Thermodynamic properties of interstitial elements in the refractory metals Semiannual report, 1 Dec. 1967 - 31 May 1968

Thermodynamic behavior of interstitial elements in Mo, W, Nb, and T

Local Guarantees in Graph Cuts and Clustering

Correlation Clustering is an elegant model that captures fundamental graph cut problems such as Min $s-t$ Cut, Multiway Cut, and Multicut, extensively studied in combinatorial optimization. Here, we are given a graph with edges labeled $+$ or $-$ and the goal is to produce a clustering that agrees with the labels as much as possible: $+$ edges within clusters and $-$ edges across clusters. The classical approach towards Correlation Clustering (and other graph cut problems) is to optimize a global objective. We depart from this and study local objectives: minimizing the maximum number of disagreements for edges incident on a single node, and the analogous max min agreements objective. This naturally gives rise to a family of basic min-max graph cut problems. A prototypical representative is Min Max $s-t$ Cut: find an $s-t$ cut minimizing the largest number of cut edges incident on any node. We present the following results: $(1)$ an $O(\sqrt{n})$-approximation for the problem of minimizing the maximum total weight of disagreement edges incident on any node (thus providing the first known approximation for the above family of min-max graph cut problems), $(2)$ a remarkably simple $7$-approximation for minimizing local disagreements in complete graphs (improving upon the previous best known approximation of $48$), and $(3)$ a $1/(2+\varepsilon)$-approximation for maximizing the minimum total weight of agreement edges incident on any node, hence improving upon the $1/(4+\varepsilon)$-approximation that follows from the study of approximate pure Nash equilibria in cut and party affiliation games

Multilayer article having stabilized zirconia outer layer and chemical barrier layer

A multilayer article includes a substrate that includes at least one of a ceramic compound and a Si-containing metal alloy. An outer layer includes stabilized zirconia. Intermediate layers are located between the outer layer and the substrate and include a mullite-containing layer and a chemical barrier layer. The mullite-containing layer includes 1) mullite or 2) mullite and an alkaline earth metal aluminosilicate. The chemical barrier layer is located between the mullite-containing layer and the outer layer. The chemical barrier layer includes at least one of mullite, hafnia, hafnium silicate and rare earth silicate (e.g., at least one of RE.sub.2 SiO.sub.5 and RE.sub.2 Si.sub.2 O.sub.7 where RE is Sc or Yb). The multilayer article is characterized by the combination of the chemical barrier layer and by its lack of a layer consisting essentially of barium strontium aluminosilicate between the mullite-containing layer and the chemical barrier layer. Such a barium strontium aluminosilicate layer may undesirably lead to the formation of a low melting glass or unnecessarily increase the layer thickness with concomitant reduced durability of the multilayer article. In particular, the chemical barrier layer may include at least one of hafnia, hafnium silicate and rare earth silicate

Skillful management of exodontia complication to prevent dreadful sequelae

Successful surgical treatments depend upon accurate diagnosis, judicious treatment planning, selection and execution of an appropriate surgical technique, and on a well monitored post-operative period. However, despite these precautions, extraction of teeth (particularly third molar) is exposed to the accidents and complications common to all buccomaxillary and facial interventions. A maxillary third molar may be displaced in maxillary sinus, nearby soft tissue, or may migrate in a superioposterior direction towards paraphyrangeal space, or infratemporal fossa. Dislocating the maxillary third molar in infratemporal fossa is one of the worst nightmare as this area has complex anatomy consisting of vital neurovascular tissues and complex fascial spaces. The extent of displacement depends upon anatomical conditions as well as direction and amount of force applied. Complication arises from error in judgment, improper use of instruments, the application of extreme force or failure to obtain full visualization before acting. Various researchers have given their opinion regarding immediate or delayed removal of tooth pushed in infratemporal fossa but almost all agree that each case should be weighed independently for risk and reward before attempting. Here we present a case in which intraoral approach was taken to retrieve the displaced tooth thus preventing potentially dreadful complications

An Assessment of Knowledge and Practices Regarding Tuberculosis in the Context of RNTCP Among Non Allopathic Practitioners in Gwalior District

Introduction: India has the highest TB burden accounting for one-fifth of the global incidence with an estimated 1.98 million cases. Non- allopathic practitioners are the major service providers especially in rural and peri-urban areas, treating not just patients of diarrhea, respiratory infections and abdominal Pain but also of tuberculosis. Objectives: To assess the knowledge of sign and symptoms of TB and its management as per the RNTCP guidelines and to assess the practicing pattern regarding tuberculosis. Material & Methods: The present was carried out among the registered non allopathic practitioners providing their services in Gwalior District during the study period. A total of 150 non allopathic practitioners of various methods from both government and private sectors were interviewed using a pre-designed, pre-tested semi-structured questionnaire. The information was collected on the General profile of the participant, knowledge about signs and symptoms of TB and its management, practices commonly adopted in the management and their views on involvement of non allopathic practitioners in RNTCP programme. Result: The average score of government practitioners was 7.3 compared to 4.6 by private practitioners. There was a statistically significant difference between the two group on issue related to the management of TB patients as per the RNTCP guidelines. Government practitioners relied mostly on sputum examination for diagnosis and follow up compared to private practitioners who chose other modalities like X-ray, blood examination for this work. Conclusion: There is a gap in knowledge and practices of practitioners of both the sectors. Some serious efforts were required to upgrade the knowledge of non allopathic practitioners if the government is serious about controlling tuberculosis in India

Analysis and test evaluation of the dynamic response and stability of three advanced turboprop models

Results of dynamic response and stability wind tunnel tests of three 62.2 cm (24.5 in) diameter models of the Prop-Fan, advanced turboprop, are presented. Measurements of dynamic response were made with the rotors mounted on an isolated nacelle, with varying tilt for nonuniform inflow. One model was also tested using a semi-span wing and fuselage configuration for response to realistic aircraft inflow. Stability tests were performed using tunnel turbulence or a nitrogen jet for excitation. Measurements are compared with predictions made using beam analysis methods for the model with straight blades, and finite element analysis methods for the models with swept blades. Correlations between measured and predicted rotating blade natural frequencies for all the models are very good. The IP dynamic response of the straight blade model is reasonably well predicted. The IP response of the swept blades is underpredicted and the wing induced response of the straight blade is overpredicted. Two models did not flutter, as predicted. One swept blade model encountered an instability at a higher RPM than predicted, showing predictions to be conservative

Contributions to the mixed-alkali effect in molecular dynamics simulations of alkali silicate glasses

The mixed-alkali effect on the cation dynamics in silicate glasses is analyzed via molecular dynamics simulations. Observations suggest a description of the dynamics in terms of stable sites mostly specific to one ionic species. As main contributions to the mixed--alkali slowdown longer residence times and an increased probability of correlated backjumps are identified. The slowdown is related to the limited accessibility of foreign sites. The mismatch experienced in a foreign site is stronger and more retarding for the larger ions, the smaller ions can be temporarily accommodated. Also correlations between unlike as well as like cations are demonstrated that support cooperative behavior.Comment: 10 pages, 12 figures, 1 table, revtex4, submitted to Phys. Rev.

Thermal Expansion and Thermal Conductivity of Rare Earth Silicates

Rare earth silicates are considered promising candidate materials for environmental barrier coatings applications at elevated temperature for ceramic matrix composites. High temperature thermophysical properties are of great importance for coating system design and development. In this study, the thermal expansion and thermal conductivity of hot-pressed rare earth silicate materials were characterized at temperatures up to 1400 C. The effects of specimen porosity, composition and microstructure on the properties were also investigated. The materials processing and testing issues affecting the measurements will also be discussed