Uniform Control Research Articles

Agricultural spray drone deposition, Part 2: Operational height and nozzle influence pattern uniformity, drift, and weed control

Abstract Agricultural spray drone (ASD) use in managed turfgrass has been given limited attention in the scientific literature. Further, deposition patterns of ASD spray have been obscured in previous research by ambient wind, crop canopy interference, and limited sampling resolution. Using a continuous sampling method involving blue colorant and water sprayed over white Kraft paper that was assessed via digital image analysis of stain objects and referenced spectrophotometric analysis of extractant, deposition metrics were estimated across a 29.3-m transect perpendicular to an ASD or ground sprayer spray swath. The ASD applies very fine droplets that are highly concentrated with herbicide, similar to ultra-low volume treatments, that improved smooth crabgrass [Digitaria ischemum (Schreb.) Schreb. ex Muhl.] control compared to a ground sprayer when the ASD was operated at 2 m above the turf. Unfortunately, these very fine droplets also drift, leading to four times greater droplet density at distance of almost 12 m away from the targeted spray swath following an operational height of 10 m compared to that at 2 m. As ASD operational height increases, drift and effective swath width at 30% coefficient of variation uniformity increases while effective application rate, total deposition, and D. ischemum control by quinclorac herbicide decreased. Total deposition decreased 6% for each m increase in ASD operational height, likely due to evaporation. The potential losses due to evaporation is a serious consideration for ASD use that has received little attention in the scientific literature. Our data suggest that ASD operational height should be as low as possible, but modification of spray systems may be needed to improve homogeneity of spray pattern.

Development of Stable and Intensified Mixing Processes for the Precise and Scalable Production of Uniform Drug Delivery Nanocarriers.

Nanocarriers show great promise in drug delivery but face challenges in stability, uniformity, and morphology control. This work introduces an enhanced mixing process to overcome these obstacles, specifically aiming to produce consistently sized poly(lactic-co-glycolic) acid (PLGA) nanoparticles loaded with anti-tumor drugs. By innovatively integrating a pulsation dampener into the microfluidic channels of a continuous flow preparation system, the flow stability of piston pumps is improved nearly tenfold. Consequently, large-scale production of uniformly sized nanoparticles with customizable dimensions is achieved through nanoprecipitation. Furthermore, incorporating terminal double-bond-functionalized poly(lactic-co-glycolic acid)-b-poly(ethylene glycol)-maleimide (PLGA-PEG-Mal) enables these nanoparticles to act as nano-crosslinkers. This facilitates in situ crosslinking with thiolated hyaluronic acid via a spontaneous thiol-ene coupling reaction under physiological conditions, allowing for minimally invasive drug administration and significantly enhancing localized drug retention. The material's degradability in the presence of endogenous enzymes ensures controlled drug release, as demonstrated with the anti-tumor drug doxorubicin (DOX). Validation in a murine breast cancer model shows reduced toxicity and a substantial reduction in tumor weight compared to the free DOX group. These findings confirm the approach's effectiveness for breast cancer treatment and pave the way for innovative solutions in nanomedicine, providing a practical microfluidic mixing system for the design and large-scale production of nanomedicines.

Alternative and Herbal Pharmaceuticals

Alternative and herbal pharmaceuticals have gained significant attention in recent years as completing approaches to conventional medicine. This review explores the increasing interest in these organic remedies, meeting their productiveness, security, and supervisory challenges. Herbal medicines, arisen plants, and floral beginnings have existed secondhand for centuries in differing breedings for their healing features. The revival of interest in this natural device is compelled by one growing demand for whole and deterrent healthcare options. This review explains the pharmacological exercises of key herbaceous compounds, their machines of operation, and the clinical evidence advocating their use. Additionally, the unification of alternative healings into prevailing healthcare is checked, highlighting the significance of control of product quality, uniformity, and severe dispassionate experiments. While alternative and herbal pharmaceuticals offer hopeful benefits, they too pose challenges, containing instability in effectiveness and potential interactions accompanying unoriginal drugs. The review underlines the need for more inclusive research to confirm the efficacy and security of these analyses. In conclusion, alternative and herbaceous pharmaceuticals show a valuable addition to the healthcare arsenal, supported they are secondhand sensibly and as well evidence-located practices. Future research guidance and policy approvals are projected to embellish the unification of these healings into modern healing practice.

Investigating instabilities in magnetized low-pressure capacitively coupled RF plasma using particle-in-cell (PIC) simulations

The effect of a uniform magnetic field on particle transport in low-pressure radio frequency (RF) capacitively coupled plasma (CCP) has been studied using a particle-in-cell model. Three distinct regimes of plasma behavior can be identified as a function of the magnetic field. In the first regime at low magnetic fields, asymmetric plasma profiles are observed within the CCP chamber due to the effect of E→×B→ drift. As the magnetic field increases, instabilities develop and form self-organized spoke-shaped structures that are distinctly seen within the bulk plasma closer to the sheath. In this second regime, the spoke-shaped coherent structures rotate inside the plasma chamber in the −E→×B→ direction, where E→ and B→ are the DC electric and magnetic field vectors, respectively, and the DC electric field exists in the sheath and pre-sheath regions. The spoke rotation frequency is in the megahertz range. As the magnetic field strength increases further, the rotating coherent spokes continue to exist near the sheath. The coherent structures are, however, accompanied by new small-scale incoherent structures originating and moving within the bulk plasma region away from the sheath. This is the third regime of plasma behavior. The threshold values of the magnetic field between these regimes were found not to vary with changing plasma reactor geometry (e.g., area ratio between ground and powered electrodes) or the use of an external capacitor between the RF-powered electrode and the RF source. The threshold values of the magnetic field between these regimes shift toward higher values with increasing gas pressure. Analysis of the results indicates that the rotating structures are due to the lower hybrid instability driven by density gradients and electron-neutral collisions. This paper provides guidance on the upper limit of the magnetic field for instability-free operation in low-pressure CCP-based semiconductor deposition and etch systems that use the external magnetic field for plasma uniformity control.

Optimizing Classroom Lighting: Balancing Illuminance Uniformity and Glare Control with Led Technology

Indoor lighting environment significantly impacts students’ concentration and learning performance. Optimal lighting conditions enhance reading speed, accuracy, and comprehension abilities. In contrast, poor lighting conditions may lead to decreased concentration and increased errors in tasks. Therefore, classroom lighting is an important factor to consider in classroom design to optimize cognitive efficiency of students. Current classroom lighting solutions using LED systems have met European Norm (EN) standard in terms of illuminance and energy efficiency. However, although the issue of glare has been addressed, it has not been completely resolved. This study introduces a solution for glare-free classroom lighting that maintains uniformity while adhering to existing standards. This approach aims to create a visually comfortable learning environment, balancing effective lighting with glare reduction.

Control of thermal uniformity in microwave heating process by BPNN and adaptive particle swarm optimization

As China advances its green economy, innovative methods are being employed to enhance energy optimization and conservation within energy-intensive industries. Among these methods, microwave heating stands out due to its superior heating efficiency and lack of pollution. Nonetheless, uniform heating remains a challenge because the microwave absorption capacity of the heated medium varies with changes in heating time and temperature. To address this issue, an Adaptive Particle Swarm Optimization (APSO) neural network microwave system based on the Back Propagation Neural Network (BPNN) is proposed. This system leverages the fundamental principles of Particle Swarm Optimization (PSO), categorizing particle swarms into three types and iterating them through distinct processes to achieve optimal results. An APSO controller is designed based on system identification, adjusting the controller parameters according to the error between the real-time system output and the identification model. The feedback error is used as the fitness function in the PSO algorithm, continuously adjusting the weights and thresholds of the neural network. This intelligent control approach optimizes the microwave oven's input power to minimize the error between the actual temperature output and the identified temperature. The APSO controller is designed based on system identification, with the intelligently controlled microwave heating system adjusting its input power to minimize the error between the identified and actual temperature outputs. Unlike traditional Proportional Integral Differential (PID) and BPNN controllers, this approach calculates the output of the identified model and the error of the actual model, feeding this information back to the controller. The feedback error serves as the fitness function in the PSO algorithm, enabling continuous adjustment of the network's weights and thresholds to regulate the microwave equipment's output power, thereby ensuring the output temperature closely follows the preset temperature curve. Experimental results demonstrate that the actual output value of the system closely aligns with the original preset temperature curve, with a root mean square error of only 0.74. This designed identification and control system effectively achieves the desired outcome.

A Cross-Sectional Study of Pediatric Enhanced Recovery After Surgery in 23 Medical Institutions Across 17 Provinces and Cities in China

Objectives: The study aims to assess the current state of enhanced recovery after surgery (ERAS) in children across 23 medical institutions in China, providing data to support the management and policy-making of ERAS. Methods: In April 2023, a survey was conducted using convenience sampling among the pediatric surgical units of the National Medical Center's Pediatric Nursing Alliance. Data were collected using a specifically designed pediatric ERAS questionnaire, which included information on hospital demographics, surgical volumes, nurse-to-bed ratios, ERAS implementation status, and the primary challenges and obstacles in implementing ERAS programs. Results: The survey revealed that 21 out of the 23 hospitals (91.3%) had implemented ERAS programs, but only 6 (26.1%) had dedicated ERAS nurses. The challenges faced in implementing ERAS included the lack of ERAS clinical guidelines for specific diseases, the absence of unified quality control plans in hospitals, insufficient understanding of ERAS among medical staff, and the lack of hospital-level policy support. Conclusions: While the implementation of ERAS is a growing trend in pediatric surgical care, there is a significant shortage of specialized ERAS nurses, and various obstacles still hinder the widespread adoption of pediatric ERAS. Future research should focus on developing disease-specific ERAS clinical guidelines and establishing uniform ERAS quality control standards. Hospital administrators should provide policy support following ERAS implementation in their departments to facilitate the progression of ERAS.

H2O-based atomic layer deposition mechanism of aluminum oxide using trimethylaluminum

As a nanofabrication technology, atomic layer deposition (ALD) has been widely used in the fields of displays, microelectronics, nanotechnology, catalysis, energy and coatings. It demonstrates excellent conformality, large-area uniformity and precise control of the sub-monolayer film. Al2O3 ALD using trimethylaluminum (TMA) and water (H2O) as precursors is the most ideal ALD model system. In this work, the reactions of TMA and H2O with the surface have been investigated using density functional theory (DFT) calculations in order to obtain more information on the reaction mechanism of the complicated H2O-based ALD of Al2O3. In the TMA reaction, the methyl ligands can be eliminated and new Al-O bonds can be formed via ligand exchange reactions. In the H2O reaction, the methyl ligand on the surface can be further eliminated and new AlO bonds can be formed. Meanwhile, the coupling reactions between the surface methyl and hydroxyl groups can further form new AlO bonds and release CH4 or H2O to densify the Al2O3 film. These complicated reaction mechanisms of Al2O3 H2O-based ALD can provide theoretical guidance for the precursor design and ALD growth of other oxides and aluminum-based compounds.

Synthesis of ultra-high nitrogen doped hollow mesoporous carbon nanospheres via a universal solid–liquid interface self-assembly strategy

Functional mesoporous polymers, particularly their derived hollow mesoporous carbon spheres (HMCS), have introduced new opportunities in the field of energy storage. Traditional synthesis methods for HMCS typically rely on chemical etching, which often results in uniform chemical properties and structural control, thereby limiting their application in large-scale production and diverse fields. Therefore, in this study, we report a novel strategy for obtaining HMCS through the direct pyrolysis of a core matrix, melamine–formaldehyde resin (MF), to achieve hollow structures and ultra-high nitrogen doping (approximately 14.8 wt%). This new solid–liquid interfacial self-assembly approach enables the production of HMCS with remarkable electrochemical performance and practical application prospects in sodium-ion half-cells and full cells, thanks to the high nitrogen doping and unique structure. Notably, this strategy has been validated for its general applicability across 1D, 2D, and 3D solid matrices. Additionally, by adjusting the calcination temperature, this method allows for precise control over both the core size and nitrogen content of the egg yolk-shell structure mesoporous carbon spheres. In summary, the mesoporous materials developed in this study demonstrate flexibility, simplicity, versatility, and structural diversity, offering significant insights for future applications in energy storage and other fields.

Uncovering the hidden effects of repetitive subconcussive head impact exposure: A mega-analytic approach characterizing seasonal brain microstructural changes in contact and collision sports athletes.

Repetitive subconcussive head impacts (RSHI) are believed to induce sub-clinical brain injuries, potentially resulting in cumulative, long-term brain alterations. This study explores patterns of longitudinal brain white matter changes across sports with RSHI-exposure. A systematic literature search identified 22 datasets with longitudinal diffusion magnetic resonance imaging data. Four datasets were centrally pooled to perform uniform quality control and data preprocessing. A total of 131 non-concussed active athletes (American football, rugby, ice hockey; mean age: 20.06 ± 2.06 years) with baseline and post-season data were included. Nonparametric permutation inference (one-sample t tests, one-sided) was applied to analyze the difference maps of multiple diffusion parameters. The analyses revealed widespread lateralized patterns of sports-season-related increases and decreases in mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD) across spatially distinct white matter regions. Increases were shown across one MD-cluster (3195 voxels; mean change: 2.34%), one AD-cluster (5740 voxels; mean change: 1.75%), and three RD-clusters (817 total voxels; mean change: 3.11 to 4.70%). Decreases were shown across two MD-clusters (1637 total voxels; mean change: -1.43 to -1.48%), two RD-clusters (1240 total voxels; mean change: -1.92 to -1.93%), and one AD-cluster (724 voxels; mean change: -1.28%). The resulting pattern implies the presence of strain-induced injuries in central and brainstem regions, with comparatively milder physical exercise-induced effects across frontal and superior regions of the left hemisphere, which need further investigation. This article highlights key considerations that need to be addressed in future work to enhance our understanding of the nature of observed white matter changes, improve the comparability of findings across studies, and promote data pooling initiatives to allow more detailed investigations (e.g., exploring sex- and sport-specific effects).

Electrodeposited mesoporous TiO2 thin films and their application as the scalable electron transport layer for perovskite solar modules

In this study, we present the utilization of electrodeposited TiO2 mesoporous film (ED-MS-TiO2) as the electron transport layer (ETL) for perovskite solar cells, especially marking the first report of its application in perovskite solar modules. In the first part of this paper, we refine the electrodeposition process to enhance the porosity of the ED-MS-TiO2 thin film by elevating the ED temperature from room temperature to a mild 60 °C. Notably, the ED-MS-TiO2 ETL fabricated at 60 °C demonstrates comparable charge extraction capability and conversion efficiency to the benchmark ETL produced via the widely adopted spin-coating technique, achieving a remarkable 20.5 %. Furthermore, we demonstrate the immense superiority of the ED process in achieving uniformity in the preparation of large-area ETLs. Our current findings reveal that ED-MS-TiO2 exhibits exceptional uniformity control, with a thickness distribution of 122.69 ± 8.39 nm on a 100 cm² substrate, while its spin-coated counterpart exhibits poor thickness control, measuring 135.72 ± 50.72 nm. Moreover, perovskite solar modules (5 cm × 5 cm) employing the optimized ED-MS-TiO2 ETL attain an impressive efficiency of 15.63 %, surpassing counterparts utilizing spin-coated TiO2 ETLs, which achieve only 9.70 %.

Uniform Finite Time Safe Path Tracking Control for Obstacle Avoidance of Autonomous Vehicle via Barrier Function Approach

Uniform Finite Time Safe Path Tracking Control for Obstacle Avoidance of Autonomous Vehicle via Barrier Function Approach

Uniform Temperature Control for MEMS Gas Sensors Under Mismatch Conditions

Uniform Temperature Control for MEMS Gas Sensors Under Mismatch Conditions

A Practical Approach to Alignment and Error Feedback Control for Long-Span Arch Bridges

The accurate installation of long-span arch bridges’ arch ribs remains a challenge due to the complex calculations required for cable forces and arch rib displacements, as well as the significant influence of environmental and construction loads. In this study, we propose a practical approach to alignment and error feedback control for long-span arch bridges. Cable forces were optimized using multiple control objectives based on influence matrix principles. The impact of temperature on the next segment to be installed was analyzed using the metastatic GM(1, 1) model and fitting results. Several tunable parameters were employed to account for parameter errors and environmental interference. These parameters were adjusted based on the deviations between practical and theoretical alignments for different arch rib segments, achieving a model output of an offset-free-tracking arch rib structure. This technology was applied to monitor the construction of the Tian’e Longtan Grand Bridge. Compared to conventional alignment control approaches, the proposed method achieved excellent arch ring alignment after the closure of the high-accuracy arch rib and cable release, as well as effective control of cable force uniformity and tower deviation. Field measurement data indicate that the closing deviation of the arch ring is only 3 mm. This study provides a valuable reference for the construction control of long-span arch bridges.

Atomic Layer Deposition of Molybdenum Carbide Thin Films

AbstractThe development of deposition processes for metal carbide thin films is rapidly advancing, driven by their potential for applications including catalysis, batteries, and semiconductor devices. Within this landscape, atomic layer deposition (ALD) offers exceptional conformality, uniformity, and thickness control on spatially complex structures. This paper presents a comprehensive study on the thermal ALD of MoCx with MoCl5 and 1,4‐bis(trimethylgermyl)‐1,4‐dihydropyrazine [(Me3Ge)2DHP] as precursors, focusing on the functional properties and characterization of the films. The depositions are conducted at 200–300 °C and very smooth films with RMS Rq ≈0.3–0.6 nm on Si, TiN, and HfO2 substrates are obtained. The process has a high growth rate of 1.5 Å cycle−1 and the films appear to be continuous already after 5 cycles. The films are conductive even at thicknesses below 5 nm, and films above 18 nm exhibit superconductivity up to 4.4 K. In lieu of suitable references, Raman modes for molybdenum carbides and nitrides are calculated and X‐ray diffraction and X‐ray photoelectron spectroscopy are used for phase analysis.

Optimal design of air distribution systems in large indoor spaces during the construction of walls: A case study on liquefied natural gas terminal storage tanks

Efficiently organizing indoor airflow is crucial for optimizing the working environment in large-scale wall construction projects, particularly when constructing liquefied natural gas membrane tanks. This helps prevent membrane corrosion, optimize construction time, and mitigate future safety risks. However, due to their size, these tanks often experience air stratification, posing challenges in meeting simultaneous temperature, humidity, and uniformity requirements during construction. To effectively address this issue, this study developed Computational Fluid Dynamics models that numerically simulated three commonly used ventilation systems: displacement ventilation system, stratified ventilation system, and fabric duct air supply system. Laboratory experiments were conducted to validate the accuracy of numerical simulation. Additionally, response surface methodology (RSM) was used to determine optimal combinations of air supply parameters for superior environmental uniformity control. The findings indicate that the fabric air supply system is more suitable than displacement and stratified ventilation systems for achieving environmental uniformity control in large spaces. It can limit wall temperature nonuniformity coefficient up to 9 % during summer and provide better uniformity in air velocity during winter conditions. Moreover, under summer conditions, the optimal range for air supply speed is between 9.62 m/s - 11.22 m/s with temperatures ranging from 16 °C to 19 °C, while under winter conditions, the optimal range is between 18.3 m/s −19.3 m/s with temperatures ranging from 33.0 °C to 35.0 °C.The optimal design of the ventilation system is advantageous for various building construction scenarios with stringent temperature and humidity requirements, particularly for large-scale buildings.

Deep Reinforcement Learning-Enabled Distributed Uniform Control for a DC Solid State Transformer in DC Microgrid

Deep Reinforcement Learning-Enabled Distributed Uniform Control for a DC Solid State Transformer in DC Microgrid

High‐Quality Micropattern Printing by Complex‐Amplitude Modulation Holographic Femtosecond Laser

AbstractHolographic femtosecond laser printing technology is widely used in the fabrication of micropatterns because of its high efficiency and flexibility. However, speckle noise and energy fluctuations limit the quality of the printed structure. In this study, an improved complex‐amplitude modulation holographic femtosecond laser printing method for high‐quality micropattern fabrication is proposed. The holographic light field is divided into a signal area and a surrounding noise area. To improve laser uniformity, phase modulation is applied in the signal region to eliminate the speckle noise caused by unconstrained phase interference, and weighted amplitude modulation is introduced in the signal area to improve the calculation accuracy. To precisely control laser energy density, weighted energy efficiency modulation is introduced in the noise region to disperse the energy that exceeds the material damage threshold. Under the synergistic control of laser uniformity and energy density, high‐quality micro‐pattern structures are printed efficiently. A high‐quality millimeter‐sized multifocal zone plate with micron accuracy is fabricated with the splicing printing method, demonstrating the potential of micropattern processing and the fabrication of functional devices such as binary optics.

Enabling Uniform and Accurate Control of Cycling Pressure for All‐Solid‐State Batteries

AbstractAll‐solid‐state batteries are emerging as potential successors in energy storage technologies due to their increased safety, stemming from replacing organic liquid electrolytes in conventional Li‐ion batteries with less flammable solid‐state electrolytes. However, all‐solid‐state batteries require precise control over cycling pressure to maintain effective interfacial contacts between materials. Traditional uniaxial cell holders, often used in battery research, face challenges in accommodating electrode volume changes, providing uniform pressure distribution, and maintaining consistent pressure over time. This study introduces isostatic pouch cell holders utilizing air as pressurizing media to achieve uniform and accurately regulated cycling pressure. LiNi0.8Co0.1Mn0.1O2 | Li6PS5Cl | Si pouch cells are fabricated and tested under 1 to 5 MPa pressures, revealing improved electrochemical performance with higher cycling pressures, with 2 MPa as the minimum for optimal operation. A bilayer pouch cell with a theoretical capacity of 100 mAh, cycled with an isostatic pouch cell holder, demonstrated a first‐cycle Coulombic efficiency of 76.9% and a discharge capacity of 173.6 mAh g−1 (88.1 mAh), maintaining 83.6% capacity after 100 cycles. These findings underscore the effectiveness of isostatic pouch cell holders in enhancing the performance and practical application of all‐solid‐state batteries.

Synthesis of high-voltage spinel LiNi0.5Mn1.5O4 by Mn2O3 nanosheets for lithium-ion batteries with superior cycle life span

The development of high-voltage cobalt-free spinel LiNi0.5Mn1.5O4 (LNMO) by conventional solid-state methods is hampered by its rapid capacity decay due to the impurity phases, inhomogeneous particle size, and dissolution of transition metals. To realize large-scale production and application of LNMO, a two-step modified solid-state method with Mn2O3 nanosheets as a precursor is proposed here. The resulting material (P-LNMO) shows a reduced rock salt impurity phase and enhanced ionic transport through a more uniform control of particle size. As a result, the cycling stability of the disordered LNMO is remarkably improved, where LNMO half-cell capacity retention is 89.5 % at ambient temperature after 1000 cycles. What's more, the LNMO/Graphite full-cell is further assembled showing a discharge specific capacity of 110 mAh g−1 at 1C, and remains 97 % of its initial capacity after 100 cycles. The excellent electrochemical performance indicates that this modified solid-state approach brings a new avenue to the synthesis of LNMO for the upcoming generation of commercial lithium-ion batteries.