Use of 2-dimensional arrays to determine the uniformity ofJosephson junctions

The linewidths of phase-locked, oscillating arrays of high temperature superconducting Josephson junctions have been used to estimate such statistical information for several junction processes using a fitting process to simulate results. Statistical data from arrays consisting of several hundred to many thousand junctions operating, and at least partially phase locked, at 77K are being used to characterize and improve junction processes. Spreads on critical currents for three different processes; step edge, edge SNS and electron-beam defined nanobridges, have ranged from ±3% to 15% (lσ) and on normal state resistances from ±2% to 11%     

Fluorometric studies of recovery metabolism of rat fast- and slow-twitch muscles

Recovery metabolism of fast-twitch extensor digitorum longus (EDL) and slow-twitch soleus (SOL) muscles of the rat has been investigated using fluorometric monitoring of reduction of nicotinamide adenine dinucleotide (NAD). In both EDL and SOL, groups of twitch contractions produced a decrease in fluorescence (oxidation of NADH) which returned to the resting base line after contraction ceased. These responses proceeded more quickly in EDL than SOL and were abolished by anoxia. A 1-s tetanus of SOL produced an initial reduction which could be abolished with iodoacetate followed by a prolonged oxidation which could be blocked by anoxia. The fluorescence of EDL was decreased immediately following a 1-s tetanus but then rapidly increased well beyond the resting level of reduction and persisted throughout the recovery period. This reduction was largely depressed by iodoacetate. The results indicate marked differences in the recovery metabolism of these muscles, consistent with predominantly mitochondrial oxidative activity in the slow-twitch muscles and predominantly glycolytic activity in the fast-twitch muscles.     

Nine years of research and development on advanced water electrolysis. A review of the research programme of the Commission of the European Communities

The development of advanced water electrolysis was one of the main tasks of the R & D programme on hydrogen funded, within its main R & D programme on Energy, by the Commission of the European Communities. Most of the work has been concentrated on the development of alkaline water electrolysis, as this process appears particularly promising. (Water electrolysis based on ‘acidic’ solid polymer electrolytes, developed during the last 10 years, seems to be a potentially attractive alternative technology, at least for electrolysers of smaller scale (up to 100kW). Even at this size, however, there is not yet evidence of any overall economic advantage over advanced alkaline cells.) The results of 9 years of R & D in this field are critically examined, by reviewing the improvements achieved on the components of the electrolytic cell as well as the overall modification of the cell design. The anode, cathode and diaphragm have been the components investigated, but also the constituent materials, the nature of the electrolyte and its operating conditions have been dealt with. Three main lines of advanced electrolyser development were identified in the course of these investigations. The corresponding charcteristics are:

1. low temperature (70°C to 90°C), low current density (i=0.1–0.3 A cm^?2);
2. moderate temperature (<120°C), high current density (i up to 1 A cm^?2), medium pressure (5–10 bars);
3. medium temperature (120–160°C), high current density (i=1–2 A cm^?2), moderately high pressure (30 bars).

In cell design, very compact cell units have been devised, in which a ‘zero gap’ configuration (anode and cathode are placed directly on the diaphragm) is generally adopted, resulting in very low internal cell resistance (about 0.2 Ω cm²). Potential energy savings of 20 to 30% can be anticipated for the advanced electrolysis. In addition to this work on advanced alkaline water electrolysis, some limited research efforts on high temperature (>1100 K) water vapour electrolysis have been made and are reported. The latter work has been concentrated on the production of thin-layer doped zirconia solid electrolytes (d=50μm), potentially leading to high performance cells. The economic implications of high-temperature vapour electrolysis, however, cannot be judged at the present status of development.     

A study of fine particulate emissions from combustion of treated pulverized municipal sewage sludge

Municipal sewage sludge (MSS) is formed during wastewater treatment and its processing and disposal represent one of the most environmentally challenging aspects of the wastewater treating process. One disposal option currently being considered is a process involving heat treatment (to render the sludge biologically inactive) followed by dewatering, drying, pulverizing, and combustion. This research focuses on fine particle emissions from the combustion of dried, treated, MSS, cofired with either natural gas or pulverized Ohio bituminous coal as a supplemental fuel. These fuels were burned at 13 kW in a downflow laboratory combustor designed to replicate time/temperature histories and particle concentrations typical of practical combustion units yet also sufficiently well defined aerodynamically to allow elucidation of mechanisms. Size-segregated particle size distributions were obtained by isokinetic sampling followed by dilution/quenching and passage into a Berner Low-Pressure Impactor. Major and trace elements were analyzed by flame and graphite furnace atomic absorption spectroscopy. Four particle size regions were identified: furnace vapor-phase material that formed ultrafine particles either in or just before the sampling probe, submicron-sized particles formed during the combustion process, micron-sized fine particles, and larger supermicron sized bulk fly ash particles. The fuel mix appears to influence trace metal partitioning routes and the composition of fine particulate matter in the exhaust. Cofiring of MSS with coal increases the ultrafine/submicron particle emission compared to firing coal alone. This increase in ultrafine/submicron particles is most likely due to an interaction between species derived from MSS (possibly alkali metals) and those from coal (possibly sulfur and/or chlorine). Vapor-to-solid phase partitioning of arsenic and selenium is controlled by surface reaction with active surface sites during MSS combustion with either gas or coal. Co-combustion of MSS with the Ohio bituminous coal allows the arsenic and selenium to be reactively scavenged by calcium, thus changing the speciation of the trace metal emitted. Ohio bituminous coal alone contained insufficient calcium to accomplish this same scavenging effect.     

Identification of isomers of nitrotoluene via free electron attachment

Free electron attachment to the three different isomers of mononitrotoluene molecules in the gas phase is studied using a crossed electron-molecule beams technique. In contrast to previous studies for a large number of negative ions, the presently measured relative cross section curves are recorded with an electron energy resolution of better than 100 meV. For several product anions including the nitro anion NO(2)-, remarkable differences for the three isomers are observed. In almost all fragment anion efficiency curves, the 2-nitrotoluene exhibits pronounced differences from the two other isomers. In contrast, 3- and 4-nitrotoluene disagree only slightly in a few fragment anions from each other.