Topology optimization of modular structures with multiple assemblies and applications to airborne shelves

This work is devoted to the aeronautical application of topology optimization for modular structures with multiple assemblies that consist of repeated standard modules and optional reinforcements.These kinds of structures are widely used owing to their transportability,reconfigurability,low manufacturing and service costs.In this work,the design of airborne shelves with modular structures characterized by the standard module configuration is formulated for the first time as a topology optimization problem of multiple assemblies and multiple load cases subjected to the volume constraint.It is shown that the weighted compliance design of multiple assemblies is a compromising solution compared to the optimization result of each individual assembly of standard modules.Meanwhile,the performance of optimized airborne shelves with the modular structures can effectively be ameliorated with the help of reinforcements.

Status and trends in the stability of the three largest ice shelves in Antarctica

The Ross,Filchner-Ronne,and Amery ice shelves are the three largest ice shelves in Antarctica,playing a crucial role in supporting the Antarctic ice sheet.However,current studies on the stability of the three largest ice shelves primarily focus on singular or limited factors,lacking a comprehensive assessment of multiple parameters.To systematically and in-depth study the stability and trend of the three largest ice shelves,we comprehensively collected and analyzed key parameters,including elevation changes,basal melting,surface meltwater,major rifts propagation rate,suture zones,ice front area change rate,grounding lines,ice velocity,and mass balance.Additionally,we selected the collapsed Larsen B Ice Shelf(LBIS),the rapidly changing and structurally weakened Pine Island Ice Shelf(PIIS),and the accelerating Totten Ice Shelf(TIS)as reference ice shelves.By comparing and analyzing the key parameters between these reference ice shelves and the three largest ice shelves,we find the status and trends in the stability of the latter.Our findings reveal that most key parameters of the three largest ice shelves present relatively minor variations compared to those of the reference ice shelves.Specifically,50%of the parameters are smaller than those of the accelerating TIS,88%are smaller than those of the rapidly changing PIIS,and all parameters are smaller than those of the collapsed LBIS.Furthermore,after analyzing parameters that are not smaller than those of the TIS,it is observed that they remain in a stable state.Hence,the three largest ice shelves are currently undergoing natural changes that do not threaten their stability in the short term.Nevertheless,the evolution of the ice shelves under global climate change remains uncertain,making long-term observation and monitoring essential to assess their impact on sea level rise.

公共图书馆播客品牌构建与营销策略研究——以多伦多公共图书馆Shelve Under播客品牌为例

播客是互联网时代的产物,自诞生之日起,经历了兴起、萎缩、停滞三个历史阶段,现又逐渐走入复苏时期。大数据技术的持续升级与快餐式阅读消费的广泛流行进一步突显了音频媒介可随性收听的优势,播客平台的发展迎来了新的机遇。文章详细阐述了播客的突出优势、国内发展现状及面临挑战等,对加拿大多伦多公共图书馆播客品牌Shelve Under进行深入挖掘,分析其品牌构建与营销特点,以期给国内公共图书馆创新音频服务提供参考,推动听力资源更好地融入大众的学习和生活。

A Global Perspective on Crustal Structure and Evolution based on A New Crustal Classification

Knowledge of the crustal structure is the key for understanding physical and chemical conditions of its formation and later modification by geodynamic processes.It has long been recognized that crustal structure is controlled by tectonic settings,and that the crustal thickness is one of the most important parameters that reflects the geodynamic origin of the crust.A long tectonic life of continental crust leads to its significant reworking by plate tectonics processes and crust-mantle interaction,which include mechanical extension.

The study of ice shelf-ocean interaction techniques and recent results

Although the importance to global oceanography of ice shelf-oceaaa interactions has been recognized for many years, only more recently has its role in the control of ice flow- from the interior, grounded ice sheet into the ocean been more clearly understood. The consequences for global sea level of increasing ice loss from the Antarctic and Greenland ice sheets has prompted rapidly growing research efforts in this area. Here we describe the different techniques commonly employed in the field study of ice shelf-ocean interactions. We focus on techniques used by the British Antarctic Survey, primarily on Filchner-Ronne Ice Shelf, and describe some recent results from instruments deployed both beneath the ice shelf and on its upper surface, which demonstrate variability at a broad range of time scales.

The Uncertain,or the Shelved...

Duration:July 16,2016 to August 31,2016Location:ShanghART Gallery Main&H Space,BIdg16,18 Moganshan Road,ShanghaiGroup exhibition The uncertain,or the shelved...will be showcased in ShanghART Gallery both Main and H Space on July 16th.The diversified perspectives have been finalised after sourcing through numerous artists’

A comprehensive assessment and analysis of Antarctic satellite grounding line products from 1992 to 2009

In this paper,we present the results of a comprehensive assessment and analysis of five major Antarctic grounding line(GL)products from remote sensing data.The systematic assessment of this large amount of GL data was performed using a new two-step framework and implementation strategy,in which 84.4%of the product data were processed effectively by using a set of developed assessment metrics,with the remaining 15.6%handled by a comprehensive manual processing procedure aided by additional multisource data.The radar GL product shows a high quality(inconsistency of 0.3%)and is recommended for use wherever available.Meanwhile,the optical image GL products show a lower quality(inconsistency of 3-12%)but offer complete coverage,particularly in areas of weak tides.The GL analysis based on the assessed products(1992–2009)showed that 9.5%of the entire Antarctic GL were retreating or advancing,classified as a dynamic state.At the basin scale,the highest retreat rate was−1544±51 m a^(-1) in Basin 22(including Pine Island Glacier)and the highest advancement rate was 304±16 m a^(-1) in Basin 14(including Mertz Glacier).The West Antarctic Ice Sheet(WAIS)and the East Antarctic Ice Sheet(EAIS)showed the average GL change rates of−370±8 m a^(-1) and 5±7 m a^(-1),respectively,indicating that there was a clear trend of GL retreat in WAIS and a balanced to slightly advanced GL state in EAIS(except for the region around Totten).

The Apple of Discord

In the weltering heat and thirst of summer,people who sought to chill with the many seasonal fruits available have received an-other shock.The luscious varieties available on supermarket shelves no longer have the same beautiful prices seen last year.