Single-element coaxial injector for rocket fuel

Improved injector for oxygen difluoride and diborane has better mixing characteristics and is able to project fuel onto the wall of the combustion chamber for better cooling. It produces an essentially conical, diverging, continuous sheet of propellant mixture formed by similarly shaped and continuously impinging sheets of fuel and oxidant

Coolidge solar powered irrigation pumping project

A 150 kW solar thermal electric power plant which includes over 2100 square meters of parabolic trough type collectors and an organic Rankine cycle turbine engine was constructed on an irrigated farm. The plant is interconnected with the electrical utility grid. Operation is providing an evaluation of equipment performance and operating and maintenance requirements as well as the desirability of an on farm location

The LISA Time-Delay Interferometry Zero-Signal Solution. I: Geometrical Properties

Time-Delay Interferometry (TDI) is the data processing technique needed for generating interferometric combinations of data measured by the multiple Doppler readouts available onboard the three LISA spacecraft. Within the space of all possible interferometric combinations TDI can generate, we have derived a specific combination that has zero-response to the gravitational wave signal, and called it the {\it Zero-Signal Solution} (ZSS). This is a two-parameter family of linear combinations of the generators of the TDI space, and its response to a gravitational wave becomes null when these two parameters coincide with the values of the angles of the source location in the sky. Remarkably, the ZSS does not rely on any assumptions about the gravitational waveform, and in fact it works for waveforms of any kind. Our approach is analogous to the data analysis method introduced by G\"ursel & Tinto in the context of networks of Earth-based, wide-band, interferometric gravitational wave detectors observing in coincidence a gravitational wave burst. The ZSS should be regarded as an application of the G\"ursel & Tinto method to the LISA data.Comment: 29 pages, 17 Figure

Can gravitational waves be detected in quasar microlensing?

Studies of the lensed quasar ${\rm Q}0957+561 {\rm A,B}$ have shown evidence for microlensing in the brightness history of the quasar images. It had been suggested that a frequency offset between the brightness fluctuations in each of the two images might possibly be caused by gravitational radiation generated by a massive black hole binary at the center of the lensing galaxy. This paper demonstrates that the fluctuations produced by such a source of gravitational waves will be too small to account for the observed frequency offsets.Comment: 10 pages, 1 fig; submitted to Ap

Science Icebreaker Activities: An Example from Gravitational Wave Astronomy

At the beginning of a class or meeting an icebreaker activity is often used to help loosen the group and get everyone talking. Our motivation is to develop activities that serve the purpose of an icebreaker, but are designed to enhance and supplement a science-oriented agenda. The subject of this article is an icebreaker activity related to gravitational wave astronomy. We first describe the unique gravitational wave signals from three distinct sources: monochromatic binaries, merging compact objects, and extreme mass ratio encounters. These signals form the basis of the activity where participants work to match an ideal gravitational wave signal with noisy detector output for each type of source.Comment: Accepted to The Physics Teacher. Original manuscript divided into two papers at the request of the referee. For a related paper on gravitational wave observatories see physics/050920

Cast Fe-base cylinder/regenerator housing alloy

The development of an iron-base alloy that can meet the requirements of automotive Stirling engine cylinders and regenerator housings is described. Alloy requirements are as follows: a cast alloy, stress for 5000-hr rupture life of 200 MPa (29 ksi) at 775 C (1427 F), oxidation/corrosion resistance comparable to that of N-155, compatibility with hydrogen, and an alloy cost less than or equal to that of 19-9DL. The preliminary screening and evaluation of ten alloys are described