Efecto de la tensión superficial de MXenos de carbono en la captura de CO2

Treballs Finals de Grau de Química, Facultat de Química, Universitat de Barcelona, Any: 2020, Tutors: Francesc Viñes Solana, Ángel Morales GarcíaOne of the major challenges of our nowadays society is the fight against climate change derived from the gradual global warming of the Earth surface due to the high concentration of detrimental greenhouse gases in the atmosphere, such as CO2 or CH4. These gases absorb the radiated heat emitted by the Earth toward space consequently promoting the so-called greenhouse effect. In principle, this effect is beneficial, because it leads to the thermal stability that is essential for life. However, the anthropogenic activity has derived into a great dependency of fossil fuels, especially since the industrial revolution, generating an excessive concentration of the above-mentioned gases, and so increasing the Earth temperature leading as well to the acidification of oceans. Nowadays, the CO2 concentration in the atmosphere has reached 360 ppm, and this amount is expected to be doubled by the end of this century. The direct consequence of such concentration is the increase of the Earth’s temperature, expected to rise 2-5 ºC, leading to the melting of the poles, augmenting the level of the sea, and causing floods and other devastating phenomena across the world. To minimize, even avoid such consequences, new technologies are sought to reduce these greenhouse gases concentrations. The usage of CO2 sweeper derived materials emerges as a suitable technology for Carbon Capture and Storage (CCS). In this context, Transition Metal Carbides (TMCs) materials have been suggested as potential substrates for CO2 capture and activation due to the exothermic CO2 adsorption even at low partial pressures. Interestingly, the two-dimensional counterparts of TMCs, called MXenes, have shown an even better performance for CCS. These MXenes are synthetized by MAX phase precursors exfoliation techniques, thus depending on the MAX phases composition and demanding a certain energy to foster the layers separation. Indeed, such an exfoliation energy could be a descriptor to seize the resulting MXene chemical activity, here analyzed in depth through computational simulations, correlating the CO2 adsorption energies on MXenes with the estimates of exfoliation energie

Networked gain-scheduled fault diagnosis under control input dropouts without data delivery acknowledgement

This paper investigates the fault diagnosis problem for discrete‐time networked control systems under dropouts in both control and measurement channel with no delivery acknowledgment. We propose to use a proportional integral observer‐based fault diagnoser collocated with the controller. The observer estimates the faults and computes a residual signal whose comparison with a threshold alarms the fault appearance. We employ the expected value of the arriving control input for the open‐loop estimation and the measurement reception scenario for the correction with a jump observer. The jumping gains are scheduled in real time with rational functions depending on a statistic of the difference between the control command being applied in the plant and the one being used in the observer. We design the observer, the residual, and the threshold to maximize the sensitivity under faults while guaranteeing some minimum detectable faults under a predefined false alarm rate. Exploiting sum‐of‐squares decomposition techniques, the design procedure becomes an optimization problem over polynomials

Inferential networked control with accessibility constraints in both the sensor and actuator channels

The predictor and controller design for an inferential control scheme over a network is addressed. A linear plant with disturbances and measurement noise is assumed to be controlled by a controller that communicates with the sensors and the actuators through a constrained network. An algorithm is proposed such that the scarce available outputs are used to make a prediction of the system evolution with an observer that takes into account the amount of lost data between successful measurements transmissions. The state prediction is then used to calculate the control actions sent to the actuator. The possibility of control action drop due to network constraints is taken into account. This networked control scheme is analyzed and both the predictor and controller designs are addressed taking into account the disturbances, the measurement noise, the scarce availability of output samples and the scarce capability of control actions update. The time-varying sampling periods that result for the process inputs and outputs due to network constraints have been determined as a function of the probability of successful transmission on a specified time with a Bernoulli distribution. For both designs H∞ performance has been established and LMI design techniques have been used to achieve a numerical solution

Performance Tradeoffs for Networked Jump Observer-Based Fault Diagnosis

Print Request Permissions In this paper, we address the fault diagnosis problem for discrete-time multi-sensor systems over communication networks with measurement dropouts. We use the measurement outcomes to model the measurement reception scenarios. Based on this, we propose the use of a jump observer to diagnose multiple faults. We model the faults as slow time-varying signals and introduce this dynamic in the observer to estimate the faults and to generate a residual. The fault detection is assured by comparing the residual signal with a prescribed threshold. We design the jump observer, the residual and the threshold to attain disturbance attenuation, fault tracking and detection conditions and a given false alarm rate. The false alarm rate is upper bounded by means of Markov's inequality. We explore the tradeoffs between the minimum detectable faults, the false alarm rate and the response time to faults of the fault diagnoser. By imposing the disturbances and measurement noises to be Gaussian, we tighten the false alarm rate bound which improves the time needed to detect a fault. A numerical example is provided to illustrate the effectiveness of the theory developed in the paper

Jump state estimation with multiple sensors with packet dropping and delaying channels

This work addresses the design of a state observer for systems whose outputs are measured through a communication network. The measurements from each sensor node are assumed to arrive randomly, scarcely and with a time-varying delay. The proposed model of the plant and the network measurement scenarios cover the cases of multiple sensors, out-of-sequence measurements, buffered measurements on a single packet and multirate sensor measurements. A jump observer is proposed that selects a different gain depending on the number of periods elapsed between successfully received measurements and on the available data. A finite set of gains is pre-calculated offline with a tractable optimisation problem, where the complexity of the observer implementation is a design parameter. The computational cost of the observer implementation is much lower than in the Kalman filter, whilst the performance is similar. Several examples illustrate the observer design for different measurement scenarios and observer complexity and show the achievable performance

Utilización de excepciones para implementar predicados opacos en técnicas de ofuscación de código intermedio

La plataforma .NET de Microsoft se basa en una filosofía de just-in-time compilation (compilación bajo demanda al momento de la ejecución). Los programas desarrollados de esta manera se ejecutan en un entorno o framework independiente de la plataforma, basado en objetos y, en algunos casos, permitiendo que interactúen componentes desarrollados en distintos lenguajes de programación. La clave de esta flexibilidad se da en que, tanto en JAVA como en las plataformas .NET, la compilación resulta en un código intermedio, independiente de la plataforma (bytecode y MSIL respectivamente). Sin embargo, dicha flexibilidad tiene un costo. Hoy en día, y utilizando herramientas gratuitas que pueden descargarse desde Internet, es sumamente fácil aplicar tecnologías de ingeniería inversa a las dos plataformas de desarrollo más populares: JAVA y .NET. De todas las técnicas que los desarrolladores pueden utilizar para proteger su propiedad intelectual, la ofuscación es la técnica más aceptada y de hecho, es la única utilizada comercialmente. En este trabajo, proponemos el uso de los mecanismos de excepción (bloques try-catch) que brinda la plataforma .NET como una manera de mejorar la calidad de uno de los bloques básicos de la ofuscación, los predicados opacos.Microsoft’s .NET Framework, and JAVA platforms, are based in a just-in-time compilation philosophy. Software developed using these technologies are executed in a hardware independent framework, which provides a full object-oriented environment, and in some cases allows the interaction of several components written in different programming languages. This flexibility is achieved by compiling into an intermediate code which is platform independent. Java is compiled into ByteCode, and Microsoft .NET programs are compiled into MSIL (Microsoft Intermediate Code). However, this flexibility comes with a price. It is really easy, with tools available for free in the web, to decompile this intermediate code and obtain a working, readable version of the original source code. Of all techniques developers can use to protect their intellectual property, obfuscation is the most accepted and commercially available one. In the present work, we propose the use of try-catch mechanisms available in .NET as a way to improve the quality of one of the building blocks of obfuscation: opaques predicates.Red de Universidades con Carreras en Informática (RedUNCI

Using Exception Handling to Build Opaque Predicates in Intermediate Code Obfuscation Techniques

Microsoft's .NET Framework, and JAVA platforms, are based in a just-in-time compilation philosophy. Software developed using these technologies is executed in a hardware independent framework, which provides a full object-oriented environment, and in some cases allows the interaction of several components written in different programming languages. This flexibility is achieved by compiling into an intermediate code which is platform independent. Java is compiled into ByteCode, and Microsoft .NET programs are compiled into MSIL (Microsoft Intermediate Code). However, this flexibility comes with a price. With freeware tools available in Internet, it is quite easy to decompile intermediate codes and obtain a working, readable version of the source code. Obfuscation is the most accepted and commercially available technique that developers can use to protect their intellectual property In this work, we propose the use of try-catch mechanisms available in .NET as a way to improve the quality of one of the building blocks of obfuscation: opaque predicates.Facultad de Informátic

Utilización de excepciones para implementar predicados opacos en técnicas de ofuscación de código intermedio

La plataforma .NET de Microsoft se basa en una filosofía de just-in-time compilation (compilación bajo demanda al momento de la ejecución). Los programas desarrollados de esta manera se ejecutan en un entorno o framework independiente de la plataforma, basado en objetos y, en algunos casos, permitiendo que interactúen componentes desarrollados en distintos lenguajes de programación. La clave de esta flexibilidad se da en que, tanto en JAVA como en las plataformas .NET, la compilación resulta en un código intermedio, independiente de la plataforma (bytecode y MSIL respectivamente). Sin embargo, dicha flexibilidad tiene un costo. Hoy en día, y utilizando herramientas gratuitas que pueden descargarse desde Internet, es sumamente fácil aplicar tecnologías de ingeniería inversa a las dos plataformas de desarrollo más populares: JAVA y .NET. De todas las técnicas que los desarrolladores pueden utilizar para proteger su propiedad intelectual, la ofuscación es la técnica más aceptada y de hecho, es la única utilizada comercialmente. En este trabajo, proponemos el uso de los mecanismos de excepción (bloques try-catch) que brinda la plataforma .NET como una manera de mejorar la calidad de uno de los bloques básicos de la ofuscación, los predicados opacos.Microsoft’s .NET Framework, and JAVA platforms, are based in a just-in-time compilation philosophy. Software developed using these technologies are executed in a hardware independent framework, which provides a full object-oriented environment, and in some cases allows the interaction of several components written in different programming languages. This flexibility is achieved by compiling into an intermediate code which is platform independent. Java is compiled into ByteCode, and Microsoft .NET programs are compiled into MSIL (Microsoft Intermediate Code). However, this flexibility comes with a price. It is really easy, with tools available for free in the web, to decompile this intermediate code and obtain a working, readable version of the original source code. Of all techniques developers can use to protect their intellectual property, obfuscation is the most accepted and commercially available one. In the present work, we propose the use of try-catch mechanisms available in .NET as a way to improve the quality of one of the building blocks of obfuscation: opaques predicates.Red de Universidades con Carreras en Informática (RedUNCI

Co-design of jump estimators and transmission policies for wireless multi-hop networks with fading channels

We study transmission power budget minimization of battery-powered nodes in a remote state estimation problem over multi-hop wireless networks. Communication links between nodes are subject to fading, thereby generating random dropouts. Relay nodes help to transmit measurements from distributed sensors to an estimator node. Hopping through each relay node introduces a unit delay. Motivated by the need for estimators with low computational and implementation cost, we propose a jump estimator whose modes depend on a Markovian parameter that describes measurement transmission outcomes over a finite interval. It is well known that transmission power helps to increase the reliability of measurement transmissions, at the expense of reducing the life-time of the nodes’ battery. Motivated by this, we derive a tractable iterative procedure, based on semi-definite programming, to design a finite set of filter gains, and associated power control laws to minimize the energy budget while guaranteeing an estimation performance level. This procedure allows us to tradeoff the complexity of the filter implementation with performance and energy use.This work has been funded by projects TEC2015-69155-R from MICINN, PI15734, E-2015-15 and P1⋅1B2015-42 from Universitat Jaume I. The material in this paper was not presented at any conference. This paper was recommended for publication in revised form by Associate Editor Hideaki Ishii under the direction of Editor Christos G. Cassandras

Utilización de excepciones para implementar predicados opacos en técnicas de ofuscación de código intermedio

La plataforma .NET de Microsoft se basa en una filosofía de just-in-time compilation (compilación bajo demanda al momento de la ejecución). Los programas desarrollados de esta manera se ejecutan en un entorno o framework independiente de la plataforma, basado en objetos y, en algunos casos, permitiendo que interactúen componentes desarrollados en distintos lenguajes de programación. La clave de esta flexibilidad se da en que, tanto en JAVA como en las plataformas .NET, la compilación resulta en un código intermedio, independiente de la plataforma (bytecode y MSIL respectivamente). Sin embargo, dicha flexibilidad tiene un costo. Hoy en día, y utilizando herramientas gratuitas que pueden descargarse desde Internet, es sumamente fácil aplicar tecnologías de ingeniería inversa a las dos plataformas de desarrollo más populares: JAVA y .NET. De todas las técnicas que los desarrolladores pueden utilizar para proteger su propiedad intelectual, la ofuscación es la técnica más aceptada y de hecho, es la única utilizada comercialmente. En este trabajo, proponemos el uso de los mecanismos de excepción (bloques try-catch) que brinda la plataforma .NET como una manera de mejorar la calidad de uno de los bloques básicos de la ofuscación, los predicados opacos.Microsoft’s .NET Framework, and JAVA platforms, are based in a just-in-time compilation philosophy. Software developed using these technologies are executed in a hardware independent framework, which provides a full object-oriented environment, and in some cases allows the interaction of several components written in different programming languages. This flexibility is achieved by compiling into an intermediate code which is platform independent. Java is compiled into ByteCode, and Microsoft .NET programs are compiled into MSIL (Microsoft Intermediate Code). However, this flexibility comes with a price. It is really easy, with tools available for free in the web, to decompile this intermediate code and obtain a working, readable version of the original source code. Of all techniques developers can use to protect their intellectual property, obfuscation is the most accepted and commercially available one. In the present work, we propose the use of try-catch mechanisms available in .NET as a way to improve the quality of one of the building blocks of obfuscation: opaques predicates.Red de Universidades con Carreras en Informática (RedUNCI