A high-power carbohydrate fuel cell

This paper reports the development of a fuel cell consisting of a vanadium flow battery in which the vanadium ions are reduced by sugar (from a carbohydrate) to oxidation state +3 on one side of a membrane, and are oxidized to state +5 on the other side by oxygen. The theoretical upper limit to the conversion efficiency of the energy in sugar by this method under standard conditions is 54%. We have obtained efficiencies up to 45% in our laboratory tests. This way of using biomass for electricity production avoids the Carnot cycle losses in heat engines.     

The molecular location of Ehrlich chromogen and pyridinoline cross-links in bovine perimysial collagen

Collagenous peptides containing the Ehrlich chromogen (EC), a trifunctional cross-link of proposed pyrrolic structure, were selectively isolated from a tryptic digest of bovine perimysial collagen by coupling to a diazotised support. Peptides containing pyridinoline (Pyr), another trifunctional cross-link but based on a 3-hydroxypyridinium ring, were isolated from the uncoupled material. The isolated cross-linked peptides were purified by chromatographic procedures and subsequently characterised by amino acid and sequence analyses. EC occurred in stoichiometric amounts in three-chained peptides derived from type I collagen cross-link regions. In contrast, Pyr was found in non-stoichiometric amounts in three-chained peptides where two of the chains were identified as the 76 amino-terminal residues of the α1 (III) collagen chain. The third chain in these Pyr cross-linked peptides was derived from the C-terminal helical cross-link region of either type III collagen or the corresponding region of type I collagen, with the former region predominating. These findings suggest that EC and Pyr cross-links of perimysial collagen are associated mainly with type I and type III collagen respectively.     

The effect of cooking and processing on the glucosinolate content: Studies on four varieties of portuguese cabbage and hybrid white cabbage

The concentrations of individual and total glucosinolates were measured in four types of Portuguese cabbage and in one hybrid white cabbage before and after cooking. Typical Portuguese culinary procedures include boiling the cabbage for 10 min but for particular kale types the leaves are first shredded then boiled for 5 min (Caldo verde). Analysis of the fresh cabbage, cooked leaves and cooking water showed that the glucosinolate content of the cabbages is reduced by more than 50%. Almost all of this loss is accounted for as intact glucosinolates in the cooking water, normally used for soups in Portugal.     

Roadmapping the Technological Future of Electricity

A future-scanning collaboration orchestrated by the Electric Power Research Institute has sought to illuminate the technologies whose development will be needed to attain the “2 percent” solution of improvements in economic productivity, energy efficiency and agricultural productivity necessary for global sustainability.     

Correlation of electron and proton-irradiation-induced damage in InP solar cells

The measured degradation of epitaxial shallow homojunction n⁺p InP solar cells under 1-MeV electron irradiation is correlated with that measured under 3-MeV proton irradiation based on ‘displacement damage dose’. The measured data are analyzed as a function of displacement damage dose from which an electron-to-proton dose equivalency ratio is determined which enables the electron and proton degradation data to be described by a single degradation curve. It is discussed how this single curve can be used to predict the cell degradation under irradiation by any particle energy. The degradation curve is used to compare the radiation response of InP and GaAs/Ge cells on an absolute damage energy scale. The comparison shows InP to be inherently more resistant to displacement damage deposition than the GaAs/Ge.     

MLEK crystal growth of (100) indium phosphide

We have used a combined magnetic liquid encapsulated Kyropoulos/Czochralski (MLEK/ MLEC) technique to produce twin-free indium phosphide (InP) crystals. This technique has advantages over the standard LEC method used for commercial production of InP. By stabilizing convective flows with a magnetic field and controlling the angle between solid and liquid, one can grow large diameter twin-free (100) InP crystals; they are shaped with a flat top as is typical for Kyropoulos growth, and then pulled from the magnetically stabilized melt as in Czochralski growth. This shaping method has the benefit of maximizing the number of single crystal wafers which can be sliced from the boule. MLEK InP growth is distinguished from other methods such as LEC and MLEC with respect to solid-liquid interface shape, dislocation density, and impurity distribution. This process has demonstrated that twin-free InP (100) crystals can be consistently grown.     

An Adaptive Tourniquet for Improved Safety in Surgery

The increasingly recognized inability of the current generation of pneumatic tourniquets to control pressure with adequate accuracy, reliability, and stability has been associated with continuing reports of tourniquet-related injuries, incidents, and hazards. Moreover, the labor-intensiveness and operating costs associated with the use of current types of pneumatic tourniquets have significant cost implications for hospitals. To a large extent, the recent development of a microprocessor-based tourniquet capable of safely and accurately maintaining a desired pressure, and capable of simultaneously performing other functions such as detection of alarm conditions, has reduced these hazards and operating-cost implications. Furthermore, the availability of a microprocessor-based tourniquet has facilitated the development of the adaptive tourniquet described in this paper, in which the pressure in a tourniquet cuff is changed throughout a surgical procedure as a function of the patient's changing intraoperative systolic pressure, thus approximating the minimum safe pressure necessary to maintain a bloodless field for surgery. While the use of an adaptive tourniquet, rather than just a microprocessor-based tourniquet set at a constant pressure may not be necessary in most cases, it promises to have significant value in certain surgical procedures and for patients who may be at greater risk of tourniquet-induced complications. Also, the lower average pressures possible through the use of an adaptive tourniquet may permit the evolution of surgical techniques of longer duration without a concomitant increase in the risk of tourniquet-induced complications.     

Rayonnement de réseaux périodiques avec conducteurs et diélectrique

This paper describes a numerical analysis of the electromagnetic behaviour of dielectric panels. These dielectric panels are very large comparatively to the wave length and can be seen as infinite and plane array of dielectric cylinders, illuminated by a plane wave. These dielectric cylinders can have any cross section and can include metallic wires. The conduction currents on the metallic wire and deplacement currents in the dielectric cylinders are determinated by a system of linear equations obtained by the application of vectors potential formalism. The use of Poisson summing gives the possibility to explicite over squared or rectangular boundaries the integrals relative to the deplacement currents. The knowledge of the currents permits to calculate the transmission coefficient of the array. The comparison between the numerical results and experimental measure shows a good agreement.     

Status of aqueous surfactant phase science

Recent phase studies of several surfactant-water systems, using new or refined methods, have revealed significant errors in earlier phase diagrams. These diagrams had been determined largely using methods based on the isoplethal phase studies principle. This principle has inherent limitations which do not exist in isothermal methods. Isothermal nuclear magnetic resonance and refined calorimetric methods have been extensively used in recent surfactant phase studies. Methods based on the new lyotrope gradient (swelling) principle show great promise as a means of improving the efficiency and quality of surfactant phase studies.     

Isolation and characterization of polymers in heated olestra and an olestra/triglyceride blend

High molecular weight components in thermally oxidized olestra (formerly called sucrose polyesters) and a mixture of olestra and soybean oil were characterized. The high molecular weight components of these oils were separated by preparative size exclusion chromatography and analyzed intact by mass spectrometry, infrared, and nuclear magnetic resonance spectroscopy. The materials isolated from the heated olestra were identified as olestra polymers. Materials isolated from the heated mixed oil (olestra and soybean oil) were identified as polymers of olestra and copolymers of olestra and triglycerides. Polymer linkages identified were identical to those resulting from thermal oxidation of natural vegetable oils of similar fatty acid composition.