GIC immune transformers - An evaluation of their GIC elimination and fault behaviour

Geomagnetically Induced Currents (GICs) arise from fluctuations in Earths magnetic field and can reach alarmingly high levels and cause malfunctions or blackouts in the power grids in which they occur. AF Klercker Alaküla and Lindahl invented a patented GIC immune transformer which eliminates the effects of GICs, though it is not known how this implementation will affect the transformers behavior during un-symmetrical faults. This project aims to clarify the impact of the patented implementation, with regard to fault current and voltage rise at single-line-to-ground faults, as well as verify the beneficial effects on GICs. Experiments on lab transformers corresponding to the specifications in the mentioned patent and simulations of a full scale equivalent were performed. Both the experiment and simulation results show that the GIC immune transformer eliminates the effects of GIC. The simulations also indicate that the fault current, of a bolted single-line-to-ground fault, is increased, and the voltages decreased, by replacing a regular transformer with the patented implementation. For unaltered current and voltages a grounding reactance can be used. The work shows that such a reactance should be the sum of the uncompensated grounding reactance and one third of the transformers uncompensated zero-sequence reactance

Transport in supply networks

Purpose The purpose of the paper is to analyse how transport activities are embedded in supply chains and networks. Design/methodology/approach The paper is empirically grounded in a single case study that describes and analyses a supply chain of a particular product, Geocloth, focussing on how transport activities are organised in the supply network. Findings The paper concludes that transport activities are embedded in two related settings - the supply chain setting and the transport network setting - with implications for how adjustments can be made to increase transport performance. Furthermore, the paper shows how transport performance can be analysed as a function of how business relationships are connected vertically (i.e. how transport activities are sequentially connected within supply chains) and horizontally (i.e. how transport activities are connected across supply chains with regard to joint resource use). Originality/value The paper contributes to the understanding of how transport is integrated in supply networks by focussing on the connections between business relationships in supply chains and by pointing to how transport activities are embedded both in supply chain settings and in transport network settings

Sociala medier i anställningsförhållandet

I takt med den tekniska utvecklingen blir det allt lättare för individen att yttra sig inför en mängd människor. Yttranden som tidigare haft en liten spridning kan idag via en snabb knapptryckning nå ut till en stor publik. Syftet med uppsatsen är att undersöka vad en arbetstagare inom offentlig respektive privat sektor får uttrycka via sociala medier i förhållande till yttrandefriheten och lojalitetsplikten. Offentliganställda kan tack vare yttrandefrihetsregleringen i RF och YGL i stor utsträckning uttala sig via sociala medier men hänsyn måste tas till lojalitetsplikten som följer av anställningsavtalet. Yttrandefriheten inskränker dock lojalitetsplikten vilket innebär att arbetsgivare inom offentlig sektor i de flesta fall inte kan vidta åtgärder till följd av en arbetstagares uttalande via sociala medier, även då det orsakat att allmänheten tappat förtroende för verksamheten. Inom privat sektor är arbetstagarens möjlighet att uttrycka sig via sociala medier inte lika stor. Detta eftersom grundlagarna inte är tillämpliga och lojalitetsplikten istället sätter ramarna för vad arbetstagaren får uttrycka via sociala medier. Yttrandefriheten regleras även av artikel 10 i EKMR som omfattar arbetstagare inom både offentlig och privat sektor. Offentligt anställda skyddas eftersom den riktar sig till det allmänna medan privatanställda skyddas via statens positiva förpliktelser att även säkerställa yttrandefriheten mellan enskilda individer.In todays technological society it is becoming easier and easier for an individual to voice their opinion to a big crowd. Opinions, which previously had a small spread, can today through the click of a button reach a large audiance. The purpose of this thesis is to investigate how the freedom of expression and duty of loyalty influence the possibilities of an employee within private and public sector to express their opinion on social media. Employees within public sector are to a large degree able to express themself through social media since the Swedish constitutions RF and YGL guarantees freedom of expression. Nevertheless the employees still has to act accordingly to the principle of duty of loyalty. However, the right to freedom of expression is superior to the duty of loyalty and therefore the employer in most cases cannot carry out actions, due to an employees’ opinion. In the private sector the situation is different since the Swedish constitutions are not applicable and therefore the duty of loyalty is superior and it gives the employer a greater possibility to carrying out actions against the employee. Through article 10 of the European Convention of Human Rights, the freedom of expression is regulated. The article applies to the public sector and in certain cases the member states have a positive obligation to protect the right to freedom of expression between private individuals

Life cycle assessment of fish oil substitute produced by microalgae using food waste

Fish oil has been used in conventional aquaculture for decades, despite the known links between increasing global demand for fish and depletion of natural resources and vital ecosystems (FAO, 2020, 2019). Alternative feed ingredients, including algae oil rich in docosahexaenoic acid (DHA), has therefore been increasingly used to substitute traditional fish oil. Heterotrophic algae cultivation in bioreactors can be supported by a primary carbon feedstock recovered from food waste, a solution that could reduce environmental impacts and support the transition towards circular food systems. This study used life cycle assessment to quantify environmental impact of DHA produced by the heterotrophic algae Crypthecodinium cohnii, using short-chain carboxylic acids derived from dark fermentation of food waste. The future potential of DHA from algae was evaluated by comparing the environmental impact to that of DHA from Peruvian anchovy oil. With respect to global warming, terrestrial acidification, freshwater eutrophication and land use, algae oil inferred -52 ton CO2eq, 3.5 ton SO2eq, -94 kg Peq, 2700 m2 eq, respectively per ton DHA. In comparison, the impact per ton DHA from fish oil was -15 ton CO2eq, 3.9 ton SO2eq, -97 kg Peq and 3200 m2 eq. Furthermore, algae oil showed lower climate impact compared to canola and linseed oil. By including Ecosystem damage as indicator for ecosystem quality at endpoint level, the important aspect of biodiversity impact was accounted for. Although the method primarily accounts for indirect effects on biodiversity, DHA from algae oil showed lower Ecosystem damage compared to fish oil even when future energy development, optimized production, increased energy demand and effects on biotic resources were considered via sensitivity analyses. As the results suggest, algae oil holds a promising potential for increased sustainability within aquaculture, provided that continued development and optimization of this emerging technology is enabled through active decision-making and purposeful investments

The role of public actors in construction logistics: effects on and of relational interfaces

Public actors are increasingly enforcing the use of specifically designed construction logistics setups (CLS) to cope with logistical challenges and minimising disturbances on third parties in large construction projects. The organising of these CLS is contingent on the interaction among several types of actors. The purpose of the paper is to advance the understanding of the design and use of CLS and the distribution of various outcomes of such arrangements on the actors involved. The paper analyses the role of public actors in the initiating of CLS and how this affects the relational interfaces in the CLS triad of developers, contractors and logistics service providers, and the outcomes of their interactions. First, the main reason for a public actor to initiate a CLS is not cost, productivity or innovativity gains, but to decrease disturbances on third parties. Second, developers and contractors are forced to use the CLS initiated by the public actor. This makes them take on a forced customer role, explaining why these actors are often resistant to adopt to a certain CLS. Third, ripple effects, such as unintended costs and productivity impacts, occur in the construction supply chain because of the use of CLS

FuSSI-Net: Fusion of Spatio-temporal Skeletons for Intention Prediction Network

Pedestrian intention recognition is very important to develop robust and safe autonomous driving (AD) and advanced driver assistance systems (ADAS) functionalities for urban driving. In this work, we develop an end-to-end pedestrian intention framework that performs well on day- and night- time scenarios. Our framework relies on objection detection bounding boxes combined with skeletal features of human pose. We study early, late, and combined (early and late) fusion mechanisms to exploit the skeletal features and reduce false positives as well to improve the intention prediction performance. The early fusion mechanism results in AP of 0.89 and precision/recall of 0.79/0.89 for pedestrian intention classification. Furthermore, we propose three new metrics to properly evaluate the pedestrian intention systems. Under these new evaluation metrics for the intention prediction, the proposed end-to-end network offers accurate pedestrian intention up to half a second ahead of the actual risky maneuver.Comment: 5 pages, 6 figures, 5 tables, IEEE Asilomar SS