Stratification calculations in a heated cryogenic oxygen storage tank at zero gravity

A cylindrical one-dimensional model of the Apollo cyrogenic oxygen storage tank has been developed to study the effect of stratification in the tank. Zero gravity was assumed, and only the thermally induced motions were considered. The governing equations were derived from conservation laws and solved on a digital computer. Realistic thermodynamic and transport properties were used. Calculations were made for a wide range of conditions. The results show the fluid behavior to be dependent on the quantity in the tank or equivalently the bulk fluid temperature. For high quantities (low temperatures) the tank pressure rose rapidly with heat addition, the heater temperature remained low, and significant pressure drop potentials accrued. For low quantities the tank pressure rose more slowly with heat addition and the heater temperature became high. A high degree of stratification resulted for all conditions; however, the stratified region extended appreciably into the tank only for the lowest tank quantity

Space shuttle propulsion systems on-board checkout and monitoring system development study. Volume 1 - Summary Final report

Development of onboard checkout equipment and performance monitoring capability for space shuttles - Vol.

Macroscopic transport by synthetic molecular machines

Nature uses molecular motors and machines in virtually every significant biological process, but demonstrating that simpler artificial structures operating through the same gross mechanisms can be interfaced with—and perform physical tasks in—the macroscopic world represents a significant hurdle for molecular nanotechnology. Here we describe a wholly synthetic molecular system that converts an external energy source (light) into biased brownian motion to transport a macroscopic cargo and do measurable work. The millimetre-scale directional transport of a liquid on a surface is achieved by using the biased brownian motion of stimuli-responsive rotaxanes (‘molecular shuttles’) to expose or conceal fluoroalkane residues and thereby modify surface tension. The collective operation of a monolayer of the molecular shuttles is sufficient to power the movement of a microlitre droplet of diiodomethane up a twelve-degree incline.

What impressions do users have after a ride in an automated shuttle? An interview study

In the future, automated shuttles may provide on-demand transport and serve as feeders to public transport systems. However, automated shuttles will only become widely used if they are accepted by the public. This paper presents results of an interview study with 30 users of an automated shuttle on the EUREF (Europäisches Energieforum) campus in Berlin-Schöneberg to obtain in-depth understanding of the acceptance of automated shuttles as feeders to public transport systems. From the interviews, we identified 340 quotes, which were classified into six categories: (1) expectations about the capabilities of the automated shuttle (10% of quotes), (2) evaluation of the shuttle performance (10%), (3) service quality (34%), (4) risk and benefit perception (15%), (5) travel purpose (25%), and (6) trust (6%). The quotes indicated that respondents had idealized expectations about the technological capabilities of the automated shuttle, which may have been fostered by the media. Respondents were positive about the idea of using automated shuttles as feeders to public transport systems but did not believe that the shuttle will allow them to engage in cognitively demanding activities such as working. Furthermore, 20% of respondents indicated to prefer supervision of shuttles via an external control room or steward on board over unsupervised automation. In conclusion, even though the current automated shuttle did not live up to the respondents’ expectations, respondents still perceived automated shuttles as a viable option for feeders to public transport systems.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Transport and PlanningHuman-Robot InteractionIntelligent VehiclesTransport and Plannin

Noise and Bistabilities in Quantum Shuttles

We present a study of current fluctuations in two models proposed as quantum shuttles. Based on a numerical evaluation of the first three cumulants of the full counting statistics we have recently shown that a giant enhancement of the zero-frequency current noise in a single-dot quantum shuttle can be explained in terms of a bistable switching between two current channels. By applying the same method to a quantum shuttle consisting of a vibrating quantum dot array, we show that the same mechanism is responsible for a giant enhancement of the noise in this model, although arising from very different physics. The interpretation is further supported by a numerical evaluation of the finite-frequency noise. For both models we give numerical results for the effective switching rates.Comment: 4 pages, 4 figures, Contribution to ICNF 2005, Salamanca, Spain, September, 200

A re-appraisal of the reliability of the 20 m multi-stage shuttle run test

This is the author's PDF version of an article published in European journal of applied physiology in 2007. The original publication is available at www.springerlink.co

Coulomb Blockade in a Coupled Nanomechanical Electron Shuttle

We demonstrate single electron shuttling through two coupled nanomechanical pendula. The pendula are realized as nanopillars etched out of the semiconductor substrate. Coulomb blockade is found at room temperature, allowing metrological applications. By controlling the mechanical shuttling frequency we are able to validate the different regimes of electron shuttling