Shear-thickening behavior of high-performance cement grouts — Influencing mix-design parameters

2011 ◽  
Vol 41 (3) ◽  
pp. 230-235 ◽  
Author(s):  
Ammar Yahia
2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Mohd. Ahmed ◽  
M. N. Qureshi ◽  
Javed Mallick ◽  
Mohd. Abul Hasan ◽  
Mahmoud Hussain

Concrete mix design is the science to obtain concrete proportions of cement, water, and aggregate, based on the particular concrete design method and their mix design parameters. However, the suitability of concrete proportion for high-performance concrete depends on resulting mix factors, namely, water, cement, fine aggregate, and coarse aggregate ratios. This paper implements the multicriteria decision-making techniques (MCDM) for ranking concrete mix factors and representative mix design methods. The study presents a framework to identify critical mix factors found from the concrete mix design methods for high-performance concrete using the two-phase AHP and TOPSIS approach. Three methods of concrete mix design, namely, American Concrete Institute (ACI) mix design method, Department of Energy (DOE) method, and Fineness Modulus (FM) method, are considered for ranking mix design methods and the resulting mix factors. Three hierarchy levels, having three criteria and seven subcriteria, and three alternatives are considered. The present research is attempted to provide MCDM framework to rank the concrete mix guidelines for any given environment such as concrete under sulphate and chloride attack and for evolving the performance-based concrete mix design techniques. Sensitivity and validation analysis is also provided to demonstrate the effectiveness of the proposed approach.


Author(s):  
Dhanvanth J.S. Talluri ◽  
HuanTan Nguyen ◽  
Reza Avazmohammadi ◽  
Amir K. Miri

Abstract Extrusion three-dimensional (3D) bioprinting typically requires an ad-hoc trial-and-error optimization of the bioink composition towards enhanced resolution. The bioink solutions are solidified after leaving cone-shaped or cylindrical nozzles. The presence of bioink instability not only hampers the extrusion resolution but also affects the behavior of embedded cellular components. This is a key factor in selecting bioinks and bioprinting design parameters for well-established desktop and handheld bioprinters. In this work, we developed an analytical solution for the process of bioink deposition and compared its predictions against numerical simulations of the deposition. We estimated the onset of bioink instability as a function of bioink rheological properties and nozzle geometry. Both analytical and simulation results demonstrated that enhancing shear-thinning behavior of the bioink stabilizes the printing process whereas bioink shear-thickening behavior induces an opposite effect through extending the toe region of the deposition. The present study serves as a benchmark for detailed simulations of the extrusion process for optimal bioprinting.


2021 ◽  
Vol 13 (5) ◽  
pp. 2756
Author(s):  
Federica Vitale ◽  
Maurizio Nicolella

Because the production of aggregates for mortar and concrete is no longer sustainable, many attempts have been made to replace natural aggregates (NA) with recycled aggregates (RA) sourced from factories, recycling centers, and human activities such as construction and demolition works (C&D). This article reviews papers concerning mortars with fine RA from C&D debris, and from the by-products of the manufacturing and recycling processes of building materials. A four-step methodology based on searching, screening, clustering, and summarizing was proposed. The clustering variables were the type of aggregate, mix design parameters, tested properties, patents, and availability on the market. The number and the type of the clustering variables of each paper were analysed and compared. The results showed that the mortars were mainly characterized through their physical and mechanical properties, whereas few durability and thermal analyses were carried out. Moreover, few fine RA were sourced from the production waste of construction materials. Finally, there were no patents or products available on the market. The outcomes presented in this paper underlined the research trends that are useful to improve the knowledge on the suitability of fine RA from building-related processes in mortars.


Author(s):  
Umar Ibrahim Minhas ◽  
Roger Woods ◽  
Georgios Karakonstantis

AbstractWhilst FPGAs have been used in cloud ecosystems, it is still extremely challenging to achieve high compute density when mapping heterogeneous multi-tasks on shared resources at runtime. This work addresses this by treating the FPGA resource as a service and employing multi-task processing at the high level, design space exploration and static off-line partitioning in order to allow more efficient mapping of heterogeneous tasks onto the FPGA. In addition, a new, comprehensive runtime functional simulator is used to evaluate the effect of various spatial and temporal constraints on both the existing and new approaches when varying system design parameters. A comprehensive suite of real high performance computing tasks was implemented on a Nallatech 385 FPGA card and show that our approach can provide on average 2.9 × and 2.3 × higher system throughput for compute and mixed intensity tasks, while 0.2 × lower for memory intensive tasks due to external memory access latency and bandwidth limitations. The work has been extended by introducing a novel scheduling scheme to enhance temporal utilization of resources when using the proposed approach. Additional results for large queues of mixed intensity tasks (compute and memory) show that the proposed partitioning and scheduling approach can provide higher than 3 × system speedup over previous schemes.


Soft Matter ◽  
2021 ◽  
Author(s):  
Vikram Rathee ◽  
Alessandro Monti ◽  
Marco Edoardo Rosti ◽  
Amy Q Shen

Shear thickening in stable dense colloidal suspensions is a reversible phenomenon and no hysteresis is observed in the flow curve measurements. However, a reduction in the stability of colloids promotes...


RSC Advances ◽  
2017 ◽  
Vol 7 (14) ◽  
pp. 8118-8130 ◽  
Author(s):  
Hongbin Yang ◽  
Wanli Kang ◽  
Hairong Wu ◽  
Yang Yu ◽  
Zhou Zhu ◽  
...  

The dispersed low-elastic microsphere system shows shear-thickening behavior because of the microstructure change and the interaction of internal forces.


2000 ◽  
Author(s):  
S. R. Habibi

Abstract This paper considers the design of a high performance hydrostatic actuation system referred to as the ElectroHydraulic Actuator (EHA). The expected performance of EHA and its dominant design parameters are identified by using mathematical modeling. The design parameters are classified into Direct and Indirect categories based on the measure of their accessibility to the designer. The Direct parameters are directly quantifiable and, can be linked to the performance of EHA through a set of mathematical functions. A prototype of EHA has been produced and described. The mathematical functions linking performance to design parameters are used to investigate design trade-offs. Design improvements to the prototype are suggested by using constrained quadratic programming.


2015 ◽  
Vol 72 ◽  
pp. 51-62 ◽  
Author(s):  
Ha Thanh Le ◽  
Matthias Müller ◽  
Karsten Siewert ◽  
Horst-Michael Ludwig

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