scholarly journals Deformation-Induced and Reaction-Enhanced Permeability in Metabasic Gneisses, Iona, Scotland: Controls and Scales of Retrograde Fluid Movement

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Tim J. Dempster ◽  
Allan D. Hollinsworth ◽  
Euan McIntosh ◽  
Shannon Edgar ◽  
John W. Faithfull ◽  
...  
Keyword(s):  
Fluid Pressure ◽  
Structural Features ◽  
Small Scale ◽  
Fluid Composition ◽  
Reaction Products ◽  
High Permeability ◽  
Fluid Removal ◽  
Reaction Fronts ◽  
Retrograde Reaction ◽  
Single Reaction

The spatial distribution of greenschist-facies retrograde reaction products in metabasic gneisses from Iona, western Scotland, has been investigated. The retrograde products may be broadly accounted for by a single reaction, but their different spatial and temporal development indicates that a series of reactions occur with significantly different scales of metasomatic transfer. After initial fluid influx linked to deformation-induced high permeability, reaction-enhanced permeability, coupled to cycling of fluid pressure during faulting, strongly controls the pervasive retrogression. Ca-plagioclase and pyroxene in the gneisses are replaced by albite and chlorite in pseudomorphic textures, and this is followed by localized epidotization of the albite. Two main generations of epidote are formed in the gneisses. Epidosite formation is associated with prominent zones of cataclasite indicating a strong link between faulting and fluid influx. In contrast, complete alteration of albite to epidote in the host metabasic gneisses is spatially complex, and areas of pervasive alteration may be constrained by both epidote-rich veins and cataclasites. In other instances, reaction fronts are unrelated to structural features. Volume changes associated with individual stages of the reaction history strongly control the localized distribution of epidote and the earlier more widespread development of chlorite and albite. Such behaviour contrasts with adjacent granitic gneisses where epidotization is restricted to local structural conduits. Many small-scale mineralized fractures with evidence of having previously contained fluids do not enhance the pervasive retrogression of the metabasic gneisses and represent conduits of fluid removal. Retrogression of these basement gneisses is dominated by a complex combination of reaction-enhanced and reaction-restricted permeability, kinetic controls on the nucleation of reaction products, changes in fluid composition buffered by the reactions, and periodic local migration of fluids associated with fault movements. This combination generates spatially complex patterns of epidotization that are limited by cation supply rather than fluid availability and alternations between focused and pervasive types of retrogression.

Charactervation of Adhesion in Thin-Film Materials by the Blister Test

1992 ◽  
Vol 276 ◽  
Author(s):  
Y Z. Chu ◽  
H. S. Jeong ◽  
R. C. White ◽  
C. J. Durning
Keyword(s):  
Fluid Pressure ◽  
Structural Features ◽  
Adhesion Energy ◽  
Pressure Data ◽  
Blister Test ◽  
Constant Rate ◽  
Polymer Metal ◽  
Metal Interfaces ◽  
Peel Tests ◽  
Microscopic Dynamic

ABSTRACTIn this work a blister test is applied to study the adhesion of thin films to substrates. In the blister test one injects a fluid at constant rate at the interface between the substrate and an overlayer to create a “blister”. The fluid pressure is measured as function of time. An analysis gives a reliable way of calculating the adhesion energy Ga. from the time-dependent pressure data. The method was applied to a variety of systems including polymer/polymer, polymer/silicon and polymer/metal interfaces. The results show that the test is very sensitive and is able to determine small adhesion energies inaccessible in conventional peel tests. This work demonstrates that the blister test provides a means of relating the mechanical strength of an interface to its microscopic dynamic and structural features.

scholarly journals Review on the Lymphatic Vessels in the Dental Pulp

Biology ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1257
Author(s):  
Kamila Wiśniewska ◽  
Zbigniew Rybak ◽  
Maria Szymonowicz ◽  
Piotr Kuropka ◽  
Maciej Dobrzyński
Keyword(s):  
Dental Pulp ◽  
Lymphatic System ◽  
Light And Electron Microscopy ◽  
Fluid Pressure ◽  
Lymphatic Vessels ◽  
Main Role ◽  
Reaction Products ◽  
Dental Tissues ◽  
Optical Electron ◽  
Antigen Antibody

Despite many studies, opinions on the lymphatic system of the teeth are still incompatible. Studies using light and electron microscopy and directly using methods such as a radioisotope (radionuclide) scan and interstitial fluid pressure measurement reported incomplete results. Immunohistochemistry (IHC) plays the main role in investigating presence of the lymphatic system in dental tissues. This method uses labeled antibodies against antigens typical of lymphatic vessels. The use of appropriate staining enables the detection of antigen-antibody reaction products using a light (optical), electron or fluorescence microscope. However, these studies do not show the system of vessels, their histologic structure under physiological conditions and inflammation as well as the lymphangiogenesis process in the dental pulp. Unfortunately, there is a lack of studies associating the presence of lymphatic vessels in the dental pulp with local lymphatic nodes or large vessels outside the tooth. In the scientific and research environment, the evaluation of the lymphatic system of the teeth is problematic because it is quite difficult to clearly distinguish lymphatic vessels from small blood vessels. Despite many indications of the presence of lymphatic vessels in the pulp chamber, this problem remains open and needs further research.

Mean Free Path of Gas Molecules in Organic Nanochannels Using Molecular Simulations

SPE Journal ◽  
2019 ◽  
Vol 24 (06) ◽  
pp. 2555-2573
Author(s):  
Seunghwan Baek ◽  
I.. Yucel Akkutlu
Keyword(s):  
Free Path ◽  
Average Length ◽  
Strong Dependence ◽  
Fluid Pressure ◽  
Molecular Simulations ◽  
Mean Free Path ◽  
Computational Method ◽  
Fluid Composition ◽  
Bulk Fluid ◽  
Gas Molecules

Summary A computational method using molecular–simulation data is introduced to estimate the average mean–free–path length of multicomponent hydrocarbon molecules in an organic nanochannel. Grand–canonical Monte Carlo (MC) simulation is used first to construct the equilibrium distribution of the gas molecules in the channel. These results show that the smaller the channel is, the denser the gas mixture becomes because of nanoconfinement effects. Capillary condensation occurs in the smaller channels. The fluid composition inside a channel becomes progressively heavier when the bulk–fluid pressure outside the nanopore is reduced and the lighter hydrocarbons leave the channel. The mean–free–path lengths of the confined molecules are computed using the trajectories of the molecules displaced over time in the equilibrium molecular–dynamics (MD) simulation. The average length of the confined molecules is estimated to be an order of magnitude smaller than the theoretical value. Further, the length does not show a strong dependence on the channel width and the pressure. Consequently, the predicted Knudsen–number value does not vary significantly, as anticipated by the kinetic theory of gases and by the molecular simulations of pure fluids. This invariance indicates that compositional change caused by nanoconfinement eliminates transition into other transport regimes where continuum mechanics is no longer valid.

scholarly journals βγ-Crystallination Endows a Novel Bacterial Glycoside Hydrolase 64 with Ca2+-Dependent Activity Modulation

2019 ◽  
Vol 201 (23) ◽  
Author(s):  
Bal Krishnan ◽  
Shanti Swaroop Srivastava ◽  
Venu Sankeshi ◽  
Rupsi Garg ◽  
Sudhakar Srivastava ◽  
...  
Keyword(s):  
Glycoside Hydrolase ◽  
Domain Architecture ◽  
Enzyme Reaction ◽  
Structural Features ◽  
Clostridium Beijerinckii ◽  
Biofuel Production ◽  
Carbohydrate Binding ◽  
Reaction Products ◽  
Vast Number ◽  
Content Type

ABSTRACT The prokaryotic βγ-crystallins are a large group of uncharacterized domains with Ca2+-binding motifs. We have observed that a vast number of these domains are found appended to other domains, in particular, the carbohydrate-active enzyme (CAZy) domains. To elucidate the functional significance of these prospective Ca2+ sensors in bacteria and this widespread domain association, we have studied one typical example from Clostridium beijerinckii, a bacterium known for its ability to produce acetone, butanol, and ethanol through fermentation of several carbohydrates. This novel glycoside hydrolase of family 64 (GH64), which we named glucanallin, is composed of a βγ-crystallin domain, a GH64 domain, and a carbohydrate-binding module 56 (CBM56). The substrates of GH64, β-1,3-glucans, are the targets for industrial biofuel production due to their plenitude. We have examined the Ca2+-binding properties of this protein, assayed its enzymatic activity, and analyzed the structural features of the β-1,3-glucanase domain through its high-resolution crystal structure. The reaction products resulting from the enzyme reaction of glucanallin reinforce the mixed nature of GH64 enzymes, in contrast to the prevailing notion of them being an exotype. Upon disabling Ca2+ binding and comparing different domain combinations, we demonstrate that the βγ-crystallin domain in glucanallin acts as a Ca2+ sensor and enhances the glycolytic activity of glucanallin through Ca2+ binding. We also compare the structural peculiarities of this new member of the GH64 family to two previously studied members. IMPORTANCE We have biochemically and structurally characterized a novel glucanase from the less studied GH64 family in a bacterium significant for fermentation of carbohydrates into biofuels. This enzyme displays a peculiar property of being distally modulated by Ca2+ via assistance from a neighboring βγ-crystallin domain, likely through changes in the domain interface. In addition, this enzyme is found to be optimized for functioning in an acidic environment, which is in line with the possibility of its involvement in biofuel production. Multiple occurrences of a similar domain architecture suggest that such a “βγ-crystallination”-mediated Ca2+ sensitivity may be widespread among bacterial proteins.

scholarly journals MaBμlS-2: high-precision microlensing modelling for the large-scale survey era

2020 ◽  
Vol 498 (2) ◽  
pp. 2196-2218
Author(s):  
David Specht ◽  
Eamonn Kerins ◽  
Supachai Awiphan ◽  
Annie C Robin
Keyword(s):  
Proper Motion ◽  
Time Scale ◽  
Large Scale ◽  
Near Infrared ◽  
Event Rate ◽  
Structural Features ◽  
Small Scale ◽  
Stellar Kinematics ◽  
Full Account ◽  
Space Telescope

ABSTRACT Galactic microlensing datasets now comprise in excess of 104 events and, with the advent of next-generation microlensing surveys that may be undertaken with facilities such as the Rubin Observatory (formerly LSST) and Roman Space Telescope (formerly WFIRST), this number will increase significantly. So too will the fraction of events with measurable higher order information, such as finite-source effects and lens–source relative proper motion. Analysing such data requires a more sophisticated Galactic microlens modelling approach. We present a new second-generation Manchester–Besançon Microlensing Simulator (MaBμlS-2), which uses a version of the Besançon population synthesis Galactic model that provides good agreement with stellar kinematics observed by the Hubble Space Telescope (HST) towards the bulge. MaBμlS-2 provides high-fidelity signal-to-noise limited maps of the microlensing optical depth, rate and average time-scale towards a 400 deg2 region of the Galactic bulge in several optical to near-infrared pass-bands. The maps take full account of the unresolved stellar background, as well as limb-darkened source profiles. Comparing MaBμlS-2 with the efficiency-corrected OGLE-IV 8000 event sample shows a much improved agreement over the previous version of MaBμlS and succeeds in matching even small-scale structural features in the OGLE-IV event rate map. However, evidence remains for a small underprediction of the event rate per source and overprediction of the time-scale. MaBμlS-2 is available online (www.mabuls.net, Specht & Kerins) to provide on-the-fly maps for user-supplied cuts in survey magnitude, event time-scale and relative proper motion.

Small Scale Reforming Separation Systems with Nanomembrane Reactors for Direct Fuel Cell Applications

2010 ◽  
Vol 12 ◽  
pp. 105-113 ◽  
Author(s):  
Savvas Vasileiadis ◽  
Zoe Ziaka
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Product Yield ◽  
Cell System ◽  
Membrane Reactors ◽  
Inorganic Membrane ◽  
Small Scale ◽  
Reaction Products ◽  
Molten Carbonate ◽  
Fuel Gas

Our recent communication focuses on small scale and nanoscale type engineering applications of alumina inorganic membrane reactors and reactor-permeator systems for the conversion of renewable and non-renewable hydrocarbons and methane rich streams into hydrogen rich gas for direct inner application and operation of fuel cell systems. This study elaborates on new nanomembrane reactors for the steam-methane/hydrocarbon reforming and water gas shift reactions, including work in the synthesis, manufacturing, modeling and operation of such microreaction systems. The projected small scale reactors, separators and overall reaction systems are of current significance in the area of multifunctional microreactor and nanoreactor design and operation in connection with the operation of fuel cells for transportation, stationary, and portable power generation applications. An added advantage of such systems is the reactive and separative operations of the fuel cell membrane-processor which are combined to convert the hydrocarbon with steam to valuable fuel gas for continuous fuel cell operation. Moreover, the nanomembrane systems under development have the unique characteristics to perform multiple operations per unit volume, such as to utilize beneficial equilibrium shift principles in reactant conversion and product yield through the removal of permselective species (i.e., hydrogen) via the inorganic membrane out of the conversion/reaction zone. In this way, improved hydrogen and product yields can be achieved which exceed the equilibrium calculated yields. Simultaneously, the reaction products, such as synthesis gas (i.e., H2, CO and CO2) at the reactor exit can be used as fuel in mostly solid oxide and molten carbonate fuel cells. The role of the alumina nanomembrane is also in the main conversion and upgrading sections of these feedstocks in order to overcome existing heat and mass transfer limitations and increase the overall efficiency of the microreactor-fuel cell system.

Design, Fabrication, and Experimental Validation of a Warm Hydroforming Test System

2015 ◽  
Vol 138 (4) ◽  
Author(s):  
Mevlüt Türköz ◽  
Hüseyin Selçuk Halkacı ◽  
Mehmet Halkacı ◽  
Murat Dilmeç ◽  
Semih Avcı ◽  
...  
Keyword(s):  
Fluid Pressure ◽  
Test System ◽  
Process Window ◽  
Small Scale ◽  
Production Test ◽  
Part Quality ◽  
Heating And Cooling ◽  
Warm Hydroforming ◽  
And Performance ◽  
First Time

In this study, a hydroforming system was designed, built, and experimentally validated to perform lab-scale warm hydromechanical deep drawing (WHDD) tests and small-scale industrial production with all necessary heating, cooling, control and sealing systems. This manuscript describes the detailed design and fabrication stages of a warm hydroforming test and production system for the first time. In addition, performance of each subsystem is validated through repeated production and/or test runs as well as through part quality measurements. The sealing at high temperatures, the proper insulation and isolation of the press frame from the tooling and synchronized control had to be overcome. Furthermore, in the designed system, the flange area can be heated up to 400 °C using induction heaters in the die and blank holders (BH), whereas the punch can be cooled down to temperatures of around 10 °C. Validation and performance tests were performed to characterize the capacity and limits of the system. As a result of these tests, the fluid pressure, the blank holder force (BHF), the punch position and speed were fine-tuned independent of each other and the desired temperature distribution on the sheet metal was obtained by the heating and cooling systems. Thus, an expanded optimal process window was obtained to enable all or either of increased production/test speed, reduced energy usage and time. Consequently, this study is expected to provide other researchers and manufacturers with a set of design and process guidelines to develop similar systems.

ICDP project Drilling the Eger Rift – present status and further plans

2020 ◽  
Author(s):  
Torsten Dahm ◽  
Tomas Fischer ◽  
Heiko Woith ◽  
Pavla Hrubcova ◽  
Josef Vicek ◽  
...  
Keyword(s):  
Border Region ◽  
Small Scale ◽  
Earthquake Swarms ◽  
Fluid Composition ◽  
Mass Spectrometers ◽  
Monitoring Wells ◽  
Eger Rift ◽  
The Status ◽  
Cheb Basin ◽  
Natural Laboratory

<p><span>Within the ICDP-Eger drilling project we are developing one of the most modern and comprehensive laboratories at depth worldwide to study the interrelations between the flow of mantle-derived fluids through the crust and their degassing at the surface, the occurrence and characteristics of crustal earthquake swarms, and the relation to the geo-biosphere. The Cheb basin located in the western Eger Rift at the Czech-German border provides an ideal natural laboratory for such a purpose. In October 2016 the ICDP proposal was accepted for complementing two existing shallow monitoring wells with five new, distributed, medium depth (<400 m) drill holes F3 and S1-S4. </span></p><p><span>The resulting natural laboratory at depth will comprise five drilling sites for studying above mentioned phenomena. The F1-F3 drillings form a unique facility of three wells at one site within an active CO<sub>2</sub> mofette of Hartou</span><span>šov </span><span>for continuous recordings of fluid composition and fluid flow rate, as well as for intermittent GeoBio fluid sampling. Drillings S1-S4 are planned for seismological monitoring to reach a new level of high-frequency, near source observations of earthquake swarms and related phenomena such as seismic noise and tremors generated by fluid movements. Instrumentation of the seismic wells S1-S3 will include 8-element geophone chains and a bottom-hole broadband sensor. The borehole sensors will be complemented at S1 by small-scale surface array of approximately 400 m diameter to obtain truly 3D-array configurations. If possible, broadband surface stations and other sensors will be added to each drill location. </span></p><p><span>So far, we have completed drillings at sites S1, S2 and S3, with depth of </span><span>402, 480 and 400 m. </span><span>The drilling of S4 is planned in 2020 at one of the recently discovered Maars at the Czech-German border region. Drilling F3 was completed in September 2019 at a depth of 239 m. It has reached several over-pressurized, CO</span><span>2 </span><span>bearing layers. The three boreholes have been connected by underground tubes system to the nearby field laboratory equipped by flowmeters and mass spectrometers allowing for long time precise monitoring of the degassing process. The S1 borehole (Landwust) will be instrumented in January 2020 by a test geophone chain allowing, along with the DAS fibre-optic cable installed behind the casing, to carry out a VSP measurement.</span></p><p><span>In our presentation we provide information on the status of drillings, sensor installation and plans for the complete monitoring and data handling concept.</span></p>

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