Arch bridges – unlocking their potential

Arch bridges are strong, durable, aesthetically pleasing and require little maintenance but very few have been built since the early 1900s. However, this trend has changed as more than 60 FlexiArch bridges have been installed since the system was launched in 2007. The FlexiArch uses precast concrete voussoirs, requires neither corrodible reinforcement, nor centring, can be installed in hours and is contractor friendly. Details of this innovative method of construction and installation of arch bridges are given and the enormous potential of the system for multi-span viaducts is also highlighted. </jats:p

Adapting the FlexiArch for widening a complex arch bridge

The 1840's Teewell Hill arch bridge, in the suburbs of Bristol, UK, was no longer adequate for increasing local traffic levels and needed to be widened. Several widening options were considered and it was concluded that the innovative ‘FlexiArch’ would best accommodate the complex geometry of the existing structure while minimising social and economic impacts. In order to elegantly accommodate the raked spandrel walls of the existing bridge Macrete and WSP|Parsons Brinckerhoff worked collaboratively to produce a custom-designed, high-quality, precast concrete FlexiArch, which matched the contours of the existing bridge. As the FlexiArch system has no corrodible reinforcement, it is highly sustainable and will result in reduced maintenance, as for the existing bridge. The elimination of centring and speed of construction (hours not months) minimised disruption to road traffic and to cyclists on the cycle network below the bridge – a key project criterion required by the client. Thus, in addition to addressing an accident black spot, the FlexiArch solution provided South Gloucestershire Council (the client) with an aesthetically pleasing and fully functional solution at a competitive cost

The dragon awakens: innovation, competition, and transition in the energy strategy of the People’s Republic of China, 1949-2017

Based on a mix of original archival research and an extensive review of the contemporary peer reviewed literature, this article reviews the history of the People’s Republic of China’s national energy policies since 1949. We divide this history into six phases: Emergence (1949–1957), Socialist construction (1958–1965), Turbulence (1966–1978), Reform (1979–2000), Contestation (2001–2014), and transition (2015-present). Over the whole history of more than sixty years, China’s energy production and consumption grew at a surprising speed, while energy intensity exhibited early fluctuations and a subsequent gradual decrease after the turbulence phase. In tracing this history, the article offers new historical and policy insights into the world’s largest developing country and a theoretical contribution to the role of the state in shaping economy and society through energy policy. The article lastly offers an in-depth exploration of how command-and-control style administrative intervention and low levels of market liquidity have had a prophylactic effect on innovation and competition

Methylamine Separations Enabled by Cooperative Ligand Insertion in Copper–Carboxylate Metal–Organic Frameworks

Monomethylamine (NH2CH3), dimethylamine (NH(CH3)2), and trimethylamine (N(CH3)3) are important chemical feedstocks that are produced industrially as an azeotropic mixture and must be separated using an energy-intensive thermal distillation. While solid adsorbents have been proposed as alternatives to distillation for separating various industrial gas mixtures, methylamine separations remain largely unexplored in this context. Here, we investigate two isoreticular frameworks Cu(cyhdc) (cyhdc2- = trans-1,4-cyclohexanedicarboxylate) and Cu(bdc) (bdc2- = 1,4-benzenedicarboxylate) as prospective candidates for this challenging separation, motivated by the recent discovery that Cu(cyhdc) reversibly captures ammonia through a unique framework-to-coordination polymer phase change. Through a combination of gas adsorption and powder X-ray diffraction analyses, we find that Cu(cyhdc) and Cu(bdc) reversibly bind large quantities of mono- and dimethylamine through framework-to-coordination polymer phase change mechanisms, although both frameworks adsorb only moderate amounts of trimethylamine via physisorption. Single-crystal X-ray diffraction analysis of select mono- and dimethylamine containing phases suggests that the number of hydrogen bond donors available and the linker donor strength are key factors influencing amine uptake. Finally, investigation of the tricomponent adsorption behavior of both materials reveals that Cu(cyhdc) is selective for the capture of monomethylamine from a range of mono-, di-, and trimethylamine mixtures

A graphic method for depicting horizontal direction data on vertical outcrop photographs

Outcrop photographs which show two-dimensional representations of three-dimensionally dipping surfaces (e.g., bedding planes, cross-bed foresets) are commonly utilized in the description of sedimentary strata. In many instances, accurate depiction of the dip direction of such features is paramount for understanding their interpretation, and for visualizing the true form of three-dimensional bodies (e.g., conceptualizing the form of an architectural element in a cliff-face, preserved as a vertical slice that has been cut oblique to paleocurrent direction). However, as an outcrop photograph often presents information on a vertical plane and directional data refers to a horizontal plane, the accurate co-depiction of both sets of information may be challenging. There is presently no universal method for illustrating such measurements on outcrop photographs: techniques in common usage are often imprecise, and the lack of uniformity hinders comparison between different images. Here we present a method for accurately depicting horizontal direction data on vertical outcrop photographs which permits instant visualization of dip relative to the illustrated outcrop geometry. The method is simple to apply, does not compromise primary data, and is unobtrusive to other visual information within images; thus having utility across a broad spectrum of geological investigations

The cyclin-dependent kinase inhibitor Orysa;KRP1 plays an important role in seed development of rice

Kip-related proteins (KRPs) play a major role in the regulation of the plant cell cycle. We report the identification of five putative rice (Oryza sativa) proteins that share characteristic motifs with previously described plant KRPs. To investigate the function of KRPs in rice development, we generated transgenic plants overexpressing the Orysa; KRP1 gene. Phenotypic analysis revealed that overexpressed KRP1 reduced cell production during leaf development. The reduced cell production in the leaf meristem was partly compensated by an increased cell size, demonstrating the existence of a compensatory mechanism in monocot species by which growth rate is less reduced than cell production, through cell expansion. Furthermore, Orysa; KRP1 overexpression dramatically reduced seed filling. Sectioning through the overexpressed KRP1 seeds showed that KRP overproduction disturbed the production of endosperm cells. The decrease in the number of fully formed seeds was accompanied by a drop in the endoreduplication of endosperm cells, pointing toward a role of KRP1 in connecting endocycle with endosperm development. Also, spatial and temporal transcript detection in developing seeds suggests that Orysa; KRP1 plays an important role in the exit from the mitotic cell cycle during rice grain formation