bluuebunny/crossref_metadata_2025 huggingface dataset:
Two keys to Pyongyang’s past and future – moral center and Korean War
Authors: Jung Mee Kyung
Published: April 2021

Pyongyang has been described as a center of evil that threatens the world with nuclear weapons. The city is perceived as both aggressive and controlled. This study explains those particularities of Pyongyang utilizing Wagner, Rudolf (2000) (“The moral center and the engine of change. A tale of two Chinese cities”. In: Peking Shanghai Shenzhen. Städte des 21. Jahrhunderts. Beijing Shanghai Shenzhen. Cities of the 21st Century. Vöckler, K and Luckow, D (eds.). Frankfurt: Campus Verlag, Edition Bauhaus, vol. 7, 452–459) theory of the Northeast Asian city as a moral center under the ongoing Korean War (although a ceasefire has been called, the war has not officially ended). This study starts by drawing similarities between Pyongyang and Hanyang, the capital of the Joseon Dynasty, which was established as a moral center according to the Rites of the Zhou Dynasty. I also look at the influence that the Korean War had on Pyongyang and find that Pyongyang was constructed to express the North Koreans socialist Juche ideology (self-reliance, subjecthood), while Hanyang expressed Confucian ideology. Pyongyang is more than just a moral center; it is “the Holy Land of Revolution” according to the “Administration Act of the Capital City Pyongyang”, where the war still takes place to defend the Juche Ideology and its supreme leader. The Korean War justifies the control in North Korea. The country utilizes the five-family control system inherited from the Joseon Dynasty. Its origin is legalism during the Warring States period (770−221 BC) in China. Control in Pyongyang has been strengthened because of the need for military operations in the unfinished Korean War, compared to Hanyang. Having relaxed political tensions in 2019, North Korea offers a vision for the future of Pyongyang as a “socialist fairyland” (seongyeong 仙境), which is related to Korea’s own Taoism (sinseon sasang 神仙思想). Developing Pyongyang with the Juche ideology from a Confucian tradition in the war, the city now reveals a unique means of cultural entanglement.
Marco Polo: From Hangzhou to Quanzhou
Authors: Haw Stephen G.
Published: April 2021

When Marco Polo left China, he passed through Hangzhou (Quinsai) and then travelled approximately southwestwards into what is today Fujian province, to the cities of Fuzhou and Quanzhou (Zaiton). There are still a number of disagreements regarding his route, however, which are discussed here. Consideration is also given to Marco’s use of “Facfur” to designate the last Emperor of the Song dynasty, and more generally to the issue of the use of Persian language in Yuan China. It is suggested that there is no clear evidence that Marco Polo learned Persian. An error regarding consumption of pepper in China during the thirteenth century is corrected. More evidence of the importation of very substantial quantities of pepper into China during the Song and Yuan periods is adduced. Identifications of all the places which Marco mentions in this section of his book are suggested, with the support of evidence.
Comparison between voltammetric detection methods for abalone-flavoring liquid
Authors: Lv Yan , Zhang Xu , Zhang Peng , Wang Huihui , Ma Qinyi , Tao Xueheng
Published: April 2021

This article attempts to determine the most accurate classification method for different abalone-flavoring liquids. Three common voltammetric detection methods, namely, linear sweep voltammetry (LSV), cyclic voltammetry (CV), and square-wave voltammetry (SWV), were considered. To compare their classification accuracies of abalone-flavoring liquids, three methods were separately adopted to classify five different abalone-flavoring liquids, using a four-electrode (Au, Pt, Pd, and W) sensor array. Then the data acquired by each method were subject to the principal component analysis (PCA): the first three principal components whose eigenvalues were greater than 1 were extracted from each set of data; the cumulative variance contribution rate and the principal component scores of each method were obtained. The PCA results show that the first three principal components obtained by the CV had the highest cumulative variance contribution rate (91.307%), indicating that the CV can more comprehensively characterize the information of abalone-flavoring liquid samples than the other two methods. According to the principal component scores, compared with those of LSV and SWV, the same kind of samples detected by the CV were highly clustered and the different kinds of samples detected by the CV were greatly dispersed. This indicates that the CV can effectively distinguish between the five abalone-flavoring liquids. Finally, the detection data were further verified through probabilistic neural network and a support vector machine algorithm optimized by genetic algorithm. The results further confirm that the CV is more accurate than the other two methods in the classification of abalone-flavoring liquids. Therefore, the CV was recommended for the classification of abalone-flavoring liquids.
Improved generalized periods estimates over curves on Riemannian surfaces with nonpositive curvature
Authors: Wyman Emmett L. , Xi Yakun
Published: April 2021

We show that, on compact Riemannian surfaces of nonpositive curvature, the generalized periods, i.e. the 𝜈-th order Fourier coefficients of eigenfunctions

e
λ

e_{\lambda}

over a closed smooth curve 𝛾 which satisfies a natural curvature condition, go to 0 at the rate of

O
⁢

(

(

log
⁡
λ

)

-

1
2

)

O((\log\lambda)^{-\frac{1}{2}})

in the high energy limit

λ
→
∞

\lambda\to\infty

if

0
<

|
ν
|

λ

<

1
-
δ

0<\frac{\lvert\nu\rvert}{\lambda}<1-\delta

for any fixed

0
<
δ
<
1

0<\delta<1

.
Our result implies, for instance, that the generalized periods over geodesic circles on any surfaces with nonpositive curvature would converge to zero at the rate of

O
⁢

(

(

log
⁡
λ

)

-

1
2

)

O((\log\lambda)^{-\frac{1}{2}})

.
An investigation of synchronization robustness considering randomness and asymmetries
Authors: Carvalho Phablo R. , Savi Marcelo A.
Published: April 2021

Synchronization phenomena are related to several natural systems defining patterns of interactions. This paper deals with a synchronization robustness investigation evaluating pattern formation on a network of pendulum-chart oscillators receiving energy from a base excitation. Random aspects are investigated establishing the sensitivity to parameter changes and initial conditions. System asymmetries are analysed allowing the investigation of different kinds of dynamical patterns. Results show that asynchronous regions can change due to random effects. The asynchronous region reduces with the dissipation increase and the chimera state can occur under parametric asymmetry. Energetic argues are employed to explain the pattern robustness with respect to randomness and asymmetries.
Conditional stability for an inverse coefficient problem of a weakly coupled time-fractional diffusion system with half order by Carleman estimate
Authors: Ren Caixuan , Huang Xinchi , Yamamoto Masahiro
Published: April 2021

Under a priori boundedness conditions of solutions and coefficients, we prove
a Hölder stability estimate for an inverse problem of
determining two spatially varying zeroth order non-diagonal elements of a coefficient matrix
in a one-dimensional fractional diffusion system of
half order in time.
The proof relies on the conversion of the fractional diffusion
system to a system of order 4
in the space variable and the Carleman estimate.
Detection of velocity and attenuation inclusions in the medical ultrasound tomography
Authors: Filatova Victoria , Pestov Leonid , Poddubskaya Alina
Published: April 2021

The paper is devoted to numerical research of the medical ultrasound tomography problem. This problem consists in finding small inclusions in the breast tissue by boundary measurements of the acoustic waves generated by sources located on the boundary. For medical diagnostic, it is important to recover the image of the acoustical medium and to determine the values of velocity, attenuation and density. In the paper, we describe a numerical experiment of visualization of several inclusions using the energy version of the reverse time migration (RTM). Certainly, the RTM image does not separate velocity and attenuation inclusions. However, kinematic and amplitude analysis gives a possibility to estimate values of the velocity and attenuation. As a result, we split the RTM image into two ones. Note that in this paper we consider the scalar value of sound velocity.
Prediction of encephalopathy in perinatal asphyxia score: reaching the unreached
Authors: Doreswamy Srinivasa Murthy , Ramakrishnegowda Amulya
Published: April 2021

Objectives

Neonates who develop moderate to severe encephalopathy following perinatal asphyxia will benefit from therapeutic hypothermia. Current National Institute of Child Health and Human Development (NICHD) criteria for identifying encephalopathic neonates needing therapeutic hypothermia has high specificity. This results in correctly identifying neonates who have already developed moderate to severe encephalopathy but miss out many potential beneficiaries who progress to develop moderate to severe encephalopathy later. The need is therefore not just to diagnose encephalopathy, but to predict development of encephalopathy and extend the therapeutic benefit for all eligible neonates. The primary objective of the study was to develop and validate the statistical model for prediction of moderate to severe encephalopathy following perinatal asphyxia and compare with current NICHD criteria.

Methods

The study was designed as prospective observational study. It was carried out in a single center Level 3 perinatal unit in India. Neonates>35 weeks of gestation and requiring resuscitation at birth were included. Levels of resuscitation and blood gas lactate were used to determine the pre-test probability, Thompson score between 3 and 5 h of life was used to determine post-test probability of developing encephalopathy. Primary outcome measure: Validation of Prediction of Encephalopathy in Perinatal Asphyxia (PEPA) score by Holdout method.

Results

A total of 55 babies were included in the study. The PEPA score was validated by Holdout method where the fitted receiver-operating characteristic (ROC) area for the training and test sample were comparable (p=0.758). The sensitivity and specificity of various PEPA scores for prediction of encephalopathy ranged between 74 and 100% in contrast to NICHD criteria which was 42%. PEPA score of 30 had a best combination of sensitivity and specificity of 95 and 89% respectively.

Conclusions

PEPA score has a higher sensitivity than NICHD criteria for prediction of Encephalopathy in asphyxiated neonates.
Surface enhanced Raman scattering analysis with filter-based enhancement substrates: A mini review
Authors: Xu Fugang , Xuan Mengren , Ben Zixiang , Shang Wenjuan , Ma Guangran
Published: April 2021

Surface enhanced Raman is a powerful analytical tool with high sensitivity and unique specificity and promising applications in various branches of analytical chemistry. Despite the fabrication of ingenious enhancement substrate used in laboratory research, the development of simple, flexible, and cost-effective substrate is also great important for promoting the application of SERS in practical analysis. Recently, paper and filter membrane as support to fabricate flexible SERS substrates received considerable attentions. Paper-based SERS substrate has been reviewed but no summary on filter-based SERS substrate is available. Compared with paper, filter membrane has unique advantage in robust mechanics, diverse component, and tunable pore size. These characteristics endow the filter-based substrates great advantages for practical SERS analysis including simple and low-cost substrate preparation, high efficiency in preconcentration, separation and detection procedure. Therefore, filter-based substrates have shown great promise in SERS analysis in environment monitoring, food safety with high sensitivity and efficiency. As more and more work has been emerged, it is necessary to summarize the state of such a research topic. Here, the research on filter involved SERS analysis in the past eight years is summarized. A short introduction was presented to understand the background, and then the brief history of filter-based substrate is introduced. After that, the preparation of filter-based substrate and the role of filter are summarized. Then, the application of filter involved SERS substrate in analysis is presented. Finally, the challenges and perspective on this topic is discussed.
Control-oriented quasi-one dimensional modeling method for scramjet
Authors: Xi Zhihua , Gao Yuan , Liu Minglei , Zhang Haibo
Published: April 2021

The scramjet model used in the control system needs to consider both accuracy and real-time requirements. In this paper, a quasi-one dimensional component level model method for scramjet is proposed. Under the premise of meeting the real-time requirement, this modeling method has higher calculation accuracy, and can obtain higher thrust performance without exceeding the limits. In order to improve the calculation accuracy of the scramjet model, the boundary layer correction and the interaction between shock wave and boundary layer are considered in the inlet and isolator modeling process by using reference temperature method. For the scramjet compression components, the inlet and isolator models are simplified based on shock train theory to improve real-time performance. Meanwhile, the combustor model and nozzle model are established and the combustor model is established with the combination of equal area and isothermal based on temperature limitation. Considering the boundary layer correction, the accuracy of the inlet and isolator model is improved by 8.79 and 7.9% respectively. Compared with the equal area combustion mode, the combined combustion mode can get higher thrust. In the C + + simulation environment, the average calculation time of each state point is about 25 ms which meets the real-time requirements.
A 2-D Zn(II) coordination polymer based on 4,5-imidazoledicarboxylate and bis(benzimidazole) ligands: synthesis, crystal structure and fluorescence properties
Authors: Xia Xinzhao , Xia Lixian , Zhang Geng , Jiang Yuxuan , Sun Fugang , Wu Huilu
Published: April 2021

In this work, a new type of zinc(II) coordination polymer {[Zn(HIDC)(BBM)0.5]·H2O}
n
(Zn-CP) was synthesized using 4,5-imidazoledicarboxylic acid (H3IDC) and 2,2-(1,4-butanediyl)bis-1,3-benzimidazole (BBM) under hydrothermal conditions. Its structure has been characterized by infrared spectroscopy, elemental analysis and single crystal X-ray diffraction analysis. The Zn(II) ion is linked by the HIDC2− ligand to form a zigzag chain by chelating and bridging, and then linked by BBM to form a layered network structure. Adjacent layers are further connected by hydrogen bond interaction to form a 3-D supramolecular framework. The solid-state fluorescence performance of Zn-CP shows that compared with free H3IDC ligand, its fluorescence intensity is significantly enhanced.
Unraveling the Mechanisms Underlying Irregularities in Inspiratory Rhythm Generation in a Mouse Model of Parkinson's Disease
Authors: Oliveira Luiz M. , Baertsch Nathan A. , Moreira Thiago S. , Ramirez Jan-Marino , Takakura Ana C.
Published: April 2021

Parkinson's disease (PD) is a neurodegenerative disorder anatomically characterized by a progressive loss of dopaminergic neurons in the substantia nigra compacta (SNpc). Much less known, yet clinically very important, are the detrimental effects on breathing associated with this disease. Consistent with the human pathophysiology, the 6-hydroxydopamine hydrochloride (6-OHDA) rodent model of PD shows reduced respiratory frequency (fR) and NK1r-immunoreactivity in the pre-Bötzinger complex (preBötC) and PHOX2B+neurons in the retrotrapezoid nucleus (RTN). To unravel mechanisms that underlie bradypnea in PD, we employed a transgenic approach to label or stimulate specific neuron populations in various respiratory-related brainstem regions. PD mice were characterized by a pronounced decreased number of putatively rhythmically active excitatory neurons in the preBötC and adjacent ventral respiratory column (VRC). Specifically, the number of Dbx1 and Vglut2neurons was reduced by 47.6% and 17.3%, respectively. By contrast, inhibitory Vgat+neurons in the VRC, as well as neurons in other respiratory-related brainstem regions, showed relatively minimal or no signs of neuronal loss. Consistent with these anatomic observations, optogenetic experiments identified deficits in respiratory function that were specific to manipulations of excitatory (Dbx1/Vglut2) neurons in the preBötC. We conclude that the decreased number of this critical population of respiratory neurons is an important contributor to the development of irregularities in inspiratory rhythm generation in this mouse model of PD.

SIGNIFICANCE STATEMENTWe found a decreased number of a specific population of medullary neurons which contributes to breathing abnormalities in a mouse model of Parkinson's disease (PD).
Begriff des Zahlungsinstruments und Haftungsverteilung beim CEO-Fraud
Authors: Zahrte Kai
Published: April 2021

Der BGH hat Ende 2020 grundsätzliche Feststellungen zur Haftung beim sog. CEO-Fraud und zum Begriff des Zahlungs(authentifizierungs)instruments getroffen. Gleichzeitig zeigt er auf, unter welchen Bedingungen Zahlungsdienstleister Kundenaufträge relativ rechtssicher auch per Fax annehmen können. Das Urteil dürfte deswegen Folgen für die Ausgestaltung von Kundenbedingungen im Zahlungsverkehr haben.
PhoneMe Poetry: Mapping Community in the Digital Age
Authors: Balyasnikova Natalia , James Kedrick
Published: April 2021

In this paper we explore how place-based poetry mediated online enabled community self-representation. Located in the urban core of a large cosmopolitan Canadian city, the PhoneMe project brought together academic researchers and community members into a collaborative educational creative space. Community members created poems about specific places within their neighbourhood, dialed a designated phone number, and recorded the poem by leaving a voice message. Upon receiving the message, the academic team geotagged it on an interactive map, uploaded the poem’s text, featured a Google Streetview image of the location, and shared the post via social media. As the result, a new vision for this distinctive physical space emerged and reached the wider audiences via engagement with the poetic digital media.
Increasing Volume-Targeted Ventilation Use in the NICU
Authors: Hatch L. Dupree , Sala Christa , Araya Wendy , Rivard Matthew , Bolton Joyce , Rivard Amanda , Morris Emily A. , McNeer Elizabeth , Guttentag Susan H. , Grubb Peter H. , Stark Ann R. , Markham Melinda H.
Published: April 2021

BACKGROUND:

In preterm infants who require mechanical ventilation (MV), volume-targeted ventilation (VTV) modes are associated with lower rates of bronchopulmonary dysplasia compared with pressure-limited ventilation. Bronchopulmonary dysplasia rates in our NICU were higher than desired, prompting quality improvement initiatives to improve MV by increasing the use of VTV.

METHODS:

We implemented and tested interventions over a 3-year period. Primary outcomes were the percentage of conventional MV hours when any-VTV mode was used and the percentage of conventional MV hours when an exclusively VTV mode was used. Exclusively VTV modes were modes in which all breaths were volume targeted. We evaluated outcomes during 3 project periods: baseline (May 2016–December 2016); epoch 1 (December 2016–October 2018), increasing the use of any-VTV mode; and epoch 2 (October 2018–November 2019), increasing the use of exclusively VTV modes.

RESULTS:

Use of any-VTV mode increased from 18 694 of 22 387 (83%) MV hours during baseline to 72 846 of 77 264 (94%) and 58 174 of 60 605 (96%) MV hours during epochs 1 and 2, respectively (P < .001). Use of exclusively VTV increased from 5967 of 22 387 (27%) during baseline to 47 364 of 77 264 (61%) and 46 091 of 60 605 (76%) of all conventional MV hours during epochs 1 and 2, respectively (P < .001). In statistical process control analyses, multiple interventions were associated with improvements in primary outcomes. Measured clinical outcomes were unchanged.

CONCLUSIONS:

Quality improvement interventions were associated with improved use of VTV but no change in measured clinical outcomes.
SARS-CoV-2 Infection Dynamics in Children and Household Contacts in a Slum in Rio de Janeiro
Authors: Lugon Pâmella , Fuller Trevon , Damasceno Luana , Calvet Guilherme , Resende Paola Cristina , Matos Aline Rocha , Machado Fumian Tulio , Malta Fábio Correia , Salgado Aline Dessimoni , Fernandes Fernanda Christina Morone , Abreu de Carvalho Liege Maria , Guaraldo Lusiele , Bastos Leonardo , Cruz Oswaldo Gonçalves , Whitworth James , Smith Chris , Nielsen-Saines Karin , Siqueira Marilda , Carvalho Marilia Sa , Brasil Patricia
Published: April 2021

OBJECTIVES

To investigate the dynamics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in a vulnerable population of children and their household contacts.

METHODS

SARS-CoV-2 reverse transcription polymerase chain reaction assays and coronavirus disease 2019 (COVID-19) immunoglobulin G serology tests were performed in children and their household contacts after enrollment during primary health care clinic visits. Participants were followed prospectively with subsequent specimens collected through household visits in Manguinhos, an impoverished urban slum (a favela) in Rio de Janeiro at 1, 2, and 4 weeks and quarterly post study enrollment.

RESULTS

Six hundred sixty-seven participants from 259 households were enrolled from May to September 2020. This included 323 children (0–13 years), 54 adolescents (14–19 years), and 290 adults. Forty-five (13.9%) children had positive test results for SARS-CoV-2 polymerase chain reaction. SARS-CoV-2 infection was most frequent in children aged <1 year (25%) and children aged 11 to 13 years (21%). No child had severe COVID-19 symptoms. Asymptomatic infection was more prevalent in children aged <14 years than in those aged ≥14 years (74.3% and 51.1%, respectively). All children (n = 45) diagnosed with SARS-CoV-2 infection had an adult contact with evidence of recent infection.

CONCLUSIONS

In our setting, children do not seem to be the source of SARS-CoV-2 infection and most frequently acquire the virus from adults. Our findings suggest that, in settings such as ours, schools and child care potentially may be reopened safely if adequate COVID-19 mitigation measures are in place and staff are appropriately immunized.
A literature review on the affective factors that influence data-driven decision-making
Authors: Sebestyén Edmond
Published: April 2021

Data-driven decision-making (DDDM) has been playing an increasing role in contemporary teaching, since it includes systematic collection, analysis, and application of data to improve students’ educational performance. However, little is known about the affective factors that influence this data-based practice. Thus, the purpose of this study was to systematically examine previous research on the affective factors that influence DDDM based on the following criteria: (1) the level of DDDM usage; (2) the emphasis of affective factors; and (3) the nature of the interventions and their effects on teachers. According to the findings, this literature review showed how little DDDM-related affective factors have been researched, even though the knowledge of DDDM can help expand its application in the educational field. For example, although the most widely used tool is the Data-Driven Decision-Making Efficacy and Anxiety Inventory (3D-MEA), which has shown promising results in terms of measuring the efficacy and development of data literacy, other affective components have yet to be tested, due to their novelty in the field. The implication of the findings is that obtaining more information about DDDM and its affective elements can help reduce teachers’ anxiety toward this approach and ultimately enhance the overall educational process.
INFLUENCE OF THERMOPHYSICAL AND PHYSICO-MECHANICAL PROPERTIES OF CATHODES ON DEFECTS FORMATION AND COMPOSITION OF TI1–XALXN COATINGS DURING CATHODIC ARC
Authors:   Perm National Research Polytechnic University, Kameneva Anna , Kameneva Natalya ,   Perm National Research Polytechnic University
Published: April 2021

The effect of the thermal state of the hard alloy and the Ti1−xAlxN coating during its cathodic arc evaporation on the physicmechanical and tribological properties of the coating has been studied. The dependence of the structure formation process of the Ti1−xAlxN coating on its temperature during deposition was obtained experimentally. A nanostructured Ti1–xAlxN coating is formed in the range 850–1015 K at a heating rate of 6 K / min. A decrease in the hardness of the HG30-Ti1−xAlxN composition at temperatures above 960 K was experimentally revealed. The decrease in the hardness of the HG30-Ti1−xAlxN composition under these temperature conditions is caused by a significant increase in the plasticity zone and grain size WC, as well as a decrease in the hot hardness of the HG30 alloy. Thus, it has been revealed that the optimum deposition temperature of the coating on HG30 should not exceed 850–900 K. The high voltage and duration of ion cleaning of the HG30 substrate are corrected to reduce its initial temperature before the deposition of the Ti1−xAlxN coating by the method of cathodic arc evaporation. By optimizing the thermal state of the HG30 substrate and the nanostructured Ti1−xAlxN coating during its deposition, it became possible to increase the physicmechanical properties and reduce the friction coefficient of the Ti1−xAlxN coating. Compared to foreign analogs, the obtained Ti1−xAlxN coating has a higher wear resistance (H / E = 0.1), plastic deformation resistance (H3 / E2 = 1.31 GPa) and elastic recovery (Wе = 76 %). Monitoring the thermal state of the substrate and the Ti1−xAlxN coating during its deposition makes it possible to control the process of its structure formation, as well as to prevent the gradient of the composition and properties of the formed coatings, and to increase the thermo-mechanical load on the tool and parts during cutting and operation. This technique can be used for other thin-film coating methods.
Loss classification and review of secondary flow models in gas turbine cascades
Authors:   JSC «UEC-Aviadvigatel», Piskunov Stanislav , Popov Denis ,   JSC «UEC-Aviadvigatel», Samoylenko Nikita ,   Perm National Research Polytechnic University
Published: April 2021

Much attention is paid to increasing the efficiency of turbofan engines by increasing the efficiency of the main modules. The aerodynamic efficiency of a turbine depends on the level of total pressure and kinetic energy losses, which are determined by the scale of secondary flows in the channels of the turbine cascades. There are many studies and articles on the topic of secondary flows, in which vortex structures are often given incorrect names. The problem lies in the absence of a unified model of secondary flows and mismatch in the names of the components of secondary flows in adaptation of model descriptions from English to Russian. The purpose of this review article is to consider the existing classifications of losses and the most famous models of secondary flows in turbine cascades, including the Wang model, the Goldstein and Spores model, the Sharma and Butler model, etc. The considered sources of information made it possible to single out the most complete classification of losses, compare with each other the components of secondary flows of various models, describe the mechanism of their occurrence and give the most complete nomenclature of secondary flows in turbine cascades.
NUMERICAL AND EXPERIMENTAL STUDY OF MULTILAYERED CYLINDRICAL BODIES WITH LOCAL BUNDLES
Authors:   Perm National Research Polytechnic University, Bulbovich Roman , Oznobishin Aleksey ,   PJSC “Research and Produc-tion Association “Iskra”, Rogozhikova Elena ,   PJSC “Research and Pro-duction Association “Iskra”,   Perm National Research Polytechnic University
Published: April 2021

A numerical and experimental study of the regularities of the influence of the most likely defects such as local bundles inside multilayer cylindrical large-sized housings on the deformation and strength characteristics of the housings near their end connection is carried out. A statistical analysis of discontinuities in the manufacture of holes for pin-pin connection at the front and rear junctions of the joint is carried out. To form a sample, the results of accompanying passports of more than 200 build-ings were processed. Based on the results of ultrasonic flaw detection, the areas of discontinuities at the front and rear junctions of the joint were determined, and as a result of statistical processing, diagrams of the distribution of discontinuities were con-structed. Physical models of cases in the form of multilayered cylindrical rings with the presence of probable defects in the structure such as local bundles are made and, further, to conduct ring tests according to the standard method to study the effect of local bundles on the deformation and strength characteristics of the ring. The relationship between the relative strength limit and the coefficient of discontinuity (delamination) of the composite structure of the ring is established using the obtained exper-imental data. A defect in the form of a bundle, on the one hand, leads to a decrease in the mechanical characteristics of the ma-terial, and on the other hand, leads to a concentration of stresses in the bundle zone. The total effect of stratification is ex-pressed in an increase in the corresponding stresses that characterize the state of the loaded structure, and, accordingly, a de-crease in its load-bearing capacity. A mathematical model is developed and numerical modeling is performed on its basis.
RESEARCH OF ADHESIVE AND HEAT-PROTECTIVE PROPERTIES OF RUBBERS BASED ON EPDM WITH ARAMID FILLER
Authors:   Perm National Research Polytechnic University, Shaydurova Galina , Oros Dmitriy ,   PJSC “Research and Production Association “Iskra”, Povarnitsyna Natalya ,   PJSC “Research and Production Association “Iskra”
Published: April 2021

Reinforced materials of the "fabric filler-vulcanized rubber" type may be successfully operated under the condition of the specified adhesive strength at the interface of the "substrate-polymer (rubber) "contact. The article presents theoretical infor-mation about ethylene propylene (EDM) and ethylene-propylene-diene (EPDM) synthetic rubbers, known internationally under the brand name EPDM-monomer, arimide fiber and laboratory research methods. The advantages of using EDM and EPDM in the manufacture of heat-protection coatings are; high heat resistance, low density, good compatibility with fillers (mineral and synthetic), compatibility with epoxy and phenol-formaldehyde resins, belong to coking materials. The article also provides the results of experiments and analysis of the data obtained, namely, the adhesive strength and thermal effect of rubbers based on EPDM with an arimide filler of a non-woven structure. The object of the research was modified heat-protective materials based on EPDM, and the subject of the research was selected rubber compounds based on EPDM and synthetic arimide fiber. To as-sess the physicochemical and thermophysical properties, a derivatographic analysis was performed, which includes TGA and DTA, two vulcanized rubber-woven samples from rubbers of grades 51-1615, 51-2110 together with arimide fiber. For the first time, results were obtained using ethylene-propylene-diene rubbers, including modification with a phenol-formaldehyde resin, which gives a higher erosion resistance when exposed to high-speed heat flow. Analysis of the results of experimental studies has shown that the use of arimide fiber can provide higher strength and thermophysical properties of heat-protective materials. In general, the results obtained may be of practical significance for the development of new-generation products.
Assessing the Impact of Uncertainty Parameters on Forcasting Production Parameters
Authors:   PermNIPIneft branch of LUKOIL-Engineering LLC in Perm, Nikita D. Nikita D. , Vishnyakov Aleksey Yu. ,   PermNIPIneft branch of LUKOIL-Engineering LLC in Perm, Putilov Ivan S. ,   PermNIPIneft branch of LUKOIL-Engineering LLC in Perm
Published: April 2021

At the stage of developing a geological and hydrodynamic reservoir model, uncertainties in input data may lead to errors in simulation results and subsequent inaccurate economic evaluations of oil or gas field potentials. In order to improve predictive reliability, a study was completed to assess how input data of a hydrodynamic model influence forecasts of main parameters of a production using the example of the Tournaisian site of the Soldatovskoye field. The study presents an approximate algorithm reducing uncertainties and improving the forecast reliability of the production parameters obtained using a geological and hydrodynamic reservoir model. The algorithm includes a substantiated selection of the initial sensitivity parameters, an evaluation of the impact of the initial parameters on the hydrodynamic reservoir model using the sensitivity analysis, as well as a selection of an optimal range of variations of the uncertainty parameters as a result of the multivariant hydrodynamic simulation adaptation, calculation and analysis of the multivariant hydrodynamic reservoir model forecast. The study aims to clarify the design process parameters of the development, assess the risks of non-confirmation of the hydrodynamic simulation forecasting, and make recommendations and proposals to study those uncertainty parameters, which influence most on certain predicted production parameters of an asset. As a result, a block diagram of the approach is presented in order to generalize and replicate it on potential and important oil and gas fields. The described approach of the model adaptation and calculations of the predicted options in conditions of uncertainty of the initial model parameters make it possible to obtain a more accurate and less arbitrary hydrodynamic reservoir model, which reduces probability of an incorrect evaluation of potentials of a young field or a field at an early production stage.
Development of Zone Forecast probability Models for Oil and Gas Potential in the Central Part of the Permian Uplift by Structural and Capacity Criteria
Authors:   ООО «УралОйл», Koshkin Konstantin A. , Tatarinov Ilya A. ,   ООО «НАСТ-М»
Published: April 2021

The task to which this article is devoted has not received due attention in recent years, since the preparation of structures for deep drilling is carried out using seismic exploration. At the same time, there is a huge array of data on structured drilling, unfortunately, it has not been fully used. Thus, the goal of the study is to use data on structured drilling to solve not only structural problems for marking surfaces, but also more complex ones related to zonal oil and gas potential of territories. The forecast of oil and gas content for marking and oil and gas horizons was carried out in three zones of oil and gas geological zoning. Using the data on these territories, studies were carried out to build probabilistic models for the zonal forecast of oil and gas content. To substantiate the joint use of data on marking surfaces and data on the tops of oil-bearing horizons, materials were studied for 447 deep wells. Probabilistic models of zonal forecast of oil and gas content of the central part of the Permian uplift were developed according to structural and capacity criteria. The complex use of data on the absolute marks of deep and structured wells made it possible to rank the territory of the central part of the Permian uplift by the degree of zonal oil and gas content. Severokamskoye (0.73), Krasnokamskoye (0.67), Baklanovskoye (0.67), Polaznenskoye (0.67), Rassvetnoye (0.64) and Mezhevskoye (0.63) fields were characterized by the maximum values of P COM. For the Kozubaevskoye field, the P COM was 0.57. The Gorskoye, Lobanovskoye, Talitskoye, Zorinskoye and Shemetinskoye fields were characterized by minimum values of P COM, varying in the range of 0.51–0.53. This scheme can be used when designing prospecting and exploration works in this area.
Laboratory Results of the Influence of Carbon Dioxide on the Development of the Permo-Carboniferous Reservoir of the Usinskoe Deposit
Authors:   Филиал ООО «ЛУКОЙЛ-Инжиниринг» «ПермНИПИнефть» в г. Перми, Stanislav A. Stanislav A. , Morozyuk Oleg A. ,   Филиал ООО «ЛУКОЙЛ-Инжиниринг» «ПермНИПИнефть» в г. Перми, Kosterin Konstantin S. ,   Филиал ООО «ЛУКОЙЛ-Инжиниринг» «ПермНИПИнефть» в г. Перми, Podoinitsyn Semyon P. ,   Филиал ООО «ЛУКОЙЛ-Инжиниринг» «ПермНИПИнефть» в г. Ухте
Published: April 2021

As an option for enhancing oil recovery of a high-viscosity Permo-Carboniferous reservoir associated with the Usinskoye field, the use of technology based on technogenic carbon dioxide as an injection agent is considered. In the world practice, several fields are known as close in their parameters to the parameters of the Permo-Carboniferous reservoir, and in which CO2 injection was accepted as successful. Based on this, CO2 injection can potentially be applicable in the conditions of a Permo-Carboniferous reservoir. At present, as a result of the various development technologies implementation, reservoir zones are distinguished, characterized by different thermobaric properties. Depending on reservoir conditions, when displacing oil with gases, various modes of oil displacement can be realized. This article describes the results of studies carried out to study the effect of the concentration of carbon dioxide on the properties of high-viscosity oil in the Permo-Carboniferous Reservoir of the Usinskoye field, as well as the results of filtration experiments on slim models performed to assess the oil displacement regime under various temperature and pressure conditions of the Permo-Carboniferous Reservoir. The study of the influence of CO2 concentration on oil properties was carried out using the standard PVT research technique. The displacement mode was assessed using the slim-tube technique. Based on the performed experiments, it was established that an increase in the concentration of CO2 in high-viscosity oil led to a noticeable change in its properties; for the conditions of a Permo-Carboniferous Reservoir, the most probable mode of oil displacement by carbon dioxide was established. Difficulties associated with the preparation of the CO2-heavy oil system were described separately. Based on a literature review, it was shown that the rate of mixing of oil with carbon dioxide depended on certain conditions.
Influence of Heat Treatment of Clays on Their Adsorption of Methylene Blue Dye
Authors:   Perm National Research Polytechnic University, Anyukhina Anna V. , Seredin Valerii V. ,   Perm State National Research University, Andrianov Andrey V. ,   Perm State National Research University, Khludeneva Tatiana Yu. ,   Perm State National Research University
Published: April 2021

The adsorption activity of soils largely depends on their composition and properties and, first of all, on the specific surface area and energy potential of clay particles. For the formation of "specified" properties, including adsorption, various methods of clay activation have been developed: thermal, ultraviolet, ultrasonic, mechanical, acidic, alkaline. However, despite the published data, the issues of the influence of heat treatment on the formation of the clays properties, including adsorption ones, have not been sufficiently studied. In this regard, an assessment was made of the of clays thermal activation effect on their adsorption activity for the methylene blue dye. Experimental and theoretical studies have shown that the change in the adsorption activity of clays is associated with the degree of their heat treatment. When clays are treated with temperatures up to 200° C, energy centers on the surface of structural elements are activated, which leads to an increase in the clays adsorption in terms of methylene blue by 12–24%; with an increase in the processing temperature of clays to 450–960° С, the processes of their (clays) structural transformation change, which reduces the adsorption activity of clays by 11–16 times. In addition, the influence of the clays saturation degree with water vapor on their adsorption activity has been established. During the heat treatment of clays and their partial saturation with water vapor, water molecules occupy part of the energy centers on the surface of the particles; therefore, the particles have a sufficient energy potential, which is realized in the form of high values of their adsorption to methylene blue. During the clays thermal treatment and their complete saturation with water vapor, the charges on the surface of the particles are mostly compensated by water molecules. Water molecules, entering the inter-package space, compensate charges on the surface of the packages and minerals, which are realized in the form of clay swelling processes. Swelling processes lead to an increase in the size of structural elements, which manifests itself in the form of a decrease in the specific surface of clays. Therefore, clays completely saturated with water vapor are less active adsorption than clays partially saturated with water vapor.
Results of Studying the Influence of Destroying Liquids on Polymineral Filter Cake
Authors:   Saint Petersburg Mining University, Artyom A. Artyom A. , Nikolaev Nikolay I. ,   Saint Petersburg Mining University
Published: April 2021

In the course of well construction, deterioration of the natural reservoir properties of the formation is inevitable. A dense lowpermeability filter cake formed on the surface of the bottomhole formation zone at the stage of completion contributes to a decrease in the reservoir properties of the rock, and hence the productivity of the well. In addition, the cake can contribute to the plugging of structural elements such as the well screen or inflow control devices, thereby also having a negative impact on the flow rate. In most cases, the impossibility of achieving the required cleaning of the bottomhole zone during well completion in the future leads to the need to use expensive repeated operations and overhaul, chemical and mechanical methods of cleaning the bottomhole formation zone. The development of technologies for the complete removal of the formed filter cake from the borehole walls is a necessary task. The paper considers the water-based biopolymer solution of the primary opening of the productive formation, the component composition and its parameters are given. A method is described for studying the effect of breaker systems on a polymer-mineral filter cake under high-pressure conditions using filter press HT-HP, and a method for determining the dissolving capacity of individual components of the system (chelate and enzyme). Based on the results of this study, the optimal composition of the breaker of the enzyme-chelate base was selected, after the action of which the most complete destruction of the crust constituents was observed. The results were evaluated by comparing the dissolving power of calcium carbonate when exposed to different chelates. The enzyme alpha-amylase was used as a starch breaker. The efficiency of the composition was confirmed by the change in the filtration-capacitive properties of ceramic discs before and after processing in comparison with foreign analogues of breaker systems.
Research of Temperature Conditions of Organic Sediments Formation in the Productive Formation at Paraffinic Oil Well Production
Authors:   Saint Petersburg Mining University, Sandyga Mikhail S. , Struchkov Ivan A. ,   LLC Tyumen Oil Research Center, Rogachev Mikhail K. ,   Saint Petersburg Mining University
Published: April 2021

The paper presents the studies results of the temperature conditions for the formation of organic (asphalt-resin-paraffinic) deposits in the productive formation during the downhole production of paraffinic oil, including the results of experimental studies to assess the temperature of oil saturation with paraffin in the pore space of reservoir rocks. The studies were carried out in order to substantiate and develop a technology for preventing such deposits in the "reservoir - well" system. The results of filtration and rheological studies showed that for the same oil, the wax saturation temperature in the pore space of the reservoir rock could exceed the value of this parameter in the free volume. It was found that for the investigated solutions (models of highly paraffinic oils), the phase transition of paraffin from liquid to solid state, the formation of wax crystals in the pore space occured at a temperature 3-4° C higher than in the free volume. The results of tomographic studies of the core material, performed before and after filtration of a paraffin-containing solution through it with a decrease in temperature, showed that the open porosity of rock samples decreased on average four times due to the clogging of their pore space with paraffin. Based on the results of the filtration experiment and computed tomography, a digital core model was created, which allowed modeling the fluid flow in the pore space of the rock before and after the formation of paraffin deposits in it. The calculations results of the changes dynamics in the thermal field around the injection well confirmed the probability of cooling the bottomhole zone of the well to a temperature equal to the temperature of the onset of wax crystallization, as well as the probability of the cold water front advancing to neighboring production wells, which could cause a significant decrease in the productivity due to the formation of paraffin deposits in pore space of reservoir rocks. The research results are recommended to be taken into account when developing oil fields in conditions of possible formation of organic (asphalt-resin-paraffinic) deposits in the productive formation. This will make it possible to more reliably predict and effectively prevent its formation in the "reservoir - well" system.
2020 ESC Guidelines for the management of acute coronary syndromes in patients presenting without persistent ST-segment elevation
Authors: Collet J.-P. , Thiele H. , Barbato E. , Barthélémy O. , Bauersachs J. , Bhatt D. L. , Dendale P. , Dorobantu M. , Edvardsen T. , Folliguet T. , Gale Ch. P. , Gilard M. , Jobs A. , Jüni P. , Lambrinou E. , Lewis B. S. , Mehilli Ju. , Meliga E. , Merkely B. , Mueller O. , Roffi M. , Rutten F. H. , Sibbing D. , Siontis G. C.M.
Published: April 2021

2020 ESC Guidelines for the management of acute coronary syndromes in patients presenting without persistent ST-segment elevation
Computerization of primary health care: the manager as a change agent
Authors: Gontijo Tarcísio Laerte , Lima Paola Karol Martins , Guimarães Eliete Albano de Azevedo , Oliveira Valéria Conceição de , Quites Humberto Ferreira de Oliveira , Belo Vinícius Silva , Cavancante Ricardo Bezerra
Published: April 2021

ABSTRACT Objective: To analyze factors associated with the implementation of software systems of the e-SUS Primary Care strategy in municipalities of Minas Gerais. Methods: This is a cross-sectional study conducted with municipal managers of the e-SUS Primary Care strategy. A sample of cities stratified according to population size was selected. Descriptive, bivariate, and multivariate analyzes were performed to identify factors associated with the implementation of the systems. Results: In 49.1% (95%CI: 39.5-58.8) of the municipalities investigated, some of the e-SUS Primary Care systems were implemented. Time working as a strategy manager (OR: 3.03) and training for Primary Care professionals in the municipality (OR: 2.28) were associated with the implementation of the systems. Conclusion: The presence of a trained manager leading the implementation process impacted the implementation of the e-SUS AB strategy software systems in the municipalities of Minas Gerais. It is also essential to highlight the need to improve the technological infrastructure for the computerization of Primary Care.