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Purpose: The purpose of this study is to explore the influence of perceived organizational support on dimensions of a learning organization among employees of small- and medium-sized enterprises (SMEs) of Nowshahr in Iran. Design/methodology/approach: This paper used an empirical research design by the questionnaire survey method to test the research hypotheses. Statistical population of this research included employees of SMEs of Nowshahr in Iran. A random sample of 950 employees was asked to respond to questionnaires from which 336 were valid. Structural equation modeling was used to explore the influence of perceived organizational support on dimensions of a learning organization. Findings: The findings showed that perceived organizational support had a strong effect on the learning organization. In addition, perceived organizational support had effect on continuous learning, dialogue and inquiry, team learning, embedded system, empowerment, system connection and strategic leadership. In general, all hypotheses are statistically supported. Originality/value: This research may be one of the first papers exploring the influence of perceived organizational support on dimensions of the learning organization and offers a foundation for future organizational research.

This paper presents an AC Optimal Power flow (AC-OPF) problem of a power system, considering wind energy. Wind energy is an environmental-friendly energy source to produce electrical power and it includes less operating costs compared with other sources of electrical power production. Wind generators also affect the operation cost of a power system as well as transmission losses, based on generators locations and speed of wind. In addition, wind speed is a parameter with uncertainty and considering this uncertainty is an important issue in operation of wind generators in the AC-OPF problem. The proposed AC-OPF formulation includes the integer variables in addition to continuous variables and studies the effects of wind energy, transformer tap settings, and shunt capacitors on fuel cost, transmission losses as well as up and down spinning reserves. To solve the AC-OPF model, an Improved Particle Swarm Optimization (IPSO) is presented. The IPSO algorithm in this work includes velocity mirror effect that causes improvement in the quality of the results. The proposed method is applied on modified IEEE 30 bus test system, and obtained results approve the validity and effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

This paper presents a simulation of the dynamic voltage stability in power system. In application of modern power system, dynamic assessment of voltage stability is known as basic concept. In order to study dynamic voltage stability in a power system, different dynamic boundaries are defined such as, Hopf bifurcation (HB) boundary. HB point is an oscillatory boundary in power system. For recognition of the bifurcations, it is unavoidable to study the eigenvalues of power system. In spite of this, determination of these eigenvalues needs to dynamic Jacobian matrix of power system and modal analysis that is very time consuming and complex in large systems. Also, different industrial loads (static and dynamic) e.g. induction motors can effect on dynamic voltage stability boundaries. In this paper, we proposed a solution method based on analyzing the eigenvalues of reduced Jacobian matrix and time domain simulation for assessment of dynamic voltage stability. In addition, effects of industrial electrical loads on the small disturbance voltage stability are evaluated by the proposed method. To show the effectiveness of the proposed solution method, it is tested on IEEE 14 bus and New England test systems. [ABSTRACT FROM AUTHOR]

Development and application of high-speed underwater vehicle is the motivation for many researchers to consider super-captivating flows. Frictional drag decreases and vehicle's velocity increases due to cavity generation. The objective of the present research is to find the coefficients of a relation to estimate cavity length around a submersible vehicle equipped with a wedged-shaped cavitator-which has important practical applications. For this purpose, the super cavitation phenomena has been simulated numerically around three bodies with different geometry. In the first stage, to validate the results of numerical simulation of present work a well-established experimental result of a cylindrical body with hemispheric cap is used for comparison. This comparison is used for parameters effecting numerical method, turbulence flow model and mass transfer model. As this comparison is confirmed, the simulation is continued in the second stage for super cavitation phenomena initiation around a wedged-shaped cavitator with three angles of 15 and 30 and 45 degrees. Inthe third stage, the super cavitation flow is analyzed around a submersible body equipped with a wedged-shaped cavitator. The cavity length and related coefficients are obtained for three cases using different cavitation numbers. The developed equation is similar for all cases with different coefficients. The averaged Navier-Stokes equations are solved in transient case using finite volume method. [ABSTRACT FROM AUTHOR]

In the present work, models that predict contact angle of a droplet with a solid surface are considered and compared. Two phases were assumed to be Newtonian, incompressible and immiscible fluids. OpenFOAM software is applied to simulate the two phases interface by using Color function VOF (CF-VOF) method. Different models for contact angle of a droplet as Tanner and Yokoi models are implemented in the OpenFOAM. In addition, the dynamics and statics contact angle models were used for comparison with recent models in order to choose the best one. The outcome of study shows that, the static contact angle model is simple to understand, and could be the best model to predict the droplet behavior in a wide range of different conditions. The fluid viscosity effect was also considered in different models of the present study. It was concluded that the fluid viscosity affects the type of pattern of droplet impact and as viscosity of fluid increases more energy is needed to uplift the droplet again from the surface. Kelvin-Helmholtz instability [K-H) was also simulated and explained in detail, which initiates on the interface of two fluids due to velocity differences of droplet and the surrounding air. [ABSTRACT FROM AUTHOR]

In this paper, two-phase air-water flow was investigated experimentally and simulated numerically using VOF method. The tests are conducted in Multiphase Flow Lab. of Tarbiat Modares University. In order to evaluate the rib effect on flow regimes, experimental investigation was conducted with ribs of different width and pitch where assembled on front and back side walls (side walls) of the duct during different test runs. The rib width and pitch were held constant during each test. The experimental work considered for different regimes of wavy, plug and slug which generated in the ducts with and without rib applying various phase velocities. The effects of using ribs on regime boundaries are presented in the flow diagrams and discussed in details. Compared to the smooth duct, the ribbed duct affects the different regime boundary positions noticeabily. The results showed that in the duct with small sizes ribs, the first slug initiates at longer time and distance in compare to the duct equipped with bigger size ribs. The results show that for normal operational flow velocities, the ribbed duct decreases the slug area on flow diagram map in compare to smooth duct. However, ribs facilitate the slug regime initiation for phase velocities in accordance with slug generation, which is not benefit of operational condition. [ABSTRACT FROM AUTHOR]

Experimental investigation conducted on Taylor bubble characteristics in a large bend including three consecutive inclinations. For this purposes, flow maps were obtained for the bend and horizontal section of upstream of the bend to define the area of this regime and mechanism of Taylor bubble formation. The effect of superficial gas-liquid velocities and the duct slope were studied on average velocity, length and frequency of bubbles. The results show, the bubble velocity and length increase as gas superficial velocity increases and the duct slope decreases. However, liquid velocity increase has decreasing effect on this characteristics. Bubble frequency is independent of slope change and reduces as gas superficial velocity increase. However, bubble frequency reduces at first and then increase as liquid superficial velocity increases. Regarding the safety regulation for industry, the minimum of the bubble frequency should be generated for the required liquid mass flow rate. Meanwhile, for the gas velocity, some optimization is required between frequency reductions with Taylor bubble velocity increase in addition to bubble length reduction. Regarding the background of the present field with shortage of results on Taylor bubbles frequency, some correlations based on the superficial Reynolds number of phases were presented for each inclination. [ABSTRACT FROM AUTHOR]

Experimental investigation of two-phase air-water flow was conducted at consecutive inclinations of a large bend (with three equal slopes in respect to each other) and including the horizontal sections of the inlet and outlet of the bend. The results show that the elongated bubble regime flows without any effect of duct inclination change and consistent for all three zones of horizontal sections of before and after the bend and the bend itself. It was also noticed, as the duct inclination decreases along the route, vortex misty flow transmits to misty annular flow at higher gas flow rates. The annular flow regime was noticed only at the first slop of the bend. Slug flow was observed at the horizontal sections upstream and downstream of the bend. The slug flow at the upstream generated by the interfacial instabilities but at the downstream formed by Taylor bubbles. Slug flow area in the flow diagram increases as liquid flow rate increase at both horizontal sections. In addition, the void fraction change rate with phases mass flow rate was considered at the duct inlet. [ABSTRACT FROM AUTHOR]

We present a combined trust region–line search structured algorithm for solving constrained nonlinear least-squares problems. The approach is based on adaptive structured scheme due to Mahdavi-Amiri and Bartels of the exact penalty method of Coleman and Conn for nonlinearly constrained optimization problems. The structured adaptation also makes use of the ideas of Nocedal and Overton for handling quasi-Newton updates of projected Hessians. For robustness, we propose a new penalty parameter updating strategy and a specific line search strategy within the trust region, taking account of the least-squares objective and special structured considerations for the approximate projected least-squares Hessians. Our added usage of a second-order correction step in the global phase, combined trust region–line search strategy, and, of course, the new adaptive penalty parameter updating strategy helps in speeding up the global iterations and reaching the asymptotic phase confidently. We discuss the details of our implementation and provide comparative results of the testing of our programs and three nonlinear programing codes from KNITRO on test problems (both small and large residual) from Hock and Schittkowski, Lukšan and Vlček, Biegler et al. and some randomly generated ones due to Bartels and Mahdavi-Amiri. The numerical results obtained by our approach showed a clear local two-step superlinear convergence rate, and as compared to the results obtained by Mahdavi-Amiri and Bartels, the best methods tested in the collection of Hock and Schittkowski, three methods in KNITRO, a recent nonlinear least-squares method of Bidabadi and Mahdavi-Amiri and two algorithms provided byfminconin MATLAB, would indeed confirm the practical significance of our adaptive penalty update scheme, combined trust region–line search strategy, and special structured considerations for the approximate projected least-squares Hessians. [ABSTRACT FROM AUTHOR]

SUMMARY This paper presents a comprehensive formulation for the security constrained optimal power flow (SCOPF) problem considering valve loading effect, multiple fuel option, and prohibited operating zones of units as well as alternating current network modeling and contingency constraints. Also, the SCOPF formulation includes the integer variables, such as discrete transformer tap settings, in addition to continuous variables, such as generation of units. Thus, the suggested SCOPF model is a mixed integer, nonlinear, non-convex, and non-smooth optimization problem. To solve this problem, a new solution method composed of Benders decomposition and special ordered sets is presented. The proposed formulation decomposes the problem into a master problem and a sub-problem. The master problem relaxes the nonlinear constraints of the model using a convex linear outer approximation based on the concept of special ordered sets, whereas the sub-problem contains the nonlinear and non-convex SCOPF formulation with fixed integer and binary variables. To show the effectiveness of the proposed solution method, it is tested on the well-known test systems and compared with several other recently published solution methods. These comparisons confirm the validity of the developed approach. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Purpose – The purpose of this study is to explore the influence of perceived organizational support on dimensions of a learning organization among employees of small- and medium-sized enterprises (SMEs) of Nowshahr in Iran. Design/methodology/approach – This paper used an empirical research design by the questionnaire survey method to test the research hypotheses. Statistical population of this research included employees of SMEs of Nowshahr in Iran. A random sample of 950 employees was asked to respond to questionnaires from which 336 were valid. Structural equation modeling was used to explore the influence of perceived organizational support on dimensions of a learning organization. Findings – The findings showed that perceived organizational support had a strong effect on the learning organization. In addition, perceived organizational support had effect on continuous learning, dialogue and inquiry, team learning, embedded system, empowerment, system connection and strategic leadership. In general, all hypotheses are statistically supported. Originality/value – This research may be one of the first papers exploring the influence of perceived organizational support on dimensions of the learning organization and offers a foundation for future organizational research. [ABSTRACT FROM AUTHOR]

Intrusion detection systems (IDSs) have an important effect on system defense and security. Recently, most IDS methods have used transformed features, selected features, or original features. Both feature transformation and feature selection have their advantages. Neighborhood component analysis feature transformation and genetic feature selection (NCAGAFS) is proposed in this research. NCAGAFS is based on soft computing and data mining and uses the advantages of both transformation and selection. This method transforms features via neighborhood component analysis and chooses the best features with a classifier based on a genetic feature selection method. This novel approach is verified using the KDD Cup99 dataset, demonstrating higher performances than other well-known methods under various classifiers have demonstrated. [ABSTRACT FROM AUTHOR]

Objective: To compare the effects of normal saline and 0.05 betadine on bacterial cultures obtained from eye conjunctiva before and after irrigation during cataract surgery. Methodology: It was a Randomized Control Trial (RCT) in patients with cataract. Culture samples were obtained from the inferior fornix prior to periocular prep and after preparation. Subsequently, inside the eyes and fornices were irrigated with 10 cc normal saline or 4 cc 5% betadine for 3 minutes. Once the data were fed into SPSS software, they were analyzed using χ², Fisher's and McNemar's tests. Results: We obtained 89 positive culture samples (52.4%) before prep (including 38 samples in the normal saline group and 51 samples in the betadine group), 12 positive culture samples (7.1%) after prep, and 8 positive culture samples (4.7%) at the end of surgery. There was no significant relationship between the two groups; however, irrigation was found to be effective in reducing positive cultures in both groups (p<0.001). Conclusion: Using 5% betadine for periocular prep and normal saline for conjunctival irrigation is as effective as using betadine for prep and irrigation in terms of reducing positive cultures after cataract surgery. [ABSTRACT FROM AUTHOR]