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In order to make sure of the safety of a long-span suspension bridge under earthquake action, this paper aims to study the traveling wave effect of the bridge under multi-support excitation and optimize the semi-active control schemes based on magneto-rheological (MR) dampers considering reference index as well as economical efficiency.

The finite element model of the long-span suspension bridge is established in MATLAB and ANSYS software, which includes different input currents and semi-active control conditions. Six apparent wave velocities are used to conduct non-linear time history analysis in order to consider the seismic response influence in primary members under traveling wave effect. The parameters α and β, which are key parameters of classical linear optimal control algorithm, are optimized and analyzed taking into account five different combinations to obtain the optimal control scheme.

When the apparent wave velocity is relatively small, the influence on the structural response is oscillatory. Along with the increase of the apparent wave velocity, the structural response is gradually approaching the response under uniform excitation. Semi-active control strategy based on MR dampers not only restrains the top displacement of main towers and relative displacement between towers and girders, but also affects the control effect of internal forces. For classical linear optimal control algorithm, the values of two parameters (α and β) are 100 and 8 × 10–6 considering the optimal control effect and economical efficiency.

The emphasis of this study is the traveling wave effect of the triple-tower suspension bridge under multi-support excitation. Meanwhile, the optimized parameters of semi-active control schemes using MR dampers have been obtained, providing relevant references in improving the seismic performance of three-tower suspension bridge.

The purpose of this paper is to find analytic approximate solutions for time-dependent flow and heat transfer of a Sisko fluid.

The homotopy analysis method is used to find a family of travelling wave solutions of the governing non-linear problem.

The effects of different parameters on the velocity and temperature profiles are shown graphically.

The analytic solutions of the system of non-linear ordinary differential equations are constructed in the series form for various values of the power index.

Under different ground motion excitation modes, the spatial coupling effect of seismic response for the arch bridge with thrust, seismic weak parts and the internal force components of the control section of main arch ribs are analyzed.

Taking a 490 m deck type railway steel truss arch bridge as the background, the dynamic calculation model of the whole bridge was established by SAP2000 software. The seismic response analyses under one-, two- and three-dimension (1D, 2D and 3D) uniform ground motion excitations were carried out.

For the steel truss arch bridge composed of multiple arch ribs, any single direction ground motion excitation will cause large axial force in the chord of arch rib. The axial force caused by transverse and vertical ground motion excitation in the chord of arch crown area is 1.4–3.6 times of the corresponding axial force under longitudinal seismic excitation. The in-plane bending moment caused by the lower chord at the vault is 4.2–5.5 times of the corresponding bending moment under the longitudinal seismic excitation. For the bottom chord of arch rib, the arch foot is the weak part of earthquake resistance, but for the upper chord of arch rib, the arch foot, arch crown and the intersection of column and upper chord can all be the potential earthquake-resistant weak parts. The normal stress of the bottom chord of the arch rib under multidimensional excitation is mainly caused by the axial force, but the normal stress of the upper chord of the arch rib is caused by the axial force, in-plane and out of plane bending moment.

The research provides specific suggestions for ground motion excitation mode and also provides reference information for the earthquake-resistant weak part and seismic design of long-span deck type railway steel truss arch bridges.

The great magnitude differences between the integral tunnel and its structure details make it impossible to numerically model and analyze the global and local seismic behavior of large-scale shield tunnels using a unified spatial scale, even with the help of supercomputers. The paper aims to present a combined equivalent & multi-scale simulation method, by which the tunnel's major mechanical properties under seismic loads can be represented by the equivalent model, and the seismic responses of the interested details can be studied efficiently by the coupled multi-scale model.

The nominal orthotropic material constants of the equivalent tunnel model are inversely determined by fitting the modal characteristics of the equivalent model with the corresponding segmental lining model. The critical sections are selected by comprehensive analyzing of the integral compression/extension and bending loads in the equivalent lining under the seismic shaking and the coupled multi-scale model containing the details of interest is solved by the mixed time explicit integration algorithm.

The combined equivalent & multi-scale simulation method is an effective and efficient way for seismic analyses of large-scale tunnels. The response of each flexible joint is related to its polar location on the lining ring, and the mixed time integration method can speed-up the calculation process for hybrid FE model with great differences in element sizes.

The orthotropic equivalent assumption is, to the best of the authors’ knowledge, for the first time, used in the 3D simulation of the shield tunnel lining, representing the rigidity discrepancies caused by the structural property.

The purpose of this paper is to report upon high power, internally matched GaN high electron mobility transistors (HEMTs) at Ku band with 1.5 GHz bandwidth, which employ a simple and cost‐effective lossless compensated matching technique.

Two 4 mm gate periphery GaN HEMTs are parallel combined and internally matched with multi‐section reactive impedance transformers at the input and output networks. The output matching network is designed at the upper frequency of the design band for a flat power of the circuit, while the input matching network is designed at the upper frequency for a flat gain.

With the reactively compensated matching technique, the internally matched GaN HEMTs exhibit a flat saturated output power of 43.2+0.7 dBm and an average power added efficiency of 15 per cent over 12 to 13.5 GHz.

This paper provides useful information for the internally matched GaN HEMTs.

To provide a list of non‐fictional books, as published, for the use of Librarians and Book‐buyers generally, arranged so as to serve as a continuous catalogue of new books ; an aid to exact classification and annotation ; and a select list of new books proposed to be purchased. Novels, school books, ordinary reprints and strictly official publications will not be included in the meantime.

Since early 2020, the world has faced a pandemic that has caused a disruption in our lives, the likes of which have never been seen before. The COVID-19 pandemic changed the way we live, work, communicate, socialize, travel and even plan our future life. The lockdowns and civilian and travel restrictions imposed by countries worldwide have drastically affected citizens' daily routines and mobility. In consequence, all sectors are currently struggling with an unprecedented crisis, as health-related concerns have substantial effects on travel industry at the local, national and global level. The current increase in mortality rate caused by the new coronavirus has affected individuals' risk and safety perceptions and consequently their travel behaviour.

A quantitative research methodology using an online questionnaire was implemented in Portugal, and a sample composed of 1900 answers collected during one year allowed to analyze the impact that the current pandemic has on people's safety and risk perceptions and how it is affecting their daily life and travel behaviours and their willingness to accept civilian and travel restrictions. The results confirmed that the pandemic had a strong impact on Portuguese residents' safety perceptions and their travel and tourism plans. Also, it was possible to conclude that those perceptions have changed over the course of three pandemic waves.

The discussion focuses on the kind of implications this situation may have for tourism destination management and marketing. Study limitations and guidelines for future research are also forwarded.

This article examines dynamic volatility spillovers between stock index returns of four main hospitality sub-sectors in US during the coronavirus disease 2019 (COVID-19) pandemic. These are tourism and travel, hotel and lodging, recreational services and food and beverages. Volatility spillovers are explicitly used as accurate and informative proxies for risk contagion between sectors during turbulent times.

The authors employ dynamic conditional correlation-generalized autoregression heteroskedasticity (DCC-GARCH) and wavelet coherence analysis (WCA) to analyze the phenomenon. The authors’ timeframe is divided into three main sub-periods, namely the pre-pandemic, the first wave and the second wave periods.

This study’s results reveal immense negative shocks in returns of all four sub-sectors on the Black Monday (8th March 2020). Moreover, high volatility persistence was observed during both waves with an exception of tourism and travel which exhibited lower volatility persistence during the second wave. The authors discovered magnified contagion effects between tourism and travel, hotel and lodgment and recreational services during the first wave of the pandemic with tourism and travel being the main volatility transmitter. Lower magnitudes of spillovers were observed between food and beverages and other sub-sectors with a decoupling effect being evident during the second wave.

This study’s findings contribute to the contagion theory by providing evidence of disproportional volatility spillover among hospitality sub-sectors despite being exposed to similar turbulent economic conditions.

Crucial implications can be drawn from this study’s findings to assist in risk management, asset valuation and portfolio management. The importance of close monitoring, safety measures, international diversification and adequacy of liquid assets during health crises cannot be stresses enough for hospitality firms. Retail investors, speculators and asset managers can take advantage of this study’s findings to design trading strategies and hedge against risk.

A body of knowledge pertaining to effects of crises such as COVID-19 on hospitality stocks has been proliferating. Nonetheless, there is still a relative dearth of empirical literature on volatility spillover between hospitality sub-sectors especially during periods of rising economic uncertainties.

The purpose of this paper is to assess the blast‐mitigation potential and the protection ability of an air‐vacated buffer placed in front of a target structure under realistic combat‐theatre conditions.

The blast‐mitigation efficacy of the air‐vacated buffer concept is investigated computationally using a combined Eulerian‐Lagrangian (CEL) fluid‐structure interaction (FSI) finite‐element analysis.

The two main findings resulting from the present work are: the air‐vacated buffer concept yields significant blast‐mitigation effects; and the buffer geometry and vacated‐air material‐state parameters (e.g. pressure, mass density, etc.) may significantly affect the extent of the blast‐mitigation effect.

The main contribution of the present work is a demonstration of the critical importance of timely deployment of the buffer relative to the arrival of the incident wave in order to fully exploit the air‐vacated buffer concept.