Protection Performance Research Articles

Micro-Nano Dual-Scale Coatings Prepared by Suspension Precursor Plasma Spraying for Resisting Molten Silicate Deposit

Yb-doped Y2O3 stabilized ZrO2 (YbYSZ) coatings, developed through solution precursor plasma spraying (SPPS), are engineered to resist calcium–magnesium–alumino–silicate (CMAS) infiltration by leveraging their unique micro-nano structures. This provides superior anti-wetting properties, crucial for preventing CMAS penetration at high temperatures. The investigation focused on the structural and compositional changes in YbYSZ-SPPS coatings subjected to prolonged thermal exposure at 1300 °C. Results indicate that while the coatings undergo significant sintering, leading to densification and microstructural evolution, the elemental composition and phase stability remain largely intact after up to 8 h of heat treatment. Despite some reduction in CMAS resistance, the coatings maintained their overall protective performance, demonstrating the potential of SPPS coatings for long-term use in high-temperature environments where CMAS infiltration is a concern. These findings contribute to the development of more durable TBCs for advanced thermal protection applications.

Analysis of the Impact of Green Accounting Information Disclosure on Corporate Financial Performance

Green accounting information disclosure, as an emerging accounting practice, aims to promote corporate social responsibility by recording, reporting, and disclosing corporate actions and performance in environmental protection. This study explores the impact of green accounting information disclosure on corporate financial performance and its significance in modern corporate management. The study finds that green accounting information disclosure not only enhances a company s social image but also improves its financial performance in the long term.

Radiation Shielding Analysis of Multi-Component Glasses: Effects of Varying BaO, PbO2 and Gd2O3 Concentrations

This work investigates the impact of BaO, PbO2, and Gd2O3 on newly developed borate glasses’ radiation shielding characteristics. The transmission factor (TF) of the glasses is almost zero at the low energy of 0.0395 MeV, which indicates favorable low-energy photon shielding. The maximum TF is reported at 1.46 MeV for the free Gd2O3 glass sample, ranging from 0.89 (0.5 cm thickness) to 0.73 (1.5 cm thickness). Moreover, with more BaO, PbO2, and Gd2O3 content added to the glasses, the TF decreases, indicating an enhancement in the efficiency of the glasses’ radiation protection with the introduction of BaO, PbO2, and Gd2O3. There is a 4.309 to 5.068 g cm−3 increase in the glasses’ density, and, as a result, the mean free path decreases, suggesting improved performance for radiation protection with the adding of more BaO, PbO2, and Gd2O3 contents to the glasses. At 0.122 MeV, the free Gd2O3 glass’s half value layer value is 0.098 cm, while the tenth value layer is 0.325 cm.

Ball-Milling Enhanced UV Protection Performance of Ca2Fe-Sulisobenzone Layered Double Hydroxide Organic Clay.

Using a co-precipitation technique, the anionic form of sulisobenzone (benzophenone-4) sunscreen ingredient was incorporated into the interlayer space of CaFe-hydrocalumite for the first time. Using detailed post-synthetic millings of the photoprotective nanocomposite obtained, we aimed to study the mechanochemical effects on complex, hybridized layered double hydroxides (LDHs). Various physicochemical properties of the ground and the intact LDHs were compared by powder X-ray diffractometry, N2 adsorption-desorption, UV-Vis diffuse reflectance, infrared and Raman spectroscopy, scanning electron microscopy and thermogravimetric measurements. The data showed significant structural and morphological deformations, surface and textural changes and multifarious thermal behavior. The most interesting development was the change in the optical properties of organic LDHs; the milling significantly improved the UV light blocking ability, especially around 320 nm. Spectroscopic results verified that this could be explained by a modification in interaction between the LDH layers and the sulisobenzone anions, through modulated π-π conjugation and light absorption of benzene rings. In addition to the vibrating mill often used in the laboratory, the photoprotection reinforcement can also be induced by the drum mill grinding system commonly applied in industry.

The Threat Is Now: Choreography, Temporality, and the Active Shooter Drill

Abstract: This article explores how the police state choreographs active shooter drills as "performances of protection," or embodied actions framed around an anticipatory threat. During these scenarios, choreographic imperatives—or movement directives in response to specific cues—become tools for directing bodies through public space to preempt crisis. While these measures protect students, teachers, and administrators, they also reinforce the school-to-prison pipeline, targeting communities deemed dangerous by the police state. The article examines how such measures embody control, surveillance, and time as methods of discipline. It also analyzes what performances of protection reveal about the school-prison pipeline in the United States.

Composite fixed-length ordered features with index-of-max transformation for high-performing and secure palmprint template protection

Palmprint recognition has attracted considerable attention due to its advantages over other biometric modalities such as fingerprints, in that it is larger in area, richer in information and able to work at a distance. However, the issue of palmprint privacy and security (especially palmprint template protection) remains under-studied. Among the very few research works, most of them only use orientational features of the palmprint with transformation processing, yielding unsatisfactory recognition and protection performance. Thus, this research work proposes a palmprint feature extraction method for palmprint template protection that is fixed-length and ordered in nature, by fusing point features and orientational features. Firstly, dual orientations are extracted and encoded with more accuracy based on the modified finite Radon transform (MFRAT). Then, SURF feature points are extracted and converted to be fixed-length and ordered features. Finally, composite fixed-length ordered features that fuse up the dual orientations and SURF points are transformed using the irreversible transformation of index-of-max (IoM) to generate the revocable palmprint templates. Experiments show that the matching accuracy of the proposed method of fixed-length and ordered point features are superior to all other feature extraction methods on the PolyU and CASIA datasets. It is also demonstrated that the EERs before and after IoM transformation are better than all other representative template protection methods. A thorough security and privacy analysis including brute-force attack, false accept attack, birthday attack, attack via record multiplicity, irreversibility, unlinkability and revocability is also given, which proves that our proposed method has both high performance and security.

Proposing novel body-centered cubic lattice core sandwich panels as satellite structure

In the present paper, a comparative study on the load-bearing as well as shielding performance against hypervelocity impact of space debris of sandwich panels with body-centered cubic lattice core is performed numerically in order to evaluate their eligibility to be utilized as the satellite structure. To this end, four types of body-centered cubic lattice structures, with similar areal densities which are assumed to be made of 5A06 aluminum alloy, including BCC, BCCz (BCC reinforced in Z direction), and also BCCz-I and BCCz-II were considered. Whipple shield structure of same material and areal density was also investigated in order to justify the necessity of lattice structures application, especially in protection field. The present study simulates hypervelocity impact of a spherical projectile with 2 mm diameter, represented the space debris, collides with the structures at the velocity range of 2–6 km/s. Current numerical simulation process accuracy and efficiency were verified through comparing its obtained data based on simulating a problem had been investigated at a valid experimental study to the data proposed by the mentioned research. BCCz-II structure which is newly proposed at this study provided outstanding shielding and load-bearing capabilities in comparison to other structures. Furthermore, the detailed effects of projectile impact location and a middle structure placed plate on the protection performance were investigated and the mentioned items were found to have crucial impact on the structure shielding performance.

Evaluation of two household decontamination methods on protective mask materials and disinfection effects

Abstract In order to find affective disinfection methods for general public to reuse protective mask, which could address supply shortages in the period of epidemic, household ovens and household ultraviolet disinfection cabinets were used as decontamination tools, and the influence of decontamination process on the protective performance of masks including PFE and TIL, as well as virus (PV I and MHV) inactivation effect were completely evaluated. It was found that the dry heat and UVGI decontamination with household devices had a little impact on PFE or TIL of masks, which indicated that two process had little effect on mask material and face seal fit. The virus inactivation results showed that dry heat decontamination could effectively inactivate the virus on the masks, and UVGI decontamination could not completely inactivate the virus caused by the special shape of masks, which could be concluded that dry heat decontamination with household oven was a feasible method to reuse the mask, and UVGI decontamination was not recommended. This study had guiding significance for the decontamination and reuse of masks by the general public.

Penetration resistance of Al2O3 ceramic-ultra-high molecular weight polyethylene (UHMWPE) composite armor: Experimental and numerical investigations

To enhance the protective performance of ceramic composite armor, ballistic penetration experiments were conducted on Al2O3 ceramic-ultra-high molecular weight polyethylene (UHMWPE) composite armor with different thickness configurations. The damage and failure modes of hard projectiles and ceramic-fiber composite targets were analyzed. The recovered projectiles and ceramic fragments were sieved and weighed at multiple stages, revealing a positive correlation between the degree of fragmentation of the projectiles and ceramics and the overall ballistic resistance of the composite targets. Numerical simulations were performed using the LS-DYNA finite element software, and the simulation results showed high consistency with the experimental results, confirming the validity of the material parameters. The results indicate that the projectile heads primarily exhibited crushing and abrasive fragmentation. Larger projectile fragments mainly resulted from tensile and shear stress-induced failure. The failure modes of the composite targets included the formation of ceramic cones and radial cracks under high-velocity impacts. The UHMWPE laminated plates exhibited interlayer separation caused by tensile waves, permanent plastic deformation of the rear surface bulging, and perforation failure primarily due to shear forces.Through extended numerical simulations, while maintaining the same areal density and configuration of 9 mm Al2O3 ceramic + 12 mm UHMWPE laminated composite armor, the thickness configurations of the Al2O3 ceramic and UHMWPE laminated backplates were varied, and various thicknesses of UHMWPE laminates were simulated as the cover layer for the ceramic panels. The simulation results indicated that the composite armor configuration of 10 mm Al2O3 ceramic + 8 mm UHMWPE composite armor increased energy absorption by 13.48 %. When altering the cover layer thickness, a 4 mm UHMWPE + 9 mm Al2O3 + 8 mm UHMWPE composite armor demonstrated a 27.11 % improvement in energy absorption, showing a relatively significant enhancement.

Development of Methylene Bis-Benzotriazolyl Tetramethylbutylphenol-grafted lignin sub-microspheres loaded with TiO2 for sunscreen applications

Lignin serves as a promising Ultraviolet (UV) absorber within sunscreen industry. However, the commercial development of lignin-containing sunscreens faces challenges due to their low sun protection factor (SPF) and dark color in cosmetics industry. In this study, dual modifications on the chemical and physical structures of lignin were conducted to address these challenges. Initially, methylene bis-benzotriazolyl tetramethylbutylphenol (MBBT) was grafted onto alkali lignin (AL) through an atom transfer radical polymerization reaction, resulting in a polymer of AL-graft-MBBT3 (AL-g-MBBT3). The sunscreen prepared with 10 % AL-g-MBBT3 displays outstanding sun protection performance with a SPF of 42.93 and a light color with a color difference value (ΔE) of 45.6, in contrast to 10 % AL with a SPF of 4.74 and a ΔE value of 49.5. Subsequently, AL-g-MBBT3 was transformed into normal submicron spheres (AL-g-MBBT3 N) and TiO2-loading submicron spheres (AL-g-MBBT3/TiO2). The sun protection performances of 10 % AL-g-MBBT3 N@C and AL-g-MBBT3/TiO2@C sunscreens obviously surpass that of AL-g-MBBT3@C sunscreen, achieving SPFs of 60.38 and 66.20, respectively. Additionally, there is a considerable improvement in the color of these sunscreens, with ΔE values of 41.8 and 36.3, respectively. These results provide valuable insights into exploring lignin's high-value applications in sunscreen.

Support Vector Machine Framework for Detecting Ambiguous Contours of Space Debris Cloud

Operational spacecraft are prepared for collisions with space debris by installing protective walls (bumpers). A group of vaporized and liquefied microparticles generated by debris collisions is called a debris cloud. To evaluate the protective performance of bumpers, it is important to measure the spread velocity and angle of the debris cloud. However, debris cloud images exhibit ambiguous contours of debris clouds. Consequently, measurement errors in the spread velocity and spread angles occur because of the observer’s subjectivity. Commonly used derivative-based methods can detect steep contours; however, they cannot detect ambiguous contours such as those of debris clouds. In this study, a method for uniquely detecting the ambiguous contours of a debris cloud based on supervised machine learning and a continuous wavelet transform (CWT) is proposed. Feature points that indicate candidate points of the debris cloud contour are extracted using a method based on CWT. Four types of specific features for debris cloud contours were assigned to the feature points. Supervised machine learning using a support vector machine can detect the debris cloud contours. The proposed method enables the evaluation of the ambiguous contours of a debris cloud and the protection performance of a bumper without observer subjectivity.

Combustion flow field and thermal protection performance of a liquid oxygen/kerosene engine with pintle injectors

A pintle injector is a convenient method for adjusting propellant combustion and has received extensive attention in recent years. However, few studies have examined the effects of the injection direction and momentum ratio (ratio of liquid oxygen momentum to kerosene momentum) on the flow field, temperature field, and dual-belt liquid film cooling effect in the combustion chamber. This study verified a new computational fluid dynamics (CFD) engine combustion model based on a pintle injector through a hot-test experiment. A simulation was conducted using this model. With different injection directions, when the momentum ratio was increased, the trends in the combustion efficiency and chamber pressure growth were entirely opposite. For the axial kerosene and radial liquid oxygen injection direction of liquid film cooling, when the momentum ratio was 0.73–0.9, the proportion of the first ring belt liquid film flow was selected as 5–10 %, and the second ring belt liquid film flow proportion was selected as 5–7%. When the momentum ratio was less than 0.73, the liquid film flow proportions for both the first and second ring belts were selected as 5 %. When the total liquid film flow proportion was 10 %, the chamber pressure decreased by 0.2–0.3 MPa, and the combustion efficiency decreased by 8–10 %. This numerical study provides guidance for studying the combustion characteristics and cooling performance of pintle-type rocket combustion chambers.

Thermal Protection Performance Evaluation Based on Structural Composition Changes of the Intermediate-Layer Fabric in Thermal Protective Clothing

This study is a follow-up to ‘Research on the Development of Fabrics for Industrial and Firefighting Protective Clothing and Comparison of Flame Retardant Performance,’ focusing on the thermal protection performance of clothing designed to protect the human body from high temperatures and heat in industrial settings and fire scenarios. In this study, additional thermal protection performance tests were conducted to provide a more comprehensive analysis. Aside from the flame-retardant performance evaluation conducted according to ISO 15025 on 12 base fabrics with different yarn compositions, the following thermal performance studies were carried out: radiant heat protection (ISO 9151), convective heat protection (ISO 6942), and combined radiant and convective heat protection (ISO 17492). The heat-transfer index of the intermediate layer, which plays a crucial role in the thermal protection performance of thermal clothing, was also assessed. The results indicated that although most of the 12 base fabrics offered a certain level of thermal protection, some of them melted and failed to provide adequate thermal protection.

Corrosion protection performance of stretched graphene-modified cold-sprayed zinc coating for steel rebar

The cold-sprayed zinc technology exhibits unique advantages in the field of metal corrosion prevention due to its environmental friendliness and convenient construction. However, compared to hot-dip galvanizing, there is still a necessity to improve its corrosion resistance. Graphene as a filler material, effectively strengthens the anticorrosive properties of the coating. Nevertheless, the resistance of graphene-modified cold-sprayed zinc coating to chloride ion induced metal corrosion remains unknown. In this study, cold-sprayed zinc coating and graphene-modified zinc coating were employed to steel rebar that was subjected to different levels of tensile stress. The passivation and de-passivation process of the stretched zinc-coated rebar in the simulated concrete pore solution were investigated with electrochemical tests and microscopic analyses. The research findings reveal that compared with ordinary cold-sprayed zinc coating, graphene-modified coating can significantly improve the coating resistance and reduce the corrosion rate of rebar under different levels of tensile stress attributed to the high surface area of graphene. However, due to the discontinuity between zinc powders induced by graphene, a complete passivation film cannot form on the surface of graphene-modified zinc coating, which resulted in a lower resistance against chloride ion induced de-passivation. This study indicates that graphene-modified cold-sprayed zinc-coating is not fit for marine environment.

Biomimetic design and impact simulation of Al2O3/Al composite armor based on armadillo shell

The advancement of lightweight protective armors holds critical importance for enhancing the maneuverability and combat capabilities of helicopters. Leveraging insights from bionics, it provides a new idea for high-performance armor design. In this study, a new type of composite armor was designed by referring to the structural characteristics of hard phase-protection, soft phase-buffering of unitization armadillo shell. Through the numerical study, the anti-ballistic performance of armor with varying thickness ratios of the dense ceramic layer to the interpenetrating layer is obtained, and the influence of different structures of armor on the anti-ballistic performance is analyzed. The results show that compared with the traditional laminated composite armor, the Al2O3/Al biomimetic composite armor not only improves the separation phenomenon caused by wave impedance mismatch, but also greatly improves the speed drop in resisting high-speed and penetrating bullets. When the thickness ratio is 2:1, the armor has higher ballistic protection performance.

Development of a fuzzy logic-based model for assessing the reliability of relay protection systems

This article presents a reliability assessment model for relay protection devices using fuzzy logic. It introduces an algorithm for simulating these devices, employing the Mamdani model with an "if-then" rule base. Inputs include the percentage of correct operation and the frequency of correct and incorrect operations. Implemented in Matlab with 21 rules, the fuzzy logic model uses triangular membership functions for input and output variables, with defuzzification via the center of gravity method. The model was tested using statistical data from SIEMENS SIPROTEC terminals, specifically distance protection and differential protection devices for transformers and autotransformers. The assessment considers operation frequencies for 1 to 3 devices, combining statistical and simulation data for a comprehensive analysis. Results show that including operation frequencies improves evaluation accuracy. The proposed model not only assesses current reliability but also predicts future behavior, aiding in the planning and optimization of relay protection systems. This model is valuable for professionals in generating companies, grid organizations, and operational dispatch control entities, helping them analyze relay protection performance and develop strategies to ensure reliable operation. The research focuses on the reliability of relay protection devices in power systems, addressing the need for a more accurate and comprehensive evaluation method. Traditional methods may not fully account for the complexities in modern microprocessor-based protections. This study aims to enhance reliability assessments through a model that integrates statistical data and simulation techniques, ultimately supporting better planning and optimization of relay protection systems

Performance analysis of fire protective clothing: a review

Firefighters in such serious environments (i.e., hazardous flames and radiant heat, high air temperatures, hot chemicals and liquids) must wear fire protective clothing during fire extinguishing and rescue operations. Many studies in the field of fire protective clothing have been conducted to evaluate the protective, mechanical and comfort performance of fire protective clothing. A comprehensive review of the literature has been undertaken to provide a better understanding of single-layer and multilayer fire protective clothing with protective, mechanical and comfort performance. Factors affecting the durability of protective clothing in the light of their expected retirement age and a number of significant standards for laboratory and manikin testing are discussed. The comfort of wearing clothing is another aspect that needs special consideration when designing a multilayered fire protective suit. A number of emerging technologies have been outlined to address the various challenges of the present day.

Long-lasting anti-corrosion direct-to-metal polyurethane NP-GLIDE coatings based on the coordination effect and dual cross-linking of polyphenol

Aluminum and its alloys have been widely used in our lives. However, Aluminum and its alloys is prone to corrosion, especially in harsh environment. In recent years, hydrophobic coatings were used in the corrosion protection of metal. But, the low surface tension of resins made them have a worse wettability on metal which had high surface tension, resulting in a worse adhesion of these coatings. Herein, we developed a long-lasting anti-corrosion direct-to-metal polyurethane NP-Glide coating based on the coordination effect of polyphenol and dual cross-linking. In comparative evaluation, the corrosion protection and anti-contamination performances of direct-to-metal polyurethane NP-Glide coating are significantly improved by the introduction of functional monomer dopamine methacrylamide (DMA) and TEMAc-8. The PU coatings with 10 wt% TEMAc-8 possesses high impedance value (|Z|0.01Hz > 109 Ω•cm2) after 40 days of immersion in 3.5 wt% NaCl solution, exhibiting a great pull-off adhesion both in dry and wet coating, and a long-term anti-corrosion performance for aluminum alloy protection.

Study on the control of transverse cracks at the corners of large square billets for continuous casting of marine 945 hypo-peritectic micro-alloyed steel

Hypo-peritectic micro-alloyed steel has strong crack sensitivity, and marine 945 steel, as a kind of sub-encapsulated crystalline micro-alloyed steel, has frequent corner cracks during production, which seriously affects the production rhythm and reduces the product quality. Through the study of the morphology and composition of the matrix near the crack, the study and analysis of the high-temperature mechanical properties of the steel itself, and combined with the actual production situation, the causes of the corner cracks were clarified and the process optimisation was carried out accordingly. The results of the study show that the generation of corner cracks is due to the improper deoxidation process, uneven heat transfer inside the crystallizer and inappropriate cooling water parameters in the steelmaking process. By changing the deoxygenation method, crystallizer protective slag performance, crystallizer cooling water volume, water volume in the second cooling zone and other measures, the occurrence of billet corner cracks was effectively reduced, and the frequency of billet corner cracks was reduced from 6.3 to 2/m.

Discrepancy evaluation in mechanics and corrosion resistance of reactive plasma sprayed TiN coatings fabricated under different heat treatment

Ceramic coatings have positive feedback to annealing treatment, but improper annealing treatment can also bring disastrous consequences. In this article, a thick TiN coating without a bonding layer was prepared by reactive plasma spraying technology and then subjected to heat treatment at three different temperatures in atmospheric and argon atmospheres. By exploring the hardness, modulus, and corrosion resistance of the coatings, combined with analysis of microstructure, phase composition, and interatomic bonding conditions, it was found that the TiN coating exhibited the lowest porosity after atmospheric heat treated at 500 °C. Meanwhile, it also showed the highest hardness, modulus, and optimal corrosion resistance. After heat treated at 650 °C in the atmosphere, the protective performance of the coating was decreased, but it was still far superior to the as-sprayed coating. The coating after heat treated in the argon atmosphere did not achieve ideal performance. The coating heat treated at 650 °C even exhibited inferior comprehensive performance to the as-sprayed coating. Therefore, it was summarized that the atmospheric environments and the temperature above the phase transition temperature were suitable for obtaining the optimal TiN coating.