scholarly journals Development of Calculation Model of the Distribution of Protective Currents of Gas Pipeline Electrochemical Protection System in Permafrost Soils

2021 ◽  
Vol 133 (2) ◽  
pp. 50-54
Author(s):  
S. A. Shkulov ◽  
◽  
I. V. Shishkin ◽  
A. S. Kuzbozhev ◽  
I. N. Birillo ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Seasonal Changes ◽  
Homogeneous Model ◽  
Calculation Model ◽  
Electrochemical Protection ◽  
Grid Model ◽  
Permafrost Soils ◽  
Transition Resistance ◽  
Conduction Layer ◽  
Electrochemical Protection System

Clarification of parameters of the distribution of protective currents in permafrost soils is an urgent issue. The article describes a grid model of the soil, which differs from the generally accepted homogeneous model. Grid model of soil imitates various conditions of permafrost. Calculation model allows us to estimate parameters of the electrochemical protection of gas pipelines, taking into account the inequality of the parameters of the electrical conductivity of soils and also the transition resistance of the protective coating of the pipes along the length of the section. The model also makes it possible to estimate seasonal changes in the propagation conditions of protection currents due to periodic thawing and freezing of the soil in the conduction layer.

scholarly journals Electrical conductivity method (ECM) stratigraphic dating of the Byrd Station ice core, Antarctica

1994 ◽  
Vol 20 ◽  
pp. 115-120 ◽  
Author(s):  
C.U. Hammer ◽  
H.B. clausen ◽  
C.C. Langway
Keyword(s):  
Electrical Conductivity ◽  
Acid Concentration ◽  
Seasonal Changes ◽  
Ice Core ◽  
Strong Acid ◽  
Conductivity Method ◽  
Electrical Conductivity Method

A continuous ECM profile (strong acid concentration) has been measured along the 2191 m of ice core recovered at Byrd Station, Antarctica, in 1968. The ECM profile reveals continuous and systematic seasonal changes which are used for dating the ice core back to 50 000 bp. Hammer and others: ECM stratigraphic dating of Byrd Station ice core, Antarctica

scholarly journals Electrical conductivity method (ECM) stratigraphic dating of the Byrd Station ice core, Antarctica

1994 ◽  
Vol 20 ◽  
pp. 115-120 ◽  
Author(s):  
C.U. Hammer ◽  
H.B. clausen ◽  
C.C. Langway
Keyword(s):  
Electrical Conductivity ◽  
Acid Concentration ◽  
Seasonal Changes ◽  
Ice Core ◽  
Strong Acid ◽  
Conductivity Method ◽  
Electrical Conductivity Method

A continuous ECM profile (strong acid concentration) has been measured along the 2191 m of ice core recovered at Byrd Station, Antarctica, in 1968. The ECM profile reveals continuous and systematic seasonal changes which are used for dating the ice core back to 50 000 bp. Hammer and others: ECM stratigraphic dating of Byrd Station ice core, Antarctica

Evaluation of Singular Value Decomposition (SVD) Enhanced Upscaling in Reservoir Simulation

2020 ◽  
Author(s):  
Xu Zhou ◽  
Mayank Tyagi
Keyword(s):  
Reservoir Simulation ◽  
Homogeneous Model ◽  
Flow Simulation ◽  
Reservoir Modeling ◽  
Base Case ◽  
Fine Grid ◽  
Heterogeneous Model ◽  
Grid Model ◽  
Simulation Results ◽  
Simulation Time

Abstract Reservoir upscaling is an important step in reservoir modeling for converting highly detailed geological models to simulation grids. It substitutes a heterogeneous model that consists of high-resolution fine grid cells with a lower resolution reduced-dimension homogeneous model using averaging schemes. Its objective is to use a coarse grid model to represent a fine grid model, thus to reduce simulation time. The benefit of upscaling in reservoir simulation is that it efficiently saves simulation time, and effectively preserves key features of data for flow simulation. Singular Vector Decomposition (SVD) is a matrix decomposition method. It has been used for image processing and compressing. It has been proved to be capable of providing a good compression ratio, and effectively saves digital image storage space. SVD also has been used in noise suppression and signal enhancement. It has been shown to be effective in reducing noise components arising from both the sound sampling and delivery system. This study evaluates the effect of SVD in parameterization and upscaling for reservoir simulation. A two-phase flow reservoir model was created using data from the SPE tenth comparative solution project [1]. Simulation results show that SVD is valid in the parameterization of permeability values. The reconstructed permeability matrices using certain amount of singular values are good approximations of the original permeability values. Simulation results from SVD processed permeability values are similar to that using the original values. SVD is then applied on the upscaled permeability value to evaluate the effectiveness on upscaling. Simulation results were compared between the base case, upscaled case, and SVD upscaled case. The simulation results did not show a significant improvement in the accuracy of predicting oil production by applying SVD on the upscaled permeability values. It could be because the reconstructed permeability matrix has the same dimension before and after the SVD processing, thus the model accuracy and efficiency are not significantly improved. Future work includes adding more cases to further explore the effect of SVD on upscaling. The number of grid blocks may be increased, and more layers can be added to investigate whether SVD enhance upscaling for larger scale reservoir simulation models.

Calculation and Analysis of Electrical Field in Valve Side Winding of Converter Transformer

2011 ◽  
Vol 383-390 ◽  
pp. 4865-4870
Author(s):  
You Hua Gao ◽  
Guo Wei Liu ◽  
Xiao Ming Liu ◽  
Zeng Feng Lai
Keyword(s):  
Electrical Conductivity ◽  
Electric Field ◽  
High Voltage ◽  
Influence Factors ◽  
Calculation Model ◽  
Distribution Characteristics ◽  
Electrical Field ◽  
Dc Voltage ◽  
Voltage Polarity ◽  
Maximum Electric Field

The numerical calculation model with compound insulation of transient electrical field is established. The types of voltage applied on the valve side winding of the converter transformer are complicated and the insulation is more prominent. So the simplied calculation model of the valve side winding of the converter transformer is established. The distribution characteristics of electrical field of the valve side winding of the converter transformer is analyzed and electric field in different electrical conductivity and permittivity are calculated under AC high voltage, DC high voltage, AC superimposed DC voltage, polarity reversal voltage. Under all kinds of high voltages, the maximum electric field strength is calculated and analyzed. Some important influence factors for electrical field distribution are also discussed in this paper.

scholarly journals Environmental Study of Some Water Characteristics at Um-Al-Naaj Marsh, South of Iraq.

2011 ◽  
Vol 8 (1) ◽  
pp. 531-538
Author(s):  
Baghdad Science Journal
Keyword(s):  
Electrical Conductivity ◽  
Dissolved Oxygen ◽  
Seasonal Changes ◽  
Suspended Solids ◽  
Total Suspended Solids ◽  
Environmental Study ◽  
Light Penetration ◽  
Negative Effects ◽  
Water Characteristics ◽  
Water Ph

Um-Al-Naaj region in Al-Hawiezah Marsh, Southern Iraq was chosen to study the environmental variations of some water characteristics during 2008, seasonally. The results showed clear seasonal changes in values of some environmental variables (temperature, depth, light penetration, turbidity, total suspended solids, pH, dissolved oxygen, reactive phosphate, reactive nitrite, and reactive nitrate), while there were no clear seasonal changes in electrical conductivity and salinity values. In addition, high nutrients concentrations and light penetration were noted. Statistical analysis showed significant positive relationship between air and water temperature; electrical conductivity and salinity. Water turbidity was significantly affected by total suspended solids. On the other hand, some of the studied variables had significant negative effects (relative relationships) to each other, when water pH and dissolved oxygen were affected by temperature; total suspended solids and turbidity affected also light penetration.

scholarly journals Abundance and composition of Rotifera in an abandoned meander lake (Lago Amapá) in Rio Branco, Acre, Brazil

2004 ◽  
Vol 21 (2) ◽  
pp. 233-241 ◽  
Author(s):  
Erlei Cassiano Keppeler ◽  
Elsa Rodrigues Hardy
Keyword(s):  
Electrical Conductivity ◽  
Seasonal Changes ◽  
Environmental Variables ◽  
High Water ◽  
Water Levels ◽  
Water Phase ◽  
Seasonal Differences ◽  
Animal Group ◽  
Rotifer Community ◽  
Significant Difference

The rotifer community in Lago Amapá (abandoned meander lake of the Rio Acre floodplain) was investigated with respect to seasonal changes. Sampling was performed at three collection stations, generally weekly, during the dry season between May 8, 1997 and October 31, 1997, and during the rainy season between January 2, 1998 and February 24, 1998. The density and composition of rotifer species (48 taxons of rotifers) were determined, and their diversity and abundance were observed to be greater, respectively, at high-water and low-water. Anova was performed, by means of the F test, to test for seasonal differences in environmental variables and rotifers, showing that there was a highly statistically significant difference for pH and transparency (p < 0.01). Pearson's correlation was used to show that rotifer numbers during the low-water phase correlated negatively with electrical conductivity (r = -0.8824, p < 0.05) and during the high-water phase correlated negatively with depth (r = -0.7513, p < 0.05). Seasonal changes, caused by an increase in water levels and the low diversification of niches, influenced the composition and abundance of the animal group studied.

Application of anchor grounding devices in territories where there are permafrost soils

2021 ◽  
pp. 150-155
Author(s):  
A. V. Sidorov ◽  
A. L. Portnyagin
Keyword(s):  
Electrical Conductivity ◽  
Frost Heaving ◽  
Cold Regions ◽  
Grounding System ◽  
Permafrost Soils

The article identifies the factors that affect the electrical conductivity of the soil. The most common methods of implementation of the grounding system, used in cold regions in permafrost conditions, are considered. A new design of the anchor electrode has been developed to prevent the ejection of the ground rod due to the effect of frost heaving of the soil. This article aims to describe the factors that should be considered when planning a grounding system for permanent and temporary installations in regions where there are seasonal frosts and permafrost.

Removing Substrate Background in TEM Microanalysis

1974 ◽  
Vol 32 ◽  
pp. 568-569
Author(s):  
John C. Russ ◽  
Nicholas C. Barbi
Keyword(s):  
Electrical Conductivity ◽  
Rapid Growth ◽  
Organic Film ◽  
Absolute Concentration ◽  
Background Signal ◽  
X Ray ◽  
Elemental Concentrations ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
The Continuum

The rapid growth of interest in attaching energy-dispersive x-ray analysis systems to transmission electron microscopes has centered largely on microanalysis of biological specimens. These are frequently either embedded in plastic or supported by an organic film, which is of great importance as regards stability under the beam since it provides thermal and electrical conductivity from the specimen to the grid.Unfortunately, the supporting medium also produces continuum x-radiation or Bremsstrahlung, which is added to the x-ray spectrum from the sample. It is not difficult to separate the characteristic peaks from the elements in the specimen from the total continuum background, but sometimes it is also necessary to separate the continuum due to the sample from that due to the support. For instance, it is possible to compute relative elemental concentrations in the sample, without standards, based on the relative net characteristic elemental intensities without regard to background; but to calculate absolute concentration, it is necessary to use the background signal itself as a measure of the total excited specimen mass.

Macromolecular structures of biological specimens are not obscured by controlled osmium impregnation

1983 ◽  
Vol 41 ◽  
pp. 606-607
Author(s):  
Klaus-Ruediger Peters ◽  
Samuel A. Green
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Critical Point ◽  
Metal Films ◽  
High Magnification ◽  
Osmium Impregnation ◽  
Instrumental Resolution ◽  
20 Nm ◽  
Continuous Metal

High magnification imaging of macromolecules on metal coated biological specimens is limited only by wet preparation procedures since recently obtained instrumental resolution allows visualization of topographic structures as smal l as 1-2 nm. Details of such dimensions may be visualized if continuous metal films with a thickness of 2 nm or less are applied. Such thin films give sufficient contrast in TEM as well as in SEM (SE-I image mode). The requisite increase in electrical conductivity for SEM of biological specimens is achieved through the use of ligand mediated wet osmiuum impregnation of the specimen before critical point (CP) drying. A commonly used ligand is thiocarbohvdrazide (TCH), first introduced to TEM for en block staining of lipids and glvcomacromolecules with osmium black. Now TCH is also used for SEM. However, after ligand mediated osinification nonspecific osmium black precipitates were often found obscuring surface details with large diffuse aggregates or with dense particular deposits, 2-20 nm in size. Thus, only low magnification work was considered possible after TCH appl ication.

Spreading the Word: Seasonal Changes Mean New Opportunities for Media Coverage

ASHA Leader ◽  
2013 ◽  
Vol 18 (7) ◽  
Keyword(s):  
Media Coverage ◽  
Seasonal Changes ◽  
Swimming Pools

Summer kicking into high gear conjures images of swimming pools and barbeques. But before you book your beach house for the weekend, think about what the changing seasons can mean for you professionally.

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