The gender earnings gap: evidence from the UK

Rising female labour-force participation has been one of the most striking changes to have occurred in industrialised countries’ labour markets over recent decades. In the UK between 1973 and 1993, female labour-force participation rose from 57 per cent to 68 per cent for women aged 16 to 64.2 Women now account for half of all employees and 36 per cent of those working full-time (compared with 38 per cent and 30 per cent respectively in 1971).3 Yet, although women have been the main beneficiaries from the creation of new jobs, they have still not gained earnings parity with men. For women working full-time,however, the pay gap has been closing, and the New Earnings Survey reports a rise in the ratio of median hourly pay of full-time women to men from 65 per cent in 1970 to 73 per cent in 1976 and a more gradual increase thereafter to 80 per cent in 1994. In contrast, the relative earnings position of women working part-time has changed little for over two decades. Our period of study (the mid-1970s to the early 1990s) saw significant shifts in the composition of female employment that are potentially important in explaining changes in the gender gap. First, there has been a notable increase in the average age of full-time working women which has primarily resulted from increased employment amongst women of child-bearing age. This has shifted the

Development of a switchable system for longitudinal and longitudinal-torsional vibration extraction

High-frequency/low-frequency drilling is an attractive technology for planetary exploration tools, and one which has seen considerable innovation in the techniques used to ensure rotation of the front-end cutting bit. This rotation is essential to prevent tooth imprintation in hard materials, and extracting the rotation from the high-frequency or ultrasonic system has obvious benefits in terms of simplicity and robustness. However, extracting the rotation from an ultrasonic horn raises the possibility of bit-walk if it is used to operate a coring device and the authors therefore propose an ultrasonic horn which uses an excitation applied to a single input surface to yield torsional and longitudinal vibration on two physically separated output surfaces. By engaging with the two output surfaces, longitudinal vibration can be extracted to achieve initial percussive drilling, even where a coring bit is applied, and the torsional output can subsequently be added to prevent tooth imprintation once the coring bit has settled into the site in question. In this manner, the horn provides a mechanism whereby high-frequency/low-frequency drilling technique can be applied to coring operations without the need for an exceptionally robust drill structure capable of resisting bit-walk forces

Optimisation of an ultrasonic drill horn for planetary subsurface sample retrieval

Ultrasonic tools can cut through foodstuffs, biological material and other soft matter with relative ease. However, when attempts are made to cut through harder material, the rate of progress markedly declines. Under such circumstances it is sometimes necessary to reduce the frequency of the blows delivered to the target, in order to ensure that each blow exceeds the compressive strength of the material, but for space applications the small size of high-frequency ultrasonic horns is extremely attractive. This paper therefore considers the optimization of horns for exploitation of the high-frequency/low-frequency drilling technique, whereby a free-mass oscillating between the horn and the target is employed to reduce the frequency at which impulse events are delivered to the target

Evaluation program for secondary spacecraft cells: initial evaluation tests of 20.0 ampere-hour nickel-cadmium spacecraft cells manufactured by Gulton Industries, Incorporated

The report describes testing and performance of 20.0 ampere-hour Ni-Col spacecraft batteries

Evaluation program for secondary spacecraft cells - Acceptance test of Sonotone Corporation 20 ampere-hour nickel-cadmium cells

Acceptance tests of 20 ampere-hour sealed nickel-cadmium secondary spacecraft cell

Initial evaluation tests of Eagle-Picher Industries 9.0 ampere-hour nickel-cadmium spacecraft cells for the heat capacity mapping mission satellite and the stratospheric aerosol and gas experiment satellite

The results of tests to insure that all cells put into the life cycle program are of high quality are reported. The tests consisted of the following: phenolptalein leak tests, internal short test, charge efficiency test, and overcharge tests. The results of tests for 10 cells are tabulated

Evaluation Program for Secondary Spacecraft Cells: Initial Evaluation Tests of General Electric Company 6.0 Ampere Hour Nickel Cadmium Spacecraft Cells for the Dynamic Explorer Satellite Program

Evaluation tests of 10 nickel cadmium cells are described. Although pressures were greater than what normally was exhibited by General Electric cells in the past, it is recommended that these cells be placed on life test simulating the predicted Dynamic Explorer flight profiles

The GEOS-2 heat pipe system and its performance in test and orbit

GEOS 2 satellite heat transfer pipe performance in test and orbi

Initial evaluation tests of General Electric Company 26.5 ampere-hour nickel-cadmium spacecraft cells with auxiliary electrodes for the TIROS-N and NOAA-A satellites

This evaluation test program had the purpose to insure that all cells put into the life cycle program are of high quality by the screening of cells found to have electrolyte leakage, internal shorts, low capacity, or inability of any cell to recover its open-circuit voltage above 1.150 volts during the internal short test. Test limits specify those values at which a cell is to be terminated from charge or discharge. Requirements are referenced to as normally expected values based on past performance of aerospace nickel-cadmium cells with demonstrated life characteristics. A requirement does not constitute a limit for discontinuance from test

Evaluation program for secondary spacecraft cells: Initial evaluation tests of General Electric Company 40.0 ampere-hour nickel-cadmium spacecraft cells for the tracking data relay satellite system

Five cells provided by NASA's Goddard Space Flight Center were evaluated at room temperature and pressure (25 C plus or minus 2 C) with discharges at the 2 hour rate. Measurements of the cell containers following test, indicated an average increase of .006 inches at the plate thickness. Average end of charge voltages and pressures, and capacity output in ampere hours were determined. Three cells exceeded the voltage requirements of 1.52 volts during both c/10 charges at 20 C. All cells exceeded the voltage requirement of 1.52 volts during the 0 C overcharge test, although their end charges were below 1.50 volts. The pressure requirement of 65 psia was exceeded by both pressure transducer cells during c/10 charges at 25 C and 20 C and also during the 0 C overcharge test. The cells with pressure transducers reached a pressure of 20 psia before reaching the voltage limit of 1.550 volts during the pressure versus capacity test, and exhibited a pressure decay of 2 psia during the last 30 minutes of the 1 hour open circuit stand. Average capacity was 51.3 ampere hours