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

The efficacy of an aerobic exercise and cognitive training program on postconcussion symptomology

A concussion is a type of mild traumatic brain injury (mTBI) resulting from a bump, blow, or jolt to the head or body that causes rapid movement of the head and brain. A neurometabolic crisis results, causing an ionic flux and the release of glutamate to resolve the injured brain’s energy demands. In the majority of cases, individuals make a full recovery as the byproduct of cognitive and physical rest. When individuals do not return to normal levels of functioning, chronic cell death, neuronal dysfunction, and neurodegeneration may underlie long-term impairment (>1 month). Postconcussion syndrome (PCS) refers to the collection of lingering symptoms that follows concussion. PCS has become a major public health concern due to its increasing prevalence and lack of consensus regarding a scientifically valid treatment protocol. Symptoms such as headache, difficulty concentrating, and depressed mood may continue for weeks, months, and even years after the injury. Despite evidence of cognitive and affective benefits of physical activity, individuals with lingering symptoms are often reluctant to engage in exercise for fear of symptom exacerbation. However, recent scientific evidence has supported engagement in aerobic exercise to reduce symptom severity. In addition to aerobic exercise, cognitive training is a tool often used to improve cognitive deficits. Relying on brain plasticity-based learning, cognitive training targets specific cognitive abilities such as attentional control that may translate into a reduction of PCS symptoms. To date, no studies have tested the combined effects of aerobic exercise and cognitive training on refractory postconcussion symptom reduction. The purpose of this study was to examine the efficacy of a multimodal, center and home-based training program involving aerobic exercise and cognitive training on symptom reduction among individuals with refractory symptoms of concussion, mTBI, or other head injury. Participants were randomized to one of three conditions: (1) an aerobic exercise and cognitive training group, (2) an aerobic exercise and video watching group, or (3) a control group. Results of a repeated measures analysis of covariance indicated statistically significant within-group effects [F(2,26) = 6.54, p < .05, d = .72] and between-group effects [F(2,26) = 4.90, p < .05, d = .56] on RPQ-3 ratings as well as within- [F(2,26) = 10.36, p < .05, d = .90] and between-group effects [F(2,26) = 5.51, p < .05, d = .88] on RPQ-13 ratings. Cognition was assessed using assessments from the NIH Toolbox Cognitive Battery. Significant differences on measures of inhibitory control and attention, working memory, processing speed, and executive switching are discussed. Results should be interpreted with caution due to the preliminary nature of the study. Findings can be used to guide future research design and intervention that incorporate multiple approaches for the treatment of PCS.U of I OnlyAuthor requested U of Illinois access only (OA after 2yrs) in Vireo ETD syste

Structural Sizing of a 25,000-lb Payload, Air-Breathing Launch Vehicle For Single-Stage-To-Orbit

In support of NASA's Air-Breathing Launch Vehicle (ABLV) study, a 25,000-lb payload version of the GTX (formerly Trailblazer) reference vehicle concept was developed. The GTX is a vertical lift-off, reusable, single-stage-to-orbit launch vehicle concept that uses hypersonic air-breathing propulsion in a rocket-based combined-cycle (RBCC) propulsion system to reduce the required propellant fraction. To achieve this goal the vehicle and propulsion system must be well integrated both aerodynamically and structurally to reduce weight. This study demonstrates the volumetric and structural efficiency of a vertical takeoff, horizontal landing, hypersonic vehicle with a circular cross section. A departure from the lifting body concepts, this design philosophy is even extended to the engines, which have semicircular nacelles symmetrically mounted on the vehicle. Material candidates with a potential for lightweight and simplicity have been selected from a set of near term technologies (5 to 10 years). To achieve the mission trajectory, preliminary weight estimates show the vehicle's gross lift-off weight is 1.26 x 10(exp 6) lb. The structural configuration of the GTX vehicle and its propulsion system are described. The vehicle design benefits are presented, and key technical issues are highlighted

Effects of Traditional vs. iPad-Enhanced Aerobic Exercise on Wayfinding Efficacy and Cognition: A Pilot Randomized Controlled Trial

The purpose of this pilot study was to test the feasibility and efficacy of an iPad-enhanced aerobic exercise intervention designed to enhance wayfinding efficacy and performance and relevant cognitive functioning among middle-aged adults at risk for cognitive impairment. Twenty-seven low active adults (21 females) aged 45 to 62 years (51.22 &plusmn; 5.20) participated in a ten-week randomized controlled trial. Participants were randomized to an iPad-enhanced aerobic exercise group (experimental group) or an aerobic exercise-only group (control group) following baseline assessment. Both groups exercised at 50% to 75% of age-predicted heart rate maximum for 30 to 50 min/d, 2 d/wk for 10 weeks. During aerobic exercise, the experimental group engaged in virtual tours delivered via iPad. Baseline and post-intervention assessments of wayfinding self-efficacy, wayfinding task performance, cognitive functioning, electroencephalogram (EEG), and psychosocial questionnaires were administered. The results suggest that ten weeks of iPad-enhanced, moderately intense aerobic exercise had specific effects on wayfinding self-efficacy; however, no statistical differences were found between groups on the behavioral wayfinding task or spatial memory performance at follow-up. Performance scores on an inhibitory attentional-control cognitive assessment revealed significant differences between groups, favoring the experimental group (p &lt; 0.05). Virtual reality-enhanced aerobic exercise may prove to be an effective method for improving cognitive function and increasing confidence to navigate real-world scenarios among individuals at risk of cognitive impairment

Association Between the 7-Day Moving Average for Nutrition and Growth in Very Low Birth Weight Infants.

BACKGROUND: Very low birth weight (VLBW) infants remain at risk for postnatal growth restriction. Clinicians may have difficulty identifying growth patterns resulting from nutrition interventions, impeding prompt management changes intended to increase growth velocity. This study aimed to quantify the association between growth and nutrition intake through 7-day moving averages (SDMAs). METHODS: The first 6 weeks of daily nutrition intake and growth measurements were collected from VLBW infants admitted to a level 4 neonatal intensive care unit (2011-2014). The association between SDMA for energy and macronutrients and subsequent 7-day growth velocities for weight, length, and head circumference were determined using mixed effects linear regression. Analyses were adjusted for fluid intake, infant characteristics, and comorbid conditions. RESULTS: Detailed enteral and parenteral caloric provisions were ascertained for 115 infants (n = 4643 patient-days). Each 10-kcal/kg/d increase over 7 days was independently associated with increased weight (1.7 g/kg/d), length (0.4 mm/wk), and head circumference (0.9 mm/wk; P \u3c .001, for weight and head circumference; P = .041 for length). Each 1 g/kg/d macronutrient increase was also associated with increased weight (protein, P = .027; fat and carbohydrates, P \u3c .001), increased length (fat, P = .032), and increased head circumference (fat and carbohydrates, P \u3c .001). CONCLUSIONS: The SDMA identifies clinically meaningful associations among total energy, macronutrient dosing, and growth in VLBW infants. Whether SDMA is a clinically useful tool for providing clinicians with prompt feedback to improve growth warrants further attention