Literature review and experimental investigation of heat pipes

Tests on heat pipes determine operational limits, external boundary conditions, noncondensable gas effects, startup behavior, and geometric configurations. Experiment consists of design, construction, and testing of an apparatus for measuring wick properties, conventional heat pipes and coplanar heat pipes

Dichte- und Viskositätsmessungen an Quecksilber und hochverdünnten Kalium- und Cäsiumamalgamen vom Erstarrungspunkt bis + 30°C

Die Temperaturabhängigkeit der Dichte und der Viskosität des Quecksilbers sowie hochverdünnter Kalium- und Cäsiumamalgame wird von 30° C bis zum Erstarrungspunkt gemessen. Der Volumen-Ausdehnungskoeffizient α ist bei Cs-Amalgamen größer als bei K-Amalgamen und nimmt von αHg beginnend proportional der Alkalimetall-Konzentration zu. Auch die spez. Volumina der Amalgame nehmen von dem des reinen Quecksilbers an proportional der Konzentration zu. Die hieraus berechneten Atomvolumen (VK) und (VCs) der beiden Alkalimetalle im Amalgam sind nur um etwa 10% verschieden und von der Konzentration unabhängig. Sie nehmen linear mit der Temperatur zu; die Volumenkontraktion δ hingegen verringert sich mit zunehmender Temperatur. — Die Temperaturabhängigkeit der Viskosität η läßt sich mit einer Genauigkeit bis zu einigen Zehntel Promille durch η = η0·eq/RT wiedergeben mit η0η0 = const; die Ansätze η0 ∾ T-1/2,η0 ∾ T1/2, η0 ∾ T ergeben größere Abweichungen. Für reines Quecksilber ist die Platzwechselenergie q = 657,9 cal, für K-Amalgam von c′ = 1,91 Atomen K in 1000 Atomen Amalgam ist qK = 714,6 cal und für gleichverdünntes Cs-Amalgam qCS = 690,4. Hieraus und aus dem Dichteverhalten wird gefolgert, daß die K-Atome eine (weniger dicht gepackte) Hg-Hülle von größerem Volumen mit sich führen als die Cs-Atome. Das Volumen φ dieser Hülle läßt sich berechnen unter Verwendung eines Ansatzes von Einstein für die Viskosität einer Lösung von größeren Kugeln in einem Medium kleinerer Kugeln. Aus der Temperaturabhängigkeit von φ erhält man die zur Abtrennung von 1 g-Atom Quecksilber erforderliche Energie ε; εκ = 278,9 cal, εCs= 359,3 cal. εκ ist kleiner als εCs, weil die Hg-Atome um die K-Atome weniger dicht gepackt sind. — Zwischen der Volumenkontraktion δ der Alkaliatome im Amalgam und φ besteht eine lineare Beziehung; δ setzt sich additiv aus einem temperaturunabhängigen und einem temperaturabhängigen Anteil zusammen. Beide Anteile kommen beim Cs-Amalgam stärker zur Geltung als beim K-Amalgam

Alternating bid bargaining with a smallest money unit

Bargaining

Measuring Polynomial Invariants of Multi-Party Quantum States

We present networks for directly estimating the polynomial invariants of multi-party quantum states under local transformations. The structure of these networks is closely related to the structure of the invariants themselves and this lends a physical interpretation to these otherwise abstract mathematical quantities. Specifically, our networks estimate the invariants under local unitary (LU) transformations and under stochastic local operations and classical communication (SLOCC). Our networks can estimate the LU invariants for multi-party states, where each party can have a Hilbert space of arbitrary dimension and the SLOCC invariants for multi-qubit states. We analyze the statistical efficiency of our networks compared to methods based on estimating the state coefficients and calculating the invariants.Comment: 8 pages, 4 figures, RevTex4, v2 references update

An analytical and experimental study of heat transfer in a simulated Martian atmosphere Final report, 1 Nov. 1968 - 15 Oct. 1969

Convective heat transfer in simulated Martian atmospher

The StarScan plate measuring machine: overview and calibrations

The StarScan machine at the U.S. Naval Observatory (USNO) completed measuring photographic astrograph plates to allow determination of proper motions for the USNO CCD Astrograph Catalog (UCAC) program. All applicable 1940 AGK2 plates, about 2200 Hamburg Zone Astrograph plates, 900 Black Birch (USNO Twin Astrograph) plates, and 300 Lick Astrograph plates have been measured. StarScan comprises of a CCD camera, telecentric lens, air-bearing granite table, stepper motor screws, and Heidenhain scales to operate in a step-stare mode. The repeatability of StarScan measures is about 0.2 micrometer. The CCD mapping as well as the global table coordinate system has been calibrated using a special dot calibration plate and the overall accuracy of StarScan x,y data is derived to be 0.5 micrometer. Application to real photographic plate data shows that position information of at least 0.65 micrometer accuracy can be extracted from course grain 103a-type emulsion astrometric plates. Transformations between "direct" and "reverse" measures of fine grain emulsion plate measures are obtained on the 0.3 micrometer level per well exposed stellar image and coordinate, which is at the limit of the StarScan machine.Comment: 24 pages, 8 figures, accepted for PAS

A methodology for the decomposition of discrete event models for parallel simulation

Parallel simulation has presented the possibility of performing high-speed simulation. However, when attempting to make a link between the requirements of parallel simulation and discrete event simulation used in commercial areas such as manufacturing, a major problem arises. This lies in the decomposition of the simulation into a series of concurrently executing objects. Using the activity cycle diagram simulation technique as an illustrative example, this paper suggests a solution to this decomposition problem. This is discussed within the context of providing a conceptually seamless methodology for translating simulation models into a form which can exploit the benefits of parallel computing

Technology requirements for advanced earth-orbital transportation systems, dual-mode propulsion

The application of dual-mode propulsion concepts to fully reusable single-stage-to-orbit (SSTO) vehicles is discussed. Dual-mode propulsion uses main rocket engines that consume hydrocarbon fuels as well as liquid hydrogen fuel. Liquid oxygen is used as the oxidizer. These engine concepts were integrated into transportation vehicle designs capable of vertical takeoff, delivering a payload to earth orbit, and return to earth with a horizontal landing. Benefits of these vehicles were assessed and compared with vehicles using single-mode propulsion (liquid hydrogen and oxygen engines). Technology requirements for such advanced transportation systems were identified. Figures of merit, including life-cycle cost savings and research costs, were derived for dual-mode technology programs, and were used for assessments of potential benefits of proposed technology activities. Dual-mode propulsion concepts display potential for significant cost and performance benefits when applied to SSTO vehicles