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En las últimas décadas se ha trabajado activamente para reducir el impacto ambiental generado por las actividades antrópicas que constantemente liberan componentes tóxicos al ambiente generando inestabilidad y daños en la salud de las comunidades biológicas. Entre los diferentes contaminantes, los metales pesados revisten importancia en virtud de sus propiedades, que dificultan su degradación o transformación en otros compuestos menos tóxicos. El cromo es uno de los metales de mayor interés a nivel global por su uso en múltiples industrias. Los métodos convencionales que utilizan materiales cromados en sus procesos, no sólo arrojan cantidades considerables de residuos al ambiente, sino que dan poca cuenta de la fracción de Cr6+ presente en determinados ecosistemas. La biorremediación se ha propuesto como una alternativa económicamente viable y ambientalmente sostenible. El propósito del presente trabajo fue evaluar la capacidad de reducción de cromo por bacterias, aisladas de una matriz de biosólidos de la Planta de tratamiento de aguas residuales (PTAR) San Fernando en la ciudad de Medellín-Colombia. Muestras de biosólidos se cultivaron en Agar Nutritivo enriquecido con diferentes concentraciones de Cr6+. Las cepas que presentaron mayor tolerancia al cromo fueron aisladas para realizar ensayos de reducción por triplicado, monitoreando la concentración del metal en el tiempo. Se obtuvieron siete especies bacterianas diferentes dentro de las cuales se destacaron Staphylococcus saprophyticus, Ochrobactrum anthropi y Bacillus cereus por la capacidad de reducir Cr6+ a 96 h con eficiencias de 29.0%, 61.1% y 100%, respectivamente.

Background Cadmium uptake by cacao plants can affect plant growth, consumer health and commercialisation. To develop mitigation strategies, it is essential to identify the soil characteristics that could influence this absorption. To determine the relationships between cadmium absorption and the soil characteristics of cacao areas, the responses at concentrations of 0, 2, 5, 10 and 20 μg g-1 of cadmium in three soils of these areas and an andisol were evaluated, using 120-day-old seedlings of four cultivars of Theobroma cacao L. Results In the present study, several relationships were found between chemical and physical soil characteristics and available cadmium, such as real and bulk densities, as well as contents of iron, sand, magnesium, potassium, sodium and copper. Additionally, moderate to strong correlations between potassium (r2 = -0.56) and real density (r2 = 0.42), with foliar cadmium, were found. Moreover, a differential deleterious effect on cacao growth in variables such as biomass was corroborated in cadmium concentrations from 5 μg g-1 in soils. There were no statistical differences between cultivars with respect to cadmium uptake or plant growth. Finally, a multiple linear regression model is proposed to estimate the foliar cadmium content (r2 = 0.878). Conclusion Some soil characteristics such as density, as well as sand, clay, aluminium, potassium and iron contents, should be considered before establishing cacao crops to avoid cadmium accumulation. The correlation between potassium with foliar cadmium indicated that potassium could be significant in cadmium uptake mitigation strategies. The high correlation between available cadmium and foliar cadmium indicates that the quantification methodology developed using ethylenediaminetetraacetic acid extractant may be a useful diagnostic tool. © 2021 Society of Chemical Industry.

This article presents a multi-variable control strategy for the regulation of Dissolved Oxygen Concentration in a stirred laboratory-scale bioreactor. The controller manipulates the airflow and agitation speed in the reactor. Departing from a mechanistic model that relates the manipulated variables and the oxygen transfer coefficient, linearized local models of the process are obtained. It is observed that there is high variability in the process behavior with the operating point. Then, a Gain-Scheduled controller is proposed. The strategy varies the agitation speed employing a PI control law and varies the air flow according to a switching law that detects saturations in the manipulated variables. The proposed strategy is evaluated in simulation and implemented in a real bioreactor. Results show that the strategy is able to regulate the oxygen concentration in a wide range of operating conditions.

This study compares detector performance through measurements of Contrast-to-Noise Ratio (CNR) of images obtained by a standard commercial X-ray mammography setup, using a flat panel detector with a 200 μ m thick amorphous Selenium (a-Se) sensor, and a laboratory setup, using a Medipix3RX detector with a 1 mm thick Cadmium Telluride (CdTe) semiconductor sensor. The laboratory setup corresponds to the geometry and X-ray spectrum of the commercial setup. Dose calibrations are applied to ensure comparability of results between both systems. Detection of microcalcifications in breast tissue is crucial for early medical diagnosis of breast cancer development, and improvements in image quality or reduction in radiation dose significantly benefit the field of mammography imaging. The Medipix3RX CdTe detector has the potential to improve mammography imaging due to a combination of two features: a photon-counting detection scheme that allows for electronic noise rejection, integrated in a small pixel pitch of 55 μ m; and the higher X-ray photon absorption efficiency of CdTe, compared to materials such as Silicon (Si) or Se, in the mammography energy range. The comparison between both systems shows better CdTe detector performance when imaging microcalcification structures with sizes between 240 μ m and 540 μ m. The Medipix3RX CdTe detector produces higher CNR values as compared to the a-Se system for the studied speck sizes, at equivalent doses, with up to 30% for 540 μ m structures. For 240 μ m size specks, the Medipix3RX CdTe detector has more than twice better CNR performance than a-Se, even for half the dose values. Our results motivate further research to exploit the potential of the Medipix3RX CdTe detector for clinical mammography implementations, due to the benefit of simultaneous radiation dose reduction and improved imaging performance.

Direct foreign investment is one of the most important economic variables in the world. Aspects related to international investment agreements are reaching an outstanding place in economic international diplomacy. Nowadays, in the multilateral level there is not an agreement regarding investment and therefore this study is focused on this particular type of agreement. In order to reach this objective this study shows, first of all, how different attempts have been developed to get a multicultural a agreement regarding investment, and to refuse the general opinion that says that exponential growth of foreign investment flows in recent years has given impulse to launch a multilateral investment agreement. Secondly, this study discusses about regulations related to foreign investment under current WTO regulations, such as investment, measure agreements, and service agreement. Then, it analyzes what has happened inside the WTO from the creation of the investment team at the Singapore Conference to the failed Conference in Cancun. Finally, it analyzes the main arguments against the multilateral agreement and the effects of future possible multilateral negotiations in investment and it ends with some recommendations and conclusions.

Graphical abstract, Highlights • Near infrared spectroscopy was used for the detection of phenolic content in plant cell cultures. • Multivariate analysis applied to HPLC data was satisfactory to determine changes in the phenolic profile. • Dihydroquercetin increased significantly in T. peruviana cultures treated with SA/MeJA. • Chlorogenate and dihydroquercetin are possible biomarkers of the MeJA effects in T. peruviana., Plant cell suspension culture of T. peruviana is a feasible biotechnological platform for the production of secondary metabolites with anti-proliferative/cytotoxic activity, as phenolic compounds (PC); however, different in in vitro growth conditions may affect the production, demanding strategies to increase the metabolite biosynthesis, as well as the development of sensitive and rapid analytical methods for metabolite monitoring. The Fourier transform near-infrared (FT-NIR) spectroscopy and Reversed-phase high-performance liquid chromatography (RP-HPLC) combined with Multivariate analysis (MVA) were used to detect significant differences in the PC production in cultures treated with two elicitors. The results suggest that the FT-NIR-MVA is useful for discriminating samples according to the treatment, showed significant influence of the PC signal. RP-HPLC-MVA showed that the elicitor effect occurs at 72 h post-elicitation. Detection of dihydroquercetin (maximum concentration = 12.59 mg/L), a flavonoid with anti-cancer properties, is highlighted. Future studies will be aimed at scaling this culture to increase the productivity of dihydroquercetin.

Although Cr(VI)-reducing and/or tolerant microorganisms have been investigated, there is no detailed information on the composition of the microbial community of the biocathode microbial fuel cell for Cr(VI) reduction. In this investigation, the bacterial diversity of a biocathode was analyzed using 454 pyrosequencing of the 16S rRNA gene. It was found that most bacteria belonged to phylum Proteobacteria (78.8%), Firmicutes (7.9%), Actinobacteria (6.6%) and Bacteroidetes (5.5%), commonly present in environments contaminated with Cr(VI). The dominance of the genus Pseudomonas (34.87%), followed by the genera Stenotrophomonas (5.8%), Shinella (4%), Papillibacter (3.96%), Brevundimonas (3.91%), Pseudochrobactrum (3.54%), Ochrobactrum (3.49%), Hydrogenophaga (2.88%), Rhodococcus (2.88%), Fluviicola (2.35%), and Alcaligenes (2.3%), was found. It is emphasized that some genera have not previously been associated with Cr(VI) reduction. This biocathode from waters contaminated with tannery effluents was able to remove Cr(VI) (97.83%) in the cathodic chamber. Additionally, through use of anaerobic sludge in the anodic chamber, the removal of 76.6% of organic matter (glucose) from synthetic waste water was achieved. In this study, an efficient biocathode for the reduction of Cr(VI) with future use in bioremediation, was characterized.

El objetivo del presente artículo es presentar a la comunidad académica, los resultados obtenidos del proyecto de investigación, DIS 968, realizado por el grupo de investigación MEMPED de la Facultad de Estudios a Distancia (FAEDIS) Universidad Militar Nueva Granada, cuyo objetivo fue el de identificar y caracterizar la investigación formativa en los programas de formación de oficiales en Ciencias Militares, Administración Aeronáutica, Administración Naval y Administración Policial de las Fuerzas Militares y de Policía en Colombia. En este sentido, la metodología utilizada por el grupo de investigación, partió desde dos enfoques, el documental y el etnográfico; variables técnicas que se entrelazaron en una triangulación estructural desde lo descriptivo-documental hasta entrevistas sistemáticas que complementan las especificidades y particularidades de los programas objeto de estudio. Dentro de los hallazgos obtenidos, se destaca la descripción de la estructura funcional en la formación de los oficiales “en y para la investigación”, las herramientas didácticas que fortalecen la investigación formativa y, finalmente, los elementos constitutivos que identifican la cultura investigativa propia de cada escuela. Como conclusión, se describen los instrumentos teóricos, pedagógicos y didácticos, que permiten caracterizar, en forma dinámica, la investigación formativa, desde cada una de las escuelas, y se propone la construcción de una segunda fase, de tal modo que describa un modelo de gestión del conocimiento, que reúna el capital intelectual, el capital relacional y el capital del conocimiento, propio para los programas de formación de oficiales de las Fuerzas Militares y de Policía en Colombia.

Graphical abstract, Highlights • Cell suspension cultures from T. peruviana were used to produce secondary metabolites. • Production of phenolic compounds in plant cell cultures was time-dependent. • Elicitation with salicylic acid and MeJA increased biosynthesis of phenolics compounds. • Plant cells exposed to MeJA produced the higher levels of phenolics and antioxidants., The objective was to enhance the production of the phenolic compounds in plant cell suspension cultures of T. peruviana at shake flask scale. The effects of salicylic acid (SA), methyl-jasmonate (MeJA) and the combination of both (SA/MeJA) were studied. Elicitor concentration, elicitation time and harvest time of cells were optimized. Phenolic compound content (PCC), flavonoid content (FC) and antioxidant activity (AA) were determined by the folin-ciocalteu method, flavonoid-aluminum complexation method and the ABTS assay, respectively. Differences between intracellular metabolite profiles due to the mentioned treatments were analyzed by Thin-layer chromatography and High-performance liquid chromatography. Highest PCC, FC and AA were obtained under the following treatments: 3 μM MeJA > 3 μM MeJA/300 μM SA > 300 μM SA > control, when elicited on the 4th day and harvested 96-h post-elicitation. It was demonstrated that exposure to 3 μM MeJA increase 1.49-fold of PCC, 1.66-fold of AA and 2.55-fold of FC compared to the control culture.

En este trabajo se presenta el desarrollo de un modelo dinámico del clima en un invernadero ubicado en la Sabana de Bogotá. Se realiza la estimación de un modelo tipo caja negra obtenido a partir de datos experimentales. Se propone una estructura a partir de principios físicos que divide el sistema en dos volúmenes de control dados por el aire libre dentro del invernadero y el aire atrapado por el follaje. El modelo es seleccionado, dentro de una familia de sistemas línea- les descritos en variables de estado, a través de métodos de identificación por subespacios. El modelo obtenido es capaz de explicar el comportamiento del clima en el aire y en el follaje con errores inferiores al 8%. Este desempeño es comparable al de otros estudios reportados en la literatura, con la ventaja de que el modelo empleado es lineal.

Microboiling is commonly used in thermal inkjet atomizers (TIJ) and microelectromechanical (MEM) devices. The TIJ and MEM devices performance is closely related to the dynamics of the bubble used to operate them; therefore, it is important to determine the conditions of input energy and power leading to specific bubble dynamics. The objective in this work is the characterization, in a confined space, of the bubble dynamics on a range of input conditions of energy and power and what is the effect of the input conditions on the bubble extractable mechanical efficiency. Mechanical efficiency is defined by the ratio of the integral of the mechanical work (work done by the bubble expansion due to the elevated internal pressure relative to atmospheric pressure minus the increase in bubble surface energy) to the total energy input to the microheater. Bubbles are generated with energies of 7–17 μJ under high heating rates and short pulses in deionized water. Resulting nucleation temperature measurements are consistent with homogeneous nucleation. The bubble lifecycle shows strong dependence on the input heater energy and input heating rate. This work presents new results in bubble growth where growth–shrink–growth derived from specific energy conditions. The bubble growth–shrink–growth may be due to subcooled fluid, local variation in the pressure field, and by the surface tension driven change in curvature of the bubble. Mechanical bubble efficiencies result in small values suggesting most of the energy applied to the heater is distributed in other processes which may include increasing the internal energy of the heater film and the fluid.

This paper focuses on the measurement of spectroscopic signatures of Chemical Warfare Agent Simulants (CWAS), degradation products of chemical agents and Toxic Industrial Compounds (TIC) using vibrational spectroscopy. Raman Microscopy, Fourier Transform Infrared Spectroscopy in liquid and gas phase and Fiber Optics Coupled-Grazing Angle Probe-FTIR were used to characterize the spectroscopic information of target threat agents. Ab initio chemical calculations of energy minimization and FTIR spectra of Chemical Warfare Agents were accompanied by Cluster Analysis to correlate spectral information of real agents and simulants.

La selección de métodos apropiados para muestreo y análisis es un aspecto importante en el estudio de plagas subterráneas. El conocimiento de su biología, depende del uso de herramientas sensibles para su detección en el ambientecomplejo del suelo y las raíces. Recientemente se ha propuesto el uso de espec-troscopia infrarroja cercana (conocida como NIR, por su sigla en inglés) para el diagnóstico fitosanitario no destructivo en cultivos, aprovechando la manifestación de propiedades ópticas únicas para cada grupo de plantas y organismos. El objetivo de este trabajo fue evaluar el uso de espectroscopía NIR en muestras de hojas y suelo rizosférico, para detectar la presencia del insecto subterráneo Eurhizococcus colombianus en cultivos de mora (Rubus glaucus Benth.), en la región del Oriente antioqueño. La información obteni-da en siete fincas distribuidas en cinco municipios indica que a través de los patrones espectrales de las hojas y el suelo rizosférico es posible clasificar las plantas con presencia o ausencia del insecto dentro de cada finca. Sin embargo, no fue posible establecer un modelo general para todas las fincas. Los resultados obtenidos permiten vislumbrar una herramienta no destructiva muy promisoria para detectar el insecto y entender las condiciones asociadas con su presencia en el cultivo, lo que favorecería el diseño de estrate-gias de manejo de este tipo de plaga, con base en el conocimiento de su ecología, ayudando así a la toma de decisiones ambientalmente amigables, razonables y oportunas por parte de los agricultores.

La inversión extranjera directa es una de las variables económicas más importantes en el contexto mundial, lo que hace que las cuestiones concernientes a los acuerdos internacionales de inversión estén pasando a ocupar un lugar destacado en la diplomacia económica internacional. Pero hoy en día en el plano multilateral no existe ningún acuerdo de carácter general sobre las inversiones y este último tipo de acuerdo de inversiones es en el que se centra el presente trabajo. Para lograr este objetivo, en primera instancia se contará cómo se han desarrollado los diferentes intentos de lograr un acuerdo multilateral en el tema de inversión y desmentir de algún modo la opinión dominante de que el crecimiento exponencial de los flujos de inversión extranjera en años recientes ha dado ímpetu para lanzar un acuerdo multilateral de inversión. Luego, se comentará acerca de las provisiones relacionadas al tema de inversión extranjera bajo el actual régimen de la Organización Mundial de Comercio (OMC), como es el acuerdo sobre las medidas de inversiones y el acuerdo sobre servicios. Enseguida, se analizará lo que ha sucedido al interior de la OMC desde la creación del grupo de trabajo de inversión en la conferencia de Singapur, hasta la fracasada conferencia de Cancún. Para después analizar los principales argumentos que hay en contra de un acuerdo multilateral y los efectos de unas futuras posibles negociaciones multilaterales en inversión para terminar con algunas recomendaciones y conclusiones.

A numerical analysis of the evaporation process of small water droplets with diameters of 1 mm or less that are gently deposited on a hot isothermal solid surface has been performed. This study considers the internal fluid motion that occurs as a result of the thermocapillary convection in the droplet and it determines the effect of fluid motion on the heat transfer between the drop and the solid surface. This study is particularly relevant because the internal fluid motion has not been considered in previous numerical and analytical models presented in the literature. To assess the effects of internal fluid motion, the model results are compared to numerical results provided by a heat conduction model that neglects the fluid motion. The Navier-Stokes and Thermal Energy equations are solved using the Artificial Compressibility Method with Dual Time Stepping. Boundary-fitted grids are used to track the changes in the droplet surface shape during the evaporation process. The numerical simulations have demonstrated that the internal fluid motion provides vastly different temperature distributions in the drop compared to the results from the heat conduction model that neglects fluid motion. The evolution of the droplet geometry was simulated from an initial spherical-shaped cap until the contact angle was close to the receding contact angle.

12 p., N-acyl homoserine lactones are key components of quorum sensing, the bacterial communication system. This communication mechanism regulates the expression of genes, including those involved in virulence and biofilm formation. This system can be interrupted by the action of enzymes that hydrolyze the signaling molecules. In this work, we studied the enzymatic properties of a recombinant AHL-lactonase from Bacillus thuringiensis strain 147-11516, using substrates with acyl chains of different length (C4-HSL, C6-HSL, C7-HSL, C8-HSL and C10-HSL), we also investigated the effect of pH (5.0–9.0), temperature (20–70 °C), concentration of monovalent, divalent and trivalent metals ions (0.2 and 2.0 mM) and EDTA. The results showed that the recombinant AHL-lactonase had biological activity in alkaline pH conditions (8.0) and high temperature (47 % of hydrolyzed substrate at 60 °C). The recombinant AHL-lactonase has activity on substrates with different acyl chain length. However, the activity of the recombinant enzyme was decreased in the two concentrations of all metal ions evaluated but was not inhibited by EDTA. The affinity of the enzyme for all substrates tested and its performance, in the evaluated conditions, suggest that the AHL-lactonase from B. thuringiensis strain 147-11516 could be used as a strategy for disruption of the Gram-negative bacteria communication system under normal and challenging conditions.

A new conservative iterative-based zonal decomposition technique for the solution of complex heat conduction problems is proposed. This numerical technique is based on dividing the domain into subdomains and ensuring that the heat flux and temperature are continuous at the boundary between subdomains. An example problem is used to illustrate the zonal decomposition technique for both steady and transient problems. This numerical technique results in accuracy which equals or exceeds traditional finite difference solutions and solution times which are significantly less than traditional finite difference solutions. A numerical relaxation parameter is introduced and its value is optimized to provide the most rapid convergence to an accurate solution.

Abstract This paper summarizes work conducted in design and development of commercial and demonstration-scale Ocean Thermal Energy Conversion (OTEC) powerplants, and discusses conditions required for commercial implementation, expanding on the information provided by the same authors in the 2009 OTC conference. It documents that commercial OTEC plants for power and potable water generation, developed from commercially available equipment and techniques, are technically feasible today. If favorable financial and market conditions are present, such plants are also economically viable. Key factors for economic viability are long-term financing and stable and favorable interest rates, both of which in turn require a long term commitment for use of the power generated by the plant. Introduction Ocean thermal energy conversion (OTEC) is a renewable energy technology that is applicable to most parts of the world's deep oceans in tropical and sub-tropical areas, where the temperature difference between warm surface and the cold deep water is equal or greater than 20 °C (63 °F). In essence, the technology works by recovering the solar energy absorbed by the ocean. Since the temperature differential suffers very little fluctuation, OTEC is able to generate power on a continuous (baseload) basis, as opposed to some renewable technologies, such as solar and wind. OTEC is most attractive for tropical locations where deep water is available at short distance from shore (less than 6 miles or 10 km), and the marine environment is sufficiently stable to allow operation. [1]. A feature that is particularly attractive is that, if desired, OTEC can be used to co-produce potable water through desalination, in addition to electric power. It is estimated that up to 2 million liters per day (0.5 million gallons per day) can be produced for each megawatt of electricity generated [2] OTEC requires no fuel. Thus, cost of producing electricity and water is not susceptible to the volatility that affects other energy sources such as petroleum, coal and natural gas. Energy can be generated from purely local sources at a cost that is essentially fixed and predictable. Further, since no fuels or radioactive materials are used, environmental impacts (including greenhouse gas generation) are much less than those of conventional methods of power generation. Basic Principles The basic principles of OTEC have been presented in multiple publications (such as [1], [2] and [3] among others). All OTEC plants are heat engines that convert heat into work through the energy gradient between a " source?? and a " sink.?? The basic principle is the same of a steam engine, although in the case of OTEC, the temperature gradient is much smaller. This makes OTEC plants much larger than steam plants of comparable generating capacities.

The increasing power density on electronic components has resulted in temperature problems related to the generation of hot spots and the need to remove high heat flux in small areas. This work is aimed at the cooling of small surfaces (1 mm × 1.2 mm) by using a monodisperse spray from thermal ink jet (TIJ) atomizers. Heat fluxes near the critical heat flux (CHF) are obtained for different conditions of cooling mass flow rate, droplet deposition, and number of active droplet jets. Experimental results at quasiequilibrium show the heat flux scales to the cooling mass flow rate. It is observed that two simultaneously activated jets result in slightly smaller heat flux compared to a single jet of droplets for the same mass flow rate. Droplet momentum and spreading or splashing, as determined by a combination of Weber number and Reynolds number effect via K = We1/2 Re1/4 , may impact the efficiency of the delivery of the cooling mass flow. Current experimental results at K = 24.5 and K = 52.2 for the copper surface temperatures ranging 110 – 120 °C indicate there is little influence of the splashing on the heat dissipation. System heat losses are measured experimentally and compared to a numerical and analytical solution to estimate the actual heat dissipated by the droplet change of phase.Copyright © 2009 by ASME

Idiopathic frozen shoulder is a common medical diagnosis for patients seeking physical therapy. Radiographic and surgical evidence exists that describes the coracohumeral ligament (CHL) as a major contributor to lack of external rotation in patients diagnosed with frozen shoulder. No stretching techniques targeting the anatomical fiber orientation of the CHL have been reported in the literature. This single-patient case-report describes the use of a positional stretching technique of the CHL on a 51-year-old female diagnosed with phase I frozen shoulder. The patient completed 8 in-office visits and 17 home exercise program sessions of positional CHL stretching combined with a simple volitional rotator cuff exercise program in a 4-week period. The patient's Disabilities of the Arm Shoulder and hand (DASH) scores improved from 65 to 36 and Shoulder Pain and Disability Index (SPADI) scores improved from 72 to 8 and passive external rotation from 20 degrees to 71 degrees . While a cause-and-effect relationship cannot be inferred from a single case, this report may foster further investigation regarding the role of the CHL in patients with stage-I and stage-II frozen shoulder as well as therapeutic strategies to help reduce loss of mobility and function.

The use of liquid explosives by terrorists has raised the attention to the use of hazardous liquids as threats to people, buildings and transportation systems. Hazardous liquids such as explosive mixtures, flammables or even chemical warfare agents (CWA) can be concealed in common containers and pass security checks undetected. This work presents three non invasive, non destructive detection approaches that can be used to characterize the content of common liquid containers and detect if the liquid is the intended or a concealed hazardous liquid. Fiber optic coupled Raman spectroscopy and Stand off Raman spectroscopy were used to inspect the content of glass and plastic bottles and thermal conductivity was used to asses the liquid inside aluminum cans. Raman spectroscopy experiments were performed at 532 nm, 488 nm and 785 nm excitation wavelengths. The hazardous liquids under consideration included CWA simulant DMMP, hydrogen peroxide, acetone, cyclohexane, ethanol and nitric acid. These techniques have potential use as a detector for hazardous liquids at a check point or to inspect suspicious bottles from a distance.

Fiber optics coupled-grazing angle probe Fourier transform infrared (FTIR) spectroscopy and infrared microspectroscopy have been used for characterization of the distribution and form of layers of some explosives deposited on stainless steel sheets. Among the explosives tested were trinitrobenzene, HMX and Tetryl. Various solvents were used to deposit the films on stainless steel slides. Isopropyl alcohol was the preferred solvent because it produced more homogeneous mass distributions of target explosives on the substrates. The film thickness, analyte distribution and the relation of thickness to infrared absorption/reflection response of these explosives were compared with those previously reported for TNT, 2,4-DNT and RDX. This comparison was used for described the general optical behavior of the explosives studied.

This work was focused in the measurement of spectroscopic signatures of Chemical Warfare Agent Simulants (CWAS) and degradation products of chemical agents using vibrational spectroscopy for the generation of spectroscopic libraries. The chemicals studied were: DMMP, DIMP, 2-CEES, 2-BAET, 1,4-thioxane, thiodiglycol sulfoxide, dihexylamine, cyclohexylamine, among others. Raman microscopy experiments were performed at different excitation wavelengths that spanned from NIR at 1064 and 785 nm to the VIS at 532, 514.5 and 488 nm and even the deep ultraviolet region at 244 nm. For the compounds studied the optimum excitation lines were 488 nm and 532 nm with a laser power of 25 mW. Among the most prominent bands were at these incident wavelengths were located ca. 652 and 1444 cm-1. Fourier Transform Infrared Spectroscopy in liquid and gas phase and Fiber Optics Coupled-Grazing Angle Probe-FTIR (FOCGAP- FTIR) were used to characterize the spectroscopic signature of target threat agents. The surface experiments were performed at detection levels of about 1 mg/cm2 suggest that limits of detection (LOD) achievable could be as low as nanograms/cm2. Remote sensing experiments were performed using a telescope coupled with a Raman spectrophotometer as a function of power and acquisition time. Characterization of compounds by vibrational spectroscopy and the early stages of the transition from the lab based experiments to remote detection experiments will be presented.

Numerical simulations of the thermal inkjet (TIJ) droplet ejection process are performed. The computational approach is based on a volume of fluid (VOF) formulation. This method allows determining the coupled flow and thermal fields in the firing chamber in addition to the phase change processes that take place during the drive bubble formation, expansion, and collapse. The drive bubble pressure is a result of the phase change heat transfer during the heating pulse and is not imposed by a pressure heuristic approach. A commercially available TIJ architecture was chosen as a baseline to assess the computational model predictions of ejected droplet volume and droplet velocity during a firing cycle. These computational model predictions were compared to experimental results demonstrating an excellent agreement. The transient histories of pressure in the vapor bubble, temperature, and heat transfer rate to the fluid are analyzed to explain some of the relevant physical processes observed.Copyright © 2007 by ASME

An actively operated standoff infrared detection system was designed from commercial infrared equipment: VECTOR 22 FTIR (Bruker Optics), an external mirror and an external MCT detector. One type of experiment was done for IR detection of high explosives RDX and TNT on reflective surfaces. In the detection on surface, the samples were move to different distances and a beam of infrared light was reflect on surface in angle of ~ 0° (backward collection from surface normal). First the samples: 2 to 30 μg/cm2 of high explosives TNT and RDX were characterized after depositing on stainless steel reflective surfaces using Reflection-Absorption Infrared Spectroscopy (RAIS). Then targets were moved to increasing distances: 3 to 12 feet and remote-sensed spectra were collected in active reflectance mode. The limits of detection were determined for all distances measured in both nitroexplosives. Limit of detection of 18 and 20 μg/cm2 for TNT and RDX respectively in the longest distances measured.

Fiber Optic Coupled/Grazing Angle Probe Fourier Transform Infrared Spectroscopy has made possible to develop new methods for detection of traces of chemical compounds on surfaces. Thermal Inkjet Technology is able to deposit very small amounts of chemical compounds, including energetic materials, in a specific location on a surface. Aliquots of TNT solutions were deposited on stainless steel film. A thin coating of TNT can be produced by controlling the concentration of TNT, the number of drops dispensed and the distribution of drops over the surface. A Vector 22, a Bruker Optics FTIR fiber coupled to a Remspec Corp. grazing angle head was used for the experiments. The spectra were recorded at 4 cm -1 resolution and 50 scans. The results of the experiments gave intense absorption bands in the fingerprint region of the infrared spectra that were used for quantification. Chemometrics routines were applied in the enhancement of the quantitative analysis.

The objective of this research is to design and develop a multi-sensor capable of fast detection and of recognition optimization of the techniques for used for quantification of TATP by Pattern Recognition. In particular, the long range goal of the research is to use sensor fusion and sensor “talking” modalities to couple Stand Off detectors with Chemical Point detectors for detection of airborne chemical agents and detection of Improvised Explosive Devices (IEDs). Vibrational spectroscopy techniques are very fast and can be used for real time detection. Good results have been obtained with various target molecular (chemical) systems such as TATP, TNT and DNT. Samples of TATP were detected and quantified in air, in solution and in solid phase on surfaces by different techniques. FTIR Spectroscopy and GS-MS were used to generate new analytical procedures for detection and analysis of the organic peroxide. These procedures were compared and taken to their limits by optimization with Chemometrics, Partial Least Squares (PLS), and Discriminant Analysis (DA).

In this paper we shall consider the existing normative framework of the law of armed conflict, the jus in bello, as it relates to protection of the environment. We will review customary law of aimed conflict and highlight major conventional developments to assess the necessity and feasibility for reform in light of the trend in international environmental law to impose explicit environmental protection obligations on states. The Persian Gulf War of 1991, illustrates the issues presented and the conflicting values inherent in these two branches of international law. The post-war debate raised the questions whether the environment" is adequately protected by existing law from the environmentally destructive potential of modern warfare, or is new conventional law on wartime environmental protection needed.12 Serious consideration of these questions brings the international law-making process to a crossroads as it attempts to accommodate evolving environmental law norms, such as a yet to be defined "right of the environment", with countervailing values encompassed in the laws of armed conflict, which emphasize military necessity despite detriment to the environment.

El presente artículo caracteriza la importancia de la investigación en la educación basada en prácticas reflexivas, así como los proyectos de aula como sistema de investigación y de construcción de conocimientos; fundamenta su posición teórica desde cuatro puntos de vista: el punto de vista pedagógico y epistemológico, el hermenéutico, desde las TIC, y finalmente, desde el pensamiento crítico, para luego, a nivel praxiológico, caracterizar la articulación de la investigación formativa y los proyectos pedagógicos de aula, en las escuelas de formación de oficiales de las FFMM y de Policía en Colombia.

Coastal developments in Venezuela are leading to the rapid destruction of the mangrove forests. Population pressure leads to an overcrowding of public recreational beaches and the wealthy are increasingly seeking out previously deserted coasts. A rash of summer houses built on stilts over the shallow water is now extending around the mangrove areas, causing pollution, erosion and a progressive deterioration of the coastal environment.