Evaluation of the reactivity of titanium with mould materials during casting

A methodology for evaluating the reactivity of titanium with mould materials during casting has been developed. Microhardness profiles and analysis of oxygen contamination have provided an index for evaluation of the reactivity of titanium. Microhardness profile delineates two distinct regions, one of which is characterised by a low value of hardness which is invariant with distance. The reaction products are uniformly distributed in the metal in this region. The second is characterised by a sharp decrease in microhardness with distance from the metal-mould interface. It represents a diffusion zone for solutes that dissolve into titanium from the mould. The qualitative profiles for contaminants determined by scanning electron probe microanalyser and secondary ion mass spectroscopy in the as-cast titanium were found to be similar to that of microhardness, implying that microhardness can be considered as an index of the contamination resulting from metal-mould reaction.     

The roles of computerized support systems: a decision subprocess-based analysis

This paper analyses the potential roles of computerized systems in supporting the decision-making process. Toward this end, we propose an expository process model of decision-making and develop a framework that provides the infrastructure for the analysis. The proposed process model draws on two well-known models in the literature and enumerates eight distinct phases in decision-making. The framework developed is based on an integration of this process model with Simon's notion of 'decision-structuredness'. Unlike any of the existing frameworks, the suggested framework permits a micro-level analysis of support system roles. The analysis is intended as a pre-design guide, to help systems developers and users to identify support potential and possibilities, and to target their activities accordingly.     

Measurement of the temperature field induced by dynamic crack growth in Beta-C titanium

The temperature increase at the tip of a dynamically propagating crack may have a significant effect on a material's mechanical properties, and hence on its dynamic fracture toughness. In order to start to understand this phenomena, measurements of the temperature field at the tip of a dynamically growing crack in Beta-C titanium alloy were performed using a linear array of high speed infrared detectors. The results show that a maximum temperature of 450°C is reached at the crack tip. In addition, the dynamic fracture toughness was measured for crack speeds from 0 to 500 m/s. In this speed range, the toughness appears to be constant. Estimates of the crack tip energy release rate and plastic strain rate are made using analysis of the experimental data.     

Antihypertensive agent moxonidine enhances muscle glucose transport in insulin-resistant rats

The sympatholytic antihypertensive agent moxonidine, a centrally acting selective I1-imidazoline receptor modulator (putative agonist), may be beneficial in hypertensive patients with insulin resistance. In the present study, the effects of chronic in vivo moxonidine treatment of obese Zucker rats--a model of severe glucose intolerance, hyperinsulinemia and insulin resistance, and dyslipidemia--on whole-body glucose tolerance, plasma lipids, and insulin-stimulated skeletal muscle glucose transport activity (2-deoxyglucose uptake) were investigated. Moxonidine was administered by gavage for 21 consecutive days at 2, 6, or 10 mg/kg body weight. Body weights in control and moxonidine-treated groups were matched, except at the highest dose, at which final body weight was 17% lower in the moxonidine-treated animals compared with controls. The moxonidine-treated (6 and 10 mg/kg) obese animals had significantly lower fasting plasma levels of insulin (17% and 19%, respectively) and free fatty acids (36% and 28%, respectively), whereas plasma glucose was not altered. During an oral glucose tolerance test, the glucose response (area under the curve) was 47% and 67% lower, respectively, in the two highest moxonidine-treated obese groups. Moreover, glucose transport activity in the isolated epitrochlearis muscle stimulated by a maximally effective insulin dose (13.3 nmol/L) was 39% and 70% greater in the 6 and 10 mg/kg moxonidine-treated groups, respectively (P<.05 for all effects). No significant alterations in muscle glucose transport were elicited by 2 mg/kg moxonidine. These findings indicate that in the severely insulin-resistant and dyslipidemic obese Zucker rat, chronic in vivo treatment with moxonidine can significantly improve, in a dose-dependent manner, whole-body glucose tolerance, possibly as a result of enhanced insulin-stimulated skeletal muscle glucose transport activity and reduced circulating free fatty acids.     

Unsupervised image-set clustering using an information theoretic framework.

In this paper, we combine discrete and continuous image models with information-theoretic-based criteria for unsupervised hierarchical image-set clustering. The continuous image modeling is based on mixture of Gaussian densities. The unsupervised image-set clustering is based on a generalized version of a recently introduced information-theoretic principle, the information bottleneck principle. Images are clustered such that the mutual information between the clusters and the image content is maximally preserved. Experimental results demonstrate the performance of the proposed framework for image clustering on a large image set. Information theoretic tools are used to evaluate cluster quality. Particular emphasis is placed on the application of the clustering for efficient image search and retrieval.     

Volume effects and associations in liquid alloys

The regular associated solution model for binary systems has been modified by incorporating the size of the complex as an explicit variable. The thermodynamic properties of the liquid alloy and the interactions between theA _μB type of complex and the unassociated atoms in anA-B binary have been evaluated as a function of relative size of the complex using the activity coefficients at infinite dilution and activity data at one other composition in the binary. The computational procedure adopted for determining the concentration of clusters and interaction energies in the associated liquid is similar to that proposed by Lele and Rao. The analysis has been applied to the thermodynamic mixing functions of liquid Al-Ca alloys believed to contain Al₂Ca associates. It is found that the size of the cluster significantly affects the interaction energies between the complex and the unassociated atoms, while the equilibrium constant and enthalpy change for the association reaction exhibit only minor variation, when the equations are fitted to experimental data. The interaction energy between unassociated free atoms remains virtually unaltered as the size of the complex is varied between extreme values. Accurate data on free energy, enthalpy, and volume of mixing at the same temperature on alloy systems with compound forming tendency would permit a rigorous test of the proposed model.     

Psychosocial functioning in children of alcoholic fathers.

T. Jacob and K. Leonard (1986) reported that children of alcoholic fathers were comparable to children of depressed fathers in their psychosocial functioning. These results, however, were based on a relatively homogeneous sample. In the current study, previous results were extended by examining a sample of alcoholic fathers who were not screened for additional paternal psychiatric disorders or for major maternal psychopathology. Children in the unscreened and screened samples could not be distinguished in their functioning, and the majority of children of alcoholic fathers were functioning in the normal range of the Child Behavior Checklist. Given the heterogeneous adjustment in children of alcoholic fathers, the authors examined a range of factors that might protect against or exacerbate the risk associated with paternal alcoholism. Maternal depression and certain demographic characteristics were associated with poorer child functioning, particularly for male children. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

(BETS)2[RuX5NO] (X = Cl, Br): An Explanation of Different Conductive Properties Through Structural and Spectroscopic Studies

For the development of new crystal and electronic structures in molecular conductors, dimeric tetrathiafulvalene (TTF) and tetraselenafulvalenes (TSFs)1–3 linked by single or double methyl antimony bridge(s) have been prepared and their neutral crystal structures have been investigated. The donor2 (cis-2) forms a metallic cation radical salt with tetracyanoquinodimethane (TCNQ) containing one-dimensional array interactions.     

Cracking tendency of HSC: Tensile strength and self generated stress in the period of setting and early hardening

It is well known that horizontal surfaces of high strength concrete (HSC) are susceptible to cracking in the time before and during setting. It appears that there are two critical time periods for such cracking: An early period ranging from placing to an hour or two, and a late period that covers the setting time and early hardening. The latter is considered here. In this period, the cracking risk may be assessed from the ratio between strain (the volume change) and tensile strain capacity, or from the ratio between stress generated from the volume change at restraint, and the tensile strength. All these parameters were measured. It is shown that relatively moderate volume changes of HSC-surfaces caused by drying plus cooling, generate restraining stress that may exceed the tensile strength, and thus, generate failure. The results indicate that crack risk assessment from stress/strength is more reliable than using strain/strain capacity. The starting point of tensile strength evolution of hardened concrete seems to coincide fairly well with the initial setting time. Also, the tensile strain capacity reaches a low level at this point, but continues descending for another hour or more.     

The next challenge for newborn intensive care in Alaska: improving the survival of the larger neonate

Using information from our database, a review of mortality for the Newborn Intensive Care Unit at Providence Alaska Medical Center was conducted for 1987-1996. There has been a significant decline in mortality over the last decade (p = 0.003). An analysis of mortality by birthweight and gestational age groups demonstrated a decline in mortality (p = 0.005) for infants with birthweight < 2 kg and infants < or = 34 weeks gestation, but no change for infants > or = 2 kg and > or = 35 weeks gestation. As a result, larger and more mature babies now account for an increasing proportion of NICU deaths. For 1995 and 1996 the major contributors to mortality for the smaller neonates were respiratory distress syndrome and congenital and nosocomial sepsis/pneumonia. The major contributors to mortality for larger neonates were persistent pulmonary hypertension of the newborn, congenital heart disease, congenital diaphragmatic hernia, and primary birth asphyxia. A majority of deaths in the larger neonates were due to non-lethal causes. We contend that improved survival in the larger neonate is an important and achievable goal. The introduction of ECMO (Extracorporeal Membrane Oxygenation) for the NICU and a focused review of the neonatal cardiac program offers the best possible potential for achieving this goal.