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Academic laboratories, Final disposition, Hazardous waste, Waste management, Waste treatment, Electrical and Electronic Engineering, Waste recovery, Disposition, Unit of analysis, Academic community, Business, Treatment management, and Encapsulation (computer programming)

Laboratory higher education institutions can generate a wide range of wastes, many of which have hazardous characteristics. The uncontrolled accumulation of such wastes also has a significant impact on the environment, safety and health of the academic community. This work formulates strategies that allow the development of integrated solutions to mitigate the latent risk for the community at Institución Universitaria Colegio Mayor de Antioquia, Colombia, and its surroundings. Therefore, it is considered to quantify the generation of waste in the units of analysis of different experimental spaces and evaluate the factors involved in the implementation of strategies for diagnosis, waste recovery, treatment, and final disposition. Based on the diagnosis and characterization of wastes, alternatives are evaluated that help to prevent and, in other cases, mitigate the impacts that they can cause, in order to consolidate a protocol for waste management. Hazardous waste disposition strategies, treatment mechanisms and minimization strategies, such as microchemistry, precipitation recycling, encapsulation and immobilization methods, evaporation as well as solvent recovery, have been implemented.

Boost converter, Flip bifurcation, Neimar-Sacker bifurcation, Nonlinearity, ZAD control technique, Electrical and Electronic Engineering, Physics, Jacobian matrix and determinant, symbols.namesake, symbols, Pulse-width modulation, Condenser (heat transfer), Control theory, Nonlinear system, Eigenvalues and eigenvectors, Periodic graph (geometry), and Lyapunov exponent

In this paper, an analytical and numerical study is conducted on the dynamics of the current in the condenser of a boost converter controlled with ZAD, using a pulse PWM to the symmetric center. A stability analysis of periodic 1T-orbits was made by the analytical calculation of the eigenvalues of the Jacobian matrix of the dynamic system, where the presence of flip and Neimar–Sacker-type bifurcations was determined. The presence of chaos, which is controlled by ZAD and FPIC techniques, is shown from the analysis of Lyapunov exponents.

Nitrogen removal, Series CSTR, VFCW modelling, Wetland modelling, Electrical and Electronic Engineering, General Computer Science, Ammonia, chemistry.chemical_compound, chemistry, Continuous stirred-tank reactor, Nitrification, Constructed wetland, Nitrogen, chemistry.chemical_element, Reaction rate, Environmental engineering, Denitrification, Wastewater, and Environmental science

This work shows simulation results for subsurface vertical flow constructed wetland (VFCW) using a series CSTR model. The VFCW considered received the outflow from a domestic wastewater treatment plant. In addition, it was planted with Cyperus sp. and filter media was unsaturated. The model was based on an unsteady state mass balance for ammonia, nitrites, and nitrates, using one to three series CSTRs. Nitrogen transformation mechanisms considered were ammonification, nitrification, plant uptake and denitrification. The following effects were evaluated: the number of reacting CSTRs from one to three; the occurrence of the reaction in second and third CSTRs for the case that three CSTRs hold; the use of either equal or different values of reaction rate parameters between CSTRs; and the discretization of the reaction rate parameters. The inflow and outflow measurements of ammonium, nitrites, and nitrates were used for model calibration. The estimated parameters included the reaction rate coefficients and reactor water volume. The coefficient of determination (R2) evidenced a satisfactory capability of simulating outlet pollutant concentrations. Two and three reacting CSTRs achieved similar R2 value (0.54-0.55), whereas one reacting CSTR achieved an R2 of 0.39, and three CSTRs with reaction only in the first tank achieved an R2 of 0.42. Discretization of the nitrification rate for the case of two reacting CSTRs led to an R2 of 0.94. The parameter sensitivity analysis revealed a significant effect of model parameters on the R2 value.

Parameters estimation, Linear induction motor, DSP-based electric-drives, Per-phase equivalent circuit, Electrical and Electronic Engineering, General Computer Science, Synchronous motor, Three-phase, Air gap (plumbing), Leakage inductance, Physics, Induction motor, Control theory, Power factor, and DC motor

This work describes a method to characterize a three-phase linear induction motor in order to determine the various parameters used in its per-phase equivalent circuit by a DSP-based electric-drives system. In LIM (Linear Induction Motor), the air gap is very large compared with the RIMs (Rotary Induction Motors). Further, the secondary part normally does not have slotted structure. It is just made of aluminum and steel plates. Therefore, the effective air gap is larger than the physical air gap. High air gap makes a larger leakage inductance. It leads to lower efficiency and lower power factor. DC resistance test will be done to determine the value of Rs. The primary Inductance Ls will be calculated by running the LIM at synchronous speed. The secondary parameters i.e. Llr and Rr′ will be calculated by blocked-mover test. The experiment for no load test is shown and include a DC motor coupled to the LIM under test. Two methods to calculate the secondary parameters are described.

Droop control, Frequency, Microgrid, Transient response, Virtual inertia, Electrical and Electronic Engineering, General Computer Science, Voltage droop, Computer science, Control theory, Inertia, media_common.quotation_subject, media_common, Inverter, and Optimization algorithm

The inertia issues in a microgrid can be improved by modifying the inverter control strategies to represent a virtual inertia simulation. This method employs the droop control strategy commonly used to share the power of a load among different power sources in the microgrid. This paper utilizes a modified droop control that represents this virtual inertia and applies an optimization algorithm to determine the optimal parameters and improve transient response. The results show better control when different variations are presented in the loads, leading the microgrid to have a better control of the operation. The optimization method applied in this research allows improvement to the transient response, thus avoiding unnecessary blackouts in the microgrid.

Buck converter, DC-AC inverter, Feedback control, Signal generator, Zero hysteresis, Electrical and Electronic Engineering, General Computer Science, Electronics, Computer science, Voltage, Inverter, Power inverter, AC power, Analogue electronics, Electrical engineering, business.industry, and business

This paper presents the design and experimental validation of a DC-AC power inverter, controlled analogically with zero hysteresis. A control circuit was built using analog electronics components, and optocoupler devices are used to couple the control module with the power stage. The design of DC-AC inverter with electronics circuit and implementation are shown in detail. Experimental results show the effectiveness of control technique and implementation, leading to a robust system concerning load disturbances. The developed inverter offers the possibility of generating regulated output voltages of different signal types, both DC and AC, variable in frequency and in amplitude, useful for feeding a load with various AC signals.

Waveform, Control theory, Converters, Computer science, Inverter, Alternating current, law.invention, law, MATLAB, computer.programming_language, computer, Voltage, and Buck converter

Introduction: Power converters are used in microgrids to transfer power to the load with a regulated voltage. However, the DC-AC converters present distortions in the waveform that can be improved with the help of real-time controllers.Objective: Evaluate the response in alternating current of the buck converter controlled using ZAD-FPIC technique.Methodology: Based on the differential equations that describe the buck power converter, the ZAD and FPIC controllers are designed, simulations of the complete controlled system are made in Simulink of MATLAB, the system is implemented experimentally, and the controller is executed in real-time with the help of a DS1104 from dSPACE. In the end, several tests are carried out to check the effectiveness of the controller.Results: The results show that the controller allows good stability against different variations in the system and in the load.Conclusions: The ZAD-FPIC technique controls the variable and tracks changes in the waveform, magnitude, and frequency of the reference signal. The controller presents good stability to different tests, tracking the reference signal after each event.

chlorophyll, fluorescein, fluorescence, green leaf extract, light-emitting diode, Electrical and Electronic Engineering, Green leaf, Diode, Optoelectronics, business.industry, business, Excitation, Spectroscopy, Fluorescein, chemistry.chemical_compound, chemistry, Light-emitting diode, law.invention, law, Infrared, Fluorescence, Materials science, and food and beverages

This paper presents the characterization of excitation source LEDs and sensors without filters for measuring fluorescence in fluorescein and green leaf extract. For this purpose, eight light-emitting diodes (LEDs) were used with the following characteristics: one blue, one green, one red, one infrared, and four violets. The first four LEDs were used as sensors without filters to detect fluorescence induced by the other four violet LEDs in 11 samples of different fluorescein concentrations and in 14 samples of different dilutions of green leaf extract. The results show that infrared LEDs can detect the red emission of green leaf extract and red and infrared LEDs detect the fluorescence of fluorescein in concentrations of up to 1.8 μM. The developed system allows and facilitates teaching optical spectroscopy in basic education without incurring high costs.

Control and Systems Engineering, Nonlinear system, Control theory, Computer science, Micro grid, Control variable, Experimental validation, Washout filter, Sliding mode control, Converters, and Voltage reference

This paper presents an experimental validation of a non-linear sliding-mode control based on a washout filter when is submitted to alterations in the load, control parameter, and voltage reference. The numerical and the experimental tests are compared to visualize the non-linear effects caused by the power electronic converters and a comparison of the errors obtained for both test is presented. The results show that similar behaviors are presented in both cases with low error in the controlled variable vc. Furthermore, when representing bifurcations, both tests show similar behaviors, although the experimental test has a low displacement in the signal. This method is useful to monitor non-linear effects of micro grid and to design new filters or modify settings in the parameters.

electricity markets, economic dispatch, optimization, maximum capacity, online operation, power system, unit commitment, lcsh:Technology, lcsh:T, Energy (miscellaneous), Energy Engineering and Power Technology, Renewable Energy, Sustainability and the Environment, Electrical and Electronic Engineering, Control and Optimization, Engineering (miscellaneous), Maximum power transfer theorem, Computer science, Economic dispatch, Cost optimization, Electric power system, Electricity generation, Expression (mathematics), Reliability engineering, Electricity market, and Power system simulation

This paper presents an online economic re-dispatch scheme based on the generation cost optimization with security constraints to mitigate line overloads before and after line and generation contingencies. The proposed optimization model considers simplification of mathematical expressions calculated from online variables as the power transfer distribution factor (PTDF) and line outage distribution factor (LODF). Thus, a first algorithm that calculates economic re-dispatch for online operation to avoid overloads during the normal operation and a second algorithm that calculates online emergency economic re-dispatch when overloads occur due to line and generator contingencies are proposed in this paper. The results show that the proposed algorithms avoid overload before and after contingencies, improving power system security, and at the same time reducing operational costs. This scheme allows a reduction of power generation units in the electricity market during online operation that considers line overloads in the power system.

Control and Systems Engineering, Voltage reference, Switching frequency, Voltage source, Installation, Control theory, Robustness (computer science), Software, business.industry, business, Inverter, Computer science, and Transient state

This article presents the behavior of an inverter in both DC-DC and DC-AC configurations controlled with a quasi-sliding control technique known as ZAD-FPIC. An analysis of transient behavior, disturbances in the load, changes in the reference signal, and disturbances in the power supply are presented, and control techniques have been designed to manage an inverter in real-time. The software has been designed to execute the controllers by using Simulink-MATLAB libraries and the ones provided when installing the DS1104 board. The digitally implemented ZAD-FPIC controllers use a DS1104 in order to control the converter and thus meet the requirements of fixed switching frequency, robustness, and good performance in DC signal regulation tasks. The controllers work well during the transient state because they dampen overshoots and reduce settling times. The results show that the system regulates well before changes of the reference and rejects disturbances in the load and the source voltage. Additionally, it has been observed that the regulation error varies depending on the reference voltage level.

Control and Systems Engineering, Computer science, Control theory, Digital signal processor, Direct current, Duty cycle, Electrical network, law.invention, law, Alternating current, Ripple, and Buck converter

This paper presents the theoretical and the experimental results of a direct current and alternating current buck converter configured as an inverter controlled by zero average dynamics and fixed point induced control techniques. The system is modeled and implemented in an electrical circuit in order to apply the control techniques and the tracking voltage at the output of the alternating current signals. The tests are based on comparing simulation and experimental results in order to identify the robustness of the circuit when subjected to disturbances. The results show that zero average dynamics and fixed point induced control techniques implemented digitally in a digital signal processor meet the requirements of fixed switching frequency, robustness, and good performance in alternating current signal tracking tasks, which are the benefits of this controller. The fixed switching frequency is evidenced in the results related to the non-saturated duty cycle achieving a very good commutation and reducing electromagnetic interferences. For high frequencies, the value of the inductive-capacitive filter should be decreased when tracking alternating current signals; however, this increases ripple in the signal and tracking errors.