30 research outputs found
In-vitro evaluation of certain Egyptian traditional medicinal plants against Propionibacterium acnes
GIZA 11 AND GIZA 12; TWO NEW FLAX DUAL PURPOSE TYPE VARIETIES
Sixteen flax genotypes {13 promising lines and 3 check varieties viz., Giza 8 (oil type), Sakha 1 (dual purpose type) and Sakha 3 (fiber type)} were evaluated for straw, seed, oil yields and their related traits under twelve different environments; four locations (Sakha, Etay El-Baroud, Ismailia and Giza Exp. Stations through three successive seasons (2011/12, 2012/13 and 2013/14). These materials were evaluated in a randomized complete blocks design with three replications at the twelve above-mentioned environments. The analysis of variance revealed highly significant differences among genotypes (G), environments (E) and G x E interaction for all studied traits except straw weight per plant, indicating a wide range of variation among genotypes, environments and these genotypes exhibited differential response to environmental conditions. The significant variance due to residual for all characters except both straw weight per plant and oil yield per fad indicated that genotypes differed with respect to their stability suggesting that prediction would be difficult, which means that mean performance alone would not be appropriate. Interaction component of variance (σ2ge) was less than the genotypic variance (σ2g) for all characters, indicating that genotypes differ in their genetic potential for these traits. This was reflected in high heritability and low discrepancy between phenotypic (PCV) and genotypic (GCV) coefficients of variability values for these traits indicating the possibility of using each of long fiber percentage, plant height and technical stem length as selection indices for improving straw weight per plant, as well as, using 1000-seed weight and capsules number per plant as selection indices for improving seed weight per plant. Yield stability (YSi) statistic indicated that S.541-C/3 and S.541-D/10 gave high mean performance and stability for straw, fiber, seed and oil yields per fad in addition to oil percentage, capsules number per plant and 1000-seed weight. Therefore, the two genotypes well be released under the name Giza 11 and Giza 12, respectively. These newly released varieties are of dual purpose type for straw, fiber, seed and oil yield. They may replace the low yielding cultivars Giza 8, Sakha 1 and Sakha 3
Deposition of sub-micron particles onto AGR fuel elements
(AGR - Advanced Gas-cooled Nuclear Reactor)Available from British Library Document Supply Centre- DSC:DX86169 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo
New Recursive Formulas for Eigenvalue Sensitivity Analysis
Eigenvalue sensitivity analysis represents a key discipline in many engineering system applications where the dynamic behavior of such systems is closely related to the eigenvalues of the system (state) matrix. Currently available eigenvalue sensitivity evaluation methods are based on a general form of the system matrix derivatives with respect to the sensitivity parameter of interest. In many engineering systems, however, the structure of the system matrix is such that its derivatives with respect to practical system parameters constitute special rank-one forms. This paper presents a novel application of a compact matrix exchange formula to the eigenvalue sensitivity problem, which includes rank-one derivative matrices, leading to very fast recursive sensitivity formulas with substantial savings in computation time and memory requirements. With such recursive formulas, the evaluation of higher-order eigenvalue sensitivities is therefore attainable using previously calculated lower-order sensitivities. An illustrative application to power system dynamic stability analysis is presented in which the new eigenvalue sensitivity formulas were successfully used to estimate the effect of parameter changes on the dynamic system modes
An Improved Algorithm for Efficient Computation of Current Distribution in Power Cables
Unequal current distribution inside underground cables in close proximity causes unfavorable induced voltages and losses in their sheaths. Because of the problem complexity, most previous researchers in the field have not modeled the skin and proximity effects with sufficient accuracy. In this paper, a new technique is presented for tackling the eddy current problem of non-magnetic multi-conductor systems. The technique utilizes an efficient impedance matrix formulation, which yields accurate current distribution assessment. Applications to a set of test cable systems are also presented in the paper to demonstrate the usefulness of the proposed technique
Dynamic stability improvement via coordination of static var compensator and power system stabilizer control actions
Power system controllers such as the static var compensators and the power system stabilizers are receiving a wide interest since many technical studies have proven their effects on damping system oscillations and stability enhancement. This paper is mainly concerned with coordinating the control actions of static var compensators and power system stabilizers to achieve improved dynamic performance of the power system using the newly developed concept of 'domains of influence'. Novel sensitivity-based algorithms are presented for the purpose of effectively identifying the domains of influence of various control parameters on critical dynamic system modes. Applications to the Saudi Consolidated Electric Company (SCECO) power system show that significant improvement in power network stability can be achieved via coordinating the control actions of both static var compensator and power system stabilizer instead of using them individually in an uncoordinated manner. © 2001 Elsevier Science B.V
Development, consumption rates and reproductive biology of Orius albidipennis reared on various prey
The predatory bug Orius albidipennis (Reuter) (Hemiptera: Anthocoridae) has tremendous potential as a biological control agent, especially in its native range around the Mediterranean Basin and East Africa. The need to exploit native biological control agents is growing in importance as concerns over the introduction of non-native species continue to increase. However, little is known of the effects of different prey on development and reproduction of O. albidipennis compared with other species of Orius. Therefore, we compared the development, survival, reproductive biology, and prey consumption of O. albidipennis when fed eggs of Ephestia kuehniella Zeller, Tetranychus urticae Koch, and Trialeurodes vaporariorum (Westwood), and larvae of Gynaikothrips ficorum (Marchal), under laboratory of 26 ± 1°C, 60 ± 10% RH and 16L:8D photoperiod. Individuals were reared from the neonate stage until death on one of the four prey types. The type of prey had profound effects on all measured performance traits. The highest survival rate was recorded for nymphs that were fed on E. kuehniella eggs, while the lowest survival rate was observed for those fed on T. vaporariorum eggs. The shortest nymphal period was recorded for nymphs fed on E. kuehniella eggs, while the longest was measured for those fed on T. urticae eggs. During the nymphal period, O. albidipennis consumed significantly more eggs of T. urticae than other prey types, whereas the lowest number of consumed prey were eggs of E. kuehniella. Adult females and males consumed significantly more T. urticae eggs than other types of prey. However, Orius albidipennis females showed the highest fecundity when fed on E. kuehniella eggs, and the lowest when fed on T. vaporariorum eggs. Adult females and males that fed on G. ficorum larvae had significantly longer life spans compared with those fed other prey. Because of their relatively rapid development and high fecundity, O. albidipennis fed E. kuehniella eggs had a significantly higher net reproductive rate (Ro) and intrinsic rate of increase (r m ) than O. albidipennis fed other prey types. Overall, eggs of E. kuehniella were the most suitable diet for nymphs and adults of O. albidipennis. Although less suitable, O. albidipennis could survive and reproduce on the other prey types, which is a favourable attribute in biological control agents. These results on the effect of different prey types on development and reproduction of O. albidipennis will also contribute to the development of mass rearing programs for biological control agents in developing countries, such as Egypt
Probabilistic approach to electrical safety assesment in the development of effective building codes in Saudi Arabia
An important part of developing an effective building code is the adherence to strict
safety codes. Electrical safety and the associated issue of fault current breaker
performance, in particular, are extremely important in this regard since the nature of
electricity consumption in the Kingdom of Saudi Arabia and the improved style of
living have led to a continual increase in the consumption demand which inevitably
resulted in a corresponding increase in the expected fault current levels resulting from
faults taking place randomly in the building.
This paper presents an advanced probabilistic fault current analysis methodology and the
associated computerized algorithm which incorporate an efficient risk-assessment
model in order to simulate, more accurately, the various fault current scenario aspects
in buildings and evaluate the associated electrocution risk. The methodology
presented is believed to assist the electrical building code developers in order to know
and assess the probability of both electrocution hazards and domestic equipment
failure due to excessive fault currents. The approach adopted utilizes the desirable
features of the Monte Carlo simulation method as it provides a simple and reliable way
of treating the statistical distributions associated with complicated electrical building
components. A demonstrative application is also presented in the paper in order to
illustrate the implementation features of the presented approach.Corresponding Author:
Dr. Abdulhameed Alohaly, Electrical Engineering Department, College of Engineering, King Saud University, P.O. Box 800, Riyadh-11421
Riyadh, Saudi Arabia.
Email: [email protected]