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Single-atom catalysts (SACs), which are low-cost, contain earth-abundant metals, and feature two-dimensional material supports, have shown great potential for us in a wide range of electrochemical reactions, including the CO2 reduction reaction (CO2RR) to convert CO2 to valuable chemicals and fuels. In recent years, substantial advances have been achieved in the preparation methodologies, with improved catalytic performances, but the underlying structure–activity relationship from a general perspective remains elusive. In particular, it is urgent to summarize the progress made on SACs with diatom metal centers toward efficient CO2RR. Based on the recent progress in this area, this review synopsizes the fundamental understandings of non-noble metal-based SACs for CO2RR using selected examples. We also highlight the representative atomic structures of active sites from the latest progress, including M–N–C, heteroatom co-doping, vacancy/edge defects and bimetallic SACs, with the aim of elucidating the nature of active sites on various 2D substrates. Moreover, we summarize the spectroscopic and computational studies to verify the atomic-level regulation of the geometric and electronic properties of SACs. We anticipate that this review will deepen the mechanistic understanding of the structure–performance relationship and inspire future studies on SACs for CO2RR. [ABSTRACT FROM AUTHOR]

The precipitation of authigenic quartz plays a significant role to reduce the reservoir characteristics and enhance the stiffness of the rock. The Es1 sandstone of Shahejie Formation is acting as a significant hydrocarbon producing rock in the Nanpu Sag. Various methods like thin section petrography, cathodoluminescence (CL), scanning electron microscope (SEM, with EDS), and electron microprobe analysis has been used to reveal the origin of quartz cement as well as to evaluate the effect of quartz cement on reservoir quality. The studied sandstone is classified as immature to mature feldspathic litharenite and lithic arkose and consists of quartz, feldspar, rock fragments and micas. Petrographic studies and SEM analysis shows that the authigenic quartz is acting a significant cement that reduces the reservoir quality. Whereas clay minerals (kaolinite and mixed layer illite to smectite) are dominant in the Es1 sandstone, that can reduce the reservoir quality. SEM, CL and thin section analysis reveal that there are two stages of quartz cement in the studied samples; that are pore filling authigenic cement and quartz overgrowth cement. Fluid inclusion homogenization temperatures shows that stages of quartz cement were developed with continuous process from 70°C to 130°C. Quartz cements were generally originated from I/S reaction, feldspar dissolution, conversion of rock fragments and pressure solution. Feldspar dissolution (K‐feldspar) and kaolinite to illite reaction is an insignificant silica source for the silica cement which is internally precipitated in a close system with diffusion transporting mechanism. Overall, quartz cement significantly enhance the rock strengthen and brittleness effectively as well as it reduce the overall reservoir quality. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSC) comprising of organic–inorganic lead halide composition have been considered as the future candidates for substituting the costly crystalline silicon-based solar cells if the challenges of efficiency and stability are adequately addressed. PSCs have been known for the employment of costly materials serving as electron transport, hole transport layers and back contact electrode such as gold, silver, or aluminum, needing thermal deposition in high vacuum ambiance. Metallic electrodes have been observed as not robust and thus, prone to quick degradation hindering the overall photovoltaic functionality of PSC devices. Carbon-modified PSCs via utilization of carbon nanotubes (CNTs) have been a favorable choice in terms of longer stability and efficiency. Considering the overpowering potential of CNTs in transforming PSC device functionality, current review has been designed to elucidate the most recent progressions carried out in utilization of CNTs in PSCs. Furthermore, this review focussed a critical view on the utilization of CNTs-based PSCs for lower fill factors and other photovoltaic parameters in addition to the account of ways to solve these concerns. Photovoltaic community researchers need to develop cost effective methods for resolving the lower efficiencies and fill factors associated with use of CNTs and can further explore different novel materials to successfully modify CNTs for employment in PSCs. [ABSTRACT FROM AUTHOR]

Environmental pollution produced due to direct and untreated release of toxic organic pollutants such as dyes from the textile industries is not only effect the human life but also contaminates the ecosystem through different transferal modes. Green nanomaterials synthesized by using biological reducing agents offer sustainable, economically viable, facile, rapid and eco-friendly approach with photocatalytic degradation efficiencies >90% for organic dyes over the other traditional technologies. Current review has for the first time comprehensively abridged the suitability of green nanoparticles over chemogenic nanoparticles, the remediative role of these biogenic nanoparticles with major emphasis on the recent progressions in the photocatalysis of different toxic dyes and pollutants. Unlike physicochemically processed nanoparticles, biogenic nanoparticles has profound contribution to the sustainable development goals due to their cleaner and economical synthesis in addition to their detoxifying role. Meticulous review of the publications are strongly suggestive of the adoptability of biogenic nanoparticles at an implementation scale for their auspicious remediative role in addition to facile fabrication, natural reducing agents based synthetic mode, toxicity free and sustainable nature. However, the studies are also indicative of the need for utilization of biogenic synthesis at practical scale to derive maximum sustainability and ecological benefits. [ABSTRACT FROM AUTHOR]

The satellite remote sensing method is an important low-cost technique for the identification, mapping, and collecting information on potential areas of surface lithologies in areas of appropriate exposure. Multiple techniques have been developed which are utilized for the geological mapping from satellite data. This study is based on the band ratios and spectral analogue method for identifying and characterizing stratigraphy based on using satellite data. The study area (approx. 20 sq. km) is located in Chitral District which lies in the northwest of Pakistan. This area is based on the Devonian and Quaternary sedimentary and metamorphosed rock. ASTER data was used for the geological characterization in a way that image processed first, and then interpretation was done on the processed image. In this study, ASTER satellite data was atmospherically and radiometrically corrected before the lithological characterization. The spectral analogue method and band combination (532) in RGB image were powerful in distinguishing various rock units. Field survey was carried out to measure the accuracy of the remote sensing–based lithological maps. Accuracy of the produced map was evaluated through calculating the kappa index. Overall accuracy and a thematic accuracy of 84% were achieved for geological formations. [ABSTRACT FROM AUTHOR]

[Display omitted] Ammonia (NH 3) is a significant energy source, in addition to its conventional uses for inorganic fertilizers, explosives, dyes, and resins. Recently, there has been tremendous interest towards electrochemical NH 3 synthesis via nitrogen reduction reaction (NRR) under ambient conditions, to substitute the conventional Haber-Bosch process. In this review, the fundamentals and mechanism for electrochemical nitrogen fixation are summarized. The NRR performances for all the important electrocatalysts with a special focus on two-dimensional (2D) materials, and theoretical insights from recent literature are comprehensively summarized. Among them, 2D materials are especially promising due to the versatile tools that can be leveraged for the structure design. Based on these studies, guidelines for achieving high selectivity and high NRR catalytic activity are provided. Strategies for the catalyst design, cell configuration, and electrolyte choices to tackle several challenges related to NRR are delineated in a holistic way. Furthermore, important aspect of environmental contamination effect is also discussed. This review provides direction for electrochemical catalyst engineering and guidance for experimental practices to explore the realm of electrochemical nitrogen reduction reaction. [ABSTRACT FROM AUTHOR]

Purpose: In surface mount assembly (SMA) process, small components are subjected to high temperature variations, which result in components' deformation and cracking. Because of this phenomenon, cracks are formed in the body of carbonyl powder ceramic inductor (CPCI) in the preheat and cooling stages of the reflow oven. These cracks become the main cause of board failure in the ageing process. The purpose of this paper is to ascertain the thermal stress, thermal expansion of carbonyl iron ceramics and its effects on crack commencement and proliferation in the preheat stage of reflow oven. Moreover, this paper also categorized and suggested important parameters of reflow profile that could be used to eliminate these thermal shock failures. Design/methodology/approach: In this paper, two different reflow profiles were studied that evaluate the thermal shock of CPCI during varying ΔT at the preheat zone of the reflow oven. In the first profile, the change in temperature ΔT at preheat zone was set to 3.26°C/s, which has resulted in a number of device failures because of migration of micro cracks through the CPCI. In the second profile, this ΔT at preheat stage is minimized to 2.06°C/s that eliminated the thermal stresses; hence, the failure rates were significantly reduced. Findings: TMPC0618H series lead (Pb)-free CPCI is selected for this study and its thermal expansion and thermal shock are observed in the reflow process. It is inferred from the results that high ΔT at preheat zone generates cracks in the carbonyl powder-type ceramics that cause device failure in the board ageing process. Comparing materials, carbonyl powder ceramic components are less resistant to thermal shock and a lower rate of temperature change is desirable. Originality/value: The proposed study presents an experimental analysis for mitigating the thermal shock defects. The realization of the proposed approach is validated with experimental data from the printed circuit boards manufacturing process. [ABSTRACT FROM AUTHOR]

The usage of natural dyes for coloration has attained attention in recent years due to their ecofriendly environment. Therefore, in this study, orange peel solvent extract is used as a natural dye for coloring Tencel fabric samples. Pre-mordanting and post-mordanting methods were accomplished with two different mordants, i.e. ferrous sulfate and copper sulfate. The dyeing shade effects were retrieved through colorfastness properties according to the ISO standardizations. The results revealed that the best color shade (K / S : 4.56) was achieved using mordant ferrous sulfate through the post-mordanting method. The effect of lightfastness on all dyed Tencel fabric samples was observed good (3–4) in both mordanting methods. However, mordant ferrous sulfate showed better lightfastness (4) than copper sulfate (3–3.5) through both mordanting methods. Comparatively, in the rubbing fastness, copper sulfate has superior results in both mordanting methods. The ferrous and copper sulfates in both mordanting methods have similar tests results (4.5) of washing fastness, acidic and alkaline perspiration. Furthermore, the FTIR test substantiated that not any structural change occurred through orange peel dyed Tencel fabric samples through both methods. TGA observed samples were relatively stable up to 300∘C temperature. Overall, the best results of colorfastness for Tencel fabric samples were obtained with ferrous sulfate mordant through the post-mordanting extraction method. [ABSTRACT FROM AUTHOR]