Method for retarding dye fading during archival storage of developed color photographic film

Dye fading during archival storage of developed color photographic film is retarded by placing the film in a sealed, opaque vault, introducing a dry, pressurized inert gas into the vault while the latter is vented, and sealing the vault after the air within the vault has been purged and replaced by the inert gas. Preferably, the gas is nitrogen; and the vault is stored at a temperature below room temperature to preserve the color photographic emulsions on the film contained within the vault. For short-term storage, sodium thiocyanate pads charged with water are placed within the vault. For long term storage, the interior of the vault is kept at a low relative humidity

Rebar Impalement Safety

This project is sponsored by Webcor with the purpose of finding a better solution to rebar impalement safety. The current rebar impalement safety caps being used by Webcor were found to frequently fall off after being installed. This results in workers being exposed to the hazard for longer than desired. The research that has been done by the team showed that rebar impalement is a serious hazard and results in injury or death every year. Site visits and interviews were performed to aid in understanding the problem and designing solutions. The customer needs, current state of the problem, existing solutions, historical data relevant to the project and the materials and methods of manufacturing were thoroughly researched and considered when designing potential solutions. The team followed the Define, Measure, Analyze, Improve and control methodology when approaching the project. Once the current state was defined and measured through research and testing of the currently available caps, the team designed and tested a new prototype cap. The tests included vertical pull tests to determine how much force was required to remove a cap, a strike test to determine how well a given cap would withstand a sudden impact to the bar it is installed on, and a durability test to compare how well different materials withstood repeated installation. After comparing the results, it was found that the new prototype outperformed the current safety caps in all tests. The two key factors of the new design that were found to be significant during testing were: the materials it was made of and the design of the interior of the cap where it’s installed onto the bar. Using the results and experiences from the testing phase the team designed a improved version of the prototype, but were unable to produce or test it due to the time constraints of the project. Several considerations were taken when designing the final design: manufacturability, materials, sustainability and durability

Scaling Solutions to 6D Gauged Chiral Supergravity

We construct explicitly time-dependent exact solutions to the field equations of 6D gauged chiral supergravity, compactified to 4D in the presence of up to two 3-branes situated within the extra dimensions. The solutions we find are scaling solutions, and are plausibly attractors which represent the late-time evolution of a broad class of initial conditions. By matching their near-brane boundary conditions to physical brane properties we argue that these solutions (together with the known maximally-symmetric solutions and a new class of non-Lorentz-invariant static solutions, which we also present here) describe the bulk geometry between a pair of 3-branes with non-trivial on-brane equations of state.Comment: Contribution to the New Journal of Physics focus issue on Dark Energy; 28 page

Kicking the Rugby Ball: Perturbations of 6D Gauged Chiral Supergravity

We analyze the axially-symmetric scalar perturbations of 6D chiral gauged supergravity compactified on the general warped geometries in the presence of two source branes. We find all of the conical geometries are marginally stable for normalizable perturbations (in disagreement with some recent calculations) and the nonconical for regular perturbations, even though none of them are supersymmetric (apart from the trivial Salam-Sezgin solution, for which there are no source branes). The marginal direction is the one whose presence is required by the classical scaling property of the field equations, and all other modes have positive squared mass. In the special case of the conical solutions, including (but not restricted to) the unwarped `rugby-ball' solutions, we find closed-form expressions for the mode functions in terms of Legendre and Hypergeometric functions. In so doing we show how to match the asymptotic near-brane form for the solution to the physics of the source branes, and thereby how to physically interpret perturbations which can be singular at the brane positions.Comment: 21 pages + appendices, references adde

HORIZONTAL BAR DISPLACEMENTS OF WOMEN WEIGHTLIFTERS DURING THE SNATCH

The purpose of this study was to analyze the horizontal bar displacement of women weightlifters while performing the snatch. Thirty lifts performed at the 1999 United States National Weightlifting Championships were recorded and analyzed using a Peak5 2D Motion Analysis System. Three key displacement values were obtained for each lift: first pull, second pull, and just after peak height. The magnitude of bar displacement ranged from –3 to 8cm, for the first pull –14 to 14cm, for the second pull, and –3 to 21cm just after peak height is attained. Lifters did not display the horizontal displacement pattern that is described for men in the current literature

KINEMATIC ANALYSIS OF THE BAR DROP DISPLACEMENT IN THE SNATCH

The purpose of this study was to analyze drop-under time, maximum vertical barbell displacement, vertical barbell drop and maximum vertical barbell velocity during the 1999 United States National Weightlifting Championships. The performance of ten female lifters performing 30 lifts was recorded and analyzed using a Peak5 2D Motion Analysis System. These variables were observed for lifters who successfully performed multiple lifts to determine the trends that take place as the load of the barbell increases. Average maximum vertical barbell displacement was 101.5(cm) with a SD of 7.4. Average vertical barbell drop displacement was 20.8(cm) with a SD of 5.9. Average maximum vertical velocity of the barbell was 164.8(cm/s) with a SD of 19.1. Average drop-under time was .47(s) with a SD of .09

Ion dynamics in a linear radio-frequency trap with a single cooling laser

We analyse the possibility of cooling ions with a single laser beam, due to the coupling between the three components of their motion induced by the Coulomb interaction. For this purpose, we numerically study the dynamics of ion clouds of up to 140 particles, trapped in a linear quadrupole potential and cooled with a laser beam propagating in the radial plane. We use Molecular Dynamics simulations and model the laser cooling by a stochastic process. For each component of the motion, we systematically study the dependence of the temperature with the anisotropy of the trapping potential. Results obtained using the full radio-frequency (rf) potential are compared to those of the corresponding pseudo-potential. In the rf case, the rotation symmetry of the potential has to be broken to keep ions inside the trap. Then, as for the pseudo-potential case, we show that the efficiency of the Coulomb coupling to thermalize the components of motion depends on the geometrical configuration of the cloud. Coulomb coupling appears to be not efficient when the ions organise as a line or a pancake and the three components of motion reach the same temperature only if the cloud extends in three dimensions

Comment on the calculation of forces for multibody interatomic potentials

The system of particles interacting via multibody interatomic potential of general form is considered. Possible variants of partition of the total force acting on a single particle into pair contributions are discussed. Two definitions for the force acting between a pair of particles are compared. The forces coincide only if the particles interact via pair or embedded-atom potentials. However in literature both definitions are used in order to determine Cauchy stress tensor. A simplest example of the linear pure shear of perfect square lattice is analyzed. It is shown that, Hardy's definition for the stress tensor gives different results depending on the radius of localization function. The differences strongly depend on the way of the force definition.Comment: 9 pages, 2 figure

Configurational temperature control for atomic and molecular systems

A new configurational temperature thermostat suitable for molecules with holonomic constraints is derived. This thermostat has a simple set of motion equations, can generate the canonical ensemble in both position and momentum space, acts homogeneously through the spatial coordinates, and does not intrinsically violate the constraints. Our new configurational thermostat is closely related to the kinetic temperature Nosé-Hoover thermostat with feedback coupled to the position variables via a term proportional to the net molecular force. We validate the thermostat by comparing equilibrium static and dynamic quantities for a fluid of n-decane molecules under configurational and kinetic temperature control. Practical aspects concerning the implementation of the new thermostat in a molecular dynamics code and the potential applications are discussed