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The purpose of this study is to design a plasmonic structure that can be used simultaneously as a heater and a refractive index sensor applicable for heating and sensing cycles of lab-on-chip (LOC).

The authors report on the full optical method applicable in the heating and sensing cycles of LOC based on the plasmonic nanostructure. The novelty of this proposed structure is due to the fact that a structure simultaneously acts as a heater and a sensor.

In terms of the performance of the proposed structure as an analyte detection sensor, in addition to the real-time measurement, there is no need to labeling the sample. In terms of the performance of the proposed structure as a plasmonic heater, the uniformity and speed of the heating and cooling cycles have been greatly improved. Also, there is no need for experts and laboratory conditions; therefore, our proposed method can meet the conditions of point of care testing.

The authors confirm that this work is original and has not been published elsewhere nor it is currently under consideration for publication elsewhere.

This study explores the feasibility of substituting freshwater with alternative water sources such as potable water (PW), harvested rainwater (HRW), stormwater (SW), borewell water (BW) and seawater (Sea W) in concrete manufacturing. The aim is to evaluate the potential of these alternative sources to support sustainable development, reduce environmental impact and conserve freshwater resources in the construction industry.

The research followed established concrete production standards and evaluated the chemical properties of various water sources. Fresh concrete characteristics, including setting time, workability and mechanical properties (compressive, split tensile and flexural strength), were tested at 7, 28 and 90 days. Durability assessments utilized the Volhard assay for chloride content, RCPT for chloride permeability and a physical sulfate attack test. Additionally, a life cycle assessment (LCA) examined the environmental impacts, while an economic analysis assessed cost implications for each water source.

The results showed only minor differences of 2%–3% in the fresh and mechanical properties of concrete using alternative water sources, with no significant changes in compressive, tensile or flexural strength compared to potable water. The Rapid Chloride Penetration Test (RCPT) and Nord Test techniques showed that all water sources, except seawater, are suitable for concrete mixing, as they enhance concrete durability due to their very low chloride ion concentrations, which minimize the risk of steel corrosion. The sulfate attack, including mass loss and expansion measurements for various water sources, indicates low susceptibility to except seawater. SEM and EDS HRW and SW also showed denser microstructures compared to Potable Water, indicating the absence of voids or cracks and the formation of ettringite needles, while seawater posed challenges due to high chloride content and corrosion risks. The LCA indicated that SW had the lowest environmental impact, while seawater posed substantial challenges. The economic analysis confirmed SW as the most cost-effective option, with all sources meeting production standards except seawater.

This study provides new insights into the sustainable use of non-potable water sources in concrete manufacturing. It demonstrates the viability of using HRW, SW and BW as alternative water sources to potable water, supporting sustainability goals in construction while conserving vital freshwater resources and reducing environmental impact.