Magister Chirurgiae Dentium (MChD) / The literature shows that maxillofacial fractures in children are uncommon. Although the Department of Oral and Maxillofacial Surgery of the Faculty of Dentistry, of the University of the Western Cape, has been providing a service to the Red Cross Children’s Hospital (RXH) for the past twenty years, no study had been undertaken to determine the age, gender, number of patients per year, aetiology, patterns, and management of maxillofacial fractures at this institution. A retrospective records based study was undertaken to determine these features. This study accessed the records of patients seen at the trauma unit at RXH, from 1994 to 2003 inclusive, and referred for maxillofacial attention. One-hundred-and-five patient records were obtained and analyzed using the SPSS statistic package. One-hundred-and-twenty-seven fractures were recorded in one hundred and five patients. The age of the patients ranged from one to thirteen. Sixty-five male and forty female patients were seen. Dentoalveolar fractures were the most common fracture seen in both the midface and mandible. Midface fractures were more common than mandibular fractures. Falls, followed by motor vehicle accidents, were the most common cause of facial fractures. Most fractures were successfully managed by closed procedures. At this institution, nasal and frontal fractures have surprisingly little or no input from the Department of Oral and Maxillofacial Surgery. / South Africa

This report is to investigate the use of fracture mechanics parameters (fracture toughness, specific work of fracture) to characterize comminution process. Comminution is a very important industrial process and is extremely low in efficiency. Establishment of a crushing index based on fracture mechanics principles is of great significance for improved machine design and enhanced efficiency. Single particle fracture study has been reviewed because it is considered the most elementary process in and provides the basis for comminution. <p>Rock fragmentation can be best described by fracture mechanics principles and concepts. The most fundamental concept in fracture mechanics is fracture toughness. Extensive review has been done on the fracture toughness application to rock fragmentation problems, and has found it has not been successfully used in comminution process. Further study is necessary to investigate the link between comminution and fracture toughens. Interrelation of fracture. toughness with other rock properties has been studied. Loading rate effects on fracture toughness has also been reviewed. <p>Fracture toughness testing for rock materials has also been studied. The SCB (Semi-Circular Bend specimen) method has been selected for its sound analytical background and ease of operation. A experimental proposal is made based upon the survey results. Single particle fracture is proposed to be conducted on the Allis-Chalmers High Energy Crush Test System, which, compared with other test apparatus, more closely simulates the actual crushers. Detailed procedures on how to use the test system has been given in the report. / Master of Science

We found no significant excess of fractures among Rochester, MN, residents with diabetes mellitus initially recognized in 1950-1969, but more recent studies elsewhere have documented an apparent increase in hip fracture risk. To explore potential explanations for any increase in fractures, we performed an historical cohort study among 1964 Rochester residents who first met glycemic criteria for diabetes in 1970-1994 (mean age, 61.7 ± 14.0 yr; 51% men). Fracture risk was estimated by standardized incidence ratios (SIRs), and risk factors were evaluated in Andersen-Gill time-to-fracture regression models. In 23,236 person-years of follow-up, 700 diabetic residents experienced 1369 fractures documented by medical record review. Overall fracture risk was elevated (SIR, 1.3; 95% CI, 1.2-1.4), but hip fractures were increased only in follow-up beyond 10 yr (SIR, 1.5; 95% CI, 1.1-1.9). As expected, fracture risk factors included age, prior fracture, secondary osteoporosis, and corticosteroid use, whereas higher physical activity and body mass index were protective. Additionally, fractures were increased among patients with neuropathy (hazard ratio [HR], 1.3; 95% CI, 1.1-1.6) and those on insulin (HR, 1.3; 95% CI, 1.1-1.5); risk was reduced among users of biquanides (HR, 0.7; 95% CI, 0.6-0.96), and no significant influence on fracture risk was seen with sulfonylurea or thiazolidinedione use. Thus, contrary to our earlier study, the risk of fractures overall (and hip fractures specifically) was increased among Rochester residents with diabetes, but there was no evidence that the rise was caused by greater levels of obesity or newer treatments for diabetes.

No description available.

This dissertation discusses distal humeral epiphyseal injuries in children, i.e. lateral condylar fractures, medial condylar fractures, fracture-separation of the distal humeral epiphysis and T-condylar fractures. Medial and lateral epicondylar fractures, being apophyseal, are excluded. The research was done at the Red Cross Children's Hospital Trauma Unit. It was based on two clinical retrospective studies and one case report: a: 60 lateral condylar fractures presenting from 1984 to 1987 -were reviewed. b: 12 fracture-separations of the distal humeral epiphysis presenting from 1984 to 1989 were reviewed. c: One case report of a medial condylar fracture with associated elbow dislocation The distal humeral epiphysis is the second most commonly injured epiphysis in the body, after that of the distal radius (Peterson 1972). Supracondylar fractures are the most common fractures around the elbow in children, making up 65% of the total (Canale 1987). Lateral condyle fractures have an incidence of 17.4%, compared to 3.2% for medial condylar fractures and 0.8% for T-condylar fractures (Canale 1987). At the Red Cross Children's Hospital, 60 displaced supracondylar fractures, 20 lateral condylar fractures and 2 to 3 fracture-separations of the distal humeral epiphysis are seen every year. Medial condylar fractures are rare.

Fractures are ubiquitous in the subsurface, and they provide dominant pathways for fluid flow in low permeability formations. Therefore, fractures usually play an essential role in many engineering fields, such as hydrology, waste disposal, geothermal reservoir and petroleum reservoir exploitation. Since fractures are invisible and have variable sizes from micrometers to kilometers, there is limited knowledge of their structure. We aim to deepen the understanding of fracture networks in the subsurface from their topological structures, hydraulic connectivity and characteristics at different scales. We adopt the discrete fracture network method and develop an efficient C++ code, HatchFrac, to make in-depth investigations possible. We start from generating stochastic fracture networks by constraining fracture geometries with different stochastic distributions. We apply percolation theory to investigate the global connectivity of fracture networks. We find that commonly adopted percolation parameters are unsuitable for the characterization of the percolation state of complex fracture networks. We implement the concept of global efficiency to quantify the impact of fracture geometries on the connectivity of fracture networks. Furthermore, we constrain the fracture networks with geological data and geomechanics principles. We investigate the correlation of fracture intensities with different dimensionality and find that it is not feasible to obtain correct 3D intensity parameters from 1D or 2D samples. We utilize a deep-learning technique and propose a pixel-based detection algorithm to automatically interpret fractures from raw outcrop images. Interpreted fracture maps provide abundant resources to investigate fracture intensities, lengths,orientations, and generations. For large scale faults, we develop a method to generate fault segments from a rough fault trace on a seismic map. Accurate fault geometries have significant impacts on damage zones and fault-related flow problems. For small scale fractures, we consider the impact of fracture sealing on the percolation state of orthogonal fracture networks. We emphasize the importance of non-critically stressed and partially sealed fractures, which are usually neglected because usually they are nonconductive. However, with significant stress perturbations, those noncritically stressed and partially sealed fractures can also contribute to the production by enlarging the stimulated reservoir volume.

No description available.

Traditional fracture testing in the field of athletic training relies heavily on subjective responses of the athlete. Percussion and compression type tests rely on the athlete stating an increase in pain which represents a positive symptom of a possible fracture. The tuning fork and stethoscope method relied purely on a subjective assessment from the examiner. The purpose of the study was to determine if the use of a 128Hz tuning fork and stethoscope were effective evaluation tools in the assessment of possible fractures as compared to the traditional fracture tests that are used in the athletic training field. A vibrating 128 Hz tuning fork was placed on the bone/area where swelling was minor to facilitate good cortical bone contact. Then the conical bell of a stethoscope was placed on the opposite end on the bone or bones. A diminished sound arising from the injured bone as compared to the uninjured represented a positive sign for a possible fracture. Traditional fracture testing was performed and noted. An x-ray, diagnosed by an orthopedic physician, supported the validity of the tuning fork and traditional fracture testing methods. The attempt was to see what testing method, the tuning fork and stethoscope or traditional fracture testing, was a more valid evaluation tool when it comes to fractures. This study was performed at a university's athletic training room and a local orthopedic center. The study consisted of any subject between the ages of 18-85 that presented with a suspected fracture at either testing facilities. The current study examined 37 male and female subjects whose age ranged from 18-85 years old. The long bones that were tested in this research were as follows: the phalanges of the hand and foot, metacarpals, metatarsals, humerus, radius, ulna, fibula (including the lateral malleolus), and tibia (including the medial malleolus). The tuning fork and stethoscope was shown to be an effective and valid tool for evaluating possible fractures by yielding a success rate of 89.2% when compared to an x-ray. The percussion and compression fracture testing methods yielded only a success rate of 67.6% and 64.9% respectively. / Ph. D.

No description available.

The design of effective quality management strategies in groundwater systems is crucial, as clean water is essential for livelihood, health, and development. Colloids represent a class of contaminants that might be pathogenic or benign. Colloids can also enhance or inhibit the transport of dissolved contaminants in groundwater, which has inspired the use of benign colloids in the remediation of contaminated aquifers. Reliable modelling of colloid behavior is therefore essential for the design of effective remediation strategies, both those employing benign colloids and those aiming at the removal of pathogenic colloids. While colloid transport is controlled by groundwater velocity, colloid retention is governed by the physical and chemical properties of the aquifer together with those of the colloid. The present study aims at enhancing the reliability of modelling colloid behavior in fractured aquifers through: i) developing a synchronization-based framework that can effectively identify hydraulic connections within the aquifer; ii) developing a mathematical model for the relationship between the fraction of colloids retained along a fracture (Fr) and the parameters describing the aquifer’s physical and chemical properties; iii) developing an analytical model for the relationship between Fr and the coefficient describing irreversible colloid deposition in single fractures; and, iv) developing a numerical technique that can efficiently simulate colloid behavior in single fractures and fracture networks under different physical, chemical, and matrix conditions. The performance of the synchronization-based framework, mathematical and analytical models, and the numerical technique was assessed separately for different verification cases, and the corresponding efficacy was confirmed. Coupling the tools developed in the present study enables the reliable prediction of colloid behavior in response to changes in the groundwater-colloid-fracture system’s physical and chemical properties, which can aid in understanding how to manipulate the system’s properties for the effective design of groundwater quality management and remediation strategies. / Thesis / Doctor of Philosophy (PhD) / Microorganisms, microplastics, clay, and fine silt are classified as colloids within the spectrum of contaminants that might exist in groundwater. Although some colloids are benign (e.g., clay and fine silt), they can still affect the groundwater quality and aquifer porosity. Colloids can also enhance or inhibit the migration of other contaminants in groundwater because of their high adsorption capacity. Several remediation strategies are being envisioned to remove pathogenic colloids and eliminate other contaminants adsorbed onto benign colloids, where effective design of such strategies requires reliable models of colloid behavior. The present study aims at enhancing the reliability of simulating colloid behavior in fractured aquifers through: i) developing models that capture the effects of the aquifer’s physical and chemical properties on colloid behavior; and, ii) designing a framework that improves the reliability of aquifer conceptualization. Effective remediation strategies can then be designed for contaminated fractured aquifers based on the developed tools.