Designing circuits with partial scan

In this scan design methodology, only selected faults are targeted for detection. These faults are those not detected by the designer's functional vectors. The test generator decides exactly which flip-flops should be scanned using one of two methods. In the first method, all possible tests are generated for each target fault, and the set of tests requiring the fewest flip-flops is selected. In the second method, only one test is generated for each fault, and the use of flip-flops is avoided as much as possible during test generation. Examples of actual VLSI circuits show a savings of at least a 40% in full-scan overhead     

Comparison of capillary gas chromatographic method and automated spectrophotofluorometric methods for measuring content uniformity of conjugated oestrogens in pharmaceutical preparations

To measure the content uniformity of conjugated cestrogens tablets, the USP XXII monograph specifies a capillary gas chromatographic method. This involves separation of the trimethylsilyl derivatives of the various oestrogens found in a typical conjugated oestrogens tablet using a fused-silica 0V 225 bonded phase column. Hydrogen is used as the carrier gas with FID detection. A more rapid spectrophotofluorometric method of analysis has been developed in which the oestrogens are extracted from the dosage form into water, then transferred into organic solvent as the dicyclohexylamine complex. Fluorescence is developed by heating the solution of the complex in the presence of 70% sulphuric acid. The chemistry and detection are carried out using a segmented-flow analyser.The spectrophotofluorometric method is preferred as a routine control for content uniformity because considerable time is saved during sample preparation and analysis compared to gas chromatography. Coefficients of variation show that both methods produce acceptable results. These results fall well within the USP XXII [1] monograph, limits and also well within the tighter limits imposed by the USP XXII, section 905.     

Rainbow Net analysis of VAXcluster system availability

A system modeling technique, Rainbow Nets, is used to evaluate the availability and mean-time-to-interrupt of the VAXcluster. These results are compared to the exact analytic results showing that reasonable accuracy is achieved through simulation. The complexity of the Rainbow Net implemented for the VAXcluster does not increase as the number of processors increases, but remains constant. This is unlike a Markov model which increases in size exponentially. The constancy is achieved by using tokens with identity attributes (items) that can have additional attributes associated with them (features) which can exist in multiple states. The time to perform the simulation increases, but this is a polynomial increase rather than exponential. With Rainbow Nets, there is no restriction on distributions used for transition firing times. This freedom allows real situations to be modeled more accurately by choosing the distribution which best fits the system performance. This eliminates the need to make the many simplifying assumptions that are typically required to keep analytic calculations from becoming intractable     

Multifactorial assessment of bulimia nervosa.

Investigated a multifactorial approach to the assessment of bulimia nervosa by means of hierarchical factor analysis. 245 bulimia nervosa patients and 68 patients with either anorexia nervosa or eating disorders not otherwise specified were administered a self-report battery that was organized into 21 dimensions relevant to eating disorder patients. When dimensions from this battery were subjected to hierarchical factor analysis, support for bulimia nervosa as a unique diagnostic category was obtained. However, the emergence of 3 secondary factors and 6 primary factors suggests that bulimia nervosa can also be described more complexly. The emergence of a multifactorial model of bulimia nervosa that incorporates several existing unidimensional models suggests the potential for both divergent and complicated clinical presentation in bulimia nervosa patients. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Very high-order microring resonator filters for WDM applications

High-order microring resonators having from 1 to 11 coupled cavities are demonstrated. These filters exhibit low loss, flat tops, and out-of-band rejection ratios that can exceed 80 dB. They achieve performance that is suitable for commercial applications.     

Hypervelocity impact computations with finite elements and meshfree particles

The ability of computations to model characteristics of hypervelocity impact is demonstrated using an algorithm for the automatic conversion of distorted finite elements to meshfree particles. The Lagrangian formulation tracks material boundaries and properties without the errors typical in an Eulerian formulation as the material traverses large distances. A computation of a sphere impacting a bumper is shown to reproduce three regions in the debris cloud that are observed in tests: a front region composed of droplets of melted projectile and target, a middle region of fragmented projectile, and a back region of spalled projectile. Additional computations reproduce the observed traits that result from variations in the projectile shape and obliquity. The computation of a projectile impacting spaced plates demonstrates the ability of the method to model the damage to the rear plate of a Whipple shield for spacecraft protection.     

Using rainbow net simulation to measure fault tolerance in a multiprocessor

The Rainbow net simulation technique is applied to modelling the impact of system load and fault handling on the availability of a fault-tolerant multiprocessor architecture. Rainbow nets are described along with the motivation for creating this modelling technique. A Rainbow net fault-handling model is created for the fault-tolerant multiprocessor architecture and the topology is shown to remain constant in size, independent of the number of processor, memory and I/O elements configured in the system. Simulation is performed with a varying load in terms of the number of active jobs the system must support. Results are given showing how the fault-tolerant capability varies with load. Two new metrics for evaluating fault tolerance are introduced; namely full fault-tolerability and partial fault-tolerability. They are based on simple observations in the model.     

Isolation of a non-sedimenting membrane fraction from the water soluble fraction of bovine lens

A membrane fraction was isolated from the water soluble fraction of bovine lens by increasing the density of the water soluble fraction with KBr and subjecting it to overnight centrifugation at 100000 g. We have called this fraction, which floats to the top of the mixture upon centrifugation, the non-sedimenting membrane fraction (NSMF). Electron microscopy of the NSMF revealed that it is composed of the expected membrane structures of unit membrane, fiber junction and cytoskeleton. Significantly less of the total membrane of the NSMF was devoted to fiber junction (22.8%) than in the sedimenting membrane fraction (SMF) (41.1%) prepared by sucrose density centrifugation of the water insoluble fraction. The NSMF accounted for about 7-12% of the total bovine lens membrane, and preliminary experiments demonstrated that a similar fraction could be isolated from the water soluble fraction of lenses from rats, rabbits, chickens and humans. The NSMF contained about 0.9 mg total lipid per mg total membrane protein, which was significantly greater than the value obtained for the SMF (0.5 mg total lipid per mg total membrane protein). The greater relative amount of total lipid in the NSMF was due to a significantly greater relative amount of phospholipid in the NSMF which was further reflected by the observation that the cholesterol: phospholipid molar ration of the NSMF (0.58) was significantly less than that of the SMF (0.88). Thus the relative lipid composition of the NSMF was significantly different than that of the SMF. Although the phospholipid content of the NSMF was greater than that of the SMF, the compositions of the phospholipids in the two membrane fractions were similar. The NSMF possessed essentially the same polypeptides (both extrinsic and intrinsic) which were found in the SMF. The NSMF was found to be distributed throughout the lens in a proportionate manner. We conclude that the NSMF may account for most of the lipid which remains in the water soluble fraction of the normal bovine lens after sedimentation of the water insoluble fraction. This membrane fraction substantially differs from the SMF in terms of structure and relative lipid composition. We speculate that the NSMF may represent a specialised domain of the fiber cell plasma membrane which has been previously unrecognized.     

New intramolecular effect observed for polyesters: An anomeric effect

A series of polyesters was prepared to evaluate hydrolytic stability as a function of cyclohexyl dibasic acid content. The three cyclohexyl dibasic acids: 1,2; 1,3; and 1,4 were formulated into polyesters with two glycols. The proportion of cis and trans isomers was evaluated via ¹H NMR. The hydrolytic stability of short chain polyesters was evaluated in an acetone/water mixture which solubilized the polyesters to mimic oligoester behavior within a thermosetting polyester coating environment. The rate of hydrolysis was monitored by acid titration and corroborated by GPC. Surprisingly, 1,2-cylohexyl diacid-based polyesters were robust, and 1,3-cyclohexyl diacid-based polyesters were the most susceptible to hydrolysis. Evidently, a 1,2-anchimeric effect for cyclohexyl dibasic acid polyesters was not an important consideration, while the 1,3-cyclohexyl ester interaction was. Consequently, an anomeric effect was proposed. Presented at the 81st Annual Meeting of the Federation of Societies for Coatings Technology, November 12–14, 2003, in Philadelphia, PA.