Quintessential Difficulties

An alternative to a cosmological constant is quintessence, defined as a slowly-varying scalar field potential V(\phi). If quintessence is observationally significant, an epoch of inflation is beginning at the present epoch, with \phi the slowly-rolling inflaton field. In contrast with ordinary inflation, quintessence seems to require extreme fine tuning of the potential V(\phi). The degree of fine-tuning is quantified in various cases.Comment: 7 pages LaTeX. Revised to be more pedagogical; results unchange

Stability Issues for w < -1 Dark Energy

Precision cosmological data hint that a dark energy with equation of state $w = P/\rho < -1$ and hence dubious stability is viable. Here we discuss for any $w$ nucleation from $\Lambda > 0$ to $\Lambda = 0$ in a first-order phase transition. The critical radius is argued to be at least of galactic size and the corresponding nucleation rate is glacial, thus underwriting the dark energy's stability and rendering remote any microscopic effect.Comment: 9 pages LaTeX. Significantly rewritten (including abstract

Why Have Private Saving Rates in the United States and Canada Diverged?

One of the central questions in macroeconomics for many years has been whether government policy can affect private saving rates, and if so to what extent and through what channels. The question has remained controversial because, as with other macroeconomic questions, experiments to check divergent hypotheses cannot be deliberately performed, so economists must rely upon the often dubious evidence from the limited experiments with which nature and history have endowed us. This paper discusses the results of an exceptionally good natural experiment that has been provided by Canada and the U.S. over the past thirty-five years. After moving in tandem for almost 25 years, American and Canadian private saving rates have diverged dramatically over the last decade. The primary conclusion emerging from our analysis of this phenomenon is that tax policies can have a potent impact on private savings behavior. Differences in tax structures and in the interactions of taxation and inflation appear to be important factors explaining the divergent behavior of the American and Canadian private savings rates. Recognizing the importance of asset revaluations, caused partially but not entirely by tax effects, also helps to explain the different behavior of U.S. and Canadian savings. There may also be a relationship between government deficits and the private savings differential.

The variation in pressures in the cockpit fan airplane in flight

The results of an investigation to determine the pressures in the open cockpit of a Vought VE-7 airplane are given. The observed values are small and the effect upon instruments is inconsiderable

A nonlinear encoder Technical report no. 1, 9 May - 9 Sep. 1964

Nonlinear encoder - sinusoidal reference voltage, comparator, nonlinear counter, and clock inhibit circui

The Formation of Ice upon Exposed Parts of an Airplane in Flight

In order to experimentally study the conditions leading to ice formation on aircraft surfaces, an aircraft was equipped with small auxiliary surfaces and aerodynamic shapes similar to struts, wires, Pitot heads, etc. This airplane was flown at an altitude where a temperature of 32 F was encountered, at such times as cloud formations could be found at the coincident altitude. Here it was discovered that ice formed rapidly in regard to quantity,character, shape, and rapidity of formation. An examination of this data, which confirms observations of pilots, indicates that the weight of ice collected can very possibly be sufficient to force the airplane to rapidly lose altitude on account of the increased loads. However, it is more evident that the malformation of the aerodynamic shapes may so increase the drag and reduce the lift so as to produce a loss of altitude even greater in consequence, the combination of the two working in the same direction having a double effect. Other adverse consequences are noted. The recommendation for the guidance of those who must encounter these conditions appears to lie entirely along the lines of avoidance

A study of high-speed AD and DA converters using redundancy techniques Interim report, May 10, 1963 - May 9, 1964

High speed analog-to-digital converters compared using redundancy encoding technique

Consumption Growth Parallels Income Growth: Some New Evidence

This paper argues that the versions of both permanent income and life-cycle theories which have recently become fashionable are inconsistent with the grossest features of cross-country and cross-section data on consumption and income. There is clear evidence that consumption and income growth are much more closely linked than would be predicted by these theories. it appears that consumption smoothing takes place over periods of several years not several decades. These results confirm Milton Friedman's (1957) initial view that: "The permanent income component is not to be regarded as expected lifetime earnings... It is to be interpreted as the mean income at any age regarded as permanent by the consumer unit in question, which in turn depends on its horizon and foresightedness." They call into question the usefulness of standard representative Consumer approaches to the analysis of saving behavior. And they call for increased emphasis on liquidity constraints and short run precautionary saving as determinants of consumption behavior.

An evaluation of two flat-black silicone paints for space application

Tests were conducted on two flat-black silicone paints suggested for space applications to determine their optical, electrical, and mechanical properties. Three different types of substrate materials were chosen for these paint tests; the application of the paints onto the primed substrates was carried out by spray coating. The adhesion properties were verified by thermal shock and sudden immersion into liquid nitrogen. A controlled thermal vacuum tests was also carried out by varying the temperature of the paint from -100 to 225 C. The measured optical properties included normal and hemispherical emittance, and solar absorption/reflectance. A simultaneous exposure to low-energy proton/UV irradiation in vacuum, and high-energy proton/electron irradiation was carried out. Additional tests of the paints are described