Cyclic Testing of Reinforced Earthbag Walls

Earthen construction is the most popular building method around the world. One particular building method, using earthbags, has shown promise in performing well against seismic activity. This project undertook the goal of developing a preliminary seismic response modification factor, R, to be used in the design of homes in seismically active areas. Two 4’ wide x 6’ tall x 1’ deep walls were cyclically loaded using a Three-Degree-of-Freedom (TDOF) Test Frame provided by Santa Clara University to determine the in-plane shear capacity of each wall. Testing revealed an average yield force of 419 lbs, an average ultimate force 1058 lbs, and an average R value of 6. Wall design and construction was focused on three aspects of the project that were modeled to replicate common building practices while still being modular enough to test multiple samples. These aspects were the base, bond beam, and wall. Wall bases were designed to withstand up to 3500 lb-ft bending moment during forklift transport, the bond beam was designed to transfer up to 9,000 lbs of shear force into the wall, and, the wall was designed using common building practices used in earthbag construction. Upon completion of the Consortium of Universities for the Research of Earthquake Engineering (CUREE) testing protocol, it was observed that the walls failed in buckling due to compression resulting from the force couple created by the loading arrangement. Despite failure, the walls continued standing even after the pin connection was removed from the tops of wall. This unexpected resiliency and behavior of the walls during testing led the team to believe that earthbag walls are much more ductile a material that was initially anticipated. A deeper understanding is needed to better understand how earthbag buildings behave against seismic forces. This project is encouraging for future research and the development of a more standardized building method

Finding a common story : synthesising findings from two research programs

In this research the authors tackled the issue of synthesising the findings of two independent research programs with common themes into a coherent analysis of teaching and learning across disciplines and school sectors. Through an ongoing dialogue and iterative exploration of emerging themes a synthesis generated new understandings of the use of narrative pedagogies in maths, science and technology, and the aesthetic nature of such learning experiences. This process demonstrates how a comparative lens enables a higher level of analysis of both research programs and generates broader narratives that can be applied to contexts beyond the original research foci

Comparative genomics of Shiga toxin encoding bacteriophages

Background Stx bacteriophages are responsible for driving the dissemination of Stx toxin genes (stx) across their bacterial host range. Lysogens carrying Stx phages can cause severe, lifethreatening disease and Stx toxin is an integral virulence factor. The Stx-bacteriophage vB_EcoP-24B, commonly referred to as 24B, is capable of multiply infecting a single bacterial host cell at a high frequency, with secondary infection increasing the rate at which subsequent bacteriophage infections can occur. This is biologically unusual, therefore determining the genomic content and context of 24B compared to other lambdoid Stx phages is important to understanding the factors controlling this phenomenon and determining whether they occur in other Stx phages. Results The genome of the Stx2 encoding phage, 24B was sequenced and annotated. The genomic organisation and general features are similar to other sequenced Stx bacteriophages induced from Enterohaemorrhagic Escherichia coli (EHEC), however 24B possesses significant regions of heterogeneity, with implications for phage biology and behaviour. The 24B genome was compared to other sequenced Stx phages and the archetypal lambdoid phage, lambda, using the Circos genome comparison tool and a PCR-based multi-loci comparison system. Conclusions The data support the hypothesis that Stx phages are mosaic, and recombination events between the host, phages and their remnants within the same infected bacterial cell will continue to drive the evolution of Stx phage variants and the subsequent dissemination of shigatoxigenic potentia

An extended multiscale principle of virtual velocities approach for evolving microstructure

AbstractA hierarchical multiscale approach is presented for modeling microstructure evolution in heterogeneous materials. Preservation of momentum across each scale transition is incorporated through the application of the principle of virtual velocities at the fine scale giving rise to the appropriate continuum momentum balance equations at the coarse scale. In addition to satisfying momentum balance and invariance of momentum among scales, invariance of elastic free energy, stored free energy, and dissipation between two scales of observation is regarded as crucial to the physics of each scale transition. The preservation of this energy partitioning scheme is obtained through construction of constitutive relations within the framework of internal state variable theory. Internal state variables that are directly computed from the fine scale response are introduced to augment the state equations and describe the inelastic energy storage and dissipation within the fine scale. By virtue of a second gradient kinematic decomposition, the framework naturally gives rise to couple stresses

Pulsed laser deposition for growth of high quality epitaxial garnet films for low threshold waveguide lasers

Pulsed laser deposition (PLD) is a mature technique capable of producing extremely high quality epitaxial single crystalline films. We have grown Nd:doped garnet films of GGG (Gd The talk will summarise our progress using conventional (single beam) PLD in thin-film and waveguide growth, using both nanosecond and femtosecond lasers, and also introduce our new directions in tri-beam PLD (three targets, three lasers) for growth of some interesting, complex and perhaps impossible structures, such as Gaussian doping, internal voids and even helically doped structures

Do Public Transit Investments Promote Urban Economic Development? Evidence from Bogotá, Colombia

In this paper, the authors use a repeated cross-section labor market dataset to assess whether access to the TransMilenio Bus Rapid Transit (BRT) system in Bogotá, Colombia, affects the incomes of those who live in station area neighborhoods. Results indicate that the opening of the system was associated with increased income for those living near – but not immediately adjacent to – trunk line stations. This relationship is strongest in the lower and middle-income range. Two possible explanations for this result are that existing residents earn higher wages, or higher income workers relocate to the neighborhood. While available data do not allow the authors to distinguish clearly between these two causes, evidence suggests that much of the effect is likely due to relocation. The results stand in contrast to prior work, which has largely suggested that improvements in public transit will tend to reduce wages in station areas

Overpressure in the Central North Sea

The Central Graben of the North Sea is characterised by high levels of overpressure. This causes drilling problems and may control the migration and entrapment of hydrocarbons. Pressure measurements from repeat formation tests, mud weight and drilling gas levels have been compiled and interpreted, and integrated with the structural, lithostratigraphic and diagenetic framework of the basin. Interpretation of this data reveals that Jurassic sandstones in the region are divided into a boxwork of pressure cells. These are bodies of rock which are internally in hydraulic communication but externally isolated from adjacent cells by pressure seals. Pressure seals in the region are lithological and vary with depth, in contrast to previous hypotheses of diagenetic or temperature controls. The magnitude of overpressure in a pressure cell is controlled by the structural position of the cell, with high overpressures (close to the lithostatic pressure) occurring in structurally-elevated cells on an axial horst. Lateral hydraulic communication between deep regions and structurally-elevated positions increases the fluid pressure in the permeable sandstones in the elevated regions. This leads to focused vertical fluid flow through the thin aquitard at these elevated regions, which are termed "Leak Points". Here, the pressure seal occurs at the top of the permeable Jurassic sandstone, while in adjacent off-structure regions the pressure seal occurs in the Kimmeridge Clay Fm., the region's petroleum source rock. Analysis of density and sonic log data demonstrates excess mudstone porosity in the overpressured cells, suggesting that disequilibrium compaction is a cause of overpressure in the region. The location of pressure seals within gas-mature source rocks suggests hydrocarbon generation may also play an important role in causing overpressure. Quantitative computer modelling of the basin supports the data-driven model, emphasising lateral flow in Jurassic sandstones beneath the pressure seal and focused vertical flow across formations at structurally-elevated points. The model shows that rapid Cenozoic sedimentation, coupled to low permeability of the mudstone- dominated basin, has led to disequilibrium compaction due to restricted fluid flow. The model suggests that overpressuring began at 40 Ma in Jurassic sandstones of the Graben axis. A link between overpressure-controlled fluid flow and the K-Ar dates of authigenic illite in the Jurassic sandstones is delineated. Measured illite dates coincide with modelled periods of declining fluid flow. A link to the incursion of organic acids from adjacent mudstones into the sandstones is proposed, with the supply of organic acids controlled by the compaction and overpressure in the basin. The distribution of porosity within Jurassic sandstones is examined and is shown to be controlled by the complex distribution of overpressure. Overpressure supports the development of secondary porosity. Products of mineral dissolution are preferentially removed from Leak Points due to enhanced vertical fluid flow. This results in 10-12% excess porosity at 4.6 km depth. Overpressure is a dynamic system, with basin-scale structures such as pressure cells being caused by microscopic changes in pore size. The basin-scale overpressure systems in turn effect pore-scale alterations on the basin. Overpressure is an expression of the complex dynamic interaction of coupled hydrogeological and geochemical processes active throughout the evolution of the basin

Smart Metering Early Learning Project: Synthesis Report

Smart electricity and gas meters with the offer of an in-home display are due to be rolled out to all households in Great Britain by the end of 2020. DECC commissioned this synthesis research as part of its work to support a successful smart metering implementation programme (the Programme), to offer an initial analysis of progress to date and to learn how householders can best be engaged in order to benefit from the roll-out, in particular by saving energy. This report summarises and analyses evidence from a range of sources, including three new DECC research projects into how GB householders engage with smart metering, GB and international evidence on smart metering and energy feedback, and evidence from public health behaviour change programmes