Software for the geometric characterisation of insect-proof screens

Martínez, Antonio Jesús Álvarez; Oliva, Rocío M.; Valera, D.L.

doi:10.1016/j.compag.2012.01.001

Cited by 25 publications

(25 citation statements)

References 17 publications

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“…The methodology used to characterise the geometry of the insect-proof screens was developed at the University of Almería [36,37,38]. For each insect-proof screen, three samples of approximately 2.04 cm 2 were analysed.…”

Section: Methodsmentioning

confidence: 99%

Wind Tunnel Analysis of the Airflow through Insect-Proof Screens and Comparison of Their Effect When Installed in a Mediterranean Greenhouse

López

Molina-Aiz

Valera

et al. 2016

Sensors

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The present work studies the effect of three insect-proof screens with different geometrical and aerodynamic characteristics on the air velocity and temperature inside a Mediterranean multi-span greenhouse with three roof vents and without crops, divided into two independent sectors. First, the insect-proof screens were characterised geometrically by analysing digital images and testing in a low velocity wind tunnel. The wind tunnel tests gave screen discharge coefficient values of Cd,φ of 0.207 for screen 1 (10 × 20 threads·cm−2; porosity φ = 35.0%), 0.151 for screen 2 (13 × 30 threads·cm−2; φ = 26.3%) and 0.325 for screen 3 (10 × 20 threads·cm−2; porosity φ = 36.0%), at an air velocity of 0.25 m·s−1. Secondly, when screens were installed in the greenhouse, we observed a statistical proportionality between the discharge coefficient at the openings and the air velocity ui measured in the centre of the greenhouse, ui = 0.856 Cd + 0.062 (R2 = 0.68 and p-value = 0.012). The inside-outside temperature difference ΔTio diminishes when the inside velocity increases following the statistically significant relationship ΔTio = (−135.85 + 57.88/ui)0.5 (R2 = 0.85 and p-value = 0.0011). Different thread diameters and tension affects the screen thickness, and means that similar porosities may well be associated with very different aerodynamic characteristics. Screens must be characterised by a theoretical function Cd,φ = [(2eμ/Kpρ)·(1/us) + (2eY/Kp0.5)]−0.5 that relates the discharge coefficient of the screen Cd,φ with the air velocity us. This relationship depends on the three parameters that define the aerodynamic behaviour of porous medium: permeability Kp, inertial factor Y and screen thickness e (and on air temperature that determine its density ρ and viscosity μ). However, for a determined temperature of air, the pressure drop-velocity relationship can be characterised only with two parameters: ΔP = aus2 + bus.

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Section: Methodsmentioning

confidence: 99%

Wind Tunnel Analysis of the Airflow through Insect-Proof Screens and Comparison of Their Effect When Installed in a Mediterranean Greenhouse

López

Molina-Aiz

Valera

et al. 2016

Sensors

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“…In agriculture there are various software that help producers in decision making, in the determination of the rice grain quality (CAPPELLI et al, 2015), the interference of climate change on production (LARDY et al, 2015) information management system precision agriculture (NIKKILÄ et al, 2010) also the characterization of the types of insects (ÁLVAREZ et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Software to Assess Beef Cattle Body Mass Through the Fuzzy Body Mass Index

et al. 2016

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The Body Mass Index (BMI) can be used by farmers to help determine the time of evaluation of the body mass gain of the animal. However, the calculation of this index does not reveal immediately whether the animal is ready for slaughter or if it needs special care fattening. The aim of this study was to develop a software using the Fuzzy Logic to compare the bovine body mass among themselves and identify the groups for slaughter and those that requires more intensive feeding, using "mass" and "height" variables, and the output Fuzzy BMI. For the development of the software, it was used a fuzzy system with applications in a herd of 147 Nellore cows, located in a city of Santa Rita do Pardo city -Mato Grosso do Sul (MS) state, in Brazil, and a database generated by Matlab software.KEYWORDS: computer system, IMC, Mamdani and profits. SOFTWARE PARA A AVALIAÇÃO DE GANHO CORPORAL DE REBANHO NELORE PELO ÍNDICE DE MASSA CORPORAL FUZZYRESUMO: O Índice de Massa Corporal (IMC) pode ser utilizado por pecuaristas para auxiliar na determinação do momento da avaliação de ganho corporal do animal. No entanto, o cálculo desse índice não revela imediatamente se o animal está apto ao abate ou se necessita de cuidados especiais para recuperação. O objetivo deste trabalho foi desenvolver um software utilizando a lógica fuzzy para a comparação da massa corporal de bovinos entre si e identificação dos grupos para abate, e dos que necessitam de alimentação mais intensa, utilizando-se das variáveis "massa" e "altura", e a saída IMCFuzzy. Para a elaboração do software, utilizou-se de um sistema fuzzy com aplicações em um rebanho de 147 vacas nelore, localizado em Santa Rita do Pardo-MS, e um banco de dados gerado pelo software Matlab.

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“…Se seleccionó una metodología de análisis geométrico ampliamente utilizada en diversos trabajos de reportados sobre caracterización geométricas de mallas anti-insectos (Cabrera et al, 2006;Álvarez et al, 2012). Mediante la toma during 2013.…”

Section: Caracterización Geométrica De Las Mallasunclassified

“…Esta puede ser observada mediante un microscopio como una superficie plana. Una de las propiedades geométricas más importantes de estos materiales es su porosidad α (m 2 m -2 ) definida como la superficie ocupada por los orificios con respecto a la superficie total de la malla (Álvarez et al, 2012;Cabrera et al, 2006;Valera et al, 2006) y puede ser calculada por la ecuación (8) para una malla con mismo tipo de hilo en ambas direcciones de tejido.…”

Section: )unclassified

Características aerodinámicas de mallas anti-insectos usadas en ventanas de invernaderos en México

Vega

Arias

Cruz

2017

Remexca

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ResumenSe analizaron mediante pruebas de microscopía y en túnel de viento, las características geométricas, porosidad y la caída de presión, respectivamente de siete diferentes mallas comúnmente usadas como barreras físicas en ventanas de invernaderos mexicanos para determinar su efecto sobre la tasa de ventilación, la permeabilidad y el factor inercial. Las mallas se analizaron en la Universidad Autónoma Chapingo en mayo de 2013 y fueron: anti-trips (M1), anti-trips bicolor (M2), anti-áfidos (M3), anti-áfidos bicolor (M4), cenital (M5), rompevientos verde-negro (M6) y anti-áfidos blanca (M7), cuyas porosidades fueron 0. 36, 0.35, 0.47, 0.45, 0.54, 0.29 y 0.43 respectivamente. La geometría de las mallas se realizó midiendo las áreas de los poros con un microscopio óptico, para determinar las porosidades y calcular el descenso de la tasa de ventilación. Posteriormente, las características aerodinámicas más importantes; es decir, permeabilidad y factor inercial, se determinaron usando un túnel de viento para medir la relación entre la caída de presión causada por cada malla y la velocidad del flujo de aire. Los resultados mostraron que la malla cenital (M5) presenta la menor resistencia al flujo de aire con 21% de descenso en la tasa de ventilación, mientras que la malla rompevientos verde-negra (M6) fue de 50%. Los invernaderos en México normalmente usan la malla del tipo anti-áfidos con porosidad entre 0.43 y 0.47 para las ventanas laterales y cenitales. AbstractThey were analyzed by tests microscopy and wind tunnel, geometric characteristics, porosity and pressure drop, respectively seven different meshes commonly used as physical barriers windowing Mexican greenhouses to determine its effect on the ventilation rate, permeability and the inertial factor. The meshes were analyzed in the Chapingo in May 2013 were: anti-thrips (M1), antithrips bicolor (M2), anti-aphid (M3), anti-aphid bicolor (M4), zenithal (M5), green-black windbreaker (M6) and anti-aphid white (M7), whose porosities were 0.36, 0.35, 0.47, 0.45, 0.54, 0.29 and 0.43 respectively. The geometry of the meshes is performed by measuring the areas of the pores with an optical microscope to determine the porosities and calculate the decrease in ventilation rate. Subsequently, the most important aerodynamic characteristics; i. e. inertial factor and permeability were determined using a wind tunnel to measure the relationship between the pressure drop caused by each mesh and the speed of the airflow. The results showed that the zenithal mesh (M5) has the least resistance to air flow with 21% decrease in ventilation rate, while the greenblack windbreaker mesh (M6) was 50%. Greenhouses in Mexico typically use anti-aphid mesh with porosity between 0.43 and 0.47 for the side windows and zenithal type.

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Software for the geometric characterisation of insect-proof screens

Cited by 25 publications

References 17 publications

Wind Tunnel Analysis of the Airflow through Insect-Proof Screens and Comparison of Their Effect When Installed in a Mediterranean Greenhouse

Wind Tunnel Analysis of the Airflow through Insect-Proof Screens and Comparison of Their Effect When Installed in a Mediterranean Greenhouse

Software to Assess Beef Cattle Body Mass Through the Fuzzy Body Mass Index

Características aerodinámicas de mallas anti-insectos usadas en ventanas de invernaderos en México

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