21,987 research outputs found

    Modelling uncertainties for measurements of the H → γγ Channel with the ATLAS Detector at the LHC

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    The Higgs boson to diphoton (H → γγ) branching ratio is only 0.227 %, but this final state has yielded some of the most precise measurements of the particle. As measurements of the Higgs boson become increasingly precise, greater import is placed on the factors that constitute the uncertainty. Reducing the effects of these uncertainties requires an understanding of their causes. The research presented in this thesis aims to illuminate how uncertainties on simulation modelling are determined and proffers novel techniques in deriving them. The upgrade of the FastCaloSim tool is described, used for simulating events in the ATLAS calorimeter at a rate far exceeding the nominal detector simulation, Geant4. The integration of a method that allows the toolbox to emulate the accordion geometry of the liquid argon calorimeters is detailed. This tool allows for the production of larger samples while using significantly fewer computing resources. A measurement of the total Higgs boson production cross-section multiplied by the diphoton branching ratio (σ × Bγγ) is presented, where this value was determined to be (σ × Bγγ)obs = 127 ± 7 (stat.) ± 7 (syst.) fb, within agreement with the Standard Model prediction. The signal and background shape modelling is described, and the contribution of the background modelling uncertainty to the total uncertainty ranges from 18–2.4 %, depending on the Higgs boson production mechanism. A method for estimating the number of events in a Monte Carlo background sample required to model the shape is detailed. It was found that the size of the nominal γγ background events sample required a multiplicative increase by a factor of 3.60 to adequately model the background with a confidence level of 68 %, or a factor of 7.20 for a confidence level of 95 %. Based on this estimate, 0.5 billion additional simulated events were produced, substantially reducing the background modelling uncertainty. A technique is detailed for emulating the effects of Monte Carlo event generator differences using multivariate reweighting. The technique is used to estimate the event generator uncertainty on the signal modelling of tHqb events, improving the reliability of estimating the tHqb production cross-section. Then this multivariate reweighting technique is used to estimate the generator modelling uncertainties on background V γγ samples for the first time. The estimated uncertainties were found to be covered by the currently assumed background modelling uncertainty

    Electric Energy Transmission Processes and the Importance of Integrated System Management and Operation

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    La energía eléctrica es fundamental en diferentes sectores del desarrollo de una sociedad; dado que se utiliza en todo tipo de industrias y sectores económicos y es fundamental en nuestros hogares, por lo que el acceso a un servicio de energía eléctrica de calidad en la ciudad o en las zonas rurales proporciona un índice de referencia del nivel de desarrollo de un territorio. Por esta razón, la transmisión de energía eléctrica se considera uno de los factores más relevantes para mejorar la calidad de vida de los habitantes de un país con alto índice de pobreza. La energía eléctrica es un servicio que debe transmitirse de manera garantizada con altos estándares de calidad, confiabilidad y disponibilidad. Esto apoya el desarrollo económico de una nación. Esta investigación se enfocó en estudiar la eficiencia de una organización que brinda el servicio de transformación y transporte de energía eléctrica en Colombia y a través de este estudio impactar a profesionales, instituciones de educación superior y empresas para asegurar su presencia en el mercado y en paralelo brindar a las empresas una guía que permita a las organizaciones dedicadas al sector eléctrico en Colombia cumplir con la normativa vigente. Este trabajo destaca la necesidad de realizar procesos mecánicos, eléctricos, instrumentales, operacionales y de gestión con altos estándares para las empresas que brindan servicio de transmisión de energía eléctrica con equipos que operan a tensiones superiores a 220 kV. Adicionalmente, esta investigación tiene como objetivo establecer una guía que permita a las organizaciones dedicadas al sector eléctrico en Colombia cumplir con la normativa vigenteElectric energy is fundamental in different sectors of a society's development; electric energy is used in all types of industries and economic sectors and is essential in people's homes, so access to a quality electric energy service in the city or in rural areas provides a reference index of a territory's level of development. For this reason, electricity transmission is considered one of the most relevant factors for improving the quality of life of the inhabitants of a country with a high poverty index. Electric power is a service that must be transmitted in a guaranteed manner with high standards of quality, reliability, and availability. This supports the economic development of a nation. This research focused on studying the efficiency of an organization that provides the service of transformation and transportation of electrical energy in Colombia and through this study to impact professionals, higher education institutions and companies to ensure their presence in the market, improving the quality of their graduates in different areas of knowledge such as physics and engineering and in parallel to provide companies with a guide that allows organizations dedicated to the electricity sector in Colombia to comply with existing regulations. This work highlights the need to perform mechanical, electrical, instrumental, operational and management processes with high standards for companies that provide electric power transmission service with equipment operating at voltages above 220 kV. Additionally, this research aims to establish a guide that allows organizations dedicated to the electric sector in Colombia to comply with current regulations

    Upgrading Urban Services Through BPL: Practical Applications for Smart Cities

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    Current initiatives related to smart cities in LATAM reveal an increasing interest in the improvement of cities and the wellbeing of their citizens. In addition, specific working groups have been created for this purpose. In this sense, the communication technologies set the basis for gathering, transporting, and managing the large amount of data generated in cities to provide a wide range of services. Within the many alternatives available, BPL positions as a promising technology, since smart cities can greatly benefit of its higher data rates and low latency. In addition, since the medium is already deployed and most of the assets and sensors are connected to the same medium, the cost of the communication systems will be reduced in price and simplicity. The work presents four practical applications: smart buildings, urban lighting, energy assets management and broadband access, in which the possibilities and advantages of BPL are further addressed. Finally, some conclusions and key aspects relating BPL to the success of smart cities are identified.Eusko Jaurlaritza IT-1234-19, KK-202

    CO2 electroreduction: sustainability analysis of the renewable synthetic natural gas

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    Capture and utilization of industrial CO2 emissions into low-carbon fuels is a promising alternative to store renewable electricity into chemical vectors while decarbonizing the economy. This work evaluates the viability pathways of producing synthetic natural gas (SNG) by direct CO2 electroreduction (ER) in Power-To-Synthetic Natural Gas electrolyzers (PtSNG). We perform an ex-ante techno-economic (TEA) and life cycle analysis (LCA) for a 2030 framework in Europe. ER performance is varied in defined scenarios and assessed using a built-in process model of the PtSNG system, revealing uncharted limitations and benchmarks to achieve. Results show that substitution of fossil natural gas with renewable SNG could avoid more than 1 kg CO2e/kg SNG under moderate ER conditions when using low-carbon electricity (< 60 kg CO2e/MWh). SNG profitability for 2030 would rely on: i) higher CH4 current densities (800–1000 mA/cm2), ii) improvements in energy efficiency (higher than 60%), and iii) valorization of the anodic product or additional carbon incentives. Our study proves that if market and technology evolve appropriately in the coming years, the SNG by CO2 ER may be a mid-term climate change mitigation technology, among others.The authors thank the Spanish Ministry of Economy and Competitiveness for the financial support through the project PID2020–114,787-RB-I00. Javier Fernández-González and Marta Rumayor would also like to thank the financial support of the Spanish Ministry of Science and Innovation for the concession of a FPU grant (FPU19/05483) and a Juan de la Cierva postdoctoral contract (IJCI-2017-32621), respectively

    Evaluación de AIoT en modelos computacionales en la nube y en el borde aplicado a la detección de mascarillas

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    COVID-19 has caused serious health damage, infecting millions of people and unfortunately causing the death of several ones around the world. The vaccination programs of each government have influenced in declining those rates. Nevertheless, new coronavirus mutations have emerged in different countries, which are highly contagious, causing concern with vaccination effectiveness. So far, wearing facemasks in public continues being the most effective protocol to avoid and prevent COVID-19 spread. In this context, there is a demand of automatic facemask detection services to remind people the importance of wearing them appropriately. In this work, a performance evaluation of an AIoT system to detect correct, inappropriate, and non- facemask wearing, based on two computational models: Cloud and Edge, was conducted. Having as objective to determine which model better suites a real environment (indoor and \emph{outdoor}), based on: reliability of the detector algorithm, use of computational resources, and response time. Experimental results show that Edge-implementation got better performance in comparison to Cloud-implementation.La COVID-19 ha provocado graves daños a la salud: centenas de millones de personas infectadas y varios millones de fallecidos en el mundo. Los programas de vacunación de cada Gobierno han influido en el decaimiento de estos índices, pero con la aparición de nuevas mutaciones del coronavirus más contagiosas, la preocupación sobre la efectividad de las vacunas se hace presente. Frente a esta situación el uso de mascarillas sigue siendo eficaz para prevenir la transmisión y contagio de la COVID-19. Lo que ha generado una creciente demanda de servicios de detección automática de mascarillas, que permita recordar a las personas la importancia del empleo de estas. En este trabajo se plantea un análisis del rendimiento de un sistema AIoT para la detección del uso correcto, incorrecto y sin mascarilla basado en dos modelos computacionales de Cloud y Edge, con la finalidad de determinar qué modelo se adecua mejor en un entorno real (interior y exterior) sobre la base de la confiabilidad del algoritmo, uso de recursos computacionales y tiempo de respuesta. Los resultados experimentales demuestran que el modelo computacional Edge presentó un mejor desempeño en comparación con el Cloud

    Ionic Liquids on Oxide Surfaces

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    Ionic liquids supported on oxide surfaces are being investigated for numerous applications including catalysis, batteries, capacitors, transistors, lubricants, solar cells, corrosion inhibitors, nanoparticle synthesis and biomedical applications. The study of ionic liquids with oxide surfaces presents challenges both experimentally and computationally. The interaction between ionic liquids and oxide surfaces can be rather complex, with defects in the oxide surface playing a key role in the adsorption behaviour and resulting electronic properties. The choice of the cation/anion pair is also important and can influence molecular ordering and electronic properties at the interface. These controllable interfacial behaviours make ionic liquid/oxide systems desirable for a number of different technological applications as well as being utilised for nanoparticle synthesis. This topical review aims to bring together recent experimental and theoretical work on the interaction of ionic liquids with oxide surfaces, including TiO2, ZnO, Al2O3, SnO2 and transition metal oxides. It focusses on the behaviour of ionic liquids at model single crystal surfaces, the interaction between ionic liquids and nanoparticulate oxides, and their performance in prototype devices

    Facile cellulase immobilisation on bioinspired silica

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    Cellulases are enzymes with great potential for converting biomass to biofuels for sustainable energy. However, their commercial use is limited by their costs and low reusability. Therefore, the scientific and industrial sectors are focusing on finding better strategies to reuse enzymes and improve their performance. In this work, cellulase from Aspergillus niger was immobilised through in situ entrapment and adsorption on bio-inspired silica (BIS) supports. To the best of our knowledge, this green effect strategy has never been applied for cellulase into BIS. In situ entrapment was performed during support synthesis, applying a one-pot approach at mild conditions (room temperature, pH 7, and water solvent), while adsorption was performed after support formation. The loading efficiency was investigated on different immobilisation systems by Bradford assay and FTIR. Bovine serum albumin (BSA) was chosen as a control to optimize cellulase loading. The residual activity of cellulase was analysed by the dinitro salicylic acid (DNS) method. Activity of 90% was observed for the entrapped enzyme, while activity of ~55% was observed for the adsorbed enzyme. Moreover, the supported enzyme systems were recycled five times to evaluate their reuse potential. The thermal and pH stability tests suggested that both entrapment and adsorption strategies can increase enzyme activity. The results highlight that the entrapment in BIS is a potentially useful strategy to easily immobilise enzymes, while preserving their stability and recycle potential

    In search of 'The people of La Manche': A comparative study of funerary practices in the Transmanche region during the late Neolithic and Early Bronze Age (250BC-1500BC)

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    This research project sets out to discover whether archaeological evidence dating between 2500 BC - 1500 BC from supposed funerary contexts in Kent, flanders and north-eastern Transmanche France is sufficient to make valid comparisons between social and cultural structures on either side of the short-sea Channel region. Evidence from the beginning of the period primarily comes in the form of the widespread Beaker phenomenon. Chapter 5 shows that this class of data is abundant in Kent but quite sparse in the Continental zones - most probably because it has not survived well. This problem also affects the human depositional evidence catalogued in Chapter 6, particularly in Fanders but also in north-eastern Transmanche France. This constricts comparative analysis, however, the abundant data from Kent means that general trends are still discernible. The quality and volume of data relating to the distribution, location, morphology and use of circular monuments in all three zones is far better - as demonstrated in Chapter 7 -mostly due to extensive aerial surveying over several decades. When the datasets are taken as a whole, it becomes possible to successfully apply various forms of comparative analyses. Most remarkably, this has revealed that some monuments apparently have encoded within them a sophisticated and potentially symbolically charged geometric shape. This, along with other less contentious evidence, demonstrates a level of conformity that strongly suggests a stratum of cultural homogeneity existed throughout the Transmanche region during the period 2500 BC - 1500 BC. The fact that such changes as are apparent seem to have developed simultaneously in each of the zones adds additional weight to the theory that contact throughout the Transmanche region was endemic. Even so, it may not have been continuous; there may actually have been times of relative isolation - the data is simply too course to eliminate such a possibility
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