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Keywords = pressure chamber tests

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13 pages, 1671 KiB  
Article
A Leak Identification Method for Product Oil Pipelines Based on Flow Rate Balance: Principles and Applications
by Likun Wang, Qi Wang, Hongchao Wang, Min Xiong, Shoutian Jiao and Xu Sun
Processes 2025, 13(8), 2459; https://doi.org/10.3390/pr13082459 - 4 Aug 2025
Viewed by 193
Abstract
To address the data acquisition limitations of traditional flow balance methods that stem from insufficient flow rate measurements, this study establishes a pipeline flow calculation model based on the pressure data and proposes a pipeline leak identification approach for product oil pipelines. Firstly, [...] Read more.
To address the data acquisition limitations of traditional flow balance methods that stem from insufficient flow rate measurements, this study establishes a pipeline flow calculation model based on the pressure data and proposes a pipeline leak identification approach for product oil pipelines. Firstly, field leak tests are designed and conducted on a product oil pipeline in East China by discharging oil in a valve chamber to simulate the leak process. Subsequently, combining the Bernoulli equation with the Leapienzon formula, a calculation model is established for flow rate prediction using the pressure data monitored at the stations and valve chambers along the pipeline. By analyzing the instantaneous flow rate changes at each pipeline section and pressure drops at each station and valve chamber, a dual-parameter collaborative threshold is set based on the flow balance principle, and leaks are identified when both parameters exceed the threshold simultaneously. Finally, the proposed flow rate calculation model and leak identification method are validated with respect to the field test data. The results show that the flow rate model yields a relative error as low as 0.48%, and the leak identification method accurately captured all six leak events in the field test, indicating very good stability and accuracy, with great potential for leak identification and alarm systems for product oil pipelines in engineering applications. Full article
(This article belongs to the Special Issue Design, Inspection and Repair of Oil and Gas Pipelines)
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24 pages, 6757 KiB  
Article
Design and Testing of a Pneumatic Jujube Harvester
by Huaming Hou, Wei Niu, Qixian Wen, Hairui Yang, Jianming Zhang, Rui Zhang, Bing Xv and Qingliang Cui
Agronomy 2025, 15(8), 1881; https://doi.org/10.3390/agronomy15081881 - 3 Aug 2025
Viewed by 159
Abstract
Jujubes have a beautiful taste, and high nutritional and economic value. The planting area of dwarf and densely planted jujubes is large and shows an increasing trend; however, the mechanization level and efficiency of fresh jujube harvesting are low. For this reason, our [...] Read more.
Jujubes have a beautiful taste, and high nutritional and economic value. The planting area of dwarf and densely planted jujubes is large and shows an increasing trend; however, the mechanization level and efficiency of fresh jujube harvesting are low. For this reason, our research group conducted a study on mechanical harvesting technology for fresh jujubes. A pneumatic jujube harvester was designed. This harvester is composed of a self-regulating picking mechanism, a telescopic conveying pipe, a negative pressure generator, a cleaning mechanism, a double-chamber collection box, a single-door shell, a control assembly, a generator, a towing mobile chassis, etc. During the harvest, the fresh jujubes on the branches are picked under the combined effect of the flexible squeezing of the picking roller and the suction force of the negative pressure air flow. They then enter the cleaning mechanism through the telescopic conveying pipe. Under the combined effect of the upper and lower baffles of the cleaning mechanism and the negative-pressure air flow, the fresh jujubes are separated from impurities such as jujube leaves and branches. The clean fresh jujubes fall into the collection box. We considered the damage rate of fresh jujubes, impurity rate, leakage rate, and harvesting efficiency as the indexes, and the negative-pressure suction wind speed, picking roller rotational speed, and the inclination angle of the upper and lower baffles of the cleaning and selection machinery as the test factors, and carried out the harvesting test of fresh jujubes. The test results show that when the negative-pressure suction wind speed was 25 m/s, the picking roller rotational speed was 31 r/min, and the inclination angles of the upper and lower baffle plates for cleaning and selecting were −19° and 19.5°, respectively, the breakage rate of fresh jujube harvesting was 0.90%, the rate of impurity was 1.54%, the rate of leakage was 2.59%, and the efficiency of harvesting was 73.37 kg/h, realizing the high-efficiency and low-loss harvesting of fresh jujubes. This study provides a reference for the research and development of fresh jujube mechanical harvesting technology and equipment. Full article
(This article belongs to the Section Precision and Digital Agriculture)
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22 pages, 5830 KiB  
Article
Design of and Experimental Study on Drying Equipment for Fritillaria ussuriensis
by Liguo Wu, Jiamei Qi, Liping Sun, Sanping Li, Qiyu Wang and Haogang Feng
Appl. Sci. 2025, 15(15), 8427; https://doi.org/10.3390/app15158427 - 29 Jul 2025
Viewed by 138
Abstract
To address the problems of the time consumption, labor intensiveness, easy contamination, uneven drying, and impact on the medicinal efficacy of Fritillaria ussuriensis in the traditional drying method, the hot-air-drying characteristics of Fritillaria ussuriensis were studied. The changes in the moisture ratio and [...] Read more.
To address the problems of the time consumption, labor intensiveness, easy contamination, uneven drying, and impact on the medicinal efficacy of Fritillaria ussuriensis in the traditional drying method, the hot-air-drying characteristics of Fritillaria ussuriensis were studied. The changes in the moisture ratio and drying rate of Fritillaria ussuriensis under different hot-air-drying conditions (45 °C, 55 °C, 65 °C) were compared and analyzed. Six common mathematical models were used to fit the moisture change law, and it was found that the cubic model was the most suitable for describing the drying characteristics of Fritillaria ussuriensis. The R2 values after fitting under the three temperature conditions were all greater than 0.99, and the maximum was achieved at 45 °C. Based on the principle of hot-air drying, a drying device for Fritillaria ussuriensis with a processing capacity of 15 kg/h was designed. It adopted a thermal circulation structure of inner and outer drying ovens, with the heating chamber separated from the drying chamber. The structural parameters were optimized based on Fluent simulation analysis. After optimization, the temperature of each layer was stable at 338 K ± 2 K, and the pressure field and velocity field were evenly distributed. The drying process parameters of Fritillaria ussuriensis were optimized based on response surface analysis, and the optimal process parameters were obtained as follows: inlet temperature: 338 K (65 °C), inlet air velocity: 3 m/s, and drying time: 10 h. The simulation results showed that the predicted moisture content of Fritillaria ussuriensis under the optimal working conditions was 12.58%, the temperature difference of Fritillaria ussuriensis at different positions was within 0.8 °C, and the humidity deviation was about 1%. A prototype of the drying device was built, and the drying test of Fritillaria ussuriensis was carried out. It was found that the temperature and moisture content of Fritillaria ussuriensis were consistent with the simulation results and met the design requirements, verifying the rationality of the device structure and the reliability of the simulation model. This design can significantly improve the distribution of the internal flow field and temperature field of the drying device, improve the drying quality and production efficiency of Fritillaria ussuriensis, and provide a technical reference for the Chinese herbal medicine-drying industry. Full article
(This article belongs to the Section Mechanical Engineering)
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12 pages, 6639 KiB  
Article
Study of Space Micro Solid Thruster Using 3D-Printed Short Glass Fiber Reinforced Polyamide
by Haibo Yang, Zhongcan Chen, Xudong Yang, Chang Xu and Hanyu Deng
Aerospace 2025, 12(8), 663; https://doi.org/10.3390/aerospace12080663 - 26 Jul 2025
Viewed by 229
Abstract
To meet the rapid maneuverability and lightweight demands of micro-nano satellites, a space micro solid thruster using 3D-printed short glass fiber reinforced polyamide 6 (PA6GF) composites was developed. Thruster shells with wall thicknesses of 4, 3, and 2.5 mm were designed, and ground [...] Read more.
To meet the rapid maneuverability and lightweight demands of micro-nano satellites, a space micro solid thruster using 3D-printed short glass fiber reinforced polyamide 6 (PA6GF) composites was developed. Thruster shells with wall thicknesses of 4, 3, and 2.5 mm were designed, and ground ignition tests were conducted to monitor chamber pressure and shell temperature. Compared with conventional metallic thrusters, PA6GF composites have exhibited excellent thermal insulation and sufficient mechanical strength. Under 8 MPa and 2773 K ignition conditions, the shell thickness was reduced to 2.5 mm and could withstand pressures up to 10.37 MPa. These results indicate that PA6GF composites are well-suited for space micro solid thrusters with inner diameters of 15–70 mm, offering new possibilities for lightweight space propulsion system design. Full article
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11 pages, 7635 KiB  
Case Report
An Unusual Manifestation of HSV-1 Uveitis Transforming into an Acute Iris Transillumination-like Syndrome with Pigmentary Glaucoma: A Reminder of Treatment Pitfalls in Herpetic Uveitis
by Marin Radmilović, Goran Marić, Ante Vukojević, Mia Zorić Geber and Zoran Vatavuk
Life 2025, 15(8), 1164; https://doi.org/10.3390/life15081164 - 23 Jul 2025
Viewed by 271
Abstract
We report a case of herpes simplex virus type 1 (HSV-1) anterior uveitis evolving into an acute iris transillumination-like syndrome with secondary pigmentary glaucoma, highlighting diagnostic challenges and treatment considerations. A 61-year-old immunocompetent woman presented with unilateral anterior uveitis characterized by keratic precipitates [...] Read more.
We report a case of herpes simplex virus type 1 (HSV-1) anterior uveitis evolving into an acute iris transillumination-like syndrome with secondary pigmentary glaucoma, highlighting diagnostic challenges and treatment considerations. A 61-year-old immunocompetent woman presented with unilateral anterior uveitis characterized by keratic precipitates and mild anterior chamber inflammation. The condition was initially treated with topical and subconjunctival corticosteroids without antiviral therapy. After an initial resolution of symptoms, upon the cessation of treatment, the patient developed features resembling unilateral acute iris transillumination (UAIT) syndrome with elevated intraocular pressure, diffuse pigment dispersion, and progressive iris transillumination defects. Aqueous polymerase chain reaction (PCR) testing confirmed the presence of HSV-1. Despite the initiation of antiviral therapy, the condition progressed to severe pigmentary glaucoma, with unreliable intraocular pressure measurements due to prior LASIK surgery. Cataract extraction, pars plana vitrectomy, and Ahmed valve implantation were performed, with only partial recovery of visual acuity. This case illustrates that HSV-1 uveitis can mimic or transition into a UAIT-like syndrome, possibly due to steroid use without concurrent antiviral treatment, which may exacerbate viral replication and damage to the iris pigment epithelium. Aqueous PCR testing aids in differential diagnosis, but indicative medical history and clinical findings should remain instrumental. Clinicians should maintain a high index of suspicion for herpetic etiology in anterior uveitis cases and initiate prompt antiviral treatment to prevent potentially sight-threatening complications. Full article
(This article belongs to the Special Issue Vision Science and Optometry)
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22 pages, 7942 KiB  
Article
Research on the Influence of Impeller Oblique Cutting Angles on the Performance of Double-Suction Pumps
by Zhongsheng Wang, Xinxin Li, Jun Liu, Ji Pei, Wenjie Wang, Kuilin Wang and Hongyu Wang
Energies 2025, 18(15), 3907; https://doi.org/10.3390/en18153907 - 22 Jul 2025
Viewed by 180
Abstract
Double-suction centrifugal pumps are extensively employed in industrial applications owing to their high efficiency, low vibration, superior cavitation resistance, and operational durability. This study analyzes how impeller oblique cutting angles (0°, 6°, 9°, 12°) affect a double-suction pump at a fixed 4% trimming [...] Read more.
Double-suction centrifugal pumps are extensively employed in industrial applications owing to their high efficiency, low vibration, superior cavitation resistance, and operational durability. This study analyzes how impeller oblique cutting angles (0°, 6°, 9°, 12°) affect a double-suction pump at a fixed 4% trimming ratio and constant average post-trim diameter. Numerical simulations and tests reveal that under low-flow (0.7Qd) and design-flow conditions, the flat-cut (0°) minimizes reflux ratio and maximizes efficiency by aligning blade outlet flow with the mainstream. Increasing oblique cutting angles disrupts this alignment, elevating reflux and reducing efficiency. Conversely, at high flow (1.3Qd), the 12° bevel optimizes outlet flow, achieving peak efficiency. Pressure pulsation at the volute tongue (P11) peaks at the blade-passing frequency, with amplitudes significantly higher for 9°/12° bevels than for 0°/6°. The flat-cut suppresses wake vortices and static–rotor interaction, but oblique cutting angle choice critically influences shaft-frequency pulsation. Entropy analysis identifies the volute as the primary loss source. Larger oblique cutting angles intensify wall effects, increasing total entropy; pump chamber losses rise most sharply due to worsened outlet velocity non-uniformity and turbulent dissipation. The flat-cut yields minimal entropy at Qd. These findings provide a basis for tailoring impeller trimming to specific operational requirements. Furthermore, the systematic analysis provides critical guidance for impeller trimming strategies in other double-suction pumps and pumps as turbines in micro hydropower plants. Full article
(This article belongs to the Special Issue Optimization Design and Simulation Analysis of Hydraulic Turbine)
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23 pages, 11965 KiB  
Article
Research on the Impact of Labyrinth Seal Ring Tooth Profile on the Pressure Pulsation of Leakage Chambers in High-Speed Centrifugal Pumps
by Guodong Zhao, Jiahao Xu, Jie Lian, Yanpi Lin and Zuchao Zhu
Lubricants 2025, 13(7), 308; https://doi.org/10.3390/lubricants13070308 - 16 Jul 2025
Viewed by 287
Abstract
The gap seal ring is a critical component in high-speed centrifugal pumps. The leakage rate and performance of the pump are sensitive to variation in seal ring parameters. This study investigates the influence of seal ring tooth profile on the leakage flow of [...] Read more.
The gap seal ring is a critical component in high-speed centrifugal pumps. The leakage rate and performance of the pump are sensitive to variation in seal ring parameters. This study investigates the influence of seal ring tooth profile on the leakage flow of pump chambers. Numerical simulation and experimental tests are used to analyze the impact of four different tooth-height labyrinth seal ring structures on the pressure pulsation characteristics of pump leakage chambers. It can be concluded that the use of labyrinth seal rings can significantly reduce the pressure pulsation and leakage rate of pump chambers. For the Case 2 structure with a tooth height of 0.18 mm, the pressure pulsation in the pump chamber can be reduced by a maximum of 22.5%, and the leakage rate can be reduced by 41.1%. For the Case 3 structure with a tooth height of 0.23 mm, the pressure pulsation in the pump chamber can be reduced by a maximum of 30.3%, and the leakage rate can be reduced by 40.6%. The use of labyrinth seal rings significantly reduces the pressure pulsation intensity of the impeller surfaces, which improves the force stability of the high-speed centrifugal pump impeller. This study is helpful in providing theoretical support for the design of labyrinth seal rings in high-speed centrifugal pumps. Full article
(This article belongs to the Special Issue Recent Advances in Sealing Technologies)
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17 pages, 6868 KiB  
Article
Development of a Throttleable 6 kN H2O2/Butyl Alcohol Rocket Engine
by Zbigniew Gut, Adrian Parzybut and David Perigo
Aerospace 2025, 12(7), 617; https://doi.org/10.3390/aerospace12070617 - 8 Jul 2025
Viewed by 445
Abstract
The increasing demand for versatile and sustainable propulsion systems has intensified research into green propellants and advanced thrust modulation technologies. This study presents the development and testing of a throttleable rocket engine utilizing 98% hydrogen peroxide by mass as the oxidizer and butyl [...] Read more.
The increasing demand for versatile and sustainable propulsion systems has intensified research into green propellants and advanced thrust modulation technologies. This study presents the development and testing of a throttleable rocket engine utilizing 98% hydrogen peroxide by mass as the oxidizer and butyl alcohol (as isomers n-butanol) as the fuel. Combining the environmental benefits of green propellants with variable thrust capabilities, the system addresses the challenges of modern space missions. Butyl alcohol was selected for its low toxicity, safety, storability, and favorable combustion performance, making it a strong candidate for future applications. The engine was designed to deliver a nominal thrust of 6 kN with the capability to throttle down to 1.2 kN. Experiments investigated the effects of pintle injector positions, supply pressures, and combustion chamber parameters on performance. Results demonstrated stable and efficient combustion across a wide operating range, highlighting the critical role of injector design and chamber geometry in ensuring consistent thrust and combustion efficiency. This research validates the potential of hydrogen peroxide and butyl alcohol as a sustainable propellant pair, particularly for planetary landers requiring precise thrust modulation for controlled descent. It marks a significant step in advancing sustainable propulsion technologies, contributing to the future of planetary exploration and interplanetary mission capabilities. Full article
(This article belongs to the Special Issue Green Propellants for In-Space Propulsion)
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21 pages, 4077 KiB  
Article
A Study on Ejector Structural and Operational Conditions Based on Numerical Simulation
by Gen Li, Yuan Liu, Dalin Wang, Xing Li, Daqian Liu, Zhongyu Hu, Bingyuan Hong, Xiaoping Li and Jing Gong
Processes 2025, 13(7), 2182; https://doi.org/10.3390/pr13072182 - 8 Jul 2025
Viewed by 282
Abstract
The Shenfu Gas Field faces challenges with uneven wellhead pressures, where low-pressure wells lose discharge capacity and high-pressure wells require throttling, leading to significant energy waste. Ejectors offer potential for energy recovery by utilizing high-pressure gas to boost low-pressure production. A computational fluid [...] Read more.
The Shenfu Gas Field faces challenges with uneven wellhead pressures, where low-pressure wells lose discharge capacity and high-pressure wells require throttling, leading to significant energy waste. Ejectors offer potential for energy recovery by utilizing high-pressure gas to boost low-pressure production. A computational fluid dynamics (CFD) model was developed using simulation software to simulate ejector performance. Parametric studies analyzed key structural parameters (mixing chamber length Lm, diameter Dm, nozzle spacing Lc, diffuser length Ld) and operational variables (compression ratio, working/entrained fluid pressures). Model validity was confirmed via grid independence tests and experimental comparisons (error < 10%). Network-level efficacy was verified using pipeline simulation software. Entrainment ratio (ε) and isentropic efficiency (η) exhibited non-linear relationships with structural parameters, with distinct optima depending on compression ratio. Dm had the strongest influence on ε. Higher compression ratios reduced ε, while increasing working fluid pressure or entrained fluid pressure improved ε. Optimal configurations were identified. Network simulations confirmed functional effectiveness, though efficiency diminished over production time. Ejector efficiency is highly sensitive to specific structural and operational parameters. Deployment in gas gathering networks is viable but most beneficial in early production stages. Full article
(This article belongs to the Section Energy Systems)
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28 pages, 53432 KiB  
Article
Deposition of Mesoporous Silicon Dioxide Films Using Microwave PECVD
by Marcel Laux, Ralf Dreher, Rudolf Emmerich and Frank Henning
Materials 2025, 18(13), 3205; https://doi.org/10.3390/ma18133205 - 7 Jul 2025
Viewed by 286
Abstract
Mesoporous silicon dioxide films have been shown to be well suited as adhesion-promoting interlayers for generating high-strength polymer–metal interfaces. These films can be fabricated via microwave plasma-enhanced chemical vapor deposition using the precursor hexamethyldisiloxane and oxygen as working gas. The resulting mesoporous structures [...] Read more.
Mesoporous silicon dioxide films have been shown to be well suited as adhesion-promoting interlayers for generating high-strength polymer–metal interfaces. These films can be fabricated via microwave plasma-enhanced chemical vapor deposition using the precursor hexamethyldisiloxane and oxygen as working gas. The resulting mesoporous structures enable polymer infiltration during overmolding, which leads to a nanoscale form-locking mechanism after solidification. This mechanism allows for efficient stress transfer across the interface and makes the resulting adhesion highly dependent on the morphology of the deposited film. To gain a deeper understanding of the underlying deposition mechanisms and improve process stability, this work investigates the growth behavior of mesoporous silica films using a multiple regression analysis approach. The seven process parameters coating time, distance, chamber pressure, substrate temperature, flow rate, plasma pulse duration, and pause-to-pulse ratio were systematically varied within a Design of Experiments framework. The resulting films were characterized by their free surface area, mean agglomerate diameter, and film thickness using digital image analysis, white light interferometry, and atomic force microscopy. The deposited films exhibit a wide range of morphological appearances, ranging from quasi-dense to dust-like structures. As part of this research, the free surface area varied from 15 to 55 percent, the mean agglomerate diameter from 17 to 126 nm, and the film thickness from 35 to 1600 nm. The derived growth model describes the deposition process with high statistical accuracy. Furthermore, all coatings were overmolded via injection molding and subjected to mechanical testing, allowing a direct correlation between film morphology and their performance as adhesion-promoting interlayers. Full article
(This article belongs to the Section Thin Films and Interfaces)
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20 pages, 4574 KiB  
Article
Experimental and Numerical Flow Assessment of the Main and Additional Tract of Prototype Differential Brake Valve
by Marcin Kisiel and Dariusz Szpica
Appl. Sci. 2025, 15(13), 7483; https://doi.org/10.3390/app15137483 - 3 Jul 2025
Viewed by 224
Abstract
The throughput of the pneumatic brake valve is a key parameter in ensuring fast and safe vehicle braking. The instantaneous value of this parameter determines the short response time of the system to an operator’s force. The scientific objective of this paper was [...] Read more.
The throughput of the pneumatic brake valve is a key parameter in ensuring fast and safe vehicle braking. The instantaneous value of this parameter determines the short response time of the system to an operator’s force. The scientific objective of this paper was to determine the throughput of brake valve tracts using numerical and experimental methods. These tracts are supposed to provide the tracking and acceleration function of the valve depending on the setting of the correction system. The first numerical method was based on polyhedral meshes using computational fluid dynamics (CFD) and Ansys Fluent software. The second research method—experimental tests on the author’s bench using the reservoir method—consisted of identifying throughputs based on pressure waveforms in the measurement tanks. The determined throughputs were averaged over the range of pressure differences tested and allowed the final calculation of the mass flow rate. The analysis of the obtained results showed an average discrepancy between the two research methods for both tracts, in which the flow in both directions was considered to be 9.43%, taking into account the use of a polyhedral numerical mesh ensuring high-quality results with an optimal simulation duration. The analysis of the pressure distribution inside the working chambers showed local areas of increased pressure and negative pressure resulting from the acceleration of the flow in narrow flow channels and the occurrence of the Venturi effect. Full article
(This article belongs to the Section Mechanical Engineering)
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23 pages, 6299 KiB  
Article
Multi-Valve Coordinated Disturbance Rejection Control for an Intake Pressure System Using External Penalty Functions
by Louyue Zhang, Duoqi Shi, Chao Zhai, Zhihong Dan, Hehong Zhang, Xi Wang and Gaoxi Xiao
Actuators 2025, 14(7), 334; https://doi.org/10.3390/act14070334 - 2 Jul 2025
Viewed by 255
Abstract
Altitude test facilities for aero-engines employ multi-chamber, multi-valve intake systems that require effective decoupling and strong disturbance rejection during transient tests. This paper proposes a coordinated active disturbance rejection control (ADRC) scheme based on external penalty functions. The chamber pressure safety limit is [...] Read more.
Altitude test facilities for aero-engines employ multi-chamber, multi-valve intake systems that require effective decoupling and strong disturbance rejection during transient tests. This paper proposes a coordinated active disturbance rejection control (ADRC) scheme based on external penalty functions. The chamber pressure safety limit is formulated as an inequality-constrained optimization problem, and an exponential penalty together with a gradient based algorithm is designed for dynamic constraint relaxation, with guaranteed global convergence. A coordination term is then integrated into a distributed ADRC framework to yield a multi-valve coordinated ADRC controller, whose asymptotic stability is established via Lyapunov theory. Hardware-in-the-loop simulations using MATLAB/Simulink and a PLC demonstrate that, under ±3 kPa pressure constraints, the maximum engine inlet pressure error is 1.782 kPa (77.1% lower than PID control), and under an 80 kg/s2 flow-rate disturbance, valve oscillations decrease from ±27% to ±5%. These results confirm the superior disturbance rejection and decoupling performance of the proposed method. Full article
(This article belongs to the Special Issue Actuation and Robust Control Technologies for Aerospace Applications)
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20 pages, 689 KiB  
Article
Efficiency of Ozone Applied in Flow and at Low Pressures in the Inactivation of Salmonella in Black Peppercorns (Piper nigrum L.) and the Effects of Ozone Treatment on Grain Quality and Essential Oil Composition
by Handina da Graça Lurdes Langa Massango, Lêda Rita D’Antonino Faroni, Maria Cristina Dantas Vanetti, Ernandes Rodrigues de Alencar, Marcus Vinícius de Assis Silva, Alessandra Aparecida Zinato Rodrigues, Paulo Roberto Cecon, Carollayne Gonçalves Magalhães, Daniele Almeida Teixeira and Letícia Elisa Rossi
Foods 2025, 14(13), 2215; https://doi.org/10.3390/foods14132215 - 24 Jun 2025
Viewed by 404
Abstract
Food contamination by Salmonella poses a significant public health risk, rendering products unfit for consumption. This study aimed to evaluate the efficiency of ozone gas (O3), applied in flow and at low pressures, in inactivating Salmonella on black peppercorns (Piper [...] Read more.
Food contamination by Salmonella poses a significant public health risk, rendering products unfit for consumption. This study aimed to evaluate the efficiency of ozone gas (O3), applied in flow and at low pressures, in inactivating Salmonella on black peppercorns (Piper nigrum L.). Samples were inoculated with a cocktail of four Salmonella serotypes and subjected to ozonation under flow or low-pressure conditions in a hypobaric chamber. For the flow treatment, ozone gas at 16 mg L−1 was humidified by passing it through a 40% (w/v) sodium chloride solution and applied for 2, 4, and 8 h. For the hypobaric chamber treatment, an inlet O3 concentration of 60 mg L−1 was used, with 10, 15, and 20 injections. The results showed that, under flow ozonation for 8 h, Salmonella was absent in 25 g of the sample. Ozone treatment increased pH, total titratable acidity (TTA), antioxidant activity (DPPH*), lightness (L*), color saturation (C*), total phenolic content (TPC), and the concentration of major essential oil compounds in all treatments. Under low-pressure ozonation, Salmonella persisted in all tested conditions, along with changes in color difference (∆E*), moisture content, TTA, DPPH*, L*, C*, pH, TPC, and the concentration of major essential oil compounds. The essential oil yield was not affected. Although the application of ozone at low pressures reduced Salmonella contamination, it was not sufficient for complete inactivation under the tested conditions. However, the flow-applied ozone treatment proved effective in the inactivation of Salmonella in black peppercorns. Full article
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21 pages, 3142 KiB  
Article
Design and Optimization of Modular Solid Rocket Grain Matching Multi-Thrust Performance Curve
by Wentao Li, Yunqin He, Yiyi Zhang and Guozhu Liang
Appl. Sci. 2025, 15(12), 6827; https://doi.org/10.3390/app15126827 - 17 Jun 2025
Viewed by 411
Abstract
Multi-thrust solid rocket motors are extensively used in tactical missiles. To effectively achieve the desired multi-thrust performance curve, firstly, the concept of modular grain is introduced. Star grain, slot grain, and end-burning grain are chosen as the fundamental templates, which can be flexibly [...] Read more.
Multi-thrust solid rocket motors are extensively used in tactical missiles. To effectively achieve the desired multi-thrust performance curve, firstly, the concept of modular grain is introduced. Star grain, slot grain, and end-burning grain are chosen as the fundamental templates, which can be flexibly combined to form an arbitrary multi-thrust performance curve. Secondly, a quadric approximation of the burning perimeter is derived, leading to the establishment of a governing equation for modular grain design. This equation ensures a close match between the resulting performance curve and the target one. Thirdly, the Nelder–Mead optimization algorithm is employed to maximize the propellant loading fraction and reduce the combustion chamber size. Finally, the method successfully produces single-thrust, dual-thrust, and triple-thrust grains. The results show that the relative maximum deviation between the designed and target pressure curves is less than 6.1%. Additionally, the best grain configuration is identified, which maximizes the propellant loading fraction while adhering to the throat-to-port ratio constraints. Consequently, the concept of modular grain offers a valuable approach for creating complex internal ballistic characteristics by combining simpler grain templates. This approach allows for fast, responsive motor conceptual design, prototyping, testing, and even production, thereby advancing the development of solid rocket motors in a more efficient and effective manner. Full article
(This article belongs to the Section Aerospace Science and Engineering)
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30 pages, 13022 KiB  
Article
Dynamic Mechanical Characteristics and Fracture Size Effect of Coal Sandstone Under High-Temperature and High-Strain Rate Coupling Action
by Ming Li, Fuqiang Zhu, Yiwen Mao, Fangwei Fan, Boyuan Wu and Jishuo Deng
Fractal Fract. 2025, 9(6), 381; https://doi.org/10.3390/fractalfract9060381 - 15 Jun 2025
Cited by 2 | Viewed by 488
Abstract
The deformation control of surrounding rock in the combustion air zone is crucial for the safety and efficiency of underground coal gasification (UCG) projects. Coal-bearing sandstone, a common surrounding rock in UCG chambers, features a brittle structure composed mainly of quartz, feldspar, and [...] Read more.
The deformation control of surrounding rock in the combustion air zone is crucial for the safety and efficiency of underground coal gasification (UCG) projects. Coal-bearing sandstone, a common surrounding rock in UCG chambers, features a brittle structure composed mainly of quartz, feldspar, and clay minerals. Its mechanical behavior under high-temperature and dynamic loading is complex and significantly affects rock stability. To investigate the deformation and failure mechanisms under thermal–dynamic coupling, this study conducted uniaxial impact compression tests using a high-temperature split Hopkinson pressure bar (HT-SHPB) system. The focus was on analyzing mechanical response, energy dissipation, and fragmentation characteristics under varying temperature and strain rate conditions. The results show that the dynamic elastic modulus, compressive strength, fractal dimension of fragments, energy dissipation density, and energy consumption rate all increase initially with temperature and then decrease, with inflection points observed at 400 °C. Conversely, dynamic peak strain first decreases and then increases with rising temperature, also showing a turning point at 400 °C. This indicates a shift in the deformation and failure mode of the material. The findings provide critical insights into the thermo-mechanical behavior of coal-bearing sandstone under extreme conditions and offer a theoretical basis for designing effective deformation control strategies in underground coal gasification projects. Full article
(This article belongs to the Section Engineering)
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