Search results for "Ash"

Smart structures through nontraditional design of Tuned Mass Damper Inerter for higher control of base isolated systems

2020

Abstract This paper introduces a smart structure design through the definition of an innovative passive control strategy, referred to as New Tuned Mass Damper Inerter (New TMDI), coupled with a base isolation system (BI), to control displacements in base isolated structures under seismic excitations. The herein proposed New TMDI comprises a recently developed nontraditional Tuned Mass Damper (known as New TMD), in which a secondary mass system is connected to the base plate of the BI system by a spring and to the ground by a dashpot, and of an inerter device placed in parallel with the damper. An optimization procedure which minimizes the base displacement variance of the BI system, conside…

A new methodology for the optimal design of crash-boxes

2014

Multiple-criteria cash-management policies with particular liquidity terms

2019

Abstract Eliciting policies for cash management systems with multiple assets is by no means straightforward. Both the particular relationship between alternative assets and time delays from control decisions to availability of cash introduce additional difficulties. Here we propose a cash management model to derive short-term finance policies when considering multiple assets with different expected returns and particular liquidity terms for each alternative asset. In order to deal with the inherent uncertainty about the near future introduced by cash flows, we use forecasts as a key input to the model. We express uncertainty as lack of predictive accuracy and we derive a deterministic equiv…

'SMART laser', Development of laser sources integrating an optimized functioning via a process of learning

2022

Ost commercially available mode-blocking lasers provide a unique pulse regime to the user, driven only by a simple switch. To solve certain problems, it would be advantageous to increase the possibilities of pulse adjustment in many areas of application, from micro-machining to wavelength conversion. One way to increase the degrees of freedom of a laser cavity is to incorporate into it a saturable absorbant with adjustable parameters, as with non-linear polarization evolution devices (NPEs). The absence of an analytical relationship between the adjustable cavity parameters and the characteristics of a generated pulse can be circumvented by the use of scalable algorithms, well suited to mult…

Synthesis of rigid ethynyl-bridged polytopic picolinate ligands for MOF applications

2015

Abstract Segmented homopolytopic ligands that consist of a rigid central arylene platform, ethynylene spacers, and terminal chelating picolinate subunits have been synthesized in good yields in a two-step procedure involving a Sonogashira-type cross coupling reaction between the ester methyl 5-bromopyridine-2-carboxylate and several arylacetylenes, followed by hydrolysis of the resulting methyl picolinates. A similar strategy has been employed for the preparation of heteroditopic ligands containing picolinate and a second non-chelating pyridine or benzoate unit. The compounds are potential candidates for organic linkers in metal–organic frameworks (MOFs).

Ship-in-a-bottle synthesis of triphenylamine inside faujasite supercages and generation of the triphenylamminium radical ion

2005

Abstract The ship-in-a-bottle synthesis of triphenylamine encapsulated within basic X zeolite has been accomplished by reacting sodium diphenylamide with bromobenzene in the presence of a bifunctional palladium (Hartwig–Buchwald conditions). The presence of incarcerated triphenylamine was demonstrated by dissolving the zeolite with concentrated HF and analyzing the organic material in the dichloromethane extract. Laser flash photolysis (266 nm) gives rise to the generation of triphenylamminium radical cation detected as a transient species decaying in hundreds of microseconds. Upon repetitive cyclic voltammograms, zeolite encapsulated triphenylamine shows a reversible oxidation–reduction pr…

Ferrocenyl (P,N)-diphosphines incorporating pyrrolyl, imidazolyl or benzazaphospholyl moieties: Synthesis, coordination to group 10 metals and perfor…

2013

Abstract Three novel symmetrical ferrocenyl diphosphines with tertiary phosphorus atoms holding respectively nitrogen-containing heterocyclic derivatives of pyrrole, imidazole and benzazaphosphole were synthesized and characterized. Up to now, integration of heteroaromatic fragments, or more generally hetero-cycles, as substituents on the tertiary phosphines of symmetrical ferrocenyl diphosphines has been limited to the furyl motif. Their coordination to palladium and platinum group 10 transition metals was exemplified, and analyzed using single crystal X-ray diffraction. The performances obtained in palladium-catalyzed copper-free Sonogashira and Suzuki cross-coupling reactions using bromo…

Endogenous R&D Symmetry in Linear Duopoly with One-way Spillovers

2005

A duopoly model of cost reducing R&D-Cournot market competition is extended to encompass endogenous timing of R&D investments. Under the assumption that R&D spillovers are zero under simultaneous choices of R&D and only flow from the R&D leader to the follower under sequential choices, sequential and simultaneous play at the R&D stage are compared in order to assess the role of technological externalities in stimulating or attenuating endogenous firm asymmetry. The only timing structure of the R&D stage sustainable as subgame–perfect Nash equilibrium involves simultaneous play and thus zero spillovers.

Interbank lending and the spread of bank failures: A network model of systemic risk

2012

We model a stylized banking system where banks are characterized by the amount of capital, cash reserves and their exposure to the interbank loan market as borrowers as well as lenders. A network of interbank lending is established that is used as a transmission mechanism for the failure of banks through the system. We trigger a potential banking crisis by exogenously failing a bank and investigate the spread of this failure within the banking system. We find the obvious result that the size of the bank initially failing is the dominant factor whether contagion occurs, but for the extent of its spread the characteristics of the network of interbank loans are most important. These results ha…

Determinants of interest margins in Spanish credit institutions before and after the 2008 financial crash

2017

As interest margins of credit institutions affect economic performance of countries, finding out which are the main determinants of their evolution is a research task of great interest at current times. This is the purpose of the present paper as regards to the Spanish case over the period 2004-2012. Based on the econometric contributions by Ho and Saunders (1981) and some of its extensions, the authors develop a model that includes as explanatory variables the factors usually examined in the literature and other singular variables that might be relevant. Particularly, the rate of leverage, the quality of their assets measured according to their risk, and the profit obtained from the sellin…