This work describes results comparing the influence of surface treatments (grinding, immersion in 20% HNO, solution, anodization in sulphuric acid, and exposure to laboratory air) on the ...characteristics of passive films of AIS1304 stainless steel.
The properties of passive layers in neutral aqueous solutions were investigated using electrochemical impedance spectroscopy (EIS) and surface analysis (AES). The impedance of the system is characterized by one capacitive loop in the 1mHz-100KHz frequency range. The stability of the passive film as a function of surface treatments is investigated.
Two linear optimal control laws and a non‐linear control strategy are critically evaluated. They are implemented in a ten‐story frame structure. For the linear control laws, both an active bracing ...system and a hybrid mass damper are considered as control devices, while the non‐linear control law can be implemented with either an active or semi‐active bracing system. The active and semi‐active systems are compared to a passive bracing system with linear viscous dampers and to a hybrid system consisting of a passive bracing and a hybrid mass damper. Dimensionless indices based on the reduction of the maximum story drift and on the maximum control force required are introduced to compare the efficiencies of different control strategies. While the linear optimal control laws exhibit an excellent performance, the non‐linear control law, in addition to its simplicity and robustness, appears to be more efficient when the allowable control force is within a certain limit. Furthermore, one attractive feature of the latter is that it can be implemented with semi‐active devices to minimize the power requirement.
Résumé. Dans une optique disciplinaire de la gouvernance, cet article propose un cadre d'analyse des contributions du comité d'audit, en termes de qualité du processus d'audit d'une part (effets ...indirects), et de qualité de l'information financière publiée d'autre part (effets directs). Une revue approfondie de la recherche empirique nous permet alors d'évaluer les principaux leviers d'action des comités d'audit, ainsi que les conditions d'efficacité de ces organes. Dans les grandes lignes, il ressort qu'un comité d'audit indépendant contribue souvent à la qualité de l'audit externe et à la fiabilité des données comptables (avec des nuances) ; et que l'expertise financière du comité stimule la fiabilité du contrôle interne et la pertinence des états financiers. Indépendance et expertise apparaissent alors comme des attributs importants et complémentaires à l'efficacité du comité d'audit. Les limites et prolongements possibles de ce courant de recherche sont discutés.
Résumé. Dans une optique disciplinaire de la gouvernance, cet article propose un cadre d'analyse des contributions du comité d'audit, en termes de qualité du processus d'audit d'une part (effets ...indirects), et de qualité de l'information financière publiée d'autre part (effets directs). Une revue approfondie de la recherche empirique nous permet alors d'évaluer les principaux leviers d'action des comités d'audit, ainsi que les conditions d'efficacité de ces organes. Dans les grandes lignes, il ressort qu'un comité d'audit indépendant contribue souvent à la qualité de l'audit externe et à la fiabilité des données comptables (avec des nuances) ; et que l'expertise financière du comité stimule la fiabilité du contrôle interne et la pertinence des états financiers. Indépendance et expertise apparaissent alors comme des attributs importants et complémentaires à l'efficacité du comité d'audit. Les limites et prolongements possibles de ce courant de recherche sont discutés.
The objective of this thesis is threefold. First, it is to research the applicability feedforward networks for identification and linearization of dynamical systems. Second, it is to study the best ...approximation property of feedforward networks and to develop methods for calculating the network parameters that achieve this property. I have developed methods which can be used to evaluate the network responses using the infinity norm as opposed to the 2-norm commonly used in standard training methods. Third, it is to gain insight into the structural problems of feedforward networks such as estimating the required number of nodes and training the interconnection weights based on a given input-output data.
The effect of molybdate ions on the corrosion of Fe in neutral solutions was investigated by electrochemical measurements (d.c. polaristaion and impedance spectroscopy) together with gravimetric ...determinations. Studies were conducted in solutions containing sodium hydrogen/sodium sulphate salts with molybdate concentrations ranging between 10 exp -4 and 10 exp -2 M at pH 8 and 9. Mass loss measurements indicated that approx10 exp -3 M of molybdate was necessary in order to inhibit completely the corrosion of Fe at room temperature. The potentiodynamic polarisation and electrochemical impedance studies gave indications about the mechanism of action of the MoO sub 4 exp 2- ion. They also showed that the inhibiting effect of the oxyanion is increased in the presence of dissolved oxygen. Spontaneous passivation of the corroding Fe electrode could happen only in the presence of dissolved oxygen at concentrations > 10 exp -4 M. However, passivity was also obtained under potentiodynamic polarisation conditions in deaerated solutions. The effect of the oxygen was attributed to displacement of the corrosion potential into the region of self passivation of the steel. Finally, the results indicated that the corrosion inhibition of Fe in neutral solutions by molybdate ions was largely insensitive to pH over the range from 8-9.
We present evidence for the exotic charged charmoniumlike state $Z_{c}^{±}(3900)$ decaying to $J/ψπ^±$ in semi-inclusive weak decays of $b$-flavored hadrons. The signal is correlated with a parent ...$J/ψπ^+ π^-$ system in the invariant-mass range 4.2–4.7 GeV that would include the exotic structure $Y(4260)$. The study is based on $10.4 fb^{−1}$ of $p\bar{p}$ collision data collected by the D0 experiment at the Fermilab Tevatron collider.
We present a measurement of the effective weak mixing angle parameter $\sin^2\theta_\text{eff}^{\ell}$, in $p\bar{p}\rightarrow Z/\gamma^* \rightarrow \mu^+\mu^-$ events at a center of mass energy of ...1.96 TeV, collected by the D0 detector at the Fermilab Tevatron Collider and corresponding to 8.6 fb$^{-1}$ of integrated luminosity. The measured value of $\sin^2\theta_\text{eff}^{\ell}\mu\mu=0.23016 \pm 0.00064$ is further combined with the result from the D0 measurement in $p\bar{p}\rightarrow Z/\gamma^{*}\rightarrow e^{+} e^{-}$ events, resulting in $\sin^2\theta_\text{eff}^{\ell} \text{comb.}=0.23095 \pm 0.00040$. This combined result is the most precise measurement from a single experiment at a hadron collider and is the most precise determination using the coupling of the $Z/\gamma^*$ to light quarks.
We present a measurement of top quark polarization in $t \overline{t}$ pair production in $p \overline{p}$ collisions at $\sqrt{s}$ = 1.96 TeV using data corresponding to 9.7 fb$^{-1}$ of integrated ...luminosity recorded with the D0 detector at the Fermilab Tevatron Collider. We consider final states containing a lepton and at least three jets. The polarization is measured through the distribution of lepton angles along three axes: the beam axis, the helicity axis, and the transverse axis normal to the tt¯ production plane. This is the first measurement of top quark polarization at the Tevatron using lepton+jet final states and the first measurement of the transverse polarization in $t \overline{t}$ production. The observed distributions are consistent with standard model predictions of nearly no polarization.
