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Träfflista för sökning "WFRF:(Gadhamshetty Venkataramana) "

Search: WFRF:(Gadhamshetty Venkataramana)

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1.
  • Bathi, Jejal Reddy, et al. (author)
  • Behavior of engineered nanoparticles in aquatic environmental samples : Current status and challenges
  • 2021
  • In: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 793
  • Research review (peer-reviewed)abstract
    • The increasing use of engineered nanoparticles (ENPs) in consumer products has led to their increased presence in natural water systems. Here, we present a critical overview of the studies that analyzed the fate and transport behavior of ENPs using real environmental samples. We focused on cerium dioxide, titanium dioxide, silver, carbon nanotubes, and zinc oxide, the widely used ENPs in consumer products. Under field scale settings, the transformation rates of ENPs and subsequently their physicochemical properties (e.g., toxicity and bioavailability) are primarily influenced by the modes of interactions among ENPs and natural organic matter. Other typical parameters include factors related to water chemistry, hydrodynamics, and surface and electronic properties of ENPs. Overall, future nanomanufacturing processes should fully consider the health, safety, and environmental impacts without compromising the functionality of consumer products.
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2.
  • Bheemasetti, Sravani, et al. (author)
  • Upcycling the solid wastes as precursors for graphene production
  • 2023
  • In: Graphene Extraction from Waste. - : Elsevier. - 9780323909143 - 9780323909150 ; , s. 1-21
  • Book chapter (peer-reviewed)abstract
    • Owing to limited markets for recycled products, the United States annually discards~294 million tons of municipal solid waste (MSW) into landfills. These recycling rates for plastics and food wastes are as low as 7% and 3%, respectively. There is a need for stimulating innovative strategies for upcycling MSWs. This chapter discusses viable strategies for upcycling MSWs as precursors for graphene production using well-established nano-manufacturing techniques. We discuss the use of readily available MSW components as raw materials and the waste-to-energy infrastructure as a source of waste heat.
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3.
  • Chilkoor, Govinda, et al. (author)
  • Hexagonal Boron Nitride : The Thinnest Insulating Barrier to Microbial Corrosion
  • 2018
  • In: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 12:3, s. 2242-2252
  • Journal article (peer-reviewed)abstract
    • We report the use of a single layer of two-dimensional hexagonal boron nitride (SL-hBN) as the thinnest insulating barrier to microbial corrosion induced by the sulfate-reducing bacteria Desulfovibrio alaskensis G20. We used electrochemical methods to assess the corrosion resistance of SL-hBN on copper against the effects of both the planktonic and sessile forms of the sulfate-reducing bacteria. Cyclic voltammetry results show that SL-hBN-Cu is effective in suppressing corrosion effects of the planktonic cells at potentials as high as 0.2 V (vs Ag/AgCl). The peak anodic current for the SL-hBN coatings is ∼36 times lower than that of bare Cu. Linear polarization resistance tests confirm that the SL-hBN coatings serve as a barrier against corrosive effects of the G20 biofilm when compared to bare Cu. The SL-hBN serves as an impermeable barrier to aggressive metabolites and offers ∼91% corrosion inhibition efficiency, which is comparable to much thicker commercial coatings such as polyaniline. In addition to impermeability, the insulating nature of SL-hBN suppresses galvanic effects and improves its ability to combat microbial corrosion.
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4.
  • Chilkoor, Govinda, et al. (author)
  • Sustainability of renewable fuel infrastructure : a screening LCA case study of anticorrosive graphene oxide epoxy liners in steel tanks for the storage of biodiesel and its blends
  • 2017
  • In: Environmental Science. - : Royal Society of Chemistry. - 2050-7887 .- 2050-7895. ; 19:2, s. 141-153
  • Journal article (peer-reviewed)abstract
    • Biodiesel is a widely used fuel that meets the renewable fuel standards developed under Energy Policy Act of 2005. However, biodiesel is known to pose a series of abiotic and biotic corrosion risks to storage tanks. A typical practice (incumbent system) used to protect the tanks from the risks include: (i) coat the interior surface of the tank with solvent free epoxy (SFE) liner, and (ii) add a biocide in the tank. We present a screening-level, life cycle assessment study to evaluate and compare the environmental performance of graphene-oxide (GO)-epoxy (GOE) liner with the incumbent system. TRACI is used as an impact assessment tool to model midpoint environmental impacts for the ten categories: global warming potential (GWP, kg CO2 eq.); acidification potential (AP, kg SO2 eq.); potential human health damage impacts due to carcinogens (HH-CP, CTUh) and non-carcinogens (HH-NCP, CTUh); potential respiratory effects (REP, kg PM2.5 eq); eutrophication potential (EP, kg N eq); ozone depletion potential (ODP kg CFC-11 eq); ecotoxicity potential (ETXP, CTUe); smog formation potential (SFP kg O3 eq); and fossil fuel depletion potential (FFDP MJ surplus). The equivalent functional unit of the LCA study is designed to protect the 30 m2 of the interior surface (unalloyed steel sheet) of a 10,000 liters biodiesel tank against abiotic and biotic corrosion during its service life of 20 years. Overall, this LCA study highlights an improved environmental performance for the GOE liner compared to the incumbent system; GOE-liner system showed: 91% lower ODP impacts; 59% smaller for REP; 62% smaller for AP; 67-69% smaller for GWP and HH-CP; 72-76% smaller for EP, SFP, and FFDP; and 81-83% smaller for ETXP and HH-NCP categories. The scenario analysis study reveals that these potential impacts change by less than 15% when the GOE liners are functionalized with silanized-GO nanosheets or GO-reinforced, polyvinyl carbazole to improve the antimicrobial properties. The results from uncertainty analysis indicate that the impacts for the incumbent system are more sensitive to changes in key modeling parameters compared to that for GOE liner system.
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5.
  • Islam, Jamil, et al. (author)
  • Graphene as thinnest coating on copper electrodes in microbial methanol fuel cells
  • 2023
  • In: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 17:1, s. 137-145
  • Journal article (peer-reviewed)abstract
    • Dehydrogenation of methanol (CH3OH) into direct current (DC) in fuel cells can be a potential energy conversion technology. However, their development is currently hampered by the high cost of electrocatalysts based on platinum and palladium, slow kinetics, the formation of carbon monoxide intermediates, and the requirement for high temperatures. Here, we report the use of graphene layers (GL) for generating DC electricity from microbially driven methanol dehydrogenation on underlying copper (Cu) surfaces. Genetically tractable Rhodobacter sphaeroides 2.4.1 (Rsp), a nonarchetypical methylotroph, was used for dehydrogenating methanol at the GL-Cu surfaces. We use electrochemical methods, microscopy, and spectroscopy methods to assess the effects of GL on methanol dehydrogenation by Rsp cells. The GL-Cu offers a 5-fold higher power density and 4-fold higher current density compared to bare Cu. The GL lowers charge transfer resistance to methanol dehydrogenation by 4 orders of magnitude by mitigating issues related to pitting corrosion of underlying Cu surfaces. The presented approach for catalyst-free methanol dehydrogenation on copper electrodes can improve the overall sustainability of fuel cell technologies.
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6.
  • Oruganti, Raj Kumar, et al. (author)
  • A comprehensive review on the use of algal-bacterial systems for wastewater treatment with emphasis on nutrient and micropollutant removal
  • 2022
  • In: Bioengineered. - : Taylor & Francis. - 2165-5979 .- 2165-5987. ; 13:4, s. 10412-10453
  • Journal article (peer-reviewed)abstract
    • The scarcity of water resources and environmental pollution have highlighted the need for sustainable wastewater treatment. Existing conventional treatment systems are energy-intensive and not always able to meet stringent disposal standards. Recently, algal-bacterial systems have emerged as environmentally friendly sustainable processes for wastewater treatment and resource recovery. The algal-bacterial systems work on the principle of the symbiotic relationship between algae and bacteria. This paper comprehensively discusses the most recent studies on algal-bacterial systems for wastewater treatment, factors affecting the treatment, and aspects of resource recovery from the biomass. The algal-bacterial interaction includes cell-to-cell communication, substrate exchange, and horizontal gene transfer. The quorum sensing (QS) molecules and their effects on algal?bacterial interactions are briefly discussed. The effect of the factors such as pH, temperature, C/N/P ratio, light intensity, and external aeration on the algal-bacterial systems have been discussed. An overview of the modeling aspects of algal-bacterial systems has been provided. The algal-bacterial systems have the potential for removing micropollutants because of the diverse possible interactions between algae-bacteria. The removal mechanisms of micropollutants ? sorption, biodegradation, and photodegradation, have been reviewed. The harvesting methods and resource recovery aspects have been presented. The major challenges associated with algal-bacterial systems for real scale implementation and future perspectives have been discussed. Integrating wastewater treatment with the algal biorefinery concept reduces the overall waste component in a wastewater treatment system by converting the biomass into a useful product, resulting in a sustainable system that contributes to the circular bioeconomy.
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7.
  • Oruganti, Raj Kumar, et al. (author)
  • Artificial intelligence and machine learning tools for high-performance microalgal wastewater treatment and algal biorefinery : a critical review
  • 2023
  • In: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 876
  • Research review (peer-reviewed)abstract
    • The increased water scarcity, depletion of freshwater resources, and rising environmental awareness are stressing for the development of sustainable wastewater treatment processes. Microalgae-based wastewater treatment has resulted in a paradigm shift in our approach toward nutrient removal and simultaneous resource recovery from wastewater. Wastewater treatment and the generation of biofuels and bioproducts from microalgae can be coupled to promote the circular economy synergistically. A microalgal biorefinery transforms microalgal biomass into biofuels, bioactive chemicals, and biomaterials. The large-scale cultivation of microalgae is essential for the commercialization and industrialization of microalgae biorefinery. However, the inherent complexity of microalgal cultivation parameters regarding physiological and illumination parameters renders it challenging to facilitate a smooth and cost-effective operation. Artificial intelligence (AI)/machine learning algorithms (MLA) offer innovative strategies for assessing, predicting, and regulating uncertainties in algal wastewater treatment and biorefinery. The current study presents a critical review of the most promising AI/MLAs that demonstrate a potential to be applied in microalgal technologies. The most commonly used MLAs include artificial neural networks, support vector machine, genetic algorithms, decision tree, and random forest algorithms. Recent developments in AI have made it possible to combine cutting-edge techniques from AI research fields with microalgae for accurate analysis of large datasets. MLAs have been extensively studied for their potential in microalgae detection and classification. However, the ML application in microalgal industries, such as optimizing microalgae cultivation for increased biomass productivity, is still in its infancy. Incorporating smart AI/ML-enabled Internet of Things (IoT) based technologies can help the microalgal industries to operate effectively with minimum resources. Future research directions are also highlighted, and some of the challenges and perspectives of AI/ML are outlined. As the world is entering the digitalized industrial era, this review provides an insightful discussion about intelligent microalgal wastewater treatment and biorefinery for researchers in the field of microalgae.
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8.
  • Shanmugam, Kavitha, et al. (author)
  • Advanced High-Strength Steel and Carbon Fiber Reinforced Polymer Composite Body in White for Passenger Cars : Environmental Performance and Sustainable Return on Investment under Different Propulsion Modes
  • 2019
  • In: ACS Sustainable Chemistry and Engineering. - : AMER CHEMICAL SOC. - 2168-0485. ; 7:5, s. 4951-4963
  • Journal article (peer-reviewed)abstract
    • Vehicle lightweighting strategies must deliver sustainable returns to customers and society. This work evaluates the sustainable return on investment (SROI) of lightweighted advanced high strength steel (AHSS) and carbon fiber reinforced polymer (CFRP)-intensive multimaterial bodies in white (BIWs) for automobiles. The SROI depends on the lightweighted BIW's manufacturing cost and the difference in sustainable cost between a baseline (mild steel) BIW and the lightweighted alternative. The sustainable cost is the sum of the customer's lifetime fuel (or electricity) costs and the costs of environmental externalities. A cradle-to-grave life cycle assessment (LCA) was conducted to quantify the environmental impacts of CFRP and AHSS BIWs in gasoline-fueled cars, bioethanol (E85)-fueled cars, and battery electric vehicles (BEVs) driven for a lifetime distance of 200 000 km. For cars fueled with gasoline- or corn-based bioethanol, the CFRP BIW yielded the lowest SROI; the AHSS BIW performed best for BEVs and cars fueled with wood bioethanol. However, the commercial availability of recycled carbon fiber should increase the SROI of the CFRP BIW in the future. Additionally, the SROI of CFRP BIWs is maximized when carbon fiber production is done using energy from a low carbon-intensity electric grid or decentralized sources such as waste-to-energy incineration plants.
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9.
  • Upadhyayula, Venkata K.K., et al. (author)
  • Advancing game changing academic research concepts to commercialization : A Life Cycle Assessment (LCA) based sustainability framework for making informed decisions in Technology Valley of Death (TVD)
  • 2018
  • In: Resources, Conservation and Recycling. - : Elsevier BV. - 0921-3449 .- 1879-0658. ; 133, s. 404-416
  • Journal article (peer-reviewed)abstract
    • Many Game Changing Innovations (GCIs) from the academic institutions struggle in the Technology Valley of Death (TVD) and they fail to reach commercialization. The academic researchers often lack motivation to seek entrepreneurial opportunities for their GCIs. They are often discouraged after considering the burden required to convince private investors to finance their GCIs beyond technology readiness level 4. Further, many academic institutions lack a structured framework to bridge the divide between a basic research and viable product. Here we propose a four-pronged approach for developing sustainability performance metrics that can be used by early investors to understand the commercialization prospects of the GCIs: (1) conduct a screening-level LCA of the GCI and simultaneously reduce uncertainties of underlying data and technological readiness; (2) compare the LCA performance of the GCI with similar commercial products in the target market; (3) factor the LCA results into investment evaluation methods; and (4) transform LCA results into indicators that reflect sustainability performance of the innovation. Finally, we present a case study that highlights the use of this approach for developing commercial opportunities for the emerging graphene-composites as corrosion resistant coatings for civil infrastructure applications. The paper also suggests an approach for promoting a sustainability driven innovation culture in academia.
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10.
  • Upadhyayula, Venkata K. K., et al. (author)
  • Screening-Level Life Cycle Assessment of Graphene-Poly(ether imide) Coatings Protecting Unalloyed Steel from Severe Atmospheric Corrosion
  • 2017
  • In: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 5:3, s. 2656-2667
  • Journal article (peer-reviewed)abstract
    • A major concern for exposed steel in structural applications is susceptibility to atmospheric corrosion. The International Organization for Standardization classifies atmospheric environments into six zones, C1-C5 and CX, based on factors such as humidity, airborne salinity, and acidic pollutants. The C5 and CX zones are characterized by aggressive atmospheric corrosivity that results in mass losses from steel structures. hot-dipped galvanized (HDG) zinc coatings are typically used to protect steel in C5 and CX environments. HDG coatings suffer from disadvantages related to shorter service lives and the need for frequent maintenance cycles. Graphene-reinforced poly(ether imide) (PEI) coatings have been proposed as suitable alternatives to address these issues. However, general concerns regarding the implications of nanomaterials make it necessary to understand the potential environmental impacts of these coatings. A screening-level cradle-to-grave life cycle assessment is conducted to evaluate the environmental performance of a graphene-PEI-steel structure when compared with a traditional HDG-zinc-steel structure. Impact assessment scores are calculated using the Tool for the Reduction and Assessment of Environmental and other Potential impacts v2.1 and SimaPro (v8.0.3). When considering inventory uncertainty, the graphene-PEI-steel structure yields smaller potential impacts in five of the ten categories assessed when assuming the graphene-based coating requires no maintenance during the service life of the structure. Scenario-based sensitivity studies reveal that the potential impacts are highly sensitive to the service life and maintenance needs of the coating, but insensitive to the use of thermally or chemically functionalized graphene to improve coating adhesion. Further research is needed to understand the long-term performance of the graphene-based coatings and reduce the uncertainty of the inventory.
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11.
  • Upadhyayula, Venkata Krishna Kumar, et al. (author)
  • Wind Turbine Blades Using Recycled Carbon Fibers : An Environmental Assessment
  • 2022
  • In: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 56:2, s. 1267-1277
  • Journal article (peer-reviewed)abstract
    • Polymers reinforced with virgin carbon fibers (VCF) are being used to make spar caps of wind turbine (WT) blades and polymers with glass fibers (GF) to make skins of the blade components. Here, we assess the life cycle environmental performance of the hybrid blades with spar caps based on VCF and the shells and shear webs based on RCF (recycled CF) composites (RCF-hybrid). The production of the WT blades and associated reinforced polymers is assumed to occur in Sweden, with their uses and end-of-life management in the European region. The functional unit is equivalent to three blades in an offshore WT with the market incumbent blades solely based on the GF composite or the hybrid option. The RCF-hybrid blades offer 12-89% better environmental performance in nine out of 10 impact categories and 6-26% better in six out of 10 impact categories. The RCF-hybrid blades exhibit optimum environmental performance when the VCF manufacturing facilities are equipped with pollution abatement systems including regenerative thermal oxidizers to reduce ammonia and hydrogen cyanide emissions; spar caps are made using VCF epoxy composites through pultrusion and resin infusion molding, and the blade scrap is mechanically recycled at the end of life. The energy and carbon payback times for the RCF-hybrid blades were found to be 5-13% lower than those of the market incumbents.
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