Neural network adaptive control for a class of nonlinear uncertain dynamical systems with asymptotic stability guarantees.

In this paper, a neuroadaptive control framework for continuous- and discrete-time nonlinear uncertain dynamical systems with input-to-state stable internal dynamics is developed. The proposed framework is Lyapunov based and unlike standard neural network (NN) controllers guaranteeing ultimate boundedness, the framework guarantees partial asymptotic stability of the closed-loop system, that is, asymptotic stability with respect to part of the closed-loop system states associated with the system plant states. The neuroadaptive controllers are constructed without requiring explicit knowledge of the system dynamics other than the assumption that the plant dynamics are continuously differentiable and that the approximation error of uncertain system nonlinearities lie in a small gain-type norm bounded conic sector. This allows us to merge robust control synthesis tools with NN adaptive control tools to guarantee system stability. Finally, two illustrative numerical examples are provided to demonstrate the efficacy of the proposed approach.     

Mobility study of amorphous polymers by high-resolution NMR at solid-state

Summary Mobility of amorphous polymers such as poly(vinyl chloride) (PVC), atactic polypropylene (PPA) and ethylene-propylene-diene terpolymer (EPDM) were studied by proton spin-lattice relaxation time (T₁ H), proton spin-lattice relaxation time in the rotating frame (T₁H), and dipolar dephasing pulse sequence. The data are discussed in terms of mobility and by the distribution of configurational sequences.     

A Patent Review on the Therapeutic Application of Monoclonal Antibodies in COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) contains spike proteins that assist the virus in entering host cells. In the absence of a specific intervention, efforts are afoot throughout the world to find an effective treatment for SARS-CoV-2. Through innovative techniques, monoclonal antibodies (MAbs) are being designed and developed to block a particular pathway of SARS-CoV-2 infection. More than 100 patent applications describing the development of MAbs and their application against SARS-CoV-2 have been registered. Most of them target the receptor binding protein so that the interaction between virus and host cell can be prevented. A few monoclonal antibodies are also being patented for the diagnosis of SARS-CoV-2. Some of them, like Regeneron^® have already received emergency use authorization. These protein molecules are currently preferred for high-risk patients such as those over 65 years old with compromised immunity and those with metabolic disorders such as obesity. Being highly specific in action, monoclonal antibodies offer one of the most appropriate interventions for both the prevention and treatment of SARS-CoV-2. Technological advancement has helped in producing highly efficacious MAbs. However, these agents are known to induce immunogenic and non-immunogenic reactions. More research and testing are required to establish the suitability of administering MAbs to all patients at risk of developing a severe illness. This patent study is focused on MAbs as a therapeutic option for treating COVID-19, as well as their invention, patenting information, and key characteristics.     

Adaptive Dynamic Inversion for Nonaffine-in-Control Uncertain Systems via Time-Scale Separation. Part II

This paper presents an adaptive dynamic inversion method for uncertain nonaffine-in-control dynamical systems. Online approximation of the adaptive dynamic inversion controller is performed using time-scale separation. The resulting control signal is sought as a solution of a “fast” dynamical equation, which inverts a series-parallel model, whose state is shown to track the state of the original nonaffine-in-control system. The design methodology is constructive, and numerically verifiable sufficient conditions on the system parameters are given. A simulation example, motivated by aerospace applications, illustrates the theoretical results.      

Characterization of EPDM/atactic polypropylene blends by high-resolution solid-state NMR

The study of EPDM/atactic polypropylene blend compatibility was investigated by cross-polarization/magic angle spinning carbon-13 NMR spectra, variation contact time experiment analysis, proton spin-lattice relaxation time in the rotating frame, carbon-13 spin-lattice relaxation time, and a dipolar dephasing experiment. The data are discussed in terms of mobility and compatibility of polymeric blends. © 1996 John Wiley & Sons, Inc.     

A new way to define better improvement options of existing buildings for energy saving

This work proposes a new methodology that is based on the ISO 13790 standard and the Monte Carlo method, which helps obtain the probability density function of the energy consumption in real buildings. The energy consumption under different improvement processes for each building was modelled considering variables such as thermal inertia, number of air changes and number of occupants. Some types of modifications, which are common and basic, were found to exert a clear effect over building energy consumption but these were not exactly defined by recommendations of most of the standards. Its effect was mostly due to the two parameters – the number of occupants and the number of air changes. These results should be considered in future during development of new standards for the purpose of defining the optimal amount of building energy consumption.     

Behavior of the refractive index of lithium disilicate glass ceramic processed at high pressure and high temperature

The aim of this work was to investigate the effect of high pressure and high temperature on the refractive index of lithium disilicate glass ceramic with the stoichiometric composition Li₂O·2SiO₂ (LS₂). A first group of monolithic LS₂ glass samples were processed at 2.5 GPa, 4 GPa and 7.7 GPa at room temperature and a second group was submitted to high pressure and, simultaneously, to heat treatments for nucleation and growth of the crystalline phases. For comparison, samples submitted to the same heat treatments at 1 atm were also investigated. The refractive index of the samples was obtained by spectral ellipsometry and the results were clearly dependent on the particular pressure and temperature conditions. The crystallization of the samples was investigated by X-ray diffraction. For the samples processed under high temperature at 1 atm and at 2.5 GPa a fraction of the originally amorphous glass was transformed to a monoclinic phase of lithium disilicate. For the samples processed under high temperature and at 4 GPa, a large fraction of the originally amorphous glass transformed to an orthorhombic phase while, at 7.7 GPa, it was observed the formation of lithium metasilicate.     

Nonlinear robust control and minimax team problems

The problem of robust stabilization of a linear system leads to the classical ℋ︁_∞ control problem. The same analysis applied to a nonlinear system leads to the problem of ensuring via output feedback that a nonlinear operator be Lipshitz continuous, with a prescribed Lipshitz modulus. We show that, in the same way as the ℋ︁_∞ control problem is equivalent to a minimax control problem, the Lipshitz modulus control problem can be approached via a minimax team decision problem. This motivates us to re-visit a class of the so-called ‘static’ team decision problems for nonlinear dynamical control systems. Because of the ‘static’ character, signaling plays no role in that case, which is important for the equivalence with the Lipshitz modulus control problem. We show that under some conditions, a certainty equivalence principle applies that yields a practical solution to the team problem at hand. To reach that conclusion we must first investigate a ‘partial team’ problem where one of the team members has all the information. Copyright © 1999 John Wiley & Sons, Ltd.     

Carbon-13 assignments of EPDM/PP atactic blends by DEPT and HETCOR

The structure of the elastomeric ethylene–propylene–diene terpolymer/atactic polypropylene (EPDM/PPA) blends were assigned by NMR using DEPT (distortionless enhancement by polarization transfer) and HETCOR (heteronuclear correlation) sequences. These methods were carried out to elucidate solid-state ¹³C-NMR assignments of polymeric blends. © 1996 John Wiley & Sons, Inc.