Luis Manuel Navas Gracia

Luis Manuel Navas Gracia
Universidad de Valladolid | UVA · Department of Agricultural and Forestry Enginnering

About

135
Publications
65,097
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
1,250
Citations

Publications

Publications (135)
Article
Full-text available
This study evaluates the predictive modeling of the daily ambient temperature (maximum, Tmax; average, Tave; and minimum, Tmin) and its hourly estimation (T0h, …, T23h) using artificial neural networks (ANNs) for agricultural applications. The data, 2004–2010, were used for training and 2011 for validation, recorded at the SIAR agrometeorological s...
Article
Full-text available
Agrometeorological stations have horizontal solar irradiation data available, but the design and simulation of photovoltaic (PV) systems require data about the solar panel (inclined and/or oriented). Greenhouses for agricultural production, outside the large protected production areas, are usually off-grid; thus, the solar irradiation variable on t...
Book
Full-text available
07/10/2020: 1.- Conferencia Inaugural “La investigación en Ingeniería de Biosistemas en España y en la Universidad de Valladolid” Prof. L.M. Navas Gracia; 2.- Proyecto LIFE “Ammonia trapping”. Profª M. Sánchez Báscones, Dra. M.C. García González || 08/10/2020: 3.- Proyecto UIC 262 JCYL “Síntesis y validación de nuevos antifúngicos de origen natural...
Chapter
Full-text available
and Full-Text in: https://videleaf.com/anns-for-the-daily-prediction-of-horizontal-global-solar-irradiation-in-an-agrometeorological-station-with-mediterranean-warm-summer-climate/
Article
Full-text available
In this paper, the concept of Virtual Weather Stations (VWS) is introduced. A VWS is an integration of algorithms to download meteorological data, process and use them with the main objective of estimate data in nearby locations with no meteorological stations. To develop the VWS, the performances of different interpolation methods were evaluated t...
Article
Full-text available
Energy security on islands is a challenging issue due to their isolation from energy markets and fossil fuel dependence. In addition, islands’ average energy intensity has increased in recent years due to economic development. This research explores the environmental performance of two alternative non-variable bioelectricity feedstocks to increase...
Article
Full-text available
Unmanned Aerial Vehicles (UAVs) offer excellent survey capabilities at low cost to provide farmers with information about the type and distribution of weeds in their fields. In this study, the problem of detecting the infestation of a typical weed (charlock mustard) in an alfalfa crop has been addressed using conventional digital cameras installed...
Article
Full-text available
Estimation of chlorophyll content with portable meters is an easy way to quantify crop nitrogen status in sugar beet leaves. In this work, an alternative for chlorophyll content estimation using RGB-only vegetation indices has been explored. In a first step, pictures of spring-sown ‘Fernanda KWS’ variety sugar beet leaves taken with a commercial ca...
Article
Full-text available
This article evaluates horizontal daily global solar irradiation predictive modelling using artificial neural networks (ANNs) for its application in agricultural sciences and technologies. An eight year data series (i.e., training networks period between 2004–2010, with 2011 as the validation year) was measured at an agrometeorological station loca...
Article
Full-text available
Políticas públicas têm sido usadas em todo o mundo para promover o uso racional dos recursos naturais, incluindo instrumentos para compensação financeira. No Brasil, tem se destacado a lei do ICMS Ecológico, segundo a qual os estados repassam recursos para municípios que promovem ações socioambientais. Objetivou-se com este trabalho analisar o níve...
Article
Full-text available
The 450 Scenario, which limits the increase in global average temperature to 2 °C, makes it necessary to take steps towards a low-carbon economy. Since the energy sector is a major contribution to anthropogenic greenhouse gas (GHG) emissions, the production of biofuels can play a key role in strategies aimed at climate change mitigation. In this re...
Article
Full-text available
The impacts of climatic variables on the growth and carbon content of spring sown sugar beet (Beta vulgaris L.) in the Castilla y Leon region (Northwestern Spain) were assessed by analyzing 35 beet crop variables at four sites over two cultivation years. ANOVA analysis allowed to discern that the location was the factor that had the highest effect...
Article
Full-text available
The expansion of the production and use of bioenergy is one of the most efficient mechanisms to reduce greenhouse gas (GHG) emissions. Nevertheless, the environmental impact of the production processes for many raw materials remains unexplored. Several studies have pointed to macauba palm as a promising species for biofuel production in the tropics...
Conference Paper
Full-text available
The expansion of the production and use of bioenergy is deemed as one of the most efficient mechanisms to reduce greenhouse gas (GHG) emissions. Nevertheless, the environmental impact of the production processes for many raw materials remains unexplored. Several studies have pointed to macauba palm (Acrocomia aculeata (Jacq.) Lodd. ex Mart.) as a p...
Article
Active microalgae biomass from wastewater treatment may be given added value as a biofertilizer, but little is known about how this may affect soil nutrient dynamics and biology. If the goal is to recycle waste nutrients and matter, live algae applied in a liquid slurry to soil may add both organic carbon and nutrients while providing other benefit...
Article
Full-text available
The upsurge in fungal diseases that cause grapevine wood rot in young and adult plants remains a major concern for the wine sector. Since pruned vine shoots act as a reservoir of these fungi, there is a need for sanitization methods that can prevent their spread, avoiding plant reinfection. In this work, the effectiveness of dry heat treatments for...
Article
Full-text available
In this study an example of the reuse and revalorization of lignocellulosic waste from carnauba palm (Copernicia prunifera) leaves, macauba palm (Acrocomia aculeata) endocarp (shell) and European stone pine (Pinus pinea) nut shell is presented for the first time. The physical-chemical adsorption of Rhodamine B (RhB) dye for the different materials...
Article
Full-text available
Knowing the maturation of the Acrocomia aculeata (macaw palm) fruit is decisive for harvest to be performed when the fruit has a higher content and quality of oil. There are different approaches to monitor maturation and they can be classified as destructive and non-destructive. Variables obtained by optical instruments have been used to determine...
Article
Caracterización térmica y vibracional de las semillas, pulpa, hojas y aceite de semillas de Rosa rubiginosa. El aceite de semillas de R. rubiginosa L. ha sido estudiado para su aplicación en productos para el cuidado de la piel, pero la naturaleza química de las semillas, pulpa y hojas, además de la del aceite, también es importante con miras a la...
Article
Full-text available
After the ban on sodium arsenite, waste management alternatives to the prevalent burning method, such as the hygienization and biodegradation in solid phase by composting, are required for the pruned material from grapevines affected by various fungi. In this work the dynamics of a fungus associated with vine decay (Diplodia seriata) during the com...
Article
Full-text available
Different types of lignocellulosic materials (carnauba leaves, macauba shell and pine nut shell) and native cellulose have been studied for the production of total reducing sugars (TRS) through microwave-assisted acid-catalyzed hydrolysis in ionic liquids (ILs). Four reaction media have been assessed: two deep eutectic solvents (DES), choline chlor...
Article
The results of analyses of thermal stratification using different initial water temperature profiles are reported and discussed. Stratification proved to be the main factor in the cooling process, since although ambient temperature is also a determining factor, in this case it played a lesser role because the tank’s location inside the laboratory m...
Article
Full-text available
A reduced graphene oxide (rGO)/chitosan oligomers (CSO)/silver nanoparticle (AgNPs) composite was designed and prepared via a self-assembly process with rGO through a microwave-assisted method. The material, isolated as a nano-crystalline graphenic material, was characterized by ATR-FTIR and UV-Vis spectroscopies, X-ray powder diffraction, TEM micr...
Article
Full-text available
R. rubiginosa L. seed oil has been studied for its application in skin care products, but the chemical nature of seeds, pulp and even leaves, apart from that of oil, is also relevant with a view to the application of this weed for biodiesel production. All these vegetal materials were studied by infrared spectroscopy (FTIR) and differential scannin...
Book
Full-text available
En estos años de crisis y desaceleración económica estamos asistiendo a un grave deterioro de las condiciones de trabajo y a una reducción de los recursos dedicados a la prevención de riesgos laborales en muchas empresas, que obviamente está repercutiendo en la salud y seguridad de los trabajadores y trabajadoras. No hay ninguna duda de que la actu...
Article
Full-text available
Desde outubro de 2012, o sistema elétrico brasileiro enfrenta problemas com o baixo nível dos reservatórios das hidrelétricas. Este cenário pode levar a racionamento de energia, com reflexos sobre a qualidade de vida da população e crescimento econômico. A Zona da Mata de Minas Gerais, formada por 142 municípios, possui um número significativo de p...
Patent
Full-text available
Patent No. or CCP: ES 2510990 A1; Application No.: P 201330569 (9); Filing date: 19-04-2013; International Patent Classification: C01B 21/082 (2006.01), C08F 226/02 (2006.01). Title (in Spanish): 'Proceso de producción de nitruro de carbono polimérico en nanohojas'.
Conference Paper
Full-text available
Resumen Desde octubre de 2012, el sistema eléctrico brasileño se enfrenta a problemas con el bajo nivel de los embalses hidroeléctricos. Este escenario puede llevar al racionamiento de energía con reflejos en la calidad de vida de la población y en el crecimiento económico. La Zona da Mata, que consiste en 142 municipios, es una de las mesorregione...
Article
Full-text available
The synthesis and characterization of composites of oligomeric chitosan with propolis extract which allow the incorporation of a third component (silver nanoparticles) are reported, together with their application in aqueous or hydroalcoholic solutions with a view to the formation of adhesive substances or nanofilms for the protection of vineyards...
Poster
Full-text available
Desde octubre de 2012 el sistema eléctrico Brasileño enfrenta problemas con el nivel bajo de los embalses hidroeléctricos. Según los expertos este escenario puede conducir al racionamiento de energía. La energía es fundamental para cualquier actividad económica ocurriendo una relación entre el aumento del consumo de energía y el desarrollo económic...
Conference Paper
Full-text available
El residuo más importante en las industrias enológicas son los sarmientos obtenidos en la poda en seco de las cepas. Este tipo de residuos pueden albergar hongos fitopatógenos de la madera que posteriormente pueden ser una fuente de inóculo en la propagación de enfermedades si son abandonados en la propia viña. El compostaje en compostadores cerrad...
Article
Full-text available
The transition from a prevalent turbostratic arrangement with low planar interactions (2D) to an array of polymeric carbon nitride nanosheets with stronger interplanar interactions (3D), occurring for samples treated above 650ºC, was detected by terahertz-time domain spectroscopy (THz-TDS). The simulated 3D material made of stacks of shifted quasi...
Article
Full-text available
The impregnation of a raw sisal fiber in a saturated solution of calcium hydroxide generated a fiber coated by a remarkable quantity of calcium carbonate. This composite preserves the original morphology of sisal fibers. However, some detachments of the inorganic coating are observed at microscopic level; additionally, some fiber components have be...
Poster
Full-text available
La región de Zona da Mata es el mayor centro de producción de pollos de engorde en el estado de Minas Gerais, Brasil. La actividad contribuye de forma destacada en la economía de 34 municipios. La actividad permite la inserción de aproximadamente 600 agricultores, con un 95% clasificados como de pequeños agricultores. Las granjas se encuentran alre...
Article
Full-text available
Serum steroid profiles were investigated in order to evaluate the potential use of circulating sex steroid levels as a tool for sex identification in brown trout. Changes in the serum concentrations of testosterone (T), progesterone (P), 17-β-estradiol (E2), and cortisol (F) in wild and farmed mature female and male brown trout, Salmo trutta L., we...
Conference Paper
Full-text available
Polymeric carbon nitride materials, synthesized from melamine cyanurate, have been studied using time-domain terahertz spectroscopy. The attenuation coefficient of the terahertz signal in the sample is found to provide an excellent signature of the organization properties of the material consisting on curled nanosheets.
Conference Paper
Full-text available
This study evaluates the retention and release capacity of a fungicide (dithianon) by the natural clay halloysite. The halloysite is being a very important subject of study because of its high adsorption / desorption of organic and inorganic chemicals. In this case, halloysite was used to optimize fungicide treatments in Golden-apple fruit trees in...
Conference Paper
Full-text available
In this study, lignocellulosic residues obtained from Macaúba Palm (Acrocomia aculeata) –i.e. pulp, peel, almond and endocarp- and from the shell of Stone Pine (Pinus pinea) nuts have been used for the production of second-generation liquid biofuels, primary and/or secondary bio-products with high added value (namely 5-hydroxymethylfurfural (5-HMF)...
Conference Paper
Full-text available
Alrededor del 95% de las granjas de gallinas ponedores son explotados de forma intensiva en jaulas, generando una gran cantidad de subproductos animales no destinados al consumo humano (SANDACH). El almacenamiento y eliminación de estos subproductos debe correr a cargo del ganadero, produciendo unos elevados coste añadidos y posibles problemas de b...
Patent
Secadero de biomasa de algas y proceso de secado. Comprende un soporte giratorio (6) por cuyo interior circula una biomasa de algas húmedas que fluye a través de unas boquillas de salida que proyectan tales algas húmedas sobre una placa de intercambio (5) caliente que integra una base inclinada cuyo borde inferior circunferencial desemboca en una...
Patent
Full-text available
Patent No. or CCP: ES 2388091 A1; Application No.: P 201130329 (X); Filing date: 10-03-2011. International Patent Clasification: C01F 17/00 ( 2006.01); C01F 1/00 ( 2006.01); H01L 51/50 ( 2006.01); H05B 33/14 ( 2006.01). Title (in Spanish): 'Complejos ternarios octacoordinados de Erbio(III) o Iterbio(III) ópticamente activos y método de obtención'...
Article
Full-text available
Se presenta un modelo basado en Redes Neuronales Artificiales (RNA) para las variables ambientales relativas al proceso de curado de Tabaco. Una RNA de ajuste se empleó para estimar y predecir la temperatura y la humedad relativa en el interior del secadero de tabaco: la estimación consiste en calcular el valor de estas variables en diferentes loca...
Patent
Full-text available
Patente No. or CCP: ES 2381231 A1; Application No.: P 201031560 (X); Filing date: 26-10-2010. International Patent Classification: C25B 1/02 (2006.01). Title (in Spanish): 'Procedimiento para la producción de hidrógeno mediante electrolisis de una solución acuosa de productos orgánicos'. INTERNATIONAL PATENT Pub. No.: WO/2012/056071 International...
Article
Full-text available
Polymeric carbon nitride was synthesized by polycondensation in a nitrogen flux using melamine cyanurate as a reagent and sulfuric acid as a catalyst. The product was polymeric-graphitic carbon nitride based on heptazine units. The carbon nitride was composed of nanosheet flakes. This synthesis method seems to be a suitable pathway toward carbon ni...
Article
Full-text available
This paper presents a system based on an Artificial Neural Network (ANN) for estimating and predicting environmental variables related to tobacco drying processes. This system has been validated with temperature and relative humidity data obtained from a real tobacco dryer with a Wireless Sensor Network (WSN). A fitting ANN was used to estimate tem...
Article
Full-text available
In this work, a Wireless Sensor Network (WSN) based monitoring system for the tobacco drying process is proposed and tested. Energetic, electric and physic variables were considered in order to propose a model for this process, and a set of visualization and calculation tools were developed in order to analyse these data. Finally a mathematical est...
Conference Paper
Full-text available
In this study native cellulose and lignocellulosic waste (pecan walnut shell and carnauba palm leaves), were used for 5-hydroxymethylfurfural (HMF) and furfural production. The heat treatment was conducted in a microwave digester at different temperatures (100°C, 120°C, 130°C, 150°C and 170°C) for 2 minutes. In order to promote the dissolution of c...
Article
Greenhouse climate models are a powerful tool which allows the simulation of inside environmental conditions as a function of external conditions, construction and environmental control equipments characteristics. They also permit to evaluate the energy consumption necessary to obtain the predefined conditions. A theoretical study of the greenhouse...