Experimental and theoretical studies of (E)-N′-1-(4-propylbenzylidene)nicotinohydrazide as corrosion inhibitor of mild steel in 1 M HCl

The efficiency of a novel Schiff base namely (E)-N′-1-(4-propylbenzylidene)nicotinohydrazide (PBNH) was investigated as corrosion inhibitor of mild steel (MS) in 1M HCl using weight loss technique at 303 and 313 K. It was established that corrosion rate of mild steel increases with increase in temperature and concentration of HCl. Results showed that PBNH considerably inhibited the corrosion of mild steel in a 1 M HCl solution and inhibition efficiency is about 70% at 4 × 10−4 M PBNH at both temperatures. The inhibition efficiency of PBNH increased with an increase in concentration and temperature. The adsorption model obeys the Langmuir adsorption isotherm and the kinetic-thermodynamic model and the value of free energy of adsorption, ΔGads indicated that the adsorption of PBNH was a spontaneous process and was both an electrostatic-adsorption (physisorption) and adsorption on the basis of donor-acceptor interactions (chemisorption). Thermodynamic parameters calculated show the spontaneity and endothermic nature of the process and also reveal the favourable affinity of PBNH towards the mild steel surface. Quantum chemical calculations based on PM3 method was performed on PBNH and calculated parameters gave useful information to explain the interaction between the surface of metal and PBN

Wave Mechanics and General Relativity: A Rapprochement

Using exact solutions, we show that it is in principle possible to regard waves and particles as representations of the same underlying geometry, thereby resolving the problem of wave-particle duality

Radiative Tau Lepton Pair Production as a Probe of Anomalous Electromagnetic Couplings of the Tau

We calculate the squared matrix element for the process e+ e- --> tau+ tau- gamma allowing for anomalous magnetic and electric dipole moments at the tau tau gamma vertex. No interferences are neglected and no approximations of light fermion masses are made. We show that anomalous moments affect not only the cross section, but also the shape of the photon energy and angular distributions. We also demonstrate that in the case of the anomalous magnetic dipole moment, the contribution from interference involving Standard Model and anomalous amplitudes is significant compared to the contribution from anomalous amplitudes alone. A program to perform the calculation is available and it may be employed as a Monte Carlo generator.Comment: 14 pages, 8 figures submitted to Nuclear Physics

Hard thermal loops and the entropy of supersymmetric Yang-Mills theories

We apply the previously proposed scheme of approximately self-consistent hard-thermal-loop resummations in the entropy of high-temperature QCD to N=4 supersymmetric Yang-Mills (SYM) theories and compare with a (uniquely determined) R[4,4] Pad\'e approximant that interpolates accurately between the known perturbative result and the next-to-leading order strong-coupling result obtained from AdS/CFT correspondence. We find good agreement up to couplings where the entropy has dropped to about 85% of the Stefan-Boltzmann value. This is precisely the regime which in purely gluonic QCD corresponds to temperatures above 2.5 times the deconfinement temperature and for which this method of hard-thermal-loop resummation has given similar good agreement with lattice QCD results. This suggests that in this regime the entropy of both QCD and N=4 SYM is dominated by effectively weakly coupled hard-thermal-loop quasiparticle degrees of freedom. In N=4 SYM, strong-coupling contributions to the thermodynamic potential take over when the entropy drops below 85% of the Stefan-Boltzmann value.Comment: 14 pages, 2 figures, JHEP3. v2: revised and expanded, with unchanged HTL results but corrected NLO strong-coupling result from AdS/CFT (which is incorrectly reproduced in almost all previous papers comparing weak and strong coupling results of N=4 SYM) and novel (unique) Pade approximant interpolating between weak and strong coupling result

Anisotropic low field behavior and the observation of flux jumps in CeCoIn5

The magnetic behavior of the heavy fermion superconductor CeCoIn5 has been investigated. The low field magnetization data show flux jumps in the mixed state of the superconducting phase in a restricted range of temperature. These flux jumps begin to disappear below 1.7 K, and are completely absent at 1.5 K. The magnetization loops are asymmetric, suggesting that surface and geometrical factors dominate the pinning in this system. The lower critical field (Hc1), obtained from the magnetization data, shows a linear temperature dependence and is anisotropic. The calculated penetration depth is also anisotropic, which is consistent with the observation of an anisotropic superconducting gap in CeCoIn5. The critical currents, determined from the high field isothermal magnetization loops, are comparatively low (around 4000 A/cm2 at 1.6 K and 5 kOe).Comment: 4 pages 3 figure

Experimental and Theoretical Studies of (E)-N'-1-(4- propylbenzylidene)nicotinohydrazide as Corrosion Inhibitor of Mild Steel in 1 M HC

The efficiency of a novel Schiff base namely (E)-N'-1-(4-propylbenzylidene)nicotinohydrazide (PBNH) was investigated as corrosion inhibitor of mild steel (MS) in 1M HCl using weight loss technique at 303 and 313 K. It was established that corrosion rate of mild steel increases with increase in temperature and concentration of HCl. Results showed that PBNH considerably inhibited the corrosion of mild steel in a 1 M HCl solution and inhibition efficiency is about 70% at 4 × 10–4 M PBNH at both temperatures. The inhibi� tion efficiency of PBNH increased with an increase in concentration and temperature. The adsorption model obeys the Langmuir adsorption isotherm and the kinetic–thermodynamic model and the value of free energy of adsorption, indicated that the adsorption of PBNH was a spontaneous process and was both an elec� trostatic�adsorption (physisorption) and adsorption on the basis of donor�acceptor interactions (chemisorp�tion). Thermodynamic parameters calculated show the spontaneity and endothermic nature of the process and also reveal the favourable affinity of PBNH towards the mild steel surface. Quantum chemical calcula�tions based on PM3 method was performed on PBNH and calculated parameters gave useful information to explain the interaction between the surface of metal and PBNH

Waste-derived activated carbons for control of nitrogen oxides

Activated carbons were produced from waste and investigated for their efficiency for the removal of mono-nitrogen oxides (NOx) in simulated flue gases at a low temperature. The wastes used were waste biomass (date seeds), processed municipal solid waste in the form of refuse-derived fuel and waste tyres. The morphology, porous texture and surface chemistry of the prepared activated carbons were evaluated by scanning electron microscopy, energy-dispersive X-ray spectrometry, nitrogen adsorption and Boehm titration, and were compared with several commercial activated carbons. The carbons were then investigated in terms of their use in adsorbing NOx at a low temperature. The waste-derived activated carbons had NOx adsorption efficiencies at 50°C which were between 50 and 70% of those achieved for the commercial activated carbons. Increasing the adsorption temperature from 25 to 100°C significantly reduced nitrogen oxide (NO) adsorption. It was also shown that the NO adsorption efficiency depends on the porous structure, particularly the presence of micropores in the activated carbon, but to a lesser extent on the surface area of the carbons and acid–base surface groups on the carbon surface

Canterbury index : an accurate predictor of fracture re-displacement?

PURPOSE: Paediatric forearm fractures are commonly seen and treated by closed reduction and plaster cast application in theatre. Historically cast application has been subjectively evaluated for its adequacy in maintaining fracture reduction. More recently emphasis has been placed on objectively evaluating the adequacy of cast application using indicators such as the Canterbury index (CI). The CI has been used in predicting post-reduction, re-displacement risk of patients by expressing the cast and padding indexes as a ratio. The CI has been criticised for not including cast three-point pressure, fracture personality, lack of standardisation of X-ray views as well as practical requirement of physical measurement using rulers. The aim of this study was to determine whether subjective evaluation of these indices, before and after a tutorial on the CI, was accurate in predicting a patient’s ultimate risk of re-displacement, following reduction and casting. In addition, we aimed to determine whether objective evaluation of these indices by measurement on the hospital’s digital X-ray system correlated with the final fracture outcome post-reduction. MATERIALS AND METHODS: A retrospective study was done on a sample of 11 patients during the period May 2010 to July 2011 at Steve Biko Academic Hospital. In total, 44 X-rays/fluoroscopy views were subjectively evaluated by 20 registrars and eight consultants for possible fracture re-displacement, before and after a tutorial on the CI. Five consultants and 10 registrars each measured 22 cast, padding and CIs on the digital X-ray system. RESULTS: A formal tutorial did not produce an increase in subjective predictive accuracy. Pre- and post-tutorial observed agreement was seldom better than agreement by chance alone. Poor strength of agreement (κ <0.20) was found in all groups, irrespective of level of displacement, imaging modality, level of orthopaedic training and tutorial attendance. Objective measurement of the indexes all had insignificant p-values for comparing groups, indicating that there was no correlation between the measured indexes and the final outcome irrespective of the level of fracture, imaging modality and level of orthopaedic training. Shortcomings were variable co-operation from participants and non-standardisation of X-rays. CONCLUSION: In our hospital setting, no clinical value for the subjective and/or objective use of the CI could be found. Subjective agreement was almost the same as expected agreement and objective measurement indicated no correlation with the fracture outcome. It is suggested that patients following closed reduction of forearm fractures be followed up within the first three days, and regularly thereafter, as there is currently no ideal system to predict re-displacement. Further studies are needed to validate the CI by standardisation of X-rays.http://www.charpublications.co.za/C_JournalsORTH.as