scholarly journals On the determination of the voltage field in the eccentric tube, from an aging elasticplastic material

2020 ◽  
pp. 93-100
Author(s):  
Дмитрий Викторович Гоцев ◽  
Алексей Викторович Ковалев ◽  
Александр Иванович Шашкин ◽  
Александр Юрьевич Яковлев
Keyword(s):  
Analytical Form ◽  
Pipe Material ◽  
Elastoplastic Properties ◽  
Stress Components ◽  
History Of ◽  
Eccentric Tube ◽  
Distribution Of Stress ◽  
Analytical Expressions ◽  
Elastoplastic Stress State

В работе в ананлитическом виде определяется распределение полей напряжений в эксцентрической трубе, находящейся под действием внутреннего давления. Материал трубы моделировался средой, обладающей наследственно стареющими упругопластическими свойствами. Решение задачи проводилось в рамках метода возмущений. За малый параметр бралась величина эксцентриситета. В качестве невозмущенного состояния принималось осесимметричное упругопластическое напряженное состояние трубы, определенное с учетом возраста и истории нагружения материала. В результате моделирования выведено уравнение для определения формы и размера границы раздела упругой и пластичесой зон в трубе с эксцентриситетом, а также получены аналитические выражения для компонент напряжений в каждой из областей деформирования. In this work, the distribution of stress fields in an eccentric pipe under the action of internal pressure is determined in an analytical form. The pipe material was modeled by a medium with hereditarily aging elastoplastic properties. The problem was solved within the framework of the perturbation method. The eccentricity value was taken as a small parameter. The unperturbed state was taken to be the axisymmetric elastoplastic stress state of the pipe, determined taking into account the age and loading history of the material. As a result of modeling, an equation was derived to determine the shape and size of the interface between the elastic and plastic zones in a pipe with eccentricity, and analytical expressions were obtained for the stress components in each of the deformation regions.

Exact determination of critical damping in multiple exponential kernel-based viscoelastic single-degree-of-freedom systems

2019 ◽  
Vol 24 (12) ◽  
pp. 3843-3861 ◽  
Author(s):  
Mario Lázaro
Keyword(s):  
Past History ◽  
Degree Of Freedom ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Critical Curves ◽  
History Of ◽  
Definition Of ◽  
Analytical Expressions ◽  
Critical Damping

In this paper, exact closed forms of critical damping manifolds for multiple-kernel-based nonviscous single-degree-of-freedom oscillators are derived. The dissipative forces are assumed to depend on the past history of the velocity response via hereditary exponential kernels. The damping model depends on several parameters, considered variables in the context of this paper. Those parameter combinations which establish thresholds between induced overdamped and underdamped motion are called critical damping manifolds. If such manifolds are represented on a coordinate plane of two damping parameters, then they are named critical curves, so that overdamped regions are bounded by them. Analytical expressions of critical curves are deduced in parametric form, considering certain local nondimensional parameters based on the Laplace variable in the frequency domain. The definition of the new parameter (called the critical parameter) is supported by several theoretical results. The proposed expressions are validated through numerical examples showing perfect fitting of the determined critical curves and overdamped regions.

scholarly journals Determination of the stress state of a hardening disk under the influence of temperature

2020 ◽  
pp. 168-173
Author(s):  
Мария Михайловна Вислогузова ◽  
Дмитрий Викторович Гоцев ◽  
Алексей Викторович Ковалев ◽  
Александр Иванович Шашкин
Keyword(s):  
Displacement Vector ◽  
Analytical Form ◽  
Radial Component ◽  
Inelastic Behavior ◽  
Small Perturbations ◽  
Flat Disk ◽  
Elastoplastic Boundary ◽  
Distribution Of Stress ◽  
Elastic And Plastic Deformation

Как известно при нагревании твердые тела, в частности металлы, испытывают температурные деформации, связанные с эффектом линейного расширения. При этом, несмотря на то, что эти деформации малы, соответствующие им напряжения могут оказаться достаточно большими, зачастую превосходящими предел текучести материала. В связи с этим для описания напряженно-деформированных состояний тел, находящихся под действием высоких температур, необходимо учитывать неупругое поведение материалов. Определению напряжений и деформаций в упругопластических задачах посвящено множество работ, в том числе исследования [1-10]. В некоторых из них [1], [5-10] рассматривается температурное воздействие на тела различной конфигурации. В настоящей работе решается задача об определении осесимметричного поля напряжений в плоском диске при воздействии на него точечного источника тепла (например, точечная сварка). Материал диска моделируется упрочняющейся упругопластической средой. Задача решалась в рамках плоско-напряженного состояния методом малых возмущений. В аналитическом виде получены соотношения, описывающие распределение полей напряжений в упругой и пластической областях деформирования. В качестве условий сопряжения решений на упругопластической границе использовались условия неразрывности радиальной и окружной компонент тензора напряжений и радиальной компоненты вектора перемещений. As you know, when heated, solids, in particular metals, experience thermal deformations associated with the effect of linear expansion. Moreover, in spite of the fact that these strains are small, the corresponding stresses can be quite large, often exceeding the yield stress of the material. In this regard, to describe the stress-strain states of bodies exposed to high temperatures, it is necessary to take into account the inelastic behavior of materials. Determination of stresses and strains in elastoplastic problems has been the subject of many works, including studies [1-10]. Some of them [1], [5-10] consider the temperature effect on bodies of various configurations. In this work, we solve the problem of determining the axisymmetric stress field in a flat disk when exposed to a point heat source (for example, spot welding). The disc material is modeled by a hardening elastoplastic medium. The problem was solved within the plane-stressed state by the method of small perturbations. In an analytical form, relations are obtained that describe the distribution of stress fields in elastic and plastic deformation regions. The conditions of continuity of the radial and circumferential components of the stress tensor and the radial component of the displacement vector were used as conditions for conjugation of solutions on the elastoplastic boundary.

State-by-State Use of AMA Guides

2019 ◽  
Vol 24 (5) ◽  
pp. 3-7, 16
Keyword(s):  
Expert Testimony ◽  
Narrow Range ◽  
The United States ◽  
Workers Compensation ◽  
Federal Employees ◽  
Permanent Disability ◽  
Sixth Edition ◽  
History Of ◽  
Canadian Provinces

Abstract This article presents a history of the origins and development of the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), from the publication of an article titled “A Guide to the Evaluation of Permanent Impairment of the Extremities and Back” (1958) until a compendium of thirteen guides was published in book form in 1971. The most recent, sixth edition, appeared in 2008. Over time, the AMA Guides has been widely used by US states for workers’ compensation and also by the Federal Employees Compensation Act, the Longshore and Harbor Workers’ Compensation Act, as well as by Canadian provinces and other jurisdictions around the world. In the United States, almost twenty states have developed some form of their own impairment rating system, but some have a narrow range and scope and advise evaluators to consult the AMA Guides for a final determination of permanent disability. An evaluator's impairment evaluation report should clearly document the rater's review of prior medical and treatment records, clinical evaluation, analysis of the findings, and a discussion of how the final impairment rating was calculated. The resulting report is the rating physician's expert testimony to help adjudicate the claim. A table shows the edition of the AMA Guides used in each state and the enabling statute/code, with comments.

Integrative Approach in Law Understanding: the History of the Origin of Ideas and the Current State

2020 ◽  
Vol 2 (1) ◽  
pp. 115-130
Author(s):  
R. R. Palekha ◽  
Keyword(s):  
Central Place ◽  
Scientific Basis ◽  
Integrative Approach ◽  
Current State ◽  
History Of ◽  
Legal Thinking ◽  
Reliable Knowledge ◽  
The Right ◽  
Fat Formulation

Introduction. Right understanding is the most live, interesting and, at the same time, the uncertain and changeable area of researches which takes the central place as in the general theory of the right, and gains the increasing value in industry jurisprudence that is connected with its considerable teoretiko-methodological and applied potential which is shown in spheres of lawmaking and law-enforcement activity. Thus, right understanding represents research tools of the subject of knowledge which allow to study all range legal and, the based on them, state phenomena for the purpose of obtaining reliable knowledge of state and legal reality. In this regard integrative approach in right understanding which has rich history of the formation and development is of special interest, allows to perceive the right as integrally complete phenomenon, as much as possible retrieves its regulatory abilities and, provides achievement of criteria of scientific research: comprehensiveness, objectivity, historicism. Materials and Methods. In article an attempt of the analysis of integrative approach in right understanding from a position of history of origin of his ideas and assessment of the current state is made. A result of studying of scientific literature, generalization and comparison of the different points of view fat formulation of author’s determination of category “right understanding” and submission of the evidence-based integrative theory of right understanding which as much as possible conforms to requirements of time and has essential regulatory and guarding potential. Results. In article the category right understanding is comprehensively considered, different integrative theories of right understanding from a position of their origin and development are submitted, the value of modern integrative approach in right understanding is shown, perspectives of its further development are evaluated. Discussion and Conclusion. The author comes to the conclusion about the theoretical and methodological consistency and inevitability of the integrative approach in law understanding, which acts as a scientifically grounded type of legal thinking capable of comprehending the law on a truly scientific basis.

Diagnostics of the location of damage to tubing oil well pipes

2019 ◽  
Vol 5 (4) ◽  
pp. 115-128
Author(s):  
Timur A. Ishmuratov ◽  
Rif G. Sultanov ◽  
Milyausha N. Khusnutdinova
Keyword(s):  
Fluid Motion ◽  
Oil Well ◽  
General Belief ◽  
Oil Flow ◽  
Specialized Equipment ◽  
Improving Accuracy ◽  
Analytical Expressions ◽  
Technical Measures ◽  
Quick Determination

The study is devoted to the mathematical description of the process of oil outflow in places of leakage of the tubing string, which allows a computer to locate a leakage in the tubing. The authors propose methodology for identifying defects in the tubing and determining the location of the leak. The uniqueness of this methodology lies in quick determination of the place of leakage without the use of specialists, sophisticated and specialized equipment. Mathematical modeling of oil flow in the tubing requires the apparatus of continuum mechanics. It is a general belief that the movement of oil in the pipe flows at low speeds due to its outflow from the hole. Using the general equations of mass and energy balance, the authors have obtained differential equations of fluid motion in a vertical pipe in the process of its outflow from the tubing and in the process of injection. Analytical expressions are the solution to these equations, as they can help in estimating the degree of damage and its location, as well as the feasibility of its eliminating. The results show that an increase in the leakage and injection times leads to improving accuracy of locating damage. Thus, when conducting various geological and technical measures (GTM) at the well, it is possible to assess the presence of leakage and its intensity when deciding on the repair of tubing.

scholarly journals In Situ exploration of the giant planets

2021 ◽  
Author(s):  
O. Mousis ◽  
D. H. Atkinson ◽  
R. Ambrosi ◽  
S. Atreya ◽  
D. Banfield ◽  
...  
Keyword(s):  
Solar System ◽  
Giant Planets ◽  
Atmospheric Composition ◽  
Formation History ◽  
History Of ◽  
Composition Structure ◽  
Galileo Probe ◽  
Probe Measurements

AbstractRemote sensing observations suffer significant limitations when used to study the bulk atmospheric composition of the giant planets of our Solar System. This impacts our knowledge of the formation of these planets and the physics of their atmospheres. A remarkable example of the superiority of in situ probe measurements was illustrated by the exploration of Jupiter, where key measurements such as the determination of the noble gases’ abundances and the precise measurement of the helium mixing ratio were only made available through in situ measurements by the Galileo probe. Here we describe the main scientific goals to be addressed by the future in situ exploration of Saturn, Uranus, and Neptune, placing the Galileo probe exploration of Jupiter in a broader context. An atmospheric entry probe targeting the 10-bar level would yield insight into two broad themes: i) the formation history of the giant planets and that of the Solar System, and ii) the processes at play in planetary atmospheres. The probe would descend under parachute to measure composition, structure, and dynamics, with data returned to Earth using a Carrier Relay Spacecraft as a relay station. An atmospheric probe could represent a significant ESA contribution to a future NASA New Frontiers or flagship mission to be launched toward Saturn, Uranus, and/or Neptune.

scholarly journals Anaphylactic Death: A New Forensic Workflow for Diagnosis

Healthcare ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 117
Author(s):  
Massimiliano Esposito ◽  
Angelo Montana ◽  
Aldo Liberto ◽  
Veronica Filetti ◽  
Nunzio Di Nunno ◽  
...  
Keyword(s):  
Clinical History ◽  
Rapid Onset ◽  
Mean Value ◽  
Laryngeal Edema ◽  
Tryptase Level ◽  
Antibody Staining ◽  
Life Threatening ◽  
History Of ◽  
Immunohistochemical Techniques

Anaphylaxis is a life-threatening or fatal clinical emergency characterized by rapid onset, and death may be sudden. The margin of certainty about the diagnosis of anaphylactic death is not well established. The application of immunohistochemical techniques combined with the evaluation of blood tryptase concentrations opened up a new field of investigation into anaphylactic death. The present study investigated eleven autopsy cases of anaphylactic death, carried out between 2005 and 2017, by the Departments of Forensic Pathology of the Universities of Foggia and Catania (Italy). An analysis of the medical records was carried out in all autopsies. Seven autopsies were carried out on males and four on females. Of the eleven cases, one showed a history of asthma, one of food ingestion, two of oral administration of medications, six did not refer any allergy history, and one subject was unknown. All cases (100%) showed pulmonary congestion and edema; 7/11 (64%) of the cases had pharyngeal/laryngeal edema and mucus plugging in the airway; only one case (9%) had a skin reaction that was found during external examination. Serum tryptase concentration was measured in ten cases, and the mean value was 133.5 µg/L ± 177.9. The immunohistochemical examination using an anti-tryptase antibody on samples from the lungs, pharynx/larynx, and skin site of medication injection showed that all cases (100%) were strongly immunopositive for anti-tryptase antibody staining on lung samples; three cases (30%) were strongly immunopositive for anti-tryptase antibody staining on pharyngeal/laryngeal samples; and eight cases (80%) were strongly immunopositive for anti-tryptase antibody staining on skin samples. We conclude that a typical clinical history, blood tryptase level >40 µg/L, and strongly positive anti-tryptase antibody staining in the immunohistochemical investigation may represent reliable parameters in the determination of anaphylactic death with the accuracy needed for forensic purposes.

scholarly journals Gaia DR1 completeness within 250 pc & star formation history of the Solar neighbourhood

2017 ◽  
Vol 12 (S330) ◽  
pp. 148-151 ◽  
Author(s):  
Edouard J. Bernard
Keyword(s):  
Star Formation ◽  
Star Formation History ◽  
Solar Neighbourhood ◽  
The Sun ◽  
Thick Disc ◽  
Formation History ◽  
Magnitude Diagram ◽  
History Of

AbstractWe took advantage of the Gaia DR1 to combine TGAS parallaxes with Tycho-2 and APASS photometry to calculate the star formation history (SFH) of the solar neighbourhood within 250 pc using the colour-magnitude diagram fitting technique. We present the determination of the completeness within this volume, and compare the resulting SFH with that calculated from the Hipparcos catalogue within 80 pc of the Sun. We also show how this technique will be applied out to ~5 kpc thanks to the next Gaia data releases, which will allow us to quantify the SFH of the thin disc, thick disc and halo in situ, rather than extrapolating based on the stars from these components that are today in the solar neighbourhood.

scholarly journals Mineralogy and Geochemistry of Ultramafic Rocks from Rachoni Magnesite Mine, Gerakini (Chalkidiki, Northern Greece)

Minerals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 934
Author(s):  
Evangelos Tzamos ◽  
Micol Bussolesi ◽  
Giovanni Grieco ◽  
Pietro Marescotti ◽  
Laura Crispini ◽  
...  
Keyword(s):  
Raw Materials ◽  
Mining Area ◽  
Ultramafic Rocks ◽  
Northern Greece ◽  
Icp Ms ◽  
Time In Literature ◽  
History Of ◽  
First Time ◽  
The Eu

The importance of magnesite for the EU economy and industry is very high, making the understanding of their genesis for the exploration for new deposits a priority for the raw materials scientific community. In this direction, the study of the magnesite-hosting ultramafic rocks can be proved very useful. For the present study, ultramafic rock samples were collected from the magnesite ore-hosting ophiolite of the Gerakini mining area (Chalkidiki, Greece) to investigate the consecutive alteration events of the rocks which led to the metallogenesis of the significant magnesite ores of the area. All samples were subjected to a series of analytical methods for the determination of their mineralogical and geochemical characteristics: optical microscopy, XRD, SEM, EMPA, ICP–MS/OES and CIPW normalization. The results of these analyses revealed that the ultramafic rocks of the area have not only all been subjected to serpentinization, but these rocks have also undergone carbonation, silification and clay alteration. The latter events are attributed to the circulation of CO2-rich fluids responsible for the formation of the magnesite ores and locally, the further alteration of the serpentinites into listvenites. The current mineralogy of these rocks was found to be linked to one or more alteration event that took place, thus a significant contribution to the metallo- and petrogenetic history of the Gerakini ophiolite has been made. Furthermore, for the first time in literature, Fe inclusions in olivines from Greece were reported.

‘Planets’ in Simplicius De caelo 471.1 ff.

1971 ◽  
Vol 91 ◽  
pp. 138-139 ◽  
Author(s):  
J. J. Hall
Keyword(s):  
Greek Philosophy ◽  
History Of

In four of the last five numbers of the JHS, Doctors D. R. Dicks and D. O'Brien have disputed about Simplicius De caelo 471.1 ff. (DK 12A19), which runs (in part, 471.2–6): καὶ γὰρ ἐκεῑ [i.e. ἐκ τῶν περὶ ἀστρολογίαν] περὶ τῆς τάξεως τῶν πλανωμένων καὶ περὶ μεγεθῶν καὶ ἀποστημάτων ἀποδέδεικται Ἀναξιμάνδρου πρώτου τὸν περὶ μεγεθῶν καὶ ἀποστημάτων λόγον εὑρηκότος, ὡς Εὔδημος ἱστορεῖ τὴν τῆς θέσεως τάξιν εἰς τοὺς Πυθαγορείους πρώτους ἀναψέρων. In his History of Greek philosophy (i 93), Professor Guthrie translates the latter part of this as follows: ‘(…speaking of the planets) “Anaximander was the first to discuss their sizes and distances, according to Eudemus, who attributes the first determination of their order to the Pythagoreans.”’ Guthrie, Dicks and O'Brien all agree that πλανωμένων is accurately translated as ‘planets’; they also evidently agree that Anaximander would not have distinguished the planets from the fixed stars, at least in this matter; and consequently Guthrie (op. cit. i 95) finds Simplicius' statement about Anaximander ‘confusing’; Dicks finds it ‘nonsensical’; and O'Brien speaks of Simplicius' ‘rather ragged context’, and supposes that Eudemus was actually speaking, not of planets, but of sun, moon and stars, i.e. that Simplicius has quite misrepresented his source.

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