Reproducible mini-slump test procedure for measuring the yield stress of cementitious pastes

The mini-slump test is a fast, inexpensive and widely adopted method for evaluating the workability of fresh cementitious pastes. However, this method lacks a standardised procedure for its experimental implementation, which is crucial to guarantee reproducibility and reliability of the test results. This study investigates and proposes a guideline procedure for mini-slump testing, focusing on the influence of key experimental (mixing and testing) parameters on the statistical performance of the results. The importance of preparation of always testing at the same time after mixing, testing each batch once rather than conducting multiple tests on a single batch of material, is highlighted. A set of alkali-activated fly ash-slag pastes, spanning from 1 to 75 Pa yield stresses, were used to validate the test method, by comparison of calculated yield stresses with the results obtained using a conventional vane viscometer. The proposed experimental procedure for mini-slump testing produces highly reproducible results, and the yield stress calculated from mini-slump values correlate very well with those measured by viscometer, in the case of fresh paste of pure shear flow. Mini-slump testing is a reliable method that can be utilised for the assessment of workability of cements

Sự thật thơ và đời Hồ Xuân Hương

237 tr.; 19 cm

Sự thật thơ và đời Hồ Xuân Hương

232 tr. ; 19 cm

A Climatology of TC Size and Structure Changes During Extratropical Transition

Dzuy Nguyen; Meteorology; dzuy.d.nguyen‐[email protected]. Faculty mentor: Ben Schenkel; School of Meteorology; [email protected]

Rheology of concentrated bauxite residue suspensions

In the Bayer process where aluminium oxide is extracted from bauxite, a solid residue is generated and accumulated in enormous quantities. A typical alumina refinery may produce 10,000 tonnes per day of dry solid waste, one-third to one-half of which is fine mud, known as red mud, and the remainder is sand-sized materials. The existing disposal method of pumping the residue to settling ponds in the form of a caustic slurry of 20 to 30 percent solids by weight, causes many inherent problems such as high pumping energy consumption, rapid wear in pipelines, inefficient use of available land, and environmental pollution. These problems can be substantially reduced if coarse sands are removed from the residue and the fine red mud is disposed of as a dense slurry at 50 to 60 weight percent solids.Since concentrated mineral suspensions usually exhibit non-Newtonian characteristics, detailed knowledge of the rheology of red mud is essential for design of the pipeline transport system and assessment of energy requirements.<br>[...] <br

Developing a Fake Classifier Node for DIFFUSE

DIFFUSE (Distributed Firewall and Flow-shaper Using Statistical Evidence) is a network prioritisation system which implements Machine-Learning (ML) based techniques to classify and subsequently prioritise flows. Inefficient testing methodologies impacts on future development, making it difficult to upgrade and expand. We have developed a Fake Classifier Node (FCN) that enables manual creation of DIFFUSE messages, bypassing the ML components, leading to more efficient testing and more reliable results. Tests confirm that the FCN is able create DIFFUSE messages and that they are correctly processed by existing DIFFUSE Action Nodes