Numerical analysis of the influence of vortex acoustic flows on the efficiency of agglomeration

It is known and experimentally proven many times that ultrasonic vibrations in the gas phase contribute to the appearance of stationary acoustic flows. Since the flows are caused by energy losses during absorption of oscillations, and they do work against the frictional forces that cause this absorption, then these flows have a vortex character. According to numerous studies and developments in the field of inertial dust separation, at a centripetal acceleration of 10 m/s2 or more, local compaction of particles is observed near the periphery of the vortex flow. Due to this, particles are captured in existing devices based on the inertial dust separation principle. In this regard, the article presents the results of theoretical studies of the potential for the use of acoustic flows for a local increase in the concentration of particles and, consequently, an increase in the efficiency of agglomeration. A model of the influence of vortex acoustic flows on the efficiency of agglomeration is proposed. As a result of the numerical analysis of the model, the fundamental possibility of a significant (more than 4 times) increase in the efficiency of ultrasonic agglomeration of submicron particles due to the formation of vortex acoustic flows in the resonant intervals was revealed.

Iterative Solution of Linear Matrix Inequalities for the Combined Control and Observer Design of Systems with Polytopic Parameter Uncertainty and Stochastic Noise

Most research activities that utilize linear matrix inequality (LMI) techniques are based on the assumption that the separation principle of control and observer synthesis holds. This principle states that the combination of separately designed linear state feedback controllers and linear state observers, which are independently proven to be stable, results in overall stable system dynamics. However, even for linear systems, this property does not necessarily hold if polytopic parameter uncertainty and stochastic noise influence the system’s state and output equations. In this case, the control and observer design needs to be performed simultaneously to guarantee stabilization. However, the loss of the validity of the separation principle leads to nonlinear matrix inequalities instead of LMIs. For those nonlinear inequalities, the current paper proposes an iterative LMI solution procedure. If this algorithm produces a feasible solution, the resulting controller and observer gains ensure robust stability of the closed-loop control system for all possible parameter values. In addition, the proposed optimization criterion leads to a minimization of the sensitivity to stochastic noise so that the actual state trajectories converge as closely as possible to the desired operating point. The efficiency of the proposed solution approach is demonstrated by stabilizing the Zeeman catastrophe machine along the unstable branch of its bifurcation diagram. Additionally, an observer-based tracking control task is embedded into an iterative learning-type control framework.

The Crisis

This chapter offers a comprehensive account of the European Central Bank’s (ECB) actions in the early phases of the financial crisis. We show how, despite stubborn inflation pressures, the ECB responded effectively to post-Lehman shock, inter alia by quantifying the effect of moving to ‘fixed rate with full allotment’ lending in regular and longer-term operations. We nonetheless demonstrate that the potency of this response was partially constrained by the ECB’s ‘passive’ approach to liquidity provision—which hinged on demand from banks—and the ‘separation principle’ between interest rate decisions and liquidity operations. We lay out how these principles began to dissolve with the launch of the ECB’s first bond-buying programmes—the Securities Market Programme in 2010 and the Outright Monetary Transactions programme in 2012—and quantify the effects of these measures. In particular, we document the sequence of events that led up to President Draghi’s famous ‘whatever it takes’ announcement.

Administrative Mode Innovation from the Perspective of Media Convergence:A Case Study of the Administrative Documents

This paper starts with the introduction of concepts of social media and its basic forms. Then it lists out social media’s different features and current situation of administrative documents. Then, to help readers to have better understanding of administrative documents, this paper introduces three functions of administrative documents. After taking a look at social media and administrative documents, the paper shifts its focus to Wechat and Facebook. First, it introduces Wechat’s development and status in the social media age, and then gives the understanding of administrative documents through Facebook and Wechat channels, and at last introduces three functions of administrative documents involving new principles of Separation Principle, Reprinting Principle and Moral Bottom Line Principle. Based on some researches about advertorial traditional writing principles, the paper lists following scholars’ views as comparison of the new principles. As in the age of new media, most active users of mobile devices and services are making good use of reprinting principle, for there are a lot of new articles created every day, and some of which may match the targets of your own administrative documents. The last principle emphasizes on moral issues, which calls for practitioners’ self-discipline to respect intellectual property and etiquette.

Optimal filtering and control of network information epidemics

In this article, we propose an optimal control scheme for information epidemics with stochastic uncertainties aiming at maximizing information diffusion and minimizing the control consumption. The information epidemic dynamics is represented by a network Susceptible-Infected-Susceptible (SIS) model contaminated by both process and observation noises to describe a perturbed disease-like information diffusion process. To reconstruct the contaminated system states, we design an optimal filter which ensures minimized estimation errors in a quadratic sense. The state estimation is then utilized to develop the optimal controller, for which the optimality of the closed-loop system is guaranteed by a separation principle. The designed optimal filter and controller, together with the separation principle, form a complete solution for the optimal control of network information epidemics with stochastic perturbations. Such optimal-filtering-based control strategy is also generalizable to a wider range of networked nonlinear systems. In the numerical experiments on real network data, the effectiveness of the proposed optimal control is validated and confirmed.