1,696 research outputs found

    Analysis of the waste amount in mechanical engineering and metallurgy in Ukraine

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    Проаналізовано металургійні виробництва, які характеризуються утворенням великої кількості відходів. Більшість з них за змістом корисних компонентів конкурентоспроможні первинною сировиною та можуть бути використані в технологічних процесах. Тому доцільне розроблення системи контролю за утворенням відходів металургійних виробництв задля забезпечення використання їх у поточних виробничих процесах. Організація цього процесу дозволить вирішити екологічні проблеми, зменшити собівартість продукції, знизити споживання мінерально-сировинних ресурсів.Sammary. Different metallurgical industries, which are characterized by formation of a large amount of wastes have been analysed. Most of them within the meaning of useful components are competitive in raw materials and can be used in technological processes, so it is advisable to develop a control system for the formation of wastes of metallurgical industries to ensure their use in current manufacturing processes. The content of iron in the solid phase of secondary clarifiers sludge in metallurgical industries reaches 70%, but sludge contains 30% of water-oil content, that makes it difficult to transport, store and utilize. Typically, wastes of metallurgical and metal processing industries in percents are as follows: slag – 57 - 63; mineral wastes (scrap refractories and input components) - 4 - 6; scrap metal - 15 - 17; dust, sludge, sinter wastes - 9 - 13; others - 2 - 4. Thus, for example, specific output of sludge in productions of Ukraine is 60-80 kg/t of steel, in Europe this index is 30 kg/t. Metallurgical enterprises of Ukraine have accumulated 240 million tons of slag, 128 million tons of which are steel-smelting. A significant amount of sludge in wastes of metallurgical and metal processing industries contain from 45% to 52% of iron, 6,0-9,5% of carbon with a small amount of zinc (0,5-4%). This raw material can be used in the agglomeration and in converter steel production. However, 90% of wastes after various metallurgical processes are put together in same sludge storages where they are stored. A storage of sludge, steel and metal processing wastes of productions leads to the fact that richer for the mass fraction of iron sludge depletes due a contact with less rich with iron sludge. Another disadvantage is environmental. The paradox of the situation is that we create a man-made iron-containing materials, in which the mass fraction of iron exceeds its concentration in the rich iron ore which we take from the depths (56-60%), and glandular concentrates which we get on concentrators (65-68%). Organization of the process of waste monitoring will solve environmental problems, reduce production costs, reduce the consumption of mineral-raw resources

    First observation of a narrow charm-strange meson DsJ(2632) -> Ds eta and D0 K+

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    We report the first observation of a charm-strange meson DsJ(2632) at a mass of 2632.6+/-1.6 MeV/c^2 in data from SELEX, the charm hadro-production experiment E781 at Fermilab. This state is seen in two decay modes, Ds eta and D0 K+. In the Ds eta decay mode we observe an excess of 49.3 events with a significance of 7.2sigma at a mass of 2635.9+/-2.9 MeV/c^2. There is a corresponding peak of 14 events with a significance of 5.3sigma at 2631.5+/-1.9 MeV/c^2 in the decay mode D0 K+. The decay width of this state is <17 MeV/c^2 at 90% confidence level. The relative branching ratio Gamma(D0K+)/Gamma(Dseta) is 0.16+/-0.06. The mechanism which keeps this state narrow is unclear. Its decay pattern is also unusual, being dominated by the Ds eta decay mode.Comment: 5 pages, 3 included eps figures. v2 as accepted for publication by PR

    First Measurement of pi e -> pi e gamma Pion Virtual Compton Scattering

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    Pion Virtual Compton Scattering (VCS) via the reaction pi e --> pi e gamma was observed in the Fermilab E781 SELEX experiment. SELEX used a 600 GeV/c pi- beam incident on target atomic electrons, detecting the incident pi- and the final state pi-, electron and gamma. Theoretical predictions based on chiral perturbation theory are incorporated into a Monte Carlo simulation of the experiment and are compared to the data. The number of reconstructed events (9) and their distribution with respect to the kinematic variables (for the kinematic region studied) are in reasonable accord with the predictions. The corresponding pi- VCS experimental cross section is sigma=38.8+-13 nb, in agreement with the theoretical expectation sigma=34.7 nb.Comment: 10 pages, 12 figures, 4 tables, 25 references, SELEX home page is http://fn781a.fnal.gov/, revised July 21, 2002 in response to journal referee Comment

    Observation of the Cabibbo-suppressed decay Xi_c+ -> p K- pi+

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    We report the first observation of the Cabibbo-suppressed charm baryon decay Xi_c+ -> p K- pi+. We observe 150 +- 22 events for the signal. The data were accumulated using the SELEX spectrometer during the 1996-1997 fixed target run at Fermilab, chiefly from a 600 GeV/c Sigma- beam. The branching fractions of the decay relative to the Cabibbo-favored Xi_c+ -> Sigma+ K- pi+ and Xi_c+ -> X- pi+ pi+ are measured to be B(Xi_c+ -> p K- pi+)/B(Xi_c+ -> Sigma+ K- pi+) = 0.22 +- 0.06 +- 0.03 and B(Xi_c+ -> p K- pi+)/B(Xi_c+ -> X- pi+ pi+) = 0.20 +- 0.04 +- 0.02, respectively.Comment: 5 pages, RevTeX, 3 figures (postscript), Submitted to Phys. Rev. Let

    First Observation of the Doubly Charmed Baryon Xi_cc^+

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    We observe a signal for the doubly charmed baryon Xi_cc^+ in the charged decay mode Xi_cc^+ --> Lambda_c^+ K- pi+ in data from SELEX, the charm hadro-production experiment at Fermilab. We observe an excess of 15.9 events over an expected background of 6.1 +/- 0.5 events, a statistical significance of 6.3sigma. The observed mass of this state is (3519 +/- 1) MeV/c^2. The Gaussian mass width of this state is 3MeV/c^2, consistent with resolution; its lifetime is less than 33fsec at 90% confidence.Comment: 5 pages, 3 figures, accepted for publication in Physical Review Letter

    Confirmation of the Double Charm Baryon Xi_cc+ via its Decay to p D+ K-

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    We observes a signal for the double charm baryon Xi_cc+ in the charged decay mode Xi_cc+ -> p D+ K- to complement the previously reported decay Xi_cc+ -> Lambda_c K- pi+ in data from SELEX, the charm hadro-production experiment (E781) at Fermilab. In this new decay mode we observe an excess of 5.62 events over an expected background estimated by event mixing to be 1.38+/-0.13 events. The Poisson probability that a background fluctuation can produce the apparent signal is less than 6.4E-4. The observed mass of this state is (3518+/-3)MeV/c^2, consistent with the published result. Averaging the two results gives a mass of (3518.7+/-1.7)MeV/c^2. The observation of this new weak decay mode confirms the previous SELEX suggestion that this state is a double charm baryon. The relative branching ratio Gamma(Xi_cc+ -> pD+K-)/Gamma(Xi_cc+ -> Lambda_c K- pi+) = 0.36+/-0.21.Comment: 11 pages, 6 included eps figures. v2 includes improved statistical method to determine significance of observation. Submitted to PL

    Measurement of the Ds lifetime

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    We report precise measurement of the Ds meson lifetime. The data were taken by the SELEX experiment (E781) spectrometer using 600 GeV/c Sigma-, pi- and p beams. The measurement has been done using 918 reconstructed Ds. The lifetime of the Ds is measured to be 472.5 +- 17.2 +- 6.6 fs, using K*(892)0K+- and phi pi+- decay modes. The lifetime ratio of Ds to D0 is 1.145+-0.049.Comment: 5 pages, 2 figures submitted to Phys. Lett.
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