Data-domain correlation approach for joint hydrogeologic inversion of time-lapse hydrogeologic and geophysical data

Geophysics ◽  
2009 ◽  
Vol 74 (6) ◽  
pp. F127-F140 ◽  
Author(s):  
Timothy C. Johnson ◽  
Roelof J. Versteeg ◽  
Hai Huang ◽  
Partha S. Routh
Keyword(s):  
Parameter Estimation ◽  
Hydraulic Conductivity ◽  
Strong Correlation ◽  
Geophysical Methods ◽  
Time Lapse ◽  
Geophysical Data ◽  
Correlation Operator ◽  
Parameter Estimations ◽  
Lack Of Information ◽  
Information Gap

Inverse estimations of hydrogeologic properties often are highly uncertain because of the expense of collecting hydrogeologic data and the subsequent lack of information. Geophysical data potentially can help fill this information gap because geophysical methods can survey large areas remotely and relatively inexpensively. However, geophysical data are difficult to incorporate into hydrogeologic parameter estimations primarily because of a lack of knowledge concerning the petrophysical relationships between hydrogeologic and geophysical parameters. A method can be used that allows time-lapse geophysical data to be incorporated directly into a hydrogeologic parameter estimation when a strong correlation exists between changes in geophysical and hydrogeologic properties. This approach bypasses the need for an explicit petrophysical transform by formulating the geophysical part of the hydrogeologic inversion in terms of a data-domain correlation operator. A synthetic electrical resistivity monitoring application is used to estimate the hydraulic conductivity distribution. Including time-lapse resistivity data to supplement sparse hydrologic data appears to improve greatly the resolution of hydraulic conductivity in this case. More generally, the formulation and results suggest that geophysical monitoring data can be incorporated effectively into a hydrogeologic parameter estimation using a data-domain correlation operator, assuming a strong correlation exists between changes in hydrogeologic and geophysical properties.

Coupled hydrogeophysical inversion to identify non-Gaussian hydraulic conductivity field by jointly assimilating geochemical and time-lapse geophysical data

2019 ◽  
Vol 578 ◽  
pp. 124092 ◽  
Author(s):  
Xueyuan Kang ◽  
Xiaoqing Shi ◽  
André Revil ◽  
Zhendan Cao ◽  
Liangping Li ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Time Lapse ◽  
Geophysical Data ◽  
Non Gaussian

scholarly journals In vitro cytotoxicity of Aspilia pluriseta Schweinf. extract fractions

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Sospeter N. Njeru ◽  
Jackson M. Muema
Keyword(s):  
Biological Activities ◽  
Vero Cells ◽  
In Vitro Cytotoxicity ◽  
Root Extract ◽  
Lack Of Information ◽  
Information Gap ◽  
Diphenyltetrazolium Bromide ◽  
Potential Use

Abstract Objectives We and others have shown that Aspilia pluriseta is associated with various biological activities. However, there is a lack of information on its cytotoxicity. This has created an information gap about the safety of A. pluriseta extracts. As an extension to our recent publication on the antimicrobial activity and the phytochemical characterization of A. pluriseta root extracts, here we report on cytotoxicity of tested solvent fractions. We evaluated the potential cytotoxicity of these root extract fractions on Vero cell lines by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Results We show that all solvent extract fractions (except methanolic solvent fractions) had cytotoxic concentration values that killed 50% of the Vero cells (CC50) greater than 20 µg/mL and selectivity index (SI) greater than 1.0. Taken together, we demonstrate that, A. pluriseta extract fractions’ earlier reported bioactivities are within the acceptable cytotoxicity and selective index limits. This finding scientifically validates the potential use of A. pluriseta in the discovery of safe therapeutics agents.

Application of geophysical methods for the investigation of the large gravitational mass movement of Séchilienne, France

2005 ◽  
Vol 42 (4) ◽  
pp. 1105-1115 ◽  
Author(s):  
O Meric ◽  
S Garambois ◽  
D Jongmans ◽  
M Wathelet ◽  
J L Chatelain ◽  
...  
Keyword(s):  
Rock Mass ◽  
Mass Movement ◽  
Seismic Refraction ◽  
Geophysical Methods ◽  
Time Lapse ◽  
Gravitational Mass ◽  
Electrical Tomography ◽  
Refraction Tomography ◽  
Geophysical Surveys ◽  
Geophysical Techniques

Several geophysical techniques (electromagnetic profiling, electrical tomography, seismic refraction tomography, and spontaneous potential and seismic noise measurement) were applied in the investigation of the large gravitational mass movement of Séchilienne. France. The aim of this study was to test the ability of these methods to characterize and delineate the rock mass affected by this complex movement in mica schists, whose lateral and vertical limits are still uncertain. A major observation of this study is that all the zones strongly deformed (previously and at present) by the movement are characterized by high electrical resistivity values (>3 kΩ·m), in contrast to the undisturbed mass, which exhibits resistivity values between a few hundred and 1 kΩ·m. As shown by the surface observations and the seismic results, this resistivity increase is due to a high degree of fracturing associated with the creation of air-filled voids inside the mass. Other geophysical techniques were tested along a horizontal transect through the movement, and an outstanding coherency appeared between the geophysical anomalies and the displacement rate curve. These preliminary results illustrate the benefits of combined geophysical techniques for characterizing the rock mass involved in the movement. Results also suggest that monitoring the evolution of the rock mass movement with time-lapse geophysical surveys could be beneficial.Key words: gravitational movement, geophysical methods, Séchilienne.

scholarly journals Lack of Information on Intangible Assets in the Financial Statements and a Way to Manage It

2020 ◽  
Vol 7 (3) ◽  
pp. 26-37
Author(s):  
Ya. I. Ustinova
Keyword(s):  
Information Needs ◽  
Intangible Assets ◽  
Financial Statements ◽  
Logical Analysis ◽  
Methodological Framework ◽  
Negative Consequences ◽  
Lack Of Information ◽  
Information Gap ◽  
Information Requests

The article is devoted to the study of localization of the lack of information on intangible assets in traditional financial statements and the analysis of possible ways to manage it. The methodological framework of the research includes methods of comparative, logical analysis, typology and grouping, induction and deduction. The research resulted in ways and means of disclosing the external manifestations of this type of information gap in the reporting and their negative consequences. It also analyses the options for filling in this gap, first of all, by means of the report on intangible assets that complements the structure and contents of traditional statements, and its comparison with the information requests of the company’s stakeholders. The conclusion about the need to revise the concept of preparing and disclosing information about the company’s intangible assets in the financial statements is substantiated. The research can be used in developing the concept of accounting for intangible assets, which can ensure that the gap between the content of financial statements and the information needs of users is bridged.

scholarly journals How to fill the information gap: Open Access for the social sciences and humanities

2020 ◽  
Author(s):  
Elisabeth Ernst ◽  
Judith Schulte
Keyword(s):  
Social Sciences ◽  
Open Access ◽  
Interest Group ◽  
Scholarly Communication ◽  
European Research ◽  
Social Sciences And Humanities ◽  
Lack Of Information ◽  
Information Gap ◽  
Research Organizations ◽  
The Social

Researchers not actively seeking information about Open Access and scholars who are not actively informed by their institutions might be concerned about publishing Open Access due to lack of information. Questions such as “Why is Open Access necessary and what do I gain?”, “What happens to my rights as an author?”, and “Why was I not told about this discount before I paid the full APC from my project fund?” might come up. This workshop is directed at representatives of research organizations and universities (e.g. Open Access offices, project coordinators, and interested researchers) on the topic of helping researchers finding answers to these questions and advocating for Open Access in the humanities and social sciences. The workshop seeks to discuss aspects that have been identified by participants priorly as most pressing to discuss. We therefore invite all registered participants to fill in a short survey by 12 October 2020. For any questions, please don’t hesitate contacting Elisabeth Ernst and Judith Schulte ([email protected]) OPERAS is the European Research Infrastructure for open scholarly communication in the social sciences and humanities. Its Special Interest Group on “Advocacy” works on topics related to the communication and advocating of Open Access in the social sciences and humanities and of those disciplines.

scholarly journals Parameter Selection in the Parameter Estimation of Grade Transitions in a Polyethylene Plant

2015 ◽  
Vol 3 (1) ◽  
pp. 1
Author(s):  
Niklas Andersson ◽  
Per-Ola Larsson ◽  
Johan Åkesson ◽  
Niclas Carlsson ◽  
Staffan Skålén ◽  
...  
Keyword(s):  
Parameter Estimation ◽  
Steady State ◽  
State Parameter ◽  
Parameter Selection ◽  
Selection Algorithm ◽  
Parameter Estimations ◽  
Dynamic Case ◽  
Nominal Parameter ◽  
Best Parameter ◽  
Parameter Values

A polyethylene plant at Borealis AB is modelled in the Modelica language and considered for parameter estimations at grade transitions. Parameters have been estimated for both the steady-state and the dynamic case using the JModelica.org platform, which offers tools for steady-state parameter estimation and supports simulation with parameter sensitivies. The model contains 31 candidate parameters, giving a huge amount of possible parameter combinations. The best parameter sets have been chosen using a parameter-selection algorithm that identified parameter sets with poor numerical properties. The parameter-selection algorithm reduces the number of parameter sets that is necessary to explore. The steady-state differs from the dynamic case with respect to parameter selection. Validations of the parameter estimations in the dynamic case show a significant reduction in an objective value used to evaluate the quality of the solution from that of the nominal reference, where the nominal parameter values are used.

Borehole seismic methods for geologic CO2 storage monitoring

2021 ◽  
Vol 40 (6) ◽  
pp. 434-441
Author(s):  
Don White ◽  
Thomas M. Daley ◽  
Björn Paulsson ◽  
William Harbert
Keyword(s):  
Co2 Storage ◽  
Geophysical Methods ◽  
Time Lapse ◽  
Microseismic Monitoring ◽  
Seismic Methods ◽  
Geologic Co2 Storage ◽  
Subsurface Monitoring ◽  
Borehole Seismic ◽  
Time Lapse Imaging

Borehole geophysical methods are a key component of subsurface monitoring of geologic CO2 storage sites because boreholes form a locus where geophysical measurements can be compared directly with the controlling geology. Borehole seismic methods, including intrawell, crosswell, and surface-to-borehole acquisition, are useful for site characterization, surface seismic calibration, 2D/3D time-lapse imaging, and microseismic monitoring. Here, we review the most common applications of borehole seismic methods in the context of storage monitoring and consider the role that detailed geophysical simulations can play in answering questions that arise when designing monitoring plans. Case study examples are included from the multitude of CO2 monitoring projects that have demonstrated the utility of borehole seismic methods for this purpose over the last 20 years.

Geophysical research of the undefined on the surface of the medieval nacropolis Shekshovo-9 (Suzdal Opole)

2020 ◽  
pp. 3-15
Author(s):  
I. N. Modin ◽  
S. A. Erokhin ◽  
A. M. Krasnikova ◽  
I. G. Shorkunov ◽  
V. A. Shevchenko ◽  
...  
Keyword(s):  
Geophysical Methods ◽  
Main Idea ◽  
Geophysical Data ◽  
Geophysical Research ◽  
Soil Structures ◽  
Geophysical Study ◽  
Archaeological Objects

The problem of modern archeology is the study of monuments that are not expressed on the surface due to centuries of plowing. Using the example of a geophysical study of the Shekshovo 9 monument (Suzdal Opolie region), we consider the use of geophysical methods for mapping the structure of the necropolis. The main idea is to search and interpret archaeological objects in geophysical data as heterogeneities towards background geological and soil structures.

scholarly journals Insight into the influence of local streambed heterogeneity on hyporheic-zone flow characteristics

2020 ◽  
Vol 28 (8) ◽  
pp. 2697-2712
Author(s):  
Robert Earon ◽  
Joakim Riml ◽  
Liwen Wu ◽  
Bo Olofsson
Keyword(s):  
Surface Water ◽  
Hydraulic Conductivity ◽  
Penetration Depth ◽  
Hyporheic Zone ◽  
Flow Characteristics ◽  
Time Lapse ◽  
Hyporheic Exchange ◽  
Tracer Injection ◽  
Hyporheic Flow ◽  
Exchange Processes

AbstractInteraction between surface water and groundwater plays a fundamental role in influencing aquatic chemistry, where hyporheic exchange processes, distribution of flow paths and residence times within the hyporheic zone will influence the transport of mass and energy in the surface-water/groundwater system. Geomorphological conditions greatly influence hyporheic exchange, and heterogeneities such as rocks and clay lenses will be a key factor for delineating the hyporheic zone. Electrical resistivity tomography (ERT) and ground-penetrating radar (GPR) were used to investigate the streambed along a 6.3-m-long reach in order to characterise geological layering and distinct features which may influence parameters such as hydraulic conductivity. Time-lapse ERT measurements taken during a tracer injection demonstrated that geological features at the meter-scale played a determining role for the hyporheic flow field. The penetration depth of the tracer into the streambed sediment displayed a variable spatial pattern in areas where the presence of highly resistive anomalies was detected. In areas with more homogeneous sediments, the penetration depth was much more uniformly distributed than observed in more heterogeneous sections, demonstrating that ERT can play a vital role in identifying critical hydraulic features that may influence hyporheic exchange processes. Reciprocal ERT measurements linked variability and thus uncertainty in the modelled resistivity to the spatial locations, which also demonstrated larger variability in the tracer penetration depth, likely due to local heterogeneity in the hydraulic conductivity field.

THE INTERPRETATION OF GEOPHYSICAL DATA

Geophysics ◽  
1937 ◽  
Vol 2 (2) ◽  
pp. 95-113 ◽  
Author(s):  
Ludwig W. Blau
Keyword(s):  
Physical Properties ◽  
Geophysical Methods ◽  
Present Knowledge ◽  
Geophysical Data ◽  
Surface Mapping ◽  
Contour Maps ◽  
Physical Effects ◽  
Data Result ◽  
Geologic Information

Geophysical data result from measurements of physical properties. The geophysicist postulates certain possible physical causes of the observed effects. The geologist reasons from observed geologic effects to geologic causes. The difficulties confronting the interpretation of physical effects as reflected in geophysical data in terms of geologic causes are pointed out. The author takes the position that geophysical data must be worked up independently. A competent geophysicist‐geologist may combine geophysical and geologic information in the preparation of a report which will then, and only when this procedure is followed, include all present knowledge of the area under investigation. The requirement that geophysical data be immediately translatable into geologic language and furnish material for drawing geologic contour maps is shown to be incompatible with the nature of geophysical data. Attention is drawn to the changing geophysical scene and to the tendency to use geophysical methods after they have ceased to be adequate for the solution of prospecting problems. It is suggested that geology can aid geophysics principally through library reconnaissance and advance surface mapping. Geophysics has become a serious competitor of geology in the search for oil, and the geophysic‐geological ecotone has advanced steadily into geologic territory.

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