814 research outputs found
T2–T2 exchange in biofouled porous media
Recent two dimensional nuclear magnetic resonance (NMR) techniques access exchange in pore structures through surface relaxation and diffusion based relaxation [1-4]. This research applies these techniques to measure pore changes due to biofilm growth and the impact this growth has on diffusion transport. The porous media used in this study are model beadpacks constructed from borosilicate glass beads with diameters approximately 100 um. This research shows that through changes in the relaxation rates, NMR can be used to verify biofilm growth in porous media
New insights into the thermal behaviour of organic ionic plastic crystals: magnetic resonance imaging of polycrystalline morphology alterations induced by solid-solid phase transitions
Organic ionic plastic crystals (OIPCs) show strong potential as solid-state electrolytes for lithium battery applications, demonstrating promising electrochemical performance and eliminating the need for a volatile and flammable liquid electrolyte. The ionic conductivity (σ) in these systems has recently been shown to depend strongly on polycrystalline morphology, which is largely determined by the sample\u27s thermal history. [K. Romanenko et al., J. Am. Chem. Soc., 2014, 136, 15638]. Tailoring this morphology could lead to conductivities sufficiently high for battery applications, so a more complete understanding of how phenomena such as solid-solid phase transitions can affect the sample morphology is of significant interest. Anisotropic relaxation of nuclear spin magnetisation provides a new MRI based approach for studies of polycrystalline materials at both a macroscopic and molecular level. In this contribution, morphology alterations induced by solid-solid phase transitions in triisobutyl(methyl)phosphonium bis(fluorosulfonyl)imide (P1444FSI) and diethyl(methyl)(isobutyl)phosphonium hexafluorophosphate (P1224PF6) are examined using magnetic resonance imaging (MRI), alongside nuclear magnetic resonance (NMR) spectroscopy, diffusion measurements and conductivity data. These observations are linked to molecular dynamics and structural behaviour crucial for the conductive properties of OIPCs. A distinct correlation is established between the conductivity at a given temperature, σ(T), and the intensity of the narrow NMR signal that is attributed to a mobile fraction, fm(T), of ions in the OIPC. To explain these findings we propose an analogy with the well-studied relationship between permeability (k) and void fraction (θ) in porous media, with k(θ) commonly quantified by a power-law dependence that can also be employed to describe σ(fm)
Managing Coal Enterprise Competitiveness in the Context of Global Challenges
Increased geopolitical tensions and economic sanctions imposed by the U.S., the European Union, and other countries against Russian sectors of the economy have caused a slowdown of economic growth in Russia and significantly restricted access to international capital markets, creating many problems for coal enterprises due to the rapid growth of competition. Russian and Indonesian coal companies need to adopt coping strategies and implement effective management practices to successfully counter the various global challenges facing the coal sector. The article aims to develop coal enterprise competitiveness management in the context of global challenges in 2022, as exemplified by Russia and Indonesia, considering the main role of these two countries in global coal exports. The management process was empirically assessed, and a comprehensive qualitative focus group session was conducted to achieve this goal. Fifty-five top managers of Russian and Indonesian coal companies participated in the focus group session to collect data for identifying all the factors and indicators to be accounted for in a holistic assessment of the companies’ competitiveness. Suggestions were worked out for the development of coal companies in Russia and Indonesia, regarding current changes, to increase their competitiveness. Doi: 10.28991/ESJ-2023-07-02-021 Full Text: PD
Analyses of the stress intensity of the cylindrical tank wall at the place of the geometrical defect
Major repair or regular inspection of the large capacity thin‐walled tankages is very expensive. Steel cylindrical tanks are an individual case of the thin‐walled tankages. The common calculation of the tanks by analytical and numerical methods is not difficult. Strengthening the places, where a perfect calculated form is disturbed, that is, at the spots of in‐cuts, hatches, defects etc. is a responsible part of the design of such constructions. The problems of prevention of defects during the operation period and repairs, as well as possibility to assure quickly the safety of defective places of the constructions are more important than the common calculations. The main objective of the presented investigations is to identify stress/strain state of the wall tank with local imperfections from the ideal cylindrical surface, taking into account the membrane theory of the shells by using the finite element's method.
Santrauka
Didelio tūrio statiniu remontai arba net profilaktines apžiūros yra gana brangūs procesai. Metalines cilindrines talpyklos priskiriamos prie atskiros tūriniu plonasieniu konstrukciju grupes. Talpyklu reguliariu konstrukciju analitiniai ar skaitiniai skaičiavimai nera sudetingi. Bet tokiu vietu, kaip konstrukciju jungčiu bei technologines irangos prijungimo projektavi‐mas ar konstrukciju defektu analize yra gerokai svarbesne projektavimo dalis. Defektu prevencija naudojant talpyklas, taip pat defektuotu vietu sustiprinimas yra svarbesnis nei bendrieji talpyklu skaičiavimai. Šio darbo tikslas ‐ nustatyti realaus objekto cilindrines talpyklos sieneles su geometrinemis lokaliomis nuokrypomis itempiu ir deformaciju būvi pagal memb‐ranine kevalu skaičiavimo teorija, taikant baigtiniu elementu metoda.
First Published Online: 24 Jun 2011
Reikšminiai žodžiai: plienine cilindrine talpykla, defektas, skaitinis modelis, baigtinis elementas, itempiu ir deformaciju būvi
Післятравматичні деформації кісток, що утворюють колінний суглоб: загальний аналіз і лікувальна тактика
The aim of paper: to provide modern approach to diagnostics and treatment of deformities localized around knee joint and developed after distal metadiaphysis of femur and proximal metadiaphysis of tibia fractures. It was shown, that formed deformities provoke development of secondary adaptive changes in articular surfaces of knee and its stabilizers, thigh and shin muscles. It also impairs walking. The planning of treatment should be based on proper investigation: radiologic assessment of malaligned extremity and its computer tomography, ultrasound investigation of tendons and muscles, that provide function of knee joint, assess anatomic-functional characteristics of knee joint itself (range of motion, stability, osteoarthritic changes) and malfunction of whole extremity with malaligned segment, including walking ability. Standardized technique of roentgenographic investigation and standard parameters for proper image analysis are provided. The necessity to take into consideration all changes of impaired extremity and segment, but not only the results of roentgenograms assessment, for the working-out of treatment is emphasized. The main treatment goals are: restoration of weight-bearing ability, anatomic or almost anatomic realignment to restore three-dimension orientation of articular surfaces, improvement of walking function. The main types of treatment are: different osteotomies followed with fragments fixation using extrafocal or buried osteosynthesis (intramedullary nailing or plating), restoration of ligamentous structures, arthroplasty or arthrodesis. Main indications for every variant of surgical intervention are listed.Цель работы: предоставить современный взгляд на диагностику и лечение деформаций, локализирующихся в области коленного сустава и развившихся после переломов дистального метадиафиза бедренной кости или проксимального большеберцовой.Показано, что сформировавшиеся деформации приводят к развитию вторичных адаптационных изменений в артикулирующих поверхностях коленного сустава, его стабилизаторах, мышцах бедра и голени, влияют на функцию ходьбы. При планировании лечебной тактики этих пациентов следует провести рентгенологическую оценку деформированной конечности, анализ данных компьютерной томографии, стабилографии и статографии, ультразвукового исследования мышц и сухожилий, обеспечивающих движения в коленном суставе, оценить его анатомо-функциональные характеристики (объем движений, стабильность, артрозные изменения), нарушение функции конечности с деформированным сегментом, включая функцию ходьбы. Представлена стандартизированная методика рентгенологического исследования и рентгенологические параметры для адекватного анализа снимков. Подчеркнуто, что при планировании лечебной тактики необходимо учитывать все изменения поврежденного сегмента и конечности, а не только результаты анализа рентгенограмм. Основные задачи лечения — это восстановление возможности осевой нагрузки массой тела, анатомическая или почти анатомическая коррекция осевых взаимоотношений для получения нормальной пространственной ориентации суставных поверхностей, улучшение функции ходьбы. Основными видами хирургических вмешательств являются: различные виды остеотомий с последующей коррекцией (одномоментной или постепенной) и фиксацией фрагментов с применением методики внеочагового или погружного остеосинтеза (интрамедуллярный блокированный или накостный); вмешательства на связочных структурах; эндопротезирование; артродезирование. Сформулированы основные показания для каждого из видов оперативного вмешательства.Мета роботи: надати сучасний погляд на діагностику та лікування деформацій, які локалізуються в ділянці колінного суглоба та розвинулися після переломів дистального метадіафіза стегнової кістки або проксимального великогомілкової.Показано, що сформовані деформації призводять до розвитку вторинних адаптаційних змін в артикулюючих поверхнях колінного суглоба, його стабілізаторах, м’язах стегна та гомілки, впливають на функцію ходьби. Під час планування лікувальної тактики цих пацієнтів слід провести рентгенологічне оцінювання деформованої кінцівки, аналіз даних комп’ютерної томографії, стабілографії та статографіі, ультразвукового дослідження м’язів і сухожилків, які забезпечують рух у колінному суглобі, оцінити його анатомо-функціональні характеристики (обсяг рухів, стабільність, артрозні зміни), порушення функції кінцівки з деформованим сегментом, включаючи функцію ходьби. Представлена стандартизована методика рентгенологічного дослідження та рентгенологічні параметри для адекватного аналізу знімків. Підкреслено, що під час планування лікувальної тактики необхідно враховувати всі зміни ушкодженого сегмента і кінцівки, а не лише результати аналізу рентгенограм. Основні завдання лікування — це відновлення можливості осьового навантаження масою тіла, анатомічна або майже анатомічна корекція осьових взаємовідношень для отримання нормальної просторової орієнтації суглобових поверхонь, поліпшення функції ходьби. Основними видами хірургічних втручань є: різні види остеотомій із подальшою корекцією (одночасною або поступовою) і фіксацією фрагментів зі застосуванням методики позавогнищевого або заглибного остеосинтезу (інтрамедулярний блокований або накістковий); втручання на зв’язкових структурах; ендопротезування; артродезування. Сформульовано основні показання для кожного з видів оперативного втручання
Posttraumatic deformities of the bones, forming knee joint: general evaluation and treatment tactics
Binarization of soil X-ray tomography images: revisiting Otsu’s method
<p>In numerous applications the most critical step between studying soil structure with the help of X-ray tomography and its quantitative analysis is image segmentation; the simplest type is a division of the gray-scale images into solids and pores – or binarization, is necessary to perform pore-scale simulations (Gerke et al.,2018). This can be performed by either manual or automatic methods. Current state-of-the-art methods mainly include so called local segmentation where for each two phases one needs two confidence thresholds, i.e., 100% pores and 100% solids for binarization. These thresholds are either chosen manually (Karsanina et al.,2018) or automatically, the pixels/voxels in between these thresholds are classified according to some statistical measure or by growing phases from seeds. In case of global methods there is a single threshold that divides the histogram into pores and solids explicitly. There is, however, a class of popular automatic global/local methods based on gray-scale image variance minimization – Otsu’s method and its variations (Hapca et al.,2013), numerous related techniques are available in popular image processing software – ImageJ and SoilJ (Koestel,2018). The aims of our work to test Otsu-based techniques applicability to various soils and imaging resolutions.</p><p>In our study, we compared the results of using different variations of Otsu’s method working for 2D and fully 3D images for a number of soil samples of different sizes and taken at different resolutions: 240, 100, 16, 1µm. The largest samples - monoliths with a diameter of 10 cm were taken with the coarsest resolution, mesopores were segmented in micromonoliths with a diameter of 2 cm, with the most detailed resolution the pore space of microaggregates was investigated and segmented (fraction 2-1 mm). All objects of study have individual characteristics.</p><p>According to the results of the study, it can be argued that the Otsu method (3D) with a high degree of reliability worked only for detailed images of microaggregates. Its usage for all soils is generally unacceptable, as we observed for all other samples studied here. Moreover, automatic Otsu and related methods do not perform satisfactory on images with histograms resembling highly hierarchical structures (Gerke et al.,2015), which is true for all structured soils (Karsanina et al.,2018).</p><p>This research was supported by the RSF grant 19-74-10070.</p><p>References:</p><p>Karsanina, M.V., Gerke, K.M., Skvortsova, E.B., Ivanov, A.L., & Mallants,D.(2018). Enhancing image resolution of soils by stochastic multiscale image fusion. Geoderma,314, 138-145.</p><p>Gerke, K.M., Karsanina, M.V., & Mallants, D. (2015). Universal stochastic multiscale image fusion: an example application for shale rock. Scientific reports,5, 15880.</p><p>Hapca, S.M., Houston, A.N., Otten, W., & Baveye, P.C. (2013). New local thresholding method for soil images by minimizing grayscale intra-class variance. Vadose Zone Journal,12(3).</p><p>Gerke, K.M., Vasilyev, R.V., Khirevich, S., Collins, D., Karsanina, M.V., Sizonenko, T.O., Korost D.V., Lamontagne S., & Mallants, D.(2018). Finite-difference method Stokes solver (FDMSS) for 3D pore geometries: Software development, validation and case studies. Computers & Geosciences, 114, 41-58</p><p>Koestel, J.(2018). SoilJ: an ImageJ plugin for the semiautomatic processing of three-dimensional X-ray images of soils. Vadose Zone Journal,17(1).</p>
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Numerical modeling of Surface-Scan MRI experiments for improved diagnostics of commercial battery cells
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