Three-dimensional Cavity Research Articles

Robust Control Strategy of Acoustic Micro Robots Based on Fuzzy System.

This study presents a robust control strategy for acoustic micro robots utilizing a novel interval type-three fuzzy system. Micro robots driven by acoustic forces face significant challenges in fluid environments due to complex nonlinearities, uncertainties, and disturbances. To address these issues, we propose a control framework that combines fuzzy logic and sliding mode control to enhance the stability and trajectory tracking performance of micro robots under varying fluid conditions. The interval type-3 fuzzy logic system provides increased robustness by better handling external disturbances and uncertainties compared to the robustness of the traditional methods. The experimental results from one-dimensional, two-dimensional, and three-dimensional fluid cavities demonstrate that the proposed control method significantly improves tracking accuracy, reducing the errors in complex environments. This control framework offers promising potential for the precise manipulation of micro robots in biomedical applications and other microfluidic systems. The minimum trajectory tracking control mean square error is 12.82 μm.

Sound Insulation Characteristic Analysis of Corrugated Core Sandwich Panel by Using Differential Quadrature Finite Element Method

This paper proposes a universal vibroacoustic coupling theoretical analysis model for investigating the sound insulation characteristic of corrugated core sandwich panel (CCSP) under different boundary conditions. The vibroacoustic coupling model consists of CCSP (structural field) and two three-dimensional acoustic cavities which simulate the incident sound field and accept the sound field, respectively. Based on first-order shear deformation plate and shell theories and acoustic theory, the dynamic model of CCSP and three-dimensional acoustic cavities are established by employing the differential quadrature finite element method in conjunction with the energy principle. The coupling of CCSP and three-dimensional acoustic cavities is realized by the velocity continuity condition at the acoustic–structure interfaces. The validation of the vibroacoustic coupling model is verified by comparing the results calculated by the established model with the corresponding results calculated by ABAQUS. The influence of model parameters on the vibroacoustic characteristic of vibroacoustic coupling model is investigated systematically for determining the critical structure parameters which have influence on the vibroacoustic behaviors. The effect of critical structure parameters on the sound insulation characteristic of CCSP is analyzed systematically for the optimization of the sound insulation performance of CCSP and provides theoretical basis and technique guidance.

THE COOLING EFFECT OF COMBUSTOR EXIT LOUVER SCHEME ON A TRANSONIC NOZZLE GUIDE VANE ENDWALL

Abstract The ever-increasing combustor exit temperature in modern turbine engine designs raises challenges for the nozzle guide vane cooling. Due to the complexity of NGV cooling design, the cooling effect from the upstream combustor cooling features can prove valuable. This study investigates, experimentally and numerically, the cooling effect of a louver cooling scheme near the combustor exit on the NGV endwall. The wind tunnel testing and CFD simulation are carried out with engine-representative conditions of an exit Mach number of 0.85, an exit Reynolds number of 1.5 × 106, an inlet turbulence intensity of 16%, and a density ratio of 2.1. Various coolant mass flow ratios from 1% to 4% are tested to demonstrate the effect of the coolant rate. For the geometry studied, the results found a critical mass flow ratio between 1%~2%. The coolant forms a uniform film only by exceeding this value to provide good coverage upstream of the NGV passage inlet. As for the cooling of the NGV passage, the mass flow ratio of the range investigated is insufficient for desirable cooling performance. The pressure side endwall proves most difficult for the coolant to reach. In addition, the fishmouth cavity at the combustor-NGV passage causes a three-dimensional cavity vortex that transports the coolant in the pitch-wise direction. The transport pattern is dependent on the coolant mass flow ratio. Therefore, the authors propose combining this louver scheme with the upstream jump cooling scheme for a desirable NGV cooling system.

GPU parallel implementation of a finite volume lattice Boltzmann method for incompressible flows

This work presents a graphics processing units (GPU) parallel algorithm of a cell-centered finite volume lattice Boltzmann method (FVLBM) on unstructured meshes. In the present GPU parallel algorithm, the parallelization is performed in the physical space. To reduce the frequency of GPU memory accesses, this algorithm develops coalesced access to GPU memory. In addition, to avoid the race for resources leading to data anomalies, such as dirty read or phantom read etc., and the double counting for flux calculation, the efficient face-based data structure often used for flux calculation in cells in the central processing unit (CPU) version of FVLBM is modified into a face-based data structure used for the fluxes on all faces, followed by a cell-based loop for the final residuals in all cells. Therefore, the proposed GPU parallel algorithm does not need to use the resource lock and retains the high efficiency of the face-based data structure in the fluxes computation to enhance its’ parallel efficiency. Additionally, to demonstrate the computational efficiency of the proposed GPU parallel algorithm, various benchmark studies are performed in this work by the proposed parallel scheme on a double precision NVIDIA GeForce RTX 3090Ti GPU card, including (a) the lid-driven flow in a two-dimensional (2D) square cavity, (b) a 2D flow past a cylinder, and (c) the lid-driven flow in a three-dimensional (3D) cubic cavity. The numerical results show that the proposed GPU parallel algorithm can be as accurate as the original CPU serial scheme with 1 to 2 orders of speedup.

Strategies and Trade-Offs for Controllability and Memory Time of Ultra-High-Quality Microwave Cavities in Circuit Quantum Electrodynamics

Three-dimensional microwave cavity resonators have been shown to reach lifetimes of the order of a second by maximizing the cavity volume relative to its surface, using better materials, and improving surface treatments. Such cavities represent an ideal platform for quantum computing with bosonic qubits, but their efficient control remains an outstanding problem since the large mode volume results in less efficient coupling to nonlinear elements used for their control. Moreover, this coupling induces additional cavity decay via the inverse Purcell effect that can easily destroy the advantage of a long intrinsic lifetime. Here, we discuss conditions on, and protocols for, efficient utilization of these ultra-high-quality microwave cavities as memories for conventional superconducting qubits. We show that, surprisingly, efficient write and read operations with ultra-high-quality cavities do not require similar quality factors for the qubits and other nonlinear elements used to control them. Through a combination of analytical and numerical calculations, we demonstrate that efficient coupling to cavities with second-scale lifetime is possible with state-of-the-art transmon and superconducting nonlinear asymmetric inductive element devices and outline a route towards controlling cavities with even higher quality factors. Our work explores a potentially viable roadmap towards using ultra-high-quality microwave cavity resonators for storing and processing information encoded in bosonic qubits. Published by the American Physical Society 2024

Numerical and experimental investigation of the steam penetration in narrow channels during a dynamic steam sterilization cycle

The most challenging aspect of steam sterilization is the removal of all non-condensable gases (NCGs) from the autoclave. These gases prevent the effective killing of microorganisms, impairing the sterility of medical devices. Special cycles are performed to ensure the penetration of steam, even into the deepest passages. To better understand this process, numerical models were developed to determine the spatial distribution of steam within the chamber, including its penetration into narrow channels. These are the first models that can be used to accurately determine the flow within three-dimensional cavities during a dynamic sterilization cycle. To validate the model, an experiment was designed using direct tunable diode laser absorption spectroscopy at a wavelength of 1364 nm to measure the mole fraction of steam present at the end of an aluminum pipe at a temporal resolution of 1 s. This represents a pioneering application of this technique in the field of steam sterilization. This setup was designed for installation on any autoclave. Both simulation and experimental data exhibit good agreement over the entire pressure range (0.18–3.15 bar). The most interesting observation made during the study was the increase in the steam content at the end of the tube while a vacuum was generated. The numerical results show that the mole fraction of H2O increased from 0.53 to 0.63 over the course of a single vacuum phase. This phenomenon was attributed to a stronger diffusion effect combined with small pressure gradients during low pressures. This finding inspired the idea of taking the diffusion effect more into account when designing sterilization cycles in the future to make them more sustainable and effective. The presented methodologies and models represent an excellent basis for conducting more complex investigations in the future, such as those investigating the influence of condensation effects on steam penetration in cavities.

Investigating forced convection in porous media-filled cavities for designing supplementary passive cooling systems

This study aims to propose innovative passive cooling methods within the reservoir section of a closed-loop liquid cooling system. The techniques employed in this study include using a cold wall, a porous medium, varying inlet positions, and nozzles of different sizes and shapes. The effects of parameters associated with these techniques on outlet temperature reduction, pressure drop, and average Nusselt number (Nu¯) have been analyzed in detail. The reservoir section has been numerically modeled as a two-dimensional (2D) and a three-dimensional (3D) cavity. The numerical model implements mass, momentum, energy, and conservation equations for the Darcy model in the porous region. A fluid flow with Re=50 with a laminar generalized porous media modeling approach employing Brinkman’s and Forchheimer’s terms has been used. The optimized inlet position with respect to maximum cooling (55.60 K) and moderate pressure drop (2.30kPa) for the 2D cavity has been identified in this work for a given Darcy number and porosity. Results show that decreasing porosity improves convective heat transfer efficiency and increases pressure drop. Similarly, varying Darcy’s number affects heat transfer, with lower Da values resulting in reduced outlet temperature reduction and lower Nu¯, with higher pressure drop. A similar analysis was conducted for the 3D reservoir. The use of a converging nozzle can lead to an increase in cooling by 61.61% and 3.44% for the 2D and 3D reservoirs, respectively.

Visualization and quantitative evaluation of aerosol deposition using 3D-printed adult nose cavities

Local steroid medication is one of the most important treatment options for chronic rhinosinusitis. Regional deposition has a higher clinical value compared with total deposition in predicting treatment outcomes or evaluating adverse reactions. The goal of this project is to propose an effective technique for visualizing and quantifying aerosol deposition in a three-dimensional adult nasal cavity, and to verify the practicality of this method. Three-dimensional (3D) nasal cavity models were constructed from computed tomography (CT) scans of one post-operative rhinosinusitis subject using imaging software. The nasal cast was coated with a water-indicating paste and deposited with saline; a liquid dressing was added to visualize the progress. The quantity of liquid dressing was evaluated via HPLC and the liquid deposition was analyzed within the nasal cast cavity. Herein, 98.77 % of the particles generated by the nebulizer were over 5 μm, suggesting that most of the aerosol could effectively enter the nasal cavity instead of the lower respiratory system. The liquid dressing was mainly deposited in the nasal cavity, ethmoid sinus, and frontal sinus according to the visualization tests. HPLC results suggested that the main deposits were the frontal sinus (up to 41.80 %) as well as in the sphenoid sinus and ethmoid sinus (14.00 %). The large particle nebulizer (BM-TCA) generally led to better deposition in sinus areas when compared to the smaller particle nebulizer (PARI). This technology allows for in vitro testing of various types of nasal preparations and equipment under various test methods.

The effect of initial pressure and temperature on the flow in a three-dimensional cavity filled with paraffin/Cu nanostructure with a wavy lower wall and a movable upper wall using molecular dynamics simulation

Phase change materials (PCMs) are very suitable for the storage of thermal energy. Heat transfer plays a crucial role in many important industrial processes in today's industrial environment. Thus, it is crucial to examine and comprehend this occurrence properly. This work uses molecular dynamic simulation to examine the effect of initial pressure (IP) and temperature (Temp) on the thermal efficiency of phase change materials inside a three-dimensional cavity. The hollow contains paraffin/Cu nanoparticles and has a bottom wall with a wavy shape and an upper wall that can be adjusted. The results of the equilibration stage indicated that the kinetic and potential energies converge to 2100 eV and -95472.50 eV after 10 ns. Next, the results show that increasing IP resulted in the reduction of maximum velocity and Temp, which decreased from 0.0099 Å/ps and 898 K to 0.0090 Å/ps and 888 K. Furthermore, the results show that by increasing IP, the heat flux and thermal conductivity decrease from 9.95 W/m2 and 1.45 W/m.K to 8.89 W/m2 and 1.26 W/m.K. Conversely, as the initial Temp rose from 300 to 350 K, so did the velocity (0.0125 Å/ps) and Temp (990 K). Furthermore, the thermal conductivity and heat flux increased to 1.69 W/mK and 11.25 W/m2, respectively. This study reveals how molecular dynamics simulations provide insights into the effects of initial pressure and temperature on the flow and thermal behavior of a paraffin/copper nanostructure. The findings improve understanding of nanofluid and phase change material behavior, aiding the design of more efficient PCM-based systems for thermal energy storage and heat transfer applications. In general, the results of this research illuminate the complex relationship among IP, Temp, and thermal properties of phase change materials. This knowledge is of great significance as it can guide the formulation of novel approaches to enhance the thermal efficiency of these materials in practical applications.

Experimental and numerical investigation of pressure distribution in human upper airway passage before and after maxillary sinus surgery

Sinusitis, a common disease of the maxillary sinus, is initially managed with saline solution and medication, resulting in the resolution of symptoms within a few days in most cases. However, Functional Endoscopic Sinus Surgeries are recommended if pharmacological treatments prove ineffective. This research aims to investigate the effects of maxillary sinus surgery on the airflow field, pressure distribution within the nasal cavity, and overall ventilation. This study utilized a three-dimensional realistic nasal cavity model constructed from CT images of a healthy adult. Virtual surgery including uncinectomy with Middle Meatal Antrostomy, two standard procedures performed during such surgeries, was performed on the model under the supervision of a clinical specialist. Two replicas representing pre- and post-operative cases were created using 3D printing for experimental purposes. Various breathing rates ranging from 3.8 to 42.6 L/min were examined through experimental and numerical simulations. To ensure the accuracy of the numerical simulations, the results were compared to measured pressure data, showing a reasonable agreement between the two. The findings demonstrate that uncinectomy and Middle Meatal Antrostomy significantly enhance the ventilation of the maxillary sinuses. Furthermore, increasing inspiratory rates leads to further improvements in ventilation. The static pressure distribution within the maxillary sinuses remains relatively uniform, except in regions close to the sinus ostium, even after surgical intervention.

Derivation of Bose's Entropy Spectral Density from the Multiplicity of Energy Eigenvalues.

The modern textbook analysis of the thermal state of photons inside a three-dimensional reflective cavity is based on the three quantum numbers that characterize photon's energy eigenvalues coming out when the boundary conditions are imposed. The crucial passage from the quantum numbers to the continuous frequency is operated by introducing a three-dimensional continuous version of the three discrete quantum numbers, which leads to the energy spectral density and to the entropy spectral density. This standard analysis obscures the role of the multiplicity of energy eigenvalues associated to the same eigenfrequency. In this paper we review the past derivations of Bose's entropy spectral density and present a new analysis of energy spectral density and entropy spectral density based on the multiplicity of energy eigenvalues. Our analysis explicitly defines the eigenfrequency distribution of energy and entropy and uses it as a starting point for the passage from the discrete eigenfrequencies to the continuous frequency.

Numerical investigation of optical characterization of polycarbonate panels

Polycarbonate panels (PC panels) are state-of-the-art transparent insulating materials widely used in the construction industry due to their cavity structure, which provides exceptional thermal insulation and optimal optical performance. However, the inherent anisotropy of the three-dimensional cavity structure complicates radiative transfer and requires consideration of both azimuth and zenith angles in optical performance evaluation. This aspect has received limited attention in existing research. This study aims to accurately characterize the optical performance of PC panels through numerical simulations. A three-dimensional radiative transfer model based on the discrete ordinate radiation model is developed to solve the radiation transfer equation. The model's independency regarding mesh division, angular discretization, and accuracy is validated. The effects of incidence angle, geometric parameters, and optical properties of PC panels on optical performance are analyzed. The findings reveal a strong correlation between transmittance and absorption with variations in incident zenith and azimuth angles. The transmittance exhibits a consistent monotonic variation expressible as a rational bifunction. Notably, absorption peaks occur within specific solid angle ranges, with increased structural complexity resulting in heightened absorption and greater uncertainty. For conventional PC materials, maximum transmittance ranges from 46.9 % to 73 %, while maximum absorption ranges from 2.3 % to 13.5 %. Increasing absorption coefficients, refractive index, and surface scattering coefficients nonlinearly decrease transmittance while increasing absorption. Additionally, deviations in transmittance and absorption with azimuth angle amplify with an increase in non-horizontal structures. Sensitivity analysis indicates a significant influence of zenith angle on transmittance, and absorption coefficient predominantly affects absorption.

Undrained Bearing Capacity of Circular and Square Footings above Centric and Eccentric Three-Dimensional Cavities

Undrained Bearing Capacity of Circular and Square Footings above Centric and Eccentric Three-Dimensional Cavities

Exploring the complex interplay of factors in convective heat transfer: a comprehensive parametric analysis in three-dimensional permeable cavities

ABSTRACT This examination aimed to mathematically investigate the blended convective intensity movement inside a three-layered nook that consolidates a spinning roundabout chamber and an undulating permeable pit. Using the limited component technique (FEM), mathematical reproductions were executed across different boundaries, enveloping the Darcy number going from 10 − 5 to 10 − 2 Hartmann number (going from 0 to 100, the angular velocity between − 4000 and 4000, and the number of undulations in the permeable pit. The results, addressed through stream capability, isotherms, and isentropic forms, clarify the effect of these boundaries on movement, heat transport, and entropy age. The ends suggest that for an ideal upgrade of intensity move rates in a three-layered undulating permeable cavity with a pivoting chamber and exposed to an attractive field, explicit circumstances are suggested, a Darcy number more prominent than or equivalent to 10 − 2 , a Hartmann number of 0, undulation of the permeable pit (N = 3), and angular velocity surpassing 2000 in the stream heading. The study investigates convective heat transfer in a rotating cylindrical chamber, analyzing parameters like Darcy number, Hartmann number, and rotation speed for optimizing heat transfer systems in complex porous cavities. The optimal heat transfer occurs when the aspect ratio is fixed at 0.3 and porous media occupies 90% of the channel. A 150% enhancement in the Nusselt number can be observed when the cylinder’s rotational speed increases. The study also found that increasing angular velocity and Darcy number positively affects the Nusselt number. The research aims to understand the interplay of factors affecting convective heat transfer and fluid dynamics and offer practical implications for optimizing heat transfer systems. The novelty of this study lies in its thorough examination of convective heat transfer in a rotating cylinder-shaped porous cavity, focusing on factors like Darcy number, Hartmann number, rotation speed, and pit geometry. It provides insights for optimizing heat transfer efficiency in complex cavities and explores the impact of external magnetic fields and fluid dynamics. The study investigates the influence of parameters like Hartmann number, angular speed, and Darcy number on thermal and flow characteristics in a porous cavity filled with Fe3O4/MWCNT-water nanofluid, highlighting their importance for optimizing heat transfer efficiency.

Dynamic stiffness formulations for exact modal and dynamic response analysis of three-dimensional acoustic cavities in cylindrical coordinates

Exact dynamic stiffness (DS) models for three-dimensional (3D) cavities in cylindrical coordinates under any classical acoustic boundary conditions (BCs) are proposed in this paper. The paper first derives the exact general solutions that satisfy the governing differential equations. Then, these general solutions are used to develop the DS matrices for 3D cavities in cylindrical coordinates by substituting them into the acoustic pressure and normal velocity BCs. Subsequently, the Wittrick–Williams algorithm, along with the analytical expressions of the j0 count for various shaped cavities, is applied to compute natural frequencies. Finally, reliable and efficient techniques for dynamic response solution are employed. The DSM provides benchmark solutions for various 3D cavities. The convergence, universality, and efficiency of the proposed method in modal and response analysis are illustrated by comparing the results obtained using the DSM and FEM. The calculation time when using the DSM is only 0.1% of that when using the commercial finite element method, while maintaining the same accuracy. This research not only provides an effective technique for analyzing the cylindrical acoustic pressure field in engineering, but also establishes a foundation for the analysis of structural–acoustic coupling in tubular structures.

Gate-compatible circuit quantum electrodynamics in a three-dimensional cavity architecture

Gate-compatible circuit quantum electrodynamics in a three-dimensional cavity architecture

Controlled formation of three-dimensional cavities during lateral epitaxial growth

Epitaxial growth is a fundamental step required to create devices for the semiconductor industry, enabling different materials to be combined in layers with precise control of strain and defect structure. Patterning the growth substrate with a mask before performing epitaxial growth offers additional degrees of freedom to engineer the structure and hence function of the semiconductor device. Here, we demonstrate that conditions exist where such epitaxial lateral overgrowth can produce complex, three-dimensional structures that incorporate cavities of deterministic size. We grow germanium on silicon substrates patterned with a dielectric mask and show that fully-enclosed cavities can be created through an unexpected self-assembly process that is controlled by surface diffusion and surface energy minimization. The result is confined cavities enclosed by single crystalline Ge, with size and position tunable through the initial mask pattern. We present a model to account for the observed cavity symmetry, pinch-off and subsequent evolution, reflecting the dominant role of surface energy. Since dielectric mask patterning and epitaxial growth are compatible with conventional device processing steps, we suggest that this mechanism provides a strategy for developing electronic and photonic functionalities.

Investigation of free convection in a wavy trapezoidal porous cavity with MWCNT- Fe3O4/Water hybrid nanofluid under MHD effects: Galerkin finite element analysis

Our study focuses on numerically investigating natural convection within a three-dimensional trapezoidal cavity featuring a corrugated hot bottom wall, with a particular emphasis on enhancing heat exchange using a water-based hybrid nanofluid. Employing a steady-state regime assumption, the study considers laminar and incompressible three-dimensional flow. The Darcy-Forchheimer model is incorporated to account for inertial advection effects within the porous layer. Predictions of the thermal and hydrodynamic behaviors of the system are achieved by solving dimensionless equations utilizing the Galerkin Finite Element Method (GFEM). Notably, a range of influential parameters, including the volume fraction of nanoparticles (φ), Darcy number (Da) spanning from 10−5 to 10−2, Hartman number (Ha) across the range of 0–100, φ within the range of 0–0.08, porosity (ε) ranging from 0.2 to 0.9, and Rayleigh numbers (Ra) varying from 103 to 106 was explored. The investigation also evaluates the geometrical impact of the enclosure by considering undulation numbers (N) of the warm bottom ranging from 1 to 4. Our results provide novel quantitative insights. Specifically, we observe an inverse relationship between undulation number (N), Hartman number (Ha), and porosity (ε) with large Rayleigh (Ra) flows, significantly influencing effective heat transfer. Notably, this influence diminishes at lower Ra flows. At the highest Ra, we find that increasing Da, ε, and φ enhances the Nusselt number (Nuavg) by 26 %, 17 %, and 23.5 %, respectively. Conversely, increasing Ha and N reduces Nuavg by 13 % and 40 %, respectively. These findings highlight the nuanced interplay of parameters and offer valuable quantitative data for optimizing heat transfer processes in similar systems.

Flow Instabilities and Control Mechanisms in Cylindrical Cavities With Top Bounding Walls

Abstract Cavity flows studied over the past few decades have led to an increased understanding of the flow physics and instability modes in a range of configurations. While a large number of these studies focus on two-dimensional and three-dimensional rectangular/cuboidal cavities, significant variations are seen with three-dimensional cylindrical cavities with a top bounding wall. The present work details the flow physics of such cavities with a compressible (air) flow past the cavity at two pressure drops of 3850 Pa and 2000 Pa. Results from detached eddy simulations (DES) reveal the presence of the wake mode and shear layer instabilities, respectively, with modified dynamics and oscillatory modes owing to the top wall. In the interest of preventing mode switching with changes in operating conditions, which could lead to large-scale flow disruptions, a passive flow control technique is tested. The modified cavity (with a downstream ramp scaled by the size of shed structures) is seen to maintain the same mode throughout the range of operation offering valuable insights into design modifications for such cavities in practical settings.

Bifunctional electrocatalytic reduction performance of nitrogen containing biomass based nanoreactors loaded with Ni nanoparticles for oxygen and carbon dioxide

In the face of increasing energy demand, the approach of transformation that combines energy restructuring and environmental governance has become a popular research direction. As an important part of electrocatalytic reactions for gas molecules, reduction reactions of oxygen (ORR) and carbon dioxide (CO2RR) are very indispensable in the field of energy conversion and storage. However, the non-interchangeability and irreversibility of electrode materials have always been a challenge in electrocatalysis. Hereon, nickel and nitrogen decorated biomass carbon-based materials (Ni/N-BC) has been prepared by high temperature pyrolysis using agricultural waste straw as raw material. Surprisingly, it possesses abundant active sites and specific surface area as a bifunctional electrocatalyst for ORR and CO2RR. The three-dimensional porous cavity structure for the framework of biomass could not only provide a strong anchoring foundation for the active site, but also facilitate the transport and enrichment of reactants around the site. In addition, temperature modulation during the preparation process also optimizes the composition and structure of biomass carbon and nitrogen. Benefit from above structure and morphology advantages, Ni/N-BC-800 exhibits the superior electrocatalytic activity for both ORR and CO2RR simultaneously. More specifically, Ni/N-BC-800 exhibits satisfactory ORR activity in terms of initial potential and half wave potential, while also enables the production of CO under high selective. The research results provide ideas for the development and design of electrode materials and green electrocatalysts, and also expand new applications of agricultural waste in fields such as energy conversion, environmental protection, and resource utilization.