## On the Growth Rate of Spherulites and Axialites from the Melt in Polyethylene Fractions: Regime I and Regime II Crystall...

Published in Journal of Research of the National Bureau of Standards. Section A, Physics and Chemistry

Published in Journal of Research of the National Bureau of Standards. Section A, Physics and Chemistry

Published in Journal of Research of the National Bureau of Standards. Section A, Physics and Chemistry

Heat capacities of two polyethylene samples, one linear with a density of 0.973 g cm−3 and one branched with a density of 0.91 g cm−3, have been determined by adiabatic calorimetry from 5 to 360 K in a different experimental arrangement then employed for studies of other polyethylene samples in this series. The heat capacity behavior of these two s...

The droplet technique was used to obtain estimates of the isothermal rate of homogeneous crystal nucleation in highly supercooled melts of 8 characterized fractions of linear polyethylene (weight average molecular weights from 3,100 to 249,000). The data obtained from these experiments were analyzed in accord with current theories of homogeneous nu...

Relativistic line strengths have been computed for a large number of transitions using Dirac wave functions for the one-electron, hydrogen-like ions. As expected, the results indicate that relativistic effects are quite small for low stages of ionization. However, in general, they also remain small throughout a large portion of the isoelectronic se...

Solid sample, thermal ionization, mass spectrometry has been used to obtain absolute values for the isotopic abundance ratios of a reference sample of potassium. Standards of known isotopic composition, prepared by gravimetrically mixing nearly isotopically and chemically pure separated isotopes of, 39K and 41K, were used for calibration. The absol...

The enthalpies of combustion and formation of 2,2′-dichlorethyl sulfìde (mustard gas) have been determined by combustion in an adiabatic rotating-bomb calorimeter. The bomb process has been corrected to: C 4 H 8 Cl 2 S ( liq ) + 7 O 2 ( g ) + 98 H 2 O ( liq ) → 4 CO 2 ( g ) + [ 2 HCl + H 2 SO 4 + 100 H 2 O ] ( liq ) for which the following values w...

The coefficients in van der Poel’s equation for calculating the shear modulus of a particulate composite have been greatly simplified, making the calculation much less unwieldy. Approximate solutions of van der Poel’s equation are also derived, and it is shown that one of the low order approximations is Kernels equation, or Mashin and Shtrikman’s e...

Absolute values have been obtained for the isotopic abundance ratios of a reference sample of silicon using electron impact mass spectrometry. Samples of known isotopic composition prepared from nearly isotopically pure separated silicon isotopes were used to calibrate the mass spectrometers. The resulting absolute 28Si/30Si ratio=29.74320±0.00747 ...

Polarization effects on fluorescence measurements are a function of four independent variables. The first is F , the polarization ratio of the exciting light which reaches the sample. The second is r , the emission anisotropy of the sample, which is the polarization “response” of the sample to plane polarized exciting light. The third is G , the po...

It is standard procedure to fit an applicable isotherm equation to water vapor adsorption data using the method of least squares in arriving at a value for the surface area accessible to the water molecule. The least squares technique has been extended in the present investigation to determine, in addition and simultaneously, a “best value” for the...