Fuzzy Inference System for VOLT/VAR control in distribution substations in isolated power systems

This paper presents a fuzzy inference system for voltage/reactive power control in distribution substations. The purpose is go forward to automation distribution and its implementation in isolated power systems where control capabilities are limited and it is common using the same applications as in continental power systems. This means that lot of functionalities do not apply and computational burden generates high response times. A fuzzy controller, with logic guidelines embedded based upon heuristic rules resulting from operators at dispatch control center past experience, has been designed. Working as an on-line tool, it has been tested under real conditions and it has managed the operation during a whole day in a distribution substation. Within the limits of control capabilities of the system, the controller maintained successfully an acceptable voltage profile, power factor values over 0,98 and it has ostensibly improved the performance given by an optimal power flow based automation system

Observational constraints to boxy/peanut bulge formation time

Boxy/peanut bulges are considered to be part of the same stellar structure as bars and both could be linked through the buckling instability. The Milky Way is our closest example. The goal of this letter is determining if the mass assembly of the different components leaves an imprint in their stellar populations allowing to estimate the time of bar formation and its evolution. To this aim we use integral field spectroscopy to derive the stellar age distributions, SADs, along the bar and disc of NGC 6032. The analysis shows clearly different SADs for the different bar areas. There is an underlying old (>=12 Gyr) stellar population for the whole galaxy. The bulge shows star formation happening at all times. The inner bar structure shows stars of ages older than 6 Gyrs with a deficit of younger populations. The outer bar region presents a SAD similar to that of the disc. To interpret our results, we use a generic numerical simulation of a barred galaxy. Thus, we constrain, for the first time, the epoch of bar formation, the buckling instability period and the posterior growth from disc material. We establish that the bar of NGC 6032 is old, formed around 10 Gyr ago while the buckling phase possibly happened around 8 Gyr ago. All these results point towards bars being long-lasting even in the presence of gas.Comment: Accepted for publication in MNRAS Letter

Job satisfaction and work–family policies through work-family enrichment

Purpose: The purpose of this paper is to analyze the effect of a bundle of work–family policies on employee’s job satisfaction and (affective) organizational commitment, by using work–family enrichment and conflict as explanatory. Design/methodology/approach: Empirical study is conducted with a sample of 322 employees from 30 Spanish firms that have been granted with the “Flexible Firm Award” or have been certified as “Family Responsible Firms.” Structural equation modeling is used to test hypotheses. Findings: The results show that the higher the use of work–family policies the more positive effects on work–family enrichment and conflict, and that job satisfaction is positively related to (effective) organizational commitment. Research limitations/implications: This is a cross-sectional study which may limit the establishment of causal relationships. Practical implications: Work–family policies may constitute a relevant management tool to balance work and family life by making employees more interested in their jobs, enhancing their well-being and reducing the conflicts between work and family domains. The positive role of work–family enrichment contributes to enhance employees’ job satisfaction and, at the same time, to increase their organizational commitment. Managers should pay attention at how work–family policies are justified because they may influence differently on their outcomes on satisfaction and commitment. Originality/value: There are two main original contributions of the paper. First, the authors study the joint effect of work–family policies on different dimensions of enrichment and conflict. Second, the authors analyze the relationship between different dimensions of enrichment and conflict on job satisfaction and organizational commitment