Nonlinear Equations of Equilibrium for Elastic Helicopter or Wind Turbine Blades Undergoing Moderate Deformation

A set of nonlinear equations of equilibrium for an elastic wind turbine or helicopter blades are presented. These equations are derived for the case of small strains and moderate rotations (slopes). The derivation includes several assumptions which are carefully stated. For the convenience of potential users the equations are developed with respect to two different systems of coordinates, the undeformed and the deformed coordinates of the blade. Furthermore, the loads acting on the blade are given in a general form so as to make them suitable for a variety of applications. The equations obtained in the study are compared with those obtained in previous studies

Molecular characterization of an anion pump. The ArsB protein is the membrane anchor for the ArsA protein

R-factor mediated bacterial resistance to arsenical salts occurs by active extrusion of the toxic oxyanions from cells of gram negative bacteria. The ars operon of the conjugative plasmid R773 encodes an anion pump. The pump has two polypeptide components. The catalytic subunit, the ArsA protein, is an oxyanion-stimulated ATPase. The membrane component, the ArsB protein, has been localized in the inner membrane of Escherichia coli. The ArsA and ArsB proteins have been postulated to form a membrane complex which functions as an anion-translocating ATPase. In this study evidence is presented showing that expression of the arsB gene is required to anchor the ArsA protein to the inner membrane. Binding studies with purified ArsA to membranes with and without the arsB gene product confirm this requirement. Membranes of uncA mutants containing both the ArsA and ArsB proteins exhibit arsenite(antimonite)-stimulated ATPase activity. These results support the model in which the ArsA protein is the catalytic energy transducing component of the anion pump, whereas the integral membrane ArsB protein serves as both the anion channel and membrane binding site for the ArsA protein

Pension Inequality

Pensions may contribute to male/female or black/white inequality to the extent that white males are more likely to receive pensions than are other groups. Conditional on receiving pensions, the value of pension benefits varies because white males have the highest level of expected tenure atretirement. By using a combination of the Current Population Survey and the 1980 Banker's Trust Corpprate Pension Plan Study, we find that the existence of pension plans contributes to black/white inequality but leaves male/female inequality unchanged among whites. Even though females are less likely tor eceive pensions than males, those females who do receive pensions enjoy generous ones. Among blacks, pensions exacerbate sex differences because black women are only about 75% as likely to receive pensions as black males.

Rank-Order Tournaments as Optimum Labor Contracts

This paper analyzes compensation schemes which pay according to an individual's ordinal rank in an organization rather than his output level. When workers are risk neutral, it is shown that wages based upon rank induce the same efficient allocation of resources as an incentive reward scheme based on individual output levels. Under some circumstances, risk-averse workers actually prefer to be paid on the basis of rank. In addition, if workers are heterogeneous inability, low-quality workers attempt to contaminate high-quality firms, resulting in adverse selection. However, if ability is known in advance, a competitive handicapping structure exists which allows all workers to compete efficiently in the same organization.