Evaluation of critical orifices made from sections of hypodermic needles

Levamisole, a potentiator of cell-mediated immunity, has been reported to increase survival in patients with resectable carcinoma of the lung. Cell-mediated immunity can be measured in vitro by the leukocyte migration inhibition test. We have previously reported that this test detects cell-mediated immunity to human lung tumor antigens. In the present studies, patients with lung cancer were treated with Levamisole. Their leukocytes were evaluated in the leukocyte migration inhibition assay before, during, and following Levamisole therapy. Small increases in cell-mediated immunity were observed when patients had a high pre-existing tumor immunity. When tumor-associated reactivity was absent prior to therapy, larger increases were measured. Although Levamisole is a nonspecific immunostimulant, these data indicate that in vitro anti-tumor immune responses are enhanced by Levamisole therapy. Augmentation of cell-mediated immunity to tumor antigens may explain the clinical benefits of Levamisole therapy.     

MBIS: Multivariate Bayesian Image Segmentation tool

We present MBIS (Multivariate Bayesian Image Segmentation tool), a clustering tool based on the mixture of multivariate normal distributions model. MBIS supports multichannel bias field correction based on a B-spline model. A second methodological novelty is the inclusion of graph-cuts optimization for the stationary anisotropic hidden Markov random field model. Along with MBIS, we release an evaluation framework that contains three different experiments on multi-site data. We first validate the accuracy of segmentation and the estimated bias field for each channel. MBIS outperforms a widely used segmentation tool in a cross-comparison evaluation. The second experiment demonstrates the robustness of results on atlas-free segmentation of two image sets from scan–rescan protocols on 21 healthy subjects. Multivariate segmentation is more replicable than the monospectral counterpart on T1-weighted images. Finally, we provide a third experiment to illustrate how MBIS can be used in a large-scale study of tissue volume change with increasing age in 584 healthy subjects. This last result is meaningful as multivariate segmentation performs robustly without the need for prior knowledge.     

Computing Mimicking Networks

A mimicking network for a k -terminal network, N , is one whose realizable external flows are the same as those of N . Let S(k) denote the minimum size of a mimicking network for a k -terminal network. In this paper we give new constructions of mimicking networks and prove the following results (the values in brackets are the previously best known results): S(4)=5 [2 ¹⁶ ] , S(5)=6 [2 ³² ] . For bounded treewidth networks we show S(k)= O(k) [2^ 2 ^k ] , and for outerplanar networks we show S(k) 10k-6 [k ² 2 ^k+2 ] . Received April 1, 1997; revised December 10, 1997.     

Development of a Tool Database Management System

This paper describes a systematic approach to the design and development of a tool management system for the valve production unit of Bharat Heavy Electricals Limited (BHEL) located in Trichirapalli, India. The salient features of the design and development of a centralised database for tools that contains information regarding tooling, tool location, allo-cation, tool flow, tool storage and retrieval, parts, machines, etc. are discussed. It is estimated that the system being developed will significantly reduce the downtime of machines due to unavailability of the appropriate tools.     

On the performance characteristics of a synchronous motor fed from a voltage source inverter

Contents Using two axis model the steady state characteristics of a voltage controlled synchronous motor drive are investigated for different modes of operation based on signal flow graph technique. The input voltages are assumed to be quasi square wave. The analysis shows that depending upon the mode employed the machine can be made to possess shunt, series or mixed characteristic. The torque developed is of pulsating nature. All the modes of operation have sixth harmonic pulsations which are roughly 20 percent of the mean value. A voltage fed motor is found to have reduced torque pulsations when compared to a current fed one with the same flux levels.

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Über das Betriebsverhalten eines Synchronmotors mit Spannungszwischenkreisumrichter

Übersicht Aufgrund des Signalfußdiagramms wird das stationäre Verhalten des Spannungsgespeisten Synchronmotorantriebs bei rechteckförmiger Spannung für verschiedene Betricbsarten der Maschine untersucht. Dafür werden die Gleichungen der Maschine auf der Basis des Zweiachsenmodells aufgestellt. Die Untersuchungen zeigen, daß das Drehmoment Schwankungen hat, deren Amplitude um etwa 20 Prozent des Mittelwerts liegen. Weiter wird gezeigt, daß diese Schwankungen kleiner als die des stromgespeisten Synchronmotors sind. Je nach der Betriebsart besitzt die Maschine eine Drehmoment-Drehzahl Kennlinie, die der des Nebenschluß- oder Reihenschlußmotors ähnlich ist.

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Nomenclature i _d ,i _q direct and quadrature axis components of stator current - i _D ,i _Q direct and quadrature axis components of damper currents - l _d ,l _q synchronous inductances of direct and quadrature axes respectively - l _D ,l _Q self inductances of damper windings - l _hD ,l _hQ mutual inductances between stator and damper windings - l _hd mutual inductance between armature and field in the direct axis - L _af mutual inductance between phasea and field winding - p operator - P pairs of poles - r _a armature resistance - r _f field resistance - r _D ,r _Q damper winding resistances in the direct and quadrature axes respectively - s Laplace operator - u _d ,u _q direct and quadrature axis components of stator voltages - _d , _q direct and quadrature axis components of stator flux linkages - _D , _Q damper flux linkages in the direct and quadrature axes - _f field flux linkages - synchronous angular velocity     

Compressive property of liquid silicon (infiltrated) boron carbide

Compressive deformation of reaction bonded boron carbide has been carried out over a strain rate range 10⁻⁴ to 10⁻² s⁻¹. The maximum compressive strength of reaction bonded boron carbide at strain rate of 10⁻⁴ s⁻¹ is 370 MPa and 470 MPa at strain rate of 10⁻² s⁻¹. It is not possible to carryout quasi-static compression test at very higher strain rates (≥ 10² s⁻¹). However, the data generated at low strain rates can be extrapolated to higher strain rates and this data correlate well with the experimental compressive strength values generated by dynamic compression tests.     

Immobilized Fe(III)-HY: an efficient and stable photo-Fenton catalyst

This article presents preparation, characterization and evaluation of an efficient heterogeneous Fe(III)-HY catalyst for photo-assisted Fenton reaction. Fe(III) ions are immobilized on HY zeolite using different loadings by impregnation, calcination and the activity of the catalyst is evaluated by the degradation of phenol. To initiate a photo-Fenton reaction, suspended Fe(III)-HY in solution is irradiated using UV light to form Fe(II)-HY necessary for the reaction to go. The effect of Fe loadings, H₂O₂ concentration, pH and quenching on photo-Fenton reaction are studied. The results obtained clearly show that 0.25 wt.% Fe(III)-HY is efficient in the degradation of phenol at pH = 6. Further the efficiency of Fe(III)-HY is compared with that of a homogeneous photo-Fenton reaction and the increased rate of reaction on Fe(III)-HY highlights the synergistic role of zeolite. Heterogeneous Fe(III)-HY in photo-Fenton reaction allows a wide range of pH for reaction against the narrow pH range in homogeneous system. The system is further subjected to evaluate its stability in solid state. Firstly the reaction solution containing Fe(III)-HY catalyst on irradiation is analyzed for Fe ions with atomic absorption spectroscopy (AAS) and also by calorimetry using 1,10-phenanthroline (o-phen) to find out any Fe leaching from the catalyst and the results show insignificant leaching of Fe (<0.3 ppm) at maximum loading of Fe under experimental conditions. Secondly, the irradiated Fe(III)-HY is complexed with o-phen and it is subjected to Fourier transform infrared spectroscopy (FT-IR), diffuse reflectance spectroscopy (DRS) and electron spectroscopy for chemical analysis (ESCA) studies to detect and confirm the oxidation state of Fe in solid state. Critical analysis of these studies clearly show that Fe(III)-HY on irradiation changed to Fe(II)-HY and it is intact with the surface during the course of the reaction. The DRS spectra further evidences complexation of Fe(II) with o-phen. The stability of the catalyst is established by recycling studies.