Penetration Characteristics Research Articles

Numerical simulation of penetration behavior of RHA target with biconical liner

The AUTODYN-2D simulation software was used to study the jet formation of single-cone and biconical shaped charge liner and the damage influence on the RHA target. The numerical simulation results show that compared with the typical single-cone shaped charge structure, the jet head formed by the biconical liner is faster and has better penetration performance on the RHA target. On this basis, the influence of standoff, liner cone angle and line thickness on the penetration characteristics of RHA target under biconical shaped charge was studied. The simulation results show that when the standoff increases from 2.0CD to 3.0CD, the penetration depth increases gradually. When the upper cone angle is 30° and the lower cone angle increases from 40° to 60°, the penetration depth of the formed jet to the target decreases gradually. When the liner thickness increases from 5mm to 6mm, the penetration depth is obviously improved.

Skin substitutes based on gellan gum with mechanical and penetration compatibility to native human skin.

The study reports on a simple system to fabricate skin substitutes consisting of a naturally occurring bacterial polysaccharide gellan gum. Gelation was driven by the addition of a culture medium whose cations induced gellan gum crosslinking at physiological temperature, resulting in hydrogels. Human dermal fibroblasts were incorporated in these hydrogels and their mechanical, morphological, and penetration characteristics were studied. The mechanical properties were determined by means of oscillatory shear rheology, and a short linear viscoelastic regime was noted up to less than 1% of strain amplitude. The storage modulus increased with an increasing polymer concentration. The moduli were in the range noted for native human skin. After 2 weeks of fibroblast cultivation, the storage moduli showed signs of deterioration, so that a culture time of 2 weeks was proposed for further studies. Microscopic and fluorescent staining observations were documented. These depicted a crosslinked network structure in the hydrogels with a homogeneous distribution of cells and an assured cell viability of 2 weeks. H&E staining was also performed, which showed some traces of ECM formation in a few sections. Finally, caffeine penetration experiments were carried out with Franz diffusion cells. The hydrogels with a higher concentration of polymer containing cells showed an improved barrier function against caffeine compared to previously studied multicomponent hydrogels as well as commercially available 3D skin models. Therefore, these hydrogels displayed both mechanical and penetration compatibility with the ex vivo native human skin.

Chloride penetration in reinforced slag-based concrete beams under combined effects of loads and drying–wetting cycles

The use of concrete incorporating slag is necessary due to global environmental concerns, but the decrease in concrete durability caused by environments rich in chloride ions requires more advanced concrete mix designs, especially in coastal areas. The aim of this study was thus to assess the influence of slag addition on the transport of chloride ions in reinforced concrete (RC) beams under sustained bending moments, considering two conditions of environmental chlorine exposure: drying–wetting cycles and soaking. The results showed that the chloride diffusion coefficient (CDC) increased in tension zones and decreased in compression zones when the sustained bending load in the concrete beam was increased. However, it was also found that the addition of slag can significantly reduce the chloride diffusion depth and CDC for both environmental conditions, with a more significant effect under drying–wetting cycles. The chloride concentration on the surface of slag concrete in the compression zone was greater than that in the tension zone and greater than that in both the tension and compression zones of the ordinary concrete. A prediction model was established for describing the chloride penetration characteristics of concrete beams subjected to sustained bending moment. The proposed model is a reasonable approach for predicting chloride distribution in RC beams with slag addition subjected to bending moments.

Preliminary design and techno-economic assessment of a trigeneration system integrated with compressed air and chemical energy storage

The advantages of compressed air energy storage (CAES) have been demonstrated by the trigeneration system with the characteristic of high penetration of renewable energy. However, since the irreversible loss of compression heat occurs during the overall operation processes of CAES, the development of CAES with high energy efficiency has been hindered by the conventional conversion pathway of compression heat. Therefore, a trigeneration system integrated with compressed air and chemical energy storage is proposed in this study to improve energy utilization efficiency. The compression heat is converted into H2 and CO via the endothermic methanol decomposition reaction to improve its energy level during the charging process, and then the syngas production can be used for air preheating during the discharging process. The parametric analysis is first performed to investigate the technical and economic feasibility of the system. Subsequently, the multi-objective optimization is conducted to identify the tradeoffs in the thermo-economic performance of the system and acquire the optimal values of operating parameters. Notably, the proposed system with a computed exergy efficiency of 43.31% and levelized cost of energy (LCOE) of 97.53 $/MWh is selected as the most compromise solution by the decision maker of Technique for Order Preference by Similarity to an Ideal Solution among the Pareto optimum fronts, which are 8.47% higher than the exergy efficiency and 7.39 $/MWh lower than the LCOE under the design conditions.

Identification of Impact Frequency for Down-the-Hole Drills Using Motor Current Signature Analysis

In rotary-percussion drilling, the impact frequency is a crucial variable that is closely linked to operational factors that determine the efficacy of the drilling process, such as the rate of penetration, bit wear, and rock mass characteristics. Typical identification methods rely on complex simulation models or the analysis of different sensor signals installed on specially adapted setups, which are difficult to be implemented in the field. This paper presents a novel study where the impact frequency is identified by motor current signature analysis (MCSA) applied to an induction motor driving a DTH drilling setup. The analysis of the case study begins with the definition of characteristic drilling stages where the pressure and sound signals allow the detection of an impact frequency of 14.10 Hz, which is then used as a reference to validate three MCSA identification approaches. As a result of the analysis, the envelope approach is the most robust for nearly real-time implementations considering its simplicity and range of coverage. Experimental results provide evidence about the feasibility of the proposed MCSA methods to be integrated into Measurement-While-Drilling (MWD) systems to improve drilling condition monitoring and rock mass characterization.

Water and chemical penetration characteristics of graded geopolymer concrete

The present study deals with identifying water, chloride and sulphate penetration characteristics of ambient cured graded GPC and the same is compared with conventional concrete. Geopolymer concrete is produced by adding source materials rich in silica and alumina such as Fly Ash (FA) and Ground Granulated Blast Furnace Slag (GGBS) with strong alkaline solutions, such as sodium hydroxide (NaOH) and sodium silicate (Na2 SiO3). Incorporation of GGBS in Fly ash based Geopolymer Concrete (GPC) shows promising results in terms of fresh and hardened concrete properties under ambient cured conditions. Grading GPC is used in the present work as the grade identification of concrete are very important in structural applications. Water penetration characteristics and chemical exposure of concrete have been a contentious issue because of presence of capillary pores and pore structure. Refinement in pore structure is possible with addition of cementitious materials to concrete. Since GPC, i.e., no cement concrete is composed of polymerization of pozzolanic materials under high alkaline medium, durability studies need to be studied rigorously for practical applications. Water penetration properties of GPC is assessed through water absorption test, sorptivity test and permeability test. Chloride penetration characteristics also estimated using Rapid Chloride Penetration Test (RCPT). Aggressive environment action on GPC is measured by exposing specimen to MgSO4 and Na2SO4 solution. Sulphate exposure on GPC is evaluated through physical observation, changes in weight, strength and elongations. The results of investigation indicated that compact pore structure of higher-grade GPC has similar penetration characteristics as that of conventional concrete. Further, it is noticed that chloride permeability decreases with curing age and with increase in grade of GPC. The same is further confirmed through formation of Friedel’s salt in microstructure of GPC observed through Scanned Electron Microscope (SEM) and Energy Dispersive X ray Spectrum (EDX). Microstructure of higher grade of GPC shows slight traces of ettringite, giving a clear indication of better resistance to sulphate attack compared to conventional concrete.

Numerical Simulations of Reactive Material Double-Layered Liner Shaped Charge Penetrating Steel Target

The jet formation and penetration behaviors of shaped charge with a reactive material double-layered liner (RM-DLL) are presented in this paper based on the AUTODYN-2D code. Numerical results show that the wall thickness ratio of the RM-liner to the metal liner has a significant influence on the formation and penetration characteristics of composite jet. As the wall thickness ratio increases, the tip velocity of composite jet, the pressure on the RM-liner, and the temperature of RM-elements decrease. The effect of the wall thickness ratio on the penetration performance of RM-DLL shaped charges against steel targets significantly depends on the RM-initiation delay time (τ). The penetration depth (PD) of the composite jet with titanium liner into the steel target is limited. In the case of the RM-tungsten liner, the RM-mass following into the penetration crater is very small. In the case of the RM-copper liner, the penetration capability of composite jet is well matched with the mass of follow-thru RMs. Compared with the PD, the standoff has a more significant impact on the RM-mass entering the penetration hole.

Effect of Different Pre‐Gelatinization Treatments on the Properties of Acidified Mung Bean Starch

AbstractMicrowave radiation processing technology is an emerging technology with good penetration, uniform heating, and rapidity characteristics. After microwave wet heat treatment, the viscosity of starch decreased, and the gelatinization temperature changed the granule morphology, crystalline properties, and chemical structure of starch, resulting in changes in the physical and chemical properties of starch. It can effectively improve the sensory quality of food and prolong the shelf life of starch products. It is widely used in food, pharmaceutical, agriculture, and other industries. The pre‐gelatinized starch showed irregular shape, rough surface, and apparent edges and corners. Moreover, the starch particles' crystal structure is destroyed, crystallinity decreased to 11.43%–14.91%, and no new groups are formed. The starch granules changed from an ordered structure to a disordered structure, and the order degree decreased to 0.998–1.025. The enthalpy decreased to 2.22–4.32 J/g, the gelatinization temperature increased to 88.53–94.43 °, and the viscosity decreased significantly. After pre‐gelatinization, the amylose content decreased to 13.84%–16.25%. At 90 °, the solubility and swelling degree decreased to 2.48%–7.33% and 16.80%–17.81%, respectively. The freeze‐thaw water precipitation rate increased to 41.92%–59.35%, the water‐holding capacity increased by 3 times and transparency increased to 93.60%–95.84%.

Characteristics of penetration and distribution of a liquid jet in a divergent cavity-based combustor

The atomization process of a liquid jet in a divergent cavity-based combustor was investigated experimentally using high-speed photography and schlieren techniques under a Mach number 2.0 supersonic crossflow. Gas-liquid flow field was studied at different divergent angles and injection schemes. It is found that complex wave structures exist in the divergent cavity-based combustor. The spray field can be divided into three distinct zones: surface wave-dominated breakup zone, rapid atomization zone and cavity mixing zone. A dimensionless spray factor is defined to describe the concentration of spray inside the cavity qualitatively. As a result, it is revealed that for the large divergent angle cavity, the injection scheme near the upstream inlet has a higher penetration depth but a lower spray distribution, where the injection scheme near the cavity has a more spray distribution. For the small divergent angle cavity, the injection scheme near the upstream inlet also has a higher penetration depth and the injection scheme near the start point of the divergent section has a more sufficient spray distribution. The small divergent angle cavity-based combustor with the upstream wall transverse injection is an optimized injection scheme to improve both penetration and spray distribution inside the cavity. Finally, a penetration depth formula is proposed to explain the spray and distribution behaviors in the divergent cavity-based combustor.

The Effects of Waste Tire Rubber on Penetration, Softening Point, Viscosity, Ductility, Flash Point, Specific Gravity, Solubility and Aging of Bitumen Used In Kenya

This study was carried out to assess the effect of rubber on conventional bitumen used in road construction in Kenya. This study aimed at characterizing the effects of modifying bitumen with waste-crumbed rubber. The properties of penetration, softening point, viscosity, ductility, solubility, flash point,specific gravity and aging characteristics of bitumen were analysed. The samples of tire rubber were obtained from the dump sites location in Donholm and bitumen samples for penetration grade 80/100, were purchased from Colas East Africa in Nairobi County. The results obtained in this study showed that penetration of bituminous binders reduced from 88 to 41 tenths of a mm at 20 % rubber content. This implied that modified binders became more harder with addition of rubber as a modifier and can withstand fluctuating temperatures of asphalt pavements. Softening point, a candidate also crucial for pavement temperature susceptibility, increased from 48.8oC to 63.9oC at 20 % waste rubber content. This showed that the modified binders can withstand the elevated temperatures of asphalt pavement surfaces. The flashpoint and specific gravity of the neat and rubber-modified binders did not significantly because tire rubber is not very flammable and is of almost same specific gravity as bitumen of 1.1g/cc. Viscosity at 135oC increased from 304.3cSt to 330.7cSt at a waste rubber content of 12% and became unworkable at rubber content beyond 12% when determined using the standard reverse flow viscometers method. Ductility at 25oC reduced from 135.5cm to 48.3cm as 3% to 20% waste tire rubber was added, implying that the rubber makes bituminous binders stiffer. Solubility decreased from 99.6% to 98.3% when 20% of rubber was added implying that addition of more rubber increased impurities in the bitumen. The loss on heating due to aging increased from 0.2% to 0.4% at 12% rubber content and further increased to 1.2% at 20% waste tire rubber content. This showed that the quantity of volatiles increased with addition of more waste tire rubber.

Penetration and perforation characteristics of the novel UHMWPE film laminates by the 7.62 mm standard bullet

Penetration and perforation characteristics of the novel UHMWPE film laminates by the 7.62 mm standard bullet

Investigation on a ferrite-based low-density steel composite plate with crossed-laminated structure and its ballistic penetration characteristics

Investigation on a ferrite-based low-density steel composite plate with crossed-laminated structure and its ballistic penetration characteristics

Field testing study on jacked pile penetration characteristics in laminated clay based on FBG sensing technology

In order to analyze the change of static pressure pile characteristics in silt and silty clay with the penetration depth, two PHC pipe piles were penetrated in the field in the actual project, and the research was based on the full section test technology and FBG test technology. The results show that the pile pressure increases with the increase of the pile penetration depth; The change of pile tip resistance is affected by the soil layer hardness; When the pile tip is in the transition stage, the pile tip resistance increases significantly; In the process of pile penetration, the hardness and brittleness of the soil layer will be affected by the pile penetration, and the different soil layers will have different effects on the pile tip resistance of the two piles; When the pile goes deep into the soil, the pile side resistance will change slowly, but it will usually increase. This fluctuation is related to the difference of the soft and hard layers of the soil layer, and will also be subject to performance constraints; The pile end resistance ratio in hard soil will be smaller than that in soft soil, which will further affect the load sharing ratio of the test pile. The test results can provide support for practical engineering technology.

Evaluation of cement grouted bituminous macadam technology: a laboratory study

ABSTRACT Cement Grouted Bituminous Macadam (CGBM) is a composite pavement that can offer sustainability in the pavement construction sector. The main objective of this study emphasises designing and evaluating the CGBM mixes prepared with different cementitious grouts and aggregate gradations. Compressive strength (7 and 28 days), Flexural strength (28 days), Marsh cone flow, and Initial and final setting time were considered for optimising the cementitious grouts. The details of several investigations on CGBM that include Marshall stability, Compressive strength, Indirect Tensile Strength (ITS), Resilient Modulus (Mr), Fracture energy, and Cantabro abrasion test were reported. The experimental results showed that sand and micro silica influence the mobility of grout to a greater extent. Percolation of grouts into Open Graded Friction Course (OGFC) mixes was a critical concern for grouts with flow time longer than 35 s. A reduction in the pore volume and reduced interconnected links in finer gradation resulted in improper full-depth penetration (FDP) characteristics. Mixture level tests for CGBM revealed that Mr of CGBM improved by about 6 times compared to the bituminous mix. In addition, CGBM showed high tensile strength with rapid crack propagation behaviour. Further, pavement design demonstrated a 35% of thickness reduction and cost reduction due to CGBM implementation.

Penetration Characteristics Optimization and Design of Hilly Rural Road

Penetration Characteristics Optimization and Design of Hilly Rural Road

In vivo near-infrared fluorescence and SPECT-CT imaging of colorectal Cancer using the bradykinin B2R-specific ligand icatibant.

Cancer molecular imaging using specific probes designed to identify target proteins in cancer is a powerful tool to guide therapeutic selection, patient management, and follow-up. We demonstrated that icatibant may be used as a targeting probe for the significantly upregulated bradykinin B2R in colorectal cancer (CRC). Icatibant-based probes with high affinity towards bradykinin B2R were identified. The near-infrared (NIR) fluorescent dye conjugate MPA-PEG3-k-Icatibant and radioconjugate [99mTc]Tc-HYNIC-PEG4-Icatibant exhibited favourable selective and specific uptake in tumours when the subcutaneous and orthotopic colorectal tumour-bearing mouse models were imaged using NIR fluorescence imaging and Single-Photon Emission Computed Tomography-Computed Tomography (SPECT-CT), respectively. The tracer of [99mTc]Tc-HYNIC-PEG4-Icatibant accumulated in tumours according to biodistribution studies and peaked at 4h with an uptake value of 3.41±0.27%ID/g in HT29 tumour-bearing nude mice following intravenous injection (i.v.). The tumour-to-colorectal signal ratios were 5.03±0.37, 15.45±0.32, 13.58±1.19 and 11.33±1.73 1, 2, 4 and 6h after tail-veil injection, respectively. Overall, in the wake of rapid and precise tumour delineation and penetration characteristics, icatibant-based probes represent promising high-contrast molecular imaging probes for the detection of bradykinin B2R.

Numerical study of nanoparticle penetration characteristics in forked tubes using tracking particle identification

Numerical study of nanoparticle penetration characteristics in forked tubes using tracking particle identification

Droplet Penetration Model Based on Canopy Porosity for Spraying Applications

Analysing the penetration and droplet deposition characteristics in the canopy of fruit trees is critical for optimising the operational parameters of air-assisted spraying equipment, achieving precise application of chemicals, and improving the effectiveness of fruit tree pest and disease control. We used a mobile LIDAR system to detect the tree canopy characteristics and optical porosity and conduct wind tunnel experiments to investigate the interaction between the tree canopy, the airflow field, and the droplet penetration ratio in the canopy of fruit trees. The results show that the relative wind velocity decreases rapidly during canopy penetration, and that the minimum value occurs at the back of the canopy. The smaller the optical porosity, the greater the reduction in wind velocity is. The quadratic exponential regression model had the highest coefficient of determination (R2) (0.9672) and the lowest root mean square error (RMSE) (5.56%). This paper provides information on optimising the spraying parameters, improving the pesticide utilisation rate, and selecting the optimum spraying conditions and application parameters.

Research on the Penetration Characteristics of PELE Projectile with Reactive Inner Core.

With the improvement of protection technology, the damage power of conventional penetrators has become increasingly inferior. Reactive material is a new type of energetic material, which has strong energy release capabilities under high-velocity-impact conditions. In this paper, the reactive materials were put into the penetrator, and its penetration characteristics were studied. First, the penetrator with enhanced lateral effect (PELE) projectile structure with better penetration capability was obtained by numerical simulation. Then, based on the established polytetrafluoroethylene (PTFE)/Al reactive material reaction model, the numerical simulation and experimental research of the PELE projectile with a reactive inner core penetrating the target were carried out. The results show that the simulation results are in good agreement with the experimental results, which verifies the confidence of the numerical simulation. The PELE projectile had a significant increase in power with the use of a truncated conical head and reactive materials. The residual velocity of the truncated cone PELE projectile increases by 8.41-21% over conventional PELE projectiles. Its damage range is 43% higher than that of conventional penetrators. The simulation method and the conclusions obtained in this paper can provide support and reference for further research on reactive materials and on effectively improving the damage power of the penetrator.

Comparison between the penetration characteristics of methyl bromide and ethanedinitrile through the bark of pine (Pinus radiata D.Don) logs.

Ethanedinitrile (EDN) is a fumigant being commercialized worldwide as an alternative phytosanitary treatment to methyl bromide (MB) for forest products. The penetration characteristics of MB and EDN were measured through the bark of wooden blocks (100 × 100 × 50 mm) cut from the upper (average bark thickness 5 ± 2 mm) and lower (average bark thickness 25 ± 5 mm) trunk of recently felled pine (Pinus radiata D.Don) trees. Doses of 48 g m-3 MB and 50 g m-3 EDN were applied to chambers at 10 and 20°C for 10h. Penetration of MB was influenced by the interaction between fumigation time and temperature, with concentrations increasing at a higher rate at 20°C compared with at 10°C. After 10h, an average concentration of 8.05 ± 0.89 g m-3 had penetrated the bark of log sections at 20°C, whereas 5.20 ± 0.89 g m-3 was measured at 10°C. By contrast, the factors examined in this study did not significantly impact the penetration of EDN. Concentration × time (CT) values for MB under the bark were 35.20 ± 2.30 g h m-3 at 10°C and 55.85 ± 9.58 g h m-3 at 20°C; whereas for EDN, CT values were 19.50 ± 6.80 g h m-3 at 10°C and 19.08 ± 4.10g h m-3 at 20°C. MB can achieve a higher concentration under the bark of log sections during simulated fumigations, but all of the factors examined affected the ability of MB to penetrate the bark of wooden blocks. By comparison, the penetration of EDN through the bark is more consistent than MB under laboratory conditions. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.