Understanding Legislator Experiences of Family-Friendly Working Practices in Political Institutions

This is a post-peer-review, pre-copy edit version of an article published in Politics and Gender. © 2015, Cambridge University Press

Evaluation of a series hybrid thrust bearing at DN values to three million. 2: Fabrication and testing

Results of tests made to determine the experimental performance of a series hybrid bearing are reported. The bearing consists of a 150 mm ball bearing and a centrifugally actuated, conical, fluid film bearing fitting an envelope with an outer radius of 86.4 mm (3.4 in.) and inner radius of 71 mm (2.8 in.). Tests were conducted up to 16,500 rpm, at which speed an axial load of 15,568 N (3500 lb) was safely supported by the hybrid bearing system. Through the employment of the series hybrid bearing principle, it was possible to reduce the effective ball bearing speed to approximately one-half of the shaft speed. A reduction of this magnitude should result in a tenfold increase in the ball bearing fatigue life. A successful simulation of fluid film bearing lubricant supply failure, performed repeatedly at an operating speed of 10,000 rpm, resulted in complete and smooth change over to full scale ball bearing operation when the oil supply to the fluid film bearing was discontinued. Reactivation of the fluid film supply system produced a flawless return to the original mode of hybrid operation

Line-profile tomography of exoplanet transits I: The Doppler shadow of HD 189733b

We present a direct method for isolating the component of the starlight blocked by a planet as it transits its host star, and apply it to spectra of the bright transiting planet HD 189733b. We model the global shape of the stellar cross-correlation function as the convolution of a limb-darkened rotation profile and a gaussian representing the Doppler core of the average photospheric line profile. The light blocked by the planet during the transit is a gaussian of the same intrinsic width, whose trajectory across the line profile yields a precise measure of the misalignment angle and an independent measure of v sin I. We show that even when v sin I is less than the width of the intrinsic line profile, the travelling Doppler "shadow" cast by the planet creates an identifiable distortion in the line profiles which is amenable to direct modelling. Direct measurement of the trajectory of the missing starlight yields self-consistent measures of the projected stellar rotation rate, the intrinsic width of the mean local photospheric line profile, the projected spin-orbit misalignment angle, and the system's centre-of-mass velocity. Combined with the photometric rotation period, the results give a geometrical measure of the stellar radius which agrees closely with values obtained from high-precision transit photometry if a small amount of differential rotation is present in the stellar photosphere.Comment: 8 pages, 5 figures, 2 tables; accepted by MNRA

Complex Variability of the Hα\alpha Emission Line Profile of the T Tauri Binary System KH 15D: The Influence of Orbital Phase, Occultation by the Circumbinary Disk, and Accretion Phenomenae

We have obtained 48 high resolution echelle spectra of the pre-main sequence eclipsing binary system KH~15D (V582 Mon, P = 48.37 d, $e$ $\sim$ 0.6, M$_{A}$ = 0.6 M$_{\odot}$, M$_{B}$ = 0.7 M$_{\odot}$). The eclipses are caused by a circumbinary disk seen nearly edge on, which at the epoch of these observations completely obscured the orbit of star B and a large portion of the orbit of star A. The spectra were obtained over five contiguous observing seasons from 2001/2002 to 2005/2006 while star A was fully visible, fully occulted, and during several ingress and egress events. The H$\alpha$ line profile shows dramatic changes in these time series data over timescales ranging from days to years. A fraction of the variations are due to "edge effects" and depend only on the height of star A above or below the razor sharp edge of the occulting disk. Other observed variations depend on the orbital phase: the H$\alpha$ emission line profile changes from an inverse P Cygni type profile during ingress to an enhanced double-peaked profile, with both a blue and red emission component, during egress. Each of these interpreted variations are complicated by the fact that there is also a chaotic, irregular component present in these profiles. We find that the complex data set can be largely understood in the context of accretion onto the stars from a circumbinary disk with gas flows as predicted by the models of eccentric T Tauri binaries put forward by Artymowicz & Lubow, G\"{u}nther & Kley, and de Val-Borro et al. In particular, our data provide strong support for the pulsed accretion phenomenon, in which enhanced accretion occurs during and after perihelion passage.Comment: accepted to Ap

The Light Curve of the Weakly-Accreting T Tauri Binary KH 15D from 2005-10: Insights into the Nature of its Protoplanetary Disk

Photometry of the unique pre-main sequence binary system KH 15D is presented, spanning the years 2005-2010. This system has exhibited photometric variations and eclipses over the last 50 years caused by a precessing circumbinary disk. Advancement of the occulting edge across the binary orbit has continued and the photospheres of both stars are now completely obscured at all times. The system is now visible only by scattered light, and yet it continues to show a periodic variation on the orbital cycle with an amplitude exceeding two magnitudes. This variation, which depends only on the binary phase, has likely been present in the data since at least 1995. It can, by itself, account for shoulders on the light curve prior to ingress and following egress, obviating the need for components of extant models such as a scattering halo around star A or forward scattering from a fuzzy disk edge. A plausible source for the variable scattering component is reflected light from the far side of a warped occulting disk. We have detected color changes in V-I of several tenths of a magnitude to both the blue and red that occur during times of minima. These may indicate the presence of a third source of light (faint star) within the system, or a change in the reflectance properties of the disk as the portion being illuminated varies with the orbital motion of the stars. The data support a picture of the circumbinary disk as a geometrically thin, optically thick layer of perhaps mm or cm-sized particles that has been sculpted by the binary stars and possibly other components into a decidedly nonplanar configuration. A simple (infinitely sharp) knife-edge model does a good job of accounting for all of the recent (2005-2010) occultation data.Comment: To appear in The Astronomical Journa

Evaluation of a series hybird thrust bearing at DN values to three million. 1: Analysis and design

The analysis and design are presented of a hybrid bearing consisting of a 150-mm ball bearing and a centrifugally actuated, conical, fluid film bearing fitting an envelope with an outer radius of 86.4 mm (3.4 in.) and an inner radius of 71 mm (2.8 in.). The bearing analysis, combined with available torque data on ball bearings, indicates that an effective speed split between the ball and fluid-film bearings of 50 percent may be expected during operation at 20,000 rpm and under an axial load of 17,800 newtons (4000 lbs.). This speed split can result in a ten-fold increase in the life of the ball bearing when compared to a simple ball bearing system operating under similar conditions

Design and evaluation of a 3 million DN series-hybrid thrust bearing

The bearing, consisting of a 150-mm ball bearing and a centrifugally actuated, conical, fluid-film bearing, was fatigue tested. Test conditions were representative of a mainshaft ball bearing in a gas turbine engine operating at maximum thrust load to simulate aircraft takeoff conditions. Tests were conducted up to 16000 rpm and at this speed an axial load of 15568 newtons (3500 lb) was safely supported by the hybrid bearing system. Through the series-hybrid bearing principle, the effective ball bearing speed was reduced to approximately one-half of the shaft speed. It was concluded that a speed reduction of this magnitude results in a ten-fold increase in the ball bearing fatigue life. A successful evaluation of fluid-film bearing lubricant supply failure was performed repeatedly at an operating speed of 10,000 rpm. A complete and smooth changeover to full-scale ball bearing operation was effected when the oil supply to the fluid-film bearing was cut off. Reactivation of the fluid-film oil supply system resulted in a flawless return to the original mode of hybrid operation

Binning is sinning: morphological light-curve distortions due to finite integration time

We explore how finite integration times or equivalently temporal binning induces morphological distortions to the transit light-curve. These distortions, if uncorrected for, lead to the retrieval of erroneous system parameters and may even lead to some planetary candidates being rejected as ostensibly unphysical. We provide analytic expressions for estimating the disturbance to the various light-curve parameters as a function of the integration time. These effects are particularly crucial in light of the long-cadence photometry often used for discovering new exoplanets by, for example, Convection Rotation and Planetary Transits (COROT) and the Kepler Mission (8.5 and 30 min). One of the dominant effects of long integration times is a systematic underestimation of the light-curve-derived stellar density, which has significant ramifications for transit surveys. We present a discussion of numerical integration techniques to compensate for the effects and produce expressions to quickly estimate the errors of such techniques, as a function of integration time and numerical resolution. This allows for an economic choice of resolution before attempting fits of long-cadence light-curves. We provide a comparison of the short- and long-cadence light-curves of TrES-2b and show that the retrieved transit parameters are consistent using the techniques discussed here.Comment: Long delayed upload of the MNRAS accepted version, 10 pages, 3 figure

The association of shift work and coronary heart disease risk factors among male factory workers in Kota Bharu, Kelantan

Shift work is one of the work hour systems in which a relay of employees extends the period of production beyond the conventional 8-hour working day. It has been found to be associated with various health problems and there is concern that shift workers are at higher risk to develop risk factors for coronary heart disease (CHD). The study was undertaken to examine relationships between shift work and CHD risk factors, namely hypertension, dyslipidaemia (either hypercholesterolaemia, hyper-low density lipoprotein-cholesterolaemia, hypo-high density lipoprotein-cholesterolaemia or hypertriglyceridaemia), high body mass index (BMI), hyperglycemia and physical inactivity among male factory workers in a factory in Kota Bharu, Kelantan. METHODS: This study was a contrived cross-sectional study of 76 shift and 72 day workers from one ofthe factories in Kota Bharu, Kelantan. Data was collected through a questionnaire on psychosocial and life-style factors, anthropometric and blood pressure measurement, fasting blood sugar and fasting lipid proJiles analyses. RESULTS: The prevalence of hypertension, hypercholesterolaemia, hypertriglyceridaemia and high body mass index (BMO were significantly higher among shift workers compared to day workers. There was no difference in the prevalence of hyperg[ycemia, hypo-high-density lipoprotein-cholesterolaemia, hyper-high-density lipoprotein-cholesterolaemia and physical inactivity. When the shiji workers were compared with the day workers, the aajusted odds ratio (OR) for hypertension, high BMI andphysical inactivity were 9.1 (95% CI 1.4-56.8), 2.9 (95% CI 1.3-6.1) and 7.7 (95% CI 2.1-27.5) respectively. There was neither association of shift work with dyslipidaemia, nor with hyperglycemia. CONCLUSIONS: There were positive association between shiji work and hypertension, high BMI andphysical inactivity which denotes a higher risk of CHD risk factors among shift workers compared to day workers

The spin-orbit angle of the transiting hot jupiter CoRoT-1b

We measure the angle between the planetary orbit and the stellar rotation axis in the transiting planetary system CoRoT-1, with new HIRES/Keck and FORS/VLT high-accuracy photometry. The data indicate a highly tilted system, with a projected spin-orbit angle lambda = 77 +- 11 degrees. Systematic uncertainties in the radial velocity data could cause the actual errors to be larger by an unknown amount, and this result needs to be confirmed with further high-accuracy spectroscopic transit measurements. Spin-orbit alignment has now been measured in a dozen extra-solar planetary systems, and several show strong misalignment. The first three misaligned planets were all much more massive than Jupiter and followed eccentric orbits. CoRoT-1, however, is a jovian-mass close-in planet on a circular orbit. If its strong misalignment is confirmed, it would break this pattern. The high occurence of misaligned systems for several types of planets and orbits favours planet-planet scattering as a mechanism to bring gas giants on very close orbits.Comment: to appear in in MNRAS letters [5 pages