Experimental investigation on the dynamic response of RC flat slabs after a sudden column loss

To prevent disproportionate collapse under an extreme loading event, a sudden column loss scenario is often used to ensure the structure has suitable robustness. This study aims to investigate experimentally the dynamic response of reinforced concrete flat slabs after a sudden column loss. Seven 1/3 scale reinforced concrete flat slabs were tested under static load increases or dynamic column removal cases with different supports removed. Reaction forces and deflections were recorded throughout, along with reinforcement strains and concrete cracking patterns. During dynamic tests, a high speed camera was used to capture the dynamic motion. The experiments demonstrated that flat slabs, in general, are able to redistribute their loading effectively after a column loss. Although large levels of damage were observed, collapse due to flexural failure did not occur. However, punching shear was shown to be an issue due to the additional vertical loading on the adjacent supports. The inclusion of continuous bottom reinforcement through a column did not significantly improve the capacity, as the new load path is not primarily through the removed column location. The results also indicate that the dynamic effects due to a sudden column loss can be significant as deflections of up to 1.5 times the static case were measured within the elastic range. It is also shown that the Dynamic Amplification Factor (DAF) reduces when nonlinear damaging effects are included, which implies conventional code-based design methods for flat slab structures may be over conservative. Additionally, the increase in material strength due the strain rates is not viewed to be significant

Dynamic column loss analysis of reinforced concrete flat slabs

The sudden column loss idealisation is a useful design tool to assess structures for progressive collapse. As such an event is a dynamic problem, suitable account must be taken of these effects. This can either be achieved by a full dynamic analysis of the structure or a simplified static approach, with correction factors for the dynamic influence. This study aims to investigate the response of Reinforced Concrete (RC) flat slab structures after a column loss using experimentally validated Finite Element (FE) models. The nonlinear dynamic response of a structure after such an event is considered, including the redistribution of loads and displacement profile. These results are then compared to equivalent static cases in order to determine the Dynamic Amplification Factor (DAF). For the range of structures considered, the DAF was calculated as between 1.39 and 1.62 for displacements, with lower factors associated with a higher nonlinear response or slower column removal. Additionally, the shear forces in remaining columns may exceed 200% of their fully supported condition, with a different associated DAF. The effects of increasing the tensile strength of concrete due to high strain rates are also considered. Typical Dynamic Increase Factors (DIFs) based on the strain rates were up to 1.23, however, this only applied for a short time period, and in a limited area. Therefore, such effects do not significantly influence the response

Constitutive modelling of Sandvik 1RK91

A physically based constitutive equation is being developed for the maraging\ud stainless steel Sandvik 1RK91. The steel is used to make precision parts. These parts are formed through multistage forming operations and heat treatments from cold rolled and annealed sheets. The specific alloy is designed to be thermodynamically unstable, so that deformation even at room temperatures can bring about a change in the phase of face centred cubic austenite to either hexagonal closed packed martensite and/or, body centred cubic martensite. This solid state phase change is a function of the strain path, strain, strain rate and temperature. Thus, the fraction of the new phase formed depends on the state of stress at a given location in the part being formed. Therefore a set of experiments is being conducted in order to quantify the stress-strain behavior of this steel under various stress states, strain, strain rate as well as temperature. A magnetic sensor records the fraction of ferromagnetic martensite formed from paramagnetic austenite. A thermocouple as well as an infra red thermometer is used to log the change in temperature of the steel during a mechanical test. The force-displacement data are converted to stress-strain data after correcting for the changes in strain rate and temperature. These data are then cast into a general form of constitutive equation and the transformation equations are derived from Olson-Cohen type functions

High Power Cyclotrons for the Neutrino Experiments DAEδALUS and IsoDAR

DAEδALUS (Decay At rest Experiment for δcp At a Laboratory for Underground Science) has been proposed to measure the value of the CP violating phase delta through the oscillation of low energy muon anti-neutrinos to electron antineutrinos. With a single large detector, three accelerators at different distances enable the oscillation to be measured with sufficient accuracy. We have proposed the superconducting multi-megawatt DAEδALUS Supercinducting Ring Cyclotron (DSRC) as the means of producing the 800 MeV 12 mA protons required, through the acceleration of H2+, ions with highly efficient stripping extraction. The DSRC comprises twin ion sources and injector cyclotrons, followed by a booster. The injector cyclotron can also be used for a separate experiment, IsoDAR (Isotope Decay At Rest) in which low energy protons produce Lithium 8, and thus a very pure electron antineutrino source which can be used to measure, or rule out, short range oscillation to a sterile neutrino. We describe recent developments in the designs of the injector and the booster, and the prospects for the two experiments

Ipsilateral breast tumour relapse: local recurrence versus new primary and the effect of whole breast radiotherapy on the rate of new primaries

PurposeThe justification for partial breast radiotherapy after breast conservation surgery assumes that ipsilateral breast tumor relapses (IBTR) outside the index quadrant are mostly new primary (NP) tumors that develop despite radiotherapy. We tested the hypothesis that whole-breast radiotherapy (WBRT) is ineffective in preventing NP by comparing development rates in irradiated and contralateral breasts after tumor excision and WBRT.Methods and MaterialsWe retrospectively reviewed 1,410 women with breast cancer who were entered into a prospective randomized trial of radiotherapy fractionation and monitored annually for ipsilateral breast tumor relapses (IBTR) and contralateral breast cancer (CLBC). Cases of IBTR were classified into local recurrence (LR) or NP tumors based on location and histology and were subdivided as definite or likely depending on clinical data. Rates of ipsilateral NP and CLBC were compared over a 15-year period of follow-up.ResultsAt a median follow-up of 10.1 years, there were 150 documented cases of IBTR: 118 (79%) cases were definite or likely LR; 27 (18%) cases were definite or likely NP; and 5 (3%) cases could not be classified. There were 71 cases of CLBC. The crude proportion of definite-plus-likely NP was 1.9% (27/1,410) patients compared with 5% (71/1,410) CLBC patients. Cumulative incidence rates at 5, 10, and 15 years were 0.8%, 2.0%, and 3.5%, respectively, for definite-plus-likely NP and 2.4%, 5.8%, and 7.9%, respectively for CLBC, suggesting a difference in the rates of NP and CLBC.ConclusionsThis analysis suggests that WBRT reduces the rate of ipsilateral NP tumors. The late presentation of NP has implications for the reporting of trials that are testing partial breast radiotherapy

SUMOylation Is Required for Glycine-Induced Increases in AMPA Receptor Surface Expression (ChemLTP) in Hippocampal Neurons

yesMultiple pathways participate in the AMPA receptor trafficking that underlies long-term potentiation (LTP) of synaptic transmission. Here we demonstrate that protein SUMOylation is required for insertion of the GluA1 AMPAR subunit following transient glycine-evoked increase in AMPA receptor surface expression (ChemLTP) in dispersed neuronal cultures. ChemLTP increases co-localisation of SUMO-1 and the SUMO conjugating enzyme Ubc9 and with PSD95 consistent with the recruitment of SUMOylated proteins to dendritic spines. In addition, we show that ChemLTP increases dendritic levels of SUMO-1 and Ubc9 mRNA. Consistent with activity dependent translocation of these mRNAs to sites near synapses, levels of the mRNA binding and dendritic transport protein CPEB are also increased by ChemLTP. Importantly, reducing the extent of substrate protein SUMOylation by overexpressing the deSUMOylating enzyme SENP-1 or inhibiting SUMOylation by expressing dominant negative Ubc9 prevent the ChemLTP-induced increase in both AMPAR surface expression and dendritic SUMO-1 mRNA. Taken together these data demonstrate that SUMOylation of synaptic protein(s) involved in AMPA receptor trafficking is necessary for activity-dependent increases in AMPAR surface expression.Medical Research Council, the European Research Council and the Wellcome Trus

The emergence of integrated information, complexity, and \u27consciousness\u27 at criticality

© 2020 by the authors. Integrated Information Theory (IIT) posits that integrated information (F) represents the quantity of a conscious experience. Here, the generalized Ising model was used to calculate F as a function of temperature in toy models of fully connected neural networks. A Monte-Carlo simulation was run on 159 normalized, random, positively weighted networks analogous to small five-node excitatory neural network motifs. Integrated information generated by this sample of small Ising models was measured across model parameter spaces. It was observed that integrated information, as an order parameter, underwent a phase transition at the critical point in the model. This critical point was demarcated by the peak of the generalized susceptibility (or variance in configuration due to temperature) of integrated information. At this critical point, integrated information was maximally receptive and responsive to perturbations of its own states. The results of this study provide evidence that F can capture integrated information in an empirical dataset, and display critical behavior acting as an order parameter from the generalized Ising model

TGFβ inhibition stimulates collagen maturation to enhance bone repair and fracture resistance in a murine myeloma model

Multiple myeloma is a plasma cell malignancy that causes debilitating bone disease and fractures, in which TGFβ plays a central role. Current treatments do not repair existing damage and fractures remain a common occurrence. We developed a novel low tumour phase murine model mimicking the plateau phase in patients, as we hypothesized this would be an ideal time to treat with a bone anabolic. Using in vivo microCT we show substantial and rapid bone lesion repair (and prevention) driven by SD‐208 (TGFβ receptor I kinase inhibitor) and chemotherapy (bortezomib and lenalidomide) in mice with human U266‐GFP‐luc myeloma. We discovered that lesion repair occurred via an intramembranous fracture repair‐like mechanism and that SD‐208 enhanced collagen matrix maturation to significantly improve fracture resistance. Lesion healing was associated with VEGFA expression in woven bone, reduced osteocyte‐derived PTHrP, increased osteoblasts, decreased osteoclasts and lower serum TRACP‐5b. SD‐208 also completely prevented bone lesion development mice with aggressive JJN3 tumors, and was more effective than an anti‐TGFβ neutralizing antibody (1D11). We also discovered that SD‐208 promoted osteoblastic differentiation (and overcame the TGFβ‐induced block in osteoblastogenesis) in myeloma patient bone marrow stromal cells in vitro, comparable to normal donors. The improved bone quality and fracture‐resistance with SD‐208 provides incentive for clinical translation to improve myeloma patient quality of life by reducing fracture risk and fatality

Citizen science for policy formulation and implementation

Citizen science, the active participation of the public in scientific research projects, is a rapidly expanding field in open science and open innovation. It provides an integrated model of public knowledge production and engagement with science. As a growing worldwide phenomenon, it is invigorated by evolving new technologies that connect people easily and effectively with the scientific community. Catalysed by citizens’ wishes to be actively involved in scientific processes, as a result of recent societal trends, it also offers contributions to the rise in tertiary education. In addition, citizen science provides a valuable tool for citizens to play a more active role in sustainable development. This book identifies and explains the role of citizen science within innovation in science and society, and as a vibrant and productive science-policy interface. The scope of this volume is global, geared towards identifying solutions and lessons to be applied across science, practice and policy. The chapters consider the role of citizen science in the context of the wider agenda of open science and open innovation, and discuss progress towards responsible research and innovation, two of the most critical aspects of science today