scholarly journals Modifications to Kozeny–Carman model to enhance petrophysical relationships

2017 ◽  
Author(s):  
Amir M. S. Lala

Abstract. The most commonly used relationship relates permeability to porosity, grain size, and tortuosity is Kozeny–Carman formalism. When it is used to estimate the permeability behavior versus porosity, the other two parameters (the grain size and tortuosity) are usually kept constant. Here, we investigate the deficiency of the Kozeny–Carman assumption and offer alternative derived equations for the Kozeny–Carman equation, including equations where the grain size is replaced with the pore size and with varying tortuosity. We also introduced relationships for the permeability of shaly sand reservoir that answer the approximately linear permeability decreases in the log-linear permeability-porosity relationships in datasets from different locations.

2007 ◽  
Vol 558-559 ◽  
pp. 1201-1206 ◽  
Author(s):  
Mihaela Teodorescu ◽  
Patrice Lasne ◽  
Roland E. Logé

The present work concerns the simulation of metallurgical evolutions in 3D multi-pass forming processes. In this context, the analyzed problem is twofold. One point refers to the management of the microstructure evolution during each pass or each inter-pass period and the other point concerns the management of the multi-pass aspects (different grain categories, data structure). In this framework, a model is developed and deals with both aspects. The model considers the microstructure as a composite made of a given (discretized) number of phases which have their own specific properties. The grain size distribution and the recrystallized volume fraction distribution of the different phases evolve continuously during a pass or inter-pass period. With this approach it is possible to deal with the heterogeneity of the microstructure and its evolution in multi-pass conditions. Both dynamic and static recrystallization phenomena are taken into account, with typical Avrami-type equations. The present model is implemented in the Finite Element code FORGE2005®. 3D numerical simulation results for a multi-pass process are presented.


2013 ◽  
Vol 203-204 ◽  
pp. 258-261 ◽  
Author(s):  
Izabela Kalemba ◽  
Krzysztof Muszka ◽  
Mirosław Wróbel ◽  
Stanislaw Dymek ◽  
Carter Hamilton

This research addresses the EBSD analysis of friction stir welded 7136-T76 aluminum alloy. The objectives of this study were to evaluate the grain size and their shape, character of grain boundaries in the stirred and thermo-mechanically affected zones, both on the advancing and retreating side as well as to investigate changes in the crystallographic texture. Results of texture analysis indicate the complexity of the FSW process. The texture gradually weakens on moving from the thermo-mechanically affected zone toward the weld center. The stirred zone is characterized by very weak texture and is dominated by high angle boundaries. On the other hand, the thermo-mechanically affected zone exhibits a high frequency of low angle boundaries.


Water ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 2823
Author(s):  
Yanguang Liu ◽  
Chuanshun Li ◽  
Ramlan Bin Omar ◽  
Xuefa Shi ◽  
Hui Zhang ◽  
...  

Thirty-nine surface sediment samples collected from the western Sunda Shelf off the Malay Peninsula (WSSMP) in the southern South China Sea (SCS) were analysed for grain size, major and trace elemental compositions, and light/heavy mineral contents to trace the sediment sources and their transport mechanisms in the study area. In the WSSMP, the surface sediments are relatively poorly sorted but transportable. A principal component analysis of 37 elements and grain size fractions indicates that the surface sediments can be grouped into four major assemblages in the study area. Integrating with the light/heavy minerals data in the 63–125 μm fractions of the surface sediment samples, to better trace the sediment sources of the coarse-grained components in the marine environment, the study area can be further divided into four sediment provinces. Province I is located in the northwestern part of the study area. The concentrations of TiO2, Na2O, garnet, siderite, and glauconite in Province I were higher than in the other provinces. The main sediment source for this province originated from the Kelantan River and the Gulf of Thailand transported by the northeastern monsoon current. Province II is located offshore of the Pahang and Endau Rivers. The percentages of TiO2, rare earth elements, Al2O3, quartz, plagioclase, hypersthene, and magnetite in the surface sediments were typically higher in this province than in the other provinces. The Pahang and Endau rivers provide most of the sediments to this province, which are transported by southward coastal currents. Province III is located in the northeastern and eastern parts of the study area, where the coarse-grained sediment fraction had relatively high hornblende and biotite contents. Sediments in this province are mostly transported from the Mekong River during the northeastern monsoon. The other parts of the study area belong to Province IV, where the surface sediment elemental and mineral concentrations were mostly between those of the other three provinces. Therefore, we suggest that Province IV has a mixed source due to inputs from the surrounding rivers.


2021 ◽  
Vol 5 (4) ◽  
pp. 152
Author(s):  
Shao-Heng He ◽  
Zhi Ding ◽  
Hai-Bo Hu ◽  
Min Gao

In this study, a series of nuclear magnetic resonance (NMR) tests was conducted on calcareous sand, quartz sand, and glass bead with a wide range of grain sizes, to understand the effect of grain size on the micro-pore structure and fractal characteristics of the carbonate-based sand and silicate-based sand. The pore size distribution (PSD) of the tested materials were obtained from the NMR T2 spectra, and fractal theory was introduced to describe the fractal properties of PSD. Results demonstrate that grain size has a significant effect on the PSD of carbonate-based sand and silicate-based sand. As grain size increases, the PSD of sands evolves from a binary structure with two peaks to a ternary structure with three peaks. The increase in the grain size can cause a remarkable increase in the maximum pore size. It is also found that the more irregular the particle shape, the better the continuity between the large and medium pores. In addition, grain size has a considerable effect on the fractal dimension of the micro-pore structure. The increase of grain size can lead to a significant increase in the heterogeneity and fractal dimension in PSD for calcareous sand, quartz sand and glass bead.


Author(s):  
Duangui Wang

Formulation of the problem. In the chamber-vocal genre, the composer exists in two images: he is both the interpreter of the poetic composition and the author of a new synthetic music and poetic composition. The experience of the style analysis of one of the best examples of Ukrainian vocal lyrics of the first third of the 20th century shows that the cycle op. 20 characterizes the mature style of the composer, which was formed, on the one hand, under the influence of European Romanticism. On the other hand, the essence of the Ukrainian “branch” of the Western European song-romance (“solo-singing”) is revealed by the prominent national song-romance intonation, filled with not only a romantic worldview, but also with some personal sincerity, chastity, intimate involvement with the great in depth and simplicity poetry line, read from the individual position of the musician. The paradox is as follows. Although Pushkin’s poetry is embodied in a “holistic adequacy” (A. Khutorskaya), and the composer found the fullest semantic analogue of the poetic source, however, in terms of translating the text into the Ukrainian language, the musical semantics changes its intonation immanence, which naturally leads to inconsistency of the listeners’ position and ideas about the style of Russian romance. We are dealing with inter-specific literary translation: Pushkin’s discourse creates the Ukrainian romance style and system of figurative thinking. The purpose of the article is to reveal the principle of re-semantization of the intonation-figurative concept of the vocal composition by V. Kosenko (in the context of translating Pushkin’s poetry into the Ukrainian language) in light of the theory of interspecific art translation. Analysis of recent publications on the topic. Among the most recent studies of Ukrainian musicology, one should point out the dissertation by G. Khafizova (Kyiv, 2017), in which the theory of modelling of the stylistic system of the vocal composition as an expression of Pushkin’s discourse is described. The basis for the further stylistic analysis of V. Kosenko’s compositions is the points from A. Hutorska’s candidate’s thesis; she develops the theory of interspecific art translation. The types of translation of poetry into music are classified according to two parameters. The exact translation creates integral adequacy, which involves the composer’s finding a maximally full semantic analogue of the poetic source. The free translation is characterized by compensatory, fragmentary, generalized-genre adequacy. Presenting the main material. The Zhitomir period for Viktor Kosenko was the time of the formation of his creative style. Alongside the lyrical imagery line, the composer acquired one more – dramatic, after his mother’s death. It is possible that the romances on the poems of A. Pushkin are more late reflection of this tragic experience (op. 20 was created in 1930). “I Loved You” opens the vocal cycle and has been dedicated by A. V. Kosenko. The short piano introduction contains the intonation emblem of the love-feeling wave. The form of the composition is a two part reprising (А А1) with the piano Introduction and Postlude. The semantic culmination is emphasized by the change of metro-rhythmic organization 5/4 (instead of 4) and the plastic phrase “as I wish, that the other will love you” sounding in the text. Due to these melodies (with national segments in melo-types, rhythm formulas and harmony) V. Kosenko should be considered as “Ukrainian Glinka”, the composer who introduced new forms and “figures” of the love language into the romantic “intonation dictionary”. In general, V. Kosenko’s solo-singing represents the Ukrainian analogue of Pushkin’s discourse – the theme of love. The melos of vocal piece “I Lived through My Desires” is remembered by the broad breath, bright expression of the syntactic deployment of emotion. On the background of bass ostinato, the song intonation acquires a noble courage. This solo-singing most intermediately appeal to the typical examples of the urban romance of Russian culture of the 19th century. “The Raven to the Raven” – a Scottish folk ballad in the translation by A. Pushkin. V. Kosenko as a profound psychologist, delicately transmits the techniques of versification, following each movement of a poetic phrase, builds stages of the musical drama by purely intonation means. The semantics of a death is embodied through the sound imaging of a black bird: a marching-like tempo and rhythm of the accompaniment, with a characteristic dotted pattern in a descending motion (like a raven is beating its wings). The middle section is dominated by a slow-motion perception of time space (Andante), meditative “freeze” (size 6/4). The melody contrasts with the previous section, its profile is built on the principle of descending move: from “h1” to “h” of the small octave (with a stop on S-harmony), which creates a psychologically immersed state, filled by premonition of an unexpected tragedy. In general, the Ukrainian melodic intonation intensified the tragic content of the ballad by Pushkin. The musical semantics of V. Kosenko’s romances is marked by the dependence on the romantic “musical vocabulary”, however, it is possible to indicate and national characteristics (ascending little-sixth and fifth intervals, which is filled with a gradual anti-movement; syllabic tonic versification, and other). Conclusion. The romances (“solo-singings”) by V. Kosenko belongs to the type of a free art translation with generalized-genre adequacy. There is a re-semantization of poetic images due to the national-mental intonation. Melos, rhythm, textural presentation (repetitions), stylization of different genre formulas testify to the rare beauty of Kosenko’s vocal style, spiritual strength and maturity of the master of Ukrainian vocal culture. Entering the “Slavic song area”, the style of Ukrainian romance, however, is differenced from the Russian and common European style system of figurative and intonation thinking (the picture of the world).


Author(s):  
R. Randall Soper ◽  
Michael Scardina ◽  
Paul Tidwell ◽  
Charles Reinholtz ◽  
Michael A. Lo Presti

Abstract This paper presents a technique for synthesizing four-bar linkages to produce a specified resisting force or torque. The resisting energy is provided by a weight acting on the other grounded link. The linkage serves as a nonlinear mechanical advantage function generator. Force and velocity synthesis methods have been extensively discussed in the literature. The general approach, however, has been to assume that the specified force or velocity occurs at a prescribed position. This results in the loss of design parameters that are being used unnecessarily to control position. In this application, force input to the linkage is specified as a function of only the input link position and the magnitude and direction of the weight force. Mechanical advantage synthesis can be achieved at as many as seven precision points. The method presented in this paper allows free selection of two parameters and viewing one infinity of solutions.


Author(s):  
Therese M. Donovan ◽  
Ruth M. Mickey

This chapter introduces Markov Chain Monte Carlo (MCMC) with Gibbs sampling, revisiting the “Maple Syrup Problem” of Chapter 12, where the goal was to estimate the two parameters of a normal distribution, μ‎ and σ‎. Chapter 12 used the normal-normal conjugate to derive the posterior distribution for the unknown parameter μ‎; the parameter σ‎ was assumed to be known. This chapter uses MCMC with Gibbs sampling to estimate the joint posterior distribution of both μ‎ and σ‎. Gibbs sampling is a special case of the Metropolis–Hastings algorithm. The chapter describes MCMC with Gibbs sampling step by step, which requires (1) computing the posterior distribution of a given parameter, conditional on the value of the other parameter, and (2) drawing a sample from the posterior distribution. In this chapter, Gibbs sampling makes use of the conjugate solutions to decompose the joint posterior distribution into full conditional distributions for each parameter.


2021 ◽  
Vol 1016 ◽  
pp. 125-131
Author(s):  
Masahiro Goto ◽  
T. Yamamoto ◽  
S.Z. Han ◽  
J. Kitamura ◽  
J.H. Ahn ◽  
...  

On the thermomechanical treatments of Cu-Ni-Si alloy, cold-rolling (CR) before solution heat treatment (SHT) is commonly conducted to eliminate defects in a casting slab. In addition, a rolling is applied to reduce/adjust the thickness of casting slab before SHT. In a heavily deformed microstructure by CR, on the other hand, grain growth during a heating in SHT is likely to occur as the result of recrystallization. In general, tensile strength and fatigue strength tend to decrease with an increase in the grain size. However, the effect of difference in grain sizes produced by with and without CR before SHT on the fatigue strength is unclear. In the present study, fatigue tests of Cu-6Ni-Si alloy smooth specimens with a grain fabricated through different thermomechanical processes were conducted. The fatigue behavior of Cu-Ni-Si alloy was discussed.


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