585 research outputs found
One size does not fit all⊠An economic development perspective on the asymmetric impact of Patents on R&D
Innovation is the building block of competitive advantages and thus economic policies are increasingly focused on creating stimulus to increase a countryâs innovative performance and growth potential, namely through knowledge accumulation in general and R&D in particular. In this context, current policy trend seems to support the strengthening of Intellectual Property Rights (IPR), in particular, patent protection, with the argument that positive effects will emerge and would be extensive to all countries regardless their level of development. In this paper we question this âone size fits allâ policy and assess how patent thicket affects knowledge productive investment taking into account countriesâ development levels. Based on a panel of 95 countries over a ten-year period (1997-2006), our results show that patents have asymmetric impacts across countries development stages, evidencing pervious effects on technological leaders and positive ones on some laggards. Such evidence sustains that innovation policies be adjusted to countries development stages.growth models; R&D; patents; economic development
Does Patenting negatively impact on R&D investment?An international panel data assessment
Although the conventional R&D-patents relationship is a long stand and relatively undisputed issue within the innovation literature, the reverse causality, in particular, the potential for a negative impact of patents over R&D has only recently received wide attention boosting interesting (mainly) theoretical debates. The macroeconomic perspective on this issue, however, remains largely unexplored. In fact, no evidence exists that ruled out the possibility of asymmetric effects of patents on R&D in accordance to the level of GDP in general, and to âconvergence clubsâ in particular. Using panel data estimation methods on a sample of 88 countries, over an eight-year period (1996-2003), and controlling for clubs of convergence to account for differences on countriesâ stages of economic development, we found mix support to the negativity of patent on R&D investment. The accumulated patents positively impact on R&D intensity for the set of less developed countries whereas no statistically significant effect emerges in the case of higher developed converge clubs; restricting the highest developed convergence club down to countries with a R&D intensity above 3%, the negativity reverse causality arises, corroborating the asymmetric impact of patents on R&D investment. We further demonstrate that albeit causality appears to be stronger in the most intuitive appealing traditional direction, evidence supports the theoretical conveyed double causality between R&D and Patent.Patents; R&D; panel data; convergence clubs
Searching for clusters in tourism. A quantitative methodological proposal
The tourism industry is one of Europeâs leading employers, and for many regions highly dependent on touristsâ spending, innovation is the difference between growth and stagnation. Thus, at a regional level, tourism may function as a driving force of socioeconomic development and thus contribute to the demise of regional disparities. Such lever effect is usually associated to a geographical concentration abusively denominated of clusters. Most of the studies within the tourism industry identify clusters resorting to simplistic analyses of geographic location measures or expertsâ opinions. These latter tend to neglect the essence of the cluster concept, namely the inter-linkages among regional actors. In the present paper, we propose a methodology to rigorously identify tourism clusters, stressing the importance of networks and cooperation between agents.Clusters; Tourism; Methodology
Enantioselectivity of human AMP, dTMP and UMP-CMP kinases
l-Nucleoside analogues such as lamivudine are active for treating viral infections. Like d-nucleosides, the biological activity of the l-enantiomers requires their stepwise phosphorylation by cellular or viral kinases to give the triphosphate. The enantioselectivity of NMP kinases has not been thoroughly studied, unlike that of deoxyribonucleoside kinases. We have therefore investigated the capacity of l-enantiomers of some natural (d)NMP to act as substrates for the recombinant forms of human uridylate-cytidylate kinase, thymidylate kinase and adenylate kinases 1 and 2. Both cytosolic and mitochondrial adenylate kinases were strictly enantioselective, as they phosphorylated only d-(d)AMP. l-dTMP was a substrate for thymidylate kinase, but with an efficiency 150-fold less than d-dTMP. Both l-dUMP and l-(d)CMP were phosphorylated by UMP-CMP kinase although much less efficiently than their natural counterparts. The stereopreference was conserved with the 2âČ-azido derivatives of dUMP and dUMP while, unexpectedly, the 2âČ-azido-d-dCMP was a 4-fold better substrate for UMP-CMP kinase than was CMP. Docking simulations showed that the small differences in the binding of d-(d)NMP to their respective kinases could account for the differences in interactions of the l-isomers with the enzymes. This in vitro information was then used to develop the in vivo activation pathway for l-dT
A preliminary comparison of the corrosion behaviour of additively and conventionally manufactured 18Ni300 maraging steel for moulds
ABSTRACT: The corrosion behaviour of a maraging steel 18Ni300 manufactured by Laser Powder Bed Fusion (L-PBF) was compared to that of a conventional tool steel. Electrochemical test conditions were chosen to approximate the corrosive environments encountered during injection moulding of polyvinyl chloride (PVC) parts. The corrosion behaviour of the steel produced by both routes was evaluated before and after an ageing treatment at 510 ÂșC for six hours. Cuboid specimens were fabricated and a polished area of 100 mm2 was immersed in a 0.1M HCl solution for 7 days. Open circuit potential (OCP) and polarization curves were used to monitor the material exposed to the corrosive environment. The obtained results indicate that the conventionally produced aged steel is less susceptible to corrosion and that the steel manufactured by L-PBF (not aged condition) showed better resistance to pitting.info:eu-repo/semantics/publishedVersio
Biogas upgrading using shaped MOF MIL-160(Al) by pressure swing adsorption process: Experimental and dynamic modelling assessment
Biogas has been introduced as a sustainable source of energy, which is considered as a promising alternative for conventional fossil fuels. Indeed, biogas requires to be upgraded from the impurities, specifically, carbon dioxide to be commercially utilized. In this study, the potential of shaped form MIL-160(Al) as a water stable Al dicarboxylate microporous MOF has been assessed concerning the biogas upgrading application. To this end, firstly, the dynamic fixed-bed adsorption of carbon dioxide and methane was investigated at 313 K and 4.0 bar. The measured breakthrough outcomes were simulated with a developed mathematical model, which the results confirmed an acceptable potential of model predictions. Afterwards, a pressure swing adsorption (PSA) process with 5-steps was designed relying on dynamic equilibrium results, and experimentally validated by a lab-scale PSA set-up for a 50:50 CO2/CH4 mixture. Finally, an industrial PSA process was designed to have a precise knowledge on the potential of MIL-160(Al) for biogas upgrading for large scale applications. The results demonstrated the purity and recovery of methane around 99 % and 63 %, respectively, which indicated the appealing capacity of this adsorbent for such a purpose.This work was financially supported by LA/P/0045/2020 (ALiCE),
UIDB/50020/2020, and UIDP/50020/2020 (LSRE-LCM), funded by
national funds through FCT/MCTES (PIDDAC). It also received financial
support by national funds through FCT/MCTES (PIDDAC): CIMO, UIDB/
00690/2020 (DOI: 10.54499/UIDB/00690/2020) and UIDP/00690/
2020 (DOI: 10.54499/UIDP/00690/2020); and SusTEC, LA/P/0007/
2020 (DOI: 10.54499/LA/P/0007/2020). Authors also acknowledge
Kyung-Ho Cho and U-Hwang Lee from Korea Research Institute of
Chemical Technology (KRICT), Republic of Korea, for their contributions
in the shaping MIL-160(Al). M. Karimi acknowledges research
grants awarded by Foundation of Science and Technology of Portugal
(FCT) under SFRH/BD/140550/2018 project and University of Porto
under FEUP-BioGasUpGMIL160 project.info:eu-repo/semantics/publishedVersio
Zeolite Beta Membranes for the Octane Upgrading of C5/C6 Light Naphta
The zeolite Beta membranes were prepared by secondary growth method in asymmetric tubular Al2O3 supports (Inocermic GmbH, Germany), combining three different types of seeding techniques and crystallization conditions. Figure 1 show SEM micrographs of a typical non-calcined beta membrane synthesized in this work (cross section view). The vapour permeation experiments performed in the apparatus shown in Figure 2 with mixtures of nHEX, 3MP, 23DMB and 22DMB show that permeate flux increase as the degree of branching decreases following the order: nHEX>>3MP>23DMB>22DMB. Approximately one third of the feed stream cross the membranes. Figure 3 shows that in the retentate stream the fractions of
monobranched and normal hexane isomers (low RON compounds) decrease while the concentration of dibranched isomers (high RON compounds) is increased in relation to the equimolar feed composition.
Consequently, the RON can be boosted in retentate up to 3.8 points. These results demonstrate the potential of the zeolite beta membranes for application in the production of additive-free premium
gasoline
Zeolite Beta membranes for the separation of hexane isomers
The preparation of a-alumina supported zeolite Beta membranes was successfully achieved and sped up
by exploring combinations of three seeding techniques and three synthetic methods. The surface of the
membranes was completely covered by well intergrown crystals; the thickness of the zeolite layers ranged
from 2 to 6 lm depending on the synthesis method used. The quality of the membranes was tested
by means of pervaporation of ethanol/1,3,5-triisopropylbenzene (TIPB) mixtures together with permporometry
experiments. The performance in the vapour separation of quaternary equimolar mixtures of nhexane
(nHEX), 3-methylpentane (3MP), 2,3-dimethylbutane (23DMB) and 2,2-dimethylbutane (22DMB)
in the range 343â443 K showed that permeate flux decreases as the branching degree increases following
the order: nHEX 3MP > 23DMB > 22DMB. In the retentate, the fractions of monobranched and normal
hexane decrease while the concentration of dibranched isomers is increased compared to the feed composition.
The influence of the temperature in the permeation fluxes indicates the existence of an activated
transport mechanism which favours the permeation of more nHEX and 3MP with regard to their
dibranched isomers. The octane number (ON) of the quaternary mixture was enhanced up to 5 points
with the best synthesized membrane
Separation of CO2/N2 onto Shaped MOF MIL-160(Al) Using the Pressure Swing Adsorption Process for Post-combustion Application
Adsorption processes have already been considered as an appealing technology for carbon capture and climate change mitigation. Accordingly, this work investigated the capacity of shaped MIL-160(Al) as a water stable bioderived Al dicarboxylate microporous metal-organic framework for separation of carbon dioxide and nitrogen concerning postcombustion application. First, breakthrough experiments of carbon dioxide and nitrogen were accomplished at 313 K and 4.0 bar. Then, a set of equations/relations were considered to model the dynamic fixed-bed tests, in which the outcomes proved the capacity of the developed model for such a purpose. Next, a pressure swing adsorption (PSA) process with five steps, including pressurization, feed, rinse, blowdown, and purge, was planned and validated using performed experiments in a laboratory-scale PSA setup. In the end, an industrial PSA process was designed to attain a better grasp of the capacity of MIL-160(Al) for postcombustion application. The results indicated an exciting potential of this adsorbent for postcombustion carbon capture, with the purity and recovery of carbon dioxide around 67.3 and 99.1%, respectively.This work was financially supported by LA/P/0045/2020
(ALiCE), UIDB/50020/2020, and UIDP/50020/2020
(LSRE-LCM), funded by national funds through FCT/
MCTES (PIDDAC). It also received financial support by
national funds through FCT/MCTES (PIDDAC): CIMO,
UIDB/00690/2020 (DOI: 10.54499/UIDB/00690/2020) and
UIDP/00690/2020 (DOI: 10.54499/UIDP/00690/2020),
and SusTEC, LA/P/0007/2020 (DOI: 10.54499/LA/P/0007/2020). The authors also acknowledge Kyung-Ho Cho
and U-Hwang Lee from the Korea Research Institute of
Chemical Technology (KRICT), Republic of Korea, for their
contributions in the shaping MIL-160(Al). M.K. acknowledges
research grants awarded by the Foundation of Science and
Technology of Portugal (FCT) under SFRH/BD/140550/2018 project and the University of Porto under FEUPBioGasUpGMIL160
project.info:eu-repo/semantics/publishedVersio
Developing pressure swing adsorption process for biogas upgrading using shaped MIL-160(Al)
In this study, regarding the increasing interest on renewable
sources of energy as well as considering the challenges of climate
changes, the potential of shaped MOF MIL-160 (Al) for biogas
upgrading has been evaluated. Accordingly, firstly the
breakthrough assessments of CO2 and CH4 adsorption onto this
sorbents were studied. Afterwards, a pressure swing adsorption
(PSA) process to this end was designed and developed. The results
showed MIL-160(Al) has an excellent potential for biogas
upgrading concerning CO2 and CH4 separation.info:eu-repo/semantics/publishedVersio
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