A Comparison of Energy Conversion Technologies for Space Nuclear Power Systems

A key element of space nuclear power systems is the energy conversion subsystem that converts the nuclear heat into electrical power. Nuclear systems provide a favorable option for missions that require long-duration power in hostile space environments where sunlight for solar power is absent or limited. There are two primary nuclear power technology options. Radioisotope Power System (RPS) utilize the natural decay heat from Pu238 to generate electric power levels up to about one kilowatt. Fission Power System (FPS) rely on a sustained fission reaction of U235 and offer the potential to supply electric power from kilowatts to megawatts. Example missions for nuclear power include Mars science rovers (e.g. Curiosity, Mars 2020), lunar and Mars surface landers ? including crewed missions, deep space planetary orbiters, Ocean World science landers, and robotic space probes that utilize nuclear electric propulsion. This paper examines the energy conversion technology options that can be used with RPS and FPS, and provides an assessment of their relative performance and technology readiness

Investigation of Exoskeletal Engine Propulsion System Concept

An innovative approach to gas turbine design involves mounting compressor and turbine blades to an outer rotating shell. Designated the exoskeletal engine, compression (preferable to tension for high-temperature ceramic materials, generally) becomes the dominant blade force. Exoskeletal engine feasibility lies in the structural and mechanical design (as opposed to cycle or aerothermodynamic design), so this study focused on the development and assessment of a structural-mechanical exoskeletal concept using the Rolls-Royce AE3007 regional airliner all-axial turbofan as a baseline. The effort was further limited to the definition of an exoskeletal high-pressure spool concept, where the major structural and thermal challenges are represented. The mass of the high-pressure spool was calculated and compared with the mass of AE3007 engine components. It was found that the exoskeletal engine rotating components can be significantly lighter than the rotating components of a conventional engine. However, bearing technology development is required, since the mass of existing bearing systems would exceed rotating machinery mass savings. It is recommended that once bearing technology is sufficiently advanced, a "clean sheet" preliminary design of an exoskeletal system be accomplished to better quantify the potential for the exoskeletal concept to deliver benefits in mass, structural efficiency, and cycle design flexibility

What do people do with porn? qualitative research into the consumption, use and experience of pornography and other sexually explicit media

This article reviews qualitative research into the consumption of pornography and other sexually explicit media emerging from a range of subject areas. Taking a critique of quantitative methods and a focus on measuring sexual effects and attitudes as a starting point, it considers the proposition that qualitative work is more suited to an examination of the complex social, cultural and political constructions of sexuality. Examining studies into the way men, women and young people see, experience, and use explicit media texts, the article identifies the key findings that have emerged. Qualitative work shows that sexuality explicit media texts are experienced and understood in a variety of ways and evoke strong and often contradictory reactions, not all of which are represented in public debates about pornography. These texts function in a range of different ways, depending on context; as a source of knowledge, a resource for intimate practices, a site for identity construction, and an occasion for performing gender and sexuality. The article reviews these studies and their findings, identifying what they suggest about directions for future research, both in terms of developing methodology and refining approaches to sexuality and media consumption.</p

MACE and VTE across upadacitinib clinical trial programmes in rheumatoid arthritis, psoriatic arthritis and ankylosing spondylitis

Objectives To provide an integrated analysis of major adverse cardiovascular events (MACEs) and events of venous thromboembolism (VTE) and associated risk factors across rheumatoid arthritis (RA), psoriatic arthritis (PsA), and ankylosing spondylitis (AS) phase 2b/3 upadacitinib clinical programmes. Methods Data were analysed and summarised from clinical trials of RA, PsA and AS treated with upadacitinib 15 mg once daily (QD) and 30 mg QD (as of 30 June 2021). Data from adalimumab (RA and PsA) and methotrexate (RA) arms were included as comparators. Adjudicated MACEs and VTE events were presented as exposure-adjusted rates per 100 patient-years (E/100 PY). Univariable Cox proportional hazard regression analyses assessed potential associations of risk factors for MACE and VTE. Results In total, 4298 patients received upadacitinib 15 mg (RA n=3209, PsA n=907 and AS n=182) and 2125 patients received upadacitinib 30 mg (RA n=1204 and PsA n=921). In patients with RA and PsA, rates of MACE (0.3–0.6 E/100 PY) and VTE (0.2–0.4 E/100 PY) were similar across upadacitinib doses; in patients with AS, no MACEs and one VTE event occurred. Most patients experiencing MACEs or VTE events had two or more baseline cardiovascular risk factors. Across RA and PsA groups, rates of MACEs and VTE events were similar. Conclusions Rates of MACEs and VTE events with upadacitinib were consistent with previously reported data for patients receiving conventional synthetic and biologic disease-modifying anti-rheumatic drugs and comparable with active comparators adalimumab and methotrexate. Associated patient characteristics are known risk factors for MACEs and VTE events

Performance Evaluation of the NASA GTX RBCC Flowpath

The NASA Glenn Research Center serves as NASAs lead center for aeropropulsion. Several programs are underway to explore revolutionary airbreathing propulsion systems in response to the challenge of reducing the cost of space transportation. Concepts being investigated include rocket-based combined cycle (RBCC), pulse detonation wave, and turbine-based combined cycle (TBCC) engines. The GTX concept is a vertical launched, horizontal landing, single stage to orbit (SSTO) vehicle utilizing RBCC engines. The propulsion pod has a nearly half-axisymmetric flowpath that incorporates a rocket and ram-scramjet. The engine system operates from lift-off up to above Mach 10, at which point the airbreathing engine flowpath is closed off, and the rocket alone powers the vehicle to orbit. The paper presents an overview of the research efforts supporting the development of this RBCC propulsion system. The experimental efforts of this program consist of a series of test rigs. Each rig is focused on development and optimization of the flowpath over a specific operating mode of the engine. These rigs collectively establish propulsion system performance over all modes of operation, therefore, covering the entire speed range. Computational Fluid Mechanics (CFD) analysis is an important element of the GTX propulsion system development and validation. These efforts guide experiments and flowpath design, provide insight into experimental data, and extend results to conditions and scales not achievable in ground test facilities. Some examples of important CFD results are presented

Perceived efficacy of evidence-based and non-evidence-based self-treatments for managing chronic concussion symptoms

Objectives: The purpose of this study was to assess history of self-treatment to persistent concussive symptoms and perceived efficacy of well-established and non-validated approaches to alleviating post-concussive symptoms among former and current athletes. It was hypothesized that participants with chronic repeated incidences of concussions would attempt more approaches to treatment not advocated for by mainstream sports medicine organizations and that perceived efficacy of some under-researched treatments would be comparable to highly supported, evidence-based approaches. Design: Observational, cross-sectional, online survey using Qualtrics XM. Participants: 977 college students (18+) were recruited at a central Illinois university. Outcome Measures: Concussion history, duration of postconcussive symptoms, treatment experience (types, duration, and perceived effectiveness), and subjective cognitive functioning were assessed. Results: Among respondents, 219 (22.4%) reported a history of at least one concussion with 59 (26.7%) reporting concussive symptoms lasting &gt;1 month. The most common treatment sought was mild physical activity (57.1%) followed by cryotherapy (42.9%) and moderate physical activity (42.9%). The same three treatments (in ranked-order) were perceived to be at least somewhat effective for reducing symptoms (94.7%, 92.9%, and 91.9%, respectively). Results also supported hypothesized patterns reflecting less favorable perceptions of memory and mindful attention among those with one or more concussions (relative to those with none). Total treatments sought was associated with higher anxiety, depression, and memory ability. Conclusion: These findings support prior research on the cognitive effects of concussion and offer insight into the potential efficacy of various treatments for improving concussion-related symptoms