Metallurgical parameters,mechanical properties and machinability of ductile cast iron

Results on the effect of solidification cooling rate on the microstructure, mechanical properties and machinability of spheroidal graphite (SG) iron have been presented. The effect of ferritic heat treatment on the same properties has been also investigated. The microstructural observation, tensile properties and hardness values of the present SG iron has been developed. The tool life criterion was used as a measure of machinability. It was found that during turning of SG iron by using a single point cutting tool, its life increased with decreasing the solidification cooling rate for both sand and metal moulds. The tool life was found to be significantly affected by the variation of nodule characteristics. A decrease in tool life due to an increase of nodule count was observed. The tool life was found to be directly proportional to the ductility of SG iron whether for the as cast or ferritic heat-treated ingots.     

Recursive linear smoothed Newton predictors for polynomialextrapolation

Newton predictors have considerable gain at the higher frequencies, which reduces their applicability to practical signal processing where the narrowband primary signal is often corrupted by additive wideband noise. Two modifications that can be used to extrapolate low-order polynomials have been proposed. In both approaches, the highest order difference of successive input samples, approximating the constant nonzero derivative, is smoothed before it is added to the lower order differences, reducing the undesired noise gain. The linear smoothed Newton (LSN) predictor is extended in this work by including a recursive term in the basic transfer function and cascading the rest of the successive difference paths with appropriately delayed extrapolation filters of corresponding polynomial orders. This leads to computationally efficient IIR predictors with significantly lowered gain at the higher frequencies. The recursive predictor is analyzed in the time and frequency domains and compared to the other predictors     

Day-night variations of behavioral and autonomic thermoregulatory responses to lipopolysaccharide in rats

This study investigated the day-night differences in behavioral and autonomic thermoregulatory responses to bacterial lipopolysaccharide (LPS) in rats. Male rats were housed individually in cages with a 12: 12 h light dark cycle at an ambient temperature of 24 degrees C. The rats were placed in a box with a temperature gradient and intraperitoneally injected with LPS (10 micrograms/kg). The preferred ambient temperature (Tpr) was estimated by the location of the rats in the box, and intraperitoneal temperature (Tb) was measured by a biotelemetry system. Measurements were taken during the light and dark phases of the day. LPS produced fever in both phases. The magnitude of rise in Tb did not differ between the two periods. In the dark phase, Tpr significantly increased during the development of fever and decreased during the defervescence, while it did not change throughout the febrile course during the light phase. In a separate experiment, rats were loosely restrained and placed in a direct calorimeter. Their colonic temperature (Tcol), evaporative and nonevaporative heat loss and heat production were measured before and after intraperitoneal injections of LPS (10 micrograms/kg). Measurements were taken during the light and dark phases of the day. LPS induced fever in both phases. The magnitude of change in T col, heat loss, and heat production due to LPS did not differ between the two periods. These results suggest that the fertile response of rats to intraperitoneal LPS is not affected by the time of day. However, it seems that during LPS-induced fever, thermoregulatory behavior is not fully activated during the light phase of the day.     

Estimating areal means and variances of forest attributes using the k-Nearest Neighbors technique and satellite imagery

The k-Nearest Neighbor (k-NN) technique has become extremely popular for a variety of forest inventory mapping and estimation applications. Much of this popularity may be attributed to the non-parametric, multivariate features of the technique, its intuitiveness, and its ease of use. When used with satellite imagery and forest inventory plot data, the technique has been shown to produce useful estimates of many forest attributes including forest/non-forest, volume, and basal area. However, variance estimators for quantifying the uncertainty of means or sums of k-NN pixel-level predictions for areas of interest (AOI) consisting of multiple pixels have not been reported. The primary objectives of the study were to derive variance estimators for AOI estimates obtained from k-NN predictions and to compare precision estimates resulting from different approaches to k-NN prediction and different interpretations of those predictions. The approaches were illustrated by estimating proportion forest area, tree volume per unit area, tree basal area per unit area, and tree density per unit area for 10-km AOIs. Estimates obtained using k-NN approaches and traditional inventory approaches were compared and found to be similar. Further, variance estimates based on different interpretations of k-NN predictions were similar. The results facilitate small area estimation and simultaneous and consistent mapping and estimation of multiple forest attributes.     

Correlation relations for estimating the content of plutonium isotopes in fallout due to the Chernobyl accident

The possibility of determining the total α activity A(^239,240Pu) of ²³⁹Pu + ²⁴⁰Pu according to the γ radiation of ¹⁰³Ru and ¹⁰⁶Ru is examined. The statistical properties of the experimental ratios of the activities ρ = A(¹⁰⁶Ru)/A(¹⁰³Ru) are investigated. The distribution of the experimental ratios is similar to the theoretical ratios for fuel and close to a Gaussian distribution with average value 〈p〉 = 0.22 and standard deviation Δ ∼ 0.06. This ratio is used to obtain a relation for estimating A(^239,240Pu) from the γ activity A(¹⁰³Ru). A theoretical analysis is made of the experimental data for the southern raions of Gomel oblast. It is shown that given a good statistical sample of measurements of the γ activity of ¹⁰³Ru it is possible to estimate the average value of the γ activity A(^239,240Pu) and with probability 0.95 the interval of the possible values of this activity. __________ Translated from Atomnaya énergiya, Vol. 103, No. 4, pp. 255–259, October, 2007.     

Requirements and Services for Metadata Management

Knowledge-intensive applications pose new challenges to metadata management, including distribution, access control, uniformity of access, and evolution in time. This paper identifies general requirements for metadata management and describes a simple model and service that focuses on RDF metadata to address these requirements.     

Pulse control problems under ellipsoidal constraints: Constraint parameters sensitivity

Consideration is given to pulse control problems for the tube of trajectories of the linear differential system under incomplete information on the initial data. Apart from the ordinary requirement for boundedness of variation, a special constraint of the ellipsoidal type is imposed on control actions; at this constraint, vectors of jumps of generalized controls belong to the specified ellipsoid of the corresponding finite-dimensional space. The dependence of the variation of optimal pulse control that solves the control problem for the tube of trajectories on parameters of the ellipsoidal constraint on admissible controls is studied.