Trigonometric Parallaxes for 1,507 Nearby Mid-to-Late M-dwarfs

The MEarth survey is a search for small rocky planets around the smallest, nearest stars to the Sun as identified by high proper motion with red colors. We augmented our planetary search time series with lower cadence astrometric imaging and obtained two million images of approximately 1800 stars suspected to be mid-to-late M dwarfs. We fit an astrometric model to MEarth's images for 1507 stars and obtained trigonometric distance measurements to each star with an average precision of 5 milliarcseconds. Our measurements, combined with the 2MASS photometry, allowed us to obtain an absolute K_s magnitude for each star. In turn, this allows us to better estimate the stellar parameters than those obtained with photometric estimates alone and to better prioritize the targets chosen to monitor at high cadence for planetary transits. The MEarth sample is mostly complete out to a distance of 25 parsecs for stars of type M5.5V and earlier, and mostly complete for later type stars out to 20 parsecs. We find eight stars that are within ten parsecs of the Sun for which there did not exist a published trigonometric parallax distance estimate. We release with this work a catalog of the trigonometric parallax measurements for 1,507 mid-to-late M-dwarfs, as well as new estimates of their masses and radii.Comment: ApJ, accepted. 36 pages, 8 figures, 2 tables. Please find our data table here: http://www.cfa.harvard.edu/MEarth/DataDR2.htm

Galvanic corrosion of aluminium–copper model alloys

Galvanic coupling between different α and θ phase-containing model Al–Cu alloys, deposited by magnetron sputtering, has revealed that the anodic α phase did not suffer corrosion and remained in the passive state in sulphate solution. Conversely, sulphate ions induced pitting of the cathodic θ phase. Pitting susceptibility of the cathode increased when the difference between the copper content of the anode and cathode increased. Similar observations were made for all the galvanic couples; further, the higher the copper content of a phase, then the greater its susceptibility to pitting

Influence of humidity and wind on heat loads within dairy barns.

This bulletin is a report on Department of Agricultural Engineering Research Project 66, 'Climatic Laboratories'--P. [2].Digitized 2007 AES.Includes bibliographical references (page 28)

The rotation and Galactic kinematics of mid M dwarfs in the Solar Neighborhood

Rotation is a directly-observable stellar property, and drives magnetic field generation and activity through a magnetic dynamo. Main sequence stars with masses below approximately 0.35Msun (mid-to-late M dwarfs) are fully-convective, and are expected to have a different type of dynamo mechanism than solar-type stars. Measurements of their rotation rates provide insights into these mechanisms, but few rotation periods are available for these stars at field ages. Using photometry from the MEarth transit survey, we measure rotation periods for 387 nearby, mid-to-late M dwarfs in the Northern hemisphere, finding periods from 0.1 to 140 days. The typical detected rotator has stable, sinusoidal photometric modulations at a semi-amplitude of 0.5 to 1%. We find no period-amplitude relation for stars below 0.25Msun and an anti-correlation between period and amplitude for higher-mass M dwarfs. We highlight the existence of older, slowly-rotating stars without H{\alpha} emission that nevertheless have strong photometric variability. The Galactic kinematics of our sample is consistent with the local population of G and K dwarfs, and rotators have metallicities characteristic of the Solar Neighborhood. We use the W space velocities and established age-velocity relations to estimate that stars with P<10 days are on average <2 Gyrs, and that those with P>70 days are about 5 Gyrs. The period distribution is mass dependent: as the mass decreases, the slowest rotators at a given mass have longer periods, and the fastest rotators have shorter periods. We find a lack of stars with intermediate rotation periods. [Abridged]Comment: Accepted to ApJ. Machine readable tables and additional figures are available in the published article or on reques

INVESTIGATING THE APPLICATION OF SERVICE MODULARISATION IN AN INDUSTRY: - “A CASE STUDY OF A MOBILE OPERATOR IN SIERRA LEONE (AIRTEL) AND A MONEY TRANSFER SERVICE IN THE UNITED KINGDOM (WESTERN UNION)”

Abstract There is an increasing trend in the need for services, and organisations are now moving towards modularisation of their services for efficiency, competitive advantage and to satisfy their customers. Modularisation activities focuses on standardisation, customisation and the reduction of complexity in its system to achieve efficiency, cost minimisation and better service for business growth. The main objective of this study is to examine how theory and practice relates; which involves bringing out concepts of modularity from literatures and examine practical cases in the service industry. Interest in the field of modularity is emerging, in order to discover how the implementation of modularity can add value to research and practical application. Therefore, this dissertation seeks to arrive at strategic decisions that should be considered in the implementation of modularisation and identifying the factors that influences the implementation of modularisation in a money transfer service. To achieve this, two case studies were selected, a Mobile Money Transfer Service System in Sierra Leone and the Western Union Money Transfer Service in the United Kingdom. According to the results the application of modularisation in a service organisation can enhance service efficiency, customers’ satisfaction and contributes greatly in business development by gaining competitive advantage and increase in profit