Relevant bibliographies by topics / Space-times

Academic literature on the topic 'Space-times'

Author: Grafiati
Published: 4 June 2021
Last updated: 29 January 2023

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Journal articles on the topic "Space-times"

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Sonego, Sebastiano. "Ultrastatic space-times." Journal of Mathematical Physics 51, no. 9 (September 2010): 092502. http://dx.doi.org/10.1063/1.3485599.

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Placek, Tomasz, and Thomas Müller. "Branching space-times." Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics 38, no. 3 (September 2007): 590–92. http://dx.doi.org/10.1016/j.shpsb.2007.06.001.

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ELLIS, GEORGE F. R. "THE SPACE OF COSMOLOGICAL SPACE–TIMES." Journal of Hyperbolic Differential Equations 02, no. 02 (June 2005): 331–79. http://dx.doi.org/10.1142/s0219891605000476.

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I first focus on how to best describe the space of cosmological space–times and what its essential properties are and some comments on the dynamical behavior revealed by studies that will be described in more detail by John Wainwright. I will then relate this both to observations and to anthropic issues (i.e. the possible existence of observers). This space includes some viable singularity free solutions which will be briefly described, thus posing the issue of the tension between very special initial conditions and the existence of initial singularities. I will conclude with remarks on the issue of realized infinities in this context and the concept of multiverses.
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An, Xinliang, and Willie Wai Yeung Wong. "Warped product space-times." Classical and Quantum Gravity 35, no. 2 (December 19, 2017): 025011. http://dx.doi.org/10.1088/1361-6382/aa8af7.

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Ramos, M. P. M., E. G. L. R. Vaz, and J. Carot. "Double warped space–times." Journal of Mathematical Physics 44, no. 10 (2003): 4839. http://dx.doi.org/10.1063/1.1605496.

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Haesen, Stefan, and Leopold Verstraelen. "Ideally embedded space–times." Journal of Mathematical Physics 45, no. 4 (April 2004): 1497–510. http://dx.doi.org/10.1063/1.1668333.

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Lamoreaux, Steve K. "Testing times in space." Nature 416, no. 6883 (April 2002): 803–4. http://dx.doi.org/10.1038/416803a.

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Gen, Uchida, and Tetsuya Shiromizu. "Asymptotically Schwarzschild space–times." Journal of Mathematical Physics 40, no. 4 (April 1999): 2021–31. http://dx.doi.org/10.1063/1.532848.

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Hall, G. S., T. Morgan, and Z. Perj�s. "Three-dimensional space-times." General Relativity and Gravitation 19, no. 11 (November 1987): 1137–47. http://dx.doi.org/10.1007/bf00759150.

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Kim, Jong‐Chul, and Jin‐Hwan Kim. "Totally vicious space‐times." Journal of Mathematical Physics 34, no. 6 (June 1993): 2435–39. http://dx.doi.org/10.1063/1.530128.

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Dissertations / Theses on the topic "Space-times"

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Melas, Evangelos. "Aspects of asymptotically flat space-times." Thesis, Queen Mary, University of London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.398020.

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Ambrus, Victor E. "Dirac fermions on rotating space-times." Thesis, University of Sheffield, 2014. http://etheses.whiterose.ac.uk/7527/.

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Quantum states of Dirac fermions at zero or finite temperature are investigated using the point-splitting method in Minkowski and anti-de Sitter space-times undergoing rotation about a fixed axis. In the Minkowski case, analytic expressions presented for the thermal expectation values (t.e.v.s) of the fermion condensate, parity violating neutrino current and stress-energy tensor show that thermal states diverge as the speed of light surface (SOL) is approached. The divergence is cured by enclosing the rotating system inside a cylinder located on or inside the SOL, on which spectral and MIT bag boundary conditions are considered. For anti-de Sitter space-time, renormalised vacuum expectation values are calculated using the Hadamard and Schwinger-de Witt methods. An analytic expression for the bi-spinor of parallel transport is presented, with which some analytic expressions for the t.e.v.s of the fermion condensate and stress-energy tensor are obtained. Rotating states are investigated and it is found that for small angular velocities Ω of the rotation, there is no SOL and the thermal states are regular everywhere on the space-time. However, if Ω is larger than the inverse radius of curvature of adS, an SOL forms and t.e.v.s diverge as inverse powers of the distance to it.
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Björnsson, Jonas. "Strings, Branes and Non-trivial Space-times." Doctoral thesis, Karlstad University, Faculty of Technology and Science, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-1619.

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This thesis deals with different aspects of string and /p/-brane theories. One of the motivations for string theory is to unify the forces in nature and produce a quantum theory of gravity. /p/-branes and related objects arise in string theory and are related to a non-perturbative definition of the theory. The results of this thesis might help in understanding string theory better. The first part of the thesis introduces and discusses relevant topics for the second part of the thesis which consists of five papers.

In the three first papers we develop and treat a perturbative approach to relativistic /p/-branes around stretched geometries. The unperturbed theory is described by a string- or particle-like theory. The theory is solved, within perturbation theory, by constructing successive canonical transformations which map the theory to the unperturbed one order by order. The result is used to define a quantum theory which requires for consistency d = 25 + p dimensions for the bosonic /p/-branes and d = 11 for the supermembrane. This is one of the first quantum results for extended objects beyond string theory and is a confirmation of the expectation of an eleven-dimensional quantum membrane.

The two last papers deal with a gauged WZNW-approach to strings moving on non-trivial space-times. The groups used in the formulation of these models are connected to Hermitian symmetric spaces of non-compact type. We have found that the GKO-construction does not yield a unitary spectrum. We will show that there exists, however, a different approach, the BRST approach, which gives unitarity under certain conditions. This is the first example of a difference between the GKO- and BRST construction. This is one of the first proofs of unitarity of a string theory in a non-trivial non-compact space-time. Furthermore, new critical string theories in dimensions less then 26 or 10 is found for the bosonic and supersymmetric string, respectively.

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Shabbir, Ghulam. "Curvature and projective symmetries in space-times." Thesis, University of Aberdeen, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364690.

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In this thesis a number of problems concerning proper curvature collineations, proper Weyl collineations and projective vector fields will be considered. The work on the above areas can be summarised as: (i) A study of proper curvature collineations in plane symmetric static, spherically symmetric static and Bianchi type I spacetimes will be presented by considering the rank of their 6 x 6 Riemann tensors and using a theorem which eliminates those space-times where proper curvature collineations can not exist; (ii) A study of proper Weyl collineations is given by using the algebraic classification and associated rank of the Weyl tensor and using a theorem similar to that used in (i); (iii) A technique is developed to study projective vector fields in the Friedmann Robertson-Walker models and plane symmetric static spacetimes; (iv) The situations when conformally flat spacetimes admit proper curvature collineations are fully explored.
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Del, Bonifro Francesca. "Geodesics motion in fuzzy black hole space-times." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/13512/.

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Classical General Relativity predicts the existence of space-times with non-trivial casual structures known as Black Holes. A classical black hole could form by the gravitational collapse of a compact object, which should end into a singularity covered by a (sharply defined) horizon, with a size equal to the gravitational radius of the matter source. In a quantum theory, the matter source is described by a quantum state, and one can correspondingly describe its gravitational radius by means of a Horizon Wave-Function. The resulting space-time is therefore expected to be "fuzzy", and so will be the geodesic motion of test particles. Orbits of massive particles as well as trajectories of light rays around such fuzzy gravitational sources are here analysed in details using both analytical approximations and numerical calculations. The uncertainty in the time of radial free fall and the effects on the out-going radiation emitted by the collapsing matter will also be presented.
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Mena, Filipe Artur Pacheco Neves Carteado. "Inhomogeneous and anisotropic space times in general relativity." Thesis, Queen Mary, University of London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.252193.

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Wilson, Jonathan Peter. "Regularity of axisymmetric space-times in general relativity." Thesis, University of Southampton, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243657.

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Hobe, Stephan. "Space law: necessary changes in times of globalisation." Thesis, National Aviation University, 2021. https://er.nau.edu.ua/handle/NAU/48791.

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In 2020, we have celebrated the 60th year of space law making. Around 1959/1960 the work of the United Nations Committee on the Peaceful Uses of Outer Space and in particular its Legal Subcommittee started with a view to implement international space law. As we will show in this lecture there were different phases of space law making that all had their distinct feature.Characteristic for the first period of space law making was, on the one hand, that there was always a military overtone to the use of outer space that played a preeminent role.
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Millner, Anthony. "Noncommutative phenomena in flat and curved space-times." Master's thesis, University of Cape Town, 2004. http://hdl.handle.net/11427/4910.

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Includes bibliographical references (leaves 88-92).
This thesis aims to explore several facets of noncommutative geometry which arise in physics. In particular, our focus will be on string-inspired noncommutativity, and we will at all times try to justify the noncommutative models we study from a stringy perspective.
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Khan, Muhsan A. "Holonomy and projective symmetry in general relativity." Thesis, University of Aberdeen, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369628.

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A study of the holonomy group of space-time is undertaken and related to the Segre and Petrov types of then Weyl and E-tensors respectively. Attention is then focused on the E-tensor, and a theorem is proved which states that any space-time M can be disjointly decomposed into open sets on which the Segre type of the E-tensor is constant, the union of which if dense in M. This theorem is then applied to prove a similar theorem for the Ricci tensor using the principal null directions of the E-tensor. Finally, a study of proper projective symmetry in null and non-null Einstein-Maxwell and static, spherically symmetric space-times is performed. A theorem is proved which states that no proper projective symmetry is possible in any null Einstein-Maxwell space-times. This result is then extended to the non-null case under some general restrictions. The static, spherically symmetric space-times are then considered, and those admitting proper projective symmetry are completely determined. The proper projective vector fields are also explicitly calculated.
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Books on the topic "Space-times"

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Times space. [Place of publication not identified]: TIMES Books, 2002.

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M, Williams Ruth, ed. Flat and curved space-times. Oxford: Clarendon, 1988.

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Ellis, George F. R., and George Francis Rayner Ellis. Flat and curved space-times. Oxford [England]: Clarendon Press, 1988.

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(Firm), Times Books, ed. The Times Britain from space. London: Times Books, 2000.

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Ellis, George F. R., and George Francis Rayner Ellis. Flat and curved space-times. 2nd ed. Oxford: Oxford University Press, 2000.

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M, Williams R., ed. Flat and curved space-times. Oxford: Clarendon, 2000.

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(Donato), Bini D., ed. Classical measurements in curved space-times. Cambridge: Cambridge University Press, 2010.

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Williams, Ruth M. An introduction to curved space-times. Geneva: Organisation européenne pour la recherche nucléaire, 1991.

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Griffiths, J. B. Exact space-times in Einstein's general relativity. Cambridge: Cambridge University Press, 2009.

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1941-, Allen John Logan, Dasch E. Julius, and Gough Barry M, eds. Explorers: From ancient times to the space age. New York: Macmillan Reference USA, 1998.

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Book chapters on the topic "Space-times"

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Ashtekar, Abhay. "Quantum Space-Times." In Minkowski Spacetime: A Hundred Years Later, 163–96. Dordrecht: Springer Netherlands, 2009. http://dx.doi.org/10.1007/978-90-481-3475-5_7.

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Barrow, John D. "Chaotic space-times." In The Physics of Phase Space Nonlinear Dynamics and Chaos Geometric Quantization, and Wigner Function, 18–21. Berlin, Heidelberg: Springer Berlin Heidelberg, 1987. http://dx.doi.org/10.1007/3-540-17894-5_308.

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Falls, Kevin. "Black Hole Space-Times." In Asymptotic Safety and Black Holes, 73–110. Cham: Springer International Publishing, 2013. http://dx.doi.org/10.1007/978-3-319-01294-0_4.

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Maia, M. D. "Geometry of Space–Times." In Geometry of the Fundamental Interactions, 57–71. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-8273-5_5.

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Placek, Tomasz. "On Belnap’s Branching Space-Times." In Philosophy and Logic in Search of the Polish Tradition, 77–92. Dordrecht: Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-017-0249-2_7.

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Belnap, Nuel. "Norms in Branching Space-Times." In Lecture Notes in Computer Science, 1–2. Berlin, Heidelberg: Springer Berlin Heidelberg, 2008. http://dx.doi.org/10.1007/978-3-540-70525-3_1.

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Lee, Gini. "Public space for changing times." In Subverting Consumerism, 125–43. Abingdon, Oxon ; New York, NY : Routledge, 2018.: Routledge, 2018. http://dx.doi.org/10.4324/9781315641812-8.

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Sanchez, N. "Quantum Strings in Curved Space Times." In NATO ASI Series, 265–315. Boston, MA: Springer US, 1990. http://dx.doi.org/10.1007/978-1-4615-3814-1_10.

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Sämann, Clemens, and Roland Steinbauer. "Geodesic Completeness of Generalized Space-times." In Pseudo-Differential Operators and Generalized Functions, 243–53. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-14618-8_17.

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Martín-Prats, M., and José M. M. Senovilla. "Matching of stationary axisymmetric space-times." In Rotating Objects and Relativistic Physics, 136–40. Berlin, Heidelberg: Springer Berlin Heidelberg, 1993. http://dx.doi.org/10.1007/3-540-57364-x_209.

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Conference papers on the topic "Space-times"

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Van den Bergh, N. "Homogeneous killing spinor space-times." In TOWARDS NEW PARADIGMS: PROCEEDING OF THE SPANISH RELATIVITY MEETING 2011. AIP, 2012. http://dx.doi.org/10.1063/1.4734478.

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Morcillo Pallares, Ana. "Times Square, Times Out! A Speculative Approach on Public Space Practice." In 2018 ACSA International Conference. ACSA Press, 2018. http://dx.doi.org/10.35483/acsa.intl.2018.31.

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480,000 tourists and locals walk through Times Square daily.1 A global destination oversaturated by millions of visitors around the world, a space of discrepancy between locals and administrators, shared by spectators and sanitation workers, entertainment and consumerism, filled by families, tourists, security cameras and performers; Times Square represents a case of study where public space is tested, produced and denied in everyday and extraordinary ways. The Square’s dense and diverse pedestrian activity offers a unique design challenge to explore more than ever public space practices addressing the pros and cons of the changing politics and city protocols, citizen’s demands and the principles of what makes spaces public, what it stands for, and how to provide an environment for interaction.
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CRISCIENZO, R. DI, S. A. HAYWARD, M. NADALINI, L. VANZO, and S. ZERBINI. "HORIZON THERMODYNAMICS IN FRW SPACE-TIMES." In Proceedings of the MG12 Meeting on General Relativity. WORLD SCIENTIFIC, 2012. http://dx.doi.org/10.1142/9789814374552_0153.

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LÜBBE, CHRISTIAN. "ON DE SITTER-LIKE SPACE-TIMES." In Proceedings of the MG12 Meeting on General Relativity. WORLD SCIENTIFIC, 2012. http://dx.doi.org/10.1142/9789814374552_0318.

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SHABBIR, GHULAM. "PROPER PROJECTIVE SYMMETRIES IN SPACE-TIMES." In Proceedings of the 12th Regional Conference. WORLD SCIENTIFIC, 2007. http://dx.doi.org/10.1142/9789812770523_0040.

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ROMERO, C., and F. DAHIA. "ANOMALOUS ACCELERATION AND FIVE-DIMENSIONAL SPACE-TIMES." In Proceedings of the MG10 Meeting held at Brazilian Center for Research in Physics (CBPF). World Scientific Publishing Company, 2006. http://dx.doi.org/10.1142/9789812704030_0133.

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Venkateswaran, Sriram, and Upamanyu Madhow. "Space-time localization using times of arrival." In 2011 49th Annual Allerton Conference on Communication, Control, and Computing (Allerton). IEEE, 2011. http://dx.doi.org/10.1109/allerton.2011.6120351.

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Allen, Jr., Hubert A. "Failure Times in Space: A Statistician's Perspective." In Eighth International Conference on Engineering, Construction, Operation, and Business In Space; Fifth International Conference and Exposition and Demonstration on Robotics for Challenging Situations and Environments. Reston, VA: American Society of Civil Engineers, 2002. http://dx.doi.org/10.1061/40625(203)7.

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Fontana, Giorgio. "The Four Space-times Model of Reality." In SPACE TECHNOLOGY AND APPLICATIONS INT.FORUM-STAIF 2005: Conf.Thermophys in Micrograv;Conf Comm/Civil Next Gen.Space Transp; 22nd Symp Space Nucl.Powr Propuls.;Conf.Human/Robotic Techn.Nat'l Vision Space Expl.; 3rd Symp Space Colon.; 2nd Symp.New Frontiers. AIP, 2005. http://dx.doi.org/10.1063/1.1867271.

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Pincay, Jhonny, Alvin Mensah, Edy Portmann, and Luis Terán. "Forecasting Travel Times with Space Partitioning Methods." In 6th International Conference on Geographical Information Systems Theory, Applications and Management. SCITEPRESS - Science and Technology Publications, 2020. http://dx.doi.org/10.5220/0009324601510159.

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Reports on the topic "Space-times"

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McFarlane, Karis J. 2nd Annual Report: Tropical Forest Response To A Drier Future: Turnover Times Of Soil Organic Matter, Roots, Respired CO2, And CH4 Across Moisture Gradients In Time And Space. Office of Scientific and Technical Information (OSTI), June 2018. http://dx.doi.org/10.2172/1466169.

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McFarlane, Karis J. Terrestrial Ecosystem Science 2017 ECRP Annual Report: Tropical Forest Response to a Drier Future: Turnover Times of Soil Organic Matter, Roots, Respired CO2, and CH4 Across Moisture Gradients in Time and Space. Office of Scientific and Technical Information (OSTI), May 2017. http://dx.doi.org/10.2172/1363856.

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Sohane, Nidhi, Ruchika Lall, Ashwatha Chandran, Rasha Hasan Lala, Namrata Kapoor, and Harshal Deepak Gajjar. Home as Workplace: A Spatial Reading of Work-Homes. Indian Institute for Human Settlements, 2021. http://dx.doi.org/10.24943/hwsrwh10.2021.

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When home serves as workplace, the interface of domestic and productive spheres has spatial and social effects on various users of the space, scaling at times to the neighbourhood and the city. This study looks at all the ways in which home aids work — spatially and infrastructurally — and illustrates the role of various factors and actors in engaging with and shaping the work-home boundary. Work-homes in the Global South often engage transversally with formal planning. Users of work-homes exercise their agency in complex ways to maneuver the work-home boundary, often making post-facto modifications to the work-home. The study collates a repository of spatial and temporal innovation strategies devised by users to balance domestic and productive spheres in their homes, as a site to derive lessons for planning, housing policy and architecture. It investigates the role of the state in spatially enabling or limiting work-homes, and using the Indian context as an illustrative example, suggests enabling frameworks in planning that address the spatial particularities of work-homes
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Abed, Dana, Rihab Sawaya, and Nadim Tabbal. Analyzing Voter Turnout in Lebanon: Political Change in Times of Crisis. Oxfam, April 2022. http://dx.doi.org/10.21201/2022.8823.

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In May 2022, Lebanon is hosting its first parliamentary elections since the popular uprising of October 2019, when massive protests took place to denounce the current ruling elites. This research looks at voter turnout and behavior on the eve of the elections and examines the will for political change. It argues that in the current Lebanese context, there needs to be further political awareness-raising, and campaigns should be more inclusive of women and the queer community. Independent campaigns should focus on developing strong governing capacities that voters can trust, and create further space for civic and political engagement on the local and national levels.
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Warrick, Arthur W., Gideon Oron, Mary M. Poulton, Rony Wallach, and Alex Furman. Multi-Dimensional Infiltration and Distribution of Water of Different Qualities and Solutes Related Through Artificial Neural Networks. United States Department of Agriculture, January 2009. http://dx.doi.org/10.32747/2009.7695865.bard.

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The project exploits the use of Artificial Neural Networks (ANN) to describe infiltration, water, and solute distribution in the soil during irrigation. It provides a method of simulating water and solute movement in the subsurface which, in principle, is different and has some advantages over the more common approach of numerical modeling of flow and transport equations. The five objectives were (i) Numerically develop a database for the prediction of water and solute distribution for irrigation; (ii) Develop predictive models using ANN; (iii) Develop an experimental (laboratory) database of water distribution with time; within a transparent flow cell by high resolution CCD video camera; (iv) Conduct field studies to provide basic data for developing and testing the ANN; and (v) Investigate the inclusion of water quality [salinity and organic matter (OM)] in an ANN model used for predicting infiltration and subsurface water distribution. A major accomplishment was the successful use of Moment Analysis (MA) to characterize “plumes of water” applied by various types of irrigation (including drip and gravity sources). The general idea is to describe the subsurface water patterns statistically in terms of only a few (often 3) parameters which can then be predicted by the ANN. It was shown that ellipses (in two dimensions) or ellipsoids (in three dimensions) can be depicted about the center of the plume. Any fraction of water added can be related to a ‘‘probability’’ curve relating the size of the ellipse (or ellipsoid) that contains that amount of water. The initial test of an ANN to predict the moments (and hence the water plume) was with numerically generated data for infiltration from surface and subsurface drip line and point sources in three contrasting soils. The underlying dataset consisted of 1,684,500 vectors (5 soils×5 discharge rates×3 initial conditions×1,123 nodes×20 print times) where each vector had eleven elements consisting of initial water content, hydraulic properties of the soil, flow rate, time and space coordinates. The output is an estimate of subsurface water distribution for essentially any soil property, initial condition or flow rate from a drip source. Following the formal development of the ANN, we have prepared a “user-friendly” version in a spreadsheet environment (in “Excel”). The input data are selected from appropriate values and the output is instantaneous resulting in a picture of the resulting water plume. The MA has also proven valuable, on its own merit, in the description of the flow in soil under laboratory conditions for both wettable and repellant soils. This includes non-Darcian flow examples and redistribution and well as infiltration. Field experiments were conducted in different agricultural fields and various water qualities in Israel. The obtained results will be the basis for the further ANN models development. Regions of high repellence were identified primarily under the canopy of various orchard crops, including citrus and persimmons. Also, increasing OM in the applied water lead to greater repellency. Major scientific implications are that the ANN offers an alternative to conventional flow and transport modeling and that MA is a powerful technique for describing the subsurface water distributions for normal (wettable) and repellant soil. Implications of the field measurements point to the special role of OM in affecting wettability, both from the irrigation water and from soil accumulation below canopies. Implications for agriculture are that a modified approach for drip system design should be adopted for open area crops and orchards, and taking into account the OM components both in the soil and in the applied waters.
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DESIGN OF THE DEPLOYABLE-FOLDABLE ACTUATOR AND VIBRATION CONTROL DEVICE BASED ON THE SHAPE MEMORY ALLOYS WITH A TWO-WAY EFFECT. The Hong Kong Institute of Steel Construction, August 2022. http://dx.doi.org/10.18057/icass2020.p.306.

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The paper aims at the design method of the space deployable-foldable actuator and vibration control device, and the selected material is the shape memory alloy. These devices can repeatedly adjust the deploy and fold states by changing the temperature, and also present a large energy dissipation to keep the stability of the structures in the vibration control. It can be observed that the fabricated two-way shape memory alloy actuator can present steady fold-deploy procedures more than five times, in which the recoverable rate is higher than 95.83%, and the required time in the complete deploying process is 15 s. Meanwhile, the vibration control device based on the shape memory alloys also gives an excellent performance, the lightweight device is only 315 g, and the vibration in the vertical direction can be limited to the millimeter-level (0.917 mm), it can also endure the repeated loadings in the applications and keep a good operating condition.
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