Vibration characteristics of a deployable controllable-geometry truss boom

An analytical study was made to evaluate changes in the fundamental frequency of a two dimensional cantilevered truss boom at various stages of deployment. The truss could be axially deployed or retracted and undergo a variety of controlled geometry changes by shortening or lengthening the telescoping diagonal members in each bay. Both untapered and tapered versions of the truss boom were modeled and analyzed by using the finite element method. Large reductions in fundamental frequency occurred for both the untapered and tapered trusses when they were uniformly retracted or maneuvered laterally from their fully deployed position. These frequency reductions can be minimized, however, if truss geometries are selected which maintain cantilever root stiffness during truss maneuvers

Dynamic characteristics of a space-station solar wing array

A solar-wing-array concept is described which meets space-station requirements for minimum fundamental frequency (0.4 Hz), component modularity, and growth potential. The basic wing-array design parameters are varied, and the resulting effects on the array vibration frequencies and mode shapes are assessed. The transient response of a free-free space station (incorporating a solar-wing-array point design) to a load applied at the space-station center is studied. The use of the transient response studies in identifying critically loaded structural members is briefly discussed. The final 150-kW space-station configuration has a fundamental elastic frequency of 0.403 Hz

Kinetics of running on arboreal versus terrestrial substrates in Siberian chipmunks

Many mammals travel on both tree branches and flat ground in their natural habitat. Forelimbs were found to have the dominant role in braking on both substrates, while hindlimbs had the dominant role in propulsion on both substrates. However, the forelimb aided in propulsion more so than the hindlimbs contributed to braking on both substrates.https://engagedscholarship.csuohio.edu/u_poster_2012/1013/thumbnail.jp

The Emerging New World Order\u27s Alarm Bells: Men Like Brandon Tarrant and Andreas Breivik

This week\u27s attack on two mosques in New Zealand reflects a paradigm shift: the erosion of liberal values and the rise of civilisationalism at the expense of the nation-state. So do broader phenomena like widespread Islamophobia with the crackdown on Turkic Muslims in Xinjiang as its extreme, and growing ant-Semitism These phenomena are fuelled by increasing intolerance and racism enabled by far right and world leaders as well as ultra-conservatives and jihadists.   These world leaders and far-right ideologues couch their policies and views in terms of defending a civilization rather than exclusively a nation-state defined by its citizenry and borders

Middle Eastern Protests Challenge Debilitating Gulf Counterrevolution

Much of the Middle East's recent turmoil stems from internecine Middle Eastern rivalries spilling onto third country battlefields and Saudi and United Arab Emirates-led efforts to roll back the achievements of the 2011 popular Arab revolts and pre-empt further uprisings.   This week's successful toppling of ailing Algerian president Abdelaziz Bouteflika and months of anti-government demonstrations that have put Sudanese leader Omar al-Bashir on the defensive suggest that the Saudi-UAE effort may be faltering

Turkic Chinese Soup: a Barometer of Anti-Chinese Sentiment

A heavy soup made of pulled noodles, meat, and vegetables symbolizes Central Asia's close cultural and/or ethnic ties with China's repressed Turkic and Hui Muslims. It also explains growing Central Asian unease with China's re-education campaign in its north-western province of Xinjiang and its signature infrastructure and energy driven-Belt and Road initiative

Turkish-Chinese Spat Puts Central Asian Leaders on the Spot

A Turkish-Chinese spat as a result of Turkish criticism of China's crackdown on Turkic Muslims in its strategic but troubled north-western province of Xinjiang complicates efforts by Kazakhstan and other Central Asian states to at best deal quietly behind closed doors with the plight of their citizens and ethnic kin in the People's Republic.   China's threat that the Turkish criticism of its massive surveillance and detention campaign, involving the alleged incarceration in re-education camps of up to one million Uyghurs and other Turkic Muslims would have economic consequences and the temporary closure of the Chinese consulate in the Mediterranean port city of Izmir serves as warnings to others in the Muslim world what could happen if they break their silence