Absorber System Research Articles

An Improved PIN Diode Model Design for a Tunable Frequency Selective Absorber

An enhanced PIN diode model designed for a tunable frequency absorber is proposed, enabling continuous and adjustable absorption across the X-band frequency range. This new structure consists of four primary components: a frequency selective surface (FSS) layer, a dielectric substrate, an air spacer layer, and a metal substrate. Unlike previous designs, the PIN diode model introduced here offers significant advancements. It not only allows for the switching between absorption and reflection states but also enables precise tuning within the absorption state itself, providing a higher degree of control over the system’s performance. The unique arrangement of the PIN diodes in this design involves placing them between adjacent units of the structure. This strategic placement eliminates the need for complex and bulky bias networks, which are commonly used in conventional designs. As a result, it also minimizes the electromagnetic interference that often arises from bias lines, thereby improving the overall system efficiency and reliability. The proposed model, therefore, reduces the complexity of the absorbing system while enhancing its performance and tunability. Experimental results obtained through free-space measurements were conducted to validate the proposed design. The results show an excellent agreement with the simulation data, confirming that the improved structure can achieve continuous, tunable absorption with high precision. These findings suggest that the new PIN diode-based model could be a promising solution for a wide range of applications in dynamic frequency management and electromagnetic wave absorption systems.

Novel Nonaqueous PD/PZ/NMP Absorbent for Energy-Efficient CO2 Capture: Insights into the Crystal-Phase Regulation Mechanism of the Powdery Product.

Solid-liquid biphasic absorbents are a promising solution for overcoming the high-energy consumption challenge faced by liquid amine-based CO2 capture technologies. However, their practical applications are often hindered by difficulties in separating viscous solid-phase products. This study introduces a novel nonaqueous absorbent system (PD/PZ/NMP) composed of 4-amino-1-methylpiperidine (PD), piperazine (PZ), and N-methyl-2-pyrrolidone (NMP), engineered to produce easily separable powdery products. The PD/PZ/NMP absorbent achieves a CO2 loading of 0.86 mol-CO2/mol-amine, with 91% of CO2 concentrated in the solid phase. It demonstrates excellent cyclic stability, maintaining a regeneration efficiency of 91% after five regeneration cycles, and reduces energy consumption by 52% compared with the conventional monoethanolamine absorbent. Remarkably, PZ plays a crucial role in regulating the crystal composition of solid-phase products, transforming them from a viscous state to a crystalline powder. Characterization and density functional theory analysis explain the crystal-phase regulation mechanism: PD absorbs CO2 to form zwitterions (PDH+COO-), affording viscous products, and PZ forms protonated amines (PZH+) and monocarbamates (PZCOO-), which interact with PDH+COO- via hydrogen bonding to form a crystalline powder. These findings demonstrate the CO2 capture efficacy of the PD/PZ/NMP absorbent and provide a robust theoretical framework for fabricating solid-liquid biphasic absorbents tailored for practical applications.

Estimating the crashworthiness performances of crushboxes using artificial neural network

AbstractStudies on the development of energy absorbing systems that minimize vehicle chassis damage in traffic accidents are increasing day by day. Many designs have been made in the studies on crushboxes used to absorb the energy released in the event of an accident. These design works are quite costly and take a long time. In this study, to design crushboxes faster and more economically was estimated using artificial neural network. The input layer of the artificial neural network model consists of three different materials, thicknesses (between 0.8 and 2.2 mm) and three different initial speeds. In the artificial neural network model, 42 different models were created by changing the different training functions (training, trainlm and trainrp), transfer functions (tansig and logsig) and the number of neurons in the hidden layer (between 9 and 33). R2 and root mean square error (RMSE) methods were used to evaluate the efficiency of artificial neural network models. The training function was found to be highly accurate (R2: 0.99999 and root mean square error: 0.314727E‐05) when the training function was “trainlm” and the number of neurons in the hidden layer was 33. The training and testing results of the artificial neural network model show that artificial neural networks can be used to estimate the specific energy absorption/energy/peak crush force value of crushboxes.

Portable Absorbable Electrical Stimulation System for Enhanced Peripheral Nerve Repair

AbstractPeripheral nerve injury significantly impairs sensory and motor functions, leading to diminished quality of life. Traditional treatments like nerve suturing and grafting often have limited efficacy and require long recovery. Recent advances in electrical stimulation technology show promise in speeding nerve repair, but current devices usually require lengthy surgeries, risking secondary nerve injury from prolonged nerve exposure during electrode installation and removal. This study introduces a portable, absorbable electrical stimulation system (PAESS) that integrates a battery‐free, wirelessly powered flexible printed circuit board chip with a biodegradable organic electrode. PAESS enables multiple self‐administered nerve stimulation without the need for electrode installation or removal. Using animal models, its electrical performance, biocompatibility, and efficacy in nerve repair are evaluated. The findings indicate a considerable enhancement in the recovery of nerve function, as demonstrated by improved electrophysiological measurements, decreased muscle atrophy, and positive histological results. Transcriptomic analysis indicates that the PAESS initiates the nerve regeneration process. This research presents an innovative platform for electrical stimulation, laying the groundwork for exploring electrical parameters and their mechanisms. This may deepen understanding of nerve regeneration and foster innovation in therapies.

Developing an off-site bicarbonation absorber system to promote microalgal fixation of CO2 in exhaust gas from biogas upgrading

Developing an off-site bicarbonation absorber system to promote microalgal fixation of CO2 in exhaust gas from biogas upgrading

Numerical analysis of impact resistance mechanical properties of energy-absorbing columns under static and dynamic loads

To enhance the impact resistance of hydraulic columns, a theoretical analysis method was employed to develop a dynamic characteristic analysis model for conventional columns under impact loads. This model facilitated the derivation of key parameters such as equivalent stiffness, maximum retraction amount, and impact duration. A fluid-solid coupling model for the conventional column was constructed using finite element and coupled Eulerian-Lagrangian (CEL) methods. Subsequently, numerical simulation results were compared and analyzed against theoretical predictions. Based on this analysis, an energy-absorbing column was designed, and its fluid-solid coupling model was established to investigate its mechanical response under static and dynamic impact loads.The findings indicate that under a static load of 2000 kN, when superimposed with impact loads of 200 kJ, 400 kJ, and 800 kJ respectively, the peak impact forces on energy-absorbing columns are 89.20%, 91.72%, and 98.42% lower than those on normal columns. The yield displacements of energy-absorbing columns increase by 142.26%, 109.15%, and 108.41% compared to normal columns. Energy absorption in energy-absorbing columns is 152.11%, 171.80%, and 145.18% higher than in normal columns. Furthermore, initial velocities of energy-absorbing columns are consistently lower compared to normal columns. After reaching initial velocity, energy-absorbing columns exhibit reduced oscillations due to interactions between the energy absorber, column, and hydraulic fluid system under impact loads. Unlike normal columns, energy-absorbing columns mitigate stress concentration at the column head through interactions between the energy absorber, emulsion, and column. Additionally, the impact resistance time of energy-absorbing columns is 2.19, 1.64, and 1.85 times longer than that of normal columns.Energy-absorbing columns outperform conventional columns across six metrics: peak impact force, column yield displacement, energy absorption, column movement speed, stress distribution, and impact resistance time, demonstrating superior mechanical properties in impact resistance.

Enhancing railway noise reduction through advanced multilayer acoustic absorbent systems with tunable resonators

Railway noise poses a significant environmental challenge, prompting the need for effective mitigation strategies. In response, noise barriers are often employed to reduce noise near railways. This research focuses on the use of porous materials, more specifically porous concrete, for acoustic absorption, particularly in the context of railway noise reduction. A novel approach is proposed, wherein porous multilayer metamaterial systems are developed, with each layer's macroscopic parameters strategically optimized to enhance the overall sound absorption curve. Additionally, to broaden the frequency range of noise attenuation, tunable resonators are seamlessly integrated into the multilayer system. The analytical framework for analyzing both the multilayer system and resonators involves employing equivalent fluid models and the analytical transfer matrix method. Linear regressions were employed to establish relationships between porosity, density, and other macroscopic parameters, enabling the derivation of the sound absorption curve solely from these parameters. Through systematic optimization and integration of resonators, it is expected that, the proposed approach demonstrates significant advancements in railway noise reduction efficacy across a wide frequency range. This research aims to contribute to the development of more efficient and versatile acoustic absorbent systems for mitigating railway noise pollution.

Implementation of Active Noise Canceling for Noise Reduction using Embedded System

Abstract This paper presents the utilization of active noise canceling (ANC) technology using an embedded system for a sound insulation box. The ANC system for the insulation box is designed to replace conventional heavyweight passive sound absorber systems. A feedback filtered-x least mean square (FxLMS) algorithm is utilized to create the opposing-noise signal to counteract the incoming noise entering the box, so that reducing the noise level inside the box. In our previous work, we delved into a similar topic of using ANC for a sound insulation box, but the prior system had limited performance due to its inability to operate in real time. In this study, the FxLMS algorithm is implemented on an ARM Cortex-based microcontroller development board. A feedback structure is utilized, with an error microphone positioned in the middle of the box The ANC system’s capability was evaluated for pure tone noise in the frequency range of 63 Hz to 630 Hz. The experimental findings indicate that the ANC system has the capability to cut back the noise level up to 4 dB for some frequencies.

Silicon porous disc featured parabolic trough collector functioned with paraffin: Thermal performance study

Silicon porous disc featured parabolic trough collector functioned with paraffin: Thermal performance study

3D X-ray Tomography Analysis of Mg–Si–Zn Alloys for Biomedical Applications: Elucidating the Morphology of the MgZn Phase

Temporary metal implants, made from materials like titanium (Ti) or stainless steel, can cause metabolic issues, raise toxicity levels within the body, and negatively impact the patient’s long-term health. This necessitates a subsequent operation to extract these implants once the healing process is complete or when they are outgrown by the patient. In contrast, medical devices fabricated from absorbable alloys have the advantage of being biodegradable, allowing them to be naturally absorbed by the body once they have fulfilled their role in facilitating tissue healing. Among the various absorbable alloy systems studied, magnesium (Mg) alloys stand out due to their biocompatibility, mechanical properties, and corrosion behavior. The existing literature on absorbable Mg alloys highlights the effectiveness of silicon (Si) and zinc (Zn) additions in improving mechanical properties and controlling corrosion susceptibility; however, there is a lack of comprehensive quantitative morphological analysis of the intermetallic phases within these alloy systems. The quantification of the complex morphology of intermetallic particles is a challenging task and has significant implications for the micromechanical properties of the alloys. This study, therefore, aims to introduce a robust set of morphometric parameters for evaluating the morphology of intermetallic phases within two as-cast Mg alloys with Si and Zn additions. X-ray Computed Tomography (XCT) was used to capture the 3D tomographic data of the alloys, and a novel pair of morphological parameters (ratio of convex hull to particle volume and convex hull sphericity) was applied to the 3D tomographic data to assess the MgZn phase formed in the two alloys. In addition to the impact of composition, the effect of solidification rate on the morphological parameters was also studied. Furthermore, Scanning Electron Microscopy (SEM) and Energy-Dispersive Spectroscopy (EDS) were employed to gather detailed 2D microstructural and compositional information on the intermetallics. The comprehensive characterization reveals that the morphological complexity and size distribution of the MgZn phase are influenced by both compositional changes and the solidification rate. However, the change in MgZn intermetallic particle morphology with size was found to follow a predictable trend, which was relatively agnostic of the chosen casting conditions.

Design and experiment of a crawling-inchworm-type self-tuned dynamic vibration absorber based on silicone gel materials

Based on the different body configurations caused by varying head-to-tail distances exhibited by crawling inchworms during locomotion, this paper proposes a crawling-inchworm-type self-tuned dynamic vibration absorber (DVA) based on silicone gel materials for reducing low-frequency vibration. The proposed DVA was designed and developed by employing a magnetic hanging design with movable features, a span adjustment design with an embedded stepper motor, and a real-time control design using a microcontroller. First, a finite element simulation model was established to analyze the main structure of the self-tuned DVA using the finite element method. The frequency-shifting characteristics of the absorber were obtained by identifying the actuating modes that are sensitive to the hanging span. Second, based on the frequency-shifting characteristics of the self-tuned DVA, an absorber control system was designed by introducing a short-time Fourier transform and PID algorithm to achieve autonomous frequency adjustment of the DVA. Finally, the self-tuned absorption effects of the prototype self-tuned DVA were tested through a series of experiments, which confirmed its excellent self-tuned vibration absorption capability within the low-frequency range.

Investigation of CO2 Rapid Phase Change Absorbent System Based on Amino Acid Salts and Ether Solvents

Investigation of CO₂ Rapid Phase Change Absorbent System Based on Amino Acid Salts and Ether Solvents

Vibration control of FG-pipe conveying fluid using a nonlinear absorber with nonlinear damping in longitudinal direction

Vibration control of FG-pipe conveying fluid using a nonlinear absorber with nonlinear damping in longitudinal direction

The rich galactic environment of a H2-absorption-selected quasar

We present the first Very Large Telescope (VLT) Multi Unit Spectroscopic Explorer (MUSE) observations of a quasar featuring a proximate molecular absorption system, SDSS J125917.31+030922.5. The proximate damped Lyα absorption acts as a natural coronagraph, removing the quasar emission over ∼40 Å in wavelength, and allows us to detect extended Lyα emission without the necessity of subtracting the quasar emission. This natural coronagraph permits the investigation of the quasar environment down to its inner regions (r < 20 kpc), where galaxy interactions or feedback processes should have the most noticeable effects. Our observations reveal a dense environment, with a highly asymmetric Lyα emission within 2″ (∼15 kpc), possibly shaped by a companion galaxy, and a southern extension of the nebulae to about 50 kpc, with rotation-like kinematic signature. The width of the Lyα emission is broadest closer to the quasar, indicating perturbed kinematics as expected if interactions and significant gas flows are present. The foreground absorbing system itself is redshifted by ≈400 km/s relative to the background quasar, and therefore is likely arising from gas moving toward the quasar. Finally two additional Lyα emitters are detected with > 10σ significance at 96 and 223 kpc from the quasar, making this field overdense relative to other similar observations of quasars at z ∼ 3. Our results support the hypothesis that quasars with proximate neutral and molecular absorption trace rich environments where galaxy interactions are at play and motivates further studies of H2-selected quasars to shed light on feeding and feedback processes.

All-optical logic gates based on optimized coherent perfect absorber and fuzzy inference system

All-optical logic gates (AO-LGs) are key elements that play a pivotal role in the development of future all-optical computing and all-optical computers. In this paper, benefiting from particle swarm optimization (PSO), an optimized metasurface unit cell in the far-infrared (FIR) frequency band is presented as the basis of four port controlling light with the light system. This system, known as coherent perfect absorption (CPA), could be applied as AO-LGs in certain conditions. NOT, AND, OR, NAND, NOR, XOR, and XNOR logic gates can be implemented with the proposed method. The remarkable innovation of this article is the use of a fuzzy inference system (FIS) instead of a crisp threshold. Different calculated parameters like extinction ratio (ER = 96.2 dB), contrast ratio (CR = 99.54 dB), amplitude modulation (AM = 0.7 dB), and eye-opening (EO = 99%), besides the possibility of utilizing the proposed system for various kind of CPA films, prove the impressive effects of FIS applying as a novelty in this work. Small dimensions and low power consumption are other characteristics of the proposed method that are obtained as a result of using optimized metasurface-based CPA.

Aspen plus-based techno-economic assessment of a solar-driven calcium looping CO2 capture system integrated with CaO sorbent reactivation

Aspen plus-based techno-economic assessment of a solar-driven calcium looping CO2 capture system integrated with CaO sorbent reactivation

Double diffraction imaging of x-ray induced structural dynamics in single free nanoparticles

Because of their high photon flux, x-ray free-electron lasers (FEL) allow to resolve the structure of individual nanoparticles via coherent diffractive imaging (CDI) within a single x-ray pulse. Since the inevitable rapid destruction of the sample limits the achievable resolution, a thorough understanding of the spatiotemporal evolution of matter on the nanoscale following the irradiation is crucial. We present a technique to track x-ray induced structural changes in time and space by recording two consecutive diffraction patterns of the same single, free-flying nanoparticle, acquired separately on two large-area detectors opposite to each other, thus examining both the initial and evolved particle structure. We demonstrate the method at the extreme ultraviolet (XUV) and soft x-ray Free-electron LASer in Hamburg (FLASH), investigating xenon clusters as model systems. By splitting a single XUV pulse, two diffraction patterns from the same particle can be obtained. For focus intensities of about 2×1012 W cm−2 we observe still largely intact clusters even at the longest delays of up to 650 picoseconds of the second pulse, indicating that in the highly absorbing systems the damage remains confined to one side of the cluster. Instead, in case of five times higher flux, the diffraction patterns show clear signatures of disintegration, namely increased diameters and density fluctuations in the fragmenting clusters. Future improvements to the accessible range of dynamics and time resolution of the approach are discussed.

Simple Mechanism for Optimal Light-Use Efficiency of Photosynthesis Inspired by Giant Clams

In photosymbiotic giant clams, vertical columns of single-celled algae absorb sunlight that has first been forward scattered from a superficial layer of light-scattering cells called iridocytes. In principle, this arrangement could lead to a highly efficient system but it has been unclear how to calculate a productivity denominator to normalize the performance of the system. Inspired by the geometry observed in the clam, we have created an analytical model that calculates the idealized performance of a system with a geometry similar to the clam. In our model, photosynthesis-irradiance behavior obeys that of algal cells isolated from clams. Using a standard rate of eight photons of photosynthetically active radiation required to create one molecule of O2, we find that a fixed geometry of the “light-dilution” strategy employed by the clams can reach a quantum efficiency of 43% relative to the solar resource in intense tropical sunlight. In comparing the performance of the model to published photosynthesis-irradiance relations of living clams, we have observed that the living system easily exceeds the performance of the static model. Therefore, we have next considered a model in which the system geometry changes dynamically to optimize the quantum efficiency as a function of the solar irradiance. In this scenario, with changes in irradiance typical of a sunny tropical day, the performance of the model was consistent with that of large mature living clams and had a quantum efficiency of 67%. We also show that a similar dynamic modulation of the clam-tissue geometry could plausibly occur in the living animals. We have considered the possibility that efficiency gains in the living system could also occur via further optimization of per-cell absorbance of multiply scattered light within the highly absorbing system. However, a numerical model of radiative transfer within clam tissue that captures realistic multiple scattering has not located efficiency gains relative to the simpler single-pass analytical model. Therefore, we infer that additional resource efficiency over the dynamic, large-clam-like model would require nontrivial organization among cells at small length scales. We also observe that boreal spruce forests coupled to atmospheric haze may realize the same scale-invariant scattering-and-absorbance strategy as the clams but at a different, larger, length scale. Given these results, our model may demonstrate the maximum realizable light-use efficiency of a large photosynthetic system relative to the solar resource. The general principles here also readily generalize to any photosynthetic cell type or organic photoconversion material and solar-irradiance regime. They could therefore provide inspiration both for engineering novel efficient photoconversion processes and materials and inform optimal land-use estimates for efficient industrial biomass production. Published by the American Physical Society 2024

Efficiency Analysis of Hybrid Extreme Regenerative with Supercapacitor Battery and Harvesting Vibration Absorber System for Electric Vehicles Driven by Permanent Magnet Synchronous Motor 30 kW

This research presents an approach to the hybrid energy harvesting paradigm (HEHP) based on suspended energy harvest. It uses a harvesting vibration absorber (HVA) with an SC/NMC-lithium battery hybrid energy storage paradigm (SCB-HESP) equipped regenerative braking system (SCB-HESP-RBS) for electric vehicles 2 tons in gross weight (MEVs) driven by a 30 kW permanent magnet synchronous motor (PMSM). During regenerative braking, the ANN mechanism controls the RBS to adjust the switching waveform of the three-phase power inverter, and the braking energy transfers to the energy storage device. Additionally, a supercapacitor (SC) equipped with HVA can absorb energy from vehicle vibrations and convert it into electrical energy. The energy-harvesting efficiency of MEV based on SCB-HESP-RBS using HVA suspended energy harvesting enhances the efficiency maximum to 50.58% and 15.36% in comparison to MEV with only-HVA and SCB-HESP-RBS, respectively. Further, the MEV with SCB-HESP-RBS using HVA has a driving distance of up to 247.34 km (22.5 cycles) when compared with SCB-HESP-RBS (214.40 km, 19.5 cycles) and only-HVA (164.25 km, 15 cycles).

Amino acids to reduce the escape of organic amines in the CO2 capture process

Amino acids to reduce the escape of organic amines in the CO2 capture process