Pareto distribution is used in many economic, financial and social applications. This distribution is used for the study of income and wealth and the study of settlement in cities and villages and the study of the sizes of oil wells as well as in the field of communication through the speed of downloading files from the Internet according to their sizes. This distribution is used in mechanical engineering as one of the distributions of models of failure, stress and durability. Given the practical importance of this distribution on the one hand, and the scarcity of sources and statistical research that deal with it, this research touched on some statistical characteristics such as derivation of its mathematical function , probability density function, cumulative distribution function, methods of estimating parameters, and the difficulties that researchers may face in dealing with these phenomena. The parameters were estimated in a number of methods, including the Maximum Likelihood (MLE), Ordinary Least Squares (OLS), Moment method (MOM), Relative Least squares (RELS) and Ridge regression (RR). In addition an algorithm has been proposed to improve the estimation parameters for this distribution. MSE was used to determine the best of these methods. Conclusions were presented in the light of this and appropriate proposals were decided upon.
Background: Among individuals who have a stenotic aortic valve, a precise assessment of aortic valve area is essential for clinical judgment. So far, no studies have been conducted to investigate and assess the role of the three dimensional echo-cardiography in the assessment of the valve stenosis. This study aims to compare and assess the precision of the measurement of the stenosis area of the aortic valve by 2D versus 3D echo-cardiography.
This paper attempted to study the effect of cutting parameters (spindle speed and feed rate) on delamination phenomena during the drilling glass-polyester composites. Drilling process was done by CNC machine with 10 mm diameter of high-speed steel (HSS) drill bit. Taguchi technique with L16 orthogonal layout was used to analyze the effective parameters on delamination factor. The optimal experiment was no. 13 with spindle speed 1273 rpm and feed 0.05 mm/rev with minimum delamination factor 1.28. &
... Show MoreA liquid-solid chromatography of Bovine Serum Albumin (BSA) on (diethylaminoethyl-cellulose) DEAE-cellulose adsorbent is worked experimentally, to study the effect of changing the influent concentration of (0.125, 0.25, 0.5, and 1 mg/ml) at constant volumetric flow rate Q=1ml/min. And the effect of changing the volumetric flow rate (1, 3, 5, and 10 ml/min) at constant influent concentration of Co=0.125mg/ml. By using a glass column of (1.5cm) I.D and (50cm) length, packed with adsorbent of DEAE-cellulose of height (7cm). The influent is introduced in to the column using peristaltic pump and the effluent concentration is investigated using UV-spectrophotometer at 30oC and 280nm wavelength. A spread (steeper) break-through curve is gained
... Show MoreDoppler broadening technique is suggested to monitor the development of tumours. It depends on the sensitivity of positronium (Ps) annihilation parameters to the sub- microstructural changes in biological tissues. This technique uses high resolution HpGe detector to measure the lineshape parameters (S and W) in normal mice's mammary tissues and adenocarcinoma mammary tissues as a function of tumour growth. The results demonstrate that the central parameter (S) decreases and the wing parameter (W) increases as the tumour grow. It is found that the S parameter changes considerably with the distribution of voids which are affected by the tumour development. Therefore the present technique can successfully be employed to monitor the developm
... Show MoreThe Indian costus plasma properties are investigated including electron temperature (Te), "electron density (ne)", "plasma frequency (fp)", " Debye sphere length", and amount of Debye(Nd), using the spectrum of optical emission technique. There are several energies used, with ranging from 300 to 600 mJ. The Boltzmann Plot is used to calculate the temperature; where as Stark's Line Broadening is used to calculate the electron density. The Indian costus was spectroscopically examined in the air with the laser at 10 cm away from the target and the optical fiber at 0.5 cm away. The results were obtained for an electron temperature range of (1.8-2.2) electron volts (ev) and a wavelength range of (300-600) nm. The XRF analysis reveals th
... Show MoreDC glow discharges were generated between a thin cylindrical anode and a flat cathode, streamers are thought to propagate by photo-ionization; the parameters of photo-ionization depend on the He: CO ratio. Therefore we study streamers in He ( 90%, 80% and 70% ) with (10%, 20% and 30%) CO respectively. The streamer diameter is essentially the change by increase for similar voltage and pressure in all He-CO mixtures.
The parameters of resistance spot welding (RSW) performed on low strength commercial aluminum sheets are investigated experimentally, the performance requirements and weldability issues were driven the choice of a specific aluminum alloy that was AA1050. RSW aluminum alloys has a major problem of inconsistent quality from weld to weld comparing with welding steel
alloys sheet, due to the higher thermal conductivity, higher thermal expansion, narrow plastic temperature range, and lower electrical resistivity. Much effort has been devoted to the study of describing the relation between the parameters of the process (welding current, welding time, and electrode force) and weld strength. Shear-tensile strength tests were performed to ind
Abstract This research scrutinizes the impact of external magnetic field strength variations on plasma jet parameters to enhance its performance and flexibility. Plasma jets are widely used for their high thermal and kinetic energy in both medical and industrial fields. The study employs optical emission spectroscopy to measure electron temperature, electron density, and plasma frequency in a plasma jet subjected to varying magnetic field strengths (25, 50, 100, 150, and 250 mT). The results indicate that a stronger magnetic field results in higher electron temperature (1.485 to 1.991 eV), electron density (5.405 × 1017 to 7.095 × 1017), and plasma frequency 7.382 × 1012 to 8.253 × 1012 Hz. As well as the research investigates the influ
... Show MoreIn this paper, construction microwaves induced plasma jet(MIPJ) system. This system was used to produce a non-thermal plasma jet at atmospheric pressure, at standard frequency of 2.45 GHz and microwave power of 800 W. The working gas Argon (Ar) was supplied to flow through the torch with adjustable flow rate by using flow meter, to diagnose microwave plasma optical emission spectroscopy(OES) was used to measure the important plasma parameters such as electron temperature (Te), residence time (Rt), plasma frequency (?pe), collisional skin depth (?), plasma conductivity (?dc), Debye length(?D). Also, the density of the plasma electron is calculated with the use of Stark broadened profiles