Chemical classification of explosives

This work comprehensively reviews some fundamental concepts about explosives and their two commonly used classifications based on either their velocity of detonation or their application. These classifications are highly useful in the military/legal field, but completely useless for the chemical determination of explosives. Because of this reason, a classification of explosives based on their chemical composition is comprehensively revised, discussed and updated. This classification seeks to merge those dispersed chemical classifications of explosives found in literature into a unique general classification, which might be useful for every researcher dealing with the analytical chemical identification of explosives. In the knowledge of the chemical composition of explosives, the most adequate analytical techniques to determine them are finally discussed

The discrimination of 72 nitrate, chlorate and perchlorate salts using IR and Raman spectroscopy

Inorganic oxidizing energetic salts including nitrates, chloratesand perchlorates are widely used in the manufacture of not only licit pyrotechnic compositions, but also illicit homemade explosive mixtures. Their identification in forensic laboratories is usually accomplished by either capillary electrophoresis or ion chromatography, with the disadvantage of dissociating the salt into its ions. On the contrary, vibrational spectroscopy, including IR and Raman, enables the non-invasive identification of the salt, i.e. avoiding its dissociation. This study focuses on the discrimination of all nitrate, chlorate and perchlorate salts that are commercially available, using both Raman and IR spectroscopy, with the aim of testing whether every salt can be unequivocally identified. Besides the visual spectra comparison by assigning every band with the corresponding molecular vibrational mode, a statistical analysis based on Pearson correlation was performed to ensure an objective identification, either using Raman, IR or both. Positively, 25 salts (out of 72) were unequivocally identified using Raman, 30 salts when using IR and 44 when combining both techniques. Negatively, some salts were undistinguishable even using both techniques demonstrating there are some salts that provide very similar Raman and IR spectra

Analysis of different materials subjected to open-air explosions in search of explosive traces by Raman microscopy

Post-explosion scenes offer such chaos and destruction that evidence recovery and detection of post-blast residues from the explosive in the surrounding materials is highly challenging and difficult. The suitability of materials to retain explosives residues and their subsequent analysis has been scarcely investigated. Particularly, the use of explosive mixtures containing inorganic oxidizing salts to make improvised explosive devices (IEDs) is a current security concern due to their wide availability and lax control. In this work, a wide variety of materials such as glass, steel, plywood, plastic bag, brick, cardboard or cotton subjected to open-air explosions were examined using confocal Raman microscopy, aiming to detect the inorganic oxidizing salts contained in explosives as black powder, chloratite, dynamite, ammonium nitrate fuel oil and ammonal. Post-blast residues were detected through microscopic examination of materials surfaces. In general, the more homogeneous and smoother the surface was, the less difficulties and better results in terms of identification were obtained. However, those highly irregular surfaces were the most unsuitable collectors for the posterior identification of explosive traces by Raman microscopy. The findings, difficulties and some recommendations related to the identification of post-blast particles in the different materials studied are thoroughly discussed

Detection and identification of explosives by surface enhanced Raman scattering

Surface Enhanced Raman Scattering (SERS) has undergone an important development over the last few years, particularly in the detection and identification of extremely low traces of explosives. The large number of studies and results generated by this increasing research makes a comprehensive overview necessary. This work reviews in detail that research focused on the identification of explosives by SERS, including TNT, DNT, RDX, PETN, TATP, HMTD, perchlorate, etc. either in bulk state, in solution or in vapour phase. In brief, TNT and DNT have been widely studied by SERS due to its aromatic structure and LODs down to 5&#-10 zg and 10-17&-10-13 M have been achieved. The other explosives have been quite less researched; therefore, few results are available to be compared and a bit more modest LODs have been reached such as 10-13 M for RDX, 10‑4 M for TATP, 5 pg for PETN, or 10-9 M for perchlorate. In addition, the challenges of detecting both explosives vapours and perchlorate anion by SERS are thoroughly discussed.Prevention of and Fight against Crime Programme European Commission - Directorate-General Home Affair

La evaluación de centros y planes de mejora en Extremadura: el papel de la Inspección de Educación

The aim of this paper is to list the different actions contained in the action plans of the Education Inspectorate in Extremadura related to the evaluation of schools. For this purpose, this paper reviews the activities of different administrative units related to school evaluation, in accordance with the functions attributed by the autonomous educational regulations of Extremadura. It also refers to the so-called "Plan for the improvement of educational success" established in 2011 by the Education Act of Extremadura, assessing its limited practical development. Finally, and in the absence of being able to present a plan for the evaluation of schools established by the educational administration in Extremadura, a review is made of the different common and priority actions with a more or less direct relationship with the evaluation of schools contained in the current institutional plans of the education inspectorate in Extremadura: The Master Plan 2023-2026 and the Annual General Plan 2023/24. An unavoidable mention is included of an Erasmus+ project, directly related to school evaluation and improvement plans, in which the education inspectorate of Extremadura has participated. The work ends with the contributions of the education inspectorate to the internal evaluation of schools in Extremadura.El objetivo de este trabajo es enumerar las diferentes actuaciones contenidas en los planes de actuación de la Inspección de Educación en Extremadura relacionadas con la evaluación de centros. Para ello, el presente trabajo hace un recorrido por actividades de diferentes unidades administrativas relacionadas con la evaluación de centros, de acuerdo con las funciones atribuidas por la normativa autonómica educativa extremeña. Así mismo, se alude al denominado “Plan de mejora de éxito educativo” establecido en el año 2011 por la Ley de Educación de Extremadura, valorando el limitado desarrollo práctico del mismo. Por último, y a falta de poder presentar un plan de evaluación de centros establecido por parte de la administración educativa en Extremadura, se hace un recorrido por las diferentes actuaciones, habituales y prioritarias, con relación más o menos directa con la evaluación de los centros educativos contenidas en los vigentes planes institucionales de la inspección de educación en Extremadura: el Plan Director 2023-2026 y el Plan General Anual 2023/24. Se incluye una ineludible mención a un proyecto Erasmus+, directamente relacionado con evaluación de centros y planes de mejora, en el que ha participado la inspección de educación de Extremadura. Finaliza el trabajo con las aportaciones de la inspección de educación a la evaluación interna de centros en Extremadura

Interpreting the near infrared region of explosives

The NIR spectra from 1000 to 2500 nm of 18 different explosives, propellant powders and energetic salts were collected and interpreted. NIR spectroscopy is known to provide information about the combination bands and overtones of highly anharmonic vibrations as those occurring in XH bonds (CH, NH and OH). Particularly intense and complex were the bands corresponding to the first combination region (2500&#-1900&;8239#nm) and first overtone stretching mode (2nu) of CH and NH bonds (1750&#-1450&;8239#nm). Inorganic oxidizing salts including sodium/potassium nitrate, sodium/potassium chlorate, and sodium/potassium perchlorate displayed low intense or no NIR bands

Valoración del riesgo de tromboembolismo venoso en pacientes hospitalizados con patología médica: correlación y concordancia entre los puntajes de riesgo Wells, Ginebra y PRETEMED, Hospital Nacional Arzobispo Loayza, 2008

Expone el riesgo de enfermedad tromboembólica venosa (ETEV) entre los pacientes con patología médica hospitalizados en los servicios de medicina interna del Hospital Nacional Arzobispo Loayza (HNAL) mediante los puntajes Wells, Ginebra y PRETEMED y evaluar el grado de correlación y concordancia entre los mismos. Se utilizó un diseño observacional, descriptivo, trasversal, retrospectivo, en el cual se valoró el riesgo de ETEV, tanto de trombosis venosa profunda (TVP) como de tromboembolia pulmonar (TEP), según los puntajes PRETEMED, Wells y Ginebra. Todos los casos consecutivos de pacientes con diagnóstico médico no quirúrgico hospitalizados durante el mes de abril en el HNAL que accedieron a dar su consentimiento informado para participar en el estudio, fueron evaluados. Luego de los cual se cuantificó el grado de correlación y concordancia entre las escalas. Durante el periodo de estudio ingresaron al HNAL un total de 205 pacientes médicos no quirúrgicos (66.67% en mujeres y un 33.33% en varones, con una edad promedio de 56.0 ± 21.1 años de edad). De acuerdo con las escalas Wells TVP (0.38 ± 0.66 pts), Wells TEP (0.42 ± 0.94 pts), Ginebra TEP (1.61 ± 1.85 pts) y PRETEMED ETEV (1.83 ± 1.91 pts) el 94.2%/ 5.8%/ 0.0%, el 94.6%/ 4.9%/ 0.5%, el 92.2%/ 7.3%/ 0.5% y el 80.9%/ 8.3%/ 10.7% calificaban como de bajo, intermedio y alto riesgo respectivamente. Considerando sólo los puntajes acumulados se encontró una correlación cuando menos significativa entre todas las escalas (r: 0.2157 – 0.6074, p<0.01). Considerando sólo categorías de riesgo bajo, intermedio y alto, la correlación sólo fue significativa entre PRETEMED con el resto de escalas y entre ambas escalas Wells (rho: 0.1811 – 0.3529, p<0.01). Considerando categorías de riesgo bajo versus no bajo, la correlación sólo fue significativa entre PRETEMED con el resto de escalas y entre ambas escalas Wells (tau-b: 0.1833 – 0.3556, p<0.01). Cabe precisar que PRETEMED y Wells TVP (r =0.6074; rho =0.3529; tau-b =0.3556; para todos p<0.01), fueron la única pareja de escalas que alcanzó una correlación cuando menos escasa. Respecto a la concordancia, PRETEMED demostró mantener cuando menos algún grado de concordancia significativo con todas las escalas (kappa: 0.0461 – 0.2037; para todos p<0.05), sin embargo, este sólo alcanzó el rango de concordancia baja con las escalas Wells TVP (kappa =0.2037; p<0.01). Los resultados de nuestro estudio indican que si bien PRETEMED demostró sostener algún grado de correlación y concordancia con las escalasTrabajo académic

Simple multispectral imaging approach for determining the transfer of explosive residues in consecutive fingerprints

This novel investigation focused on studying the transfer of explosive residues (TNT, HMTD, PETN, ANFO, dynamite, black powder, NH4NO3, KNO3, NaClO3) in ten consecutive fingerprints to two different surfaces &- cotton fabric and polycarbonate plastic &- by using multispectral imaging (MSI). Imaging was performed employing a reflex camera in a purpose-built photo studio. Images were processed in MATLAB to select the most discriminating frame &- the one that provided the sharpest contrast between the explosive and the material in the red-green-blue (RGB) visible region. The amount of explosive residues transferred in each fingerprint was determined as the number of pixels containing explosive particles. First, the pattern of PETN transfer by ten different persons in successive fingerprints was studied. No significant differences in the pattern of transfer of PETN between subjects were observed, which was also confirmed by multivariate analysis of variance (MANOVA). Then, the transfer of traces of the nine above explosives in ten consecutive fingerprints to cotton fabric and polycarbonate plastic was investigated. The obtained results demonstrated that the amount of explosive residues deposited on successive fingerprints tended to undergo a power or exponential decrease, with the exception of inorganic salts (NH4NO3, KNO3, NaClO3) and ANFO (consists of 90% NH4NO3)

Determination of nanogram microparticles from explosives after real open-air explosions by confocal Raman microscopy

Explosives are increasingly being used for terrorist attacks to cause devastating explosions. The detection of their post-blast residues after an explosion is a high challenge, which has been barely investigated, particularly using spectroscopic techniques. In this research, a novel methodology using confocal Raman microscopy has been developed for the analysis of post-blast residues from ten open-air explosions caused by ten different explosives (TNT, RDX, PETN, TATP, HMTD, dynamite, black powder, ANFO, chloratite, and ammonal) commonly used in improvised explosive devices. The methodology for the determination of post-blast particles from explosives consisted of examining the samples surfaces with both the naked eye, first, and microscopically (10x and 50x), immediately afterward; and finally, analysing the selected residues by confocal Raman spectroscopy in order to identify the post-blast particles from explosives. Interestingly, confocal Raman microscopy has demonstrated to be highly suitable to rapidly, selectively and non-invasively analyse post-blast microscopic particles from explosives up to the nanogram range

Study of the adhesion of explosive residues to the finger and transfer to clothing and luggage

It is important to understand the extent of transfer of explosive particles to different surfaces in order to better evaluate potential cross-contamination by explosives in crowded security controls such as those at airports. This work investigated the transfer of nine explosive residues (ANFO, dynamite, black powder, TNT, HMTD, PETN, NH4NO3, KNO3, NaClO3) through fingerprints from one surface to another. First, the extent of adhesion of explosive residues from different surfaces to the bare finger, nitrile and latex gloves was studied. Then, the transfer of explosive residues from one surface to another through fingerprints was investigated. Cotton fabric (hereinafter referred to as cotton) as clothing material and polycarbonate plastic (hereinafter referred to as polycarbonate) as luggage material were chosen for the experiments. These surfaces containing explosive particles were imaged using a reflex camera before and after the particles were transferred. Afterwards the images were processed in MATLAB where pixels corresponding to explosive residues were quantified. Results demonstrated that transfer of explosive residues frequently occurred with certain differences among materials. Generally, the amount of explosive particles adhered to the finger decreased in the following order: skin>latex>nitrile, while the transfer of particles from the finger to another surface was the opposite. The adhesion of explosive residues from polycarbonate to the finger was found to be better compared to cotton, while the amount of particles transferred to cotton was higher