A variable radius roll adhesion test (VaRRAT) suitable for measuring the adhesion of paint to metal

Early trials and analysis of a new adhesion test are discussed. The test is designed for measuring the adhesion of paint to deformable steel sheets as used in building, automotive, and other cladding applications, and does not require detailed knowledge of the paint mechanical properties. A stiff overlay, such as an epoxy resin, is applied to the coating, and the steel substrate is peeled away using a roll of well-defined radius to which the steel substrate is constrained. The propagation of a crack within the paint or at some interface in the paint/metal system depends mostly on the mechanical properties and thickness of the overlay and the radius of the constraining roll. The test is shown to discriminate better than existing practical adhesion tests between paints of expected differing adhesion/cohesion, but also presents some inconsistencies that require further work to resolve. BHP Institute of Steel Processing and Products, Wollongong NSW 2522, Australia.     

Behavior of a Semiintegral Bridge Abutment under Static and Temperature-Induced Cyclic Loading

This paper presents the results of an experimental study of semiintegral bridge abutments. Primary interests were to investigate (1) potential problems with the particular detail tested; (2) rotational characteristics of the semiintegral abutments; and (3) ability of the specimens to withstand cyclic loading induced by temperature variations during the expected life of the bridge. Sixteen experiments were conducted on three large-scale specimens. The results of the tests have shown that semiintegral abutments can significantly reduce the moments transferred from the superstructure to the foundation piles. Test results have also shown that semiintegral abutments can tolerate the number of displacement cycles that a bridge will experience during the course of its economic life.     

Correlation of vibrational intensity with fluorescence lifetimes in π conjugated polymers

A series of novel pi (π) conjugated polymers, originating from the archetypical Polyphenylene vinylene, in which the phenyl units are successively replaced by the larger naphthyl and anthryl acene units, were previously found to have a well-defined relationship between their relative fluorescence yields and their vibrational characteristics, as determined by Raman spectroscopy. In this study the Strickler-Berg equation is used to probe the influence of continual substitution of higher order acene units into the conjugated backbone in terms of the variation of the radiative and non-radiative rates. The deconvolution of the radiative and non-radiative rates enables the correlation of the reduction of the Raman intensity and concomitant increase in the fluorescence yield with the reduction of the non-radiative rate. This confirms that the reduction of the non-radiative rate is the dominant process introduced by the vibrational confinement originating from systematic substitution of higher order acene units into the polymer backbone.     

Rotational Restraint of Pile Caps during Lateral Loading

A pure fixed-head (zero-rotation) condition at the top of a group of laterally loaded piles is seldom achievable in the field, even when piles are installed in a group that is “rigidly” constrained by a stiff concrete pile cap. Assuming complete fixity during design (zero rotation at the pile head) can result in underestimated values of pile-head deflection, and incorrect estimates of the magnitude and the location of maximum bending moments. A simple and practical approach is presented for estimating the moment restraint that is provided by the pile cap at the top of a pile group. The moment restraint, represented by the rotational restraint coefficient (KMθ), serves as a boundary condition for analyzing groups of laterally loaded piles. Full-scale field tests performed on two pile groups with concrete pile caps show that the proposed method for estimating rotational restraint provides results that are in good agreement with measured field performance.     

Flavor Fade in Peanuts During Short-term Storage

ABSTRACT: Flavor characteristics of roasted peanuts over short-term storage were explored through sensory and chemical analyses. The volatiles from freshly roasted peanuts were evaluated over short-time (21 d) storage using gas chromatography, chemosensory techniques, and a sensory panel to quantify and identify pyrazines and hexanal over a 21-d storage period. A significant decrease ( P < 0.05) was noted in 2,3-diethylpyrazine, 2-methoxypyrazine, 2,3-dimethylpyrazine, 2-ethyl-3-methylpyrazine, and 2,3,5-trimethylpyrazine concentrations over a 21-d period. No significant difference ( P > 0.05) was noted in the 2-methylpyrazine and 2-ethylpyrazine concentrations. The hexanal concentration significantly increased ( P < 0.05) over the 21-d period. The peroxide values and sensory analysis agreed with these results. A significant increase ( P < 0.05) in peroxide value was seen at days 14 and 21, and a significant decrease ( P < 0.05) in fresh roasted peanuty flavor from day 0 to 21 and significant increases ( P < 0.05) in painty, cardboardy, and bitter flavors from day 7 to 21 with the sensory analysis. The electronic nose successfully separated day 0 and 21 samples from day 7 and 14 samples, which were also separated but with some overlap.     

100 mK bolometers for the submillimetre common-user bolometer array (scuba) I. Design and construction

We describe the design and construction of bolometric detectors for SCUBA - the Submillimetre Common-User Bolometer Array for the James Clerk Maxwell Telescope in Hawaii. The instrument contains 131 individual detectors, in two arrays, optimized for the submillimetre atmospheric transmission windows. The detectors are cooled by dilution refrigeration to a temperature of 100 mK, so that the receiver performance will be limited by photon noise from the sky and telescope background in all wavebands. A future paper will describe the performance of the detectors with reference to typical data obtained during the laboratory commissioning period.     

Predictive modelling of the 3-D structure of interleukin-13

Several atomic structures are now available for the family ofhelical cytokines, which includes growth hormone as well asmany of the interleukins. Using structural information fromfive members of this family, two alternative models of interleukin(IL)-13 are proposed. IL-13 has biological properties similarto those of IL-4 and, like the other interleukins, is a potentiallyimportant pharmaceutical target. The model of IL-13 is discussedand compared with the known interleukin structures.     

The cement mantle in the Exeter impaction allografting technique. A cause for concern

The postoperative radiographs of 35 patients who underwent impaction allografting of the proximal femur were reviewed. Of Gruen zones that could be clearly visualized, 39.9% contained areas where cement was absent. Even when an adequate mantle was present, cement voids were commonly seen. These cement mantle deficiencies were confirmed in a series of cadaveric impaction allografting procedures. They appear to be a consequence, at least in part, of an inadequate differential between trial and actual component sizes. Additionally, 4 patients were identified with significant component migration secondary to radiographically visible cement mantle fractures within the first 6 months of surgery. It is concluded that the surgical technique requires modification to ensure a more consistent cement mantle and clinical result.     

Control theory methods for consistency in some least squaresidentification problems

The consistency of a family of least-squares estimates of some unknown parameters of a continuous-time linear stochastic system is verified. The unknown parameters appear affinely in the linear transformations of the state and the control. The method of verification of consistency associates a family of control problems to the identification problem, and the asymptotic behavior of the solutions of a family of algebraic Riccati equations from the control problems implies a persistent excitation property for the identification problem     

Acoustic emission calibration instrumentation

An automatic calibration instrument was developed to improve the calibration accuracy of acoustic emission (AE) instrumentation. The instrument facilitates calibration by automatically displaying the maximum value of the stress used to produce AE calibration pulses and the AE pulse. A repeatable AE signal was generated by breaking a graphite rod on the test assembly. By measuring the breaking load of the rod and the maximum root-mean-square values of the resulting AE signals, a relative calibration of the AE measurement system was achieved. Low-noise amplifiers and filters were developed to improve the sensitivity of AE measurements by more than one order of magnitude over commercially available instruments; thus, the smaller signals obtained in parts testing can be detected