Synthesis and Characterization of Alkyl-Bridged Bicycloheptanes as Traction Fluids

The traction fluid is a critical component of a toroidal-continuously variable transmission (T-CVT). As the medium that transmits power through the toroids, the traction fluid needs to provide a high traction coefficient and retain low dynamic viscosity at cold temperatures; this is a challenging combination of properties. A comparison of a variety of fluids shows a broad correlation between the traction coefficient and the fluid's low temperature viscosity, or pour point. This work investigated a series of novel compounds as traction fluids through chemical synthesis and the measurement of their relevant physical properties. Specifically, four new alkyl-bridged bicycloheptane fluids have been synthesized and refined to high purity. Their traction coefficients, measured with a ball-on-disc traction apparatus, are comparable to those of commercial fluids over the relevant range of temperature and pressure. Their dynamic viscosities at low temperature, however, are higher than the viscosity of commercial fluids and exceed the value of 3 × 10 ⁴ cP at ?40°C. These bridged bicycloheptanes also exhibit a correlation between their low-temperature viscosity and traction coefficient. The reasons for this correlation are discussed, and the effect of the molecular structure on viscosity and traction coefficient is investigated. This analysis finds semi-quantitative relationships between fluid properties and the molecule's volume, stiffness, and ring structure.     

Comparison theorems for set stability of differential equations

Set stability and uniform set stability of differential equations involve known specific bounds on solutions of the differential equations under consideration. Comparison theorems are presented giving sufficient conditions for these forms of stability. The conditions include the existence of a Liapunov-Like function and the set stability of a scalar differential equation. Examples are given to demonstrate the method.     

Computer-modelled deformation mechanism maps for hot uniaxially pressed Bi-2223 superconductor

A deformation mechanism map represents the densification behaviour of a green powder body. A map is created by evaluating the rate-equations for five types of densification mechanisms: yield, boundary diffusion, volume diffusion, power-law creep, and Nabarro–Herring creep. These rates are summed where appropriate and integrated to give the density at a given pressure, temperature and time; this can then be plotted on a map. Such maps have been created for hot-pressed Bi-2223, using the HIP 6.0 computer software. Four temperature–density deformation maps were created at different pressing pressures and for two types of powder: a solid-state reacted powder and a pyrolysed organic precursor powder. The resulting maps are compared and discussed in relation to a set of experimental results. This revised version was published online in November 2006 with corrections to the Cover Date.     

Nutrient issues on Irish farms and solutions to lower losses

Agriculture in Ireland utilizes 63% of total land area and has a big environmental impact accounting for 70% of phosphorus and 82% of nitrogen in surface waters, and for 97% of ammonia, 81% of nitrous oxide and 86% of methane emissions to air. Phosphorus loss to water is Ireland's most serious pollution problem. The deterioration of water quality that has been evident since the 1970s has been halted and reduction targets for ammonia and greenhouse gas emissions from agriculture are being achieved. These achievements are largely attributable to declining ruminant livestock populations and declining inputs of manufactured fertilizers as a result of increasing emphasis on extensification of production practices in the Common Agricultural Policy during the past decade. Nevertheless, substantial improvements in water quality are needed by 2015 to meet the requirements of the Water Framework Directive. To meet this and a broad range of environmental targets and to comply with the Nitrates Directive, a wide ranging set of regulations governing agricultural practices was implemented into law in 2006. These include general limits on stocking rates on farms of no greater than 170 kg/ha of N in livestock manures applied mechanically or deposited by grazing livestock. There are periods between September and January when the application of fertilizers and manures is prohibited and minimum winter storage requirements apply for manures generated on farms of between 16 and 26 weeks depending on location and agricultural enterprise. The use of phosphorous is stringently curtailed; there are limits on phosphorous concentrations in soil as determined by a soil test and limits on imports of phosphorus onto farms, which generally cannot exceed exports. These regulations are likely to make an important contribution to achieving environmental targets in Ireland, particularly the improvement in water quality required by the Water Framework Directive.     

Effects of Pretreatment and Dehydration Temperature on Color, Nutrient Retention and Sensory Characteristics of Okra

Moisture content, water activity, color, and concentrations of ascorbic acid and thiamin of blanched (boiling water with or without 0.1% SO₂) and unblanched okra, dried for 10 hr at 63°C or 14 hr at 52°C, were determined before and after 6 wk storage at ambient temperature. Sensory characteristics were evaluated after storage and rehydration of okra slices. Blanching in boiling water with or without 0.1% SO₂ resulted in protection of the characteristic flavor of okra. Blanching in SO₂ solution before dehydration produced greater ascorbic acid retention (p < 0.05) but a substantial loss of thiamine (p ≤ 0.05).     

RHEOLOGICAL MODELING of POTATO FLOUR DURING EXTRUSION COOKING

A generalized model for predicting the effects of shear rate, temperature, moisture content, time-temperature history and strain history on viscosity has been evaluated for extruded potato flour doughs. an Instron Capillary Rheometer and a 50 mm Baker Perkins co-rotating twin screw extruder were used to evaluate all effects incorporated in the model, except strain history. the power law model was used to describe shear rate effects in the range 10–10000 s^?1. the generalized model fit observed data for temperatures of 25–95°C and moisture contents ranging from 22 to 50%, wet basis. Since potato flour by its manufacturing process is pregelatinized, it was unnecessary to evaluate the effects of time-temperature history. Strain history was found to have an insignificant influence on the viscosity.     

Chemical and Instrumental Analyses of Warmed-Over Flavor in Beef

Raw, freshly cooked, stored and recooked beef muscle samples were assessed by chemical, instrumental and sensory methods of analyses for flavor quality, with particular emphasis on warmed-over flavor (WOF). The character notes used by a trained sensory panel to describe WOF were cardboardy, rancid, stale, and metallic. Samples analyzed by direct gas chromatography utilizing either packed or fused silica capillary columns showed that compounds usually associated with lipid oxidation reactions could be used as marker compounds to follow the development of WOF. Of the many compounds that appeared to be markers, hexanal and 2,3-octanedione as well as total volatiles showed a highly significant degree of correlation when compared to sensory scores and 2-thiobar bituric acid (TBA) numbers. Many of the volatile compounds that were identified in WOF meat samples were also found in the distillates prepared for the TBA reaction.     

CALIBRATION OF THE PEA TENDEROMETER AND A COMPARISON OF TENDEROMETER READINGS FROM THREE COUNTRIES

The validity of the Texture Test System (TTS) as a reference calibration instrument for the Pea Tenderometers has been evaluated. The factors influencing the results are discussed. A linear correlation between TTS values and tenderometer units has been obtained with a correlation coefficient of at least 0.98. Calibration of the Pea Tenderometers by means of the TTS is now the standard procedure in Sweden. A comparison has been made between Swedish, English and American tenderometer readings. The results show that Swedish and English tenderometer readings are quite similar, whereas the U.S. values differ by up to 9 TU depending on the sample tenderness.