The Wear of PTFE-Containing Dry Bearing Liners Contaminated by Fluids

The influence of fluid contamination on the wear of a number of aircraft dry bearing liners has been examined using a recently developed, accelerated test procedure. It is shown that fluids generally increase wear to an extent depending on the level of stress, the type of fluid and the structure and composition of the liner material. Water is invariably deleterious but, at low stresses, mineral and diester oils can sometimes reduce the wear rate below that obtained in dry conditions. Explanations for the trends observed are deduced from a detailed examination of worn surfaces by X-ray photo-electron spectroscopy (XPS) and scanning electron microscopy (SEM). The relevance of the results to current specification requirements for aircraft dry bearings is discussed, and a number of inadequacies exposed.     

Determining the damping factor of sedimentary rocks required for seismically designed structures

Relationships for the shear damping ratio D_s (a function of shear quality factor Q_s) and modulus decay curve G_seis/G_max as a function of shear strain for mudrocks have been developed. Field experiments to determine damping ratio and elastic moduli should be performed at frequencies as close as possible to the bandwidth (0–100 Hz) of interest for building design. Estimates of these parameters made from extrapolating laboratory core (MHz) or wireline (kHz) data to lower frequencies can be highly unreliable. Field estimates of damping ratio are very dependent on, and often totally dominated by, the effects of scattering of P and S waves by inhomogeneities in the rock mass structure. This is, particularly, the case when open fractures or cracks are present in near-surface rocks.     

永远优美的传说——FALCOM伊苏系列

说起与《伊苏》的缘分，大概要追溯到十多年以前。     

Control of Nanoscale Environment to Improve Stability of Immobilized Proteins on Diamond Surfaces

Immunoassays for detection of bacterial pathogens rely on the selectivity and stability of bio-recognition elements such as antibodies tethered to sensor surfaces. The search for novel surfaces that improve the stability of biomolecules and assay performance has been pursued for a long time. However, the anticipated improvements in stability have not been realized in practice under physiological conditions because the surface functionalization layers on commonly used substrates, silica and gold, are themselves unstable on time scales of days. In this paper, we show that covalent linking of antibodies to diamond surfaces leads to substantial improvements in biological activity of proteins as measured by the ability to selectively capture cells of the pathogenic bacterium Escherichia coli O157:H7 even after exposure to buffer solutions at 37 °C for extended periods of time, approaching 2 weeks. Our results from ELISA, XPS, fluorescence microscopy, and MD simulations suggest that by using highly stable surface chemistry and controlling the nanoscale organization of the antibodies on the surface, it is possible to achieve significant improvements in biological activity and stability. Our findings can be easily extended to functionalization of micro and nanodimensional sensors and structures of biomedical diagnostic and therapeutic interest.     

Process modeling of the low‐temperature evolution and yield of polycarbosilanes for ceramic matrix composites

The volatilization of polycarbosilanes is important to the processing and performance of polymer infiltration and pyrolysis‐based ceramic matrix composites. Low molecular weight (MW) polycarbosilane is often present in preceramic polymers and enhances viscosity for the purpose of composite infiltration. Due to the volatility of low MW chains, a model was developed to semi‐empirically determine the MW distribution and then predict the mass yield and evolution of the MW distribution as a function of temperature and time for StarPCS^? SMP‐10. The enthalpy of vaporization, the temperature dependence of the enthalpy of vaporization, the temperature dependence of the normal boiling point and a representation of the molecular weight distribution were fit using a series of thermogravimetric measurements, involving isothermal holds on a particular batch of SMP‐10. Once calibrated for SMP‐10 in this fashion, the molecular weight distribution of different batches of SMP‐10 could be fit using a thermogravimetric measurement involving a reduced temperature‐time series. The model was then predictive of mass loss over time for temperatures below the onset of curing (>90°C). Understanding this volatilization enables improved SiC yield, reduced processing time and minimizing void/bubble formation.     

Solubility and solution thermodynamic properties of quercetin and quercetin dihydrate in subcritical water

Fundamental physicochemical data is required for the design and optimization of food engineering processes, such as extraction. Flavonoids are present in natural products such as grapes and have numerous health benefits particularly with respect to their reported antioxidant properties. Such flavonoid compounds can be extracted from these natural products using a variety of solvents, among them water. In this study, the aqueous solubilities of 3,3′,4′,5,7-pentahydroxyflavone (quercetin) and its dihydrate were measured at temperatures between 25 and 140 °C using a continuous flow type apparatus. The flow rate of subcritical water was studied at 0.1, 0.2 and 0.5 mL/min to study its effect on quercetin solubility and thermal degradation at temperatures greater than 100 °C. The aqueous solubility of anhydrous quercetin varied from 0.00215 g/L at 25 °C to 0.665 g/L at 140 °C and that of quercetin dihydrate varied from 0.00263 g/L at 25 °C to 1.49 g/L at 140 °C. The aqueous solubility of quercetin dihydrate was similar to that of anhydrous quercetin until 80 °C. At temperatures above or equal to 100 °C, the aqueous solubility of quercetin dihydrate was 1.5–2.5 times higher than that of anhydrous quercetin. The aqueous solubility of quercetin anhydrate and dihydrate at different temperatures was correlated using a modified Apelblat equation. The thermodynamic properties of the solution of quercetin and its dihydrate in water were than estimated from their solubility values. A flow rate effect on the aqueous solubility of quercetin and its dihydrate was not observed until above 100 °C where higher solvent (water) flow rates (>0.1 mL/min) were required to maintain a constant solubility in the saturation cell and with minimal thermal degradation of the solute (quercetin dihydrate). The study of its particle morphology under SEM indicated an aggregation of the crystals of quercetin dihydrate at subcritical water temperatures and at lower flow rates (<0.5 mL/min), thereby inhibiting stable solubility measurements and solvent flow through the saturation cell.     

Positive affect, intuition, and feelings of meaning.

Subjective rationality, or the feeling of meaning, was identified by William James (1893) as a central aspect of the non-sensory fringe of consciousness. Three studies examined the interaction of positive affect (PA) and individual differences in intuitive information processing in predicting feelings of meaning for various stimuli and life events. In Study 1 (N = 352), PA and intuition interacted to predict understanding for ambiguous quotes and abstract artwork. In Study 2 (N = 211), similar interactions were found for feelings of meaning for fans after their football team lost a conference championship game and for individuals not directly affected by Hurricane Katrina in events surrounding the hurricane. In Study 3 (N = 41), induced PA interacted with individual differences in intuition in predicting accuracy for coherence judgments for loosely related linguistic triads. Intuitive individuals in the positive mood condition recognized coherent triads more accurately than did other participants. Results are discussed in terms of the role of individual differences in intuitive information processing in the relationship of PA to cognition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Dynamic Shape Factor of Sodium Chloride Nanoparticles as Regulated by Drying Rate

The influence of drying rate on the dynamic shape factor χ of NaCl particles was investigated. The drying rate at the efflorescence relative humidity (ERH) of 45% was controlled in a laminar flow tube and varied from 5.5 ± 0.9 to 101 ± 3 RH s^–1 at ERH, where RH represents one percent unit of relative humidity. Dry particles having mobility diameters of 23–84 nm were studied, corresponding to aqueous particles of 37–129 nm at the RH (57%) prior to drying. At each mobility diameter and drying rate, the critical supersaturation of cloud-condensation activation was also measured. The mobility diameter and the critical supersaturation were combined in an analysis to determine the value of χ. The measured values varied from 1.02 to 1.26. For fixed particle diameter the χ value decreased with increasing drying rate. For fixed drying rate, a maximum occurred in χ between 35- and 40-nm dry mobility diameter, with a lower χ for both smaller and larger particles. The results of this study, in conjunction with the introduced apparatus for obtaining quantified drying rates, can allow the continued development of a more detailed understanding of the morphology of submicron salt particles, with the potential for the follow-on development of quantitative modeling of evaporation and crystal growth at these dimensions.     

Structural brain correlates of verbal and nonverbal fluency measures in Alzheimer's disease.

This study examined the relationships between regional brain volumes and semantic, phonological, and nonverbal fluency in 32 participants with Alzheimer's disease (AD). Object but not animal semantic fluency correlated with frontal and temporal gray matter volumes. Phonological fluency was not significantly associated with any brain volume examined. Nonverbal fluency was selectively associated with bilateral frontal gray matter volumes. Hippocampal volumes, although markedly reduced in these patients, were not related to any of the fluency measures. Results lend evidence to the importance of the frontal lobes in the directed generation of nonverbal and verbal exemplars by AD patients. Furthermore, both left and right-hemisphere regions contribute to the generation of verbal and nonverbal exemplars. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Managing a multiple relationship environment: The ethics of military psychology.

Military psychologists often find themselves in situations having the potential to compromise their professional ethics. Although conflicts in confidentiality are frequently the issue, multiple relationship development is also a significant concern. Case examples involving multiple relationship issues are presented, and the American Psychological Association's (APA's; 1992) guidelines concerning multiple relationship expectancies are considered. Decision-making frameworks are reviewed, and an adaptation of M. C. Gottlieb's (1993) model for multiple relationship resolution is proposed. The authors suggest recommendations for training and supervision, and they encourage continued collaboration between the APA and Department of Defense so that these dilemmas may be more adequately addressed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)