scholarly journals Characterisation of transient electromagnetic signals during fixed interference sources in tunnel structure

2021 ◽  
Vol 18 (5) ◽  
pp. 6907-6925
Author(s):  
Wangping Qian ◽  
◽  
Yikang Xu ◽  
Zhenyuan Gu ◽  
Ziru Xiang ◽  
...  
Keyword(s):  
Response Curve ◽  
Electromagnetic Response ◽  
Superposition Method ◽  
Secondary Field ◽  
Response Curves ◽  
Transient Electromagnetic ◽  
Electromagnetic Signals ◽  
Multiple Field ◽  
Site Interpretation ◽  
Detection Effect

<abstract> <p>The detection effect of the transient electromagnetic method is ambiguous in engineering applications due to the existence of interference sources, so explaining the influence of these fixed interference sources on is crucial. In this paper, the response characterisation of transient electromagnetic signals of fixed interference sources are thoroughly investigated. First, the secondary field generated by these interference sources is analyzed, and a typical fixed interference source is calculated. Then, a sensitivity analysis of the transient electromagnetic response curve is carried out. Finally, the mathematical superposition method for multiple field sources is proposed and verified. The results illustrate that the transient electromagnetic response curve of uniform full-space surrounding rock with a single fixed interference source has an apparent lifting phenomenon in the middle stage and presents an approximate horizontal change rule at the late stage. The transient electromagnetic response curves of multiple field sources separately illustrate the response characterisation of different field sources at different time stages. These research results can provide a valuable reference for the on-site interpretation of detection signals.</p> </abstract>

scholarly journals Vehicle-Borne Transient Electromagnetic Numerical Characteristic Parameter of Water-Bearing Body behind Tunnel Linings

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Wangping Qian ◽  
Taiyue Qi ◽  
Xiao Liang ◽  
Shaojie Qin ◽  
Zongyang Li ◽  
...  
Keyword(s):  
Response Curve ◽  
Characteristic Parameter ◽  
Surrounding Rock ◽  
Electromagnetic Response ◽  
Numerical Characteristic ◽  
Characteristic Parameters ◽  
Response Curves ◽  
Technical Parameters ◽  
Transient Electromagnetic ◽  
First Time

The water-bearing body (WBB) behind tunnel linings has been some of the main causes of damage in operational tunnels. The WBB directly affects the serviceability state of tunnel linings; thus, determining a method to detect this problem is a widely studied issue regarding tunnel maintenance. In this paper, a vehicle-borne transient electromagnetic method (VBTEM) is put forward for the first time to detect WBB behind tunnel linings, and the aim is to fully investigate the transient electromagnetic response and numerical characteristics of the WBB behind tunnel linings. Firstly, the transient electromagnetic response curves of the WBB and surrounding rock are obtained and compared in detail by using the finite element method. Then, taking the distance, thickness, radius, and resistivity of the WBB as variable parameters, the parametric sensitivity rule of the response curve of the WBB is analyzed. Finally, a dimensionless response curve is proposed, a mathematical extraction equation is established, and seven numerical characteristic parameters are proposed and extracted. Based on seven numerical characteristic parameters, the technical parameters of the VBTEM equipment are put forward. The results illustrate that the transient electromagnetic response of the WBB is obviously different from that of surrounding rock. The seven numerical characteristic parameters of the dimensionless curve of the WBB can represent the entire response curve of the WBB. The results reveal that the first time gate of the VBTEM equipment needs to be less than 0.05 μs for short-distance problem, and the time span needs to reach four time spans at least. The research results can provide valuable technical references for the application of VBTEM.

The Calculation of 2.5D Transient Electromagnetic Response

2010 ◽  
Vol 36 ◽  
pp. 349-354
Author(s):  
Guo Hong Fu ◽  
Bin Xiong
Keyword(s):  
Differential Equation ◽  
Finite Element ◽  
Equation System ◽  
Background Field ◽  
Electromagnetic Response ◽  
Response Curves ◽  
Forward Algorithm ◽  
Element Mesh ◽  
Geoelectric Section ◽  
Transient Electromagnetic

A 2.5D finite element forward algorithm for TEM with block linear conductivity was put forward in this paper. Firstly, based on the Maxwell equations, 2-order dual differential equation along strike was obtained by Laplace and Fourier transform. Then finite element linear equation system was obtained from coupling differential equation by using the Galerkin method, and yields the numerical solution of 2.5D transient electromagnetic field. The conductivity in finite element mesh is linear but uniform. In addition, the total field is decomposed into background field and secondary field: the former is solved by analytical method, and the latter is calculated by numerical method. Finally, 2.5D transient electromagnetic response curves of several typical geoelectric section models were computed.

scholarly journals The application of multi-grounded source transient electromagnetic method in the detections of coal seam goafs in Gansu Province, China

2021 ◽  
Vol 18 (4) ◽  
pp. 515-528
Author(s):  
Kailiang Lu ◽  
Xiu Li ◽  
Ya'nan Fan ◽  
Jianmei Zhou ◽  
Zhipeng Qi ◽  
...  
Keyword(s):  
Coal Seam ◽  
Gansu Province ◽  
Electromagnetic Method ◽  
Electromagnetic Response ◽  
Transient Electromagnetic Method ◽  
Transient Electromagnetic ◽  
Electromagnetic Responses ◽  
Electromagnetic Methods ◽  
Engineering Designs ◽  
Electromagnetic Signals

Abstract Unknown coal seam goafs will pose various safety hazards in construction and engineering designs, thus the accurate detections of coal seam goafs have become engineering problems that urgently require effective solutions. Multi-grounded source transient electromagnetic methods have the advantages of large detection depths and the easy deployment of emission sources. Therefore, they can be used for explorations in such complex areas as mountains, lakes and swamps. Previously, grounded source transient electromagnetic methods had only one emission source arranged on the surface, and were relatively rarely used in field explorations with multi-grounded sources. This study analyses the electromagnetic response differences between multi-grounded sources and a single-grounded source. The results reveal that the electromagnetic responses of multi-grounded sources were larger. Transient electromagnetic signals were be targeted using combinations of multi-grounded sources, which successfully strengthened the detection abilities. As a result, this study was able to achieve the goals of increasing the detection depths and improving the ability to distinguish geological anomalies. In addition, this research investigation referred to the theory of implicit functions and used the z components of the decay voltage to calculate the apparent resistivity. Finally, the results of the field data of a coal goaf located in Gansu Province, China, showed that the applied multi-grounded sources transient electromagnetic method could obtain higher resolution in coal seam goaf resistivity distribution information.

Factor VII Clotting Assay: Influence of Different Thromboplastins and Factor VII-Deficient Plasmas

1991 ◽  
Vol 65 (02) ◽  
pp. 160-164 ◽  
Author(s):  
Marina Poggio ◽  
Armando Tripodi ◽  
Guglielmo Mariani ◽  
Pier Mannuccio Mannucci ◽  
Keyword(s):  
Heart Disease ◽  
Ischemic Heart Disease ◽  
Dose Response ◽  
Response Curve ◽  
Ischemic Heart ◽  
Factor Vii ◽  
Response Curves ◽  
Assay Sensitivity ◽  
Clinical Laboratories ◽  
Coagulant Activity

SummaryBeing a putative predictor of ischemic heart disease, the measurement of factor VII (FVTI) coagulant activity will be presumably requested to clinical laboratories with increasing frequency. To assess the influence on FVII assays of different thromboplastins and FVII-deficient plasmas we compared performances of all possible combinations of 5 thromboplastins and 6 deficient plasmas. The reproducibility of the clotting times of the dose-response curves for human and rabbit thromboplastins were acceptable (CV lower than 7%), whereas bovine thromboplastin had a higher CV. Reproducibility was very similar for all deficient plasmas when they were used in combination with a given thromboplastin. Responsiveness of the dose-response curve did not depend on the deficient plasma but rather on the thromboplastin: one rabbit thromboplastin was the least responsive, the bovine thromboplastin the most responsive, the human and the remaining two rabbit thromboplastins had intermediate responsiveness. Assay sensitivity to cold-activated FVII varied according to the thromboplastin: the bovine thromboplastin was the most sensitive, the human thromboplastin the least sensitive, of the three rabbit thromboplastins two were relatively sensitive, one was almost insensitive. In conclusion, our results indicate that thromboplastin rather than deficient plasma is the crucial factor in the standardization of FVII assay.

OVARIAN ASCORBIC ACID DEPLETION TEST FOR LUTEINIZING HORMONE

1967 ◽  
Vol 56 (4) ◽  
pp. 619-625 ◽  
Author(s):  
Hans Jacob Koed ◽  
Christian Hamburger
Keyword(s):  
Ascorbic Acid ◽  
Luteinizing Hormone ◽  
Dose Response ◽  
Response Curve ◽  
Dose Response Curve ◽  
Human Origin ◽  
Response Curves ◽  
Significant Difference ◽  
The Mean ◽  
Different Levels

ABSTRACT Comparison of the dose-response curves for LH of ovine origin (NIH-LH-S8) and of human origin (IRP-HMG-2) using the OAAD test showed a small, though statistically significant difference, the dose-response curve for LH of human origin being a little flatter. Two standard curves for ovine LH obtained with 14 months' interval, were parallel but at different levels of ovarian ascorbic acid. When the mean ascorbic acid depletions were calculated as percentages of the control levels, the two curves for NIH-LH-S8 were identical. The use of standards of human origin in the OAAD test for LH activity of human preparations is recommended.

Method for testing antiserum titer and avidity in nephelometric systems.

1981 ◽  
Vol 27 (11) ◽  
pp. 1838-1844 ◽  
Author(s):  
G A Hudson ◽  
R F Ritchie ◽  
J E Haddow
Keyword(s):  
Dose Response ◽  
Response Curve ◽  
Direct Evidence ◽  
Reaction Rates ◽  
Dose Response Curve ◽  
Antigen Concentration ◽  
Response Curves ◽  
Binding Strength ◽  
Antiserum Dilution ◽  
Antiserum Titer

Abstract Antiserum performance in a nephelometric system can be characterized by parameters derived from measuring reaction rates. The characterization process is derived from a series of dose-response curves (elicited nephelometric response vs antigen concentration) generated from various dilutions of the antiserum being tested. Antiserum titer can then be calculated by plotting the antigen concentration found at one-half the maximum nephelometric response (Hmax) of each dose-response curve (C50) vs the corresponding antiserum dilution. Antiserum avidity can be calculated by plotting Hmax against its corresponding antiserum concentration. After general expressions are determined for C50 and Hmax vs antiserum concentration, a single dose-response curve suffices for characterizing antisera with respect to titer and avidity. Direct evidence is provided for the validity of C50 and Hmax as measures of titer and avidity by correlating these parameters with antiserum binding strength and with the number of antibodies eluted from immobilized antigen. This method can be applied to evaluate and compare different antiserum lots having the same specificity, to identify reagent inadequacies by comparing antisera of different specificity, and to predict the optimal antiserum dilution to use in performing an assay.

2-D electromagnetic modeling by finite‐element method with a dipole source and topography

Geophysics ◽  
2000 ◽  
Vol 65 (2) ◽  
pp. 465-475 ◽  
Author(s):  
Yuji Mitsuhata
Keyword(s):  
Finite Element ◽  
Delta Function ◽  
Dipole Source ◽  
Electromagnetic Modeling ◽  
Secondary Field ◽  
Controlled Source ◽  
Transient Electromagnetic ◽  
Isoparametric Finite Element ◽  
Anomalous Bodies ◽  
Element Technique

I present a method for calculating frequency‐domain electromagnetic responses caused by a dipole source over a 2-D structure. In modeling controlled‐source electromagnetic data, it is usual to separate the electromagnetic field into a primary (background) and a secondary (scattered) field to avoid a source singularity, and only the secondary field caused by anomalous bodies is computed numerically. However, this conventional scheme is not effective for complex structures lacking a simple background structure. The present modeling method uses a pseudo‐delta function to distribute the dipole source current, and does not need the separation of the primary and the secondary field. In addition, the method employs an isoparametric finite‐element technique to represent realistic topography. Numerical experiments are used to validate the code. Finally, a simulation of a source overprint effect and the response of topography for the long‐offset transient electromagnetic and the controlled‐source magnetotelluric measurements is presented.

The harmonic and transient electromagnetic response of a thin dipping dike

Geophysics ◽  
1983 ◽  
Vol 48 (7) ◽  
pp. 934-952 ◽  
Author(s):  
P. Weidelt
Keyword(s):  
Formal Solution ◽  
Harmonic Excitation ◽  
Electromagnetic Response ◽  
Approximate Determination ◽  
Finite Conductivity ◽  
Circular Loop ◽  
Decay Modes ◽  
Transient Electromagnetic ◽  
Free Decay

An exact solution is given for the electromagnetic induction in a dipping dike of finite conductivity, represented as a thin half‐sheet in a nonconducting surrounding. The problem is formulated for arbitrary dipole or circular loop [Formula: see text] configurations. The formal solution obtained by the Wiener‐Hopf technique is cast into a rapidly convergent triple integral suitable for an effective numerical treatment. A good agreement is found between numerical results and analog measurements available for harmonic excitation. The transient response is obtained as a superposition of the half‐sheet free‐decay modes and is illustrated by some numerical examples for coincident loops, including a diagram for the approximate determination of conductance and depth of a vertical dike.

Oxytocin as an antidiuretic hormone. II. Role of V2 vasopressin receptor

1995 ◽  
Vol 269 (1) ◽  
pp. F78-F85 ◽  
Author(s):  
C. L. Chou ◽  
S. R. DiGiovanni ◽  
A. Luther ◽  
S. J. Lolait ◽  
M. A. Knepper
Keyword(s):  
Dose Response ◽  
Water Permeability ◽  
Response Curve ◽  
Collecting Duct ◽  
Oxytocin Receptor ◽  
Dose Response Curve ◽  
Vasopressin Receptor ◽  
Response Curves ◽  
V2 Receptor ◽  
V2 Vasopressin Receptor

We conducted this study to determine what receptor mediates the effect of oxytocin to increase osmotic water permeability (Pf) in the rat inner medullary collecting duct (IMCD). Reverse transcription-polymerase chain reaction (RT-PCR) experiments demonstrated that mRNA for both the oxytocin receptor and the V2 receptor is present in the rat terminal IMCD. In isolated perfused IMCD segments, we found that the V2 vasopressin receptor antagonist [d(CH2)5(1),D-Ile2,Ile4,Arg8]vasopressin, but not oxytocin receptor antagonists, blocked the hydrosmotic response to 200 pM oxytocin. The selective oxytocin receptor agonist [Thr4,Gly7]oxytocin did not increase water permeability. Oxytocin also increased urea permeability in IMCD segments. Studies in IMCD suspensions showed that oxytocin increases adenosine 3',5'-cyclic monophosphate production in a dose-dependent fashion with a half-maximal (EC50) response at 5.2 nM. The dose-response curves were virtually identical for IMCD suspensions from Sprague-Dawley rats and Brattleboro rats. The oxytocin dose-response curve was displaced to the right of the vasopressin dose-response curve (EC50, 0.44 nM). From these results, we conclude that the V2 receptor mediates the hydrosmotic action of oxytocin in rat IMCD.

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