On the mid-Atlantic Coastal Plain of the United States, Paleocene sands and silts are replaced during the Paleocene-Eocene Thermal Maximum (PETM) by the kaolinite-rich Marlboro Clay. The clay preserves abundant magnetite produced by magnetotactic bacteria and novel, presumptively eukaryotic, iron-biomineralizing microorganisms. Using ferromagnetic resonance spectroscopy and electron microscopy,...

Tapioca starch, poly(lactic acid) and Cloisite 30B nanocomposites foams, with clay contents of 1, 3, 5 and 7% (w/w), were prepared by a meltintercalation method. Multiple inputs single output models were developed to predict radial expansion ratio, unit density, bulk compressibility and spring index of the nanocomposite foams. An individual ANFIS model was developed for each mechanical property...

Understanding the pore networks of unconventional tight reservoirs such as tight sandstones and shales is crucial for extracting oil/gas from such reservoirs. Mercury injection capillary pressure (MICP) and N2 gas adsorption (N2GA) are performed to evaluate pore structure of Chang-7 tight sandstone. Thin section observation, scanning electron microscope, grain size analysis, mineral composition...

Although clay mineral reduction is thought to occur primarily as a result of the activity of indigenous microorganisms in soil, most research has focused on chemical mechanisms of Fe reduction within clay minerals. Here we show that bacteria isolated from soils and sediments catalyze the rapid reduction of structural Fe(III) in the smectite clay minerals. The extent of Fe(III) reduction is larg...

The interaction of sulfonamide antimicrobial agents with smectite clay minerals and humic acid (HA)-clay complexes was investigated in batch experiments to assess the influence of adsorbed humic acid on sulfonamide sorption. Soil HA-clay complexes were produced at HA:clay ratios of 1:5, 1:50, and 1:100 (w/w). Vibrational and electronic spectroscopy indicated the preferential adsorption of polar...

Laboratory soil column experiments were conducted to study the distribution of preferential flow paths resulting from removal of fine-size clay particles. These experiments specifically studied the influence of clay (kaolinite) percentage in sand-clay mixtures and the effect of hydraulic gradients on pore evolution. Analysis of the effluent during the experiments indicated that clay particles w...

A research program was conducted on different clay-bearing rocks selected from the Ilam, Sarpol-e Zahab and Tajarak regions (Iran) to predict their slaking characteristics. The new durability apparatus (nested mesh drums) separates disintegrated particles varying from > 25.4 to < 2 mm as the drums were rotated. On the basis of the particle size distribution, the disintegration ratio (DR) was us...

the present paper investigates the influence of stabilization with cement, peat ash, and silica sand on permeability coefficient (kv) of compacted clay, using a novel approach to stabilize the clay with peat ash as a supplementary material of cement in the compacted and stabilized soil. in order to assess the mentioned influence, test specimens of both untreated and stabilized soil have been te...

The present paper investigates the influence of stabilization with cement, peat ash, and silica sand on permeability coefficient (kv) of compacted clay, using a novel approach to stabilize the clay with peat ash as a supplementary material of cement in the compacted and stabilized soil. In order to assess the mentioned influence, test specimens of both untreated and stabilized soil have been te...

I derive a production-based asset pricing formula to infer aggregate stock market returns from macroeconomic time series when the technology is putty-clay. Capital heterogeneity leads to variation in the aggregate stock market value through a new compositional e¤ect. The asset pricing formula, which holds regardless of the stochastic discount factor, predicts that the stock market value is high...