434 research outputs found
From learning to partnership : multinational research and development cooperation in developing countries
The authors analyze the determinants of interfirm agreements between industrial and developing countries for research and development (R&D) - that is, between firms with asymmetric endowments of knowledge. They develop a model in which a multinational has two options: a) setting up a subsidiary and competing with a local firm in a duopoly, or b) implementing an agreement and sharing monopoly profits. The two firms, if they chose the agreement, may also cooperate in R&D. The model shows that: a) the choice of cooperating in R&D is influenced by the intertemporal preferences of the developing country firm, the relative efficiency in R&D of the two firms, and the extent of knowledge spillovers; and b) the choice of cooperating R&D increases both the profitability and stability of the agreement. The empirical analysis is based on a data set of international arm's length agreements, part of which involve joint R&D. Testing the two-choice model supports some of the key theoretical results and assumptions. R&D agreements are particularly likely to emerge when firms are operating in knowledge-intensive industries, when the partners have a nonhierarchical contractual relationship, and when technological asymmetries between home and host countries exist but are not too great.Economic Theory&Research,Agricultural Knowledge&Information Systems,Scientific Research&Science Parks,Environmental Economics&Policies,Small and Medium Size Enterprises,Economic Theory&Research,Environmental Economics&Policies,Scientific Research&Science Parks,Science Education,Agricultural Knowledge&Information Systems
Magnetic properties of epsilon iron(III) oxide nanorod arrays functionalized with gold and copper(II) oxide
A sequential chemical vapor deposition (CVD) - radio frequency (RF)-sputtering approach was adopted to fabricate supported nanocomposites based on the scarcely investigated \u3b5-iron(III) oxide polymorph. In particular, \u3b5-Fe2O3 nanorod arrays were obtained by CVD, and their subsequent functionalization with Au and CuO nanoparticles (NPs) was carried out by RF-sputtering under mild operational conditions. Apart from a multi-technique characterization of material structure, morphology and chemical composition, particular efforts were dedicated to the investigation of their magnetic properties. The pertaining experimental data, discussed in relation to the system chemico-physical characteristics, are directly dependent on the actual chemical composition, as well as on the spatial distribution of Au and CuO nanoparticles. The approach adopted herein can be further implemented to control and tailor different morphologies and phase compositions of iron oxide-based nanomaterials, meeting thus the open requests of a variety of technological utilizations
Is Rust a Real Must? From Design to Applications of Multifunctional Fe2O3-based Nanomaterials
The present PhD thesis is devoted to the design and fabrication of multi-functional Fe2O3-based nanomaterials by means of vapor phase techniques, such as chemical vapor deposition, both thermal (CVD) and plasma enhanced (PECVD), atomic layer deposition (ALD) and sputtering, either as such or combined into original preparation strategies.
The performed research activities have covered the entire material production chain, encompassing the preparation of the molecular precursor, the material development and chemico-physical characterization, up to the ultimate functional validation for energy and environmental applications. In particular, the attention has been initially devoted to the synthesis and characterization of a novel Fe(II) precursor [Fe(hfa)2TMEDA (hfa = 1,1,1,5,5,5-hexauoro- 2,4-pentanedionate; TMEDA = N,N,N',N'- tetramethylethylenediamine)], possessing improved properties for use in CVD processes with respect to the iron compounds proposed so far. The utilization of this compound in thermal CVD experiments yielded not only the most stable and widely used α-Fe2O3 phase, but also the rare and scarcely investigated β- and ε-Fe2O3 polymorphs, that could be selectively obtained as pure phases with controlled nano-organization. In addition, Fe(hfa)2TMEDA was used in PECVD experiments as molecular source for both Fe and F thanks to the unique reactivity of non-equilibrium cold plasmas, resulting in the obtainment of F-doped _- and _-Fe2O3 nanosystems. Following the e_orts devoted to the preparation of single-phase nanomaterials with improved functional performances, the fabrication of metal/oxide (M/Fe2O3, with M = Pt, Ag, Au) and oxide/oxide (CuO/Fe2O3, Fe3-xTixO4/Fe2O3) nanocomposites has finally been accomplished through the combination of CVD with sputtering or ALD. The study of the interplay between processing conditions, system features and functional activities was proved to be a successful tool of the whole PhD research activity. To this regard, a thorough characterization of the material composition, morphology and spatial organization, micro- and nano-structure and optical properties, was carried out by the use of forefront and complementary analytical techniques. In addition, the functional performances of selected nanosystems were investigated in view of their possible use in a variety of technological end-uses [magnetism, Li-ion batteries, gas sensing of ammable/toxic analytes, and photo-activated applications (photo-induced hydrophilicity, photocatalytic pollutant decomposition, photocatalytic and photoelectrochemical H2 production)]. The results obtained in this PhD work demonstrate that the preparation of iron(III) oxide systems, either as such or in combination with others guest phases, with selected phase composition (α- or β- or ε-Fe2O3) and nano-organization, represents a valuable answer to meet open challenges in various high-tech applications. In particular, the adopted approaches involving vapour phase-related routes offer the possibility of future up-scaling and commercialization of the studied materials, one of the key issues for their technological exploitation in advanced devices
XPS analysis of Fe2O3-TiO2-Au nanocomposites prepared by a plasma-assisted route
Fe2O3 nanodeposits have been grown on fluorine-doped tin oxide (FTO) substrates by plasma
enhanced-chemical vapor deposition (PE-CVD). Subsequently, the obtained systems have been
functionalized through the sequential introduction of TiO2 and Au nanoparticles (NPs) by means of
radio frequency (RF)-sputtering. The target nanocomposites have been specifically optimized in
view of their ultimate functional application in solar-driven H2 generation. In the present study, our
attention is focused on a detailed X-ray photoelectron spectroscopy (XPS) characterization of the
surface composition for a representative Fe2O3-TiO2-Au specimen. In particular, this report
provides a detailed discussion of the analyzed C 1s, O 1s, Fe 2p, Ti 2p, and Au 4f regions. The
obtained results point to the formation of pure Fe2O3-TiO2-Au composites, with gold present only
in its metallic state and each of the constituents maintaining its chemical identity
A study of Pt-/alpha-Fe2O3 nanocomposites by XPS
alpha-Fe2O3 matrices were deposited on Fluorine-doped Tin Oxide (FTO) substrates by Plasma Enhanced-
Chemical Vapor Deposition (PE-CVD) from Fe(hfa)_2TMEDA (hfa = 1,1,1,5,5,5-hexafluoro-2,4-pentanedionate; TMEDA =
N,N,N’,N’-tetramethylethylenediamine). The obtained nanosystems were subsequently functionalized by platinum nanoparticles (NPs) via Radio Frequency (RF)-sputtering, exposing samples either to a pre- or post-sputtering thermal treatment at 650°C for one hour in air. Interestingly, Pt oxidation state in the final composite systems strongly depended on the adopted processing conditions. In this work, a detailed X-ray Photoelectron Spectroscopy (XPS) analysis was carried out in order to investigate the material chemical composition, with particular regard to the relative Pt(0)/Pt(II)/Pt(IV) content. The obtained results evidenced that, when annealing is performed prior to sputtering, only PtO and PtO2 are revealed in the final Pt/alpha-Fe2O3 nanocomposite. In a different way, annealing after sputtering results in the co-presence of Pt(0), Pt(II) and Pt(IV) species, the former arising from the thermal decomposition of PtO2 to metallic platinum
Comparison of UV, Peracetic Acid and Sodium Hypochlorite Treatment in the Disinfection of Urban Wastewater
One source of water contamination is the release of wastewater that has not undergone
efficient treatment. The aim of this study was to evaluate the reduction obtained with sodium
hypochlorite (NaClO), UV and peracetic acid disinfection treatment of Salmonella spp., pathogenic
Campylobacter, STEC and bacterial indicators in three full-scale municipal wastewater plants. A
general reduction in Salmonella was observed after disinfection, but these bacteria were detected
in one UV-treated sample (culture method) and in 33%, 50% and 17% of samples collected after
NaClO, UV and PAA disinfection treatments, respectively (PCR method). A better reduction was
also observed under NaClO disinfection for the microbial indicators. Independent of the disinfection
treatment, E. coli O157:H7 was not detected in the disinfected samples, whereas some samples treated
with UV and PAA showed the presence of the stx1 gene. No reduction in the presence of stx2 genes
was verified for any of the disinfection treatments. Campylobacter was not detected in any of the
analysed samples. The overall results highlight a better reduction in microbiological parameters with
a NaClO disinfection treatment in a full-scale municipal wastewater plant compared with UV and
PAA. However, the results indicate that a complete and specific monitoring program is necessary to
prevent a possible risk to public health
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