scholarly journals A Step by Step Methodology for Building Sustainable Cementitious Matrices

2020 ◽  
Vol 10 (8) ◽  
pp. 2955 ◽  
Author(s):  
Styliani Papatzani ◽  
Kevin Paine
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Silica Fume ◽  
Carbon Footprint ◽  
State Of The Art ◽  
Cost Effective ◽  
Strength Development ◽  
Low Carbon ◽  
Current State ◽  
First Time

In an effort to produce cost-effective and environmentally friendly cementitious binders. mainly ternary (Portland cement + limestone + pozzolanas) formulations have been investigated so far. Various proportions of constituents have been suggested, all, however, employing typical Portland cement (PC) substitution rates, as prescribed by the current codes. With the current paper a step by step methodology on developing low carbon footprint binary, ternary and quaternary cementitious binders is presented (PC replacement up to 57%). Best performing binary (60% PC and 40% LS (limestone)) and ternary formulations (60% PC, 20% LS, 20% FA (fly ash) or 43% PC, 20% LS 37% FA) were selected on the grounds of sustainability and strength development and were further optimized with the addition of silica fume. For the first time a protocol for successfully selecting and testing binders was discussed and the combined effect of highly pozzolanic constituents in low PC content formulations was assessed and a number of successful matrices were recommended. The present paper enriched the current state of the art in composite low carbon footprint cementitious binders and can serve as a basis for further enhancements by other researchers in the field.

COMPRESSIVE STRENGTH AND THERMAL CONDUCTIVITY OF WATER AND AIR CURED PORTLAND CEMENT-FLY ASH-SILICA FUME MORTARS

2018 ◽  
Vol 17 (9) ◽  
pp. 2023-2030
Author(s):  
Arnon Chaipanich ◽  
Chalermphan Narattha ◽  
Watcharapong Wongkeo ◽  
Pailyn Thongsanitgarn
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Fly Ash ◽  
Portland Cement ◽  
Silica Fume

scholarly journals Electro-Quasistatic Animal Body Communication for Untethered Rodent Biopotential Recording

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shreeya Sriram ◽  
Shitij Avlani ◽  
Matthew P. Ward ◽  
Shreyas Sen
Keyword(s):  
Lower Energy ◽  
Sensor Node ◽  
State Of The Art ◽  
The Body ◽  
Animal Body ◽  
Current State ◽  
Communication Modalities ◽  
First Time ◽  
Biopotential Recording

AbstractContinuous multi-channel monitoring of biopotential signals is vital in understanding the body as a whole, facilitating accurate models and predictions in neural research. The current state of the art in wireless technologies for untethered biopotential recordings rely on radiative electromagnetic (EM) fields. In such transmissions, only a small fraction of this energy is received since the EM fields are widely radiated resulting in lossy inefficient systems. Using the body as a communication medium (similar to a ’wire’) allows for the containment of the energy within the body, yielding order(s) of magnitude lower energy than radiative EM communication. In this work, we introduce Animal Body Communication (ABC), which utilizes the concept of using the body as a medium into the domain of untethered animal biopotential recording. This work, for the first time, develops the theory and models for animal body communication circuitry and channel loss. Using this theoretical model, a sub-inch$$^3$$ 3 [1″ × 1″ × 0.4″], custom-designed sensor node is built using off the shelf components which is capable of sensing and transmitting biopotential signals, through the body of the rat at significantly lower powers compared to traditional wireless transmissions. In-vivo experimental analysis proves that ABC successfully transmits acquired electrocardiogram (EKG) signals through the body with correlation $$>99\%$$ > 99 % when compared to traditional wireless communication modalities, with a 50$$\times$$ × reduction in power consumption.

scholarly journals Strength Development and Elemental Distribution of Dolomite/Fly Ash Geopolymer Composite under Elevated Temperature

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 1015 ◽  
Author(s):  
Emy Aizat Azimi ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Petrica Vizureanu ◽  
Mohd Arif Anuar Mohd Salleh ◽  
Andrei Victor Sandu ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Fly Ash ◽  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Raw Materials ◽  
Liquid Sodium ◽  
Strength Development ◽  
Elemental Distribution ◽  
Distribution Analysis ◽  
Geopolymer Composites

A geopolymer has been reckoned as a rising technology with huge potential for application across the globe. Dolomite refers to a material that can be used raw in producing geopolymers. Nevertheless, dolomite has slow strength development due to its low reactivity as a geopolymer. In this study, dolomite/fly ash (DFA) geopolymer composites were produced with dolomite, fly ash, sodium hydroxide, and liquid sodium silicate. A compression test was carried out on DFA geopolymers to determine the strength of the composite, while a synchrotron Micro-Xray Fluorescence (Micro-XRF) test was performed to assess the elemental distribution in the geopolymer composite. The temperature applied in this study generated promising properties of DFA geopolymers, especially in strength, which displayed increments up to 74.48 MPa as the optimum value. Heat seemed to enhance the strength development of DFA geopolymer composites. The elemental distribution analysis revealed exceptional outcomes for the composites, particularly exposure up to 400 °C, which signified the homogeneity of the DFA composites. Temperatures exceeding 400 °C accelerated the strength development, thus increasing the strength of the DFA composites. This appears to be unique because the strength of ordinary Portland Cement (OPC) and other geopolymers composed of other raw materials is typically either maintained or decreases due to increased heat.

Mössbauer, DTA and XRD study of Portland cement blended with fly ash and silica fume

2012 ◽  
Vol 29 ◽  
pp. 33-41 ◽  
Author(s):  
Vili Lilkov ◽  
Ognyan Petrov ◽  
Yana Tzvetanova ◽  
Plamen Savov
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Silica Fume ◽  
Xrd Study

scholarly journals Using plants to remediate or manage metal-polluted soils: an overview on the current state of phytotechnologies

2021 ◽  
Vol 43 ◽  
pp. e58283
Author(s):  
Clístenes Williams Araújo do Nascimento ◽  
Caroline Miranda Biondi ◽  
Fernando Bruno Vieira da Silva ◽  
Luiz Henrique Vieira Lima
Keyword(s):  
Large Scale ◽  
State Of The Art ◽  
Cost Effective ◽  
Time Frame ◽  
Contaminated Site ◽  
Polluted Soils ◽  
Mining Sites ◽  
Current State ◽  
Remedial Actions ◽  
The Tropics

Soil contamination by metals threatens both the environment and human health and hence requires remedial actions. The conventional approach of removing polluted soils and replacing them with clean soils (excavation) is very costly for low-value sites and not feasible on a large scale. In this scenario, phytoremediation emerged as a promising cost-effective and environmentally-friendly technology to render metals less bioavailable (phytostabilization) or clean up metal-polluted soils (phytoextraction). Phytostabilization has demonstrable successes in mining sites and brownfields. On the other hand, phytoextraction still has few examples of successful applications. Either by using hyperaccumulating plants or high biomass plants induced to accumulate metals through chelator addition to the soil, major phytoextraction bottlenecks remain, mainly the extended time frame to remediation and lack of revenue from the land during the process. Due to these drawbacks, phytomanagement has been proposed to provide economic, environmental, and social benefits until the contaminated site returns to productive usage. Here, we review the evolution, promises, and limitations of these phytotechnologies. Despite the lack of commercial phytoextraction operations, there have been significant advances in understanding phytotechnologies' main constraints. Further investigation on new plant species, especially in the tropics, and soil amendments can potentially provide the basis to transform phytoextraction into an operational metal clean-up technology in the future. However, at the current state of the art, phytotechnology is moving the focus from remediation technologies to pollution attenuation and palliative cares.

Microstructure of Cement Blends Including Fly Ash, Silica Fume, Slag and Fillers

1986 ◽  
Vol 86 ◽  
Author(s):  
Micheline Regourd
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Silica Fume ◽  
Blended Cement ◽  
Cement Clinker ◽  
Microstructural Development ◽  
Limestone Filler ◽  
Portland Cement Clinker

ABSTRACTThe hydration of a blended cement through hydraulic or pozzolanic reactions results in heterogeneous polyphase materials. Because portland cement clinker is the major component in most cement blends, the microstructural development of portland cement hydrates, including C-S-H and pore structures, is first discussed. Slag, fly ash, silica fume and limestone filler cements are then compared to portland cement with regards to C-S-H morphology and composition, aluminate crystallization, cement paste interfaces and pore size distribution.

High Performance Concrete with Ternary Binders

2018 ◽  
Vol 761 ◽  
pp. 120-123 ◽  
Author(s):  
Vlastimil Bílek ◽  
David Pytlík ◽  
Marketa Bambuchova
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Silica Fume ◽  
High Performance ◽  
Ordinary Portland Cement ◽  
High Performance Concrete ◽  
Fresh Concrete ◽  
Binder Ratio ◽  
Water To Binder Ratio ◽  
Condensed Silica Fume

Use a ternary binder for production of a high performance concrete with a compressive strengths between 120 and 170 MPa is presented. The water to binder ratio of the concrete is 0.225 and the binder is composed of Ordinary Portland Cement (OPC), condensed silica fume (CSF), ground limestone (L), fly ash (FA) and metakaoline (MK). The dosage of (M + CSF) is kept at a constant level for a better workability of fresh concrete. Different workability, flexural and compressive strengths were obtained for concretes with a constant cement and a metakaoline dosage, and for a constant dosage (FA + L) but a different ratio FA / L. An optimum composition was found and concretes for other tests were designed using this composition.

scholarly journals Regularized Evolution for Image Classifier Architecture Search

2019 ◽  
Vol 33 ◽  
pp. 4780-4789 ◽  
Author(s):  
Esteban Real ◽  
Alok Aggarwal ◽  
Yanping Huang ◽  
Quoc V. Le
Keyword(s):  
Neural Network ◽  
Learning Algorithm ◽  
State Of The Art ◽  
Simple Method ◽  
Current State ◽  
Network Topologies ◽  
Comparable Accuracy ◽  
Tournament Selection ◽  
Complex Architecture ◽  
First Time

The effort devoted to hand-crafting neural network image classifiers has motivated the use of architecture search to discover them automatically. Although evolutionary algorithms have been repeatedly applied to neural network topologies, the image classifiers thus discovered have remained inferior to human-crafted ones. Here, we evolve an image classifier— AmoebaNet-A—that surpasses hand-designs for the first time. To do this, we modify the tournament selection evolutionary algorithm by introducing an age property to favor the younger genotypes. Matching size, AmoebaNet-A has comparable accuracy to current state-of-the-art ImageNet models discovered with more complex architecture-search methods. Scaled to larger size, AmoebaNet-A sets a new state-of-theart 83.9% top-1 / 96.6% top-5 ImageNet accuracy. In a controlled comparison against a well known reinforcement learning algorithm, we give evidence that evolution can obtain results faster with the same hardware, especially at the earlier stages of the search. This is relevant when fewer compute resources are available. Evolution is, thus, a simple method to effectively discover high-quality architectures.

Sign in / Sign up

Export Citation Format

Share Document