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Showing 1 to 15 of 15 for “"back diffusion"”.
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Modeling of embedded flow fields and the effect of back-diffusion in electrochemical desalination
Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2027-05-01
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Modeling biotic and abiotic decay of trichloroethylene (TCE) using the Reactive Multi-Species Transport in 3-Dimensional Groundwater Aquifers (RT3D) code
… cleanup of a TCE contaminated site results from back diffusion. Back diffusion occurs when the TCE mass in the high permeability zones, HPZ, is removed and the TCE trapped in the low permeability zones, LPZ, of the heterogeneous aquifer diffuses out due to concentration gradient reversal and …
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Probing the influence of relative humidity and temperature on the sulfonated silica ceramic carbon electrode for PEM fuel cell operation
… that the SS-CCE cathode catalyst layer promotes back diffusion of water generated at the cathode to the anode resulting in an increased performance with temperature and low relative humidity. Moreover, the SS-CCE catalyst showed better stability after an accelerated stress test.
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A study of the effects of sucralfate in the bile duct litigated pig peptic ulcer model with particular reference to the effects on the physico-chemical properties of gastric mucus and including comparisons with famotidine and misoprostol
… mucus to increase the viscosity and retard the back diffusion of H+ ions. The work described in this dissertation set out to verify, in vivo, these claimed effects on mucus, using an experimental porcine model of peptic ulceration, the bile duct ligated pig. In addition, the effects of …
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Advancing Microbial Desalination Cell towards Practical Applications
… final desalinated water caused by contaminant back diffusion from the wastewater side can be theoretically explained by two mechanisms, Donnan exchange and molecule transport which are controlled by bioelectricity and concentration gradient. Scaling and fouling is also a factor needs to be …
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Hydraulic and Electrokinetic Delivery of Remediants for In-situ Remediation
… The second study aimed at alleviating back diffusion from low permeability porous media observed at numerous field studies. Experiments were conducted in a two-dimensional sandbox with alternate vertical layers of coarse sand and silt flooded with TCE at aqueous solubility. …
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Synthesis and Characterization of Sulfonated Poly(arylene ether sulfone)s for Membrane Separations
… particularly above about 80 C, results in back-diffusion of hydrogen across the membrane. This reduces efficiency, product purity, and long-term electrode stability. Hydrophilic-hydrophobic multiblock copolymers based on disulfonated and non-sulfonated poly(arylene ether sulfone) oligomers …
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Microdialysis to study the Gastrin-ECL cell Axis in the conscious rat
… mucosal damage is caused by ischemia and acid back diffusion. We also examined whether the vagus and the sympathetic nervous system contributes to the food- and gastrin-evoked responses of ECL cells in situ. The results suggest that vagal activation does not stimulate histamine mobilization by …
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Critical assessment of the MEDUSA gamma ray detection system for radon flux measurement on a tailings dam
… do not show seasonal variation and some have a back diffusion problem, and the time required for the result to be known is too long. For- example it takes several days for electrets to gather sufficient information required, yet it is a single point result. This makes it difficult to steer the …
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Application of experimental and computational fluid dynamics techniques to the design of vortex-amplifers
… Very little has been published in respect to back diffusion from VA's or the flow phenomena that cause it. The following work is an experimental and numerical investigation of the physics and characteristic behaviour of mini-V A's, resulting in the development of a potential retrofit mini-VA …
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Feedback Control of Ionic Polymer Actuators
… Physical phenomena like ionic motion, back diffusion of water and electrostatic force have been used to explain these models. This research demonstrates the use of feedback control to overcome the limitation of slow settling time. First, an empirical model of the ionic polymers …
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NONLINEAR AND ULTRAFAST OPTICAL STUDIES OF INTERFACIAL PROCESSES IN PHOTOVOLTAIC NANOMATERIALS
… band edge annihilation, the surface to bulk diffusion, and back diffusion from the bulk to the surface. A ca. 13 fs electron injection time is deduced for Ag to TiO2, which is faster than that generated in Au and dyes. Additionally, the excited state exciton dynamics of a porphyrin …
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Electrostatic control of microfluidic systems for enhancement of nanoparticle separations and FET nanobiosensors
… examined the possibility of modifying the salt background around a sensor. With the help of on-chip polarizable electrodes, we demonstrate a method for localized electronic desalting of a FET biosensor. By locally removing the excess ions that shield the device from analytes, the Debye length …
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Climatic Controls on the Porewater Chemistry of Mid-continental Wetlands
… from the near surface peat. I hypothesize that back-diffusion of groundwater-derived solutes from the peat matrix to active pore-spaces has allowed the geochemical signal from paleo-hydrogeologic discharge to persist into the current regime of dilute recharge. This effect promotes methane …
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INNOVATION AND OPTIMIZATION OF THE HYDROGEN TRANSPORT AND DISTRIBUTION CHAIN AS A GREEN AND RENEWABLE ENERGY VECTOR
… particularly in low-pressure regimes where back-diffusion can be mitigated more efficiently. Indeed, in low-pressure purification scenarios, optimized operation with Nafion® 212 decreased OPEX by 81% (from 2.34 € to 0.44 € per kg H2), despite higher CAPEX. For high-pressure scenarios, this …