Objective transmission gratings for large Schmidt telescopes

Several lamellar gratings of 18-in. aperture, with 300 diffraction elements per inch, have been made for determining stellar spectra with wide angle telescopes. Central orders are missing at λ4800, and weak at adjacent wavelengths. The two, equal first orders are about 1^m weaker than spectra by a prism or echelette grating. Dispersion is linear. The procedure of manufacture is adaptable to larger size. The wavelength at which the central order is missing can be controlled by varying the lamellae thickness. The lamellae are evaporated strips of quartz of 0.5-µ thickness, covering half the face of the support a spectacle crown, plane parallel plate of ¾-in. thickness. The lamellae were deposited by thermal evaporation

The rise, the fall, and ... : the emerging recovery of project finance transport

Recent developments in emerging financial markets have dramatically changed the appetite for (and terms of) transport infrastructure projects. As a result of defaults in Asia and Russia and devaluations in Asia, Brazil, and Russia, political and currency and exchange risk premia have increased dramatically. Given large needs for sovereign debt financing, infrastructure project finance will be seeking guarantees at the same time as governments are issuing primary securities. Large portfolio outflows in emerging market funds mean that the sources of both equity and debt capital that became available in the mid-1990s are drying up for all but the most creditworthy projects. Moreover, real economic effects from financial events have consequences in the transport sector, since transport is a derived demand. Any decline in real economic activity is felt quickly in traffic levels and revenues. Currency devaluations that help spur exports may generate higher volumes for seaports and air cargo activity. These effects vary by sector, especially over the medium to longer term. Declines in real economic activity make matters especially difficult for toll roads, as drivers shift to free alternatives and reduce the number of trips taken. What does all this mean for project finance in transport? Risks have increased. Debt finance costs more. The available tenor of debt instruments has shortened and more equity is required for projects. The sources and availability of equity finance have changed. Project finance efforts have shifted from new projects to the privatization, rehabilitation, and expansion of existing facilities. And a"superclass"of sponsors, bankers, and investors has emerged. Failures and mistakes in project finance deals in the 1990s were sharp and persistent. But much has been learned about sound project economics, conservative financial structures, comprehensive sensitivity analysis, the effects of macroeconomic factors, and the need for proper incentives and sound institutional and regulatory arrangements.Banks&Banking Reform,Payment Systems&Infrastructure,Financial Intermediation,Labor Policies,Public Sector Economics&Finance,Housing Finance,Public Sector Economics&Finance,Banks&Banking Reform,Financial Intermediation,Municipal Financial Management

Coupled Riccati equations for complex plane constraint

A new Linear Quadratic Gaussian design method is presented which provides prescribed imaginary axis pole placement for optimal control and estimation systems. This procedure contributes another degree of design freedom to flexible spacecraft control. Current design methods which interject modal damping into the system tend to have little affect on modal frequencies, i.e., they predictably shift open plant poles horizontally in the complex plane to form the closed loop controller or estimator pole constellation, but make little provision for vertical (imaginary axis) pole shifts. Imaginary axis shifts which reduce the closed loop model frequencies (the bandwidths) are desirable since they reduce the sensitivity of the system to noise disturbances. The new method drives the closed loop modal frequencies to predictable (specified) levels, frequencies as low as zero rad/sec (real axis pole placement) can be achieved. The design procedure works through rotational and translational destabilizations of the plant, and a coupling of two independently solved algebraic Riccati equations through a structured state weighting matrix. Two new concepts, gain transference and Q equivalency, are introduced and their use shown

The long and winding path to private financing and regulation of toll roads

Road transport has long been the dominant form of transport for freight and passenger movement throughout the world. Because most road projects require investments with long amortization periods and because many projects do not generate enough demand to become self-financing through some type of user fee or toll, the road sector remains in the hands of the public sector to a much greater extent than other transport activities. But governments throughout the world, including those of many poor African and South Asian countries, are commercializing their operations to cut costs, improve user orientation, and increase sector-specific revenue. There seems to be demand for toll roads in specific settings, but the problems met by many of this"first generation"of road concessions-from Mexico to Thailand-have given toll projects a bad reputation. Many mistakes were made, and tolling is obviously not the best solution for every road. Most of the alternatives aim at improving efficiency (lowering costs). But there are many ways of getting the private sector involved in toll roads, thus reducing public sector financing requirements for the sector. Understanding the context in which toll roads are viable is essential both for their initial success and for effective long-run regulation. The authors provide a broad overview of issues at stake from the viewpoint of both privatization teams and regulators responsible for supervising contractual commitments of private operators and the government, to each other and to users.Urban Services to the Poor,Roads&Highways,Public Sector Economics&Finance,Decentralization,Banks&Banking Reform,Roads&Highways,Toll Roads,Urban Transport,Public Sector Economics&Finance,Airports and Air Services

Transmission of Gases from 20 to 33μ

In a letter to this section Dickinson and West reported a Raman shift for liquid sulfur dioxide of 524.3 cm^(-1). Bailey, Cassie and Angus interpret this as a combination band. I have found the transmission of a four inch layer of this gas for the 20.75μ quartz reststrahlen to be only 7 percent. Such strong absorption would seem more likely to be associated with a fundamental band

Investigations in the Spectral Region between 20 and 40μ

An apparatus is described which is convenient for studying the optical properties of substances with reststrahlen having wave-lengths from 6 to 150μ. A vibrationless support is described, the essential features of which are copied from the design of R. Müller but the construction is simplified. The transmission of several gases was studied with reststrahlen having wave-lengths 20 to 33μ. SO_2 shows strong absorption at 20.75μ. The reflectivity of SO_2 was tested and found to be zero at both 20.75μ and 8.7μ where it has strong absorption bands. Gas absorptions from 20 to 33μ are compared with the Raman indications. Transmissivities and reflectivities of various materials are given for the spectral region 20 to 33μ. β−MgO was found to have a reststrahlen near 23μ. Potassium iodide was found to be transparent to wave-lengths greater than 33μ

A Study of Some Aspects of Departmental Work in the Children\u27s Division of the Sunday School

Teachers in the Sunday School need to know more about the children to whom they minister. Each child must be recognized as an individual and as such, he is a candidate for the promised eternal life that Jesus promised to those who believe on His Name. How can they believe except they be sent teachers who believe on Him? Furthermore, the child is a candidate for leadership in the church in which it may at present be a member of the Children\u27s Division

Generating Revenue at Airports in the Southeastern Coastal Region of North Carolina

Airports contribute about 5% of the gross domestic product and employ over 7 million people in the United States. The purpose of this qualitative multiple-case study was to explore the strategies that airport managers need to increase nonaeronautical revenue. A generic strategy does not exist to assist airport operators in generating operating income. Aeronautical revenue does not always provide sufficient funding for airport operations and existing research does not consistently provide effective strategies for all airports to generate revenue. The sample for this qualitative multiple case study consisted of 3 small commercial airport managers in the southeastern North Carolina coastal region. The conceptual framework for this study was built upon general systems theory. The data were collected using semistructured interviews and review of company documents. Transcript review and member checking were used to strengthen credibility and trustworthiness. Through methodological triangulation of the data sources, 3 emergent themes were uncovered during a qualitative data analysis: types of nonaeronautical sources of revenue, strategies for measurement of success, and size and location of the airport. The findings from this study may contribute to social change by providing insight into strategies that contribute to sustainability at small airports. Existing and aspiring small airport managers may apply the findings to contribute to the success of the communities in which their airports reside and the local economies in which they operate