THE VALUE OF AGEING THE TERRA COTTA BODY1

It is shown that the terra cotta body when aged for a period of twelve days improves in plasticity, workability and strength. If the body is aged and subsequently repugged, still greater improvement is noted. This process is recommended as developing to the fullest extent the latent qualities of the body. The theory of this action seems to be a softening of the clay grains which with the retempering process results in a finer subdivision of the particles and a more intimate combmation of the clay and grog.     

Note: A heated-air curtain design using the Coanda effect to protect optical access windows in high-temperature, condensing, and corrosive stack environments

We present an air knife design for creating a heated air curtain to protect optical infrared access windows in high-temperature, condensing, and corrosive stack environments. The design uses the Coanda effect to turn the air curtain and to attach the air curtain to the window surface. The design was tested and verified on our 24 m stack and used extensively over a 6 yr period on several release stacks. During testing and subsequent use no detrimental changes to access window materials have been noted. This design allows stack monitoring without significantly affecting the stack flow profile or chemical concentration.     

Anaerobic biological treatment of phenolic wastewater at 15-18 degrees C

Low-temperature, or psychrophilic (<20 degrees C) anaerobic digestion has been proven feasible for the mineralisation of simple wastewaters. In this study, hybrid expanded granular sludge bed-anaerobic filter (EGSB-AF) bioreactors were used to evaluate the feasibility of psychrophilic digestion for the treatment of phenol-containing wastewater. Efficient chemical oxygen demand and phenol removal were observed at organic and phenol loading rates of 5 kg COD m(-3)d(-1) and 0.4-1.2 kg phenol m(-3)d(-1) (400-1200 mg phenol [l wastewater](-1)), respectively. There was no long-term accumulation of volatile fatty acids in the reactor systems. Methanogenic activity was developed under psychrophilic conditions but anaerobic methane-producing populations remained mesophilic throughout the trial of 415 days.     

Predictive study of charge transport in disordered semiconducting polymers

We present a theoretical study of charge transport in disordered semiconducting polymers that relates the charge mobility to the chemical structure and the physical morphology in a novel multiscale approach. Our studies, focusing on poly(9,9-dioctylfluorene) (PFO), show that the charge mobility is dominated by pathways with the highest interchain charge-transfer rates. We also find that disorder is not always detrimental to charge transport. We find good agreement with experimental time-of-flight mobility data in highly aligned PFO films.     

Dynamic emulation of mechanical loads using a vector-controlledinduction motor-generator set

This paper addresses the problem of electronic emulation of both linear and nonlinear mechanical loads using a vector-controlled induction machine dynamometer. It is shown that a basic emulation scheme where the dynamometer torque demand is derived from the inverse dynamics of the emulated load is not generally viable, especially if the emulated load is part of a closed-loop speed control system. A new feedforward speed-tracking control scheme for the dynamometer is presented, which preserves the load dynamics and allows for emulation of a large class of nonlinear loads. An experimental rig is described using vector-controlled induction machines as the drive motor and dynamometer, and experimental results showing excellent emulation of both linear and nonlinear load dynamics are presented     

Liquid-crystalline semiconducting polymers with high charge-carrier mobility

Organic semiconductors that can be fabricated by simple processing techniques and possess excellent electrical performance, are key requirements in the progress of organic electronics. Both high semiconductor charge-carrier mobility, optimized through understanding and control of the semiconductor microstructure, and stability of the semiconductor to ambient electrochemical oxidative processes are required. We report on new semiconducting liquid-crystalline thieno[3,2-b ]thiophene polymers, the enhancement in charge-carrier mobility achieved through highly organized morphology from processing in the mesophase, and the effects of exposure to both ambient and low-humidity air on the performance of transistor devices. Relatively large crystalline domain sizes on the length scale of lithographically accessible channel lengths ( approximately 200 nm) were exhibited in thin films, thus offering the potential for fabrication of single-crystal polymer transistors. Good transistor stability under static storage and operation in a low-humidity air environment was demonstrated, with charge-carrier field-effect mobilities of 0.2-0.6 cm(2) V(-1) s(-1) achieved under nitrogen.     

Resting developments: a review of fMRI post-processing methodologies for spontaneous brain activity

Analytic tools for addressing spontaneous brain activity, as acquired with fMRI during the "resting-state," have grown dramatically over the past decade. Along with each new technique, novel hypotheses about the functional organization of the brain are also available to researchers. We review six prominent categories of resting-state fMRI data analysis: seed-based functional connectivity, independent component analysis, clustering, pattern classification, graph theory, and two "local" methods. In surveying these methods, we address their underlying assumptions, methodologies, and novel applications.     

Ratiometric fluorescence detection of mercury ions in water by conjugated polymer nanoparticles

We present dye-doped polymer nanoparticles that are able to detect mercury in aqueous solution at parts per billion levels via fluorescence resonance energy transfer (FRET). The nanoparticles are prepared by reprecipitation of highly fluorescent conjugated polymers in water and are stable in aqueous suspension. They are doped with rhodamine spirolactam dyes that are nonfluorescent until they encounter mercury ions, which promote an irreversible reaction that converts the dyes to fluorescent rhodamines. The rhodamine dyes act as FRET acceptors for the fluorescent nanoparticles, and the ratio of nanoparticle-to-rhodamine fluorescence intensities functions as a ratiometric fluorescence chemodosimeter for mercury. The light harvesting capability of the conjugated polymer nanoparticles enhances the fluorescence intensity of the rhodamine dyes by a factor of 10, enabling sensitive detection of mercury ions in water at levels as low as 0.7 parts per billion.     

Comparison of probability density functions for analyzing irradiance statistics due to atmospheric turbulence

A large number of model probability density functions (PDFs) are used to analyze atmospheric scintillation statistics. We have analyzed scintillation data from two different experimental setups covering a range of scintillation strengths to determine which candidate model PDFs best describe the experimental data. The PDFs were fitted to the experimental data using the method of least squares. The root-mean-squared fitting error was used to monitor the goodness of fit. The results of the fitting were found to depend strongly on the scintillation strength. We find that the log normally modulated Rician and the log normal PDFs are the best fit to the experimental data over the range of scintillation strengths encountered.