Number Of Such Structures Research Articles

STUDY OF THE STRUCTURAL FEATURES OF STRING-CONCRETE SPAN STRUCTURES

Summary. The analysis of inspection results and experience in the operation of transport facilities show that bridges with string-concrete girders according to the standard designs VTP-16 and VTP-15 are in the worst condition. The wire prestressing reinforcement of these beams, which has a small diameter of 3 mm or 5 mm, loses its cross-section over time and breaks due to corrosion. This leads to the exhaustion of the residual service life of string-concrete girders on many bridges, which has caused several collapses in Ukraine in recent years. The structural features of string-concrete girders, including the use of small-diameter prestressed wire reinforcement, play a key role in their long-term operation and reliability. The number of such structures on Ukrainian roads of national importance reaches about 500 units, and their service life is more than 60 years. Lack of proper maintenance can lead to serious economic and safety problems. Analysing the technical condition of bridge span elements and identifying defects helps to improve traffic safety, extend the service life of bridges and reduce overall costs. Effective repair and strengthening of bridge structures ensure the normal functioning of the transport infrastructure, which is critical for the economic development and security of the country. This article investigates various aspects of the operation of bridges with string-concrete girders. The causes of defects are analysed and proposals are made to temporarily preserve the stability of structures prior to major repairs or reconstruction. The structural features of bridges with string-concrete girders reveal significant shortcomings that eventually lead to serious problems. Small-diameter wire prestressing reinforcement is prone to corrosion, which reduces its cross-section and leads to rupture. This, in turn, can lead to a complete collapse of the bridge span. Keywords: bridge, span structure, string-concrete, technical condition, defects, recommendations.

Cancers as structures corresponding to "infinite" ("immortal") fractals

It has been shown that the proliferation of cancer cells probably corresponds, as the cell proliferates, to “infinite” branching fractal (fractus – broken) structures. A cancer has an infinite number of such structures, compared to the finite number in blood vessels in a healthy body, but only until the macroorganism or the cancer itself dies. It can also be assumed that there is an “infinite fractality” of cancer cells in vitro because of the constant conditions of their culture and the absence of need for neoangiogenesis. Primary tumors and their metastases have a fractal outline (correlative CD) that is infinite, unpredictable, constantly growing, and non-stochastic, resulting from their development, progression, and “immortality”. Their fractality is non-linear, i.e. it speeds up, slows down, or may temporarily be stopped for many years. Determining the fractal size of a tumor can probably be used to assess the degree of its malignancy and thus improve therapy.

On the enumeration of plane bipolar posets and transversal structures

We show that plane bipolar posets (i.e., plane bipolar orientations with no transitive edge) and transversal structures can be set in correspondence to certain (weighted) models of quadrant walks, via suitable specializations of a bijection due to Kenyon, Miller, Sheffield and Wilson. We then derive exact and asymptotic counting results. In particular we prove (computationally and then bijectively) that the number of plane bipolar posets on n+2 vertices equals the number of plane permutations (i.e., avoiding the vincular pattern ▪ ) of size n. Regarding transversal structures, for each v≥0 we consider tn(v) the number of such structures with n+4 vertices and weight v per quadrangular inner face (the case v=0 corresponds to having only triangular inner faces). We obtain a recurrence to compute tn(v), and an asymptotic formula that for v=0 gives tn(0)∼c(27/2)nn−1−π/arccos(7/8) for some c>0, which also ensures that the associated generating function is not D-finite.

Ice structures assembled from cubic water clusters of D2d and S4 symmetry.

The study of self-assembly processes is of key importance for fundamental science and modern technologies. Cubic water clusters of D2d and S4 symmetry show great potential as building blocks for self-assembly. The objective of this paper is to construct possible ice structures formed by hydrogen bonding of these very stable water clusters. A number of such structures are herein presented, including quasi-2D and 3D ices as well as spatial layered and tubular ices. The energetics and structure of many configurations differing in the arrangement of hydrogen atoms in hydrogen bonds have been studied. It was established that the proton disorder of all such ices is of island type. The residual entropy of these ices is equal to ln(3)/4 in dimensionless form. For layered structures formed by the stacking of multiple bilayers, the determining role of the van der Waals interactions is shown. Note that, for all considered ices, the lowest-energy configurations are formed only by clusters of D2d symmetry.

Recovering building information model from 2D drawings for mechanical, electrical and plumbing systems of ageing buildings

Ageing buildings have become a significant concern for many cities, exacerbated by inadequate management and maintenance of Mechanical, Electrical, and Plumbing (MEP) systems. Building Information Modelling (BIM) enables efficient MEP Operation and Maintenance (O&M) through the digital representation of system information; however, many ageing buildings were constructed without BIM, and manual reconstruction is costly and inefficient due to the sheer number of such structures. Although some studies have proposed methods for automatically recovering BIM from 2D drawings, few are suitable for MEP systems due to the multiscale and irregular shapes of MEP components. To fill this gap, an automatic approach is proposed for recovering MEP model from 2D drawings with three modules: 1) semantic extraction by combining image cropping with Cascade Mask R-CNN to detect and segment multiscale, irregular MEP components; 2) geometric extraction by semantic-assisted image processing to extract contours and skeletons of irregular parts; and 3) Industry Foundation Class (IFC)-based BIM reconstruction via the open-source pythonOCC and IfcOpenShell. The performance was tested on two MEP systems with 335 and 282 multiscale and irregular elements, and the results show that the method recovered BIMs for the two MEP systems in 2.85 s and 0.79 s, with semantic extraction accuracy exceeding 0.9 and geometric error below 5%. This paper contributes to the existing body of knowledge by providing a semantic and geometric-based approach for recovering multiscale and irregular components from 2D drawings. Future studies could further improve the approach by integrating elevation drawings, reconstructing abstract symbols, and aligning text-geometry.

용암동굴 사례를 통한 제주특별자치도 도로 관리 조례 개선 연구

There are many lava caves on Jeju Island that were created by volcanic eruptions. Roads and residential facilities have been built above these lava caves, and the number of such structures is expected to increase with the development of Jeju Island. Various studies are being conducted to assess the safety of facilities, such as roads, built above lava caves, but currently there is no administrative system to support the safety management of the lava caves and their surrounding facilities. This study proposes revising and creating Jeju Island ordinances that are necessary for the safe construction and maintenance of major facilities on the island, where many lava caves are located. By revising the current ordinance on the preservation and management of natural caves and enacting an ordinance on the safety management of the upper ground of natural caves, it is expected that the possibility of ground subsidence in Jeju Island can be reduced.

Overview of Addressed Fiber Bragg Structures’ Development

An addressed fiber Bragg structure (AFBS) is a special type of fiber Bragg grating simultaneously performing the functions of a two-frequency radiation shaper and a sensitive element. An AFBS forms a two-frequency optical spectral response at its output, the difference frequency of which is invariant to measured physical fields and is referred to as the address frequency of the AFBS. Each of the AFBSs in the system has its own address frequency; therefore, a number of such structures can be interrogated simultaneously enabling the addressed multiplexing. In this article, we provide an overview of the theory and technology of AFBS, including the structures with three or more spectral components with various combinations of difference frequencies, both symmetrical and asymmetric. The subjects of interrogation of AFBSs, their fabrication and calibration are discussed as well. We also consider a wide range of applications in which AFBS can be used, covering such areas as oil and gas production, power engineering, transport, medicine, etc. In addition, the prospects for the further development of AFBS are proposed that mitigate the shortcomings of the current AFBSs’ state of the art and open up new possibilities of their application.

Blending as a Strategy to Attain Chiro-Optically Activity Polymers.

Two copolymers, one containing a chiral center and another without any asymmetric site are studied regarding their chiro-optical properties. The pure polymers do not show any signal of chiro-optical activity, only a smooth line is observed in the circular dichroism spectra, even for the chiral material. However, blends containing the achiral one as a major component show striking chiro-optical activity, originating by stable supramolecular structures whose size and shape remain unchanged, regardless of the blend composition. Only the number of such structures (composed by the chiral one), vary with blend composition. The results suggest that working with supramolecular morphology can be an important strategy to attain chiro-optical active polymers.

Digital Archiving of Historical Water Utilization Structures Using an Interdisciplinary Method

Human efforts to regulate watercourses and the use of water energy in their favour goes back into the past. Although historical water management and utilization structures are the proof of that, only a small number of such structures have been preserved. The article deals with the applied research of the use of modern geodetic laser scanning stations in combination with photogrammetric digital technologies for creating technical documentation and digital visualization of historical structures and national cultural monuments. Specifically, in this case, we will focus on the water utilization buildings – the water mill and water sawmill in the National Open-Air Museum, Rožnov pod Radhostěm, Czech Republic. Digital twins created using modern technologies may well serve not only for geo-tourism purposes but also as basis for potential future reconstruction or redevelopment projects. Keywords: 3D visualization; Digital photogrammetry; Digital twin; Industrial monuments; Laser scanning. DOI 10.35180/gse-2021-0046

Homology Modeling Using GPCRM Web Service.

Homology modeling methods are commonly used for quick and precise construction of a desired protein or its mutant using protein templates, which were determined by crystallography, cryo-EM, or NMR. Due to the increasing number of such structures, the obtained models are precise even in the case of small similarity between sequences of template and modeled proteins. The reason for that is a high evolutionary conservation in the structure regions responsible for keeping the function of proteins. This is also the case for G protein-coupled receptors (GPCRs), which constitute the largest family of membrane receptors with nearly 800 proteins. The GPCRM web service ( https://gpcrm.biomodellab.eu/ ) was set up for the nearly automatic generation of high-quality structures of modeled GPCRs. The three possible paths: "High similarity," "Quick path," and "Long path" allow the user to choose between a fast but less reliable path, up to more reliable but longer procedures. In the Advanced mode the service allows for user modifications including selection of template(s) and a manual adjustment of the sequence alignment.

Функціональне визначення громадської організації як соціального сервіс-провайдера

Здійснено обґрунтування нового виду інституції громадянського суспільства – громадської організації як соціального сервіс-провайдера. Запропоновано характеристику функціональних особливостей та принципові властивості, що актуалізують суспільно-корисні та сервісно-орієнтовані можливості оновленої організації. Уперше введено до наукового обігу принципові переваги залучення до публічної політики громадської організації як соціального сервіс-провайдера. Закцентовано увагу на синергетичному залученні до співпраці всіх суб’єктів публічно-управлінських відносин із прицілом на задоволення найпріоритетніших соціально-сервісних інтересів представників територіальних громад за допомогою застосування модерних управлінських і технологічних інновацій.

Training Neural Nets To Learn Reactive Potential Energy Surfaces Using Interactive Quantum Chemistry in Virtual Reality.

While the primary bottleneck to a number of computational workflows was not so long ago limited by processing power, the rise of machine learning technologies has resulted in an interesting paradigm shift, which places increasing value on issues related to data curation-that is, data size, quality, bias, format, and coverage. Increasingly, data-related issues are equally as important as the algorithmic methods used to process and learn from the data. Here we introduce an open-source graphics processing unit-accelerated neural network (NN) framework for learning reactive potential energy surfaces (PESs). To obtain training data for this NN framework, we investigate the use of real-time interactive ab initio molecular dynamics in virtual reality (iMD-VR) as a new data curation strategy that enables human users to rapidly sample geometries along reaction pathways. Focusing on hydrogen abstraction reactions of CN radical with isopentane, we compare the performance of NNs trained using iMD-VR data versus NNs trained using a more traditional method, namely, molecular dynamics (MD) constrained to sample a predefined grid of points along the hydrogen abstraction reaction coordinate. Both the NN trained using iMD-VR data and the NN trained using the constrained MD data reproduce important qualitative features of the reactive PESs, such as a low and early barrier to abstraction. Quantitative analysis shows that NN learning is sensitive to the data set used for training. Our results show that user-sampled structures obtained with the quantum chemical iMD-VR machinery enable excellent sampling in the vicinity of the minimum energy path (MEP). As a result, the NN trained on the iMD-VR data does very well predicting energies that are close to the MEP but less well predicting energies for "off-path" structures. The NN trained on the constrained MD data does better predicting high-energy off-path structures, given that it included a number of such structures in its training set.

Linear Structures of Correlation Function of Odd-Length Generalized Binary Barker Sequences

Spread-spectrum, wideband and pulse compression are well-known currently in use technologies for radar, telecommunication, navigation and other radio systems. The main theoretical problem concerning these technologies boils down to a synthesis and study of signals with certain correlation properties. A collection of mathematical models, which are generation rules for binary sequences, and related sequences with regular structures, which generalize structural features of known binary Barker sequences, were suggested and described in literature and may be taken as a kind of generalized binary Barker sequences. In contrast with known binary Barker sequences, which are known up to length N = 13 and widely used in radar and other radio systems and techniques, the generalized binary Barker sequences can be synthesized by means of deterministic generation rules for lengths N = 4 k –1, N = 4 k , N = 4 k +1, where k is a positive integer, and contain binary Barker sequences of lengths N = 3, 4, 5, 7, 11, 13 as a particular case. However, generally, the correlation function of generalized binary Barker sequence has a high value of sidelobes and therefore they cannot be used separately for high quality signal detection. Because of that, multiplicative complementary sets of generalized binary Barker sequences with a mutual sidelobe reduction are usable, similarly to Golay additive complementary sequences. It is shown that a structuring of the correlation function of odd-length generalized binary Barker sequences lies in the fact that the correlation function may be presented by some finite number of linear structures and singular ones, which are exceptional points of the correlation function. It has been determined that the number of such structures for any odd-length generalized binary Barker sequence does not exceed 7 pieces, of which no more than 3 pieces are linear structures, and no more than 4 pieces are exceptional points of the correlation function. On the basis of the structural analysis a complete system of analytical expressions, which based on above-mentioned linear and singular structures, for the correlation function of off-length generalized binary Barker sequence of any type and subtype is synthesized and presented. Examples of a structuring of the correlation function, which based on linear and singular structures, for odd-length generalized binary Barker sequences of different types and subtypes at k = 8 (lengths N = 31 and N = 33) are done. The theoretical significance of presented results lies in the obtaining of a new additional feature of “generalization” of generalized binary Barker sequences, namely, the structuring of their correlation functions based on linear structures. The obtained results make possible a description of signal components, which are based on odd-length generalized binary Barker sequences, after their matched filtering by means of linear constituents. Bibl. 10, Fig. 3, Tables 3.

Double-Sided Terahertz Imaging of Multilayered Glass Fiber-Reinforced Polymer

Polymer matrix composites (PMC) play important roles in modern industry. Increasing the number of such structures in aerospace, construction, and automotive applications enforces continuous monitoring of their condition. Nondestructive inspection of layered composite materials is much more complicated process than evaluation of homogenous, (mostly metallic) structures. Several nondestructive methods are utilized in this case (ultrasonics, shearography, tap testing, acoustic emission, digital radiography, infrared imaging) but none of them gives full description of evaluated structures. Thus, further development of NDT techniques should be studied. A pulsed terahertz method seems to be a good candidate for layered PMC inspection. It is based on picosecond electromagnetic pulses interacting with the evaluated structure. Differences of dielectric parameters enables detection of a particular layer in a layered material. In the case of multilayered structures, only layers close to surface can be detected. The response of deeper ones is averaged because of multiple reflections. In this paper a novel inspection procedure with a data processing algorithm is introduced. It is based on a double-sided measurement, acquired signal deconvolution, and data combining. In order to verify the application of the algorithm stress-subjected glass fiber-reinforced polymer (GFRP) was evaluated. The obtained results enabled detection and detailed analysis of delaminations introduced by stress treatment and proved the applicability of the proposed algorithm.

Crystal Structure of the Glycophorin A Transmembrane Dimer in Lipidic Cubic Phase.

The mechanisms of assembly and function for many important type I/II (single-pass) transmembrane (TM) receptors are proposed to involve the formation and/or alteration of specific interfaces among their membrane-embedded α-helical TM domains. The application of lipidic cubic phase (LCP) bilayer media for crystallization of single-α-helical TM complexes has the potential to provide valuable structural and mechanistic insights into many such systems. However, the fidelity of the interfaces observed in crowded crystalline arrays has been difficult to establish from the very limited number of such structures determined using X-ray diffraction data. Here we examine this issue using the glycophorin A (GpA) model system, whose homodimeric TM helix interface has been characterized by solution and solid-state NMR and biochemical techniques but never crystallographically. We report that a GpA-TM peptide readily crystallized in a monoolein cubic phase bilayer, yielding a dimeric α-helical structure that is in excellent agreement with previously reported NMR measurements made in several different types of host media. These results provide compelling support for the wider application of LCP techniques to enable X-ray crystallographic analysis of single-pass TM interactions.

TH‐EF‐BRB‐04: One‐Pixel Prototype of a Novel Polycrystalline CdTe‐Based Multilayer Detector for Radiation Therapy Imaging Applications

Purpose:Recent developments in polycrystalline CdTe‐based photovoltaics have resulted in a technology of inexpensive, large‐area structures possessing strong built‐in fields and superior radiation hardness. Stacking a large number of such structures (number of layers N>>1) into a detector with signal readout from individual layers produces a device with sufficient absorption under an MV beam, low signal spreading, no charge trapping, and low noise due to obviating the need for external biasing. We tested one‐pixel multilayer detector prototypes under a 6MV beam, compared their electrical parameters with those predicted by device modeling, and used the layer number‐signal data for verification of the energy spectrum unfolding algorithm.Methods:We modeled the energy deposition with depth of a CdTe‐based device under a 6MV beam with the Monte Carlo simulation package MCNP5. The results yielded charge carrier generation profiles in individual layers, which were then combined into structures of 10–12 layers. The profiles were used as input for modeling of current‐voltage (I‐V) characteristics with the device operation modeling software SCAPS‐1D. Modeling results were compared to measurements on several 1‐pixel multilayer structures under the 6MV beam of a Varian TrueBeam accelerator.Results:Measurements of I‐V characteristics for all layers of 1‐pixel multilayer structures established electrical parameters of best devices to be close to those modeled. A regularization algorithm for extracting the energy spectrum was successfully tested with these structures.Conclusion:The proposed multilayer structure adds a third dimension, depth‐signal reading, to the traditional 2‐D pixelation, allowing for the photon energy and source position to be obtained through signal processing. The latter processing relies on regularization approaches, similar to those developed for computed tomography, and thus have potential to significantly improve the quality of images under MV energy x‐ray sources of medical linear accelerators.This research is supported with NRC grant No. NRC‐HQ‐12‐G‐38‐0042

Counting Triangulations and Other Crossing-Free Structures via Onion Layers

Let $$P$$P be a set of $$n$$n points in the plane. A crossing-free structure on $$P$$P is a straight-edge plane graph with vertex set $$P$$P. Examples of crossing-free structures include triangulations and spanning cycles, also known as polygonalizations. In recent years, there has been a large amount of research trying to bound the number of such structures; in particular, bounding the number of (crossing-free) triangulations spanned by $$P$$P has received considerable attention. It is currently known that every set of $$n$$n points has at most O$$(30^{n})$$(30n) and at least $$\Omega (2.43^{n})$$Ω(2.43n) triangulations. However, much less is known about the algorithmic problem of counting crossing-free structures of a given set $$P$$P. In this paper, we develop a general technique for computing the number of crossing-free structures of an input set $$P$$P. We apply the technique to obtain algorithms for computing the number of triangulations, matchings, and spanning cycles of $$P$$P. The running time of our algorithms is upper-bounded by $$n^{\mathrm{O}(k)}$$nO(k), where $$k$$k is the number of onion layers of $$P$$P. In particular, for $$k = \hbox {O}(1)$$k=O(1) our algorithms run in polynomial time. Additionally, we show that our algorithm for counting triangulations in the worst case over all $$k$$k takes time O$$^{*}(3.1414^{n})$$?(3.1414n). [In the notations $$\Omega ^{*}(\cdot ), \hbox {O}^{*}(\cdot )$$Ω?(·),O?(·), and $$\Theta ^{*}(\cdot )$$??(·), we neglect polynomial terms and we just present the dominating exponential term.] Given that there are several well-studied configurations of points with at least $$\Omega (3.47^{n})$$Ω(3.47n) triangulations, and some even with $$\Omega (8.65^{n})$$Ω(8.65n) triangulations, our algorithm asymptotically outperforms any enumeration algorithm for such instances. We also show that our techniques are general enough to solve the Restricted-Triangulation-Counting-Problem, which we prove to be $$W[2]$$W[2]-hard in the parameter $$k$$k. This implies that in order to be fixed-parameter tractable, our general algorithm must rely on additional properties that are specific to the considered class of crossing-free structures.

Fractal Properties of the Solar Neighborhood Based on the Geneva-Copenhagen Survey

Abstract This study analyzes the fractal properties of the space distribution of stars in the solar neighborhood, based on the Geneva-Copenhagen Survey data. We demonstrate the existence of dynamically weakly coupled stochastic fractal structures in the circumsolar stellar medium. The number of such structures in the real stellar medium on 3 to 20 pc scales significantly exceeds the number of similar structures in the corresponding simulated random distributions. The total number of fractal structures depends on their characteristic size – the scale factor (Mf). We demonstrate that the structuredness of the stellar medium increases with the scale factor reaching its maximum around Mf ~ 18 pc and has a minimum around Mf ~ 5 pc. For Mf = 5 pc, the number of fractal structures in the survey is equal to 688, while for Mf = 18−20 pc the corresponding number exceeds 4000, which differs by more than three standard deviations from the mean fractal dimension D for random distributions. Practically, no structures are observed in random distributions in this domain of fractal dimensions. The proportion of fractal structures with [Fe/H]> 0 increases slowly with increasing scale factor and the number of such structures remains in the interval from 170 to 900. On the whole, the number of structures with [Fe/H]< 0 varies with scale factor in the same way as the total number of structures, and lies in the interval from 530 (Mf = 5 pc) to 3200 (Mf = 20 pc). Such significant differences between the fractal properties of the real stellar medium and its random simulations are due to peculiar “gravitational viscosity” of the gravitating medium. The results reported may play an important part in the study of structural properties and dynamic processes in the Galaxy and in the investigation of relaxation processes in particular.

D-101 CryoEM Studies of HIV-1 Envelope Glycoprotein

HIV-1 is an enveloped retrovirus that is the causative agent of AIDS. To date there is no effective vaccine that prevents acquisition of the virus, and therefore represents a significant burden on worldwide health. Structures of the HIV-1 envelope glycoprotein (Env) trimer in complex with neutralizing antibodies are a key component of ongoing rational vaccine design efforts aimed at creating stable immunogens that mimic Env. Thus, we have created a cryoEM pipeline to solve a number of such structures that are actively being used to design new immunogens for testing in animals. I will describe the types of information generated by cryoEM and the methods used to solve a diversity of structures that are representative of Env across multiple clades. By understanding the molecular determinants of trimer formation and quaternary epitope presentation across different Env sequences we can start to build a consensus for the creation of new and exciting immunogens.

LC3A‐Positive “Stone‐Like” Structures Predict an Adverse Prognosis of Gastric Cancer

Microtubule-associated protein light chain 3 (LC3A) is a reliable marker of autophagy that displays three distinct patterns of immunohistochemical staining in solid tumors: diffuse cytoplasmic staining, juxtanuclear staining, and staining of "stone-like" structures. These three patterns have a different prognostic significance in many solid tumors, but little is known about their influence in gastric cancer (GC). This study was a retrospective analysis of 188 GC patients from stages I to IV. The pattern of LC3A expression was examined in tumor and nontumor tissues by immunohistochemistry. Then, the association between the pattern of LC3A expression in GC and the prognosis was investigated by Kaplan-Meier analysis and the Cox proportional hazards model. Two distinct patterns of LC3A immunostaining (diffuse cytoplasmic expression and "stone-like" structures) were observed in GC tissues. LC3A-positive "stone-like" structures were found only in the tumors, and the number of such structures was correlated with both the tumor type and tumor stage. In addition, a high number of LC3A-positive "stone-like" structures was closely associated with an increased risk of recurrence after radical resection of stages I-III cancer (P < 0.001; HR = 0.205) and was associated with a lower overall survival rate for stage IV cancer (P < 0.001; HR = 0.364). Taken together, our data demonstrate that LC3A-positive "stone-like" structures can be used as an independent biomarker for an adverse prognosis of GC, suggesting that "stone-like" structures are correlated with the malignancy of this disease.