Towards dynamic property control of bridge spans

Regulation of the dynamic properties of bridge spans is a priority field of this research, which solves the problem of increasing the obsolescence and physical periods of bridge structures manifested both at the design stage of the load redistribution in the load bearing and during long-term operation.Over the past 40 years, technical bridge diagnostics has shown that the durability and safe long-term operation can be ensured by the improved calculations, operation and stress and strain control under the excess and over-calculated live loads.The aim of this work is to control the dynamic deformation and amplitude-frequency characteristics of bridge spans under harmonic random (non-stationary) oscillations of the span-vehicle system due to changes in the energy and stress state of the structure. The dynamic behavior of the span-vehicle system is based on the control for the amplitude-frequency characteristics of random oscillations by averaged values, the required spectral density being provided.The use of dynamic dampers for the system element control and the rigidity of junctions provide antiphase oscillations of the bridge span elements such as beams and decks, that leads to the unaccounted inertial forces.Another important element of the joint work imbalance of the bridge span elements during the dynamic load, are various defects, both in the deck design and load-bearing elements. It is assumed that the deck is a transfer layer (element) of vibrations induced by a vehicle in the beams. It is shown that the control for the dynamic properties is required in the case of a coincidence between the vehicle and beam stiffness and mass at the center of the system rigidity.The attention is paid to the conditions and dependencies between the dynamic load parameters and the stress-strain state of the bridge beams at the elastic and elastoplastic stages, with respect to the additional inertia of the system. This approach is the pilot in the Russian and foreign bridge construction in terms of experimental studies and testing of bridges for continuous random traffic.The dynamic testing of bridge spans for random traffic flow contributes to the creation of vibration diagnostic express laboratories necessary for the operation and maintenance of bridges.

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The aim of this article is to analyse the privatisation process in the Republic of Belarus. This analysis will help to answer two questions. Firstly, is Belarusian privatisation strategic in nature? Secondly, what theoretical framework explains Belarusian privatisation policy?Juxtaposing the process of transferring state property to the private sphere in Belarus with traditional theoretical frameworks explaining the causes and course of privatisation in the former Soviet bloc countries does not fully explain the actions of the Belarusian authorities. Privatisation transactions were not part of a broader plan to restructure the economy. They were carried out ad hoc, usually as a result of a combination of two factors – pressure from external actors and the need to raise budget funds.To explain the actions of President Alexander Lukashenko, it seems appropriate to use an approach derived from the concept of power-ownership developed by Russian researchers Yuri Latov and Rustem Nureev. This assumes the formation of property rights from above and directly links political power with property control. In this view, giving up control over property is tantamount to giving up political power.

Statistically Representative Metrology of Nanoparticles via Unsupervised Machine Learning of TEM Images

The morphology of nanoparticles governs their properties for a range of important applications. Thus, the ability to statistically correlate this key particle performance parameter is paramount in achieving accurate control of nanoparticle properties. Among several effective techniques for morphological characterization of nanoparticles, transmission electron microscopy (TEM) can provide a direct, accurate characterization of the details of nanoparticle structures and morphology at atomic resolution. However, manually analyzing a large number of TEM images is laborious. In this work, we demonstrate an efficient, robust and highly automated unsupervised machine learning method for the metrology of nanoparticle systems based on TEM images. Our method not only can achieve statistically significant analysis, but it is also robust against variable image quality, imaging modalities, and particle dispersions. The ability to efficiently gain statistically significant particle metrology is critical in advancing precise particle synthesis and accurate property control.

A System Identification and Implementation of a Soft Sensor for Freeform Bending

The primary goal of this study is the formulation of a soft sensor that predicts industrially relevant mechanical properties for freeform bending. This serves as the foundation of a closed-loop property control. It is hypothesized that by inline measurement of hardness, predictions regarding residual hoop stresses, local strength and strain level can be achieved. A novel hardness-based correlation scheme is introduced, which is implemented into an extended Kalman filter (EKF) and allows an inline prediction of local strength, residual hoop stresses and plasticity. Furthermore, the ultrasonic contact impedance (UCI) method is validated as a suitable inline measuring solution.

Constraints and limitations of concrete 3D printing in architecture

Purpose Additive manufacturing of concrete (AMoC) is an emerging technology for constructing buildings. However, due to the nature of the concrete property and constructing buildings in layers, constraints and limitations are encountered while applying AMoC in architecture. This paper aims to analyze the constraints and limitations that may be encountered while using AMoC in architecture. Design/methodology/approach A descriptive research approach is used to conduct this study. First, basic notions of AMoC are introduced. Then, challenges of AMoC, including hardware, material property, control and design, are addressed. Finally, strategies that may be used to overcome the challenges are discussed. Findings Factors influencing the success of AMoC include hardware, material, control methods, manufacturing process and design. Considering these issues in the early design phase is crucial to achieving a successful computer-aided design (CAD)/computer-aided manufacturing (CAM) integration to bring CAD and CAM benefits into the architecture industry. Originality/value In three-dimensional (3D) printing, objects are constructed layer by layer. Printing results are thus affected by the additive method (such as toolpath) and material properties (such as tensile strength and slump). Although previous studies attempt to improve AMoC, most of them focus on the manufacturing process. However, a successful application of AMoC in architecture needs to consider the possible constraints and limitations of concrete 3D printing. So far, research on the potential challenges of applying AMoC in architecture from a building lifecycle perspective is still limited. The study results of this study could be used to improve design and construction while applying AMoC in architecture.

Reservoir Characteristics and Main Controlling Factors of the Mesozoic Volcanic Rocks in the D Oilfield in Southern Gentle Slope Zone of the Laizhouwan Sag

The Mesozoic volcanic rocks are widely developed in the Bohai Bay basin. The D oilfield, located in the southeast of the Bohai Bay Basin, is a Cenozoic depression developed on the base of the Mesozoic. The types of the volcanic rocks are complex and the reservoir space is diverse. According to the characteristics of the volcanic reservoir, such as vertical multi-stage and strong heterogeneity, and based on the analysis of the volcanic core observation, thin section identification, logging data and seismic data, we analyzed the reservoir space type, physical property characteristics and reservoir physical property control factors of volcanic reservoir in the study area. The results show that the volcanic rocks in the study area are mainly volcanic breccia, andesite and tuff; the lithofacies types mainly include volcanic eruption facies, effusion facies and volcanic sedimentary facies, and the volcanic eruption facies is the most developed. Four types of volcanic reservoirs and 14 effective storage space types have been identified from the macroscopic and microscopic multi-scale, mainly intergranular pores, intergranular dissolution pores, intracrystalline pores, structural fractures and weathering dissolution fractures. Reservoir performance is mainly affected by lithology, lithofacies, tectonic activity and diagenesis. The primary pores in the upper part of exhalative and explosive facies are the most developed. Early cement filling is beneficial to the preservation of primary intergranular pore space and is an important prerequisite for the formation of secondary dissolution pores. Under the action of multi-stage tectonic movement and weathering leaching, the reservoir performance of volcanic rocks has been greatly improved, and the volcanic rocks with superimposed fractures and porosities are effective volcanic reservoirs.