A5028856149- Atmospheric chemistry and aerosols
- Rheology and Fluid Dynamics Studies
- Surfactants and Colloidal Systems
- Fluid Dynamics and Heat Transfer
- Innovative Microfluidic and Catalytic Techniques Innovation
- Electrostatics and Colloid Interactions
- Atmospheric aerosols and clouds
- Surface Modification and Superhydrophobicity
- Pickering emulsions and particle stabilization
- Electrohydrodynamics and Fluid Dynamics
- Atmospheric Ozone and Climate
- Spectroscopy and Quantum Chemical Studies
- Air Quality Monitoring and Forecasting
- Fluid Dynamics and Turbulent Flows
- Particle Dynamics in Fluid Flows
- Nonlinear Dynamics and Pattern Formation
- nanoparticles nucleation surface interactions
- Fluid Dynamics and Thin Films
- Microfluidic and Bio-sensing Technologies
- Coagulation and Flocculation Studies
- Pancreatic function and diabetes
- Plant Surface Properties and Treatments
- Electrowetting and Microfluidic Technologies
- Microfluidic and Capillary Electrophoresis Applications
- Chemical and Physical Properties in Aqueous Solutions
University of Minnesota
2016-2025
Twin Cities Orthopedics
2018-2024
The Ohio State University
2024
University of Colorado Boulder
2024
Cooperative Institute for Research in Environmental Sciences
2024
University of Minnesota System
2015-2022
Minneapolis Institute of Arts
2015-2021
University of Bristol
2016
University of California, Davis
2011-2015
Quality Research
2010-2015
Acid-driven multiphase chemistry of isoprene epoxydiols (IEPOX), key oxidation products, with inorganic sulfate aerosol yields substantial amounts secondary organic (SOA) through the formation organosulfur compounds. The extent and implications inorganic-to-organic conversion, however, are unknown. In this article, we demonstrate that extensive consumption occurs, which increases IEPOX-to-inorganic concentration ratio (IEPOX/Sulfinorg), as determined by laboratory measurements....
Abstract Pancreatic islet transplantation can cure diabetes but requires accessible, high-quality islets in sufficient quantities. Cryopreservation could solve supply chain challenges by enabling quality-controlled banking and pooling of donor islets. Unfortunately, cryopreservation has not succeeded this objective, as it must simultaneously provide high recovery, viability, function scalability. Here, we achieve goal mouse, porcine, human stem cell (SC)-derived beta (SC-beta) comprehensive...
Measuring the acidity of atmospheric aerosols is critical, as many key multiphase chemical reactions involving are highly pH-dependent. These impact processes, such secondary organic aerosol (SOA) formation, that climate and health. However, determining pH particles, which have minute volumes (10–23–10–18 L), an analytical challenge due to nonconservative nature hydronium ion, particularly most measurements made offline or under vacuum, where water can be lost acid–base equilibria shifted....
A semiempirical model is presented that predicts surface tensions (σ) of aqueous electrolyte solutions and their mixtures, for concentrations ranging from infinitely dilute solution to molten salt. The requires, at most, only two temperature-dependent terms represent either pure solutions, or over the entire composition range. relationship was found coefficients equation σ = c(1) + c(2)T (where T (K) temperature) salts in ion valency radius, melting temperature, salt molar volume....
Atmospheric aerosol acidity is an important characteristic of aqueous particles, which has been linked to the formation secondary organic by catalyzing reactions oxidized compounds that have partitioned particle phase. However, difficult measure and traditionally estimated using indirect methods or assumptions based on composition. Ongoing disagreements between experiments thermodynamic models necessitate improved fundamental understanding pH ion behavior in high ionic strength atmospheric...
Direct comparison of diffusion coefficients and viscosities ternary component single aerosol particles levitated using optical tweezers.
Atmospheric aerosol acidity impacts key multiphase processes, such as acid-catalyzed reactions leading to secondary organic formation, which impact climate and human health. However, traditional indirect methods of estimating pH often disagree with thermodynamic model predictions, resulting in still being poorly understood the atmosphere. Herein, a recently developed method coupling Raman microspectroscopy extended Debye-Hückel activity calculations directly determine individual particles...
Abstract. Hygroscopicity data for 36 organic compounds, including amino acids, alcohols and sugars, are determined using a comparative kinetics electrodynamic balance (CK-EDB). The CK-EDB applies an electric field to trap-charged aqueous droplets in chamber with controlled temperature relative humidity (RH). dual micro dispenser set-up allows sequential trapping of probe sample accurate determination droplet water activities from 0.45 > 0.99. Here, we validate benchmark the homologous...
Measurements of the hygroscopic response aerosol and particle-to-gas partitioning semivolatile organic compounds are crucial for providing more accurate descriptions compositional size distributions atmospheric aerosol. Concurrent measurements particle composition (inferred from refractive index) reported here using optical tweezers to isolate probe individual droplets over extended timeframes. The shown allow retrievals component vapor pressures through examining correlated variations in...
Mass transfer between the gas and condensed phases in aerosols can be limited by slow bulk diffusion within viscous particles. During heterogeneous multiphase reactions of organic aerosol particles, it is necessary to consider interplay numerous mass processes how they are impacted viscosity, including partitioning kinetics semi-volatile reactants, water oxidants. To constrain kinetic models chemistry, measurements must provide information on as many observables possible. Here, ozonolysis...
Liquid–liquid emulsion systems are usually stabilized by additives, known as surfactants, which can be observed in various environments and applications such oily bilgewater, water-entrained diesel fuel, oil production, food processing, cosmetics, pharmaceuticals. One important factor that stabilizes emulsions is the lowered interfacial tension (IFT) between fluid phases due to inhibiting coalescence. Many studies have investigated surfactant transport behavior leads corresponding...
Adsorption isotherms have important practical applications, including in solution chemistry where they been used to model solvent and solute activities liquid mixtures at extreme concentrations, such as pure melts. The conventional Brunauer–Emmett–Teller (BET) Guggenheim–Anderson–de Boer (GAB) models are less successful for dilute solutions (high water activities), which most data available. In this work we extend these include arbitrary numbers of additional adsorbed monolayers and, using...
Coalescence of micrometer-scale droplets is impacted by several parameters, including droplet size, viscosities the two phases, velocity, angle approach, as well interfacial tension and surfactant coverage. The thinning dynamics films between coalescing can be particularly complex in presence surfactants, due to generation Marangoni stresses reduced film mobility. Here, a microfluidic hydrodynamic "Stokes" trap used gently steer surfactant-laden micrometer-sized at center cross-slot. Water...
Coupled partitioning, interfacial chemistry and autocatalysis are shown through experiments kinetic modeling to drive condensation reactions at the air/water interface.
Although aqueous microdroplets have been shown to exhibit enhanced chemical reactivity compared bulk solutions, mechanisms for these enhancements are not completely understood. Pyruvic acid (PA) is an abundant α-keto in aerosols, fogs, and clouds the atmosphere, its conjugate base, pyruvate, important intermediate several metabolic pathways. Utilizing situ micro-Raman spectroscopy as a probe, we investigated chemistry of PA within relative humidity (RH)- temperature-controlled...
Spatial and temporal frequency dynamics were experimentally tracked via flow visualization for Newtonian fluids as a function of the inner cylinder Reynolds number ( Re i ) in between concentric, independently rotating cylinders with radius ratio 0.912 an aspect 60.7. Eight transitions from laminar to turbulent characterized detail stationary outer cylinder, producing highly resolved space–time frequency–time plots wavy, modulated weakly states. A previously unreported early-modulated wavy...
Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation Cari S. Dutcher, Susan J. Muller; Effects of moderate elasticity on the stability co- counter-rotating Taylor–Couette flows. Rheol. 1 May 2013; 57 (3): 791–812. https://doi.org/10.1122/1.4798549 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex...
Small amounts of water can enter diesel fuel during usage, causing major damage and failure engine parts. Water is dispersed in as droplets stabilized by the presence surface-active compounds original mixture well additives, including lubricity improvers deposit control agents. Additives partition to fuel–water interface lower interfacial tension (IFT), decreasing ability coalesce separate from fuel. The standard coalescing filters capture emulsion depends on dynamic IFT, conventionally...
Dynamic interfacial tension of droplets with surfactants is measured and investigated to understand bilgewater emulsion stability.
Ice nucleating particles (INPs) in sea spray aerosols (SSAs) are critical estimating cloud radiative forcing and precipitation with implications climate change. Laboratory experiments simulating the ocean-atmosphere environment becoming increasingly popular for studying nature of INPs SSAs. Understanding ice characteristics bulk seawater surface microlayer (SSML) can provide valuable information about emitted Samples this study were collected from a waveflume during phytoplankton bloom...