Study of bonding between glass and plastic in glass-reinforced plastics - Extended work Quarterly progress report, 1 Jan. - 31 Mar. 1967

Procedures for fluorination and alkylation of glass fabric for subsequent use in production of laminate

Letter from D. Chamberlain & Co. to James B. Finley

An advertisement for a new hotel in Boston -- Adams House. Abstract Number - 506https://digitalcommons.owu.edu/finley-letters/1704/thumbnail.jp

Land pressures, the evolution of farming systems, and development strategies in Africa: A synthesis

AbstractEvidence assembled in this special issue of Food Policy shows that rising rural population densities in parts of Africa are profoundly affecting farming systems and the region’s economies in ways that are underappreciated in current discourse on African development issues. This study synthesizes how people, markets and governments are responding to rising land pressures in Africa, drawing on key findings from the various contributions in this special issue. The papers herein revisit the issue of Boserupian agricultural intensification as an important response to land constraints, but they also go further than Boserup and her followers to explore broader responses to land constraints, including non-farm diversification, migration, and reduced fertility rates. Agricultural and rural development strategies in the region will need to more fully anticipate the implications of Africa’s rapidly changing land and demographic situation, and the immense challenges that mounting land pressures pose in the context of current evidence of unsustainable agricultural intensification, a rapidly rising labor force associated with the region’s current demographic conditions, and limited nonfarm job creation. These challenges are manageable but will require explicit policy actions to address the unique development challenges in densely populated rural areas

Parallel implementation of a single assignment language

High level computer programming language /SAMPLE/ and parallel processing system to implement i

Effect of uniaxial stress on gallium, beryllium, and copper-doped germanium hole population inversion lasers

The effects of stress on germanium lasers doped with single, double, and triple acceptors have been investigated. The results can be explained quantitatively with theoretical calculations and can be attributed to specific changes in the energy levels of acceptors in germanium under stress. In contrast to previous measurements, gallium-doped Ge crystals show a decrease in lasing upon uniaxial stress. The decrease seen here is attributed to the decrease in heavy hole effective mass upon application of uniaxial stress, which results in a decreased population inversion. The discrepancy between this work and previous studies can be explained with the low compensation level of the material used here. Because the amount of ionized impurity scattering in low-compensated germanium lasers is small to begin with, the reduction in scattering with uniaxial stress does not play a significant role in changing the laser operation. Beryllium-doped germanium lasers operate based on a different mechanism of population inversion. In this material it is proposed that holes can transfer between bands by giving their energy to a neutral beryllium atom, raising the hole from the ground to a bound excited state. The free hole will then return to zero energy with some probability of entering the other band. The minimum and maximum E/B ratios for lasing change with uniaxial stress because of the change in effective mass and bound excited state energy. These limits have been calculated for the case of 300 bar [100] stress, and match very well with the observed data. This adds further credence to the proposed mechanism for population inversion in this material. In contrast to Be and Ga-doped lasers, copper-doped lasers under uniaxial stress show an increase in the range of E and B where lasing is seen. To understand this change the theoretical limits for population inversion based on both the optical phonon mechanism and the neutral acceptor mechanism have been calculated. The data are described by population inversion via optical phonons at zero pressure. However, both mechanisms most likely occur when the slightly higher, non-uniform pressures of 300 bar are applied, leading to an increase in population inversion and lasing. Upon further increasing the pressure to 600 bar, the limits for population inversion decrease and a decrease in the lasing is seen