AN EXPERIMENTAL AND NUMERICAL STUDY OF NANOMECHANICAL BEHAVIOR OF HARD/SOFT MULTILAYERED COATINGS

Multilayer thin film composites, sometimes referred to as nanolaminates, have emerged as an important subset of materials with novel, and often tunable, properties such as high strength, high toughness, and resistance to wear or corrosion. Often fabricated using alternating layers of two or more materials, these multilayer thin film coatings are typically expensive and time intensive to fabricate and characterize and exhibit novel responses to nanomechanical testing such as plasticity during unloading. This thesis explores the nanoindentation response of hard/soft multilayer coatings through examination of the optical coating Al/SiC and similar coating Al/SiO2. Instrumented indentation was used to study single layer films of aluminum, silicon carbide, and silicon dioxide with thicknesses 40nm to 4μm. Results from individual and cyclic indentation load cycles provided insight into film mechanical properties. Additionally alternating 51 layers hard/soft multilayers on silicon and quartz substrates were studied with spherical and Berkovich indenters. These multilayer films were fabricated with bilayer thickness of 160nm but variable thickness ratio to achieve 25, 50, and 75% aluminum by volume. Further microstructural characterization is necessary to fully explain the indentation behavior, however an accurate prediction of indentation derived modulus for the nanolaminate based upon monolayer properties was found. Furthermore, cyclic indentation of the nanolaminates along with post-indentation TEM led to the conclusion that unloading plasticity was not occurring within the multilayer structure or the effect was not significantly altering the indentation response. Finite element simulations were created to model individual load cycles for each combination of indenter, thickness ratio, film material, and substrate using ABAQUS. Single layer and multilayer simulations exhibited plastic deformation increasing within the aluminum layers during the unloading phase of indentation for all cases. Further simulation was conducted focusing on the cyclic indentation of aluminum thin films and Al/SiC nanolaminates. It was concluded that the simulation adequately represented the single material film responses but were unable to predict the indentation-derived properties for the Al/SiC multilayer. Further investigation would benefit from knowledge of the ceramic microstructure and viscous properties

Evaluación de las principales pérdidas que afectan al OEE de una máquina papelera modelo Recard, Lima 2018

RESUMEN La globalización, el crecimiento poblacional y la tendencia de los usuarios al buscar productos innovadores y de calidad, hace que las empresas estén en crecimiento constante, garantizando que los productos cumplan con las condiciones y estándares requeridos por los clientes. Hoy las empresas tienen la necesidad de mejorar continuamente de manera sistemática. La empresa en estudio se dedica a la fabricación y comercialización de productos de papel tisú tales como servilleta, papel toalla y papel higiénico. De enero a setiembre del año 2018 una de las máquinas de esta empresa denominada máquina papelera RECARD, ha tenido una tendencia de oee por debajo del objetivo de 93%, en el 2017 tuvo un oee promedio de 90.83% y de enero a setiembre del 2018 un oee de 87.9%. En la presente investigación se utilizó como referencia los datos del Performance Cubed un software en el que los operadores de máquina registran los minutos y motivos de pérdidas y el cual arroja como indicador el oee de máquina. El impacto en el periodo mencionado de enero a setiembre fue de $. 735 577.97 dólares (USD), el cual fue causado por distintitos motivos de parada. entre los que destacan: pérdida de velocidad, averías, paradas menores y cambios. Posteriormente se procede a analizar cada motivo de parada haciendo uso de las herramientas de ingeniería muy conocidas como son: Diagramas de pareto conocida también como 80/20 y diagramas causa-raíz (Ishikawa) para poder realizar un análisis exhaustivo de cada uno de los motivos de pérdida y llegar a la causa raíz. De las causas halladas se pudo determinar que los motivos que ocasionan fallas de los equipos son: falta de inspecciones, chequeos preventivos por parte del área de mantenimiento y la falta de: limpieza, inspecciones del personal de operación

Prevalence of gastro-esophageal reflux symptoms and associated factors : a population survey in the principal cities of Colombia

Problema: el reflujo gastroesofágico es un proceso fisiológico que en algunas personas puede tornarse pato-lógico y que produce molestias y lesiones esofágicas y extraesofágicas que afectan la calidad de vida de los individuos que lo presentan. Actualmente no se cuenta con estadísticas sobre la frecuencia de esta condición en Colombia. Objetivo: cuantificar la prevalencia de síntomas de enfermedad por reflujo gastroesofágico (ERGE) en los adultos de cuatro ciudades principales de Colombia utilizando el cuestionario GERDQ, y explorar la asociación de variables sociodemográficas y antropométricas con esta enfermedad. Metodología: estudio de corte transversal de base poblacional. Se incluyeron 6842 personas, mayores de 18 años y menores de 80 años de edad, residentes en Bogotá, Cali, Medellín y Barranquilla. La muestra fue seleccionada por muestreo aleatorio estratificado. Se aplicó una encuesta telefónica que incluía el cues-tionario GERDQ para la identificación de síntomas de reflujo en la última semana. Se calculó la prevalencia de reflujo por estratos teniendo en cuenta el punto de corte de la encuesta (8 o más puntos) y se realizaron comparaciones entre ellos utilizando la prueba de x2. Se exploró la asociación de variables sociodemográfi-cas y antropométricas mediante análisis bivariados y modelos de regresión logística. Resultados: se obtuvieron 6842 encuestas. La prevalencia estimada de síntomas de reflujo en general fue del 11,98% (IC 95%: 11,05-12,97). En el análisis por ciudades, Barranquilla presentó la frecuencia más alta (16,22%; IC 95%: 14,58-18,01) y Bogotá, la más baja (10,75; IC 95%: 9,30-12,38). Para los síntomas evaluados con el cuestionario GERDQ, la prevalencia estimada fue: pirosis, 13,6% (IC 95%: 12,50-14,60); regurgitación, 16,9% (IC 95%: 15,74-17,99); epigastralgia, 16,67% (IC 95%: 15,54-17,80): náuseas, 11,4% (IC 95%: 10,46-12,35); dificultad para dormir por presentar pirosis o regurgitación, 8,17% (IC 95%: 7,36-8,97); y consumo de medicamentos adicionales a los formulados por el médico, 6,68% (IC 95%: 6,01-7,35). El sexo femenino, el vivir en Barranquilla o Medellín y el presentar una comorbilidad se asociaron estadísticamente con la presencia de reflujo. Conclusión: la prevalencia de síntomas de reflujo en cuatro ciudades capitales de Colombia, medida con el cuestionario GERDQ, de 11,98% (IC 95%: 11,05-12,97), es similar a la reportada en otros países de Latinoamérica, siendo las comorbilidades (particularmente hipertensión arterial [HTA]) el factor que más se asoció con esta condición en todos los estratos del estudio.Q4Problem: Gastroesophageal reflux is a physiological process that can become pathological in some people. It can cause discomfort and esophageal and extra-esophageal injuries and can affect the quality of life of anyone affected by it. Currently there are no statistics on the frequency of this condition in Colombia. Objective: The objective of this study was to use the GerdQ questionnaire to quantify the prevalence of gastroesophageal reflux disease symptoms in adults in four major cities of Colombia and to explore the association of sociodemographic and anthropometric variables with this disease. Methodology: This was a cross-sectional population-based study of 6,842 people between the ages of 18 years and 80 in Bogotá, Cali, Medellín and Barranquilla. The sample was selected by stratified random sampling. A telephone survey was conducted that included the GERD Q questionnaire for the identification of reflux symptoms within the week prior to an interview. The prevalence of reflux by socioeconomic strata was calculated using a cut-off point of 8 or more points. Comparisons were made among strata using the χ2 test. Associations of sociodemographic and anthropometric variables were explored through bivariate analysis and logistic regression models. Results: We obtained 6,842 surveys. The overall estimated prevalence of reflux symptoms was 11.98% (95% CI = 11.05%-12.97%). The city of Barranquilla presented the highest frequency of 16.22% (95% CI = 14.58%-18.01%) while Bogotá had the lowest of 10.75% (95% CI = 9.30%-12.38%). For symptoms evaluated with GERD-Q, the estimated prevalences were: heartburn 13.6% (95% CI = 12.50% - 14.60%), regurgitation 16.9% (95% CI = 15, 74% - 17.99%), epigastralgia 16.67% (95% CI = 15.54% -17.80%), nausea 11.4% (95% CI = 10.46% - 12.35%), difficulty sleeping due to heartburn or regurgitation 8.17% (95% CI = 7.36% -8.97%) and consumption of medications additional to those formulated by the physician 6.68% (95% CI = 6, 01% - 7.35%). Women living in Barranquilla or Medellín, had statistically significant levels of comorbidities associated with reflux. Conclusion: The prevalence of reflux symptoms in four important Colombian cities measured with the GerdQ questionnaire was 11.98% (95% CI = 11.05-12.97) which is similar to prevalences reported in other Latin American countries. Comorbidities (particularly hypertension) are the factor that was most frequently associated with this condition in all strata of the study.Revista Nacional - Indexad

The Experiment for Space Radiation Analysis: Probing the Earth\u27s Radiation Belts Using a CubeSat Platform

The Experiment for Space Radiation Analysis (ESRA) is the latest of a series of Demonstration and Validation missions built by the Los Alamos National Laboratory, with the focus on testing a new generation of plasma and energetic particle sensors. The primary motivation for the ESRA payloads is to minimize size, weight, power, and cost while still providing necessary mission data. These new instruments will be demonstrated by ESRA through testing and on-orbit operations to increase their technology readiness level such that they can support the evolution of technology and mission objectives. This project will leverage a commercial off-the-shelf CubeSat avionics bus and commercial satellite ground networks to reduce the cost and timeline associated with traditional DemVal missions. The system will launch as a ride share with the DoD Space Test Program to be inserted in Geosynchronous Transfer Orbit (GTO) and allow observations of the Earth’s radiation belts. The ESRA CubeSat consists of two science payloads and several subsystems: the Wide-field-of-view Plasma Spectrometer, the Energetic Charged Particle telescope, high voltage power supply, payload processor, flight software architecture, and distributed processor module. The ESRA CubeSat will provide measurements of the plasma and energetic charged particle populations in the GTO environment for ions ranging from ~100 eV to ~1000 MeV and electrons with energy ranging from 100 keV to 20 MeV. ESRA will utilize a commercial 12U bus and demonstrate a low-cost, rapidly deployable spaceflight platform with sufficient SWAP to enable efficient measurements of the energetic particle populations in the dynamic radiation belts

SCIPP: An Expanded Community of Practice - Community Publishing

SCIPP redefines and expands the existing notions about what makes for a vibrant and robust community of practice by partnering CSUSB students and professors with K-12 students, parents, and educators, along with committed community partners. SCIPP encourages curiosity in ways that leads to critical thinking, exploration, risk taking , confidence building, open-mindedness, and other personal traits that equip them with the softskills to be active, critical, and creative contributors to our communities. SCIPP pedagogy embraces our students\u27 collective wisdom and focuses on relational building where multi-directional communication is promoted and students are viewed as equal stakeholders in their own educations. SCIPP puts collaboration into action which in turn fosters community-based lifelong learning. SCIPP provides the open intellectual space for future university students (our K-12 students) to engage with existing university students in meaningful ways so as to sustain interconnected partnerships facilitating community engagement. It supports parents as experts in the education of their children and acknowledges parents as the first conduits to spark their children’s imagination while they actively participate in education enriching activities and programs. Everyone involved is committed to creating a secure and open atmosphere for dreaming, sharing, and learning. Together we explore the aspects of community publishing through collaborative learning in formal and informal settings relating to digital and printed medias

The SuperCam Instrument Suite on the Mars 2020 Rover: Science Objectives and Mast-Unit Description

On the NASA 2020 rover mission to Jezero crater, the remote determination of the texture, mineralogy and chemistry of rocks is essential to quickly and thoroughly characterize an area and to optimize the selection of samples for return to Earth. As part of the Perseverance payload, SuperCam is a suite of five techniques that provide critical and complementary observations via Laser-Induced Breakdown Spectroscopy (LIBS), Time-Resolved Raman and Luminescence (TRR/L), visible and near-infrared spectroscopy (VISIR), high-resolution color imaging (RMI), and acoustic recording (MIC). SuperCam operates at remote distances, primarily 2-7 m, while providing data at sub-mm to mm scales. We report on SuperCam's science objectives in the context of the Mars 2020 mission goals and ways the different techniques can address these questions. The instrument is made up of three separate subsystems: the Mast Unit is designed and built in France; the Body Unit is provided by the United States; the calibration target holder is contributed by Spain, and the targets themselves by the entire science team. This publication focuses on the design, development, and tests of the Mast Unit; companion papers describe the other units. The goal of this work is to provide an understanding of the technical choices made, the constraints that were imposed, and ultimately the validated performance of the flight model as it leaves Earth, and it will serve as the foundation for Mars operations and future processing of the data.In France was provided by the Centre National d'Etudes Spatiales (CNES). Human resources were provided in part by the Centre National de la Recherche Scientifique (CNRS) and universities. Funding was provided in the US by NASA's Mars Exploration Program. Some funding of data analyses at Los Alamos National Laboratory (LANL) was provided by laboratory-directed research and development funds

Impacts of the Tropical Pacific/Indian Oceans on the Seasonal Cycle of the West African Monsoon

The current consensus is that drought has developed in the Sahel during the second half of the twentieth century as a result of remote effects of oceanic anomalies amplified by local land–atmosphere interactions. This paper focuses on the impacts of oceanic anomalies upon West African climate and specifically aims to identify those from SST anomalies in the Pacific/Indian Oceans during spring and summer seasons, when they were significant. Idealized sensitivity experiments are performed with four atmospheric general circulation models (AGCMs). The prescribed SST patterns used in the AGCMs are based on the leading mode of covariability between SST anomalies over the Pacific/Indian Oceans and summer rainfall over West Africa. The results show that such oceanic anomalies in the Pacific/Indian Ocean lead to a northward shift of an anomalous dry belt from the Gulf of Guinea to the Sahel as the season advances. In the Sahel, the magnitude of rainfall anomalies is comparable to that obtained by other authors using SST anomalies confined to the proximity of the Atlantic Ocean. The mechanism connecting the Pacific/Indian SST anomalies with West African rainfall has a strong seasonal cycle. In spring (May and June), anomalous subsidence develops over both the Maritime Continent and the equatorial Atlantic in response to the enhanced equatorial heating. Precipitation increases over continental West Africa in association with stronger zonal convergence of moisture. In addition, precipitation decreases over the Gulf of Guinea. During the monsoon peak (July and August), the SST anomalies move westward over the equatorial Pacific and the two regions where subsidence occurred earlier in the seasons merge over West Africa. The monsoon weakens and rainfall decreases over the Sahel, especially in August.Peer reviewe

Search for heavy resonances decaying to two Higgs bosons in final states containing four b quarks

A search is presented for narrow heavy resonances X decaying into pairs of Higgs bosons (H) in proton-proton collisions collected by the CMS experiment at the LHC at root s = 8 TeV. The data correspond to an integrated luminosity of 19.7 fb(-1). The search considers HH resonances with masses between 1 and 3 TeV, having final states of two b quark pairs. Each Higgs boson is produced with large momentum, and the hadronization products of the pair of b quarks can usually be reconstructed as single large jets. The background from multijet and t (t) over bar events is significantly reduced by applying requirements related to the flavor of the jet, its mass, and its substructure. The signal would be identified as a peak on top of the dijet invariant mass spectrum of the remaining background events. No evidence is observed for such a signal. Upper limits obtained at 95 confidence level for the product of the production cross section and branching fraction sigma(gg -> X) B(X -> HH -> b (b) over barb (b) over bar) range from 10 to 1.5 fb for the mass of X from 1.15 to 2.0 TeV, significantly extending previous searches. For a warped extra dimension theory with amass scale Lambda(R) = 1 TeV, the data exclude radion scalar masses between 1.15 and 1.55 TeV