Physical, chemical, and mineralogical properties of Mexico City sediments: a geotechnical perspective: Reply

2000 ◽  
Vol 37 (1) ◽  
pp. 276
Author(s):  
JA Díaz-Rodríguez ◽  
R Lozano-Santa Cruz ◽  
VM Dávila-Alcocer ◽  
E Vallejo ◽  
P Girón
Keyword(s):  
Mexico City ◽  
Physical Chemical ◽  
Mineralogical Properties

Physical, chemical, and mineralogical properties of Mexico City sediments: a geotechnical perspective

1998 ◽  
Vol 35 (4) ◽  
pp. 600-610 ◽  
Author(s):  
JA Díaz-Rodríguez ◽  
R Lozano-Santa Cruz ◽  
VM Dávila-Alcocer ◽  
E Vallejo ◽  
P Girón
Keyword(s):  
Mexico City ◽  
Lacustrine Sediments ◽  
Chemical Properties ◽  
Structural Features ◽  
Exchange Capacity ◽  
In Situ Tests ◽  
Physical Chemical ◽  
Mineralogical Properties ◽  
Ramon Lopez Velarde ◽  
Seismic Tests

Geotechnical, physical, chemical, and mineralogical properties of the sediments of Ramón López Velarde Park were examined. The site is located in the ancient lacustrine zone of Mexico City. In situ tests included a resistivity survey, soundings with an electric cone, and cross-hole seismic tests. In addition, a continuous core was obtained for the upper 40 m. This core was extensively studied in the laboratory to determine the variation of mineralogy, pH, organic matter, cation exchange capacity (CEC), and structural features with depth. The information is unique with respect to previous studies which focused on specimens at a single depth. Results facilitate the interpretation of the deposit evolution, leading to the current properties of this unique lacustrine sequence.Key words: Mexico City, geotechnical properties, lacustrine sediments, physical properties, mineralogy, chemical properties.

scholarly journals Relationship between soil oxidizable carbon and physical, chemical and mineralogical properties of umbric ferralsols

2011 ◽  
Vol 35 (1) ◽  
pp. 25-40 ◽  
Author(s):  
Flávio Adriano Marques ◽  
Márcia Regina Calegari ◽  
Pablo Vidal-Torrado ◽  
Peter Buurman
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Clay Content ◽  
Selective Extraction ◽  
Total Carbon ◽  
Soil Matrix ◽  
Soil Variables ◽  
Physical Chemical ◽  
Mineralogical Properties ◽  
Extractable Al

The occurrence of Umbric Ferralsols with thick umbric epipedons (> 100 cm thickness) in humid Tropical and Subtropical areas is a paradox since the processes of organic matter decomposition in these environments are very efficient. Nevertheless, this soil type has been reported in areas in the Southeast and South of Brazil, and at some places in the Northeast. Aspects of the genesis and paleoenvironmental significance of these Ferralsols still need a better understanding. The processes that made the umbric horizons so thick and dark and contributed to the preservation of organic carbon (OC) at considerable depths in these soils are of special interest. In this study, eight Ferralsols with a thick umbric horizon (UF) under different vegetation types were sampled (tropical rain forest, tropical seasonal forest and savanna woodland) and their macromorphological, physical, chemical and mineralogical properties studied to detect soil characteristics that could explain the preservation of high carbon amounts at considerable depths. The studied UF are clayey to very clayey, strongly acidic, dystrophic, and Al-saturated and charcoal fragments are often scattered in the soil matrix. Kaolinites are the main clay minerals in the A and B horizons, followed by abundant gibbsite and hydroxyl-interlayered vermiculite. The latter was only found in UFs derived from basalt rock in the South of the country. Total carbon (TC) ranged from 5 to 101 g kg-1 in the umbric epipedon. Dichromate-oxidizable organic carbon represented nearly 75 % of TC in the thick A horizons, while non-oxidizable C, which includes recalcitrant C (e.g., charcoal), contributed to the remaining 25 % of TC. Carbon contents were not related to most of the inorganic soil variables studied, except for oxalate-extractable Al, which individually explained 69 % (P < 0.001) of the variability of TC in the umbric epipedon. Clay content was not suited as predictor of TC or of the other studied C forms. Bulk density, exchangeable Al3+, Al saturation, ECEC and other parameters obtained by selective extraction were not suitable as predictors of TC and other C forms. Interactions between organic matter and poorly crystalline minerals, as indicated by oxalate-extractable Al, appear to be one of the possible organic matter protection mechanisms of these soils.

scholarly journals Development of processing technology and mathematical model of modification of magnesite raw material

2002 ◽  
Vol 50 ◽  
Author(s):  
MICHAL LESKO ◽  
TOMÁS BAKALÁR
Keyword(s):  
Mathematical Model ◽  
Mineral Processing ◽  
Processing Technology ◽  
Raw Material ◽  
Chemical Methods ◽  
Processing Methods ◽  
Physical Chemical ◽  
Mineralogical Properties

The application of physical and physical-chemical methods of magnesite processing related to the physical, chemical and mineralogical properties of particular magnesite types are presented in this paper. The best product qualities, achieved depending on the degree of liberalization of components contained in the magnesite, are shown. Possibilities and advantages of modelling of mineral processing methods applied to magnesite are also exemplified.

scholarly journals Differences and Commonalities in Physical, Chemical and Mineralogical Properties of Zanzibari Geophagic Soils

2010 ◽  
Vol 36 (1) ◽  
pp. 129-140 ◽  
Author(s):  
Sera L. Young ◽  
M. Jeffrey Wilson ◽  
Stephen Hillier ◽  
Evelyne Delbos ◽  
Said M. Ali ◽  
...  
Keyword(s):  
Physical Chemical ◽  
Mineralogical Properties

scholarly journals Physico-chemical Factors an Phytoplankton as Indicators of the Water Quality in Two Periurbans Lakes of a Natural Protected Area in Mexico City

2021 ◽  
Vol 2 (5) ◽  
pp. 60-65
Author(s):  
J. R. Latournerié-Cervera ◽  
A. R. Estrada-Ortega ◽  
A. K. Escobar-Álvarez ◽  
A. J. Quino-Trejo ◽  
R. G. Barrera-Pastrana ◽  
...  
Keyword(s):  
Water Quality ◽  
Mexico City ◽  
Fixed Effects ◽  
Statistical Design ◽  
Sampling Station ◽  
Measured Temperature ◽  
Lake System ◽  
Physical Chemical ◽  
Chemical Factors ◽  
The Impact

The protected natural area (ANP), Ejidos de Xochimilco and San Gregorio Atlapulco (SGA), is a priority area of ecological conservation in Mexico City (CDMX), that still have remnants of the ancient lake system of the Valley of Mexico watershed that have been modified for decades due to the impact of human activities and that threaten their continuity, despite been declared as a RAMSAR site and historical and cultural heritage of CDMX. Given the above, the present study aimed to compare the spatial-temporal variability of physical-chemical factors and phytoplankton as indicators of anthropogenic impact to diagnose the current state of this locality and propose possible alternatives for sustainable management in the study area. The research design considered comparing the area of channels and lagoons of the SGA wetland in two contrasting climatic seasons: dry and rainy. Eleven sampling stations were delimited: three in the channels area and eight in the lagoons, during the months of March and July. Nine physical-chemical variables were measured: temperature, pH, total solids, conductivity, dissolved oxygen, as well as the concentrations of ammonium, nitrites, nitrates, and soluble phosphorus in surface and bottom samples from each sampling station. The statistical design took into account a factorial design of fixed effects (epochs - locations and strata), with Tukey's "post hoc" test to delimit subsets and various multivariate analysis techniques. Phytoplankton samples were taken in both localities, which were identified down to the genus level, evaluating the relative frequency of the various taxa, as well as their association through the saprobity and diversity indexes. The water quality variables indicated that both the area of channels and the lagoons of the wetland are sites with hypereutrophic characteristics, but the wetland due to its semi-isolation is an area that presents on average levels of nitrates 2.4 times lower than in the channel zone, nitrite concentrations are almost imperceptible, and ammonia is within tolerable limits for the existing biota. It also presents space-time homogeneity in its physical-chemical dynamics, in contrast to the area of channels. The composition of species indicating saprobity also differed between both sites, denoting a lesser impact on the wetland area, so it is suggested to use this site for reintroduction activities of species removed from the channel area and preserve the remaining biota in the lake system.

scholarly journals Recycling of coal ash as a building material via a stabilization/solidification method

2013 ◽  
Vol 15 (4) ◽  
pp. 485-493 ◽  
Keyword(s):  
Portland Cement ◽  
Environmental Effects ◽  
Building Material ◽  
Coal Ash ◽  
Physical Chemical ◽  
Mineralogical Properties ◽  
Construction Products ◽  
Construction Product

<p>This study examines stabilization/solidification (S/S) techniques for coal ash/cement systems that involve the production of construction products while minimizing contamination and recycling the coal ash (CA). In these techniques, the polluted components of coal ash are fixed in a cement body via adsorption and confinement mechanisms, and thus, the possible impact of these pollutants on the environment is minimized. In the first step of this study, the physical, chemical, radioactive and mineralogical properties of the material used were determined. Second, coal ash (CA) was used to replace portland cement (PC) in the following proportions: 0%, 5%, 10%, 15%, 20%, 25%, 30%, 40% and 50% of PC by weight. Finally, the usability of coal ash as a construction product and the environmental effects of such usage were determined.</p>

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