methods retrospective cohort study of blunt trauma patients with rib fractures at a level i trauma center that had both a cxr and a ct chest. the ct finding of ≥ 3 additional fractures in patients with ≤ 3 rib fractures on cxr was considered clinically meaningful. student’s t-test and chi-square analysis were used for comparison. results we identified 499 patients with rib fractures: 93 (18.6%)...

Cross-borehole flowmeter tests have been proposed as an efficient method to investigate preferential flowpaths in heterogeneous aquifers, which is a major task in the characterization of fractured aquifers. Cross-borehole flowmeter tests are based on the idea that changing the pumping conditions in a given aquifer will modify the hydraulic head distribution in large-scale flowpaths, producing m...

Characterisation of fractured rocks and evaluation of fracture connectivity are essential for the study of subsurface flow and transport in fractured rock aquifers. In this study, we use a new method to present fracture networks and analyse the connectivity of the fractures, based on the technique of randomly-generated realisations. The application of the method aims to provide more detailed in...

This paper presents the results of a field investigation in the unsaturated, fractured welded tuff within the Exploratory Studies Facility (ESF) at Yucca Mountain, NV. This investigation included a series of tests during which tracer-laced water was released into a high-permeability zone within a horizontal injection borehole. The tracer concentration was monitored in the seepage collected in a...

In pressure sensitive reservoirs, interaction effects among the porous media flow field, the fracture field and the stress field can cause some specific flow characteristics entirely different from those in conventional reservoirs. Dynamic fracture behavior is one of them, which generates a change in the value of fracture aperture and even a variation in the anisotropy of permeability. In this ...

The primary objective of our current research is to develop a computational test bed for evaluating borehole techniques to enhance fluid flow and heat transfer in enhanced geothermal systems (EGS). Simulating processes resulting in hydraulic fracturing and/or the remobilization of existing fractures, especially the interaction between propagating fractures and existing fractures, represents a c...

Alterant tomography h*s been evaluated for its ability to de­ lineate itfsitu water flow paths in a fractured welded-tuff rock mass, The evaluation involved a field experiment in which tomographs of electromagnet attenuation factor (or attenuation rate) at 300 MHz were made before, during, and after the introduc­ tion to the rock of two different water-based tracers: a plain water and dye solut...

introduction: this study was conducted to determine the pattern of maxillofacial fractures in three age groups of adults, adolescents, and children, using ct scan images. methods: in this cross-sectional study, ct scan images of 230 patients with maxillofacial trauma during one year were examined in terms of the number and site of fractures. the patients were divided into three age groups, chil...

Unconventional gas resources from tight sand and shale gas reservoirs have received great attention in the past decade around the world, because of their large reserves as well as technical advances in developing these resources. As a result of improved horizontal drilling and hydraulic fracturing technologies, the progresses are being made towards commercial gas production from such reservoirs...

The generalized conceptual model for a fractured bedrock aquifer consists of low-permeability matrix blocks separated by highly permeable fractures that act as preferential pathways for ground water flow. The National Research Council (NRC 1996) summarizes three approaches for simulating ground water flow in fractured aquifers. The most common approach is to represent the system with an equival...