Small, low power analog-to-digital converter

A small, low-power, high-speed, 8-bit analog-to-digital converter using silicon chip integrated circuits is suitable for use in airborne test data systems. The successive approximation method of analog-to-digital conversion is used to generate the digital output

A Reexamination of Tax Distortions in General Equilibrium Models

General equilibrium models have recently been used to simulate the effects of many proposed tax changes. However, in modeling the effects of the government on the economy, these models have assumed for simplicity that marginal tax rates equal the observed average tax rates, and that marginal benefit rates are zero. The main purpose of this paper is to derive improved estimates of various marginal tax and benefit rates. Most importantly, we include in the model recent theories concerning the effects of combined corporate and personal taxes on corporate financial and investment decisions. The conclusions previously derived concerning the effects of corporate tax integration are then reexamined in light of the proposed changes.

Studies in Allophane in Scottish Soils

High amounts of allophane as measured by the sodium fluoride test were found in the brown forest soils and B horizons of podzols developed on basalt and basalt till. A hydrologic sequence of the Darleith association was examined and the soils' strong aggregation, high organic matter levels and phosphate retention were found due to their allophane content. Allophane was found also in the C horizons of podzols of other material. C horizons flocculated on ultra-sonic vibration but were dispersed in ammonia. All horizons however, when vigorously peroxidised, behaved like allophane soils and remained flocculated in alkaline suspension. The relative tendency of a soil to flocculate appeared to depend on the number of aluminous sites exposed ie. on the amount of allophane and its SiO2 : Al2O3 ratio. This correlation was supported by analysis of the alumino-silicate extracted with (a) cold 5% Na2CO3 (b) cation exchange resin (c) 1% citric acid, and by the rise in suspension pH on NaF treatment. NaF released more Al, and Na2CO2 more Al and much more Si when added to dry soil than to suspensions, and this was attributed to energy provided by the heat of wetting. Successful dispersion of flocs , as measured by mechanical analysis , was obtained for a New Zealand Tirau B horizon and the peroxidised Scottish soils by: (1) Vibrating in HCl at pH 4.3. This was only possible for Tirau B, with negligible clay mineral present. (2) Vibrating in zirconium or thorium nitrate solution and pH controlled at 4.3. Adsorption of the hydrolysis products (polycations) on the negative colloids, reversing their charge, was the dispersion mechanism, (3) Shaking with Na-exchange resin, followed by hand shaking in ammonia. The resin took up large quantities of alumina and silica and some iron, in addition to bases. (4) Vibrating in alkaline silica sol. (5) Vibrating in sodium hexametaphosphate. Peroxidised Darleith soil dispersed in calgon. Tirau B was partially dispersed in (NaPO3)6 at pH 7.5. (6) Repeated washing of alkaline flocs followed by shaking in NaOH (efficiency not yet measured). (7) Dialysis at soil pH gave partial dispersion of Tirau B. Alkaline flocculation of allophane could be explained in terms of (a) alumina groups (b) their capacity to adsorb hydroxyl (c) the presence of free electrolyte. Dispersion was achieved by any mechanism which interfered with one of these, viz. by:- masking alumina groups with organic matter or silica; 'destroying' hydroxyl with H+ ions; or removal of electrolyte. This interpretation is Inherent in Mattson's 1922 paper, In which adsorbed hydroxyl ions were shown to be flocculating agents, and a bridging mechanism dependent on electrostatic linkages between them and divalent cations in the free electrolyte was envisaged. A review was made of the concepts of aggregation, coagulation and flocculation. Experiments showed the validity of the distinction between 'coagulation' by electrolytes and 'flocculation' by polyelectrolytes was unsubstantiated. It was suggested that aggregation could be Interpreted in terms of the double layer Verwey-Overbeek theory, but flocculation required another explanation. Mattson's work, together with his postulate of the crucial role of the hydroxyl group should be reappraised. The unusual cation exchange properties of allophane described In the work of New Zealand and Japanese soil scientists were re-interpreted in the light of Mattson's experiments with amphoteric colloids. Anomalies were explained in terms of the acidoid-basoid complex. Sodium fluoride was used to extract allophane-held organic matter. Optimum conditions were established at pH 6 to 7. Approximately 30% of total polysaccharide was extracted, or allowing for non-humified cellulose, about 50% of soil 'combined' polysaccharide. It appeared to be representative in composition. Sodium fluoride extraction of soils high in allophane offers a technique for the systematic study of virtually unaltered organic matter. N.B. Plastic artefacts interfered with organic matter studies: (a) Moist soils stored in plastic bags became impregnated with mobile hydrocarbons. (b) Dialysis tubing dissolved out reducing substances. These gave high values to polysaccharide analyses and interfered with sugar chromatograms. The Forestry Commission finding that spruce checked on basalt brown forest soils, and that the needles showed phosphate deficiency although the soils appeared to contain adequate phosphate, led the writer to postulate that aluminium toxicity was the cause of the phosphate deficiency. Large amounts of alumina were dissolved by 1% citric acid. Mattson and Hester (1933) showed that the pH of injury to wheat seedlings was raised in soils of low silica-sesquioxide ratio due to the greater mobility of aluminium. If the toxicity hypothesis were correct, the condition could be ameliorated by adding organic matter to mask aluminous sites and lower the pH of injury, or by liming. An alternative crop might thrive better than spruce. No allophane reaction to the NaF test was found on Darleith soils under hardwood, even where it was strong in the adjoining grassland

Transfer Restrictions and Misallocation of Irrigation Water

Water is among the most abundant of all materials known to man. In all its various forms, water covers 75 percent of the earth\u27s surface. It is estimated that the total physical quantity of water on the earth is 326,000,000 cubic miles. This apparent abundance belies the true nature of the water resource as it relates to the needs of man. At any given point in time, only a rather minute portion of this vast quantity of water is found in those forms and locations which render it useful to man. This may be attributed to the fact that utility in water is perishable and the efforts of man to amend the hydrological cycle have been successful only to a limited extent

A COMPARISON OF THE ECONOMIC RENT AND CONSUMER SURPLUS METHODS OF VALUING RECREATION BOATING SITES

Resource /Energy Economics and Policy,

Cross Border Business Cycle Impacts on the El Paso Housing Market

There is comparatively little empirical evidence regarding the impacts of cross border business cycle fluctuations on metropolitan housing markets located near international boundaries. This study examines the impacts of economic conditions in Mexico on sales of existing single-family houses in El Paso, Texas. Anecdotal evidence suggests that these impacts are fairly notable. Annual frequency data from the University of Texas at El Paso Border Region Modeling Project are used to test this possibility. Results indicate that solid empirical evidence of such a linkage is elusive.Business Cycles, Border Housing Markets