Precision heat forming of tetrafluoroethylene tubing

An invention that provides a method of altering the size of tetrafluoroethylene tubing which is only available in limited combination of wall thicknesses and diameter are discussed. The method includes the steps of sliding the tetrafluoroethylene tubing onto an aluminum mandrel and clamping the ends of the tubing to the mandrel by means of clamps. The tetrafluorethylene tubing and mandrel are then placed in a supporting coil which with the mandrel and tetrafluorethylene tubing are then positioned in a insulated steel pipe which is normally covered with a fiber glass insulator to smooth out temperature distribution therein. The entire structure is then placed in an event which heats the tetrafluorethylene tubing which is then shrunk by the heat to the outer dimension of the aluminum mandrel. After cooling the aluminum mandrel is removed from the newly sized tetrafluorethylene tubing by a conventional chemical milling process

Balanced and Imbalanced Societal Norms About Working: A Comparison of Four National Labor Markets at Two Time Points

Two normative orientations: work as an obligation/duty versus work as an entitlement/right are compared among representative samples from the American, German, Belgian, and Japanese labor force exploring four domains: Work itself\u27, Meaningful work , Work Improvements , and Care for the Future at two points in time. Results reveal: Stability over time, and significant differences related to age, occupational group membership, and country

How Working is Defined: Structure and Stability

[Excerpt] Multidimensional scaling of statements that identify when individuals consider an activity in which one is engaged to be working was conducted on representative samples of the employed labor forces in Belgium, Germany, Japan and the USA at the time period 1982-83 and again at the time period 1989-92. Representative labor force samples of the employed labor forces in East Germany, Bulgaria, the Czech Republic, Hungary, Poland, Slovakia and Beijing, China studied at the time period 1991-92 were subjected to the same MDS analysis. The results provide strong support that one dominant dimension underlying the way in which people define working ranges from individual cost to social contribution. Individuals who define working in burden and/or constraint terms emphasize costs to the individual. Individuals who define working largely in responsibility and exchange terms emphasize reciprocal exchange relations between the individual and the organization/society. Individuals who define working largely in social contribution terms emphasize the social benefits of working. The work definition structures found in each of the four countries with replication samples are quite stable over time. In total, the work definition responses of over 18,000 individuals were studied

Atypical Thermonuclear Supernovae from Tidally Crushed White Dwarfs

Suggestive evidence has accumulated that intermediate mass black holes (IMBH) exist in some globular clusters. As stars diffuse in the cluster, some will inevitable wander sufficiently close to the hole that they suffer tidal disruption. An attractive feature of the IMBH hypothesis is its potential to disrupt not only solar-type stars but also compact white dwarf stars. Attention is given to the fate of white dwarfs that approach the hole close enough to be disrupted and compressed to such extent that explosive nuclear burning may be triggered. Precise modeling of the dynamics of the encounter coupled with a nuclear network allow for a realistic determination of the explosive energy release, and it is argued that ignition is a natural outcome for white dwarfs of all varieties passing well within the tidal radius. Although event rates are estimated to be significantly less than the rate of normal Type Ia supernovae, such encounters may be frequent enough in globular clusters harboring an IMBH to warrant a search for this new class of supernova.Comment: 13 pages, 4 figures, ApJ, accepte

Vortex-enhanced propulsion

It has been previously suggested that the generation of coherent vortical structures in the near-wake of a self-propelled vehicle can improve its propulsive efficiency by manipulating the local pressure field and entrainment kinematics. This paper investigates these unsteady mechanisms analytically and in experiments. A self-propelled underwater vehicle is designed with the capability to operate using either steady-jet propulsion or a pulsed-jet mode that features the roll-up of large-scale vortex rings in the near-wake. The flow field is characterized by using a combination of planar laser-induced fluorescence, laser Doppler velocimetry and digital particle-image velocimetry. These tools enable measurement of vortex dynamics and entrainment during propulsion. The concept of vortex added-mass is used to deduce the local pressure field at the jet exit as a function of the shape and motion of the forming vortex rings. The propulsive efficiency of the vehicle is computed with the aid of towing experiments to quantify hydrodynamic drag. Finally, the overall vehicle efficiency is determined by monitoring the electrical power consumed by the vehicle in steady and unsteady propulsion modes. This measurement identifies conditions under which the power required to create flow unsteadiness is offset by the improved vehicle efficiency. The experiments demonstrate that substantial increases in propulsive efficiency, over 50 % greater than the performance of the steady-jet mode, can be achieved by using vortex formation to manipulate the near-wake properties. At higher vehicle speeds, the enhanced performance is sufficient to offset the energy cost of generating flow unsteadiness. An analytical model explains this enhanced performance in terms of the vortex added-mass and entrainment. The results suggest a potential mechanism to further enhance the performance of existing engineered propulsion systems. In addition, the analytical methods described here can be extended to examine more complex propulsion systems such as those of swimming and flying animals, for whom vortex formation is inevitable

Invariance of the Cuntz splice

We show that the Cuntz splice induces stably isomorphic graph $C^*$-algebras.Comment: Our arguments to prove invariance of the Cuntz splice for unital graph C*-algebras in arXiv:1505.06773 applied with only minor changes in the general case. Since most of the results of that preprint have since been superseded by other forthcoming work, we do not intend to publish it, whereas this work is intended for publication. arXiv admin note: substantial text overlap with arXiv:1505.0677

User Guide: A Guide to Disability Statistics from the National Assessment of Educational Programs (NAEP)

Policymakers, service providers, disability advocacy groups and researchers use disability statistics for a wide variety of purposes. A common problem that these groups encounter is finding a data source, a disability definition and/or a statistical method that provides them with a disability statistic that is both relevant to their needs and useful. The mission of the Cornell StatsRRTC is to bridge the divide between the sources of disability data and the users of disability statistics. One product of this effort is a series of User Guides to national survey data sets that collect information on the disability population. The purpose of each of the User Guides is to provide disability data users with: 1. An easily accessible guide to the disability information available in the nationally representative survey; 2. Estimates of the population with a disability, the disability prevalence rate, and estimates of participation-related statistics; 3. A description of the unique features of the dataset that will help disability statistics users determine whether the dataset can provide them with the statistic that they need; and 4. A description of how the dataset compares to other national data that are used to describe the population with disabilities. This User Guide contains information on the National Assessment of Educational Programs (NAEP), also known as “the Nation\u27s Report Card.” Unlike the other data sources addressed by the User Guide Series, the NAEP focuses solely on children. As a result, the focus of this Guide will shift to the inclusion and accommodation of educational activities of children with disabilities, as opposed to adult employment and economic well-being, which are the focus of many of the other User Guide