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An efficient, highly sensitive, and selective electrochemical sensor using PtNPs sandwiched graphene layered modified graphite pencil electrode.

The building sector, due to the significant energy and environmental footprints it creates, needs to adopt sustainable approaches to help prevent global warming and climate change. Sustainable Building (SB) rating systems have been developed around the world as a method to promote sustainability in this sector. Water is one of the most vital natural resources, and is extensively consumed in the building sector. This article examines the coverage of water-related aspects in 11 prominent SB rating systems under the three key sustainability dimensions: environmental, economic, and social, using a comprehensive coverage analysis approach. Findings highlight a wide range of variation between the examined SB rating systems in terms of water attributes being assessed, water assessment criteria used, the optimal number of these criteria, and the weight assigned to them. Results also show that in general, most of the examined systems exhibit low representativeness and comprehensive coverage of major water subcategories and themes related to sustainable buildings. However, some moderate to high comprehensive coverage was found in water attributes that focus on the environmental and social aspects. The results indicate that representative and comprehensive coverage of social-related water attributes are less than that of environment-related water attributes. The results also highlighted the effectiveness of using coverage analysis techniques as a systematic and efficient way to assess comprehensive coverage of water criteria in SB rating systems.

In the petroleum industry, ordinary Portland cement (OPC) is utilized for different cementing applications. Yet, there are some technical and environmental issues for the usage of OPC in well cementing. The technical problems include gas invasion while setting, instability at corrosive environments, cement failure while perforation and fracturing due to high stiffness and brittleness, and strength reduction and thermal instability at elevated temperatures. Moreover, OPC production consumes massive energy and generates high greenhouse gas emissions. This study introduced the first hematite-based class F fly ash geopolymer formulation that can be used in oil and gas well cementing. Different properties of the designed slurry and hardened samples such as rheology, thickening time, strength, and elastic and petrophysical properties were evaluated. Moreover, mixability and pumpability challenges of heavy-weight geopolymer slurries were investigated. Unlike most of the studies in the literature, this work used 4 M NaOH solution only as an activator that can reduce the overall cost. The results showed that increasing the hematite percentage significantly decreased the thickening time. The developed formulation fell within the recommended fluid loss ranges for some cementing applications without using a fluid loss control additive. A proposed mixture of retarder and superplasticizer was introduced to enhance the thickening time by almost 5 times. The compressive strength increased by 49% and the tensile strength was enhanced by 27.4% by increasing the curing time from 1 to 7 days. The improvement in both compressive and tensile strength with curing time indicated that the geopolymerization reaction continued for extended time but with a smaller rate. The developed slurry acted more like a power law fluid at low temperatures and more like a Bingham plastic fluid at high temperatures. The elastic properties of the developed geopolymer samples proved that they are more flexible than some cement systems.