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Recycling fly ash (FA) and furnace bottom ash (FBA) help with reducing greenhouse gas emissions, conserving natural resources, and minimizing waste accumulation. However, research on recycling FBA is progressing more slowly compared to FA. This research aims to investigate the combined use of FBA as a replacement for both fine aggregate and cement and its influence on the performance of mortar. The findings indicated that incorporating 25% FBA as a fine aggregate replacement and 10% or 20% ground FBA (GFBA) as a cement replacement significantly enhanced compressive strength after 28 and 56 days. Flexural strength was comparable to control mortar at 28 days and superior at 56 days. However, increasing the FBA content beyond 25% as a fine aggregate replacement reduced workability and increased porosity, which negatively affected mechanical performance and water absorption. Microstructural analyses revealed denser and more compact structures in the mortar with combined FBA replacement for both fine aggregate and cement, specifically 25% as a fine aggregate replacement and 10% and 20% as cement replacements. Optimal performance was noted in mixtures with Ca/Si and Ca/Al ratios within the ranges of 1.8–1.5 and 0.24–0.19, respectively. Trace element leaching analysis has not shown significant differences between GFBA, FA, and OPC. Regarding environmental impact assessment, using FBA as a fine aggregate replacement did not show a significant reduction in CO2 emissions, but replacing cement with FBA reduced emissions remarkably. Generally, using FBA as a replacement for both fine aggregate and cement in mortar enhances compressive and flexural strengths at optimal levels, promotes sustainability by reducing landfill waste and CO2 emissions, and supports cleaner production practices despite some workability challenges. [ABSTRACT FROM AUTHOR]

Controlled transport of biological cells in biomedical applications such as sorting, cell sequencing, and assembly of multicellular structures is a technological challenge. Research areas such as drug delivery or tissue engineering can benefit from precise cell location resulting in faster response rates or more complex tissue structures. Using computational methods, different soft magnetic elements with curved edges are designed to form a transport network, enabling transport and all functionalities for the manipulation of microbeads and cells on surfaces by rotational magnetic fields. Building blocks with bimodal functionalities due to segments of differently curved edges permit breakpoints as well as switchable transport via splitting and combining elements. Connecting the elements, networked paths are realized which allow variable movement patterns of magnetic carriers and cells. The direction of magnetic field rotation is altered to direct the beads and cells into different transport lines, and the exact timing is not critical. The networks are used to achieve deterministic movement of microbeads and cells with minimal intervention. Programmed transport over one millimeter with cell transport velocities of several micrometers per s is demonstrated. Based on scalable microchip technology, the networks can be integrated with CMOS‐compatible materials and straightforwardly combined with sensing and diagnostic structures. [ABSTRACT FROM AUTHOR]

The bond strength of steel reinforcement bars in concrete is of prime importance for the strength and serviceability of reinforced concrete structures. The composition of concrete directly affects the bond strength of steel bars in concrete. Research is ongoing to improve the bond properties of concrete with the addition of nanoparticles. In this paper, the effect of adding graphene nanoplatelets (GNP) to geopolymer concrete on the bond strength of steel bars in geopolymer concrete was investigated and compared with the bond strength of steel bars in ordinary portland cement (OPC) concrete. Slag and fly ash were used as aluminosilicate precursors, and ambient curing conditions were adopted for preparing geopolymer concrete. Specimens were cast with geopolymer concrete without and with GNP and OPC concrete without and with GNP. Steel bars of four different diameters (10, 12, 16, and 20 mm) were used for preparing the specimens. The quantity of GNP added in the concrete was 0.5% by weight of aluminosilicate materials in geopolymer concrete and 0.5% by weight of cement in OPC concrete. The addition of GNP to geopolymer concrete enhanced the bond strength by 13%–19% for the steel bars of diameters 10–20 mm. The bond strengths of steel bars in geopolymer concrete were found to be lower than the bond strength of steel bars in OPC concrete. Furthermore, the bond strengths were calculated using equations available in the design codes and available research studies on geopolymer and OPC concrete and compared with the experimental bond strengths. [ABSTRACT FROM AUTHOR]

There is a lack of effective disposal methods for the increasing amount of textile waste that is being generated worldwide. This is creating environmental concerns and burdening waste management facilities. In this study, we propose that cotton fibres that have been recycled from textile waste could be used as fibre reinforcement in cement mortar. Seven mix designs were prepared, which were based on the quantity (0.4%, 0.8%, 1.6% and 2.0% by the weight of the cement) and length (20 mm, 30 mm and 40 mm) of the cotton fibres. The physical properties, including workability, compressive strength, flexural strength, density and water absorption, were investigated. The workability of the cement mortar was reduced with the addition of the cotton fibres. The flexural strength of the cement mortar with the added cotton fibres was improved by up to 9%, compared to the flexural strength of the control samples. The compressive strengths of the samples generally decreased with the increase in the fibre content and length. However, the C0.8 mix showed a comparable compressive strength to the control mix at all curing ages, with a slight decrease of 2.5% on day 56 of curing. The results were further clarified using SEM images. The improvement in the flexural properties showed that the cotton fibres could be implemented as fibre reinforcement in cementitious composites. [ABSTRACT FROM AUTHOR]

The durability performance of geopolymer concrete against severe environmental conditions is important for implementing geopolymer binders as alternatives to ordinary portland cement (OPC). In this experimental investigation, the impact of adding graphene on the durability characteristics of geopolymer concrete was examined. Graphene was added at 0.5% by weight of aluminosilicate precursors in geopolymer concrete. Permeability, salt ponding, capillary sorptivity, and immersion in chemical agents were performed to assess the durability characteristics of geopolymer concrete without and with graphene, which were also compared with the durability characteristics of OPC concrete without and with graphene. It was found that the addition of graphene in geopolymer concrete reduced the permeable voids by 12% and water absorption by 9%, and improved the resistance against chloride penetration and sulfuric acid exposure. The compressive strength of geopolymer concrete increased by 20% with the addition of graphene. Also, an approximately 70% reduction in the initial and final rate of water absorption was observed in geopolymer concrete with the addition of graphene. [ABSTRACT FROM AUTHOR]

Various test methods and techniques are used to determine the shear strength of concrete. However, the available test methods and techniques used for determining the shear strength of concrete are prone to several inconsistencies and limitations, which cause inaccuracies in measuring the shear strength of concrete. A simple test method is proposed in this paper to achieve an accurate measurement of the shear strength of concrete. The proposed method was applied to two groups of concrete representing normal-strength concrete and high-strength concrete. The specimens failed at locations where the area was reduced, providing an accurate estimate of the shear strength of concrete. [ABSTRACT FROM AUTHOR]

The simultaneous separational control of motion of individual objects is vital to achieve high efficiency separation for biological analytes in biomedical applications. Here, we show the selective and directed movement of different populations of microbeads depending on their size in a flowless environment by means of a hexagonally structured soft-magnetic microchip platform. By adjusting strength and asymmetry of a modulated in-plane magnetic field, discrete and switchable movement patterns of two different types of beads above a magnetic surface structure are achieved. Starting from a heterogeneous mixture of bead populations and depending on the type of field sequences, directional forward transport of one type of beads is achieved, while the other bead population is immobilized. Despite significant size and magnetic content distributions within each population of microbeads, high separation efficiencies are demonstrated. The selection and movement processes are supported by full-scale magnetofluidic numerical simulations. The magnetic platform allowing multidirectional and selective microbead movement can greatly contribute to the progress of functional lab-on-chip and future diagnostics devices. [ABSTRACT FROM AUTHOR]

Precise movement control is a key feature for the use of superparamagnetic microbeads in medical and biological lab-on-chip applications. We demonstrate the unidirectional transport of magnetic and biological carriers along a chain of oval shaped magnetic thin film elements by in-plane rotating magnetic fields, enabling controllable manipulation and separation schemes. The same fundamental unidirectional movement is realized independent of the sense of magnetic field rotation and orientation of the magnetic pathway. The flowless directional transport of magnetically labeled rat embryonic fibroblasts is presented, validating the applicability of the structures for biological purposes. The lined up ferromagnetic structures are a critical building block for the construction of flexible pathways for biological lab-on-a-chip applications. [ABSTRACT FROM AUTHOR]

This paper investigates the effect of graphene on the properties of slag and fly ash-based ambient cured geopolymer paste and mortar. Graphene was added with five percentage (0.0%, 0.1%, 0.5%, 1.0% and 1.5%) of aluminosilicate materials by weight. The initial and final setting times of geopolymer pastes were reduced. The workability of geopolymer paste and mortar was slightly decreased with graphene. The 7-day and 28-day compressive strength of geopolymer mortar with 1.0% addition of graphene increased by 25% and 10%, respectively. The addition of 1% graphene could be considered as optimum proportion to improve the compressive strength of geopolymer mortar. [ABSTRACT FROM AUTHOR]

The guidance of labelled microcarriers in microfluidic environments is vital for lab‐on‐chip technology. In article number 1801201, Umer Sajjad, Enno Lage and Jeffrey McCord realize the independent positioning and sorting of mixed populations of superparamagnetic beads across magnetic patterns for biodiagnostic applications. Using hexagonally arranged ferromagnetic elements, a flexible two‐way separational motion of beads along spatial microcorridors is achieved. [ABSTRACT FROM AUTHOR]

The guidance of labeled microcarriers in microfluidic environments is a prerequisite to the development of magnetic pattern assisted lab‐on‐chip technology. Square wave modulations of in‐plane applied magnetic fields enable the forward and backward locomotion of superparamagnetic microspheres on discrete hexagonally arranged ferromagnetic structures in a flowless microfluidic environment at a single bead level. By using distinct magnetic field sequences, selective directional transportation and two‐way separational motion of different ensembles of beads across a varying stray magnetic field pattern is achieved. Microbeads can be moved along different directions along spatial microcorridors. The demonstrated realization of multifunctional patterned magnetic surfaces enables the controlled positioning and sorting of mixed populations of functionalized microcarriers for biodiagnostic applications. Multifunctional patterned magnetic surfaces enable flexible directional and two‐way lateral motion of superparamagnetic beads along spatial microcorridors in a 2D microfluidic environment. Square wave modulations of in‐plane applied magnetic fields form a variable stray magnetic field pattern for the size selective positioning and sorting of mixed populations of functionalized microcarriers for biodiagnostic applications. [ABSTRACT FROM AUTHOR]