124 research outputs found

    HIGH-FREQUENCY TITRATION AS APPLIED TO THE DETERMINATION OF THORIUM, URANIUM, SULFATE, AND FREE ACID. PARTS I-V

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    The technique of high-frequency titrimetry was applied to the determination of thorium, uranium, sulfate, and free acid. In Part I, the reproducibility of the method for the titration of standard solutions that contained 50 rag of thorium in the absence of interferences is established. Under these conditions, the coefficient of variation of the method was <1%. In Part II, the effect of uranium on the highfrequency titration of thorium, as well as the application of the method to actual samples, is discussed. Uranium in a ratio of 5 to 1 to thorium can be tolerated. When the method is applied to the analysis of representative samples, the coefficient of variation is 1%. Attempts to determine uranium by high-frequency titration with 8-quinolinol were unsuccessful. Tests on this titration and possible reasons for its failure are discussed in Part III. The application of the high-frequency titration method to the determination of sulfate in solutions of uranyl sulfate is described in Part IV. The coefficient of variation, on titrating 40 to 70 mg of sulfate with barium chloride after the uranium is masked with citrate or fluoride, is 2%. In Part V, the high-frequency titration of free acid in solutions of uranyl sulfate is dis cussed. Uranium up to 350 mg, which was the highest level tested, does not interfere. The coefficient of variation of the method is -2%. (auth

    THE REMOVAL OF CORROSION SCALE FROM HEAT EXCHANGER BY CHEMICAL TREATMENTS

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    disintegrating a corrosion scale from stainless steel systems without attacking the stainless steel. In this investigation particular sample of stainless steel corrosion scale appeared to be disintegrated most effectively in a solution of the trisodium salt of N-hydroxyethylethylenediaminetriacetic acid (Versenol) and ammonium acetate. In a subsequent test with this solution in a REED dynamic Ioop a considerable disintegration of scale from the loop was observed. in this test after a period of approximately 60 hours, the iron content in the solution was found to be 10 g per liter; thus indicating that the mixture of Versenol and ammonium acetate can be used to disintegrate partially the corrosion scale from a stainless steel system. (auth

    HIGH-PRECISION DETERMINATIONS BY MEANS OF HIGH-ABSORBANCY SPECTRO- PHOTOMETRIC METHOD. APPLICATION TO THE DETERMINATION OF COBALT IN ALUMINUM

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    High-absorbancy spectrophotometry was applied to the precise determination of about 0.15% cobalt in aluminum by the 1-(2-pyridylazo)-2- naphthol method. The absorbancies of sample aliquots were measured versus a standard containing 50 mu g of cobalt. The relative concentration error for a single measurement, assuming a 1% transmittancy error, is 0.93% and the coefficient of variation of 5 cobalt determinations is 0.5%. (auth

    On the absence of bound-state stabilization through short ultra-intense fields

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    We address the question of whether atomic bound states begin to stabilize in the short ultra-intense field limit. We provide a general theory of ionization probability and investigate its gauge invariance. For a wide range of potentials we find an upper and lower bound by non-perturbative methods, which clearly exclude the possibility that the ultra intense field might have a stabilizing effect on the atom. For short pulses we find almost complete ionization as the field strength increases.Comment: 34 pages Late

    On the Influence of Pulse Shapes on Ionization Probability

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    We investigate analytical expressions for the upper and lower bounds for the ionization probability through ultra-intense shortly pulsed laser radiation. We take several different pulse shapes into account, including in particular those with a smooth adiabatic turn-on and turn-off. For all situations for which our bounds are applicable we do not find any evidence for bound-state stabilization.Comment: 21 pages LateX, 10 figure

    Ionization Probabilities through ultra-intense Fields in the extreme Limit

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    We continue our investigation concerning the question of whether atomic bound states begin to stabilize in the ultra-intense field limit. The pulses considered are essentially arbitrary, but we distinguish between three situations. First the total classical momentum transfer is non-vanishing, second not both the total classical momentum transfer and the total classical displacement are vanishing together with the requirement that the potential has a finite number of bound states and third both the total classical momentum transfer and the total classical displacement are vanishing. For the first two cases we rigorously prove, that the ionization probability tends to one when the amplitude of the pulse tends to infinity and the pulse shape remains fixed. In the third case the limit is strictly smaller than one. This case is also related to the high frequency limit considered by Gavrila et al.Comment: 16 pages LateX, 2 figure

    Elliptic flow of charged particles in Pb-Pb collisions at 2.76 TeV

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    We report the first measurement of charged particle elliptic flow in Pb-Pb collisions at 2.76 TeV with the ALICE detector at the CERN Large Hadron Collider. The measurement is performed in the central pseudorapidity region (|η\eta|<0.8) and transverse momentum range 0.2< pTp_{\rm T}< 5.0 GeV/cc. The elliptic flow signal v2_2, measured using the 4-particle correlation method, averaged over transverse momentum and pseudorapidity is 0.087 ±\pm 0.002 (stat) ±\pm 0.004 (syst) in the 40-50% centrality class. The differential elliptic flow v2(pT)_2(p_{\rm T}) reaches a maximum of 0.2 near pTp_{\rm T} = 3 GeV/cc. Compared to RHIC Au-Au collisions at 200 GeV, the elliptic flow increases by about 30%. Some hydrodynamic model predictions which include viscous corrections are in agreement with the observed increase.Comment: 10 pages, 4 captioned figures, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/389

    A randomized open-label phase III trial evaluating the addition of denosumab to standard first-line treatment in advanced NSCLC : the European Thoracic Oncology Platform (ETOP) and European Organisation for Research and Treatment of Cancer (EORTC) SPLENDOUR trial

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    Introduction Receptor activator of NF-kB ligand stimulates NF-kB–dependent cell signaling and acts as the primary signal for bone resorption. Retrospective analysis of a large trial comparing denosumab versus zoledronic acid in bone metastatic solid tumors suggested significant overall survival (OS) advantage for patients with lung cancer with denosumab (p = 0.01). The randomized open-label phase III SPLENDOUR trial was designed to evaluate whether the addition of denosumab to standard first-line platinum-based doublet chemotherapy improved OS in advanced NSCLC. Methods Patients with stage IV NSCLC were randomized in a 1:1 ratio to either chemotherapy with or without denosumab (120 mg every 3–4 wks), stratified by the presence of bone metastases (at diagnosis), Eastern Cooperative Oncology Group performance status, histology, and region. To detect an OS increase from 9 to 11.25 months (hazard ratio [HR] = 0.80), 847 OS events were required. The trial closed prematurely owing to decreasing accrual rate. Results A total of 514 patients were randomized, with 509 receiving one or more doses of the assigned treatment (chemotherapy: 252, chemotherapy-denosumab: 257). The median age was 66.1 years, 71% were men, and 59% were former smokers. Bone metastases were identified in 275 patients (53%). Median OS (95% confidence interval [CI]) was 8.7 (7.6–11.0) months in the control arm versus 8.2 (7.5–10.4) months in the chemotherapy-denosumab arm (HR = 0.96; 95% CI: 0.78–1.19; one-sided p = 0.36). For patients with bone metastasis, HR was 1.02 (95% CI: 0.77–1.35), whereas for those without, HR was 0.90 (95% CI: 0.66–1.23). Adverse events grade 3 or greater were observed in 40.9%, 5.2%, 8.7% versus 45.5%, 10.9%, 10.5% of patients. Conditional power for OS benefit was less than or equal to 10%. Conclusions Denosumab was well-tolerated without unexpected safety concerns. There was no OS improvement for denosumab when added to chemotherapy in the intention-to-treat population and the subgroups with and without bone metastases. Our data do not provide evidence of a clinical benefit for denosumab in patients with NSCLC without bone metastases

    FLAME PHOTOMETRIC DETERMINATION OF IRON. PARTS I, II, III AND IV

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    An investigation was conducted to compare the flame emission spectrum of Fe as recorded by the Beckman DU and the ORNL flame spectrophotometers. It was found that the ORNL instrument is best suited to the application. Optimum operating conditions are described as well as results of investigations to determine interferences. (J.R.D.
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