NIST reference goniophotometer for specular gloss measurements

The measurement of specular gloss consists of comparing the luminous reflectance from a test specimen to that from a gloss standard, under the same geometric conditions. The reference goniophotometer described here was designed and characterized to comply with the geometric and spectral conditions specified in the international documentary standards for specular gloss measurements at the standard geometries of 20, 60, and 85°. In addition, this instrument measures the bi-directional luminous reflectance and transmittance for incident angles from 0 to 85°. The goniophotometer and the measurement procedures used to determine the specular gloss of nonmetallic samples are described in this paper, as well as the characterization of the instrument and uncertainty analysis. The minimum relative expanded uncertainty (k=2) for the reference goniophotometer is 0.3%. Optical Technology Div., Gaithersburg, MD 20899-8441.     

The economics of system-level testing

Competitive pressure to streamline system-level test without affecting product quality is mounting. Identifying the features unique to system-level testing, the authors present key results of production testing based on a new test cost model     

Agile model driven development is good enough

I'm not all that sure about the direction that model-driven development appears to be taking. Don't get me wrong-I'm a firm believer in modeling. It's just that I think that there's a lot more to development than this. Here's my point: We need to distinguish between generative MDD and Agile MDD. Generative MDD, epitomized by the Object Management Group's Model Driven Architecture, is based on the idea that people will use very sophisticated modeling tools to create very sophisticated models that they can automatically "transform" with those tools to reflect the realities of various deployment platforms. Great theory-as was the idea that the world is flat. In my opinion, generative MDD is a lost cause for the current generation of developers. Agile MDD will be a struggle to pull off, but at least it has a chance of succeeding.     

Randomly branched styrene/divinylbenzene copolymers. I. Preparation,molecular weight characterization,and GPC analysis

A series of randomly branched copolymers of styrene and divinylbenzene were prepared using a benzoyl peroxide-initiated free-radical bulk polymerization at 78°C. DVB contents were varied from 0.01% to 2%. Two samples were polymerized with 0.4% DVB to different conversions: series 9A at 6% conversion and series 9B at 15% conversion (just short of the gelation point). Both samples were fractionated and the fractions characterized by ultracentrifugation, light scattering, osmometry, viscometry, and gel permeation chromatography. The data indicated that the fractions were not of narrow MWD and that the breadth of the MWD of the fractions from series 9B were greater than those of 9A. GPC calibration curves of M, [η], and M [η] were generated for both 9A and 9B fractions by employing curve-fitting techniques to the GPC data. For all of the fractions 9B, the molecular weight calibration provided accurate values of M?_z, M?_w, and M?_n, suggesting that no serious peak spreading had occurred in the GPC experiments. The universal calibration parameter M[η] for the 9A fractions agreed with that of linear polystyrene, while that of the high-conversion series 9B did not. It will be shown in a later paper that series 9B is highly branched, while 9A is lightly branched. Consequently, it is recommended that any GPC analysis of branching units make an allowance for the deviation of highly branched polymers from the linear M[η] calibration curve.     

Sensitivity analysis in economics based test strategy planning

This article will present methods to analyze the sensitivity of test costs to the inaccuracy of the individual costing parameters. The results show that a few parameters—e.g., the gate count—need very detailed estimates, whereas the accuracy of many other parameters is insignificant in 99% of all cases. The techniques presented allow an in-depth evaluation of what is perceived as the main drawback in the use of economic modeling methods, namely, the element of risk associated with inaccuracies in the input data.     

Relationship between perceptual style and reactivity to motion.

The relationship between the perceptual-style dimension of field dependence-independence, as measured by the rod-and-frame test (RFT) and the group Hidden Figures Test, and motion disturbance, as evidenced by a version of the Brief Vestibular Disorientation Test (BVDT) was investigated in 83 naval aviation students. Significant correlations were found between RFT scores and BVDT scores. Field dependence was significantly associated with disturbance by the motion stimulus of the test. Apparent contradictions of the present findings with those involving simulator sickness are discussed. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The ultrafiltration of solutions of polymers containing microgel

The use of ultrafiltration in determining microgel contents of synthetic rubbers containing high levels of microgel was extensively studied. From experiments with a nonagitated filtration cell, it was found that accurate microgel contents could be obtained only when concentration polarization of the membrane was disallowed. GPC studies of the filtrates indicated that changes in the molecular weight distribution of the filtered polymer occured as a result of the occurrence of concentration polarization. The use of an agitated filtration cell was found to inhibit the occurrence of concentration polarization, allowing the proper filtration of larger volumes and higher concentrations of solutions of these types of polymers.     

Synthesis and characterization of near monodisperse oligomeric polystyrenes

Oligomeric (<10³) polystyrenes have been synthesized on a practical scale by the use of secbutyllithium and triethylamine in cyclohexane. These samples were found to possess relatively narrow molecular weight distributions. The product analysis was accomplished by viscosity, vapour pressure osmometry, gel permeation chromatography and gas chromatography.