Nickel/tin coating protects threaded fasteners in corrosive environment

Threaded fasteners used in corrosive environments are plated with electroless nickel and electroplated, over the nickel, with tin. This provides a corrosion-resistant coating for the fasteners

Rediscovery and redescription of Ceradryops punctatus Hinton, 1937 (Coleoptera: Dryopidae)

Ceradryops punctatus Hinton from Sri Lanka is redescribed and illustrated. Notes are made on the habitat of the species

Three new species of Hexanchorus Sharp, 1882 (Coleoptera: Elmidae: Larainae) from South America

Three new species of Hexanchorus Sharp, H. dimorphus and H. shannoni from Argentina, and H. mcdiarmidi from Venezuela, are described and illustrated

Luchoelmis : a new genus of Elmidae (Coleoptera) from Chile and Argentina

Luchoelmis New Genus is described with four new species: aequalis, magallanensis, and penai from Chile and cekalovici from Argentina and Chile. Luchoelmis penai is designated as the type species of the genus. A key to the four species is presented

On Measurement of Helicity Parameters in Top Quark Decay

To enable an evaluation of future measurements of the helicity parameters for " t --> W b " decay in regard to " T_FS violation", this paper considers the effects of an additional pure-imaginary coupling, (i g/2 Lambda) or (i g), associated with a specific, single additional Lorentz structure, i = S, P, S + P, ... Sizable " T_FS violation" signatures can occur for low-effective mass scales (< 320 GeV), but in most cases can be more simply excluded by 10% precision measurement of the probabilities P(W_L) and P(b_L). Signatures for excluding the presence of " T_FS violation" associated with the two dynamical phase-type ambiguities are investigated.Comment: 15 pages, 1 table, 7 figures, no macro

Heat exchanger with oscillating flow

Various heat exchange apparatuses are described in which an oscillating flow of primary coolant is used to dissipate an incident heat flux. The oscillating flow may be imparted by a reciprocating piston, a double action twin reciprocating piston, fluidic oscillators, or electromagnetic pumps. The oscillating fluid flows through at least one conduit in either an open loop or a closed loop. A secondary flow of coolant may be used to flow over the outer walls of at least one conduit to remove heat transferred from the primary coolant to the walls of the conduit

A Relativistic Quaternionic Wave Equation

We study a one-component quaternionic wave equation which is relativistically covariant. Bi-linear forms include a conserved 4-current and an antisymmetric second rank tensor. Waves propagate within the light-cone and there is a conserved quantity which looks like helicity. The principle of superposition is retained in a slightly altered manner. External potentials can be introduced in a way that allows for gauge invariance. There are some results for scattering theory and for two-particle wavefunctions as well as the beginnings of second quantization. However, we are unable to find a suitable Lagrangian or an energy-momentum tensor.Comment: 19 pages; minor corrections in Section 11 and Appendix

Skylab D024 thermal control coatings and polymeric films experiment

The Skylab D024 Thermal Control Coatings and Polymeric Films Experiment was designed to determine the effects of the external Skylab space environment on the performance and properties of a wide variety of selected thermal control coatings and polymeric films. Three duplicate sets of thermal control coatings and polymeric films were exposed to the Skylab space environment for varying periods of time during the mission. The specimens were retrieved by the astronauts during extravehicular activities (EVA) and placed in hermetically sealed return containers, recovered, and returned to the Wright Laboratory/Materials Laboratory/WPAFB, Ohio for analysis and evaluation. Postflight analysis of the three sets of recovered thermal control coatings indicated that measured changes in specimen thermo-optical properties were due to a combination of excessive contamination and solar degradation of the contaminant layer. The degree of degradation experienced over-rode, obscured, and compromised the measurement of the degradation of the substrate coatings themselves. Results of the analysis of the effects of exposure on the polymeric films and the contamination observed are also presented. The D024 results were used in the design of the LDEF M0003-5 Thermal Control Materials Experiment. The results are presented here to call to the attention of the many other LDEF experimenters the wealth of directly related, low earth orbit, space environmental exposure data that is available from the ten or more separate experiments that were conducted during the Skylab mission. Results of these experiments offer data on the results of low altitude space exposure on materials recovered from space with exposure longer than typical STS experiments for comparison with the LDEF results

Rotational spectrum of cis–cis HOONO

The pure rotational spectrum of cis-cis peroxynitrous acid, HOONO, has been observed. Over 220 transitions, sampling states up to J(')=67 and K-a(')=31, have been fitted with an rms uncertainty of 48.4 kHz. The experimentally determined rotational constants agree well with ab initio values for the cis-cis conformer, a five-membered ring formed by intramolecular hydrogen bonding. The small, positive inertial defect Delta=0.075667(60) amu A(2) and lack of any observable torsional splittings in the spectrum indicate that cis-cis HOONO exists in a well-defined planar structure at room temperature