Dynamic Diagrams Research Articles

Gelation and Re-entrance in Mixtures of Soft Colloids and Linear Polymers of Equal Size.

Liquid mixtures composed of colloidal particles and much smaller non-adsorbing linear homopolymers can undergo a gelation transition due to polymer-mediated depletion forces. We now show that the addition of linear polymers to suspensions of soft colloids having the same hydrodynamic size yields a liquid-to-gel-to-re-entrant liquid transition. In particular, the dynamic state diagram of 1,4-polybutadiene star-linear polymer mixtures was determined with the help of linear viscoelastic and small-angle X-ray scattering experiments. While keeping the star polymers below their nominal overlap concentration, a gel was formed upon increasing the linear polymer content. Further addition of linear chains yielded a re-entrant liquid. This unexpected behavior was rationalized by the interplay of three possible phenomena: (i) depletion interactions, driven by the size disparity between the stars and the polymer length scale which is the mesh size of its entanglement network; (ii) colloidal deswelling due to the increased osmotic pressure exerted onto the stars; and (iii) a concomitant progressive suppression of the depletion efficiency on increasing the polymer concentration due to reduced mesh size, hence a smaller range of attraction. Our results unveil an exciting new way to tailor the flow of soft colloids and highlight a largely unexplored path to engineer soft colloidal mixtures.

Dynamics of a vibratory screening conveyor equipped with a controllable centrifugal exciter

Vibratory screening, sieving, and conveying processes are widely used in various industries. Among a great variety of vibration exciters, the unbalanced rotors are the most reliable, simple, and widespread ones. Due to the changeable operating conditions of vibratory equipment, in some cases, there occurs a necessity to control the disturbance (excitation) parameters of the corresponding drives. The primary purpose of this study is to substantiate the design parameters and analyze the dynamic characteristics of the vibratory screening conveyor based on the single-mass oscillatory system, and equipped with the controllable centrifugal exciter. The research methodology consists of several basic stages: developing the conveyor’s dynamic diagram and deducing the differential equations of the system’s motion; designing the machine’s 3D-model and defining its main geometrical and inertial parameters; numerical modeling of the system’s oscillations in the Mathematica software; simulating the conveyor’s operation in the SolidWorks software. The research results present the time dependencies of the conveyor’s working member kinematic parameters at different eccentricities of the unbalanced mass. The main scientific novelty of this research is substantiating the idea and possibilities of implementing the enhanced controllable centrifugal exciter for changing the disturbance (excitation) conditions of the vibratory screening and conveying machines. The proposed ideas and obtained results can be used by researchers and designers of similar equipment while developing control systems for regulating its operational efficiency (performance) in accordance with the changeable loading conditions or technological requirements.

Dynamics of a wheeled robot driven by an unbalanced rotor and equipped with the overrunning clutches

Vibration-driven locomotion principles are currently of significant interest among designers and researchers dealing with mobile robotics. Among a great variety of robots chasses, the wheeled ones are the most commonly used. The major purpose of this study consists in defining the dynamic characteristics of the wheeled vibration-driven robot equipped with the centrifugal (inertial) vibration exciter (unbalanced rotor) and overrunning clutches ensuring the robot’s wheels rotation in one direction. The research methodology is divided into three basic stages: developing the robot’s dynamic diagram and deriving the motion equations followed by numerical modeling in the Mathematica software; designing the 3D-model and simulating the robot motion in the SolidWorks software; creating the experimental prototype and conducting the full-scale tests. The obtained results show the time dependencies of the robot’s body acceleration, speed, and displacement at certain operational conditions. The main scientific novelty of the paper resides in substantiating the relationships between the robot’s design parameters and its dynamic characteristics under different operational conditions. The performed investigations can be useful for researchers and designers dealing with vibration-driven robots, capsule-type locomotion systems, pipelines inspecting vehicles, etc.

Development of a simulator for hydraulic power plant personnel

As annals show, the first hydroelectric power plants were built in Russia in 1802 – 1806. During the Soviet period of energy development, emphasis was placed on the special role of the country’s unified national economic electrification plan — GOELRO, which was approved on December 22, 1920. The chapter of the plan dedicated to hydropower was entitled "Electrification and water energy". In today’s Russia about 1/3 of power is produced at hydroelectric power plants. Accordingly, there arise issues of advanced training of personnel of hydroelectric power plants, which can be provided by the introduction of simulators for targeted training of personnel to work, both in normal modes and in pre-emergency and emergency situations, as close as possible to real ones. Unfortunately, the developers of simulators in the Russian energy sector have so far focused on creating simulators for thermal power plants, leaving hydroelectric power plants neglected. It can therefore be assumed that this article, which examines a simulator with dynamic computer mimic diagrams of hydraulic units and electrical circuits of one of the Russian hydroelectric power plants, will arouse some interest among readers of the journal and potential customers. The article describes a prototype facility, the composition of the simulator, which includes a model of the facility and operating modes, a model of the control system, a model of the protection system, a model of locks, a model of emergency and warning alarms, describes in detail the training and methodological support of the simulator complex, including models of training scenarios, an input model, a monitoring program, protocols and instructions. The hydroelectric power plant simulator presented in the article is versatile and can be applied both as a means of training and examination of operational personnel, and as a means for conducting professional skills competitions.

An Algorithm for Dynamic Identification of Low-Voltage Topology

The topology identification of the station area includes two types of household-transformation relationship and branch relationship identification. In this paper, the station area identification signal is sent in phases through the intelligent distribution transformer terminal deployed in the station area, and the branch identification slave installed in each branch line and the terminal identification slave installed in the meter box receive this identification signal to realize the household-transformation relationship and phase identification in the station area. At the same time, the terminal identification slave sends a branch current identification signal, and the branch station identification slave receives the branch identification signal so that the branch relationship can be recognized correctly. Through the identification of household-transformation relationships, phase sequence identification, and branch relationship identification, the correct dynamic topology diagram of the station area can be established.

Study on hybrid fibre reinforced UHPC beams under single and repeated lateral impact loading

This paper investigates the dynamic response of hybrid fibre reinforced ultra-high performance concrete (UHPC) beams against single and repeated low-velocity impact loads. A brief description of the drop weight impact tests on the UHPC beams was presented first followed by the development of the material and structural model in finite element analysis. A plasticity-based concrete material model with validated compressive and tensile strength surface and damage algorithm was adopted for hybrid fibre reinforced UHPC material. Based on the test results, the bond-slip behaviour between steel rebar and UHPC matrix was developed in an empirical form and incorporated in the model. Compared to the model with the bond-slip definition, the model with perfect bonding was found to underestimate the maximum mid-span deflection, which highlighted the necessity of considering the bond-slip behaviour in dynamic analysis where large deflection occurs. The repeated impact tests were performed numerically, and the results were validated with experimental data. A parametric study was then performed to investigate the effect of key parameters, including different impact energy and the same impact energy but different impact numbers. The results indicated when the total energy increased, the repeated impact loads became more hazardous than the single impact load. With the validated model, the dynamic shear force and bending moment distribution diagrams were compared to study the failure mechanism in single and repeated impact loads.

RESEARCH TO PROPOSE THE MAXIMUM LONGITUDINAL GRADE FOR MILITARY ROADS

In order to serve coaching and combat readiness in the new situations, in recent years, our Army has been invested and equipped with many innovative and modern weapons and armaments. Many types of them are placed on military vehicles which have peculiar sizes, loads and dynamic characteristics. Therefore, military ways whould have been designed separate geometric elements, especially in the difficult conditions: craggy terrain conditions, or on military routes that are quickly built without pavement. In this article, the authors studied the theoretical basis and applied it to build dynamic factor diagrams of some special military vehicles by analytically method as a basis of offering the maximum longitudinal grade for specific military roads of the Vietnam People’s Army.

3D-QSAR Studies, Molecular Docking, Molecular Dynamic Simulation, and ADMET Proprieties of Novel Pteridinone Derivatives as PLK1 Inhibitors for the Treatment of Prostate Cancer.

Overexpression of polo-like kinase 1 (PLK1) has been found in many different types of cancers. With its essential role in cell proliferation, PLK1 has been determined to be a broad-spectrum anti-cancer target. In this study, 3D-QSAR, molecular docking, and molecular dynamics (MD) simulations were applied on a series of novel pteridinone derivatives as PLK1 inhibitors to discover anti-cancer drug candidates. In this work, three models-CoMFA (Q² = 0.67, R² = 0.992), CoMSIA/SHE (Q² = 0.69, R² = 0.974), and CoMSIA/SEAH (Q² = 0.66, R² = 0.975)-of pteridinone derivatives were established. The three models that were established gave Rpred2 = 0.683, Rpred 2= 0.758, and Rpred 2= 0.767, respectively. Thus, the predictive abilities of the three proposed models were successfully evaluated. The relations between the different champs and activities were well-demonstrated by the contour chart of the CoMFA and CoMSIA/SEAH models. The results of molecular docking indicated that residues R136, R57, Y133, L69, L82, and Y139 were the active sites of the PLK1 protein (PDB code: 2RKU), in which the more active ligands can inhibit the enzyme of PLK1. The results of the molecular dynamic MD simulation diagram were obtained to reinforce the previous molecular docking results, which showed that both inhibitors remained stable in the active sites of the PLK1 protein (PDB code: 2RKU) for 50 ns. Finally, a check of the ADME-Tox properties of the two most active molecules showed that molecular N° 28 could represent a good drug candidate for the therapy of prostate cancer diseases.

DIDGITAL ІНСТРУМЕНТАРІЙ СУЧАСНИХ МАРКЕТИНГОВИХ ДОСЛІДЖЕНЬ

The article considers the main aspects that determine the need for new methods and tools for researching world markets. Volume and variety of data. Consumers and companies generate large amounts of data through the Internet, social networks, e-commerce and other sources. Researchers have to work with this large amount of data and study various aspects of the market. Due to global trade and the internationalization of business, markets are becoming more connected and complex. Researchers should take into account the influence of international factors and relationships on market dynamics. Changes in consumer preferences and approaches to purchases require constant analysis and adaptation of marketing strategies. The use of advanced technologies, such as artificial intelligence, machine learning, big data analysis, etc., allows for more accurate and faster analytical operations. Traditional research methods may not be a sufficient answer to the complex questions of modern markets. Researchers must be ready to implement new techniques and tools. Growing competitive pressure requires more accurate and operational analysis of markets to ensure competitiveness. It is suggested to make the first steps of marketing research using modern digital technologies on the example of the foreign trade market of Ukraine. For high-quality visualization of a large amount of information during marketing research, it is suggested to use dynamic diagrams, in particular, when analyzing the commodity structure of Ukraine's foreign trade. It is noted that the methodology of marketing research is a system of methods and approaches aimed at studying the market and collecting the necessary information for making informed decisions in the field of marketing. The main principles of this methodology include: data relevance, project specificity, combination of methods, hypothesis testing, field and office research, feedback. The use of dynamic diagrams allows: dividing a large amount of data into smaller groups and using colors for their visualization; choosing the right type of graphics; providing the ability to filter and interact with data.

Experimental and numerical study on the impact resistance of ultra-high performance concrete strengthened RC beams

To enhance the impact resistance of built reinforced concrete (RC) members, the effectiveness of using ultra-high performance concrete (UHPC) for strengthening RC structures was investigated in this study. The mechanical properties of UHPC were evaluated by the uniaxial compression, tension and flexural bending tests. Drop weights with hemispherical and wedge-shaped indenter were adopted to impact the beam specimens with and without UHPC strengthening. A total of six beams, including three control RC beams and three UHPC jacketed RC (RC-UHPC) beams, were tested. The beams were prestressed in the axial direction with a 200 kN force. The test results revealed that the UHPC jackets improved the structural impact resistance. With an impact mass of 411 kg and an impact velocity of 4.95 m/s, the maximum and residual deflection of the RC-UHPC specimen decreased by 15.3 % and 21.1 % as compared to the RC control specimen, and the failure mode shifted from diagonal shear failure to flexural failure. To further investigate the dynamic responses of the beams, a detailed finite element model was established and validated with the test results in terms of the impact force, structural deflection and damage profile. The dynamic shear force and bending moment distribution diagrams were numerically derived to examine the failure mechanism of the test specimens. Finally, a parametric study was conducted to evaluate the effect of different impact locations and UHPC jacket length on the impact resistance of strengthened RC beams.

Construction of maps for dynamic modes and bifurcation diagrams in nonlinear dynamics using the Maple computer mathematics software package

The paper considers algorithms for constructing maps of dynamic regimes and bifurcation diagrams in nonlinear dynamics using the example of some oscillatory systems and discrete mappings. The work is educational and methodical and can be used in the educational process when studying the disciplines “Nonlinear dynamics” and “Theory of oscillatory systems”.

A numerical study of the droplet impact dynamics on a two-dimensional random rough surface

Considerable efforts had been devoted to investigating numerically the droplet impact dynamics on a superhydrophobic surface, whereas most of these numerical simulations were restricted to the two-dimensional (2D) axisymmetric coordinate system with the one-dimensional (1D) substrate surface. In this work, a three-dimensional (3D) computational fluid dynamics (CFD) model, which intergrew a 2D random rough surface, was proposed to investigate the droplet impact dynamics, and the multi-phase flow issue was solved by the Navier–Stokes equations. It is remarkable that the 3D CFD model revealed several significant dynamic details that were not easily captured in a 2D axisymmetric coordinate system or practical experiments. For instance, the 3D CFD model provided a unique perspective to understand the varying dynamic behaviors of impinged droplet in terms of the velocity streamline and dynamic viscosity analyses. Herein, the dynamic viscosity diagram revealed that the sprawl droplet on the 2D random rough surface was classified as the Cassie state, while as the Wenzel state for the smooth surface, which also explained the better bouncing behaviors of the droplet from the random rough surface. Accordingly, we suggested a visual way to evaluate the solid–liquid contact area surrounded by the triple-phase contact line. The effects of finger protrusion and central cavity growth from the sprawl droplet on the vortex generation were further analyzed on the ground of the velocity amplitude distribution and streamline data. The present work can provide early guidance to inquire into the impact dynamics of droplets on the random rough surface.

Impact of the ship hull geometry on sinkage

This paper aims to analyse how hull geometry affects the ships sinkage. A 12 ship database is used to study hull forms effect on sinkage both experimentally and numerically, which sinkage towing test results – collected from previous experimental campaigns – were compared towards the ships form coefficients. The negative effect caused by a draft increase was studied and the bow shapes effect was analysed in detail with the experimental results of two pairs of ships in which the hull forms design only differed in the bow. Numerically, the dynamic pressure field diagrams for the different ships were analysed to study the pressure fluctuations, and the simulations were validated with the experimental results. From the study described above on sinkage, a strong relation between sinkage and the slenderness of ships was established leading to a predictive model of sinkage based on the slenderness of ships. By contrast, the bow shapes effect on sinkage suggested was rejected and it was concluded that the stern and the action of the propeller could have a key role in the sinkage of ships. Further research must be done to decrease CFD uncertainties at sinkage evaluation and to analyse the stern pressure fluctuations.

Study on Method for Avoiding Chatter Vibration by Changing Machine Tool Rigidity

Chatter vibration is a major problem in machining. At present, chatter vibration is avoided by changing the cutting conditions based on the stability limit diagram such that chatter vibration does not occur. However, changing the cutting conditions may reduce the productivity. The stability limit is estimated from the relationship between the dynamic characteristics of the machine tool and the cutting conditions. Therefore, we propose a method for avoiding chatter vibration by changing the machine tool rigidity. The dynamic characteristics of a desktop milling machine tool developed in a previous study can be changed by changing the tensile load of the brace bar attached on the frame. We report the transition of the dynamic characteristics and stability limit diagram with changes in the rigidity of the desktop machine tool, and confirm the presence or absence of chatter vibration through machining tests.

Stress fields in steel bridges

The paper deals with steel structures of road bridges. Multidimensional dynamic stress diagrams are suggested for steel road bridges. The analysis and quantitative conclusions are presented for the trouble-free operation of complex loaded structures. The paper describes the spatial distribution of mechanical stresses in buildings based on the obtained data on the operation under various loads and the statistical distribution of different points and zones of the object. Acoustic stress measurements are carried out during the bridge operation, and mathematical distributions are obtained for all measured points. It is shown that in determining the entire array of loads, a criterion can be identified for the trouble-free operation of bridge elements and the structure as a whole. Mathematical distributions are obtained or all measured points. The criterion parameter Χ 2 is introduced. It is found that the real three-dimensional distribution clearly describes the operation of various units and parts of steel road bridges. The findings confirm the proposed hypothesis about the possibility of such a description. It is noted that the real three-dimensional distribution well describes the work of various nodes, parts, parts of steel road bridges. The findings confirm our hypothesis about the possibility of such a description.

The Hierarchical Sequence Requirements of the H1 Subtype-Specific Noncoding Regions of Influenza A Virus.

The genome of influenza A virus consists of eight single-stranded viral RNA (vRNA) segments. The nonconserved noncoding regions (NCRs) at the 3' and 5' termini of each segment show extremely low divergence and mutation rate. They appear as segment specific among the eight segments and also subtype specific among different subtype-determinant hemagglutinin (HA) and neuraminidase (NA) segments. In order to acquire in-depth knowledge on the sequence requirements of the segment-specific or subtype-specific NCRs (ssNCRs), we, in the context of WSN (H1N1) reverse genetics, designed a virus random nucleotide selection assay (vRNSA) in which we generated pHW2000-HA plasmid libraries with random nucleotides in each grouped nucleotide positions in the 3' and 5' H1-ssNCRs, followed by virus rescue, serial passage, and deep sequencing. The resulting sequence logos present a visualized dynamic overview of the hierarchical sequence requirements of the 3' and 5' H1-ssNCRs. It showed that, in the process of continuous passage, the 3' H1-ssNCR, in general, stabilized more quickly than the 5' H1-ssNCR. The nucleotides close to the highly conserved 3' and 5' promoter regions showed higher sequence stringency than nucleotides away from the promoter regions. All stabilized sequences displayed a common feature of high A/U ratios. Especially with our mutational function analyses, we demonstrate that the 3' promoter-proximal nucleotides could cooperatively exert a direct effect on the transcription and replication of the HA segment. Together, these results provide in-depth knowledge for understanding the NCRs of influenza A virus. IMPORTANCE The segment-specific and subtype-specific nonconserved noncoding regions (ssNCRs) at both 3' and 5' ends of viral RNA segments of influenza A virus are largely conserved among the same segments of different viruses. However, the function-related sequence requirements of these ssNCRs remain unclear. In this study, through a novel self-designed vRNSA approach, we present a visualized dynamic overview diagram directly reflecting the hierarchical sequence requirements within and between the 3' and 5' H1-ssNCRs. The in-depth functional mutagenesis analyses further revealed that specific nucleotides in the 3' promoter-proximal region could cooperatively exert a direct effect on viral RNA transcription and replication. This work further advanced our knowledge in understanding the nonconserved noncoding regions of influenza A viruses.

Simulation and experimental investigation of kinematic characteristics of the wheeled in-pipe robot actuated by the unbalanced rotor

Mobile robotic systems are currently of significant interest due to the wide range of possible applications. Among a great variety of mobile robots, specific attention is paid to the wheeled ones. The main purpose of this research consists in substantiating the possibilities of improving the vibration-driven robot equipped with the unidirectionally rotating wheels. The methodology of the present study contains the development of the robot’s 3D-model in the SolidWorks software, constructing the simplified dynamic diagram of the robot’s oscillatory system, and developing its simulation model in the MapleSim software. The research results are obtained by numerical solving of the motion equations in the MapleSim software, by simulating the robot locomotion conditions in the SolidWorks software, and by conducting experiments. The results present the main kinematic characteristics of the robot motion under different operational conditions. The major scientific novelty of this paper consists in developing the improved design of the wheeled robot driven by the centrifugal (inertial) vibration exciter and substantiating its operational peculiarities. The obtained results can be effectively used while creating the production prototypes of mobile robotic systems, particularly those for cleaning the pipelines and monitoring (inspecting) their inner surfaces, welds, joints, couplings, etc.

Predicting the Response of RC Beam from a Drop-Weight Using Gene Expression Programming.

For structures and load-bearing beams under extreme impact loading, the prediction of the transmitted peak impact force is the most challenging task. Available numerical and soft computing-based methods for finding peak impact force are not very accurate. Therefore, a simple and user-friendly predictive model is constructed from a database containing 126 impact force experiments of the simply supported RC beams. The proposed model is developed using gene expression programming (GEP) that includes the effect of the impact velocity and the impactor weight. Also identified are other influencing factors that have been overlooked in the existing soft computing models, such as concrete compressive strength, the shear span to depth ratio, and the tensile reinforcement quantity and strength. This allows the proposed model to overcome several inconsistencies and difficulties residing in the existing models. A statistical study has been conducted to examine the adequacy of the proposed model compared to existing models. Additionally, a numerical confirmation of the empirical model of the peak impact force is obtained by reference to 3D finite element simulation in ABAQUS. Finally, the proposed model is employed to predict the dynamic shear force and bending moment diagrams, thus rendering it ideal for practical application.

Design and simulation of a silicon-based hybrid integrated optical gyroscope system

By combining a silicon-based lithium niobate modulator and a silicon-based Si3N4 resonator with silicon-based photonics technology, a highly systematic design of a hybrid integrated optical gyroscope with enhanced reciprocity sensitivity and a dual micro-ring structure is proposed for the first time in this paper. The relationship between the device’s structural parameters and optical performance is also analyzed by constructing a complete simulation link, which provides a theoretical design reference to improve the system’s sensitivity. When the wavelength is 1550 nm, the conversion frequency of the dual-ring optical path is 50 MHz, the coupling coefficient is 0.2, and the radius R is 1000 μm, the quality factor of the silicon-based Si3N4 resonator is 2.58 × 105, which is 1.58 times that of the silicon-on-insulator resonator. Moreover, the effective number of times the light travels around the ring before leaving the micro-ring is 5.93, which is 1.62 times that of the silicon-on-insulator resonator. The work fits the gyro dynamic output diagram, and solves the problem of low sensitivity at low speed by setting the phase offset. This results provide a basis for the further optimization of design and chip processing of the integrated optical gyroscope.

A qualitative system dynamics perspective on the contribution of information technology credibility towards business and information technology alignment

Purpose: The dynamic interdependence between the deployment of technological assets and organisational performance remains a challenge for modern enterprises. Organisations reinforce competitiveness and improve performance when business activities and information technology (IT) efforts are aligned. The credibility of the IT organisation is an important influence on alignment. This research guides managers and directs future research to improve IT credibility.Design/methodology/approach: Interviews with senior leaders about factors influencing IT credibility provided rich data for analyses. The dynamic complexity of creating a credible IT function to ensure alignment was captured using qualitative system dynamic diagrams. A causal loop diagram was constructed to identify feedback loops and leverage points.Findings: The analysis confirms the impact of three factors identified by prior research. It provides a new perspective on portfolio-level IT governance’s contribution to establishing credibility. The value of using past failure to develop credibility through ownership and resolution emerged from the analysis.Practical implications: The results provide guidelines to improve the IT organisation’s credibility to improve business and IT alignment. Leverage points to improve credibility are provided, and research into resolving past failure as a mechanism to success is suggested.Originality/value: While most of the extant literature focused on static alignment factors, causal loop diagrams provided insight into IT credibility’s systemic nature. A new factor (resolving past failure), a new perspective (portfolio level governance), and confirmation of existing factors and identifying leverage points contribute to practice and science.