| 1. |
- Chilkoor, Govinda, et al.
(författare)
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Hexagonal Boron Nitride : The Thinnest Insulating Barrier to Microbial Corrosion
- 2018
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 12:3, s. 2242-2252
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Tidskriftsartikel (refereegranskat)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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| 2. |
- Das, Sujit, et al.
(författare)
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Vehicle lightweighting energy use impacts in U.S. light-duty vehicle fleet
- 2016
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Ingår i: Sustainable Materials and Technologies. - : Elsevier BV. - 2214-9937. ; 8, s. 5-13
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Tidskriftsartikel (refereegranskat)abstract
- In this article, we estimate the potential energy benefits of lightweighting the light-duty vehicle fleet from both vehicle manufacturing and use perspectives using plausible lightweight vehicle designs involving several alternative lightweight materials, low- and high-end estimates of vehicle manufacturing energy, conventional and alternative powertrains, and two different market penetration scenarios for alternative powertrain light-duty vehicles at the fleet level. Cumulative life cycle energy savings (through 2050) across the nine material scenarios based on the conventional powertrain in the U.S. vehicle fleet range from - 29 to 94 billion GJ, with the greatest savings achieved by multi-material vehicles that select different lightweight materials to meet specific design purposes. Lightweighting alternative-powertrain vehicles could produce significant energy savings in the U.S. vehicle fleet, although their improved powertrain efficiencies lessen the energy savings opportunities for lightweighting. A maximum level of cumulative energy savings of lightweighting the U.S. light-duty vehicle through 2050 is estimated to be 66.1billion GJ under the conventional-vehicle dominated business-as-usual penetration scenario. (C) 2016 Elsevier B.V. All rights reserved.
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| 3. |
- Islam, Jamil, et al.
(författare)
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Graphene as thinnest coating on copper electrodes in microbial methanol fuel cells
- 2023
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 17:1, s. 137-145
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Tidskriftsartikel (refereegranskat)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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| 4. |
- Oruganti, Raj Kumar, et al.
(författare)
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Artificial intelligence and machine learning tools for high-performance microalgal wastewater treatment and algal biorefinery : a critical review
- 2023
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Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 876
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Forskningsöversikt (refereegranskat)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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| 5. |
- Shanmugam, Kavitha, et al.
(författare)
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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
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Ingår i: ACS Sustainable Chemistry and Engineering. - : AMER CHEMICAL SOC. - 2168-0485. ; 7:5, s. 4951-4963
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Tidskriftsartikel (refereegranskat)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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| 6. |
- Shanmugam, Kavitha, et al.
(författare)
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Ecoefficiency of Thermal Insulation Sandwich Panels Based On Fly Ash Modified with Colloidal Mesoporous Silica
- 2019
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Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 7:24, s. 20000-20012
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Tidskriftsartikel (refereegranskat)abstract
- The current practice of landfilling fly ash generated by waste incineration is nonsustainable, so alternative ways of using this material are needed. Silanization effectively immobilizes the heavy metal contaminants in the incineration fly ash and enables its circular utilization because silanized fly ash (SFA) has market value as a low-cost filler for polymer composites. This study examines the ecoefficiency of a thermal insulation panel that consists of a polyurethane (PU) foam core sandwiched between two epoxy composite skins prepared by reinforcing glass fibers (GF) and SFA in epoxy resin. The ecoefficiency of such panels was evaluated by comparing their life cycle environmental externality costs (LCEE) to their life cycle costs (LCC). The LCEE was calculated by monetizing the panels’ environmental impacts, which were quantified by performing a life cycle assessment (LCA). The results revealed that the ecoefficiency of the composite panels is positive (47%) and superior to that of market incumbent alternatives with PU foam or rockwool cores and steel skins. The two market incumbents have negative ecoefficiencies, primarily due to their high LCEE. The environmental performance of the panel with SFA–GF epoxy composite skins can be further improved by using lignin-based epoxy resin or thermoplastic polypropylene as the polymer matrix of composite skins. Overall, application as a filler in fabricating polymer composite skins of sandwich panels is an upcycling pathway of SFA that combines circular economy prospects with sustainability benefits.
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| 7. |
- Shanmugam, Kavitha, et al.
(författare)
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Social Cost Benefit Analysis of Operating Compressed Biomethane (CBM) Transit Buses in Cities of Developing Nations : A Case Study
- 2019
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Ingår i: Sustainability. - : MDPI. - 2071-1050. ; 11:15
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Tidskriftsartikel (refereegranskat)abstract
- Cities in developing nations have to deal with two significant sustainability challenges amidst rampant urbanization. First, consumer-generated food waste is increasing monumentally since open dumping is still followed as a predominant practice, the negative environmental externalities associated with food waste disposal are growing beyond manageable proportions. Second, the dependency on conventional fuels like diesel to operate transit buses, which is one of the major causes for deteriorating urban air quality. A nexus established between food waste management and operation of transit buses can improve the sustainable performance of cities in developing nations. In this study, a Life Cycle Assessment (LCA) supported Social Cost-Benefit Analysis (SCBA) is performed by considering a hypothetical scenario of establishing a large food waste treating biomethanation plant in Mumbai, India. The food waste from the city is transported to a biomethanation plant where it is subjected to an anaerobic digestion (AD) process. The biogas produced as a byproduct is upgraded to compressed biomethane (CBM) and used as a vehicle fuel to operate transit buses within the city. The LCA results suggest that CBM buses can reduce greenhouse gas and particulate matter emissions by 60% compared to diesel or compressed natural gas (CNG) buses. Fossil depletion potential of CBM buses is 98% lower than diesel, suggesting CBM’s importance in decoupling developing nations dependency on imported crude oil. The SCBA considers: (a) costs to stakeholders, i.e., fees for open dumping of food waste and cost of fuel for operating transit buses; and (b) social costs incurred by negative environmental externalities (obtained by monetizing LCA results) resulting from both, open dumping as well as fuel combustion. SCBA results indicate that the food waste-based CBM model can save 6.86 billion Indian rupees (USD 99.4 million) annually for Mumbai. The savings are made due to a reduction in stakeholder’s costs (fuel) coupled with societal, i.e., environmental externality costs if entire transit bus fleet operates on CBM fuel instead of conventional fuel mix (33:67 diesel to CNG) currently used. Although the study is performed for Mumbai, the results will be replicable to any city of developing nations facing similar issues.
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| 8. |
- Shanmugam, Kavitha, et al.
(författare)
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Use of Liquefied Biomethane (LBM) as a Vehicle Fuel for Road Freight Transportation : A Case Study Evaluating Environmental Performance of Using LBM for Operation of Tractor Trailers
- 2018
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Ingår i: Procedia CIRP. - : Elsevier. - 2212-8271 .- 2212-8271. ; 69, s. 517-522
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Tidskriftsartikel (refereegranskat)abstract
- The environmental performance of Liquefied Biomethane (LBM) and Diesel operated Tractor Trailer (TT) is compared using the Life Cycle Assessment (LCA) study. In this study we consider, raw biogas produced from an anaerobic digestion process of a Wastewater Treatment Plant (WWTP) in Umea, Sweden, which is then upgraded and liquefied to LBM and used as a fuel for TTs. Currently, the WWTP in Umea is utilizing biogas, produced onsite for cogeneration of heat and electricity, thereby meeting its energy needs. A system expansion approach is applied where electricity and heat equivalent to amount of biogas displaced for LBM production is supplied from Swedish grid (SE) mix and incineration of wood chips respectively. Correspondingly, the biogas avoided for cogeneration of electricity and heat is accounted in the study. The equivalent functional unit chosen for the LCA study is “16,000,000 ton-km of a TT transporting products and goods”. The study is modelled using SimaPro LCA Software. The ReCiPe Midpoint (H) impact assessment methodology is used to quantify ten selected and relevant midpoint environmental impacts. When compared with Diesel TT system, LBM TT exhibits superior environmental performance in seven out of ten impact categories measured than the Diesel TT system. The highest reduction is seen in Global Warming Potential (GWP) and Fossil Depletion Potential (FDP) impacts thereby suggesting that LBM derived from raw biogas of WWTP an environmentally preferred alternative to diesel for operation of TTs. However, this value proposition can have other trade-offs such as increase in eutrophication and ecotoxicity impacts. Further, replacing diesel with LBM for TT operation may not have any significant environmental benefits when electricity is drawn from carbon intensive grid mixes (e.g. coal).
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| 9. |
- Upadhyayula, Venkata K.K., et al.
(författare)
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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
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Ingår i: Resources, Conservation and Recycling. - : Elsevier BV. - 0921-3449 .- 1879-0658. ; 133, s. 404-416
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Tidskriftsartikel (refereegranskat)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.
(författare)
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Lightweighting and electrification strategies for improving environmental performante of passenger cars in India by 2030 : A critical perspective based on life cycle assessment
- 2019
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Ingår i: Journal of Cleaner Production. - : Elsevier. - 0959-6526 .- 1879-1786. ; 209, s. 1604-1613
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Tidskriftsartikel (refereegranskat)abstract
- The Indian automotive industry is faced with an unenviable challenge of achieving a sustainable growth in one of the largest markets. Adapting to increasingly strict environmental norms by the government committed to reducing the national greenhouse gas emissions, growing concerns amongst the citizens over the deteriorating air quality in the cities are the major environmental sustainability challenges for the auto industry in next decade. In this study, we analyze the potential benefits of vehicle light weighting and introduction of electric vehicles through a cradle-to-grave life cycle assessment (LCA) of a standard sedan passenger vehicle. Based on the LCA results, five different scenarios are envisioned with different composition of the passenger vehicle fleet in 2030. These scenarios are used to analyze three key enviro-economical goals for India; (1) dependency on crude oil imports, (2) GHG emission reduction targets and (3) improvement in urban air quality. The results indicate that global warming potential (GWP) and fossil depletion impacts of ICEs can be reduced by 17%, while metal depletion reduces by 34% per vehicle with lightweighting. However, increase in freshwater ecotoxicity impact by 57% is one of the trade-offs. The GWP of a compact BEV powered with current (2014) and 2030 electricity grid mixes is 36% and 16% higher than petrol car. The GWP of a sub-compact BEV powered with current grid mix is 9% higher with current grid mix but 14% lower than petrol cars when powered with 2030 electricity grid mix. Crude oil consumption and GHG emissions are reduced by 20% with lightweight ICE fleet. Whereas, up to 45% reduction in crude oil consumption and 65% improvement in urban air quality can be achieved with BEV penetration scenarios. (C) 2018 Elsevier Ltd. All rights reserved.
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