Static State Research Articles

Efficient response analysis of the cable of offshore wind turbine at static state: Hybrid of perturbation method and grey wolf optimization

Efficient response analysis of the cable of offshore wind turbine at static state: Hybrid of perturbation method and grey wolf optimization

Speed Tuning of the Formation/Dissociation of a Metallorotaxane

AbstractSwitching between the formation/dissociation of rotaxanes is important to control the function of various types of rotaxane‐based materials. We have developed a convenient and simple strategy, the so‐called “accelerator addition”, to make a static rotaxane dynamic without apparently affecting the chemical structure. As an interlocked molecule that enables tuning of the formation/dissociation speed, a metallorotaxane was quantitatively generated by the complexation of a triptycene‐based dumbbell‐shaped mononuclear complex, [PdL2]2+ (L=2,3‐diaminotriptycene), with 27C9. As a result of the inertness of the Pd2+‐based coordination structure, the metallorotaxane was slowly formed (the static state). This rotaxane formation was accelerated 27 times simply by adding Br− as an accelerator (the dynamic state). A similar drastic acceleration was also demonstrated during the dissociation process when Cs+ was added to the metallorotaxane to form the free axle [PdL2]2+ and the 27C9‐Cs+ complex.

Linear SV Plot Ananlysis in Steady State and Transient State to Explore Fluorescence Quenching of Coumarin Derivative by Aniline

Static and transient state analysis related to fluorescence quenching of heterocyclic compound namely 3-Hydroxy-3-[2-oxo-2-(3-oxo-3H-benzo[f]chromen-2-yl)-ethyl]-1,3-dihydro-indol-2-one [3HBCD] in Toluene (nonpolar) and Butanol (polar protic) reveals the play of material diffusion in quenching mechanism. Time resolved method is used in Toluene a nonpolar solvent to further support the theory of material diffusion. Aniline is used as quencher to carry out the quenching studies. In both steady and transient state linear SV plots are observed with intercept ≈ 1. Correlation in the activation energy in both study state and transient state (Ea and E’a) suggests efficient quenching. Also calculated values of p (or p’) and the activation energies points that material diffusion has predominant role in quenching. This study help engineer the structure of new family of coumarin drugs with selective sensitivity which is of utmost importance in the field of chemistry and pharmaceutical industry.

A Robust Method for Distribution System State Estimation with Predator-Prey Brain Storm Optimization

In this paper, a new method is proposed for distribution system static state estimation with low redundant measurements. It is different from transmission system static state estimation because the distribution system static state estimation has low redundancy of measurements while the transmission system static state estimation has enough redundancy. This paper makes use of the nest structure of DistFlow of the distribution system power flow calculation to transform the formulation into evaluating the state variable vector at distribution substations. In other words, the distribution state estimation problem may be expressed as an optimization problem. As the optimization method, PPBSO (Predator-Prey Brain Storm Optimization) of evolutionary computation is proposed to solve the problem. The proposed method is successfully applied to a sample system.

Electronic steering of a mobile robot for wall following and obstacle avoidance

Robots, including mobile robots, provide many services in military, industrial and space applications. They shorten time, reduce expenses, and reduce danger to humans in places that may pose a threat to human life. Although the use of mobile robots in civil applications is few, it is in an increasing growth. Such as using it to transport goods in small neighbourhoods or to clean streets. Most of the algorithms in robot navigation are wall or path tracking through conventional sensors directly or through optical or physical sensors. Mobile robots are of different types, and these types depend on the number of wheels and the way they are distributed and directed to add to the robot the number of degrees of freedom. One of the problems facing the mobile robot is the multitasking of self-driving, such as tracking a path and discovering and avoiding an obstacle. Multi-tasking caused confusion for the mobile robot, as its processing of one task in tracking the wall makes it deal with the distance from the wall as a reference point to keep it in the alignment position regardless of the speed of its wheels or the angle of deviation of the wall from it. This process requires the provision of many additional data to enable it to perform the task. This research presents the design and construction of a mobile robot that tracks the wall, analyses the obstacles, and then takes action. The work is to build a mathematical model and calculate the mathematical effects on all the available information from the sensors measuring distance and freedom, speed and real time information. The idea entered on separating the robot programmatically into two parts. The first part is a mobile robot that has electronic guidance based on speed sensors connected to the front wheels, which are included as part of a closed control system to control the speed of the wheels accurately. At the end, this robot can walk straight for a distance that can be determined and implement deviations at a specific angle with the given value, as well as it can walk in the form of a square, triangle, and circular as well as it can walk on an inclined road up or down without decreasing or increasing its speed. This method makes the mobile robot more flexible. As for the second part, it is measuring the angle of deflection of the wall and exploring obstacles by measuring the distances surrounding the robot at an angle of 90 degrees. The deflection angle of the wall is calculated using an algorithm that depends on calculating the distance between two points within the path of the robot. These two points have information about the measured distance between the wall and the robot, the speed of the robot, and time. Through this information, the deflection angle of the wall is calculated relative to the mobile robot. The wheel speed control algorithms and the electronic steering algorithm were implemented on a processor connected to the wheel marketer and considered the first part, then algorithms were implemented to calculate the wall deviation measurement and analyse the obstacles and considered the second part. Information was exchanged between the two processors to carry out all the tasks, as the first processor provides information about the speed of the wheels and time, and through which the second processor can calculate all the distances that it wants to calculate as virtual points. The most important conclusions that emerged through practical experience are the effect of the distribution of sensors on the robot’s structure and the presence of a time difference in the wheels’ transition from one speed to another and even from a static state to a moving state, despite its being proven around the reference point, and this required solving it programmatically in equalizing this timing to ensure that the robot remains in Forward direction when changing its speed. The project has proven high accuracy with high information management.

Study on the Hydrodynamic Performance of a Countercurrent Total Spray Tray under Sloshing Conditions

In this paper, a new type of total spray tray (TST) with gas–liquid countercurrent contact is proposed to solve the problem of slight operation flexibility and poor sloshing resistance in towers under offshore conditions. Its hydrodynamic performance indicators, such as pressure drop, weeping, entrainment, and liquid level unevenness, were experimentally studied under rolling motion. A tower with an inner diameter of 400 mm and tray spacing of 350 mm was installed on a sloshing platform to simulate offshore conditions. The experimental results show that the rolling motion affected the hydrodynamic performance of the tray under experimental conditions. When the rolling amplitude did not exceed 4°, the degree of fluctuation of the hydrodynamic performance was small, and the tray could still work stably. With increasing rolling amplitude, the TST wet plate pressure drop, weeping, and liquid level unevenness fluctuations also increased. When the rolling amplitude reached 7°, the maximum fluctuation of the wet plate pressure drop was 8.9% compared to that in the static state, and the plate hole kinetic energy factor, as the TST reached the lower limit of weeping, increased rapidly from 6.2 at rest to 7.8 under the experimental conditions. It can be seen that the TST still exhibits good hydrodynamic performance under rolling motion.

Research on methane hydrate formation in porous media with gas–water two-phase flow

The study of hydrate formation in porous media is crucial for the efficient production of natural gas hydrate. Current research on gas hydrate formation in porous media has primarily focused on the static state. A prediction model of hydrate formation under the condition of gas–water two-phase flow was established by combining the heat transfer and gas–water two-phase flow mechanisms in porous media. Methane hydrate formation in quartz sand was experimentally investigated under a gas–water two-phase flow. The results revealed an obvious pressure difference with hydrate formation at different positions; the pressure difference increased with time, which can be used as an important basis to assess the distribution of flow obstacles in porous media. COMSOL Multiphysics was used to solve the proposed model, and the accuracy of the model prediction results was verified using the experimental data. Further, the hydrate formation process and evolution law in the experiment were simulated and inverted. Flow parameters, such as pressure, hydrate saturation, and water saturation, presumably exhibit non-uniform distributions with the formation of hydrates in porous media. The longer the time, the more distinct the non-uniform distribution of the aforementioned parameters and the higher the risk of flow obstacles in porous media. This study provides an important theoretical basis for the efficient development of natural gas hydrate in the future.

Mechanism analysis of hysteretic aerodynamic characteristics on variable-sweep wings

Variable-sweep wings have large shape-changing capabilities and wide flight envelops, which are considered as one of the most promising directions for intelligent morphing UAVs. Aerodynamic investigations always focus on several static states in the varying sweep process, which ignore the unsteady aerodynamic characteristics. However, deviations to static aerodynamic forces are inevitably caused by dynamic sweep motion. In this work, first, unsteady aerodynamic characteristics on a typical variable-sweep UAV with large aspect ratio were analyzed. Then, deep mechanism of unsteady aerodynamic characteristics in the varying sweep process was studied. Finally, numerical simulation method integrated with structured moving overset grids was applied to solve the unsteady fluid of varying sweep process. The simulation results of a sweep forward-backward circle show a distinct dynamic hysteresis loop surrounding the static data for the aerodynamic forces. Compared with the static lift coefficients , at the same sweep angles, dynamic lift coefficient in sweep forward process are all smaller, while dynamic sweep backward lift coefficient are all larger. In addition, dynamic deviations to static lift coefficient are positively related with the varying sweep speeds. Mechanism study on the unsteady aerodynamic characteristics indicates that three key factors lead to the dynamic hysteresis loop in varying sweep process. They are the effects of additional velocity caused by varying sweep motion, the effects of flow hysteresis and viscosity. The additional velocity induced by sweep motion affects the transversal flow direction along the wing and the effective angle of attack at the airfoil profile. The physical properties of flow, the hysteresis and viscosity affect the unsteady aerodynamic characteristics by flow separation and induced vortexes.

Expression profile of microRNA secreted by rat condylar chondrocytes under tensile stress

Objective: To preliminarily explore the mechanism of tensile stress regulating endochondral osteogenesis of condyle by analyzing the expression profiles of significantly different microRNAs (miRNAs) in exosomes of rat mandibular condylar chondrocytes (MCC) under quiescent and cyclic tensile strain (CTS) conditions. Methods: Rat condylar chondrocytes were cultured under static and CTS conditions respectively (10 SD rats, male, 2 weeks old), and exosomes were extracted. The two groups of exosomes were named as control group and CTS group respectively. The differential expression miRNAs were screened by high-throughput sequencing. Bioinformatics analysis and prediction of target genes related to osteogenesis were performed by TargetScan and miRanda website. Results: The exosomes of rat condylar chondrocytes cultured under tensile stress showed a "double concave disc" monolayer membrane structure, the expression of CD9 and CD81 were positive, and the particle size distribution accorded with the characteristics of exosomes, which was consistent with that of static cultured rat condylar chondrocytes. A total of 85 miRNAs with significantly different expression were detected by high-throughput sequencing (P<0.05). The main biological processes and molecular functions of differential miRNAs were biological processes and protein binding, respectively. Kyoto Encyclopedia of Genes and Genomes (KEGG) database pathway enrichment analysis showed that there was significant enrichment in mammalian target of rapamycin (mTOR) signal pathway. The candidate target genes of miR-199a-5p include bone morphogenetic protein 3 (BMP3), endothelin converting enzyme 1, and miR-186-5p may target Smad8 and BMP3 to exert osteogenesis-related functions. Conclusions: Compared with static state, tensile stress stimulation can change the expression of miRNAs such as miR-199a-5p, miR-186-5p in the exocrine body of rat condylar chondrocytes, which can be considered as a mean to regulate the application potential of the exosomes.

Oscillatory and chaotic regimes of patterns and dark cavity solitons in cavities displaying EIT: Static multihead dual chimera states

Oscillating and chaotic regimes of honeycomb patterns and dark cavity solitons are studied in a cavity displaying electromagnetically induced transparency. Considering a three-level atomic system in a Λ configuration, transition to chaotically oscillating honeycombs is numerically investigated and their dynamical behavior is detailed for different control parameter values. We show that a branch of oscillating dark cavity solitons coexists with the honeycomb patterns. These oscillating cavity solitons are studied individually and in mutual interaction. In particular, it is shown that mutually coherent oscillating dark cavity solitons can be obtained by choosing an appropriate separation distance. Finally, we introduce a novel regime of chimera states consisting of a multitude of identically and non-locally coupled dark cavity solitons in which regions of in-phase and anti-phase coherence separated by incoherent areas coexist and are stationary. We discuss the unique features of these structures and categorize them as static multihead dual chimera states. We believe that this is the first time that such chimeric states are reported in a photonic system hosting oscillating and chaotic structures.

Pritchard on ignorance and normativity

There is a debate on the nature of ignorance in contemporary epistemology. The standard view holds that ignorance is the lack of knowledge, while the new view contends that ignorance is the lack of true belief. Rather than taking a side in this dispute, Pritchard recently offers a new proposal according to which ignorance essentially involves not just the absence of a certain epistemic good, but also an intellectual failing of inquiry. We argue that Pritchard’s new proposal advances the discussion of ignorance by incorporating insight from virtue epistemology, and hence the normative dimension of ignorance is properly noticed. Crucially, ignorance is no longer a mere static cognitive state, but also reflects the quality of inquiry and inquirers’ obligations. However, the new proposal faces two problems. First, current formulation is incomplete so that it cannot ground the epistemic blame that Pritchard requires. More details must be filled in. Second, his view would label all ignorance as normatively negative, and therefore locutions such as virtuous ignorance, blameless ignorance and the positive value of ignorance would be wrong.

КОНЦЕПЦІЇ КОНКУРЕНЦІЇ ЯК КЛЮЧОВА СКЛАДОВА НАУКОВОГО ЗАБЕЗПЕЧЕННЯ ФОРМУВАННЯ КОНКУРЕНТОСПРОМОЖНОСТІ ПРОДУКЦІЇ ТВАРИННИЦТВА

The scientific article has proved the importance of researching the concepts of competition within the framework of ensuring the formation of the competitiveness of Ukrainian livestock and Ukrainian livestock products. Five basic concepts of competition have been defined: “Contest as a static state,” “Competition as a process of rivalry,” “Porter’s diamond,” RAM, and IIT. The following basic concepts of competition have been theoretically characterized by a set of features, such as levels of using the concept (world, international, national, industry/regional, and individual enterprise/individual household); enterprises that can use the concept appropriately; behavior and activities of competitors; consumer behavior; the behavior of other market participants; key terms of using the concept (critical terms of the competition); a key criterion for the formation of competitiveness; possibilities of implementation into animal husbandry (macro – national level; meso – branch and regional level; micro – individual enterprises and households). In addition, the positive and negative aspects of using each of the five defined concepts of competition to form the competitiveness of Ukrainian livestock and Ukrainian livestock products have been determined. It has been proved that the concept of competition, “Competition as a static state,” can be used, with certain limitations, in animal husbandry at the macro-, meso-, and micro levels; “Competition as a process of rivalry” can be used in animal husbandry at the macro, meso, and micro levels; “Porter’s diamond” can be used in animal husbandry mainly at the meso level; RAM can be used in animal husbandry mainly at the micro level; and IIT can be used in animal husbandry mainly at the macro level. The limitation of the use of each of the researched concepts of competition in terms of the formation of the competitiveness of Ukrainian livestock farming and products of Ukrainian livestock breeding has also been noted. It requires a balanced, appropriate, and thorough use of concepts at the macro-, meso-, and micro-levels of the modern economic systems functioning.

“Rede hit sofft”: John Audelay's Practice of Care

“Rede hit sofft”: John Audelay's Practice of Care

Influence of Water on Anchor Plate Behavior in Sandy Soil with and Without Improvement

Plate anchors are one of the most common types of ground anchors used in foundation systems, as they transfer loads from the foundation to the soil to prevent overturning the foundation and overcome the forces that could threaten the integrity of the structure. The present work concerns the study of the combined effects among the behavior of the anchor plate in sandy soil with and without water presence as a static state at a different head level (h=15, 30, and 40 cm) above the base of the anchor plate and for two states of the soil with improvement by geogrid at various location and without improvement. The soil sample was brought from AL-Nidaa district in the city of AL-Najaf (Iraq). The highest value of the ultimate uplift capacity is observed when the geogrid layer is adjacent to the anchor plate for dry and submerged cases of the soil. The negative effect of the presence of the geogrid layer appears when the water table level rises above the ground surface level.

A WiFi Indoor Location Tracking Algorithm Based on Improved Weighted K Nearest Neighbors and Kalman Filter

The Weighted K Nearest Neighbor (WKNN) algorithm is a widely adopted lightweight methodology for indoor WiFi positioning based on location fingerprinting. Nonetheless, it suffers from the disadvantage of a fixed K value and susceptibility to incorrect reference point matching. To address this issue, we present a novel algorithm in this paper, referred to as Static Continuous Statistical Characteristics-Soft Range Limited-Self-Adaptive WKNN (SCSC-SRL-SAWKNN). Our algorithm not only takes into account location tracking in the motion state but also exploits the continuous statistical features of extended periods of inactivity to enhance localization. In the motion state, we initially employ the adaptive WKNN (SAWKNN) algorithm to determine the optimal K value, followed by the employment of the Soft Range Limited KNN (SR-KNN) algorithm to identify the correct reference point and ultimately estimate the position. When a prolonged stationary state is detected, we first utilize the moving window method to obtain a more stable position fingerprint (SCSC), and then proceed with the positioning process in the same motion state. Ultimately, we use Kalman filter to generate the location trajectory. Our experimental findings demonstrate that the proposed SCSC-SRL-SAWKNN algorithm outperforms traditional WKNN, SAWKNN, and SRL-KNN techniques in terms of localization accuracy and location trajectory. Specifically, the localization accuracy of our algorithm is 56.7% and 36.6% higher than that of traditional WKNN in the static state and overall situation, respectively.

Experimental investigation on the effect of vertical vibration on heat transfer performance of two-phase loop thermosyphons with different diameters

The two-phase loop thermosyphon (TPLT) is generally a technique used in conjunc?tion with a fan when cooling an electronic chip to enhance the cooling effect. In this context, the TPLT heat transfer efficiency is directly affected by the vibration caused by the associated fan. In this paper, the heat transfer performances of TPLT with diameters of 4 mm, 6 mm, and 8 mm were experimentally investigated under a heat?ing power capacity ranging from 40-400 W, a filling ratio of 40-70%, and a 30 m/s2 35 Hz vertical reciprocating vibration. The heat transfer performance of the TPLT is compared to the case of operation under the same working conditions in a static state. The influence of the vibration state caused by the fan rotation on the heat transfer performance of TPLT with different diameters is analyzed and discussed. The obtained results indicated that vertical vibration does not change the trend of TPLT heat transfer performance with the corresponding heating power capacity un?der each pipe diameter. On the other hand, it was found that the vibration enhances or inhibits the heat transfer characteristics of TPLT, affected by the pipe diameter, the heating power capacity, and the liquid filling ratio.

Nucleation enhancement by energy dissipation with the collision of a supercooled water droplet

Lack of knowledge on nucleation with mechanical disturbances hinders researchers in understanding the anti-icing properties of superhydrophobic surfaces. In this research, experiments are designed to observe the freezing process of a supercooled water droplet at −14 °C with different levels of external disturbances by changing the impact velocity, and the nucleation rates are statistically analyzed. It is found that compared with the static state, the nucleation rates of droplets during the collision increase by three and five orders of magnitude on the hydrophilic epoxy resin and superhydrophobic polytetrafluoroethylene (PTFE) surfaces, respectively, which leads to a much higher instantaneous nucleation rate on the superhydrophobic surface than on the hydrophilic surface. Then, the mechanical energy dissipation during the impact is analyzed. The logarithm of the nucleation rate is approximately linear in relation to the logarithm of the average energy dissipation rate, while the nucleation rate of the rough PTFE surface increases more rapidly than that of the other smooth surface. Finally, the effect of the energy dissipation on the nucleation energy barrier is discussed theoretically and an impact-nucleation model is proposed, which drives the reconsideration of the design of a superhydrophobic anti-icing coating.

Research on automatic early warning of UAV attitude abnormal state based on MEMS sensor

The Unmanned Aerial Vehicle's (UAV) attitude control is crucial to the success of the mission. On the basis of this, the paper suggests a paradigm for autonomous early warning of improper UAV attitude based on MEMS sensors. To obtain early warning of anomalous UAV attitude, the model solves UAV attitude using the quaternion approach and employs a fading Kalman filter to correct for MEMS gyroscope inaccuracy. The simulation test demonstrates that in the static state, the errors of the drone's pitch angle and roll angle are within 0.2°, and the heading angle error is about 0.5°. In the high manoeuvring state, the errors of the UAV's pitch angle and roll angle are all within 0.5°, and the mean value of the heading angle error is also controlled within 2°. The experiment achieves high-precision automated warning of aberrant attitude by filtering the fading Kalman filter to correct the random error of the UAV gyroscope. It also increases the precision with which human motion is measured. The suggested approach promotes the growth of the UAV sector.

Quantum state and detector tomography with known rank

Quantum state tomography and quantum detector tomography are two main problems in quantum system identification. In this paper, we study state tomography and detector tomography with prior knowledge about the true rank of the unknown state/detector. In this case, we propose a sufficient condition for static (non-adaptive) tomography algorithms to achieve the optimal infidelity scaling O(1/N) on the number of state copies N. Then we present two examples of such static quantum state tomography and quantum detector tomography algorithms. Numerical examples demonstrate the effectiveness of our algorithms.

Computational mesoscale framework for biological clustering and fractal aggregation.

Hierarchical clustering due to diffusion and reaction is a widespread occurrence in natural phenomena, displaying fractal behavior with non-integer size scaling. The study of this phenomenon has garnered interest in both biological systems such as morphogenesis and blood clotting, and synthetic systems such as colloids and polymers. The modeling of biological clustering can be difficult, as it can occur on a variety of scales and involve multiple mechanisms, necessitating the use of various methods to capture its behavior. Here, we propose a novel framework, the generalized-mesoscale-clustering (GMC), for the study of complex hierarchical clustering phenomena in biological systems. The GMC framework incorporates the effects of hydrodynamic interactions, bonding, and surface tension, and allows for the analysis of both static and dynamic states of cluster development. The framework is applied to a range of biological clustering mechanisms, with a focus on blood-related clustering from fibrin network formation to platelet aggregation. Our study highlights the importance of a comprehensive characterization of the structural properties of the cluster, including fractal dimension, pore-scale diffusion, initiation time, and consolidation time, in fully understanding the behavior of biological clustering systems. The GMC framework also provides the potential to investigate the temporal evolution and mechanical properties of the clusters by tracking bond density and including hydrodynamic interactions.