Improvement in the bonding strength of laminated composites by using air‐textured core‐and‐effect glass yarns

Delamination is the most common failure mode in laminated composites due to the reduced strength in the through‐the‐thickness direction. Air‐jet texturing was used to produce bulk and loops in the yarn, which provides more surface contact between the fibers and the resin. The development of core‐and‐effect textured glass yarns and the effect of texturing parameters were presented in the previous article. This article describes the effect of texturing on the mechanical properties including tensile properties, flexure properties, interlaminar shear strength (ILSS) and fracture toughness (Mode I) of glass laminated composites. The composites of plain and twill weave fabrics were developed from both the textured and nontextured yarns. It was observed that the tensile properties decreased and the flexure properties remained unchanged after texturing. However, significant improvement was observed in ILSS and the Mode I fracture toughness of the composites after texturing. The bulkier, loopy structure of the textured yarn provided more surface contact between the fiber and the resin and significantly improved the bonding strength. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

Improving the bonding strength of laminated composites by optimizing fabric composition

Delamination is the most common failure mode in laminated composites due to the weaker strength in the through‐the‐thickness direction. Air‐jet texturing is used to produce bulk and loops in the yarn which provides more contact surface between fibers and resin. The development and characterization of core‐and‐effect textured glass yarns and the effect of texturing on the mechanical properties of laminated composites were presented in previous papers. This article describes the optimization of textured composites by varying the type and combination of constituent yarns for improving the mechanical properties. Composites with combinations of various textured yarns and non‐textured yarns were made. It was observed that the composites made from fabrics having non‐textured yarn in the warp and core‐and‐effect textured yarn in the weft had the best combination of mechanical properties. They maintained the tensile and flexure properties of composites with non‐textured yarns but had significantly higher interlaminar shear strength. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

On the Role of Exponential Splines in Image Interpolation

A Sobolev reproducing-kernel Hilbert space approach to image interpolation is introduced. The underlying kernels are exponential functions and are related to stochastic autoregressive image modeling. The corresponding image interpolants can be implemented effectively using compactly-supported exponential B-splines. A tight l₂ upper-bound on the interpolation error is then derived, suggesting that the proposed exponential functions are optimal in this regard. Experimental results indicate that the proposed interpolation approach with properly-tuned, signal-dependent weights outperforms currently available polynomial B-spline models of comparable order. Furthermore, a unified approach to image interpolation by ideal and nonideal sampling procedures is derived, suggesting that the proposed exponential kernels may have a significant role in image modeling as well. Our conclusion is that the proposed Sobolev-based approach could be instrumental and a preferred alternative in many interpolation tasks.     

Analysis and synthesis of multicomponent signals using positivetime-frequency distributions

A new approach to the analysis and reconstruction of multicomponent nonstationary signals from their time-frequency distribution (TFD) is presented. Specifically, we consider a TFD based on the recently introduced minimum cross entropy principle (MCE). This positive TFD is cross-terms free and, hence, has an advantage over the family of bilinear distributions. Based on the MCE-TFD, a new algorithm for reconstructing the phase and amplitude parameters of each component of the signal is developed. To evaluate the accuracy of the algorithm. Monte Carlo simulations are presented and compared with the corresponding Cramer-Rao bound. It is shown that the new algorithm is superior to presently available methods in both efficiency and performance. It is concluded that together with the MCE-TFD representation, the proposed approach provides a powerful tool for analysis of nonstationary multicomponent signals embedded in additive Gaussian noise     

Detection and localization of vapor-emitting sources

We develop methods for detecting and localizing vapor-emitting sources using chemical sensor arrays. Potential applications of these methods include detection of explosives or drugs, sensing leakage of hazardous chemicals or pollution, and studying the environment. We describe the pertinent physical models, develop estimation and detection algorithms, and derive performance bounds. The algorithms are tested numerically and compared with the theoretical bounds     

Taste and aroma of fresh and stored mandarins

During the last decade there has been a continuous rise in consumption of fresh easy‐to‐peel mandarins. However, mandarins are much more perishable than other citrus fruit, mainly due to rapid deterioration in sensory acceptability after harvest. In the current review we discuss the biochemical components involved in forming the unique flavor of mandarins, and how postharvest storage operations influence taste and aroma and consequently consumer sensory acceptability. What we perceive as mandarin flavor is actually the combination of basic taste, aroma and mouth‐feel. The taste of mandarins is principally governed by the levels of sugars and acids in the juice sacs and the relative ratios among them, whereas the aroma of mandarins is derived from a mixture of different aroma volatiles, including alcohols, aldehydes, ketones, terpenes/hydrocarbons and esters. During postharvest storage and marketing there is a gradual decrease in mandarin sensory acceptability, which has been attributed to decreases in acidity and typical mandarin flavor, paralleling an accumulation of off‐flavor. Biochemical analysis of volatile and non‐volatile constituents in mandarin juice demonstrated that these changes in sensory acceptability were concomitant with decreases in acidity and content of terpenes and aldehydes, which provide green, piney and citrus aroma on the one hand, and increases in ethanol fermentation metabolism products and esters on the other, which are likely to cause ‘overripe’ and off‐flavors. Overall, we demonstrate the vast importance of the genetic background, maturity stage at harvest, commercial postharvest operation treatments, including curing, degreening and waxing, and storage duration on mandarin sensory quality. Copyright © 2010 Society of Chemical Industry     

Assessment of Non‐Uniform Sampling Schemes in Solid State NMR of Bacteriophage Viruses

The set of tools offered to NMR spectroscopists has been greatly expanded in the last decades with the development of computer processing power. It has facilitated the use of non‐Fourier transform reconstruction algorithms, leading to the ability to acquire data using non‐uniform sampling. Its use in solid‐state NMR, especially for biological systems, emerges as the next leap toward the analysis and structure prediction of large proteins. Here we applied various non‐uniform sampling schemes to assess their performance towards a three‐dimensional N?C?C correlation experiment aimed to assign chemical shifts in the coat protein of an intact filamentous bacteriophage fd virus. We show that using the sparse multidimensional iterative lineshape‐enhanced (SMILE) reconstruction algorithm, biased sampling increases signal‐to‐noise without compromising linewidths and accuracy of chemical shift determination.     

Cross-cultural differences in resolving union-management conflict through negotiations.

Examined cross-cultural behavioral differences in a conflict resolution situation in Denmark, Spain, Sweden, Switzerland, and the United Kingdom. A union-management negotiation exercise was the basis for the data provided by 260 managers in the 5 countries. The effect of cultural differences on strategy development, negotiating behavior and outcomes, and role perception was examined. Findings point to a relationship between the countries' economic and social environment and behavior in conflict situations. With increase in economic level, an increase in emphasis on welfare benefits and in time needed to resolve the conflict is noticed. Differences between the countries advise against collapsing of samples of geographic proximity or assumed cultural similarities. (22 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)