The Effect of Sulphate Doping on NanosizedTiO2andMoOx/TiO2Catalysts in Cyclohexane Photooxidative Dehydrogenation

The effect of sulphate doping of titania in promoting activity and selectivity ofMoOx/TiO2catalysts for the cyclohexane photooxidative dehydrogenation has been investigated in a gas-solid fluidized bed reactor. Sulphate and/or molybdate-modified titania catalysts were prepared by incipient wet impregnation of nanosized (5–10 nm crystallite size) samples. At 60% of titania surface coverage byMoOx, sulphate surface density was obtained up to 19μmol/m2without formation ofMoO3. The catalysts were characterized byN2adsorption-desorption at−196∘C, micro-Raman and UV-visible reflectance spectroscopy, thermogravimetric analysis coupled with mass spectroscopy (TG-MS), and mass titration. Unsulphated and sulphated titania are both active in cyclohexane total oxidation, but sulphate doping of titania has a detrimental effect on the reaction rate. On Mo-based catalysts, polymolybdate species enabled sulphated titania to convert cyclohexane to benzene (99% selectivity) and cyclohexene, reducing at zero the formation ofCO2. Cyclohexane conversion to benzene is almost linearly dependent on sulphate surface density, resulting in enhanced yield to benzene. The enhanced photooxidative dehydrogenation activity and benzene yield by sulphate doping could be attributed to the increase of surface acidity and, as a consequence, of cyclohexane adsorption

Photocatalytic ethanol oxidative dehydrogenation over Pt/TiO 2: Effect of the addition of blue phosphors

Ethanol oxidative dehydrogenation over Pt/TiO 2 photocatalyst, in the presence and absence of blue phosphors, was performed. The catalyst was prepared by photodeposition of Pt on sulphated TiO 2. This material was tested in a gas-solid photocatalytic fluidized bed reactor at high illumination efficiency. The effect of the addition of blue phosphors into the fluidized bed has been evaluated. The synthesized catalysts were extensively characterized by different techniques. Pt/TiO 2 with a loading of 0.5wt of Pt appeared to be an active photocatalyst in the selective partial oxidation of ethanol to acetaldehyde improving its activity and selectivity compared to pure TiO 2. In the same way, a notable enhancement of ethanol conversion in the presence of the blue phosphors has been obtained. The blue phosphors produced an increase in the level of ethanol conversion over the Pt/TiO 2 catalyst, keeping at the same time the high selectivity to acetaldehyde. Copyright © 2012 J. J. Murcia et al.Peer Reviewe

Field emission properties of as-grown multiwalled carbon nanotube films

Multiwalled carbon nanotubes have been produced by ethylene catalytic chemical vapor deposition and used to fabricate thick and dense freestanding films ("buckypapers") by membrane filtering. Field emission properties of buckypapers have been locally studied by means of high vacuum atomic force microscopy with a standard metallic cantilever used as anode to collect electrons emitted from the sample. Buckypapers showed an interesting linear dependence in the Fowler-Nordheim plots demonstrating their suitability as emitters. By precisely tuning the tip-sample distance in the submicron region we found out that the field enhancement factor is not affected by distance variations up to 2um. Finally, the study of current stability showed that the field emission current with intensity of about 3,3*10-5A remains remarkably stable (within 5% fluctuations) for several hours.Comment: 18 pages, 5 figure

Superconducting properties of Nb thin films deposited on porous silicon templates

Porous silicon, obtained by electrochemical etching, has been used as a substrate for the growth of nanoperforated Nb thin films. The films, deposited by UHV magnetron sputtering on the porous Si substrates, inherited their structure made of holes of 5 or 10 nm diameter and of 10 to 40 nm spacing, which provide an artificial pinning structure. The superconducting properties were investigated by transport measurements performed in the presence of magnetic field for different film thickness and substrates with different interpore spacing. Perpendicular upper critical fields measurements present peculiar features such as a change in the H_c2(T) curvature and oscillations in the field dependence of the superconducting resistive transition width at H=1 Tesla. This field value is much higher than typical matching fields in perforated superconductors, as a consequence of the small interpore distance.Comment: accepted for publication on Journal of Applied Physic

Photocatalytic removal of patent blue V dye on Au-TiO2 and Pt-TiO2 catalysts

In this work it was studied the efficiency of a photocatalytic process for the removal of patent blue V. This dye is very difficult to remove by conventional treatments such as adsorption or coagulation therefore the photocatalytic process is a very interesting alternative for the removal this dye mainly because it does not require expensive oxidants and it can be carried out at mild temperatures and pressures. In this work it was tested the efficiency of Au-TiO2 and Pt-TiO2 photocatalysts in the Patent blue V removal. The Au-TiO2 catalysts were prepared by two different methods: chemical reduction and photochemical deposition; Pt-TiO2 catalysts were obtained only by photochemical deposition. In the synthesis of the catalysts prepared by photochemical deposition, it was evaluated the influence of some parameters, such as deposition time and the intensity of the light source over the physicochemical properties and photocatalytic activity of the materials obtained. An analysis of the effect of the catalyst dosage and initial patent blue V concentration over the dye degradation efficiency was also attempted. In general, it was observed that the presence of Au or Pt on TiO2 enhances the patent blue V photodegradation; it was found that noble metal particle size and distribution on TiO2 surface are important factors influencing the dye removal. The highest dye degradation was obtained over the Au-TiO2 catalyst prepared by photochemical deposition, using high light intensity and 15 min of deposition time during the synthesis. A discoloration and a total organic carbon (TOC) removal of 93 and 67% respectively, were obtained over this material after 180 min of UV irradiation. These values are higher than that the obtained on S-TiO2 (discoloration and TOC removal of about 25% and 3%, respectively)

Pre-DPF water injection technique for pressure drop control in loaded wall-flow diesel particulate filters

Wall-flow type diesel particulate filter (DPF) is a required aftertreatment system for particle emission abatement and standards fulfilment in Diesel engines. However, the DPF use involves an important flow restriction, especially as the substrate gets soot and ash loaded. It gives as a result the increase of the exhaust back-pressure and hence a fuel consumption penalty. The increasing damage of fuel consumption with DPF soot loading leads to the need of the regeneration process. Usually based on active strategies, this process involves an additional fuel penalty but prevents from excessive DPF pressure drop and ensures secure soot burnt out. Under this context, new solutions are required to improve the state of the art DPF soot loading to pressure drop ratio. This paper presents a novel technique based on pre-DPF water injection to reduce the DPF pressure drop under soot loading conditions by disrupting its dependence on soot/ash loading. It provides benefits to engine fuel economy and also higher flexibility for DPF regeneration and maintenance. The work covers a test campaign performed in a passenger car turbocharged Diesel engine equipped with a wall-flow DPF. The main objective is to describe the technique, to provide a figure of its potential for pressure drop control and fuel consumption reduction. The results of the experiments also confirm soot and ash loading capacity increase and demonstrate the lack of negative effects on filtration efficiency and active and passive regeneration.This work has been partially supported by the Spanish Ministry of Economy and Competitiveness through Grant No. TRA2013-40853-R.Bermúdez Tamarit, VR.; Serrano Cruz, JR.; Piqueras Cabrera, P.; García Afonso, Ó. (2015). Pre-DPF water injection technique for pressure drop control in loaded wall-flow diesel particulate filters. Applied Energy. 140:234-245. https://doi.org/10.1016/j.apenergy.2014.12.003S23424514

Lenalidomide Maintenance with or without Prednisone in Newly Diagnosed Myeloma Patients: A Pooled Analysis

We conducted a pooled analysis of two phase III trials, RV-MM-EMN-441 and EMN01, to compare maintenance with lenalidomide-prednisone vs. lenalidomide in newly diagnosed transplant-eligible and -ineligible myeloma patients. Primary endpoints were progression-free survival, progression-free survival 2 and overall survival with both regimens. A secondary aim was to evaluate the impact of duration of maintenance on overall survival and on outcome after relapse. A total of 625 patients (lenalidomide-prednisone arm, n = 315; lenalidomide arm, n = 310) were analyzed. The median follow-up was 58 months. Median progression-free survival (25 vs. 19 months; p = 0.08), progression-free survival 2 (56 vs. 49 months; p = 0.9) and overall survival (73 months vs. NR; p = 0.08) were not significantly different between the two arms. Toxicity profiles of lenalidomide-prednisone and lenalidomide were similar, with the exception of neutropenia that was higher in the lenalidomide arm (grade ≥ 3: 9% vs. 19%, p < 0.001), without an increase in the rate of infections. Overall survival (median NR vs. 49 months, p < 0.001), progression-free survival from relapse (median 35 vs. 24 months, p = 0.004) and overall survival from relapse (median not reached vs. 41 months, p = 0.002) were significantly longer in patients continuing maintenance for ≥2 years. We showed that the addition of prednisone at 25 or 50 mg every other day (eod) to lenalidomide maintenance did not induce any significant advantage

“Savages Who Speak French”: Folklore, Primitivism and Morals in Robert Hertz

Hertz's analysis of the Alpine cult of Saint Besse apparently marks a break from his studies of death, sin and the left to folkloric studies. This analysis helps one to understand the personality of Robert Hertz. His sociological curiosity about folklore reveals his ambiguous position in social sciences at the beginning of the twentieth century. His text appears to be a variation from the Durkheimian norm, but another reading could suggest that Hertz continued and went beyond Durkheimian thought to something between sociology of the modern world and engaged socialism. Through this study, Hertz linked his political ideals, his work in ethnology and his desire for social involvement. The cult of Saint Besse perpetuated as much religious tradition as local identity. The Alpine people were presented in the text as wilful perpetuators of an ideal social order, whose loss for his contemporary city dwellers Hertz feared. The alpine Other, marked by a material and moral backwardness, represented for activist and socialist Hertz one of the paths of balanced social organization that stabilized the identity of a group across time if it fit rather well into the folkloric stereotypes of the beginning of the twentieth century. Finally, by linking events in Herz's life (e.g., the accidental Alpine death of his father), this article suggests that the legend of Saint Besse embodied several recurring motifs in Hertz' career: the accidental deaths of saint and father by falls, the military role of the saint and of Hertz himself