Mismatching Measures of Output and Prices: Implications for Measuring the Comovement of Prices and Output

price output correlation

A Simple Derivation of the Equation for Mean Free Path

According to simple kinetic theory, in which all the gas molecules but one are considered stationary, the mean free path L is given by L = 1/N π σ2 , where N is the number of molecules per cc. and σ is the molecular diameter. Clausius, considering all molecules to be moving with the mean relative velocity, finds L = 3/4N π σ2. Again, Maxwell, applying his law of velocity distribution, obtains the result L= 1/√2N π σ2. This value found by Maxwell is the one most generally accepted. If we consider it to be correct, then the value from simple kinetic theory is 41% too large, while that found by Clausius is 6% too large. An approximate value of L, much more nearly correct than the first one given, may be derived very simply by considering the gas molecules to be vibrating in sheets. The result obtained is L = 1/ 4 N σ2. This value is 11% higher than that found by Maxwell, as compared to 41% for the first value given above. The mathematical difficulties encountered by Clausius and Maxwell in deriving their formulas are entirely avoided in this development

Correlation of Neatness and Scholarship in Physics

353 reports, written by 33 students in three laboratory sections of junior physics, were graded as to neatness. The average neatness grade and the term laboratory grade for each student were used in a correlation study. For each of the three laboratory sections the correlation coefficient was positive. The coefficient for all 33 students was + 0.27. Although the number of students graded was small, we may conclude that in general we may expect neatness and high grades in physics to be associated. Exceptions to the rule and a low correlation coefficient both definitely indicate that neatness of written reports cannot alone be relied upon as an index of scholarship in physics

Coefficients of Diffusion of Salt Vapors in the Bunsen Flame

The coefficients of diffusion of alkali salts in the Bunsen flame have been determined by a photographic method which is a modification of the method used by H. A. Wilson. The values of the diffusion coefficients obtained for sodium, potassium, and caesium salts are roughly proportional to the reciprocals of the atomic weights of the metals. This is what we should expect from kinetic theory, if we consider the luminosity to be due to free metal atoms in the flame. Lithium salts, however, are found to have a lower coefficient of diffusion than sodium salts, and hence their metal atoms are probably free only a part of the time the vapor is in the flame

A New Analysis of the Action of Amsler\u27s Polar Planimeter

The theory of Amsler\u27s polar planimeter, as commonly given, leads to the expression A= L h, where A is the area circumscribed, L is the length of the tracer arm, and h is the net distance of translation of the tracer arm in a direction perpendicular to its length. However, it can be shown that the area may also be given by A = L 2 ∅, where ∅ is the net angle through which the tracer arm has rotated about either of its ends. But as the tracer point passes around the area A, the tracer arm does not, in general, rotate simply about one end. At any particular instant it rotates about some point which may be situated anywhere along its length. However, about whatever single point the arm may be rotating, such rotation can be resolved into two simultaneous rotations about the two ends. Therefore for purposes of analysis we may consider that the tracer arm rotates only about the ends, and we may express the area in terms of that rotation, as already stated

The Spectral Distribution of Erythemal Effectiveness of Ultraviolet Radiation

During the last twelve years several determinations of the distribution of erythemal effectiveness of radiation in the spectral region extending from wave-length 2400 or 2500 A. to about 3400 A. have indicated maximal effectiveness at 2967 A. However, all the investigators using monochromatic radiation employed the mercury vapor arc as source, so that their observations necessarily were limited to those wave-lengths represented by fairly intense lines of the mercury arc spectrum. These lines are not close enough together to allow accurate determination of the curve of erythemal effectiveness. Maximal effectiveness was assumed to be at 2967 A., its spectral position being roughly indicated by measurements at that wave-length and at wave-lengths no closer than 2925 and 3024 A

Alien Registration- Davis, George E. (Old Town, Penobscot County)

https://digitalmaine.com/alien_docs/5957/thumbnail.jp

A Spectrophotometric Method of Studying Hemoglobin and Other Colored Substances in Solution

An investigation was carried out to determine the possibilities of applying spectrophotometric methods to the problem of estimating the concentration of hemoglobin in blood. The concentration of a substance in solution can easily be determined from its transmission of some particular wave length, providing the absorption ratio for that wave length is known. A late model direct reading spectrophotometer was used. The method was found to be fairly accurate and simple and should prove valuable in other physical investigations involving the study of spectral transmission curves of various colored substances. Some interesting irregularities in the shape of the spectral transmission curve in one of the absorption bands of oxyhemoglobin were observed. These investigations were carried out under the direction of Professor Charles Sheard in the Section of Physics at the Mayo Clinic, Rochester, Minnesota