MI Value Research Articles

Thermal maturity of the Barnett Shale determined from well-log analysis

Intensive development with large-scale fracturing treatments has made the Barnett Shale play (Newark East field) in the Fort Worth Basin the largest shale-gas field in the world. The Mississippian Barnett Shale is an organic-rich, self-sourced reservoir rock. Thermal maturity, thickness, and total organic carbon are the most important geological factors for commercial gas production from this shale formation. The log-derived thermal-maturity index (MI) has been developed in an effort to better understand and predict hydrocarbon phases across the basin. Maturity index was calculated using three types of open-hole logs: neutron porosity, deep resistivity, and density porosity (or bulk density). The derivation of MI is based on the hypotheses that shale gas is generated and stored locally without apparent migration from outside sources, and that the water saturation and the density of generated hydrocarbons decrease with an increase in thermal maturity. Maturity index correlates well with initial gas:oil ratios (GOR) from well production data. Based on this correlation, an empirical relationship has been demonstrated for the Fort Worth Basin. This method is useful in understanding the thermal-maturity levels of Barnett Shale source rock in the gas-generation window. Mapping MI, GOR, and gas heating value from hundreds of wells identifies the various maturity stages and areas of Barnett Shale that generate oil, condensate, wet gas, or dry gas in the Fort Worth Basin.

Giant magnetoimpedance effect in a positive magnetostrictive glass-coated amorphous microwire

The giant magnetoimpedance (GMI) effect in positive magnetostrictive glass-coated amorphous ${\mathrm{Co}}_{83.2}{\mathrm{Mn}}_{7.6}{\mathrm{Si}}_{5.8}{\mathrm{B}}_{3.3}$ microwire has been studied as a function of a dc magnetic field $\ensuremath{-}140l{H}_{\mathrm{dc}}l140\mathrm{Oe}$ and frequency $0.1lfl12.85\mathrm{MHz}.$ A maximum change of 43% in the MI of the as-quenched sample has been observed around 5 MHz frequency. Heat treatment of the sample by passing a dc current of 50 mA through it enhances the MI value to a large extent (maximum change \ensuremath{\sim}94%) by increasing the outer domain volume and inducing a transverse anisotropy. On the other hand, application of an external tensile stress reduces the GMI value by increasing the inner core domain and developing an axial anisotropy. In an as-quenched sample, the maximum value of MI is observed at ${H}_{\mathrm{dc}}\ensuremath{\sim}0$ when measured at frequency $fl8\mathrm{MHz}$ beyond which a two peak MI profile is seen. The heat-treated sample shows this two peak behavior from a much lower frequency (below 1 MHz) and additional peaks at ${H}_{\mathrm{dc}}\ensuremath{\sim}0$ for $fg10\mathrm{MHz}.$ Asymmetry in the MI peaks of a microwire has been produced by passing a dc current through the sample during impedance measurement. The magnetization of the as-quenched and heat-treated samples has also been studied to understand the domain structure and magnetoimpedance results.

Red-giant branch of the old, metal-rich open cluster NGC 6791

view Abstract Citations (83) References (50) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Red-Giant Branch of the Old, Metal-Rich Open Cluster NGC 6791 Garnavich, Peter M. ; Vandenberg, Don A. ; Zurek, David R. ; Hesser, James E. Abstract V and I photometry out to 12 min from the center of the old, populous, metal-rich, open cluster NGC 6791 has revealed 16 bright stars (I less than or equal to 12.5) with 1.6 less than or equal to V - I less than or equal to 4.1. Follow-up spectroscopy indicates that (1) at least 12 of these red-giant branch (RGB) candidates are bona fide cluster members, and (2) their metallicity, as estimated from the strength of the Ca II infrared triplet lines, is slightly above solar. If the core helium-burning (`clump') stars in NGC 6791 have a mean MV = 0.9, which is the current best estimate for that of their counterparts in the (M/H) approximately equal to 0.0 cluster M67, then the apparent distance modulus of the former is near (m - M)V approximately equal to 13.6. This would imply an age of about 9 Gyr, from appropriate stellar models, versus approximately equal to 4.5 Gyr for M67. Importantly, with this estimate of the distance -- which is unlikely to be in error by more than +/- 0.25 mag -- the color-magnitude diagram (CMD) of NGC 6791 intimates that its RGB does not rise above MI approximately -2.7. In contrast, the RGBs of all Galactic globular clusters with metallicities of one-quarter solar or less are presently believed to reach MI approximately equal to -4.0, though fainter tip magnitudes have been inferred for the very few globulars of higher metal abundance (e.g., NGC 6553) that have been studied. If the tip MI value does not vary with metallicity among (at least) the most metal-rich systems, then that variation can be expected to affect, e.g., estimates of the extragalactic distance scale based on the `surface brightness fluctuation' method. Consequently, NGC 6791 provides an exceedingly important constraint on our understanding of old, metal-rich stellar populations. Encouragingly, theoretical evolutionary tracks whose temperatures and colors are consistent with various empirical constraints appear to provide a fine match to the upper CMD of NGC 6791, if the cluster metallicity is (M/H) greater than 0.0. Publication: The Astronomical Journal Pub Date: March 1994 DOI: 10.1086/116921 Bibcode: 1994AJ....107.1097G Keywords: Astronomical Photometry; Astronomical Spectroscopy; Color-Magnitude Diagram; Images; Interstellar Extinction; Metal Clusters; Metallicity; Radial Distribution; Red Giant Stars; Velocity Distribution; Astronomical Observatories; Cassegrain Optics; Charge Coupled Devices; Gratings (Spectra); Optical Filters; Point Spread Functions; Spectrographs; Telescopes; Astrophysics; OPEN CLUSTERS AND ASSOCIATIONS: INDIVIDUAL: NGC 6791; STARS: GIANT full text sources ADS | data products SIMBAD (30)

EVOLUTIONARY AND GEOGRAPHIC TRENDS IN ADAPTIVE WOOD ANATOMY IN ERIASTRUM DENSIFOLIUM (POLEMONIACEAE)

Anatomical features of Eriastrum densifolium populations in southern California show variation that correlates well with ecological setting and geographical distribution. Vessel element size and density in shoots suggest strong adaptation among different subspecies to efficient water movement in different habitats. Indices of mesomorphy, devised by Carlquist to indicate relative adaptivity of wood, likewise show considerable variation among populations, suggesting that different subspecies have anatomical components that can define them. Relationships among the five subspecies of E. densifolium may be explored through MI value relationships.

Leucocyte migration inhibition test in diabetes mellitus (author's transl)

The leucocyte migration inhibition test (LMT) using the agarose plate method introduced by Clausen is simple and highly reproducible. Using thyroglobulin, mitochondria and thyroid microsomal fractions as antigens, LMT was performed on ten patients with insulin dependent diabetics, twenty patients with insulin independent diabetics, eleven patients with Graves' diseases, ten patients with chronic thyroiditis and ten healthy controls. The migration index was expressed as a percentage of migration and calculated from the following formula; (formula: see text). Using a thyroid microsomal fraction, the mean migration index for the insulin dependent diabetics (93.2 +/- 11.6) was significantly lower than in the normal subjects (104.3 +/- 10.9) (0.025 less than p less than 0.05). Using thyroglobulin as an antigen for the insulin dependent diabetics and insulin independent diabetics, the mean migration indices (+/-SD) were 93.7+/-10.8 and 102.8+/-10.6 respectively. The corresponding values for the control group were 100.6+/-7.3. Using a mitochondria, MI values for insulin dependent and independent diabetics were 97.7+/-5.5 and 99.6+/-12.6 respectively, while MI value for the control group was 103.9+/-13.6. The mean migration indices obtained with the mitochondria and thyroglobulin were not significantly depressed when the diabetic groups were compared with the normal subjects.

Effect of cannabis (hashish) on mitosis ofallium cepa L. root tips

Treatment with cannabis induces a partial inactivation of the spindle apparatus, and an unequal separation of the chromosomes. There is more or less a tendency to с-mitosis at higher concentrations and to multipolar anaphases at lower concentrations like so many other narcotic substances. The MI value decreases linearly and sharply with the increase of concentrations used,i.e. cannabis had a severe mitodepressive effect. Long treatment for 24 h caused the death of all colls examined. Cannabis causes a complete dissolution of the matrix substance of the chromosomes and breaks down the chromatin material of the nucleus to minute granules. This phenomenon was observed in all root tips treated with the cannabis. The same picture was observed after letting the roots recover in water. The application of cannabis may disturb the extrachromosomal mechanism. This disturbance is restricted to the abnormal diffusion of the spindle organizers in many directions instead of two poles.