The arrival of modern protection relays on distribution networks offers us an excellent opportunity to better understand the performance of network protection and to efficiently identify coordination problems. The analysis of relay event reports helps establishing the source of unnecessary relay protection tripping. In this work, the analysis of measurements of digital over-current relays is conducted. The case study is focused on performing a macro level analysis of protection coordination on Hydro-Québec's distribution network. Additionally, a characterisation of short circuits has been performed. A list of observations followed by recommendations for improvement of relay protection strategy in distribution networks is presented using the results of this case study.

This paper explores the use of microgrids during cold-load pickup (CLPU) phenomena, which are typical after an outage in distribution networks with high share of ther-mostatically controlled load (TCL). We present a mixed-integer linear programming (MILP) formulation for scheduling service restoration (SR). The proposed model computes the optimal re-connection sequence, generation and storage levels for the microgrids as well as power supply level from the main grid. The model is tested on different modifications of the IEEE-13 feeder network. The proposed approach is suitable for practical SR scheduling and to test the CLPU capabilities of a distribution network during the planning process.

The growing penetration of renewable resources such as wind and solar into the electric power grid through power electronic inverters is changing the grid dynamics and challenging grid protection. Due to the advanced inverter control algorithms, the inverter-based resources present fault responses different from conventional generators, which can fundamentally affect the way that the power grid is protected and thus is challenging grid protection engineers. This paper studies inverter dynamics during the system restoration period and their impact on protection schemes in a grid-connected solar photovoltaic (PV) system following grid disturbances. To this end, the solar PV system with a detailed inverter model that consider inverter switching dynamics along with inverter blocking and deblocking functions are constructed for the hardware-in-loop simulation based on a real-time digital simulator (RTDS). It is found that undesired transient events such as three-phase overvoltage and overcurrent as well as negative sequence current may occur after the inverter is deblocked to reinject energy into the system during the restoration period following a grid disturbance, especially when the system is under weak grid conditions. The undesired transient events may lead to misoperation of instantaneous overcurrent and negative sequence overcurrent protection schemes.

The increasing penetration of inverter-based resources (IBRs) is changing grid dynamics and challenging safe and reliable grid operation. Particularly, the increasing integration of IBRs may cause the small-signal stability issues resulting from the dynamic interaction between the IBR inverter controls and the power network in a power system with high penetration of IBRs. It is challenging for assessing the small-signal stability in such a power system due to the complex interaction between IBRs interconnected through the power network. The assessment complexity is further increased when considering variable IBR generation. To address the challenges, this paper proposes a method for small-signal stability analysis of a multi-IBR power system under uncertain renewable generation. First, we derive that the small-signal stability of a multi-IBR power system can be estimated based on the smallest eigenvalue of a weighted Laplacian matrix of the power network. Then, a robust optimization problem is formulated to analyze the small-signal stability of a multi-IBR power system under variable renewable generation. The efficacy of the proposed method is demonstrated on a power system with three IBRs by eigenvalue analysis and electromagnetic transient simulations.

Background: Weight gain is becoming increasingly prevalent amongst people with HIV (PWH) receiving contemporary antiretroviral treatment. We investigated BMI changes and clinical impact in a large prospective observational study. Methods: PWH aged ≥18 years were included who started a new antiretroviral (baseline) during 2010–2019 with baseline and ≥1 follow-up BMI assessment available. Rates of clinical outcomes (cardiovascular disease [CVD], malignancies, diabetes mellitus [DM] and all-cause mortality) were analysed using Poisson regression to assess effect of time-updated BMI changes (>1 kg/m2 decrease, ±1 kg/m2 stable, >1 kg/m2 increase), lagged by 1-year to reduce reverse causality. Analyses were adjusted for baseline BMI plus key confounders including antiretroviral exposure. Results: 6721 PWH were included; 72.3% were male, median age 48 years (interquartile range [IQR] 40–55). At baseline, 8.4% were antiretroviral-naive, and 5.0% were underweight, 59.7% healthy weight, 27.5% overweight, and 7.8% were living with obesity. There was an 8.2% increase in proportion of overweight and 4.8% in obesity over the study period (median follow-up 4.4 years [IQR 2.6–6.7]). 100 CVDs, 149 malignancies, 144 DMs, and 257 deaths were observed with incidence rates 4.4, 6.8, 6.6, 10.6 per 1000 person-years of follow-up, respectively. Compared to stable BMI, >1 kg/m2 increase was associated with increased risk of DM (adjusted incidence rate ratio [IRR]: 1.96, 95% confidence interval [CI]: 1.36–2.80) and >1 kg/m2 decrease with increased risk of death (adjusted IRR: 2.33, 95% CI: 1.73–3.13). No significant associations were observed between BMI changes and CVD or malignancies. Conclusions: A BMI increase was associated with DM and a decrease associated with death.

This work demonstrates the design, implementation, and experimental results of a low-cost disposable flexible sensor system capable of both impact localization and measurement. The proposed flexible sensor structure utilizes a special series of Bristol paper as the main fabrication material, which is coated with electric paint graphite paste and silver paste. The implemented sensor system uses a planar absolute encoder-like sensing topology to locate the impact and has a low-cost and quick manufacturing process. The size of the structure is <inline-formula> <tex-math notation="LaTeX">${210}\times {18}.{56}$ </tex-math></inline-formula> mm with a thickness of approximately 340 <inline-formula> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula>. It has an electronic read-out consisting of three identical Wheatstone bridge circuits and instrumentation amplifiers for each bit. It can detect the external forces in the range of 0.6N to 12N with a spatial resolution of 2.4 cm and 0.55 cm in horizontal and vertical axes, respectively. The proposed sensor structure is tested in a series of experiments using a robotic setup consisted of a pantograph mechanism and a direct drive linear motor. The experiments illustrate the results with measurement sensitivity as small as 1N and proper fatigue resilience against repetitive loads.

To achieve the highest possible agricultural production, it is necessary to procure the appropriate agricultural machinery. A tractor is the most useful machine in agriculture that performs various functions. Therefore, the selection of a tractor is one of the key decisions in the agriculture-production process. This study aims to evaluate heavy tractors for agricultural production in Bosnia and Herzegovina. Since this is a selection between different tractors, which are evaluated using several criteria, the methods of multi-criteria analysis (MCDA) were used in this study. Five different methods were used to determine the weight of the criteria, of which a modified standard-deviation method is a new method used in practice, while the tractor ranking was performed using the CRADIS (compromise ranking of alternatives from distance to ideal solution) method. The results showed that the best-ranked tractor is A4, while the most deviations from the ranking occur when the entropy method is used. The contribution of this study is in the systematization of the methods for the objective determination of the criteria weights and the development of new methods to facilitate decision-making in agriculture and other industries.

Cilj ovog rada bio je ispitati utjecaj termičke obrade kuhanjem na sadržaj željeza (Fe), cinka (Zn), bakra (Cu) i magnezija (Mg) u mišićnom tkivu i jetri junadi u ovisnosti od sustava tova iz kojeg životinje potječu. Istraživanje je provedeno na uzorcima mišićnog tkiva (but i plećka) i jetre junadi u dobi od 9 do 12 mjeseci koja su tovljena ekstenzivno (n=12) ili intenzivno (n=12). Svaki uzorak je podijeljen na dva jednaka dijela od kojih je jedan analiziran u sirovom stanju, a drugi nakon termičke obrade kuhanjem u vodi na 100°C. Rezultati su iskazani u apsolutno suhoj tvari mesa. Sadržaj pepela (mineralnog ostataka) u termički obrađenim uzorcima bio je smanjen u odnosu na sirove uzorke, ali to nije bilo praćeno značajmeso junadi, termička obrada, minerali nim promjenama u sadržaju Fe, Zn i Cu u mišićnom tkivu, niti promjenama Zn i Cu u jetri. Termička obrada dovela je do smanjenja sadržaja Mg u svim ispitivanim partijama mesa (za 40-50%), a do smanjenja sadržaja Fe došlo je samo u jetri (za 25-42 %). Učinak termičke obrade na sadržaj ispitivanih minerala u mišićnom tkivu i jetri bio je neovisan od sustava tova, iako su razlike po sustavu tova bile evidentne kod svih ispitivanih minerala, osim kod Fe. Sadržaj Zn u mišićnom tkivu buta junadi iz ekstenzivnog tova bio je manji, a sadržaj Cu veći u odnosu na uzorke buta iz intenzivnog sustava tova. Suprotno od buta, u jetri je sadržaj Cu bio veći kod junadi iz intenzivnog tova. U svim ispitivanim partijama mesa iz ekstenzivnog tova sadržaj Mg je bio značajno veći nego kod junadi iz intenzivnog tova.

Purpose Treatment of distal vessel occlusions causing incomplete reperfusion after mechanical thrombectomy (MT) is debated. We hypothesized that pretreatment with intravenous thrombolysis (IVT) may facilitate delayed reperfusion (DR) of residual vessel occlusions causing incomplete reperfusion after MT. Methods Retrospective analysis of patients with incomplete reperfusion after MT, defined as extended thrombolysis in cerebral infarction (eTICI) 2a–2c, and available perfusion follow-up imaging at 24 ± 12 h after MT. DR was defined as absence of any perfusion deficit on time-sensitive perfusion maps, indicating the absence of any residual occlusion. The association of IVT with the occurrence of DR was evaluated using a logistic regression analysis adjusted for confounders. Sensitivity analyses based on IVT timing (time between IVT start and the occurrence incomplete reperfusion following MT) were performed. Results In 368 included patients (median age 73.7 years, 51.1% female), DR occurred in 225 (61.1%). Atrial fibrillation, higher eTICI grade, better collateral status and longer intervention-to-follow-up time were all associated with DR. IVT did not show an association with the occurrence of DR (aOR 0.80, 95% CI 0.44–1.46, even in time-sensitive strata, aOR 2.28 [95% CI 0.65–9.23] and aOR 1.53 [95% CI 0.52–4.73] for IVT to incomplete reperfusion following MT timing <80 and <100 min, respectively). Conclusion A DR occurred in 60% of patients with incomplete MT at ~24 h and did not seem to occur more often in patients receiving pretreatment IVT. Further research on potential associations of IVT and DR after MT is required.

A graph convolutional network (GCN) is employed in the deep energy method (DEM) model to solve the momentum balance equation in three‐dimensional space for the deformation of linear elastic and hyperelastic materials due to its ability to handle irregular domains over the traditional DEM method based on a multilayer perceptron (MLP) network. The method's accuracy and solution time are compared to the DEM model based on a MLP network. We demonstrate that the GCN‐based model delivers similar accuracy while having a shorter run time through numerical examples. Two different spatial gradient computation techniques, one based on automatic differentiation (AD) and the other based on shape function (SF) gradients, are also accessed. We provide a simple example to demonstrate the strain localization instability associated with the AD‐based gradient computation and show that the instability exists in more general cases by four numerical examples. The SF‐based gradient computation is shown to be more robust and delivers an accurate solution even at severe deformations. Therefore, the combination of the GCN‐based DEM model and SF‐based gradient computation is potentially a promising candidate for solving problems involving severe material and geometric nonlinearities.