Scalable and Secure Gradient Smart Dempster Shafer Reputation for Development of Smart Cities

Over the last decade, blockchain has been considered an encouraging solution to secure distributed ledgers. Moreover, with the introduction of a pseudonymous payment method without a centralized database or authoritative person, blockchain has also evolved as the future generation for online payment system. However, with the eruption of a large scale database, scalability has also become a demanding issue. In addition to the obstacle mentioned above, challenges like security and scalability stop accelerated adjustments for the development of smart cities. Without directing this essential scalability and privacy issue, such an encouraging method may not help develop smart cities. This paper bestows a measure to analyze both scalability and security aspects of existing blockchain methods with applications of smart city networks. The proposed method is known as Gradient Smart Load Balancer and Blockchain Dempster Shafer Reputation (GSLB-BDSR). Gradient Smart Load Balancer is designed so that even though with the increase in the number of participating sensors, the load is said to balance by applying gradient function, therefore ensuring scalability. Next, to cover the security aspect, with the aid of scalable blocks in the blockchain network, a Blockchain Dempster Shafer Reputation model is proposed. Evaluation outcomes of proposed security solutions outperform conventional solutions.

Fracture Behavior of Bio-Inspired Functionally Graded Soft–Hard Composites Made by Multi-Material 3D Printing: The Case of Colinear Cracks

The functional gradient is a concept often occurring in nature. This concept can be implemented in the design and fabrication of advanced materials with specific functionalities and properties. Functionally graded materials (FGMs) can effectively eliminate the interface problems in extremely hard–soft connections, and, thus, have numerous and diverse applications in high-tech industries, such as those in biomedical and aerospace fields. Here, using voxel-based multi-material additive manufacturing (AM, = 3D printing) techniques, which works on the basis of material jetting, we studied the fracture behavior of functionally graded soft–hard composites with a pre-existing crack colinear with the gradient direction. We designed, additively manufactured, and mechanically tested the two main types of functionally graded composites, namely, composites with step-wise and continuous gradients. In addition, we changed the length of the transition zone between the hard and soft materials such that it covered 5%, 25%, 50%, or 100% of the width (W) of the specimens. The results showed that except for the fracture strain, the fracture properties of the graded specimens decreased as the length of the transition zone increased. Additionally, it was found that specimens with abrupt hard–soft transitions have significantly better fracture properties than those with continuous gradients. Among the composites with gradients, those with step-wise gradients showed a slightly better fracture resistance compared to those with continuous gradients. In contrast, FGMs with continuous gradients showed higher values of elastic stiffness and fracture energy, which makes each gradient function suitable for different loading scenarios. Moreover, regardless of the gradient function used in the design of the specimens, decreasing the length of the transition zone from 100%W to 5%W increased the fracture resistance of FGMs. We discuss the important underlying fracture mechanisms using data collected from digital image correlation (DIC), digital image microscopy, and scanning electron microscopy (SEM), which were used to analyze the fracture surface.

Large eddy simulation of energy gradient field in a centrifugal pump impeller

Large eddy simulation of the fluid flow in a centrifugal pump impeller is conducted at design load and quarter load, and the energy gradient field is analyzed to reveal the behavior of internal flow. A universal equation for calculating the energy gradient function, which is defined as the ratio of energy increase (transversal gradient of the mechanical energy gradient) to energy loss (stream-wise gradient of the work done by shear stress), is adopted. Research results show that positive and negative 0.3 for the logarithm of energy gradient function are critical values that reflect dominant energy increase and dominant energy loss, respectively. The large eddy simulation results indicate that the magnitude and shape of energy gradient field are affected by turbulent fluctuation. The energy gradient field in the impeller at mid-height has more small-scale features than those in the impeller at zero and one heights. The regions of dominant energy increase and dominant energy loss are highly distinct at both design load and quarter load. In some large areas, neither dominant energy increase nor dominant energy loss is observed at quarter load in the impeller passage. These results, which are mainly attributed to a highly separated flow, are not evident at design load. The region of dominant energy increase at design load is larger than that at quarter load, particularly close to the volute. The magnitude of mean logarithm of energy gradient function at quarter load is evidently smaller than that at design load, but its value remains higher than 1.0.

Capitalist Income and Hierarchical Power

This paper offers a new approach to the study of capitalist income. Building on the 'capital as power' framework, I propose that capitalists earn their income not from any productive asset, but from the legal right to command a corporate hierarchy. In short, I hypothesize that capitalist income stems from hierarchical power. Based on this thinking, I hypothesize that the capitalist fraction of an individual's income is a gradient function of hierarchical power (which I define as the number of subordinates under one's control). Using data from US CEOs, I find evidence that this is true. Furthermore, a hierarchical model of the United States that generalizes this data accurately reproduces many aspects of the US distribution of capitalist income, including the relation between income size and capitalist income fraction. This evidence suggests that the ownership structure of US society is closely linked to the hierarchical structure of firms. This has important implications for the study of income distribution.

Stability of boundary layer flow based on energy gradient theory

The flow of the laminar boundary layer on a flat plate is studied with the simulation of Navier–Stokes equations. The mechanisms of flow instability at external edge of the boundary layer and near the wall are analyzed using the energy gradient theory. The simulation results show that there is an overshoot on the velocity profile at the external edge of the boundary layer. At this overshoot, the energy gradient function is very large which results in instability according to the energy gradient theory. It is found that the transverse gradient of the total mechanical energy is responsible for the instability at the external edge of the boundary layer, which induces the entrainment of external flow into the boundary layer. Within the boundary layer, there is a maximum of the energy gradient function near the wall, which leads to intensive flow instability near the wall and contributes to the generation of turbulence.

On Hydrodynamic Stability of Dean Flow by Using Energy Gradient Methods

ABSTRACTIn the present paper, we investigate the hydrodynamic instability of Dean flow under different Dean numbers ranging from 1 to 2500, curvature ratios from 0.0001 up to 1000 and temperatures ranging from 273.15 K to 373.15 K. To study of fluid flow instability, analytical velocity profiles under intended conditions and energy gradient function K in the energy gradient method are evaluated. The results of present study show that, as the curvature ratio increases the flow becomes more stable. Moreover, no regular and significant effects on the energy gradient function K were achieved by increasing of temperatures. We found that, the origin of instability in the entire flow field is located on the inner wall of the parallel curved walls, especially for larger curvature ratios. We also reported the critical value of the energy gradient function K for the onset of instability corresponding to the critical Dean number.