QUANTIFYING THE EFFECT OF CONSTRUCTION SITE FACTORS ON CONCRETE QUALITY, COSTS AND PRODUCTION RATES

Factors affecting concrete can be categorized as structured factors or unstructured factors. The first group of factors consists of those related to the production process of concrete including water-cement ratio, properties of raw materials and mix proportions. Unstructured factors or construction site factors are related to labor skills and local conditions during the construction process of a project. Concrete compressive strength as a quality metric, costs and production rates may be affected significantly by such factors while performing concrete operations at the jobsite. Several prior studies have investigated the effect of structured factors on concrete. However literature is limited regarding the effects of unstructured factors during the construction phase of a facility. This study proposes a systematic methodology to identify and quantify the effects of construction site factors including crew experience, compaction method, mixing time, curing humidity and curing temperature on concrete quality, costs and production rates using fuzzy inference systems. First, the perceived importance of construction-related factors is identified and evaluated through literature review and a survey deployed to construction experts. Then, the theory of design of experiments (DOE) is used to conduct a full 25 factorial experiment consisting of 32 runs and 192 compressive strength tests to identify statistically significant unstructured factors. Fuzzy inference systems (FISs) are proposed for predicting concrete compressive strength, costs and production rate effects through the use of adapted network-based fuzzy inference system (ANFIS). Finally, an optimization model is formulated and tested for managing concrete during the construction process of a facility. Literature review and survey results showed that curing humidity, crew experience, and compaction method are the top three factors perceived by construction experts to affect concrete compressive strength, whereas crew experience, mixing time and compaction method are the top three factors affecting concrete costs and production rates. Additionally, crew experience, compaction and mixing time were found to dominate global ranking of perceived affecting factors through the application of the relative importance index (RII). When conducting designed experiments and analysis of variance (ANOVA), compaction method, mixing time, curing humidity and curing temperature were identified to be statistically significant construction site factors for concrete compressive strength whereas crew experience, compaction method and mixing time were statistically significant factors for cost and production rates. A Sugeno type fuzzy inference system (FIS) for quantifying compressive strength, cost and production rate effects was created by using ANFIS, having correlation coefficients (R-squared values) greater than 93%, indicating that resulting models predict new observations well. Curing temperature (i.e., on-site curing temperature) was identified to be the most affecting condition for concrete compressive strength while mixing time had the biggest impact on concrete cost and production rates. The developed FISs can be used as a decision–support tool that allows for determining desired operating conditions, that ensures specified compressive strength, saves resources and maximizes profits when fabricating, placing and curing concrete

Perceptions on construction-related factors that affect concrete quality, costs and production

Structured and unstructured factors affect concrete product. Structured factors are related to concrete production and unstructured factors are related to the construction process. This study focuses on examining the perceived importance of unstructured factors (i.e., construction-related factors) on concrete compressive strength, concrete costs and production rates on the jobsite and understanding the influence of construction experts’ characteristics, such as profession, on their perceptions. A comprehensive literature review was performed to identify unstructured factors. A survey was then designed and deployed to 297 experts from the construction industry and academia to examine the importance of the identified factors through the relative importance index (RII) method and to further identify additional unstructured factors. Likert aggregation and tests for equality of odds were used to compare and analyze responses of two groups of participants, namely architects and engineers. Curing humidity, crew experience and compaction method are the top three factors perceived to affect concrete compressive strength, whereas crew experience, mixing time and compaction method are the factors perceived to affect concrete costs and production rates the most. Crew experience, compaction method and mixing time dominate the global ranking of perceived affecting factors for concrete compressive strength, costs and production rates. Architects were found to be more likely to perceive high or very high impacts of these factors on concrete. The present study increases our understanding of construction-related factors to facilitate project management and preserve concrete characteristics

PLAN ESTRATEGICO DE TECNOLOGIAS DE INFORMACION PARA VALORAR EL NIVEL DE COMPETENCIAS DIGITALES EN DOCENTES DEL COLEGIO NACIONAL DE SAN JOSE, 2019

Las competencias digitales se definen como un espectro de competencias que facilitan el uso de los dispositivos digitales, las aplicaciones de la comunicación y las redes para acceder a la información y llevar a cabo una mejor gestión de éstas. Lamentablemente, en la actualidad, en el Colegio Nacional San José existe una brecha de conocimiento en lo referente a este tema y es por ello que se planteó esta investigación; la cual buscó responder ¿De qué manera un plan estratégico en tecnologías de información permitirá potenciar las competencias digitales de docentes del Colegio Nacional de San José, 2019? Para dar respuesta a ello se estableció como objetivo principal el diseñar un plan estratégico en tecnologías de información para potenciar las competencias digitales de docentes en base a los niveles de competencias digitales hallados en los docentes y las brechas digitales. Finalmente se obtuvo como producto un PETI a través del cual no solo se evaluó la situación tecnológica del colegio sino además se establecieron los proyectos que deberían de desarrollarse para dar soporte a los objetivos estratégicos de la institución y reducir la brecha de conocimiento existente.Tesi

Sistema Bitufor para reducir reflexión de grietas y prolongar vida útil de un pavimento flexible Villa María del Triunfo, 2022

El presente proyecto de investigación tiene como objetivos general analizar si la aplicación del sistema bitufor reduce la reflexión de un pavimento flexible villa María del Triunfo, 2022, utilizando una metodología de tipo experimental yaqué los datos se van a obtener con la experimentación y manipulación de las variables, de tipo aplicada y un enfoque cuantitativo, para los cuales se usaron instrumentos tales como: normas técnicas, equipo de laboratorio para los ensayos y uso de fórmulas mediante hojas de datos, teniendo como población el jr. jorge Chávez en san Gabriel VMT, en cuanto a la muestra jirón jorge Chávez que se tomó desde la calle manco inca hasta la Av. José Carlos Mariátegui y teniendo un muestreo no probabilístico. En cuanto a los resultados primero se procedió a realizar el cálculo del IMDA para poder saber cuántas o que profundidad debería de realizarse las calicatas, la cual dio una calicata de 1.5m, posteriormente se llevó a laboratorio la muestra para poder analizar el tipo de suelo y todo lo que presenta este, dando como resultado que es una arena pobremente gravada con limo, posteriormente se realizó el ensayo Proctor modificado para poder obtener la máxima densidad seca y el óptimo contenido de humedad, luego se procedió a realizar el ensayo de C.B.R el cual nos dio la resistencia en la subrasante, sub base y base, para poder realizar el diseño y posteriormente realizar el Ensayo Marshall en el cual se realizaron 10 briquetas con pavimento flexible natural y 10 briquetas con pavimento flexible utilizando el sistema bitufor, el cual mediante el ensayo Marshall nos dio los resultados que el pavimento flexible mediante el sistema bitufor presenta una mejora en la estabilidad y en la relación estabilidad/flujo el cual nos da una mejora y se recomienda su aplicación de este mismo

Influencia del bullying en el clima del aula en estudiantes de una institución educativa en Pachacamac-2023

El objetivo fue determinar la influencia del bullying en el clima del aula en estudiantes de una institución educativa en Pachacamac-2023. El enfoque fue cuantitativo, tipo básica, diseño no experimental, explicativa causal. La muestra fue de 126 estudiantes, la técnica fue la encuesta y el instrumento el cuestionario, también se realizó el cálculo de confiabilidad de Alfa de Cronbach para bullying fue de 0,894 y para el clima del aula fue de 0,916, respecto a la validez de contenido se realizó a través del juicio de tres expertos. Los resultados comprobaron que basado en los resultados del programa y los datos sintetizados en la tabla se tienen al estadístico de Nagelkerke de 4.7 % y p-valor = 0. 032 < 0.05, por tanto, se concluyó, que existe una influencia baja del bullying en el clima del aula en los estudiantes de una institución educativa en Pachacamac

Mediterranean rural landscapes: methodological guide for the implementation of a model of territorial governance

Guia metodològica de Bones Pràctiques de Paisatge en el marc del programa europeu INTEREG Modeland.Postprint (published version

Planeamiento de redes eléctricas en ciudades densamente pobladas. Con generación distribuida y compensación capacitiva

This paper analyses different options that can be used to solve the problem of the planning of power distribution networks by including capacitive compensation and distributed generation. The methodology for planning aims to determine the size of the units, the bus where the units have to be located, and the year in which investments should be made, in order to minimize the total energy losses on the network during the planning period. The work analyses four different cases: planning using neither capacitive compensation (SC) nor distributed generation (DG), planning using only SC, planning using only DG, and planning using reactive compensation and distributed generation simultaneously. Results show that simultaneous use of SC and DG reduce the total energy losses and improve the voltage profiles on the network, so good results for the planning are obtained.Este artículo analiza diferentes opciones para realizar planeamiento de redes eléctricas de distribución en zonas con gran densidad de población a través del uso de generación distribuida y compensación capacitiva. La metodología de planificación permite determinar el tamaño de la unidad a instalar, el nodo en que debe ser ubicada y el año en que se debe hacer la inversión, con el fin de minimizar las pérdidas de energía durante el periodo de planificación. El estudio evalúa cuatro casos que son: planificación sin compensación capacitiva (SC) y sin&nbsp; generación distribuida (DG),&nbsp; planificación usando SC, planificación usando DG, y planificación usando los dos elementos simultáneamente. Los resultados muestran que el uso simultáneo de SC y DG disminuye las pérdidas totales de energía y mejora los perfiles de tensión en los nodos de la red, con&nbsp; lo cual se obtienen muy buenos resultados en el planeamiento

Mediterranean rural landscapes: Guide of best landescape practices and pilot actions

Postprint (published version

Implementation of a building automation system based on semantic modeling

This paper presents an Ontology-Based multi-technology platform designed to avoid some issues of Building Automation Systems. The platform allows the integration of several building automation protocols, eases the development and implementation of different kinds of services and allows sharing information related to the infrastructure and facilities within a building. The system has been implemented and tested in the Energy Efficiency Research Facility at CeDInt-UPM

Removal of Paracetamol Using Effective Advanced Oxidation Processes

Fenton, photo-Fenton, and photo-induced oxidation, were investigated and compared for the treatment of 0.26 mmol L-1 of paracetamol (PCT) in a deionised water matrix, during a reaction span of 120.0 min. Low and high Fenton reagent loads were studied. Particularly, the initial concentration of Fe2+ was varied between 0.09 and 0.18 mmol L-1 while the initial concentration of H2O2 was varied between 2.78 and 11.12 mmol L-1. The quantitative performance of these treatments was evaluated by: (i) measuring PCT concentration; (ii) measuring and modelling TOC conversion, as a means characterizing sample mineralization; and (iii) measuring cytotoxicity to assess the safe application of each treatment. In all cases, organic matter mineralization was always partial, but PCT concentration fell below the detection limit within 2.5 and 20.0 min. The adopted semi-empirical model revealed that photo induced oxidation is the only treatment attaining total organic matter mineralization (¿MAX= 100% in 200.0 min) at the expense of the lowest kinetic constant (k = 0.007 min-1). Conversely, photo-Fenton treatment using high Fenton reagent loads gave a compromise solution (¿MAX= 73% and k = 0.032 min-1). Finally, cytotoxicity assays proved the safe application of photo-induced oxidation and of photo-Fenton treatments using high concentrations of Fenton reagents.Peer ReviewedPostprint (published version