130,805 research outputs found
Tomographic 2-D X-ray imaging of toroidal fusion plasma using a tangential pinhole camera with gas electron multiplier detector
No full textA tangential X-ray pinhole camera based on a gas electron multiplier (GEM) detector was installed on KSTAR to study high temperature plasmas emitting X-ray photons in the energy band of 4–15 keV. The camera system consists of a triple-GEM gas chamber with a readout printed circuit board and a pinhole to image the plasma in two dimensions (2-D). The advantages of this tangential camera system include its compactness, high efficiency, energy discrimination in bands, and selectivity of the photon energy range etc. This camera system allows a selection of the viewing area through a remote control of the entire setup. The Philips-Tikhonov algorithm for tangential reconstruction was used to visualize the poloidal cross-sectional images. Phantom tests were performed with synthetic D-shaped plasma images and a comparison with the magnetic equilibrium flux surfaces from the real-time EFIT code obtaining a good agreement between each other. The 2-D X-ray images of the KSTAR plasma were successfully acquired during sawtooth crash, electron cyclotron heating, vertical displacement event, and emissivity from the injected trace Ar impurity. © 2016 Elsevier B.V
The GEMpix detector as new soft X-rays diagnostic tool for laser produced plasmas
No full textLaser produced plasmas lend to several interesting applications. The study of X-ray emission from this kind of plasmas is important not only to characterize plasmas itself but also to study the application of these particular plasmas as intense X-ray sources. In particular several emission configurations can be obtained using different kinds of targets and tuning the characteristics of the laser pulse delivered to the target. Typically, laser pulse duration ranges between a few tens of femtoseconds and tens of nanoseconds, with energies from few mJ to tens of kJ. X-ray photon emissions last for times comparable to the laser pulses and during this time a great number of photons can be emitted. The following paper presents a measure of the soft-X-ray emission on the ECLIPSE laser facility realized with a new triple-GEM gas detector (GEMpix). It is a hybrid gas detector with a C-MOS front-end electronics based on Medipix chips. In the present work, different targets have been used in order to test X-rays of different energies. In this paper, in particular, we present results obtained for copper and iron targets. GEMpix is able to realize a 2D imaging of the X-ray emission from plasma with a signal proportional to the energy released in the gas of the detector active volume. Then through a preliminary single photon equalization realized at the NIXT lab (ENEA), also the number of photons reaching the area of the detector has been estimated. © 2016 Author(s)
Comparative analyses of current biobased economy policies and strategic india-EU partnership
No full textBoth India and Europe still depend heavily on fossil fuels and both face the controversial challenging tradeoff between the food supply on the one side, and biomass production on the other. The present studies show that both regions share a similar idealistic view when it comes to sustainability - both striving towards a low-carbon economy with emphasis on '‘green’' energy. The government policy on bioenergy and bio-based products plays an important role in the development and transition towards a bio-based economy in both the regions. The significance of the cooperation will be influenced by policies affecting multiple sectors such as agriculture, resources, research, industry and trade. The study will help in identifying relevant policies and quantifying their specific impacts on market including its effects on bilateral sustainability relationship. © 2017, ETA-Florence Renewable Energies. All rights reserved
An insight to India’s biomass production and biowaste management: Scope and challenges
No full textBeing a developing nation and having an agriculture based economy, India has a promising biomass resource. There is a huge scope for establishing bio based economy in India due to the availability of wide varieties and large quantities of biomass. In the current Pan India survey, to assess the availability of different types of biomass, was carried out. A survey was also conducted on the projects and programs financed on the biomass production and conversion through different processes. On the basis of this survey, two separate inventories (Biomass and Projects and programs), were prepared. From the preparation of the biomass inventory, it was found that to a certain extent only agricultural biomass production data is available which includes the major biomass sources from Sugar crops (117.42 MMT) (Million Metric Tons) followed by Oil crops (97.3 MMT) and Starch crops (29.74 MMT). Among biowaste, recorded data on only biodegradable fraction of the waste could be found which was estimated to be 25.547 MTPY (Million Tons per Year). The total budget allotted towards these projects was INR 2213 million (approximately 350 Euros). The present study portrays the availability of the enormous source of varied biomass and its roadmap towards better utilization through collaboration with other countries that might help proper use of all the available biomass resources and establishing the biobased economy in India. © 2016 ETA-Florence Renewable Energies
An hybrid detector GEM-ASIC for 2-D soft X-ray imaging for laser produced plasma and pulsed sources
No full textThe following paper presents a new 2-D detector ('GEMpix') in the soft X-ray range, having a wide dynamic range thanks to its intrisic gain, working in charge integration mode to be used for diagnosing laser produced plasma (LPP) or X-ray pulsed sources. It is a gas detector based on the Gas Electron Multiplier (GEM) technology with a quad-medipix chip as read-out electronics. In our prototype, the substitution of semiconductor material with a gas triple-GEM allows several advantages with respect to the detectors commonly used in LPP, as X-ray CCDs and Micro Channel Plates or Image Plates. In these experiments the configuration Time-over-Threshold (ToT) has been used, to measure the total charge released to the gas and collected by each pixel, integrated over the X-ray burst duration. Intensity response and spatial resolution has been measured first in laboratory for calibration, as function of the voltage applied to the GEMs, in single photon regime with energies between 3.7 and 17 keV. Subsequently it has been tested at the ABC laser facility (ENEA, Frascati). In this case, we measured the X-rays produced when the ABC neodymium laser, with pulse of 50 J and 3 ns time width, hits plane targets of aluminum. 2-D images have been acquired by means of a pinhole configuration with magnification 1.5 and 50 μm of spatial resolution. The results are encouraging regarding the capability of this imaging detector to work in experiments where soft X-ray emissivity varies over many orders of magnitude. © 2016 IOP Publishing Ltd and Sissa Medialab srl
Macrobiotus neuquensis Rossi, Claps & Ardohain, 2009, sp. nov.
No full textMacrobiotus neuquensis sp. nov. Figs. 1–2 Material examined: The holotype and the paratypes are from moss samples on soil and rock collected in Hua Hum, Junín de los Andes, at ca. 700 m asl (40 °07’S 71 ° 39 ’ W), and from mosses on soil and lichen on a tree near Rucachoroi Lake, Aluminé, at ca. 900 m asl (39 ° 12 ’ S, 70 ° 55 ’ W), collected in December, 2004. Type repository: The holotype (slide N° Nq. 6.6) is preserved at the Museum of La Plata (La Plata University). The paratypes are preserved in the collection of G. Rossi and M. C. Claps. Specific diagnosis: Macrobiotus with an oral-cavity armature of the harmsworthi type, three macroplacoids, and one microplacoid; with eye spots, cuticle smooth, legs without granulation, claws of the hufelandi type, lunules smooth on all legs, the presence of a cuticular bar on the first three pairs of legs, and a refractile zone. These structures are less visible on the fourth pair of legs. The eggs have conical processes with reticular sculpture, all of them in contact with each other. The chorion is invisible. Description of the holotype: The body length is 503.4 µm. The body (Fig. 1 A) is transparent (white) with eyes in anterior position (Fig. 2 A). The cuticle is smooth, without pores or pearls. The mouth is anterior and surrounded by a ring of 10 peribuccal lamellae. The oral-cavity armature is of the harmsworthi type. The teeth of the anterior band—or first band according to the Michalczyk and Kaczmarek (2003) terminology—are smaller, within the anterior border, and are in contact with the lamellae. The posterior band of teeth in the shape of a crown (second band) consists of conical teeth with granules in the posterior portion. The transverse ridges (third band) are small, while the laterals have a smooth margin. The buccal tube is 52 µm long and 10 µm wide (pt = 19.2) (Figs. 1 B, 2 A). Stylet supports are inserted on the buccal tube at 38 µm (pt = 73). The pharyngeal bulb is oval with distinct, triangular apophyses, three macroplacoids, and a microplacoid. The first macroplacoid is wider in the middle section, its length being 9.3 µm (pt = 17.8); the second, more pyramidal, is 8.2 µm long (pt = 15.7); the third is 10.2 µm long (pt = 19.6) and with a structurally different constriction in its terminal part. The microplacoid is 6 µm long (pt = 11.5) and separate from the third macroplacoid. The macroplacoid row is 28 µm long (pt = 53.8; Figs. 1 B, 2 A). The claws are of the hufelandi type, having primary branches with distinct accessory points (Fig. 2 B). The lunules are smooth on all legs (Fig. 2 C). Between the lunules and the refractile zone of the first three pairs of legs there is a cuticular bar (Fig. 2 B), only visible under phase contrast or by DIC and not detected on the fourth pair of legs. On the first pair of legs, the primary branch has a basal portion and measures 12 µm (pt = 23.0), while the secondary branch is 10.5 µm long (pt = 20.1). On the second pair of legs, the primary and secondary branches are 12 (pt = 23.0) and 10 µm (pt = 19.2), respectively. On the third and fourth pair of legs, these branches measure 11 (pt = 21.1) and 8 µm (pt = 15.3) and 11 (pt = 21.12) and 9 µm (pt = 17.3), respectively. The eggs, laid freely, are spherical and contain conical processes having a truncated apex (Fig. 2 D). The processes, 9–12 around the circumference, have a 10–25 µm diameter at their base (Fig. 2 F). The surface of the processes contains dense and uniform reticular sculpture with isodiametric meshes (Fig. 2 E). The bases of the processes are in contact, and the union with the shell is by either connecting cords or a continuation of the sculpture itself, for this reason the shell is not visible (Fig. 2 F). The processes are 7–15 µm height. We found one egg with an embryo (Table 2), thus allowing us to confirm that the eggs are without a doubt from M. neuquensis sp. nov. (Fig. 2 D). Etymology: The name neuquensis refers to the province that includes the locus typicus of this new species. Differential diagnosis: Macrobiotus neuquensis sp. nov. belongs to the harmsworthi group, whose species exhibit the following characteristics in common: three macroplacoids in the form of an arch, a microplacoid in the pharyngeal bulb, plus a cuticle without pores. The presence of the cuticular bar and a refractile zone in the legs along with the eggs having conical processes in contact with one another are the principal characteristics differentiating M. neuquensis sp. nov. from the other species of the group. This new species is similar to Macrobiotus chieregoi Maucci & Durante 1980, but differs from the latter by having eyes and a wider buccal tube. In addition, the processes of the eggs of M. neuquensis sp. nov. are shorter than those of M. chieregoi. Macrobiotus neuquensis sp. nov. differs from Macrobiotus krynauwi Dastych & Harris 1995 in having a smooth cuticle without pearls, a longer and wider buccal tube, bigger macroplacoids, and smaller claws. Macrobiotus neuquensis sp. nov. also differs from Macrobiotus blocki Dastych 1984 and Macrobiotus ovostriatus Pilato & Patané 1998 with respect to the characteristics of the eggs (Table 3). Macrobiotus neuquensis sp. nov. is furthermore unlike Macrobiotus reinhardti Michalczyk & Kaczmarek 2003 in having a shorter third macroplacoid, a wider buccal tube, and longer processes on the eggs, among other morphological features. Remarks: Measurements and pt values of selected morphological structures for all specimens are presented in Table 2. Diameter 87–94 42–55 69–84 43–82 70–90 64–70 98–115 without processesPublished as part of Rossi, Gustavo, Claps, Maria & Ardohain, Diego, 2009, Tardigrades from northwestern Patagonia (Neuquén Province, Argentina) with the description of three new species, pp. 21-36 in Zootaxa 2095 on pages 24-28, DOI: 10.5281/zenodo.18761
Evidence for increasing rainfall extremes remains elusive at large spatial scales: the case of Italy
No full textThe widespread perception of an increase in the severity of extreme rainstorms has not found yet clear confirmation in the scientific literature, often showing vastly different results. Especially for short‐duration extremes, spatial heterogeneities can affect the outcomes of large‐scale trend analyses, providing misleading results dependent on the adopted spatial domain. Based on the availability of a renewed and comprehensive database, the present work assesses the presence of regional trends in the magnitude and frequency of annual rainfall maxima for sub‐daily durations in Italy. Versions of the Mann‐Kendall test and a record‐breaking analysis, that considers the spatial correlation, have been adopted for the scope. Significant trends do not appear at the whole‐country scale, but distinct patterns of change emerge in smaller domains having homogeneous geographical characteristics. Results of the study underline the importance of a multi‐scale approach to regional trend analysis and the need of more advanced explanations of localized trends
Results and performances of X-ray imaging GEM cameras on FTU (1-D), KSTAR (2-D) and progresses of future experimental set up on W7-X and EAST Facilities
No full textThe triple Gas Electron Multiplier (GEM) is a good candidate for the observation of the plasma volume emitting X-rays photons in the energy band up to 30 keV. The GEM camera system can be simply installed outside the port of a fusion device and it's a micropattern proportional gas detector which consists of an ionization gap, where X-rays photon conversion occurs, three consecutive foils working as amplification stage and finally a dedicated printed circuit board. Its simple experimental setup can be made in different configurations with 1D or 2D imaging possibilities: perpendicular GEM camera allows a 1D emissivity profile reconstruction instead a tangential GEM camera allows a poloidal cross-section image. Moreover, they offer high sensitivity, noise free, optical flexibility (zooming and tilting, magnification 10× up to 30×), high contrast, high dynamic range (6 orders of magnitude) and good time resolution (submillisecond). In this work several experimental results already observed on the Frascati Tokamak Upgrade (FTU) and the Korean Superconducting Tokamak Advanced Research (KSTAR) devices will be presented. The perpendicular installation on FTU allows a 1D radial profile with 128 lines of sight, while thanks to the 2D tangential view of the plasma, the reconstruction of the cross section has been done on KSTAR. Between them there are dynamic and precursors of sawtooth, effects of Edge Localized Mode (ELM) in the core and possible interplay between core and edge in ELMs (high m modes), effects of plasma rotation in the core, dynamic of injected impurities in the outer part of the plasma or also impurity accumulation and localized effects of additional heating. Installation of GEM systems is planned on Wendelstein 7-X (W7-X) and the Experimental Advanced Superconducting Tokamak (EAST) also for their robustness and flexibility X-rays detection in presence of high radiative environments (neutrons and gammas). In future applications on the above mentioned fusion devices, another possibility under evaluation is to use standard tomographic methods using two orthogonal GEM camera systems. © 2017 IOP Publishing Ltd and Sissa Medialab
Supervised flood attenuation in presence of reservoirs: a ranking method
No full textFlood attenuation performance of dams is investigated here considering 56 reservoirs in Piemonte Region. Supervised attenuation through pre-emptive drawdown is assessed using a ranking procedure
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