Measurement of hydraulic conductivity in isolated arterioles of rat brain cortex

1993 ◽  
Vol 264 (6) ◽  
pp. H1788-H1797 ◽  
Author(s):  
M. Kimura ◽  
H. H. Dietrich ◽  
V. H. Huxley ◽  
D. R. Reichner ◽  
R. G. Dacey
Keyword(s):  
Hydraulic Conductivity ◽  
Rat Brain ◽  
Room Temperature ◽  
Applied Pressure ◽  
Unit Surface Area ◽  
Ph Change ◽  
Brain Vessels ◽  
Spontaneous Tone ◽  
Cerebral Arterioles ◽  
The Relationship

We have developed a new method for quantification of arteriolar hydraulic conductivity (Lp) from isolated rat brain vessels. The volume flux of water per unit surface area across the arteriole wall (Jv/S) was assessed from measurements of silicon oil drop movement within an occluded vessel at two to three pressures (between 20 and 70 mmHg); the Lp was derived from the slope of the relationship between Jv/S and applied pressure. Lp was measured in isolated cerebral arterioles 1) at room temperature (22 degrees C) without spontaneous vessel tone (control Lp; n = 11), 2) at room temperature with 10(-4) M adenosine (n = 5), and 3) at 37 degrees C with vessels dilated submaximally with 10(-4) M adenosine (n = 6). Lp at 22 degrees C without adenosine was 13.2 +/- 4.2 x 10(-9) (+/- SE) cm.s-1.cmH2O-1 for all vessels studied. Lp values ranged from 1.2 to 44.1 x 10(-9) cm.s-1.cmH2O-1 with a median value that was 5.9 x 10(-9) cm.s-1.cmH2O-1. Lp increased significantly (on average, 2.6-fold) with adenosine at 37 degrees C but not with adenosine at 22 degrees C. Control Lp bore no relationship to either the development of spontaneous tone or the diameter response to pH change, two recognized indicators of vessel viability.

Processing by Pulsed Laser Deposition and Structural, Morphological and Chemical Characterization of Bi-Pb-Sr-Ca-Cu-O and Bi-Pb-Sb-Sr-Ca-Cu-O Thin Films

2010 ◽  
Vol 75 ◽  
pp. 202-207
Author(s):  
Victor Ríos ◽  
Elvia Díaz-Valdés ◽  
Jorge Ricardo Aguilar ◽  
T.G. Kryshtab ◽  
Ciro Falcony
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Room Temperature ◽  
Pulsed Laser ◽  
Chemical Characterization ◽  
Laser Deposition ◽  
Nominal Composition ◽  
Deposition Parameters ◽  
The Relationship

Bi-Pb-Sr-Ca-Cu-O (BPSCCO) and Bi-Pb-Sb-Sr-Ca-Cu-O (BPSSCCO) thin films were grown on MgO single crystal substrates by pulsed laser deposition. The deposition was carried out at room temperature during 90 minutes. A Nd:YAG excimer laser ( = 355 nm) with a 2 J/pulse energy density operated at 30 Hz was used. The distance between the target and substrate was kept constant at 4,5 cm. Nominal composition of the targets was Bi1,6Pb0,4Sr2Ca2Cu3O and Bi1,6Pb0,4Sb0,1Sr2Ca2Cu3OSuperconducting targets were prepared following a state solid reaction. As-grown films were annealed at different conditions. As-grown and annealed films were characterized by XRD, FTIR, and SEM. The films were prepared applying an experimental design. The relationship among deposition parameters and their effect on the formation of superconducting Bi-system crystalline phases was studied.

GRAIN REFINEMENT AND MICROSTRUCTURE EVOLUTION IN ALUMINUM A2618 ALLOY BY HIGH-PRESSURE TORSION

2016 ◽  
Vol 78 (6-9) ◽  
Author(s):  
Intan Fadhlina Mohamed ◽  
Seungwon Lee ◽  
Kaveh Edalati ◽  
Zenji Horita ◽  
Shahrum Abdullah ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
High Pressure ◽  
Grain Refinement ◽  
Room Temperature ◽  
Rotation Speed ◽  
High Pressure Torsion ◽  
Applied Pressure ◽  
Saturation Level ◽  
Microstructural Refinement ◽  
Average Grain Size

This work presents a study related to the grain refinement of an aluminum A2618 alloy achieved by High-Pressure Torsion (HPT) known as a process of Severe Plastic Deformation (SPD). The HPT is conducted on disks of the alloy under an applied pressure of 6 GPa for 1 and 5 turns with a rotation speed of 1 rpm at room temperature. The HPT processing leads to microstructural refinement with an average grain size of ~250 nm at a saturation level after 5 turns. Gradual increases in hardness are observed from the beginning of straining up to a saturation level. This study thus suggests that hardening due to grain refinement is attained by the HPT processing of the A2618 alloy at room temperature.

Effects of Elevated Temperatures on the Compressive Strength of HFCC

2011 ◽  
Vol 261-263 ◽  
pp. 416-420 ◽  
Author(s):  
Fu Ping Jia ◽  
Heng Lin Lv ◽  
Yi Bing Sun ◽  
Bu Yu Cao ◽  
Shi Ning Ding
Keyword(s):  
Compressive Strength ◽  
Elevated Temperature ◽  
Fly Ash ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Relative Strength ◽  
Ordinary Concrete ◽  
Residual Compressive Strength ◽  
Fly Ash Concrete ◽  
The Relationship

This paper presents the results of elevated temperatures on the compressive of high fly ash content concrete (HFCC). The specimens were prepared with three different replacements of cement by fly ash 30%, 40% and 50% by mass and the residual compressive strength was tested after exposure to elevated temperature 250, 450, 550 and 650°C and room temperature respectively. The results showed that the compressive strength apparently decreased with the elevated temperature increased. The presence of fly ash was effective for improvement of the relative strength, which was the ratio of residual compressive strength after exposure to elevated temperature and ordinary concrete. The relative compressive strength of fly ash concrete was higher than those of ordinary concrete. Based on the experiments results, the alternating simulation formula to determine the relationship among relative strength, elevated temperature and fly ash replacement is developed by using regression of results, which provides the theoretical basis for the evaluation and repair of HFCC after elevated temperature.

Generation of Defects and Strain by Ion Implantation in Ge (100) Single Crystals, and in Pseudomorphic GexSi1-x Films Grown on Si (100)

1992 ◽  
Vol 262 ◽  
Author(s):  
D. Y. C. Lie ◽  
A. Vantomme ◽  
F. Eisen ◽  
M. -A. Nicolet ◽  
V. Arbet-Engels ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Single Crystals ◽  
Room Temperature ◽  
Defect Concentration ◽  
Double Crystal ◽  
X Ray ◽  
Positive Strain ◽  
Independent Coefficient ◽  
The Relationship ◽  
Si Ion Implantation

ABSTRACTWe have studied the damage and strain produced in Ge (100) single crystals by implantation of various doses of 300 keV 28Si ions at room temperature. The analyzing tools were x-ray double-crystal diffractometry, and MeV 4He channeling spectrometry. The damage induced by implantation produces positive strain in Ge (100). The maximum perpendicular strain and maximum defect concentration rise nonlinearly with increasing dose. These quantities are linearly related with a dose-independent coefficient of ∼ 0.013 for Ge (100) single crystals implanted at room temperature. The results are compared with those available for Si (100) self-implantation. We have also monitored the strain and defects generated in pseudomorphic Ge0.1Si0.9/Si (100) films induced by room temperature 28Si ion implantation. It is found that the relationship between the strain and defect concentration induced by ion implantation is no longer a simple linear one.

Synthesis of Self-Supporting ZnO Nanowire Array Film and its Optical Property and Room Temperature Ferromagnetism

2021 ◽  
Vol 1036 ◽  
pp. 45-52
Author(s):  
Jiao Yang ◽  
Xin Yu Wang ◽  
Peng Kai Li ◽  
Ji Fa Huang ◽  
Peng Hao Deng
Keyword(s):  
Exposure Time ◽  
Room Temperature ◽  
Surface Defects ◽  
Room Temperature Ferromagnetism ◽  
Nanowire Array ◽  
Nanowire Arrays ◽  
Zno Nanowire ◽  
Vertical Orientation ◽  
Vibration Sample Magnetometer ◽  
The Relationship

X-ray diffractometer, field emission scanning electron microscope (SEM, Hitachi S-4800), laser confocal micro-region Raman spectrometer and vibration sample magnetometer were used to systematically study the effects of polyethyleneimine concentrations and exposure time on the morphology and size of ZnO nanowire arrays. The photoelectric property and the relationship between the morphology of nanowire arrays and ferromagnetism at room temperature were also analyzed. Under 15 min exposure time, when the polyethyleneimine concentration is 2.25 g / L, the obtained ZnO nanowire array film exhibits the smallest size, the optimal density and vertical orientation. According to the study of luminescence and room temperature magnetism, it is shown that the optical and ferromagnetic property are related to the variation tendency of oxygen defects and surface defects of the ZnO nanowires.

scholarly journals Hydraulic Conductivity of Polymer-Amended Sand-Bentonite Backfills Permeated with Lead Nitrate Solutions

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Sheng-Qiang Shen ◽  
Ming-Li Wei
Keyword(s):  
Hydraulic Conductivity ◽  
Water Content ◽  
Applied Pressure ◽  
Lead Nitrate ◽  
Bound Water ◽  
Liquid Limit ◽  
Filter Press ◽  
Diffuse Double Layer ◽  
Comparison Results ◽  
Pb Concentration

Hydraulic conductivity of sand-bentonite (SB) backfills amended with polyanionic cellulose (PAC) to lead nitrate (Pb(NO3)2) solutions was evaluated experimentally in this study. PAC-amended sand-bentonite (PSB) backfills were synthesized by mixing sand-bentonite mixture with 0.3 to 1.2% dry PAC (by total dry mixture mass) and mixed with a certain weight of conventional bentonite (CB) slurry. The rheology properties including the filtrate loss, viscosity, density, and pH testes of slurry with various bentonite dosages were measured to determine the reasonable CB dosage of slurry. The slump tests on PSB backfills with various mass slurries were conducted to determine the corresponding water content of backfills with slump 125 ± 5 mm. Under the applied pressure 100 kPa, the hydraulic conductivity to Pb(NO3)2 solutions (kc) of PSB backfills with various PAC contents was evaluated based on the modified filter press (MFP) tests, to ascertain the optimum PAC content of PSB backfills when permeated with Pb(NO3)2 solutions. Index properties, including the specific gravity (Gs) and liquid limit (wL) of PSB backfills, were measured after MFP tests. The MFP tests for PSB backfills were then conducted under various applied pressures to obtain the relationship between void ratio (e) and hydraulic conductivity of backfills. Finally, the flexible-wall permeability test (FWP test) under osmotic pressure 100 kPa was conducted to verify the effectiveness of the MFP test. The results indicate that slurry with 8% bentonite dosage is the reasonable choice in slurry wall construction. PSB has lower GS and higher wL compared to SB; increasing Pb concentration leads to GS of PSB increased and wL of PSB decreased. PSB with 0.6% PAC content is supposed as the optimum proportion of backfills when permeated with concentrated Pb(NO3)2 solution. PAC adsorbs large amount of bound water, which leads to higher water content (w) and e of PSB backfills, while lead ions (Pb) cause the diffuse double layer (DDL) of bentonite compressed and e of PSB backfills reduced. The kc of PSB-0.6 remains lower than 10−9 m/s and increases less than 10 times though the Pb concentration was up to 500 mM, demonstrating that the hydraulic performance of backfills can be improved effectively in Pb(NO3)2 solution by the additive PAC. The comparison results between k from MFP tests and FWP tests show that the MFP test is an effective and easy evaluation of hydraulic conductivity of backfills.

The relationship between aggregation and other soil properties in cracking clay soils

Soil Research ◽  
1984 ◽  
Vol 22 (1) ◽  
pp. 59 ◽  
Author(s):  
KJ Coughlan ◽  
RJ Loch
Keyword(s):  
Hydraulic Conductivity ◽  
Salt Content ◽  
Chemical Properties ◽  
Aggregate Size ◽  
Strong Relationship ◽  
Clay Soils ◽  
Coarse Surface ◽  
Seedbed Preparation ◽  
The Relationship ◽  
Dispersion Ratio

This paper explores the processes responsible for clay dispersion, and the formation of large dry aggregates, in cracking clay soils. It also isolates the soil factors causing variations in dry aggregate size using regression analysis. Twelve cracking clay soil samples were selected on visual differences in dry aggregate size distribution following seedbed preparation, and a range of soil structural and chemical properties were measured. The per cent dry aggregates > 5 mm was found to increase with resistance to mechanical abrasion, stability to wet sieving after capillary wetting, and dispersion ratio, indicating that large dry aggregates are formed as a result of binding by dispersed clay. Both raindrop impact and puddling by cultivation may be involved in dispersion. There was a strong relationship between dry aggregate size in the 0-10 cm layer and salt content in the subsurface (60-90 cm) layer. Coarse surface aggregation is explained in terms of limited profile hydraulic conductivity. For the soils studied, the properties of the surface layer appear to be responsible, at least in part, for the limitation in profile hydraulic conductivity. Dry aggregate size in the 0-10 cm layer was not simply correlated with any of the chemical properties of that layer. However, equations containing two (ESP and CEC per gram of clay) or three (ESP, per cent clay and CEC) independent variables were derived to explain variations in dry aggregate size, both for the 12 soils studied and for a wider range of Queensland cracking clay soils.

scholarly journals Low Temperature Synthesis of Photocatalytic Mesoporous TiO2 Nanomaterials

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 893 ◽  
Author(s):  
Massimo Dell’Edera ◽  
Francesca Petronella ◽  
Alessandra Truppi ◽  
Leonarda Francesca Liotta ◽  
Nunzio Gallì ◽  
...  
Keyword(s):  
Thermal Treatment ◽  
Room Temperature ◽  
Mesoporous Tio2 ◽  
Aqueous Alkaline Solution ◽  
Tio2 Nanocrystals ◽  
Low Temperature Synthesis ◽  
Temperature Synthesis ◽  
Tio2 Nanomaterials ◽  
The Relationship ◽  
Tio2 Nanostructures

We report the synthesis of mesoporous TiO2 nanostructures based on the decomposition of TiOSO4 in aqueous alkaline solution at room temperature, followed by mild thermal treatment (110 °C) in an oven and suitable to yield up to 40 g of product per batch. The duration of the thermal treatment was found to be crucial to control crystalline phase composition, specific surface area, surface chemistry and, accordingly, the photocatalytic properties of the obtained TiO2 nanocrystals. The thorough investigation of the prepared samples allowed us to explain the relationship between the structure of the obtained nanoparticles and their photocatalytic behavior, that was tested in a model reaction. In addition, the advantage of the mild treatment against a harsher calcination at 450 °C was illustrated. The proposed approach represents a facile and sustainable route to promptly access an effective photocatalyst, thus holding a significant promise for the development of solutions suitable to real technological application in environmental depollution.

Modification in Texture of Magnesium by the Addition of Rare Earth Elements and its Influence on Mechanical Properties

2012 ◽  
Vol 736 ◽  
pp. 307-315 ◽  
Author(s):  
Murugavel Suresh ◽  
Satyam Suwas
Keyword(s):  
Mechanical Properties ◽  
Rare Earth ◽  
Magnesium Alloys ◽  
Aluminium Alloys ◽  
Room Temperature ◽  
Main Obstacle ◽  
Rare Earth Addition ◽  
Structural Applications ◽  
Re Elements ◽  
The Relationship

Mg alloys show limited room temperature formability compared to its lightweight counterpart aluminium alloys, which is a main obstacle in using this metal for most of the structural applications. However, it is known that grain refinement and texture control are the two possibilities for the improvement of formability of magnesium alloys. Amongst the approaches attempted for the texture weakening, additions through of rare-earth (RE) elements have been found most effective. The relationship between the texture and ductility is well established. In this paper, the effect of rare earth addition on texture weakening has been summarized for various magnesium alloys under the two most common modes of deformation methods.

scholarly journals Mpemba Effect- the Effect of Time

2021 ◽  
Author(s):  
Jianan Wang
Keyword(s):  
Gravitational Field ◽  
Surface Area ◽  
Time Effect ◽  
Light Quantum ◽  
Unit Surface Area ◽  
Heat Flows ◽  
Unit Surface ◽  
Average Wavelength ◽  
Nature Of Time ◽  
The Relationship

This paper draws the following conclusions on the nature of time by analyzing the relationship between time and speed, the relationship between time and gravitational field, the gravitational redshift of the photon, and the black-body radiation theorem: Time on an object is proportional to the amount of energy flowing out (or in) per unit time (observer’s time) per unit surface area of the object. When an object radiates energy outward: t'=μB(T) =μσT 4=μnhν/st Where t’ is the time on the object, μ is a constant, B(T) is the radiosity，the total energy radiated from the unit surface area of the object in unit time (observer’s time), σ is the Stefan-Boltzmann constant, T is the absolute temperature, n is the number of the photons radiated, ν is the average frequency of the photons radiated, s is the surface area of the object and t is the time on the observer. When the object radiates energy outward, the higher the energy density of the space (for example the stronger the gravitational field of the space), the smaller the radiosity B(T) of the object in the space, the longer the average wavelength of the light quantum emitted by the object, the slower the time on the object, the longer the life of the system. When the object radiates energy outward, the faster the object moves relative to the ether, the higher the energy density of the local space in which the object is located, the smaller the radiosity B(T) of the object, the longer the average wavelength of the light quantum radiated by the object, the slower the time on the object, and the longer the life of the system. When the object radiates energy outward, the higher the temperature of the object, the greater the object's radiosity B(T), the shorter the average wavelength of the light quantum radiated by the object, the faster the time on the object, and the shorter the life of the system. Applying the above conclusions about the nature of time, the author analyzes the Mpemba effect and the inverse Mpemba effect, and reaches the following conclusion: the Mpemba effect is the time effect produced when heat flows from objects into space, and the "inverse" Mpemba effect is the time effect produced when heat flows from space into objects.

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