Search results for "source"
showing 10 items of 6139 documents
An electrospray ionization Fourier transform ion cyclotron resonance mass spectrometric study of the gas-phase stabilities and fragmentation ofN-alky…
2006
Five N-alkylated ammonium resorcarene derivatives, differing either in the nitrogen atom or in the lower rim alkyl chain, were studied using electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. The main purpose was to clarify the fragmentation and the relative stabilities of the protonated molecules by collision-induced dissociation (CID) experiments. The results indicate that fragmentation of the upper rim alkyl amino substituents at the 2-position occurs readily. Variation in the gas-phase stabilities of these molecules was also observed. In addition, the proposed fragmentation pathways are depicted.
Physical Activity Levels and Related Energy Expenditure during COVID-19 Quarantine among the Sicilian Active Population: A Cross-Sectional Online Sur…
2020
Background: During the coronavirus disease 2019 (COVID-19) pandemic, the Italian government has adopted containment measures to control the virus’s spread, including limitations to the practice of physical activity (PA). The aim of this study was to estimate the levels of PA, expressed as energy expenditure (MET–minute/week), among the physically active Sicilian population before and during the last seven days of the COVID-19 quarantine. Furthermore, the relation between this parameter and specific demographic and anthropometric variables was analyzed. Methods: 802 Sicilian physically active participants (mean age: 32.27 ± 12.81 years; BMI: 23.44 ± 3.33 kg/m2) were included in the study and…
A Rayleigh-Ritz approach for postbuckling analysis of variable angle tow composite stiffened panels
2018
Abstract A Rayleigh-Ritz solution approach for generally restrained multilayered variable angle tow stiffened plates in postbuckling regime is presented. The plate model is based on the first order shear deformation theory and accounts for geometrical nonlinearity through the von Karman’s assumptions. Stiffened plates are modelled as assembly of plate-like elements and penalty techniques are used to join the elements in the assembled structure and to apply the kinematical boundary conditions. General symmetric and unsymmetric stacking sequences are considered and Legendre orthogonal polynomials are employed to build the trial functions. A computer code was developed to implement the propose…
Forest management planning at different geographic levels in Italy: hierarchy, current tools and ongoing development
2009
This paper examines the current status of forest management tools and their pplication at different levels in Italy where the majority of land planning has been and is still being done at the “micro-scale”, meaning that specific local issues are dealt with locally. Starting from international European Union law, the authors review the forest acts that led from the National Forest Plan (NFP) to smaller scales, in relation to their geographic and territorial applicability. Scaling down from the NFP to the local level the various Italian forest programmes and plans are analysed according to a vertical logic (hierarchical mode): Regional Forest Programme (RFP), Territorial (i.e. sub-regional) F…
Photoelectron Emission from Metal Surfaces Induced by Radiation Emitted by a 14 GHz Electron Cyclotron Resonance Ion Source
2015
Photoelectron emission measurements have been performed using a room-temperature 14 GHz ECR ion source. It is shown that the photoelectron emission from Al, Cu, and stainless steel (SAE 304) surfaces, which are common plasma chamber materials, is predominantly caused by radiation emitted from plasma with energies between 8 eV and 1 keV. Characteristic X-ray emission and bremsstrahlung from plasma have a negligible contribution to the photoelectron emission. It is estimated from the measured data that the maximum conceivable photoelectron flux from plasma chamber walls is on the order of 10% of the estimated total electron losses from the plasma. peerReviewed
L'allocation de ressources par élève dans le système éducatif français : point de vue d'un économiste
1993
This article examines why it is interesting to have a better knowledge of unit costs in educational systems, and to analyse differences between levels of education, between schools and between countries. It underlines the fact that few studies have been carried out up to now, and that little agreement exists among specialists concerning the methodologies for estimating costs. In spite or these deficiencies in available information, the author reviews existing case studies in France and in the world, and shows that extensive possibilities of improving the cost-effectiveness of ressources allocation still exist. Comparisons between France and its economic partners show that French unit costs …
Adoption of Green Environmental Practices in Small and Medium-Sized Enterprises: Entrepreneur and Business Policies Patterns in Romania
2021
Current research shows that SMEs’ social and environmental actions are fragmented and informal, and few have formal policies and intentions. At the same time, many SMEs are engaged with environmental policies, often not knowing it. Concurrently, there is a gap between the pro-environmental attitudes of the SMEs managers, who are often seen as the main drivers for the firm’s behavior, and the policies implemented in reality in their firms. To this end, our research’s objective is to explore pro-environmental behavior, both at the individual and firm level, to identify connections between these levels and measures but also with firm’s and managers’ demographics, based on a study of Romanian S…
ERP and Organizational Misfits: An ERP Customization Journey
2016
Abstract Enterprise resource planning (ERP) projects are complex and resource demanding. Some ERP projects fail due to what is called ‘misfit’ between the adopting organization's business requirements and the ERP's functionalities. Existing literature has studied how ERP systems match to different organizations and have argued that there always exists a gap between the business rules embedded in the system, and the practices and processes that exist in organizations. Thus, tailoring might be an important procedure during ERP implementations, in which the ERP customization takes place in order to ensure the compliance with the organizations’ critical business processes and requirements. Via …
Distributed leadership in Finnish and Shanghai schools
2016
The present research employed mixed-methods approach to further theorise distributed leadership and to investigate its manifestations in Finnish and Shanghai schools. The whole research comprised two phases. The first phase contained a meta-analysis (Sub-study I), which systematically reviewed 85 key distributed leadership articles published between 2002 and 2013. The meta-analysis identified two main research paradigms: the descriptive-analytical paradigm and the prescriptive-normative paradigm. It also yielded a resource–agency duality model of distributed leadership. In this model, distributed leadership is seen as a process with both organisational and individual perspectives. From the …
Experimental Validation of Maximum Constant Boost Control and Switching Frequency Optimal for three-phase Quasi-Z-Source Converters
2020
This paper presents a modified modulation scheme for quasi-Z-Source converters, based on the Maximum Constant Boost Control (MCBC) concept and Switching Frequency Optimal (SFO) as reference signal. The effectiveness of the proposed technique is validated by comparing the obtained results (in terms of AC harmonic content and voltage stress) with those carried out from traditional modulation schemes. For this reason, a test bench has been assembled and the benefits of the SFO MCBC modulation scheme have been valuated.