Celebrating Economies of Change: Brave Visions for Inclusive Futures

This issue has been inspired by a path-breaking conference held by the Canadian Society for Ecologi-cal Economics (CANSEE), which took place this past May 2019 in Waterloo, Ontario. Entitled Engaging Economies of Change, the conference aimed to ex-pand existing research networks in the economy-environment nexus by building connections beyond the academy in order to meaningfully engage with the practicalities of building and implementing change. This issue captures the rich content shared during the event, as well as descriptions of the pro-cesses and efforts made to create a welcoming and respectful space where academics and community activists could build alliances and discuss common challenges. The conference organizers – all graduate students and activists themselves -- called this ‘building a brave space’.This research was supported by the Social Sciences and Humanities Research Council of Canad

Elpusztított emlékhelyek

A Magyar Királyi Csendőrségnek négy emlékhelye volt, közülük hármat Budapesten helyezték el a két világháború között, a negyediket Nyitra vármegyében a dualizmus időszakában hozták létre

Sequence impedances of land single-core insulated cables: Direct formulae and multiconductor cell analyses compared with measurements

The paper deals with the sequence impedances (positive/negative and zero sequences) of high- and extra-high-voltage land single-core insulated cables. In particular, it presents the comparisons between sequence impedance measurements and computations. The computations of the sequence impedances are carried out by means of the most important international normative and council references (IEC/Cigr\ue9) and of multiconductor cell analysis which is a consolidated and powerful tool developed by University of Padova in order to analyse power frequency regimes of multiconductor asymmetric power systems. The comparisons are presented with reference to four high- and extra-high voltage insulated cables, even if the available ones are much higher: however, the conclusions derived from these four reference cases are general and can be useful for transmission system operators and for power electric system engineers involved in insulated cables. The paper demonstrates, for the first time in technical literature, that direct formulae cannot correctly evaluate the sequence impedances of installed single-core land cable systems. Extensive on-field measurement campaigns have served to this purpose

269. Pediatric front to back X-ray chest exposure: Image quality and dose optimization

In this study we changed the acquisition parameters in chest X-ray of 5 years old pediatric patients in order to lower radiation dose and preserve image quality. A new acquisition technique (T2) was compared to the previous (T1). The comparison regarded dosimetric and a qualitative assessment on phantom and on patients

270. X-ray acquisition of extremities: Image quality and dose optimization

PurposeIn this study we changed acquisition parameters in X-ray acquisition of extremities (kV, mA, s and focal spot) trying to improve high and contrast resolution. The new technique (T2) was compared to a technique (T1) presenting the default parameter set by the manufacturer. The comparison regarded a dosimetric and a qualitative assessment [1]

3D MCA Validation by the Harmonic Measurement Campaign on the Sicily-Malta HV Three-Core Submarine Cable

The paper deals with a final experimental validation of three-dimensional Multiconductor Cell Analysis (MCA) developed by the Electric Energy Transmission Laboratory of the University of Padova. This final confirmation comes from the measurement campaign carried out on one of the longest (100 km) HVAC submarine three-core cables in the world: the Sicily-Malta interconnector. The considered frequency measurements range from 0 to 40th harmonic order with both positive and zero sequence supplies. In this overall harmonic interval and with both supplies, the comparison between measurements and MCA results highlights a very good agreement (maximum differences of 10 %). These differences are negligible if measurement uncertainties are considered

A Novel Dynamic Load Modeling for Power Systems Restoration: An Experimental Validation on Active Distribution Networks

In this paper, a novel approach to assess the power demand of distribution networks during a restoration process following an outage is presented. The possibility of correctly estimating such power demand represents a very important support in the choice and management of reliable restoration paths which significantly contributes to increase the resilience of the power system. In fact, due to the ever-growing penetration of renewable energy sources in the worldwide networks, electrical systems are often pushed to operate closer to their design limits and so, in particular conditions, black outs can be more frequent compared to the past. In this context, the aim of this work is to develop a general expression which can consider and represent all the key elements which affect the active and reactive power demand of distribution grids during the restoration process. The proposed method considers also the relationship between distributed generation and frequency behaviour in the power demand estimation. This aspect is generally neglected in literature although it has a significative impact. The effectiveness of the present approach is experimentally demonstrated on field. More specifically, the developed tool is applied to estimate the power demand of two real distribution networks and the tool results are compared with on-field recordings. This comparison demonstrates that the proposed approach represents a promising tool which, together with the restoration tests, could be an important ally in the design and management of the restoration plan of electrical networks

HVAC Single Core Insulated Cables with Steel Reinforced Mechanical Protections: Effect on Sequence Impedances

In this paper the sequence impedances of an existing HVAC insulated cable, protected by a steel reinforced concrete structure, are estimated. The paper aims at investigating if the presence of metallic protective structures significantly affects the sequence impedances of the line. The present analyses are carried out by applying both the multiconductor cell analysis and the finite element method in order to model the HVAC line with and without protective structure. The results arising from the use of the different modelling approaches are compared