Electro-orientation and electrorotation of metal nanowires

The physical mechanisms responsible for the electrical orientation and electrical rotation of metal nanowires suspended in an electrolyte as a function of frequency of the applied ac electric field are examined theoretically and experimentally. The alignment of a nanowire in an ac field with a fixed direction is called electro-orientation. The induced constant rotation of a nanowire in a rotating electric field is called electrorotation. In both situations, the applied electric field interacts with the induced charge in the electrical double layer at the metal-electrolyte interface, causing rotation due to the torque on the induced dipole, and also from induced-charge electro-osmotic flow around the particle. First, we describe the dipole theory that describes electro-orientation and electrorotation of perfectly polarizable metal rods. Second, based on a slender approximation, an analytical theory that describes induced-charge electro-orientation and electrorotation of metal nanowires is provided. Finally, experimental measurements of the electro-orientation and electrorotation of metal nanowires are presented and compared with theory, providing a comprehensive study of the relative importance between induced-dipole rotation and induced-charge electro-osmotic rotation

A PUF-and biometric-based lightweight hardware solution to increase security at sensor nodes

Security is essential in sensor nodes which acquire and transmit sensitive data. However, the constraints of processing, memory and power consumption are very high in these nodes. Cryptographic algorithms based on symmetric key are very suitable for them. The drawback is that secure storage of secret keys is required. In this work, a low-cost solution is presented to obfuscate secret keys with Physically Unclonable Functions (PUFs), which exploit the hardware identity of the node. In addition, a lightweight fingerprint recognition solution is proposed, which can be implemented in low-cost sensor nodes. Since biometric data of individuals are sensitive, they are also obfuscated with PUFs. Both solutions allow authenticating the origin of the sensed data with a proposed dual-factor authentication protocol. One factor is the unique physical identity of the trusted sensor node that measures them. The other factor is the physical presence of the legitimate individual in charge of authorizing their transmission. Experimental results are included to prove how the proposed PUF-based solution can be implemented with the SRAMs of commercial Bluetooth Low Energy (BLE) chips which belong to the communication module of the sensor node. Implementation results show how the proposed fingerprint recognition based on the novel texture-based feature named QFingerMap16 (QFM) can be implemented fully inside a low-cost sensor node. Robustness, security and privacy issues at the proposed sensor nodes are discussed and analyzed with experimental results from PUFs and fingerprints taken from public and standard databases.Ministerio de Economía, Industria y Competitividad TEC2014-57971-R, TEC2017-83557-

Software para la gestión de servicios de Internet comunitario

Aquest projecte té com a objectiu el desenvolupament d’una aplicació web per a la gestió econòmica d’un servei d’Internet Comunitari en una comunitat de propietaris. L’aplicació permetrà la gestió dels usuaris del servei, els costos del servei i l’emissió de rebuts. L’aplicació està desenvolupada en llenguatge Java fent ús de Spring Framework

Manipulación eléctrica de micropartículas y nanopartículas metálicas inmersas en soluciones electrolíticas

En el presente documento se muestran los resultados obtenidos a lo largo de cuatro años de trabajo en una línea de investigación destinada a entender los fenómenos físicos implicados en la manipulación de partículas metálicas usando campos eléctricos alternos, estando las partículas inmersas en una solución electrolítica. Veremos que las causas responsables del movimiento de una partícula metálica en suspensión son las fuerzas eléctricas aplicadas sobre las cargas inducidas en la interfase metal-electrolito. Esta tesis se centra en el estudio de la electrorotación (ROT) y la electroorientación (EO) de microesferas y de nanovarillas con forma cilíndrica. Las esferas usadas eran de titanio y las varillas de plata. La forma en la que se presentan los resultados en esta tesis sigue el orden cronológico en el que se realizaron los experimentos. Primero se analiza la electrorotación de las microesferas de titanio (capítulo 2) y luego se continúa con el estudio teórico y experimental de la electrorotación y la electroorientación de las nanovarillas de plata (capítulos 3 y 4). Se realizaron dos tipos de experimentos de electroorientación. El primer tipo consistió en imponer un campo eléctrico en una dirección fija que formaba un ángulo de 90 o con la dirección del eje de la varilla y se midió el tiempo que tardaba la varilla en orientarse en la dirección del campo. Posteriormente se pensó que una forma más directa de medir la polarización de las varillas sería a través de las fluctuaciones brownianas de su orientación con respecto a la dirección del campo aplicado (capítulo 5). Un método, este último, que requiere voltajes más bajos que los empleados en los experimentos anteriores. En los experimentos con campos de baja frecuencia realizados con las nanovarillas se observó que cuando dos o más varillas estaban próximas entre sí, se producía una interacción entre ellas que, pensamos, podía estar relacionada con los flujos electroosmóticos generados en torno a ellas. Para aclarar esta cuestión se realizaron experimentos con una concentración alta de varillas, con el fin de estudiar su comportamiento colectivo (capítulo 6). Aparte de estos experimentos se llevaron a cabo otros que resultaron infructuosos, como la dielectroforesis con esferas de titanio, o en los que se obtuvieron resultados positivos aunque no definitivos, como aquellos en los que se usó óxido de polietileno (PEO) para tratar de eliminar el flujo electrosmótico en torno a las varillas. Se encontró que el uso de PEO permite realizar experimentos con valores altos para la conductividad sin que las nanovarillas se adhieran al sustrato (Apéndice A). Una parte importante del trabajo durante los cuatro años de investigación como doctorando ha sido el desarrollo de una serie de programas destinados al análisis de los vídeos obtenidos a partir de los experimentos. Estos programas se hicieron con MATLAB y se muestran en el apéndice B

Neoindividualismo sobre el valor de lo individual en una sociedad de masas

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Derecho, leída en 1975.Fac. de DerechoTRUEProQuestpu

Trusted Cameras on Mobile Devices Based on SRAM Physically Unclonable Functions

Nowadays, there is an increasing number of cameras placed on mobile devices connected to the Internet. Since these cameras acquire and process sensitive and vulnerable data in applications such as surveillance or monitoring, security is essential to avoid cyberattacks. However, cameras on mobile devices have constraints in size, computation and power consumption, so that lightweight security techniques should be considered. Camera identification techniques guarantee the origin of the data. Among the camera identification techniques, Physically Unclonable Functions (PUFs) allow generating unique, distinctive and unpredictable identifiers from the hardware of a device. PUFs are also very suitable to obfuscate secret keys (by binding them to the hardware of the device) and generate random sequences (employed as nonces). In this work, we propose a trusted camera based on PUFs and standard cryptographic algorithms. In addition, a protocol is proposed to protect the communication with the trusted camera, which satisfies authentication, confidentiality, integrity and freshness in the data communication. This is particularly interesting to carry out camera control actions and firmware updates. PUFs from Static Random Access Memories (SRAMs) are selected because cameras typically include SRAMs in its hardware. Therefore, additional hardware is not required and security techniques can be implemented at low cost. Experimental results are shown to prove how the proposed solution can be implemented with the SRAM of commercial Bluetooth Low Energy (BLE) chips included in the communication module of the camera. A proof of concept shows that the proposed solution can be implemented in low-cost cameras.España, Ministerio de Ciencia e Innovación TEC2014-57971-R TEC2017-83557-

El flamenco: origen, historia y lengua. El Flamenco Festival London

Universidad de Sevilla. Grado en Turism

Relevance of particle size distribution to kinetic analysis: the case of thermal dehydroxylation of kaolinite

Kinetic models used for the kinetic analysis of solid-state reactions assume ideal conditions that are very rarely fulfilled by real processes. One of the assumptions of these ideal models is that all sample particles have an identical size, while most real samples have an inherent particle size distribution (PSD). In this study, the influence of particle size distribution, including bimodal PSD, in kinetic analysis is investigated. Thus, it is observed that PSD can mislead the identification of the kinetic model followed by the reaction and even induce complex thermoanalytical curves that could be misinterpreted in terms of complex kinetics or intermediate species. For instance, in the case of a bimodal PSD, kinetics is affected up to the point that the process resembles a reaction driven by a multi-step mechanism. A procedure for considering the PSD in the kinetic analysis is presented and evaluated experimentally by studying the thermal dehydroxylation of kaolinite. This process, which does not fit any of the common ideal kinetic models proposed in the literature, was analyzed considering PSD influence. However, when PSD is taken into account, the process can be successfully described by a 3-D diffusion model (Jander’s equation). Therefore, it is concluded that the deviations from ideal models for this dehydroxylation process could be explained in terms of PSD.Ministerio de Economía y Competitividad CTQ2017-83602- C2-1-RJunta de Andalucía P18-FR-1087, US-1262507, DOC_0004