Use of laser spallation to measure the adhesion of optical fiber coatings

The correlation between chemical effects of some typical optical fiber coating formulations and adhesion to glass was studied by the use of laser spallation. The technique was able to show verifiable differences between dissimilar materials and demonstrated a good correlation to adhesion values determined by mechanical peel testing, and to pullout values measured on coated optical fiber. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2459–2468, 2004     

Möglichkeiten und Grenzen laseroptischer Verfahren zur Untersuchung hydraulischer Strömungsmaschinen

Im Institut für Maschinenkonstruktion der Technischen Universität Berlin, Fachgebiet Hydraulische Strömungsmaschinen und Strömungstechnik, werden seit mehr als zehn Jahren laseroptische Verfahren zur Untersuchung von hydraulischen Strömungsmaschinen eingesetzt. Herkömmliche laseroptische Verfahren wie die Laser-Doppler-Velocimetry gestatten die zeitlich und örtlich hochaufgelöste Untersuchung komplexer instationärer Strömungsvorgänge, wie sie z.B. durch die Wechselwirkung zwischen dem Vorleitrad und Laufrad in vordrallgeregelten axialen Kreiselpumpen auftreten. Die Erfassung von Geschwindigkeitsfeldern ist jedoch bei derartigen Meßsystemen mit punktförmigem Meßvolumen mit einem erheblichen Zeitaufwand verbunden, da die Geschwindigkeitsmessung an den verschiedenen Meßorten nur sequentiell erfolgen kann. Die Entwicklung von Ganzfeldmeßverfahren und deren Applikation in hydraulischen Strömungsmaschinen führt zu einer wesentlichen Reduzierung der Meßzeiten und ermöglicht so die schnelle und detaillierte Untersuchung von real instationären Strömungsvorgängen in Strömungsmaschinen.     

Specification, synthesis, and verification of hazard-free asynchronous circuits

This article describes three aspects of asynchronous design from a Petri-net specification called asignal transition graph (STG). First, we show that the STG defined by Chu [1] is too restrictive for specifying general asynchronous behavior and propose extensions to the STG which allow for more general and compact representation. Second, we show that syntactic constraints on STGs are not sufficient to guarantee hazard-free implementations under the unbounded gate delay model, and present techniques to synthesize two-level implementations which are hazard-free under the multiple signal change condition. To remove all hazards under the multiple signal change condition, the initial specification may need to be modified. Finally, we show that behavior containment test using the event coordination model [2] is a powerful tool for the formal verification of asynchronous circuits. This verification method can provide sanity checks for all synthesis methods that use the unbounded gate delay model, and provides a mechanism for designers to validate some manual gate-level changes to the final design.     

Boundary element method for membrane and torsion crack problems

Here we present as an application of [12] an improved Galerkin method for the boundary integral equations governing a plane interface problem. Membrane and torsion crack problems can be treated by slight modifications.A tedious analysis incorporating the Mellin transform shows that the coupled system of integral equations—with some Fredholm equations of the second kind and some of the first kind—on the boundary curve Γ is strongly elliptic, i.e., there holds a Gårding inequality. This property implies convergence of almost optimal order of the Galerkin procedure. The use of singularity functions together with regular finite elements on Γ provides convergence results in a scale of Sobolev spaces and even quasi-optimal asymptotic error estimates for the stress intensity factors. These factors are computed directly by our Galerkin scheme, i.e., no additional computations are needed.The Galerkin method is implemented by an appropriate numerical integration leading to a Galerkin collocation. The latter is a modified collocation method which can be easily implemented on computing machines.     

Parental relationships and early social experiences of activist male homosexuals and male heterosexuals.

Compared questionnaire data from a sample of 88 young activist male homosexuals and a control sample of 105 male heterosexuals on variables relating to parental relationships and early social experiences. Samples were similar with respect to age, father's occupation, and religion. Results indicate that the homosexuals came from families in which the mothers were more dominant and affectionate than the fathers. Masculine role behavior was not encouraged by either parent and positively evaluated masculine models were generally less available for homosexuals than for heterosexuals. As children, the homosexuals were shy, effeminate loners who interacted more with females-mothers, sisters, and friends-than males. As adolescents, the homosexuals engaged in less heterosexual sexual behavior than the heterosexuals. Results were compared with findings from previous studies in which different samples and methods were used. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of intraparticle total pressure change on pore mass transport

Influence of intraparticle total pressure change on pore mass transport is investigated in physical gas phase adsorption of a single component from an inert carrier medium. The Dusty Gas Model is applied to quantify pore mass transport, assuming local equilibrium between pore fluid and adsorbed phase. Calculated results for single pellet adsorption kinetics of cyclohexane on activated carbon and CO₂ on molecular sieve 5 Å are compared with experimental data. It is found that the total pressure drop in the pore system may be as much as 1% of the ambient total pressure. This results in a maximum viscous flow contribution of 13% for the cases studied. Since this contribution is obtained only under conditions of low overall transport rates of the adsorbed component, the assumption of isobaric conditions within the pore system of a porous adsorbent appears justified for most cases of practical calculations.     

Absolute quantification of monoclonal antibodies in biofluids by liquid chromatography-tandem mass spectrometry

The development of a quantification method for monoclonal antibodies in serum has been accomplished by high-performance liquid chromatography multiple reactions monitoring mass spectrometry. A human monoclonal antibody (HmAb) was used as the model protein for method development and validation. A peptide from the CDR3-region of its heavy chain was selected and used for quantifying the entire mAb. This signature peptide served as a template for the internal standard. Prior to mass spectrometric analysis approximately 50% of the total serum protein content was removed by albumin depletion. The accuracy of the method ranged between 99 and 112% in cynomolgus monkey serum. The intra-assay coefficient of variation (CV) was lower than 4% at 4 microg/mL and 200 microg/mL HmAb (n = 3). The CV at 400 microg/mL corresponded to 9% (n = 3). In addition, the interassay variation was investigated in a male cynomolgus serum pool and in a female cynomolgus serum pool. The CV for the male cynomolgus pool at 4 microg/mL HmAb was 7% (n = 3). The CV obtained from the female pool was 8% (n = 3), at 4 microg/mL. The dynamic range of the method was 3 orders of magnitude. After albumin depletion of 25 microL of serum, a lowest limit of quantification of 2 microg/mL HmAb was reached in both human and cynomolgus monkey samples.