Prototype 20 watt solid-state telemetry transmitter, volume 1 Final technical report

Design and operational performance of solid state ultrahigh frequency prototype telemetry transmitte

Breaking conjugate pairing in thermostatted billiards by magnetic field

We demonstrate that in the thermostatted three-dimensional Lorentz gas the symmetry of the Lyapunov spectrum can be broken by adding to the system an external magnetic field not perpendicular to the electric field. For perpendicular field vectors, there is a Hamiltonian reformulation of the dynamics and the conjugate pairing rule still holds. This indicates that symmetric Lyapunov spectra has nothing to do with time reversal symmetry or reversibility; instead, it seems to be related to the existence of a Hamiltonian connection.Comment: 4 pages, 3 figure

Peeping at chaos: Nondestructive monitoring of chaotic systems by measuring long-time escape rates

One or more small holes provide non-destructive windows to observe corresponding closed systems, for example by measuring long time escape rates of particles as a function of hole sizes and positions. To leading order the escape rate of chaotic systems is proportional to the hole size and independent of position. Here we give exact formulas for the subsequent terms, as sums of correlation functions; these depend on hole size and position, hence yield information on the closed system dynamics. Conversely, the theory can be readily applied to experimental design, for example to control escape rates.Comment: Originally 4 pages and 2 eps figures incorporated into the text; v2 has more numerical results and discussion: now 6 pages, 4 figure

Open circular billiards and the Riemann hypothesis

A comparison of escape rates from one and from two holes in an experimental container (e.g. a laser trap) can be used to obtain information about the dynamics inside the container. If this dynamics is simple enough one can hope to obtain exact formulas. Here we obtain exact formulas for escape from a circular billiard with one and with two holes. The corresponding quantities are expressed as sums over zeroes of the Riemann zeta function. Thus we demonstrate a direct connection between recent experiments and a major unsolved problem in mathematics, the Riemann hypothesis.Comment: 5 pages, 4 embedded postscript figures; v2: more explicit on how the Reimann Hypothesis arises from a comparison of one and two hole escape rate

The Impact of HSAs on Health Care Reform: Preliminary Results after One Year

With over one year having passed since the Medicare Modernization Act ( MMA ) authorized the creation of the first individual Health Savings Accounts ( HSA ), this Article reviews the context, structure, promise, and impact of this new type of tax-advantaged account. The Article begins by briefly reviewing the context of this reform, documenting what both Presidents Clinton and Bush noted about rising costs and decreasing access. The Article then reviews the HSA legislation itself, H.R. 2596, and summarizes how HSAs operate. Part IV of this Article reviews the claims made for HSAs when H.R. 2596 passed as part of the MMA. Part V takes a preliminary look at the impact of HSAs one year after their creation. The Article concludes that HSAs represent, at most, a small piece of the overall health care reform puzzle

Transmission and Reflection in the Stadium Billiard: Time-dependent asymmetric transport

We investigate the transmission and reflection survival probabilities for the chaotic stadium billiard with two holes placed asymmetrically. Classically, these distributions are shown to have algebraic or exponential decays depending on the choice of injecting hole and exact expressions are given for the first time and confirmed numerically. As there is no reported quantum theoretical or experimental analogue we propose a model for experimental observation of the asymmetric transport using semiconductor nano-structures and comment on the relevant quantum time-scales.Comment: 4 pages, 4 figure

Survival Probability for Open Spherical Billiards

We study the survival probability for long times in an open spherical billiard, extending previous work on the circular billiard. We provide details of calculations regarding two billiard configurations, specifically a sphere with a circular hole and a sphere with a square hole. The constant terms of the long-term survival probability expansions have been derived analytically. Terms that vanish in the long time limit are investigated analytically and numerically, leading to connections with the Riemann hypothesis

A Paradox of State-Dependent Diffusion and How to Resolve It

Consider a particle diffusing in a confined volume which is divided into two equal regions. In one region the diffusion coefficient is twice the value of the diffusion coefficient in the other region. Will the particle spend equal proportions of time in the two regions in the long term? Statistical mechanics would suggest yes, since the number of accessible states in each region is presumably the same. However, another line of reasoning suggests that the particle should spend less time in the region with faster diffusion, since it will exit that region more quickly. We demonstrate with a simple microscopic model system that both predictions are consistent with the information given. Thus, specifying the diffusion rate as a function of position is not enough to characterize the behaviour of a system, even assuming the absence of external forces. We propose an alternative framework for modelling diffusive dynamics in which both the diffusion rate and equilibrium probability density for the position of the particle are specified by the modeller. We introduce a numerical method for simulating dynamics in our framework that samples from the equilibrium probability density exactly and is suitable for discontinuous diffusion coefficients.Comment: 21 pages, 6 figures. Second round of revisions. This is the version that will appear in Proc Roy So

Gravity Waves, Chaos, and Spinning Compact Binaries

Spinning compact binaries are shown to be chaotic in the Post-Newtonian expansion of the two body system. Chaos by definition is the extreme sensitivity to initial conditions and a consequent inability to predict the outcome of the evolution. As a result, the spinning pair will have unpredictable gravitational waveforms during coalescence. This poses a challenge to future gravity wave observatories which rely on a match between the data and a theoretical template.Comment: Final version published in PR

Entwicklung von Modellen zur Abschätzung der Steifigkeit und Tragfähigkeit von Holztafeln

Wohn- und Geschäftsgebäude werden überwiegend durch vertikale Einwirkungen wie Eigengewicht, Verkehrs- und Schneelast beansprucht. Horizontale Einwirkungen resultieren im Wesentlichen aus Wind, Erdbeben und Aussteifungslasten. Dach-, Decken-, und Wandbauteile müssen dabei ein räumliches Tragsystem bilden, welches die horizontalen Kräfte in die Fundamente und damit in den Baugrund ableitet. Die aussteifenden Teilsysteme können Scheiben, Rahmen oder Verbände sein, die in Material und Form variieren können. Diese Arbeit befasst sich mit Scheiben in Holzbauart und hier speziell der Holztafelbauart. Im Rahmen dieser Arbeit wurde gezeigt, welchen Einfluss die Wahl des statischen Modells und der Konstruktionsparameter, wie z.B. die Tafelform, der VM-Abstand und die Rippensteifigkeit, auf die Beanspruchungen und Verformungen eines Holztafelelements besitzen. Die Variation der Form beinhaltet den kontinuierlichen Übergang vom Rechteck über das Trapez bis hin zum Dreieck. Bei der Parameterstudie wurde ein in dieser Arbeit hergeleitetes Kopplungselement eingesetzt, welches zu einer erheblichen Reduzierung von Freiheitsgraden bei der Berechnung des FE-Modells führt. Die Untersuchungen zeigen u.a., dass schon bei Annahme steifer statt starrer Rippen alle rechteckförmigen Modelle mit und ohne direkter Rippenverbindungen annähernd das Tragverhalten entsprechend einem statisch bestimmten Schubfeldmodell aufweisen.Residential buildings and office blocks are predominantly subjected to such vertical actions as dead weight, live load and snow load. Horizontal actions are primarily those resulting from wind, earthquakes, and reinforcing loads. The roof, floor and wall members used have to form a three-dimensional structural system that transmits the horizontal forces into the foundations and thus into the subsoil. The bracing sub-systems may be diaphragms, frames or trussed frameworks, which may vary both in respect of the material used and the shape. This paper is concerned with wood panels under diaphragm actions. The paper discusses the effect the structural model used as well as the design parameters, e.g. the shape of panel, the fastener spacing, and the stiffness of the timber members, have on the effects of action and deformation of wood panels. Variations in shape imply a steady transition from the rectangle to the trapezoid and, finally, the triangle. The parameter study employed a coupling element, which was developed as part of this paper, and which allows the degrees of freedom for FE-model calculation to be reduced substantially. The investigations made show that, just by assuming stiff instead of rigid timber members, all rectangular models, with and without direct connection of these members, reveal a load-bearing behaviour which corresponds by approximation to that of a statically determinated shearwall model