bluuebunny/crossref_metadata_2025_split huggingface dataset:
Millimeter‐wave metasurface lens aided phaseless characterization for quiet zone of compact antenna test range
Authors: Chen Yuqing , Yao Yuan , Zhu Lei , Wu Gengbo , Yu Junsheng , Chen Xiaodong 
Published: April 2022

AbstractThe quiet zone of compact antenna test range (CATR) is typically required as uniform as possible with a low phase deviation error. Here, we propose a novel phaseless CATR characterization method by combining a single millimeter‐wave metasurface lens‐based technique and an alternating projection algorithm. The metasurface lens provides two sets of weakly correlated amplitude‐only data to the algorithm by changing the propagation path of the pseudo‐plane wave, hence realizing the phase retrieval of the quiet zone with low complexity of measures. In addition, initial phase preprocessing is adopted to further improve the precision of phase retrieval. Furthermore, different alternating projection algorithms are compared to validate the effectiveness of the proposed method, showing the maximum phase error in the effective quiet zone reaches 0.75° at 220 GHz. In the end, the simulation results show that the proposed method can be applied in the ultra‐broadband frequency range of 120 GHz. In a nutshell, this paper provides new insights for the applications of metasurface lens in the phaseless characterization of CATR.
MaxGIRF: Image reconstruction incorporating concomitant field and gradient impulse response function effects
Authors: Lee Nam G. , Ramasawmy Rajiv , Lim Yongwan , Campbell‐Washburn Adrienne E. , Nayak Krishna S. 
Published: April 2022

PurposeTo develop and evaluate an improved strategy for compensating concomitant field effects in non‐Cartesian MRI at the time of image reconstruction.TheoryWe present a higher‐order reconstruction method, denoted as MaxGIRF, for non‐Cartesian imaging that simultaneously corrects off‐resonance, concomitant fields, and trajectory errors without requiring specialized hardware. Gradient impulse response functions are used to predict actual gradient waveforms, which are in turn used to estimate the spatiotemporally varying concomitant fields based on analytic expressions. The result, in combination with a reference field map, is an encoding matrix that incorporates a correction for all three effects.MethodsThe MaxGIRF reconstruction is applied to noiseless phantom simulations, spiral gradient‐echo imaging of an International Society for Magnetic Resonance in Medicine/National Institute of Standards and Technology phantom, and axial and sagittal multislice spiral spin‐echo imaging of a healthy volunteer at 0.55 T. The MaxGIRF reconstruction was compared against previously established concomitant field‐compensation and image‐correction methods. Reconstructed images are evaluated qualitatively and quantitatively using normalized RMS error. Finally, a low‐rank approximation of MaxGIRF is used to reduce computational burden. The accuracy of the low‐rank approximation is studied as a function of minimum rank.ResultsThe MaxGIRF reconstruction successfully mitigated blurring artifacts both in phantoms and in vivo and was effective in regions where concomitant fields counteract static off‐resonance, superior to the comparator method. A minimum rank of 8 and 30 for axial and sagittal scans, respectively, gave less than 2% error compared with the full‐rank reconstruction.ConclusionsThe MaxGIRF reconstruction simultaneously corrects off‐resonance, trajectory errors, and concomitant field effects. The impact of this method is greatest when imaging with longer readouts and/or at lower field strength.
Modified cellulose nanocrystals based on SI‐ATRP for enhancing interfacial compatibility and mechanical performance of biodegradable PLA/PBAT blend
Authors: Sun Minqi , Zhang Ling , Li Chunzhong 
Published: April 2022

AbstractTo make up for the brittleness of poly(lactic acid) (PLA), people usually introduce flexible poly(butylene adipate‐co‐terephthalate) (PBAT) which greatly reduces the strength and limits toughening effect due to unfavorable immiscibility of the blends. Herein, functionalized biodegradable cellulose nanocrystals (CNCs) were used as enhancement to simultaneously improve strength and toughness of PLA/PBAT blend. To improve the interaction between PLA and PBAT, poly(glycidyl methacrylate) (PGMA) was grafted on the surface of CNC via a surface‐initiated atom transfer radical polymerization reaction. After the addition of CNC‐PGMA30, the phase size of PLA/PBAT (70/30 wt%) reduces dramatically, showing improved interfacial compatibility between PLA and PBAT. Meanwhile, prepared PLA/PBAT/CNC1.0‐PGMA30 composite has tensile strength of 49.6 MPa and elongation at break of 268.5%, demonstrating considerably increased strength and toughness in comparison to the pure PLA/PBAT blend.
Effects of incorporating ZnO nanowires on the moisture absorption and mechanical properties of composites
Authors: Kannan Manikandanbabu , Swaminathan Gowthaman , Venkat Natarajan 
Published: April 2022

AbstractFor the first time, this study explores how the incorporation of ZnO nanowires (ZnO NW) in the interface affects moisture absorption and resultant mechanical properties of glass and carbon composites. ZnO NW were coated onto glass and carbon fabrics to modify the fiber/matrix interface in the composites. Moisture absorption, longitudinal tension, short beam shear, and mode‐I fracture tests were conducted. While the moisture absorption was found to decrease the interlaminar shear strength (ILSS) of glass composite, it was found to decrease the ILSS, tensile properties, and fracture toughness of carbon composites. The incorporation of ZnO NW was found to decrease the moisture absorption in both glass and carbon composites, increase the tensile modulus of dry and wet glass composites by ~17%, and prevent the delamination failure of wet carbon composites in tensile tests. Also, ZnO NW incorporation was found to increase the fracture toughness of all composites with a maximum of 141% improvement for dry carbon composite. Importantly, ZnO NW incorporation was believed to increase the stiffness and prevent bending failure of DCB arm in wet carbon composites. The uniqueness of this article includes demonstrating the benefits of ZnO NW to reduce the moisture absorption in composites and to reduce the extent of fiber/matrix interface degradation in wet carbon composites.
Tight bounds on the expected number of holes in random point sets
Authors: Balko Martin , Scheucher Manfred , Valtr Pavel 
Published: April 2022

AbstractFor integers and , a ‐hole in a set of points in general position in is a ‐tuple of points from in convex position such that the interior of their convex hull does not contain any point from . For a convex body of unit ‐dimensional volume, we study the expected number of ‐holes in a set of points drawn uniformly and independently at random from . We prove an asymptotically tight lower bound on by showing that, for all fixed integers and , the number is at least . For some small holes, we even determine the leading constant exactly. We improve the currently best‐known lower bound on by Reitzner and Temesvari (2019). In the plane, we show that the constant is independent of for every fixed and we compute it exactly for , improving earlier estimates by Fabila‐Monroy, Huemer, and Mitsche and by the authors.
Technical Appendix
Authors: Barrett Christopher B. , Benton Tim , Fanzo Jessica , Herrero Mario , Nelson Rebecca J. , Bageant Elizabeth , Buckler Edward , Cooper Karen , Culotta Isabella , Fan Shenggen , Gandhi Rikin , James Steven , Kahn Mark , Lawson-Lartego Laté , Liu Jiali , Marshall Quinn , Mason-D’Croz Daniel , Mathys Alexander , Mathys Cynthia , Mazariegos-Anastassiou Veronica , Miller Alesha , Misra Kamakhya , Mude Andrew , Shen Jianbo , Sibanda Lindiwe Majele , Song Claire , Steiner Roy , Thornton Philip , Wood Stephen 
Published: April 2022

AbstractAs detailed in Marshall et al. (Quinn Marshall, Jessica Fanzo, Christopher B. Barrett, Andrew D. Jones, Anna Herforth, and Rebecca McLaren, “Building a global food systems typology: A new tool for reducing complexity in food systems analysis,” Frontiers in Sustainable Food Systems, vol. 5 (November 2021): 746512), the food systemstypologies we and the Food Systems Dashboard use were developed using a method that began with a structured scoping review of the existing food systems literature.
The State of Agri-Food Systems and Agri-Food Value Chains in 2020
Authors: Barrett Christopher B. , Benton Tim , Fanzo Jessica , Herrero Mario , Nelson Rebecca J. , Bageant Elizabeth , Buckler Edward , Cooper Karen , Culotta Isabella , Fan Shenggen , Gandhi Rikin , James Steven , Kahn Mark , Lawson-Lartego Laté , Liu Jiali , Marshall Quinn , Mason-D’Croz Daniel , Mathys Alexander , Mathys Cynthia , Mazariegos-Anastassiou Veronica , Miller Alesha , Misra Kamakhya , Mude Andrew , Shen Jianbo , Sibanda Lindiwe Majele , Song Claire , Steiner Roy , Thornton Philip , Wood Stephen 
Published: April 2022

AbstractOne might reasonably invoke Dickens in describing AFSs and AVCs today: “it was the best of times, it was the worst of times.”
Envisioning Four Design Objectives for 2045–2070
Authors: Barrett Christopher B. , Benton Tim , Fanzo Jessica , Herrero Mario , Nelson Rebecca J. , Bageant Elizabeth , Buckler Edward , Cooper Karen , Culotta Isabella , Fan Shenggen , Gandhi Rikin , James Steven , Kahn Mark , Lawson-Lartego Laté , Liu Jiali , Marshall Quinn , Mason-D’Croz Daniel , Mathys Alexander , Mathys Cynthia , Mazariegos-Anastassiou Veronica , Miller Alesha , Misra Kamakhya , Mude Andrew , Shen Jianbo , Sibanda Lindiwe Majele , Song Claire , Steiner Roy , Thornton Philip , Wood Stephen 
Published: April 2022

AbstractRepeated episodes throughout history remind us that AFSs episodically undergo dramatic transformations, most of them purposeful—guided by incentives prevailing at the time—rather than purely random changes. Typically, these changes have taken decades or centuries. A major shock, like the COVID-19 pandemic, may help spark the more rapid transformation that we desperately need. Hence the value of explicitly envisioning AFS transformation to direct the transformative power unleashed by the pandemic towards desired outcomes.
A Profuse Pipeline of Promising Options
Authors: Barrett Christopher B. , Benton Tim , Fanzo Jessica , Herrero Mario , Nelson Rebecca J. , Bageant Elizabeth , Buckler Edward , Cooper Karen , Culotta Isabella , Fan Shenggen , Gandhi Rikin , James Steven , Kahn Mark , Lawson-Lartego Laté , Liu Jiali , Marshall Quinn , Mason-D’Croz Daniel , Mathys Alexander , Mathys Cynthia , Mazariegos-Anastassiou Veronica , Miller Alesha , Misra Kamakhya , Mude Andrew , Shen Jianbo , Sibanda Lindiwe Majele , Song Claire , Steiner Roy , Thornton Philip , Wood Stephen 
Published: April 2022

AbstractBecause AFSs are diverse, dynamic, and evolve continuously, they require massive continuous investment to enable ongoing discovery and adaptation merely to prevent backsliding.
Impact Pathways
Authors: Barrett Christopher B. , Benton Tim , Fanzo Jessica , Herrero Mario , Nelson Rebecca J. , Bageant Elizabeth , Buckler Edward , Cooper Karen , Culotta Isabella , Fan Shenggen , Gandhi Rikin , James Steven , Kahn Mark , Lawson-Lartego Laté , Liu Jiali , Marshall Quinn , Mason-D’Croz Daniel , Mathys Alexander , Mathys Cynthia , Mazariegos-Anastassiou Veronica , Miller Alesha , Misra Kamakhya , Mude Andrew , Shen Jianbo , Sibanda Lindiwe Majele , Song Claire , Steiner Roy , Thornton Philip , Wood Stephen 
Published: April 2022

AbstractThe complex pathways from innovation to impact mean that unintended spillover effects on non-target objectives are always likely. This generates a third reason—in addition to accelerators and complementarity in pursuit of target objectives—why socio-technical bundles are important. Herrero et al. (2020, 2021) demonstrated that food systems innovations can have mostly neutral or positive effects on the food systems SDGs (left-hand panel of Fig. 1).
Turkish Origins and Development
Authors: Weller Paul 
Published: April 2022

AbstractWeller locates Hizmet’s origins and development in Turkey, emerging interactively with Fethullah Gülen as a Muslim scholar and teacher of a dynamic expression of Islam which inspired businesspeople and students to realise their faith through initiatives of hizmet, or service. The chapter discusses how these initiatives developed from the opening of educational opportunities to pious Muslims whose horizons had been previously restricted; through the creation of dialogue initiatives that provided fora for people to engage across deep historical fissures between the religious and the secular; to engagement in work for the relief of poverty. From these three foci, which became characteristic of Hizmet initiatives throughout the world, Hizmet further grew into a network of business associations and media organisations, thereby achieving considerable reach and influence in Turkey. Following the end of the USSR, the chapter traces how Hizmet’s educational initiatives spread into formerly Soviet Turkic countries and the Western Balkans.
Hizmet in European Hijrah
Authors: Weller Paul 
Published: April 2022

AbstractThis chapter forms the descriptive core and foundation for how the book subsequently moves into a more critical and evaluative discussion of a range of key issues within Hizmet’s transitions in Europe from its first appearance until the traumatic impact of the events of July 2016 in Turkey. Together with a European overview, the chapter especially traces Hizmet’s development within each of the countries of Belgium, Denmark, France, Germany, Italy, Netherlands, Spain, Switzerland and the UK, before briefly touching on its presence and activity in a number of other Scandinavian, Eastern and Central European countries. In doing so, it especially draws upon primary research material derived from interviews with a range of key individuals in Hizmet who have been publicly associated with it in the countries concerned, while also setting these sources within the descriptive and analytical contributions of other relevant literature.
Pivotal Issues in Pivotal Times
Authors: Weller Paul 
Published: April 2022

AbstractThe chapter traces how what some see as a previously close relationship between Turkey’s ruling AKP party and Hizmet deteriorated from that of conflict over corruption charges in relation to the government; through the Gezi Park protests; and down to the events of July 2016 and their aftermath. It takes the MV Mavi Marmara incident as illustrative of the distinctive and differentiated approach to such issues taken by Fethullah Gülen compared with that of Turkish Islamists and nationalists. The profound trauma of 15 July 2016 and its aftermath is laid bare through personal interview testimonies of Hizmet asylum-seekers and others directly impacted by this, while its indirect effects upon Hizmet individuals and initiatives previously established in Europe are also discussed. Finally, Weller identifies the emergence in Europe of what he calls a “three-layered Hizmet” consisting of early migrants, a generation of more recently emerging leaders and the new arrivals post-July 2016.
New Foci for Old Questions
Authors: Weller Paul 
Published: April 2022

AbstractThe extent and depth of trauma experienced by Hizmet consequent upon the events of July 2016 and their aftermath should not be underestimated. Their impact has brought a new “layer” of Hizmet people to Europe who often bring with them cultural assumptions different to Hizmet people who grew up in Europe. Hizmet in Europe’s financial resource base and models have been challenged. However, in many other matters, the impact of July 2016 has, rather, intensified and accelerated debate around what were previously recognised issues, but which were being engaged with in a more evolutionary way. These included debates about: the extent of Hizmet’s Turkishness or otherwise; gender in transition; the relationship between charisma, structures and transparency in connection with civil society, politics and the state; relationships with other Muslims and Hizmet’s efforts to challenge terror in the name of Islam while in some quarters also being seen as terrorists.
Introduction: Embedding the Analysis of Housing Contention in the Sociopolitical Complexity of Structural Crises
Authors: Florea Ioana , Gagyi Agnes , Jacobsson Kerstin 
Published: April 2022

AbstractThe chapter introduces the main objectives of the book: (1) to develop an analytical approach able to account for the structural and ideological complexity of contemporary housing struggles, and (2) to illustrate the practical gains of this approach by a comparative study of housing contention in two capital cities in Europe, Budapest and Bucharest. The chapter situates the book in the context of current debates on housing mobilization, arguing that studies of the post-2008 housing contention wave have been overly focused on politically progressive movements in the West. However, a closer look reveals a higher ideological complexity of housing contention: mobilizations by different constituencies and with different agendas, sometimes occupying different ends of the ideological spectrum and seeing a continuously changing landscape of alliances and oppositions. The structural field of contention approach proposed is aimed to account for these complexities based on a multi-actor, contextually embedded approach to movement formation.
The Structural Field of Contention Approach
Authors: Florea Ioana , Gagyi Agnes , Jacobsson Kerstin 
Published: April 2022

AbstractThe chapter presents the analytical approach developed in this book, conceptualized as a ‘structural field of contention approach.’ We first discuss the benefits of existing field approaches in the study of social mobilization, as well as their limitations. Deriving inspiration from Nick Crossley’s notion of social movements as ‘fields of contention,’ we then elaborate our own analytical approach, which, more than Crossley’s, stresses the structural factors that formulate the conditions of group formation and struggle. Structural factors are conceived as elements of the field of contention which both produce the conflicts around which contention arises and influence relationship-making among actors. The chapter proposes an approach which can conceptualize both the antagonisms and solidarities in housing mobilization, as well as the parallel but ideologically polarized mobilizations of different groups in the same social-structural context. The approach developed is intended to capture and theorize such complexity of contemporary housing mobilizations.
Housing Contention in Budapest
Authors: Florea Ioana , Gagyi Agnes , Jacobsson Kerstin 
Published: April 2022

AbstractThis chapter traces housing-related tensions and mobilizations across Hungary’s regime change and transition in the 1990s, the debt-driven growth of the 2000s, and the new national conservative hegemony since 2010. It identifies two main areas where housing tensions manifest: housing poverty at the bottom of the housing hierarchy, and the hardships of housing access for low- to middle-income groups. These tensions came to be expressed politically in various ways across different periods and political regimes. Homelessness and social housing were addressed by different coalitions between affected groups, right, liberal, and left professionals, and lower-middle class allies, while other aspects of housing poverty remained politically less visible. The problem of low- to middle-income households’ housing access came to be expressed around maintenance problems during the regime change, and then through the parallel politicization of accessible rentals as an alternative to home-buying, and the debt problem created by mortgage lending.
Form factors and spectral densities from Lightcone Conformal Truncation
Authors: Chen Hongbin , Fitzpatrick A. Liam , Karateev Denis 
Published: April 2022

Abstract
We use the method of Lightcone Conformal Truncation (LCT) to obtain form factors and spectral densities of local operators 𝒪 in ϕ4 theory in two dimensions. We show how to use the Hamiltonian eigenstates from LCT to obtain form factors that are matrix elements of a local operator 𝒪 between single-particle bra and ket states, and we develop methods that significantly reduce errors resulting from the finite truncation of the Hilbert space. We extrapolate these form factors as a function of momentum to the regime where, by crossing symmetry, they are form factors of 𝒪 between the vacuum and a two-particle asymptotic scattering state. We also compute the momentum-space time-ordered two-point functions of local operators in LCT. These converge quickly at momenta away from branch cuts, allowing us to indirectly obtain the time-ordered correlator and the spectral density at the branch cuts. We focus on the case where the local operator 𝒪 is the trace Θ of the stress tensor.
Boundary theories of critical matchgate tensor networks
Authors: Jahn A. , Gluza M. , Verhoeven C. , Singh S. , Eisert J. 
Published: April 2022

Abstract
Key aspects of the AdS/CFT correspondence can be captured in terms of tensor network models on hyperbolic lattices. For tensors fulfilling the matchgate constraint, these have previously been shown to produce disordered boundary states whose site-averaged ground state properties match the translation-invariant critical Ising model. In this work, we substantially sharpen this relationship by deriving disordered local Hamiltonians generalizing the critical Ising model whose ground and low-energy excited states are accurately represented by the matchgate ansatz without any averaging. We show that these Hamiltonians exhibit multi-scale quasiperiodic symmetries captured by an analytical toy model based on layers of the hyperbolic lattice, breaking the conformal symmetries of the critical Ising model in a controlled manner. We provide a direct identification of correlation functions of ground and low-energy excited states between the disordered and translation-invariant models and give numerical evidence that the former approaches the latter in the large bond dimension limit. This establishes tensor networks on regular hyperbolic tilings as an effective tool for the study of conformal field theories. Furthermore, our numerical probes of the bulk parameters corresponding to boundary excited states constitute a first step towards a tensor network bulk-boundary dictionary between regular hyperbolic geometries and critical boundary states.
A path integral for the chiral-form partition function
Authors: Andriolo E. , Lambert N. , Orchard T. , Papageorgakis C. 
Published: April 2022

Abstract
Starting from the recent action proposed by Sen [1, 2], we evaluate the partition function of the compact chiral boson on a two-dimensional torus using a path-integral formulation. Crucially, we use a Wick-rotation procedure obtained from a complex deformation of the physical spacetime metric. This directly reproduces the expected result including general characteristics for the theta functions. We also present results for the chiral 2-form potential in six dimensions which can be readily extended to 4k+2 dimensions.