Penetration experiments with fiberglass-reinforced plastics

The penetration resistance of fiberglass-reinforced plastics against small-caliber projectiles is determined by firing experiments. Relations, found to be linear, between energy loss, stopping power and thickness of plate are given. The effect of distance of separation, for two plates, on stopping power is determined. The weight efficiency of the fiberglass cloth is found to be greater than steel.     

The doppler shift lifetimes facility

The Doppler Shift Lifetimes chamber is an experimental facility designed to measure the mean lifetimes of excited nuclear states that decay within femtoseconds via the detection of their Doppler-shifted γ ray transitions.     

Solutions to the Modified Pöschl-Teller Potential in D-Dimensions

An approximate solution of the D-dimensional Schrödinger equation with the modified Pöschl-Teller potential is obtained with an approximation of the centrifugal term. Solution to the corresponding hyper-radial equation is given using the conventional Nikiforov-Uvarov method. The normalization constants for the Pöschl-Teller potential are also computed. The expectation values of -2_> and are also obtained using the Feynman-Hellmann theorem.     

Ground state proton radioactivity from 121Pr: when was this exotic nuclear decay mode first discovered?

Ground-state proton radioactivity has been identified from 121Pr. A transition with a proton energy of E(p)=882(10) keV [Q(p)=900(10) keV] and half-life t(1/2)=10(+6)(-3) ms has been observed and is assigned to the decay of a highly prolate deformed 3/2(+) or 3/2(-) Nilsson state. The present result is found to be incompatible with a previously reported observation of ground-state proton radioactivity from 121Pr, which would have represented the discovery of this phenomenon.     

Structure of the odd-A, shell-stabilized nucleus 253/102No

In-beam gamma-ray spectroscopic measurements have been made on 253/102No. A single rotational band was identified up to a probable spin of 39/2planck, which is assigned to the 7/2(+)[624] Nilsson configuration. The bandhead energy and the moment of inertia provide discriminating tests of contemporary models of the heaviest nuclei. Novel methods were required to interpret the sparse data set associated with cross sections of around 50 nb. These methods included comparisons of experimental and simulated spectra, as well as testing for evidence of a rotational band in the gammagamma matrix.     

S17(0) determined from the Coulomb breakup of 83 MeV /nucleon 8B

A kinematically complete measurement was made of the Coulomb dissociation of 8B nuclei on a Pb target at 83 MeV/nucleon. The cross section was measured at low relative energies in order to infer the astrophysical S factor for the 7Be(p,gamma)8B reaction. A first-order perturbation theory analysis including E1, E2, and M1 transitions was employed to extract the E1 strength relevant to neutrino-producing reactions in the solar interior. By fitting the measured cross section from E(rel) = 130 to 400 keV, we find S17(0) = 17.8(+1.4)(-1.2) eV b.     

Comparative electrooxidation of nitrite by electrodeposited Co(II), Fe(II) and Mn(III) tetrakis (benzylmercapto) and tetrakis (dodecylmercapto) phthalocyanines on gold electrodes

This work reports on the electrooxidation of nitrite using Co(II), Fe(II) and Mn(III) tetrakis (benzylmercapto) and tetrakis (dodecylmercapto) phthalocyanines electrodeposited onto a gold electrode. Good catalytic activity (in terms of lowering overpotential) was obtained for these molecules when compared to previously reported MPc catalysts. The catalytic current was found to vary linearly with nitrite concentration in the range employed in this work (0.1-1 mM) and high sensitivities ranging from 6.9 to 9.9 μA mM⁻¹ were observed for all the modified electrodes.     

The moiré method for the study of explosions

Explosives have been used to produce weak shock waves in central cavities of Plexiglas spheres. Shock pressures engendered were less than the so-called stable shock threshold and they resulted in a decomposition of the shock wave into an elastic precursor preceding the so-called plastic shock wave. The differential moiré method has been used to measure simultaneously the precursor and shock-wave velocities, as well as the velocity of the cavity interface. Moreover, the displacement field given by the moiré pattern yields the components of strains and the particle velocity behind each shock.     

Coupled experiments and simulations of microstructural damage in wood

In this paper, we explore ways to couple experimental measurements with the numerical simulations of the mechanical properties of wood. For our numerical simulations, we have adopted a lattice approach, where wood fibers or bundles of wood fibers are modeled as discrete structural elements connected by a lattice of spring elements. Element strength and stiffness properties are determined from bulk material properties. Damage is represented by broken lattice elements, which cause both stiffness and strength degradation. The modeling approach was applied to small specimens of spruce subjected to transverse uniaxial tension, and mode I transverse splitting. The model was found to be good at predicting the load-deformation response of both notched and unnotched specimens, including the post-peak softening response. In addition, the damage patterns predicted by the model are consistent with those observed in the experiments.     

Grothendieck Groups of Bundles on Varieties over Finite Fields

Let X be an irreducible, projective variety over a finite field, and let A be a sheaf of rings on X. In this paper, we study Grothendieck groups of categories of vector bundles over certain types of ringed spaces (X,A).