DOE Backup Power Working Group Best Practices Handbook for Maintenance and Operation of Engine Generators, Volume II

The lubricating oil system provides a means to introduce a lubricant in the form of a film to reduce friction and wear between surfaces that bear against each other as they move.1 The oil film which is established also cools the parts by carrying generated heat away from hot surfaces, cleans and carries dirt or metal wear particles to the filter media, and helps seal the piston to the cylinder during combustion. Most systems are pressure lubricated and distribute oil under pressure to bearings, gears, and power assemblies. Lubricating oil usually reaches main, connecting rod, and camshaft bearings through drilled passages in the cylinder block and crankshaft or through piping and common manifolds.Many parts rely on oil for cooling, so if the lube oil system fails to perform its function the engine will overheat. Metal to metal surfaces not separated by a thin film of oil rapidly build up frictional heat. As the metals reach their melting point, they tend to weld together in spots or streaks. Lube oil system failures can cause significant damage to an engine in a short period of time. Proper maintenance and operation of the lubricating oil system is essential if your engine is to accomplish its mission

Alternative Signature of TeV Strings

In string theory, it is well known that any hard scattering amplitude inevitably suffers exponential suppression. We demonstrate that, if the string scale is M_s < 2TeV, this intrinsically stringy behavior leads to a dramatic reduction in the QCD jet production rate with very high transverse momenta p_T > 2TeV at LHC. This suppression is sufficient to be observed in the first year of low-luminosity running. Our prediction is based on the universal behavior of string theory, and therefore is qualitatively model-independent. This signature is alternative and complementary to conventional ones such as Regge resonance (or string ball/black hole) production.Comment: a note added; version to appear in Phys. Rev. D; 11 pages, 1 eps figure, LaTeX2e; BibTeX with utphys style use

A determination of <A^2> and the non-perturbative vacuum energy of Yang-Mills theory in the Landau gauge

We discuss the 2-point-particle-irreducible (2PPI) expansion, which sums bubble graphs to all orders, in the context of SU(N) Yang-Mills theory in the Landau gauge. Using the method we investigate the possible existence of a gluon condensate of mass dimension two, , and the corresponding non-zero vacuum energy. This condensate gives rise to a dynamically generated mass for the gluon.Comment: 12 pages, 3 eps figures; v2 : wrong use of "enhancement" instead of "suppression" corrected; v3: version accepted for publication in Phys.Lett.

Biopolymer additives for the reduction of soil erosion losses during irrigation

High molecular weight, synthetic polyacrylamides (PAM) are relatively large, water soluble polymers that are used increasingly by farmers to prevent erosion and increase infiltration during irrigation. A lab-scale erosion test was conducted to screen biopolymer solutions for a similar efficacy in reducing shear-induced erosion. In lab-scale mini-furrow tests, chitosan, starch xanthate, cellulose xanthate, and acid-hydrolyzed cellulose microfibrils, at concentrations of 20, 80, 80, and 120 ppm respectively, reduced suspended solids in the runoff water from test soil. None of these biopolymers, however, exhibited the >90% runoff sediment reduction shown by PAM at concentrations as low as 5 ppm. Preliminary field tests results showed that chitosan solutions were only marginally effective in reducing runoff from a 137m long furrow. There were indications that results were dependent on the length of the furrow. Erosion of some clay-rich soils from Northern California was reduced up to 85% by increasing the concentration of exchangeable calcium to >2.5mMole, with or without the addition of polymer additives

Fluid-based radon mitigation technology development for industrial applications

The objective of the radon mitigation technology development effort is to develop an efficient and economical radon gas removal technology based on a fluid absorption process. The technology must be capable of cleaning up a wide range of radon gas stream concentrations to a level that meets EPA gas emission standards for residential and industrial applications. Argonne has recently identified a phenomenon that offers the possibility of radon recovery from the atmosphere with high efficiency at room temperature, and radon release at slightly elevated temperatures (50-60 degrees C.) such a device would offer numerous substantial advantages over conventional cryogenic charcoal systems for the removal of radon. Controlled sources of radon in Argonne`s radon research facility are being used to quantitatively assess the performance of a selected class of absorbing fluids over a range of radon concentrations. This paper will discuss the design of laboratory- and engineering-scale radon absorption units and present some preliminary experimental test results

Semiclassical Solution of the Quantum Hydrodynamic Equation for Trapped Bose-condensed Gas in the l=0 Case

In this paper the quantum hydrodynamic equation describing the collective, low energy excitations of a dilute atomic Bose gas in a given trapping potential is investigated with the JWKB semiclassical method. In the case of spherically symmetric harmonic confining potential a good agreement is shown between the semiclassical and the exact energy eigenvalues as well as wave functions. It is also demonstrated that for larger quantum numbers the calculation of the semiclassical wave function is numerically more stable than the exact polynomial with large alternating coefficients.Comment: 12 pages, 7 figure

Self Consistent 1/Nc1/N_c Expansion In The Presence Of Electroweak Interactions

In the conventional approach to the $1/N_c$ expansion, electroweak interactions are switched off and large $N_c$ QCD is treated in isolation. We study the self-consistency of taking the large $N_c$ limit in the presence of electroweak interaction. If the electroweak coupling constants are held constant, the large $N_c$ counting rules are violated by processes involving internal photon or weak boson lines. Anomaly cancellations, however, fix the ratio of electric charges of different fermions. This allows a self-consistent way to scale down the electronic charge $e$ in the large $N_c$ limit and hence restoring the validity of the large $N_c$ counting rules.Comment: 9 pages in REVTeX, no figure

Macroscopic Quantum Fluctuations in the Josephson Dynamics of Two Weakly Linked Bose-Einstein Condensates

We study the quantum corrections to the Gross-Pitaevskii equation for two weakly linked Bose-Einstein condensates. The goals are: 1) to investigate dynamical regimes at the borderline between the classical and quantum behaviour of the bosonic field; 2) to search for new macroscopic quantum coherence phenomena not observable with other superfluid/superconducting systems. Quantum fluctuations renormalize the classical Josephson oscillation frequencies. Large amplitude phase oscillations are modulated, exhibiting collapses and revivals. We describe a new inter-well oscillation mode, with a vanishing (ensemble averaged) mean value of the observables, but with oscillating mean square fluctuations. Increasing the number of condensate atoms, we recover the classical Gross-Pitaevskii (Josephson) dynamics, without invoking the symmetry-breaking of the Gauge invariance.Comment: Submitte

Formation and control of electron molecules in artificial atoms: Impurity and magnetic-field effects

Interelectron interactions and correlations in quantum dots can lead to spontaneous symmetry breaking of the self-consistent mean field resulting in formation of Wigner molecules. With the use of spin-and-space unrestricted Hartree-Fock (sS-UHF) calculations, such symmetry breaking is discussed for field-free conditions, as well as under the influence of an external magnetic field. Using as paradigms impurity-doped (as well as the limiting case of clean) two-electron quantum dots (which are analogs to helium-like atoms), it is shown that the interplay between the interelectron repulsion and the electronic zero-point kinetic energy leads, for a broad range of impurity parameters, to formation of a singlet ground-state electron molecule, reminiscent of the molecular picture of doubly-excited helium. Comparative analysis of the conditional probability distributions for the sS-UHF and the exact solutions for the ground state of two interacting electrons in a clean parabolic quantum dot reveals that both of them describe formation of an electron molecule with similar characteristics. The self-consistent field associated with the triplet excited state of the two-electron quantum dot (clean as well as impurity-doped) exhibits symmetry breaking of the Jahn-Teller type, similar to that underlying formation of nonspherical open-shell nuclei and metal clusters. Furthermore, impurity and/or magnetic-field effects can be used to achieve controlled manipulation of the formation and pinning of the discrete orientations of the Wigner molecules. Impurity effects are futher illustrated for the case of a quantum dot with more than two electrons.Comment: Latex/Revtex, 10 pages with 4 gif figures. Small changes to explain the difference between Wigner and Jahn-Teller electron molecules. A complete version of the paper with high quality figures inside the text is available at http://shale.physics.gatech.edu/~costas/qdhelium.html For related papers, see http://www.prism.gatech.edu/~ph274c

Online Interactive Teaching Modules Enhance Quantitative Proficiency of Introductory Biology Students

There is widespread agreement within the scientific and education communities that undergraduate biology curricula fall short in providing students with the quantitative and interdisciplinary problem-solving skills they need to obtain a deep understanding of biological phenomena and be prepared fully to contribute to future scientific inquiry. MathBench Biology Modules were designed to address these needs through a series of interactive, Web-based modules that can be used to supplement existing course content across the biological sciences curriculum. The effect of the modules was assessed in an introductory biology course at the University of Maryland. Over the course of the semester, students showed significant increases in quantitative skills that were independent of previous math course work. Students also showed increased comfort with solving quantitative problems, whether or not they ultimately arrived at the correct answer. A survey of spring 2009 graduates indicated that those who had experienced MathBench in their course work had a greater appreciation for the role of mathematics in modern biology than those who had not used MathBench. MathBench modules allow students from diverse educational backgrounds to hone their quantitative skills, preparing them for more complex mathematical approaches in upper-division courses