Penetration Experiments Research Articles

Experimental and numerical investigation on penetration of clay masonry by small high-speed projectile

This study investigates a kind of masonry consisting of clay-fired brick (fc = 10 MPa; ρ=1.38g/cm3) and mortar (fc = 10 MPa; ρ=1.8g/cm3). Clay-fired brick masonry connotes a traditional construction material of old architecture and public buildings. We carried out penetration experiments in which four clay-fired brick walls employing two different patterns were subjected to impact from small high-speed projectile, i.e. 12.7 mm armor-piercing explosive incendiary projectile and material tests in which the static and dynamic compressive strengths of clay-fired brick and mortar were determined by quasi-static and SHPB (Split Hopkinson Pressure Bar) tests. The experimental data include hit and exit velocities, damage configuration of clay brick masonry and mechanical properties of material at low and high strain rates, though which influence of thickness and bonding patterns of wall on kinetic loss of bullet, the damage patterns of masonry observed experimentally and dynamic increase of material strengths are analyzed. To keep minimum boundary inconsistency with reality, full 3D detailed finite element model consisting of two different material is established. Sharing common nodes and employing automatic tiebreak contact are combined to reduce computational time usage of large-scale model. For description of clay-fired brick and mortar Riedel–Hiermaier–Thoma (RHT) material model is employed. Material parameter set is derived based on experimental data, available literature and engineering assumptions. The numerical simulations study the mesh resolution dependency of material model, reproduce the crucial phenomena of masonry in experiment acceptably and offer more time-resolved insight into motion of bullet in the process of penetration. The feasibility of means of constructing finite element model and applying RHT model to the masonry herein and analogous constructions is explored through numerical investigation.

SPH-FEM coupling simulation of rock blast damage based on the determination and optimization of the RHT model parameters

To improve the accuracy of the results of rock blast damage simulation, a numerical scheme of ascertaining and optimizing the Riedel–Hiermaier–Thoma (RHT) model parameters was developed. First, the RHT model was adopted to simulate limestone penetration experiments, and the 31 RHT model parameters were initially determined based on the published data and theoretical derivation. Subsequently, sensitivity analyses were conducted using the “controlled variable method” to optimally determine the parameters. Finally, the RHT model parameters and coupled smoothed-particle hydrodynamics (SPH)-finite element method (FEM) were employed to simulate the limestone blast damage. The results demonstrate that the relative sensitive parameters obtained by taking the penetration depth of the projectile as the investigation index are ρ 0, ρ s, p e, G, f ϕ, B, M, and F G. The proposed “constant-amplitude adjustment method” can guarantee the integrity of the parameter ascertainment to a certain extent. The blast simulations indicate that the RHT model parameters determined based on the penetration experiment have certain applicability for the blast simulation and that the coupled SPH-FEM algorithm has a great advantage over FEM or SPH and can realistically show the whole process of rock blasting.

Study on the failure mode of a sandwich composite structure under the combined actions of explosion shock wave and fragments

To improve the protective performance of structures in terms of explosive shock waves and fragment penetration, a foamed aluminum/UHMWPE fiber sandwich composite structure was designed. A “explosion+fragmentation” penetration experiment was used to study the failure mode of the structure and the failure mechanisms of materials, the effects of the core material combination and explosion distance were discussed, meanwhile, numerical simulation using LS-DYNA was adopted to simulate the timing and distribution law of the shock wave and fragments. The results show that the explosion distance is the main influencing factor for the timing, and the experimental and numerical results have a good consistency. When the structure was perforated completely by fragments, the front aluminum plate was damaged mainly by shear plugging, and the rear aluminum plate was broken largely by cracking and tearing. When the fragments arrived prior to the shock wave, the tearing damage to the rear aluminum plate was more obvious. The foamed aluminum absorbed the explosive energy through its own crushing deformation, and the fiber layer absorbed the kinetic energy of the fragments through its own tensile failure. Of the composite structures prepared herein, the composite structure consisting of foamed aluminum/foamed aluminum/UHMWPE fiber had the best protection performance.

Study on thermal runaway mechanism of 1000 mAh lithium ion pouch cell during nail penetration

The safety issues of lithium ion batteries (LIBs) have been serious as the popularity of LIBs in portable electronics and electric vehicles. It is necessary to understand the thermal runaway mechanism to effectively prevent thermal runaway. A series of nail penetration experiments are conducted to study the thermal runaway mechanism of lithium ion pouch cell in this work. It is observed that the pouch cell experiences four processes including nail penetration, internal short circuit, chemical reaction and thermal runaway during nail penetration. Additionally, four parameters, including state of charge (SOC), penetration speed, penetration position and nail diameter, are taken in the experiments to investigate the effect on thermal runaway. The results show that the cells with higher SOC and penetrated by bigger nail are easier to be triggered into thermal runaway and obtain higher temperature. The penetration position decides the location of the short circuit and the temperature distribution, and the steel nail has an influence on the temperature distribution of the cell. The results provide suggestions for the transportation, safe use and design of the cell.

Developing formulations for drug follicular targeting: Nanoemulsions loaded with minoxidil and clove oil

Drug vectorization to hair follicles favors skin drug penetration, contributing to the optimization of treatment of diseases as alopecia areata (AA). In this context, this work aimed to develop and characterize nano-sized minoxidil (MXD) formulations to sustained and target drug delivery to hair follicles for the optimization of AA treatment. Nanoemulsions were prepared by ultrasonication. The influence of 3 independent variables at 2 levels and 3 replicates of center point was evaluated, totalizing 11 experimental runs. Three optimized nanoemulsions were studied (NE 5, NE 6 and NE 8). Clove oil and Kolliphor® P188 were selected as oil phase and surfactant, respectively. Optimized nanoemulsions showed monomodal size distributions, mean droplet size of 10 nm with PdI smaller than 0,2 and stability against coalescence at room temperature and relative humidity levels around 50%. Nanoemulsions controlled drug release 2 times more effectively than control sample for at least 6 h, with the predominance of Higuchi release kinetic model. MXD skin penetration from nanoemulsions was raised by more than 9 times, compared with conventional ethanol-based solutions. Follicular drug penetration experiments showed that nanoemulsions containing MXD penetrated into hair follicles more than 26 times more efficiently than control sample, suggesting that the proposed clove oil-based nanoemulsions constitute a promising approach for the topical treatment of alopecia.

In-vitro evaluation of meloxicam permeation using response surface methodology

The influences of combination of different mechanisms of penetration enhancers (such as azone, sodium lauryl sulfate and menthol) on the percutaneous absorption of meloxicam formulations throughh rat skin were investigated using uniform deign and response surface methodology. The uniform design was applied to prepare systematic model formulations which were composed of three formulation factors: Azone (x1), sodium lauryl sulfate (x2), and menthol (x3). The result showed that azone had the highest potential influence on the penetration absorption of meloxicam, followed by sodium lauryl sulfate and menthol. With zero-order delivery, the required flux of meloxicam gel to maintain a therapeutic concentration was about 400 μg/hr/cm2. The result showed that the optimal addition concentration of azone at 4% to 6% could be obtained at high penetration rate and short lag time of meloxicam gel. It was shown that as the concentration of sodium lauryl sulfate increased from 0% to 12% the flux and cumulative amount at 48 hr increased and lag time decreased. On the other hand, menthol had the effect of a shorter lag time. To validate the predictive ability of the hypothesized model, the predicted formulations were prepared and penetration experiments were performed. The predicted formulations were developed for the transdermal drug delivery system.

Pore Structure Characteristics of Ultra-Low Permeability Reservoirs

Pore structure characteristics of ultra-low permeability reservoirs are studied in this paper. The impact of pore structure characteristics on permeability and reservoir development effect is analyzed by conventional and constant-rate mercury penetration experiments. The results show that the frequency curve of pore radius distribution of ultra-low permeability reservoirs has little change with permeability. The average pore radius in ultra-low permeability reservoirs with different permeability levels had little difference, and its distribution ranges from 98.5 to 110.1 μm. With decrease of permeability, the frequency distribution curves of throat radius and pore-throat ratio change significantly. The peak value of throat radius curve moves to the left and increases significantly, and the average throat-radius distribution decreases from 2.33 to 0.91 μm. However, the impact of pore-throat ratio on permeability is contrary to that of throat radius. Both throat radius and pore-throat ratio has strong correlation with permeability, and they are in exponential relationship. With the in-depth study, it is found that seepage capacity of reservoirs is restricted mainly by throat radius and pore-throat ratio. When throat radius decreases to less than 1 μm and pore-throat ratio increases more than 130, permeability decreases sharply and obviously. When permeability is less than 2 × 10−3μm2, the proportion of fine throats and medium throats under the condition of effective water injection is significantly lower, and the production of single well and the recovery efficiency by water flooding in ultra-low permeability reservoirs are low. The study explains effectively the fundamental reason for the poor efficiency of production and recovery of ultra-low permeability reservoirs from the mechanism.

A New Near‐Infrared Long Persistent Luminescence Material with Its Outstanding Persistent Luminescence Performance and Promising Multifunctional Application Prospects

AbstractIn this work, a novel near‐infrared (NIR) persistent luminescence (PersL) material Na2CaGe5SiO14 (NCGSO):Cr3+ is designed and prepared. The phase composition and crystal structure are analyzed by X‐ray diffraction (XRD) and Rietveld structural refinement. The band gap of NCGSO is calculated to be 4.245 eV by density functional theory (DFT) and confirmed by diffuse reflection spectroscopy (DRS). It is determined by the photoluminescence (PL) spectra, X‐ray absorption near‐edge spectroscopy (XANES), and time‐resolved emission spectra (TRES) that three Ge4+ sites can be superseded simultaneously when Cr3+ ions are doped. In addition, the PL, photoluminescence excitation (PLE), and PersL performance are analyzed systematically. Under the radiation of 254 nm ultraviolet (UV) lamp, the samples exhibit excellent PL and PersL performance in the range of 600–900 nm, and the optimal afterglow duration lasts for more than 10 h. According to results, a possible mechanism is proposed to explain the PersL phenomenon. In the end, a set of information encrypted digital labels is designed and biological tissue penetration experiments are performed. The results reveal the potential of NCGSO:Cr3+ for information encryption and biological imaging applications.

Dynamic Mechanical Damage and Non-Shock initiation of a New Polymer Bonded Explosive during Penetration.

Complexities of heating mechanisms make it difficult to investigate the safety of a polymer bonded explosive (PBX) charge of earth-penetrating-weapons (EPWs) during penetration. In this paper, the dynamic damage and non-shock initiation of PBX1314 (60 wt % hexahydro-1, 3, 5-trinitro-1, 3, 5-s-triazine (RDX), 16 wt % aluminum, 24 wt % hydroxy-terminated polybutadiene (HTPB)) during penetration is investigated through experiments and simulations. In the experiments, steel projectiles filled with PBX1314 are launched to penetrate concrete targets. In the results, non-shock initiations occur on the tail surface of PBX1314 along with mechanical damage of the tail and middle part of PBX1314. A dynamic damage and initiation model is proposed to characterize the effects of microcracks on the mechanical and thermal responses of PBX1314. Investigation based on the model suggests that microcrack interfacial friction plays significant roles in damage, heat generation and localization in PBX1314. A non-shock initiation criterion is developed based on macroscale variables in PBX1314. Numerical simulations of the penetration experiments are performed by using the proposed model and criterion. The mechanical damage and non-shock initiation of PBX1314 in the experiments are successfully predicted. The simulation results indicate that the tail of PBX1314 impacts the projectile repeatedly during penetration. Finally, the initiation criterion is satisfied because of frictional heat localization near microcrack surfaces and initiation is activated in the tail of PBX1314.

Facility for the Characterization of Planar Multilayer Thin Film Superconductors

The maximum accelerating gradient of SRF cavities can be increased by raising the field of full flux penetration, H vp . One method which can potentially increase H vp is to use structures consisting of alternating layers of superconductors and insulators (SIS). Magnetometry is commercially available but consists of limitations, such as SQUID measurements which apply a field over both superconducting layers, so H vp cannot be measured. If H vp is to be measured for SIS coatings, a parallel, local magnetic field must be applied from one plane of the sample, with no field on the opposing plane. A field penetration experiment has been developed at Daresbury laboratory allowing H vp to be measured using a local, parallel DC magnetic field. Using a field much smaller than the sample allows limitations such as edge effects to be significantly reduced. By increasing the field, H vp can be found by using 2 hall probes, one either side of the sample. The experiment was designed to use a variable temperature insert (VTI) to run in a cryogen free environment, but has been running in a LHe bath for thermal stability.

Rice bran protein-based nanoemulsion carrier for improving stability and bioavailability of quercetin

Rice bran protein with good hydrophilicity and high surface activity was utilized as an emulsifier to stabilize nanoemulsions. In this experiment, under the conditions of 3% RBP content and pH 9.0, the rice bran protein-based nanoemulsions (RBP NEs) were shown to possess the smallest droplet size and the best stability. Adding quercetin at 3 mg/mL under these conditions led to the formation of nanoemulsions with a smaller droplet size and a higher incorporation rate. The quercetin-loaded rice bran protein-based nanoemulsion (QE-RBP NEs) demonstrated good stability under alkaline conditions and low salt ion concentrations. After in vitro digestion and cell penetration experiments, it was concluded that encapsulation in the RBP NEs led to an increased quercetin bioavailability, which reached 12.70 ± 0.12%. The nanoemulsion encapsulation also reduced the toxicity of quercetin to cells and increased the cell penetration of quercetin, which reached 4.93 ± 0.01 × 10−6 cm/s. In addition, both RBP NEs and QE-RBP NEs have a storage period of 14 days. This work confirms that RBP NEs can be used as an effective carrier to deliver biologically active molecules.

The effect of probe geometry on rind puncture resistance testing of maize stalks

BackgroundStalk lodging (breaking of plant stems prior to harvest) is a major impediment to increasing agricultural yields of grain crops. Rind puncture resistance is commonly used to predict the lodging resistance of several crop species. However, there exist no standard operating procedures or suggested protocols for conducting rind penetration experiments. In addition, experimental details of rind penetration tests such as the shape and size of the penetrating probe are rarely reported in the literature. This has prevented meta-analysis of results and has likewise prevented key findings of past studies from being replicated. As a first step towards establishing an agreed upon measurement standard for rind puncture resistance this study investigates the effect of the puncturing probe’s geometry on test results.ResultsResults demonstrate that probe geometry has a significant impact on test results. In particular, results showed that a 2 mm diameter chamfered probe produced stronger correlations with stalk bending strength than a 1.5 mm diameter pointed probe. The chamfered probe was also more strongly correlated with geometric features of the stalk that are known to influence stalk lodging resistance (e.g., rind thickness, diameter and section modulus). In addition, several alternative rind penetration metrics were investigated, and some were found to be superior to the most common rind penetration metric of maximum load.ConclusionsThere is a need in the agricultural and plant science community to create agreed-upon operating procedures and testing standards related to mechanical traits of plant stems. In particular, a standardized probe geometry and insertion rate for rind penetration studies are needed to enable greater interoperability and meta-analysis of results. Probe shape and size should be reported in any study conducting rind penetration tests as these factors significantly impact test results.

Folyadékbehatolásos vizsgálatok befolyásoló tényezőinek hatása a vizsgálat eredményeire

A roncsolásmentes vizsgálatok napjaink egyik legfontosabb vizsgálati eljárásai közé tartoznak. Egyik legnagyobb előnyük a többi vizsgálathoz képest, hogy folyamatos üzemelés közben is lehetőségünk nyílik a vizsgálat elvégzésére anélkül, hogy magát az folytonos üzemelést megszakítanánk. Jelen tanulmányban a folyadékbehatolásos, más néven penetrációs vizsgálatokkal végzett kísérletek eredményeit, és a hibák összehasonlítására szolgáló számítógépes eljárást mutatjuk be.

Dissipative Particle Dynamics Modeling of Polyelectrolyte Membrane-Water Interfaces.

Previous experiments of water vapor penetration into polyelectrolyte membrane (PEM) thin films have indicated the influence of the water concentration gradient and polymer chemistry on the interface evolution, which will eventually affect the efficiency of the fuel cell operation. Moreover, PEMs of different side chains have shown differences in water cluster structure and diffusion. The evolution of the interface between water and polyelectrolyte membranes (PEMs), which are used in fuel cells and flow batteries, of three different side-chain lengths has been studied using dissipative particle dynamics (DPD) simulations. Higher and faster water uptake is usually beneficial in the operation of fuel cells and flow batteries. The simulated water uptake increased with the increasing side chain length. In addition, the water uptake was rapid initially and slowed down afterwards, which is in agreement with the experimental observations. The water cluster formation rate was also found to increase with the increasing side-chain length, whereas the water cluster shapes were unaffected. Water diffusion in the membranes, which affects proton mobility in the PEMs, increased with the side-chain length at all distances from the interface. In conclusion, side-chain length was found to have a strong influence on the interface water structure and water penetration rates, which can be harnessed for the better design of PEMs. Since the PEM can undergo cycles of dehydration and rehydration, faster water uptake increases the efficiency of these devices. We show that the longer side chains with backbone structure similar to Nafion should be more suitable for fuel cell/flow battery usage.

Unique morphology and mechanical property of Chinese sturgeon (Acipenser sinensis) fish skin.

Chinese sturgeon (Acipenser sinensis) fish skin is an excellent natural material with remarkable mechanical properties owing to the unique structures of the helical stacking fibres. In this work, the authors studied the potential role of the sturgeon fish skin in the protective function through testing and analysed the structural features and mechanical properties of the stratum compactum in the fish skin. Scanning electron microscopy images of the sturgeon fish skin revealed that the skin was primarily composed of the stratum compactum. The stratum compactum was characterised by the helically arranged fibre structures and the helical-ply angle decreased from the anterior region of the fish body to the posterior region. Mechanical tests containing tension and penetration experiments demonstrated that the stratum compactum provided the sturgeon fish skin the capability to effectively resist bite and laceration by predators. Furthermore, the experimental results also confirmed that the sturgeon fish skin showed two distinct mechanisms against tension and penetration. These findings may provide a novel biomimetic design template for both flexible and tough body armour.

Study on effective protective area of ceramic composite target

In order to study the difference of ballistic performance in different area of ceramic composite spaced targets, penetration experiment of two targets is conducted. Based on the experiment results, simulation method is used with the dynamic analysis software ANSYS/LS-DYNA, by which the process and mechanism of armour protection is discussed, as well as the effect of unit shape on ballistic performance of targets. It is revealed that the segmentation degree of ceramic cone accounts for the difference in ballistic performance. Besides, the critical points of effective protection is calculated, and the effective protective area of both targets is measured.

CgSCD1 Is Essential for Melanin Biosynthesis and Pathogenicity of Colletotrichum gloeosporioides.

Colletotrichum gloeosporioides, an important phytopathogenic fungus, mainly infects tropical fruits and results in serious anthracnose. Previous studies have shown that melanin biosynthesis inhibitor can inhibit the melanization of the appressoria of Magnaporthe grisea and Colletotrichum orbiculare, resulting in limited infection of the hosts. In this study, we identified and characterized a scytalone dehydratase gene (CgSCD1) from C. gloeosporioides which is involved in melanin synthesis. The CgSCD1 gene deletion mutant ΔCgscd1 was obtained using homologous recombination. The ΔCgscd1 mutant showed no melanin accumulation on appressoria formation and vegetative hyphae. Furthermore, the virulence of ΔCgscd1 was significantly reduced in comparison with the wild-type (WT) strain. Further investigations showed that the growth rate as well as germination and appressorium formation of ΔCgscd1 displayed no difference compared to the wild-type and complemented transformant Cgscd1com strains. Furthermore, we found that the appressorial turgor pressure in the ΔCgscd1 mutant showed no difference compared to that in the WT and Cgscd1com strains in the incipient cytorrhysis experiment. However, fewer infectious hyphae of ΔCgscd1 were observed in the penetration experiments, suggesting that the penetration ability of nonpigmented appressoria was partially impaired. In conclusion, we identified the CgSCD1 gene, which is involved in melanin synthesis and pathogenicity, and found that the melanization defect did not affect appressorial turgor pressure in C. gloeosporioides.

Experimental and numerical study on penetration-induced internal short-circuit of lithium-ion cell

Nail penetration test is an abuse test method to evaluate the thermal hazard of lithium-ion battery. The internal short-circuit is a direct cause of battery thermal runaway, while its mechanism has not been fully understood yet. In this work, the penetration-induced internal short-circuit of lithium-ion cell is studied through nail penetration experiments, numerical simulation, and cell separator thermal analysis. The results show that the nail plays a dual role in the penetration process for thermal runaway or non-thermal runaway cases, which determines the short-circuit current and heat dissipation. In addition, there are two types of temperature rise modes for thermal runaway case, the time intervals from the beginning of penetration to thermal runaway of these two modes are less than 5 s and 60 s, respectively. It can also be concluded that the cell terminal voltage is found to decay exponentially with time after penetration, while the fluctuations and rebound of terminal voltage during the nail penetration process are attributed to the partially interrupted internal short-circuit path. The results indicate that the Joule heat generated at short spot dominates the total heat generation inside lithium-ion cell with non-thermal runaway nail penetration cases.

Thermal Runaway Behavior of Lithium Iron Phosphate Battery During Penetration

The nail penetration experiment has become one of the commonly used methods to study the short circuit in lithium-ion battery safety. A series of penetration tests using the stainless steel nail on 18,650 lithium iron phosphate (LiFePO4) batteries under different conditions are conducted in this work. The effects of the states of charge (SOC), penetration positions, penetration depths, penetration speeds and nail diameters on thermal runaway (TR) are investigated. And the accelerating rate calorimeter is applied to reveal the thermal runaway mechanism. The experimental results show that the higher the SOC of the battery, the higher the possibility and risk of TR of the battery, and there seems to be a critical penetration depth where TR occurs. The battery exhibits higher average temperature at higher penetration speeds. Whether the battery get into TR is not related to the penetration speed. When the penetration location near the positive pole and negative pole,the risk of thermal runaway is much higher than the centre position of the battery. The larger the diameter of the nail, the lower the overall temperature of the battery. What’s more, the results of the penetration tests under the condition of parameter coupling shows that the average temperature of battery are greatly affected by the parameters of SOC, penetration position. The temperature of the LiFePO4 battery is within 200°C when the TR occurs induced by the penetration, which is mainly due to the incomplete exothermic reaction inside the battery.

Evaluation of the Solid Dispersion System Engineered from Mesoporous Silica and Polymers for the Poorly Water Soluble Drug Indomethacin: In Vitro and In Vivo.

This work explored absorption efficacy via an in vivo imaging system and parallel artificial membrane penetration in indomethacin (IMC) solid dispersion (SD) systems. Two different polymer excipients—hydroxypropyl methylcellulose (HPMC) and Kollicoat IR as precipitation inhibitors (PIs)—combined with mesoporous silica nanoparticles (MSNs) as carriers were investigated. The IMC–SDs were prepared using the solvent evaporation method and characterized by solubility analysis, infrared (IR) spectroscopy, powder X-ray diffraction (PXRD), field emission scanning electron microscopy (FESEM), and differential scanning calorimetry (DSC). It was confirmed that IMC successfully changed into an amorphous state after loading into the designed carriers. The in vitro release and stability experiments were conducted to examine the in vitro dissolution rates of IMC–SDs combined with HPMC and Kollicoat IR as PIs which both improved approximately three-fold to that of the pure drug. Finally, in vivo studies and in vitro parallel artificial membrane penetration (PAMPA) experiments ensured the greater ability of enhancing the dissolution rates of pure IMC in the gastrointestinal tract by oral delivery. In brief, this study highlights the prominent role of HPMC and Kollicoat IR as PIs in MSN SD systems in improving the bioavailability and gastrointestinal oral absorption efficiency of indomethacin.