This study assesses the effect of some soil physical properties on the thermal diffusivity and soil heat flux over Ayadi in Ondo State, Nigeria. Physical properties of the soil at different depths were determined using laboratory techniques. In-situ measurement of air temperature and surface soil temperature were carried out. The phase lag method was used to determine the thermal diffusivity of the soil, while the subsoil heat flux was determined from values obtained for the thermal diffusivity. The result showed that the subsoil heat flux values during the dry season ranged between 0.58 and 52.84 W/m2, while that of the wet season ranged between -0.77 and 98.50 W/m2. The average thermal diffusivity values at the different depths had values between 0.74 × 10-7 and 238.7 × 10-7 m2/s for the dry season, while the wet season had a range of 1.97 × 10-7 to 238.7 × 10-7 m2/s. Keywords: soil moisture content, air temperature, soil temperature, soil heat flux, thermal diffusivity.

The potential occurrence of certain illnesses can be easily diagnosed through measurements of some health indicators. One of such parameters is the Body Mass Index (BMI). BMI is simply the ratio of mass (kg) of a body to the square of its height (m2). This research presents the design and construction of an automated BMI measurement machine for medical purposes. It consists of three major units: the weighing unit (5 – 200 kg); height-measuring unit (0.02 – 2 m) and the processing unit. The weighing unit is made up of load button cell and load cell amplifier while the height-measuring unit consists of ultrasonic sensor. The analog differential output voltage from load cell is connected to arduino microcontroller via a Programmable Gain Amplifier (PGA) integrated with Analogue-to-Digital Converter (ADC). The two units are connected to an open source arduino uno which computes mass-to-body ratio and sends the output results (mass, height and BMI) to the liquid crystal display (LCD). The weighing system was calibrated against a precision digital weighing system and it gave a correlation of 0.99. The height measurement was also compared with manual height measurement using a tape rule which gave a correlation of 0.97. The developed Instrument is cost effective and has high positive correlation with the standards (weighing scale and tape rule), it is therefore recommended for the measurement of weight, height and BMI. Keywords— load button cell, load cell amplifier, ultrasonic, body mass index, arduino uno

Accurate estimation of refractivity gradient and geoclimatic factor is highly necessary for radio signal propagation in clear air environment to cater for fade margin, essential for a reliable radio link. This is necessary because of the unstable nature of the environment the signal is traversing. These parameters were estimated from the meteorological parameters of surface air and dew temperature, temperature and relative humidity obtained from European Centre for Medium-Range Weather Forecasts (ECMWF) archive during the period of 36 years. Point refractivity gradient at 100 m with refractive conditions were estimated for different locations across Nigeria in tropical region. The results show that the seasonal variation experience across the locations were influenced by the movement of inter tropical discontinuity. Values of geoclimatic factor also varies seasonally and geographically. Moderate association exist between β factor and latitude with correlation coefficient of 0.45 which is statistically significant as p<0.05. However, weak or nonrelationship exist between β, µ, altitude and longitude as indicated by correlation coefficient.

This paper presents the influence of silicon nanoparticles at the interface of heterostructured Cadmium telluride and cadmium sulfide thin films based photovoltaic device with improved electrical parameters leading to tremendous improvement in CdS/CdTe thin f ilm based solar cells performance. The films of CdTe, CdS and Si were electrodeposited using electrodeposition technique to form a heterostructured CdTe/Si/CdS/FTO. The films respective structural properties were also examined using X-ray Diffractometer (XRD) before forming a heterostructured material. The heterostructured CdTe/Si/CdS/FTO and the structure without the inclusion of silicon nanoparticle were examined using electrometer for the extraction of electrical parameters such open circuit voltage (VOC), short circuit current density (JSC), and fill factor (FF). Although a large body of experimental results are available to date on the optoelectronics properties of the materials. However, there is relatively low research studies or works on the electrical properties of the materials. Therefore, we formed heterostructured based photovoltaic device and characterized the structure to determine useful electrical properties. The value obtained for VOC, JSC and FF are 418 mV, 25 mA/cm2 and 0.72 which are indicative of pin holes free semiconductor materials and no leakage path emerging from high-grade materials used in the deposition of heterostructured CdTe/Si/CdS.

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