36,414 research outputs found
Positron Annihilation Studies of Nanoholes and Microphase Microphase Formation Control of a PMMA+MMA+TEGDMA Systems
No full text
Building views over semistructured data sources
No full textThe goal of this paper is to present concepts and techniques to build views and organize the information search space of heterogeneous semistructured data sources with respect to expected queries. We formalize the notion of object pattern and of semantic correspondence between object patterns. Object pattern analysis is ontology-driven and leads to the construction of reconciled views of the sources, called global object patterns. Global object patterns mediate between heterogeneous terminology and structure of data in different sources and are used for query formulation and data extraction
A methodology and tool environment for process analysis and reengineering
No full textMost private and public organizations have recently turned their attention to the process by which they operate, to improve service and product quality and customer satisfaction. To support business process reengineering, methods and tools for process modeling and analysis are required. The paper presents the ARTEMIS methodology and associated tool environment for business process analysis for reengineering. In the ARTEMIS methodological framework, business processes are modeled as workflows and are analyzed according to an organizational structure perspective and an operational structure perspective. With these two perspectives, the analyst can plan reengineering interventions based on the degree of autonomy/dependency of organization units in terms of coupling, and the inter-process semantic correspondences, in terms of data and operation similarity, respectively. The ARTEMIS methodology and associated tool environment have been conceived and applied in the framework of the PROGRESS research project. In the paper, we report on a reengineering case study of this project involving the Italian Ministry of Justice
Staightforward heterogeneization of chiral Cu(I) complexes and their applications to Henry and cyclopropanation reactions
No full textHeterogeneous single site catalysts in many cases show superior performances in terms of activity, selectivity and reciclability coupling together the advantages of heterogeneous and homogeneous systems [1]. Cu(I) complexes (see fig. 1), based on functionalised pyridine-containing macrocyclic chiral ligands [2] were heterogeneized on mesoporous ordered and non-ordered silicas (Davisil, MCM-41, etc.) by the SHB method [3] and they were successfully applied to asymmetric cyclopropanation reactions. Materials obtained were fully characterized for metal content, textural properties, hydrogen bonds between Cu complex and surface silanols by a pool of techniques. Catalysts were tested in asymmetric cyclopropanation of olefins employing ethyldiazoacetate (EDA) as carbene precursor and in the Henry or nitro-aldol reaction and they show performances at least comparable to those obtained with the homogeneous counterpart. Tests using both basic and ordered silicas with the aim of exploiting the confinement effect on stereoselectivity are currently in progress.
References
[1] V. Dal Santo, F. Liguori, C. Pirovano and M. Guidotti, Molecules accepted for publication
[2] A. Caselli, F. Cesana, E. Gallo, N. Casati, P. Macchi, M. Sisti, G. Celentano and S. Cenini, Dalton Trans., 2008, 4202–4205.
[3] C. Bianchini, P. Barbaro, V. Dal Santo, R. Gobetto, A. Meli, W. Oberhauser, R. Psaro and F. Vizza, Adv. Synth. Catal., 2001, 343, 41-45.
Aknowledgents
EU through IDECAT Network of Excellence, European Community’s Sixth Framework Programme (contract NMP3-CT-2005-011730) and NANO-HOST “Homogeneous Supported Catalyst Technologies: the sustainable approach to highly-selective, fine chemicals production” Initial Training Network -The People Program Project no. 215193-2, and MIUR through the project “ItalNanoNet” (Rete Nazionale di Ricerca sulle Nanoscienze; prot. no. RBPR05JH2P) are gratefully acknowledged for financial support
Informetrics on M. N. Srinivas
Full text linkM. N. Srinivas, the well known sociologist is widely recognised as architect of modern Indian sociology and social anthropology. His publications have been analysed by year, domain, authorship pattern, channels of communication used. Keywords, etc. The results indicate that the papers published by him are of a nature that qualify him to be a 'role model' for the younger generations to emulate.
By the end of 1995, Srinivas had to his credit 144 papers which, included 33 broad papers in sociology and anthropology; 18 papers in social change; 28 papers in village studies; 12 papers on religion; 17 papers on caste and 36 papers of general popular interest. The periods 1958-61 and 1974-77, when Srinivas was 38-41 and 58-61 years old. were his most productive periods with highest publication activity
Digital Resource Discovery: Semantic Annotation and Matchmaking Techniques
No full textThe Web is a huge container of digital resources, that is, sets of objects that are accessible and manageable by a computer. When dealing with structured queries (rather than with flat list of keywords), model matchmaking is a fundamental task in the digital resource discovery process. This paper presents MAGDA (MApping Generic Discovery Architecture), a reference architecture designed to implement different matchmaking algorithms aimed at defining mappings between digital resource models. The basic conceptual structures of MAGDA are described: a labeled oriented multigraph as reference model, model mappings, generic matchmakers and matchmaking techniques. Finally, MAGDA is used to support the definition and use of three different discovery solutions
ARTEMIS: A Process Modeling and Analysis Tool Environment
No full textTo support business process understanding and reengineering, techniques and tools for process modeling and analysis are required. The paper presents the ARTEMIS tool environment for business process modeling and analysis. Process analysis is performed according to an organizational structure perspective and an operational structure perspective, to capture the degree of autonomy/dependency of organization units in terms of coupling, and the inter-process semantic correspondences, in terms of data and operation similarity, respectively. Processes are modeled as workflows and techniques developed for workflow analysis are presented in the context of a pilot application involving the Italian Ministry of Justic
Straightforward heterogeneization of Cu(I) complexes of chiral pyridine containing macrocyclic ligands (Pc-L*) and their applications to cyclopropanation reactions
No full textWe have recently reported that copper(I) complexes of the new C1-symmetric pyridine-based 12 membered tetraaza macrocyclic (Pc-L*) ligands are competent catalysts in the enantioselective cyclopropanation of olefins employing ethyl diazoacetate (EDA) as carbene precursor.1 Heterogeneous single site catalysts in many cases show superior performances in terms of activity, selectivity and reciclability coupling together the advantages of heterogeneous and homogeneous systems.2 We report here preliminary results on the heterogeneization of our system. Cu(I) complexes (see fig), based on functionalised pyridine-containing macrocyclic chiral ligands were heterogeneized on mesoporous ordered and non-ordered silicas (Davisil, MCM-41, etc.) by the SHB method.2 Materials obtained were fully characterized for metal content, textural properties, hydrogen bonds between Cu complex and surface silanols by a pool of techniques. Catalysts were tested in enantioselective cyclopropanation of olefins and they showed performances at least comparable to those obtained with the homogeneous counterpart. Tests using both basic and ordered silicas with the aim of exploiting the confinement effect on stereoselectivity are currently in progress.
References
[1] Caselli, A.; Cesana, F.; Gallo, E.; Casati, N.; Macchi, P.; Sisti, M.; Celentano, G.; Cenini, S.. Dalton Trans. 2008, 4202. [2] C. Bianchini, P. Barbaro, V. Dal Santo, R. Gobetto, A. Meli, W. Oberhauser, R. Psaro, F. Vizza, Adv. Synth. Catal., 2001, 343, 41-45
Platinum/Palladium hollow nanofibers as high-efficiency counter electrodes for enhanced charge transfer
No full textPt/Pd hollow nanofibers were obtained by sputtering a Pt/Pd alloy (80/20 wt%) onto polymer nanofibers (used as sacrificial template) and were used as counter-electrodes (CEs) in dye-sensitized solar cells (DSSCs). We demonstrate that optimization of nanofiber density and Pt/Pd sputtering thickness can increase the short circuit current density and consequently lead to a ∼15% enhancement in power conversion efficiency (PCE), when compared to the commonly used flat Pt/Pd CEs with the same thickness. The processes that contribute to such PCE improvement are: (i) increased surface area provided by the high aspect ratio hollow nanofibers and (ii) improved electro-catalytic performance, as validated by electrochemical impedance spectroscopy (EIS) measurements. The latter showed a two-fold decrease in the charge-transfer resistance of the nanostructured-CE, compared to the flat CE. The contribution of the Pt/Pd hollow nanofiber to light scattering was negligible as shown by reflectance measurements. These results suggest a simple and straightforward strategy to increase PCE in DSSCs, to minimize the use of precious metals used in this kind of devices and, more generally, to tailor the CE structure in photoelectrochemical systems to boost their functional properties, thanks to the advantages afforded by this complex morphology
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