Design of a nonlinear, thin-film Mach-Zehnder interferometer

A Mach-Zehnder interferometer consists of a 3 db splitter to create the two separate beams, an optical path difference to control the interference between the two beams and another 3 db coupler to reconstruct the output signal. The performance of each of its components has been investigated. Since an optical path difference is required for its function, the performance of a Mach-Zehnder interferometer is not very sensitive to construction parameters. In designing an interferometer for this work, the following considerations must be observed: the interferometer is to be made of phthalocyanine or polydiacetylene thin films; in order to avoid thermal effects which are slower, the wavelength chosen must not be absorbed in either one or two photon processes; the wavelength chosen must be easily generated (laser line); the spacing between the interferometer arms must be large enough to allow attachment of external electrodes; the vapor deposition apparatus can accept disks no larger than 0.9 inches; and the design must allow multiple layer coating in order to determine the optimum film thickness or to change to another substance

Strategic, tactical decisions and information in Rapid Manufacturing supply chain

The efficiency and agility of its supply chain is vital to the commercial success of any product. Sharing strategic and tactical information effectively within the supply chain is often a key factor in achieving this goal. This paper proposes a framework to identify strategic, tactical decisions and information. The framework is used to conduct a sector based analysis of the Rapid Manufacturing (RM) industry. The decisions and information identified include amongst others various supply chain strategies and technical information

Species Composition and Diversity of Hawk Populations in Northeastern Arkansas

Species composition and diversity of hawk populations were analyzed for northeastern Arkansas by the use of roadside censuses conducted in September through April from 1974- 1977. Data from 10 years of Jonesboro Christmas Bird Counts were also analyzed. During the roadside survey 20,174 miles were driven and 1819 raptors were counted. Ten species were observed with the Red-tailed Hawk being most abundant followed by the Marsh Hawk and the American Kestrel. Eight species were recorded from the 10 years of Christmas Bird Counts. Annual breeding bird surveys and spot records turned up three additional species making a total of 14 species in 15 years of study. Although hawk populations fluctuate from year to year, the data do not reveal any downward trend in numbers in northeastern Arkansas. Large concentrations of hawks do not appear in this region of the state until after mid-September. Populations reach a peak in December after which they decline in January. A second peak is reached in February followed by a gradual decline such that in April the American Kestrel is the only species consistently seen from the roadside. After April only a few hawks remain to nest. Both Krider\u27s and melanistic Red-tails occur here but from a total of 864 Red-tailed Hawks observed only 26 Krider\u27s and 31 melanistic or Buteo iamaicensis harlanii were recorded