L'area delle risorgive nel sistema insediativo mesolitico: alcuni esempi dal pordenonese

The authors present the work undertaken on the lithic material collected in the spring area between Orcenico Superiore and Savorgnano (Pordenone-Italy). The sites are located on an NE-SW elongated Lateglacial gravel ridge, which to the present day is to be considered a stable area (i.e. preserved from alluvial and erosive action of Tagliamento and Meduna rivers). Different periods are represented in the lithic industries, spanning from the Mesolithic to the Bronze Age. This paper presents the results of the study carried out on the Mesolithic industries, mainly to be ascribed to the Castelnovian tradition. The typological composition of the assemblages shows different activities which could be associated with residential camps, without any particular specialization although this kind of interpretation could be biased by the non systematic nature of the findings. Different operational chains were in place, aiming to produce either bladelets or flakes. Raw materials are mostly of local origin, although few pieces were brought in from the Prealps, showing a North-South mobility along river routes. At the same time, there are scarce lithic materials imported from the upper part of the Udine plain, which is rich in good quality flint pebbles. Further technological and typological differences show a rather neat separation between sites on either sides of Tagliamento river. When we consider the distribution of Mesolithic sites in Friuli, a logistical settlement system seems to emerge: bigger sites are located at the edge of ecologically differentiated areas in connection with stable water sources such as the spring area between Orcenico and S. Vito al Tagliamento and the piedmont; complementary to those, task-related short-term sites characterised by less materials and fewer lithic types are found in the Prealps at middle altitude

Flame pyrolysis synthesis of mixed oxides for glycerol steam reforming

Flame spray pyrolysis was used to produce nanosized Ni-based catalysts starting from different mixed oxides. LaNiO3 and CeNiO3 were used as base materials and the formulation was varied by mixing them or incorporating variable amounts of ZrO2 or SrO during the synthesis. The catalysts were tested for the steam reforming of glycerol. One of the key problems for this application is the resistance to deactivation by sintering and coking, which may be increased by (1) improving Ni dispersion through the production of a Ni-La or Ni-Ce mixed oxide precursor, and then reduced; (2) using an oxide as ZrO2, which established a strong interaction with Ni and possesses high thermal resistance; (3) decreasing the surface acidity of ZrO2 through a basic promoter/support, such as La2O3; and (4) adding a promoter/support with very high oxygen mobility such as CeO2. A further key feature is the use of a high temperature synthesis, such as flame spray pyrolysis, to improve the overall thermal resistance of the oxides. These strategies proved effective to obtain active and stable catalysts at least for 20 h on stream with very limited coke formation

Ni Catalysts Supported Over TiO2, SiO2 and ZrO2 for the Steam Reforming of Glycerol

Ni-based catalysts supported on TiO2, ZrO2 and SiO2 (in the form of mesoporous Santa Barbara Amorphous 15 (SBA-15) and amorphous dense nanoparticles), were employed in the steam reforming of glycerol. Each sample was prepared by liquid phase synthesis of the support followed by impregnation with the active phase and calcination at 8008C or by direct synthesis through flame pyrolysis. Many techniques have been used to assess the physical chemical properties of both the fresh and spent catalysts, such as atomic absorption, N2 adsorption/desorption, XRD, SEM, TEM, temperature-programmed reduction (TPR), X-ray photoelectron spectroscopy (XPS), Micro-Raman and FTIR spectroscopy. The samples showed different textural, structural and morphological properties,as well as different reducibility and thermal resistance depending on the preparation method and support. Some of these properties were tightly bound to catalyst performance, in terms of H2 productivity and stability towards coking and sintering. A key parameter was the metal\u2013support interaction, which strongly depended on the preparation procedure. In particular, the stronger the interaction, the more stable the metallic Ni clusters, which in turn lead to a higher catalytic activity and stability. Surface acidity was also taken into account, in which the nature of the acid sites was differentiated (silanols, titanols or Lewis acid sites). The characterisation of the spent catalysts also allowed us to interpret the deactivation process. The formation of multi-walled nanotubes was observed for every sample, though it was only in some cases that this led to severe deactivatio

Ni Catalysts Supported Over TiO2, SiO2 and ZrO2 for the Steam Reforming of Glycerol

A 72-year-old man was admitted with one blade of a huge pair of shears in his left thorax. His hemodynamics deteriorated due to life-threatening vascular lesions. An urgent thoracotomy revealed several injuries to the intercostal vessels and left apical inferior lung lobe. The blade tip was stuck in the posterior chest wall, 2 cm adjacent to the descending aorta. The blade was removed, the lung was sutured, and the patient made a good recovery

Lo sviluppo delle conoscenze genomiche in vite e il loro potenziale utilizzo nella viticoltura attuale e futura

Nel 2007 sono stati pubblicati i risultati del sequenziamento e dell\u2019analisi dettagliata del genoma di Vitis vinifera frutto di due iniziative indipendenti, una italo-francese e l\u2019altra italo-americana. Questi risultati costituiscono la base per studi futuri e gettano le fondamenta per l\u2019adozione di metodologie innovative per sviluppare e rafforzare la viticoltura italiana e mondiale del XXI secolo. In questa review verranno illustrate le potenzialit\ue0 delle tecnologie derivate dalla conoscenza del genoma come ad esempio lo sviluppo di strumenti per l\u2019analisi di espressione genica su larga scala, e riportati alcuni esempi inerenti al loro impiego attuale e futuro in viticoltura

Effect of the support on Ni catalytic performance in glycerol steam reforming

In the last years, the use of hydrogen as new energy vector has been widely encouraged, because it is clean and carbon-free [1]. Nevertheless, an effective solution of environmental problems such as the greenhouse effect and the global warming, as well as the decrease of the dependence on fossil fuels, requires the use of renewable sources. In this context glycerol, the main by-product in biodiesel production, has emerged as a promising source of hydrogen, because of its high hydrogen content and renewability, safeness and non toxicity [2]. Several catalysts have been proposed for glycerol steam reforming. In this work we report the catalytic performances of Ni-based catalysts at two different reaction temperatures. Moreover, the effect of the support (i. e. TiO2, SBA-15 and ZrO2) on the selectivity to hydrogen was studied. TiO2 and ZrO2 were synthesized by a conventional precipitation method [3], whereas SBA15 was prepared through a template synthesis [4]. Catalysts were prepared by incipient wetness impregnation of the supports with an aqueous solution of the Ni precursor in order to obtain a 10 wt% Ni loading and they were finally calcined. The physico-chemical properties of the catalysts were determined by nitrogen physisorption analysis (BET), temperature programmed reduction (TPR) and high resolution transmission electron microscopy (HR-TEM). The activity tests were carried out in a fixed bed tubular quartz reactor at atmospheric pressure at two different temperatures (500°C and 650°C), after reduction of the samples in H2 flow for 1 hour at either 500 or 700°C respectively. A water/glycerol solution was fed (10 wt% solution of glycerol in water) at the constant flow rate of 0.06 mL/min. Data were collected up to 20 hours on each sample. The Ni/TiO2 sample exhibits negligible activity at 650°C because of the collapse of the support. Concerning Ni/SBA-15, our results indicate the insufficient hydrothermal resistance of the support, which leads to the progressive deactivation of the catalyst. However this support is able to stabilize the active phase in a rather efficient way, thus preventing Ni sintering. Ni/ZrO2 exhibits the best performances: a stable glycerol conversion of ~72% and a hydrogen yield of ~65% were obtained. This is due to the almost full preservation of the structure of the zirconia support even after 20 h in the SR conditions; moreover, also the dispersion of the Ni active phase remainedunchanged. The different behaviour of the three catalysts can be then ascribed (i) to the chemical, thermal and mechanical resistance of the support in the reaction conditions and (ii) to the intensity of the interactions between the support and the active phase, which affects in particular the stability of the Ni nanoparticles. Our results highlight the importance of the nature of the support, which plays a key role in designing the catalytic performance

The critical role of intragap states in the energy transfer from gold nanoparticles to TiO2

Cathodoluminescence spectroscopy is profitably exploited to study energy transfer mechanisms in Au and Pt/black TiO2 heterostructures. While Pt nanoparticles absorb light in the UV region, Au nanoparticles absorb light by surface plasmon resonance and interband transitions, both of them occurring in the visible region. The intra-bandgap states (oxygen vacancies) of black TiO2 play a key role in promoting both hot electron transfer and plasmonic resonant energy transfer from Au nanoparticles to the TiO2 semiconductor with a consequent photocatalytic H2 production increase. An innovative criterion is introduced for the design of plasmonic composites with increased efficiency under visible light

Grapevine field experiments reveal the contribution of genotype, the influence of environment and the effect of their interaction (GXE) on the berry transcriptome

Changes in the performance of genotypes in different environments are defined as genotype x environment (G x E) interactions. In grapevine (Vitis vinifera), complex interactions between different genotypes and cli- mate, soil and farming practices yield unique berry qualities. However, the molecular basis of this phe- nomenon remains unclear. To dissect the basis of grapevine G x E interactions we characterized berry transcriptome plasticity, the genome methylation landscape and within-genotype allelic diversity in two genotypes cultivated in three different environments over two vintages. We identified, through a novel data-mining pipeline, genes with expression profiles that were: unaffected by genotype or environment, genotype-dependent but unaffected by the environment, environmentally-dependent regardless of geno- type, and GxE-related. The GxE-related genes showed different degrees of within-cultivar allelic diversity in the two genotypes and were enriched for stress responses, signal transduction and secondary metabo- lism categories. Our study unraveled the mutual relationships between genotypic and environmental vari- ables during GxE interaction in a woody perennial species, providing a reference model to explore how cultivated fruit crops respond to diverse environments. Also, the pivotal role of vineyard location in deter- mining the performance of different varieties, by enhancing berry quality traits, was unraveled