Advanced Flywheel Technology for Space Applications

For spacecraft applications, energy storage sources are required to produce a high yield with minimum size and mass. Flywheel systems have the potential to fill this need while also providing attitude control for the guidance of the craft. Other advantages include on-board peak power management, extended service life (as compared to chemical batteries), and provisions for redundant systems with minimum effect on the projected payload of the craft. This paper reviews the results of flywheel design projects carried out at The University of Texas at Austin Center for Electromechanics (UT-CEM), discusses the role of composites in design development, and presents a detailed discussion of a flywheel design currently under study.Center for Electromechanic

Light-Weight Containment for High Energy, Rotating Machines

Developed a lightweight containment system for high-speed composite rotors. The containment device, consisting of a rotatable, composite structure, has been demonstrated to contain the high-energy release from a rotor burst event and is applicable to composite rotors for pulsed power applications. The most important aspect of this design is that the free-floating containment structure dissipates the major loads (radial, torque, and axial) encountered during the burst event, greatly reducing the loads that pass through the stator structure to its attachments. The design results in significant system-level weight savings for the entire rotating machine when compared to a system with an all-metallic containment. Of equal interest to the containment design, the experimental design and instrumentation was very challenging and resulted in significant lessons learned. This paper describes the containment system design, rotor burst test setup, instrumentation for measuring loads induced by the burst event, and a detailed explanation of the successful containment test results and conclusions.Center for Electromechanic

The triple-pomeron regime and the structure function of the pomeron in the diffractive deep inelastic scattering at very small x

Misprints and numerical coefficients corrected, a bit of phenomenology and one figure added. The case for the linear evolution of the unitarized structure functions made stronger.Comment: KFA-IKP(Th)-1993-17, Landau-16/93, 46 pages, 14 figures upon request from N.Nikolaev, [email protected]

Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362

Hydroburst Test Methodology for Evaluation of Composite Structures

The University of Texas at Austin Center for Electromechanics (UT-CEM) is under contract to develop high-speed composite flywheel systems for a number of energy and power averaging applications in the transportation and space industries. Safe and reliable design of composite flywheels requires well-characterized material properties. Efforts have been focused on design optimization of a hydroburst test technique that demonstrates a useful method for characterizing the hoop (circumferential) properties of filament wound composite rings, and those results are then available to predict the performance of full-scale flywheels. To demonstrate the usefulness of this method, this paper discusses typical hydroburst techniques to determine material properties for filament-wound composite rings. Test results are also presented. Seal design is a key element of this fixture, and a design has evolved that provides nearly uniform radial loading on the inside surface of the composite ring, while minimizing axial bending. Correlations of tow strand data with hydroburst lamina data are presented. Also discussed are hydroburst test applications for flaw assessment and fatigue property evaluation.Center for Electromechanic

Hydroburst testing for filament wound composites

Center for Electromechanic

Test Methods for Composite Structures for Pulsed Power, Rotating Machines

Composites are an enabling technology for achieving high power and energy densities in pulsed power rotating machinery. Due to extreme thermomechanical loads, an optimized combination of structural, thermal, and electrical properties is required to achieve the desired durability and service life performance. Coupon level tests are performed to generate the results necessary to quantify these properties and guide the development of a correctly balanced composite. This paper presents a top-level discussion of test methodologies and their use that are important for evaluation of composite laminate properties for pulsed power applications. Test methodologies include: (1) hydroburst for hoop (circumferential) properties; (2) transverse tensile and shear tests for resin dominated loading; (3) radial precompression testing for viscoelastic effects; (4) fiber digestion for fiber volume and void content determination, digital photomicrographs for visual evaluation; and (5) transverse electrical conductivity tests. Both the hydroburst and transverse tensile test fixtures feature elevated temperature test capabilities. These test techniques, which are currently in use at The University of Texas at Austin Center for Electromechanics (UT-CEM), are described and typical test-generated data is discussed.Center for Electromechanic