Comparison of Various Commercial Hydrated Limes for Reducing Soil Plasticity, HR-82 and HR-106, 1964

Atterberg limits tests were performed on mixtures of gumbotil soil and the various chief chemical compounds found in hydrated limes. The results were then checked with commercial hydrated limes of varying chemical compositions. Results indicate that among the major constituents of hydrated limes Ca(OH)2 is most effective in reducing soil plasticity. MgO shows a moderate effect, but Mg(OH)2 and CaCO3 show practically no effect. There is, however, practically no difference between different types or between the same type of commercial hydrated limes for the reduction of soil plasticity. The choice of lime for soil-lime stabilization should, therefore, be dictated by the relative price and pozzolanic strength characteristics of the lime.

Clay Mineralogy of a Gumbotil, HR-106, 1964

Investigation of the clay minerals in a gumbotil associated with the Mahaska soil series in Keokuk County, Iowa, indicates that the principal clay mineral is a dioctahedral calcium montmorillonite. Other clay minerals present in this gumbotil are kaolinite and mica, although they are in much smaller percentages. The investigation also pointed out difficulties involved in analyzing this type of soil by standard X-ray procedures and the complications introduced in the analysis of soil samples with high iron content utilizing standard accepted diffraction techniques.

Modification of Ca-Montmorillonite by Low-Temperature Heat Treatment, HR-106, 1964

Objectives of this investigation were to measure the effects of moderate heat treatments (below the dehydroxylation temperature) on physical and chemical properties of a calcium-montmorillonite clay. Previous workers have noted the reduction in cation exchange capacity and swelling property after heating in the range 200 to 400°C, and have suggested several possible explanations, such as hysteresis effect, increased inter-layer attractions due to removal of inter-layer water, or changes in the disposition of inter-layer or layer surface ions. The liquid limits of Ca-montmorillonite were steadily decreased with increased temperature of treatment, levelling at about 450°C. The plastic limit decreased slightly up to 350°C, above which samples could no longer be rolled into threads. The gradual change is in contrast with sudden major changes noted for weight loss (maximum rates of change at l00°C and 500°C), glycol retention surface area (520°C), and d001 diffraction peak intensity (17.7 A spacing) and breadth after glycolation (530°C). Other properties showing more gradual reductions with heat treatment were amount of exchangeable calcium (without water soaking), cation exchange capacity by NH4AC method, and d001 intensity (21 A spacing) after storing at 100% r.h. one month and re-wetting with water. Previous water soaking allowed much greater release of fixed Ca++ up to 450°C. Similar results were obtained with cation exchange capacities when samples were treated with N CaCl2 solution. The 21.0 A peak intensity curve showed close similarity to the liquid limit and plastic index curves in the low temperature range, and an explanation is suggested.

Factors Influencing Stability of Granular Base Course Mixes, Progress Report, HR-99, 1964 (April)

The problems of laboratory compaction procedures, the effect of gradation and mineralogy on shearing strength, and effect of stabilizing agents on shearing strength of granular base course mixes are discussed. For the materials tested, a suitable laboratory compaction procedure was developed which involves the use of a vibratory table to prepare triaxial test specimens. A computer program has been developed to facilitate the analysis of the test data of the effect of gradation and mineralogy on shearing strength of soils. The effects of the following materials have been selected for evaluation as stabilizing agents’ portland cement, sodium and calcium chloride, lime organic cationic waterproofer, and asphaltic materials.

Factors Influencing Stability of Granular Base Course Mixes, Progress Report, HR-99, 1964 (November)

The problems of laboratory compaction procedures, the effect of gradation and mineralogy on shearing strength, and effect of stabilizing agents on shearing strength of granular base course mixes are discussed. For the materials tested, a suitable laboratory compaction procedure was developed which involves the use of a vibratory table to prepare triaxial test specimens. A computer program has been developed to facilitate the analysis of the test data of the effect of gradation and mineralogy on shearing strength of soils. The effects of the following materials have been selected for evaluation as stabilizing agents’ portland cement, sodium and calcium chloride, lime organic cationic waterproofer, and asphaltic materials.

Books, publications, project completion reports, M.S. and Ph. D. theses : research supported by Iowa State Water Resources Research Institute under the Water Resources Research Act of 1964, U.S. Public Law 88-379, U.S. Department of the Interior, Office of Water Resources Research, 1970

This book, published jointly by the American Society of Agronomy, Soil Science Society of American and Iowa State University presents the papers that were given at a symposium held in Ames, Iowa, on Nov. 30 and Dec. 1, 1965 on the general topic of plant environment and efficient water use.

Cultura y negocios: el americanismo catalán de la Revista Comercial Ibero-Americana MERCURIO, 1901-1938.

ESTE LIBRO describe la historia de la Revista Comercial Ibero- Americana MERCURIO, la publicación barcelonesa que salió a la luz en diciembre de 1901, poco después de la pérdida de las últimas colonias (Cuba, Puerto Rico y Filipinas),y que dejó de aparecer a mediados del año 1938, en plena Guerra Civil española. Elfundador de esta revista fue José Puigdollers Macià, un importante empresario quetambién se hizo cargo del Crédito Ibero-Americano desde finales del siglo XIX. Durante los primeros años de edición, la revista se identificó por su carácter mensual, pero desde 1907 comenzó a aparecer semanalmente al dividirse entre la Edición Ilustrada y la Edición Comercial y de Transportes. La Edición Ilustrada fue posible gracias a los directores Federico Rahola Trèmols, Mariano Viada Lluch y Rafael Vehils Grau-Bolívar,y al director artístico Pere Casas Abarca. La Edición Comercial y de Transportes, por su parte, quedó en manos de los directores Simeón Mugüerza Sanz y Mariano Viada Viada.MERCURIO divulgó importantes contribuciones de más de 800 autores y autoras quecolaboraron con la revista. La encargada de resguardar las fuentes bibliográficas y hemerográficas fue María del Carmen Vehils Grau-Bolívar. El libro incluye el índice de los artículos publicados por MERCURIO entre 1901 y 1938.

Censura e Inquisición en las crónicas de Indias. De sus adversidades e infortunios

Desde su aparición hasta nuestros días, las crónicas de Indias han sufrido uncamino de infortunios. Entre los hechos que han contribuido a su escasa difusión,la falta de lectores o el poco reconocimiento, podemos destacar, en losprimeros siglos, la existencia del Tribunal Inquisitorial, las interferencias estatales en materia de Indias, la propia complejidad de las obras, las modas literarias, la rigidez de algún cura bien avenido con el poder, el temor a las copias y apropiaciones ilegales o las envidias y recelos entre los cronistas, ya fueran éstos laicos o religiosos (inquinas entre las órdenes). Asimismo, también las órdenes religiosas censuraban los documentos o textos de sus propios religiosos, cuando no encarcelaban a aquellos que sin su consentimiento habíanhecho públicas determinadas opiniones. Tal es el caso de «Motolinía», encarceladopor su propia orden, por haber escrito una Carta dirigida al emperador Carlos V contra Bartolomé de las Casas, sin previa autorización de sussuperiores...

[Rome. Tomba di Cecilia Metella]

Référence bibliographique : Weigert, 609

[Rome. Tomba di Cecilia Metella]

Référence bibliographique : Weigert, 610