bluuebunny/crossref_metadata_2025 huggingface dataset:
Renal Involvement in IgA Vasculitis; Possible Correlation with Positive Antiphospholipid Antibodies
Authors: Hassas Yeganeh Mehrnoush , Yaraghi Aye , Salehi Shima , Rahmani Khosro , Javadi Vadood , Shiari Reza , Hosseinzadeh Hamed
Published: December 2020

IgA vasculitis is a hypersensitivity vasculitis, which is usually self-limiting. Renal involvement is the most damaging long-term complication of IgA vasculitis, happening in 20% - 100% of cases. Some factors have been reported to be associated with renal involvement in IgA vasculitis; however, no biomarker has been proved as a risk factor for renal involvement and its severity yet. We followed 48 patients with a confirmed diagnosis of IgA vasculitis for six months. We checked these patients for renal involvement by microscopic urine examination. We checked aPL antibodies in all patients on admission and 12 weeks later. Urinalysis showed renal involvement in 14 of 48 patients with IgA vasculitis (29.16%). Antiphospholipid antibodies were positive in 9 patients with IgA vasculitis and renal involvement (9 out of 14, 64.28%), while they were positive in only six patients with IgA vasculitis without renal involvement (6 out of 34, 17.64%), showing a moderate correlation between positive aLP and renal involvement in patients with IgA vasculitis, with a kappa index of 0.457. Serum aPL antibodies, as a tool to predict renal involvement in IgA vasculitis, show a sensitivity of 64.3%, a specificity of 82.4%, PPV of 60.0%, and NPV of 84.8%, demonstrating that a positive serum aPL antibody can be used to positively predict the renal involvement, while a negative result is not strong enough to rule out future renal involvement.
Islamic Banking Performance: A Bibliometric Review
Authors: Buana Greget Kalla , Hudaefi Fahmi Ali , Caraka Rezzy Eko
Published: December 2020

Islamic banks (IBs) have been criticized as not being genuinely Islamic, and the methods in measuring their performances have been debatable. While the literature on IBs performance has been emerging, such studies precisely assess its recent development remains absent. Therefore, we aim to evaluate the development of scholarly articles that measure IBs’ performances. We employ bibliometric analysis and sample related articles from the Scopus database. We find that the development of IBs performance literature may be understood by 111 peer-reviewed journal articles, 4 conference papers, 1 book, and 1 book series. We analyze these materials based on publication sources, country and institution affiliation, keywords association, and cluster dendrogram. Our model that quantifies the keywords association and cluster dendrogram provides a novelty in assessing IBs performance literature development. Future studies may replicate our model to cluster and identify the keyword associations from the unstructured data sources.
Constructivism Theory: The Factors Affecting Students’ Academic Performance in Higher Education
Authors: Al-Rahmi ALI Mugahed
Published: December 2020

This paper aimed to use social media impact on student studies in higher education. Apart from enjoyment and academic purposes, many educational practices and processes have been influenced by social networks. This paper highlighted the use of media tools in higher education as well as indicates out some of the factors. Moreover, through a literature review of related articles, we aim to provide insights into the impacts of a social network on educational quality, actual use of social media, and performance impact in higher education. A questionnaire survey on constructivism was circulated among a total of 206 university students as the key method for collecting data. This research hypothesizes educational quality and actual social media use indicates a positive effect in education, all of which also hypothesizes constructivism for educational quality and actual social media that in turn improve students’ satisfaction, and performance impact. Moreover, all research findings were attained through a quantitative method using the Structural Equation Modeling (SEM-AMOS). Findings of this research to indicate a positive effects students on their academic through behavioral intention to utilize social media to actual social media use for teaching and learning on higher education. Moreover, the results mention the use of social media for learning purpose, as well as social media to enables the sharing of knowledge, discussions, and information to enhance students' learning activities, Further studies are recommended which universities educators should take this into consideration when planning their curricula; it comes to the inclusion of technology in the teaching process.
The Impact of the Lubricant Dose on the Reduction of Wear of QRO90 Steel Dies Used in the Forging Process of the Valve Forging Made of High-Nickel Steel
Authors: Dworzak Łukasz , Hawryluk Marek , Janik Marta
Published: December 2020

TThe paper presents the results of research on the influence of the settings of lubrication and cooling system parameters (solenoid valve opening time and lubricant feed pressure in terms of its quantity) in order to select the optimal lubricating conditions and thus reduce the wear of the dies used in the first forging operation of the valve forging made of high-nickel steel. Based on the observation of lubrication in the industrial process, it was found that a significant part of the lubricant fails to reach the die cavity, reaching the outside of it, which causes die wear due to seizure resulting from adhesion of the forging material to the tool surface, as well as high lubricant consumption and dirt in the press chamber. The authors proposed their own mobile lubricating and cooling system, which allows for a wide range of adjustments and provided with automatic cleaning procedures of the entire system, unlike the fixed lubrication system used so far in the industrial process. First, tests were carried out in laboratory conditions to determine the highest wettability and the lubricant remaining inside the tool cavity. These tests determined the lubrication system parameter settings which ensured that the greatest amount of lubricant remains in the cold die cavity without the forging process. Then, to verify the obtained results, tests were carried out in the industrial process of hot die forging of valve forgings, for short production runs of up to 500 forgings. The results were compared with the measurement of changes in the geometry of tools and forgings based on 3D scanning and surface topography analysis with the use of SEM. For best results (the variant of the setting of the dose and the time of exposure to lubricant), the forging process was carried out with the use of a new tool, up to the maximum service life.
Maternal Autogenous Inactivated Virus Vaccination Boosts the Piglet Humoral and Cell-Mediated Immunity to PRRSV via Transfer of Neutralizing Antibodies and Interferon-Gamma Producing B Cells
Authors: Kick Andrew R. , Wolfe Zoe C. , Amaral Amanda F. , Cortes Lizette M. , Almond Glen W. , Crisci Elisa , Gauger Phillip C. , Pittman Jeremy , Käser Tobias
Published: December 2020

Maternal-derived immunity is a critical component for survival and success of offspring in pigs to protect from circulating pathogens like Type 2 Porcine Reproductive and Respiratory Syndrome Virus (PRRSV-2). The purpose of this study was to investigate the transfer of anti-PRRSV immunity to piglets from gilts that received modified-live virus (MLV) alone (TRT 0), or in combination with one of two autogenous inactivated vaccines (AIVs, TRT 1+2). Piglets from these gilts were challenged with the autogenous PRRSV-2 strain at two weeks of age and their adaptive immune response (IR) was evaluated until 4 weeks post inoculation (wpi). The systemic humoral and cellular IR was analyzed in the pre-farrow gilts, and in piglets, pre-inoculation, and at 2- and 4-wpi. Both AIVs partially protected the piglets with reduced lung pathology and increased weight gain; TRT 1 also lowered piglet viremia best explained by the AIV-induced production of neutralizing antibodies in gilts and their transfer to the piglets. In piglets, pre-inoculation, the main systemic IFN-γ producers were CD21α+ B cells. From 0 to 4 wpi, the role of these B cells declined and CD4 T cells became the primary systemic IFN-γ producers. In lungs, CD8 T cells were the primary and CD4 T cells the secondary IFN-γ producers including a novel subset of porcine CD8α-CCR7- CD4 T cells, potentially terminally differentiated CD4 TEMRA cells. In summary, this study demonstrates that maternal AIV vaccination can improve protection of pre-weaning piglets against PRRSV-2; it shows the importance of transferring neutralizing antibodies to piglets; and it introduces two novel immune cell subsets in pigs – IFN-γ producing CD21α+ B cells and CD8α-CCR7- CD4 T cells.
Faktor resiko mastitis subklinis pada Kambing Peranakan Etawah di Kecamatan Kokap, Kulonprogo, Yogyakarta
Authors: Andityas Morsid , Artdita Clara Ajeng , Prihanani Nur Ika
Published: December 2020

Tujuan: Mastitis merupakan suatu peradangan yang terjadi pada glandula intramamari sebagai respon dari mekanisme pertahanan tubuh. Kejadian dan tingkat infeksi mastitis sangat dipengaruhi oleh berbagai macam faktor penyebab. Penelitian ini bertujuan untuk mengidentifikasi faktor-faktor resiko yang berhubungan dengan kejadian mastitis subklinis pada kambing peranakan etawah (PE) di Kecamatan Kokap, Kulonprogo, Yogyakarta.

Metode:Jenis metode yang digunakan pada penelitian ini adalah metode survei. Teknik sampling yang digunakan dalam penelitian ini adalah purposive sampling dengan jumlah 200 sampel susu segar dari kambing PE. Pengumpulan data dilakukan dengan metode wawancara (kuesioner), pengamatan langsung dan pengujian status mastitis dengan menggunakan reagen California Mastitis Test (CMT). Data penelitan ini dianalisis secara diskriptif dan analisis bivariat chi square (X2), Odds Ratio (OR), serta Relative risk (RR).

Hasil: Hasilpenelitian menunjukan bahwa faktor resiko yang berperan terhadap kejadian mastitis subklinis di Kecamatan Kokap adalah variabel umur sapih <2 bulan (X2=22,99; OR=21,13 dan RR=13,2) dan jarak pembuangan limbah <15 m dari kandang (X2=3,98; OR=6,52 dan RR=5,44).

Kesimpulan: Variabel faktor resiko umur sapih <2 bulan dan jarak pembuangan limbah <15 m dari kandang memiliki asosiasi kuat dengan infeksi mastitis subklinis di Kecamatan Kokap, Kulonprogo, Yogyakarta.
Pengaruh pemberian limbah sereh wangi (Cymbopogon nardus) fermentasi sebagai substitusi pakan basal terhadap kualitas semen domba ekor tipis
Authors: Mariana Elmy , Riski Nanda , Novita Cut Intan
Published: December 2020

Tujuan: Penelitian ini bertujuan untuk mengetahui pengaruh penggunaan limbah sereh wangi fermentasi sebagai substitusi pakan basal selama 14 hari terhadap kualitas semen domba ekor tipis.

Metode: Sebanyak 4 ekor domba ekor tipis jantan berumur antara 18-24 bulan dengan bobot badan 25,4±1,01 kg digunakan dalam penelitian ini. Penelitian menggunakan rancangan bujur sangkar latin (RBSL) yang terdiri dari 4 perlakuan dan 4 ulangan. Perlakuan P0 = Kontrol (tanpa substitusi limbah sereh wangi fermentasi), P1 = substitusi limbah sereh wangi fermentasi 10%, P2 = substitusi limbah sereh wangi fermentasi 20% dan P3 = substitusi limbah sereh wangi fermentasi 30%. Parameter yang diamati adalah kualitas makroskopis semen yang terdiri atas volume, warna, bau, pH dan konsistensi spermatozoa serta kualitas mikroskopis semen yang terdiri atas konsentrasi, gerakan massa dan motilitas spermatozoa.

Hasil: Hasil penelitian menunjukkan bahwa substitusi limbah sereh wangi fermentasi dengan konsentrasi yang berbeda tidak berpengaruh nyata terhadap kualitas semen. Volume, warna, bau, pH, konsistensi, konsentrasi, gerakan massa dan motilitas spermatozoa yang dihasilkan domba ekor tipis yang diberi limbah sereh wangi fermentasi sebagai substitusi pakan basal di kategorikan baik.
Kesimpulan: Kesimpulan penelitian ini penggunaan limbah sereh wangi fermentasi sebagai substitusi pakan basal selama 14 hari perlakuan tidak menyebabkan penurunan kualitas semen yang dihasilkan domba ekor tipis.
INFLUENCE OF SEASONAL FACTORS ON MORBIDITY OF teachers of GENERAL EDUCATION INSTITUTIONS IN THE OMSK REGION
Authors:   Omsk State Pedagogical University, Omsk, Russia, Zakorkina N.A.
Published: December 2020

The unfavorable trend of loss of health of teachers is determined by the growth of neglected forms of diseases and the influence of seasonal factors. Purpose. To study the influence of seasonal factors on the dynamics of primary morbidity of teachers of general educational institutions. Methods. The study of the incidence was carried out on the data of the appeal of teachers for medical care and data of medical examinations. The seasonal oscillation index was used to determine seasonal factors. Results. The incidence of teachers living in Omsk had a clear tendency to worsen in the following nosological forms: anemia, diabetes, obesity, peripheral nervous system diseases (neuritis, neuralgia, etc.), eye disease (myopia), diseases characterized by high blood pressure, coronary heart disease from 1.3 to 3.6 times (p<0.05), most of these forms are detected during medical examinations. In the structure of primary morbidity, the first three rank places were occupied by diseases of the respiratory, circulatory, endocrine system and metabolism. The total share of the first three groups of the above nosologies in the formation of pathologies was about 65%, and there was an increase in the average duration of temporary incapacity from 3 to 15 days. In addition, the effect of seasonal factors on the level of primary morbidity in diseases characterized by high blood pressure, diabetes, anaemia, which is associated with the cyclicality of the educational process and the date of medical examinations. Conclusions. 1. The deterioration of the health of teachers is due to an increase in primary morbidity, aggravated forms of diseases, including coronary heart disease, diabetes, anaemia, obesity, as well as an increase in the duration of days of temporary incapacity in these nosological forms. 2. Seasonal risk factors associated with the cyclicality of the learning process have been identified. Scope of application. The data can be used in the development and implementation of regional targeted prevention programs. Keywords: morbidity;nosological forms; teachers; seasonality; disability.
CONTRIBUTION OF CHANGES IN AGE-RELATED MORTALITY INTO DYNAMICS IN LIFE EXPECTANCY IN RURAL RUSSIA
Authors:   Institute of Agrarian Problems of the Russian Academy of Sciences, Saratov, Russia, Bylina S.G.
Published: December 2020

In recent decades, the State has undertaken serious efforts to stabilize demographic situation, reduce mortality and create enabling conditions for a sustainable increase in life expectancy. These measures are especially relevant for the rural population, as its demographic indicators are always lower than that of the urban population. Decomposition of the dynamics in life expectancy can serve as a means to facilitate solution of this problem. The purpose of the study is to analyze contribution of changes in mortality in different age groups into dynamics in life expectancy in the Russian rural population in 2017-2018. Material and methods: quantitative analysis, decomposition method using the UN methodology (United Nations, 1985). Results. The study found out that in 2017-2018 life expectancy among rural men grew more rapidly compared to rural women due to reduced infant mortality, as well as reduced mortality in ages 20-34 and 55-59. The decreased growth rate of life expectancy in the rural population in 2018 is accounted for by the increased dynamics in mortality among rural women at young ages (25–29) and among both men and women aged 40–54 and 65–69, respectively. The study also identified a greater negative contribution of mortality rates among rural women compared to rural men in life expectancy of the rural population. When implementing state policy measures to increase life expectancy and reduce mortality in the rural population a special attention should be focused on negative dynamics in the contribution of mortality in working ages over 40 among both rural men and rural women. Scope of application. The results of the study can be used both in adjusting state programs and developing possible forecast options for the demographic development of the Russian village. Key words: life expectancy; rural population; mortality; decomposition method.
ETIOPATHOGENETIC ASPECT OF EARLY REPRODUCTIVE LOSS WITHIN THE FRAMEWORK OF IMPROVING ORGANIZATION OF CARE DELIVERY TO WOMEN (ANALYTICAL REVIEW)
Authors:   Izhevsk State Medical Academy of the Ministry of Health of the Russian Federation, Izhevsk, Bushmeleva N.N. , Vakhrusheva Yu.N. ,   Izhevsk State Medical Academy of the Ministry of Health of the Russian Federation, Izhevsk
Published: December 2020

Significance. Reproductive loss is considered as a system indicator of mother and child service. The majority of spontaneous abortions occur in the first trimester. The frequency of this pathology, despite the development of medical and biological research and introduction of organizational measures, does not tend to decrease due to multifactorial nature of its etiology and pathogenesis. To reduce loss due to early spontaneous abortions, it is necessary to improve health care delivery to women through developing preventive measures with due regard to etiopathogenetic aspect of early reproductive loss. Purpose. To identify main etiopathogenetic and medico-social aspects of early spontaneous reproductive loss in order to improve organization of care delivery to women with this problem. Material and methods. Content analysis of 200 scientific publications by the Russian and foreign authors published in the main electronic databases ("CyberLeninka", "disserCat", "PubFacts", "PubMed", "Google Scholar", "eLibrary"). Results. The study analyzed major risk factors and causes of early spontaneous reproductive loss according to modern researchers. In parallel, the analysis of possible ways to improve organization of care delivery to women with spontaneous abortions at the present stage was carried out on the basis of the data obtained. Scope of application. An in-depth study of the etiology and pathogenesis of reproductive loss early in pregnancy contributes to the development of new well-founded organizational methods to reduce it. Avery described etiopathogenetic aspect should be reflected in the complex of preventive and rehabilitation measures for women with a history of early reproductive loss or at risk for miscarriage, as well as in the algorithms for managing pregnant women of these categories. The importance of a differentiated approach to patients with early spontaneous pregnancy loss and the need for their observation by doctors of different specialties are emphasized. Keywords: reproductive loss; early spontaneous pregnancy loss; miscarriage; spontaneous abortion; review; organization of care delivery for miscarriage.
MANAGEABLE FACTORS FOR IMPROVING QUALITY OF CARE FOR PRETERM NEWBORNS
Authors:   Far Eastern State Medical University, Khabarovsk, Plotonenko Z.A. , Senkevich O.A. ,   Far Eastern State Medical University, Khabarovsk, Vladimirova N.Yu. ,   Institute for Advanced Training of Health Care Specialists, Khabarovsk, Stupak V.S. ,   Federal Research Institute for Health Organization and Informatics of Ministry of Public Health of Russian Federation, Moscow, Sokolovskaya T.A. ,   Federal Research Institute for Health Organization and Informatics of Ministry of Public Health of Russian Federation, Moscow, Ovchinnikova O.V. ,   Far Eastern State Medical University, Khabarovsk
Published: December 2020

Significance. The need for resources in the health care system is constantly increasing. Identification of manageable factors to improve quality of care delivery to extremely (very) preterm newborns will make it possible to improve care delivery. Regular monitoring of the preterm birth indicator with an assessment of its outcomes and identification of manageable factors is extremely important and relevant in terms of its systematic nature for the region, country and the world as a whole. The purpose of this study is to identify manageable factors to improve quality of care provided to babies with very low weight at birth born before 32 weeks of gestation. Material and methods. A three-stage study on features of care delivery to newborns born before 32 weeks of gestation (stage 1 - 2012, stage 2 - 2015 and stage 3 - 2019) was conducted using the typical sampling method. Results. The study has identified the following manageable risk factors: peculiar adaptation and physical development of preterm babies (born before 32 weeks of gestation) due to various causes of preterm delivery. The study has also confirmed that the main causes of preterm birth before 32 weeks of gestation include hypoxia and infection, with hypoxia prevailing, which directly affects the physical development and adaptation of preterm newborns. There is a reliable relationship between the earliest delivery, as well as pathological nature of early adaptation of newborns, determined by the Apgar scale, and the most unfavorable outcomes in children born to women with infection. Conclusion. The study has determined the structure of causes of preterm delivery and characteristics of early adaptation of newborns, which can serve basis for preventing pathological conditions and predicting status of very preterm newborns.Implementation of organizational activities aimed at early detection and prevention of manageable risk factors with their subsequent monitoring will make it possible to strengthen positive dynamics in the rate of decline in negative demographic indicators. Scope of application. The results of the study can be used by specialists in health care organization, heads of medical organizations, specialists in gynecology and obstetrics and neonatology to improve quality of care delivery to extremely (very) preterm newborns. Keywords: manageable factors; morbidity indicators; mortality indicators; preterm newborns; causes of premature labor
ASSESSMENT OF NURSES ' READINESS TO INTRODUCTION OF DIGITAL TECHNOLOGIES AND VIDEO MONITORING SYSTEMS INTO CARE DELIVERY TO SERIOUSLY ILL (LOW-MOBILITY) PATIENTS
Authors:   I.M. Sechenov First Moscow State Medical University, Moscow, Kasimovskaya N.A. , Lebedev G.S. ,   I.M. Sechenov First Moscow State Medical University, Moscow, Poleshchuk I.A. ,   I.M. Sechenov First Moscow State Medical University, Moscow
Published: December 2020

Significance. The professional activity of nurses in multi-specialty hospitals includes a wide range of responsibilities with a high shift load, which can result in lower quality of care delivery to seriously ill (low-mobility) patients. At the same time, digital technologies are yet to be widely used in the professional activities of inpatient nurses, which serves basis for improving care delivery to seriously ill (low-mobility) patients through digital technologies and video monitoring systems. The purpose of the study: to assess readiness of nurses to the introduction of digital technologies and video monitoring systems in care delivery to seriously ill (low-mobility) patients. Material and methods: a study on readiness of nursing staff to the introduction of digital technologies and video monitoring systems in care delivery to seriously ill (low-mobility) patients was implemented (n=565). The analysis was carried out on the basis of descriptive statistics methods. The significance level is set equal to p<0.05. Results. The study shows that almost every fifth nurse 19.0% ±1.65% (CI 15.7% - 22.30%) is ready to carry out professional activities for seriously ill (low-mobility) patients under the control of a video monitoring system in order to improve quality of care delivery; almost every fifth nurse 19.9%±1.68% (CI 16.54% -23.26%) considers it possible to evaluate quality of care delivery to seriously ill (low-mobility) patients using digital technologies (surveillance systems, video cameras. Conclusions. Nurses of medical organizations (hospitals) are not always ready for the use of digital technologies and introduction of the round-the-clock video monitoring system, however they show readiness if quality of care to patients improves. Keywords: digital technologies; modern methods to monitor work of nurses; nursing; professional activities of nurses.
A Weighting Function-Based Method for Resistivity Inversion in Subsurface Investigations
Authors: Nie Lichao , Ma Zhao , Liu Bin , Xu Zhenhao , Zhou Wei , Wang Chengkun , Shao Junyang , Yin Xin
Published: December 2020

There is a high demand for high detection accuracy and resolution with respect to anomalous bodies due to the increased development of underground spaces. This study focused on the weighted inversion of observed data from individual array type electrical resistivity tomography (ERT), and developed an improved method of applying a data weighing function to the geoelectrical inversion procedure. In this method, the weighting factor as an observed data weighting term was introduced into the objective function. For individual arrays, the sensitivity decreases with increasing electrode interval. Therefore, the Jacobian matrices were computed for the observed data of individual arrays to determine the value of the weighting factor, and the weighting factor was calculated automatically during inversion. In this work, 2D combined inversion of ERT data from four-electrode Alfa-type arrays is examined. The effectiveness of the weighted inversion method was demonstrated using various synthetic and real data examples. The results indicated that the inversion method based on observed data weighted function could improve the contribution of observed data with depth information to the objective function. It has been proven that the combined weighted inversion method could be a feasible tool for improving the accuracies of positioning and resolution while imaging deep anomalous bodies in the subsurface.
Differential Target Antenna Coupling (DTAC) EM Surveying with Stationary Transmitter Loop and Moving In-Loop Receivers
Authors: Sternberg Ben K.
Published: December 2020

Following our previous studies of the Differential Target Antenna Coupling (DTAC) method with horizontal and vertical arrays for EM surveys, in this paper we study the application of the DTAC method to a different configuration, where a large, stationary transmitter loop is on the ground surface. We then run profile lines inside this loop. The DTAC method is effective in eliminating errors due to the large variations in the primary field along profile lines within the transmitting loop. Operational tests show that we obtain more diagnostic DTAC anomalies over buried targets than using just the Bx and By data. The DTAC method also produces smaller false-alarm targets due to background geology variations, compared with Bz measurements. The DTAC method can be used with either time- or frequency-domain data and the receiver can be moved on the ground or deployed from an airborne vehicle, such as a drone.
Ground Penetrating Radar for Water Content and Compaction Evaluation: A Laboratory Test on Construction Material
Authors: Roodposhti Hashem Ranjy , Hafizi Mohammad Kazem , Kermani Mohammad Reza Soleymani
Published: December 2020

With the aid of ground penetrating radar (GPR), it is possible to evaluate physical properties of a constructed base layer in engineered structures (pavement, land consolidation projects, etc.) non-destructively, quickly, and accurately. High spatial variations of subsurface water content and deficient compaction can lead to unexpected damage and structural instability. In this research, we established a relationship between the dielectric constant, water content, and compaction, whereby, an interactive relationship between these parameters is presented. To achieve this, large-scale laboratory experiments were carried out on construction materials to simulate field conditions. According to USCS, the tested soil type was GW-GM (type E base layer according to Iran's highway specifications code). Furthermore, water content and compaction were changed between 4% -12.9% and 84.7% -94.9%, respectively. The travel-times in each test, including three profiles with more than 210 traces, are measured automatically. Additionally, the calculated dielectric constants were compared with the Topp and Roth equations. R-square and RMS error of the final interactive equation between dielectric constant and water content-compaction were 0.95 and 0.41, respectively. Moreover, the sensitivity analysis of the proposed interactive equation shows that changes in water content of soil have greater impact on dielectric constant than soil compaction changes. The data also indicate the importance of considering the compaction changes of soil to reduce the error in dielectric constant estimation.
Using an Azimuth Electromagnetic Wave Imaging Method to Detect and Characterize Coal-seam Interfaces and Low-resistivity Anomalies
Authors: Chen Gang , Fan Yiren , Li Quanxi
Published: December 2020

It has been found that the traditionally used electromagnetic wave instruments have limitations in detection depths, as well as a lack of directionality. Therefore, those types of instruments cannot meet the needs of geo-steering applications. However, azimuth electromagnetic wave instruments have shown the ability to quickly acquire effective geo-steering information using a tilt coil design method, which can potentially provide accurate guidance for decision-making in drilling direction adjustments. In this study, a design method for an azimuth electromagnetic wave detection instrument for underground coal mining was proposed. The relationships between the structural parameters of the instrument and installation angles of the coils and the response signals were obtained in this study using simulations. Then, by choosing reasonable instrument spacings, coil installation angles, and transmitting frequencies, the detection performances of the instrument were successfully improved. Also, the basic parameter selections of the proposed logging-while-drilling azimuth electromagnetic wave logging instrument were determined to be suitable for underground coal-mining purposes. It was also found that the symmetric compensation of the instrument was sensitive to the interface responses, and the anti-symmetric compensation was sensitive to the anisotropic responses. In addition, a method of detecting the interface positions and azimuth of coal-seam interfaces using azimuth electromagnetic waves, as well as the potential for the application of the instrument for the detection of low-resistivity anomalies in coal goafs, were effectively demonstrated. The results of this study provided theoretical references for future coal-seam boundary detections and explorations, and also added insight into the development processes of coal-seam bedding.
Bayesian Time-lapse Difference Inversion Based on the exact Zoeppritz Equations with Blockiness Constraint
Authors: Zhou Lin , Liao Jianping , Li Jingye , Chen Xiaohong , Yang Tianchun , Hursthouse Andrew
Published: December 2020

Accurately inverting changes in the reservoir elastic parameters that are caused by oil and gas exploitation is of great importance in accurately describing reservoir dynamics and enhancing recovery. Previously numerous time-lapse seismic inversion methods based on the approximate formulas of exact Zoeppritz equations or wave equations have been used to estimate these changes. However the low accuracy of calculations using approximate formulas and the significant calculation effort for the wave equations seriously limits the field application of these methods. However, these limitations can be overcome by using exact Zoeppritz equations. Therefore, we study the time-lapse seismic difference inversion method using the exact Zoeppritz equations. Firstly, the forward equation of time-lapse seismic difference data is derived based on the exact Zoeppritz equations. Secondly, the objective function based on Bayesian inversion theory is constructed using this equation, with the changes in elastic parameters assumed to obey a Gaussian distribution. In order to capture the sharp time-lapse changes of elastic parameters and further enhance the resolution of the inversion results, the blockiness constraint, which follows the differentiable Laplace distribution, is added to the prior Gaussian background model. All examples of its application show that the proposed method can obtain stable and reasonable P- and S-wave velocities and density changes from the difference data. The accuracy of estimation is higher than for existing methods, which verifies the effectiveness and feasibility of the new method. It can provide high-quality seismic inversion results for dynamic detailed reservoir description and well location during development.
Imaging the Geology Ahead of a Tunnel Using Seismics and Adaptive Polarization Analysis
Authors: Chen Lei , Fu Chao , Xu Xinji , Nie Lichao
Published: December 2020

The seismic method is one of the main geophysical methods that are widely used to image the geology ahead of tunnels during tunnel construction. However, owing to the complex environment and limited observation aperture in a tunnel, symmetric false results (that appear in imaging results but not in the actual environment) frequently occur in imaging results. In a symmetric false reflection, false and true reflection points are axisymmetric around the tunnel axis. Such false results frequently cause errors in the interpretation of the geological conditions ahead of a tunnel face. To overcome this problem, a seismic method that uses adaptive polarization analysis was adopted to better image geological conditions. Based on an adaptive time window, the polarization characteristics of seismic signals were analyzed to calculate the main polarization direction. The symmetric false results in imaging results were suppressed by adopting a weighting coefficient based on the angle between the main polarization direction and ray direction. Numerical simulations revealed the superiority of the method when applied to synthetic data processing. Moreover, the method was applied to a diversion tunnel. The method successfully identified the fracture zones ahead of the tunnel face, thus significantly enhancing the safety of tunnel construction.
Ü-Net: Deep-Learning Schemes for Ground Penetrating Radar Data Inversion
Authors: Xie Longhao , Zhao Qing , Ma Chunguang , Liao Binbin , Huo Jianjian
Published: December 2020

Electromagnetic (EM) inversion is a quantitative imaging technique that can describe the dielectric constant distribution of a target based on the EM signals scattered from it. In this paper, a novel deep neural network (DNN) based methodology for ground penetrating radar (GPR) data inversion, known as the Ü-net is introduced. The proposed Ü-net consists of three parts: a data compression unit, U-net, and an output unit. The novel inversion approach, based on supervised learning, uses a neural network to generate the dielectric constant distribution from GPR data. The GPR data can be compressed and reshaped the size using data compression unit. The U-net maps the object features to the dielectric constant distribution. The output unit meshes the dielectric constant distribution more finely. A novel feature of the proposed methodology is the application of instance normalization (IN) to the DNN EM inversion method and a comparison of its performance to batch normalization (BN). The validity of this technique is confirmed by numerical simulations. The Mean-Square Error of the test data sets is 0.087. These simulations prove that the instance normalization is suitable for GPR data inversion. The proposed approach is promising for achieving quality dielectric constant images in real-time.
Study of EMR and AE during Coal Fracture under Quasi-static Uniaxial Compression Load
Authors: Li Chengwu , Wang Qifei , Ai Dihao , Dong Lihui , Wang Feiyin
Published: December 2020

A quasi-static uniaxial compression experiment was designed to simulate creep damage in coal. During the experiment, electromagnetic radiation (EMR) and acoustic emission (AE) signals were synchronously acquired. The energy of EMR and AE signals were subsequently calculated after the background noise from the equipment and the environment were filtered out. We then analyzed the change in signal energy associated with the sample strength, loading time and other factors. The results showed that as the loading time increases, the frequency of the periodic signal in the EMR energy also increases. In addition, the dominant AE signal energy release occurs only in the final stage of sample failure. However, intermittent AE pulse clusters were recorded during the entire loading cycle. The analysis of data provided a strong correlation between the change in the AE signal energy and the expansion of micro-cracks in the materials, which is manifested as an irreversible deformation of the material at the macroscopic scale.
Characterization and Delineation of Gypsum Karst Geohazards Using 2D Electrical Resistivity Tomography in Culberson County, Texas, USA
Authors: Majzoub Adam F. , Stafford Kevin W. , Brown Wesley A. , Ehrhart Jon T.
Published: December 2020

The Delaware Basin of W Texas and SE New Mexico is the western subdivision of the Permian Basin and a northern extension of the Chihuahuan Desert. The major evaporite unit within the Delaware Basin is the Castile Formation, which consists of gypsum/anhydrite and is highly susceptible to dissolution and karstification. Manifestations of karst within the Castile outcrop are abundant and include sinkholes, subsidence features and caves, both epigene and hypogene in origin.

Land reconnaissance surveys conducted during 2015 and 2016 documented abundant karst landforms near major thoroughfares in Culberson County, Texas. Two dimensional (2D) electrical resistivity surveys were conducted at four sites to characterize and delineate karst related hazards, both laterally and vertically, associated with the road. The electrical resistivity data were collected with a multi-electrode earth resistivity meter using a dipole-dipole array configuration. The resistivity data were then processed using EarthImager2D to produce inverted profile sections of each site. Two-dimensional electrical resistivity tomography was shown to be an effective non-invasive method in detecting solution conduits, soil filled voids, and fractured bedrock in the shallow subsurface in addition to those directly observed on the surface.
Elastic Parameters from Compressional and Shear Wave Tomographic Survey: A Case Study from Kuala Lumpur, Malaysia
Authors: von Ketelhodt Julius K. , Fechner Thomas , Manzi Musa S. D. , Durrheim Raymond J.
Published: December 2020

An integrated P- and S-wave cross-borehole tomographic survey was performed in the city center of Kuala Lumpur, Malaysia, with the aim of exploring a karstic limestone area near an area that previously encountered cavities. Horizontally polarized shear waves were generated with two opposing, perpendicular strike directions and recorded with a multi-level, three-component receiver array. This allowed a high quality picking of the traveltimes, whereby the wave train reverses at the time of the S-wave arrival. In addition, high quality sparker generated P-waves were recorded. The P- and S-wave traveltimes were used to invert for two co-located tomograms. These tomograms enabled a better interpretation capability than a P- or S-wave tomogram on its own. The tomograms enabled the calculation of the elastic parameters, i.e., P- to S-wave velocity (Vp/Vs) ratio, Poisson's ratio, bulk modulus, Young's modulus and the shear modulus, on a 2D surface between the boreholes. This further aided the interpretation, as areas with limited traveltime accuracy and thus, an increase in tomographic error, could be easily identified, and the extent of a large cavity could be estimated. The interpretation of the tomograms was constrained by two additional boreholes, which provided more confidence on the delineation and location of cavities at depths. The survey shows the benefit of co-locating P- and S-wave tomography surveys.
The Determination of the Burial Depth of Coal Measure Strata Using Electromagnetic Data
Authors: Xue Guo-qiang , Chen Kang , Chen Wei-ying , Tian Zhongbin
Published: December 2020

The water-rich zones in the coal fields of Northern China have seriously threatened the safe production of coal mines. It is necessary to accurately locate the deep seated and complex water bodies which are usually located in Ordovician limestone. Due to the relatively high cost of seismic exploration, the development effective electromagnetic detection methods and corresponding data processing techniques for the detection of these water-rich areas becomes a topic for the EM geophysicist. In this study, a method of rapidly estimating the burial depth and undulating morphology of coal bed foundations by employing frequency domain electromagnetic sounding data was proposed. The method uses the overshoot/undershoot phenomenon of the apparent resistivity for the frequency domain electromagnetic measurement to quantitatively determine the burial depth of the northern China coal structure bases. First, the featured frequency points were confirmed, where the overshoot and undershoot effects appeared in the electromagnetic sounding curves beside the borehole drilling sites. Then, the correlation coefficient between the confirmed frequency points and the burial depth of coal seam bed was obtained according to the drilling data. Finally, the burial depth of the coal seam beds in the entire survey area was evaluated based on the correlation coefficient and electromagnetic data. This method was applied in the northern areas of Taiyuan City in Shanxi Province, and achieved good results.

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Numerical Analysis of Land-Based Inline-Source Configuration for the Controlled-Source Electromagnetic Method
Authors: Li Hai , Xue Guo-qiang , Di Qing-yun
Published: December 2020

The geometry of source and receiver is one of the most crucial factors for the success of a controlled-source electromagnetic (CSEM) investigation. The inline electric-source configuration, widely used in the marine CSEM method, is not commonly employed for land CSEM surveys. To examine the feasibility of the inline electric-source time domain electromagnetic method (TEM), we first analyzed the optimal observing area for the land-based electric-dipole source by imaging the distribution of each component and the anomalies caused by a resistive or conductive target layer. Then, we conducted an error-space analysis to evaluate the sensitivity of each inline component based on the result of the optimal observation area. Finally, we collected field data from a typical inline dipole-dipole configuration and inverted the data with an algorithm based on Occam's principle.

[Figure: see text]
The Effects of 3D Electrical Anisotropy on Magnetotelluric Responses: Synthetic Case Studies
Authors: Kong Wenxin , Lin Changhong , Tan Handong , Peng Miao , Tong Tuo , Wang Mao
Published: December 2020

Using the staggered-grid finite difference method, a numerical modeling algorithm for a 3D arbitrary anisotropic Earth is implemented based on magnetotelluric (MT) theory. After the validation of this algorithm and comparison with predecessors, it was applied to several qualitative and quantitative analyses containing electrical anisotropy and a simple 3D prism model. It was found that anisotropic parameters for ρ1 , ρ2 , and ρ3 play almost the same role in affecting 3D MT responses as in 1D and 2D without considering three Euler's angles αS, αD, and αL. Significant differences appear between the off-diagonal components of the apparent resistivity tensor and also between the diagonal components in their values and distributing features under the influence of 3D anisotropy, which in turn help to identify whether the MT data are generated from 3D anisotropic earth. Considering the deflecting effects arising from the inconsistency between the anisotropy axes and the measuring axes, some strategies are also provided to estimate the deflecting angles associated with anisotropy strike αS or dip αD, which may be used as initial values for the 3D anisotropy inversion.

[Figure: see text]
Three-dimensional Land FD-CSEM Regularized Inversion Based on Edge Finite-element Method
Authors: Liu Jianxin , Liu Pengmao , Tong Xiaozhong
Published: December 2020

There is a desire to obtain rapid and stable inversion results and clearly reconstruct subsurface resistivity structure in frequency domain (FD) electromagnetics. Three-dimensional modeling of land FD controlled-source electromagnetic (CSEM) data is vital to improve the understanding of electromagnetic responses collected in increasingly complex geologic settings. Three-dimensional inversion of land FD-CSEM data is a mathematically non-unique problem with instability, due to the noise contained in the data and its inherent incompleteness. The main difference between our method and those from previous work is that the edge finite-element approach is applied to solve the three-dimensional FD-CSEM generated by a horizontal electric dipole source. Firstly, we formulate the edge finite-element equation through the Galerkin method, based on the Helmholtz equation of the electric fields. Secondly, in order to check the validity of the modeling code, we compare the numerical results with the analytical solutions for a homogeneous half-space model. For further tests, we calculate the electromagnetic responses for another two models with more practical structures. Finally, the three-dimensional inversion is carried out based on a regularization method with smoothness-constraints to obtain stable solutions.
3-D Butterworth Filtering for 3-D High-density Onshore Seismic Field Data
Authors: Liao Jianping , Liu Hexiu , Li Weibo , Guo Zhenwei , Wang Lixin , Wang Huazhong , Peng Suping , Hursthouse Andrew
Published: December 2020

Three-dimensional seismic survey is widely applied, but 3-D filtering technology has yet to be fully utilized for the analysis of seismic field data. The common approach is to first filter inline and then crossline. However, an effective 3-D filtering method is expected to eliminate coherent noise, such as the ground roll. We propose a 3-D Butterworth filtering method in the time-space domain. Firstly, a Butterworth-type filter in the frequency-wavenumber-domain is designed to suppress the linear noise with a specific apparent velocity. Secondly, transforming this filter to the time and space domain yields 3-D partial differential equations (PDEs), which are applied to suppress the linear noise. Factorizing the finite-difference equations in a different direction other than decreasing the 3-D PDEs to 2-D PDEs produces a highly accurate and efficient algorithm. Designing the 3-D Butterworth filter, selecting the filtering parameters, and showing its application to synthetic data and a 3-D high-density onshore seismic field data from a region in western China are discussed in detail. Numerical experiments with 3-D high-density onshore seismic field data demonstrate that it is more effective than the 3-D frequency-wavenumber-wavenumber (FKK) filtering method.