bluuebunny/crossref_metadata_2025_split huggingface dataset:
MOND-like behavior in the Dirac–Milne universe
Authors: Chardin Gabriel , Dubois Yohan , Manfredi Giovanni , Miller Bruce , Stahl Clément 
Published: June 2021

Aims.Observational data show that the observed luminous matter is not sufficient to explain several features of the present universe, from gravitational structure formation to the rotational velocities in galaxies and clusters. The mainstream explanation is that the missing mass, although gravitationally active, interacts very weakly with ordinary matter. Competing explanations involve changing the laws of gravity at low accelerations, as in MOdified Newtonian Dynamics (MOND). Here, we suggest that the Dirac-Milne cosmology, a matter-antimatter symmetric cosmology where the two components repel each other, is capable of accounting for such an apparent modification of the Newtonian law, without invoking dark matter.Methods.Using a simple analytical approximation and 1D and 3D simulations, we study rotation curves and virial velocities and compare the mass observed in the simulations to the mass derived assuming Newtonian gravity. Using a modified version of theRAMSEScode, we study the Faber-Jackson scaling relation and the intensity of the additional gravitational field created by antimatter clouds.Results.We show that, in the Dirac-Milne universe, rotation curves are generically flat beyond a characteristic distance of ≈2.5 virial radii, and that the Tully-Fisher and Faber-Jackson scaling relations with an exponent ≈3 are satisfied. We show that the mass derived from the rotation curves assuming Newtonian gravity is systematically overestimated compared to the mass really present. In addition, the Dirac-Milne universe, featuring a polarization between its matter and antimatter components, presents a behavior similar to that of MOND, characterized by an additional surface gravity compared to the Newtonian case. We show that in the Dirac-Milne universe, at the present epoch, the intensity of the additional gravitational fieldgamdue to the presence of clouds of antimatter is on the order of a few 10−11m s−2, similar to the characteristic acceleration of MOND. We study the evolution of this additional accelerationgamand show that it depends on the redshift, and it is therefore not a fundamental constant.Conclusions.Combined with its known concordance properties on the SNIa luminosity distance, age, nucleosynthesis, and structure formation, the Dirac-Milne cosmology may then represent an interesting alternative to the standard cosmological model ΛCDM, MOND, and other scenarios for explaining the dark matter (or missing gravity) and dark energy conundrum.
Semiconducting character of LaN: Magnitude of the bandgap and origin of the electrical conductivity
Authors: Deng Zihao , Kioupakis Emmanouil 
Published: June 2021

Lanthanum nitride (LaN) has attracted research interest in catalysis due to its ability to activate the triple bonds of N2 molecules, enabling efficient and cost-effective synthesis of ammonia from N2 gas. While exciting progress has been made to use LaN in functional applications, the electronic character of LaN (metallic, semi-metallic, or semiconducting) and magnitude of its bandgap have so far not been conclusively determined. Here, we investigate the electronic properties of LaN with hybrid density functional theory calculations. In contrast to previous claims that LaN is semi-metallic, our calculations show that LaN is a direct-bandgap semiconductor with a bandgap value of 0.62 eV at the X point of the Brillouin zone. The dispersive character of the bands near the band edges leads to light electron and hole effective masses, making LaN promising for electronic and optoelectronic applications. Our calculations also reveal that nitrogen vacancies and substitutional oxygen atoms are two unintentional shallow donors with low formation energies that can explain the origin of the previously reported electrical conductivity. Our calculations clarify the semiconducting nature of LaN and reveal candidate unintentional point defects that are likely responsible for its measured electrical conductivity.
Gravitational SIMPs
Authors: Barman Basabendu , Bernal Nicolás 
Published: June 2021

Abstract
We study the impact of thermalization and number-changing processes in the dark sector on the yield of gravitationally produced dark matter (DM).
We take into account the DM production through the s-channel exchange of a massless graviton both from the scattering of inflatons during the reheating era, and from the Standard Model bath via the UV freeze-in mechanism. By considering the DM to be a scalar, a fermion, and a vector boson we show, in a model-independent way, that DM self-interaction gives rise to a larger viable parameter space by allowing lower reheating temperature to be compatible with Planck observed relic abundance. As an example, we also discuss our findings in the context of the ℤ2-symmetric scalar singlet DM model.
Ultralocality and slow contraction
Authors: Ijjas Anna , Sullivan Andrew P. , Pretorius Frans , Steinhardt Paul J. , Cook William G. 
Published: June 2021

Abstract
We study the detailed process by which slow contraction smooths and flattens the universe using an improved numerical relativity code that accepts initial conditions with non-perturbative
deviations from homogeneity and isotropy along two independent spatial directions.
Contrary to common descriptions of the early universe,
we find that the geometry first rapidly converges to an inhomogeneous, spatially-curved and anisotropic ultralocal state in which all spatial
gradient contributions to the equations of motion decrease as an exponential in time to negligible values. This is followed by a second stage in which the geometry converges to a homogeneous, spatially flat and isotropic spacetime. In particular, the decay appears to follow the same history whether the entire spacetime or only parts of it are smoothed by the end of slow contraction.
Modeling of program-target organization and management of competitiveness of territorial reproduction systems in construction
Authors: Krygina A M , Krygina N M , Shchenyatskaya M A , Oberemok M I 
Published: June 2021

Abstract
Abstract.This study examines modern theoretical and methodological approaches to solving the problem of program-target organization and management of meso-competitiveness in construction as a prerequisite for effective practical implementation of transformational development according to key monitoring indicators such as productivity, organizational and technical reliability. Taking into account the inevitability of the involvement of territorial construction complexes in the reproduction processes as a meso-economic competitive territorial-reproduction construction system, the article substantiates the need to develop special program-target methods for regulating these processes. It shows the expediency of combining the competitiveness, productivity of territorial construction complexes and reproduction processes in construction by the program-target method. The adopted programs should essentially become mortgage and investment programs for long-term management of the reproduction of territorial-portfolio land and property complexes in various industries and infrastructures. The study presents the efficiency of using consortium-type structures to implement the idea of forming high-performance cluster systems in construction at regional and inter-regional levels. Mortgage and investment programs for sustainable development of residential construction should become a tool for managing the process of transformational regulation of competitiveness from its local level to the interregional and international levels with a clear system organization.
The problems of historical settlements’ enhancement and the possible solutions
Authors: Blagovidova N G , Iudina N V 
Published: June 2021

Abstract
The paper deals with the problems of historical settlements, which lead to the loss of their status and critical violations of the historical environment. The author analyzes the problems of historical settlements and their particularly vulnerable type – small formations – including social, political, economic, and scientific research. The author points out the need for complex innovative approaches that ensure not only the material restoration, but also the functional development of the historical environment, the introduction of new functions. The tools of working with the historical urban environment and its active functional inclusion in the modern discourse, models of increasing the value characteristics of urban objects, as well as the principles of implementing local potentials, which are laid in the basis of a holistic methodology, are considered. A strategy is proposed that solves the extremely acute issue of the urban significance of historical and cultural monuments on the basis of management tools and spatial planning, and tactical steps for its implementation are highlighted. The methodology obtained as a result of the study can be used as a basis for a national program aimed at developing and strengthening the social and economic role of small historical cities in the country’s settlement system.
Capillary-absorbed moisture transfer in a multiphase soil medium considering the load potential
Authors: Tedeev T R 
Published: June 2021

Abstract
The work presents an analytical solution to the equation of moisture permeability of structural varieties of capillary-absorbed moisture in a multiphase soil system with incomplete water saturation considering the influence of load potential. Researches were carried out and the influence of external load on the moisture profile in a multiphase system, the rate of moisture transfer of a discontinuous flow in general, and the rate of moisture propagation of the wetting boundaries have been shown. For a comparative analysis of the indicators of moisture transfer, functional relationships between the potential and pressure of the structural varieties of capillary-absorbed ground moisture are presented: capillary-gravity, proper-capillary and capillary-osmotic components of ground moisture. In the interval of incomplete water saturation, an attempt was made to create the foundations of capillary moisture transfer in the soil environment considering both the external distributed load and the own weight of the soil.
Features of wooden buildings in Tomsk
Authors: Babinovich N U , Sitnikova E V 
Published: June 2021

Abstract
The article is devoted to analysis and systematization of classical wooden buildings in Tomsk. The relevance of the work is due to the problems of preserving the valuable of Tomsk historical and architectural heritage and this topic is poorly known . Wooden buildings in the classicism style were widely spread in the nineteenth century. They were classified as a residential development and were subjected to reconstruction and demolition in the Soviet period. Currently the wooden classical buildings are the most ancient and already quite rare and therefore it is necessary to conduct the research on its identification, study and systematization.
The novelty of the study is to conduct a comprehensive analysis and identify the typology of wooden buildings in the classicism style of Tomsk. In the course of the work the authors used the following methods: critical analysis of bibliographic sources, comparative architectural analysis and system-structural analysis of information, as well as creative synthesis in the formation of conclusions.
As a result of the conducted bibliographic and field studies the identified objects were divided into four main types according to their volume and spatial characteristics. It is established that the classic wooden building in Tomsk has great historical value. It is the material embodiment of constructive and technical knowledge, architectural and artistic traditions.
Models and prototypes of Voronezh construction of the first third of the 19th
Authors: Yenin A E , Guriev S N , Guriev G S 
Published: June 2021

Abstract
For the first time, the authors of the article publish the results of a comparative study of unique historical and architectural monuments of Voronezh built in the period of classicism, their compositional, decorative, and space-planning features, similarities and differences as compared to the architectural prototypes of Russian capitals, and their correspondence to the “model” projects of the late 18th and early 19th centuries. The results of the architectural-decorative, structural-compositional, morphological, and factor analysis, based on the most outstanding examples of Voronezh architecture of the first half of the 19th century, can enhance the understanding and deepen the scientific knowledge on the origins of the development of the classicist tradition in the provincial architecture of Voronezh. A correlation was found between Moscow buildings of the school of M. F. Kazakov and his contemporaries, as models and prototypes, and the classical architectural monuments of Voronezh. The prototypes of “model” projects designed by the architect V. P. Stasov, which completely correspond to the Voronezh buildings of the first half of the 19th century, were established. The determination of architectural analogues and models of classical Russian architecture, which have become the prototypes of provincial Voronezh architecture, based on the regulation and state control of the construction will significantly expand the attribution of historical and architectural monuments of classicism in Voronezh as an integral part of all-Russian architecture.
Matrix calculation of the period of non-rhythmic flow balanced at a slow rate
Authors: Zobkova N V , Timokhin D K 
Published: June 2021

Abstract
When designing the organization of construction by the flow method, the presence of unbalanced non-rhythmic flows is inevitable. The article deals with the issues of balancing non-rhythmic construction flows at a slow pace on the basis of a matrix algorithm for calculating the parameters of the construction flow. Methods of balancing construction flows are described. The matrix calculation of the parameters of the non-rhythmic flow balanced at a slow rate showed the properties of potential and paradoxical works. From the calculation results it is seen that increasing the rhythm accelerated processes on the allowed organizational downtime between jobs on the hook improves the quality of the construction of the flow, namely increasing the density ratio of the graph, reducing the total amount of organizational downtime, improve utilization of the scope of work. The total duration of the construction flow remains the same when using the properties of potential works and decreases when using paradoxical works.
Rational method for calculating statically indeterminate symmetric systems
Authors: Shagisultanova J N , Panfilov A V 
Published: June 2021

Abstract
Nowadays, the process of calculating structures is more and more entrusted to automatic calculation systems or artificial intelligence. This increases the accuracy and reliability of the calculations, but does not contribute to the understanding of the real work of the structures by the design engineer or architect. The main difficulty in carrying out such calculations is associated with the multifactorial nature of the solutions, and, as a rule, a significant number of unknowns and variables included in the calculation. The calculation is always carried out with the introduction of a certain degree of accuracy, which, in combination with a large number of variables, leads to the appearance of the effect of a cumulative decrease in the degree of reliability of the calculations carried out and the accumulation of statistical error. In turn, this can develop into a critical state. The technique presented in the article allows one to reduce the number of variables when solving problems of calculating statically indeterminate structures without changing the final result of the calculation.
Construction project management technology based on the theory of system stability
Authors: Tsopa N V , Malakhova V V , Fedorkina M S 
Published: June 2021

Abstract
Abstract The paper substantiates possibility and necessity of applying the system stability theory to the management of a construction project. Stability theories of automatic control systems are considered. Sustainability of construction projects is considered based on the sustainability theory of organizational systems. The indicators that characterize the degree of stability of the construction project are determined.
The main indicators of project sustainability are Net Present Income, project payback period, internal rate of return and project profitability. A mechanism for calculating these indicators before and after the application of the project management technology is presented. Approbation of the proposed project management technology based on sustainability indicators was carried out on the example of the construction of the “Villa Rose” cottage village. In the process of management, risks were identified at the stages of project implementation with the help of independent experts. The integral indicator of the project risk has been determined and the project risk management strategies have been selected.
Application of the Townsend-George wake theory to field measurements of wind turbine wakes
Authors: Neunaber Ingrid , Obligado Martin , Peinke Joachim , Aubrun Sandrine 
Published: June 2021

Abstract
As wind turbines are usually clustered in wind farms, knowledge of the evolution of the wind turbine wakes is important because downstream turbines will be exposed to them, causing higher loads and maintenance times. For that reason, wind turbine wakes have been studied intensively and different engineering wake models were derived. However, none of them is constructed from a few basic and robust assumptions, while such a formalism already exists for the axisymmetric turbulent wake. Therefore, we will apply these models to data obtained in a wind farm using a scanning LiDAR. The wakes of two wind turbines are analyzed in four different wind directions chosen so that their wakes will have different degrees of interaction. The axisymmetric wake models are found to perform better than the Jensen wake model, and the main source of improvement is shown to be the presence of a virtual origin. Indeed, a virtual origin is shown to also improve the Jensen wake model significantly. Overall, our results indicate that a view from classical axisymmetric wake theory can help to improve the understanding of the evolution of wind turbine wakes in the atmospheric boundary layer.
Evaluation of the Effects of Actuator Line Force Smearing on Wind Turbines Near-Wake Development
Authors: Cormier Marion , Weihing Pascal , Lutz Thorsten 
Published: June 2021

AbstractIn the present study, the effects of the actuator line force smearing on the predicted near-wake development of a model wind turbine are evaluated. To exclude the uncertainties related to the blade loads computation, the loads of a corresponding blade-resolving simulation are imposed. Three force projection functions are applied, which all radially scale with the local chord length: an isotropic Gauss force distribution, an anisotropic Gauss distribution with distinct projection widths in the chord and thickness directions, and a Gauss-Gumbel projection function which creates an airfoil-like force distribution in the chord direction. Comparisons with corresponding blade-resolving simulations and experimental results show a good agreement of the tip vortex core size, position and circulation. Comparison of the mid-wake instantaneous streamwise velocity with blade-resolving simulations shows a thinner vortex sheet and stronger effects of the trailed vortices in the actuator line simulation. Although the bound vortex shape scales with the projection function, no significant difference was observed in the resulting tip vortices and near-wake flow field between the three projection functions used. It is attributed to the similar projection width in the tip vortex region for all cases considered. With the chosen grid refinement in the tip vortex area and a smearing width that scales with the chord length, tip vortices that compare with high-resolution experiments and high-fidelity blade-resolving simulation could be generated with the actuator line approach.
Verification of induction zone models for wind farm annual energy production estimation
Authors: Forsting A Meyer , Rathmann OS , Laan MP van der , Troldborg N , Gribben B , Hawkes G , Branlard E 
Published: June 2021

Abstract
Fast engineering wake models are the backbone of wind farm annual energy production (AEP) estimators, whereas the addition of induction zone models in existing tools is a more recent response to rising concerns over wind farm blockage associated losses. Here, “blockage” describes the combined induction fields of all wind turbines inside a farm. Unlike the term might suggest, blockage not only reduces flow speeds, but also increases them; for instance along the outer edges of wind farms. Evaluating the overall impact on AEP of these gains and losses necessitates accurate wind farm induction models. Whilst engineering wake models are tuned to predict wind farm performance, existing induction zone models are all derived for accurately predicting the near field induction not the far field value—important for wind farm simulations. This paper presents the induction models implemented in the wind farm simulation tool PyWake, as well as results from novel analytical models and compares their far field predictions to RANS-AD simulations of different turbines. We demonstrate that when including blockage in AEP simulations, the downstream speed-ups need to be included to avoid an unrealistic bias toward AEP loss and that wake expansion significantly impacts induction at rated thrust levels.
Greenhouse gas emissions from food systems: building the evidence base
Authors: Tubiello Francesco N , Rosenzweig Cynthia , Conchedda Giulia , Karl Kevin , Gütschow Johannes , Xueyao Pan , Obli-Laryea Griffiths , Wanner Nathan , Qiu Sally Yue , Barros Julio De , Flammini Alessandro , Mencos-Contreras Erik , Souza Leonardo , Quadrelli Roberta , Heiðarsdóttir Hörn Halldórudóttir , Benoit Philippe , Hayek Matthew , Sandalow David 
Published: June 2021

Abstract
New estimates of greenhouse gas (GHG) emissions from the food system were developed at the country level, for the period 1990–2018, integrating data from crop and livestock production, on-farm energy use, land use and land use change, domestic food transport and food waste disposal. With these new country-level components in place, and by adding global and regional estimates of energy use in food supply chains, we estimate that total GHG emissions from the food system were about 16 CO2eq yr−1 in 2018, or one-third of the global anthropogenic total. Three quarters of these emissions, 13 Gt CO2eq yr−1, were generated either within the farm gate or in pre- and post-production activities, such as manufacturing, transport, processing, and waste disposal. The remainder was generated through land use change at the conversion boundaries of natural ecosystems to agricultural land. Results further indicate that pre- and post-production emissions were proportionally more important in developed than in developing countries, and that during 1990–2018, land use change emissions decreased while pre- and post-production emissions increased. We also report results on a per capita basis, showing world total food systems per capita emissions decreasing during 1990–2018 from 2.9 to 2.2 t CO2eq cap−1, with per capita emissions in developed countries about twice those in developing countries in 2018. Our findings also highlight that conventional IPCC categories, used by countries to report emissions in the National GHG inventory, systematically underestimate the contribution of the food system to total anthropogenic emissions. We provide a comparative mapping of food system categories and activities in order to better quantify food-related emissions in national reporting and identify mitigation opportunities across the entire food system.