183 research outputs found
On the adjustment of capacity utilisation to aggregate demand: Revisiting an old Sraffian critique to the Neo-Kaleckian model
For many years, there was an unanswered theoretical question among Post-Keynesian scholars: What's the behaviour through time of capacity utilisation after an aggregate demand shock? Under a (baseline and extended) Neo-Kaleckian framework, there should be a persistent effect on capacity utilisation to a shock like this one. On the other hand, Classical-Keynesian scholars are inclined to emphasise a continuous tendency towards normal utilisation. I tried to shed some light on this issue by adopting a Panel Structural VAR, time series SVAR and Local Projections. My findings, based on national quarterly data for 34 countries, suggest that the nature of the effects on effective capacity utilisation of shocks to the level of economic activity is merely transitory
Cycling Performance of the Iron-Chromium Redox Energy Storage System
Extended charge-discharge cycling of this electrochemical storage system at 65 C was performed on 14.5 sq cm single cells and a four cell, 867 sq cm bipolar stack. Both the anolyte and catholyte reactant fluids contained 1 molar concentrations of iron and chromium chlorides in hydrochloric acid and were separated by a low-selectivity, cation-exchange membrane. The effect of cycling on the chromium electrode and the cation-exchange membrane was determined. Bismuth and bismuth-lead catalyzed chromium electrodes and a radiation-grafted polyethylene membrane were evaluated by cycling between 5 and 85 percent state-of-charge at 80 mA/sq cm and by periodic charge-discharge polarization measurements to 140 mA/sq cm. Gradual performance losses were observed during cycling but were recoverable by completely discharging the system. Good scale-up to the 867 sq cm stack was achieved. The only difference appeared to be an unexplained resistive-type loss which resulted in a 75 percent W-hr efficiency (at 80 mA/sq cm versus 81 percent for the 14.5 sq cm cell). A new rebalance cell was developed to maintain reactant ionic balance. The cell successfully reduced ferric ions in the iron reactant stream to ferrous ions while chloride ions were oxidized to chlorine gas
Single cell performance studies on the Fe/Cr Redox Energy Storage System using mixed reactant solutions at elevated temperature
Experimental studies in a 14.5 sq cm single cell system using mixed reactant solutions at 65 C are described. Systems were tested under isothermal conditions i.e., reactants and the cell were at the same temperature. Charging and discharging performance were evaluted by measuring watt-hour and coulombic efficiencies, voltage-current relationships, hydrogen evolution and membrane resistivity. Watt-hour efficiencies ranged from 86% at 43 ma/sq cm to 75% at 129 ma/sq cm with corresponding coulombic efficiencies of 92% and 97%, respectively. Hydrogen evolution was less than 1% of the charge coulombic capacity during charge-discharge cycling. Bismuth and bismuth-lead catalyzed chromium electrodes maintained reversible performance and low hydrogen evolution under normal and adverse cycling conditions. Reblending of the anode and cathode solutions was successfully demonstrated to compensate for osmotic volume changes. Improved performance was obtained with mixed reactant systems in comparison to the unmixed reactant systems
Preparation and characterization of electrodes for the NASA Redox storage system
Electrodes for the Redox energy storage system based on iron and chromium chloride reactants is discussed. The physical properties of several lots of felt were determined. Procedures were developed for evaluating electrode performance in lab scale cells. Experimental procedures for evaluating electrodes by cyclic voltammetry are described which minimize the IR losses due to the high internal resistance in the felt (distributed resistance). Methods to prepare electrodes which reduced the coevolution of hydrogen at the chromium electrode and eleminate the drop in voltage on discharge occasionally seen with previous electrodes were discussed. Single cells of 0.3329 ft area with improved membranes and electrodes are operating at over 80% voltage efficiency and coulombic efficiencies of over 98% at current densities of 16 to 20 amp % ft
On the empirical content of the convergence debate: Cross-country evidence on growth and capacity utilisation
The Neo-Kaleckian model predicts that actual capacity utilisation is endogenous to demand shocks and positively correlated with growth in the short and long run. Competing macroeconomic theories predict that such correlation does not exist in the long run and demand shocks have transitory effects on capacity utilisation. Using a quarterly unbalanced panel of 21 developed and developing countries, we show that taking into account direct survey measures, capacity utilisation is stationary, positively correlated with growth in the short run and uncorrelated with growth in the long run. These results are inconsistent with the long-run behaviour of the Neo-Kaleckian model
Oil Nationalism as a Deterrent to Structural Change? The Case of Oil Contracts in Argentina (1958-1962)
Due to growing oil imports, political leaders had been forced to let private compa- nies produce the much-needed oil without which modern life is impossible. The most strident political clashes with what is known as ‘oil nationalism’, both ending in a coup d’ ́etat, happened in the period 1954/55 and 1958/63. The former had President Per ́on’s dealings with the California Argentina de Petro ́leos S.A., a subsidiary of the Standard Oil, at the center of a heated debate and, the latter, had President Frondizi’s oil contracts with foreign oil companies. The historical, political and diplomatic back- ground is developed so as to understand the complexities that led to the annulment of this unprecedented and effective policy with impressive effects on oil production and investment. For the first time, we show empirical evidence on the effectiveness of these contracts on domestic oil production
Apparatus enables accurate determination of alkali oxides in alkali metals
Evacuated apparatus determines the alkali oxide content of an alkali metal by separating the metal from the oxide by amalgamation with mercury. The apparatus prevents oxygen and moisture from inadvertently entering the system during the sampling and analytical procedure
Analytical and experimental studies of acoustic performance of segmented liners in a compressor inlet
The performance of axially segmented (phased) acoustic treatment liners in the inlet of a compressor was investigated. Topics discussed include: (1) the validation of a theoretical procedure to predict propagation and suppression characteristics of duct liners; (2) the in-duct measurement of spinning modes; (3) investigation of phased treatment designs; (4) high Mach inlet acoustic tests; and (5) an experimental investigation of inlet turbulence. The analytical prediction for the multi-segmented treatment was found to provide the correct order of magnitude of suppression and was generally within 50% of that determined experimentally. Refinements required to improve the correlation are identified. Suppression due to high subsonic Mach number flow effects was found to become significant above an average throat Mach number of 0.65 to 0.7 and 20 PNdB was achieved with an average throat Mach number in the range of 0.80 to 0.85. For the measured turbulence in the inlet, including the axial and circumferential turbulence intensities and the axial integral length scale, data are presented with and without an inlet screen showing that the screen reduced the turbulence intensities and that the BPF noise was reduced as a consequence
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Abstract Thirty-four patients with acute hemispheric ischemic strokes underwent both CT angiography and contrastenhanced transcranial color-coded duplexsonography (TCCD) to study the effectiveness of the combined noninvasive techniques for evaluation of the circle of Willis. In 3/34 patients, CT angiography and contrast-enhanced TCCD demonstrated middle cerebral artery (MCA) occlusion, in 5 others MCA stenosis. A severe posterior cerebral artery stenosis was missed by CT angiography. In 8 patients, contrast-enhanced TCCD failed because of poor bone windows. In these patients, CT angiography was normal. CT angiography and contrast-enhanced TCCD are complementary noninvasive diagnostic tools. Disagreements between the diagnostic findings of these methods still need further evaluation by digital subtraction angiography
Generation of MeV electrons and positrons with femtosecond pulses from a table-top laser system
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