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, M. Piana, V. Ruggiero, M. Scussolini
SIAM Journal on Imaging Sciences, Volume 14, pp 418-439; https://doi.org/10.1137/20m1336370

Abstract:
Parametric imaging of nuclear medicine data exploits dynamic functional images in order to reconstruct maps of kinetic parameters related to the metabolism of a specific tracer injected in the biological tissue. Classical approaches to parametric imaging rely on linearized schemes that, on the one hand, are computationally effective but, on the other hand, provide information just on a very limited number of parameters (typically two). Possible nonlinearized approaches require the pixelwise numerical solution of compartmental nonlinear ill-posed inverse problems and therefore typically imply a notable computational burden. In the present paper we introduce a fast numerical optimization scheme for parametric imaging relying on a regularized version of the standard affine-scaling trust-region method. The main advantages of this approach are both that it is a regularization method (and therefore it reduces the numerical instabilities in the reconstructed images) and that it is significantly faster than other algorithms in the optimization market (and therefore it may be utilized for clinical applications). The validation of this approach is realized in a simulation framework for brain imaging and also in the case of an experimental set of nuclear medicine data acquired from a murine model. Comparison of performances is made with respect to a regularized Gauss--Newton scheme and a standard nonlinear bound-constrained least-squares algorithm.
Roberto Emparan, Christopher P. Herzog
Published: 25 March 2020
Abstract:
We review recent progress in taking the large dimension limit of Einstein's equations. Most of our analysis is classical in nature and concerns situations where there is a black hole horizon although we briefly discuss various extensions that include quantum gravitational effects. The review consists of two main parts: the first a discussion of general aspects of black holes and effective membrane theories in this large dimension limit, and the second a series of applications of this limit to interesting physical problems. The first part includes a discussion of quasinormal modes which leads naturally into a description of effective hydrodynamic-like equations that describe the near horizon geometry. There are two main approaches to these effective theories -- a fully covariant approach and a partially gauge-fixed one -- which we discuss in relation to each other. In the second part we divide the applications up into three main categories: the Gregory-Laflamme instability, black hole collisions and mergers, and the anti-de Sitter/conformal field theory correspondence (AdS/CFT). AdS/CFT posits an equivalence between a gravitational theory and a strongly interacting field theory, allowing us to extend our spectrum of applications to problems in hydrodynamics, condensed matter physics, and nuclear physics. A final, shorter part of the review describes further promising directions where there have been, as yet, few published research articles.
, Alexey Svyatkovskiy, William Tang
Published: 17 April 2019
Nature, Volume 568, pp 526-531; https://doi.org/10.1038/s41586-019-1116-4

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A.Yu. Pogosov, O.V. Derevianko
Radio Electronics, Computer Science, Control pp 53-60; https://doi.org/10.15588/1607-3274-2017-2-6

Abstract:
Context. The topical approaches to preventive estimations and mathematical modeling of cyber attacks processes and supply of external technological informational threats were considered, which may be directed on the physical security system of modern nuclear power plant units.Objective – is an adaptation of known mathematical models of cyber attacks kinetics for use in the system of information security and physical protection of nuclear power plants to modern and foreseeable conditions.Method. The method of model dependencies adaptation was proposed, which reflects the kinetics of cyberattacks to the modern operating conditions of protected nuclear facilities was proposed. To improve the model dependencies it was proposed to modify the classic Ferhulst function and, in mathematical modeling of cyber attacks on nuclear power facilities, to use the appropriate transformation of the logistic curve, which has distinctive feature of a well-defined maximum.Results. It was predicted that the model dependence of flow external to NPP cyber threats can be characterized by the alternation of maxima and minima, which indicates the possibility of an oscillatory character of the developing process. Also was put forward and substantiated the hypothesis that the system of physical and, in particular, cybernetic, NPP protection can be characterized by a time lag that in view of possible oscillatory character of information threats admissions process creates the preconditions for the development of oscillatory instability.The results obtained in the research are of applied nature, they can be used to carry out large-scale experiments and forecasting parameters of possible cyber threats aimed at the NPP for the purpose of pre-emption and preventive maintenance of information safety of modern nuclear energy technologies.Conclusions. Recommended for use model dependences were first adapted to the conditions of operating conditions of nuclear powerfacilities, take into account the factors to counter threats and circumstances associated with a specific time delay.It was shown for the first time that there is an opportunity both extreme and oscillatory dependence nature of the cyber attacks intensity, which are focused on software and hardware system of NPP information safety. The new approach allows to assume the reality of the unstable oscillation process in the “attack – defense” system and provides an opportunity of preventive assessment of the stability stocks.The practical significance lies in the fact that the results allow to realistically assess the time of onset of expected cyber attacks current dependence changes and to use this knowledge for organizational and technical preparation of remedies and early anticipation of IT-threats.
Reinaldo Franqui Machin, Xin Zhan, Hongwei Xu, Ivana Frech, Guido J Tricot, Fenghuang Zhan
Published: 2 December 2016
Blood, Volume 128, pp 4418-4418; https://doi.org/10.1182/blood.v128.22.4418.4418

Abstract:
NIMA (Never In Mitosis Gene A)-Related Kinase 2 (Nek2), a centrosomal Serine/Threonine kinase, is a key player in numerous malignancies. Overexpression of Nek2 has been related to many cancers including Multiple Myeloma (MM). In MM, Nek2 is one of the chromosomal instability genes associated with drug resistance and disease relapse. However, very little is known about the mechanisms that lead to these Nek2-driven disparities. Here, we show that the Ubiquitin Specific Peptidase 7 (USP7) stabilizes Nek2 leading to activation of NF-kb pathway. Using gene expression profile (GEP) data from patients and cell lines we discovered that Nek2 overexpression leads to increases of several targets of the NF-kb pathway. We, thus, hypothesize that Nek2 is activating NF-kb. To address this, we overexpressed Nek2 and tested the classic canonical NF-kb hallmarks proteins by western blotting. Nek2 overexpression led to an increase in phosphorylation of IKK, activator of NF-kb, and to decrease levels of IKb-alpha, a negative regulator of the pathway. Nek2 overexpression also increased nuclear and phosphorylated p65 on residue S536, known as active transcriptional site. To further confirm that Nek2 is activating canonical NF-kb luciferase assay was performed. The luciferase reporter is driven by a p65 promoter and in cells overexpressing Nek2 luciferase levels were increased. To characterize Nek2 interacting partners a tandem affinity purification/mass spectrometry (TAP/MS) approach was performed. We found that Nek2 binds to Usp7, a deubiquitinase overexpressed in numerous cancers. This led to hypothesize that that Nek2, a known target of the ubiquitin proteasome system, is being stabilized by the Usp7 contributing to its overexpression and the increased activation of the NF-kb pathway. To test our hypothesis, we treated different cancer cell lines with the commercially available Usp7 inhibitor, P5091, or silenced the protein using shRNA. In both case, we found a reduction in Nek2 protein level. Additionally, we overexpressed Usp7 and Nek2 increased confirming that Usp7 stabilizes Nek2. To further show that Usp7 stabilizes Nek2 by de-ubiquitination, we overexpressed Usp7 and analyzed Nek2 ubiquitination after immunoprecipitation. When Usp7 was overexpressed no ubiquitination of Nek2 was detected. Finally, by using GEP data from MM patients, we found that individuals who overexpressed Nek2 along with an active NF-kb signature have worst event free survival as well as overall survival, indicating Nek2 overexpression leading to increased NF-kb signature has clinical significance. Disclosures No relevant conflicts of interest to declare.
Laura L. Thompson,
Published: 20 April 2015
Abstract:
Chromosome instability (CIN) is characterized by a progressive change in chromosome numbers. It is a characteristic common to virtually all tumor types, and is commonly observed in highly aggressive and drug resistant tumors. Despite this information, the majority of human CIN genes have yet to be elucidated. In this study, we developed and validated a multiplexed, image-based screen capable of detecting three different phenotypes associated with CIN. Large-scale chromosome content changes were detected by quantifying changes in nuclear volumes following RNAi-based gene silencing. Using a DsRED-LacI reporter system to fluorescently label chromosome 11 within a human fibrosarcoma cell line, we were able to detect deviations from the expected number of two foci per nucleus (one focus/labelled chromosome) that occurred following CIN gene silencing. Finally, micronucleus enumeration was performed, as an increase in micronucleus formation is a classic hallmark of CIN. To validate the ability of each assay to detect phenotypes that underlie CIN, we silenced the established CIN gene, SMC1A. Following SMC1A silencing we detected an increase in nuclear volumes, a decrease in the number of nuclei harboring two DsRED-LacI foci, and an increase in micronucleus formation relative to controls (untreated and siGAPDH). Similar results were obtained in an unrelated human fibroblast cell line. The results of this study indicate that each assay is capable of detecting CIN-associated phenotypes, and can be utilized in future experiments to uncover novel human CIN genes, which will provide novel insight into the pathogenesis of cancer.
O. Yılmaz, , F. Acar, A. Gokalp
Published: 23 January 2015
Abstract:
Early growth of density fluctuations of nuclear matter in spinodal region is investigated employing the stochastic mean-field approach. In contrast to the earlier treatments in which only collective modes were included in the calculations, in the present work non-collective modes are also included, thus providing a complete treatment of the density correlation functions. Calculations are carried out for symmetric matter in non-relativistic framework using a semi-classical approximation.
Published: 12 August 2013
BMC Genetics, Volume 14, pp 70-70; https://doi.org/10.1186/1471-2156-14-70

Abstract:
Background The taxonomic and phylogenetic relationships of the genus Phyllomedusa have been amply discussed. The marked morphological similarities among some species hamper the reliable identification of specimens and may often lead to their incorrect taxonomic classification on the sole basis of morphological traits. Phenotypic variation was observed among populations assigned to either P. azurea or P. hypochondrialis. In order to evaluate whether the variation observed in populations assigned to P. hypochondrialis is related to that in genotypes, a cytogenetic analysis was combined with phylogenetic inferences based on mitochondrial and nuclear sequences. Results The inter- and intra-population variation in the external morphology observed among the specimens analyzed in the present study do not reflect the phylogenetic relationships among populations. A monophyletic clade was recovered, grouping all the specimens identified as P. hypochondrialis and specimens assigned P. azurea from Minas Gerais state. This clade is characterized by conserved chromosomal morphology and a common C-banding pattern. Extensive variation in the nucleolar organizing region (NOR) was observed among populations, with four distinct NOR positions being recognized in the karyotypes. Intra-population polymorphism of the additional rDNA clusters observed in specimens from Barreiras, Bahia state, also highlights the marked genomic instability of the rDNA in the genome of this group. Based on the topology obtained in the phylogenetic analyses, the re-evaluation of the taxonomic status of the specimens from the southernmost population known in Brazil is recommended. Conclusions The results of this study support the need for a thorough revision of the phenotypic features used to discriminate P. azurea and P. hypochondrialis. The phylogenetic data presented here also contribute to an extension of the geographic range of P. hypochondrialis, which is known to occur in the Amazon basin and neighboring areas of the Cerrado savanna, where it may be sympatric with P. azurea, within contact zones. The misidentification of specimens may have led to inconsistencies in the original definition of the geographic range of P. azurea. The variability observed in the NOR of P. hypochondrialis reinforces the conclusion that these sites represent hotspots of rearrangement. Intraspecific variation in the location of these sites is the result of constant rearrangements that are not detected by classical cytogenetic methods or are traits of an ancestral, polymorphic karyotype, which would not be phylogenetically informative for this group.
Physical Review C, Volume 84; https://doi.org/10.1103/physrevc.84.064308

Abstract:
A modified variable phase method for the numerical solution of coupled radial Schrödinger equations, which maintains linear independence for different sets of solution vectors, is suggested. The modification involves rearrangement of coupled equations to avoid the usual numerical instabilities associated with components of the wave function in their classically forbidden regions. The modified method is applied to nuclear structure calculations of halo nuclei within the hyperspherical harmonics approach. DOI: http://dx.doi.org/10.1103/PhysRevC.84.064308 ©2011 American Physical Society
Marco R. De Baar, Waldo A. Bongers, Matthijs Van Berkel, Niek J. Doelman, Bart A. Hennen, Pieter Nuij, Johan W. Oosterbeek, , , Gert Witvoet
2010 IEEE International Conference on Control Applications pp 294-300; https://doi.org/10.1109/cca.2011.6044376

Abstract:
Resistive magneto-hydrodynamic instabilities are expected to limit the performance of nuclear fusion reactors. Prime examples are the sawtooth instability and the neoclassical tearing modes. The sawtooth instability will affect the refueling of the plasma core and the fast particle concentration. In reactor relevant conditions, the sawtooth can also trigger secondary instabilities. These are the neo-classical tearing modes, which can deteriorate the plasma performance or even disrupt the discharge. These modes (sawteeth and tearing modes) appear at specific locations in the tokamak plasma, associated with the distribution of the current density and the toroidal magnetic field. Localized current drive from electron cyclotron waves is foreseen as a possible actuator for the width of the tearing modes and the period of the sawteeth. Magnetic pick-up coils, electron cyclotron emission (ECE) and soft X-ray emission are the most likely sensors. A system approach for real-time detection, localisation and control of resistive magneto-hydrodynamic modes in tokamaks is presented. The system combines an ECE diagnostic for sensing of the instabilities in the same sight-line with a steerable Electron Cyclotron Resonant Heating and Current Drive (ECRH/CD) antenna. A model for the sawtooth is used to derive the linearized input-output relations (transfer functions) from the varying deposition location of high power Electron Cyclotron waves to the sawtooth period. The transfer functions are derived around a large collection of operating points. Proportional-integral-integral (PII) action can be applied to achieve fast and perfect tracking, while satisfying robustness constraints. The launcher dynamics seriously affects the closed loop performance in present-day experiments. Special emphasis is put on the issue of real-time sawtooth period detection. An algorithm based on time-scale wavelet theory and edge detection for accurate real-time sawtooth period estimation has been developed. The period is estimated by detecting subsequent crashes. The realized accuracy of the detection algorithm is well below the uncertainty of the crash period for most crashes. Multi-resolution analysis enables distinction between different sizes of sawtooth crashes due to the different sizes of wavelets (scales), resulting in an algorithm, which is robust and accurate. A methodology for fast detection of q = m/n = 2/1 tearing modes and retrieval of their location, rotation frequency and phase is presented. Set-points to establish alignment of the ECRH/CD deposition location with the centre of the tearing mode are generated in real-time and forwarded in closed-loop to the steerable launcher and as a modulation pulse train to the gyrotron.
, J. S. Vaagen, M. V. Zhukov
Physics of Atomic Nuclei, Volume 74, pp 1151-1161; https://doi.org/10.1134/s1063778811080060

Abstract:
One of the major problems in numerical solution of coupled differential equations is the maintenance of linear independence for different sets of solution vectors. A novel method for solution of radial Schrödinger equations is suggested. It consists of rearrangement of coupled equations in a way that is appropriate to avoid usual numerical instabilities associated with components of the wave function in their classically forbidden regions. Applications of the new method for nuclear structure calculations within the hyperspherical harmonics approach are given.
C. Benedetti, P. Londrillo, T.V. Liseykina, , , G. Turchetti
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 606, pp 89-93; https://doi.org/10.1016/j.nima.2009.03.214

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S. Ayik, N. Er, O. Yilmaz, A. Gokalp
Published: 1 November 2008
Nuclear Physics A, Volume 812, pp 44-57; https://doi.org/10.1016/j.nuclphysa.2008.08.007

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, N. Er, O. Yılmaz, A. Gokalp
Published: 1 August 2008
Abstract:
Quantal effects on growth of spinodal instabilities in charge asymmetric nuclear matter are investigated in the framework of a stochastic mean field approach. Due to quantal effects, in both symmetric and asymmetric matter, dominant unstable modes shift towards longer wavelengths and modes with wave numbers larger than the Fermi momentum are strongly suppressed. As a result of quantum statistical effects, in particular at lower temperatures, magnitude of density fluctuations grows larger than those calculated in semi-classical approximation.
Ze-Hong Miao, Audrey Player, Uma Shankavaram, Yong-Hong Wang, Drazen B. Zimonjic, Philip L. Lorenzi, Zhi-Yong Liao, Hong Liu, Tsutomu Shimura, Hong-Liang Zhang, et al.
Cancer Research, Volume 67, pp 8752-8761; https://doi.org/10.1158/0008-5472.can-06-4554

Abstract:
The biological functions of nuclear topoisomerase I (Top1) have been difficult to study because knocking out TOP1 is lethal in metazoans. To reveal the functions of human Top1, we have generated stable Top1 small interfering RNA (siRNA) cell lines from colon and breast carcinomas (HCT116-siTop1 and MCF-7-siTop1, respectively). In those clones, Top1 is reduced ∼5-fold and Top2α compensates for Top1 deficiency. A prominent feature of the siTop1 cells is genomic instability, with chromosomal aberrations and histone γ-H2AX foci associated with replication defects. siTop1 cells also show rDNA and nucleolar alterations and increased nuclear volume. Genome-wide transcription profiling revealed 55 genes with consistent changes in siTop1 cells. Among them, asparagine synthetase (ASNS) expression was reduced in siTop1 cells and in cells with transient Top1 down-regulation. Conversely, Top1 complementation increased ASNS, indicating a causal link between Top1 and ASNS expression. Correspondingly, pharmacologic profiling showed l-asparaginase hypersensitivity in the siTop1 cells. Resistance to camptothecin, indenoisoquinoline, aphidicolin, hydroxyurea, and staurosporine and hypersensitivity to etoposide and actinomycin D show that Top1, in addition to being the target of camptothecins, also regulates DNA replication, rDNA stability, and apoptosis. Overall, our studies show the pleiotropic nature of human Top1 activities. In addition to its classic DNA nicking-closing functions, Top1 plays critical nonclassic roles in genomic stability, gene-specific transcription, and response to various anticancer agents. The reported cell lines and approaches described in this article provide new tools to perform detailed functional analyses related to Top1 function. [Cancer Res 2007;67(18):8752–61]
S. V. Radionov, , V. M. Kolomietz, A. G. Magner
Physics of Atomic Nuclei, Volume 65, pp 824-830; https://doi.org/10.1134/1.1481473

Abstract:
We evaluate the temperature Tscis at the scission point and the saddle-to-scission time τscis for the fission of heated nuclei. We use classical Lagrange-like equations of motion within the liquid-drop model. The nuclear surface is parameterized by a two-parameter family of the Lawrence shapes. Conservative forces are defined through the free energy of the nucleus at finite temperatures. We use the friction tensor that is derived from the Navier-Stokes momentum-flux tensor and which takes into account the boundary conditions at the nuclear surface. The scission line is determined from the instability condition of the nuclear shape with respect to variations of the neck radius. A numerical solution to the dynamical equations is obtained for the 236U nucleus. The viscosity coefficient μ is deduced from a comparison of experimental data on the kinetic energy of fission fragments with the computed one. It is found that μ obtained by using our approach deviates significantly from μ of the standard hydrodynamic model.
L-F Li, K K Phua, S S M Wong, B-L Young
First International Conference on Frontiers of Physics pp 1-1099; https://doi.org/10.1142/9789814529846

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D. Guinet
Second European Biennial Conference pp 1-444; https://doi.org/10.1142/9789814535489

The publisher has not yet granted permission to display this abstract.
Published: 1 March 1995
Contemporary Physics, Volume 36, pp 121-136; https://doi.org/10.1080/00107519508222146

Abstract:
Algebraic Approach to Simple Quantum Systems. By B. G. Adams. (Springer, 1994.) [pp. xvi + 451.] DM68.00 (pbk). ISBN 3 540 57801 3. Scope: monograph. Level: postgraduate and specialist. A Life of Erwin Schrödinger By W. MOORE. (Cambridge University Press, 1994.) [pp. xiii + 349] £11.95 (hbk), £7.95 (pbk). ISBN 0 521 46934 1. Scope: biography. Level: general reader. A Primer of Nonlinear Analysis By A. AMBROSETTI and G. PRODI. (Cambridge University Press, 1993.) [pp. viii + 171.] US$39.95 (hbk). ISBN 0 521 37390 5. Scope: text. Level: postgraduate and specialist. Basic Thermodynamics By G. CARRINGTON. (Oxford University Press, 1994.) [pp.xi + 385.] £40.00 (hbk). ISBN 0 198 51747 5. Scope: textbook. Level: undergraduate. Chemical Oscillations and Instabilities By P. GRAY and S. K. SCOTT 1994, £25·00 (pbk) pp. xvi + 453. Oxford, ISBN 0 19 855864 3. Scope: monograph. Level: postgraduate and specialist. Classical and Quantum Dynamics from Classical Paths to Path Integrals. 2nd Revised Edn. By W. DITTRICH and M. REUTER. (Springer, 1994.) [pp. 361.] DM52.00, SFr. 52.00 (pbk). ISBN 3 540 56245 1. Scope: textbook. Level: graduate student. Foundations of Astronomy By M. A. SEEDS (Wadsworth, 1995.) [pp. xviii + 701.] £21.95 (hbk). ISBN 0 534 21511 X. Scope: textbook. Level: undergraduate and general reader. From Electrostatics to Optics, A Concise Electrodynamics Course By G. SCHARF. (Springer, 1994.) [pp. viii + 255.] DM58.00, SFr58.00 (hbk) ISBN 3 540 51682 7. Scope: textbook. Level: advanced undergraduate and postgraduate. Fundamental Astronomy. 2nd Enlarged Edn. Edited by H. KARTTUNEN et al (Springer, 1994.) [pp. xiii + 511.] DM78.00, SFr78.00 (pbk). ISBN 3 540 57203 1. Scope: textbook. Level: undergraduate. Fundamentals of Crystals: Symmetry, and Methods of Structural Crystallography (2nd, enlarged edition). By BORIS K. VAINSHTEIN. 1994, £47·00 (hbk), pp. viii +480. Springer, ISBN 3 540 565582. Scope: text. Level: postgraduate and specialist. Group Theory and Physics By S. STERNBERG. (Cambridge University Press, 1994) [pp. xiii + 429.] £50.00, US$69.95 (hbk). ISBN 0 521 24870 1. Scope: monograph. Level: postgraduate and specialist. High Energy Astrophysics, Volume 2 By M. S. LONGAIR 1994, £45·00, US$69·95 (hbk), £16·95, US$34·95 (pbk), pp. xvii + 393. Cambridge, ISBN 0 521 43584 6. Scope: textbook. Level: undergraduate and postgraduate. Inside Versus Outside, Endo-and Exo-Concepts of Observation and Knowledge in Physics, Philosophy and Cognitive Science. Edited by H. ATMANSPACHER and G. J. DALENOORT. (Springer, 1994.) [pp. + + 415.] DM98.00, SFr98.00 (hbk). ISBN 3 540 57088 8. Scope: conference proceedings. Level: specialist. Introduction to the Theory of Critical Phenomena By D. I. UZUNOV 1993, £54·00 (hbk), £24·00 (pbk), pp. xx + 452. World Scientific, ISBN 981 02 0389 6. Scope: monograph. Level: postgraduate and specialist. Low-Capacity Cryogenic Refrigeration. By G. WALKER and E. R. BINGHAM. (Clarendon Press, Oxford, 1994) [pp. xv + 302.] £45.00 (hbk). ISBN 0 198 51760 2. Scope: monograph. Level: postgraduate and specialist. Mathematical Techniques By D. W. JORDAN and P. SMITH 1994, £14·95 (pbk), pp. xvi + 659. Oxford, ISBN 0 19 856267 5. Scope: textbook. Level: undergraduate. Mechanics of Solid Materials By J. LEMAITRE and J.-L. CHABOCHE 1994, £25·00, US$34·95 (pbk), pp. xxv + 556. Cambridge, ISBN 0 521 47758 1. Scope: monograph. Level: specialist. Order in Thin Organic Films By R. H. TREDGOLD (Cambridge University Press, 1994.) [pp. xii + 199.] £32.50, US$49.95 (hbk). ISBN 0 521 39484 8. Scope: monograph. Level: postgraduate and specialist. Particle Physics at the Fermi Scale Edited by Y. PANG, J. QIU and Z. QIU 1994, £70·00, US$108·00 (hbk), pp. xiii + 492. Gordon & Breach, ISBN 2 88449 108 2. Scope: symposium proceedings. Level: specialist. Plasma Physics. Basic Theory with Fusion Applications. 2nd. Edn. By. K. NISHIKAWA and M. WAKATANI. (Springer, 1994) [pp. xiii + 336.] DM80.00, SFr80.00. ISBN 3 540 56854 9. Scope: textbook. Level: postgraduate and specialist. Physics , 4th edition, Vol. 1 and Vol. 2 Extended By R. RESNICK, D. HALLIDAY and K. S. KRANE 1992, £24·95 each (pbk), pp. xi + 636 (Vol. 1), xi + 665 (Vol. 2). Wiley, ISBN0471 55917 2 (Vol. 1),0471 559180 (Vol. 2). Scope: textbook. Level: undergraduate. Properties of Narrow Gap Cadmium-Based Components Edited by P. CAPPER 1994, £165·00 (hbk), pp. xxi + 618. The Institution of Electrical Engineers, ISBN 0 85296 880 9. Scope: reference. Level: specialist. The Limits of Safety: Organizations, Accidents, and Nuclear Weapons By S. D. SAGAN 1993, US$29·95 (hbk) pp. xvi + 286. Princeton, ISBN 0 69 93221 1. Scope: text. Level: non-specialist. Transmission Electron Microscopy By L. REIMER 1993, DM98·00 (pbk), pp. xiii + 545. Springer-Verlag, ISBN 3 540 56849 2. Scope: monograph. Level: postgraduate and specialist. The Real Structure of High Tc Superconductors. Edited by V. SH. SHEKHTMAN. (Springer, 1993.) [pp. ix + 189.] £54.50 (hbk). ISBN 3 540 56559 0. Scope: multi-author review. Level: specialist. Physics Demonstrations in Electricity and Magnetism. Parts I, II, III. (Physics Curriculum and Instruction, Lateville, Minnesota, 1993.) [Run time: Part I, 30;00 min; Part II, 30:00 min; Part III, 30:00 Min.] £55.00 each, £148.00 complete set. Scope: video demonstrations. Level: school GCSE and Advanced Level; undergraduate.
Ben A. Eaton, Charles R. Knowles, I. H. Silberbrg
Journal of Petroleum Technology, Volume 19, pp 815-828; https://doi.org/10.2118/1525-pa

Abstract:
This paper presents the results of an investigation of two-phase, gas-liquid flow in horizontal pipelines. Experimental data were taken in three field-size, horizontal pipelines, two of which were constructed for this purpose. The data were obtained using water, distillate and crude oil separately as the liquid phase, and natural gas as the second phase. Experimental pressure-length traverse, liquid holdup and flow-pattern data were collected for each set of flow rates. These data were used to develop three correlations that are presented herein. The liquid-holdup values correlated with various flow parameters without regard to the existing flow pattern. The same was true for the energy-loss factors. A new flow-pattern map is presented that appears to be quite reliable, but not required for the pressure-loss calculations. The liquid-holdup correlation and the energy-loss factor correlation are used in conjunction with a two-phase flow power balance, developed during this study, to predict the pressure losses that occur during gas-liquid flow in horizontal pipelines. A recommended calculational procedure is given, as well as a statistical analysis of the results. This procedure lends itself to computer application, since several small pressure decrements are needed to calculate a pressure-length traverse. The correlations are shown graphically, but may be curve fitted with existing curve-fitting computer programs. Introduction Due to the frequent occurrence of gas-liquid flow in pipelines and the desire to accurately calculate the pressure losses that occur in these lines, two-phase flow is of considerable interest to the petroleum, chemical and nuclear industries. In the petroleum industry, gas-liquid mixtures have been transported over relatively long distances in a common line due to the advent of centralized gathering and separation systems. Long two-phase flowlines are usually accompanied by large pressure drops which influence the design of the system. Gas-lift installations are designed on the basis of known tubing pressures at the wellheads. The horizontal flowline connecting the wellhead and the separator system must be correctly sized in order to minimize the horizontal flowline pressure losses and the wellhead tubing pressure. Practically all oilwell production design involves horizontal two-phase flow in pipelines. All of the flow processes of oil and gas production must be studied simultaneously to insure good well design. Since the beginning of offshore oilfield development, long horizontal flowlines have been constructed. Because pressure losses greatly influence the performance of producing wells, a method is desired that can be used to predict such pressure losses and select optimum flowline size. Several types of gas-liquid flow exist, and many of these are discussed by Gouse. The study of pressure gradients, fluid distributions and flow patterns that occur in horizontal multiphase flow is made difficult by the great number of variables involved. The various flow regimes give rise to changing velocities of the fluid particles in all directions. These instabilities of the interface between the gas and liquid prohibit the determination of actual vector velocities of fluid particles in each phase. Also, it is practically impossible to arrive at correct sets of boundary conditions. Therefore, most investigators have concluded that a solution to the problem by the classical fluid dynamics approach, whereby the Navier-Stokes equations are formulated and solved, is far too complex. Other methods must be utilized to develop general correlations that will predict the behavior of gas-liquid horizontal flow systems. Multiphase flow studies have sought to develop a technique with which the pressure drop can be calculated. Pressure losses in two-phase, gas-liquid flow are quite different from those encountered in single-phase flow; in most cases an interface exists and the gas slips past the liquid. The interface may be smooth or have varying degrees of roughness, depending on the flow pattern. Therefore, a transfer of energy from the gaseous phase to the liquid phase may take place while energy is lost from the system through the wetting phase at the pipe wall. Such an energy transfer may be either in the form of heat exchange or of acceleration. Since each phase must flow through a smaller area than if it flowed alone, amazingly high pressure losses occur when compared to single-phase flow. Most investigators of horizontal two-phase flow phenomena have chosen to separate their experimental data into several groups of observed flow patterns or regimes. JPT P. 815ˆ
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