Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Humanity and industrialization have led to ecosystems, in all their matrices, being compromised in terms ofpollution generated by different metals. Among them we find mercury and lead, both correspond to metals highlydangerous for all ecosystems and their trophic chains. In this review we will look at the dangers of these metals and theways in which they can be removed, ranging from more traditional processes to adsorption processes withmaterials derived from natural sources and how they can be an effective source of heavy metal removal.  

ABSTRACT: The main intent of the article is to lay out a brief valuation of biological significance of latest macrocyclic complexes of chromium metal with highlighting the synthesis of these complexes and their applications as antimicrobial agents. Antibiotic ministration is the leading perspective of current medical science which is used to resist infections. But nowadays, power of established drugs against microorganisms is persistently decreased due to bacterial resistivity, which creates a serious issue related to public health. Extensive work has been disclosed on macrocyclic complexes of first row transition metals performing as remedy for copious microbial infections and these reports express their equal or higher capacities to resist the infection as compared to other clinically useable drugs. So here in this review, the synthesized complexes of chromium metal, their precursors and their reported biological activities have been discussed.

Most of the whole-field optical methods for vibration measurement have low sensitivity when the points of the studied surface vibrate with the same amplitude. Those techniques also usually require complex and/or expensive solutions which are difficult to implement in engineering processes when the vibration amplitudes are relatively high. In order to overcome those limitations we propose a method for out-of-plane vibration measurement which uses structured light projection. The vibrating surface is obliquely illuminated by straight and parallel interference fringes produced by a Twyman-Green interferometer with a 532-nm laser as light source. In order to enable fringe visualization two techniques were employed, namely, the phase modulation of the fringe pattern by using a vibrating mirror in the interferometer, and a stroboscopic illumination by using a Fabry-Perot etalon amplitude modulator. We demonstrated the technique by measuring the vibration amplitudes of small objects in the millimeter and submillimeter range.

We propose a methodology to narrow down the selection of design parameters of phantoms for calibrating ultrasound devices. For doing so, we model the phantoms as composite materials. Through a mathematical homogenization technique, the global properties of the phantom are given in terms of the volume fractions of its components, their geometric shapes and physical properties. We explore these parameters to determine ranges that yield the desirable values of acoustic impedance and attenuation. The procedure is illustrated for a class of sandwich-like phantoms made of layers of agar of different concentrations with complex elastic moduli. In this example, homogenization provides analytical formulae of the global properties that can be used to identify the layers’ thicknesses and concentrations that yield a low impedance and an average attenuation coefficient. These analytical results are compared with a numerical homogenization method, showing excellent agreement.

El Sistema de Control y Automatización Integrado (IACS) basado en el control de eventos discretos mediante redes de Petri (PN) que abarca el diseño, análisis y validación de modelos de sistemas de bombeo industrial no se utilizan comúnmente. Nuestro caso de estudio es el diseño e implementación de un sistema de supervisión utilizando el software GHENeSys PN y EROS en la Estación de Bombeo "San Juan" en Santiago de Cuba, Cuba. Estas herramientas permiten describir los modelos de los estados del proceso automático local y el funcionamiento del Supervisor, para tener en cuenta, las funciones de Mantenimiento Preventivo y Tratamiento de Alarmas. El IACS parte de la simulación MatLab de los lazos de control principales y utiliza la red jerárquica extendida GHENeSys para modelar un sistema de automatización integrado estructurado modularmente que responde a las demandas funcionales sincronizadas. Esta metodología tiene las ventajas de una modularidad jerárquica completa desde el control local hasta la gestión de producción, varias herramientas modulares de verificación y validación y compatibilidad total con IEC61131. Esto reduce los errores de diseño y el tiempo de implementación con una mayor eficiencia de integración.

This paper presents an improved real time target tracking system based on Cam-Shift and advanced Kalman filter algorithms. The paper, proposes a simple low implementation cost scheme while keeping the high tracking performance. Two degrees of freedom target tracking system based on two hybrid stepper motors with their drive systems is fully designed and implemented to improve the tracking accuracy while keeping low-cost. The potential of the proposed algorithm lies in its ability to accurately detect, track and produce firing commands on the designated target while utilizing low cost on the shelf embedded Microcontroller boards. A low cost Universal Serial Port (USB) camera is used and integrated with the proposed algorithm in order to detect and track maneuvering targets. A series of experiments for stationary and moving objects are carried out for testing the proposed system efficiency. The proposed system enables accurate performance for tracking static and moving objects. Hence it provides a simple and low implementation cost scheme for real time object tracking applications.

In this work, a comparison between the six degrees of freedom (6-DoF) method and the sliding mesh approach in computational fluid dynamics simulations of an Archimedes screw turbine for hydrokinetic applications was performed using ANSYs Fluent software. The numerical curves obtained by representing the power coefficient () values versus the tip speed ratio ( or ) were compared based on the experimental data available in the literature. Therefore, by considering the  values as the comparison benchmark parameter between the numerical and experimental data, the error obtained when using the 6-DoF method and the sliding mesh approach was 13% and 40%, respectively. Both methods allowed the simulation of the rotor rotation, although the 6-DoF method was more accurate in the prediction of the turbine performance, higher computational resources were consumed in comparison with the sliding mesh method, which allows to obtain a computational solution in affordable times.

Heart disease is one of the deadly diseases. Timely detection of the disease can prevent mortality. In this paper, an intelligent system is proposed for the diagnosis of heart disease using clinical parameters at early stages. The system is developed using the Regularized Deep Neural Network model (Reg-DNN). Cleveland heart disease dataset has been used for training the model. Regularization has been achieved by using dropout and L2 regularization. Efficiency of Reg-DNN was evaluated by using hold-out validation method.70% data was used for training the model and 30% data was used for testing the model. Results indicate that Reg-DNN provided better performance than conventional DNN. Regularization has helped to overcome overfitting. Reg-DNN has achieved an accuracy of 94.79%. Results achieved are quite promising as compared to existing systems in the literature.  Authors developed a system containing a graphical user interface. So, the system can be easily used by anyone to diagnose heart disease using the clinical parameters.

Copper Oxide Nanoparticles (CuONPs) show a broad spectrum of antimicrobial activity against various species of microorganisms, including gram-positive and gram-negative fungi and bacteria, but in general gram-negative bacteria are more resistant to the effects of copper nanoparticle ions than gram-positive ones. In this work, synthesis of copper oxide nanoparticles has been carried out using laser ablation methods and the nanoparticles were applied as antibacterial agent against gram-positive bacteria Enterococcus faecalis. Experimentally, Nanoparticle synthesis was carried out using laser ablation with a power of 40 mJ. Antibacterial test with disc diffusion test using disc paper soaked in 0.1% chitosan solution (negative control), sodium hypochlorite (positive control), and copper oxide nanoparticles with a concentration of 60 ppm, 80 ppm, 100 ppm; then put into a petri dish that has been planted with the Enterococcus faecalis bacteria. Copper oxide nanoparticles were formed in chitosan as confirmed by UV-Vis, FTIR, SEM and EDX analysis. Post Hoc Tukey HSD analysis showed a significant difference in the negative control group, and the inhibition zone diameter of the treatment group was the same. The synthesis of nanoparticles using laser ablation fired at a pure copper plate succeeded in producing copper oxide nanoparticles in chitosan solvent. The firing time affects the concentration and size of the nanoparticles. More laser energy is required to produce a smaller particle size due to its antibacterial activity.

Aluminium alloy related to Metal Matrix Composites (AMMC’s) have been achieve enormous comprehensive acknowledgment for aerospace and structural applications, due to its excellent corrosion resistant, good wear resistant, high strength and light weight. In this paper, the experimental study deals with investigation influence of reinforcement (Magnesium oxide and Silicon Carbide) particles on various mechanical properties of aluminium alloy (Al 6061). AMMC was fabricated by stir casting method. The exsitu method was used to fabricate because of its less complexity. The MMC specimens with different weight percentage of reinforcement particles such as 3%, 6% and 9% were prepared. After the fabrication, the ingots were machined for preparation of test samples. The tensile, compression, Impact and hardness test were taken to study the mechanical properties and effect of varying weight percentage of reinforcements. As the outcome, the tensile and compression strength were progressively increase with addition of magnesium oxide and silicon carbide.