The November 1987 eclipse of the zeta-Aur system HR 2554

It is confirmed that HR 2554 (G6 II + A0 V) is an atmospheric eclipsing system of the zeta-Aur type. The IUE observations of the Nov. 1987 eclipse indicate that the eclipse of the A star lasts 4 days and is not total. Absorption lines due to the extended atmosphere of the primary can be seen a day before and after the eclipse and are missing 2 days from first and 4th contact. Thus the outer envelope of the primary extends to less than 1 stellar radius beyond the photosphere. Compared to 22 Vul (G3 Ib-II + B9 V), where the absorption can be traced to a few stellar radii, HR 2554 is a more moderate case of mass outflow, which implies there is reduced interaction of the secondary within the wind from the primary as is seen in the other zeta-Aur systems

Excess noise in Pb(1-x)Sn(x)Se semiconductor lasers

The noise characteristics of the TDL were studied for frequencies less than 20 kHz. For heterodyne applications, the high frequency ( 1 MHz) characteristics are also important. Therefore, the high frequency noise characteristics of the TDL were studied as a part of a full TDL characterization program which has been implemented for the improvement of the TDL as a local oscillator in the LHS system. It was observed that all the devices showed similar high frequency noise characteristics even though they were all constructed using different techniques. These common high frequency noise characteristics are reported

The growth of textile factories in Derbyshire during the eighteenth century

Not Availabl

Soil and water conservation in Kenya: Report of a Workshop held at the Univeristy of Naibori 21- 23 September, 1977

A Workshop on Soil and Water Conservation was held at the University of Nairobi from 2l to 23 September 1977, sponsored by the Land and Farm Management Division of the Ministry of Agriculture and the Departments of Agricultural Engineering of the University and Egerton College. The objectives of this workshop were:- 1. To bring together research workers, teachers, extension officers and others who are concerned with problems of soil and water conservation, 2. To exchange technical information and discuss problems in assessing needs and in planning, implementing and evaluating conservation systems, and 3. To identify priorities for research and to seek ways to increase the effectiveness and relevance of teaching. In keeping with these objectives, a number of papers were presented at the workshop and are included in full in this report. Topics covered include, among others, experiments with various cropping systems and tillage methods to determine which patterns of land use minimise soil loss methods for reclaiming swampy or badly eroding land, studies of small experimental catchment areas, the physical and social problems involved in carrying out conservation programmes in semi-arid areas, and the Ministry of Agriculture's plans for a major soil and water conservation programme. In addition to these discussions, field trips were conducted to Machakos and Murang'a which are described in this report, and a list of recommendations was drafted which is also included