Premature failure of Aluminum Core Steel Reinforced wires

During torsion test several galvanized Aluminium Core Steel Reinforced (ACSR) wires of 3.54 mm diameter (drawn from 5.5 wires) have failed after 16 twists as against the normal of about 28 twists. The premature failure is believed to be due to acid exposure prior to the galvanizing. In order to minimize the problem 0.2% Cr is added into the steel composition. The failure analysis of the sample showed that hydrogen exposure during pickling process prior to the galvanizing operation is not the proper reason for failure. Further study showed that addition of chromium into the steel composition enhances the pre mature failure life but that is also much above than the purview of present plant operating conditions. The microstructural study shows that the premature failure specimen has disaligned and broken lamellae with globular cementite which creates an array of voids. These voids hinder rotation during torsion thus leading to brittle fracture.     

Biological effects of a novel intestinal peptide--inhibiting enterocytogenin on cultured 3T3 mouse fibroblasts and L5178Y mouse lymphoma cells

Twenty-one cervical spines were collected from fresh cadavers (12 male, nine female), their ages ranging from 10 to 90 years (mean 49.47). After removing muscle debris from the spines, they were mounted and tested on a device to passively reproduce the main movements of the spine. The degree of motion in flexion-extension and lateral bending significantly decreased from group A (ages 10-49 years) to group B (51-90 years) (p < 0.005) and was directly correlated with the amount of cervical spine degenerative alterations. The incidence of these alterations, classified according to Lysell (1969), was highest at C5-6. On the testing machine, dynamic angiography of the vertebral artery showed an impingement with extrinsic compression of the vessels in four of 28 successful injections. The histologic serial sections of the uncus showed a characteristic pattern of ossification-deformation: a newly formed cartilaginous tissue tipping the apex of the uncus, forming a double protruding contour of the apex, rapidly ossifying, and appearing to deform outward together with the disk degeneration and consequently decreasing in height.     

NC algorithms for real algebraic numbers

Characterizing real algebraic numbers by a sign-sequence (according to Thom's lemma), using a variant of Ben Or Kozan and Reif algorithm for reducing the solving of systems of polynomial inequalities to the problem of counting real zeroes satisfying one polynomial inequality, and using a multivariate Sturm theory generalizing Hermite quadratic forms method for counting real zeroes, we prove that the computations on real algebraic numbers are in NC.Partially supported by DGICyT PB 89/0379, UPC PR9014, and the ESPRIT BRA program of the EC under contract no. 3075, project ALCOMPartially supported by NSF CCR-90-02819Supported by AT&T Bell Fellowship, and partially supported by NSA MDA904-89-H-2030     

Operative arthroscopy into the next century

Until 10 years ago, operative arthroscopy was largely restricted to the knee. However, shoulder arthroscopy can now stabilize instability and repair rotator cuff tears. Operative procedures are seven being extended into the wrist and ankle.     

Studies on immobilization of thorium in barium borosilicate glass

The barium borosilicate glass (BBS) matrix has shown considerable solubility of ThO₂ at 1000 °C. As seen by X-ray diffractometry (XRD) and Electron probe micro analysis (EPMA) up to 15.86 wt% of ThO₂ could be dissolved in this matrix. The homogeneity of thoria loaded glass was convincingly ascertained by EPMA. Attempts to load more than 16 wt% ThO₂ led to the phase separation of crystalline phases identified as major phase of ThO₂ and minor percentage of ThSiO₄ phase with altogether different morphologies, as seen by XRD. Interestingly, the back scattered images of thorite crystals point towards the presence of chemical zoning. The results being reported in this paper are of interest especially with respect to immobilization of other actinides in borosilicate glass matrix.     

Cardiogenic oscillation phase relationships during single-breath tests performed in microgravity

We studied the phase relationships of the cardiogenic oscillations in the phase III portion of single-breath washouts (SBW) in normal gravity (1 G) and in sustained microgravity (microG). The SBW consisted of a vital capacity inspiration of 5% He-1.25% sulfurhexafluoride-balance O2, preceded at residual volume by a 150-ml Ar bolus. Pairs of gas signals, all of which still showed cardiogenic oscillations, were cross-correlated, and their phase difference was expressed as an angle. Phase relationships between inspired gases (e.g., He) and resident gas (n2) showed no change from 1 G (211 +/- 9 degrees) to microG (163 +/- 7 degrees). Ar bolus and He were unaltered between 1 G (173 +/- 15 degrees) and microG (211 +/- 25 degrees), showing that airway closure in microG remains in regions of high specific ventilation and suggesting that airway closure results from lung regions reaching low regional volume near residual volume. In contrast, CO2 reversed phase with He between 1 G (332 +/- 6 degrees) and microG (263 +/- 27 degrees), strongly suggesting that, in microG, areas of high ventilation are associated with high ventilation-perfusion ratio (VA/Q). This widening of the range of VA/Q in microG may explain previous measurements (G.K. Prisk, A.R. Elliott, H.J.B. Guy, J.M. Kosonen, and J.B. West J. Appl. Physiol. 79: 1290-1298, 1995) of an overall unaltered range of VA/Q in microG, despite more homogeneous distributions of both ventilation and perfusion.