177,468 research outputs found
Synthesis and characterisation of the amidine complexes trans-[PtCl(NH3) {HN=C(NH2)R}(2)]Cl (R = Me, Ph, CH2Ph) derived from addition of NH3 to the coordinated nitriles in trans-[PtCl2(N CR)(2)]
No full textThe di-nitrile complexes trans-[PtCl2(NCR)(2)] (R = Me, Ph, CH2Ph) react with an excess of gaseous NH3 in CH2Cl2 at -10 degrees C to form, in high yield, the corresponding di-amidine complexes trans-[PtCl(NH3){HN=C(NH2)R}(2)]Cl in which also one chlorine ligand has been displaced by NH3. The H-1 NMR spectra in DMSO showed the formation of different species which were characterized through NOESY, TOCSY and H-1/C-13 heteronuclear correlations as trans-[Pt(NH3){HN=C(NH2)R}(2)(DMSO)]Cl-2 and trans-[PtCl{HN=C(NH2)R}(2)(DMSO)]Cl. (c) 2005 Elsevier B.V. All rights reserved
La filiera aerospaziale: caratteristiche e prospettive per l’Italia e il Mezzogiorno
No full textSpazio e aerospazio sono elementi fondamentali e strategici per un paese, dato il grande impulso alla ricerca scientifica, al
progresso tecnologico e alle capacità di sviluppo e produzione dell’industria nazionale che possono fornire. Questi due contesti
manifestano le loro prime ricadute nell’industria aerospaziale, dunque attraverso la progettazione, produzione,
commercializzazione e manutenzione di aeromobili, veicoli spaziali e attrezzature specifiche associate al settore (Biggiero e
Samarra, 2010).
Nello specifico, l’intera filiera coinvolge coloro che si occupano di R&S, produttori di hardware spaziali (ad esempio veicoli di
lancio, satelliti, stazioni di terra), fornitori di prodotti che interagiscono con le reti satellitari (ad esempio apparecchiature di
navigazione, telefoni satellitari) e servizi finali (ad esempio servizi di radiodiffusione satellitare o servizi di video diretto a casa)
(OECD, 2019). Il fatturato mondiale del settore è stimato in circa 350 miliardi di dollari.
Secondo lo studio di Bolatto e Frigero (2014) su dati OCSE e Eurostat, emerge come il Regno Unito produca un terzo del valore
aggiunto complessivamente generato dal settore aerospaziale in Europa, pari circa a 31,7 miliardi di euro. A seguire vi sono la
Francia, la Germania e l’Italia. In Europa, l’industria aerospaziale è caratterizzata da pochi operatori di grandi dimensioni. Oltre
ad essi, i sistemi produttivi nazionali sono ricchi di una pluralità di piccole e medie imprese che completano la filiera. In Italia, le
imprese con più di 250 addetti (circa il 7,5% dell’industria) generano circa il 90% del valore aggiunto complessivo. Risultati simili
sono ottenuti anche da Regno Unito, Francia e Germania.
Considerando i Paesi OCSE, l’aerospazio si conferma una fonte importante di innovazione: è il primo settore per incidenza della
Ricerca & Sviluppo sul totale del valore aggiunto dell’economia (18,2%), seguito dal settore dell’elettronica e dell’ottica (17,2%) e
dal settore farmaceutico (14,2%)
Interpolation methods to predict the influence of inlet airflow states on desiccant wheel performance at low regeneration temperature
No full textDesign and implementation of the control structure of the PAPRICA-3 processorProceedings of 4th Euromicro Workshop on Parallel and Distributed Processing
No full textX-ray structural characterization of the bis-guanine derivative of a cisplatin analogue having just one proton on each coordinated nitrogen and a head-to-head conformation: [Pt{(+/-)-N,N'-dimethyl-2,3-diaminobutane}(9-ethyl-guanine)2]dinitrate
No full textThe X-ray structural and NMR characterization of a bis-guanine derivative of a cisplatin analogue designed to reduce the rate of the Pt-N7 rotation of the coordinated guanine nucleobases by more than 1-million-fold is reported. The [Pt{(+/-)-Me(2)dab}(9-EtG)(2)](NO3)(2) (Me(2)dab = N,N'-dimethyl-2,3-diaminobutane, 9-EtG = 9-ethyl-guanine) complex crystallizes in the P2(1)/n space group, and the crystal contains a racemic mixture of complex molecules. The data were collected at 120 2 K, and the crystal and molecular structure (comprising one disordered nitrate) were resolved and refined to conventional agreement factors of R1 = 0.0270 and wR2 = 0.0565. The guanine ligands assume the less common head-to-head (HH) orientation, disclosing full details of the intramolecular relationships between cis guanines and between guanine and cis amine. Moreover, an understanding has been gained of the steric factors determining induction of asymmetry (from carbons to adjacent nitrogen atoms) and puckering of the chelate ring (delta or lambda for R,S,S,R or S,R,R,S configurations at the N,C,C,N chelate-ring atoms, respectively) within the Me2dab ligand. The chemical shift separation between H8 signals of the two HT atropisomers and between the two H8 signals of the single HH atropisomer can be explained in terms of canting of the nucleobases relative to the coordination plane and in terms of the different relationships between the H8 proton of one guanine and the shielding zone of the cis guanine. Furthermore, for each configuration of the Me(2)dab ligand (R,S,S,R or S,R,R,S), the NMR data indicate that the handedness of canting is similar for the two guanines in all three (two HT and one HH) conformers (R canting for R,S,S,R and L canting for S,R,R,S configuration
An LCA case study of a thermal insulation panel made of polyester fiber recycled from post consumer PET bottles
No full textBackground, aim, and scope The interest in polyethylene
terephthalate (PET) recycling is quite recent, but it has been
growing steadily over the past few years. In this context,
the aim of this paper is to assess the eco-profile, the energy
savings and the environmental benefits of the use of
recycled raw materials to manufacture products for thermal
insulation of buildings in Italy (i.e., PET bottles postconsumer).
Materials and methods The life cycle analysis is developed
according to ISO 14040/44. In this paper, based on the
LCA, the main types of environmental impact of a thermal
insulation product have been outlined. This study is
specifically focused on polyester nonwovens, produced by
a company located in Italy. The cradle-to-gate life cycle
inventory is performed for the mass of product needed to
give a thermal resistance R of 1(m2 K/W). The calculation
of the impacts is done with SimaPro software. With an
environmental product declaration-oriented approach, a set
of impact categories is used for the classification and
characterisation of the life cycle impact assessment.
Results The results of the impact assessment for 1m2 K/W
of thermal insulation panels made with recycled PET are
then compared with similar products made with virgin PET.
The lower impact associated with the recycled PET for each
category is underlined: the percentage reduction is around
46% in the GWP category. In the production process, the
fiber-spinning phase results as the most relevant in terms of
energy consumption. In addition, the energy saved when
applying the thermal insulation in a building is estimated at
87 MJ/m2 per unit area per year in Rome. All the energy
used during the production of a thermal insulation panel is
recovered in about 2 years.
Conclusions The product shows significantly low environmental
impacts thanks to the use of non-virgin PET, thus
maintaining high mechanical and physical properties. If the
recovery of PET from separate waste collection in Italy
increases, this would reduce the share of waste PET
purchased from foreign countries and would therefore
reduce further the impact of transports for the production
of the thermal insulation panel under investigation
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
Synthesis and structural characterization of isomeric 'lantern-shaped' platinum(III) complexes of formula [Pt-2(PPh3)X{N(H)C(R)O}(4)](NO3)(2) (X = PPh3, H2O)
No full textThe platinum(III) lantern type complexes [Pt-2(PPh3)(2){N(H)C(R)O}(4)](NO3)(2) [R =Me (1), Bu-t (2)], and [Pt-2(H2O)(PPh3)- {N(H)C(Bu-t)O}(4)](NO3)(2) (3) were synthesized and characterized by H-1 NMR and X-ray crystallography (2 and 3). The compounds can give rise to formation of isomers differing for the sets of equatorial donor atoms around each platinum, (NO)-O-3/NO3 orN(2)O(2), and, in the case of N2O2, for the cis or trans geometry. The effect of the anion upon the chemical shifts of NH protons was studied for NO3-, BF4-, and ClO4-. The stability of phosphine axial ligands in the complexes (NO)-O-3/NO3-[Pt-2(PPh3)(2){N(H)C(R)O}(4)](NO3)(2) as a function of the set of donor atoms was also studied. The complex (NO)-O-3/NO3-3 is the fist non-symmetric lantern-type platinum dimer to be characterized by X-ray diffraction. Comparison of the platinum/axial ligand bond distances in different complexes of this type allows to conclude that two factors contribute to the lengthening of axial bonds: the strong trans labilizing effect of the intermetallic bond and the trans-influence of the axial ligand on the second platinum unit
Synthesis and characterisation of the amidine complexes trans-[PtCl(NH3){HN=C(NH2)R}2]Cl (R = Me, Ph, CH2Ph) derived from addition of NH3 to the coordinated nitriles in trans-[PtCl2(NCR)2]
No full text"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
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