Wafer-scale optimization using computational availability

It is shown that, given the ability to restructure wafer-level designs, there are different ways to employ redundancy. Redundancy is evaluated by estimating system computational availability over a mission lifetime. This technique is illustrated using two wafer-scale integration (WSI) case studies. The first is a very-fine-grained programmable systolic data processor (PSDP) that contains 4- and 8-b paths, RAM, and control optimized for signal and data processing applications. The second, the Mosaic multicomputer architecture, is a less fine-grained homogeneous architecture in which each node contains a 16-b microprocessor and associated RAM and ROM. Potential benefits of implementing these parallel processing architectures in wafer scale are discussed     

Fatigue crack propagation resistance of beta-annealed Ti-6AI-4V alloys of differing interstitial oxygen contents

Fatigue crack growth rates have been determined for beta-annealed Ti-6Al-4V alloys with respective oxygen contents of 0.06, 0.11, 0.18 and 0.20 wt pct. For each of these alloys, transitional crack growth behavior has been observed which appears to correlate with a critical value of the reversed plastic zone size,viz the Widmanstätten packet size. Moreover, growth rates below transitional levels order in terms of packet size, with lower growth rates associated with larger packets. The present results suggest that intersti-tial oxygen content and prior beta grain size significantly affect fatigue crack growth rates through control of the Widmanstätten packet size.     

Quantitative applications of high-resolution proton magnetic resonance measurements in the characterization of detergent chemicals

Quantitative hydrogen nuclear magnetic resonance measurements are used for the determination of average structures of detergent chemicals. For alkylbenzenes, alkylphenols, and ethylene oxide (EO) adducts of alkylphenols, the following quantities can be measured: average lengths of alkyl chains, average molecular weights, degree and kind of branching in the alkyl chain, ortho-para distribution of aryl substituents, and average lengths of BO chains. Accuracy is of the the order of ± 2% of the total hydrogen. The method is nondestructive, and sample volumes as small as 0.007 ml have been used.     

Investigation of chemical rinses suitable for very small meat plants to reduce pathogens on beef surfaces

Numerous antimicrobial interventions are capable of reducing the prevalence of harmful bacteria on raw meat products. There is a need to identify effective and inexpensive antimicrobial interventions that could, in practice, be used in very small meat plants because of limited financial, space, and labor resources. Eight antimicrobial compounds (acetic acid, citric acid, lactic acid, peroxyacetic acid, acidified sodium chlorite, chlorine dioxide, sodium hypochlorite, and aqueous ozone) were applied at various concentrations with small, hand-held spraying equipment, and bactericidal effectiveness was examined. Beef plate pieces were inoculated with fecal slurry containing a pathogen cocktail (Escherichia coli O157:H7, Salmonella Typhimurium, Campylobacter coli, and Campylobacter jejuni) and natural populations of aerobic plate counts, coliforms, and E. coli. Antimicrobial solutions were applied to beef surfaces via a portable, pressurized hand-held spray tank, and treated surfaces were subjected to appropriate methods for the enumeration and isolation of pathogens and hygiene indicators. Relative antimicrobial effectiveness was determined (from greatest to least): (i) organic acids, (ii) peroxyacetic acid, (iii) chlorinated compounds, and (iv) aqueous ozone. Using the equipment described, a 2% lactic acid rinse provided 3.5- to 6.4-log CFU/cm(2) reductions across all bacterial populations studied. Conversely, aqueous ozone yielded 0.02- to 2.9-log CFU/cm(2) reductions in pathogens and hygiene indicators, and did not differ significantly from a control tap water rinse (P = 0.055 to 0.731). This 2% lactic acid rinse will be subsequently combined with a previously described water wash to create a multistep antimicrobial intervention that will be examined under laboratory conditions and validated in very small meat plants.     

Synthesis of biphenylated cyanate esters: Thermomechanical resin comparisons within two isomeric series

Three isomeric tetraaryl cyanate esters containing biphenyl moieties {bis‐[4‐(4′‐cyanatophenyl)phenyl]propane, 2,2‐bis‐[4‐(3′‐cyanatophenyl)phenyl]propane, and 2,2‐bis‐[4‐(2′‐cyanatophenyl)phenyl]propane} and three isomeric triaryl cyanate esters {2‐(4′‐hydroxyphenyl)‐2‐[4′‐(4‐hydroxyphenyl)phenyl]propane, 2‐(4′‐hydroxyphenyl)‐2‐[4′‐(3‐hydroxyphenyl)phenyl]propane, and 2‐(4′‐hydroxyphenyl)‐2‐[4′‐(2‐hydroxyphenyl)phenyl]propane} were synthesized from their corresponding bisphenols. The structures of the monomers were confirmed with IR and ¹H‐NMR spectroscopy. The curing behavior was investigated with differential scanning calorimetry. Cyanate esters were cured thermally in the absence of a catalyst and were characterized by dynamic mechanical analysis. The results were compared to the properties of commercial bisphenol A polycyanurate. Of the three tetraaryl isomers, 2,2‐bis‐[4‐(2′‐cyanatophenyl)phenyl]propane had the highest melting point, and its corresponding resin had the lowest glass‐transition temperature (T_g). The para isomer displayed the highest T_g value of the three novel tetraaryl resins. The triaryl dicyanate isomers were low‐melting solids, with the ortho and meta isomers existing as liquids at room temperature. The T_g value of the para‐triaryl isomer was the highest of the three triaryl isomers and was about the same as that of bisphenol A polycyanurate. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011