The influence of polycrystal grain size on several mechanical properties of materials

The ductile-brittle transition, hardness, fatigue, and creep behavior of polycrystalline materials are known to be influenced under certain conditions by the polycrystal grain size. These properties have been correlated, historically, with the material stress-strain behavior. The (Hall-Petch) stress-grain size relations are useful for describing the complete stress-strain behavior for polycrystals and, therefore, these relations provide a reference for understanding the manner in which these other properties should also depend on the grain size. In some cases, the grain size dependence of a particular property follows directly from this connection.     

Technologies and the development of the Automated Metadata Indexing and Analysis (AMIA) system

The Automated Metadata Indexing and Analysis (AMIA) project aims to provide an effective digital asset management (DAM) tool for large digital asset databases. We began with text-based indexing since it is still the most reliable approach as compared with other content-based media features. AMIA not only searches for the text of the file name, but also utilizes embedded information such as the metadata in Maya files. The AMIA system builds a linked map between all dependency files. We present an approach of preserving previously established metadata created by the old DAM tools, such as AlienBrain, and integrating them into the new system. Findings indicate that AMIA has significantly improved search performance comparing to previous DAM tools. Finally, the ongoing and future work in the AMIA project is described.     

Static mixers for laminar flow reactors with low aspect ratios

Conventional static mixers typically require high length to diameter ratios to be effective. This paper considers static mixers design to increase first appearance times in short, fat reactors. Three types are considered: conical baffles and annular baffles for tubular reactors and axial baffles for reactors with a rectangular cross-section. Relatively simple designs allow production increases (or reactor volume decreases) on the order of 20–50%.     

Simulation Based Investigation of Triple Heterojunction TFET (THJ-TFET) for Low Power Applications

Silicon - We designed a new model tunnel field-effect transistor (TFET) based on Triple Heterojunction Tunnel Field Effect Transistor (THJ-TFET) is investigated and designed in this paper. This...     

Orthopedic management of osteopetrosis: results of a survey and review of the literature

Osteopetrosis or Albers-Schonberg disease is a rare hereditary disorder of osteoclast function in which resorption of bone is diminished, resulting in abnormally dense bones. The condition is known to occur in at least four recognizable clinical patterns, each of which is variable. The optimal treatment of fractures and of bone deformity in these patients has not previously been made clear. To determine appropriate orthopedic management of the condition, we conducted a survey of the membership of the Pediatric Orthopedic Society of North America. The combined experience of 57 surgeons who treated 79 patients with osteopetrosis was compiled. Four femoral neck fractures treated by closed reduction and internal fixation had a satisfactory result, but three treated nonoperatively developed varus and required osteotomy. A total of 20 hips was treated for coxa vara by various means, none of which was free of complications. Valgus osteotomy, when used as the primary treatment for coxa vara, was the most consistently satisfactory procedure, whereas in situ pinning failed in two of three hips. Fourteen subtrochanteric fractures and 31 other fractures of the femur were treated. Good results were reported with traction or casting or both in the majority of those fractures. Twenty-nine tibia fractures were treated successfully, the majority by nonoperative means. Upper extremity fractures healed well with closed reduction and casting. Vertebral fractures, spondylolysis, and back pain were most frequently treated without surgery.     

A correlation between electrochemical parameters and stress corrosion cracking

Measurements of relaxation times for passivation, by means of a.c. impedance measurements, have been made and a correlation with susceptibility to stress corrosion cracking obtained, for low carbon steels in carbonate/bicarbonate solutions at 70°C.     

A pilot study of the efficacy of residuum lodges for managing sediment delivery to impoundment reservoirs

Residuum lodges comprise small dams constructed on feeder streams immediately before they enter a reservoir, behind which ponds form, where sediment is deposited. Despite their construction on many impoundment reservoirs (IRE) and catchwaters, little research has previously investigated their efficacy at removing sediments from feeder streams. The current pilot study has, therefore, been carried out at an IRE supplying Halifax, West Yorkshire, UK, where a residuum lodge was recently cleaned out. Sediment concentrations reaching the reservoir were reduced by up to 42% although no certain impacts were noted on the other water quality variables that were measured. Moreover, it was found that the clearance operation did not result in the release of excessive quantities of sediment into the reservoir. It was estimated that the cleared residuum lodge would take 12 years to refill. A survey of other residuum lodges in the Yorkshire region showed there to be considerable differences in their remaining capacities.     

Statistical algorithm for nonuniformity correction in focal-plane arrays.

A statistical algorithm has been developed to compensate for the fixed-pattern noise associated with spatial nonuniformity and temporal drift in the response of focal-plane array infrared imaging systems. The algorithm uses initial scene data to generate initial estimates of the gain, the offset, and the variance of the additive electronic noise of each detector element. The algorithm then updates these parameters by use of subsequent frames and uses the updated parameters to restore the true image by use of a least-mean-square error finite-impulse-response filter. The algorithm is applied to infrared data, and the restored images compare favorably with those restored by use of a multiple-point calibration technique.