Superconducting six-axis accelerometer

A new superconducting accelerometer, capable of measuring both linear and angular accelerations, is under development at the University of Maryland. A single superconducting proof mass is magnetically levitated against gravity or any other proof force. Its relative positions and orientations with respect to the platform are monitored by six superconducting inductance bridges sharing a single amplifier, called the Superconducting Quantum Interference Device (SQUID). The six degrees of freedom, the three linear acceleration components and the three angular acceleration components, of the platform are measured simultaneously. In order to improve the linearity and the dynamic range of the instrument, the demodulated outputs of the SQUID are fed back to appropriate levitation coils so that the proof mass remains at the null position for all six inductance bridges. The expected intrinsic noise of the instrument is 4 x 10(exp -12)m s(exp -2) Hz(exp -1/2) for linear acceleration and 3 x 10(exp -11) rad s(exp -2) Hz(exp -1/2) for angular acceleration in 1-g environment. In 0-g, the linear acceleration sensitivity of the superconducting accelerometer could be improved by two orders of magnitude. The design and the operating principle of a laboratory prototype of the new instrument is discussed

Development of a sensitive superconducting gravity gradiometer for geological and navigational applications

A sensitive and stable gravity gradiometer would provide high resolution gravity measurements from space. The instrument could also provide precision tests of fundamental laws of physics and be applied to inertial guidance systems of the future. This report describes research on the superconducting gravity gradiometer program at the University of Maryland from July 1980 to July 1985. The report describes the theoretical and experimental work on a prototype superconducting gravity gradiometer. The design of an advanced three-axis superconducting gravity gradiometer is also discussed

Solidification of undercooled liquids

During rapid solidification processing (RSP) the amount of liquid undercooling is an important factor in determining microstructural development by controlling phase selection during nucleation and morphological evolution during crystal growth. While undercooling is an inherent feature of many techniques of RSP, the deepest undercoolings and most controlled studies have been possible in carefully prepared fine droplet samples. From past work and recent advances in studies of nucleation kinetics it has become clear that the initiation of crystallization during RSP is governed usually by heterogeneous sites located at surfaces. With known nucleant sites, it has been possible to identify specific pathways of metastable phase formation and microstructural development in alloys. These advances have allowed for a clearer assessment of the interplay between undercooling, cooling rate and particle size statistics in structure formation. New approaches to the examination of growth processes have been developed to follow the thermal behavior and morphology in small samples in the period of rapid crystallization and recalescence. Based upon the new experimental information from these studies, useful models can be developed for the overall solidification process to include nucleation behavior, thermodynamic constraints, thermal history, growth kinetics, solute redistribution and resulting structures. From the refinement of knowledge concerning the underlying factors that govern RSP a basis is emerging for an effective alloy design and processing strategy

Ultrafast vectorial and scalar dynamics of ionic clusters: Azobenzene solvated by oxygen

The ultrafast dynamics of clusters of trans-azobenzene anion (A–) solvated by oxygen molecules was investigated using femtosecond time-resolved photoelectron spectroscopy. The time scale for stripping off all oxygen molecules from A– was determined by monitoring in real time the transient of the A– rise, following an 800 nm excitation of A– (O2)n, where n=1–4. A careful analysis of the time-dependent photoelectron spectra strongly suggests that for n>1 a quasi-O4 core is formed and that the dissociation occurs by a bond cleavage between A– and conglomerated (O2)n rather than a stepwise evaporation of O2. With time and energy resolutions, we were able to capture the photoelectron signatures of transient species which instantaneously rise (2- for A–O2 and A·O4-·(O2)n–2 for A–(O2)n, where n=2–4. Subsequent to an ultrafast electron recombination, A– rises with two distinct time scales: a subpicosecond component reflecting a direct bond rupture of the A–-(O2)n nuclear coordinate and a slower component (1.6–36 ps, increasing with n) attributed to an indirect channel exhibiting a quasistatistical behavior. The photodetachment transients exhibit a change in the transition dipole direction as a function of time delay. Rotational dephasing occurs on a time scale of 2–3 ps, with a change in the sign of the transient anisotropy between A–O2 and the larger clusters. This behavior is a key indicator of an evolving cluster structure and is successfully modeled by calculations based on the structures and inertial motion of the parent clusters

Quartz crystal microbalance use in biological studies

Design, development, and applications of quartz crystal microbalance are discussed. Two types of crystals are used. One serves as reference and other senses changes in mass. Specific application to study of bacterial spores is described

Numerical investigation of non-linear deflections of an infinite beam on non-linear and discontinuous elastic foundation

The analysis of static deflections of an infinite beam resting on a non-linear and discontinuous foundation is not trivial. We apply a recently proposed iterative non-linear procedure to the analysis. Mathematical models of the elastic foundation are incorporated into the governing non-linear fourth-order differential equation of the system and then the differential equation is transformed into an equivalent non-linear integral equation using Green's functions. Numerical solutions of the integral equation clearly demonstrate herein that our non-linear iterative numerical method is simple and straightforward for approximate solutions of the static deflection of an infinite beam on a non-linear elastic foundation. Iterative numerical solutions converge fast to corresponding analytic solutions. However, numerical errors are observed in a narrow neighbourhood of material discontinuities of foundations

Expression of hMLH1 is inactivated in the gastric adenomas with enhanced microsatellite instability

Microsatellite instability (MSI) and frameshift mutations in the genes containing coding nucleotide repeats have been reported in a subset of gastric adenomas, however the inactivation profiles of DNA mismatch repair genes in MSI-positive gastric adenomas have not been characterized. To address the origin of MSI in gastric adenomas, expressions of hMLH1 and hMSH2 were explored in 86 gastric adenomas. Gastric carcinomas, of which 16 were MSI-positive and 22 MSI-negative, were used as controls. MSI was found in 15 (17%) of gastric adenomas. Absent or decreased hMLH1 expression by immunohistochemistry was noted in most of the MSI-positive adenomas (13/15, 87%) and carcinomas (14/16, 88%), and all of these tumours showed methylation of the hMLH1 gene promoter. In contrast, rare inactivation of hMLH1 expression was found in MSI-negative adenomas (3/71, 4%) and carcinomas (2/22, 9%). Intense expression of hMSH2 gene product was observed in most of the gastric adenomas and carcinomas regardless of MSI status. These findings indicate that the inactivation of hMLH1 gene expression by promoter methylation is an early event and might be the origin of MSI-positive gastric adenomas. © 2001 Cancer Research Campaign  http://www.bjcancer.co

On The 5D Extra-Force according to Basini-Capozziello-Leon Formalism and five important features: Kar-Sinha Gravitational Bending of Light, Chung-Freese Superluminal Behaviour, Maartens-Clarkson Black Strings, Experimental measures of Extra Dimensions on board International Space Station(ISS) and the existence of the Particle ZZ due to a Higher Dimensional spacetime

We use the Conformal Metric as described in Kar-Sinha work on Gravitational Bending of Light in a 5D Spacetime to recompute the equations of the 5D Force in Basini-Capozziello-Leon Formalism and we arrive at a result that possesses some advantages. The equations of the Extra Force as proposed by Leon are now more elegant in Conformal Formalism and many algebraic terms can be simplified or even suppressed. Also we recompute the Kar-Sinha Gravitational Bending of Light affected by the presence of the Extra Dimension and analyze the Superluminal Chung-Freese Features of this Formalism describing the advantages of the Chung-Freese BraneWorld when compared to other Superluminal spacetime metrics(eg:Warp Drive) and we describe why the Extra Dimension is invisible and how the Extra Dimension could be made visible at least in theory.We also examine the Maartens-Clarkson Black Holes in 5D(Black Strings) coupled to massive Kaluza-Klein graviton modes predicted by Extra Dimensions theories and we study experimental detection of Extra Dimensions on-board LIGO and LISA Space Telescopes.We also propose the use of International Space Station(ISS) to measure the additional terms(resulting from the presence of Extra Dimensions) in the Kar-Sinha Gravitational Bending of Light in Outer Space to verify if we really lives in a Higher Dimensional Spacetime.Also we demonstrate that Particle $Z$ can only exists if the 5D spacetime exists.Comment: Withdrawn: author no longer wishes to post work on arXi