189 research outputs found
Data for: Primates bark-stripping trees in forest plantations - A review
No full textThe data file contains data on primates strip-barking trees from plantations or managed forests
Confronto del comportamento di due differenti tipologie di malte geopolimeriche a base di cenere volante
No full textLa sempre maggiore richiesta di materiali da costruzione a ridotto impatto ambientale con la possibilità di riciclare materiali di scarto è stato l’impulso per lo sviluppo di leganti geopolimerici come possibili sostituti del tradizionale cemento Portland per il confezionamento di malte.
La ricerca è stata condotta confrontando le prestazioni di 2 differenti serie di malte a base geopolimerica a parità di classe di resistenza meccanica: R1 ≥ 10MPa, R2 ≥ 15MPa, R3 ≥ 25MPa e R4≥ 45MPa, in accordo con la norma UNI EN 1504-3:2006.
I geopolimeri sono il risultato della reazione chimica tra materiali sorgente e una soluzione alcalina. In questo studio, le malte geopolimeriche sono state confezionate con cenere volante (prima serie) e con cenere volante parzialmente sostituita con cemento alluminoso (seconda serie) come materiali sorgente. Come soluzione alcalina è stata utilizzata una soluzione di silicato di sodio e di idrossido di sodio, in assenza di cemento alluminoso, o di potassio, in presenza di cemento alluminoso, a differenti concentrazioni. Tutte le malte geopolimeriche sono state preparate con rapporto sabbia/cenere di 3:1, mantenendo sempre pari a 1 il rapporto tra il peso della soluzione di silicato di sodio e la soluzione di NaOH o KOH.
In generale, nonostante la minore permeabilità al vapore rispetto alle miscele con NaOH, le malte con KOH hanno ottenuto pari assorbimento d’acqua per capillarità, una maggiore aderenza al mattone e un minore ritiro libero. Inoltre, la presenza del cemento alluminoso e dell’idrossido di potassio nei geopolimeri ha contribuito alla riduzione delle efflorescenze
Financial analysis of renewable energy investments in Italy in 2013
No full textThe present paper analyses the financial aspects of
investing in different renewable energy technologies:
photovoltaic, wind and hydro. To perform the financial analysis
on the afore-mentioned plants for different types of investors,
three different sizes of system have been considered: 5 kW for
domestic uses, 20 kW for small business activities and 1 MW for companies involved in producing and selling energy. A
description of present incentives in renewable energy production
in Italy in 2013 has been reported. For each case study a
comparison of different cost solution has been proposed. To
evaluate the financial convenience of the investments specific
economical indices have been used and compared.The paper analyses the financial aspects of investing in different renewable energy technologies: photovoltaic, wind and hydro. To perform the financial analysis on the afore-mentioned plants for different types of investors, three different sizes of system have been considered: 5 kW for domestic uses, 20 kW for small business activities and 1 MW for companies involved in producing and selling energy. A description of present incentives in renewable energy production in Italy in 2013 has been reported. For each case study a comparison of different cost solution has been proposed. To evaluate the financial convenience of the investments specific economical indices have been used and compared
Degradation of the surfaces exposed to the space environment
Get PDFThe presence of several atomic species in the LEO (Low Earth Orbits) could be considered one of the reasons for the degradation of the surfaces exposed to the Space Environment. At an average height of 400 Km (the altitude of International Space Station), the concentration of the main atomic species during the high sun activity are: 1.5 x 10(9) cm(-3) for atomic oxygen (AO), 1.6 x 10(8) cm(-3) for molecular nitrogen (N-2) and 1.4 x 10(8) m(-3) for atomic nitrogen (N). The energy with which the atoms collide with the surface of orbiting vehicle depends on the relative speed of the vehicle itself. For instance, the atoms colliding the International Space Station (ISS) (orbit average height: 400 Km; relative speed: 7.5 Km/s) have an energy of 8 eV for N-2, 5 eV for OA and 4 eV for N. The atomic oxygen is the most abundant species presents in LEO and it is considered the main responsible of the thermal, optical and mechanical alteration of the surfaces exposed to the Space Environment. Different hypothesis are reported in literature in order to explain the physical/chemical mechanisms that govern the material degradation in the Space, but no conclusion has been reached. In the energy range of few of eV, the main mechanism with which colliding atoms transfer its energy to the atoms of the surface is by phonons. In this paper the effect of an oxygen ion beam produced in the space environment simulator on materials for Space applications is studied in the frame of the thermal spike theory. Comparison between the measured erosion and the calculated one will be reported. The erosion mechanism will be modelled in order to understand the main thermodynamic parameters that govern the interaction between the atomic oxygen and the surface of the tested materials. (c) 2006 Elsevier Ltd. All rights reserved
Loss of Coolant Accident: parametric analysis of the initial period of the depressurization of a BWR vessel with the use of the RELAP4/MOD5 code" (in Italian)
No full textThe document (in Italian) deals with the analysis by computer code RELAP4 of experimental data measured in the PIPER facility. PIPER was installed at the Scalbatraio Laboratory managed by IIN (Istituto di Impianti Nucleari) of University of Pisa. PIPER consisted of a pressure vessel equipped with electrical heaters and rupture nozzle, other than suitable instrumentation (typically temperature and pressure transducers). Namely original instrumentation was developed to measure the jet thrust, the jet impingement loads and the load on internal components following the break opening and the propagation of the depressurization wave upstream from the rupture into the vessel. Pioneering RELAP applications to the analysis of experimental data demonstrated the validation level of the code. Namely, in this report, experimental data of blowdown are compared with code calculations results. The bases were put for better understanding of phenomena like Two-Phase Critical Flow (TPCF), depressurization rate, effect of initial subcooling and of relative position between initial collapsed level and elevation of exist nozzle axis. Key reported data (experiment and corresponding calculation results) are transient pressure and fluid temperatures at different positions in the vessel and in the exit nozzle
Cardiometabolic risk profile in non-obese children with obstructive sleep apnea syndrome
No full textObstructive sleep apnea syndrome (OSAS) in childhood is a complex disease primarily due both to adenotonsillar hypertrophy and pediatric obesity. Notably, inflammation has been recognized as one of the most important shared pathogenic factor between obesity and OSAS resulting in an increased cardiometabolic risk for these patients. To date, evidence is still limited in non-obese population with OSAS. We aimed to evaluate the cardiometabolic risk profile of a pediatric population of non-obese subjects affected by OSAS. A total of 128 school-aged children (mean age 9.70 ± 3.43) diagnosed with OSAS and 213 non-OSAS children (mean age 9.52 ± 3.35) as control group were enrolled. All subjects underwent a complete clinical and biochemical assessment (including white blood cell count (WBC), platelet count (PLT), mean platelet volume (MPV), % of neutrophils (NEU%), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), serum glucose, aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyl transpeptidase (GGT), uric acid, fasting insulin, iron, ferritin, and transferrin levels). A significant association between inflammation markers (including WBC, PLT, MPV, NEU%, ferritin, CPR, and ESR) and OSAS was found (all p < 0.001). Children with OSAS also showed increased transaminase, glucose, uric acid, and insulin levels (all p < 0.001) compared to healthy controls. Conclusion: Taken together, these findings suggested a worse cardiometabolic profile in non-obese children with OSAS. Given the pivotal pathogenic role of inflammation both for hypoxiemia and metabolic derangements, therapeutic strategies for OSAS might also counteract the increased cardiometabolic risk of these patients, by improving their long-term quality of life.What is Known:• Pediatric OSAS has shown a close relationship with obesity and its cardiometabolic comorbidities.• Inflammation represents the hallmark of both obesity and OSAS.What is New:• Non obese children with OSAS presented with a worse cardiometabolic risk profile.• OSAS treatment might serve as an effective approach also for the increased cardiometabolic risk of these children
Sleep Macrostructure and NREM Sleep Instability Analysis in Pediatric Developmental Coordination Disorder
Get PDFDevelopmental Coordination Disorder (DCD) is considered to be abnormal motor skills learning, identified by clumsiness, slowness, and/or motor inaccuracy impairing the daily-life activities in all ages of life, in the absence of sensory, cognitive, or neurological deficits impairment. The present research focuses on studying DCD sleep structure and Cyclic Alternating Pattern (CAP) parameters with a full overnight polysomnography and to study the putative correlations between sleep architecture and CAP parameters with motor coordination skills. The study was a cross-sectional design involving 42 children (26M/16F; mean age 10.12 ± 1.98) selected as a DCD group compared with 79 children (49M/30F; mean age 9.94 ± 2.84) identified as typical (no-DCD) for motor ability and sleep macrostructural parameters according to the MABC-2 and polysomnographic (PSG) evaluations. The two groups (DCD and non-DCD) were similar for age (p = 0.715) and gender (p = 0.854). More significant differences in sleep architecture and CAP parameters were found between two groups and significant correlations were identified between sleep parameters and motor coordination skills in the study population. In conclusion, our data show relevant abnormalities in sleep structure of DCD children and suggest a role for rapid components of A phases on motor coordination development
INFLAMMATORY MYOFIBROBLASTIC TUMORS IN CHILDREN : THEIR RELATIONSHIP WITH HHV8 INFECTION AND PROGNOSTIC ROLE OF HISTOLOGY
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