A series of thirteen original radio programs on music appreciation for students in grades five, six, and seven designed for in-school listening

Thesis (M.S.)--Boston Universit

On the unlikelihood of specific long range forces in immunologic and enzymatic reactions

In the past few years, a great many experiments have been performed by Rothen (24, 25) which he has interpreted as suggesting that antigen and antibody, and enzyme and substrate proteins, can react specifically, although separated by distances of hundreds of angstroms. This hypothesis seems to conflict with evidence accumulated from many other investigations indicating that short range interactions, involving distances usually associated with electrostatic and van der Waals’ forces, and hydrogen bonds, of the order of 5 A, operate in these reactions. We have therefore engaged in a critical analysis of the experimental techniques used by Rothen to determine whether some interpretation other than that invoking the existence of specific long range forces could be found to explain his experimental results

Laser probing of the atmosphere Semiannual status report

Light backscattering experiment in laser probing studies of atmospheric layer above 100 k

Comments on Ringwood's paper 'Petrogenesis of Apollo 11 basalts and implications for lunar origin'

Apollo 11 basalt petrogenesis and theories of lunar evolution comparing lunar and earth environment

Long distance contributions in D→VγD \to V \gamma decays

Using the factorization scheme for the nonleptonic $D \to V V_0$ weak amplitudes, we classify all diagrams which arise in $D \to V \gamma$ decays and calculate them with the help of the hybrid model which combines the heavy quark effective theory and the chiral Lagrangian approach. Thus we determine the long distance contribution to the amplitudes of Cabibbo allowed and Cabibbo suppressed $D \to V\gamma$ decays. The calculation of the expected range of the branching ratios of nine different $D \to V \gamma$ channels is compared with results of other approaches. The present work establishes an increase of the parity violating contribution in these decays in comparison with previous analyses.Comment: 15 pages, latex, 2 figures; we have changed Table 2 and the caption of Table 1. To be published in Eur. Phys.

Phobos and Deimos: A base for sampling the Martian past

Future exploration of Mars is summed up by the proposal that the Martian satellites provide an ideal base for exploring the surface of Mars. For example, a manned base on Deimos could direct a series of unmanned rovers and sample recovery operations, providing an immediate feedback to the operation. Samples analyzed in such an environment would be fresh, and most importantly, would not require quarantine

Magnification of starting torques of dc motors by maximum power point trackers in photovoltaic systems

Direct current (dc) motors are used in terrestrial photovoltaic (PV) systems such as in water-pumping systems for irrigation and water supply. Direct current motors may also be used for space applications. Simple and low weight systems including dc motors may be of special interest in space where the motors are directly coupled to the solar cell array (with no storage). The system will operate only during times when sufficient insolation is available. An important performance characteristic of electric motors is the starting to rated torque ratio. Different types of dc motors have different starting torque ratios. These ratios are dictated by the size of solar cell array, and the developed motor torque may not be sufficient to overcome the load starting torque. By including a maximum power point tracker (MPPT) in the PV system, the starting to rated torque ratio will increase, the amount of which depends on the motor type. The starting torque ratio is calculated for the permanent magnet, series and shunt excited dc motors when powered by solar cell arrays for two cases: with and without MPPT's. Defining a motor torque magnification by the ratio of the motor torque with an MPPT to the motor torque without an MPPT, a magnification of 3 was obtained for the permanent magnet motor and a magnification of 7 for both the series and shunt motors. The effect of the variation of solar insolation on the motor starting torque was covered. All motor types are less sensitive to insolation variation in systems including MPPT's as compared to systems with MPPT's. The analysis of this paper will assist the PV system designed to determine whether or not to include an MPPT in the system for a specific motor type