A simulator for the control network of smart grid architectures

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Comparison of intelligent charging algorithms for electric vehicles to reduce peak load and demand variability in a distribution grid

A potential breakthrough of the electrification of the vehicle fleet will incur a steep rise in the load on the electrical power grid. To avoid huge grid investments, coordinated charging of those vehicles is a must. In this paper, we assess algorithms to schedule charging of plug-in (hybrid) electric vehicles as to minimize the additional peak load they might cause. We first introduce two approaches, one based on a classical optimization approach using quadratic programming, and a second one, market based coordination, which is a multi-agent system that uses bidding on a virtual market to reach an equilibrium, price that matches demand and supply. We benchmark these two methods against each other, as well as to a baseline scenario of uncontrolled charging. Our simulation results covering a residential area with 63 households show that controlled charging reduces peak load, load variability, and deviations from the nominal grid voltage

Distributed smart charging of electric vehicles for balancing wind energy

To meet worldwide goals of reducing CO2 footprint, electricity production increasingly is stemming from so-called renewable sources. To cater for their volatile behavior, so-called demand response algorithms are required. In this paper, we focus particularly on how charging electrical vehicles (EV) can be coordinated to maximize green energy consumption. We present a distributed algorithm that minimizes imbalance costs, and the disutility experienced by consumers. Our approach is very much practical, as it respects privacy, while still obtaining near-optimal solutions, by limiting the information exchanged: i.e. consumers do not share their preferences, deadlines, etc. Coordination is achieved through the exchange of virtual prices associated with energy consumption at certain times. We evaluate our approach in a case study comprising 100 electric vehicles over the course of 4 weeks, where renewable energy is supplied by a small scale wind turbine. Simulation results show that 68% of energy demand can be supplied by wind energy using our distributed algorithm, compared to 73% in a theoretical optimum scenario, and only 40% in an uncoordinated business-as-usual (BAU) scenario. Also, the increased usage of renewable energy sources, i.e. wind power, results in a 45% reduction of CO2 emissions, using our distributed algorithm

Escherichia coli RNA fragmenteerimine MazF ning MqsR toksiinide poolt

Väitekirja elektrooniline versioon ei sisalda publikatsiooneBakterite elu on täis väljakutseid: nad peavad toime tulema ohtlike kemikaalide, vaenulike naabrite ja toitainete puudusega. Erinevate ohtude vastu võitlemiseks on bakteritel välja arenenud mitmed stressile reageerimise mehhanismid. Bakteriaalsed toksiin-antitoksiin süsteemid on väikesed parasiitsed üksused, millest mõned on rakud suutnud värvata stressivastuse radadesse. Nendelt geneetilised üksustelt toodetakse raku kasvu pärssivat toksilist valku ja seda inaktiveerivat antitoksiini. Kuna antitoksiinid on ebastabiilseid tuleb neid stabiilsete toksiinide kontrolli all hoidmiseks pidevalt juurde toota. Seega, kui moodul peaks kaotsi minema või antitoksiinide tootmine on takistatud, vabanevad toksiinid ning pärsivad rakkude kasvu. Stressivastuses osalevaid toksiine peetakse peamiselt kasvuregulaatoriteks, mis vastusena kahjulikele teguritele vähendavad rakkude metaboolset aktiivsust. Hiljutised uurimused väidavad, et osadel toksiin-antitoksiini süsteemidel on rakus keerukam funktsioon - nad reguleerivad spetsiifiliste geenide avaldumist. Selle kõige silmapaistvamaks näiteks on Escherichia coli endoribonukleaasist toksiin MazF, mis arvatakse erinevate stresside korral ümberprogrammeerivat kogu raku translatsioonilise masinavärgi. Spekuleeritakse, et MazF muudab ribosoomide translatsioonilist eelistust eemaldades 16S rRNA küljest anti-Shine-Dalgarno järjestuse. Sellised ribosoomid arvatakse transleerivat kärbitud 5’ otstega stressiga seotud geenide mRNA-sid, mis on samuti MazFi poolt tekitatud. Me uurisime RNA lõikamist MazFi ja teise endoribonukelasse toksiini, MqsRi, poolt Escherichia colis ning ei näinud mingeid tõendeid, mis toetaks sellist keerukat translatsiooni ümberprogrammeerimise mehhanismi. Me näeme, et MazF ja MqsR käituvad ainult kui kasvupärssijad, mis lõikavad kõike kättesaadavat struktureerimata RNA-d. Traditsiooniliselt peetakse Escherichia coli endoribonukleaasidest toksiine ainult mRNA lagundajateks, kuid meie andmed viitavad sellele, et kasvu pidurdatakse ka läbi prekursor rRNA-de lagundamise.Lives of bacteria are full of perils: they have to cope with dangerous chemicals, hostile neighbours and limited nutrients. To counter various hazards, bacteria have developed many stress response mechanisms. Bacterial toxin-antitoxin systems are small parasitic modules, which have been in some cases also adopted into stress response pathways. These genetic units encode for an autotoxic protein and an antitoxin that neutralizes the toxin. Antitoxins are labile and need to be constantly produced to inhibit the extremely stable toxins. Thus, when the module is lost or antitoxin production gets hindered the toxins become free to inhibit the growth. Toxins involved in stress response are mainly considered to be regulators of growth, which reduce the metabolic activity of cells in response to harmful conditions. Recently, some toxin-antitoxin systems have been reported to have a more sophisticated function: the regulation of specific genes. The most prominent example is the MazF toxin of Escherichia coli, which is an endoribonuclease hypothesized to reprogram the translational machinery during various stresses. It is speculated that MazF removes a piece of the 3’ end from 16S rRNA in mature ribosomes, which results in altered translational specificity. Such modified ribosomes are thought to translate stress-related transcripts with truncated 5’ UTR-s, which are hypothesized to also be generated by MazF. We studied the RNA cleavage by MazF and another endoribonuclease toxin, MqsR, in Escherichia coli and saw no evidence for such elaborate translational reprogramming. Instead, we show that MazF and MqsR act as growth inhibitors, which cleave unstructured RNA. Traditionally, endoribonuclease toxins of Escherichia coli are viewed only as degraders of mRNA, but our data implies that growth arrest is also facilitated through degradation of precursor rRNA.https://www.ester.ee/record=b520943

Hearing Impairment Caused by Occupational Noise

Occupational noise-induced hearing impairment is an insidiously developing injury which only becomes apparent when it affects the hearing of conversational speech. As no remedy is possible, prevention is the only answer. In view of the impending legislation in South Africa a review of the literature is presented. This is confined to the auditory effects of potentially hazardous occupational noise in industry. Two principal properties of soundintensity and frequency-are briefly discussed. In the study of exposure to noise important factors are: (a) over-all noise level, (b) exposure duration in a working day, and (c) exposure duration over a working lifetime. The data derived from studies of hearing loss and of temporary threshold shift make it possible to predict the risk-percentage (incidence) and to some extent the amount of hearing loss resulting from exposure to a certain noise environment in the exposed population of workers. This enables appropriate authorities to set acceptable limits as criteria. If these are exceeded hearing conservation programmes, aimed at reducing the hazard, are indicated. Some features of these are mentioned and the value of audiometry is pointed out, especially for attempts to establish high susceptibility to suffer hearing loss in individuals. An outline of regulations regarding hearing impairment compensation in other countries is given. A few remarks are made on the role of the medical practitioner in industrial hearing conservation programmes