We present an optimized design for GaAs/AlGaAs quantum Cascade lasers operating at 4.1THz. This was based on a three-well active module with diagonal radiative transition. This was performed by modifying the existing model structure, to reduce the parasitic anticrossings (leakage currents) as well as the optical gain linewidth. While the gain FWHM was reduced by more than 50% the gain peak was increased by about 23.3%.

The study of intelligent design methods is becoming a hot topic for the design of turbine Cascades. This paper proposes a data-based policy model to achieve intelligent design. To gain a high-quality policy model, empirical equations and "space extending + elitism" are adopted to dynamically optimize database. This guarantees the quality of the model. Compared to traditional optimization design approaches, the proposed method relies on less human experience to design a turbine Cascade. Ten different turbine Cascades are used to verify this method. Results show that, aerodynamic performance of the Cascades redesigned is either the same as or better than that of the traditional Cascades. The computing time is reduced by more than one order of magnitude compared to a "CFD + optimization algorithm" or "surrogate model + optimization algorithm" method. With the advantages in computing time and intelligence, the proposed novel method shows the possibility of replacing traditional design methods.

This paper employs the Particle Swarm Optimization (PSO) method to solve the problem of the optimal design of Cascade stilling basins. PSO is a relatively recent heuristic search method whose mechanism is inspired by the swarming or collaborative behavior of biological populations. The objective of this research is to minimize the total construction cost of Cascade stilling basins, which is a function of height of the falls and length of stilling basins, while fulfilling the hydraulic and topographical criteria. To illustrate the application of PSO, a benchmark design is taken from the work of Vittal and Porey [1] on a Cascade stilling basin for the Tehri Dam, India.

BACKGROUND: Familial hypercholesterolemia (FH) is one of the most common genetic disorders, which leads to premature coronary artery disease (CAD). It has been suggested that heterozygous FH affects around 1: 250 to 1: 500 in the general population or even more than this, and homozygous FH affects 1: 1000000 of the population. If patients with FH are not diagnosed and treated early in life, many of them will develop premature CAD event. As most of the patients with FH are undiagnosed, it is recommended that the general population be screened for high risks of the events since early treatments can reduce the risk of premature CADs. The clinical diagnostic criteria for FH consist of increased plasma low-density lipoprotein cholesterol (LDL-C), clinical features and family history of CAD. However, deoxyribonucleic acid (DNA)-based detection of FH mutation has high diagnostic values. As there was no screening for FH in Iran up until now, we have started screening and registering patients with FH using the Cascade method. METHODS: We detected FH subjects in the general population by screening laboratories according to their high LDL-C levels (more than 190 mg/dl or 150 mg/dl if receiving treatments), while our second approach was hospital-based in which one screens hospitalized patients with premature CAD events. RESULTS: We intended to screen families of indexed patients to provide standard care and therapy in order to optimize their LDL-C. CONCLUSION: This article provides detailed information on the rationale and design of this screening and registry in Iran.

Due to increasing application of multi effect falling film evaporators in food industry. the exact modeling of these processes is important. The aim of this paper is use ability of nonlinear modeling in determining falling film evaporator state variables. Because of large time delays and process disturbances, the tight exact control of product concentration is difficult. By using the nonlinear modeling, the control of three effect falling film evaporator with the use of Cascade control algorithm is analyzed This paper discusses the application and design of a Cascade algorithm to control the product concentration in a milk powder three effect falling-film evaporator. It has been shown that the disturbance rejection properties can be significantly improved with Cascade control while still maintaining the tracking properties.

In this paper, the problem of controlling PWM single-phase AC/DC converters is addressed. The control objectives are twofold: (i) regulating the output voltage to a selected reference value, and (ii) ensuring a unitary power factor by forcing the grid current to be in phase with the grid voltage. To achieve these objectives, the singular perturbation technique is used to prove that the power factor correction can be done in the open-loop system with respect to certain conditions that are not likely to take place in reality. It is also applied to fulfill the control objectives in the closed-loop through a Cascade nonlinear controller based on the three-time scale singular perturbation theory. Additionally, this study develops a rigorous and complete formal stability analysis, based on multi-time-scale singular perturbation and averaging theory, to examine the performance of the proposed controller. The theoretical results have been validated by numerical simulation in MATLAB/Simulink/SimPowerSystems environment.

The ball and beam system is one of the most popular laboratory setups for control education. In this paper, we design a fuzzy PD Cascade controller for a ball and beam system using Asexual Reproduction Optimization (ARO) technique. The ball & beam system consists of a servo motor, a grooved beam, and a rolling ball. This system utilizes a servo motor to control ball’s position on the beam. Changing the angle of servo motor results in the movement of the beam and, subsequently, the ball rolling on it. We designed a fuzzy PD Cascade and a PD Cascade controller scheme which consists of the two controller loops. The first (outer) controller and the second (inner) controller are organized in a Cascaded construction.

In this paper, the problems of control and stabilization of switched nonlinear Cascade systems is investigated. The so called simultaneous domination limitation (SDL) is introduced in previous works to assure the existence of a common quadratic Lyapunov function (CQLF) for switched nonlinear Cascade systems. According to this idea, if all subsystems of a switched system satisfy the SDL, a CQLF can be constructed by employing the back-stepping approach. The major shortcoming of the SDL is that this limitation cannot be satisfied for complicated switched nonlinear systems. Therefore, a CQLF cannot be constructed by employing the back-stepping approach. Moreover, if SDL is satisfied, only stabilization problem can be solved. In this paper, a new approach based on state conversion is introduced to solve the stabilization and control problems of switched nonlinear Cascade systems without any limitation. Several simulation and experimental studies are provided to show the effectiveness of the proposed approach.