Types Of Structural Elements Research Articles

GL-Net: Semantic segmentation for point clouds of shield tunnel via global feature learning and local feature discriminative aggregation

has gradually become the first choice of modern urban public transportation due to its advantages of safety and high-efficiency. Shield tunnel is an important type of subway tunnel, and its structural stability and safety play an important role in subway operation. The shield tunnels are prone to problems such as water leakage and tunnel collapse, which affect the safe operation of subways. Efficient monitoring methods are required to detect the status of subway tunnels. The data collection and accurate segmentation of key components of shield tunnels are the basis and key to the automatic monitoring of subway tunnels. This research presents a novel semantic segmentation method of three-dimensional (3-D) point clouds of typical structural elements (e.g., longitudinal joint, circumferential joints, bolt hole and grouting hole) in shield tunnel based on deep learning. In this method, we focus on how to make the network learn robust global features and complex local distribution patterns. Further, we propose a global and local feature encoding block (namely GL-block) to discriminatively aggregate local features while learning global representation. After multiple encodings by the GL-block, we design a global correlation modeling (GCM) module to establish a global awareness of each point. Finally, a weighted cross-entropy loss function is designed to solve the problem of unbalanced number of samples in each category of shield tunnel. In the experiments, we make a dataset of shield tunnel point clouds with a length of about 1,000 m collected by CNU-TS-1 (DU et al., 2018) mobile tunnel monitoring system, and use the dataset to train and test the segmentation ability of our method on the typical structural elements of shield tunnels. Experiments verify the effectiveness of our method by comparing with the other state-of-the-art 3-D point cloud semantic segmentation methods, and our method has an mIoU score of 73.02 %, which is at least 14.54 % higher than the other compared state-of-the-art networks. Also, we further verify the adaptability of our method to different tunnels and different laser scanning equipment, such as FARO, Leica and Z + F, and achieve very advanced performance.

Model of the Text of a Scientifc and Technical Article for Markup in the Corpus of Scientifc and Technical Texts

The paper proposes a model of the text of a scientifc and technical article for the automation of markup in the corpus of scientifc and technical texts. It is proved that when creating a corpus of scientifc and technical texts, it is necessary to take into account the structural features of texts of scientifc and technical articles. The necessity of adding structural markup to the corpus of scientifc and technical texts has been shown. It is noted that the texts of scientifc and technical articles have the same narration structure for all texts in this class, and also contain a limited set of structural elements. The features of compositional organization of the texts of scientifc and technical articles are analyzed. The approximate content of each of the elements of article structure is described. Compositional structure of the texts of scientifc and technical articles in Bekus-Naur notation is presented. A model of the text of a scientifc and technical article in the form of a graph, the vertices and edges of which are the full-fledged structural elements of a scientifc and technical article, is proposed. It is proved that the representation of a text of scientifc and technical article in the form of a graph makes it possible to determine the type of structural element and the degree of nesting in the process of computer analysis of the text by presenting the scientifc and technical article as a fnite set of its constituent parts. It is proved that the presence of structural markup in the corpus of scientifc and technical texts signifcantly expands its research potential and serves as the basis for the tasks of automatic processing of scientifc and technical texts.

LONGITUDINAL SHEAR TRANSFER IN COMPOSITE STEEL TRUSS AND CONCRETE (CSTC) BEAMS

AbstractThe Composite Steel Truss and Concrete (CSTC) beam represents an effective and structurally economical solution which can look back to a long tradition of successful use in Italy. This type of structural element consists of a truss made of structural steel which is partly or entirely encased in in‐situ cast concrete. The shear transfer mechanisms activated in these elements do not rely on dedicated shear connectors but on a mechanical interlocking between the truss and the surrounding concrete. In order to investigate the shear transfer mechanism and to support the development of appropriate design rules, 39 push‐out tests have been planned in accordance with EN 1994‐1‐1 B.2 testing procedure and they are presented in this work. Also, a finite element (FE) model was developed to study in detail the stress and strain field of the specimens. This paper will present the findings of the experimental campaign and numerical studies on the longitudinal shear transfer in CSTC beams.

ANÁLISE TEÓRICA PELO MÉTODO DA RESISTÊNCIA DIRETA DE SEÇÕES DUPLAS DE PERFIS DE AÇO FORMADOS A FRIO SOB COMPRESSÃO

The need for lighter, lower-cost construction has intensified, so the presence of cold-formed profiles has become common in civil construction, offering greater efficiency in the ability to withstand the current demands. The present article aimed at the theoretical study on the stability of double U and U lipped sections, composed of cold formed steel profiles, submitted to compression. Under the justification of analyzing the effectiveness of this type of structural element, with the help of the CUFSM Software that uses the Finite Strip Method, and verify the resistance by the Direct Strength Method (DSM). The objectives of this study were: to investigate the modeling in the CUFSM software for a double section with profiles connected to each other; and apply the DSM to the theoretical analysis of double sections with Brazilian commercial profiles. It was found that the variation in the number of connections influences the analysis and can reproduce the partial connection behavior. The application of folds proved to be efficient, with little influence on local instability and considerable influence on distortion instability. The DSM showed a loss of resistance for the models that presented a local failure mode, being, therefore, the most important factor regarding the resistance.

Algorithms for preliminary assessment of the technical condition of social buildings

The article presents a rational approach to a preliminary assessment of the technical condition of structural elements of social buildings. The authors use the example of kindergartens and schools in the city of Tyumen/ They take into account the date of construction, characteristics of structures and the possibility of choosing effective methods for carrying out repair work. The dependence of the detected damage on the type of structural elements and the building year was revealed. There is also given a rational sequence of actions for assessing the technical condition of building structures with recommendations for their elimination.

ГЕОДИНАМИКА И ИСТОРИЯ ФОРМИРОВАНИЯ ОКРАИННЫХ МОРЕЙ ЗАПАДНОЙ ЧАСТИ ТИХОГО ОКЕАНА КАК ВИХРЕВЫХ СТРУКТУР

In the tectonic structure of the Earth, formed by rotational processes, a stable regmatic network (tectonic framework) and structures of the central type (ring, vortex, etc.) are of the main importance. Lithosphere plates are global vortex systems arisen as a result of the tectonic flow of masses in the state of a viscous fluid. Eddy structures are tectonic complexes in which the results of vertical and horizontal tectonic movements combination are captured and can be recorded by direct geological observations. In the Western Pacific Ocean, it is noteworthy a series of structures in the form of a system of marginal seas representing the Western Pacific continent-ocean transition zone. The tectonic evolution of the West Pacific region is the formation of lithosphere eddies series in the continent-ocean junction zone. It is associated with the Earth mantle and upper shells (tectonospheres) energy interaction, due to the unstable regime of the planet’s rotational dynamics. Of particular interest are the global shear zones and eddies of the lithosphere formed as a result of horizontal and vertical tectonic movements combination. It is shown that: 1) all tectonic dislocations contain both horizontal and vertical components of the movement velocity, the former dominating in the structure formation of the region; 2) their interaction outcome is vortex and other nonlinear deformations of the lithosphere, which constitute the main type of structural elements of the region; 3) they are often accompanied by the tectonosphere magmatic activation in the form of convective movements and / or plumes “floating”; 4) the Western Pacific marginal-sea depressions are the funnels of convective cells, which formed lithosphere eddies under the conditions of a shift in the interacting lithosphere plates velocities.

Vertical Seismic Vibration of the Large-span Trussed Beam

Our country is located in a seismically active zone of the Earth. Accordingly, it is very important for us to consider the seismic load in the design of the building. The vertical component of the seismic acceleration of the base is often the cause of destruction of buildings during strong earthquakes. Consideration of the mentioned effect for certain types of structural elements of buildings is a standard requirement. Large-span steel truss belongs to these types of structures. The dynamic characteristics of the structure are the main parameters that form the seismic load. This paper considers a method for determining the dynamic characteristics of a large-span steel trussed beam, considering the influence of their bearing structures.

Three Novel Antisense Overlapping Genes in E. coli O157:H7 EDL933.

The abundance of long overlapping genes in prokaryotic genomes is likely to be significantly underestimated. To date, only a few examples of such genes are fully established. Using RNA sequencing and ribosome profiling, we found expression of novel overlapping open reading frames in Escherichia coli O157:H7 EDL933 (EHEC). Indeed, the overlapping candidate genes are equipped with typical structural elements required for transcription and translation, i.e., promoters, transcription start sites, as well as terminators, all of which were experimentally verified. Translationally arrested mutants, unable to produce the overlapping encoded protein, were found to have a growth disadvantage when grown competitively against the wild type. Thus, the phenotypes found imply biological functionality of the genes at the level of proteins produced. The addition of 3 more examples of prokaryotic overlapping genes to the currently limited, yet constantly growing pool of such genes emphasizes the underestimated coding capacity of bacterial genomes. IMPORTANCE The abundance of long overlapping genes in prokaryotic genomes is likely to be significantly underestimated, since such genes are not allowed in genome annotations. However, ribosome profiling catches mRNA in the moment of being template for protein production. Using this technique and subsequent experiments, we verified 3 novel overlapping genes encoded in antisense of known genes. This adds more examples of prokaryotic overlapping genes to the currently limited, yet constantly growing pool of such genes.

Geophysical evidence for a serpentine mud volcano in the relict slow-spreading center of the South China Sea

The seamounts formed in spreading centers are of basaltic with prominent gravity peaks and high density. But Longmen Seamount, 1.5 km high and ∼ 20 km wide, located in the relict slow-spreading center of the South China Sea, shows a weak gravity peak with a low-amplitude gravity variation (∼19 mGal). To reveal the geological origin of the unusual seamount, we conducted pre-stack depth-migrated image and 3D forward gravity modeling for Longmen Seamount based on the constraint from reflection and refraction seismic data. Our results show that bulk density and seismic velocity of Longmen Seamount is as low as ∼2.1 g/cm3, and 1.6–3.2 km/s, respectively, equivalent to that of poorly consolidated sediments. Furthermore, typical structural elements of the mud volcano system, such as a reflection blank zone, up-bent and downward bending reflections, are observed beneath LM Seamount. For the crust beneath LM Seamount is thin (1.6 km) and highly faulted revealed by numerous clear discontinuous reflections, it is easy for seawater to infiltrate through the thin crust and leads to a high degree of serpentinization of the upper mantle rocks. Combined with serpentine mud volcanoes featuring low bulk density and low seismic velocity, Longmen Seamount is most probably a serpentine mud volcano in a slow-spreading mid-ocean center. For the discovered serpentine mud volcanoes are all restricted to the convergent plate margins, this study will lead to a new understanding of the mechanism of serpentine mud volcanism.

Imaging Informatics Fellowship Curriculum: Building Consensus on the Most Critical Topics and the Future of the Informatics Fellowship.

The existing fellowship imaging informatics curriculum, established in 2004, has not undergone formal revision since its inception and inaccurately reflects present-day radiology infrastructure. It insufficiently equips trainees for today's informatics challenges as current practices require an understanding of advanced informatics processes and more complex system integration. We sought to address this issuebysurveying imaging informatics fellowship program directors across the country to determine the components and cutline for essential topics in a standardized imaging informatics curriculum, the consensus on essential versus supplementary knowledge, and the factors individual programs may use to determine if a newly developed topic is an essential topic. We further identified typical program structural elements and sought fellowship director consensus on offering official graduate trainee certification to imaging informatics fellows. Here, we aim to provide an imaging informatics fellowship director consensus on topics considered essential while still providing a framework for informatics fellowship programs to customize their individual curricula.

Free and forced vibration analysis of general multiple beam systems

As typical structural elements, multiple beam systems exist widely in many practical engineering applications. Existing research usually makes some simplifications in the systems and cannot analyze the actual structures very precisely. This paper focuses on studying both free and forced transverse vibrations of general multiple beam systems, which are a set of parallel Euler-Bernoulli beams joined by viscoelastic connections. In particular, the to-be-solved models are very generalized and it enables one to simultaneously consider (1) arbitrary number of beams, (2) any boundary conditions, (3) different beam lengths, (4) variable cross sections, (5) axial loads, and (6) various types of viscoelastic connections. Single uniform beams are introduced to modify the original governing equations to a set of inhomogeneous differential equations. Defining some mode-shape coefficients and state variables, a state-space approach is proposed to transfer these differential equations into a state-space equation. Natural frequencies and forced vibration responses are obtained through the state-space equation. With the obtained natural frequencies and a modal Rayleigh-Ritz method, the differential equations about mode shapes are transformed into several algebraic equations that are easily solved. The accuracy of the proposed methods is validated by numerical examples from previous literature and the finite element method. Finally, the requirements for the mode number in the developed methods are presented. This study is of great significance in analyzing and designing multiple beam systems in engineering practices.

Aesthetic aspect of architectural space development for creative activity of children in a modern school

Purpose: The aim of this work is to determine the architectural space components for the creative activity of children in a modern school. Design/methodology: The description of modern design and construction of school buildings in Russia and abroad; identification of factors influencing the formation of the aesthetic aspect of the architectural space of a modern school; theoretical modeling of typological layout of individual structural elements of the architectural space for creative activities in a modern school; analysis of the functional zoning and compositional parameters of the architectural space to identify the architectural space qualitative parameters disclosing the creative potential of students. Research findings: Identification of the main algorithms of the architectural space design for the creative activity of students in a school with a specific atmosphere that has a beneficial effect on the perception of new knowledge and disclosure of the creative potential of students. Practical implications: The obtained results and proposed recommendations can be used in green architecture and development of regulatory documents on the school building design; the program preparation in project activities; in studying the individual structural components of the architectural environment within the artistic and aesthetic aspect. Originality/value: Architectural means determine the formation of the aesthetically oriented architectural environment for creative activities in modern schools and identify the qualitative parameters of the given space. The architectural environment of the creative activity represents a new type of individual structural elements of a modern school building focused on a disclosure and growth of creative potential of students with optimum opportunities.

Studying the web notch shape effect on shear load: Numerical analysis for steel beams

The connections made for steel beams are used quite often, in which a part of the beam cross-section needs to be cut at the connection joint. There are many shapes in which the location of the cutting part of the web is formed, but this is done in a manner where previous studies or calculations have not been made and may cause an adverse effect on the section's resistance to stresses. For this reason, a finite element (FE) analysis was conducted on 34 models in this research, among which many variables and notched shapes were selected that could be implemented in the web cutting process. Some specimens were first compared that were used for studying in the experiments of the previous research. Great agreement and high accuracy were obtained in the use of FE numerical analysis in the modeling of this type of steel structural elements. The maximum load capacity, the distribution of normal stresses as well as the shear stresses at the notched zone were measured. From the study of the different variables, it was observed that the use of a quarter-circle notch was the best shape for locating the beam web cutting, as the increase of the load ratio reached 1.14 when compared to the right angle. The use of a half-circle notch, either from one or both sides of the beam web, negatively affects the web's resistance to stress. A quarter-circle notched from both sides must also be used to increase the load capacity if the flange is cut from both sides.

Optimalni projekt drvenih konstrukcija izloženih djelovanju požara uporabom metaheurističkog algoritma

One of the major tasks of structural engineers is to reduce the building cost. Thus, an effective optimization of structural elements is gaining in importance every day. The teaching-learning-based optimization (TLBO), which is one of metaheuristic algorithms, for an optimum design and analysis of timber structures under fire in accordance with EN 1995 1-2 (Eurocode 5: Design of Timber structures - Part 1- 2 General structural fire design), is proposed in this study. The objective function in this algorithm is the building cost of timber structures under fire, considering premature collapse of the structure and limitation of fire spread. A structure made of wood is investigated under different times of fire exposure in order to determine the cross-section and wood type of structural elements. In conclusion, the cross section and strength of structural elements made of wood can be effectively and rapidly optimized with TLBO according to EN 1995 1-2.

A New Methodology for Bridge Inspections in Linear Infrastructures from Optical Images and HD Videos Obtained by UAV

Many bridges and other structures worldwide present a lack of maintenance or a need for rehabilitation. The first step in the rehabilitation process is to perform a bridge inspection to know the bridge′s current state. Routine bridge inspections are usually based only on visual recognition. In this paper, a methodology for bridge inspections in communication routes using images acquired by unmanned aerial vehicle (UAV) flights is proposed. This provides access to the upper parts of the structure safely and without traffic disruptions. Then, a standardized and systematized novel image acquisition protocol is applied for data acquisition. Afterwards, the images are studied by civil engineers for damage identification and description. Then, specific structural inspection forms are completed using the acquired information. Recommendations about the need of new and more detailed inspections should be included at this stage when needed. The suggested methodology was tested on two railway bridges in France. Image acquisition of these structures was performed using an UAV for its ability to provide an expert assessment of the damage level. The main advantage of this method is that it makes it possible to safely accurately identify diverse damages in structures without the need for a specialised engineer to go to the site. Moreover, the videos can be watched by as many engineers as needed with no personal movement. The main objective of this work is to describe the systematized methodology for the development of bridge inspection tasks using a UAV system. According to this proposal, the in situ inspection by a specialised engineer is replaced by images and videos obtained from an UAV flight by a trained flight operator. To this aim, a systematized image/videos acquisition method is defined for the study of the morphology and typology of the structural elements of the inspected bridges. Additionally, specific inspection forms are proposed for every type of structural element. The recorded information will allow structural engineers to perform a postanalysis of the damage affecting the bridges and to evaluate the subsequent recommendations.

Utjecaji i dinamičko ponašanje interakcije tla i okvirne konstrukcije

The effect and behaviour of soil - framed-structure interaction (SSI) under dynamic load conditions are presented in the paper. All civil engineering structures involve various types of structural elements that are in direct contact with soil. Hence, a new thin-layer interface element, based on the concept of the finite element method, is formulated. The formulation is elaborated using a combination of degrees of freedom of the top and bottom sides of the interface elements. The compatibility conditions of displacements between beam elements and quadrilateral soil elements are applied. Thus, a numerical program integrating the thin-layer interface element is developed for this purpose. The obtained results show that interaction between the soil and a framed structure has a considerable influence on the structural dynamic response of system components. Additionally, a parametric study has been elaborated to quantify the significance of interface behaviour on the soil and on the framed structure under dynamic load.

Calmodulin interactions within the N2A region of titin

One of the most interesting elastic proteins is the muscle protein titin, which exists in the sarcomere of the muscle and plays a critical role in maintaining myofibril integrity and in passive force. Within titin, there are several types of structural elements that work synergistically to produce the various functions of the protein. Our lab has recently been focused on the N2A region, which is located in the center of the I-band region of titin. Structurally, the N2A region is comprised of four immunoglobulin domains and a unique region that consists of 117 amino acids in both ordered and disordered regions.

ALGORITHMS FOR PRELIMINARY EVALUATIONOF THE TECHNICAL STATE OF SOCIAL BUILDINGS

The article presents an algorithm for the preliminary evaluation of the technical condition of structural elements of social buildings (on the example of kindergartens and schools in Tyumen), taking into account the date of construction, the characteristics of structures and the possibility of choosing the effective methods of repair. The correlation between the detected damages and the type of structural elements as well as the year of building construction was revealed. A rational sequence of actions to evaluate the technical state of the structures of buildings with recommendations for their elimination has been proposed.

In Ukrainian

In this paper, the nature of the chemical activity of pyrolyzed nanostructured carbon materials (PNCM), in particular active carbon (AC), in reactions of electron transfer considered from a single position, reflecting the priority role of paramagnetic centers and edge defunctionaled carbon atoms of carbon microcristallites (CMC) due to pyrolysis of precursors. Clusters in the form of polycyclic aromatic hydrocarbons with open (OES) and closed (CES) electronic shells containing terminal hydrogen atoms (or their vacancies) and different terminal functional groups depending on specific model reactions of radical recombination, combination, replacement and elimination were used to model of nanographenes (NG) and CM. Quantum-chemical calculations of molecular models of NG and CMC and heat effects of model reactions were performed in frames of the density functional theory (DFT) using extended valence-splitted basis 6-31G(d) with full geometry optimization of concrete molecules, ions, radicals and NG models. The energies of boundary orbitals were calculated by means of the restricted Hartry-Fock method for objects with closed (RHF) and open (ROHF) electronic shells. The total energies of small negative ions (HOO-, HO-) and anion-radical О2•‾) were given as the sum of calculated total energies of these compounds and their experimental electron affinities. The estimation of probability of considered chemical transformations was carried out on the base on the well-known Bell-Evans-Polyani principle about the inverse correlation of the thermal effects of reactions and its activation energies. It is shown that the energy gap ΔЕ (energy difference of boundary orbitals levels) in simulated nanographens should depend on a number of factors: the periphery structure of models, its size and shape, the number and nature of various structural defects, electronic states of NG. When considering possible chemical transformations on the AC surface, rectangular models of NG were used, for which the simple classification by type and number of edge structural elements of the carbon lattice was proposed. Quantum chemical calculations of molecular models of NG and CNC and the energy of model reactions in frames of DTF showed that the chemisorption of free radicals (3O2 and N•O), as recombination at free radical centers (FRC), should occur with significant heat effects. Such calculations give reason to believe that FRC play an important role in formation of the functional cover on the periphery of NG in CMC of studied materials. On the base of of cluster models of active carbon with OES new ideas about possible reactions mechanisms of radical-anion О2•‾ formation and decomposition of hydrogen peroxide on the surface of active carbon are offered. Explanation of increased activity of AC reduced by hydrogen in H2O2 decomposition is given. It is shown that these PNCM models, as first of all AC, allow to adequately describe their semiconductor nature and acid-base properties of such materials.

On the Effectiveness of Vibration-Based Monitoring for Integrity Management of Prestressed Structures

In this paper, the effectiveness of vibration-based tests for the detection of damages for prestressed concrete beams is investigated. Despite large research efforts, discrepant and sometimes contradicting conclusions have been drawn regarding the efficacy and reliability of vibration-based monitoring for prestressed structures. Herein, a contribution to this discussion is provided by tackling the problem from a different perspective. Specifically, the question that this paper intends to answer is: “Do vibration-based tests support decision-makers in integrity management operations for prestressed elements?” The discussion is carried out by comparing the performance of prestressed and ordinary reinforced concrete beams with similar capacities. Both analytical and numerical case studies are considered. Results show that, for prestressed beams, in contrast to reinforced concrete beams, modal parameters can provide information regarding damage only when the structure is close to its ultimate conditions. This makes this information hardly useful for integrity management purposes and the effectiveness of vibration-based tests questionable for this type of structural element.