High levels of heavy metals in industrial wastewater pose a significant environmental concern due to their toxicity to living organisms and ecosystems. Traditional techniques that use chemical ...coagulants to eliminate heavy metals from industrial wastewater have proven effective. However, the use of chemical coagulants produces sludge that is highly toxic and requires careful management. On the other hand, natural coagulants offer a cost-effective and sustainable alternative that is safer to handle, locally available, and potentially useful for resource recovery. These benefits make natural coagulants a promising substitute for chemical coagulants. This study aimed to investigate the performance of combining Date stone powder (DSP) and aluminum chloride (AlCl3), to remove heavy metals from industrial wastewater efficiently. Through an optimization process of DSP/AlCl3 dosage and pH, the study sought to determine the optimal conditions for heavy metal removal. The main findings indicate that a DSP/AlCl3 dosage of 7:1 (g/g) was the most effective coagulant dosage, resulting in high removal efficiencies for COD (88.56%), color (89.56%), TSS (99.00%), NH3-N (92.50%), Mn (94.10%), Fe (95.47%), Zn (93.57%), Al (88.42%), and Ni (93.3%) at pH 8. Interestingly, the results of pH optimization showed that no pH modification was necessary, as it already achieved high removal efficiencies for COD (84.57%), color (88.94%), TSS (99.00%), NH3-N (92.25%), Mn (92.66%), Fe (90.57%), Zn (95.59%), Al (99.00%), and Ni (93.33%). This study demonstrates that the hybrid DSP/AlCl3 coagulation method can be an effective and sustainable solution for removing heavy metals from industrial wastewater. However, further research is necessary to assess its scalability and potential limitations.
In this paper, a novel multilevel dc-ac inverter is proposed. The proposed multilevel inverter generates seven-level ac output voltage with the appropriate gate signals' design. Also, the low-pass ...filter is used to reduce the total harmonic distortion of the sinusoidal output voltage. The switching losses and the voltage stress of power devices can be reduced in the proposed multilevel inverter. The operating principles of the proposed inverter and the voltage balancing method of input capacitors are discussed. Finally, a laboratory prototype multilevel inverter with 400-V input voltage and output 220 V rms /2 is implemented. The multilevel inverter is controlled with sinusoidal pulse-width modulation (SPWM) by TMS320LF2407 digital signal processor (DSP). Experimental results show that the maximum efficiency is 96.9% and the full load efficiency is 94.6%.
Digital signal processing (DSP) cores (kernels) are key components of modern consumer electronics devices. However, protection of DSP kernels is very crucial considering its vulnerability to hardware ...threats such as reverse engineering (RE). Functional obfuscation is one of the security mechanisms which provide protection against RE. However, functional obfuscation logic is in itself vulnerable to removal attack. This Letter presents a novel anti-removal logic (ARL) unit which ensures protection against the removal attack on functional obfuscation logic. Further, the ARL unit is itself safeguarded against removal attack by incorporating design architecture customisation and camouflaging. Designer can customise and camouflage the internal gate structure network of the ARL blocks post-synthesis (post-mapping and fitting). The proposed ARL unit integrated with functionally obfuscated DSP design, yielded lightweight and highly secured solution against removal attack when compared to an existing approach. The proposed approach reported on an average 42.57% reduction in gate count and on an average 66.67% enhancement in security compared to a recent existing approach.
Probabilistically shaped (PS) quadrature amplitude modulation (QAM) recently established itself as the solution to adopt for state-of-the-art coherent transponders. This in turn has drawn attention ...to the rework of conventional digital signal processing (DSP) algorithms, which are not optimal for QAM-PS. In this context, we propose a novel pilot-aided equalization technique based on the ubiquitous radius directed equalizer (RDE). Our solution employs both payload and time-multiplexed pilot symbols for the adaptive filters update. The payload symbols are treated on the basis of the likelihood of their correct blind assignment. We show that this approach is at the same time able to reduce the global pilot overhead (POH) required by the DSP chain and to provide greatly improved performance in the tracking ability of the equalizer in the event of fast state of polarization rotations. We describe a simulation environment in which we model accurately static and dynamic polarization-related impairments. We test our algorithm over different shaped modulation formats and in the presence of transceiver impairments and demonstrate its superior performance with respect to standard feed-forward implementations in all the scenarios considered.
•An artificial bee colony based MPPT under partially shaded conditions is proposed.•Photovoltaic systems are considered.•A co-simulation methodology combining Simulink and Pspice has been ...adopted.•Excellent efficiency and tracking performance compared to the PSO-based MPPT.•The effectiveness of the proposed method has been confirmed experimentally.
Artificial bee colony (ABC) algorithm has several characteristics that make it more attractive than other bio-inspired methods. Particularly, it is simple, it uses fewer control parameters and its convergence is independent of the initial conditions. In this paper, a novel artificial bee colony based maximum power point tracking algorithm (MPPT) is proposed. The developed algorithm, does not allow only overcoming the common drawback of the conventional MPPT methods, but it gives a simple and a robust MPPT scheme. A co-simulation methodology, combining Matlab/Simulink™ and Cadence/Pspice™, is used to verify the effectiveness of the proposed method and compare its performance, under dynamic weather conditions, with that of the Particle Swarm Optimization (PSO) based MPPT algorithm. Moreover, a laboratory setup has been realized and used to experimentally validate the proposed ABC-based MPPT algorithm. Simulation and experimental results have shown the satisfactory performance of the proposed approach.
This study aims to present the discrete models and the methodology to implement real-time simulations of electric machines using a low-cost digital signal processor (DSP). The DC machine and the ...three-phase induction machine are modelled in real-time using a Texas Instruments DSP TMS28379D, where the discrete models are implemented using C language. A minimum time-step of 1 µs can be achieved for the DC machine and 1.5 µs for the inductions machine in the experimental hardware. To validate the described models and show their precision, they are compared with commercial computational models from PSIM®. In addition, closed-loop speed control strategies are applied to the real-time DSP experimental models, showing perfect concordance with the machine theory. For the DC machine, a speed control strategy with an inner current control loop is applied and for the induction machine, a field-oriented control for the speed control. The proposed real-time simulation hardware has a great potential for low-budget research and educational purposes since it can replace a real machine setup for a very low price, with great accuracy, variable parameters and free from risks, such as accidents or equipment damage. Furthermore, it uses cheap hardware with free software and a high-level programing language.
This article establishes the novel D+∗, a risk-aware and platform-agnostic heterogeneous global path planner for robotic navigation in complex environments. The proposed planner addresses a ...fundamental bottleneck of occupancy-based path planners related to their dependency on accurate and dense maps. More specifically, their performance is highly affected by poorly reconstructed or sparse areas (e.g. holes in the walls or ceilings) leading to faulty generated paths outside the physical boundaries of the 3-dimensional space. As it will be presented, D+∗ addresses this challenge with three novel contributions, integrated into one solution, namely: (a) the proximity risk, (b) the modeling of the unknown space, and (c) the map updates. By adding a risk layer to spaces that are closer to the occupied ones, some holes are filled, and thus the problematic short-cutting through them to the final goal is prevented. The novel established D+∗ also provides safety marginals to the walls and other obstacles, a property that results in paths that do not cut the corners that could potentially disrupt the platform operation. D+∗ has also the capability to model the unknown space as risk-free areas that should keep the paths inside, e.g in a tunnel environment, and thus heavily reducing the risk of larger shortcuts through openings in the walls. D+∗ is also introducing a dynamic map handling capability that continuously updates with the latest information acquired during the map building process, allowing the planner to use constant map growth and resolve cases of planning over outdated sparser map reconstructions. The proposed path planner is also capable to plan 2D and 3D paths by only changing the input map to a 2D or 3D map and it is independent of the dynamics of the robotic platform. The efficiency of the proposed scheme is experimentally evaluated in multiple real-life experiments where D+∗ is producing successfully proper planned paths, either in 2D in the use case of the Boston dynamics Spot robot or 3D paths in the case of an unmanned areal vehicle in varying and challenging scenarios.
•D+∗ occupancy-based risk-aware, platform-agnostic, heterogeneous global path planner.•Risk areas in proximity to occupied spaces.•Explicitly unknown areas as a risk.•Dynamic 3D map updates and expansions for planning.•D+∗ has been tested and evaluated on a quadruped Spot robot and an UAV in the field.
Directly-modulated laser (DML) is widely employed in intensity modulation and direct detection (IMDD) system due to its low cost and high output power. However, the corresponding frequency chirp is ...regarded as one of the main disadvantages for its application in passive optical networks (PONs). In this paper, we theoretically analyze the frequency response evolution of DML based system under different chirp and dispersion conditions, proving that the system bandwidth can be improved by interactions between negative dispersion and DML chirp. Based on this concept, we experimentally demonstrated downstream 50 Gb/s PAM4 signal transmission over 20 km single-mode fiber (SMF) access based on the 10 Gb/s DML operating at 1310 nm and avalanche photodiode (APD). A dispersion-shifted fiber (DSF) providing -150 ps/nm dispersion at 1310 nm in the optical line terminal (OLT) is used to pre-equalize the frequency response of bandwidth-limited directly modulated signals in the optical domain. Thanks to our proposed dispersion-supported equalization (DSE) technique, the system bandwidth can be improved by 5 GHz. Feed-forward equalization (FFE), decision feedback equalization (DFE) and Volterra filter are employed to evaluate the signal performance improvement, respectively. By evaluating the receiver sensitivity, the DSE combined with FFE scheme shows 2 dB improvement than the complex Volterra algorithm, indicating its potential to reduce the complexity of digital signal processing (DSP) and therefore a lower cost and power consumption in PON.
As 100-Gb/s coherent systems based on polarization- division multiplexed quadrature phase shift keying (PDM-QPSK), with aggregate wavelength-division multiplexed (WDM) capacities close to 10 Tb/s, ...are getting widely deployed, the use of high-spectral-efficiency quadrature amplitude modulation (QAM) to increase both per-channel interface rates and aggregate WDM capacities is the next evolutionary step. In this paper we review high-spectral-efficiency optical modulation formats for use in digital coherent systems. We look at fundamental as well as at technological scaling trends and highlight important trade-offs pertaining to the design and performance of coherent higher-order QAM transponders.
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