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showing 10 items of 1967 documents
Dynamic shakedown of structures with variable appended masses and subjected to repeated excitations
1996
Elastic shakedown for discrete, or finite-element discretized, structures subjected to combinations of static and time-variable loads is addressed in the hypothesis of elastic-perfectly plastic material behavior. The static load is conceived as the weight of an additional mass appended to the structure, whereas the time-variable load is conceived as an unknown sequence of excitations belonging to a specified domain, with intervals between subsequent excitations during which the structure is considered as being motionless. It is shown that, in the plane of the static and time-variable load parameters, the structure's dynamic shakedown domain is nonconvex and that its boundary curve generally…
Damping effect on the ITER vacuum vessel displacements during slow downward locked and rotating asymmetric vertical displacement events
2018
Abstract In this paper, we present the electromechanical coupled analysis of the ITER vacuum vessel in case of slow downward locked and rotating Asymmetric VDEs. The numerical model for simulating the AVDE includes the asymmetric distribution of the halo currents obtained by a suitable 3D kink perturbation of a slow VDE downward computed by the 2D code DINA. In the case of a rotational AVDE, the rotation frequency of the kink asymmetry has been chosen to be ω = 2π × 5 rad/s. The model includes the mesh of the main passive components facing the plasma. The whole torus (360 degrees) has been discretized. It is shown that the very high complexity of the numerical model can be suitably treated.…
A resilient distributed measurement system for smart grid application
2020
Since the production of energy from renewable energy sources is strongly increasing, the migration from the classical electric grid toward the smart grid is becoming a reality. Distribution System Operators, along with the control of the entire network and its stability, need to address the security and the reliability of the communication channels and the data itself. In this paper a solution is proposed to address these issues. It is based on a distributed measurement system that relies on a wireless network as well as a redundant Power Line communication system in order to transfer the electrical measures to a centralized SCADA server. The collected data are used to run a power flow algo…
Decoupled solution of radial and weakly meshed distribution networks through a backward method
2008
A methodology for the analysis of radial or weakly meshed distribution systems supplying voltage dependent loads is developed. The solution process is iterative and, at each step, the loads are simulated by means of impedances. The network is divided into two sub-networks which must be solved separately and sequentially; in the first, named RP-net, only the lines resistances and the loads shunt equivalent resistances are considered; in the second, named XQ-net, only the lines reactances and the shunt equivalent reactances are taken into account. After a brief presentation of the b/f method, which is currently the most commonly used technique to solve distribution networks, the proposed meth…
Enumeration of NKG2C+natural killer cells early following allogeneic stem cell transplant recipients does not allow prediction of the occurrence of c…
2015
The role of Natural killer (NK) cells in the control of cytomegalovirus (CMV) infection in allogeneic stem cell transplant recipients has not been precisely characterized. The current study is aimed at investigating the potential role of NK cells expressing the activating receptor NKG2C in affording protection against the development of CMV DNAemia in patients exhibiting detectable CMV-specific CD8+ T-cell responses early following transplantation. A total of 61 nonconsecutive patients were included in the study. Peripheral levels of CD56brightCD16−/low and CD56dimCD16+ NKG2C+ NK cells and CMV pp65/IE-1-specific IFN-γ-producing CD8+ T-cells were enumerated by flow cytometry at days +30 and …
Datorikas fakultātes docētaju slodžu uzskaites sistēma
2018
Kvalifikācijas darbā tiek iekļauta programmatūras prasību specifikācija (PPS) un programmatūras projektējuma apraksts (PPA) Datorikas fakultātes docētāju slodžu uzskaites sistēmai. Sistēma tika izstrādāta izmantojot Oracle datubāzi un Oracle SQL Developer , Sqlplus kā arī SQL*Loader . Sistēmas mērķis ir atvieglot to kā tiek aprēķinātas pasniedzēju slodzes, pēc kurām arī nosaka, kāds ir konkrētā docētāja atalgojums atkarība no izdarītā darba. Šajā sistēmā ir iespējams arī izmantot meklētaju, lai atrastu informāciju par konkrētu docētāju, kādus kursus pasniedz, cik studentiem māca, cik stundas ir nostrādāts. Autentificētiem lietotājiem arī ir iespējams pievienot jaunus datus, vai nu tas būtu …
Home energy management system : a home energy management system under different electricity pricing mechanisms
2014
Masteroppgave i fornybar energi ENE 500 Universitetet i Agder 2014 Peak demand is a severe problem in the electricity grid and it was solved by supply side management in the past. But nowadays the demand side management sources have drawn attention due to the economic and environmental constraints. Demand side management in the domestic sector can play an important role in reducing the peak demand on the power system network. It can help in reducing stress and overloading on the transmission and distribution lines. In many countries there are various demand response programs implemented for industrial and commercial loads. In these programs load control is primarily achieved by various type…
Catalytic Asymmetric Formal [3+2] Cycloaddition of 2-Isocyanatomalonate Esters and Unsaturated Imines: Synthesis of Highly Substituted Chiral γ-Lacta…
2017
[EN] Unlike their isocyano and isothiocyanato analogues, isocyanato esters remain almost unexplored as formal 1,3-dipoles in asymmetric catalytic reactions. The first asymmetric formal [3+2] cycloaddition involving isocyanato esters and electrophilic alkenes is reported. Diisopropyl 2-isocyanatomalonate reacts with a,b-unsaturated N-(o-anisidyl) imines in the presence of a Mg(OTf)2¿BOX complex to give highly substituted chiral pyrrolidinones featuring a conjugate exocyclic double bond with excellent yields and enantiomeric excesses up to 99%. Several transformations of the resulting heterocycles, including the synthesis of a pyroglutamic acid derivative, have been carried out.
Benzoxetes and Benzothietes ¾ Heterocyclic Analogues of Benzocyclobutene
2012
Benzo-condensed four-ring heterocycles, such as benzoxetes 1 and benzothietes 3 represent multi-purpose starting compounds for the preparation of various higher heterocyclic ring systems. The thermal or photochemical valence isomerizations between the benzenoid forms 1,3 and the higher reactive o-quinoid structures 2,4 provide the basis for the synthetic applications. On the other hand, this valence isomerization impedes in particular the generation and storage of 1 because the thermal equilibrium 1 ⇆ 2 is completely on the side of 2. Thus, the number of erroneous or questionable benzoxete structures published to date is surprisingly high. On the contrary, the thermal equilibrium 3 ⇆ 4 is o…
Scientific power in the Spanish press during the Pandemic : a portrait of new leaders while explaining its risk
2021
This work is based on the mediatisation of society theory, which establishes more attached importance and the presence of the mass media as mediators in various social processes, as well as on Production Studies, that analyse creative skills to draw an audience, to apply these theories to the media representation of the COVID-19 pandemic. The objective is to analyse how the generalist media have represented male/female scientists, who have become social benchmarks during the first COVID-19 wave in Spain. Our initial hypothesis considers that the purpose of the mediatisation of scientific discourse was to contribute answers to, and to keep society calm, in an uncertainty context. By content …