Nine existing sunshine based models and three existing temperature based models were evaluated and compared to ascertain the most suitable models for estimating global solar radiation in Maiduguri; the most suitable sunshine based and most suitable temperature based models were also compared. The measured monthly average daily global solar radiation, sunshine hours, maximum and minimum temperature meteorological parameters during the period of thirty one years (1980 – 2010) was utilized and the evaluated models were tested statistically using validation indicators of coefficient of determination, Mean Bias Error, Root Mean Square Error, Mean Percentage Error, t – test, Nash – Sutcliffe Equation and Index of Agreement. The results indicated that the linear exponential sunshine based model and the logarithmic temperature based model were found more accurate for global solar radiation estimation in Maiduguri as compared to other evaluated models. Furthermore, the logarithmic temperature based model was found more accurate for estimating global solar radiation as compared to the linear exponential sunshine based model, and this was testified from the figure showing the comparison between the recommended sunshine based and temperature based models in which the recommended temperature based model depicts the best fitting with the measured global solar radiation data.

Earthquakes are among the hidden forces that threaten human life and the future of civilization. And with the technological progress and studies in space sciences, the Earth did not receive the attention of studies and researches, especially those related to earthquakes. This paper is presents a brief study of the magnetic and physical properties of the elemental compositions of the earth's crust as an attempt to find out the causes of earthquakes. Results of calculations have suggested that compressions and tensions on the earth crust due to the interaction of the earth magnetic field with the magnetic materials in the crust may be one of the main causes of earthquake events.

Compression schemes can be divided into two categories, lossy and lossless, but this paper presents lossless data compression models and the original data can be correctly recovered from the data compressed material. Some mathematical results are assumed; the results of probability tests are assumed and used to evaluate the compression techniques we will discuss. To learn more about math concepts for some of the topics in this article, see [2, 3]. First, we look at several ideas in information theory that provide a standard for the development of lossless data compression schemes are briefly reviewed. We next look at several ways to model data that lead to efficient data compression encryption schemes.

3D printing has emerged as a transformative technology that has revolutionized various industries and unlocked endless possibilities in the world of Research and Development. 3D printing allows the fabrication of three- dimensional parts from computerized designs by utilizing additive manufacturing technologies. Its importance stems from its capacity to expedite prototyping, speed up production, and stimulate innovation in industries including as healthcare, manufacturing and aerospace. The main objective of this study is to analyze the mechanical behavior of 3 dimensional (3D) printed Poly-Lactic Acid (PLA) parts when their infill density and infill geometry are varied. We have taken 3 infill geometries (Grid, Triangle, Gyroid) at 4 different infill densities (40%, 60%, 80%, 100%), these parts are measured for tensile strength and optimal conditions are identified.