An improved algorithm for optimal load shedding in power systems

A blackout is usually the result of load increasing beyond the transmission capacity of the power system. A collapsing system enters a contingency state before the blackout. This contingency state is characterized by a decline in the bus voltage magnitudes. To avoid blackouts, power systems may start shedding load when a contingency state occurs called under voltage load shedding (UVLS). The success of a UVLS scheme in arresting the contingency state depends on shedding the optimum amount of load at the optimum time and location. This paper proposes a hybrid algorithm based on genetic algorithms (GA) and particle swarm optimization (PSO). The proposed algorithm can be used to find the optimal amount of load shed for systems under stress (overloaded) in smart grids. The proposed algorithm uses the fast voltage stability index (FVSI) to determine the weak buses in the system and then calculates the optimal amount of load shed to recover a collapsing system. The performance analysis shows that the proposed algorithm can improve the voltage profile by 0.022 per units with up to 75% less load shedding and a convergence time that is 53% faster than GA

An Assessment of the UK’s Trade with Developing Countries under the Generalised System of Preferences

The European Union (EU) Generalised System of Preferences (GSP Scheme) grants preferential treatment to 88 eligible countries. There are, however, concerns that the restrictive features (such as Rules of Origin, Low Preference Margin and Low Coverage) of the existing scheme indicate gravitation towards commercial trade agenda to which efficiency imperatives appear subordinated. Whether these concerns are genuine is an empirical question whose answer largely determines whether, after Brexit, the UK continues with the existing specifics of the EU scheme or develops a more inclusive UK-specific GSP framework. This study quantitatively examines the efficiency of the EU GSP as it relates to UK beneficiaries from 2014 to 2017. We draw on the descriptive efficiency estimation (The utilisation Rate, Potential Coverage Rate, and the Utility Rate) using import data across 88 beneficiary countries and agricultural products of the Harmonised System Code Chapter 1 to 24. Asides the Rules of Origin that, generally, harm the uptake of GSP, low preference margin is found to cause low utilisation rates in a non-linear manner. Essentially, a more robust option (such that allows “global Cumulation” or broader product coverage) could, substantially, lower the existing barriers to trade and upsurge the efficiency of the GSP scheme

A comparison of the effects of physical and chemical mutagens in sesame (Sesamum indicum L.)

Three sesame genotypes (Rama, SI 1666 and IC 21706) were treated with physical (γ-rays: 200 Gy, 400 Gy or 600 Gy) or chemical (ethyl methane sulphonate, EMS: 0.5%, 1.0%, 1.5% or 2.0%) mutagens and their mutagenic effectiveness and efficiency were estimated in the M 2 generation. The M 3 generation was used to identify the most effective mutagen and dose for induction of mutations. The average effectiveness of EMS was much higher than γ-rays. The lowest dose of γ-rays (200 Gy) and the lowest concentration of EMS (0.5%) showed the highest mutagenic efficiency in all genotypes. Analysis of the M 3 generation data based on parameters such as the variance ratio and the difference in residual variances derived from the model of Montalván and Ando indicated that 0.5% concentration of EMS was the most effective treatment for inducing mutations

A Normative Basis for EU External Relations? Protecting Internal Values Beyond the Single Market

This chapter analyses the EU’s obligation to uphold and promote its values and interests in its external polies, in particular as regards some of the values generally underpinning the EU’s internal market, and the rules and principles concerning services of general interest in particular. The first part of the chapter offers a mapping exercise of the relevant Treaty provisions—seeking to establish connections and ways of reading them so that they may “inform” each other. The second part puts them in the context of the debate about Normative Power Europe (NPE) —a much used, but not undisputed international relations concept coined to express the nature of the EU’s external policies and projection. The third inquires further into the “normative” nature and effect of the EU’s constitutional values and objectives. It will be argued that the Treaty normative basis for the EU’s external relations is meaningful and is to be taken seriously

Ultra‐Low Molecular Weight Photoswitchable Hydrogelators

Two photoswitchable arylazopyrozoles form hydrogels at a concentration of 1.2 % (w/v). With a molecular weight of 258.28 g mol−1, these are the lowest known molecular weight hydrogelators that respond reversibly to light. Photoswitching of the E- to the Z-form by exposure to 365 nm light results in a macroscopic gel→sol transition; nearly an order of magnitude reduction in the measured elastic and loss moduli. In the case of the meta-arylazopyrozole, cryogenic transmission electron microscopy suggests that the 29±7 nm wide sheets in the E-gel state narrow to 13±2 nm upon photoswitching to the predominantly Z-solution state. Photoswitching for meta-arylazopyrozole is reversible through cycles of 365 nm and 520 nm excitation with little fatigue. The release of a rhodamine B dye encapsulated in gels formed by the arylazopyrozoles is accelerated more than 20-fold upon photoswitching with 365 nm light, demonstrating these materials are suitable for light-controlled cargo release