Nonlinear analysis of biomagnetic signals recorded from uterine myomas

OBJECTIVE: To determine if there is any non-linearity in the biomagnetic recordings of uterine myomas and to find any differences that may be present in the mechanisms underlying their signal dynamics. METHODS: Twenty-four women were included in the study. Sixteen of them were characterised with large myomas and 8 with small ones. Uterine artery waveform measurements were evaluated by use of Pulsatility Index (PI) (normal value PI<1.45). RESULTS: Applying nonlinear analysis to the biomagnetic signals of the uterine myomas, we observed a clear saturation value for the group of large ones (mean = 11.35 ± 1.49) and no saturation for the small ones. CONCLUSION: The comparison of the saturation values in the biomagnetic recordings of large and small myomas may be a valuable tool in the evaluation of functional changes in their dynamic behavior

Numerical analysis of stress concentration factors on tensile armour wires inside the end-fitting of an axially tensed unbonded flexible pipe

The present paper examines the case of a metal based unbonded flexible pipe under a number of axial tensile operational loads of varying intensity, expressly focusing on the response of the segments of the pipe’s tensile armour wires that lie inside the pipe’s End-Fitting (EF), with intent to track the development of high stress concentration areas there and assess the stress concentration factors (SCF) involved. Additionally, a parametric study is performed, to identify potential factors that might affect the maximum SCF values measured on these wire segments inside the EF. Based on the parametric study’s findings, an approximate relationship for evaluating the expected maximum SCF on the tensile wire inside the EF is developed. The paper adopts a numerical approach to the problem, based on the development of a two-dimensional finite element model for evaluating the wire’s response to axial tensile operational loads. The model considers both the effects the EF’s assembling procedure and the Factory Acceptance Test (FAT) have on the behavior of wire segments lying inside the EF. An analytical approach is employed as a benchmarking tool of the numerical model’s performance

Stress state of unbonded flexible pipe’s tensile armour wires inside end-fittings

The present paper addresses the stresses developing, inside the End-Fitting (EF), on the tensile armour wires of a metal based unbonded flexible pipe under axial tensile operational loads. To this end, a bi-dimensional finite element model that estimates the stress state of tensile armour wires inside the EF is developed. The stresses induced during the EF assembling procedure as well as the Factory Acceptance Test (FAT) are considered in the developed numerical model. An analytical approach to this problem, suggested by Campello (2014) and Campello et al. (2016), is utilized as a benchmarking tool in order to evaluate the developed numerical model’s performance. The results obtained show good agreement between the developed model and the analytical approach. A high concentration of stresses on the tensile armour wires inside the EF, at a key point near the EF’s entrance, is observed under all operational load cases. Moreover, the results suggest that the EF assembly procedure and the FAT test need to be indeed considered, as they yield significant residual stresses on the tensile armour wires inside the EF

Performance-Risk Nexus of Global Low-Rated ETFs During the QE-Tapering Period

This study investigates the performance of 50 global, one star (based on Morningstar rankings), ETFs during the US QE-tapering period starting in October 2014 up to September 2018, using the S&P500 as the market index. The methodology employed is based on the CAPM model. We adopt the Jensen’s Alpha, Beta, a / b, Sharpe and Treynor ratios measures in order to examine whether those ETFs have achieved abnormal returns. We conclude that managers of most ETFs do not exhibit selectivity skills and only six of these ETFs achieve higher returns than the market by showing bullish behavior. At the same time, most ETFs have positive Sharpe and Treynor ratios due to high expected returns during the period under scrutiny

Effects of Carbon Taxation, Distributed Generation and Electricity Storage Technologies on a Microgrid

AbstractDistributed generation along with combined heat and power production and electricity stora e technologies can offer important benefits from economic but also environmental point of view. Carbon taxation has a serious impact on the function of a Microgrid. This analysis uses the Distributed Energy Resources – Customer Adoption Model to meet the annual load of an existing hotel in Athens choosing the optimal combination of installed technol gies and their operating schedule. The installation of reciprocating engines and lead acid batteries contributes to a cost saving up to 25% and a eduction in carbon emissions up to 10%, using a realistic carbon tax and under ideal circumstances. Various scenarios with different carbon taxes and available technologies were executed. The installation of photovoltaic systems appears more economical when the carbon tax increases significantly

Feature-based SpMV Performance Analysis on Contemporary Devices

The SpMV kernel is characterized by high performance variation per input matrix and computing platform. While GPUs were considered State-of-the-Art for SpMV, with the emergence of advanced multicore CPUs and low-power FPGA accelerators, we need to revisit its performance and energy efficiency. This paper provides a high-level SpMV performance analysis based on structural features of matrices related to common bottlenecks of memory-bandwidth intensity, low ILP, load imbalance and memory latency overheads. Towards this, we create a wide artificial matrix dataset that spans these features and study the performance of different storage formats in nine modern HPC platforms; five CPUs, three GPUs and an FPGA. After validating our proposed methodology using real-world matrices, we analyze our extensive experimental results and draw key insights on the competitiveness of different target architectures for SpMV and the impact of each feature/bottleneck on its performance