phase contents and microstructure. Three research thrusts are detailed in this document. First, the utilization of rapid prototyping techniques, such as computer numerical controlled machining and three dimensional printing, for the fabrication of porous tungsten carbide preforms and their application with the Displacive Compensation of Porosity process is demonstrated. Second, carbon substrates and preforms have been reactively converted to porous tungsten/tungsten carbide replicas via a novel gas-solid displacement reaction. Lastly, non-oxide ceramic solid solutions have been internally reduced to create intragranular metal/ceramic micro/nanocomposites. All three techniques combined have the potential to produce nanostructured refractory metal/ceramic composite materials with tailorable microstructure for ultra-high temperature applications.