Modelación Física de un Invernadero para el Desarrollo de un Sistema de Control Climático

The physical model of a greenhouse is a very important tool for the development of a climate control system. This work presents the analysis and simulation of a model proposed by A. Slim (1993) for a greenhouse. The climate model is formulated with the help of energy balance processes such as conduction, convection, radiation, and vaporization. The analysis of this model allows us to explain the complex interactions of internal climatic variables and how they are influenced by the outside weather. Also, the elements of instrumentation and control necessary for calibration and validation of these models are presented.El modelo físico del clima de un invernadero es una herramienta de suma importancia para el desarrollo de un sistema de control climático en invernaderos. Este trabajo presenta el análisis y simulación del modelo climático de un invernadero propuesto por A. Slim (1993). El modelo está formulado con base en los procesos de transferencia de energía, tales como: conducción, convección, radiación y vaporización. El análisis de este modelo nos permite explicar las complejas interacciones entre las variables climáticas internas, y cómo éstas son influidas por el clima exterior; de tal forma que la información obtenida pueda ser introducida al sistema de control. Así mismo, se presentan los elementos de instrumentación y control necesarios para la calibración y validación del modelo

Development of a remote sensing and control system for greenhouse applications

Real-time monitoring provides reliable, timely information of crop and soil status, important in taking decisions for crop production improvement. This work presents a real-time monitoring and control system for climatological variables in greenhouse. The system has wireless communication capabilities, which allow it to cover extensive surfaces in real-time, without extra resources. The system implementation is based on the micro controllers “PIC18F4550” and “DSPIC 30F5011”, user interface was programmed under LINUX. The proposed system performance was compared with commercial Data Loggers, readings present a linear adjustment with R2=0.9656

Development of a remote sensing and control system for greenhouse applications

Real-time monitoring provides reliable, timely information of crop and soil status, important in taking decisions for crop production improvement. This work presents a real-time monitoring and control system for climatological variables in greenhouse. The system has wireless communication capabilities, which allow it to cover extensive surfaces in real-time, without extra resources. The system implementation is based on the micro controllers “PIC18F4550” and “DSPIC 30F5011”, user interface was programmed under LINUX. The proposed system performance was compared with commercial Data Loggers, readings present a linear adjustment with R2=0.9656

Hacia una gestión alternativa: elementos estructurantes, aproximaciones a la ciudad de Medellín y sus contextos territoriales

En la introducción se formulan los elementos conceptuales orientadores del proceso investigativo; la planeación y la participación, la planeación y la territorialidad, y la percepción de la territorialidad. El capitulo uno presenta los desarrollos del tema relativo a la planeación y el territorio en la ciudad de Medellín y el Área Metropolitana. Este capitulo contiene: El reconocimiento a la problemática; los enfoques y concepciones; sus elementos relacionantes; y la dimensión territorial para la planeación, la participación y el control. capitulo dos hace referencia a los usos, percepciones y significaciones del territorio. Partiendo de las consideraciones metodológicas del trabajo desarrollado, se aborda la problemática del territorio y la territorialidad y del crecimiento territorial urbano en Medellín. El capitulo tres inicia con algunas consideraciones metodológicas y luego desarrolla una serie de aproximaciones a la coyuntura en la ciudad de Medellín, enfatizando en el crecimiento, el presupuesto de la ciudad y la coyuntura. El capitulo cuatro contiene las conclusiones del proceso investigativo organizado según corresponda a los capítulos anteriormente mencionados. Este capítulo de conclusiones termina con la necesidad de formular una estrategia pedagógica de formación y capacitación de recursos humanos para la autogestión del hábitat urbano, particularmente en la ciudad de Medellín y el Área Metropolitana

Índice de contraste morfológico basado en el análisis de los contornos y el fondo de la imagen

Resumen. En este artículo se presenta un índice para cuantificar el contraste que se percibe en una imagen. El índice está basado en la ley de Weber y toma en consideración una estimación del fondo de la imagen mediante la erosión de la apertura por reconstrucción. El desempeño de la propuesta se ilustra con un conjunto de imágenes procesadas por un mapeo de contraste y se compara con dos medidas de contraste dadas en la literatura

β-Carotene Production under Greenhouse Conditions

β-carotene is a secondary metabolite that is a hydrocarbon carotene predominantly located in lower concentrations in PS II functioning as a helper to harvest light pigment during photosynthesis and to dissipate excess energy before damage occurs. As other carotenes, β-carotene is uniquely synthesized in plants, algae, fungi and bacteria. βcarotene is the main diet precursor of pro-vitamin A. Additionally, β-carotene serves as an essential nutrient and is in high demand in the market as a natural food colouring agent, as an additive to cosmetics and also as a health food. Several approaches have been carried out in order to increase β-carotene production in algae, bacteria, fungi and plants using biotechnological and engineering focuses. In the case of plants, such species as the tomato have important β-carotene contents, which are theoretically amenable to management using approaches such as fertilization, growth conditions and mild stress. On the other hand, greenhouse structures can protect crops from wind and rain, and can also protect from insects when fitted with insect exclusion screens. β-carotene production could potentially be improved and enhanced in greenhouse conditions in plants as well as in algae, based on the exclusion of the structure, and the possibility of controlling aspects such as climate, fertilization and stress management, among others. Production of βcarotene (and other secondary metabolites) from several organisms in greenhouse conditions should be an interesting future approach, visualizing the greenhouse as a “factory” in frontier technologies such as biotechnology and mechatronics in order to optimize this production

A New Adaptive Self-Tuning Fourier Coefficients Algorithm for Periodic Torque Ripple Minimization in Permanent Magnet Synchronous Motors (PMSM)

A New Adaptive Self-Tuning Fourier Coefficients Algorithm for Periodic Torque Ripple Minimization in Permanent Magnet Synchronous Motors (PMSM) Torque ripple occurs in Permanent Magnet Synchronous Motors (PMSMs) due to the non-sinusoidal flux density distribution around the air-gap and variable magnetic reluctance of the air-gap due to the stator slots distribution. These torque ripples change periodically with rotor position and are apparent as speed variations, which degrade the PMSM drive performance, particularly at low speeds, because of low inertial filtering. In this paper, a new self-tuning algorithm is developed for determining the Fourier Series Controller coefficients with the aim of reducing the torque ripple in a PMSM, thus allowing for a smoother operation. This algorithm adjusts the controller parameters based on the component’s harmonic distortion in time domain of the compensation signal. Experimental evaluation is performed on a DSP-controlled PMSM evaluation platform. Test results obtained validate the effectiveness of the proposed self-tuning algorithm, with the Fourier series expansion scheme, in reducing the torque ripple