The hose u-tube level

With the growing use of soil conservation practices throughout the farming areas, there has been an increasing demand for a simple levelling device that will enable farmers to take their own levels. When they have become familiar with the use of pasture furrows, contour banks and the various other mechanical erosion control measures, farmers with the aid of such an instrument would be able to make an immediate start on an erosion control programme. The instrument would also prove useful for numerous small jobs around the farm when accurate levels are required. Tests have shown the Hose U-Tube Level here described, to be an accurate and reliable farm levelling instrument

Point Source C-Band Mueller Matrices for the Green Bank Telescope

C-Band Mueller matrices for the Green Bank Telescope are presented here which enable on-sky Stokes parameters for point sources at the beam center to be determined. Standard calibrators, 3C138 and 3C286, were observed using the Spider program to steer the telescope across a broad range of Right Ascensions on both sides of the zenith transit. For this analysis, only the observations at the peak of the Spider pattern were used rather than the full sweep of the runs. Therefore, the results presented here only apply to point sources at the beam center. The Mueller matrices are shown to vary with frequency and with use of the Hi-Cal or Lo-Cal noise diodes, due to the relative calibration gain between the X and Y components of the feed. However, the relative calibration gain can be determined from observations of a source with known polarization. Correcting the data for the relative calibration gain prior to data analysis allows for use of a frequency independent Mueller matrix. This generic Mueller matrix is shown to provide reliable C-Band polarization measurements.Comment: Acceptance for publication in The Astronomical Journa

Superdeformation in 198^{198}Po

The $^{174}$Yb($^{29}$Si,5n) reaction at 148 MeV with thin targets was used to populate high-angular momentum states in $^{198}$Po. Resulting $\gamma$ rays were observed with Gammasphere. A weakly-populated superdeformed band of 10 $\gamma$-ray transitions was found and has been assigned to $^{198}$Po. This is the first observation of a SD band in the $A \approx 190$ region in a nucleus with $Z > 83$. The ${\cal J}^{(2)}$ of the new band is very similar to those of the yrast SD bands in $^{194}$Hg and $^{196}$Pb. The intensity profile suggests that this band is populated through states close to where the SD band crosses the yrast line and the angular momentum at which the fission process dominates.Comment: 10 pages, revtex, 2 figs. available on request, submitted to Phys. Rev. C. (Rapid Communications

A stacking-fault based microscopic model for platelets in diamond

We propose a new microscopic model for the $\{001\}$ planar defects in diamond commonly called platelets. This model is based on the formation of a metastable stacking fault, which can occur because of the ability of carbon to stabilize in different bonding configurations. In our model the core of the planar defect is basically a double layer of three-fold coordinated $sp^2$ carbon atoms embedded in the common $sp^3$ diamond structure. The properties of the model were determined using {\it ab initio} total energy calculations. All significant experimental signatures attributed to the platelets, namely, the lattice displacement along the $[001]$ direction, the asymmetry between the $[110]$ and the $[1\bar{1}0]$ directions, the infrared absorption peak $B^\prime$, and broad luminescence lines that indicate the introduction of levels in the band gap, are naturally accounted for in our model. The model is also very appealing from the point of view of kinetics, since naturally occurring shearing processes will lead to the formation of the metastable fault.Comment: 5 pages, 4 figures. Submitted for publication on August 2nd, 200

On the equivalence of pairing correlations and intrinsic vortical currents in rotating nuclei

The present paper establishes a link between pairing correlations in rotating nuclei and collective vortical modes in the intrinsic frame. We show that the latter can be embodied by a simple S-type coupling a la Chandrasekhar between rotational and intrinsic vortical collective modes. This results from a comparison between the solutions of microscopic calculations within the HFB and the HF Routhian formalisms. The HF Routhian solutions are constrained to have the same Kelvin circulation expectation value as the HFB ones. It is shown in several mass regions, pairing regimes, and for various spin values that this procedure yields moments of inertia, angular velocities, and current distributions which are very similar within both formalisms. We finally present perspectives for further studies.Comment: 8 pages, 4 figures, submitted to Phys. Rev.