Efficient Suppression Research Articles

Experimental study on the dust control performance of rotating fog curtain under the perturbation of long-pressure and short-pumping ventilation

The dust source point in the coal-breaking operation prolonged activities generate substantial dust, diminished the air quality at the tunneling face. This study focuses on the pneumatic vortex fog curtain dust control system in the underground coal mine tunneling face. It explores the dust-trapping performance of this system under the disturbance of a long-pressure and short-suction auxiliary ventilation system. The results indicate that the respiratory dust captured by the fog curtain wall on the driver’s working side can be reduced from an average concentration of 135.5 mg/m3 to 2.5 mg/m3, and on the 15 m downwind side of the coal-cutting machine, it decreases from 70.2 mg/m3 to 2.5 mg/m3. Under the disturbance of the long-pressure and short-suction ventilation system, as the wind speed increases, the rotating fog curtain gap expands, reducing the sealing performance. Without compromising the fog curtain conditions, this combined system achieves efficient dust suppression, significantly improving the working environment at the tunneling face.

Integrating pyriproxyfen into the incompatible insect technique enhances mosquito population suppression efficiency and eliminates the risk of population replacement.

The incompatible insect technique (IIT) has been used for Aedes mosquito population suppression to curb the transmission of dengue. However, its wide application is limited owing to the low output of male mosquitoes and the risk of population replacement from the release of fertile Wolbachia-infected females. This study aims to improve IIT efficiency for broader adoption. We assessed the impact of 10% pyriproxyfen (PPF) sticky powder exposure on Wolbachia (from Culex molestus)-transinfected Aedes albopictus Guangzhou line (GUA line) (GC) mosquitoes. We found that the exposure caused chronic toxicity in adult mosquitoes without affecting the cytoplasmic incompatibility (CI)-inducing capability of males. The PPF-contaminated GC females exhibited significant sterilization and the ability to disseminate lethal doses of PPF to breeding sites. Subsequently, we conducted a field trial combining PPF with IIT aiming to suppress the Ae. albopictus population. This combined approach, termed boosted IIT (BIIT), showed a notable enhancement in population suppression efficiency. The improved efficacy of BIIT was attributed to the dispersion of PPF particles in the field via the released PPF-contaminated male mosquitoes. During the BIIT field trial, no Wolbachia wPip-positive Ae. albopictus larvae were detected, indicating the effective elimination of the risk of Wolbachia-induced population replacement. Additionally, the field trial of BIIT against Ae. albopictus resulted in the suppression of the nontarget mosquito species Culex quinquefasciatus. Our results highlight the remarkable efficiency and feasibility of combining IIT with PPF in suppressing mosquito populations, facilitating the widespread implementation of IIT-based management of mosquito-borne diseases. © 2024 Society of Chemical Industry.

Enhancement of calcium alginate and urea in gel-modified dry water inhibition of methane-air explosion

Methane has a wide range of applications in several industries. However, it also exhibits flammable and explosive properties, which pose a potential hazard. This study used calcium alginate to make ordinary dry water powder have a stable network gel structure, and urea was added to enhance further dry water powder’s chemical inhibition. A visual test system verified the explosion suppression effect of gel-modified dry water powder on the methane-air explosion. The results show that the optimal parameters for Ordinary dry water preparation were as follows: mass ratio of SiO2 to H2O = 9:100, stirring speed = 5000 r/min, stirring time = 240 s. The powder concentration for the best explosion suppression effect is 0.52 g/L. 10 mass% Urea-modified dry water, which achieves high explosion suppression efficiency in the methane-air explosion system by cooling and endothermic suppressing the explosion reaction. The spatial distribution of Calcium alginate gel urea modified dry water hinders the propagation of the flame. Urea continuously produces nitride at different temperatures, and nitride competes for O2 and OH· Free radicals, thus destroying the methane-air explosion chain reaction. Calcium alginate gel urea (10 mass%) modified dry water of 0.52 g/L has the best explosion suppression efficiency, which reduces the flame propagation velocity of methane-air explosion system by 42.48 %, the suppression efficiency of flame temperature reaches 40 %, and the suppression effect on explosion relief pressure reaches 16 %. Calcium alginate gel urea modified dry water, a new explosion suppression material, significantly improve the explosion suppression effect of methane-air explosions, which can not only improve the industrial safety of methane-containing processes, extend equipment life, and reduce production costs but also help improve environmental protection and resource utilization efficiency by inhibiting methane explosions. This study helps to promote the development of gas explosion suppression materials and has practical significance for safe energy utilization and industrial methane applications.

High Azimuthal Mode Selectivity of a Cavity with Mode-Joining Corrugations for High-Harmonic Gyrotrons

Mode-joining longitudinal corrugations are studied as a means of high azimuthal mode selectivity for cavities of high-harmonic terahertz gyrotrons. Their number dictates the choice of the jointed operating mode, which has a form of strongly coupled co- and counter-rotating azimuthal harmonics. It is found that the distinctive feature of this mode is a weak dependence of eigenvalue and ohmic losses on corrugation size. First, this favors the use of mode-joining corrugations with variable depth for efficient suppression of all competing modes by both diffractive and ohmic losses in the gyrotron cavity. Second, this provides a good robustness of gyrotron performance against manufacturing errors in the size of corrugations and only a minor conversion of the operating mode to spurious modes at junctions of the corrugated cavity with smooth-walled waveguides. The beneficial properties of mode-joining corrugations are demonstrated by a cavity design for a gyrotron operated in the second-harmonic TE±9,4 and third-harmonic TE±18,4 modes at 398 GHz and 593 GHz, respectively.

Carboxylesterase-activatable multi-in-one nanoplatform for near-infrared fluorescence imaging guided chemo/photodynamic/sonodynamic therapy toward cervical cancer

Traditional tumor treatment faces great challenge owning to inherent drawbacks. Activatable prodrugs with multi-modality therapeutic capacity are highly desired. In this consideration, a responsiveness-released multi-in-one nanoplatform, PLGA-PEG@HC, toward cervical cancer therapy was innovatively developed. Among the nanoplatform, HC was constructed by incorporating chlorambucil, a classic chemotherapy drug into a near-infrared photo- and sono-sensitizer, HCH via ester linker, which can be specifically hydrolyzed by carboxylesterase (CES). HC is scarcely fluorescent and toxic due to the caging of HCH and chlorambucil, thus achieving low background signal and minimal side effects. However, once selectively hydrolyzed by tumor enriched CES, ester bond will be broken. Consequently, HCH and chlorambucil are released so as to achieve near-infrared fluorescence imaging and synergistic photodynamic/sonodynamic/chemo therapy. PLGA-PEG packaging ensures the biocompatibility of HC. The as-obtained nanoplatform, with diameter of 97 nm, achieves tumor targeting capacity via EPR. In vitro and in vivo applications have demonstrated that PLGA-PEG@HC can accumulate in tumor tissues, exhibit CES-activatable near-infrared fluorescence imaging and efficient tumor suppression capacity. Compared with the reported combinational therapy materials which are complex in compositions, PLGA-PEG@HC is simple in formulation but demonstrates near-infrared fluorescence traced and considerable therapy efficacy toward tumors, which may accelerate the clinical translation.

Efficient suppression of premature termination codons with alanine by engineered chimeric pyrrolysine tRNAs.

Mutations that introduce premature termination codons (PTCs) within protein-coding genes are associated with incurable and severe genetic diseases. Many PTC-associated disorders are life-threatening and have no approved medical treatment options. Suppressor transfer RNAs (sup-tRNAs) with the capacity to translate PTCs represent a promising therapeutic strategy to treat these conditions; however, developing novel sup-tRNAs with high efficiency and specificity often requires extensive engineering and screening. Moreover, these efforts are not always successful at producing more efficient sup-tRNAs. Here we show that a pyrrolysine (Pyl) tRNA (tRNAPyl), which naturally translates the UAG stop codon, offers a favorable scaffold for developing sup-tRNAs that restore protein synthesis from PTC-containing genes. We created a series of rationally designed Pyl tRNAScaffold Suppressor-tRNAs (PASS-tRNAs) that are substrates of bacterial and human alanyl-tRNA synthetase. Using a PTC-containing fluorescent reporter gene, PASS-tRNAs restore protein synthesis to wild-type levels in bacterial cells. In human cells, PASS-tRNAs display robust and consistent PTC suppression in multiple reporter genes, including pathogenic mutations in the tumor suppressor gene BRCA1 associated with breast and ovarian cancer. Moreover, PTC suppression occurred with high codon specificity and no observed cellular dysregulation. Collectively, these results unveil a new class of sup-tRNAs with encouraging potential for tRNA-based therapeutic applications.

A Nanocluster Colloidal Electrolyte Enables Highly Stable and Reversible Zinc Anodes.

Aqueous zinc-ion batteries represent a favorable technology for stationary energy storage systems owing to their safety, reliability, and cost-effectiveness. However, Zn anodes suffer uncontrollable dendrite formation and harmful side reactions that lead to a short lifespan. Herein, we demonstrate a nanocluster colloidal electrolyte strategy for stabilizing the zinc anodes. A copper nanocluster (CuNC) is screened out to validate the efficient suppression of messy dendrites and side reactions. A CuNC could resurface a zincophilic and protective interlayer for interfacially steering uniform Zn stripping/plating and mitigating corrosion/hydrogen evolution reactions. Impressively, the colloidal electrolyte enables zinc anodes to show a high Coulombic efficiency of 99.8% over 2100 cycles and extended lifespans of 2200 and 1300 h under 0.5 and 5 mA cm-2, respectively. A full cell based on the modified electrolyte exhibits significantly improved cycling durability for more than 15 000 cycles. This work will aid in the design of nanocluser colloidal electrolytes with respect to stable zinc chemistry and beyond.

Different metal-doped NiO nanoparticles for sunlight-mediated degradation of low-density polyethylene microplastic films.

Due to the widespread use and incorrect handling of plastics, we need to find a practical and effective way to eliminate plastic waste from the environment. Different metal-doped nickel oxide (DMD-NiO) nanoparticles (NPs) were synthesized using a sol-gel technique and were used to degrade low-density polyethylene (LDPE) microplastic (MP) films when exposed to sunlight. The optical and structural properties of sol-gel method synthesized materials were investigated using a variety of characterization methods (Fourier transform infrared (FT-IR), UV-vis diffuse reflectance spectroscopy (UV-vis DRS), X-ray diffractometer (XRD) analysis, X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HR-TEM), scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis, and thermogravimetric analysis (TGA). Degradation study results suggest that the photocatalytic activity of DMD-NiO-LDPE nanocomposites (NCs) films was greater than that of pure LDPE and undoped NiO-LDPE films. Because of their increased optical absorption and efficient suppression of photo-produced charge carriers' recombination, the DMD-NiO NPs showed higher photocatalytic degradation of LDPE films. Thus, LDPE films with 2% wt Fe-NiO (iron-doped nickel oxide) nanomaterials showed a degradation of around 38.16% among DMD-NiO-LDPE NCs films under visible light over a short period of 30 days (240 h). The formation of carbonyl groups in the degradation product of LDPE was confirmed by Fourier transform infrared (FT-IR) analysis. When compared to the original LDPE film, the Fe-NiO-LDPE NCs films showed a significant decrease in crystallinity and carbonyl indexes, as much as 8.4% lower. The current project proposes the development of eco-friendly photocatalysts using a sol-gel technique for combating MP pollution in the environment.

A stage structured model for mosquito suppression with immigration.

The incompatible insect technique based on Wolbachia is a promising alternative to control mosquito-borne diseases, such as dengue fever, malaria, and Zika, which drives wild female mosquitoes sterility through a mechanism cytoplasmic incompatibility. A successful control program should be able to withstand the perturbation induced by the immigration of fertilized females from surrounding uncontrolled areas. In this paper, we formulated a system of delay differential equations, including larval and adult stages, interfered by Wolbachia-infected males. We classified the release number of infected males and immigration number of fertile females, to ensure that the system displays globally asymptotically stable or bistable dynamics. The immigration of fertile females hinders the maximum possible suppression efficiency so that the wild adults cannot be reduced to a level below $ A^*_\infty $. We identified the permitted most migration number to reduce the wild adults to a target level. To reduce up to $ 90\% $ of wild adults in the peak season within two months, an economically viable strategy is to reduce the immigration number of wild females less than $ 0.21\% $ of the carrying capacity of adults in the control area.

A composite structure device: vibration control and energy harvesting of tool system in aviation thin-walled parts milling process

Abstract The intense vibration generated by the high-speed milling cutter in the processing process not only seriously affects the surface roughness but also may damage important components of the machine tool, resulting in significant economic losses. Therefore, a composite structure of piezoelectric energy-collector (PEC) and nonlinear energy sink (NES) is innovatively constructed by combining theoretical research and numerical analysis to achieve more efficient vibration suppression and energy recovery in milling. Using the Hamilton principle, the electromechanical model of the composite structure is developed. Then, based on the Galerkin truncation to discretized displacement functions, we solve the amplitude-frequency response of the tool structure by using the harmonic balance method. The validity analysis of the proposed method can be verified by rigorous comparison with the results of the Runge-Kutta method. A novel NES-PEC composite structure presented in this work shows excellent vibration suppression capability in the milling process. More importantly, the structure also enables self-powered sensing of the tool system, significantly reducing dependence on external power sources. This innovative design substantially improves the stability and reliability of milling processes and opens up new ways to optimize the energy efficiency of tool systems. In summary, this paper’s modeling and solving methods, vibration reduction techniques, and energy harvesting strategies have laid a solid foundation for applying a high-speed milling cutter system. More relevant literature on applying vibration suppression and energy harvesting devices in milling must be reviewed. This paper fills in the research gap and provides a valuable reference for future tool systems design and optimization.

Searching Across Realities: Investigating ERPs and Eye-Tracking Correlates of Visual Search in Mixed Reality.

Mixed Reality allows us to integrate virtual and physical content into users' environments seamlessly. Yet, how this fusion affects perceptual and cognitive resources and our ability to find virtual or physical objects remains uncertain. Displaying virtual and physical information simultaneously might lead to divided attention and increased visual complexity, impacting users' visual processing, performance, and workload. In a visual search task, we asked participants to locate virtual and physical objects in Augmented Reality and Augmented Virtuality to understand the effects on performance. We evaluated search efficiency and attention allocation for virtual and physical objects using event-related potentials, fixation and saccade metrics, and behavioral measures. We found that users were more efficient in identifying objects in Augmented Virtuality, while virtual objects gained saliency in Augmented Virtuality. This suggests that visual fidelity might increase the perceptual load of the scene. Reduced amplitude in distractor positivity ERP, and fixation patterns supported improved distractor suppression and search efficiency in Augmented Virtuality. We discuss design implications for mixed reality adaptive systems based on physiological inputs for interaction.

Fire suppression efficiency improvement and comparative analysis of flake black lead composite

Fire suppression efficiency improvement and comparative analysis of flake black lead composite

Flexible speckle-free polymer-stabilized liquid crystal screen for laser projection

Despite considerable effort and progress, accomplishing speckle-free laser displays remain challenging, particularly in flexible displays. In this paper, we propose a novel and easy-to-implement method for developing a flexible polymer-stabilized liquid crystal (PSLC) screen. A uniformly alignment layer was achieved on polyethylene terephthalate substrates using a low-temperature curing system, and polystyrene (PS) microspheres are spin-coated to enhance the mechanical stability. The dynamic scattering of the PSLC effectively reduces laser speckle, leading to improved image clarity. When applied to a laser projection system, the developed flexible PSLC screen exhibits good image quality, low light-intensity loss, and a speckle suppression efficiency of 77.9%. Furthermore, it exhibits excellent optical performance, mechanical stability, and size adaptability, which are suitable for applications in flexible, transparent, and augmented/virtual reality displays; and other optical imaging scenarios.

Staggered distribution structure Cu-Mn catalysts for mitigating smoke and gas toxicity in combustion: Unravelling mechanistic insight through operando studies

The integration of flame retardancy and environmental friendliness can be achieved by designing cost-effective, stable, and efficient catalysts to reduce smoke and toxicity during the combustion of polymeric materials. This work reports the development of non-precious metal catalysts for thermoplastic polyurethanes (TPU), which exhibit a significant reduction in smoke and gases toxicity while providing flame retardancy. The use of MgB2 as a support enables the in-situ growth of highly efficient Cu-Mn based catalysts, resulting in a remarkable 51.5 % decrease in total smoke release and a 49.1 % reduction in peak rate of CO generation of TPU according to cone calorimeter test results. Furthermore, Cu-Mn/MgB2 demonstrates an impressive 83.1 % reduction in total CO production rate during the steady-state tube furnace test. Additionally, density functional theory is employed to analyze the binding energy between catalysts and TPU as well as the adsorption energy of gases. This elucidates the rational reaction mechanism behind the catalyst and smoke inhibiting process. By combining transition metal oxide catalyzed CO oxidation reaction with polymeric material combustion, this study presents a promising approach for efficient smoke suppression with potential applications.

Learning the Universe: GalactISM Simulations of Resolved Star Formation and Galactic Outflows across Main-sequence and Quenched Galactic Environments

We present a suite of six high-resolution chemodynamical simulations of isolated galaxies, spanning observed disk-dominated environments on the star-forming main sequence, as well as quenched, bulge-dominated environments. We compare and contrast the physics driving star formation and stellar feedback among the galaxies, with a view to modeling these processes in cosmological simulations. We find that the mass loading of galactic outflows is coupled to the clustering of supernova explosions, which varies strongly with the rate of galactic rotation Ω = v circ/R via the Toomre length, leading to smoother gas disks in the bulge-dominated galaxies. This sets an equation of state in the star-forming gas that also varies strongly with Ω, so that the bulge-dominated galaxies have higher midplane densities, lower velocity dispersions, and higher molecular gas fractions than their main-sequence counterparts. The star formation rate in five out of six galaxies is independent of Ω and is consistent with regulation by the midplane gas pressure alone. In the sixth galaxy, which has the most centrally concentrated bulge and thus the highest Ω, we reproduce dynamical suppression of the star formation efficiency in agreement with observations. This produces a transition away from pressure-regulated star formation.

Advancing Multi‐Optical Performances in Lanthanide‐Doped Fluoride Core@Shell Nanoarchitectures by Minimizing Cation Intermixing

AbstractCore/shell structures are widely employed to enhance photoluminescence efficiency and manipulate excitation dynamics in lanthanide‐doped fluoride nanoparticles (NPs). However, prominent cation intermixing leads to significant deviations from the expected optical performances, presenting a formidable challenge in a deeper understanding of the chemical processes involved, as well as developing efficient suppression methods. Here, a reliable and facile multi‐optical reference strategy to reveal the integral cation intermixing processes is designed. This strategy analyzes the presence of Ce3+ ions in the core (or shell) and their influences on near‐infrared light‐triggered upconversion (UC), ultraviolet (UV)‐activated downshifting (DS), and X‐ray‐excited optical/persistent luminescence (XEOL/XEPL) of Tb3+ ions in the shell (or core). The results demonstrate that a thin surface layer of core NPs dissolves to reach dissolution equilibrium, which then distributes throughout the entire shell layer, rather than being confined to an interfacial region. It is further developed an improved technique to greatly inhibit cation intermixing by successive shell growth with excessive cation precursors, enabling superior multi‐optical performances, including UC, DS, XEOL/XEPL, and time‐dependent multicolor evolution. The findings significantly advance the development of lanthanide‐doped fluoride core/shell NPs with superior optical performances, broadening their potential applications in bio‐medicine, healthcare, industrial inspection, and optical information science.

Fluorescent Dye-Based Chiral Crystalline Organic Salt Networks for Circularly Polarized Luminescence.

A facile and general strategy is developed herein for the construction of circularly polarized luminescence (CPL) materials with simultaneously high fluorescence quantum efficiency (Φ) and large luminescence dissymmetry factor (glum). The self-assembly of fluorescent dye, disodium 4,4'-bis(2-sulfonatostyryl)biphenyl (CBS), with chiral diamines such as (R,R)/(S,S)-1,2-diaminocyclohexane (R/S-DACH) and R/S-1,2-diaminopropane (R/S-DAP), produces four chiral crystalline organic salt networks (COSNs). These as-synthesized organic salts emit strong blue-color CPL upon excitation, with both high Φ and glum values of up to 79% and 0.022. The well-defined molecular structures and arrangements of CBS are directly observed through single crystal X-ray analysis, offering crucial information regarding the origins of high-efficiency CPL performance. The chirality of amine is effectively transferred to CBS and further amplified to the supramolecular structure by multiple hydrogen bonding and π-π stacking interactions, giving rise to the large glum factors; meanwhile, the fixation and the ordered arrangement of CBS by these multiple interactions empower efficient suppression of molecular motions, facilitating strong fluorescence. This work can inspire the assembly of CPL organic materials with high Φ and glum via charge-assisted hydrogen bonds between fluorescent dyes and chiral inducers. It also offers important insight into the structural origins of supramolecular chirality and CPL performance.

Numerical Study of Vortex-Excited Vibration of Flexible Cylindrical Structures with Surface Bulge

This study conducted numerical simulations of three-dimensional vortex-induced vibrations (VIV) on cylindrical bodies with various surface protrusion coverage rates, systematically investigating the impact of coverage and protrusion height on the vibrational response of flexible cylinders. The fluid forces on the surface of the riser were resolved using the finite volume method, while the structural forces were solved with the finite element method. A strongly coupled approach was employed for iterative updates between the flow field and structural field data, achieving a bidirectional flow–structure coupling simulation of VIV in a marine environment. The study further explored the performance of surface protrusions in suppressing VIV and considered protrusion heights of 0.1 times the cylinder diameter (0.1D) under coverage rates (CR) of 0%, 10%, 20%, 30%, and 40%, as well as seven different protrusion heights of 0.05D, 0.1D, and 0.15D at a 20% coverage rate. The mechanism of VIV suppression by surface protrusions was identified as altering the separation point of the shear layer and the frequency of vortex shedding through the vortices formed between the surface protrusions. It was found that a 20% coverage rate with a protrusion height of 0.01D (CR20) effectively suppressed the VIV of the cylinder, showing the best performance in VIV suppression, with an efficiency of 30.04%. These results provide a theoretical basis for designing more efficient VIV suppression devices and contribute to enhancing the resistance of marine structures against vortex-induced vibrations.

Constructing electrochemically stable single crystal Ni-rich cathode material via modification with high valence metal oxides

Single crystal Ni-rich cathode materials (SCNCM) are a good supplement in the market of nickel-based materials due to their safety and excellent electrochemical performance. However, the challenges of cation mixing, phase change during charge/discharge, and low thermal stability remain unresolved in single crystal particles. To address these issues, SCNCM are rationally modified by incorporating transition metal (TM) oxides, and the influence of metal ions with different valence states on the electrochemical properties of SCNCM is methodically explored through experimental results and theoretical calculations. Enhanced structural stability is demonstrated in SCNCM after the modifications, and the degree of improvement in the matrix materials varies depending on the valence state of doped TM ions. The highest structural stability is found in WO3-modified SCNCM, due to the smaller effective ion radii, higher electro-negativity, stronger W–O bond, and efficient suppression of oxygen vacancy generation. As a result, WO3-modified SCNCM have outstanding cycle performance, with a capacity retention rate of 90.2% after 200 cycles. This study provides an insight into the design of advanced SCNCM with enhanced reversibility and cyclability.

“Borrow-force-attack-force” by multi-scale elastic metamaterial with nonlinear damping

The powerful energy carried by low-frequency vibration is often challenging to be effectively attenuated using traditional damping materials. If low-frequency vibration can be controlled through the energy carried by the excitation itself, the cost of achieving ultra-wide low-frequency vibration control would be significantly reduced. To this end, this paper constructs a multi-scale elastic metamaterial with nonlinear damping (MEMND) to achieve the efficient suppression of ultra-wide low-frequency vibration through its unique transmission characteristics and the effect of “borrow-force-attack-force” (leveraging the excitation to dampen vibration), which is amplified with increasing external excitation. Theoretical, simulation, and experimental results demonstrate that MEMND can achieve over 10 dB damping enhancement at the expense of losing a small amount of the bandgap effect. It exhibits high sensitivity to external excitation in the low-frequency region, offering a promising opportunity for “borrow-force-attack-force”. This work integrates a natural nonlinear damping element into elastic metamaterials and leverages the nonlinear action mechanism of external excitation, presenting a different approach for nonlinear metamaterial design with potential engineering applications.