Mechanics of Fracture in Adhesive Joints

Interdependence of continuum mechanics and physical chemistry in failure analysis of adhesive

Paramagnetic resonance effect in viscoelastic materials Annual progress report, 1 Jan. - 31 Dec. 1968

Electron paramagnetic resonance investigation of fracture in viscoelastic material

The SEC's "Fair Value" Standard for Mutual Fund Investment in Restricted Shares and Other Illiquid Securities

Mutual funds generally do not invest in venture capital, private equity, or restricted shares of public companies. Consequently, individuals who desire to invest in such securities are unable to do so through diversified mutual funds. In this paper, we identify public policies and regulations that discourage mutual fund involvement in the markets for illiquid equity. We also present evidence that changes in SEC policy caused mutual funds to retreat from investing in illiquid equity. Under the Investment Company Act of l940, the SEC requires mutual fund boards to determine and report the “fair value” of their investments in restricted shares and other illiquid equity claims. The SEC interprets fair value to mean value in current sale. Under the Investment Company Act, fair value reporting is a “certification” standard that presumes investors rely on the value representations of the fund board and its auditors. We consider whether alternatives to certification and current sale valuation could reduce barriers to mutual fund investment, without exposing individuals who invest in mutual funds to excessive risk or potential manipulation. To assess the effects of public policies, we analyze recent efforts of the SEC to apply the fair-value standard and examine court decisions arising from subsequent litigation. We also analyze the financial economics literature concerning discounts for illiquidity and the implications for valuing restricted shares. The paper concludes with a discussion of policy alternatives, including allowing funds to rely more on “transparency” in lieu of certification and allowing funds more latitude in determining and reporting the values of their illiquid securities.

The open cluster initial-final mass relationship and the high-mass tail of the white dwarf distribution

Recent studies of white dwarfs in open clusters have provided new constraints on the initial - final mass relationship (IFMR) for main sequence stars with masses in the range 2.5 - 6.5 Mo. We re-evaluate the ensemble of data that determines the IFMR and argue that the IFMR can be characterised by a mean initial-final mass relationship about which there is an intrinsic scatter. We investigate the consequences of the IFMR for the observed mass distribution of field white dwarfs using population synthesis calculations. We show that while a linear IFMR predicts a mass distribution that is in reasonable agreement with the recent results from the PG survey, the data are better fitted by an IFMR with some curvature. Our calculations indicate that a significant (~28%) percentage of white dwarfs originating from single star evolution have masses in excess of ~0.8 Mo, obviating the necessity for postulating the existence of a dominant population of high-mass white dwarfs that arise from binary star mergers.Comment: 5 pages, 2 color Postscript figures. Accepted for publication in MNRA

Space-based tests of gravity with laser ranging

Existing capabilities in laser ranging, optical interferometry and metrology, in combination with precision frequency standards, atom-based quantum sensors, and drag-free technologies, are critical for the space-based tests of fundamental physics; as a result, of the recent progress in these disciplines, the entire area is poised for major advances. Thus, accurate ranging to the Moon and Mars will provide significant improvements in several gravity tests, namely the equivalence principle, geodetic precession, PPN parameters $\beta$ and $\gamma$, and possible variation of the gravitational constant $G$. Other tests will become possible with development of an optical architecture that would allow proceeding from meter to centimeter to millimeter range accuracies on interplanetary distances. Motivated by anticipated accuracy gains, we discuss the recent renaissance in lunar laser ranging and consider future relativistic gravity experiments with precision laser ranging over interplanetary distances.Comment: 14 pages, 2 figures, 1 table. To appear in the proceedings of the International Workshop "From Quantum to Cosmos: Fundamental Physics Research in Space", 21-24 May 2006, Warrenton, Virginia, USA http://physics.jpl.nasa.gov/quantum-to-cosmos

Numerical solutions of several reflected shock-wave flow fields with nonequilibrium chemical reactions

The method of characteristics for a chemically reacting gas is used in the construction of the time-dependent, one-dimensional flow field resulting from the normal reflection of an incident shock wave at the end wall of a shock tube. Nonequilibrium chemical reactions are allowed behind both the incident and reflected shock waves. All the solutions are evaluated for oxygen, but the results are generally representative of any inviscid, nonconducting, and nonradiating diatomic gas. The solutions clearly show that: (1) both the incident- and reflected-shock chemical relaxation times are important in governing the time to attain steady state thermodynamic properties; and (2) adjacent to the end wall, an excess-entropy layer develops wherein the steady state values of all the thermodynamic variables except pressure differ significantly from their corresponding Rankine-Hugoniot equilibrium values

Distributed-Pair Programming can work well and is not just Distributed Pair-Programming

Background: Distributed Pair Programming can be performed via screensharing or via a distributed IDE. The latter offers the freedom of concurrent editing (which may be helpful or damaging) and has even more awareness deficits than screen sharing. Objective: Characterize how competent distributed pair programmers may handle this additional freedom and these additional awareness deficits and characterize the impacts on the pair programming process. Method: A revelatory case study, based on direct observation of a single, highly competent distributed pair of industrial software developers during a 3-day collaboration. We use recordings of these sessions and conceptualize the phenomena seen. Results: 1. Skilled pairs may bridge the awareness deficits without visible obstruction of the overall process. 2. Skilled pairs may use the additional editing freedom in a useful limited fashion, resulting in potentially better fluency of the process than local pair programming. Conclusion: When applied skillfully in an appropriate context, distributed-pair programming can (not will!) work at least as well as local pair programming

Carrion Beetles (Coleoptera: Silphidae) of Wisconsin

The first comprehensive faunal survey of the carrion beetles (Coleoptera: Silphidae) of Wisconsin is presented. Six genera and 14 species are recorded from the state, including a new state record, Heterosilpha ramosa (Say). Nicrophorus americanus Olivier was not recovered during this study. An annotated checklist includes species-specific geographical and temporal distributions, remarks on foods and habitat, and counties of specimen collections for each species

ECONOMIC THRESHOLDS: AN APPLICATION TO FLORICULTURE

This paper introduces conjunctive optimal pest management and production decision rules applied to the floriculture industry. A grower is faced with optimally controlling multiple pests and applying cultural controls to maximize the expected net present value of benefits within a discrete time framework, subject to biological and marketing constraints.Crop Production/Industries,