2,346 research outputs found
Elliptic equations with compactly supported solutions
For any p in (1,2) and arbitrary f in L^p(R^2) with compact support, it is proved that there exists a pair (L, u), with L second order uniformly elliptic operator and u in W^{2,p}_0(R^2) such that L u = f a.e. in R^2
Renewable hydrogen supply chains: A planning matrix and an agenda for future research
Worldwide, energy systems are experiencing a transition to more sustainable systems. According to the Hydrogen Roadmap Europe (FCH EU, 2019), hydrogen will play an important role in future energy systems due to its ability to support sustainability goals and will account for approximately 13% of the total energy mix in the coming future. Correct hydrogen supply chain (HSC) planning is therefore vital to enable a sustainable transition, in particular when hydrogen is produced by water electrolysis using electricity from renewable sources (renewable hydrogen). However, due to the operational characteristics of the renewable HSC, its planning is complicated. Renewable hydrogen supply can be diverse: Hydrogen can be produced de-centrally with renewables, such as wind and solar energy, or centrally by using electricity generated from a hydro power plant with a large volume. Similarly, demand for hydrogen can also be diverse, with many new applications, such as fuels for fuel cell electrical vehicles and electricity generation, feedstocks in industrial processes, and heating for buildings. The HSC consists of various stages (production, storage, distribution, and applications) in different forms, with strong interdependencies, which further increase HSC complexity. Finally, planning of an HSC depends on the status of hydrogen adoption and market development, and on how mature technologies are, and both factors are characterised by high uncertainties. Directly adapting the traditional approaches of supply chain (SC) planning for HSCs is insufficient. Therefore, in this study we develop a planning matrix with related planning tasks, leveraging a systematic literature review to cope with the characteristics of HSCs. We focus only on renewable hydrogen due to its relevance to the future low-carbon economy. Furthermore, we outline an agenda for future research, from the supply chain management perspective, in order to support renewable HSC development, considering the different phases of renewable HSCs adoption and market development
Kommerell’s diverticulum and aneurysmal right-sided aortic arch: A case report and review of the literature
AbstractRight-sided aortic arch is a rare variant of the thoracic vascular anatomy that may be accompanied by an aberrant origin of the left subclavian artery. We report a true aneurysm of the distal arch and descending thoracic aorta in a patient with right-sided arch and review previous descriptions of aneurysms of anomalous right-sided aortas. In our patient, the left subclavian artery originated at the junction between the distal arch and the descending thoracic aorta located in the right chest and was aneurysmal (Kommerell’s diverticulum); the thoracic aorta was also aneurysmal. Extra-anatomic left subclavian-to-carotid transposition was performed before the intrathoracic procedure. Subsequently, a right thoracotomy provided adequate exposure for repairing the aortic aneurysm and oversewing the aneurysmal origin of the subclavian artery. Because the distal aortic arch was involved, deep hypothermia and circulatory arrest were used. Only five previous instances of true aneurysms of a right-sided aortic arch have been reported; four of these patients underwent operative repair (via bilateral thoracotomy, median sternotomy, or right thoracotomy). We believe that a right thoracotomy provides good exposure and avoids the morbidity associated with bilateral thoracotomy. The reconstruction of the subclavian artery has not previously been reported in this setting. Performing subclavian reconstruction as an extrathoracic procedure before the intrathoracic repair would be expected to reduce the subsequent risk of distal ischemia or subclavian steal without increasing the overall morbidity associated with the procedure. (J Vasc Surg 2000;32:1208-14.
Harbour water managment for port structures and sea bottom design, coast proximity navigation managment, water quality control.
Tide is a sea level up-down water motion basically depending on three different phenomena: the Earth-Moon-Sun gravitational relationship, the water surface fluid reaction to atmospheric meteorological dynamic action and the Newtonian vertical adjustment of the sea surface due to
atmospheric pressure variations. The first tide component (astro-tide) is periodic and well known in all points of the Earth surface; the second one is directly related to the meteorological phenomenon and then it is foreseeable; the Newtonian component, on the contrary, is not readily predictable by a
general hydrostatic law, because the factor “J” that represents the Newtonian transfer (from the atmospheric weight to the consequent sea level) is variable in each harbour area. A statistical study and the related numerical data interpretation of the measurements performed in the Ports of Genoa,
La Spezia, Marina di Carrara, Livorno, Piombino, Civitavecchia and Ravenna (belonging to the Italian Newtonian Meteotide Network) show port values of Jph (from 1.4-1.6 cm/hPa to > 2 cm/hPa,
on the contrary of the off-shore areas where Jph is about 1 cm/hPa). This phenomenon
(hydrobarometric tide wave) produces even double values of harbour sea level fluctuations amplitude in comparison to astronomic tide sea level oscillations, and is characterized by a wavelength from 8-12 h to same days and a 10-25 days/year as mean temporal occurrence in the Northern Tyrrhenian Sea. This is the most relevant ordinary risk factor for our ports activity and structures design. The present note shows a quantitative method to define the values of Jph factor for ports and its use in the Harbour WaterSide Management (HWSM) based on the joined use of barometers, hydrometers and clocks, the preliminary results related to the use of the gravimeters as hydrobarometric predictor in La Spezia Port and two examples of use of Jph factor in the port management: refloating of a landing ship and optimisation of a dock performance as pleasure boats mooring
External Subsidies and Lasting Peace
Third parties are thought to face a trade-off in that those actions most likely to bring peace in the short run appear least likely to ensure its long-run stability. Yet the trade-off between conflict management and conflict resolution may be overstated. Analyzing an iterated three-player bargaining model with both information and commitment problems, we first demonstrate two conditions under which third parties may produce lasting peace through conditional subsidies, even without addressing underlying informational or commitment problems. Second, we illustrate this possibility by analyzing the impact of US foreign aid on patterns of conflict and peace between Israel and her neighbors. Our analysis indicates that the termination of the rivalry between Israel and Egypt was most likely not brought about by the Camp David accords or peacekeeping operations, but by sustained foreign aid provision. We discuss the implications for both this conflict and conflict management more broadly. </jats:p
Chemical characterization and quantification of titanium dioxide nanoparticles (Tio2-nps) in seafood by single-particle icp-ms: Assessment of dietary exposure
The significant increase in the production and variety of nanoparticles (NPs) has led to their release into the environment, especially into the marine environment. Titanium dioxide nanoparticles (TiO2-NPs) are used in different industrial sectors, from the food industry to several consumer and household products. Since the aquatic environment is highly sensitive to contamination by TiO2-NPs, this work aimed to give a preliminary assessment of the contamination of packaged seafood, where the food additive TiO2 (E171) is not to be intentionally added. This allowed providing a chemical characterization and quantification of TiO2-NPs in processed canned fish products belonging to different trophic positions of the pelagic compartment and in canned clam. The new emerging technique called single-particle inductively coupled plasma mass spectrometry (spICP-MS) was applied, which allows the determination of nanoparticle number-based concentration, as well as the dissolved titanium. This study highlights how processed food, where the pigment E171 was not intentionally added, contains TiO2 in its nanoparticle form, as well as dissolved titanium. Processed clam represented the seafood with the highest content of TiO2-NPs. In pelagic fish species, we found progressively higher levels and smaller sizes of TiO2-NPs from smaller to larger fish. Our results highlight the importance of planning the characterization and quantification of TiO2-NPs in food both processed and not, as well as where the pigment E171 is intentionally added and not, as it is not the only source of TiO2-NPs. This result represents a solid step toward being able to estimate the real level of dietary exposure to TiO2-NPs for the general population and the related health risks
Functional and structural leaf plasticity determine photosynthetic performances during drought stress and recovery in two platanus orientalis populations from contrasting habitats.
In the context of climatic change, more severe and long-lasting droughts will modify the fitness of plants, with potentially worse consequences on the relict trees. We have investigated the leaf phenotypic (anatomical, physiological and biochemical) plasticity in well-watered, drought- stressed and re-watered plants of two populations of Platanus orientalis, an endangered species in the west of the Mediterranean area. The two populations originated in contrasting climate (drier and warmer, Italy (IT) population; more humid and colder, Bulgaria (BG) population). The IT control plants had thicker leaves, enabling them to maintain higher leaf water content in the dry environment, and more spongy parenchyma, which could improve water conductivity of these plants and may result in easier CO2 diffusion than in BG plants. Control BG plants were also characterized by higher photorespiration and leaf antioxidants compared to IT plants. BG plants responded to drought with greater leaf thickness shrinkage. Drought also caused substantial reduction in photosynthetic parameters of both IT and BG plants. After re-watering, photosynthesis did not fully recover in either of the two populations. However, IT leaves became thicker, while photorespiration in BG plants further increased, perhaps indicating sustained activation of defensive mechanisms. Overall, our hypothesis, that plants with a fragmented habitat (i.e., the IT population) lose phenotypic plasticity but acquire traits allowing better resistance to the climate where they became adapted, remains confirmed
Variabilidad GenĂ©tica e IdentificaciĂłn de la Unidad de Manejo de Octopus maya Usando MicrosatĂ©lites EspecĂficos
Developement of real time diagnostics and feedback algorithms for JET in view of the next step
Real time control of many plasma parameters will be an essential aspect in
the development of reliable high performance operation of Next Step Tokamaks.
The main prerequisites for any feedback scheme are the precise real-time
determination of the quantities to be controlled, requiring top quality and
highly reliable diagnostics, and the availability of robust control algorithms.
A new set of real time diagnostics was recently implemented on JET to prove the
feasibility of determining, with high accuracy and time resolution, the most
important plasma quantities. With regard to feedback algorithms, new
model–based controllers were developed to allow a more robust control of
several plasma parameters. Both diagnostics and algorithms were successfully
used in several experiments, ranging from H-mode plasmas to configuration with
ITBs. Since elaboration of computationally heavy measurements is often
required, significant attention was devoted to non-algorithmic methods like
Digital or Cellular Neural/Nonlinear Networks. The real time hardware and
software adopted architectures are also described with particular attention to
their relevance to ITER.Comment: 12th International Congress on Plasma Physics, 25-29 October 2004,
Nice (France
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