NNEP: The Navy NASA Engine Program

A computer code capable of simulating almost any conceivable turbine engine is described. This code uses stacked component maps and multiple flowpaths to simulate variable cycle engines with variable component geometry. It is capable of design and off-design (matching) calculations and can optimize free variables such as nozzle areas to minimize specific fuel consumption

Not All Bad Apples Spoil the Bunch: Order Effects on the Evaluation of Groups

When group members are encountered in a random sequential order, people expect the first (vs. middle or last) member to be more diagnostic of the group. Therefore, they weigh the performance of the first (vs. middle or last) more heavily in their predictions and decisions about the whole group

The First-Member Heuristic: Group Members Labeled “First” Influence Judgment and Treatment of Groups

People often make judgments about a group (e.g., immigrants from a specific country) based on information about a single group member. Seven studies (N = 1,929) tested the hypothesis that people will expect the performance of an arbitrarily ordered group to match that of the group member in the first position of a sequence more closely than that of group members in other positions. This greater perceived diagnosticity of the first member will in turn affect how people treat the group. This pattern of judgment and treatment of groups, labeled the “firstmember heuristic,” generalized across various performance contexts (e.g., gymnastic outine, relay race, job performance), and regardless of whether the focal member performed poorly or well (Studies 1-3). Consistent with the notion that first members are deemed most informative, participants were most likely to turn to the member in the first (vs. other) position to learn about the group (Study 4). Further, through their disproportionate influence on the expected performance of other group members, first members’ performances also influenced participants’ support of policies that would benefit or hurt a group (Study 5) and their likelihood to join a group (Study 6). Finally, perceived group homogeneity moderated the first-member heuristic, such that it attenuated for nonhomogeneous groups (Study 7)

Computer optimization of reactor-thermoelectric space power systems

A computer simulation and optimization code that has been developed for nuclear space power systems is described. The results of using this code to analyze two reactor-thermoelectric systems are presented

Integrating theories of self-control and motivation to advance endurance performance

Self-control is a burgeoning research topic within sport and motivational psychology. Following efforts to define and contextualize self-control, characteristics of self-control are considered that have important implications for sport performance. We describe and evaluate various theoretical perspectives on self-control, including limited resources, shifting priorities, and opportunity-costs. The research described includes sport-specific research but also studies that focus on general motivational principles that look beyond sport-specific phenomena. We propose that attentional, rather than limited resource, explanations of self-control have more value for athletic performance. Moreover, we integrate self-control ideas with descriptions of motivational phenomena to derive novel hypotheses concerning how self-control can be optimized during sport performance. We explain how minimizing desire-goal conflicts by fusing self-control processes and performance goals can delay aversive consequences of self-control that may impede performance. We also suggest that autonomous performance goals are an important motivational input that enhances the effectiveness of self-control processes by a) reducing the salience of the desire to reduce performance-related discomfort, b) increasing attentional resources towards optimal performance, and c) optimizing monitoring and modification of self-control processes. These extensions to knowledge help map out empirical agenda which may drive theoretical advances and deepen understanding of how to improve self-control during performance

Ultracold neutrons, quantum effects of gravity and the Weak Equivalence Principle

We consider an extension of the recent experiment with ultracold neutrons and the quantization of its vertical motion in order to test the Weak Equivalence Principle. We show that an improvement on the energy resolution of the experiment may allow to establish a modest limit to the Weak Equivalence Principle and on the gravitational screening constant. We also discuss the influence of a possible new interaction of Nature.Comment: Revtex4, 4 pages. Discussion on the equivalence principle altered. Bound is improve

The Laser Astrometric Test of Relativity Mission

This paper discusses new fundamental physics experiment to test relativistic gravity at the accuracy better than the effects of the 2nd order in the gravitational field strength. The Laser Astrometric Test Of Relativity (LATOR) mission uses laser interferometry between two micro-spacecraft whose lines of sight pass close by the Sun to accurately measure deflection of light in the solar gravity. The key element of the experimental design is a redundant geometry optical truss provided by a long-baseline (100 m) multi-channel stellar optical interferometer placed on the International Space Station. The geometric redundancy enables LATOR to measure the departure from Euclidean geometry caused by the solar gravity field to a very high accuracy. LATOR will not only improve the value of the parameterized post-Newtonian (PPN) parameter gamma to unprecedented levels of accuracy of 1 part in 1e8, it will also reach ability to measure effects of the next post-Newtonian order (1/c^4) of light deflection resulting from gravity's intrinsic non-linearity. The solar quadrupole moment parameter, J2, will be measured with high precision, as well as a variety of other relativistic. LATOR will lead to very robust advances in the tests of fundamental physics: this mission could discover a violation or extension of general relativity, or reveal the presence of an additional long range interaction in the physical law. There are no analogs to the LATOR experiment; it is unique and is a natural culmination of solar system gravity experiments.Comment: 8 pages, 2 figures, invited talk given at the Second International Conference on Particle and Fundamental Physics in Space (SpacePart'03), 10-12 December 2003, Washington, D

Lorentz Invariance and the Cosmological Constant

Non-trivial solutions in string field theory may lead to the spontaneous breaking of Lorentz invariance and to new tensor-matter interactions. It is argued that requiring the contribution of the vacuum expectation values of Lorentz tensors to account for the vacuum energy up to the level that $\Omega_{0}^{\Lambda} = 0.5$ implies the new interactions range is $\lambda \sim 10^{-4} m$. These conjectured violations of the Lorentz symmetry are consistent with the most stringent experimental limits.Comment: 13 pages, plain Latex. This essay was selected for an honorable mention in the 1997 Gravity Research Foundation essay competio