Aluminum 7075 based composites reinforced with alumina (Al2O3) in varying particle size of 100,140 and 200 mesh(149,105 ,74 micron) & varying reinforcement weight fractions of 3%,6%,9% and 12% were prepared. The stir casting process was chosen as the manufacturing route as it is cost effective for mass production. Stirring of the melt was carried out to achieve uniform distribution of the reinforcement Mechanical test like Hardness test, Microstructure characterization and wear study was conducted on the casted composites to know the effect of particle size and weight fraction of reinforcement. Hardness was found to increase with decrease in particle size and it increases as the weight fraction increases. The wear rate and coefficient of friction decreased as the particle size was reduced. But increase in weight fraction reduces both wear rate and coefficient of friction.

BACKGROUND, Drug-eluting stents have enabled considerable reduction in restenosis in patients subjected to angioplasty. However, in view of high cost of drug-eluting stents, efforts to develop medicated stents at reduced cost using alternative polymers in Indian setting are imperative. Hence a multi-center study was undertaken to evaluate the safety and efficacy of the indigenously developed paclitaxel-eluting RELEASE-T stent. METHODS, The study included 100 patients (male:86, Female:14) who were undergoing angioplasty for various indications at four centres viz. Delhi, Hyderabad, Pune and Warangal. The age range was 29 - 76 years; 37 patients were diabetic. All patients were pre-treated with aspirin 150-325 mg plus clopidogrel 75 mg daily four days before procedure or clopidogrel alone. Aspirin was continued indefinitely. RESULTS, Direct stenting ws done in majority of patients. One patient, in whom stent could not be delivered, received only baloon angioplasty. Sixty-four patients had stenting of left anterior descending artery. The stent diameter ranged from 2.5 to 3.5 mm, and the length, 15 to 20 mm. All patients were followed up at 1,3 and 6 months. There was two deaths: one had subacute thrombosis on both stents, and the other (who was HIV positive) had sudden cardiac death. The 6-month rate of major adverse cardiac events was 4% and target lesion revascularization rate ws 2%. CONCLUSION, This ulti-locational study brings out that the use of indigenously developed paclitaxel-eluting stent is safe and clinically efficacious.

A measurement of direct photon production in Pb-208+Pb-208 collisions at 158 A GeV has been carried out in the CERN WA98 experiment. Invariant yield of direct photons was extracted as a function of transverse momentum in the interval 0.5 < P-T < 3.3 GeV/c for peripheral, and 0.5 < P-T < 4.0 GeV/c for central collisions. Direct photon yield was extracted on a statistical basis as the difference between the measured inclusive spectrum of photons, and the calculated spectrum of photons which result from all hadrons with significant radiative decay contributions. While no direct photon excess was observed for the peripheral event sample, a significant direct photon signal, compared to statistical and systematical errors, was seen in central collisions at P-T > 1.5 GeV/c. The result constitutes the first observation of direct photons in ultrarelativistic heavy-ion collisions.

Antimony cluster thin films have been synthesized by the newly-developed low energy cluster beam deposition technique. Proton-induced X-ray emission analysis shows absence of any foreign impurity even at ppm level. Structural analysis by glancing angle X-ray diffraction indicates presence of rhombohedral Sb along with Sb-oxides. Transmission electron microscopy micrographs for 20 Angstrom and 100 Angstrom films respectively show the size distribution along with isolated aggregates. The size distribution for 100 Angstrom thick film is found to be large compared to the 20 Angstrom one. Transmission electron diffraction studies reveal hexagonal symmetry.

Results from the multiplicity distributions of inclusive photons and charged particles, scaling of particle multiplicities, event-by-event multiplicity fluctuations, and charged-neutral fluctuations in 158A GeV Pb+Pb collisions are presented and discussed. A scaling of charged particle multiplicity as N part 1.07±0.05 and photos as N part 1.12±0.03 have been observed, indicating violation of naive wounded nucleon model. The analysis of localized charged-neutral fluctuation indicates a model-independent demonstration of non-statistical fluctuations in both charged particles and photons in limited azimuthal regions. However, no correlated charged-neutral fluctuations are observed.

Localized fluctuations in the multiplicity of charged particles and photons produced in central 158A GeV/c Pb+Pb collisions are studied. The charged versus neutral correlations in common eta-phi phase space regions of varying azimuthal size are analyzed by two different methods. The analysis provides a model-independent demonstration of nonstatistical fluctuations in both charged particle and photon multiplicities in limited azimuthal regions. However, no correlated charge-neutral fluctuations are observed, contrary to expectations for the production of a disoriented chiral condensate. The result is not explained by the widely used VENUS model.

The Delta(++)-resonance production in central 158 A GeV Pb-208 + Pb-208 collisions at the CERN SPS has been studied. The Delta(++) production was estimated from the invariant mass spectrum of p pi(+)-pairs by subtracting a mixed event background. The measured Delta(++) abundance is compared with the results from other experiments at lower energies, and with a model calculation assuming thermal and chemical equilibrium. (C) 2000 Elsevier Science B.V. All rights reserved.

M. M. Aggarwal,1 A. Agnihotri,2 Z. Ahammed,3 A. L. S. Angelis,4 V. Antonenko,5 V. Arefiev,6 V. Astakhov,6 V. Avdeitchikov,6 T. C. Awes,7 P. V. K. S. Baba,8 S. K. Badyal,8 C. Barlag,9 S. Bathe,9 B. Batiounia,6 T. Bernier,10 K. B. Bhalla,2 V. S. Bhatia,1 C. Blume,9 R. Bock,11 E.-M. Bohne,9 Z. Böröcz,9 D. Bucher,9 A. Buijs,12 H. Büsching,9 L. Carlen,13 V. Chalyshev,6 S. Chattopadhyay,3 R. Cherbatchev,5 T. Chujo,14 A. Claussen,9 A. C. Das,3 M. P. Decowski,18 H. Delagrange,10 V. Djordjadze,6 P. Donni,4 I. Doubovik,5 S. Dutt,8 M. R. Dutta Majumdar,3 K. El Chenawi,13 S. Eliseev,15 K. Enosawa,14 P. Foka,4 S. Fokin,5 M. S. Ganti,3 S. Garpman,13 O. Gavrishchuk,6 F. J. M. Geurts,12 T. K. Ghosh,16 R. Glasow,9 S. K. Gupta,2 B. Guskov,6 H. Å. Gustafsson,13 H. H. Gutbrod,10 R. Higuchi,14 I. Hrivnacova,15 M. Ippolitov,5 H. Kalechofsky,4 R. Kamermans,12 K.-H. Kampert,9 K. Karadjev,5 K. Karpio,17 S. Kato,14 S. Kees,9 C. Klein-Bösing,9 S. Knoche,9 B. W. Kolb,11 I. Kosarev,6 I. Koutcheryaev,5 T. Krümpel,9 A. Kugler,15 P. Kulinich,18 M. Kurata,14 K. Kurita,14 N. Kuzmin,6 I. Langbein,11 A. Lebedev,5 Y. Y. Lee,11 H. Löhner,16 L. Luquin,10 D. P. Mahapatra,19 V. Manko,5 M. Martin,4 G. Martínez,10 A. Maximov,6 G. Mgebrichvili,5 Y. Miake,14 Md. F. Mir,8 G. C. Mishra,19 Y. Miyamoto,14 B. Mohanty,19 M.-J. Mora,10 D. Morrison,20 D. S. Mukhopadhyay,3 H. Naef,4 B. K. Nandi,19 S. K. Nayak,10 T. K. Nayak,3 S. Neumaier,11 A. Nianine,5 V. Nikitine,6 S. Nikolaev,5 P. Nilsson,13 S. Nishimura,14 P. Nomokonov,6 J. Nystrand,13 F. E. Obenshain,20 A. Oskarsson,13 I. Otterlund,13 M. Pachr,15 S. Pavliouk,6 T. Peitzmann,9 V. Petracek,15 W. Pinganaud,10 F. Plasil,7 U. v. Poblotzki,9 M. L. Purschke,11 J. Rak,15 R. Raniwala,2 S. Raniwala,2 V. S. Ramamurthy,19 N. K. Rao,8 F. Retiere,10 K. Reygers,9 G. Roland,18 L. Rosselet,4 I. Roufanov,6 C. Roy,10 J. M. Rubio,4 H. Sako,14 S. S. Sambyal,8 R. Santo,9 S. Sato,14 H. Schlagheck,9 H.-R. Schmidt,11 Y. Schutz,10 G. Shabratova,6 T. H. Shah,8 I. Sibiriak,5 T. Siemiarczuk,17 D. Silvermyr,13 B. C. Sinha,3 N. Slavine,6 K. Söderström,13 N. Solomey,4 G. Sood,1 S. P. Sørensen,7,20 P. Stankus,7 G. Stefanek,17 P. Steinberg,18 E. Stenlund,13 D. Stüken,9 M. Sumbera,15 T. Svensson,13 M. D. Trivedi,3 A. Tsvetkov,5 L. Tykarski,17 J. Urbahn,11 E. C. v. d. Pijll,12 N. v. Eijndhoven,12 G. J. v. Nieuwenhuizen,18 A. Vinogradov,5 Y. P. Viyogi,3 A. Vodopianov,6 S. Vörös,4 B. Wysłouch,18 K. Yagi,14 Y. Yokota,14 and G. R. Young7

The preliminary results of anisotropic transverse flow will be reported in 158 A GeV Pb + Pb collisions.The centrality dependence of the directed flow has been measured at the target rapidity region. The directed flow of the pions is opposite to that of the protons, where the magnitude of the directed flow of protons seem to be significantly smaller than observed at AGS energies and than RQMD. While, maximum directed flow is observed in more peripheral events. Near mid-rapidity region, the elliptic flow of pi(+/-) mesons is studied. The shape of the two-pion correlation function is investigated as a function of the two-particle emission angle relative to the target proton flow. Our preliminary results show an indication of a dependence of the two-pion correlation function on the direction of emission relative to the target flow direction for semi-central collisions.

Three-particle correlations have been measured for identified pi(-) from central 158A GeV Pb+Pb collisions by the WA98 experiment at CERN. A substantial contribution of the genuine three-body correlation has been found as expected for a mainly chaotic and symmetric source.

The design and fabrication of a Smalley-type cluster source in combination with a reflectron based time-of-flight (TOF) mass spectrometer are reported. The generation of clusters is based on supersonic jet expansion of the sampling plume. Sample cells for both liquid and solid targets developed for this purpose are described. Two pulsed Nd-YAG lasers are used in tandem, one (532 nm) for target vapourization and the other (355 nm) for cluster ionization. Methanol clusters of nuclearity up to 14 (mass 500 amu) were produced from liquid methanol as the test sample. The clusters were detected with a mass resolution of ∼ 2500 in the R-TOF geometry. Carbon clusters up to a nuclearity of 28 were obtained using a polyimide target. The utility of the instrument is demonstrated by carrying out experiments to generate mixed clusters from alcohol mixtures.