The Pattern of the Mineralization of Enamel

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68291/2/10.1177_00220345610400050101.pd

Testing reproducibility of vitrinite and solid bitumen reflectance measurements in North American unconventional source-rock reservoir petroleum systems

An interlaboratory study (ILS) was conducted to test reproducibility of vitrinite and solid bitumen reflectance measurements in six mudrock samples from United States unconventional source-rock reservoir petroleum systems. Samples selected from the Marcellus, Haynesville, Eagle Ford, Barnett, Bakken and Woodford are representative of resource plays currently under exploitation in North America. All samples are from marine depositional environments, are thermally mature (T >445 °C) and have moderate to high organic matter content (2.9–11.6 wt% TOC). Their organic matter is dominated by solid bitumen, which contains intraparticle nano-porosity. Visual evaluation of organic nano-porosity (pore sizes 1.0 produced lowest R values, generally ≤0.5% (absolute reflectance), similar to a prior ILS for similar samples. Other traditional approaches to outlier removal (outside mean ± 1.5*interquartile range and outside F10 to F90 percentile range) also produced similar R values. Standard deviation values < 0.15*(VR or BR) reduce R and should be a requirement of dispersed organic matter reflectance analysis. After outlier removal, R values were 0.1%–0.2% for peak oil thermal maturity, about 0.3% for wet gas/condensate maturity and 0.4%–0.5% for dry gas maturity. That is, these R values represent the uncertainty (in absolute reflectance) that users of vitrinite and solid bitumen reflectance data should assign to any one individual reported mean reflectance value from a similar thermal maturity mudrock sample. R values of this magnitude indicate a need for further standardization of reflectance measurement of dispersed organic matter. Furthermore, these R values quantify realistic interlaboratory measurement dispersion for a difficult but critically important analytical technique necessary for thermal maturity determination in the source-rock reservoirs of unconventional petroleum systems.This research was funded by the USGS Energy Resources Program

Antennas

The basic purpose of a global navigation satellite system (GNSS) user antenna is the reception of navigation signals from all visible GNSS satellites. Transmit antennas onboard the GNSS satellites, on the other hand, are quite different and employ large antenna arrays to create high-gain global beams illuminating the entire surface of the Earth. This chapter presents different design options for GNSS antennas operating in the L-band of the radio frequency spectrum. It starts with a brief discussion of key requirements for the GNSS receiving antenna, where several design parameters are introduced and explained. Thereafter, antennas of different design technologies suitable to GNSS are explored and discussed in detail. Following the introduction of major antenna candidates, different variants for specialized requirements, such as the small form factor or multipath mitigation are presented. Complementary to receiving antennas, the design of antenna arrays for signal transmission on the GNSS satellites is presented next, along with a discussion on specific antennas employed on the Global Positioning System (GPS), Galileo, Global’naya Navigatsionnaya Sputnikova Sistema (GLONASS) and BeiDou satellites. Finally, a comprehensive discussion on antenna measurements and the performance evaluation is provided