Literatura académica sobre el tema "Partial suitable solutions"
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Artículos de revistas sobre el tema "Partial suitable solutions"
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Yan, Xiaodong. "Partial Regularity of Suitable Weak Solutions of Complex Ginzburg Landau Equations". Communications in Partial Differential Equations 24, n.º 11-12 (enero de 1999): 390–93. http://dx.doi.org/10.1080/03605309908821501.
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He, Cheng y Zhouping Xin. "Partial regularity of suitable weak solutions to the incompressible magnetohydrodynamic equations". Journal of Functional Analysis 227, n.º 1 (octubre de 2005): 113–52. http://dx.doi.org/10.1016/j.jfa.2005.06.009.
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Ren, Wei, Yanqing Wang y Gang Wu. "Partial regularity of suitable weak solutions to the multi-dimensional generalized magnetohydrodynamics equations". Communications in Contemporary Mathematics 18, n.º 06 (14 de septiembre de 2016): 1650018. http://dx.doi.org/10.1142/s0219199716500188.
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In this paper, we are concerned with the partial regularity of the suitable weak solutions to the fractional MHD equations in [Formula: see text] for [Formula: see text]. In comparison with the work of the 3D fractional Navier–Stokes equations obtained by Tang and Yu in [Partial regularity of suitable weak solutions to the fractional Navier–Stokes equations, Comm. Math. Phys. 334 (2015) 1455–1482], our results include their endpoint case [Formula: see text] and the external force belongs to a more general parabolic Morrey space. Moreover, we prove some interior regularity criteria just via the scaled mixed norm of the velocity for the suitable weak solutions to the fractional MHD equations.
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Tang, Lan y Yong Yu. "Partial Regularity of Suitable Weak Solutions to the Fractional Navier–Stokes Equations". Communications in Mathematical Physics 334, n.º 3 (19 de septiembre de 2014): 1455–82. http://dx.doi.org/10.1007/s00220-014-2149-z.
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Wang, Xiaoming, Shehbaz Ahmad Javed, Abdul Majeed, Mohsin Kamran y Muhammad Abbas. "Investigation of Exact Solutions of Nonlinear Evolution Equations Using Unified Method". Mathematics 10, n.º 16 (19 de agosto de 2022): 2996. http://dx.doi.org/10.3390/math10162996.
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In this article, an analytical technique based on unified method is applied to investigate the exact solutions of non-linear homogeneous evolution partial differential equations. These partial differential equations are reduced to ordinary differential equations using different traveling wave transformations, and exact solutions in rational and polynomial forms are obtained. The obtained solutions are presented in the form of 2D and 3D graphics to study the behavior of the analytical solution by setting out the values of suitable parameters. The acquired results reveal that the unified method is a suitable approach for handling non-linear homogeneous evolution equations.
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Zhang, Huan, Yin Zhou y Yuhua Long. "Results on multiple nontrivial solutions to partial difference equations". AIMS Mathematics 8, n.º 3 (2022): 5413–31. http://dx.doi.org/10.3934/math.2023272.
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<abstract><p>In this paper, we consider the existence and multiplicity of nontrivial solutions to second order partial difference equation with Dirichlet boundary conditions by Morse theory. Given suitable conditions, we establish multiple results that the problem admits at least two nontrivial solutions. Moreover, we provide five examples to illustrate applications of our theorems.</p></abstract>
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Jiu, Quansen y Yanqing Wang. "Remarks on partial regularity for suitable weak solutions of the incompressible magnetohydrodynamic equations". Journal of Mathematical Analysis and Applications 409, n.º 2 (enero de 2014): 1052–65. http://dx.doi.org/10.1016/j.jmaa.2013.07.052.
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Matsuzawa, Tadato. "Partial regularity and applications". Nagoya Mathematical Journal 103 (octubre de 1986): 133–43. http://dx.doi.org/10.1017/s0027763000000623.
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The problem to determine the Gevrey index of solutions of a given hypoelliptic partial differential equation seems to be not yet well investigated. In this paper, we shall show the Gevrey indices of solutions of the equations of Grushin type, [6], are determined by a rather simple application of a straightforward extension of the results given in [7], [8] and [13]. For simplicity to construct left parametrices in the operator valued sense, we shall consider the equations under the stronger condition than that of [6] (cf. Condition 1 of Section 3). Typical examples of Grushin type are given by which will be discussed in Section 4. We remark that our approach may be compared with the one to a similar problem discussed in [17] by using suitable L2-estimates constructed in [16].
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Yang, Jiaqi. "Partially regular weak solutions to the fractional Navier–Stokes equations with the critical dissipation". Journal of Mathematical Physics 63, n.º 11 (1 de noviembre de 2022): 111501. http://dx.doi.org/10.1063/5.0088047.
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We show that there exist partially regular weak solutions of Navier–Stokes equations with fractional dissipation [Formula: see text] in the critical case of [Formula: see text], which satisfy certain local energy inequalities and whose singular sets have a locally finite two-dimensional parabolic Hausdorff measure. Actually, this problem had been studied by Chen and Wei [Discrete Contin. Dyn. Syst. 36(10), 5309–5322 (2016)]; in this paper, they established the partial regularity of suitable weak solutions for [Formula: see text]. A point is that they admitted the existence of suitable weak solutions but did not give the proof. It should be noted that, when [Formula: see text], the existence of suitable weak solutions is not trivial due to the possible lack of compactness. To overcome this difficulty, we shall use a parabolic concentration-compactness theorem introduced by Wu [Arch. Ration. Mech. Anal. 239(3), 1771–1808 (2021)]. For the partial regularity theory, we will apply the idea of Chen and Wei.
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Pla, Francisco y Henar Herrero. "Reduced Basis Method Applied to Eigenvalue Problems from Convection". International Journal of Bifurcation and Chaos 29, n.º 03 (marzo de 2019): 1950028. http://dx.doi.org/10.1142/s0218127419500287.
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The reduced basis method is a suitable technique for finding numerical solutions to partial differential equations that must be obtained for many values of parameters. This method is suitable when researching bifurcations and instabilities of stationary solutions for partial differential equations. It is necessary to solve numerically the partial differential equations along with the corresponding eigenvalue problems of the linear stability analysis of stationary solutions for a large number of bifurcation parameter values. In this paper, the reduced basis method has been used to solve eigenvalue problems derived from the linear stability analysis of stationary solutions in a two-dimensional Rayleigh–Bénard convection problem. The bifurcation parameter is the Rayleigh number, which measures buoyancy. The reduced basis considered belongs to the eigenfunction spaces derived from the eigenvalue problems for different types of solutions in the bifurcation diagram depending on the Rayleigh number. The eigenvalue with the largest real part and its corresponding eigenfunction are easily calculated and the bifurcation points are correctly captured. The resulting matrices are small, which enables a drastic reduction in the computational cost of solving the eigenvalue problems.
Tesis sobre el tema "Partial suitable solutions"
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Llerena, Montenegro Henry David. "Sur l'interdépendance des variables dans l'étude de quelques équations de la mécanique des fluides". Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASM048.
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Cette thèse est consacrée à l'étude de la relation entre les variables dans les équations des fluides micro-polaires. Ce système, basé sur les équations de Navier-Stokes, consiste en un couplage de deux variables: le champ de vitesse vec{u} et le champ de micro-rotation vec{w}. Notre objectif est de mieux comprendre comment l'information concernant une variable influence le comportement de l'autre. À cette fin, nous avons divisé cette thèse en quatre chapitres, où nous étudierons les propriétés de régularité locale des solutions faibles de type Leray, puis nous nous concentrerons sur la régularité et l'unicité des solutions faibles dans le cas stationnaire. Le premier chapitre présente une rapide déduction physique des équations micro-polaires, suivie de la construction des solutions faibles de type Leray. Dans le chapitre 2, nous commençons par prouver un gain d'intégrabilité pour les deux variables vec{u} et vec{w} lorsque la vitesse appartient à certains espaces de Morrey. Ce résultat souligne un effet de domination de la vitesse. Nous montrons ensuite que cet effet peut également être observé dans le cadre de la théorie de Caffarelli-Kohn-Nirenberg, i.e., sous une hypothèse de petitesse supplémentaire uniquement sur le gradient de la vitesse, nous pouvons démontrer que la solution devient Hölder continue. Pour cela, nous introduisons la notion de solution partiellement adaptée, qui est fondamentale dans ce travail et représente l'une des principales nouveautés. Dans la dernière section de ce chapitre, nous obtenons des résultats similaires dans le contexte du critère de Serrin. Dans le chapitre 3, nous nous concentrons sur le comportement de la norme L^3 de la vitesse vec{u} autour des possibles points où la régularité peut être perdue. Plus précisément, nous établissons un critère d'explosion pour la norme L^3 de la vitesse et améliorons ce résultat en présentant un phénomène de concentration. Nous vérifions également que le cas limite L^infty_t L^3_x du critère de Serrin reste valable pour les équations des fluides micro-polaires. Enfin, le problème de l'existence et de l'unicité des équations stationnaires des fluides micro-polaires est abordé dans le chapitre 4. En effet, nous prouvons l'existence de solutions faibles (vec{u}, vec{w}) dans l'espace d'énergie naturel dot{H}^1(mathbb{R}^3) imes H^1(mathbb{R}^3). De plus, en utilisant la relation entre les variables, nous déduisons que ces solutions sont régulières. Il convient de noter que la solution triviale peut ne pas être unique, et pour surmonter cette difficulté, nous développons un théorème de type Liouville. Ainsi, nous démontrons qu'en imposant une décroissance plus forte à l'infini uniquement sur vec{u}, nous pouvons en déduire l'unicité de la solution triviale (vec{u},vec{w})=(0,0)This thesis is devoted to the study of the relationship between the variables in the micropolar fluids equations. This system, which is based on the Navier-Stokes equations, consists in a coupling of two variables: the velocity field vec{u} and the microrotation field vec{w}. Our aim is to provide a better understanding of how information about one variable influences the behavior of the other. To this end, we have divided this thesis into four chapters, where we will study the local regularity properties of Leray-type weak solutions, and later we will focus on the regularity and uniqueness of weak solutions for the stationary case. The first chapter presents a brief physical derivation of the micropolar equations followed by the construction of the Leray-type weak solutions. In Chapter 2, we begin by proving a gain of integrability for both variables vec{u} and vec{w} whenever the velocity belongs to certain Morrey spaces. This result highlights an effect of domination by the velocity. We then show that this effect can also be observed within the framework of the Caffarelli-Kohn-Nirenberg theory, i.e., under an additional smallness hypothesis only on the gradient of the velocity, we can demonstrate that the solution becomes Hölder continuous. For this, we introduce the notion of a partial suitable solution, which is fundamental in this work and represents one of the main novelties. In the last section of this chapter, we derive similar results in the context of the Serrin criterion. In Chapter 3, we focus on the behavior of the L^3-norm of the velocity vec{u} near possible points where regularity may get lost. More precisely, we establish a blow-up criterion for the L^3 norm of the velocity and we improve this result by presenting a concentration phenomenon. We also verify that the limit point L^infty_t L^3_x of the Serrin criterion remains valid for the micropolar fluids equations. Finally, the problem of existence and uniqueness for the stationary micropolar fluids equations is addressed in Chapter 4. Indeed, we prove the existence of weak solutions (vec{u}, vec{w}) in the natural energy space dot{H}^1(mathbb{R}^3) imes H^1(mathbb{R}^3). Moreover, by using the relationship between the variables, we deduce that these solutions are regular. It is worth noting that the trivial solution may not be unique, and to overcome this difficulty, we develop a Liouville-type theorem. Hence, we demonstrate that by imposing stronger decay at infinity only on vec{u}, we can infer the uniqueness of the trivial solution (vec{u},vec{w})=(0,0)
Libros sobre el tema "Partial suitable solutions"
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Grewal, J. S. The Akali–Congress Compromise. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780199467099.003.0021.
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Authorized by a convention of all Sikh parties, Master Tara Singh, with four other Sikh leaders, met Jawaharlal Nehru on 24 October 1955. Maulana Azad and G.B. Pant were also present. The talks were ‘friendly but rather vague’. On 8 February 1956, a plan, generally known as the Regional Formula, was discussed by the Sikh leaders. In his address to the All-India Akali Conference on 11 February, Master Tara Singh dwelt on Punjabi Suba as the real solution for the Punjab problem. But the Akali Dal accepted the Regional Formula in March 1956. Furthermore, the Akali Dal Working Committee resolved in September 1956 to implement the Formula. The constitution of the Akali Dal was suitably amended and the Akali legislators joined the Congress party.
Capítulos de libros sobre el tema "Partial suitable solutions"
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Wolf, JÖrg. "A New Criterion for Partial Regularity of Suitable Weak Solutions to the Navier-Stokes Equations". En Advances in Mathematical Fluid Mechanics, 613–30. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-04068-9_34.
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Seifert, Christian, Sascha Trostorff y Marcus Waurick. "Initial Value Problems and Extrapolation Spaces". En Evolutionary Equations, 131–48. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-89397-2_9.
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AbstractUp until now we have dealt with evolutionary equations of the form $$\displaystyle \big (\overline {\partial _{t,\nu }M(\partial _{t,\nu })+A}\big )U=F $$ ( ∂ t , ν M ( ∂ t , ν ) + A ¯ ) U = F for some given $$F\in L_{2,\nu }(\mathbb {R};H)$$ F ∈ L 2 , ν ( ℝ ; H ) for some Hilbert space H, a skew-selfadjoint operator A in H and a material law M defined on a suitable half-plane satisfying an appropriate positive definiteness condition with $$\nu \in \mathbb {R}$$ ν ∈ ℝ chosen suitably large. Under these conditions, we established that the solution operator, "Equation missing", is eventually independent of ν and causal; that is, if F = 0 on $$\left (-\infty ,a\right ]$$ − ∞ , a for some $$a\in \mathbb {R}$$ a ∈ ℝ , then so too is U.
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Neele, Thomas, Antti Valmari y Tim A. C. Willemse. "The Inconsistent Labelling Problem of Stutter-Preserving Partial-Order Reduction". En Lecture Notes in Computer Science, 482–501. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-45231-5_25.
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AbstractIn model checking, partial-order reduction (POR) is an effective technique to reduce the size of the state space. Stubborn sets are an established variant of POR and have seen many applications over the past 31 years. One of the early works on stubborn sets shows that a combination of several conditions on the reduction is sufficient to preserve stutter-trace equivalence, making stubborn sets suitable for model checking of linear-time properties. In this paper, we identify a flaw in the reasoning and show with a counter-example that stutter-trace equivalence is not necessarily preserved. We propose a solution together with an updated correctness proof. Furthermore, we analyse in which formalisms this problem may occur. The impact on practical implementations is limited, since they all compute a correct approximation of the theory.
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Seifert, Christian, Sascha Trostorff y Marcus Waurick. "Non-Autonomous Evolutionary Equations". En Evolutionary Equations, 259–73. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-89397-2_16.
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AbstractPreviously, we focussed on evolutionary equations of the form $$\displaystyle \left (\overline {\partial _{t,\nu }M(\partial _{t,\nu })+A}\right )U=F. $$ ∂ t , ν M ( ∂ t , ν ) + A ¯ U = F . In this chapter, where we turn back to well-posedness issues, we replace the material law operator M(∂t,ν), which is invariant under translations in time, by an operator of the form $$\displaystyle \mathcal {M}+\partial _{t,\nu }^{-1}\mathcal {N}, $$ ℳ + ∂ t , ν − 1 N , where both $$\mathcal {M}$$ ℳ and $$\mathcal {N}$$ N are bounded linear operators in $$L_{2,\nu }(\mathbb {R};H)$$ L 2 , ν ( ℝ ; H ) . Thus, it is the aim in the following to provide criteria on $$\mathcal {M}$$ ℳ and $$\mathcal {N}$$ N under which the operator $$\displaystyle \partial _{t,\nu }\mathcal {M}+\mathcal {N}+A $$ ∂ t , ν ℳ + N + A is closable with continuous invertible closure in $$L_{2,\nu }(\mathbb {R};H)$$ L 2 , ν ( ℝ ; H ) . In passing, we shall also replace the skew-selfadjointness of A by a suitable real part condition. Under additional conditions on $$\mathcal {M}$$ ℳ and $$\mathcal {N}$$ N , we will also see that the solution operator is causal. Finally, we will put the autonomous version of Picard’s theorem into perspective of the non-autonomous variant developed here.
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Seifert, Christian, Sascha Trostorff y Marcus Waurick. "Examples of Evolutionary Equations". En Evolutionary Equations, 103–17. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-89397-2_7.
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AbstractThis chapter is devoted to a small tour through a variety of evolutionary equations. More precisely, we shall look into the equations of poro-elastic media, (time-)fractional elasticity, thermodynamic media with delay as well as visco-elastic media. The discussion of these examples will be similar to that of the examples in the previous chapter in the sense that we shall present the equations first, reformulate them suitably and then apply the solution theory to them. The study of visco-elastic media within the framework of partial integro-differential equations will be carried out in the exercises section.
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Xu, Liu-Jun y Ji-Ping Huang. "Theory for Invisible Thermal Sensors: Optimization Scheme". En Transformation Thermotics and Extended Theories, 163–75. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-5908-0_12.
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AbstractMetamaterial-based devices have been extensively explored for their intriguing functions, such as cloaking, concentrating, rotating, and sensing. However, they are usually achieved by employing metamaterials with extreme parameters, critically restricting engineering preparation. In this chapter, we propose an optimization model with particle swarm algorithms to simplify parametric designs to realize bilayer thermal sensors composed of bulk isotropic materials (circular structure). For this purpose, the fitness function is defined to evaluate the difference between the actual and expected temperatures. By choosing suitable materials for different regions and treating the sensor, inner shell, and outer shell radii as design variables, we finally minimize the fitness function via particle swarm optimization. The designed scheme is easy to implement in applications and shows excellent performances in detective accuracy and thermal invisibility, which are confirmed by finite-element simulations and laboratory experiments. The optimization model can also be flexibly extended to a square case. This method can calculate numerical solutions for difficult analytical theories (circular structure) and optimal solutions for problems without analytical theories (such as square structure), providing new inspiration for simplifying the design of metamaterials in various communities.
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Limone, Pierpaolo y Giusi Antonia Toto. "The Motivation of Distance Learning in Universities Since Covid- 19 Outbreak". En Psychology, Learning, Technology, 25–40. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-15845-2_2.
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AbstractAround midmonth March 2020, The World Health Organization acknowledged the COVID outbreak as a “public health emergency of international concern.” Worldwide, various heads of state-imposed mandatory lockdowns to curb and ease the spread of the disease. With such restrictions in hand, the education sector was among the many which felt the pinch brought about by the restriction measures imposed. To try and flatten the curve and minimize the spreading of the virus from one person to another, there was a need for reduced physical contact among people. According to Shahzad et al. (2020), public gatherings such as parties, religious services, social amenities, political gatherings, and physical learning for both universities and lower levels stopped since health comes first before anything else. With that in hand, the world had to look for suitable solutions to cope with the pandemic since the virus was not ending time soon; as a result, the globe adapted ‘the new normal of life. In response, education facilities had to embark on e-learning since life had to continue, which is great gratitude to technology. However, it brought about various issues that we will try and highlight since a change in anything is always accompanied by multiple challenges.
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Temple, Lucy y Gregor Eibl. "Evaluating Digital Government Projects: Emphasizing Process and Relevance Through Transdisciplinary Research". En From Electronic to Mobile Government, 125–43. Cham: Springer Nature Switzerland, 2024. http://dx.doi.org/10.1007/978-3-031-64471-9_8.
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AbstractGovernment organizations worldwide focus on digital solutions to improve public services and enhance citizen experience. These initiatives continue to receive significant resource allocation. There exists the need for a thorough evaluation to ensure that these projects deliver the intended benefits and address citizen needs. Currently, the absence of a single suitable evaluation method poses a challenge. The complexity of these projects demands a dynamic evaluation environment to understand societal impact and relevance. Relevance implies assessing to what extent a project aligns with the stakeholders’ goals, needs, and desires, mainly government organizations and citizens or businesses. This chapter explores the importance of relevance in evaluating such projects and highlights the reasons for adopting a transdisciplinary research approach. Unlike traditional disciplinary-focused approaches, transdisciplinary research focuses on real-world context and interdisciplinarity, goes beyond just science, and promotes interaction and integration among involved parties to produce high relevance. By focusing on project outcomes and processes, this research aims to propose relevant metrics for evaluating digital government projects and their relevance in a real-world context. To do so, a series of European research and development projects focusing on digital government will be analyzed using the proposed transdisciplinary evaluation framework to understand if outcomes and processes promote project relevance. This research will help enhance current evaluation approaches for digital government projects. The findings of this study will contribute to the widening of evaluation frameworks for digital government initiatives.
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Law, D. W., C. Gunasekara y S. Setunge. "Use of Brown Coal Ash as a Replacement of Cement in Concrete Masonry Bricks". En Lecture Notes in Civil Engineering, 23–25. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-3330-3_4.
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AbstractPortland cement production is not regarded as environmentally friendly, because of its associated high carbon emissions, which are responsible for 5% of global emissions. An alternative is to substitute fly ash for Portland cement. Australia has an abundance of brown coal fly ash, as it is the main source of primary energy in the State of Victoria. Currently, the majority of this material is stored in landfills and currently there is no commercial use for it in the cement industry because brown coal fly ash cannot be used as a direct replacement material for Portland cement due to the high sulfur and calcium content and low aluminosilicate content. However, the potential exists to use brown coal fly ash as a geopolymeric material, but there remains a significant amount of research needed to be conducted. One possible application is the production of geopolymer concrete bricks. A research project was undertaken to investigate the use of brown coal fly ash from Latrobe Valley power stations in the manufacture of geopolymer masonry bricks. The research developed a detailed understanding of the fundamental chemistry behind the activation of the brown coal fly ash and the reaction mechanisms involved to enable the development of brown coal fly ash geopolymer concrete bricks. The research identified suitable manufacturing techniques to investigate relationships between compressive strength and processing parameters and to understand the reaction kinetics and microstructural developments. The first phase of the research determined the physical, chemical, and mineralogical properties of the Loy Yang and Yallourn fly ash samples to produce a 100% fly ash-based geopolymer mortar. Optimization of the Loy Yang and Yallourn geopolymer mortars was conducted to identify the chemical properties that were influential in the production of satisfactory geopolymer strength. The Loy Yang mortars were able to produce characteristic compressive strengths acceptable in load-bearing bricks (15 MPa), whereas the Yallourn mortars produced characteristic compressive strengths only acceptable as non-load-bearing bricks (5 MPa). The second phase of the research transposed the optimal geopolymer mortar mix designs into optimal geopolymer concrete mix designs while merging the mix design with the optimal Adbri Masonry (commercial partner) concrete brick mix design. The reference mix designs allowed for optimization of both the Loy Yang and Yallourn geopolymer concrete mix designs, with the Loy Yang mix requiring increased water content because the original mix design was deemed to be too dry. The key factors that influenced the compressive strength of the geopolymer mortars and concrete were identified. The amorphous content was considered a vital aspect during the initial reaction process of the fly ash geopolymers. The amount of unburnt carbon content contained in the fly ash can hinder the reactive process, and ultimately, the compressive strength because unburnt carbon can absorb the activating solution, thus reducing the particle to liquid interaction ratio in conjunction with lowering workability. Also, fly ash with a higher surface area showed lower flowability than fly ash with a smaller surface area. It was identified that higher quantity of fly ash particles <45 microns increased reactivity whereas primarily angular-shaped fly ash suffered from reduced workability. The optimal range of workability lay between the 110–150 mm slump, which corresponded with higher strength displayed for each respective precursor fly ash. Higher quantities of aluminum incorporated into the silicate matrix during the reaction process led to improved compressive strengths, illustrated by the formation of reactive aluminosilicate bonds in the range of 800–1000 cm–1 after geopolymerization, which is evidence of a high degree of reaction. In addition, a more negative fly ash zeta potential of the ash was identified as improving the initial deprotonation and overall reactivity of the geopolymer, whereas a less negative zeta potential of the mortar led to increased agglomeration and improved gel development. Following geopolymerization, increases in the quantity of quartz and decreases in moganite correlated with improved compressive strength of the geopolymers. Overall, Loy Yang geopolymers performed better, primarily due to the higher aluminosilicate content than its Yallourn counterpart. The final step was to transition the optimal geopolymer concrete mix designs to producing commercially acceptable bricks. The results showed that the structural integrity of the specimens was reduced in larger batches, indicating that reactivity was reduced, as was compressive strength. It was identified that there was a relationship between heat transfer, curing regimen and structural integrity in a large-volume geopolymer brick application. Geopolymer bricks were successfully produced from the Loy Yang fly ash, which achieved 15 MPa, suitable for application as a structural brick. Further research is required to understand the relationship between the properties of the fly ash, mixing parameters, curing procedures and the overall process of brown coal geopolymer concrete brick application. In particular, optimizing the production process with regard to reducing the curing temperature to ≤80 °C from the current 120 °C and the use of a one-part solid activator to replace the current liquid activator combination of sodium hydroxide and sodium silicate.
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Lockner, Yannik, Paul Buske, Maximilian Rudack, Zahra Kheirandish, Moritz Kröger, Stoyan Stoyanov, Seyed Ruhollah Dokhanchi et al. "Improving Manufacturing Efficiency for Discontinuous Processes by Methodological Cross-Domain Knowledge Transfer". En Internet of Production, 1–33. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-030-98062-7_8-1.
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AbstractDiscontinuous processes face common tasks when implementing modeling and optimization techniques for process optimization. While domain data may be unequal, knowledge about approaches for each step toward the solution, e.g., data gathering, model reduction, and model optimization, may be useful across different processes. A joint development of methodologies for machine learning methods, among other things, ultimately supports fast advances in cross-domain production technologies. In this work, an overview of common maturation stages of data-intensive modeling approaches for production efficiency enhancement is given. The stages are analyzed and communal challenges are elaborated. The used approaches include both physically motivated surrogate modeling as well as the advanced use of machine learning technologies. Apt research is depicted for each stage based on demonstrator work for diverse production technologies, among them high-pressure die casting, surface engineering, plastics injection molding, open-die forging, and automated tape placement. Finally, a holistic and general framework is illustrated covering the main concepts regarding the transfer of mature models into production environments on the example of laser technologies.Increasing customer requirements regarding process stability, transparency and product quality as well as desired high production efficiency in diverse manufacturing processes pose high demands on production technologies. The further development of digital support systems for manufacturing technologies can contribute to meet these demands in various production settings. Especially for discontinuous production, such as injection molding and laser cutting, the joint research for different technologies helps to identify common challenges, ranging from problem identification to knowledge perpetuation after successfully installing digital tools. Workstream CRD-B2.II “Discontinuous Production” confronts this research task by use case-based joint development of transferable methods. Based on the joint definition of a standard pipeline to solve problems with digital support, various stages of this pipeline, such as data generation and collection, model training, optimization, and the development and deployment of assistance systems are actively being researched. Regarding data generation, e.g., for the high-pressure die-casting process, data acquisition and extraction approaches for machines and production lines using OPC UA are investigated to get detailed process insights. For diverse discontinuous processes and use cases, relevant production data is not directly available in sufficient quality and needs to be preprocessed. For vision systems, ptychographic methods may improve recorded data by enhancing the picture sharpness to enable the usage of inline or low-cost equipment to detect small defects. Further down the pipeline, several research activities concern the domain-specific model training and optimization tasks. Within the realm of surface technologies, machine learning is applied to predict process behavior, e.g., by predicting the particle properties in plasma spraying process or plasma intensities in the physical vapor deposition process. The injection molding process can also be modeled by data-based approaches. The modeling efficiency based on the used amount of data can furthermore be effectively reduced by using transfer learning to transfer knowledge stored in artificial neural networks from one process to the next. Successful modeling approaches can then be transferred prototypically into production. On the examples of vision-based defect classification in the tape-laying process and a process optimization assistance system in open-die forging, the realization of prototypical support systems is demonstrated. Once mature, research results and consequent digital services must be made available for integrated usage in specific production settings using relevant architecture. By the example of a microservice-based infrastructure for laser technology, a suitable and flexible implementation of a service framework is realized. The connectivity to production assets is guaranteed by state-of-the-art communication protocols. This chapter illustrates the state of research for use-case-driven development of joint approaches.
Actas de conferencias sobre el tema "Partial suitable solutions"
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Zhao, Jinggen y Chengjian He. "Real-Time Simulation of Coaxial Rotor Configurations with Combined Finite State Dynamic Wake and VPM". En Vertical Flight Society 70th Annual Forum & Technology Display, 1–12. The Vertical Flight Society, 2014. http://dx.doi.org/10.4050/f-0070-2014-9567.
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This paper describes a first-principle based finite state dynamic rotor wake model that addresses the complex aerodynamic interference inherent to coaxial rotor configurations in support of advanced vertical lift aircraft simulation, design, and analysis. The high fidelity rotor dynamic wake solution combines an enhanced real-time finite state dynamic wake model (DYW) with a first-principle based viscous Vortex Particle Method (VPM). The finite state dynamic wake model provides a state-space real-time modeling capability for advanced rotorcraft configurations and VPM provides a first-principle based solution for the complex rotor wake problem without using ad-hoc parameters. To account for the mutual aerodynamic interference between multiple rotors, the finite state dynamic wake model was enhanced with several essential modeling parameters to empirically account for important physical phenomena. These modeling parameters were determined based on high fidelity VPM simulations. The developed methodology provides a first-principle based real-time finite state dynamic wake model suitable for coaxial rotor configurations. To validate the developed model, simulation results for the rotor performance, the rotor wake dynamics, and the flow field of different coaxial rotor configurations in both hover and forward flight conditions were compared with available measured data. The simulation results demonstrate good correlation with the measurements for all the cases evaluated.
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Wagner, Marcus M., Peter M. Pinsky y Manish Malhotra. "A Multiple-Frequency Partial-Field Method for Exterior Acoustics Based on Padé via Lanczos Approximants". En ASME 2001 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/imece2001/nca-23524.
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Abstract A solution methodology is introduced for the efficient computation of the acoustic field over restricted domains and for a frequency window. Typically, such partial field solutions include, for example, surfaces enclosing the radiating structure or even single points in the computational domain. The multiple-frequency partial-field (MFPF) method starts out by reformulating the finite element matrix system into a suitable shifted form. The DtN map is used as a radiation boundary condition and is interpreted as a low rank update of the matrix problem. The shifted standard form is then approximated by a rational matrix-valued Padé approximant and solved simultaneously over a frequency range. To obtain the Padé approximation, a banded unsymmetric Lanczos process is applied on the standard shifted form exploiting the matrix Padé-via-Lanczos connection. Numerical examples show the feasibility of the outlined procedure.
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Lu, Xiancheng y Chuen-Sen Lin. "A Proposed Method to Group the Solutions From Dimensional Synthesis: Planar Triads for Six Precision Position". En ASME 1992 Design Technical Conferences. American Society of Mechanical Engineers, 1992. http://dx.doi.org/10.1115/detc1992-0332.
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Abstract In this paper, a method has been proposed to group into six sets the infinite number of solutions from dimensional synthesis of planar triads for six precision positions. The proposed method reveals the relationships between the different configurations of the compatibility linkage and the sets of numerical solutions from dimensional synthesis. By checking the determinant signs and the contunities of values of the sub-Jacobian matrices and their derivatives with respect to the independent angular displacement for all constraint sets in the compatibility linkage, it enables the computer to identify and group the synthesized solutions. Numerical examples have been given to verify the applicability of this method. Six sets of the partial triad Burmester curves have been plotted based on grouped solutions. Suitable solutions can be easily found from the partial triad Burmester curves and utilized for the prescribed design task. This method provides a useful tool to group the dimensional synthesis solutions and enhances the computer automation in the design of linkage mechanisms.
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Dzbor, Martin y Zdenek Zdrahal. "Towards Logical Framework for Sequential Design". En ASME 2001 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/detc2001/dtm-21710.
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Abstract Engineering design is usually seen as a knowledge-intensive process that driven by certain objectives eventually delivers an artefact having the desired properties or functions. Design is inherently iterative and the design goals evolve together with the solutions. Many current design theories present more or less efficient ways for finding a suitable solution to the given goals. However, they often leave open the question of the ‘solution talkback’. Under ‘solution talkback’ we understand the reasoning process that is able to infer what formal amendments to the initial design specification need to be made in order to produce a feasible solution. Modified explicit design specification would in turn enable designers to refine the solutions to their design problems. This paper suggests an early-stage theory that incorporates some typical features of design problems, and defines a reasoning framework for the reflection on the actions in design. First, the key terms are defined that are elaborated later with the focus on generation of new design goals through the reflection on the partial design solutions.
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Berge, Frode, Marcus Fathi, Anne Mette Rød y Tomas Fjelde. "A Short Summary of Retrofit Multilateral Technology Implementation". En SPE/IADC International Drilling Conference and Exhibition. SPE, 2023. http://dx.doi.org/10.2118/212541-ms.
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Abstract On the Norwegian Continental Shelf there are many fields and wells in late life production. There are also many nearby drilling targets with limited volumes to add. This situation requires new mindset in order to optimize tie-ins of new reserves to existing infrastructure. Retrofit multilateral well solutions are regarded as one enabeler in this context since they enable tie-in to existing producers from nearby targets through deep sidetrack operations. There are many pre-requisites that must be in place for such solutions to be suitable. In addition, the risk of partial success involves loss of an existing producer. A few such wells have been constructed by the operator in the last couple of years. The requirements and challenges are discussed. The implementations show that it is technically feasible to use conventional multilateral technology in ways that enable installation in producing wells. Improvements to existing solutions are sought in order to facilitate future implementations and to improve robustness of this technology.
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Molina, Oscar, Laura Santos, Francisco Herrero, Agustin Monaco y Darren Schultz. "Is Decline Curve Analysis the Right Tool for Production Forecasting in Unconventional Reservoirs?" En SPE Annual Technical Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/206152-ms.
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Abstract This study presents a novel metaheuristic algorithm that uses a physics-based model for multi-fractured horizontal wells (MFHW) to accurately predict the estimated ultimate recovery (EUR) for unconventional reservoirs. The metaheuristic algorithm creates a sizeable number of stochastic simulations and keeps the simulation results from those random models that closely reproduce observed production data. Unlike other optimization methods, the proposed algorithm does not aim at finding the exact solution to the problem but a group of sufficiently accurate solutions that help to construct the partial solution to the optimization problem as a function of production history. Results from this work provide sufficient evidence as to why traditional decline curve analysis (DCA) is not a suitable solution for production forecasting in unconventional reservoirs. Two case studies are discussed in this work where results from both modeling strategies are compared. Evolutionary prediction of EUR over time using DCA behaves erratically, regardless of the amount of historical production data available to the regression model. Such erratic behavior can, in turn, yield an erroneous estimation of key economic performance indicators of an asset. In contrast, the proposed metaheuristic algorithm delivers precise and accurate results consistently, achieving a significant reduction of uncertainties as more production data becomes available. In conclusion, the proposed partial optimization approach enables the accurate calculation of important metrics for unconventional reservoirs, including production forecasting and expected productive life of an asset.
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Aguado García, Daniel, Henri Haimi, Anna Mikola, Ana Soares y Ulf Jeppsson. "Sustainable wastewater treatment solutions for water-smart circular economy". En 2nd WDSA/CCWI Joint Conference. València: Editorial Universitat Politècnica de València, 2022. http://dx.doi.org/10.4995/wdsa-ccwi2022.2022.14702.
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The Protection of aquatic water bodies and human health is a paramount objective accomplished by wastewater treatment systems. Traditionally, pollutants are managed and removed in wastewater treatment plants (WWTPs), following a paradigm in which wastewater is considered a waste. Wastewater treatment requires significant amounts of resources, such as energy and chemicals, while sludge is produced, requiring further treatment. A decade ago, a new paradigm emerged, suggesting that municipal wastewater is a source of resources, particularly reclaimed water, materials (e.g., nutrients) and energy. Many processes applicable for this new paradigm already existed, and others have been further developed (struvite-crystallization, membrane contactors, air-stripping, ionic exchange, electrodialysis, direct osmosis, etc.). Recently, resource recovery processes have been extensively developed and investigated to optimize their operation. Reclaimed water can be used for recharging aquifers, irrigation in agriculture and cooling applications. Potential risks posed by the use of reclaimed water – and of other recovered wastewater resources – must be assessed and managed during the lifecycle of the application. For example, membrane separation processes are recognised as suitable for this application to remove pathogens and particles to ensure water quality. Traditional WWTP design is based on effluent quality requirements and investment costs, with energy efficiency being only rarely considered. Larger facilities exhibit lower normalized electric consumption than smaller WWTPs, and older ones normally consume more than modern facilities (although is process dependent). For instance, in Spain it is possible to find facilities with specific electric consumptions 5-10 times higher than in modern and optimized facilities. This clearly reflects the great margin for potential energy savings. Electricity consumption at WWTPs can be reduced by improving the processes and their operation, as well as through mechanical equipment improvement. The aeration of the biological process is the major electricity consumer; thus, control strategies have been deployed to its optimization. Also, less oxygen-demanding process alternatives have been explored, like the simultaneous nitrification-denitrification operated at very low dissolved oxygen concentration. Partial nitritation and deammonification processes with low oxygen consumption per nitrogen load removed, are especially suited for treating supernatant from sludge dewatering units. However, these low energy solutions might have a downside with direct greenhouse gas GHG emissions, especially N2O. Anaerobic digestion of sludge, usually applied in large WWTPs, produces biogas that can generate both electricity and heat for local use or external use, through combined heat and power production, or liquefied biogas for external use. It is also possible to increase biogas production through co-digestion of external substrates, advanced control or sludge pre-treatment. Thermolysis processes, piloted for sewage sludge treatment, enable also waste-to-chemicals applications. There are also other possibilities for energy recovery at WWTPs, such as thermal energy via heat exchangers and heat pumps, hydropower generation using turbines, and heat from sludge incineration. Energy can be also recovered by anaerobic digestion of microalgae grown in nutrient-rich wastewater. In this paper, the transition towards sustainability and water-smart circular economy is illustrated showing how current WWTPs can be turned into Water Resource Recovery Facilities (WWRFs). The incorporation of sustainable pathways and technologies, make energy-positive facilities achievable, thus, reducing their climate impact.
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Salahshour, Soheil, Muk Chen Ong, Bjørn Skaare y Zhiyu Jiang. "A Perspective of Decommissioning Methods for Bottom-Fixed Offshore Wind Turbines". En ASME 2022 41st International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/omae2022-80933.
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Abstract The number of decommissioning activities in the offshore wind industry will increase in the coming years as many wind turbines reach their planned service lifetimes. Cost-effective solutions for decommissioning are important considering the levelized cost of energy of offshore wind farms. In addition to the existing challenges in marine operations such as waiting for suitable weather window, logistics and availability of the vessels, the limited experience in offshore wind decommissioning makes the process more challenging regarding the fact that the size of current installations of offshore wind turbines is growing considerably and more preparation and competence are required in association with new projects. In this paper, a review of existing decommissioning methods for offshore bottom-fixed wind turbines is provided first. The removal of wind turbines’ foundation and transition piece, on which significant duration of decommissioning operation is spent, is identified as a critical element, and is focused on. The decommissioning challenges and the decommissioning techniques implemented in previous projects are studied. These include partial and complete removals of foundations. These techniques and methods will be investigated thoroughly.
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Salomon Popa, Marianne, Miroslav P. Petrov y Anjaneyulu Krothapalli. "Thermoeconomic Evaluation of Integration Concepts for Solar and Biomass Hybrid Power Plants". En ASME 2013 Power Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/power2013-98116.
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Solar thermal energy and biomass fuels are often available at locations where they can benefit from combined hybrid energy utilization methods for the generation of electricity, representing suitable and advantageous integration alternatives. The feasibility of concentrating solar power (CSP) systems depends on cost limitations, desired installed power capacity and direct solar insolation, where smaller scales and low-cost solutions can often be preferred to large-scale investment-intensive installations. Biomass residues of various types, on the other hand, can be considered as proven fuels for small-to-midscale utility or industry based power or cogen arrangements and utilized through various technologies. The thermodynamic integration between a biomass fired power plant and a CSP unit can help to significantly increase the availability of the plant, improve its partial load characteristics, compensate for the intermittency of the solar energy resource while preserving the purely renewable profile of the generated electricity, and at the same time showing better overall performance when compared to two separate plants while avoiding the need for costly energy storage solutions. Biomass fuels can help reach better steam conditions in a steam plant based on CSP-generated steam, and thus improve the efficiency of energy conversion for the integrated hybrid system if compared with two individual single-fuel power units. In this study, an overview of feasible solar-biomass integration concepts is presented. A deeper thermoeconomic analysis of a selected integrated utility-scale biomass and CSP electricity generation plant is attempted, with certain simplifications. Furthermore, a multiobjective optimization strategy is regarded as very necessary and thus included in the analysis, where several major environmental aspects plus the cost of electricity are involved and defined in terms of desired parameters and conditions representative to Central Europe and Southeastern United States. The results are compared with conventional power generation alternatives. On that basis, a low-parameter CSP solution integrated with conventional biomass-fired combustion unit, where solar-generated steam is being superheated by the biomass fuel, has been chosen as the focus of the analysis in this study.
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Madiot, Ghislain, S. V. Mahmoodi-Jezeh, Stefan Tüchler, Mark Davidson, Pejman Akbari y Colin D. Copeland. "Quasi-Two-Dimensional Numerical Model for Shock Wave Reformers". En ASME Turbo Expo 2022: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/gt2022-80865.
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Abstract The article details a numerical investigation of methane pyrolysis inside a shock wave reformer using a quasi-2-dimensional (Q2D) Reynolds-Averaged Navier-Stokes (RANS) CFD model. This work is in support of the New Wave Hydrogen, Inc. (NWH2) proprietary technology development. To take account of the characteristics of the flow in the presence of shock waves, a simplified approach is proposed that captures the gas dynamics during partial opening with a lower computational cost suitable for the wave reformer design. The model is based on the three-dimensional, compressible, and unsteady Navier-Stokes equation coupled with k-ω - SST turbulence closure. Boundary conditions are implemented through a cell-centered approach with fictitious cells outside of the domain boundaries. The numerical results are compared with solutions from a quasi-one-dimensional (Q1D) unsteady model reported in literature. The simulations show a good agreement between the two different modelling approaches in terms of spatial distribution of the pressure gradient for one complete cycle. It is observed from the Q2D results that the entrance for each passage, especially upon opening of the high-pressure driver gas port, is a location of particular interest in the formation of the shock. The resulting acute pressure gradients induce loss inside the channel, decreasing the maximum temperature during a complete wave cycle by 15%, and consequently, reducing the methane pyrolysis process.
Informes sobre el tema "Partial suitable solutions"
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Delaney, Kathleen, Mark Mendelsohn, Sarah Wenner, Adam Backlin, Elizabeth Gallegos, Robert Fisher y Seth Riley. Protocol for the reintroduction of California red-legged frogs to Santa Monica Mountains National Recreation Area. National Park Service, abril de 2023. http://dx.doi.org/10.36967/2297287.
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Once common and widespread in Southern California, California red-legged frogs (Rana draytonii) began declining sometime in the middle of the 20th century. They were listed as threatened under the Endangered Species Act in 1996. Three small and isolated populations remained in Los Angeles and Ventura Counties by the start of the 21st century. The nearest population of California red-legged frogs to Santa Monica Mountains National Recreation Area is critically small, located 15 km to the north, yet there is evidence of persistence, including successful reproduction each year it has been measured. A potential solution to alleviate small population size and isolation is to reintroduce a species back to habitable historical locations nearby. In 2011, we initiated a project to reintroduce California red-legged frogs back to the Santa Monica Mountains, where historical records showed they were once widespread. We developed a procedure to transfer partial egg masses into tadpole rearing pens located within streams determined to be suitable for the species. This translocation protocol outlines our procedure and results for the first five years of the project. It is our hope that this protocol will guide and inform similar conservation efforts for California red-legged frogs in other parts of their range as well as other amphibian conservation efforts throughout the world.
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Reisch, Bruce, Avichai Perl, Julie Kikkert, Ruth Ben-Arie y Rachel Gollop. Use of Anti-Fungal Gene Synergisms for Improved Foliar and Fruit Disease Tolerance in Transgenic Grapes. United States Department of Agriculture, agosto de 2002. http://dx.doi.org/10.32747/2002.7575292.bard.
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Original objectives . 1. Test anti-fungal gene products for activity against Uncinula necator, Aspergillus niger, Rhizopus stolonifer and Botrytis cinerea. 2. For Agrobacterium transformation, design appropriate vectors with gene combinations. 3. Use biolistic bombardment and Agrobacterium for transformation of important cultivars. 4. Characterize gene expression in transformants, as well as level of powdery mildew and Botrytis resistance in foliage of transformed plants. Background The production of new grape cultivars by conventional breeding is a complex and time-consuming process. Transferring individual traits via single genes into elite cultivars was proposed as a viable strategy, especially for vegetatively propagated crops such as grapevines. The availability of effective genetic transformation procedures, the existence of genes able to reduce pathogen stress, and improved in vitro culture methods for grapes, were combined to serve the objective of this proposal. Effective deployment of resistance genes would reduce production costs and increase crop quality, and several such genes and combinations were used in this project. Progress The efficacy of two-way combinations of Trichoderma endochitinase (CHIT42), synthetic peptide ESF12 and resveratrol upon the control of growth of Botrytis cinerea and Penicillium digitatum were evaluated in vitro. All pairwise interactions were additive but not synergistic. Per objective 2, suitable vectors with important gene combinations for Agrobacterium transformation were designed. In addition, multiple gene co-transformation by particle bombardment was also tested successfully. In New York, transformation work focused on cultivars Chardonnay and Merlot, while the technology in Israel was extended to 41B, R. 110, Prime, Italia, Gamay, Chardonnay and Velika. Transgenic plant production is summarized in the appendix. Among plants developed in Israel, endochitinase expression was assayed via the MuchT assay using material just 1-5 days after co-cultivation. Plants of cv. Sugraone carrying the gene coding for ESF12, a short anti-fungal lytic peptide under the control of the double 358 promoter, were produced. Leaf extracts of two plants showed inhibition zones that developed within 48 h indicating the inhibitory effect of the leaf extracts on the six species of bacteria. X fastidiosa, the causal organism of Pierce's disease, was very sensitive to leaf extracts from ESF12 transformed plants. Further work is needed to verify the agricultural utility of ESF12 transformants. In New York, some transformants were resistant to powdery mildew and Botrytis fruit rot. Major conclusions, solutions, achievements and implications The following scientific achievements resulted from this cooperative BARD project: 1. Development and improvement of embryogenesis and tissue culture manipulation in grape, while extending these procedures to several agriculturally important cultivars both in Israel and USA. 2. Development and improvement of novel transformation procedures while developing transformation techniques for grape and other recalcitrant species. 3. Production of transgenic grapevines, characterization of transformed vines while studying the expression patterns of a marker gene under the control of different promoter as the 35S CaMV in different part of the plants including flowers and fruits. 4. Expression of anti-fungal genes in grape: establishment of transgenic plants and evaluation of gene expression. Development of techniques to insert multiple genes. 5. Isolation of novel grape specific promoter to control the expression of future antimicrobial genes. It is of great importance to report that significant progress was made in not only the development of transgenic grapevines, but also in the evaluation of their potential for increased resistance to disease as compared with the non engineered cultivar. In several cases, increased disease resistance was observed. More research and development is still needed before a product can be commercialized, yet our project lays a framework for further investigations.