&bstracL Planar impact experiments were employed to induce dynamic tensile failure in Bedford limestone. Rock discs were impacted with aluminum and polymethyl methacralate (PMMA) flyer plates at velocities of 10 to 25 m/s. Tensile stress magnitudes and duration were chosen so as to induce a range of microcrack growth insufficient to cause complete spalling of the samples. Ultrasonic Pand S-wave...

Petroleum resources are found within sedimentary rocks that have a sufficient interconnected void space to store and transmit fluids. The actual flow of liquid and gas phases occurs on a micrometer scale in the void space between rock grains. On the other hand, the hydrocarbon is typically carried in rock zones that are a few tens of meters thick but extend several kilometers in the lateral dir...

This paper presents measurement and analysis of the dynamic response of a five-story building to very-high frequency excitation (> 100 Hz) from blasting vibrations originating from a contiguous excavation of rock. Velocity response measurements, in the rock and on the structure, were employed to calculate time correlated dynamic displacement response of the building to blasting. Time correlated...

a r t i c l e i n f o The purpose of this study is to analytically predict and to experimentally investigate the seismic response of adjacent filled parallel rock fractures with dissimilar properties (e.g., fracture thickness and stiffness). The time-domain recursive method is extended to predict that a P-wave propagates normally across the filled parallel fractures using the specific stiffness...

The mechanical properties of any substance are essential facts to understand its behaviour and make the maximum use of the particular substance. Rocks are indeed an important substance, as they are of significant use in the energy industry, specifically for fossil fuels and geothermal energy. Attenuation of seismic waves is a non-destructive technique to investigate mechanical properties of res...

Small samples of rock, like those used in laboratory collision experiments, are known to be much stronger than bodies that are meters to hundreds of meters in size [1]. Specifically, the impactor energy per unit target mass needed to shatter the target decreases dramatically with increasing target size. This occurs because the strength of rock, like many other geological materials, depends stro...

I will start this treatise with a history of two major themes in data integration. In my opinion, the topic began with the major retailers in the 1990s consolidating their sales data into a data warehouse. To do this they needed to extract data from in-store sales systems, transform it into a predefined common representation (think of this as a global schema), and then load it into a data wareh...

In order to automate the scooping task, it is desirable that the resistive force acting on the bucket be obtained before the scooping is performed. The objective of this study is to derive theoretically the resistive forces acting on the bucket during scooping of piled rock fragments. First, the changes in the shape of the rock pile due to the penetration of it by the bucket are modeled. Based ...

background: fusobacterium necrophorum as a non-spore-forming gram-negative anaerobic bacillus is an important human and animal pathogen. it may cause severe systemic infections (lemierre's syndrome) and some other infections. the aim of this study was to subtype fusobacterium necrophorum by using pcr methods. materials and methods: twenty five strains of fusobacterium necrophorum subspecies fun...