Optical Instrument Survival In A Major Earthquake

Many organizations presently are evaluating the potential loss to plant, equipment and production capability in event of a major earthquake in their area. Often it is found that equipment can be protected at a fraction of the replacement cost. The paper discusses ground accelerations, seismic probability and certain characteristics of earthquake ground motion. Methods for determining loads from the Uniform Building Code and acceleration response spectrums are explained. Protection techniques for optical equipment are presented including rigid anchors, snubbers and sensing systems. The paper is for optical engineers and managers, with no particular background in seismology or structural engineering required

Li-8 Magnetic Dipole-Moment

Polarized 8Li nuclei recoiling from the reaction 7Li(d, p)8Li were implanted in Au, Pd, and Pt foils, and the Knight-shifted values of the 8Li magnetic dipole moment in these metals were measured by a resonant depolarization technique. From measurements of the spinlattice relaxation times of 8Li implanted in Au, Pd, and Pt, the Knight shifts of 8Li in these metals were estimated. A corrected value for the magnetic dipole moment of 8Li was found to be μ(8Li)=(1.653 35±0.000 35)μN. Attempts were also made to measure the quadrupole couplings of 8Li in single crystals of Be and Mg. While the resonance lines could not be distinctly resolved, upper and lower limits have been deduced for |e2qQ/h| in these two metals

Problems of Channel Correlation and Statistical Bias in Photon-Correlation Spectroscopy

Correlation between channels of the normalized photocount-rate correlation function g(2)(τ) becomes significant at high count rates and leads to a number of data-analysis problems. We derive an expression for channel correlation that is valid for a detector area of arbitrary extent and compare the theoretical predictions with measured values. A data-analysis procedure is demonstrated that employs the theoretical expression for channel correlation and provides a rigorous test of an assumed fitting function. The procedure facilitates the use of the cumulant method in determining the polydispersity of scatterers. An expression for the statistical bias of g(2)(τ) is also derived and compared with measured values

Buckling of channel flanges during bending in the weak direction

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Civil and Sanitary Engineering, 1960.Includes bibliographical references (leaves 69-70).by Richard C. Haskell.M.S

Light-Scattering Technique for the Study of Dynamic Thickness Fluctuations in Thin Liquid Films

The authors describe a light-scattering technique capable of probing the dynamics of thickness fluctuations in lipid bilayers. The technique, which they call reflectance fluctuation spectroscopy (RFS), is keenly sensitive to light scattered from the squeeze modes of motion in a thin liquid film, and insensitive to light scattered from the bend modes. A laser beam is focused to a small spot on the film, and the power in the specularly reflected beam is recorded in real time. Thickness fluctuations associated with the squeeze modes of motion give rise to fluctuations in the power of the specularly reflected light. The frequency spectrum of the fluctuations in detected power (RFS spectrum) can be analyzed to yield values for the film viscosity and thickness compressibility. The authors present two independent theoretical derivations of the RFS spectrum and show that scattering from the bend mode can be neglected. The theoretical expression for the RFS spectrum is compared with experimental spectra obtained from glycerylmonooleate-decane bilayers. The fit of the theory to the data is excellent and the values deduced for the film viscosity and thickness compressibility are reasonable

Quadrupole Couplings of N12 and B12 Implanted in Metal Single-Crystals

Measurements have been made of the quadrupole couplings of 12N implanted in single crystals of Be and Mg and of 12B implanted in a single crystal of Zn. A comparison of the 12N couplings in Be and Mg suggests that (i) the final stopping sites of the implanted 12N ions are substitutional sites, i.e., the 12N ions occupy metal-ion lattice positions, and (ii) the 12N ions implanted in Be and Mg have the same charge state and quadrupole shielding factor. A procedure is outlined for deducing Q(12N). The 12B couplings in Zn imply the existence of two inequivalent stopping sites. The problems encountered in deducing Q(12B) from couplings in metal hexagonal crystals are discussed

Study of Stopping Sites of B12 Nuclei Implanted in Hexagonal Single-Crystals

A series of experiments to study the stopping sites of 12B nuclei implanted in single crystals of Be and Mg will be discussed. Previous measurements of the quadrupole couplings of 12B in these metals indicated that two different stopping sites existed, one of which produced a negligible quadrupole coupling

Immunogold Labeling to Enhance Contrast in Optical Coherence Microscopy of Tissue Engineered Corneal Constructs

Our lab has used an optical coherence microscope (OCM) to assess both the structure of tissue-engineered corneal constructs and their transparency. Currently, we are not able to resolve cells versus collagen matrix material in the images produced. We would like to distinguish cells in order to determine if they are viable while growing in culture and also if they are significantly contributing to the light scattering in the tissue. In order to do this, we are currently investigating the use of immunogold labeling. Gold nanoparticles are high scatterers and can create contrast in images. We have conjugated gold nanoparticles to antibodies specific to the α5 β1 integrins expressed in some corneal cells. This choice of target should allow assessment of the phenotypic behavior of the cells in the tissue, as different integrins are expressed in different phenotypes. This study applies the immunogold technique to study cultured corneal cells using the OCM with the ultimate goal of monitoring cellular behavior in engineered tissue and corroborating results from standard histological methods

Measurement of Nuclear Magnetic Dipole Moment of Li-8 by Implantation in Metal Foils

Polarized 8Li nuclei have been produced through the 7Li(d,p) reaction using the 3.5-MeV Van de Graaff accelerator at Brookhaven National Laboratory. The observed polarization was a slowly-varying function of deuteron energy over the range 1.3-2.9 MeV, reaching a maximum of about +1.6%. The recoiling nuclei were stopped in Au, Pt and Pd foils and the effective dipole moments were measured by a resonant depolarization method. The results were 1.65362(22)µN, 1.65288(20)µN and 1.65270(30)µN respectively. These are consistent with the work of Connor, who found µ(8Li) =1.6530(8)µN in a LiF crystal. An upper limit for the 8Li quadrupole moment will also be discussed

Observation of Quadrupole Splitting of B-12 in a Single Crystal

The quadrupole coupling of B-12 implanted in Be-9 has been observed using a single crystal of Be. One sees a narrow resonance line, the location of which depends in the normal way on the orientation of the crystalline c-axis with respect to the external magnetic field direction. The coupling constant is given by e2qQ/h = 54.9(6) kHz. This is consistent with our previous measurement using a Be foil. Using the field gradient at Be-9 lattice sites, calculated by Pomerantz and Das, one finds Q(B-12) = about 34.6 mb