1,245 research outputs found
The effect of using fluid catalytic cracking catalyst residue (FC3R) "as a cement replacement in soft soil stabilisation"
Construction sector suffer from many problems due to presence of the soft soil in many worlds' parts and to solve these problem the soft soil should be stabilised by either mechanically or chemically; the mechanical ways can be achieved by replacing with stronger materials or using special machines to increase the soil stability result which considered high cost, researchers try to find another method with alternative materials like cement, lime and pozzolanic materials to qualify the soft soil on the civil engineering project. The aim of this study is to evaluate the soft soil properties that cured with 9% binders of various mixtures of binary blended produced from Ordinary Portland cement (OPC) and Fluid catalytic cracking catalyst residue (FC3R), which is a by-produced material from petroleum sector. Geotechnical tests like (compaction, un-confined compressive strength (UCS) test and Scanning electron microscopy (SEM)) were used to investigate the optimum binary mixture. Results show that the use of FC3R as a cement replacement developed the strength of soft soil after 28 days result in a higher strength comparison to using OPC alone in soil stabilisation. SEM proved presence of OPC hydration products during different curing ages. © IAEME Publication
Analytical investigation of hydration mechanism of a non-Portland binder with waste paper sludge ash
The development and production of new materials requires advanced analytical characterisation to explain the relation between the physico-chemical structure of the material and its properties. Highly integrated microelectronic structure analysis of surfaces with laser beams and X-ray fluorescence aided devices are found to be helpful for providing important information, including the interrelationships between physical, chemical, mechanical and durability characteristics of the new developed products. In most instances no single technique provides all the needed information and hence simultaneous application of several techniques becomes necessary. This study was aimed for hydration analysis, characterization and evaluation of a new novel non-Portland binder (NPB) with waste paper sludge ash (PSA) using FTIR and TG/DTA. The progressive formation of hydration products within the non-Portland binder was identified and their microstructural characteristics were analysed. The stable and non-expansive nature of secondary ettringite formation was also identified after a period of 365 days curing
Mechanism, dynamics, and biological existence of multistability in a large class of bursting neurons
Multistability, the coexistence of multiple attractors in a dynamical system,
is explored in bursting nerve cells. A modeling study is performed to show that
a large class of bursting systems, as defined by a shared topology when
represented as dynamical systems, is inherently suited to support
multistability. We derive the bifurcation structure and parametric trends
leading to multistability in these systems. Evidence for the existence of
multirhythmic behavior in neurons of the aquatic mollusc Aplysia californica
that is consistent with our proposed mechanism is presented. Although these
experimental results are preliminary, they indicate that single neurons may be
capable of dynamically storing information for longer time scales than
typically attributed to nonsynaptic mechanisms.Comment: 24 pages, 8 figure
Upscaling of solar induced chlorophyll fluorescence from leaf to canopy using the DART model and a realistic 3D forest scene
Non peer reviewe
Poincare Semigroup Symmetry as an Emergent Property of Unstable Systems
The notion that elementary systems correspond to irreducible representations
of the Poincare group is the starting point for this paper, which then goes on
to discuss how a semigroup for the time evolution of unstable states and
resonances could emerge from the underlying Poincare symmetry. Important tools
in this analysis are the Clebsch-Gordan coefficients for the Poincare group.Comment: 17 pages, 1 figur
Power-Based Droop Control in DC Microgrids Enabling Seamless Disconnection From Upstream Grids
This paper proposes a local power-based droop controller for distributed energy resource converters in dc microgrids that are connected to upstream grids by grid-interface converters. During normal operation, the grid-interface converter imposes the microgrid bus voltage, and the proposed controller allows power flow regulation at distributed energy resource converters\u2019 output. On the other hand, during abnormal operation of the grid-interface converter (e.g., due to faults in the upstream grid), the proposed controller allows bus voltage regulation by droop control. Notably, the controller can autonomously convert from power flow control to droop control, without any need of bus voltage variation detection schemes or communication with other microgrid components, which enables seamless transitions between these two modes of operation. Considering distributed energy resource converters employing the power-based droop control, the operation modes of a single converter and of the whole microgrid are defined and investigated herein. The controller design is also introduced. Furthermore, the power sharing performance of this control approach is analyzed and compared with that of classical droop control. The experimental results from a laboratory-scale dc microgrid prototype are reported to show the final performances of the proposed power-based droop control
Social inclusion and valued roles : a supportive framework
The aim of this paper is to examine the concepts of social exclusion, social inclusion and their relevance to health, well-being and valued social roles. The article presents a framework, based on Social Role Valorization (SRV), which was developed initially to support and sustain socially valued roles for those who are, or are at risk of, being devalued within our society. The framework incorporates these principles and can be used by health professionals across a range of practice, as a legitimate starting point from which to support the acquisition of socially valued roles which are integral to inclusio
The development of a low carbon binder produced from the ternary blending of cement, ground granulated blast furnace slag and high calcium fly ash: An experimental and statistical approach
This research aims to develop a new, environmentally friendly, cementitious material by blending Ordinary Portland Cement (OPC), Ground Granulated Blast Furnace Slag (GGBS) and High Calcium Fly Ash (HCFA). Compressive strength and electrical resistivity tests were used to evaluate the mortars’ performance. A multi-regression (MR) model was also utilised to study the effects of curing time and content of OPC, GGBS and HCFA on the mortars’ strength and to identify the relationship between measured and predicted compressive strengths. The results indicated that the newly developed binder was composed of 35 wt% OPC, 35 wt% GGBS and 30 wt% HCFA that showed a compressive strength and surface electrical resistivity of 30.8 MPa and 103.5 kΩ.cm after 56 days of curing, respectively. Significant changes in the microstructure of the developed binder paste over curing time were evidenced by SEM imaging. The statistical analysis indicated that the influence of the parameters examined on the development of the mortars’ compressive strength could be modelled with a coefficient of determination, R2of 0.893, and that the relative importance of these parameters followed the order curing time (t) > HCFA% > OPC% > GGBS%. This new binder could contribute significantly to decreasing the cost of construction materials and to reducing CO2emissions. © 2018 Elsevier Lt
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