ABSTRACT The pyrotechnic delay plays a critical role in providing a time interval between two successive explosive events in the explosive train. The delay composition is filled into a metal tube in the form of compressed powder, consisting of fuel, oxidizer, and binder. The Inverse burn rate (IBR, s/cm) of the delay composition is a determining factor that plays a vital role in providing delay time within a particular column length of the delay element. In the present study, an experimental investigation was conducted on the inverse burn rate of a B/BaCrO4/NC-based binary delay system by varying the stoichiometry (10/90), where boron serves as the fuel, barium chromate as the oxidizer, and nitrocellulose (NC) acts as the binder. The effect of stoichiometry on density, heat of reaction, particle size, crystallite size, and thermal conductivity of the composition, as well as the impact of these parameters on the inverse burn rate (IBR) and delay time of the binary delay composition, has been studied. The method for controlling all these parameters has been discussed. The effect of hardware and temperature conditioning on delay time was studied experimentally. Results revealed that, as the percentage of boron decreases and barium chromate increases, the heat of reaction and thermal conductivity of the composition decrease; the density, crystallite size and particle size of the composition increase. It is evident that these parameters significantly affect IBR and delay time. The B/BaCrO4/NC binary delay shows IBR ranging from (0.22–1.59 s/cm) with reliable burning and smooth propagation at all temperature conditions in different hardware. The composition supported combustion, having up to 3% boron and more than 10% boron, it becomes a flash composition. The B/BaCrO4/NC binary delay composition burns slower and produces more delay time in brass hardware as compared to aluminum hardware. The thermal conductivity of the hardware plays a critical role in achieving a tunable delay time within the specified column length of the delay tube. This research work is useful to tailor the IBR and to improve the consistency in the delay time of pyro devices.

Enhancing vibration damping through controlled porosity in PBF-LB/M-manufactured parts: an experimental investigation

A multiscale modeling approach is proposed to investigate the mechanical properties of carbon fiber/silicon carbide (C/SiC) composites fabricated by chemical vapor infiltration (CVI) process. First, reactive molecular dynamics simulations are conducted to estimate the mechanical properties of the SiC matrix fabricated via CVI. Subsequently, a two-level micromechanics-based homogenization is developed to account for the effects of various constituents (e.g., porosity and carbon fiber) on the mechanical properties of the C/SiC composites. A series of numerical parametric studies is performed to examine the influence of the model parameters on the mechanical properties of the C/SiC composites. In addition, experimental investigations, including tensile tests and scanning electron microscopy, are conducted to validate the proposed modeling approach. The results indicate that the proposed modeling approach provides predictions that are in good agreement with the experimental results, thereby demonstrating the effectiveness of the proposed modeling scheme.

To investigate the hypersonic boundary layer transition over complex three-dimensional configurations, this study conducted an experiment using infrared thermography, Rayleigh scattering visualization, and high-frequency pressure sensors in a Mach 6 Ludwieg wind tunnel. The infrared results indicate that increasing the Reynolds number promotes boundary layer transition on the model surface. Spectral analysis reveals a high-frequency peak centered at 250 kHz on the finless side of the windward surface. Comprehensive analysis indicates this represents high-frequency secondary instability triggered by the traveling crossflow mode in its nonlinear phase. On the finless side of the leeward surface, a typical Mack second-mode high-frequency instability amplification process is observed within the 140–280 kHz frequency band. Additionally, the spectrum results for the fin–cone junction became more complex. On the windward side, the primary energy concentration in the junction zone is observed between 80 and 200 kHz, with calculated wave packet velocities higher than those on the finless side. Wavelet analysis reveals that low-frequency modes are amplified first and gradually excite high-frequency components, with significant modal coupling appearing in the high-frequency region of the bicoherence. The leeward fin–cone junction exhibits dual-band characteristics at 60–120 kHz and 180–260 kHz, demonstrating stronger intermodal interactions. Both the windward and leeward surfaces of the fin show low-frequency transverse flow-like modes around 70–180 kHz. The spectral results for the windward and leeward sides are largely consistent, with only slight differences in amplitude levels and saturation positions.

Experimental and Numerical Investigation of Unsteady Flow in Centripetal Turbine Cavity

Solar energy-driven hydrogen peroxide (H2O2) synthesis from atmospheric oxygen and water represents a sustainable and highly promising avenue for the production of this essential chemical. Covalent organic frameworks (COFs) offer a molecular platform for the direct conversion of solar energy to H2O2, however, they are persistently plagued by the recombination of photogenerated charge carriers, a phenomenon induced by σ-bond rotation under light irradiation, which typically leads to sluggish conversion kinetics and suboptimal efficiency. We herein present a molecular engineering strategy involving the construction of noncovalent trans rings (Nc-TRs) within COFs. This approach entails the precise introduction of noncovalent interactions between donor and acceptor moieties, thereby constraining the free rotation of σ bonds and substantially suppressing the recombination of photogenerated charge carriers. Experimental and theoretical investigations demonstrate that the incorporation of Nc-TR within TAPT-DHBD COFs reduces the molecular dihedral angle from 37.33° to 0°, thereby optimizing molecular coplanarity and prolonging the photogenerated charge carrier lifetime by 820% compared to TAPT-TPD COFs devoid of Nc-TRs. Our findings further reveal that TAPT-DHBD COFs exhibit 5.0-fold and 3.6-fold enhancements in H2O2 photocatalytic conversion kinetics and solar-to-chemical conversion (SCC) efficiency, respectively, relative to TAPT-TPD COFs. We further demonstrate that H2O2 solutions generated in the flow-type photocatalytic system under solar irradiation exhibit a record-high antibacterial efficacy of 107 cfu s-1, and achieve a 100% wound healing rate within 7 d, markedly outperforming commercial physiological saline.

The phosphorus (P) cycle links the co-evolution of the biosphere and geosphere over geologic time. Modern P availability is primarily controlled by mineral adsorption, but how such processes might have operated under early Earth's anoxic conditions remains unclear. Here, we combine experimental and theoretical investigations of P adsorption onto common phyllosilicates to evaluate their role in the early P cycle. We show that the P adsorption would have been significantly enhanced in early ferruginous waters, primarily through dissolved Fe(II) bridging between orthophosphate and mineral surfaces. Such enhanced P adsorption onto phyllosilicates could have facilitated the riverine transport of bioavailable P during Archean anoxic continental weathering, yet also promoted its rapid burial in shallow marine settings. Moreover, phyllosilicate adsorption would have limited dissolved P release during seafloor weathering in the Archean and Proterozoic oceans. These processes collectively could have limited dissolved P availability for the origin and evolution of early life.

A dedicated experimental rig is presented for a half-journal bearing operating under highly loaded, well-controlled hydrodynamic lubrication conditions relevant to turbomachinery. The apparatus combines pressure measurements in the film, distributed temperature measurements in the shaft and bush, and ultrasonic film-thickness measurements that map the circumferential film-thickness profile across the lubrication region. Experiments are reported for normal loads of 5–20 kN and shaft speeds of 1000–4000 rpm with controlled oil supply conditions. The measured pressure and temperature trends are consistent with established hydrodynamic lubrication behaviour. The film thickness measurements confirm full-film operation across the tested operating envelope, while indicating increased uncertainty in regions affected by cavitation. A correlation for the temperature rise due to viscous heating is proposed as a compact representation of the data. The rig design and accompanying measurements provide a benchmark-quality data set intended for validation and development of thermal elasto-hydrodynamic lubrication (TEHL)/computational fluid dynamics (CFD) models under high load and speed conditions.

The development of effective water-injection systems is essential for mitigating acoustic loading from high-thrust rocket engines during launch. To address this challenge, Beihang University established the Liquid Propellant Engine Acoustic Rig (LPEAR), an experimental facility capable of generating supersonic jet flows up to Mach 3 and stagnation temperatures of 3300 K—closely approximating the exhaust conditions of main-stage rocket engines. Using this platform, an experimental water-injection system was developed to investigate the acoustic suppression mechanisms of high-temperature supersonic plumes. The study focuses on the payload-bay acoustic environment, where upward-propagating jet noise imposes significant structural loading during liftoff. Controlled experiments systematically examined the influence of both injection velocity and water-to-plume mass-flow-rate ratio (MFRR) on jet noise, with MFRR ranging from 0 to 12 and injection velocity from 8.2 to 33.1 m/s. Results reveal two key behaviors not previously reported in the literature: 1) at low MFRR, water injection can slightly increase high-frequency noise due to enhanced fine-scale turbulence generated by plume–water interaction; 2) at higher MFRR, the maximum achievable noise reduction is governed by injection velocity, as higher velocities improve water–plume coupling, promote faster vaporization, and form denser mist regions. The resulting water mist further suppresses high-frequency noise through viscous and relaxation absorption, although the detailed quantitative behavior requires further investigation. These findings provide experimental insight and scaling references for optimizing water-injection parameters to improve acoustic suppression efficiency and reduce payload-bay acoustic loading in high-temperature rocket exhaust environments.

Theoretical and experimental investigation of shaped charge jet penetration in soil targets with varying moisture content

Purpose For the purpose of preventing corrosion in metals and alloys, coating techniques are given priority. The prevention of copper corrosion in NaCl solutions by various inhibitor compounds using the spin coating process has recently undergone substantial research. The development of eco-friendly corrosion inhibitors is crucial to replacing toxic conventional coatings. This study introduces a novel zinc–curcumin (Zn-CU) complex coating for enhancing copper corrosion resistance. The synergistic effect of zinc ions and curcumin’s antioxidant properties provides a sustainable, nontoxic protective layer. This research bridges the gap in green corrosion inhibitors by proposing a biodegradable, metal–organic hybrid coating with industrial potential for marine and electronic applications. The purpose of this study is to synthesize Zinc -Curcumin metal complex and to evaluate its corrosion resistance characteristics. Design/methodology/approach In a solution of 3.5% NaCl for three days, a Zn-CU metal complex was produced, and its resistance to copper corrosion was examined. A Zn-CU metal complex was prepared and its corrosion resistance towards copper corrosion in 3.5% NaCl solution for three days was studied. The corrosion resistance property of the synthesized compound was examined by potentiodynamic polarization, SEM and EDX. Metal complex coating on copper substrate was performed by spin coating technique using a nontoxic binder polyvinylpyrrolidone (PVP). Findings Experimental investigations showed that Zn–CU/PVP reduces copper corrosion and attains 85% inhibition efficiency. Utilizing organic inhibitor coatings is one contemporary method for defending metals against corrosion caused by acids, bases or neutrals. They serve as a barrier or protective layer depending on the construction either as an insoluble chelate barrier created by chemisorption or produced by physisorption in the metal/electrolyte interphase. The morphology (shape, branching or conformation), aromaticity and conjugation, bonding strength to the metal substrate, the presence of heteroatomic nitrogen, oxygen and/or sulphur and the type and number of bonding atoms or groups are some of the factors that affect an organic molecule’s ability to inhibit metal corrosion. Research limitations/implications Synthesis of less toxic green anticorrosive coatings by incorporating plant and natural extracts are not only eco-friendly but also provide excellent corrosion prevention. This work mainly focussed on the synthesize of an eco-friendly metal complex of zinc by incorporating curcumin (Zn-CU). The synthesized compound was coated on copper surface using a binder PVP by spin coating method. Corrosion inhibition efficiency of Zn-CU increased with the concentration of metal complex. The corrosion resistance was up to 85% with 300 mg/L−1 Zn-CU/PVP at 30°C. The corrosion resistance property of Zn-CU metal complex in corrosive environment of 3.5% NaCl for copper has been tested by polarization analysis, SEM and EDX. Electrochemical tests confirmed that Zn-CU complex showed better corrosion inhibition property. SEM supported by EDX confirmed the stability and elemental composition of coating on the copper surface. Practical implications The practical implications include: development of a green chemistry approach in corrosion resistance; showcase of ways that metal protection can be augmented by bioactive compounds such as curcumin; and provision of alternatives to toxic corrosion inhibitors. Social implications Zinc and its compounds are widely used for corrosion protection due to their ability to act as sacrificial anodes. Zinc-based coatings provide effective corrosion resistance by forming passive layers that inhibit metal oxidation. Recent studies have explored the potential of zinc–organic complexes in corrosion inhibition, but their full potential remains under investigation. Recent research has focused on the synergistic effect of combining curcumin with zinc to enhance corrosion resistance (Rajendran et al., 2025; Xue et al., 2023). Zn-CU complexes offer multiple advantages, including improved stability, better adhesion to the metal surface and enhanced antioxidant properties (Mourya et al., 2019; Ashwini et al., 2023). However, there is limited literature on their application as protective coatings for copper surfaces, presenting a research gap that this study aims to address. The goal of this work is to investigate the ability of a Zn-CU complex coating to inhibit corrosion on copper in 3.5% NaCl solution using potentiodynamic polarisation and SEM/EDX. Originality/value This coating provides excellent corrosion inhibition owing to the synergistic effects of Zn²+ ions, released from sacrificial anode and curcumin, which facilitates the protection of metals from corrosion. Zinc gives sacrificial protection that minimizes metal oxidation, while curcumin is the organic inhibitor that results in a stable protective layer that hinders the initiation of corrosion. Curcumin can reduce the oxidative stress on metal surfaces due to its antioxidant properties and also inhibit the growth of bacteria that can cause corrosion. In contrast to conventional chemical inhibitors (e.g. chromates), curcumin is biodegradable and nontoxic; thus, it is considered as a sustainable approach.

Abstract Anchors are used to connect different structural and non‐structural components to reinforced concrete structures. Anchorages when subjected to tension loading might fail in different failure modes, with concrete cone breakout (CCB) being one of the most common. The capacity of an anchorage against CCB can be significantly enhanced by means of anchor reinforcement (also known as supplementary reinforcement in Europe) placed strategically around the anchorage. In case of anchorage with anchor reinforcement, as the crack corresponding to CCB intercepts the anchor reinforcement, it starts to act as a stitching system between the structural body and the breakout body. There are different models available in design codes and literature to calculate the capacity of cast‐in anchorages, like embed plates, with cast‐in anchor reinforcement. Using post‐installed anchors is a popular choice due to their flexibility in terms of design and setting location. However, only overly conservative models are available in standards for post‐installed anchors with anchor reinforcement. This is primarily due to the lack of experimental evidence. Therefore, an experimental investigation was performed in this work using post‐installed anchors with cast‐in anchor reinforcement under tension loading to understand the behavior and verify the performance of post‐installed anchorages when used in conjunction with cast‐in anchor reinforcement. Three types of post‐installed anchors with different load‐transfer mechanisms, namely adhesive anchors, undercut anchors, and torque‐controlled expansion anchors, were tested under concentric tension loading varying the amount and layout of the cast‐in anchor reinforcement. In general, the behavior of post‐installed anchorages with anchor reinforcement was found to be similar to the behavior of cast‐in anchorages with anchor reinforcement. Higher load capacity and larger failure displacement were observed for all three types of anchors when anchor reinforcement was used compared to the reference tests without any anchor reinforcement.

Unraveling the structural, optoelectronic and vibrational properties of L-phenylalanine L-phenylalaninium malonate crystal: An experimental and theoretical approach.

Aims: This study evaluated the alcoholic leaf extract of Calotropis gigantea for its effects on Aphis gossypii infestation, chili yield, and natural enemy arthropod diversity under field conditions. Study Design: This study was an experimental investigation conducted in the laboratory using a completely randomized design (CRD) and in the field using a randomized complete block design (RCBD). Place and Duration of Study: The study was conducted at the Plant Pest Science Laboratory, Faculty of Agriculture, and the Chemistry Laboratory, Faculty of Mathematics and Natural Sciences, Tadulako University, as well as in the field at Lolu, Sigi Biromaru District, Sigi Regency. The research was carried out from May to October 2025 Methodology: This study was an experimental investigation conducted under laboratory conditions. Alcohol-macerated leaves of C. gigantea collected from the Palu Valley were evaluated through laboratory assays at concentrations of 1.0, 0.5, 0.25 mg L⁻¹ and control, and field trials at 40, 30, 20, 10, and 5 mg L⁻¹, including positive and negative controls. Applications were initiated at 3 weeks after transplanting and repeated at 7-day intervals for six applications. Observed parameters included aphid population density, infestation intensity, diversity of natural enemies, and chili yield. Results: The leaf extract of C. gigantea exhibited strong toxicity against A gossypii, with an LC₅₀ of 0.513 µg L⁻¹. Field application significantly reduced aphid population density and infestation intensity in a dose-dependent manner. High extract concentrations 40 g/l (K4) achieved suppression levels comparable to synthetic insecticides (K+), while untreated plots showed progressive population increases. Diversity indices of natural enemies were not significantly affected by extract treatments, indicating minimal non-target effects. Crop yield increased significantly with extract application, with the highest dose producing yields equivalent to synthetic insecticide controls. Conclusion: C. gigantea leaf extract effectively controlled. A. gossypii in a dose-dependent manner, with high concentrations achieving suppression comparable to synthetic insecticides. The extract did not negatively impact natural enemy diversity and significantly increased chili yield, highlighting its potential as an environmentally friendly and sustainable alternative for integrated pest management.

Photophysical and Photochemical Properties of a Curcumins Family: A Combined Computational and Experimental Investigation

Composite foam sandwich structures are widely employed in aerospace and other advanced engineering fields due to excellent mechanical properties. During manufacturing and service, composite foam sandwich structures are inevitably subjected to various impacts, including flexible and repeated impacts, which introduce complex damage and severely threaten structural integrity and service life. This study presents an experimental investigation into the response of CFRP/PMI foam sandwich panels subjected to single and repeated flexible impacts. The impact response, energy absorption efficiency, and interlaminar damage evolution (characterized via C-scan) were analyzed under varying impact energies and numbers of impacts. The residual compressive strength after impact was further investigated through compression-after-impact (CAI) tests on impacted and inspected foam sandwich panels. Residual strength values and failure modes of the panels were obtained under different impact energies and numbers of impacts. In addition, correlations between single-impact energy and repeated impacts at equivalent damage levels were established. The results indicate that a limited number of repeated low-energy impacts resulted in damage comparable to that from a moderate-energy single impact, while a greater number of such repeated impacts produced damage equivalent to a high-energy single impact.

Experimental Investigation and Computational Modeling of Zinc-Based Alloys for Bioresorbable Cardiovascular Stents

Abstract This study addresses friction and wear challenges in finger seals for aero-engines and high-speed machinery via pin-on-disc tests. Laser-fabricated circular textures with varying diameters (200~400 μm) and densities (5%~30%) on GH4169 discs were tested against GH605 pins under dry friction. Real-time friction monitoring and SEM/EDS analyses revealed texturing mechanisms: debris trapping mitigated abrasive wear, reducing friction and wear. The optimal performance was achieved at a 200 μm diameter and 10% density, with a 17.45% reduction in friction coefficient, a 42.17% decrease in wear depth, and the formation of a uniform transfer film for stable contact. Excessive density (30%) induced stress concentration via reduced contact area, worsening wear; large diameters (400 μm) caused impact loads from insufficient contact units, increasing friction fluctuations. The synergy of debris trapping, contact stress regulation, and transfer film formation defines the texturing benefit. Results offer experimental guidance for high-speed/high-load finger seal surface design.

Diverse quantum phenomena have been observed in TSn4transition metal (T) stannides, including superconductivity, nontrivial topology, and large magnetoresistance (MR) at low temperatures. Here, we report the experimental and theoretical investigation of tetragonalβ-IrSn4(space groupI41/acd) with the lattice parametersa= 6.362(3) Å andc= 22.723(0) Å. The temperature dependence of the electrical resistivity indicates thatβ-IrSn4is a good metal with Fermi-liquid behavior above the superconducting transition atTc∼ 0.7 K. Magnetic susceptibility measurements indicate it is non-magnetic. However, positive transverse MR with linear field dependence is observed. AtT= 2 K andΜ0H= 14 T, the MR reaches 700% without sign of saturation. Shubnikov-de Haas oscillations are observed from proximity detector oscillator measurements up to 60 T. We experimentally extract several frequencies, and through comparison to first-principles calculations, identify corresponding electronic bands. ForH//c, two strong oscillations,F1≈ 109 andF2≈ 302 T, allow us to determine effective masses 0.266m0and 0.300m0(m0is the free-electron mass), respectively. The topology of these bands is discussed.

ABSTRACT Electrocatalytic nitrate reduction reaction (NitRR) offers a promising route for hydroxylamine (NH 2 OH) synthesis under ambient conditions. However, the inherent activity‐selectivity trade‐off limits the overall performance. To overcome this challenge, a bimetallic NiMg‐MOF‐74 electrocatalyst is designed for NH 2 OH production via NitRR with high performance. Experimental and theoretical investigations have unraveled the synergy of dual active sites in promoting NO 3 − to NH 2 OH conversion. The electron‐sufficient Ni (2‐δ)+ site weakens the binding of *NH 2 OH intermediate and minimizes its excessive reduction to undesired NH 3 byproduct. Moreover, the electron‐deficient Mg (2+δ)+ site with higher charge density than Ni (2‐δ)+ facilitates hydration and hydrogenation steps of N─O species over proximal Ni (2‐δ)+ site, thus the overall activity for NH 2 OH formation is increased. The concurrently enhanced selectivity and activity result in a high Faradaic efficiency of 92.3% and an unprecedented NH 2 OH yield rate of 55.1 mg h −1 cm −2 in a flow reactor, which can be directly utilized for the preparation of value‐added oxime compounds. Further, the coupling of NitRR with photovoltaics in one system enables bias‐free NH 2 OH production with a high solar‐to‐NH 2 OH efficiency of 17.74%. Our work offers advanced electrocatalysts and new insights for sustainable NH 2 OH electrosynthesis.