CONSTRUCCIÓN DE UN SISTEMA DE ADQUISICIÓN DE TEMPERATURA DE SUELO Y NIVEL DE MANTO FREÁTICO PARA APLICACIONES EN BOMBAS DE CALOR DE FUENTES TERRESTRES (CONSTRUCTION OF A SYSTEM FOR THE ACQUISITION OF SOIL TEMPERATURE AND GROUND FLOOR LEVEL FOR APPLICATIONS IN HEAT PUMPS FROM GROUND SOURCES)

Resumen Las bombas de calor de fuente terrestre son sistemas renovables y amigables con el medio ambiente que utilizan la energía subterránea superficial para lograr la calefacción y refrigeración de espacios con el fin de brindar comodidad térmica. En el presente trabajo se presenta la implementación de un sistema de adquisición de datos de nivel freático y temperatura del subsuelo para aplicaciones en bombas de calor de fuentes terrestres. Se han hecho investigaciones sobre el suelo para conocer sus características térmicas en diferentes ciudades de México, sin embargo, no se han hecho estas investigaciones en la zona de Ciudad del Carmen Campeche. Se utilizaron sondas de temperatura Dallas ds18b20 y un sensor de distancia ultrasónico HC-SR04. Para la transmisión y recepción inalámbrica se utilizó el transceptor NRF24L01. El sistema de lectura de sensores-transmisión y el sistema de recepción-adquisición de datos fue implementado con el microcontrolador Atmega328p en una tarjeta de desarrollo de prototipos Arduino uno. El sistema de lectura y transmisión de datos fue del tipo autónomo alimentado por un panel solar de 12 voltios y 450 mah de tipo mono cristalino. Se utilizó una batería de plomo-ácido de 12 voltios. La adquisición de datos del receptor a una computadora personal fue a través del puerto USB, utilizando el software Processing, el cual almacena los datos cada hora en una hoja de cálculo. Los datos fueron recibidos y almacenados adecuadamente, de igual forma el sistema de energía fotovoltaica funcionó ininterrumpidamente. Palabras Clave: Arduino, sensor de nivel de agua, Sensores de temperatura. Abstract Ground Source Heat Pumps are environmentally friendly, renewable systems that use surface underground energy to achieve space heating and cooling for thermal comfort. In this work, the implementation of a temperature and water table data acquisition system for applications in Ground Source Heat Pump is presented. Investigations have been made on the soil to know its thermal characteristics in different cities of Mexico; however these investigations have not been done in the Ciudad del Carmen Campeche area. Dallas ds18b20 temperature probes and an HC-SR04 ultrasonic distance sensor were used. For wireless transmission and reception, the NRF24L01 transceiver was used. The sensor reading-transmission system and the data reception-acquisition system were implemented with the Atmega328p microcontroller on an Arduino Uno prototype development board. The data transmission and reading system was of the autonomous type, powered by a 12 V, 450 mah mono-crystalline type solar cell. A 12 volts lead-acid battery was used. The acquisition of data from the receiver to the pc was through the USB port, using the software processing, which stores the data every hour in a spreadsheet. The acquisition of data from the receiver to a personal computer was through the usb port, using processing software, which stores the data every hour in a spreadsheet. The data was received and stored properly, in the same way the photovoltaic energy system worked without interruption. Keywords: Arduino, CNC, GRBL, lineal interpolation, Self-leveling

Maternal Characteristics Determine Stunting in Children of Less than Five Years of Age Results from a National Probabilistic Survey

Background Maternal nutrition and some variables are the main determining factors of birthweight and delayed intrauterine growth of children. Objective To explore the association between the mothers’ biological and sociodemographic characteristics, and the anthropometry status in children under five years of age. Design The population consisted of a sub-sample of 1,047 mother-and-child selected pairs from the probabilistic National Nutrition Survey, carried out in Mexico. Mother-and-child pairs included mothers aged 12 to 49 years, with children under five years of age. Data on sociodemographic characteristics, obstetric history, 24-hour recall dietary intake, and the women and children's anthropometry were collected. The association between maternal characteristics and children's anthropometry status was assessed using multiple logistic regression models. Result Nearly 16.7% of the children 2y). The height/age of the children was severely affected by maternal height and birth order. In addition, the interaction between socioeconomic level and maternal schooling had a marginal effect (p = 0.09) in the ≤2y group. On the other hand, whether the family received social services and the interaction between maternal height and a dichotomy urbanism variable were significant (p = 0.05) and (p 2y group. Conclusion Some biological and socioeconomic characteristics among mothers have a negative effect on their children's attained size, especially in the period between 2 and 5 years of age