8,286 research outputs found
Shear bands formation in different engineering materials subjected to dynamic compression
No full textDuring dynamic compression tests, different mechanisms occur at the micro-structural level, resulting in a competition among strain hardening, strain rate hardening and thermal softening. The softening effect is due to dynamic recovery and dynamic recrystallization. If the hardening effects become less effective than softening ones, the material could become unstable, forming narrow bands in which the deformation concentrate involving (quasi) adiabatic conditions and an unpredicted catastrophic failure occurs. These narrow bands are called Adiabatic Shearing Bands (ASB). This type of instability can be observed in different type of materials: polymeric materials due to combination between temperature and strain rate, and in Titanium alloy and Aluminum alloy due to strain rate effects. In this work, an analysis about adiabatic shear bands on three different types of materials is described. Compression tests of Titanium alloy (Ti-4Al-6V), Aluminum alloy (AA 7075-T6) and Polymeric material (Polypropylene) have been carried out in quasi-static and dynamic condition, the lasts ones by a Split Hopkinson Bar
Chartoscirta geminata Mancini 1952
No full textChartoscirta geminata (A. Costa, 1853) Chartoscirta geminata Mancini 1952: 5; Servadei 1967: 265; Faraci and Rizzotti Vlach 1986: 33; 1992: 47; Carapezza and Faraci 2005: CD-ROM; 2007: CD-ROM. Chartoscirta geminata var. venustula Mancini 1935: 14; Mancini 1952: 5. Chartoscirta geminata var. nigerrima Mancini 1952: 5. Chartoscirta geminata f. typica Filippi 1957: 41. Chartoscirta geminata f. venustula Filippi 1957: 41; Servadei 1967: 265. Chartoscirta geminata f. nigerrima Filippi 1957: 41; Servadei 1967: 265. Records. Capraia. San Rocco, VI.1930, C. Mancini leg., 2 exx, CMG (Mancini 1935 as “[Isola di Capraia] Due esemplari a S. Rocco in giugno” sub C. geminata var. venustula Scott; Mancini 1952 as “Is. Capraia” sub C. geminata var. venustula Scott; Filippi 1957 as “arcipelago toscano […] f. venustula Scott. […] Isola Capraia (Mancini 1952)”; Servadei 1967 as “I. Capraia: Mancini 1935, 1952 b, Filippi 1957 ” sub C. geminata f. venustula Scott; Faraci & Rizzotti Vlach 1992 as “Is. Capraia, S. Rocco, VI.1930, 2 [exx], Mancini C. [leg.], Mancini, in Museo civico di St. naturale - Genova [collection]”; Carapezza & Faraci 2005; 2007 as “I. Capraia, S. Rocco / Mancini, 1935 / 1930” and “I. Capraia, S. Rocco / 100 [m] / Faraci, Rizzotti Vlach, 1992 / 1930”). Elba. Monte Perone, Castagnone, Campo nell’Elba (LI), 6.VIII.2012, L. Forbicioni leg., 1 ex, CFC. Montecristo. Cala Corfù, 27.VI.1978, R. Poggi leg., 1 ex, MSNG (Faraci & Rizzotti Vlach 1986 as “[Isola di Montecristo] 1 ex. Cala Corfù, 27.IX. 1983 m 150, l. Poggi”; Carapezza & Faraci 2005; 2007 as “I. Montecristo / Cala Corfù / Faraci, Rizzotti Vlach, 1986 / 1978”); Valle dei Lecci, 150 m, 28.VI.1978, R. Poggi leg., 1 ex, CLT (Faraci & Rizzotti Vlach 1992 as “Is. di Montecristo, Valle dei Lecci, 28.VI. 1978, 150 m, 1 [ex], Poggi R. [leg.], Livio Tamanini - Rovereto [collection]”; Carapezza & Faraci 2005; 2007 as “I. di Montecristo, Valle dei Lecci / 150 [m] / Faraci, Rizzotti Vlach, 1992 / 1978”); Valle dei Lecci, 27.IX.1983, R. Poggi leg., 2 exx, MSNG (Faraci & Rizzotti Vlach 1986 as “[Isola di Montecristo] 2 exx. Valle dei Lecci, 27.IX. 1983 m 150, l. Poggi”; Carapezza & Faraci 2005; 2007 as “I. Montecristo, Valle dei Lecci / Faraci, Rizzotti Vlach, 1986 / 1983”). Giglio. Giglio Island, III.[1900–1902], G. Doria leg., 1 ex, MSNG; idem, IX.[1900–1902], G. Doria leg., 2 exx, MSNG; idem, XII.[1900–1902], G. Doria leg., 1 ex, MSNG (Mancini 1935 as “Is. Giglio”; Mancini 1952 as “[Isola del Giglio] 1 es. marzo, 2 es. settembre, 1 es. dicembre” sub C. geminata Costa “Forma tipica”; Filippi 1957 as “arcipelago toscano (Mancini 1952) […] forma typica ”; Servadei 1967 as “I. Giglio: Mancini 1952, Filippo 1957” sub C. geminata Costa; Giglio Island, IV.[1900–1902], G. Doria leg., 2 exx, MSNG; idem, V.[1900–1902], G. Doria leg., 1 ex, MSNG; idem, VI.[1900– 1902], G. Doria leg., 1 ex, MSNG; idem, VIII.[1900–1902], G. Doria leg., 2 exx, MSNG (Mancini 1935 as “Is. Giglio”; Mancini 1952 as “[Isola del Giglio] 2 es. aprile, 1 es. maggio, 1 es. giugno, 1 es. agosto” sub C. geminata var. venustula Scott; Filippi 1957 as “arcipelago toscano (Mancini 1952) […] f. venustula Scott.”; Servadei 1967 as “I. Giglio: Mancini 1935, 1952 b” sub C. geminata f. venustula Scott); Giglio Island, [1900–1902], G. Doria leg., 1 ex, MSNG (Mancini 1935 as “Is. Giglio”; Mancini 1952 as “[Isola del Giglio] 1 es.” sub C. geminata var. nigerrima Mancini; Filippi 1957 as “arcipelago toscano […] f. nigerrima Mancini […] isola del Giglio (Mancini 1952)”; Servadei 1967 as “I. Giglio: Mancini 1952 b, Filippi 1957 ” sub C. geminata f. nigerrima Mancini); Giglio Island, VI.1900, G. Doria leg., 2 exx, MSNG (Faraci & Rizzotti Vlach 1992 as “Is. del Giglio, VI.1900, 2 [exx], Doria G. [leg.], Museo Civico di St. naturale - Genova [collection]”; Carapezza & Faraci 2005; 2007 as “I. del Giglio / 100 [m] / Faraci, Rizzotti Vlach, 1992 / 1900”); Giglio Island, III.1901, G. Doria leg., 1 ex, MSNG; idem, IV.1901, G. Doria leg., 2 exx, MSNG; idem, V.1901, G. Doria leg., 1 ex, MSNG; idem, VI.1901, G. Doria leg., 1 ex, MSNG (Faraci & Rizzotti Vlach 1992 as “Is. del Giglio, III.1901, 1 [ex], Doria G. [leg.], Museo Civico di St. naturale - Genova [collection]; id., IV.1901, 2 [exx], id.; id., V.1901, 1 [ex], id.; id., VI.1901, 1 [ex], id.”; Carapezza & Faraci 2005; 2007 as “I. del Giglio / 100 [m] / Faraci, Rizzotti Vlach, 1992 / 1901”); Giglio Island, VIII.1902, G. Doria leg., 1 ex, MSNG (Faraci & Rizzotti Vlach 1992 as “Is. del Giglio, VIII.1902, 1 [ex], Doria G. [leg.], Museo Civico di St. naturale - Genova [collection]”; Carapezza & Faraci 2005; 2007 as “I. del Giglio / 100 [m] / Faraci, Rizzotti Vlach, 1992 / 1902”). Remarks. First record for the Isle of Elba. Doria’s records reported by Faraci and Rizzotti Vlach (1992) and Carapezza and Faraci (2005, 2007) are most probably the same ones as Mancini (1935, 1952), but they were listed separately to avoid confusion, pending a revision of Giacomo Doria’s samplings.Published as part of Cianferoni, Fabio, Rocchi, Saverio & Terzani, Fabio, 2013, Nepomorpha, Gerromorpha and Leptopodomorpha (Hemiptera: Heteroptera) of the Tuscan Archipelago (Italy), pp. 302-320 in Zootaxa 3669 (3) on pages 314-315, DOI: 10.11646/zootaxa.3669.3.6, http://zenodo.org/record/526667
Evaluation of Friction at High Strain Rate using the Split Hopkinson Bar
No full textThe present work aims at studying the influence of strain rate on the frictional behaviour of AA7075 aluminium alloy in the O-annealed temper state. To this purpose, ring compression tests were performed both under quasi-static and dynamic loading conditions. The high strain rate tests were carried out by means of the Split Hopkinson Tension-Compression Bar in the direct version. In both cases, hollow cylindrical samples, characterised by an initial outer diameter to inner diameter to height ratio of 6:3:2, were tested under dry condition and by lubricating with molybdenum disulphide grease. The different frictional behaviour exhibited by AA7075-O under quasi-static and dynamic loading conditions can be attributed to the strain rate effect both on the plastic flow behaviour of the deformed material, and on the thickness of the lubricant film
Archaeology and archaeobotany of a reclamation land – Vie Vinarola – G.B. Aleotti, Argenta, (Ferrara, Northern Italy). Late XIII – Middle XIV century A.D.
No full textIn 1993 during the construction of an underground car park in the historic center of Argenta (Ferrara, italy), a reclaimed area 5 m wide extending from North to South consisting of a canal and, probabily, a ditch, approximately 2,70 m below the road, dating back on an archaeological basis, to the Middle Ages, was discovered by the Soprintendenza per i Beni Archeologici dell'Emilia Roamgna. The archaeological area studied consisted of peaty soil in which large stakes are fixed in four rows, alternating with fencesformed by posts tied toghether with wicker, interpreted as a reclaimed canal. At that time, a more compacted soil was obtained by using rubbish of all sorts including objects. Pollen analysis and hand-made wooden objects have made it possibile to obtain an outline of the characteristics of the natural landscape of Argenta during the XIII-XIV centuries. It was characterised by a large scale clearance of the vegetation, with trhe forest providing a background to the settlements, consisting of a large cultivation of cereals an Vitis
Oxygen transfer capability in sfs-h natural wwt studied on engineering-unibo pilot plant
No full textThe increasing interest on natural wastewater treatment systems implementation for large flow rates involves to study in detail the process features. Recently, the full scale implementation of horizontal sub-surface flow (SFS-H) phytotreatment systems in irrigation channels is studied. Biological processes in SFS-H phytotreatment systems for wastewater treatment are regulated by vertical profiles of dissolved oxygen which balance and distribute the aerobic/anoxic/anaerobic conditions in filtration bed. Nitrification in horizontal flow systems is strongly influenced by the limited oxygen transfer capability so hybrid systems (vertical and horizontal flow) are frequently implemented to improve the nitrification/denitrification rates. Consequently, the oxygen transfer capability in SFS-H natural ponds is a key point for their efficient implementation. Thus, a monitoring study has been carried on the Engineering-UNIBO pilot plant in order to measure and improve the oxygen transfer capability in SFS-H natural pond. The pilot plant consists of two tanks with the same sand bed and one of them also contain plants (Phragmites Australis). The pilot plant was alternatively fed by clean water and wastewater from the University sewage system. Consequently, four work conditions were studied and compared: 1) clean water and tank without plants 2) clean water and tank with plants 3) wastewater and tank without plants 4) wastewater and tank with plants. The Dissolved Oxygen (DO) and Temperature (T) were measured at two levels corresponding to surface and bottom of the tank in order to evaluate the horizontal and vertical variations. As expected, the monitoring results show that in case of clean water inlet the DO variations are very low even if an increase was observed when the hydraulic retention time was 30 h, while in case of wastewater inlet DO increase reach around 30%
Selection of projects’ primary and secondary mitigation actions through optimization methods in nuclear decommissioning projects
No full textThe growing interest in nuclear power has brought attention back to the general condition of nuclear power plants. In fact, according to the main intergovernmental organisations responsible for nuclear energy, more than 150 basic nuclear facilities (in-service reactors, downgraded reactors, fuel fabrication plants, reprocessing plants, and waste storage areas) should be seriously checked for safety reasons, while many others are close to the end of their lifecycles (lasting generally around 50–60 years) – thus, there is an urgent need for research into the management of Nuclear Decommissioning Projects (NDPs). In particular, the high complexity of these projects makes it fundamental to implement strong risk management procedures, aimed at identifying and analyzing all possible hazards, and finding and implementing the appropriate risk response actions. This paper focuses on the selection of mitigation actions and proposes optimizationisation algorithms to select the most time-effective set of risk responses for a nuclear decommissioning project. A single case study of an Italian completed NDP was employed to investigate the application of optimization techniques in the mitigation action selection phase, considering also secondary risks and secondary mitigation action. The results show that the performance that would have been achieved through the optimization algorithm would have been superior, both from the point of view of a reduced time delay, and in terms of a more effective balance between overall risk coverage and implementation costs
HORIZONTAL SUBSURFACE FLOW PHYTOTREATMENT FOR DOMESTIC WASTEWATER TREATMENT: NITRIFICATION-DENITRIFICATION EFFICIENCY TESTED ON BERTALIA-UNIBO PILOT PLANT
No full textClimate change and environmental crises have a very big impact on water cycle in terms of water availability. The scarcity of water impacts agricultural production, while its quality influences the safety of agricultural products and consequently public health. A sustainable way to supplement agricultural production and industrial water needs stands in the reuse of wastewater. Moreover, it is so necessary to develop smart, sustainable and efficient wastewater treatment technologies in terms of construction and management cost for small communities. Natural wastewater treatment systems represent a cost-effective treatment, already tested and implemented all around the world. In this context, this study focuses on horizontal sub-surface flow phytotreatment systems implementation with the aim to understand the processes and features involved to optimize both design and technical management phases. This work is a continuation and extension of previous studies conducted by the authors and focuses on nitrification and denitrification processes. To this aim, a pilot plant located on Bertalia-UNIBO campus in Bologna was monitored to evaluate the nitrification-denitrification efficiencies related to seasonal variation of Temperature, dissolved oxygen at different hydraulic retention time. The pilot plant was charged with a domestic wastewater and the emergent macrophytes were Phragmites australis. The tests show good nitrification efficiencies in summer (from 78% to 91%) at HRT more than 12 h and the resulting data were stable at 30h. Winter nitrification efficiencies are lower than summer (44%, 66%) at HRT more than 12 h. As expected, dissolved oxygen was greater in winter than summer. Denitrification efficiency were in the range 40% - 75%, increasing with HRT. Results also show that full scale implementations need HRT equal 30h in order to reach significant nitrification rates
Space Geodesy as a tool for measuring ice surface velocity in the Dome C region and along the ITASE traverse.
No full textDome C was chosen by the European Project for Ice Coring in Antarctica (EPICA) as the site for the drilling of a deep ice core. This paper presents results from geodetic surveys of ice velocities (absolute and relative) at Dome C and along a transect to Terra Nova Bay. The purpose of the surveys was to provide accurate data for the study of ice dynamics, particularly a strain network comprising 37 poles surveyed in 1995 and again in 1999. Data indicate that the ice surface at the poles closest to the topographic summit moves horizontally by up to a few mm a−1 in a direction consistent with downslope motion of the ice sheet, while 25 km from the summit it moves up to 211 mm a−1. The EPICA drilling site yields an interpolated velocity of about 15 ± 10 mm a−1 in a north-northwesterly direction. Analysis of the velocity field and surface topography reveals that the surface flow centre is nearly co-located with the dome summit, and that both are in a steady-state condition. The measured horizontal velocities are consistent with the remote-sensing result and provide accurate ground-truth control for flow mapping. Seven snow–firn cores, up to 53 m deep, were drilled during the Terra Nova Bay–Dome C traverse. Submerged velocity systems were installed at the borehole and measured using the global positioning system (GPS). First results show a steady-state condition. Measured (horizontal) ice velocities increase from the summit of the ice sheet to the coast, reaching about 28 m a−1 at site GPS2A
Hepatitis C virus (HCV) infection may elicit neutralizing antibodies targeting epitopes conserved in all viral genotypes
No full textAnti-hepatitis C virus (HCV) cross-neutralizing human monoclonal antibodies, directed against conserved epitopes on surface E2 glycoprotein, are central tools for understanding virus-host interplay, and for planning strategies for prevention and treatment of this infection. Recently, we developed a research aimed at identifying these antibody specificities. The characteristics of one of these antibodies (Fab e20) were addressed in this study. Firstly, using immunofluorescence and FACS analysis of cells expressing envelope HCV glycoproteins, Fab e20 was able to recognize all HCV genotypes. Secondly, competition assays with a panel of mouse and rat monoclonals, and alanine scanning mutagenesis analyses located the e20 epitope within the CD81 binding site, documenting that three highly conserved HCV/E2 residues (W529, G530 and D535) are critical for e20 binding. Finally, a strong neutralizing activity against HCV pseudoparticles (HCVpp) incorporating envelope glycoproteins of genotypes 1a, 1b, 2a, 2b and 4, and against the cell culture-grown (HCVcc) JFH1 strain, was observed. The data highlight that neutralizing antibodies against HCV epitopes present in all HCV genotypes are elicited during natural infection. Their availability may open new avenues to the understanding of HCV persistence and to the development of strategies for the immune control of this infection
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