261 research outputs found

    Comparative study for inhibitoryeffect of Benzaldehyde Derivativeson the corrosionofAl in Hydrochloric Acid:Electrochemicaland theoretical investigation.

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    The investigation carried out for inhibitory effect of p-Aminophenol-N-Benzylidene (p-AmphNB) andp-Anisidine-N-Benzylidene (p-AnsNB) for pure Aluminium 1M HClby means of standard gravimetric (weight loss), potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The values of  indicates the competitive Chemisorption and physisorption,Potentiodynamic polarization parameters revealed the mixed mode of inhibition with predominance of cathodic inhibition.The EIS showed linear correlation with concentration of inhibitor &Rctl while Cdlinversely correlated. Quantum chemical calculations based on density functional theory (DFT) method were performed on studied inhibitors. Correlation analysis concluded that the inhibition effect of inhibitors could be explained in terms of electronic properties.

    Capacidad antioxidante de cremas para galletas tipo sándwich con valor agregado a base de oleína roja de palma durante el almacenamiento

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    Red palm olein (RPOL) is naturally rich in antioxidants, yet changes in its antioxidant capacity during storage were uncertain, which limited the application of RPOL in fat-based food products. Therefore, this study incorporated shortenings composed of 0, 5, and 10% (w/w) RPOL into sandwich cookie creams of SCC-0, SCC-5, and SCC-10, respectively, and determined their antioxidant capacity during storage for six months at 20, 30, and 35 ºC. Both SCC-5 and SCC-10 exhibited higher carotene, tocopherol, tocotrienol, and total phenolic content (TPC) than that of SCC-0, yet all SCCs were comparable in their free fatty acid (FFA) and UV-total oxidation values. After six months, the SCCs exhibited low TPC and FFA, yet were high in DPPH scavenging activity. At 20 and 30 ºC, both SCC-5 and SCC-10 oxidized more slowly than that of SCC-0. These findings proved the antioxidant capacity of RPOL, which delayed oxidation reactions in the SCCs during storage.La oleína roja de palma (RPOL) es naturalmente rica en antioxidantes, pero los cambios en la capacidad antioxidante durante el almacenamiento no estaban claros y limitaron la aplicación de RPOL en productos alimenticios a base de grasas. En este estudio se incorporó mantecas compuestas por 0, 5 y 10 % (p/p) de RPOL en las cremas de galletas tipo sándwich (SCC): SCC-0, SCC-5 y SCC-10, respectivamente, y se determinó su capacidad antioxidante durante el almacenamiento durante seis meses a 20, 30 y 35 ºC. Tanto SCC-5 como SCC-10 exhibieron un mayor contenido de caroteno, tocoferol, tocotrienol y fenoles totales (TPC) que SCC-0, sin embargo, todas las SCC fueron comparables en sus valores de oxidación total de ácidos grasos libres (FFA) y UV. Después de seis meses, las SCC exhibieron TPC y FFA más bajos, pero fueron más altos en la actividad de eliminación de DPPH. A 20 y 30 ºC, tanto SCC-5 como SCC-10 se oxidaron más lentamente que SCC-0. Estos hallazgos demostraron la capacidad antioxidante de RPOL que retrasó las reacciones de oxidación en las SCC durante el almacenamiento

    Pion Freeze-Out Time in Pb+Pb Collisions at 158 A GeV/c Studied via pi-/pi+ and K-/K+ Ratios

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    The effect of the final state Coulomb interaction on particles produced in Pb+Pb collisions at 158 A GeV/c has been investigated in the WA98 experiment through the study of the pi-/pi+ and K-/K+ ratios measured as a function of transverse mass. While the ratio for kaons shows no significant transverse mass dependence, the pi-/pi+ ratio is enhanced at small transverse mass values with an enhancement that increases with centrality. A silicon pad detector located near the target is used to estimate the contribution of hyperon decays to the pi-/pi+ ratio. The comparison of results with predictions of the RQMD model in which the Coulomb interaction has been incorporated allows to place constraints on the time of the pion freeze-out.Comment: 9 pages, 12 figure

    Search for Disoriented Chiral Condensates in 158 AGeV Pb+Pb Collisions

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    The restoration of chiral symmetry and its subsequent breaking through a phase transition has been predicted to create regions of Disoriented Chiral Condensates (DCC). This phenomenon has been predicted to cause anomalous fluctuations in the relative production of charged and neutral pions in high-energy hadronic and nuclear collisions. The WA98 experiment has been used to measure charged and photon multiplicities in the central region of 158 AGeV Pb+Pb collisions at the CERN SPS. In a sample of 212646 events, no clear DCC signal can be distinguished. Using a simple DCC model, we have set a 90% C.L. upper limit on the maximum DCC production allowed by the data.Comment: 20 Pages, LaTeX, uses elsart.cls, 8 eps figures included, submitted to Physics Letters

    Evolution of the differential transverse momentum correlation function with centrality in Au+Au collisions at sNN=200\sqrt{s_{NN}} = 200 GeV

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    We present first measurements of the evolution of the differential transverse momentum correlation function, {\it C}, with collision centrality in Au+Au interactions at sNN=200\sqrt{s_{NN}} = 200 GeV. {\it C} exhibits a strong dependence on collision centrality that is qualitatively similar to that of number correlations previously reported. We use the observed longitudinal broadening of the near-side peak of {\it C} with increasing centrality to estimate the ratio of the shear viscosity to entropy density, η/s\eta/s, of the matter formed in central Au+Au interactions. We obtain an upper limit estimate of η/s\eta/s that suggests that the produced medium has a small viscosity per unit entropy.Comment: 7 pages, 4 figures, STAR paper published in Phys. Lett.

    Single Spin Asymmetry ANA_N in Polarized Proton-Proton Elastic Scattering at s=200\sqrt{s}=200 GeV

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    We report a high precision measurement of the transverse single spin asymmetry ANA_N at the center of mass energy s=200\sqrt{s}=200 GeV in elastic proton-proton scattering by the STAR experiment at RHIC. The ANA_N was measured in the four-momentum transfer squared tt range 0.003t0.0350.003 \leqslant |t| \leqslant 0.035 \GeVcSq, the region of a significant interference between the electromagnetic and hadronic scattering amplitudes. The measured values of ANA_N and its tt-dependence are consistent with a vanishing hadronic spin-flip amplitude, thus providing strong constraints on the ratio of the single spin-flip to the non-flip amplitudes. Since the hadronic amplitude is dominated by the Pomeron amplitude at this s\sqrt{s}, we conclude that this measurement addresses the question about the presence of a hadronic spin flip due to the Pomeron exchange in polarized proton-proton elastic scattering.Comment: 12 pages, 6 figure

    Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV

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    A search for a Higgs boson decaying into two photons is described. The analysis is performed using a dataset recorded by the CMS experiment at the LHC from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross section of the standard model Higgs boson decaying to two photons. The expected exclusion limit at 95% confidence level is between 1.4 and 2.4 times the standard model cross section in the mass range between 110 and 150 GeV. The analysis of the data excludes, at 95% confidence level, the standard model Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The largest excess of events above the expected standard model background is observed for a Higgs boson mass hypothesis of 124 GeV with a local significance of 3.1 sigma. The global significance of observing an excess with a local significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is estimated to be 1.8 sigma. More data are required to ascertain the origin of this excess.Comment: Submitted to Physics Letters
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