Chemical and Structural Analysis of Rocks Using X-ray Fluorescence and X-ray Diffraction Techniques

Rock examinations for mining and commercial use are a vital process to save money and time. A variety of methods and approaches have been used to analyze rocks and among them, X-ray fluorescence (XRF), and X-ray diffraction (XRD) techniques proved to be an accurate method. This research was conducted to evaluate the utility and reliability of XRF and XRD to analyze the major and trace elements of rocks as well as their crystalline structures. Results showed that XRF and XRD techniques are fast and reliable, nondestructive and non-invasive analytical tools for mineral analysis, particularly for rocks. For this purpose, the analysis of 28 samples of rocks, which collected from three different places of Kurdistan region-Iraq, is reported. These places are Haybat Sultan (HS) region in Koya city as well as TaqTaq (TA) and Garmuk (GT) district nearby Koya city. Throughout this analysis, 34 major and trace elements were detected in the rocks collected from HS region, whereas forty major and trace elements were detected in the rocks collected from TA district and GT district. In addition, it was found that the structures of these rocks were crystalline in nature. This was proved through the value of diffracted angle and it was found that the majority of these rocks are oxides. The external view (the appearance) of all collected rocks was also discussed and it was found that each rock consists of a variety of minerals which will be the reason that each rock has a specific color

Extracting Double Diode Model Parameters Based on Cross Entropy Optimization Algorithm

A Cross Entropy (CE) optimization technique is suggested in this study in order to extract the optimal parameters of solar cell model. The solar cell model namely Double diode model, is used in this paper in the purpose to verify the proposed method. The seven unknown parameters of double diode model are: the photo-generated current, the diffusion current, saturation current, the series resistance, the shunt resistance, the diffusion ideality factor and recombination diode ideality factor. These parameters were used to determine the corresponding maximum power point (MPP) from the illuminated current–voltage (I–V) characteristic. The metaheuristic algorithms have created a center of attention due to the non-linearity of the solar cell models and the incapability of traditional optimization methods to precisely extract the parameters. Different cases and studies have been done to identify the unknown parameters of the solar cell double model. The efficiency of CE algorithm is investigated by comparing this method with various and different other techniques. This comparison is done using statistical indicators and analysis such as: mean absolute bias error, root mean square error and coefficient of determination. The results show that CE is a very efficient technique to identify the electrical parameters of the PV solar cells and modules

3-Dimensional Nonlinear Finite Element Analysis of both Thermal and Mechanical Response of Friction Stir Welded 2024-T3 Aluminum Plates

This paper attempt to predict numerically both the temperature distribution during friction stir welding process of 2024-T3 aluminium plates and the resulting thermal residual stress by sequentially coupling the thermal histories into the mechanical model assuming elastic-perfectly plastic metal behaviour in accordance with the classical metal plasticity theory. The commercial code ANSYS 14 is used in Thermomechanical modelling of friction stir welding of aluminium 2024-T3.  Heat input from the tool shoulder and the tool pin are considered in the finite element analysis model. A moving heat source with a heat distribution simulating the heat generated from the friction between the tool shoulder and the work piece is used in the heat transfer analysis The longitudinal stress components are found to be the highest tensile stress components and correspond to the temperature profiles within the heat affected zone of the weld. The through-thickness (normal) stresses are found to be negligible compared with the longitudinal and transverse stress components. To facilitate simulation runs of the proposed model an APDL (ANSYS Parametric Design Language) code is developed to extract the thermal history and the subsequent thermal stresses. The effects of various heat transfer conditions at the bottom surface of the workpiece, thermal contact conductances at the work-piece and the backing plate interface on the thermal profile in the weld material are taken into considerations. The results of the simulation are compared to other published experimental results and the agreement was good. Keywords: Friction stir welding, Finite element, Three dimensional modeling, Thermal stresses

Prevalence of Intestinal Parasites under Fingernails of Primary School Children in Zakho, Kurdistan Region

In this study, 103 fingernails samples were collected (31 female and 72 male) from primary school children aged between 6 to12 years, which lived in Zakho city during the period from March to November, 2015. Each fingernail sample was immersed in normal saline, and subsequently centrifuged for 5 minutes at 2500 rpm. The supernatant was discarded; a few drops of the sediment of each sample were placed on the center of a clean glass slide with a drop of iodine or eosin, and then examined microscopically. The results revealed a total rate of 25.24% of infection with parasites. The recorded parasites with their rates included: eggs of Enterobius vermicularis, Hymenolepis nana, Ascaris lumbricoides and Trichuris trichaura (7.76, 5.82, 2.91 and 0.97 %, respectively) and cysts of Entamoeba histolytica and Giardia lamblia (4.85 and 2.91 %). According to age, the highest percentage of infection occurred in 9 years old children. Regarding the gender, males showed a higher rate of infection than females (17.47 % versus 7.76%, respectively). These results clarify the role of fingernails in the transmission of parasitic infections, which requires continuous cleaning and cutting