As pointed out in the introduction to this book, shales contain the lion’s share of earth history that is recorded in sedimentary rocks. Understanding their deposition is key to the reconstruction of past oceans, landscapes, climates, and climatic cycles. Yet, whereas students of sandstones and carbonates have been able to learn a great deal about the deposition of these rocks from studying bed...

in this study, principal components analysis was used to investigate lithological characteristics of jahani salt dome, firouzabad. the spectral curves of rocks in the study area show that the evaporate rocks have the highest reflectance at specified wavelengths. the highest reflection has been seen in gypsum and white salt, while minimal reflection can be observed in the igneous rocks from the ...

nezam-abad area is located in southwest of shazand (arak) which is a part of sanandaj-sirjan zone. major intrusive rocks of nezam-abad are quartz diorite and minor amount of granodiorite. leucogranitic, pegmatite dykes and quartz-tourmaline veins were intruded the quartz diorite. quartz diorites are mainly composed of plagioclase, hornblende, biotite, quartz and pyroxene as major minerals. majo...

objectives: the purpose of this study was to evaluate the resistance to fatigue failure of five different nickel-titanium rotary files in three different curved trajectories. materials and methods: a total of 150 neoniti a1, race 25.06, mtwo 25.06, twisted file 25.06 and protaper next x2 files with the tip size of 25 were tested (n=30 for each group). three groove types simulating curved canals...

many procedures suggest for reduction of responses of riser to vortex induced vibrations (viv). natural frequencies of marine risers is an important parameter that can affect the responses of riser to viv. change of riser properties such as top tension and bending stiffness can alter natural frequencies. in this study effects of riser specifications on the responses and fatigue damage of marine...