In this paper development and validation of a simple linear model for estimating radio refractivity from meteorological parameters are presented. Twelve months radiosonde meteorological data for Cross River state which was obtained from Nigerian Meteorological Agency (NIMET) was used to determine the radio refractivity (N). The correlation between the refractivity and the atmospheric temperature (T), atmospheric pressure (P) and relative humidity (U) were examined for twelve months dataset. The correlation values showed that temperature (T) and the product of P, H and T had the highest correlation with respect to N in all the twelve months. Based on the correlation values among the parameters examined, a simple linear model was developed to estimate the radio refractivity. In all the twelve months dataset, the mathematical model gave worst case absolute percentage error of about 3.3%. Two sample meteorological dataset from published articles were also used to validate the model. The model gave a maximum absolute percentage error of 2.46 % for the first test meteorological dataset while it gave a maximum absolute percentage error of 1.25 % for the second test meteorological dataset. In all, the linear model presented in this paper will make it easier to compute the radio refractivity from available meteorological data. The results from the validation dataset showed that the model can also be applied to every other region other than the case study area where the data for the model development were obtained.

In this work, we propose a Genetic Algorithm (GA) for effectively scheduling ambulances aftermath of a disaster. Given the limited number and capacity of ambulances, we aim to minimize the number of ambulance tours and the average time to take all injured people to a hospital. Both of these goals require that the total tour length of all routes should be minimized as well. This problem can be considered as an extension of the well-known Capacitated Vehicle Routing Problem (CVRP). We developed a Genetic Algorithm (GA) and tested using some of the CVRP benchmark files. For the possible number of injures at each location, we define three different scenarios. The proposed GA aims to minimize the tour lengths of the ambulances while respecting all real life constraints given in these scenarios. In order to evaluate the proposed GA, we also developed a rival method based on the Nearest Neighbor (NN) heuristic. The results of extensive simulation test NN heuristic.

Friction stir spot welding is the energy efficiency, environment friendly and relatively new low energy technology adopted from Friction stir welding (FSW) with many potential applications in joining light alloys in the automotive industry. In 2001, Friction stir spot welding (FSSW) was developed in the automotive industry to substitute resistance spot welding for aluminum sheets. FSSW process has some advantages such as ease of joining materials, low distortion, excellent mechanical properties, low power consumption, low cost and more economical than RSW. The strength of welds is critical when applying FSSW to load bearing components. This strength is affected mainly by process parameters and tool geometry. Tool geometry, such as shoulder diameter and shape, pin shape, length, diameter and feature is a key parameter to affect heat generation and material flow. The objective of this paper is to review open literature sources to assess the current state-of-the-art developments in Friction Stir Spot Welding, effect of various welding variables like tool rotation, transverse speed, dwell time, tool tilt, plunge depth and tool design on mechanical properties in the welding of aluminium alloys or various dissimilar alloys. However the Literature review indicates that there is need to identify the effect of different process parameters on Mechanical properties in FSSW.

This writing describes a 5.8 GHz microwave system that is suitable for use in undergraduate laboratories or as a demonstration tool. The system is constructed mainly from off-the-shelf components and can be configured by anyone possessing a basic knowledge of electronics. The types of demonstrations that the system can be used for is vast and cannot be addressed in a single writing. Therefore, the authors outline one exercise and results that explores wave interference based on propagation and phase delays. The phase delays are produced via spatial and feed line delays.

This paper uses the mathematical software Maple for the auxiliary tool to study the partial differential problem of four types of multivariable functions.We can obtain the infinite series forms of any order partial derivatives of these four types of multivariable functions by using differentiation term by term theorem, and hence greatly reduce the difficulty of calculating their higher order partial derivative values.On the other hand, we propose some examples to do calculation practically.The research methods adopted in this study involved finding solutions through manual calculations and verifying these solutions by using Maple.This type of research method not only allows the discovery of calculation errors, but also helps modify the original directions of thinking from manual and Maple calculations.For this reason, Maple provides insights and guidance regarding problem-solving methods.

Osteoporosis or 'porous bones' is the major cause of bone fracture in elderly post-menopausal women.As such, predicting fracture occurrence can significantly reduce the associated morbidity and reduce health-care expenditures.Examining local micro-structure of trabecular bone is becoming increasingly important for investigating bone fracture behavior.Conventional voxel based measures of bone architecture cannot provide morphology information regarding the fractures occurring at individual trabeculae.In this paper, the Delaunay triangulation, a computational geometry technique is used for assessing the effect of trabeculae structure on local micro-fracture, from sequential 2D images of the cross section of a hamster femur surface undergone a multistage loading until fracture occurrence.The most significant structural parameters to characterizethe strength of cancellous bone and the change in morphology of individual trabeculae during the fracture process are investigated.The results from different regions were compared to describe the possible architectural factors affecting the local micro-damages.

On the basis of information on impact of ultrasonic and hydrodynamic cavitation on water in various engineering and agrochemical applications parameters of the frequencies favoring to an intensification of growth of some grades of tomatoes, shanks of decorative roses and saplings of a pine ordinary are defined.The example of the engineering application of operated hydrodynamic cavitation on the basis of the independent generator of warmth for heating is presented.This example was patented and successfully used further for water structuring in some agrochemical applications.Results of researches of influence of acoustic radiations in the range of frequencies of 20 Hz -50 kHz and operated hydrodynamic cavitation on growth of some types of plants and data on influence of the specified private range on some physical and chemical properties of irrigation water are presented.It is shown that for a productive drop irrigation of skilled plants the range of ultrasonic radiation in a range close to 20 kHz which leads to increase of concentration of microcells of the metals dissolved in irrigation water is most effective and also influences favorable change of pH of irrigation water.Experimentally an established fact of increase of productivity of tomatoes for 15 % at rather short-term period of watering by the structured water and considerable effect of increase in growth of root system at saplings of decorative roses.Also established an experimentally fact of decrease in an electric conductivity of irrigation water after hydrodynamic cavitational impact on 18-23 %, along with favorable change of pH of water.Some factors influencing an intensification of growth of saplings and development of root system with considerable decrease in pathogenic micro flora are analyzed and revealed.