Resilience of modern power distribution networks with active coordination of EVs and smart restoration

Abstract In this modern era of cyber–physical–social systems, there is a need of dynamic coordination strategies for electric vehicles (EVs) to enhance the resilience of modern power distribution networks (MPDNs). This paper proposes a two‐stage EV coordination framework for MPDN smart restoration. The first stage is to introduce a novel proactive EV prepositioning model to optimize planning prior to a rare event, and thereby enhance the MPDN survivability in its immediate aftermath. The second stage involves creating an advanced spatial–temporal EV dispatch model to maximize the number of available EVs for discharging, thereby improving the MPDN recovery after a rare event. The proposed framework also includes an information system to further enhance MPDN resilience by effectively organizing data exchange among intelligent transportation system and smart charging system, and EV users. In addition, a novel bidirectional geographic graph is proposed to optimize travel plans, covering a large penetration of EVs and considering variations in traffic conditions. The effectiveness is assessed on a modified IEEE 123‐node test feeder with real‐world transportation and charging infrastructure. The results demonstrate a significant improvement in MPDN resilience with smart restoration strategies. The validation and sensitivity analyses evidence a significant superiority of the proposed framework

On the diffusion of lattice matched InGaAs/InP microstructures

Copyright (2003) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in F. Bollet et al., J. Appl. Phys. 93, 3881 (2003) and may be found at http://link.aip.org/link/?jap/93/388

A fully integrated autonomous power management system with high power capacity and novel MPPT for thermoelectric energy harvesters in IoT/wearable applications

This paper reports a fully integrated autonomous power management system for thermoelectric energy harvesting with application in batteryless IoT/Wearable devices. The novel maximum power point tracking (MPPT) algorithm does not require open circuit voltage measurement. The proposed system delivers 0.5 mA current with 1 V regulated output based on simulations, which is the highest output current for a fully integrated converter reported in the literature for ultra-low voltage applications, to the best knowledge of the authors. Regulated 1 V output can be achieved for load range >2 k Omega, and input voltage range >140 mV. The circuit has been implemented in UMC-180nm standard CMOS technology and simulated

The GP Tests of Competence assessment: which part best predicts fitness to practise decisions?

BACKGROUND: The General Medical Council (GMC) conducts Tests of Competence (ToC) for doctors referred for Fitness to Practise (FtP) issues. GPs take a single best answer knowledge test, an Objective Structured Clinical Examination (OSCE), and a Simulated Surgery (SimSurg) assessment which is a simulated GP consultation. The aim of this study was to examine the similarities between OSCEs and SimSurg to determine whether each assessment contributed something unique to GP ToCs. METHODS: A mixed methods approach was used. Data were collated on 153 GPs who were required to undertake a ToC as a part of being investigated for FtP issues between February 2010 and October 2016. Using correlation analysis, we examined to what degree performance on the knowledge test, OSCE, and SimSurg related to case examiner recommendations and FtP outcomes, including the unique predictive power of these three assessments. The outcome measures were case examiner recommendations (i) not fit to practise; ii) fit to practise on a limited basis; or iii) fit to practise) as well as FtP outcomes (i) erased/removed from the register; ii) having restrictions/conditions; or iii) be in good standing). For the qualitative component, 45 GP assessors were asked to rate whether they assess the same competencies and which assessment provides better feedback about candidates. RESULTS: There was significant overlap between OSCEs and SimSurg, p < 0.001. SimSurg had additional predictive power in the presence of OSCEs and the knowledge test (p = 0.030) in distinguishing doctors from different FtP categories, while OSCEs did not (p = 0.080). Both the OSCEs (p = 0.004) and SimSurg (p < 0.001) had significant negative correlations with case examiner recommendations when accounting for the effects of the other two assessments. Inductive thematic analysis of the responses to the questionnaire showed that assessors perceived OSCEs to be better suited to target specific knowledge and skills. SimSurg was thought to produce a more global picture as the scenarios more accurately portray a patient consultation. CONCLUSION: While all three assessments are strong predictors of both case examiner recommendations and FtP outcomes, our findings suggest that the efficiency of GP ToCs can be improved by removing some of this overlapping content

Economically and technically feasible treatment for residue-driven leachate of landfills

Sri Lankan government has a policy on land filling along with the implementation of 3R (Reduce, Reuse, Recycle) where landfills are to be used only to dispose residue waste instead of unsorted waste. Sri Lanka, in response to this policy, has planned to have several landfills in the country with a view to managing the residue waste generated following the process of composting.Residue-waste comprise of long term biodegradable waste or/and non-biodegradable waste where the long term biodegradables account for large amount of tannins, cellulose, hemicelluloses. These tannins can accumulate to a level that is toxic to bacterial degradation. Tannin is characterized with high COD, BOD, TOC and turbidity levels in leachate. There has been an issue of only using biological treatment for residue-driven leachate as it may create a situation where biological treatment alone would not be possible to yield the acceptable level of treatment. Hence, it is of utmost importance to eliminate tannin prior to biological treatment.This study was carried out to find the most economical and technically feasible method to treat residue-driven leachate. Chemical treatment encompassing coagulation and flocculation chemical process is used to treat tannin in residue-driven leachate with different combinations of coagulants and flocculants at pH 7. Optimum treatment results were observed with a combination of alum and a polyelectrolyte having removal efficiencies for COD, BOD, TOC, turbidity, and tannin to be in the range of 38-40%, 25-28%, 92%, 85% and 80% respectively. It was also noted that the black color changed to colorless indicating higher levels of tannin removal. Further, the sludge arising from chemical treatment that would be easily managed within the landfill is an added advantage. Thus removal of tannin from residue driven leachate with chemical treatment prior to the biological treatment is highly recommended. As chemically treated residue-driven leachate showed BOD and COD levels higher than the proposed leachate emission levels an aerobical treatment using activated sludge can be carried out with the bio reactor.Keywords: Chemical treatment, Coagulation, Leachate, Residue-wast

Biological Treatment of Leachate Using Sequencing Batch Reactor

In Sri Lanka municipal solid waste is generally disposed in poorly managed open dumpswhich lack liner systems and leachate collection systems. Rain water percolates through thewaste layers to produce leachate which drains in to ground water and finally to nearby waterbodies, degrading the quality of water. Leachate thus has become a major environmentalconcern in municipal waste management and treatment of leachate is a major challenge forthe existing and proposed landfill sites.The study was conducted to assess the feasibility of the usage of the Sequencing BatchReactor in the treatment of the landfill leachate up to the proposed levels in the draft report of“Proposed Sri Lankan standard for landfill leachate to be disposed to the inland waters".Leachate collected from the open dumpsite at Meethotamulla, Western Province, Sri Lankawas used for leachate characterization.SBR was constructed with a 10-liter working volume operated in an 18 hour (h) cycle modeand each cycle consists of 15 h of aerobic, 2 h settle and 0.5 h of fill/decant stages. TheDissolved Oxygen level within the SBR was maintained at 2 mg/l through the aerobic stage.Infeed was diluted with water during the acclimatization period and a leachate to water ratioof 55:45 was maintained. The removal efficiencies for different parameters were; COD(90.5%), BOD (92.6%), TS (92.1%), Conductivity (83.9%), Alkalinity (97.4%), Hardness(82.2%), Mg (80.5%), Fe (94.2%), Zn (63.4%), Cr (31.69%), Pb (99.6%), Sulphate (98.9%),and Phosphorus (71.4%) respectively. In addition Ni and Cd were removed completelyduring a single SBR cycle.Thus the dilution of leachate in the dumpsites using municipal wastewater, groundwater orrainwater was identified as the most cost effective dilution methods. The effluent from theSequencing batch reactor is proposed to be further treated using a constructed wetland beforereleasing to surface water.

Are Green Jobs Sustainable for Sri Lankan Economy?

It is imperative that Sri Lanka grasps the concepts of green jobs to meet the most vital but intricatechallenge of the 21st Century, which is the transformation to a sustainable and a low-carbon economy.Such a transformation or a paradigm shift, which can be gradual or rapid depending on the circumstances,will undoubtedly have a considerable positive effect on the way we produce and/or consume goods andservices. The speed at which this transformation would occur is likely to accelerate in the near future asthere is a trend of global transition from a traditional to a low-carbon economy, in order to attainsustainable economies. Such trends will help create an array of different forms of green jobs across manysectors, and most probably can become a catalyst for further development. The International LabourOrganization (ILO) has defined green jobs as “Jobs created when they help in reducing the negativeenvironmental impacts ultimately leading to environmentally, economically and socially sustainableenterprises and economies”. Green jobs, in general, stand on two pillars: decent work and environmentalsustainability. Thus, green jobs can be defined as decent work that contributes to environmentalsustainability. In a broader sense decent work needs to address the core of international labour standardssuch as freedom of association and effective recognition of the right to collective bargaining, eliminationof all forms of forced or compulsory labour, effective abolition of child labour, elimination ofdiscrimination in respect of employment and occupation, occupational health and safety, etc. whilstaligning to laws applicable to Sri Lanka. Environmental sustainability addresses issues such as effectivelycombating climate change, pollution prevention and control, conservation of eco-systems and biodiversityetc. (ILO, 2007)

Zinc adsorption by lowcost sorbent materials: clay tile, Brick, sawdust and rice husk

It has been found over the past couple of years rapid growth of population, industrialization and urbanization has first and foremost contributed to the severe water pollution in both surface and ground water. The health hazards associated with heavy metals have been on the rise, particularly the chronic diseases. Lack of tertiary treatment of wastewater may have contributed to this emergent problem, adsorption process is considered as the best available water treatment method and activated carbon has proven to be the best sorbent material which can be used in removing wide variety of pollutants. However, usage of this activated carbon becomes restrict due to its high cost and regeneration cost. Therefore, the present study focuses on low-cost sorbent materials: viz., clay tile, brick, sawdust and rice husks. Laboratory-scale experiments were performed with a synthetic Zinc solution. Results revealed that clay tile material has the highest adsorption capacity (47.6 mg/g) and removal efficiency, (98%), while brick (37.0 mg/g, 86%), sawdust (20.4 mg/g, 80%) and rice husks (15.8 mg/g, 64%) have relatively low adsorption capacities and removal efficiencies, respectively. The separation factor of equilibrium (RL) indicates favourable isotherms (0< RL<1) for all tested sorbent materials. Among the studied materials clay tile, brick and rice husks are good adsorbent for Zinc (n>2) while sawdust is a moderately difficult material for adsorption of Zinc (n <2)

Meeting Development Challenges by Introducing Global ICT Standards to Agricultural Industry in Sri Lanka

Agriculture is the main source of livelihood of the rural population, whichaccounts for 70% of the total population in Sri Lanka besides issues related to theagricultural value chain, more specifically supply chain deficiencies are seriousdemanding urgent remedies. Meanwhile, the World Summit on the Information Society(WSIS) includes e-agriculture as an area of application of Information andCommunication Technologies (ICTs) to ensure the systematic dissemination ofinformation in order to provide ready access to comprehensive, up-to-date and detailedknowledge and information, particularly in rural areas. Although the digital presence ofmajority of Sri Lankan industry is commendable, agricultural industry is not anadequate level. One promising solution for this situation could be development of anonline trading portal.With the objective of rectifying the issues briefed above, by adopting designscience research methodology, proof-of-concept implementation of a trading portal foragriculture industry has been completed in this study. The information artifactsdeveloped in the research being thoroughly evaluated in laboratory with interestingresults and real world empirical evaluation is in the pipe-line of future work.Therefore, it is possible to claim that the portal developed is capable of reducingthe majority of supply chain deficiencies in agricultural trading while in compliancewith Global Electronic Business Collaboration Standards. In this work we have selectedrecommendation from United Nation‟s Center for Trade Facilitations and ElectronicBusiness (UN:CEFACT), i.e. UN:CEFACT‟s Modeling Methodology (UMM) andInternational Organization for Standardization (ISO) phases of a business processnamely planning, identification, negotiation, actualization and post-actualization.Among the contributions from this work, not only the operational trading portal but alsothe documented eCommerce solution developed approaches based on the globalstandards are central. The systematic eCommerce solution development methodologydocumented here could readily be re-used in many other trading scenarios fromdifferent domains.Key words: UN/CEFACT Modeling Methodology, REA Ontology, BusinessCollaboration Standard