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Structural damage detection using inclinometers is getting wide attention from researchers. However, the high price of inclinometers limits this system to unique structures with a relatively high structural health monitoring (SHM) budget. This paper presents a novel low-cost inclinometer, the low-cost adaptable reliable angle-meter (LARA), which combines five gyroscopes and five accelerometers to measure inclination. LARA incorporates Internet of Things (IoT)-based microcontroller technology enabling wireless data streaming and free commercial software for data acquisition. This paper investigates the accuracy, resolution, Allan variance and standard deviation of LARA produced with a different number of combined circuits, including an accelerometer and a gyroscope. To validate the accuracy and resolution of the developed device, its results are compared with those obtained by numerical slope calculations and a commercial inclinometer (HI-INC) in laboratory conditions. The results of a load test experiment on a simple beam model show the high accuracy of LARA (0.003 degrees). The affordability and high accuracy of LARA make it applicable for structural damage detection on bridges using inclinometers.
Asunto(s)
Sistemas Microelectromecánicos , Acelerometría , Sistemas Microelectromecánicos/métodos , Programas InformáticosRESUMEN
Nowadays, low-cost accelerometers are getting more attention from civil engineers to make Structural Health Monitoring (SHM) applications affordable and applicable to a broader range of structures. The present accelerometers based on Arduino or Raspberry Pi technologies in the literature share some of the following drawbacks: (1) high Noise Density (ND), (2) low sampling frequency, (3) not having the Internet's timestamp with microsecond resolution, (4) not being used in experimental eigenfrequency analysis of a flexible and a less-flexible bridge, and (5) synchronization issues. To solve these problems, a new low-cost triaxial accelerometer based on Arduino technology is presented in this work (Low-cost Adaptable Reliable Accelerometer-LARA). Laboratory test results show that LARA has a ND of 51 µg/âHz, and a frequency sampling speed of 333 Hz. In addition, LARA has been applied to the eigenfrequency analysis of a short-span footbridge and its results are compared with those of a high-precision commercial sensor.
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Computing and visualizing sets of elements and their relationships is one of the most common tasks one performs when analyzing and organizing large amounts of data. Common representations of sets such as convex or concave geometries can become cluttered and difficult to parse when these sets overlap in multiple or complex ways, e.g., when multiple elements belong to multiple sets. In this paper, we present a design study of a novel set visual representation, LineSets, consisting of a curve connecting all of the set's elements. Our approach to design the visualization differs from traditional methodology used by the InfoVis community. We first explored the potential of the visualization concept by running a controlled experiment comparing our design sketches to results from the state-of-the-art technique. Our results demonstrated that LineSets are advantageous for certain tasks when compared to concave shapes. We discuss an implementation of LineSets based on simple heuristics and present a study demonstrating that our generated curves do as well as human-drawn ones. Finally, we present two applications of our technique in the context of search tasks on a map and community analysis tasks in social networks.
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Highly photoconductive properties are reported for organic-inorganic hybrid sol-gel thin film materials composed of a classical poly(vinylcarbazole)/2,4,7-trinitro-9-fluorenone (PVK/TNF) polymeric mixture, entrapped in a SiO(2) matrix, whose pores have been chemically modified by organic functional groups. The highest photosensitivity obtained, 3.4 x 10(-10) cm Omega(-1) W(-1) at E 22 V microm(-)1, at the optimum molar ratio between the active components, TNF, PVK, and SiO(2), is in the range of the highest values ever reported for any PVK/TNF-based classical photoconductive material. It is demonstrated that the PVK/TNF-based sol-gel films follow Onsager's classical charge-generation model. The analysis of the photocurrent efficiency (Phi) of PVK/TNF-based sol-gel films by such a model provides the primary quantum yield of thermalized pair formation and the initial thermalized pair distance, phi(0) = 0.12 and r(0) = 66.1 Angstrom, respectively, for the optimized sample. As a result of Onsager's analysis, a notorious improvement of the photocurrent generation process was achieved for low TNF concentrations.
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We report the correction of the shrinkage observed during UV postrecording curing in a holographic solgel material that was recently achieved by the use of various chemical formulations for the composition of the hybrid supporting matrix. We found that a chemical modification of the matrix noticeably attenuates the shrinkage (from 1.3% to 0.4% of the material's initial thickness with the inclusion of just 20% tetramethylorthosilicate), providing a material with improved stability for permanent data storage applications. The holographic properties of samples with different binders are also reported. In addition, a theoretical study has revealed the way by which to compensate for angular deviation in the Bragg condition during UV postrecording by tailoring the binder shrinkage (s), the maximum refractive-index modulation capability of the photosensitive mixture (deltan), or both.
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Se estudio, en la rata, el efecto de la restricción de la ingesta de una dieta balanceada durante la preñez y lactancia, sobre la actividad de gama glutamil transpeptidasa (GGTPO) (E.C.2.3.2.2.) en la glándula mamaria. Los resultados informan que la desnutrición calRorico-proteínica impuesta permanentemente a la rata hembra, disminuye significativamente el crecimiento, contenido de DNA, contenido de proteína y actividad de GGTP en la glándula mamaria, desde el día 16 post-gestación hasta el 5§ día de lactancia, lo que equivale a la duración del experimento. El peso de las crías al nacer y la ganancia de peso al 5§ día de vida postnatal se encontró significativamente disminuida en el grupo desnutrido. Se postula que la disminución de la actividad de GGTP afectó el transporte de algunos aminoácidos y péptidos, en la glándula mamaria, originando una menor disponibilidad intracelular de aminoácidos necesarios para la síntesis de la proteína de la leche y, por lo tanto, una disminución en la secreción láctea
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Embarazo , Ratas , Animales , Femenino , Privación de Alimentos , gamma-Glutamiltransferasa/metabolismo , Glutatión/análisis , Lactancia/metabolismo , Glándulas Mamarias Animales/metabolismo , Peso Corporal , Dieta , Proteínas de la Leche/análisis , Ratas WistarRESUMEN
Se estudian los cambios en la actividad de glutatión S-transferasas (GSHTr) durante el desarrollo de la glándula mamaria y crecimiento de placenta y el efecto de la nutrición materna en estos cambios, durante la preñez y lactancia en ratas. Ratas hembras vírgenes se someten a una restricción dietética alimentándolas desde los 50 días de edad y durante la preñez y lactancia con el 50% (g/100 gramos rata) de la ingesta voluntaria de un grupo control de la misma edad, de una dieta preparada con caseína al 25% suplementada con 0,3% de DL Metionina. A los 16 ó 18 ó 20 días de preñez ó 5- día de lactancia se sacrifican en cada oportunidad 15 ratas de cada grupo control (C) y desnutridas (D) y se les extraen las placentas y las glándulas mamarias inguinales y abdominales. Se estudian en glándulas y órgano la actividad de GSHTr. Los resultados informan que el avance de la preñez disminuyó la actividad de GSHTr en placenta, pero mantuvo con una ligera elevación la actividad en glándulas mamaria. La lactogénesis estimuló dramáticamente la actividad de GSHTr en glándula mamaria; pero la desnutrición crónica materna deprimió la actividad en esta glándula durante la preñez y lactancia. Se discuten los resultados en relación al bajo efecto protector de los tejidos maternos de rata desnutrida contra los efectos tóxicos de substancias que pueden ser transferidos a través de la leche materna
Asunto(s)
Embarazo , Ratas , Animales , Mama/enzimología , Glutatión Transferasa/fisiología , Placenta/enzimología , Nutrición Materna , Estado Nutricional , PreñezRESUMEN
Se estudia la acción del fentanyl y nalbufina sobre las mioclonias inducidas por el etomidato con el objeto de poder establecer su mecanismo, para lo cual se estudiaron 30 pacientes adultos sometidos a legrado uterino instrumental; manejados con fentanyl, nalbufina o solución salina IV previa inducción de la anestesia con etomeidato. En cada paciente se valoró la PAM, FC y FR; dolor venoso, mioclonias y náuseas y vómitos postoperatorios. Ambos morfínicos previenen o atenúan significativamente la frecuencia e intensidad de las mioclonias, por lo que apoyamos un efecto más específico probablemente a nivel del sistema nigroestriado