جستجوی استاد راهنمای دانشگاهی

Laurent Demanetمشاهده پروفایل

استاد

• Inverse Problems
• Wave Propagation
• Geophysical Imaging
• +۱۱ مورد دیگر

Laurent Demanet is a Professor of Applied Mathematics at the Massachusetts Institute of Technology (MIT), with a primary appointment in the Department of Mathematics and a joint appointment in Earth, Atmospheric, and Planetary Sciences (EAPS). He served as Director of MIT’s Earth Resources Laboratory from 2018 to 2024, focusing on seismic imaging and wave propagation to visualize Earth's subsurface structures. Undergraduate: Mathematical Engineering and Theoretical Physics, Université de Louvain, Belgium PhD: Applied and Computational Mathematics, California Institute of Technology (Caltech), 2006 (advisor: Emmanuel Candès, William P. Carey Prize for best dissertation in mathematical sciences) Postdoctoral: Szegö Assistant Professorship, Stanford University (2006-2009) His research centers on applied mathematics and scientific computing for geophysics, particularly inverse problems, wave propagation, and signal processing. He develops numerical algorithms and machine learning tools to analyze indirect, incomplete, and noisy data, enabling accurate subsurface modeling for environmental monitoring, carbon sequestration, hydrogen storage, and geothermal energy. His work also addresses seismic hazards induced by resource exploration and storage activities. Scientific awards and honors include: National Science Foundation CAREER Award (2012) Alfred P. Sloan Research Fellowship (2011) Air Force Young Investigator Award (2011) MIT Class of 1954 Career Development Professorship (2013-2016) As Director of MIT’s Earth Resources Laboratory and through his research group, Demanet has advanced computational methods for geophysical imaging, mentored students, and secured grants for interdisciplinary projects. His work bridges applied mathematics, computational science, and geophysics to solve pressing environmental and energy challenges. He leads research on subsurface visualization, integrating machine learning and numerical algorithms to improve seismic imaging and quantify predictive uncertainty. His lab's applications span natural hazard assessment, resource management, and sustainable energy solutions.

Hauke Smidtمشاهده پروفایل

استاد

• Microbiology
• Environmental Microbiology
• Gut Microbiota
• +۴ مورد دیگر

Hauke Smidt is a Personal Professor at Wageningen University & Research, affiliated with the Molecular Ecology group within the Faculty of Veterinary Medicine and Animal Sciences. His research focuses on microbial ecology, particularly gut microbiota dynamics, antibiotic resistance, environmental microbiology, and the One Health framework. Smidt has supervised over 50 PhD students and contributed to 519 publications, including studies on microbiome resilience, fermented food impacts, and bioremediation strategies. Education and affiliations include leadership roles in projects addressing antimicrobial resistance, pig health, and drinking water microbiology. His work spans collaborations across Europe and Asia, with notable contributions to understanding microbial community responses to environmental stressors and dietary interventions. Smidt is actively involved in public outreach, as seen in media contributions discussing microbiome research and health benefits. Key projects include aquifer treatment for drinking water, microbiome simulation models, and combating plant pathogens. His awards and recognition are not explicitly listed, but his extensive publication record and project leadership highlight significant academic impact.

• Environmental Health Engineering
• Wastewater-Based Epidemiology
• Bioremediation
• +۷ مورد دیگر

Rolf Halden is a Professor and Center Director at Arizona State University, holding appointments in the School of Sustainable Engineering and the Built Environment, the Biodesign Center for Environmental Health Engineering, and the Global Futures Scientists and Scholars program. He is a leading expert in environmental health engineering, wastewater-based epidemiology, and bioremediation. Education: Ph.D. in Civil (Environmental) Engineering, University of Minnesota (1997) M.S. in Civil (Environmental) Engineering, University of Minnesota (1994) M.S. in Biology, Technical University of Braunschweig, Germany (1992) Postdoctoral Fellow, Environmental Science, Lawrence Livermore National Laboratory (1998) Research Focus: Halden’s research integrates environmental chemistry, public health, and sustainability to understand how anthropogenic chemicals affect ecological and human health. His lab uses advanced mass spectrometry (LC-MS/MS, MALDI-TOF) to track pollutants such as PPCPs, microplastics, pesticides, and dioxins across air, water, soil, and biological systems. He pioneered the use of wastewater treatment plants as public health observatories, enabling real-time tracking of disease, drug use, and environmental exposures. Scientific Awards & Recognition: Leadership Award, Arizona State University (2018) Rocky Mountain Emmy Award (2018) Leroy E. Burney Lecturer, Johns Hopkins School of Public Health (2011) ACS Expert Program Member (2014–present) NIEHS Superfund R01 Working Group National Leader (2012–2014) Labs & Teams: Halden is the Founding Director of the Biodesign Center for Environmental Health Engineering at ASU, where he leads a multidisciplinary team focused on environmental proteomics, bioremediation, and diagnostic tool development. He also co-leads the Human Health Observatory , a national wastewater monitoring network. Grants & Funding: Halden has secured major funding from NSF, NIH, EPA, DoD, and private industry. Notable projects include the development of in-situ groundwater monitoring devices, national wastewater surveillance of SARS-CoV-2, and studies on microplastics and neurodegenerative disease.

• Advanced water treatment processes
• Membrane processes
• Ozonation
• +۱۳ مورد دیگر

Prof. Dr. Jörg E. Drewes is a Full Professor and Chair at the Research Institute for Urban Water Management, Technical University of Munich (TUM), Germany. He also serves as Academic Program Director for Environmental Engineering at TUM and is a co-founder of Waterloop Solutions GmbH. His work spans advanced water treatment technologies, wastewater reuse, and environmental health surveillance. Affiliations : TUM, Colorado School of Mines, King Abdullah University of Science and Technology, UNSW Water Research Centre Research focuses on advanced oxidation processes , membrane fouling mitigation , micropollutant removal , and wastewater epidemiology for public health. His team develops integrated systems for water-energy-food nexus applications and graphene oxide-based treatment solutions. Recent publications address PFAS remediation , UVC-LED pre-treatment for biofouling control, and GIS-based wastewater surveillance models . Awards include the Bayerische Staatsmedaille (2023) and William Dunbar Medal (2022). 2023 : Bayerische Staatsmedaille 2022 : William Dunbar Medal 2018 : IWA Fellow He leads the Nexus@TUM initiative and contributes to EU water resilience strategies. Collaborations include projects in Germany, China, India, and Spain, focusing on climate-resilient water systems and resource recovery .

Diane E. Austinمشاهده پروفایل

استاد

• Human-Environment Interactions
• Environmental Justice
• Collaborative Research
• +۴ مورد دیگر

Diane E. Austin is a Professor and Director of the School of Anthropology at the University of Arizona. She also serves as a Research Anthropologist at the Bureau of Applied Research in Anthropology (BARA). Her work focuses on environmental anthropology, particularly community dynamics in industrial and environmental contexts, with a strong emphasis on social justice and collaborative research. She has over 25 years of experience leading interdisciplinary projects in the U.S., Mexico, and Gulf Coast regions. Austin's research spans diverse areas including Native American communities, U.S.-Mexico border sustainability, Gulf Coast oil industry impacts, and urban food systems in arid regions. She has pioneered long-term partnerships with tribal organizations, federal agencies, and community groups, earning recognition such as the University Distinguished Outreach Professor (2008) and Distinguished Director (2023). Her recent work highlights longitudinal studies on the Deepwater Horizon oil spill's social effects, binational environmental initiatives in Nogales, and community-based approaches to disaster resilience. She coordinates BARA's internship and post-baccalaureate programs, supporting hundreds of students in applied anthropological research. Awards: Partners in Conservation Award (2010), Border Research Partnership Award Finalist (2012) Leadership Roles: Chair of the Good Neighbor Environmental Board, Member of the Gulf Research Program Advisory Board Key Projects: Southern Paiute cultural preservation, Gulf Coast oil industry studies, Nogales reforestation initiatives Austin’s teaching includes courses on ethnographic methods, data analysis, and mixed-methods research. She actively engages in policy advocacy, contributing expert testimony in legal proceedings related to environmental disasters and labor rights.

Ram Rajagopalمشاهده پروفایل

دانشیار

• Smart Grids
• Renewable Energy Integration
• Power Systems Optimization
• +۳ مورد دیگر

Ram Rajagopal is an Associate Professor of Civil and Environmental Engineering and Electrical Engineering at Stanford University, and a Senior Fellow at the Precourt Institute for Energy. He leads the Stanford Sustainable Systems Lab (S3L), focusing on large-scale monitoring, data analytics, and stochastic control for infrastructure networks, particularly power systems. His research emphasizes renewable energy integration, smart distribution systems, and demand-side data analytics. Education: PhD in Electrical Engineering and Computer Sciences & MA in Statistics (UC Berkeley), MS in Electrical and Computer Engineering (UT Austin), and BEng in Electrical Engineering (Federal University of Rio de Janeiro). Research interests include power grid optimization, renewable energy systems, and data-driven approaches to infrastructure challenges. He has pioneered work in grid flexibility, distributed energy resources, and machine learning applications for energy systems. His lab develops technologies like Smart Dim Fuses and the EV-EcoSim platform for EV charging infrastructure optimization. Received NSF CAREER Award, Powell Foundation Fellowship, and Berkeley Regents Fellowship Over 30 patents and best paper awards Advises/founded companies in sensor networks, power systems, and data analytics Labs/Teams: Stanford Sustainable Systems Lab (S3L), Powernet Project. His work spans grid resilience, energy equity, and scalable energy solutions.

Peter A. Raymondمشاهده پروفایل

استاد

• Biogeochemistry
• Carbon Cycling
• Greenhouse Gas Exchange
• +۶ مورد دیگر

Peter A. Raymond is the Oastler Professor of Biogeochemistry at Yale University's School of the Environment and Department of Geology and Geophysics. He serves as Senior Associate Dean of Research & Director of Doctoral Studies and is Co-Director of the Yale Center for Natural Carbon Capture. Raymond leads the Raymond Biogeochemistry Lab, which investigates the biogeochemistry of inland waters, enhanced weathering, methane cycling, and blue carbon systems through cutting-edge field, laboratory, and modeling approaches. Education B.S., Marist College Ph.D., College of William and Mary/Virginia Institute of Marine Science Research Focus Raymond's research fundamentally reshapes our understanding of carbon cycling in aquatic systems, demonstrating that rivers serve as dynamic conduits rather than passive pipes in the global carbon cycle. His work examines how biology and watershed variables alter carbon chemistry in streams, rivers, and estuaries, with particular emphasis on understanding global carbon cycles in relation to climate change. Raymond employs radiocarbon measurements to explore the age and turnover of carbon in aquatic ecosystems, revealing that rivers are variable sources of both old and young terrestrial dissolved organic carbon to oceans. The Raymond Lab is particularly known for developing the Pulse-Shunt Concept, which challenges traditional views of riverine biogeochemistry by emphasizing the episodic and dynamic nature of elemental fluxes. Current research directions include enhanced weathering and alkalinity studies for carbon removal, global greenhouse gas budgets through projects like RECCAP 2, natural methane cycling in aquatic systems, and blue carbon ecosystems such as mangroves and salt marshes. Publication Trends Raymond's recent publications (2023-2025) demonstrate a strong focus on global carbon and methane cycling, with particular attention to inland water systems' role in the Earth's climate system. His work increasingly integrates large-scale datasets with field measurements to understand how climate change and human activities affect greenhouse gas emissions from rivers and streams. A significant portion of his recent work contributes to international efforts like the Global Carbon Project, aiming to refine estimates of global carbon and methane fluxes. His research also shows growing emphasis on carbon removal strategies, particularly enhanced rock weathering through the Earthshot-funded GOAL-A project, and their potential for climate mitigation. Scientific Recognition Fellow of the American Association for the Advancement of Science Member of the Connecticut Academy of Science and Engineering Coastal and Estuarine Research Federations Cronin Award for Young Scientists ISI highly cited author Past Editor and Chief of the American Geophysical Union's journal Global Biogeochemical Cycles Mentorship and Funding Professor Raymond currently mentors four doctoral students (Jon Gewirtzman, Shou-En "Samuel" Tsao, Benjamin Saalidong, and Mingyu Zhang) and masters student Bella Garrioch. His research is supported by multiple grants from the National Science Foundation (NSF), including CAREER awards, and participation in the Earthshot-funded GOAL-A (Global Ocean And Land Alkalinization) project. Raymond has also been involved in significant collaborative projects with USGS data to research how climate and land use change alter carbon export from US watersheds, and with Lamont Doherty to develop methods for measuring air-sea gas exchange of CO2 in rivers and estuaries. Research Infrastructure The Raymond Biogeochemistry Lab at Yale is a dynamic research group comprising research scientists, postdocs, doctoral and masters students, and postgraduate researchers. The lab recently acquired a Mini Carbon Dating System (MICADAS) at Yale, significantly expanding their research capabilities in ecosystem carbon turnover and verification of natural climate solutions. The lab collaborates globally on projects in the Arctic, Hudson River, and middle Atlantic Bight, and is actively involved in the NASA Carbon Monitoring System BlueFlux field campaign to assess carbon exchange in coastal wetlands.

Majid Ghayoomiمشاهده پروفایل

استاد

• Geotechnical Engineering
• Earthquake Engineering
• Unsaturated Soil Mechanics
• +۴ مورد دیگر

Majid Ghayoomi is a Professor and Civil Engineering Undergraduate Coordinator in the Department of Civil and Environmental Engineering at the University of New Hampshire's College of Engineering and Physical Sciences. His research focuses on geotechnical engineering and geomechanics, particularly unsaturated soil mechanics and geotechnical earthquake engineering. He teaches courses such as Soil Mechanics, Engineering Behavior of Soils, and Geotechnical Modeling. Dr. Ghayoomi holds a Ph.D. from the University of Colorado at Boulder, an M.S. from Sharif University, and a B.S. from the University of Tehran. His research interests include bioremediation, hazards mitigation, soil-structure interaction, and materials testing. He leads the Geotechnical Modeling and Innovation lab, advancing bio-inspired solutions and remote sensing applications in geotechnical systems. His recent work emphasizes climate change impacts on seismic resilience, microbial stabilization of soils, and satellite-based soil moisture monitoring. Key contributions include studies on liquefaction mitigation, seismic site response, and infrastructure vulnerability in dynamic environments. His research spans theoretical, experimental (centrifuge modeling), and computational approaches to address complex geotechnical challenges.

• Avian Ecology and Management
• Terrestrial and Aquatic Invertebrate Ecology
• Wetland Ecology and Assessment
• +۶ مورد دیگر

Craig Davis is a Professor and holds the Bollenbach Chair in Wildlife Management at Oklahoma State University's Department of Natural Resource Ecology & Management. He has been a faculty member since 2001, advancing from Assistant Professor (2001-2007) to Associate Professor (2007-2012), and has served as Bollenbach Chair since 2014. Davis earned his PhD in Wildlife Science from Texas Tech University (1996), an MS from Iowa State University (1991), and a BS from Ohio State University (1988). He is also a Certified Wildlife Biologist through The Wildlife Society. His research focuses on avian ecology, wetland restoration, and gamebird management, with specific interests in fire-grazing interactions, invertebrate communities, and climate change impacts on ecosystems. Key areas include grassland bird survival, wetland classification systems, and the effects of anthropogenic development on wildlife habitats. Davis actively collaborates with conservation organizations and agencies, addressing challenges like invasive species management and water infrastructure resilience. Teaching responsibilities include undergraduate courses on Wildlife Management Techniques and Wetland Ecology, as well as graduate courses like Advanced Wetland Ecology. His grants emphasize wetland restoration outreach, climate adaptation strategies, and studies on northern bobwhite and wild turkey populations. Notable projects include evaluating cellular transmission technology in wildlife monitoring and assessing the impact of extreme weather on gamebird survival. Grants (Selected): Expansion of potential wetland restoration opportunities in Oklahoma (2024-2027) Linking Research and Stakeholder Engagement for Wetland Conservation (2024-2026) Effects of Extreme Weather and Hunting on Northern Bobwhite (2023-2025) Research Themes: Aligns with UN Sustainable Development Goals 15 (Life on Land), 13 (Climate Action), 6 (Clean Water), 11 (Sustainable Cities), 14 (Life Below Water), and 9 (Industry/Infrastructure).

• Climate Change Adaptation
• Climate Services
• Drought Management
• +۳ مورد دیگر

Gregg M. Garfin is a Professor and Specialist in Climate, Natural Resources, and Policy at the University of Arizona’s School of Natural Resources and the Environment, and Deputy Director for Science Translation and Outreach at the Arizona Institute for Resilience. He holds a Ph.D. in Geosciences from the University of Arizona (2003), an M.S. in Geology and Geography from the University of Massachusetts (1997), and a B.S. in Geology and Geography from the same institution (1993). His work bridges science and societal decision-making, focusing on climate adaptation, drought management, and climate services. He directs the Water, Society, and Policy M.S. Program and has led interdisciplinary projects on climate resilience, including contributions to the Fourth National Climate Assessment. Roles: Professor, Deputy Director, Program Director Affiliations: Arizona Institute for Resilience, School of Natural Resources and the Environment Research Interests His research emphasizes climate adaptation strategies, climate policy, and the co-production of knowledge between scientists and decision-makers. Key areas include: Climate impacts on water resources and ecosystems Extreme heat and drought resilience in urban and border communities Climate change communication and education Awards & Recognition Garfin has received multiple accolades, including AAAS Fellowship (2020), University of Arizona Service Awards (2020, 2015), and the Global Initiative for Academic Networks (GIAN) Visiting Fellowship (2018). His work has been featured in peer-reviewed journals and media outlets, emphasizing actionable science for climate resilience. Grants & Contributions He has led federal and transnational projects, including binational climate resilience initiatives in the U.S.-Mexico border region and flood risk assessments in Seoul, South Korea. His work integrates participatory governance approaches to enhance community preparedness.

Neha Sharmaمشاهده پروفایل

استادیار

• Nutrient Recovery
• Electrochemical Resource Recovery
• Water Reuse
• +۲ مورد دیگر

Neha Sharma is an Assistant Professor in the Department of Civil and Environmental Engineering at Auburn University. Her research focuses on nutrient recovery, electrochemical resource recovery, water reuse, trace metal cycling, and pollutant fate and removal.

Elmira Hassanzadehمشاهده پروفایل

دانشیار

• Hydrology
• Water Resources Engineering
• Climate Change Impact Assessment
• +۴ مورد دیگر

Elmira Hassanzadeh is an Associate Professor at the Department of Civil, Geological and Mining Engineering , Polytechnique Montréal, with a focus on integrated water resource modeling and management under climate and anthropogenic changes. She is affiliated with the Global Institute for Water Security (University of Saskatchewan) and the Experimental and Digital Water Flow Engineering Group (GENIE EAU) . Education: PhD in Civil Engineering, University of Saskatchewan Postdoctoral Fellow, McGill University Research interests include climate change impact assessment, socio-hydrological modeling, stakeholder engagement in water management, and sustainable development of water systems in cold regions. Her work emphasizes decision-making under uncertainty and adaptive strategies for ungauged basins. Recent publications (2024–2020) span coastal flood hazard modeling, climate-driven hydrological changes in tropical and Canadian watersheds, evaluation of agricultural practices under warming climates, and integrated approaches to water quality and system dynamics. Keywords include Hydrology , Climate Change , Water Security , and Socio-Hydrology . Supervision: She has mentored 15+ graduate students in projects related to Lake Urmia, Saskatchewan River Basin, and climate adaptation in Africa and the Pacific.

Christopher Turbillمشاهده پروفایل

دانشیار

• ecophysiology
• thermoregulation
• energy expenditure
• +۷ مورد دیگر

Christopher Turbill is an Associate Professor in Animal Science at Western Sydney University's School of Science, where he maintains an active research program focused on animal physiological ecology. He is affiliated with the Hawkesbury Institute for the Environment and serves as a Principal Investigator on multiple research projects while accepting HDR candidates for supervision. PhD from University of New England (2006) Thesis: Thermoregulatory Ecology of Tree-roosting Bats Supervised by Prof. Fritz Geiser Postdoctoral fellowships from Austrian Science Fund and Australian Research Council (DECRA) Former ecologist with NSW Government Professor Turbill's research integrates thermal and metabolic physiology with behavioral ecology to understand animal-environment interactions. His work has revealed significant ecological consequences of controlled body temperature variation in mammals and birds, linking these processes with metabolic energy expenditure, activity patterns, and life-history strategies. He specializes in bat biology and investigates conflicts between human environmental change and animal conservation requirements. His research keywords include ecophysiology, thermoregulation, energy expenditure, life-history ecology, body temperature, torpor, hibernation, and wildlife conservation. Analysis of Turbill's recent publications reveals a strong focus on thermal biology and conservation physiology, particularly regarding bats and birds. His work examines how animals manage energy through torpor, respond to climate change through thermal regulation, and adapt to anthropogenic disturbances. The research spans field studies of flying-foxes, microbats, and passerine birds across Australian ecosystems, with increasing emphasis on conservation applications related to white-nose syndrome, fire impacts, and wind energy development. Turbill leads significant research projects including the Ecology of the eastern horseshoe bat and its sensitivity to fire impacts (2024-2027), Vulnerability of Australian bats to white-nose syndrome (2021-2026), and Torpor use and burrowing behaviour in an arid zone passerine (2024). His work attracts funding from diverse sources including the Australian Research Council, Department of Planning and Environment, and various conservation organizations. Professor Turbill directs the BatsLab research group, which maintains a virtual hub for bat research at Western Sydney University. His team employs advanced methodologies including thermal imaging, GPS tracking, and physiological monitoring to study animal responses to environmental challenges. Current work focuses on developing conservation interventions for heat-stressed flying-foxes and assessing vulnerabilities of Australian bat species to emerging diseases.

Eduardo Araralمشاهده پروفایل

دانشیار

• Public Policy
• Collective Action
• Institutional Analysis
• +۹ مورد دیگر

Eduardo Araral is an Associate Professor at the Lee Kuan Yew School of Public Policy, National University of Singapore. With over 30 years of experience in academia and government, he holds a PhD in Public Policy from Indiana University-Bloomington under Nobel Laureate Elinor Ostrom. His research focuses on collective action, institutions, and water governance, with publications in Nature Human Behaviour , Public Administration Review , and World Development . He has held fellowships at Stanford University and centers associated with Coase, Ostrom, and Stigler. Research Interests : Collective action, institutional analysis, water governance, digital technologies in public policy, political economy, and socio-ecological systems. Scientific Awards : Ostrom Prize for the Governance of the Commons, Fulbright PhD Scholarship, and Presidential Award for Outstanding Overseas Filipinos. Leadership Roles : Vice Dean for Research, Assistant Dean for Academic Affairs, and Co-Director of the Institute of Water Policy (2016-2022) at LKYSPP. Global Engagement : Advised 20+ international organizations including ADB, World Bank, UNDP, and Fortune 500 companies, while lecturing to 7,000+ government officials across 50+ countries.

Bradley D. Olsenمشاهده پروفایل

استاد

• Polymer Science
• Materials Engineering
• Soft Condensed Matter Physics
• +۴ مورد دیگر

Bradley D. Olsen is a full professor in the Department of Chemical Engineering at the Massachusetts Institute of Technology (MIT), where he leads research at the intersection of polymer science, soft matter physics, and bioengineering. His work focuses on designing materials for critical applications in biotechnology, hemostasis, and sustainable polymer development while advancing fundamental understanding of polymer network mechanics and self-assembly. Education: Ph.D. in Chemical Engineering, University of California Berkeley (2007) S.B. in Chemical Engineering, Massachusetts Institute of Technology (2003) Olsen's research spans protein-based materials, block copolymer phase behavior, and mechanochemical hydrogels. He has pioneered methods for quantifying polymer network topology, developing hemostatic nanoparticles, and creating bio-inspired materials for selective biomolecular transport and medical applications. His recent publications emphasize data-driven approaches to polymer characterization and educational outreach in materials science. Scientific Awards: American Physical Society (APS) Fellow (2023) Fulbright Amazonia Scholar (2023) Alexander and I. Michael Kasser Chair in Chemical Engineering (2021) ACS Macro Letters Young Investigator Award (2021) MIT Committed to Caring Honor (2019) AIChE Owens Corning Early Career Award (2019) APS Dillon Medal (2018) Kavli Emerging Leader in Chemistry (2017) ACS Polymer Division Fellow (2016) Camille Dreyfus-Teacher Scholar (2015) Alfred P. Sloan Research Fellow (2014) NSF Career Grant (2013) NIH Postdoctoral Fellowship (2008-2009) Hertz Fellow (2003-2007) Barry M. Goldwater Scholarship (2002) Olsen has received significant grant support including NSF Career (2013) and AFOSR (2012) awards. His teaching activities include innovative international outreach like the 2025 soccer-themed science camp in Brazil. The Olsen Group at MIT explores advanced materials with applications ranging from trauma care to sustainable polymers.