Archives-December 

In this paper, low frequency oscillations in power system under the different operating conditions have been solved through conventional power system stabilizer and PID based power system stabilizer. The tuning of the parameters of the PSSs are considered as optimization problem, and the parameters are tuned using genetic search algorithm. Here forth –order linear and non-linear model of the synchronous machine (model 1.1) which includes both the generator main field winding and the damper winding in q-axis is considered for finding out the sensitivity of electromechanical modes of single machine infinite bus system. The effectiveness of automatic voltage controller, and Conventional and PID -power system stabilizer are identified through eigen value analysis and participation factor method. The non-linear simulation results show the effectiveness and capability of two schemes of PSS for power system stability improvement under various disturbances.

This paper analysed the possibility of expansion of Nekede Mechanic-Village gully located in Imo State Nigeria using Geotechnical tests method. The gully site is located on longitude 7o 2’ 6”E and latitude 5o 27’ 46”N. The analysis of the Geotechnical tests showed that Site Areas 3 and 4 are structurally week and susceptible to erosion due to their poor Shear Strength and Bulk Density values – in addition to being Non-Plastic. In contrast, site areas 1 and 2 are relatively stable. Sites 3 and 4 are located close to residential areas thus demanding desperate attention from government agencies before the expanding gully wreaks havoc.

Hamartomas are one of the most common benign tumors of the lung. We report a case of huge pulmonary hamartoma of the left lower lobe in a 33-year-old female patient. The pulmonary hamartoma was solid, measuring 30 x 16.5 x 14.5 cm, closing a cystic and calcium component. It was successfully treated by surgical resection and the final histology was a pulmonary hamartoma with no signs of malignancy. we report a new case of a giant hamartochondroma very little described in the literature

It is well known that a dynamical system is a concept in mathematics where a fixed rule describes how a point in a geometrical space depends on time. A mathematical models is a precise representation of a system's dynamics used to answer questions via analysis and simulation. Mathematica models allow us to reason about a system and make predictions about who a system will behave. Contact geometry is the odd-dimensional analogue of symplectic geometry. It is close to symplectic geometry and like the latter it originated in questions of classical and analytical mechanics. If contact geometry is considered as a symplectic geometry, it has broad applications in mathematical physics, geometrical optics, classical mechanics, analytical mechanics, mechanical systems, thermodynamics, geometric quantization and applied mathematics such as control theory. It is well known fact that one way of solving problems in classical mechanics occur with the help of the Hamilton equations. Hamiltonian method is particularly important because of its utility in formulating quantum mechanics. In this study, Hamilton equations as representive the object motion were found on a contact 5-manifolds. Also, implicit solutions of the differential equations found in this study are solved by Maple computation program.

The current work presents a theoretical study of the solar power plant with parabolic trough solar collector, the power generated from the solar power plant was calculated with using the thermal storage system without using such a system then comparison between the two cases. The calculations of the thermal storage system in terms of the size of the thermal tank and the temperature of the heat transfer fluid inside the thermal tank as well as its mass are implemented. The theoretical study are completed at Baghdad city (Long. of 44.25° East and Latit. of 33.19° North). The results were obtained by simulating the solar power station with parabolic troughs for both cases by using the thermal storage system and without it. During this work, some hypotheses were created to facilitate the solution of the system of equations for such plants. It was assumed that the specific heat of the heat transfer fluid in the tank of heat accumulation system was constant, It was calculated at the outlet temperature solar field for the heat transfer fluid, which was up to 390 °C, in addition to other hypotheses will be identified during the study steps. As a key to solving the issue was initially calculated direct solar radiation for Baghdad city and the result indicates that the frequency distribution of direct solar radiation was not more than 14% of the radiation values which less than 500 W/m2. Thus, the results leads us to the inference that during the months of low temperature in a city such as Baghdad, don't need a large increase in the size of the solar field or keep the solar field as it is and use thermal storage system, be in our case with a small size which is therefore reflected that be a reasonable cost. The power generated from the solar power plant was also calculated for both cases without the use of thermal storage systems and with it, where the capacity of the solar power plant under study with a value of 50 MW, It is noted that the maximum value of the net power was achieved during some months of the year, especially in June, July and August. As for thermal storage, it is clear that the station is work for more than 20 hours during the day in June, July and August. Therefore, the results obtained in this study were compared with the results obtained from the Solar Advisor Model, which was implemented by the National Renewable Energy Laboratory in the United States of America. There was a reasonable consensus in the results, but it does not match exactly because the working conditions of both cases, the geographical position and the situation is completely different weather but remains the general behavior of the two stations is similar.

In the present study, investigation of the chemical quality of water at the Qareh sou catchment has been carried out to evaluate the suitability of water for irrigation purpose. Water quality of the area has been studied based on physico- chemical analysis of six hydrometer stations during 2010. Various parameters, such as pH, EC, chloride, sulfate, bicarbonate, sodium, potassium, calcium and magnesium have been determined to evaluate this purpose. Irrigation water quality on the basis of Doneen’s permeability index, residual sodium carbonate, sodium adsorption ratio, Magnesium adsorption ratio, Kelley’s ratio, Corrosivity Ratio, potential soil salinity and Chadha’s diagram have been computed. Results showed that the water was suitable for irrigation purpose. According to Chadha’s diagram, the type of water is determined as Ca–Mg–HCO3. Also, according to the Wilcox diagram water classified as ‘excellent’ and ‘good’, except for the Siah ab and Naharkhoran stations, but Corrosivity Ratio suggests that the Qareh sou water is not safe for Water Transmission. In shastkola and pol ordgogah stations, the value of MAR is harmfully over 50%.

To supply blood, arties and veins plays the important role in the body similarly, road networks plays a vital role in transportation system. Transportation system has geared up its performance level by constructing expressways, national highways, state highways etc. in consideration of increasing traffic. “Black spot is the place where accidents are historically occurred” This paper emphasis the study of some local city roads (Khadi Machine Chowk-Kondhwa, KMC-Undri and KMC-Katraj) of Pune. From the present traffic accident statistics the identification of accidental black spots is done in present study by using ranking method with the help of severity index.

This quasi-experimental study with pretest-posttest design intended to compare the effect of focus on form versus. focus on forms instruction on grammar achievement among Azari-speaking EFL third-grade high school students at Bostan Abad, East Azerbaijan. Two intact classes were provided by the two different instruction methods, the scores of Forty two students out of them were taken into account. There were twenty four persons in experimental group and twenty one students in control group. To ensure comparability and homogeneity of the participating groups prior to their treatment, participants are given the Nelson test, and to measure the effects of treatment, a grammar test , taken from university entrance exam tests (Konkur) , was administered. The results of Independent-samples t-test indicated that there was a significant difference in scores for experimental group(M=31.47 ,SD=7.55)and control group(M=26.28,SD=8.13 ;t(40)= -2.14 ,p=0.03,two-tailed).The magnitude of the differences in the means(mean difference=-5.19 ,95 CI: -10.08to -0.29)was very large effect(eta squared=0.10).The learners in the focus on form group outperformed the learners in the focus on forms instruction . It is highly recommended that teachers should correct errors in learners’ written or spoken language in ways that help them notice and learn from their errors.

This study was conducted to investigate the factors that contribute towards the turnover intention of teachers of private sector schools of Sargodha division. For this purpose several factors of satisfaction i.e. security, nature of work, working condition, colleagues (integration), principal, students, recognition, social status and promotion are considered because these are the main factors which increase or decrease the turnover intention of teachers. Data was collected through paper and pencil technique from various private schools of Sargodha division. Pearson correlation and zero order correlation were used to test the hypotheses. Only four factors i.e. principal, promotion, pay and working conditions were proved to have a strong negative relationship with turnover intention.

Moringa oleifera (M. oleifera) is renowned for its range of essential nutrients and bioactive compounds. However, the toxicity and potential radiation modifying effects of extracts from its entities are not well characterised. The cytotoxic and radiomodulatory effects of aqueous extracts obtained from seeds, leaves and flowers of M. oleifera were evaluated. Cytotoxicity and radiation modifying effects of extracts were assessed in apparently normal Chinese hamster lung fibroblasts (V79 cells), using the colony forming assay. The free radical scavenging activity of each extract was also assessed, using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay. At relatively low concentrations of 6.25–100 µg/ml, the seed extract showed about 20% cytotoxicity and yielded radiation sensitizing factors ranging from 1.23±0.07 to 2.38±0.76. The leaf extract was non-toxic at concentrations of up-to 50 µg/ml, but produced ~12% cell kill at 100 µg/ml. With the little or no cytotoxity on its own, the leaf extract was radiosensitizing, with radiation modifying factors ranging from 1.30±0.18 to 1.50±0.26. At all tested concentrations, the flower extract was non-toxic, but significantly enhanced cell growth in unirradiated cultures, showing no effect on cellular radiation response. With the exception of the leaf extract which had a maximum of only 9% free radical scavenging capacity, the other extracts showed no potential as radical scavengers. Aqueous extracts of seeds, leaves and flowers of M. oleifera may potentially be clinically useful as cytotoxic agents, radiosensitizers, and wound healing promoters.