A5090247519- Fluid Dynamics and Turbulent Flows
- Advanced Numerical Analysis Techniques
- Fluid Dynamics and Heat Transfer
- Computational Geometry and Mesh Generation
- Electrohydrodynamics and Fluid Dynamics
- Heat Transfer Mechanisms
- Heat Transfer and Optimization
- Computer Graphics and Visualization Techniques
- 3D Shape Modeling and Analysis
- Electrowetting and Microfluidic Technologies
- Combustion and flame dynamics
- Heat Transfer and Boiling Studies
- Nanofluid Flow and Heat Transfer
- Turbomachinery Performance and Optimization
- Fluid Dynamics and Thin Films
- Physics of Superconductivity and Magnetism
- Fluid Dynamics and Mixing
- Particle Dynamics in Fluid Flows
- Microfluidic and Capillary Electrophoresis Applications
- Plant Surface Properties and Treatments
- Aerodynamics and Acoustics in Jet Flows
- Educational Games and Gamification
- Superconducting Materials and Applications
- Heat and Mass Transfer in Porous Media
- Solar Thermal and Photovoltaic Systems
University of Minnesota
2010-2024
University of Minnesota System
2022
Heat Transfer Research (United States)
2006-2021
Texas A&M University
2003-2020
Mitchell Institute
2002-2020
Indian Institute of Science Bangalore
1981-2020
Twin Cities Orthopedics
2020
University of California, Berkeley
2009-2012
University of Madras
2006-2010
Lawrence Berkeley National Laboratory
2009
Boiling is a common mechanism for liquid−vapor phase transition and widely exploited in power generation refrigeration devices systems. The efficacy of boiling heat transfer characterized by two parameters: (a) coefficient (HTC) or the thermal conductance; (b) critical flux (CHF) limit that demarcates from high HTC to very low HTC. While increasing CHF has significant impact on system-level energy efficiency, safety, cost, their values water other fluids have essentially remained unchanged...
Biporous media consisting of microscale pin fins separated by microchannels are examined as candidate structures for the evaporator wick a vapor chamber heat pipe. The fabricated out silicon using standard lithography and etching techniques. Pores which separate used to generate high capillary suction, while larger reduce overall flow resistance. transfer coefficient is found depend on area coverage liquid film with thickness order few microns near meniscus triple phase contact line. We...
In this work, results and data are reported on key aspects of sample processing protocols performed on-chip in a digital microfluidic lab-on-a-chip. We report the experiments processing, including preconcentration dilution, injection or dispensing, mixing. It is shown that high speed transport mixing analytes reagents can be using biological solutions without system contamination.
This paper presents four novel domain decomposition algorithms integrated with nonlinear mapping techniques to address collocation-based solutions of eigenvalue problems involving sharp interfaces or steep gradients. The proposed methods leverage the spectral accuracy Chebyshev polynomials while overcoming limitations existing tools like Chebfun, particularly in preserving higher-order derivative continuity and enabling flexible node clustering near discontinuities. Key findings include...
A microfluidic lab-on-chip (LoC) for measuring the concentration of human body metabolites, using submicroliter droplets as reaction chambers, is presented in this paper. The device based on manipulation principle electrowetting and integrated with an optical absorbance measurement system detection. We have demonstrated detection glucose a colorimetric enzyme-kinetic assay less than 40 seconds. sensor response linear range 25mg/dl to 300mg/dl, 5% deviation from linearity at upper limit. In...
Abstract In this paper we report a time‐resolved investigation of transients derived from curcumin, which may be intimately involved in the processes leading to its biological activity. Fluorescence and triplet quantum yields are respectively 0.06 0.11. The high percentage internal conversion is proposed proceed via H‐transfer within thermodynamically favored enol structure what formally 1,3‐diketone. energy (191 ± 2 kJ mol −1 ), natural lifetime (1.5 μs) self‐quenching rate constant (5.0 ×...
An on-chip dilution scheme for an electrowetting based microfluidic system is presented in this paper. The uses the mixing and splitting of two droplets different concentrations to result intermediate concentration, as fundamental operation. A range factors can be obtained repeating simple two-droplet cycles, various combinations. accuracy primarily depends on factors-variation droplet volume during dispensing splitting, homogenous mixing. proposed architecture was tested 2, 4 8, using a red...
Recent studies indicate that traditional instructional methods may not be as effective for the current and future generation of learners. Given increasing amounts time students spend playing video games, educators have been looking at using games to enhance teaching learning. Research indicates potential improve However there is lack empirical data on their effectiveness, particularly in a formal educational setting college level. In this paper we present preliminary results from pilot...
Mass transfer measurements on the endwall and blade suction surfaces are performed in a five-blade linear cascade with high-performance rotor profile. The effects of purge flow from wheelspace cavity entering hot gas path simulated by injecting naphthalene-free naphthalene-saturated air through slot upstream row at 45 deg to endwall, for Reynolds number 6×105 based true chord exit velocity, blowing ratios 0.5, 1, 1.5. Oil-dot visualization indicates that injection, recirculation region is...
Local mass transfer measurements were conducted on the tip of a turbine blade in five-blade linear cascade with blade-centered configuration. The clearance levels ranged from 0.6 to 6.9% chord. effect relative motion between casing and was simulated using moving endwall made neoprene mounted top wind tunnel. Data obtained for single Reynolds number 2.7×105 based exit velocity Pressure indicate that loading at 0.6% chord is reduce pressure gradients driving leakage flow. With introduction...
In the paper we describe design and development of a video game about sustainable energy use that effectively unites fun with learning. We also present results from an initial study educational impact game. Many games do not properly translate knowledge, facts, lessons into language games. This in are often neither engaging nor educational. Our approach differs by using mechanics to express content. The combines fantasy elements play conventions real-time strategy (RTS) genre numbers,...
Viscous linear stability calculations are presented for model low-density axisymmetric jet flows. Absolute growth transitions the column mode mapped out in a parametric space including velocity ratio, density Reynolds number, momentum thickness, and subtle differences between profiles. Strictly speaking, profiles used most studies to date only applicable unity Prandtl numbers zero pressure gradient flows—the present work relaxes this requirement. Results reveal how generally theory can...
Portable and automated field screening equipment would be very effective in detecting quantifying explosives at various sites. A droplet-based microfluidic lab-on-a-chip utilizing electrowetting is presented for the colorimetric detection of TNT (trinitrotoluene). The method uses reaction between nitroaromatics a strong base which forms highly colored Jackson-Meisenheimer complex. Microliter-sized droplets are programmed to transport, mix, react with potassium hydroxide (KOH) on chip....
Experiments conducted in helium axisymmetric jets with an annular coflowing air stream yield critical values of the velocity ratio U2∕U1 needed to suppress global instability inherent these low-density flows. Global mode suppression was achieved for velocities less than approximately 20% jet centerline velocity, though displayed a nonmonotonic relationship initial shear layer momentum thickness. The experiments are supported by spatio-temporal inviscid stability theory, where...