No abstract

The signature of Late palaeozoic glaciation, a pan‐Gondwanaland palaeoclimatic event, is recorded in the Talchir Formation (Late Carboniferous to Early Permian), the basal‐most litho‐unit within the Gondwana Supergroup (Late Carboniferous–Early Cretaceous) in peninsular India. About 200 m thick sedimentary succession of the Talchir Formation, exposed in the Hasdeo River section in the Son Valley Basin, Central India, manifests signatures of deposition by melting of glaciers near to the ice‐grounding line. Evidence of glacial influences is prevalent in the lower‐middle part of the succession and represented by glacial tillites with faceted/striated gravels and bullet‐shaped clasts, dropstones and ice‐rafted debris (IRD), associated with various sediment gravity flow deposits. In the middle‐upper part of the succession, records of post‐glacial marine incursions are preserved as thick sandstone and sandstone‐mudstone heteroliths of a shallow marine shore‐shelf depositional regime. These are characterized by abundant tidal and wave signatures, with marine bivalve fossils and trace fossils of marine invertebrates. The upward decrease in size and abundance of the IRDs indicates a gradual decrease in glacial influences, with landward incursion of the marine depositional systems over the proglacial systems. Multiple stacked progradational and retrogradational stratal stacking patterns formed by alternating glacigenic and marginal marine dominated processes signify multiple transgressive‐regressive (T‐R) cycles, manifesting repeated advancements and retreats of the glacier, associated with sea level rise and marine incursions into the land. The top part of the succession, characterized by fine‐grained siltstone/mudstone without any IRD, suggests sedimentation at a relatively deeper part of the basin, indicating the strong influence of the eustatic rise caused by significant melting of the retreating ice sheet. Stacked T‐R cycles bounded by distinct facies architecture define multiple system tracts confined within three major deglaciation sequences within the studied Talchir Formation, suggesting multiple phases of advance‐retreats of the ice sheet and significant marine onlaps within the continental Gondwanaland under the Late Palaeozoic icehouse‐greenhouse climatic change.

Resource depletion is a concern for the global economy; many think that available resources on the planet will not be able to cater to an ever-growing population. Thus, economies are trying to become circular, leaving behind the linear tradition linear approach. In the circular economy (CE), physical resources and energy are made to loop back into the supply chain (SC) for a more extended period. Proper selection of suppliers is an essential criterion towards proper execution of the CE principle in SC. In this research, we have constructed a framework for evaluating the supplier concerning the CE implementation. Further, this research identifies the criterion and sub-criterion, which are pertinent for evaluating the supplier in CE context. Fuzzybased 'Criteria Importance Through Inter-Criteria Correlation (CRITIC)' method is justifiably applied to determine the aggregated weights of the criteria. Finally, 'Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS)' method is used to determine the suppliers' ranking in the Indian automobile industry. Six criteria and 24 sub-criteria are obtained as per recent literature and then inputs from experts. 'Environment' criterion came out as the most favourable criterion with a subjective weight of 0.230. The current research is one of the first such attempts to provide criteria for supplier selection in a CE environment. The developed framework would help organisations in implementing CE-based supplier selection. The identified criteria and sub-criteria would provide organisations with means to evaluate suppliers and help suppliers develop an effective and efficient CE based on the SC.

Rice husk ash (RHA) is an agricultural based pozzolanic material, generated by rice mills in huge quantities. This paper summarizes the experimental work of concrete in which ordinary Portland cement (OPC) cement were replaced by Rice husk ash (RHA). Partial replacement of OPC cement was carried out at 0% to 20% in steps of 5% and compared with 0% replacement. In this work different tests were performed as slump test, compaction factor, compression test and split tensile test to find the suitable percentage replacement of cement by RHA. Compression and split tests were performed for 7days and 28 days of curing and result shows some variation in both tests in every proportion. After performing tests, the results suggest that up to 15% replacement of RHA for cement is suitable for making concrete.

Concrete slab is the most important component of any building structure. Slab provides great thermal comfort and great lifestyle for human beings. Concrete slab consumes more concrete in the casting for providing flooring and roofing. Concrete is heavy in weight and more than 5% of CO2 is created during the manufacturing of cement that goes into it. In this paper we studied that reduction of concrete in slab may be suitable and useful for making lightweight and most effective concrete slab after using High density polyethylene hollow spheres. The use of hollow spheres virtually eliminating all concrete from the middle of the slab which is not performing any structural function, thereby reducing the self-weight and increasing the efficiency of the slab. This method introducing the 30 to 50% lighter slab than can reduce the loads on the columns, walls and foundations. It also useful in reducing the cost and emission of CO2.