Vertical evacuation in hurricanes: An urgent policy problem for coastal managers

Abstract

Evacuation inland ("horizontal evacuation") is the traditional method of saving life in areas forecast as the site of hurricane landfall. But “high confidence”; warning time is only 12 hours, while some coastal areas are now so densely populated that twice that time is required for evacuation. Coastal managers must therefore risk the ire of local citizens “unnecessarily”; evacuated early, and the associated risk that several false alarms will reduce citizen compliance, or the risk that evacuation will be too long delayed.

The alternative of vertical evacuation (going upstairs in hurricane‐proof buildings) is resisted by planners who are concerned that its risks are too high and that partial acceptance of the concept would vitiate compliance with the horizontal component. But in some areas there may no longer be a choice: prudent coastal managers must determine the potential need and capability for vertical evacuation in their areas. Effective integration of both vertical and horizontal evacuation will require development of new plans and policies.     

Objective evaluation of door-closing sound quality based on physiological acoustics

This paper presents a new method to objectively quantify the sound quality of doors closing in premium passenger cars. In previous works, psychoacoustic parameters have been used for objective quantification. However, these parameters do not agree well with subsequent subjective assessments. Therefore, the correlation between the psychoacoustic parameters and the subjective rating of door closing sounds in sampled cars is low, and it is not sufficient to use psychoacoustic parameters as an objective metric to quantify the quality of door-closing sounds. In this paper, a new method is proposed to objectively quantify the sound quality based on physiological acoustics and statistical signal processing. A gammatone filter is used as a pre-processing method in models of the auditory system and kurtosis, which is the fourth-order moment of the temporal signal and is used to extract quantitative information about the quality of door-closing sounds. The new metric obtained from the proposed method is highly correlated to subjective ratings and has been successfully applied to the quantification of door-closing sound quality.     

High-Speed Generators for Power-Dense, Medium-Power, Gas Turbine Generator Sets

Concepts to improve turbine generator (TG) set power density (PD) are identified, developed, and evaluated. The evaluation focuses on the TG set as a part of overall system optimization, with weight and volume penalties for special auxiliaries. PD is given priority, while other attributes such as efficiency, acoustics, and total system cost are also assessed. The strengths and weaknesses of each concept are assessed based on technical viability, potential for PD improvement, and risk. Sixty-one generator concepts over four generator types—air-cooled wound field, water-cooled wound field, permanent magnet (PM), and high-temperature superconducting (HTS)—are evaluated with three ship-level electrical distribution architectures—high-frequency AC and active- and passive-rectified DC. A prime mover of 14 MW at 7,000 r.p.m. is assumed. The study assesses generator size enabled by directly coupling the generator to the prime mover, eliminating the typical gear required in TG sets with engine speeds greater than 3,600 r.p.m. Technology approaches are described and trends in the design data are identified. Advanced PM and superconducting rotor technologies are evaluated. For the power, speed, and system requirements studied, these technologies do not differ significantly from water-cooled designs in size and weight. A water-cooled generator would be compatible with a range of future power distribution systems such as high-frequency AC, rectified DC, or 60 Hz AC (using a rectifier and an inverter).     

Numerical Analysis of Thermal Distortion and Residual Stresses in H13 Steel Due to Vacuum Gas Quenching

IntroductionVacuumgasquenchinginvolvinghighpressuregasasacoolingmedium,is.anincreasinglypoPularheattreatffienttechniquefor1argesteeldieblocks,forexamPleHl3die.ItisconsideredessefltialtounderstandthentheeofthegasflowandtheinfiuencethishasontemPeratureprofilesandresultaflresidualstresseswithintheheattTeatedcomPonent.SimulatingthisprocessinvolvesthesimulationofgasflowinthefurnaceaswellasthesimulationofthethermalbehaviourofthecomPoneni.However,thereisnosinglecomPatersoftwarepackageavailabletot…     

THE EFFECT OF VITAMIN C INTAKE ON GLYCOHEMOGLOBIN MEASUREMENTS

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独柱墩桥梁抗倾覆稳定性分析

以某高速公路立交四跨一联独柱曲线连续箱梁桥为背景,基于《公路钢筋混凝土及预应力混凝土桥涵设计规范》(JTG 3362-2018)对桥梁抗倾覆的相关规定进行研究.利用Midas Civil建立桥梁有限元模型,分析该桥的抗倾覆稳定性,并研究了联端支座间距、中支座外偏心距及温度效应对独柱墩桥梁倾覆稳定性的影响.结果表明,增大联端支座间距、设置合理中支座外偏心距可有效提升桥梁抗倾覆能力;温度效应在独柱墩梁桥抗倾覆设计验算中不可忽视.     

综合物探技术在盾构隧道基岩段的应用

为了查明盾构隧道基岩浅埋段各种不良地质作用的分布特征,通过采用高密度电阻率法、浅层地震折射波法、微动勘探法等综合物探技术,对隧道基岩埋深、断裂破碎带及孤石等异常地质状况进行探测及研究。综合比较三种物探手段,结合钻探、地质调查成果,对复合地层进行有效划分,并对盾构选型设计和施工措施提出针对性建议。     

动态跳跃点火停缸与米勒循环过程组合的节油效果

动态跳跃点火在常规汽油机和电驱动动力总成汽车上已显示出显著降低CO2排放的潜力,与米勒循环等先进技术一起协同配合能获得进一步的节油效果,在动态运行中还能控制废气温度,这对发动机稀薄运行时的废气后处理非常有利.     

特殊用途重载轴承滚子型线参数优选设计研究

一种特殊用途轴承,在使用时存在边缘效应,局部应力较大,使用寿命较低。为此,建立了轴承的详细接触分析有限元模型并进行了验证。采用工程对数凸型对滚子型线参数进行优选设计,用python程序实现滚子节点网格参数自动更新,实现多方案的自动分析。对不同型面修型参数和滚子圆角半径进行了多方案计算,得到了优选方案,避免了边缘效应,并使轴承滚子和内圈应力下降15%以上,效果显著。