Exact Controllability Research Articles

Revolutionizing healthcare materials: Innovations in processing, advancements, and challenges for enhanced medical device integration and performance

Cutting-edge materials have transformed the fabrication of medical devices and implants. However, the processing used to create these materials impacts their mechanical, physical, and biological characteristics, preventing effective integration. This study is intended to provide a detailed analysis of healthcare materials processing techniques, stressing healthcare-specific material requirements, such as biocompatibility, mechanical strength, corrosion resistance, stabilizability, and bioactivity, followed by classifying these processing methods as “ordinary” and “edge-cutting” methods. The consequences of each processing on the material, as well as the benefits, drawbacks, and recent developments of each technique, are also aimed to be concluded. The study also aimed to explore how process factors affect product qualities. The articles are collected from the Scopus and Web of Science databases using the search strings “Advance Material,” “Material Processing,” “Healthcare,” and “HealthCare Application.” The assessment of the selected literature has been done in accordance with the objectives. The assessment emphasizes quality assurance and regulatory compliance by stressing the need for quality assurance, characterization, and testing for medical devices and implants. Processes such as polishing, etching, and coatings improve biocompatibility and reduce infection risk, according to the findings. It was also concluded that cutting-edge processing methods such as additive manufacturing (3D printing) and electrospinning provide exact control over material composition, structure, and porosity, making them ideal for many clinical applications.

Size Reduction to Enhance Crystal-to-Liquid Phase Transition Induced by E-to-Z Photoisomerization Based on Molecular Crystals of Phenylbutadiene Ester.

Harnessing the photoinduced phase transitions in organic crystals, especially the changes in shape and structure across various dimensions, offers a fascinating avenue for exact spatiotemporal control, which is crucial for developing future smart devices. In our study, we report a new photoactive molecular crystal made from (E)-2-(3-phenyl-allylidene)malonate ((E)-PADM). When exposed to ultraviolet (UV) light at 365 nm, this compound experiences an E-to-Z photoisomerization in liquid solution and a crystal-to-liquid phase transition in solid crystals. Remarkably, nanoscopic crystalline rods boost their melting rate and degree compared to bulk crystals, indicating that miniaturization enhances the photoinduced melting effect. Our results demonstrate a simple approach to rapidly drive molecular crystals into liquids via photochemical reactions and phase transitions.

Coupled wave equations with monotone nonlinearity: existence of solution and controllability results

In this manuscript, we investigate a coupled semilinear system characterised by two wave equations in which the nonlinear function satisfies the monotonicity condition. Initially, the existence of a solution is established through the application of Schauder's fixed point theorem. Thereafter, the results pertaining to the exact controllability are demonstrated for two different cases by establishing a relation between the reachable set of the semilinear system and its linear counterpart. Additionally, an illustrative example is provided to showcase the practical relevance of our theoretical findings.

Sintering parameter optimization by inverse analysis in direct metal deposition of Inconel 718

PurposeThe net power delivered to the surface of parts (i.e. the actual heat flux) is a key parameter in the laser melting process and its exact control has a great impact on the numerical solutions. In this paper, the impact of laser additive manufacturing parameters including laser power, scanning speed and powder injection rate on thermal efficiency, net power delivered to the part and power loss due to powder flow has been investigated.Design/methodology/approachThe response surface method was applied to measure the net laser power in laser deposited Inconel 718 using k-type thermocouples. The temperature history obtained by thermocouples was used to calculate the net power delivered by inverse analysis method. The applied model is Rosenthal's optimized model, in which all the thermal properties of the material are considered to vary with temperature.FindingsThe results indicated that the thermal efficiency, power delivered to the part and power loss can be optimized simultaneously at laser power of 400 W, scanning speed of 2 mm/s and powder injection rate of 200 mg/s. The microstructure analysis indicated that a high-quality sample without microstructural defects was formed under optimal condition of parameters. Moreover, the primary dendrite arm spacing for the optimal sample was higher than that obtained for other samples.Originality/valueThe novelty of this research summarized as follows: Prediction of the thermal efficiency and power loss during the laser metal deposition of Inconel 718 superalloy using the inverse analysis. Finding the optimal values of thermal efficiency, power delivered to the surface and power loss in the laser metal deposition of Inconel 718 superalloy. Investigating the effect of laser power, powder injection rate and scanning speed on the thermal efficiency and power loss of Inconel 718 superalloy during the laser metal deposition.

Approximation theorem for the Kawahara operator and its application in the control theory

AbstractControl properties of the Kawahara equation are considered when the equation is posed on an unbounded domain. Precisely, the paper's main results are related to an approximation theorem that ensures the exact (internal) controllability in . Following [23], the problem is reduced to prove an approximate theorem which is achieved thanks to a global Carleman estimate for the Kawahara operator.

On the Exact Boundary Controllability of Semilinear Wave Equations

On the Exact Boundary Controllability of Semilinear Wave Equations

Optimal Neumann control of the wave equation with L 1-control cost: the finite-time turnpike property

The finite-time turnpike property describes a situation where the optimal state reaches a steady state after finite time. The steady state is a solution of a static optimal control problem. We study an optimal control problem where the objective functional is the sum of an L 1 -norm control cost with a weight γ > 0 and a differentiable tracking term. We consider a vibrating string with homogeneous Dirichlet conditions at one end and Neumann control action at the other end. The tracking term is defined by the squared L 2 -norm of a non-collocated Neumann-observation. We show that the problem has a unique solution and that due to the non-smoothness of the L 1 -norm for sufficiently large T the optimal state reaches the desired state after a finite time that is equal to the minimal time where exact controllability holds. We also study the effect of smoothing of the control cost on the structure of the optimal control and show that the finite-time turnpike property also holds in the smoothing limit in a strong L 2 -sense.

Stackelberg exact controllability for the Boussinesq system

Stackelberg exact controllability for the Boussinesq system

Recent Advances in Non-Ti MXenes: Synthesis, Properties, and Novel Applications.

One of the most fascinating 2D nanomaterials (NMs) ever found is various members of MXene family. Among them, the titanium-based MXenes, with more than 70% of publication-related investigations, are comparatively well studied, producing fundamental foundation for the 2D MXene family members with flexible properties, familiar with a variety of advanced novel technological applications. Nonetheless, there are still more candidates among transitional metals (TMs) that can function as MXene NMs in ways that go well beyond those that are now recognized. Systematized details of the preparations, characteristics, limitations, significant discoveries, and uses of the novel M-based MXenes (M-MXenes), where M stands for non-Ti TMs (M=Sc, V, Cr, Y, Zr, Nb, Mo, Hf, Ta, W, and Lu), are given. The exceptional qualities of the 2D non-Ti MXene outperform standard Ti-MXene in several applications. There is many advancement in top-down as well as bottom-up production of MXenes family members, which allows for exact control of the M-characteristics MXene NMs to contain cutting-edge applications. This study offers a systematic evaluation of existing research, covering everything in producing complex M-MXenes from primary limitations to the characterization and selection of their applications in accordance with their novel features. The development of double metal combinations, extension of additional metal candidates beyond group-(III-VI)B family, and subsequent development of the 2D TM carbide/TMs nitride/TM carbonitrides to 2D metal boride family are also included in this overview. The possibilities and further recommendations for the way of non-Ti MXene NMs are in the synthesis of NMs will discuss in detail in this critical evaluation.

Size prediction of drug-loaded Polymeric (PLGA) microparticles prepared by microfluidics

Drug-loaded poly (lactic-co-glycolic acid) (PLGA) microparticles with ex-act control over size and homogeneity were created using a glass microfluidic cross-junction droplet generator. A numerical simulation based on the volume-of-fluid (VOF) method is used to study the behavior of two immiscible fluids that are injected into the microdevice: hydrophobic drug and (PLGA) in dichloromethane (DCM) serving as the dispersed phase and aqueous solution of poly (vinyl alcohol) (PVA) as the continuous phase. The simulation predicts the created emulsion droplet size regulation by adjusting the phase's flow rate. In a procedure known as droplet shrinking, dichloromethane extraction, and evaporation took place to further transform the monodisperse emulsion into PLGA microparticles. A numerical relationship is also given for the variations in the volume of droplets during shrinkage. The numerical results were consistent with the experiments. To further illustrate this technique's ability to manufacture designed microspheres with the least amount of repeated experiments, as well as the importance of the droplet microfluidic approach in terms of regulating diameter and monodispersity, opioid antagonist naltrexone is loaded in PLGA microspheres. According to the findings, integrating a versatile microfluidic approach with numerical methodologies enables the development of more reliable and reproducible drug delivery systems.

Exact global control of small divisors in rational normal form *

Rational normal form is a powerful tool to deal with Hamiltonian partial differential equations without external parameters. In this paper, we build rational normal form with exact global control of small divisors. As an application to nonlinear Schrödinger equations in Gevrey spaces, we prove sub-exponentially long time stability results for generic small initial data.

A Mobile App Driven Smart Ball Launch System for Solo Sports Training

Abstract: In today's world, athletes face intense competition in a variety of sports, but there are few opportunities for them to practice or evaluate their performance on their own, making it difficult for them to grow. Thus, a system is proposed in this paper that allows players to conveniently practice alone without requiring human assistance and may also help them in analyzing their skills. The method mostly concentrates on tennis game. The automatic ball launches for practice is the main aim of the system. With the assistance of a Node MCU that can interact over the internet, the system gives the user exact control over when to launch balls, what kind of ball to launch, and how to launch them remotely. Which is possible on mobile devices due to Blynk app interface. Typically, the system offers three different ball launch types: over spin, backspin, and rapid ball launch. It also allows for exact speed control of the motors used to make the ball launch.

Exact Controllability for Mean-Field Type Linear Game-Based Control Systems

Exact Controllability for Mean-Field Type Linear Game-Based Control Systems

Exact controllability for systems describing plate vibrations. A perturbation approach

Exact controllability for systems describing plate vibrations. A perturbation approach

Optimal quadratic full state feedback control of nonlinear affine systems

The solution of the optimal quadratic full-state feedback closed-loop control of a nonlinear affine system problem is presented and solved. This solution uses the State-Dependent Coefficient (SDC) form of a nonlinear system and the Calculus of Variations. Further, it is shown that this solution enables the computation of the value function associated with the respective Hamilton-Jacobi-Bellman equation thus satisfying the necessary and sufficient conditions for optimality. The use of the SDC form representation in the optimal solution for a nonlinear affine system results in an explicit and exact full-state feedback closed-loop control implementation as opposed to the existing open-loop solutions of the optimal control. This solution, like for the linear case, is non-causal and thus cannot be solved in real-time. The closed-loop application involves precomputing a time-varying full-state feedback matrix. The optimal feedback is a linear combination of the current state. The time-varying gain matrix is the backward solution of a non-symmetric matrix Riccati equation. Conditions for the stability of the full-state feedback are presented. This new representation of the optimal solution gives a well-understandable algorithm that enables implementation in the closed loop of the optimal feedback control of a non-linear system which is not possible with the existing optimal open loop representations.

Time-Optimal Motions of a Mechanical System with Viscous Friction

Optimal control is a critical tool for mechanical robotic systems, facilitating the precise manipulation of dynamic processes. These processes are described through differential equations governed by a control function, addressing a time-optimal problem with bilinear characteristics. Our study utilizes the classical approach complemented by Pontryagin’s Maximum Principle (PMP) to explore this inverse optimal problem. The objective is to develop an exact piecewise control function that effectively manages trajectory control while considering the effects of viscous friction. Our simulations demonstrate that the proposed control law markedly diminishes oscillations induced by boundary conditions. This research not only aims to delineate the reachability set but also strives to determine the minimal time required for the process. The findings include an exact analytical solution for the stated control problem.

Time-harmonic electromagnetics with exact controllability and discrete exterior calculus

Time-harmonic electromagnetics with exact controllability and discrete exterior calculus

Numerical method of the exact control for the elastic string problem with moving boundary

The objective of this article is to investigate, analytically and numerically, the exact control problem associated with a mathematical model that describes the vertical vibrations of elastic strings, with moving contours. To determine the approximate numerical solution, following the description of the HUM (Hilbert Uniqueness Method), the finite element method associated with the Newmark method was used for the adjunct problem and the backward problem. To calculate the optimal control, the conjugated gradient method is used. The properties of a numerical problem must be consistent with the theoretical mathematical one. However, in order to obtain the numerical control, the grid is of fundamental importance, so we used the Bi-Grid technique. In this way, we developed an algorithm to solve this problem. Numerical simulations were performed for different initial data and moving contours, with and without the Bi-Grid algorithm and the numerical results confirmed the consistency between the theoretical and numerical results.

Shape, velocity, and exact controllability for the wave equation on a graph with cycle

Exact controllability is proved on a graph with cycle. The controls can be a mix of controls applied at the boundary and interior vertices. The method of proof first applies a dynamical argument to prove shape controllability and velocity controllability, thereby solving their associated moment problems. This enables one to solve the moment problem associated with exact controllability. In the case of a single control, either boundary or interior, it is shown that exact controllability fails.

On the minimum driver node set of k-uniform linear hypertree networks

The exact controllability research framework of complex networks points out that the controllability of the network has a great relationship with the minimum number of driver nodes. It is generally believed that the smaller the minimum number of driver nodes and the lower the cost of external control of the whole network to achieve the ideal state, the better the controllability of networks. In this paper, the minimum driver node problem of a hypernetwork is transformed into the maximum multiplicative problem of the eigenvalue of its 2-section graph. The minimum driver node numbers of two types of typical k-uniform hypertree networks are described, and their bounds are also given. By designing an algorithm, the method of characterizing the driver node set is obtained, and it is found that the selection of the minimum driver nodes of the network tends to the nodes with low hyperdegree. In addition, the paper verifies the minimum driver node set and the theoretical analysis results of controllability by simulation analysis.