Готові списки джерел за темами / Non-Closed fields

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Добірка наукової літератури з теми "Non-Closed fields"

Автор: Grafiati

Опубліковано: 8 березня 2025

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Статті в журналах з теми "Non-Closed fields"

Abramovich, Dan, Jan Denef, and Kalle Karu. "Weak toroidalization over non-closed fields." Manuscripta Mathematica 142, no. 1-2 (April 10, 2013): 257–71. http://dx.doi.org/10.1007/s00229-013-0610-5.

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Ballico, E. "Line Bundles and Non-Algebraically Closed Fields." Rocky Mountain Journal of Mathematics 23, no. 2 (June 1993): 447–50. http://dx.doi.org/10.1216/rmjm/1181072570.

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Sanford, Sean. "Fusion categories over non-algebraically closed fields." Journal of Algebra 663 (February 2025): 316–51. http://dx.doi.org/10.1016/j.jalgebra.2024.09.010.

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Wagner, Frank O. "Minimal fields." Journal of Symbolic Logic 65, no. 4 (December 2000): 1833–35. http://dx.doi.org/10.2307/2695078.

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Kuznetsov, Alexander, and Yuri Prokhorov. "Rationality of Fano threefolds over non-closed fields." American Journal of Mathematics 145, no. 2 (April 2023): 335–411. http://dx.doi.org/10.1353/ajm.2023.0008.

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Gamboa, J. M. "A note on cohomology over non algebraically closed fields." Bulletin of the Australian Mathematical Society 60, no. 1 (August 1999): 67–72. http://dx.doi.org/10.1017/s0004972700033335.

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Geyer, Wulf-Dieter, and Moshe Jarden. "Non-pac fields whose Henselian closures are seperably closed." Mathematical Research Letters 8, no. 4 (2001): 509–19. http://dx.doi.org/10.4310/mrl.2001.v8.n4.a10.

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Turki, Nasser Bin, Sharief Deshmukh, and Olga Belova. "A note on closed vector fields." AIMS Mathematics 9, no. 1 (2023): 1509–22. http://dx.doi.org/10.3934/math.2024074.

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<abstract><p>Special vector fields, such as conformal vector fields and Killing vector fields, are commonly used in studying the geometry of a Riemannian manifold. Though there are Riemannian manifolds, which do not admit certain conformal vector fields or certain Killing vector fields, respectively. Closed vector fields exist in abundance on each Riemannian manifold. In this paper, we used closed vector fields to study the geometry of the Riemannian manifold. In the first result, we showed that a compact Riemannian manifold $ (M^{n}, g) $ admits a closed vector field $\boldsymbol{\omega }$ with $ \mathrm{div} \boldsymbol{\omega }$ non-constant and an eigenvector of the rough Laplace operator, the integral of the Ricci curvature $ Ric(\boldsymbol{\omega }, \boldsymbol{\omega }) $ has a suitable lower bound that is necessarily isometric to $ S^{n}(c) $ and that the converse holds. In the other result, we found a characterization of an Euclidean space using a closed vector field $\boldsymbol{\omega }$ with non-constant length that annihilates the rough Laplace operator and squared length of its covariant derivative that has a suitable upper bound. Finally, we used the closed vector field provided by the gradient of the non-trivial solution of the Fischer-Marsden equation on a complete and simply connected Riemannian manifold $ (M, g) $ and showed that it is necessary and sufficient for $ (M, g) $ to be isometric to a sphere and that the squared length of the covariant derivative of this closed vector field has a suitable upper bound.</p></abstract>

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Evans, David M. "Expansions of fields by angular functions." Journal of the Institute of Mathematics of Jussieu 7, no. 4 (October 2008): 735–50. http://dx.doi.org/10.1017/s1474748008000200.

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AbstractThe notion of an angular function has been introduced by Zilber as one possible way of connecting non-commutative geometry with two ‘counterexamples’ from model theory: the non-classical Zariski curves of Hrushovski and Zilber, and Poizat's field with green points. This article discusses some questions of Zilber relating to existentially closed structures in the class of algebraically closed fields with an angular function.

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Cluckers, R., L. Lipshitz, and Z. Robinson. "Real closed fields with non-standard and standard analytic structure." Journal of the London Mathematical Society 78, no. 1 (May 13, 2008): 198–212. http://dx.doi.org/10.1112/jlms/jdn024.

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Більше джерел

Дисертації з теми "Non-Closed fields"

Alessandrini, Daniele. "A tropical compactification for character spaces of convex projective structures." Doctoral thesis, Scuola Normale Superiore, 2007. http://hdl.handle.net/11384/85709.

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Boitrel, Aurore. "Groupes d'automorphismes des surfaces del Pezzo sur un corps parfait." Electronic Thesis or Diss., université Paris-Saclay, 2025. http://www.theses.fr/2025UPASM002.

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Les surfaces del Pezzo sont des surfaces algébriques dotées de propriétés particulières, et qui jouent un rôle important dans la classification des surfaces algébriques projectives à transformations birationnelles près.La classification des surfaces del Pezzo rationnelles et lisses de degré d sur un corps parfait arbitraire est classique pour d = 7, 8, 9 et nouvelle pour d = 6. Il en va de même pour ladescription de leurs groupes d'automorphismes. Leur classification et la description de leursgroupes d'automorphismes sont beaucoup plus difficiles pour d ≤ 5, comme on peut déjà le voir si le corps de base est le corps des nombres réels, et la classification est ouverte sur un corps parfait général. Des classifications partielles existent sur des corps finis. Par conséquent, nous ne connaissons pas leurs groupes d'automorphismes en général.L'objectif de la thèse est de classifier les surfaces del Pezzo rationnelles lisses de degréd = 5 et d = 4 sur un corps parfait arbitraire et de décrire leurs groupes d'automorphismes.En raison de la difficulté du projet, le cas d = 4 ne sera étudié que sur le corps des nombres réels
Del Pezzo surfaces are algebraic surfaces with quite special properties, that play an importantpart in the classification of projective algebraic surfaces up to birational transformations.The classification of smooth rational del Pezzo surfaces of degree d over an arbitraryperfect field is classical for d = 7, 8, 9 and new for d = 6. The same is the case for thedescription of their groups of automorphisms. Their classification and the description of theirautomorphism groups is much more difficult for d ≤ 5, as one can see already if the groundfield is the field of real numbers, and the classification is open over a general perfect field.Partial classifications exist over finite fields. Accordingly, we do not know their automorphismgroups in general.The objective of the thesis is to classify the smooth rational del Pezzo surfaces of degreed = 5 and d = 4 over an arbitrary perfect field and describe their automorphism groups.Due to the difficulty of the project, the case d = 4 will only be studied over the field ofreal numbers

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Sun, Chen-Cheng, and 孫承正. "Surface free energy of non-stick coatings deposited using closed field unbalanced magnetron sputter ion plating." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/96769520372925424088.

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博士
國立成功大學
材料科學及工程學系碩博士班
95
Semiconductor IC packaging molding dies require wear resistance, corrosion resistance and non-sticking (with a low surface free energy). The molding releasing capability and performance are directly associated with the surface free energy between the coating and product material. The serious sticking problem reduces productivity and reliability. Depositing TiN, TiMoS, ZrN, CrC, CrN, NiCr, NiCrN, CrTiAlN and CrNiTiAlN coatings using closed field unbalanced magnetron sputter ion plating, and characterizing their surface free energy are the main object in developing a non-stick coating system for semiconductor IC molding tools. The contact angle of water, diiodomethane and ethylene glycol on the coated surfaces were measured at temperature in 20 ℃ using a Dataphysics OCA-20 contact angle analyzer. The surface free energy of the coatings and their components (dispersion and polar) were calculated using the Owens-Wendt geometric mean approach. The surface roughness were investigated by atomic force microscopy (AFM). The adhesion force of these coatings were measured using direct tensile pull-off test apparatus. The experimental results showed that NiCrN, CrN and NiCrTiAlN coatings outperformed TiN, ZrN, NiCr, CiTiAlN, CrC and TiMoS coatings in terms of non-sticking, and thus have the potential as working layers for injection molding industrial equipment, especially in semiconductor IC packaging molding applications.

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Книги з теми "Non-Closed fields"

Hrushovski, Ehud, and François Loeser. Specializations and ACV2F. Princeton University Press, 2017. http://dx.doi.org/10.23943/princeton/9780691161686.003.0009.

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This chapter introduces the theory ACV²F of iterated places and describes some algebraic criteria for v- and g-continuity. It considers the theory ACV²F of triples (K₂,K₁,K₀) of fields with surjective, non-injective places rᵢⱼ : Kᵢ → Kⱼ for i > j, r₂₀ = r₁₀ ° r₂₁, such that K₂ is algebraically closed. The chapter shows that the family of g-open sets is definable in definable families. It also presents some applications of the continuity criteria and concludes by proving that for each definable set of definable functions V → Wsuperscript Number Sign the subset of those that are g-continuous is definable.

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North, Jill. Time in Thermodynamics. Edited by Craig Callender. Oxford University Press, 2011. http://dx.doi.org/10.1093/oxfordhb/9780199298204.003.0011.

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It is often claimed, or hoped, that some temporal asymmetries are explained by the thermodynamic asymmetry in time. Thermodynamics, the macroscopic physics of pressure, temperature, volume, and so on, describes many temporally asymmetric processes. Heat flows spontaneously from hot objects to cold objects (in closed systems), never the reverse. More generally, systems spontaneously move from non-equilibrium states to equilibrium states, never the reverse. Delving into the foundations of statistical mechanics, this chapter reviews the many open questions in that field as they relate to temporal asymmetry. Taking a stand on many of them, it tackles questions about the nature of probabilities, the role of boundary conditions, and even the nature and scope of statistical mechanics.

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Частини книг з теми "Non-Closed fields"

Blume, Mark. "McKay Correspondence over Non Algebraically Closed Fields." In Algebraic and Complex Geometry, 47–75. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-05404-9_3.

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Kuznetsov, Alexander, and Yuri Prokhorov. "Rationality of Mukai Varieties over Non-closed Fields." In Rationality of Varieties, 249–90. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-75421-1_10.

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Hassett, Brendan, and Yuri Tschinkel. "Rationality of Fano Threefolds of Degree 18 over Non-closed Fields." In Rationality of Varieties, 237–47. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-75421-1_9.

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Zaman, M., K. Kleineidam, L. Bakken, J. Berendt, C. Bracken, K. Butterbach-Bahl, Z. Cai, et al. "Methodology for Measuring Greenhouse Gas Emissions from Agricultural Soils Using Non-isotopic Techniques." In Measuring Emission of Agricultural Greenhouse Gases and Developing Mitigation Options using Nuclear and Related Techniques, 11–108. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-55396-8_2.

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AbstractSeveral approaches exist for measuring greenhouse gases (GHGs), mainly CO2, N2O, and CH4, from soil surfaces. The principle methods that are used to measure GHG from agricultural sites are chamber-based techniques. Both open and closed chamber techniques are in use; however, the majority of field applications use closed chambers. The advantages and disadvantages of different chamber techniques and the principal steps of operation are described. An important part of determining the quality of the flux measurements is the storage and the transportation of the gas samples from the field to the laboratory where the analyses are carried out. Traditionally, analyses of GHGs are carried out via gas chromatographs (GCs). In recent years, optical analysers are becoming increasingly available; these are user-friendly machines and they provide a cost-effective alternative to GCs. Another technique which is still under development, but provides a potentially superior method, is Raman spectroscopy. Not only the GHGs, but also N2, can potentially be analysed if the precision of these techniques is increased in future development. An important part of this chapter deals with the analyses of the gas concentrations, the calculation of fluxes, and the required safety measures. Since non-upland agricultural lands (i.e. flooded paddy soils) are steadily increasing, a section is devoted to the specificities of GHG measurements in these ecosystems. Specialised techniques are also required for GHG measurements in aquatic systems (i.e. rivers), which are often affected by the transfer of nutrients from agricultural fields and therefore are an important indirect source of emission of GHGs. A simple, robust, and more precise methodof ammonia (NH3) emission measurement is also described.

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Elduque, Alberto. "Gradings on Algebras over Algebraically Closed Fields." In Non-Associative and Non-Commutative Algebra and Operator Theory, 113–21. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-32902-4_7.

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Loke, Andrew. "Causation and Laws of Nature." In The Teleological and Kalam Cosmological Arguments Revisited, 37–70. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-94403-2_2.

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AbstractI define the key terms of the Causal Principle, namely ‘whatever’, ‘begins to exist’, and ‘cause’, and the related terms ‘time’, ‘eternal’, ‘event’, ‘change’, ‘perdurantism’, and ‘uncaused’. In particular, something has a beginning if it has a temporal extension, the extension is finite, and it has temporal edges/boundaries, that is, it does not have a static closed loop or a changeless/timeless phase that avoids an edge. This definition is compatible with both dynamic and static theories of time. While causal eliminativists and causal reductionists have claimed that causation has no basis in fundamental physics others have replied that fundamental physics does not provide a complete description of reality, and that it does not exclude causation and causal properties which operate at a more fundamental level as the ground of the regularities described by fundamental physics (Weaver, Fundamental Causation: Physics, Metaphysics, and the Deep Structure of the World. London: Routledge, 2019). Quantum physics has not shown that the Causal Principle is violated given that (1) quantum particles emerge from the quantum vacuum which is not non-being but something with vacuum fields, (2) radioactive disintegration of atomic nuclei exhibit statistical regularities that strongly indicate the existence of more fundamental ordered causes, and (3) many different interpretations of quantum physics exist, and some are perfectly deterministic.

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Steinbach, Ingo, and Hesham Salama. "Quantum Phase Field." In Lectures on Phase Field, 79–90. Cham: Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-21171-3_8.

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AbstractIn this chapter a new paradigm for the understanding of the physical world is developed based on phase-field type non-linear wave solutions. Two 1-dimensional wave fronts, right- and left-moving are combined to define the doubloon, the basic element of mass and space. The interface energy of a standard phase field defines the mass of elementary particles. The non-zero values of the phase field, the core of the doubloon, defines space in an introverted view. The sum constraint of the multi-phase-field model defines a doubloon network which is closed in itself. The model can be applied to investigate scale formation in the universe.

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Kumar, Ramesh, Shivam Raj, and S. K. Dhiman. "Experimental and Numerical Analysis of Ferrofluid in Partially Heated Closed Rectangular Microchannel Tube Under Non-uniform Magnetic Field." In Fluid Mechanics and Fluid Power, Volume 4, 577–90. Singapore: Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-99-7177-0_49.

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Elío, Javier, Marina Georgati, Henning S. Hansen, and Carsten Keßler. "Migration Studies with a Compositional Data Approach: A Case Study of Population Structure in the Capital Region of Denmark." In Computational Science and Its Applications – ICCSA 2022 Workshops, 576–93. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-10545-6_39.

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AbstractComputing percentages or proportions for removing the influence of population density has recently gained popularity, as it offers a deep insight into compositional variability. However, data are constrained to a constant sum and therefore are not independent observations, a fundamental limitation for applying standard multivariate statistical tools. Compositional Data (CoDa) techniques address the issue of standard statistical tools being insufficient for the analysis of closed data (i.e., spurious correlations, predictions outside the range, and sub-compositional incoherence) but they are not widely used in the field of population geography. Hence, in this article, we present a case study where we analyse at parish level the spatial distribution of Danes, Western migrants and non-Western migrants in the Capital region of Denmark. By applying CoDa techniques, we have been able to identify the spatial population segregation in the area and we have recognised patterns in the distribution of various demographic groups that can be used for interpreting housing prices variations. Our exercise is a basic example of the potentials of CoDa techniques which generate more robust and reliable results than standard statistical procedures in order to interpret the relations among various demographic groups. It can be further generalised to other population datasets with more complex structures.

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Curzel, Serena. "Modern High-Level Synthesis: Improving Productivity with a Multi-level Approach." In Special Topics in Information Technology, 15–25. Cham: Springer Nature Switzerland, 2024. http://dx.doi.org/10.1007/978-3-031-51500-2_2.

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AbstractHigh-Level Synthesis (HLS) tools simplify the design of hardware accelerators by automatically generating Verilog/VHDL code starting from a general-purpose software programming language. Because of the mismatch between the requirements of hardware descriptions and the characteristics of input languages, HLS tools still require hardware design knowledge and non-trivial design space exploration, which might be an obstacle for domain scientists seeking to accelerate applications written, for example, in Python-based programming frameworks. This research proposes a modern approach based on multi-level compiler technologies to bridge the gap between HLS and high-level frameworks, and to use domain-specific abstractions to solve domain-specific problems. The key enabling technology is the Multi-Level Intermediate Representation (MLIR), a framework that supports building reusable compiler infrastructure. The proposed approach uses MLIR to introduce new optimizations at appropriate levels of abstraction outside the HLS tool while still relying on years of HLS research in the low-level hardware generation steps; users and developers of HLS tools can thus increase their productivity, obtain accelerators with higher performance, and not be limited by the features of a specific (possibly closed-source) backend. The presented tools and techniques were designed, implemented, and tested to synthesize machine learning algorithms, but they are broadly applicable to any input specification written in a language that has a translation to MLIR. Generated accelerators can be deployed on Field Programmable Gate Arrays or Application-Specific Integrated Circuits, and they can reach high energy efficiency without any manual optimization of the code.

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Тези доповідей конференцій з теми "Non-Closed fields"

Su, Yi, Bin Zhang, Junqing Hou, Yifeng Chen, Jieyu Jiang, and Wei Li. "Numerical Simulation and Flame Characteristics Analysis of Non-Premixed Swirling Combustion." In ASME 2021 Heat Transfer Summer Conference collocated with the ASME 2021 15th International Conference on Energy Sustainability. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/ht2021-62482.

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Abstract Swirling flames are important in practical industrial combustors. The dynamic characteristics of swirling flames form complex velocity and temperature fields, which indicate combustion efficiency and influence pollutant emission. A reliable numerical simulation that can calculate the entire velocity and temperature fields is required to understand and investigate the underlying combustion mechanism. The governing equations of the methane swirling combustion process consist of the mass conservation, Navier-Stokes, and energy equations, all of which are solved by the SIMPLE algorithm based on finite volume method. This study performed a simulation using the realizable k-ε and non-premixed models in conjunction with the GRI Mech 3.0 mechanism. The characteristics of swirling combustion were analyzed on the bases of visualizations of temperature distribution, velocity distribution, and streamlines. In each cross section with varying heights from the nozzle, the high velocity and high temperature areas showed similar closed or semi-closed annular structures. In the central longitudinal section, the V-shaped high temperature and high velocity regions showed the swirling structure of the combustion flow field. The high temperature area did not coincide with the high velocity area but was located relatively downstream. The high velocity area was in the periphery of the high temperature area. Furthermore, the effects of swirl blade position on methane combustion characteristics were discussed. The validity of the numerical simulation results was verified by the simultaneous laser measurement of 3D temperature and velocity fields in the swirling flame.

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Chen, Chen, Su-xia Hou, Quan-hu Zhang, Xiang-hua Su та Wen-ming Zuo. "Research of γ-Ray 3D Scanning Detection and Analysis System". У 2018 26th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/icone26-81929.

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With the development of nuclear industry, nuclear facilities have accumulated a large amount of pending nuclear waste during operation. Usually, they are stored in a closed container, and their physical and chemical forms are complicated and unevenly distributed. γ-ray 3D scanning detection and analysis system using non-destructive analysis of γ-ray analysis method to achieve a closed container of radionuclide recognition, positioning, quantitative measurement and analysis. The system has broad application prospects in the fields of nuclear safety, nuclear material control and accounting, radioactive recyclables and non-destructive measurement of nuclear waste. γ-ray 3D scanning detection and analysis technology is a comprehensive high-tech integrated nuclear science, nuclear radiation detection, radiation imaging, image processing, mechanical design, automatic control, computer technology and other disciplines.

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Alhassani, A. A., M. Z. Baig, S. A. Elazab, C. Burgess, D. P. Caillon, O. A. Alvarado, and A. Al Bannay. "Water Management Strategy in UAE's Unconventional Fields: A Case Study of Closed Loop Operations and Novel Treatment Technologies." In ADIPEC. SPE, 2024. http://dx.doi.org/10.2118/221949-ms.

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Abstract As part of the UAE's commitment to Environmental Social Governance (ESG), unconventional exploration operations adhere to a strict zero-tolerance policy regarding spills. Consequently, closed-loop operations were instituted across all rigs and sites, ensuring no water is discharged into pits. This approach is supported by a thoroughly planned treatment and discharge strategy established before operations begin. This paper will delineate the water management strategy, focusing on the closed-loop system and innovative treatment technologies that facilitate H2S removal without infusing chemicals into the produced fluid. By preventing both over- and under-treatment, this method not only enhances operational efficiency but also reduces costs. A major challenge encountered was managing and treating high-temperature flowback water exceeding 200 degrees Fahrenheit. Additionally, the paper will explore the technical and operational experiences in establishing the water management process for Zipper frac operations, where over 800,000 barrels of water were pumped. It includes the sourcing, storage, and treatment protocols, alongside modifications to testing and treatment equipment designed to handle high-temperature, high-pressure flowback water. The use of real-time, non-chemical H2S treatment methods reduced testing time by 50%. Initiatives aiming for efficient and cost-effective water management solutions are being explored to facilitate the profitable development of unconventional gas and oil in the UAE. These initiatives strive to merge optimal performance and low-cost strategies with current regulations and environmental requirements to ensure sustainable operational security. The scope of the paper extends these closed-loop operations to metal extraction, applying circular economy principles to unconventional completion operations. While the development of unconventional oil and gas resources has transformative impacts on the UAE and global energy markets, concerns about water availability in desert regions remain. The UAE, however, benefits from significant oil and gas reserves as well as abundant water resources—both surface and subterranean—and advanced local water treatment technologies and services. Moreover, the basin's proximity to the sea and the stratigraphic setting of target unconventional reservoirs below known aquifers like Simsima and Um Radhuma provide notable advantages.

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Khalid, Ali, Qasim Ashraf, Khurram Luqman, Ayoub Hadj-Moussa, Agha Ghulam Nabi, Faizan Bari Khan, and Muhammad Azhar Khan. "Closed Loop Nitrified Foam MPD Delivers Unprecedented Drilling Performance in a Mature Sour Gas Field in Pakistan." In International Petroleum Technology Conference. IPTC, 2021. http://dx.doi.org/10.2523/iptc-21266-ms.

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Abstract As oil and gas reserves mature the world over, operators are looking towards advanced methods of increasing the ultimate recovery from their ageing fields. An energy deficient country of Pakistan relies heavily on oil and gas imports. The country was once self sustaining in at least natural gas needs. A major portion of this gas was produced from the Field-X which was discovered in the 1950’s. The primary reservoir in Field-X is the YZ-Limestone reservoir which bears sour gas. Due to extensive production from the YZ-Limestone formation, the reservoir pressure has depleted to a mere 2.0 PPG in equivalent mud weight, and it being a naturally fractured limestone formation presents numerous drilling challenges. The operator has evaluated a potential higher pressured formation in the deeper horizons of sui field but that requires drilling through approximately 650-690 meters of the YZ-Limestone formation. This feat when attempted conventionally is plagued with numerous problems like, total lost circulation, differential sticking, influxes due to the loss of a sufficient hydrostatic head, and stuck pipe following well control events. To mitigate these challenges the operator, need an effective method to drill through this depleted formation without pumping heavy LCM pills, and multiple cement plugs across the massive cavernous thief zones in the YZ-Limestone formation which could have been detrimental to the production of nearby wells. Moreover, such remedies with specialized LCM’s and acid soluble plugs would have resulted in excessive material cost and non-productive time, which in some instances extended to a period of more than a month. To address the aforementioned challenges in drilling the YZ-Limestone formation, a multiphase managed pressure drilling system was suggested to drill the formation with minimal non-productive time and cost. Multiphase hydraulics were performed to assess appropriate pumping parameters for a near-balanced condition across the YZ-Limestone formation. A closed loop MPD equipment system was designed to help maintain near-balanced conditions in pumping and static (non-circulating) periods. The designed equipment system would also ensure that the risk of H2S exposure to the atmosphere was eliminated. The application of a closed loop nitrified mpd system on a recently drilled well proved to be highly successful and reduced the drilling time to just 28 hours by not only eliminating fluid lost circulation but by also delivering an extremely high rate of penetration of 39.2 m/hr. The successful and exemplary application of nitrified MPD has opened up a new horizon for the development of deeper prospects in the Field-X and similar neighboring fields. The paper outlines the design and execution of the closed loop nitrified MPD system.

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Sotiropoulos, Fotis, Igor Mezić, and Donald R. Webster. "A Non-Intrusive Experimental Technique for Constructing Poincaré Maps in 3D Chaotically Advected Flows." In ASME 2001 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/imece2001/fed-24932.

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Abstract We propose and develop the theoretical framework for a new experimental technique for constructing Poincaré maps in three-dimensional flows exhibiting chaotic advection. The technique is non-intrusive and, thus, simple to implement. Planar laser-induced fluorescence (LIF) is employed to collect a sufficiently long sequence of instantaneous light intensity fields on the plane of section of the Poincaré map (defined by the laser sheet). The chains of unmixed (regular) islands in the flow are visualized by time-averaging the instantaneous images and plotting iso-contours of the resulting mean light intensity field. A rigorous theoretical justification for this technique is derived using concepts from ergodic theory. We demonstrate the capabilities of the method by applying it to visualize the rich Lagrangian dynamics within steady vortex breakdown bubbles in a closed cylinder with a rotating bottom. The experimental results are shown to be in excellent agreement with numerical simulations.

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Olutusin, D., N. AlMajed, J. Barki, M. Chong, and P. Ranjan. "Identifying Subsurface Characteristic or Attributes that enabled Produced Water Disposal and Increasing Production in a Mature Field Sabriyah North Kuwait: A case study." In SPE Water Lifecycle Management Conference and Exhibition. SPE, 2024. http://dx.doi.org/10.2118/218975-ms.

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Abstract Mature fields generally require water injection to either provide pressure support to sustain oil production and or arrest decline. The injected water produced along with oil as fluid requires separation for reinjection or disposal. Surface disposal requirements often creates increased environmental scrutiny and regulatory compliance obligations may pose significant operational and cost challenges that can limit efficiency and profitability. A cost and operationally efficient approach must include subsurface disposal. This project discusses an approach to identifying subsurface characteristic or attribute that allows for a cost effective approach to produced water disposal and enhancing oil production by 1-3% within a mature field. Identifying existing closed wells and formations with high capacity to handle the water disposal has a vital role in the overall field development by allowing currently closed highly water cut wells put back on production. Initial step was to nominate potential non-reservoir formation, if any, that is suitable for produced water disposal. Several closed wells penetrating these formations provide cost effectiveness without having to trigger new Capital expenditure. Detailed geological, seismic and cement bond evaluation of existing closed wells helped to narrow down and identify candidates for disposal opportunities. An Early Cretaceous (Aptian) Shuaiba formation with thickness ranging in 150-450ft across Sabriyah field selected as suitable. The formation, though non-hydrocarbon bearing in study area, is a highly dolomitized limestone with characteristic packestone and grainstone facies. The carbonate sedimentology highly fractured cavernous porosity with history of causing drilling operations challenges includes excessive losses, bad cement bonds among others. Suitable zones within candidate wells identified and perforated for Injectivity testing. A combination of high precision temperature and noise logs along with injection logging tools used to evaluate and establish Injectivity within the Shuaiba formation. Preliminary results confirmed that Shuaiba formation is a good candidate disposal formation that can handle surplus water production. Initial estimates indicated disposal intake capacity of up to 14400 bwpd at 1200-psi wellhead pressure. Disposal has continued for over twelve months within the pilot well and several more wells identified for repeat performance. The first successful operation to support produced water disposal within the Shuaiba formation in Sabriyah Field North Kuwait. Subsurface injection and disposal in matured Sabriyah field has contributed to overall water cycle handling and management strategy. Asset owner are now able to sustain and enhance production by putting back more closed or high water cut wells back on production with potential to increase total field production by up to 10% without incurring significant operating or capital expenditure.

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Uyiosa, Osazuwa B., Esharegharan Ovokerhoyi, Taro Onajite, Baranu Suka, Ibikunle Gbolade, and Obot Aniekan. "Driving Profitability in Brownfield Field Cluster Production Through Focused Back-To-Basics WRFM Optimization & Restoration: Habic Field Cluster Experience." In SPE Nigeria Annual International Conference and Exhibition. SPE, 2023. http://dx.doi.org/10.2118/217145-ms.

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Abstract Most brown fields have inherent issues ranging from, but not limited to increasing water production, reservoir pressure decline, increasing sand production and wells/facility integrity challenges due to Asset aging. For the Habic Assets, frequent incidents of insecurity and vandalization of facilities has added non-engineering challenges to the effective management of Assets. Well production uptime is highly impacted by this new challenge, and this has necessitated continuous optimization and innovation to ensure that the Asset remains profitable. This paper presents the simple and cost-effective approach used by the integrated Petroleum Engineering & Asset Production teams to deliver business promise for the Asset. The integrated team reviewed various strategies to harness the benefits of the age long "fix-the-basics" tools to arrest the dwindling fortunes of the Assets. Two key approaches were employed: firstly, surveillance data was incorporated in integrated production system models (IPSM) and using the Chan diagnostic tool, well operating envelopes were defined and used for optimization of producers. Based on the outcome of the reviews, the team proposed several production system optimizations with combined estimated gain of ca. 7800 bopd within allowable rate. Secondly, long closed-in well stock meant for temporary securing in line with standard well integrity recommended practice were flow tested using surveillance data gathered as a guide. The team prioritized strings in terms of historical closed-in tubing head pressure (CITHP), held risk assessments sessions and secured mitigations to perform the flow trial. This led to the identification of 7 conduits with combined potential of 4200 bopd. Both restoration and optimization efforts from integrated review of producing and closed-in well stock has added a combined potential of 6200 bopd with a further ca.5800 bopd expected once the outstanding optimization opportunities and open-up of 3 other closed-in wells are implemented and tested.

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Na, Sungsoo, and Liviu Librescu. "Modeling and Vibration Feedback Control of Rotating Tapered Beams Incorporating Adaptive Capabilities." In ASME 2000 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/imece2000-1253.

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Abstract This paper addresses the problem of the modeling and vibration control of tapered rotating blades modeled as thin-walled beams and incorporating adaptive capabilities. The blade model incorporates non-classical features such as anisotropy, transverse shear, secondary warping and includes the centrifugal and Coriolis force fields. For the non-adaptive system, a thorough validation and assessment of a number of nonclassical features including the taper characteristics is accomplished. The adaptive capabilities are provided by a system of piezoactuators bonded or embedded into the structure and spread over the entire span of the beam. Based on the converse piezoelectric effect, the piezoactuators produce a localized strain field in response to a voltage and consequently, a change of the dynamic response characteristics is induced. A combined feedback control law relating the piezoelectrically induced transversal bending moment at the beam tip with the kinematical response quantities appropriately selected is used and the beneficial effects upon the closed-loop dynamic characteristics of the blade are highlighted.

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Lee, Darrell R., Russell C. Cipolla, and Michael C. Liu. "Stress Intensity Factor Coefficients for Circumferential OD Surface Flaws in Cylinders for Appendix A of ASME Section XI." In ASME 2018 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/pvp2018-84381.

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Linear elastic fracture mechanics based flaw evaluation procedures in Section XI of the ASME Boiler and Pressure Vessel Code require calculation of the stress intensity factor (KI). The 2015 Edition of ASME Section XI [1] implemented a number of significant improvements in Article A-3000, including closed-form equations for calculating stress intensity factor influence coefficients (Gi) for circumferential flaws on the inside surface of cylinders. In the 2017 Edition [2], closed-form equations for axial flaws on the inside and outside surfaces of cylinders have been implemented. In this paper, closed-form equations are developed for circumferential cracks on the OD surface of cylinders, based on tabular data from API 579 (2007 Edition) [3]. The equations presented, represent a complete set of Ri/t, a/t, and a/ℓ ratios. The closed-form equations provide G0 and G1 coefficients while G2 through G4 are obtained using a weight function representation for the KI solutions for a surface crack. These equations permit the calculation of the Gi coefficients without the need to perform tabular interpolation. The equations are complete up to a fourth order polynomial representation of the applied stress. The fourth-order representation for stress will allow for more accurate fitting of highly non-linear stress distributions, such as those depicting high thermal gradients and weld residual stress fields.

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Renn, Jyh-Chyang, and Chin-Yi Cheng. "A Novel Pneumatic Non-Contact Suction Pad With Embedded Air Bearings." In ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-40032.

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In this paper, a novel suction pad based on CFD simulation and vortex levitation principle is proposed. To assure the absolute non-contact between the suction pad and the work-piece, four symmetrical air bearings are introduced and integrated into the design of the suction pad. In addition, the closed-loop gap control is applied to the operation of the suction pad, which avoids successfully the possible initial impact and maintains the desired gap between the suction pad and the work-piece. The vortex inside the suction pad serves to levitate the work-piece and the air bearings, on the contrary, try to push the work-piece away if the work-piece comes too close to the suction pad. Therefore, a proper function switching between the vortex and the air bearings is necessary. In this paper, a 5/3 pneumatic proportional directional control valve is utilized to switch these functions mentioned above. In the future, such a suction pad may find some potential application fields, like the pick-up and transportation devices for TFT-LCD, solar energy panels, etc.

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