Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Flow cell”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
NASA NTRS1985

Pre-flight report on cultured human embryonic kidney cell handling and cell electrophoresis. Prepared prior to continuous-flow electrophoretic separation experiments aboard space shuttle flight STS-8

Studies of the physical properties of continuous-flow zero-G electrophoretic separator (CFES) buffer, the electrokinetic properties of human erythrocytes in the CFES buffer, the electrokinetic properties of human embryonic kidney cells in the CFES buffer, and the viability and yield of human embryonc kidney cells subjected to flight handling procedures are discussed. In general, the procedure for cell handling and electrophoresis of HEK-8514 cells in 1st or 2nd passage on STS-8 is acceptable if executed properly. The CFES buffer has ionic strength that is barely compatible with cell viability and membrane stability, as seen in experiments with human erythrocytes and trypan-blue staining of human kidney cells. Cells suspended in 10% dialysed horse serum for 3 days in the cold appear to be more stable than freshly trypsinized cells. 10% horse serum appears to be superior to 5% horse serum for this purpose. The mean absolute raw mobility of HEK-8514 cells in CFES buffer at 6 degrees, conductivity 0.055 mmho/cm, is 1.1 to 1.4 um-cm/V-sec, with a range of nearly a whole mobility unit.

Todd, P. W.↗
NASA NTRS2010

Analysis of Photospheric Convection Cells with SDO/HMI

Supergranulation is a component of solar convection that assists in the outward transportation of internal energy. Supergranule cells are approximately 35 Mm across, have lifetimes on the order of a day and have divergent horizontal velocities of around 300 m/s, a factor of 10 higher than their central radial components. While they have been observed using Doppler methods for around half a century, their existence is also observed in other datasets such as magnetograms and Ca II K images. These datasets clearly show the influence of supergranulation on solar magnetism and how the local field is organized by the flows of supergranule cells. The Heliospheric and Magnetic Imager (HMI) aboard SDO is making fresh observations of convection phenomena at a higher cadence and a higher resolution that should make granular features visible. Granulation and supergranulation characteristics can now be compared within the same datasets, which may lead to further understanding of any mutual influences. The temporal and spatial enhancements of HMI will also reduce the noise level within studies of convection so that more detailed studies of their characteristics may be made. We present analyses of SDO/HMI Dopplergrams that provide new estimates of convection cell sizes, lifetimes, and velocity flows, as well as the rotation rates of the convection patterns across the solar disk. We make comparisons with previous data produced by MDI, as well as from data simulations.

Williams, Peter E.↗
DOE OSTI2025

Bridging the Gap Between Pure and Mixed-Gas Performance of Thin-Film Composite Membranes

This study examines the influence of cell design on mixed-gas testing with PolyActive™ TFC membranes, featuring pure-gas CO₂ permeance of 1700–3100 GPU, representative of state-of-the-art CO₂/N₂ separation membranes. By designing and 3D-printing a counter-current permeation cell with optimized flow efficiency, we achieved a 33–41% increase in mixed-gas CO₂ permeance compared to traditional cells. Additionally, a comparison of sweep-gas and vacuum permeation methods revealed that vacuum operation mitigates downstream polarization, enhancing mixed-gas CO₂ permeance by 41%. These results underscore the critical role of permeation cell design and testing methods in accurately evaluating membrane performance, with significant implications for scaling up TFC membranes and optimizing industrial processes.

3D printing↗
DOE OSTI2022

Hydrodynamic Effects on Biofilm Development and Recombinant Protein Expression

Hydrodynamics play an important role in the rate of cell attachment and nutrient and oxygen transfer, which can affect biofilm development and the level of recombinant protein production. In the present study, the effects of different flow conditions on the development of Escherichia coli biofilms and the expression of a model recombinant protein (enhanced green fluorescent protein, eGFP) were examined. Planktonic and biofilm cells were grown at two different flow rates in a recirculating flow cell system for 7 days: 255 and 128 L h−1 (corresponding to a Reynolds number of 4600 and 2300, respectively). The fluorometric analysis showed that the specific eGFP production was higher in biofilms than in planktonic cells under both hydrodynamic conditions (3-fold higher for 255 L h−1 and 2-fold higher for 128 L h−1). In the biofilm cells, the percentage of eGFP-expressing cells was on average 52% higher at a flow rate of 255 L h−1. Furthermore, a higher plasmid copy number (PCN) was obtained for the highest flow rate for both planktonic (244 PCN/cell versus 118 PCN/cell) and biofilm cells (43 PCN/cell versus 29 PCN/cell). The results suggested that higher flow velocities promoted eGFP expression in E. coli biofilms.

Soares, Alexandra↗
NASA NTRS1987

Heterogeneous chemical reaction of chlorine nitrate and water on sulfuric-acid surfaces at room temperature

The use of H2SO4 as a catalyst for aerosol production of chlorine compounds in the chemistry of the antarctic stratosphere was investigated in laboratory trials. The experiments involved the gas surface collision rate of a molecule on a given surface during its residence time in a Knudsen cell in molecular flow conditions. Chlorine nitrate gas was made to flow through a chamber exposed to a container holding a 95.6 pct H2SO4 solution. Gas leaving the cell was scanned with a mass spectrometer. A sticking coefficient of 0.00032 was found for the chlorine nitrate, a value five times that previously reported.

Rossi, Michel J.↗
NASA NTRS1985

Kidney cell electrophoresis, continuing task

Materials and procedures for microgravity electrophoresis of living human embryonic kidney cells were evaluated to provide ground support in the form of analytical cell electrophoresis and flow cytometry. Preflight culture media, electrophoresis buffer, fraction collection media, temperature profiles, and urokinase assay procedures were tested prior to flight. Electrophoretic mobility distributions of aliquots of the cell population to be fractionated in flight were obtained. Cells were prepared in suspension prior to flight in electrophoresis buffer and 10% calf serum. Electrophoretic separation proceeded in electrophoresis buffer without serum in the Continuous Flow Electrophoretic Separator, and fractions were collected into sample bags containing culture medium and concentrated serum. Fractions that yielded enough progeny cells were analyzed for morphology and electrophoretic mobility distributions. It is noted that the lowest mobility fraction studied produced higher mobility progeny while the other fractions produced progeny cells with mobilities related to the fractions from which they were collected.

Todd, P. W.↗
DOE OSTI2023

High-Throughput Electrochemical Characterization of Aqueous Organic Redox Flow Battery Active Material

The development of redox-active organics for flow batteries providing long discharge duration energy storage requires an accurate understanding of molecular lifetimes. Herein we report the development of a high-throughput setup for the cycling of redox flow batteries. Using common negolyte redox-active aqueous organics, we benchmark capacity fade rates and compare variations in measured cycling behavior of nominally identical volumetrically unbalanced compositionally symmetric cells. We propose figures of merit for consideration when cycling sets of identical cells, and compare three common electrochemical cycling protocols typically used in battery cycling: constant current, constant current followed by constant voltage, and constant voltage. Redox-active organics exhibiting either high or low capacity fade rates are employed in the cell cycling protocol comparison, with results analyzed from over 50 flow cells.

Electrochemistry↗
NASA NTRS1992

Calorimetric determination of the thermoneutral potential of Li/BCX and Li/SOCl2 cells

Results are presented of the calorimetric determination of the effective thermoneutral potential, Eetp, of Li/BCS and Li/SOCl2 cells in the temperature range 0-60 C through a continuous recording of the cell voltage, heat flow, and current. The average effective thermoneutral potential at 25 C was 4.0 and 3.84 V for BCX and Li/SOCl2 cells, respectively. Based on the classical approach, the reversible cell potential, Er, and temperature dependence of reversible cell potential, dEr/dT, for BCX cell were 3.74 V and -0.952 mV/K, respectively, and for Li/SOCl2, Er = 3.67 V and dEr/dT = 0.567 mV/K. The thermal polarization (Eetp-E1), where E1 is the load voltage, for both cells, showed that they are the most thermally efficient near 40 C. An overall reaction proposed for the BCX chemistry is supported by the calculated thermodynamic parameters.

Kalu, E. E.↗
NASA NTRS1979

Numerical simulation of turbulent flows with a three-dimensional vortex-in-cell method

A three-dimensional vortex-in-cell method has been developed for the evaluation of local flow fields due to a family of vortex filaments which employs the principles and architecture of a code developed for magnetic field evaluation in plasma simulations. The computational effort in the new method, as compared to 'vortex pushing' by direct Biot-Savarat interaction, increases directly, rather than quadratically, with the number of vortex elements. The method is well suited for studying large number of vortex filaments or rings and can be used for simulating continuous vorticity.

Buneman, O.↗
DOE OSTI2022

Measurement of Resistance, Porosity, and Water Contact Angle of Porous Transport Layers for Low-Temperature Electrolysis Technologies

The porous transport layer is an important component of low-temperature electrolysis devices, such as proton exchange membrane water electrolyzers or anion exchange membrane water electrolyzers. PTLs have significant influence on the cell performance as their bulk resistance can impact the ohmic resistance, their contact resistance can impact electrode performance, and their structure can impact the liquid flow to the cell, which could cause mass-transport losses. In order to improve cell performance, optimization of the PTL is critical. Standardized protocols should be utilized to adequately compare PTLs being developed from different institutions. This method will detail a standardized protocol for measuring the resistance of the PTL using a four-wire setup and will also detail a process for measuring the porosity and water contact angle of the PTL using capillary flow porometry.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Architecture-Based Control of Temperature Gradient-Driven Water Transport in Polymer Electrolyte Fuel Cells

Temperature gradients can move water within the porous media of a polymer electrolyte fuel cell through phase-change-induced (PCI) flow. It is critical to understand PCI flow so that control and distribution of water within a fuel cell can be accomplished. This work investigates the role of architecture, specifically anode land width, on overall cell water content and distribution in the through-plane direction. A specially-designed 4.8 cm 2 fuel cell with precise thermal boundary conditions was imaged with neutrons using two different anode flow field configurations. A new, non-dimensional thermal transport number was developed which quantifies the relative influence of PCI flow on cell water transport. It was found that anode lands larger than the cathode lands cause large thermal gradients that instigate net water flux from the cathode to the anode. An asymmetric configuration with larger anode lands was found to have large changes in water content that were strongly sensitive to cell operating conditions. The thermal transport number developed here enables deduction of the net flux condition based on operating conditions and architecture. This approach enables design of high-performance systems with balanced water management.

25 ENERGY STORAGE↗
NASA NTRS2019

Efficient and Robust Weighted Least-Squares Cell-Average Gradient Construction Methods for the Simulation of Scramjet Flows

The ability to solve the equations governing the hypersonic turbulent flow of a real gas on unstructured grids using a spatially-elliptic, 2nd-order accurate, cell-centered, finite-volume method has been recently implemented in the VULCAN-CFD code. The construction of cell-average gradients using a weighted linear least-squares method and the use of these gradients in the construction of the inviscid fluxes is the focus of this paper. A comparison of least-squares stencil construction methodologies is presented and approaches designed to minimize the number of cells used to augment/stabilize the least-squares stencil while preserving accuracy are explored. Due to our interest in hypersonic flow, a robust multidimensional cell-average gradient limiter procedure that is consistent with the stencil used to construct the cellaverage gradients is described. Canonical problems are computed to illustrate the challenges and investigate the accuracy, robustness and convergence behavior of the cell-average gradient methods on unstructured cell-centered finite-volume grids. Finally, thermally perfect, chemically frozen, Mach 7.8 turbulent flow of air through a scramjet engine flowpath is computed and compared with experimental data to demonstrate the robustness, accuracy and convergence behavior of the preferred gradient method for a realistic 3-D geometry on a non-hex-dominant grid.

White, Jeffery A.↗
DOE OSTI2024

Continuous Flow Photoelectrochemical Reactor with Gas Permeable Photocathode: Enhanced Photocurrent and Partial Current Density for CO 2 Reduction

Photoelectrochemical (PEC) CO 2 reduction using a photocathode is an attractive method for making valuable chemical products due to its simplicity and lower overpotential requirements. However, previous PEC processes have often been diffusion-limited leading to low production rates of the CO 2 reduction reaction, due to inefficient gas diffusion through the liquid electrolyte to the catalyst surface, particularly at high current densities. In this study, a gas-permeable photocathode in a continuous flow PEC reactor is incorporated, which facilitates the direct supply of CO 2 gas to the photocathode-electrolyte interface, unlike dark reaction-based flow reactors. This concept is demonstrated using Ag-TiO 2 on carbon paper, illuminated through a quartz window and flowing liquid electrolyte. CO 2 supply is managed via pressure and flow control on the non-illuminated side of the carbon paper. The photocurrent density is significantly influenced by the flow rates and pressure of CO 2 gas, and the electrolyte flow rates. Compared to the traditional H-cell, the continuous PEC flow reactor achieves ≈10-fold increase in CO faradaic efficiency, 30-fold increase in production rate and 16-fold increase in stability without catalyst modifications. This work provides essential insights into the design and application of continuous gas-liquid flow PEC reactor systems, highlighting their potential for other PEC reactions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1981

Stark effect spectrophone for continuous absorption spectra monitoring

A Stark effect spectrophone using a pulsed or continuous wave laser having a beam with one or more absorption lines of a constituent of an unknown gas is described. The laser beam is directed through windows of a closed cell while the unknown gas to be modified flows continuously through the cell between electric field plates disposed in the cell on opposite sides of the beam path through the cell. When the beam is pulsed, energy absorbed by the gas increases at each point along the beam path according to the spectral lines of the constituents of the gas for the particular field strengths at those points. The pressure measurement at each point during each pulse of energy yields a plot of absorption as a function of electric field for simultaneous detection of the gas constituents. Provision for signal averaging and modulation is included.

Kavaya, M. J.↗
DOE OSTI2022

Pre-combustion mercury removal with co-production of hydrogen via coal electrolysis

Here, pre-combustion mercury removal via coal electrolysis was performed and investigated on a bench-scale coal electrolytic cell (CEC) systemically, and factorial design was used to determine the effect of different operating conditions (coal particle size, operating temperature, operating cell voltage, and flow rate of slurry) on the percentage of mercury removal, percentage of ash removal, and dry heating value change. The results showed that the operating cell voltage, as well as the interaction between operating cell voltage and coal particle size, are significant factors in the percentage of mercury removal. There is no significant factor in the percentage of ash removal and the dry heating value change, but the coal could be purified while keeping the dry heating value almost constant after electrolysis. A co-product of hydrogen could be produced during coal electrolysis with 50% lower energy consumption compared with water electrolysis. Meanwhile, a mechanism for mercury removal in coal was proposed. The facts indicate that coal electrolysis is a promising method for pre-combustion mercury removal.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1987

Optimization of the lithium/thionyl chloride battery

The progress which has been made in modeling the lithium/thionyl chloride cell over the past year and proposed research for the coming year are discussed. A one-dimensional mathematical model for a lithium/thionyl chloride cell has been developed and used to investigate methods of improving cell performance. During the course of the work a problem was detected with the banded solver being used. It was replaced with one more reliable. Future work may take one of two directions. The one-dimensional model could be augmented to include additional features and to investigate in more detail the cell temperature behavior, or a simplified two-dimensional model for the spirally wound design of this battery could be developed to investigate the heat flow within the cell.

White, Ralph E.↗
NASA NTRS2006

Computational Analysis of the Effect of Porosity on Shock Cell Strength at Cruise

A computational flow field analysis is presented of the effect of core cowl porosity on shock cell strength for a modern separate flow nozzle at cruise conditions. The goal of this study was to identify the primary physical mechanisms by which the application of porosity can reduce shock cell strength and hence the broadband shock associated noise. The flow is simulated by solving the asymptotically steady, compressible, Reynoldsaveraged Navier-Stokes equations on a structured grid using an implicit, up-wind, flux-difference splitting finite volume scheme. The standard two-equation k - epsilon turbulence model with a linear stress representation is used with the addition of a eddy viscosity dependence on total temperature gradient normalized by local turbulence length scale. Specific issues addressed in this study were the optimal area required to weaken a shock impinging on the core cowl surface and the optimal level of porosity and placement of porous areas for reduction of the overall shock cell strength downstream. Two configurations of porosity were found to reduce downstream shock strength by approximately 50%.

Massey, Steven J.↗
NASA NTRS2004

Multisensor Instrument for Real-Time Biological Monitoring

The figure schematically depicts an instrumentation system, called a fiber optic-based integration system (FOBIS), that is undergoing development to enable real-time monitoring of fluid cell cultures, bioprocess flows, and the like. The FOBIS design combines a micro flow cytometer (MFC), a microphotometer (MP), and a fluorescence-spectrum- or binding-force-measuring micro-sensor (MS) in a single instrument that is capable of measuring multiple biological parameters simultaneously or sequentially. The fiber-optic-based integration system is so named because the MFC, the MP, and the MS are integrated into a single optical system that is coupled to light sources and photometric equipment via optical fibers. The optical coupling components also include a wavelength-division multiplexer and diffractive optical elements. The FOBIS includes a laserdiode- and fiber-optic-based optical trapping subsystem (optical tweezers ) with microphotometric and micro-sensing capabilities for noninvasive confinement and optical measurement of relevant parameters of a single cell or other particle. Some of the measurement techniques implemented together by the FOBIS have long been used separately to obtain basic understanding of the optical properties of individual cells and other organisms, the optical properties of populations of organisms, and the interrelationships among these properties, physiology of the organisms, and physical processes that govern the media that surround the organisms. For example, flow cytometry yields information on numerical concentrations, cross-sectional areas, and types of cells or other particles. Micro-sensing can be used to measure pH and concentrations of oxygen, carbon dioxide, glucose, metabolites, calcium, and antigens in a cell-culture fluid, thereby providing feedback that can be helpful in improving control over a bioprocess. Microphotometry (including measurements of scattering and fluorescence) can yield further information about optically trapped individual particles. In addition to the multifunctionality not previously available in a single biological monitoring system, the FOBIS offers advantages of low mass, sensitivity, accuracy, portability, low cost, compactness (the overall dimensions of the fully developed FOBIS sensor head are expected to be less than 1 by 1 by 2 cm), and immunity to electromagnetic interference at suboptical frequencies. FOBIS could be useful in a variety of laboratory and field settings in such diverse endeavors as medical, veterinary, and general biological research; medical and veterinary diagnosis monitoring of industrial bioprocesses; and analysis of biological contaminants in air, water, and food.

Zhang, Sean (Zhanxiang)↗