Influence of Cobalt Doping on the Physical Properties of Zn<Subscript>0.9</Subscript>Cd<Subscript>0.1</Subscript>S Nanoparticles

Zn_0.9Cd_0.1S nanoparticles doped with 0.005–0.24 M cobalt have been prepared by co-precipitation technique in ice bath at 280 K. For the cobalt concentration >0.18 M, XRD pattern shows unidentified phases along with Zn_0.9Cd_0.1S sphalerite phase. For low cobalt concentration (≤0.05 M) particle size, d _XRD is ~3.5 nm, while for high cobalt concentration (>0.05 M) particle size decreases abruptly (~2 nm) as detected by XRD. However, TEM analysis shows the similar particle size (~3.5 nm) irrespective of the cobalt concentration. Local strain in the alloyed nanoparticles with cobalt concentration of 0.18 M increases ~46% in comparison to that of 0.05 M. Direct to indirect energy band-gap transition is obtained when cobalt concentration goes beyond 0.05 M. A red shift in energy band gap is also observed for both the cases. Nanoparticles with low cobalt concentrations were found to have paramagnetic nature with no antiferromagnetic coupling. A negative Curie–Weiss temperature of −75 K with antiferromagnetic coupling was obtained for the high cobalt concentration.     

18—TIME-DEPENDENT RECOVERY AND RELAXATION EFFECTS IN RESIN-TREATED COTTON FABRICS

Results are presented for the crease-recovery of resin-treated Oxford-weave fabrics after various loading and recovery times. Results are also given for the bending couple-relaxation and tensile stress-relaxation of these fabrics. It is shown that the differences between the crease-recoveries of moist-cure-treated and pad–dry-cure-treated fabrics may be attributed, at least in part, to the time-insensitivity of the former. It is also shown that the relaxation rates obtained by bending and extending a fabric sample are broadly similar within a reasonable range of either curvature or extension. An explanation is offered for some differences in behaviour.     

Fatigue crack growth behaviour of nickel based superalloys at ambient temperature

The present investigation deals with the study of fatigue crack growth rate (FCGR) behaviour of conventional IN 718 (Ni-0.02%C-19.0%Cr-19.35%Fe-3.0%Mo-5.10%Nb-0.50%Al-1.00%Ti-0.0033%B, all in wt%) and modified IN 718 (Ni-0.02%C-19.04%Cr-19.31%Fe-3.04%Mo-4.73%Nb-1.01%Al-1.16%Ti-0.0033%B, all in wt%) alloys at ambient temperature. Modified IN 718 alloy exhibits enhanced crack growth resistance due to roughness induced crack closure as compared to conventional IN 718 alloy.     

Experimental validation of thermal model of a double slope active solar still under natural circulation mode

In this paper, thermal modeling of a double slope active solar still has been carried out on the basis of energy balance of east and west glass covers, water mass and basin liner under natural circulation mode. The thermal model of distillation system has been validated for hourly data for inner and outer glass cover temperatures, water temperature and the yield. The hourly thermal and exergy efficiency of active solar still have also been evaluated for 0.03 m water depth. It has been observed that the thermal efficiency of double slope active solar still is lower than the thermal efficiency of double slope passive solar still. However, the exergy efficiency of double slope active solar still is higher than the exergy efficiency of double slope passive solar still. All numerical calculations have been performed for a typical day in the month of March 2008 for the composite climate of Ghaziabad (28°40′N, 77°25′E), U.P, India.     

Production of hydrogen through the coupling of dehydrogenation and hydrogenation for the synthesis of cyclohexanone and furfuryl alcohol over different promoters supported on Cu-MgO catalysts

Cu-MgO is found to be an efficient catalyst for the coupling reaction of furfural (FAL) hydrogenation and cyclohexanol (CyOH) dehydrogenation. This process is not only efficient in compensating the thermodynamic equilibrium constraints in the cyclohexanol dehydrogenation and improving the yields towards cyclohexanone but also is a economical route for the synthesis of furfuryl alcohol (FFA) and cyclohexanone (Cyone) as the process do not need any external pumping of hydrogen. The effect of incorporation of various promoters viz., Co, Zn, Fe, Cr, Pd and Ni in Cu-MgO over its activity towards this coupling reaction has been studied. Incorporation of Cr in Cu-MgO catalyst is found be an advantageous in enhancing the yields of both FFA and Cyone. All other promoters though found to show higher activity for the individual reactions of FAL hydrogenation and CyOH dehydrogenation, failed to do the same in their coupling reaction. The stabilization of active species (Cu⁺/Cu⁰) by Cr which also seem to increase the synergetic interaction between Cu and MgO as observed from higher dispersion of copper (from XRD results) and easier reducibility of copper oxide (from TPR results) seem to be the factors behind its higher activity over other promoted catalysts.     

Volume diffusion and stress corrosion cracking

The dissolution behaviour of radioactive labelled brass in cuprammonium solutions is interpreted as solid-state diffusion process. The fast rate of this process is facilitated by the large number of excess vacancies near the metal/electrolyte interface, which are generated on the corroding surface by preferential dissolution of the less noble metal. Excess vacancies are preferentially annihilated at lattice imperfections (like grain boundaries) and the voids formed decrease the tensile strength along the perturbed region. A mathematical model is developed to calculate the steady-state rates of intergranular crack propagation of homogeneous binary alloys. Results of the numerical calculations correlate closely with empirical findings in respect of the dependence from bulk alloy compositions, current densities, temperature, tensile stress, as well as threshold values for crack propagation. Basic characteristics of the mechanism are applicable for transgranular crack propagation as well as for SCC of inhomogeneous alloys.     

Preoperative sonographic diagnosis of acute appendicitis caused by Ascaris lumbricoides

Acute appendicitis caused by Ascaris lumbricoides is an uncommon variant of a common disease. We describe a case in which sonography was used for preoperative diagnosis of ascaris appendicitis.     

Protein kinase C in platelets of depressed patients

Though described in 1769, the etiology of Zenker's diverticulum remains unclear. Various primary esophageal motor disorders have been proposed, but no consistent manometric pattern or anatomic etiology has been uniformly recognized. An association with clinical neurologic disease at our institution prompted a review of 12 cases of Zenker's diverticulum in patients over 60 years of age, treated in the last 8 years. Nine patients (75%) underwent cricopharyngeus myotomy and diverticulectomy, with uniformly good results. Ten patients (83%) had an associated neurologic disorder, substantiated by cranial CT or MRI, in most cases. A wide range of neurologic problems were identified, but a strong trend toward brainstem or basilar lesions was present. As expected, the etiology of the neurologic abnormality in most patients in this group was cerebrovascular disease, but two patients had peripheral neuropathies. We suggest that the etiology of Zenker's diverticulum in the elderly may be neurologic in origin. Esophageal motor disorders, including incomplete upper esophageal sphincter opening and increased hypopharyngeal pressures, which may result in Zenker's diverticulum, may be a manifestation of central or peripheral neurologic disease in the elderly.     

Permuteins of interleukin 1{beta}--a simplified approach for the construction of permutated proteins having new termini

A technique for the rapid and simple generation of permutatedversions of the interleukin-1ß (IL-1ß) geneis described. In this method, the human IL-1ß cDNAis twice amplified by the polymerase chain reaction (PCR) andthe resulting DNA fragments are ligated in tandem. Between thetwo genes, the DNA sequence encodes a short four amino acidloop to link the native N- and C-terminal ends of the IL-1ßprotein. By using PCR amplification from this starting template,a new version of the IL-1ß cDNA was obtained thatencodes a permutated form of the IL-1ß protein wherethe new N- and C-terminal amino acids correspond to residues65 and 64 of the native IL-1ß sequence, respectively.The name ‘permutein’ is proposed to describe proteinsgenerated by this technology. The molecular profile (IL-1 receptorbinding, biologic activity and solution properties) of the IL-1permutein produced by this technology, permutein 65/64, is shownto be identical to that of native IL-1ß The approachshould be useful to define further the structural features ofthis protein that are important for its function.