Worldwide flight and ground-based exposure of composite materials

The long-term durability of those advanced composite materials which are applicable to aircraft structures was discussed. The composite components of various military and commercial aircraft and helicopters were reviewed. Both ground exposure and flight service were assessed in terms of their impact upon composite structure durability. The ACEE Program is mentioned briefly

Attribution of a Multinational Corporation\u27s Net Income: The Position of Unitary States Regarding Combined Reporting

A complex and controversial aspect of state taxation of business income involves the attribution of a multinational corporation\u27s (MNC\u27s) net income. This Article examines the nature and scope of the controversy that stems from the conflicting views of states that promote a unitary taxation system, and MNCs as well as the Department of Treasury (Treasury) that oppose this position. Section IV illustrates why the unitary business principle is currently the only viable, fair, and feasible method available to the states for the geographical assignment of an MNC\u27s net income. Section V analyzes the MNCs\u27 arguments both against worldwide combined reporting and in favor of alternative accounting methods. In addition, this Article also considers the different positions of foreign and domestic MNCs in regard to worldwide combined income reporting. Section II explores the basic assumptions upon which various attribution rules are based and sets forth the consequences of competing alternative rules. This section also examines the underlying conflict between: (1) the sourcing of net income and separate accounting, subject to Internal Revenue Code (IRC) § 482 adjustments (as administered by the Internal Revenue Service (IRS)); and (2) the unitary business principle. Substantial differences between the theory and application of these various rules have surfaced as states exert their individual powers of taxation within the limits of constitutional and practical restraints. As applied to MNCs, the appropriateness and reasonableness of any of these rules depend on one\u27s view of what constitutes an MNC and a reasonable exercise of state taxing power. If an MNC is viewed as a single economic unit rather than as a group of independent businesses, then combined tax reporting is appropriate. When an MNC is viewed as a unitary economic entity, though, nationality becomes a consideration. An attribution rule that is reasonable when used to determine the domestic income of a foreign MNC is not necessarily appropriate as applied to a domestic MNC. Different attribution rules may be necessary for domestic MNCs with world operations head quartered in the United States, as compared with foreign MNCs headquartered in other nations. A discussion of concepts basic to these methods follows

Lifetime and polarization of the radiative decay of excitons, biexcitons and trions in CdSe nanocrystal quantum dots

Using the pseudopotential configuration-interaction method, we calculate the intrinsic lifetime and polarization of the radiative decay of single excitons (X), positive and negative trions (X+ and X−), and biexcitons (XX) in CdSe nanocrystal quantum dots. We investigate the effects of the inclusion of increasingly more complex many-body treatments, starting from the single-particle approach and culminating with the configuration-interaction scheme. Our configuration-interaction results for the size dependence of the single-exciton radiative lifetime at room temperature are in excellent agreement with recent experimental data. We also find the following. (i) Whereas the polarization of the bright exciton emission is always perpendicular to the hexagonal c axis, the polarization of the dark exciton switches from perpendicular to parallel to the hexagonal c axis in large dots, in agreement with experiment. (ii) The ratio of the radiative lifetimes of mono- and biexcitons (X):(XX) is ~1:1 in large dots (R=19.2 Å). This ratio increases with decreasing nanocrystal size, approaching 2 in small dots (R=10.3 Å). (iii) The calculated ratio (X+):(X−) between positive and negative trion lifetimes is close to 2 for all dot sizes considered

Measurement and analysis of critical crack tip processes during fatigue crack growth

The mechanics of fatigue crack growth under constant-amplitudes and variable-amplitude loading were examined. Critical loading histories involving relatively simple overload and overload/underload cycles were studied to provide a basic understanding of the underlying physical processes controlling crack growth. The material used for this study was 7091-T7E69, a powder metallurgy aluminum alloy. Local crack-tip parameters were measured at various times before, during, and after the overloads, these include crack-tip opening loads and displacements, and crack-tip strain fields. The latter were useed, in combination with the materials cyclic and monotonic stress-strain properties, to compute crack-tip residual stresses. The experimental results are also compared with analytical predictions obtained using the FAST-2 computer code. The sensitivity of the analytical model to constant-amplitude fatigue crack growth rate properties and to through-thickness constrain are studied

The Influence of Engagement Upon Success and Persistence of Online Undergraduates

Institutions of higher education, states, and government agencies are seeking avenues for increasing access, improving learning outcomes, and increasing student retention. The majority of chief academic officers polled indicate that online learning is key to the growth of their institutions, while simultaneously indicating concern that online learners are less likely to succeed and persist. A common construct for how institutions can facilitate student success and persistence is the notion of engagement . Since 2000, campuses have relied upon the National Survey of Student Engagement (NSSE) to guide institutional policies and practices supporting student success

Newspapers and their Relationship to the Black Agenda

The news media, by print or electronics, influences and shapes society\u27s attitudes; it is essential then, if not vital, that the media accurately reflect every aspect of our society - including the good, the bad, and the ugly. By keeping this nation - as well as the world - in its proper context, we can better understand - and thus better solve - the problems that envelop us, such as racism, sexism, unemployment, hazardous waste, and the consequences of a nuclear meltdown. To help present an accurate picture of who we are and what\u27s happening around us, the news media need input from every diverse segment of society - and not merely from that limited view of society held by many of our unenlightened publishers, editors, news supervisors, and reporters