GLONASS precise orbit determination with identification of malfunctioning spacecraft

Due to the continued development of the GLONASS satellites, precise orbit determination (POD) still poses a series of challenges. This study examines the impact of introducing the analytical tube-wing model for GLONASS-M and the box-wing model for GLONASS-K in a series of hybrid POD strategies that consider both the analytical model and a series of empirical parameters. We assess the perturbing accelerations acting on GLONASS spacecraft based on the analytical model. All GLONASS satellites are equipped with laser retroreflectors for satellite laser ranging (SLR). We apply the SLR observations for the GLONASS POD in a series of GNSS + SLR combined solutions. The application of the box-wing model significantly improves GLONASS orbits, especially for GLONASS-K, reducing the STD of SLR residuals from 92.6 to 27.6 mm. Although the metadata for all GLONASS-M satellites reveal similar construction characteristics, we found differences in empirical accelerations and SLR offsets not only between GLONASS-M and GLONASS-M+ but also within the GLONASS-M+ series. Moreover, we identify satellites with inferior orbit solutions and check if we can improve them using the analytical model and SLR observations. For GLONASS-M SVN730, the STD of the SLR residuals for orbits determined using the empirical solution is 48.7 mm. The STD diminishes to 41.2 and 37.8 mm when introducing the tube-wing model and SLR observations, respectively. As a result, both the application of the SLR observations and the analytical model significantly improve the orbit solution as well as reduce systematic errors affecting orbits of GLONASS satellites.

Polygon-Based Hierarchical Planar Networks Based on Generalized Apollonian Construction

Experimentally observed complex networks are often scale-free, small-world and have an unexpectedly large number of small cycles. An Apollonian network is one notable example of a model network simultaneously having all three of these properties. This network is constructed by a deterministic procedure of consequentially splitting a triangle into smaller and smaller triangles. In this paper, a similar construction based on the consequential splitting of tetragons and other polygons with an even number of edges is presented. The suggested procedure is stochastic and results in the ensemble of planar scale-free graphs. In the limit of a large number of splittings, the degree distribution of the graph converges to a true power law with an exponent, which is smaller than three in the case of tetragons and larger than three for polygons with a larger number of edges. It is shown that it is possible to stochastically mix tetragon-based and hexagon-based constructions to obtain an ensemble of graphs with a tunable exponent of degree distribution. Other possible planar generalizations of the Apollonian procedure are also briefly discussed.

The comfort properties of hemp and flax blended denim fabrics with common industrial washing treatments

In this study, the moisture, thermal, and tactile comfort properties of flax and hemp blended denim fabrics treated with selected common industrial washing treatments were analyzed. Being used recently in denim fabric production, four different types of flax and hemp blended fabrics in different compositions and a reference cotton fabric were produced in similar construction and treated with rinse, stone, and bleach washes. The impact of fiber composition and the washing treatments on comfort properties was analyzed statistically. The findings revealed that the blended fabrics had better moisture comfort properties and thermal resistance than the cotton fabrics. Moreover, their tactile comfort properties were within acceptable limits. The washing treatments improved the comfort properties of all fabrics in a similar way.

The Equation of the Set of Natural Numbers Just to Sum

Systems of equations of the form X = Y + Z and X = C, in which the unknowns are sets of integers,”+” denotes pairwise sum of sets S + T = m + n m S, n T , and C is an ultimately periodic constant. When restricted to sets of natural numbers, such equations can be equally seen as language equations over a one-letter alphabet with concatenation and regular constants, and it is shown that such systems are computationally universal, in the sense that for every recursive set S N there exists a system with a unique solution containing T with S = n 16n + 13 T. For systems over sets of all integers, both positive and negative, there is a similar construction of a system with a unique solution S = {n|16n ∈ T} representing any hyper-arithmetical set S ⊆ N. Keywords: Language equations, Natural numbers, Equations of natural number.

On small black holes, KK monopoles and solitonic 5-branes

We review and extend results on higher-curvature corrections to different configurations describing a superposition of heterotic strings, KK monopoles, solitonic 5-branes and momentum waves. Depending on which sources are present, the low-energy fields describe a black hole, a soliton or a naked singularity. We show that this property is unaltered when perturbative higher-curvature corrections are included, provided the sources are fixed. On the other hand, this character may be changed by appropriate introduction (or removal) of sources regardless of the presence of curvature corrections, which constitutes a non-perturbative modification of the departing system. The general system of multicenter KK monopoles and their 5-brane charge induced by higher-curvature corrections is discussed in some detail, with special attention paid to the possibility of merging monopoles. Our results are particularly relevant for small black holes (Dabholkar-Harvey states, DH), which remain singular after quadratic curvature corrections are taken into account. When there are four non-compact dimensions, we notice the existence of a black hole with regular horizon whose entropy coincides with that of the DH states, but the charges and supersymmetry preserved by both configurations are different. A similar construction with five non-compact dimensions is possible, in this case with the same charges as DH, although it fails to reproduce the DH entropy and supersymmetry. No such configuration exists if d > 5, which we interpret as reflecting the necessity of having a 5-brane wrapping the compact space.

Substantiation of projected costs of investment and construction projects

Introduction. Investment value assessment, investment decision making, and successful implementation of investment and construction projects at all stages of their life cycles depend on high-quality feasibility studies focused on budget investments. The purpose of the work is to substantiate budget investments (calculation of the estimated (marginal) cost) by means of modeling and ensuring the compliance between the cost of similar types of work at other construction facilities and requested capacity values or types of work specified in design assignments or preliminary project documentation packages. Materials and methods. The co-authors analyzed the technical requirements and conditions affecting pre-project solutions (engineering studies), as well as the feasibility and expediency of the project implementation. The calculation of projected (marginal) project costs performed to substantiate budget investments in accordance with established administrative/territorial, organizational, technical and technological pre-design solutions and alternative engineering options, is implemented by means of modeling the costs to be incurred and assignments fulfilled at a similar construction facility. Results. Budget investments are substantiated by the analysis of the estimated (marginal) cost, performed on the basis of cost parameters and types of works performed at a similar construction facility and with regard for the features and requirements set in the design assignment and pre-project documentation. Conclusions. The significance of the research project consists in the practical application of the process of modeling the cost of similar construction facilities in the course of compiling a package of documents to substantiate the investments to be made, assess the investment value and make a contribution to investment decision making.

Effects of Earthquakes on Buildings in the Ibero-Maghrebian Region

The types of damage caused by earthquakes in buildings are closely related to the design and building techniques with which they have been built and the quality of the construction materials used. Most of countries with moderate to high seismic risk areas have implemented earthquake-resistant standards to prevent the collapse of buildings and minimize the severity of the damage. However, every new strong shake that occurs around the world reveals bad construction practices that could have been avoided, and the inadequacy or non-existence of earthquake-resistant standards aimed at reducing vulnerability to non-catastrophic levels. Based on the EMS-98 scale, in this chapter we will analyze three case studies of the Ibero-Maghrebian region that have been using similar construction patterns with similar catastrophic results for buildings despite the different dates in which they occurred and the different earthquake-resistant standards: SW Cape St. Vincent earthquake of February 28, 1969; Al Hoceima earthquake of February 24, 2004; and Lorca earthquake of May 11, 2011.

Pilgrimage as a Reproduction of Sacred Landscape in Finnish Karelia and the Russian Border Zone

This article examines how pilgrimages are constructed as a shared ritual of seeking sacred traces, thus creating and reproducing the sacred landscape. It studies an annual event with three connected Finnish Karelian Orthodox processions as a pilgrimage from an anthropological perspective. The event combines various motives, goals, and participants through a similar construction of the sacred landscape, with rituals of nding and creating the sacred in and for the landscape with personal experiences and stories of the imagined past. These processions, one of which crosses the border with modern Russia, attract participants motivated by both religious and heritage tourism. The article draws inspiration from Laura Stark’s notion of a ‘cult of traces’ and engages with pilgrimage studies and theories to offer an analysis of how various acts such as religious rituals, storytelling, and taking pictures are combined in the reproduction and reinvention of the imagined past and the creation of a marked meaningful present to construct and sustain a sacred landscape, thus forming a pilgrimage.

Non-Deterministic Semantics for Quantum States

In this work, we discuss the failure of the principle of truth functionality in the quantum formalism. By exploiting this failure, we import the formalism of N-matrix theory and non-deterministic semantics to the foundations of quantum mechanics. This is done by describing quantum states as particular valuations associated with infinite non-deterministic truth tables. This allows us to introduce a natural interpretation of quantum states in terms of a non-deterministic semantics. We also provide a similar construction for arbitrary probabilistic theories based in orthomodular lattices, allowing to study post-quantum models using logical techniques.