Experimentation, simulation and analysis of improvised explosive devices-explosively formed projectile

Dentro de los artefactos explosivos improvisados se encuentran aquellos que generan proyectiles formados por explosión, penetradores de blindajes y sistemas acorazados, como los utilizados por grupos insurgentes contra las fuerzas aliadas en zona de operaciones. El objeto de este estudio es reproducir y entender el comportamiento de dichos artefactos explosivos improvisados capaces de generar proyectiles de alta velocidad y gran capacidad de penetración. La comprensión de su comportamiento permitirá mejorar el conocimiento sobre ellos, y por ende, combatirlos de forma más eficaz. Para ello se han realizado los ensayos correspondientes, obteniéndose las primeras caracterizaciones de proyectiles formados por explosión construidos de manera artesanal, tal y como haría un terrorista. Además, se han creado los modelos numéricos correspondientes a cada ensayo, que simulan todo el evento desde su inicio hasta el impacto en el objetivo, recorriendo todos los pasos intermedios. Se han ensayado 3 configuraciones y posteriormente se han simulado, usando el software de análisis por elementos finitos, LS-DYNA® , con una configuración 2 D axisimétrica, con mallados lagrangianos. Los resultados obtenidos por el modelo han alcanzado un alto grado de precisión con relación a los datos experimentales. A partir de aquí se puede concluir que los artefactos explosivos improvisados-proyectiles formados por explosión son una seria amenaza, y que los modelos generados permitirán conocer y ahorrar costes en la lucha contra esta amenaza, y por ende contra el terrorismo, al disponer de un enfoque holístico de la amenaza, y finalmente reducir los costes de la experimentación.Within the category of improvised explosive devices are those that form explosively formed projectiles which penetrate armor and armored systems, such as those used by insurgents against allied forces in operational areas. The purpose of this study is to reproduce and understand the behavior of these improvised explosive devices capable of generating high-velocity, high penetration projectiles. Understanding their behavior will allow for improved knowledge about them, and thus will allow us to more effectively combat them. Thus, the corresponding tests were carried out and the results were obtained from the first characterizations of explosively formed projectiles built using traditional methods, just as a terrorist would have built them. Along with this, numerical models were created for each test simulating the entire event from beginning to impact on the target, including all the intermediate steps. There were three configurations tested and simulated using the software of finite element analysis, LS-DYNA® , a 2-D asymmetric configuration with Lagrangian meshes. The results obtained by the model were compared with data obtained in the experimental tests, yielding a high precision between simulated and tested data. With the data obtained in this study it can be concluded that the improvised explosive devices -explosively formed projectiles is a serious threat. Generated models will allow us to know more about these weapons, to reduce costs in the fight against the threat of improvised explosive devices-explosively formed projectiles and therefore against terrorism with explosively formed projectiles, and to have a holistic approach to the threat and to reduce the cost of experimentation. Minimize the experimental expense.Peer Reviewe

Time-modulated multibeam phased arrays with periodic Nyquist pulses

We present a single sideband time-modulated multibeam phased array governed by periodic Nyquist pulsed signals. A Nyquist pulse is a physically realizable approach to the ideal sinc function. Hence, its low-pass spectrum suits particularly well for time-modulated arrays (TMAs) to perform harmonic beam steering. Contrarily to switched TMAs and standard solutions based on variable phase shifters, the performance and complexity of the proposed time modulation scheme is rather robust when increasing the number of multibeams.Comment: 4 pages, 4 figures, Published in IEEE Antennas and Wireless Propagation Letter

Time-modulated arrays with Haar wavelets

Time-modulated arrays (TMAs) can effectively perform beamsteering over the first positive harmonic pattern by applying progressively delayed versions of stair-step approximations of a sine waveform to the antenna excitations. In this letter, we consider synthesizing such stair-step sine approximations by means of Haar wavelets. Haar functions constitute a complete orthonormal set of rectangular waveforms, which have the ability to represent a given function with a high degree of accuracy using few constituent terms. Hence, when they are applied to the TMA synthesis, employing single-pole double-throw switches, such a feature leads to an excellent rejection level of the undesired harmonics as well as a bandwidth greater than that supported by conventional TMAs with on-off switches.Comment: 5 pages, 4 figures, Published in IEEE Antennas and Wireless Propagation Letter

Dar clase con bibliotecas en las aulas

Ainda hoje, após várias décadas de conscientização sobre a importância de contar com bibliotecas nas classes e nas escolas, é surpreendente notar que a sempre defendida demanda de alfabetização universal não seja sistematicamente acompanhada por uma constante demanda de instalação de bibliotecas em todas as classes ou, ao menos, em todas as escolas da região. E, mais ainda, quando se conta com o acervo necessário, o que fica faltando são mais programas sistemáticos e constantes que, contra uma lógica de livros únicos e leituras únicas, abram a aula para o universo das inúmeras leituras na diversidade de gêneros que acumulamos através de séculos de cultura escrita.Aún hoy, después de varias décadas de concientización sobre la importancia de contar con bibliotecas en las aulas y en las escuelas, es llamativo advertir que la siempre sostenida demanda de alfabetización universal no sea sistemáticamente acompañada de una constante demanda de instalación de bibliotecas en todas las aulas o, al menos, en todas las escuelas de la región. Más aún, cuando se cuenta con el acervo necesario, hacen falta más programas sistemáticos y sostenidos que, contra una lógica de libros únicos y lecturas únicas, abra la clase al universo de las múltiples lecturas en la diversidad de géneros que hemos acumulado a través de siglos de cultura escrita.Facultad de Humanidades y Ciencias de la Educació

Dar clase con bibliotecas en las aulas

Ainda hoje, após várias décadas de conscientização sobre a importância de contar com bibliotecas nas classes e nas escolas, é surpreendente notar que a sempre defendida demanda de alfabetização universal não seja sistematicamente acompanhada por uma constante demanda de instalação de bibliotecas em todas as classes ou, ao menos, em todas as escolas da região. E, mais ainda, quando se conta com o acervo necessário, o que fica faltando são mais programas sistemáticos e constantes que, contra uma lógica de livros únicos e leituras únicas, abram a aula para o universo das inúmeras leituras na diversidade de gêneros que acumulamos através de séculos de cultura escrita.Aún hoy, después de varias décadas de concientización sobre la importancia de contar con bibliotecas en las aulas y en las escuelas, es llamativo advertir que la siempre sostenida demanda de alfabetización universal no sea sistemáticamente acompañada de una constante demanda de instalación de bibliotecas en todas las aulas o, al menos, en todas las escuelas de la región. Más aún, cuando se cuenta con el acervo necesario, hacen falta más programas sistemáticos y sostenidos que, contra una lógica de libros únicos y lecturas únicas, abra la clase al universo de las múltiples lecturas en la diversidad de géneros que hemos acumulado a través de siglos de cultura escrita.Facultad de Humanidades y Ciencias de la Educació

Dar clase con bibliotecas en las aulas

Ainda hoje, após várias décadas de conscientização sobre a importância de contar com bibliotecas nas classes e nas escolas, é surpreendente notar que a sempre defendida demanda de alfabetização universal não seja sistematicamente acompanhada por uma constante demanda de instalação de bibliotecas em todas as classes ou, ao menos, em todas as escolas da região. E, mais ainda, quando se conta com o acervo necessário, o que fica faltando são mais programas sistemáticos e constantes que, contra uma lógica de livros únicos e leituras únicas, abram a aula para o universo das inúmeras leituras na diversidade de gêneros que acumulamos através de séculos de cultura escrita.Aún hoy, después de varias décadas de concientización sobre la importancia de contar con bibliotecas en las aulas y en las escuelas, es llamativo advertir que la siempre sostenida demanda de alfabetización universal no sea sistemáticamente acompañada de una constante demanda de instalación de bibliotecas en todas las aulas o, al menos, en todas las escuelas de la región. Más aún, cuando se cuenta con el acervo necesario, hacen falta más programas sistemáticos y sostenidos que, contra una lógica de libros únicos y lecturas únicas, abra la clase al universo de las múltiples lecturas en la diversidad de géneros que hemos acumulado a través de siglos de cultura escrita.Facultad de Humanidades y Ciencias de la Educació

Synthesis of 3-alkyl enol mimics inhibitors of type II dehydroquinase: factors influencing their inhibition potency

Several 3-alkylaryl mimics of the enol intermediate in the reaction catalyzed by type II dehydroquinase were synthesized to investigate the effect on the inhibition potency of replacing the oxygen atom in the side chain by a carbon atom. The length and the rigidity of the spacer was also studied. The inhibitory properties of the reported compounds against type II dehydroquinase from Mycobacterium tuberculosis and Helicobacter pylori are also reported. The binding modes of these analogs in the active site of both enzymes were studied by molecular docking using GOLD 5.0 and dynamic simulations studiesFinancial support from the Xunta de Galicia (10PXIB2200122PR and GRC2010/12) and the Spanish Ministry of Science and Innovation (SAF2010-15076) is gratefully acknowledged. BB, AS and AP thank the Spanish Ministry of Science and Innovation for FPU fellowshipsS

Reinforced Concrete Building with IED Detonation: Test and Simulation

There is growing concern about the possibility of a suicide bomber being immolated when the army forces or the law enforcement agencies discover the place where they prepare their material or simply find themselves inside a building. To study the possible effects that these improvised explosive devices (IEDs) would have on the structures, eight tests were carried out with various configurations of IEDs with vest bombs inside a reinforced concrete (including walls and roof) building constructed ad hoc for these tests. These vests were made with different explosives (black powder, ANFO, AN/AL, PG2). For the characterization of these tests, a high-speed camera and pressure and acceleration sensors were used. The structure behaved surprisingly well, as it withstood all the first seven detonations without apparent structural damage. In the last detonation, located on the ground and with a significant explosive charge, the structural integrity of the roof and some of the walls was compromised. The simulation of the building was carried out with the LS-DYNA software with a Lagrangian formulation for the walls, using the LBE (based on CONWEP) module for the application of the charge. Despite the difficulty of this simulation, the results obtained, in terms of applied pressures and measured accelerations, are acceptable with differences of about 20%