Three‐dimensional split‐step‐fourier and finite difference time domain‐based rectangular waveguide filter simulators: Validation,verification, and calibration

The split‐step‐Fourier‐based three‐dimensional wave propagation prediction and finite‐difference time‐domain‐based simulators are developed to show network scattering parameters of rectangular waveguide filters with horizontal and/or vertical windows as capacitive and/or inductive irises, respectively. The three‐dimensional‐split‐step parabolic equation simulator is applied to rectangular waveguide filters, and the results are compared with finite‐difference time‐domain model through tests inside a rectangular waveguide. © 2016 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:660–667, 2016.     

Empirical Predictive Models for Earthquake-Induced Sliding Displacements of Slopes

Earthquake-induced sliding displacement is the parameter most often used to assess the seismic stability of slopes. The expected displacement can be predicted as a function of the characteristics of the slope (yield acceleration) and the ground motion (e.g., peak ground acceleration), yet there is significant aleatory variability associated with the displacement prediction. Using multiple ground motion parameters to characterize the earthquake shaking can significantly reduce the variability in the prediction. Empirical predictive models for rigid block sliding displacements are developed using displacements calculated from over 2,000 acceleration–time histories and four values of yield acceleration. These empirical models consider various single ground motion parameters and vectors of ground motion parameters to predict the sliding displacement, with the goal of minimizing the standard deviation of the displacement prediction. The combination of peak ground acceleration and peak ground velocity is the two parameter vector that results in the smallest standard deviation in the displacement prediction, whereas the three parameter combination of peak ground acceleration, peak ground velocity, and Arias intensity further reduces the standard deviation. The developed displacement predictive models can be used in probabilistic seismic hazard analysis for sliding displacement or used as predictive tools for deterministic earthquake scenarios.     

QoS‐aware LTE‐A downlink scheduling algorithm: A case study on edge users

4G/LTE‐A (Long‐Term Evolution—Advanced) is the state of the art wireless mobile broadband technology. It allows users to take advantage of high Internet speeds. It makes use of the OFDM technology to offer high speed and provides the system resources both in time and frequency domain. A scheduling algorithm running on the base station holds the allocation of these resources. In this paper, we investigate the performance of existing downlink scheduling algorithms in two ways. First, we look at the performance of the algorithms in terms of throughput and fairness metrics. Second, we suggest a new QoS‐aware fairness criterion, which accepts that the system is fair if it can provide the users with the network traffic speeds that they demand and evaluate the performance of the algorithms according to this metric. We also propose a new QoS‐aware downlink scheduling algorithm (QuAS) according to these two metrics, which increases the QoS‐fairness and overall throughput of the edge users without causing a significant degradation in overall system throughput when compared with other schedulers in the literature.     

The value of an overseas research trip

As an essential part of the academic environment, international scientific mobility draws considerable attention from researchers. Previous studies have indicated a strong relationship between scientific mobility and scientific output. However, few researchers have addressed the causality between them. The research questions in this study focused on how the international scientific mobilization of the researchers affects their number of international collaborations, their ability to get published at higher impact factor journals, the number of citations that they get. Based on the SCOPUS database of English language scientific journal articles, this paper revealed the causal effects of international scientific mobility of the researchers on their scientific productivity, collaborations, and impact on science using the synthetic control method. The author’s affiliation on their articles provided the geographical location that can be tracked in time to infer the international scientific mobility of each author. A sample of more than 79,000 immobile scientists was used to create the synthetic versions of over 1500 internationally mobile scientists, so that, the synthetic version of each mobile author best resembled the academic ability of her/his counterpart mobile author in the pre-mobilization period. This allowed investigating the effects of the international mobilization on their publications by comparing the post-mobilization publication characteristics of the mobile authors and their immobile synthetic controls.The findings show strong evidence of a substantial positive effect of scientific mobility on the ability to get published in more prestigious journals, the number of citations received in total and from overseas, and international collaborations. The magnitude of the effect is conditional on the duration of scientific mobility.

     

Utilization of waste polyethylene terephthalate as a reducing agent in the reduction of iron ore composite pellets

The increasing consumption of plastics inevitably results in increasing amounts of waste plastics. Because of their long degradation periods, these wastes negatively affect the natural environment. Numerous studies have been conducted to recycle and eliminate waste plastics. The potential for recycling waste plastics in the iron and steel industry has been underestimated; the high C and H contents of plastics may make them suitable as alternative reductants in the reduction process of iron ore. This study aims to substitute plastic wastes for coal in reduction melting process and to investigate their performance during reduction at high temperature. We used a common type of waste plastic, polyethylene terephthalate （PET）, because of its high carbon and hydrogen contents. Composite pellets containing PET wastes, coke, and magnetite iron ore were reduced at selected temperatures of 1400 and 1450℃ for reduction time from 2 to 10 min to investigate the reduction melting behavior of these pellets. The results showed that an increased temperature and reduction time increased the reduction ratio of the pellets. The optimum experimental conditions for obtaining metallic iron （iron nuggets） were reduction at 1450℃ for 10 min using composite pellets containing 60% PET and 40% coke.     

Daphne oleoides: An alternative source of important sesquiterpenes

This study was targeted to characterize the chemical composition and antibacterial properties of Daphne oleoides subsp. oleoides essential oil. The essential oil was analyzed and quantified by gas chromatography and gas chromatography/mass spectrometry. Additionally, the broth dilution method was used to evaluate its antibacterial activity against Bacillus cereus (ATCC 11778), Bacillus subtilis (ATCC 6633), Staphylococcus aureus (ATCC 25923), Staphylococcus epidermidis (ATCC 12228), Streptococcus faecalis (ATTC 29212), Escherichia coli (ATCC 25922), Proteus mirabilis (ATCC 25933), Proteus vulgaris (ATCC 13315), Pseudomonas aeruginosa (ATCC 27853), and Salmonella typhi Ty2 (ATCC 19430). Seventy-nine compounds were identified, representing 95.2% of the total oil. Nootkatone (18.5%), nootkatin (12.1%), and daphnauranol C (11.7%) were determined as the main constituents in the oil. Oxygenated sesquiterpenes were dominating in the oil (43.0%), followed by fatty acid derivatives (13.7%) and carbonylic compounds (9.6%). The minimal inhibitory/bactericidal concentrations of essential oils of D. oleoides were in the range from 25–100 μg/mL, which can be considered as high activity in comparison with the reference antibiotic which was active in the rangefrom 3.12–100 μg/mL. The greatest minimal inhibitory concentration value was determined as 25 µg/mL against both two Bacillus strains and S. epidermidis, B. cereus, B. subtilis, and S. aureus were the most sensitive strains against essential oils when compared with the minimal inhibitory concentrations of control antibiotic. Consequently, Daphne oleoides subsp. oleoides can be exploited as a source of natural antibacterial agents and nootkatone for the pharmaceutical, food, and agricultural industries.     

Single‐chain polymer nanoparticles via click crosslinking and effect of photoinduced radical combination on crosslink points

Folding of azide functionalized polymer chains was obtained via the copper‐catalyzed azide alkyne cycloaddition (CuAAC) methodology using a light‐responsive crosslinker as the ‘click’ component. Subsequently, crosslinked junction points were combined with a photoinduced radical combination strategy to achieve more compact nanoparticles. The resultant folding particles possess smaller particle sizes and higher glass transition temperature values compared to their linear analogues. Fourier transform IR spectroscopy, SEC, DSC, dynamic light scattering, ¹H NMR and TEM techniques were used for characterization. © 2020 Society of Chemical Industry     

Probabilistic Seismic Hazard Analysis for the Sliding Displacement of Slopes: Scalar and Vector Approaches

Sliding block displacements often are used to evaluate the potential for ground failure due to slope instability. The procedures used to assess sliding block displacement typically use deterministic or pseudoprobabilistic approaches, in which the uncertainties in the expected ground motion and resulting displacement are either ignored or not treated in a rigorous manner. Thus, there is no concept of the actual hazard associated with the computed displacement. This paper presents a fully probabilistic framework for assessing sliding block displacements. The product of this analysis is a displacement hazard curve, which provides the annual rate of exceedance, λ, for a range of displacement levels. The framework considers two procedures that will yield a displacement hazard curve: (1) a scalar hazard approach that utilizes a single ground motion parameter and its associated hazard curve to compute permanent displacements; and (2) a vector hazard approach that predicts displacements based on two (or more) ground motion parameters and the correlation between these parameters. The vector approach reduces the displacement hazard significantly, as compared with the scalar approach, because of the reduction in the variability in the displacement prediction. Comparison of the fully probabilistic approach with an approach using probabilistically derived ground motions reveals that using a ground motion for a given hazard level does not produce a displacement level with the same hazard.