Apparatus for reducing aerodynamic noise in a wind tunnel

An apparatus is described for reducing the background noise produced by the porous walls of the test section of a wind tunnel. A finely meshed screen member is placed over the perforations in the test section walls. The mesh wire screen attached to the interior wall provides a smoother surface for the air stream to flow against reducing the vorticies produced by the edges of the perforations in the test section walls

Calculation of the inertia tensor and center of gravity of complex bodies

Inertia tensor is calculated for each component part of a body about its own principal axes, and then with respect to the body's reference axes /rotation/. All parts are then combined to calculate the center of gravity and inertia tensor of the body

Merger Policy and Innovation: Must Enforcement Change to Account for Technological Change?

Merger policy is the most active area of U.S. antitrust policy. It is now widely believed that merger policy must move beyond its traditional focus on static efficiency to account for innovation and address dynamic efficiency. Innovation can fundamentally affect merger analysis in two ways. First, innovation can dramatically affect the relationship between the pre-merger marketplace and what is likely to happen if a proposed merger is consummated. Thus, innovation can fundamentally influence the appropriate analysis for addressing traditional, static efficiency concerns. Second, innovation can itself be an important dimension of market performance that is potentially affected by a merger. We explore how merger policy is meeting the challenges posed by innovation.

The intersection of race, sexual orientation, socioeconomic status, trans identity, and mental health outcomes

The present study examined patterns in trans individuals’ multiple identities and mental health outcomes. Cluster 1 (socioeconomic and racial privilege; n = 239) was characterized by individuals who identified as trans women or cross-dressers, lesbian, bisexual, or questioning; had associates degrees; reported household incomes of $60,000 or more a year; and were non-Latino White. Cluster 2 (educational privilege; n = 191) was characterized by individuals who identified as trans men or genderqueer, gay, or queer; had a bachelor’s degree; reported household incomes of$10,000 or less a year; and were people of color. There was a pattern of individuals in Cluster 1 who identified with two privileged identities (identifying as White and having higher household incomes), whereas individuals in Cluster 2 identified only formal education as a privilege. Individuals in Cluster 2 reported statistically significant levels of anxiety. Implications of these results for future research and clinical practice are examined.Accepted manuscrip

Relaxation time of the topological T1 process in a two-dimensional foam

The elementary topological T1 process in a two-dimensional foam corresponds to the "flip" of one soap film with respect to the geometrical constraints. From a mechanical point of view, this T1 process is an elementary relaxation process through which the entire structure of an out-of-equilibrium foam evolves. The dynamics of this elementary relaxation process has been poorly investigated and is generally neglected during simulations of foams. We study both experimentally and theoretically the T1 dynamics in a dry two-dimensional foam. We show that the dynamics is controlled by the surface viscoelastic properties of the soap films (surface shear plus dilatational viscosity, ms+k, and Gibbs elasticity e), and is independent of the shear viscosity of the bulk liquid. Moreover, our approach illustrates that the dynamics of T1 relaxation process provides a convenient tool for measuring the surface rheological properties: we obtained e = 32+/-8 mN/m and ms+k = 1.3+/-0.7 mPa.m.s for SDS, and e = 65+/-12 mN/m and ms+k = 31+/-12 mPa.m.s for BSA, in good agreement with values reported in the literature

Electronic controller for reciprocating rotary crystallizer

An electronic controller for a reciprocating rotary crystallizer is described. The heart of this system is the electronic timer circuit. A schematic along with a detailed description of its operation is given

Preliminary design study - Oxidizer tank helium pressure regulator, Flox-Atlas, airborne Final report

Oxidizer tank helium pressure regulator compatible with fluorine-liquid oxyge

Analysis of boron carbides' electronic structure

The electronic properties of boron-rich icosahedral clusters were studied as a means of understanding the electronic structure of the icosahedral borides such as boron carbide. A lower bound was estimated on bipolaron formation energies in B12 and B11C icosahedra, and the associated distortions. While the magnitude of the distortion associated with bipolaron formation is similar in both cases, the calculated formation energies differ greatly, formation being much more favorable on B11C icosahedra. The stable positions of a divalent atom relative to an icosahedral borane was also investigated, with the result that a stable energy minimum was found when the atom is at the center of the borane, internal to the B12 cage. If incorporation of dopant atoms into B12 cages in icosahedral boride solids is feasible, novel materials might result. In addition, the normal modes of a B12H12 cluster, of the C2B10 cage in para-carborane, and of a B12 icosahedron of reduced (D sub 3d) symmetry, such as is found in the icosahedral borides, were calculated. The nature of these vibrational modes will be important in determining, for instance, the character of the electron-lattice coupling in the borides, and in analyzing the lattice contribution to the thermal conductivity