179,266 research outputs found
Evaluation of equilibrium moisture content in ligno-cellulosic residues of olive culture
No full textThe use of ligno-cellulosic residuals from agriculture as means for renewable energy production is well known; nonetheless significant problems still exist on development of bioenergy value chains. Moisture content and hygroscopicity are among these problems. Higher moisture content of the biomass means lower calorific value and higher perishability, hence storage difficulties. For this reason it is important to evaluate how the moisture content of the material varies while it is stored and how the calorific value of the feedstock is affected by it. The purpose of this study is to determine the variation of moisture content and its influence on lower calorific value (LCV) of four types of solid residual biomass: oven dried chipped olive tree trimmings, milled olive pomace; oven dried olive tree trimmings and fresh olive tree trimmings. Moisture content of the samples is calculated by means of thermogravimetric analysis (TGA) according to standard CEN/TS 14774-2:2004, while the LCVs are calculated by means of a calorimeter, following standard UNI EN 14918:2010. All the biomass samples were left to reach equilibrium moisture content (EMC) in a temperature and humidity controlled environment. Two different phases were analyzed with respect to moisture uptake rates: 1) fast moisture uptake rate phase (first four hours of exposure) and 2) slow moisture uptake rate, (the days following the first four hours of exposure). Samples experiencing fast moisture uptake rate, during the first four hours of exposure, were kept in a monitored ambient at T=22 ± 1oC and RH=59 ± 2%, while samples exposed to slow moisture uptake rate were kept in a climatic chamber at three different set of temperature and humidity controlled environment simulating the climatic conditions in different periods of the year in Enna province: 10oC - 80% RH (winter), 15oC - 70% RH (spring/autumn) and 20oC - 55% RH, (summer). The results obtained show that the olive pruning chips (0.425 mm to 1.00 mm and 1.00 mm to 2.00 mm particle size ranges) stored in a heap in a controlled climatic chamber require approximately 20 days to reach EMC. Depending on the particle size range EMCs reach the values of 6.2 and 7.5% by weight in the "summer" condition, 14.3% and 16.9% in "spring/autumn" condition, 24.1% and 28.2% in "winter" condition. Moisture is absorbed gradually over time and results show that in the first four hours, the dry sample exposed to ambient condition (T=22 ± 1 oC and RH=59 ± 2%) reaches a moisture content between 0.75 and 0.96% of its weight; the LCV at equilibrium is evaluated between 18, 576 J•odg-1 and 18, 793 J•odg-1, the higher value related to the bigger particle size range examined. Pomace heap under the same experimental set up and time period, reaches an equilibrium moisture content of 8.5% and 9.7% (summer conditions), 19.2% and 22.0% (spring/autumn condition) and between 30.9% and 34.1% (winter condition). Olive pomace accumulates moisture relatively faster than olive trimmings as dry sample recovers about 1.61% to 1.97% of moisture in the first four hours of exposure. The LCV at equilibrium is determined between 20, 145 J•odg-1 and 20, 436 J•odg-1. Pruning dried samples reach an EMC equal to 6.1% in approximately 25 days, with a LCV equal to18, 921 J•odg-1 ± 1.9%. Heaps of fresh prunings reach an EMC of 8.2% in approximately 20 days; LCV of the feedstock is 19, 356 J•odg-1± 1.6%.©2006-2014 Asian Research Publishing Network (ARPN). All rights reserved
CMS Pixel detector for the Phase I upgrade at HL-LHC
No full textThe CMS pixel detector is part of the complex tracking system of the CMS experiment at the LHC collider (CERN, Geneva CH). It has been designed for a stable operation and optimal performance at the LHC instantaneous luminosity L =10 cms. The future plans of the LHC collider
envisage an increase of the luminosity up to 2.2 L with 7 TeV per proton beam, namely the high luminosity upgrade (HL-LHC) phase I.
In order to maintain the high level of accuracy and efficiency of the tracking in this new challenging condition, a CMS pixel detector upgrade phase I program has been set up. The main goals of the upgrade activity are the material budget reduction in the tracking volume and the increase of the number of hits associated to a charged track. This paper gives an overview of the upgrade project, describes the planned R\&D activities and focuses on the expected improvements of the new CMS pixel detector system
L’Umorismo di Pirandello. Un saggio in maschera (in AA.VV., Il saggio critico. Spunti, proposte, riletture)
No full textEvaluation of Net Energy Obtainable from Combustion of Stabilised Olive Mill By-Products
No full textThis work is aimed at calculating the energy content of the residues from olive oil
production. Olive pulp, olive husk and sludge (a mixture of olive pulp and husk) have been
analyzed separately. Olive Mill Effluents (OME) are normally a problem for olive mill
farms, yet they may be used as feedstock for biomass-fuelled power plants. Nonetheless,
OMEs are characterized by a relatively high humidity content and are produced only during
the olive season. Thus, OME need a stabilization process to be employed as a solid biofuel
throughout the year. The analyses conducted attempt an evaluation of the energy
consumption of a three-stage stabilization process: drying, milling and pelletising. The net
electrical energy available from OME is then calculated as a difference between gross
energy available and energy consumed for stabilization. The gross available electrical
energy was calculated based on direct energy conversion of the stabilized feedstock on a
small scale direct combustion and Organic Rankine Cycle (ORC) turbine. Results show that
OME are suitable for energy production. Approximately 4500 kJ/kg of net electrical energy
may be obtained out of olive sludge or olive pulp, while olive husk shows a potential gross
energy of 3400 kJ/kg
Esercizi di Matematica Generale. Funzioni - Limiti - Calcolo differenziale in R - Studio di funzioni - Ottimizzazione in R^2
No full textIl libro contiene numerosi esercizi svolti e da svolgere, ed anche esercizi tratti da temi d'esame
Technical and economical feasibility of biomass use for power generation in Sicily
No full textBiomass can provide a reliable support for production ofbiofuels while contributing to sustainable management of natural resources. Many countries, including Italy, have introduced important incentive schemes to support the use of biomass for electricity, heat and transportation. This has raised considerable interest towards the use of biomass for energy generation purposes. Nonetheless, the design and installation ofbiomass-fuelled power plants present several critical issues, such as choice and availability of biomass, choice of technology, power plant localization and logistics. The case study tackled in this paper evaluates the economies originated by a 1MW el Organic Rankine Cycle (ORC) turbine coupled with a biomass fuelled boiler, installed in an area close to Palermo (Italy). A Geographical Information System (GIS) was used to localize the power plant and to optimize logistics. The thermodynamics of the plant as a whole were also analyzed. Finally, two different scenarios were simulated for project fnancial evaluation. Copyright © 2010, IGI Global
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Evaluation of Net Energy Obtainable from Combustion of Stabilised Olive Mill By-Products
No full textThis work is aimed at calculating the energy content of the residues from olive oil production. Olive pulp, olive husk and sludge (a mixture of olive pulp and husk) have been analyzed separately. Olive Mill Effluents (OME) are normally a problem for olive mill farms, yet they may be used as feedstock for biomass-fuelled power plants. Nonetheless, OMEs are characterized by a relatively high humidity content and are produced only during the olive season. Thus, OME need a stabilization process to be employed as a solid biofuel throughout the year. The analyses conducted attempt an evaluation of the energy consumption of a three-stage stabilization process: drying, milling and pelletising. The net electrical energy available from OME is then calculated as a difference between gross energy available and energy consumed for stabilization. The gross available electrical energy was calculated based on direct energy conversion of the stabilized feedstock on a small scale direct combustion and Organic Rankine Cycle (ORC) turbine. Results show that OME are suitable for energy production. Approximately 4500 kJ/kg of net electrical energy may be obtained out of olive sludge or olive pulp, while olive husk shows a potential gross energy of 3400 kJ/kg
Interpretare le politiche italiane in materia di asilo attraverso i concetti di securizzazione, politicizzazione e depoliticizzazione.
No full textIl contributo osserva le recenti forme di governo delle migrazioni
forzate in Italia (2018-2019), interpretandole attraverso l’analisi
congiunta delle teorie sulla securizzazione, depoliticizzazione e
politicizzazione. In termini generali, l’implementazione di politiche
emergenziali sembra favorire la coesistenza di queste tendenze negli
attuali processi di policymaking. Questo framework teorico trova poi
una sua prima applicazione empirica nell’analisi dei cosiddetti
Decreti Sicurezza. L’intreccio tra securizzazione, politicizzazione e
depoliticizzazione è significativamente attestato nel contesto di
analisi; tuttavia la natura esplorativa del lavoro non permette di
offrire un’interpretazione analitica ed esaustiva dei processi osservati.
Nelle conclusioni vengono quindi presentate indicazioni per ulteriori
ricerche
- …
