Jig protects transistors from heat while tinning leads

In tinning transistor leads, an aluminum jig is used to dip the leads into the molten tin. The jigs mass shunts excess heat given off by the molten tin before it reaches and damages the transistor body

Gas core rocket reactors - A new look

Feasibility analysis of open-cycle gas-core nuclear rocket engin

Cost and benefits of rent control in Kumasi, Ghana

Over the past forty years, rent control has been a feature of housing in Ghana. This study focusses on the housing market in Kumasi, the second largest city in Ghana. The authors examine the characteristics of the rent control regime in force there, and assess the costs and benefits of rent control, on landlords and on tenants, and its effect on the housing stock. Rent control has been successful in ensuring that housing is very inexpensive for most households, in both absolute terms and in the proportion of income devoted to rent. Thesecontrols have deprived landlords of economic returns on their property, causing them to withdraw stock from renting to use for their own family members and to reduce maintenance. However, rent control is not the only constraint on the housing market, in Kumasi or in Ghana. The paper also describes other supply side and regulatory constraints; such as those affecting land, finance, and choice of building design and materials. A number of options for relaxation/decontrol are studied with the aid of a simple present value model. Along with decontrol of new construction it is recommended that floating up and out of controls over a five year period should be considered, along with policy changes to ensure ready supplies of land, finance, and building materials. Such policies are essential, given that private housing investment provides the great majority of rooms in Ghanaian urban areas.Non Bank Financial Institutions,Banks&Banking Reform,Housing Finance,Housing&Human Habitats,Economic Theory&Research

Thermal and Non-thermal Plasmas in the Galaxy Cluster 3C 129

We describe new Chandra spectroscopy data of the cluster which harbors the prototypical "head tail" radio galaxy 3C 129 and the weaker radio galaxy 3C 129.1. We combined the Chandra data with Very Large Array (VLA) radio data taken at 0.33, 5, and 8 GHz (archival data) and 1.4 GHz (new data). We also obtained new HI observations at the Dominion Radio Astrophysical Observatory (DRAO) to measure the neutral Hydrogen column density in the direction of the cluster with arcminute angular resolution. The Chandra observation reveals extended X-ray emission from the radio galaxy 3C 129.1 with a total luminosity of 1.5E+41 erg/s. The X-ray excess is resolved into an extended central source of ~2 arcsec (1 kpc) diameter and several point sources with an individual luminosity up to 2.1E+40 erg/s. In the case of the radio galaxy 3C 129, the Chandra observation shows, in addition to core and jet X-ray emission reported in an earlier paper, some evidence for extended, diffuse X-ray emission from a region east of the radio core. The 12 arcsec x 36 arcsec (6 kpc x 17 kpc) region lies "in front" of the radio core, in the same direction into which the radio galaxy is moving. We use the radio and X-ray data to study in detail the pressure balance between the non-thermal radio plasma and the thermal Intra Cluster Medium (ICM) along the tail of 3C 129 which extends over 15 arcmin (427 kpc). Depending on the assumed lower energy cutoff of the electron energy spectrum, the minimum pressure of the radio plasma lies a factor of between 10 and 40 below the ICM pressure for a large part of the tail. We discuss several possibilities to explain the apparent pressure mismatch.Comment: Accepted for publication in MNRAS. Refereed manuscript. 14 pages, 8 figures, additional panel of Fig. 3 shows asymmetric ICM distributio

A Quarter Century, Not a Raised Voice

This dedication was in recognition of Wilbert D. Ham’s retirement from the University of Kentucky College of Law faculty. Wilber D. Ham served on the faculty from 1949 until 1986

First detection of phase-dependent colliding wind X-ray emission outside the Milky Way

After having reported the detection of X-rays emitted by the peculiar system HD5980, we assess here the origin of this high-energy emission from additional X-ray observations obtained with XMM-Newton. This research provides the first detection of apparently periodic X-ray emission from hot gas produced by the collision of winds in an evolved massive binary outside the Milky Way. It also provides the first X-ray monitoring of a Luminous Blue Variable only years after its eruption and shows that the dominant source of the X-rays is not associated with the ejecta.Comment: 13 pages, 3 figures and 1 table, accepted for publication in ApJ (letters

Cosmic X-ray background and Earth albedo Spectra with Swift/BAT

We use Swift/BAT Earth occultation data at different geomagnetic latitudes to derive a sensitive measurement of the Cosmic X-ray background (CXB) and of the Earth albedo emission in the 15--200 keV band. We compare our CXB spectrum with recent (INTEGRAL, BeppoSAX) and past results (HEAO-1) and find good agreement. Using an independent measurement of the CXB spectrum we are able to confirm our results. This study shows that the BAT CXB spectrum has a normalization ~8(+/-3)% larger than the HEAO-1 measurement. The BAT accurate Earth albedo spectrum can be used to predict the level of photon background for satellites in low Earth and mid inclination orbits.Comment: Accepted for publication in the Astrophysical Journal. 38 Pages, 16 Figures, 2 Table

Justice (Vol. 47, Iss. 15)

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