Vortices and the related principles of hydrodynamics

Here, conceptions concerning vortices are illustrated by the simplest possible examples. Mathematical formulas and similar means of presentation, which, for the most part, do not help the understanding of persons not versed therein, have been avoided as much as possible. Instead, the author has endeavored to demonstrate the phenomena by means of simple geometrical and mechanical illustrations. For the sake of clarity, the author chiefly considers currents in one plane only, a situation that can be readily represented by diagrams. Some of the peculiarities of vortices in three dimensional flow are briefly discussed

The theory of the screw propeller

Given here is a brief review of the fundamental principles of the propeller slip-stream theory and its further development through later researches, which demonstrate the connection between the propeller slip-stream theory and Frounde's so-called 'propeller blade theory.' The propeller slip-stream theory, especially in its improved form, now gives us the basis for determining the mutual influence of the parts of the blade, so that, in calculating the shape of the blade, we can get along with certain section characteristics, which have been determined once and for all. It is argued that new theories present the possibility of investigating the phenomena in the vicinity of the propeller, allowing us to calculate its action on the basis of fewer experimental values

A directed search for extraterrestrial laser signals

The focus of NASA's Search for Extraterrestrial Intelligence (SETI) Program is on microwave frequencies, where receivers have the best sensitivities for the detection of narrowband signals. Such receivers, when coupled to existing radio telescopes, form an optimal system for broad area searches over the sky. For a directed search, however, such as toward specific stars, calculations show that infrared wavelengths can be equally as effective as radio wavelengths for establishing an interstellar communication link. This is true because infrared telescopes have higher directivities (gains) that effectively compensate for the lower sensitivities of infrared receivers. The result is that, for a given level of transmitted power, the signal to noise ratio for communications is equally as good at infrared and radio wavelengths. It should also be noted that the overall sensitivities of both receiver systems are quite close to their respective fundamental limits: background thermal noise for the radio frequency system and quantum noise for the infrared receiver. Consequently, the choice of an optimum communication frequency may well be determined more by the achievable power levels of transmitters rather than the ultimate sensitivities of receivers at any specific frequency. In the infrared, CO2 laser transmitters with power levels greater than 1 MW can already be built on Earth. For a slightly more advanced civilization, a similar but enormously more powerful laser may be possible using a planetary atmosphere rich in CO2. Because of these possibilities and our own ignorance of what is really the optimum search frequency, a search for narrowband signals at infrared frequencies should be a part of a balanced SETI Program. Detection of narrowband infrared signals is best done with a heterodyne receiver functionally identical to a microwave spectral line receiver. We have built such a receiver for the detection of CO2 laser radiation at wavelengths near 10 microns. The spectrometer uses a high-speed HgCdTe diode as the photomixer and a small CO2 laser as the local oscillator. Output signals in the intermediate frequency range 0.1-2.6 GHz are processed by a 1000-channel acousto-optic signal processor. The receiver is being used on a 1.5-m telescope on Mt. Wilson to survey a selected sample of 150 nearby stars. The current status of the work is discussed along with future project plans

Polarization probes of vorticity in heavy ion collisions

We discuss the information that can be deduced from a measurement of particle (hyperon or vector meson) polarization in ultrarelativistic nuclear collisions. We describe the sensitivity of polarization to initial conditions, hydrodynamic evolution and mean free path, and find that the polarization observable is sensitive to all details and stages of the system's evolution. We suggest that an experimental investigation covering production plane and reaction plane polarizations, as well as the polarization of jet-associated particles in the plane defined by the jet and particle direction, can help in disentangling the factors contributing to this observable. Scans of polarization in energy and rapidity might also point to a change in the system's properties.Comment: In press, Phys.Rev.C. One new figure, text streamlined and edited, physics conclusions and reasoning not change

Some examples of the degradation of properties of materials in space

The space environment effects on the silver teflon covering (solar panels) of two SOLRAD SATELLITES AND NTS-Z are examined to analyze the design requirements for the Shuttle Launch Dispenser (SLD)

NH3 in IRC plus 10216

Ammonia was detected in the circumstellar envelope of IRC +10216 by means of three infrared absorption lines in the nu sup 2 band around 950/cm. The lines are fully resolved at a resolution of 0.22 km/sec and indicate that most of the circumstellar gas is accelerated to expansion velocities around 14 km/sec within a few stellar radii. The NH3 profiles indicate a rotational temperature between 400 and 700 K, and H2 density between 10 to the 8th power/cu cm and 10 to the 10th power/cu cm, and NH3 column density of 10 to the 17th power/sq cm. The H2 density indicates that the mass of the circumstellar envelope within a 1 arcsec radius is approximately 0.1 solar masses

Morphological detection of X- and Y-chromosomes in smears and paraffin-embedded tissues using a non-isotopic in situ hybridization technique (NISH)

Pharyngeal smears and paraffin-embedded tissue specimens (skeletal muscle, kidney) obtained from 10 male and 10 female individuals were evaluated using non-isotopic in situ hybridization (NISH) with commercial X- and Y-specific biotinylated probes which recognize the pericentromeric regions DXZ1 and DYZ1/DYZ3 of the X- and Y-chromosome, respectively. The results provide evidence that the morphological sex determination of a single cell can be performed by critical application of this staining method leading to one nuclear signal in ldquomalerdquo cells using the Y-specific probe whereas ldquofemalerdquo cells are negative. In situ hybridization of ldquofemalerdquo tissues with an X-specific probe results regularly in 2 signals whereas ldquomalerdquo cells show only one spot in the nucleus

Relativistic Viscous Hydrodynamics for Multi-Component Systems with Multiple Conserved Currents

We would like to formulate relativistic dissipative hydrodynamics for multi-component systems with multiple conserved currents. This is important for analyses of the hot matter created in relativistic heavy ion collisions because particle creations and annihilations of various particle species are frequently taking place there. We show that consistent formulation in such systems involves many non-trivialities, and derive constitutive equations that satisfy Onsager reciprocal relations and describe the systems without ambiguity.Comment: 4 pages, no figures - To appear in the conference proceedings for Hot Quarks 2010, June 21-26, La Londe-les-Maures, Franc