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Automation of moisture level measurement in charcoal briquettes
No full textCharcoal briquettes, made from organic waste. Their quality depends significantly on moisture content, which affects electrical conductivity. This study focuses on automating moisture measurement using electrical resistance. The device employs a current-sensing circuit, an analog-to-digital converter, Hall effect sensors, and servo-driven clamps with plate-shaped electrodes to grip briquettes and measure resistance. Briquettes are fed into the system by a rotary feeder. Testing on batches of 10 briquettes classified as dry, half-dry, and wet showed classification success rates of 100% for either dry or wet conditions and 55.6% for half-dry conditions, despite occasional errors from resistance values outside predefined ranges. Resistance ranges recorded were 11.38–15.80 MΩ (dry), 3.37–7.59 MΩ (half-dry), and 0.02–0.80 MΩ (wet), corresponding to moisture contents of 0–3.03%, 7.27–11.52%, and 11.52–16.36%, respectively. The half-dry resistance values were closer to the wet range, indicating the half-dry batches were not distinctly intermediate between dry and wet. The rotary feeder showed practical reliability with 88% success for loading briquettes into chambers and 77.5% for positioning them on the measurement table, enabling effective automation. Overall, the system demonstrated the capability to measure moisture content and classify briquettes by dryness
Development of a Nonlinear Mathematical Model and Gain Scheduling-Based Control for Wind Turbine Test Rig
No full textUniversitas Prasetiya Mulya is developing a modular wind turbine test rig equipped with a data acquisition system and wind speed controller. However, the control system still needs to be developed. This research aims to design a control system that maintains turbine output power stability by regulating generator torque and pitch angle using a gain scheduling approach. The developed dynamic model includes aerodynamic, drivetrain, generator, and pitch actuator subsystems, based on experimental and simulation data. The tower and drivetrain are treated as rigid due to high structural integrity. The wind speed range used in modeling is 1–15 m/s, with a rated speed of 6 m/s. Below rated speeds, torque control maximizes power extraction, while above rated speeds, pitch control regulates rotor dynamics. The nonlinear model is linearized at above-rated conditions to obtain PID parameters for accurate pitch reference tracking. Simulation results show that the torque controller maintains a maximum power coefficient (Cp) of 0.3476 and an optimal tip speed ratio (TSR) of 3.931, while the pitch controller tracks references with 1–8.4% error depending on wind speed
Detecting Anomalous Ship Movements in Indonesian Seas Using Convolutional Neural Networks
No full textDetecting unusual ship movements is a crucial feature of maritime surveillance, particularly in Indonesian waters, where illegal fishing, unauthorized resource exploitation, drifting ships, and unauthorized navigation pose significant threats to safety and security. This research proposes a Convolutional Neural Network (CNN)-based methodology for categorizing ship movement behaviors into two classifications: drifting and non-drifting. The dataset has 79,200 image-based samples, uniformly divided between the two categories. The proposed model is trained and tested using accuracy, recall, precision, F-score performance metrics. The experiment shows that the resulting model successfully classifies the movement of the ship well. This is evidenced by a testing accuracy of 0.98, a precision of 99%, a recall of 95%, an F-score of 97%, indicating that the CNN was highly accurate and robust, suggesting it could be utilized in real-time maritime anomaly detection systems
Single shot sub-micron lensless digital holographic microscopy
No full textHigh-resolution lensless microscopy offers a compact and cost-effective alternative to traditional optical microscopy, with various applications such as biomedical imaging and wafer-level testing. This paper introduces a model-based understanding of how to exploit the physical properties of the wave field despite the limited sampling capabilities of digital cameras, providing insights into the true resolution potential of lensless holographic imaging systems. Through the inversion of the propagation operator between two differently scaled sampling grids in the camera and object planes, we present a diffraction-limited imaging approach using a single digital hologram. We validate the method through both single-shot as well as temporally phase-shifted measurements and demonstrate lensless sub-micron imaging in both reflection and transmission mode
L’amplification par fibre optique dopée à l’erbium : la clé du monde de l’internet
No full textL’amplificateur à fibre dopée à l’erbium a non seulement révolutionné les télécommunications mais également rendu possible l’Internet dans son caractère d’ubiquité ou présence globale. L’explication vient de ce que désormais, les données numériques sont transportées à l’autre bout du monde sous forme de signaux optiques, sans traitement électronique sur leur parcours pour limiter le débit, et sans perte de puissance non plus, grâce à cette amplification optique
Investigation of heavy metals in indoor dusts of households in an indubitable range from a landfill located in south-western India
No full textWaste treatment plants, landfills, and dump yards are surplus in trash that emits various elements, including heavy metals, into the atmosphere either by human activities or by any fire events. This study investigates the heavy metals in indoor dusts of households situated at various directions and varying distances away from the landfill and its impact on human health and the environment. The concentration of heavy metals in dust samples followed the order (mg/kg): Fe (14905.68) > Mn (377.57) > Cu (275) > Zn (219.41) > Cr (145.91) > Pb (124.86) > Ni (68.89) > Cd (5.58). The contamination factor underscores elevated pollution for Zn and Pb (marker elements) and pollution load index showed contamination in most of the sites. While considering health risk assessments, the Hazard Index (HI) for non-carcinogenic effects on both children and adults indicates values < 1. Carcinogenic effects possessed values in the appreciable category except for dermal exposure for Cd, where the values fell in the acceptable risk category, suggesting no immediate harm to the exposed population. The study postulates that the high pollution index levels may hint at potential future risk. The study also demonstrates the significance of risk assessment formulas for immediate health risk assessment
Review of Strategies to Control Air Pollution due to PFAS
No full textPer and polyfluoroalkyl substances (PFAS), also known as “forever chemicals” have emerged as the next environmental threat due to their persistence and challenges in capture and control. The water contamination aspect of the PFAS has been extensively researched, however, the emissions into the atmosphere are a growing concern due to their volatility, long-range transport potential, and resistance to degradation. As a result of discovery of air pollution pathways of PFAS due to industrial processes, consumer usage and waste treatment, researchers have been identifying innovative technologies to mitigate the PFAS related air pollution. This study reviews various types of existing technologies such as oxidation, absorption and adsorption. In addition, a review of emerging technologies such as non-thermal plasma treatment was also investigated and presented in this study. Key research gaps and opportunities for future innovation were identified and possibilities of multi-prong approach were investigated to mitigate PFAS associated air pollution
Modifying capacity of the Al–Cu–Zr master alloy with the nucleating-phase Al
No full textThis study examines the synthesis temperature and composition conditions of Al–Cu–Zr aluminides with a cubic L12-type lattice, where copper replaces 8–12% of aluminum. Copper stabilizes the cubic lattice of trialuminides, substituting up to 12 at.% Al. Aluminides with compositions (Al0.92Cu0.08)3Zr and (Al0.88Cu0.12)3Zr exhibit high crystallographic and structural similarity to the α-Al lattice. The alloy containing 36.28% Cu and 9.02% Zr forms metastable cubic-lattice aluminides, thermally stable at 850 °C. Additives of the complex Al-36.28%Cu-9.02%Zr master alloy grind aluminum grains two orders of magnitude finer than binary master alloys Al-2%Zr and Al-10%Cu with the same chemical composition
A Wasserstein-type metric for generic mixture models, including location-scatter and group invariant measures
No full textAbstract. In this article, we study Wasserstein-type metrics and corresponding barycenters for mixtures of a chosen subset of probability measures called atoms hereafter. In particular, this works extends what was proposed by Delon and Desolneux [10] for mixtures of Gaussian measures to other mixtures. We first prove in a general setting that for a set of atoms equipped with a metric that defines a geodesic space, the set of mixtures based on this set of atoms is a also geodesic space for the defined modified Wasserstein metric. We then focus on two particular cases of sets of atoms: (i) the set of location-scatter atoms and (ii) the set of measures that are invariant with respect to some symmetry group. Both cases are particularly relevant for various applications among which electronic structure calculations. Along the way, we also prove some sparsity and symmetry properties of optimal transport plans between measures that are invariant under some well-chosen symmetries
A constant pressure model for the warm absorber in Mrk 509
No full textContext. We present the analysis of 900 ks high-resolution RGS XMM-Newton observations of the nearby Seyfert galaxy Mrk 509 with the use of a self-consistent warm absorber (WA) model. We took a physically motivated approach to the modeling of the WA as a stratified medium in a constant total pressure (CTP) regime.
Aims. Powerful outflows are fundamental ingredients of any active galactic nucleus (AGN) structure. They can significantly affect the cosmological environment of their host galaxy. High-resolution X-ray data are best suited for outflow’s studies, and the observed absorption lines on heavy elements are evidence of the physical properties of an absorbing gas. Our models allow us to fit continuum shapes bounded together with the line profiles, which gives additional constraints on the gas structure of WA in this source. In this work, we benchmark and test the CTP model on the soft X-ray spectrum of Mrk 509.
Methods. A grid of synthetic absorbed spectra was computed with the photoionization code TITA