A simplified analytical approach for optimal planning of distributed generation in electrical distribution networks

DG-integrated distribution system planning is an imperative issue since the installing of distributed generations (DGs) has many effects on the network operation characteristics, which might cause significant impacts on the system performance. One of the most important characteristics that mostly varies because of the installation of DG units is the power losses. The parameters affecting the value of the power losses are number, location, capacity, and power factor of the DG units. In this paper, a new analytical approach is proposed for optimally installing DGs to minimize power loss in distribution networks. Different parameters of DG are considered and evaluated in order to achieve a high loss reduction in the electrical distribution networks. The algorithm of the proposed approach has been implemented using MATLAB software and has been tested and investigated on 12-bus, 33-bus, and 69-bus IEEE distribution test systems. The results show that the proposed approach can provide an accurate solution via simple algorithm without using exhaustive process of power flow computations

Existence of Solutions for a Class of Quasi-Linear Singular Integro-Differential Equations

2000 Mathematics Subject Classification: 45F15, 45G10, 46B38.An existence theorem is proved for a class of quasi-linear singular integro-differential equations with Cauchy kernel

Effect of Rosemary and Sweet Marjoram on three Predacious Mites of the Family Phytoseiidae (Acari: Phytoseiidae)

The direct toxicity of two essential oils, Majorana hortensis, Moench and Rosmarinus officinalis L. to adult females of the predacious mites, Amblyseius zaheri Yousef and El-Borolossy, Amblyseius barkeri (Hughes) and Typhlodromus athiasae Porath and Swirski were tested. Rosemary oil was the most toxic to females of A. barkeri and the least to A. zaheri. In contrast,sweet marjoram oil was relatively toxic to T. athiasae and slightly toxic to A. barkeri. Both essential oils,decreased the food consumption rate at the concentration used for A.barkeri and A. zaheri. Females of A. barkeri and A. zaheri suffered a depression in reproduction when treated with 1% of rosemary oil.Both material used seems to be harmless to T. athiasae at 1%

On the Motion of a Rigid Body in the Presence of a Gyrostatic Momentum

In this paper, the rotational motion ofa rigid body about a fixed point in the Newtonian force field with a gyrostatic momentum l3 about z- axis is considered. The equations of motion and their first integrals are obtained and have been reduced to a quasilinear autonomous system of two degrees offreedom with one first integral. Poincaré’s small parameter method (Malkin, 1959) is applied to investigate the analytical periodic solutions of the equations of motion of the body with one point fixed. rapidly spinning about one of the principal axes of the ellipsoid of inertia. A geometric interpretation of motion is given by using Euler’s angles (Ismail, 1997a) to describe the orientation ofthe body at any instant of time

A Necessary and Sufficient Condition for Solving a Rigid Body Problem

In this paper, the motion of a rigid body about a fixed point under the influence of a Newtonian force field is investigated. The Euler-Poisson equations are used to represent that motion. Three first integrals of these equations are well known. The exact solutions of these equations require, in general, a fourth algebraic first integral. The necessary and sufficient condition for some functions to be a fourth first integral of the governing equations is obtained

Activity Dependent Branching Ratios in Stocks, Solar X-ray Flux, and the Bak-Tang-Wiesenfeld Sandpile Model

We define an activity dependent branching ratio that allows comparison of different time series $X_{t}$. The branching ratio $b_x$ is defined as $b_x= E[\xi_x/x]$. The random variable $\xi_x$ is the value of the next signal given that the previous one is equal to $x$, so $\xi_x=\{X_{t+1}|X_t=x\}$. If $b_x>1$, the process is on average supercritical when the signal is equal to $x$, while if $b_x<1$, it is subcritical. For stock prices we find $b_x=1$ within statistical uncertainty, for all $x$, consistent with an ``efficient market hypothesis''. For stock volumes, solar X-ray flux intensities, and the Bak-Tang-Wiesenfeld (BTW) sandpile model, $b_x$ is supercritical for small values of activity and subcritical for the largest ones, indicating a tendency to return to a typical value. For stock volumes this tendency has an approximate power law behavior. For solar X-ray flux and the BTW model, there is a broad regime of activity where $b_x \simeq 1$, which we interpret as an indicator of critical behavior. This is true despite different underlying probability distributions for $X_t$, and for $\xi_x$. For the BTW model the distribution of $\xi_x$ is Gaussian, for $x$ sufficiently larger than one, and its variance grows linearly with $x$. Hence, the activity in the BTW model obeys a central limit theorem when sampling over past histories. The broad region of activity where $b_x$ is close to one disappears once bulk dissipation is introduced in the BTW model -- supporting our hypothesis that it is an indicator of criticality.Comment: 7 pages, 11 figure