Penetration Ratio Research Articles

Low alkali sulpho-aluminate cement encapsulated microbial spores for self-healing cement-based materials

Microbial self-healing cement-based materials have developed into a novel technology in recent years. It has the promising potential to improve self-healing capacity of cracks by microbial induced calcium carbonate precipitation (MICP). In this paper, low alkali sulpho-aluminate cement (SC) was used as the carrier to protect spores from the high alkalinity environment inside the cement-based materials. The protective effect of SC on spores was studied in the simulated pore solution of cement-based materials, and then area repair ratio, recovery ratio of water permeability, repair ratio of anti-chloride ion penetration and healing depth were used to evaluate the self-healing efficiency of cracks. Moreover, the precipitates formed at the crack mouth of specimens were analyzed by XRD and SEM equipped with an EDS. The results showed that sulpho-aluminate cement had an excellent protective effect for spores and the addition of microbial self-healing agent would slightly affect the early mechanical properties of cement-based materials, but could improve them in later ages. In addition, the cracks of microbial group with a width of 0.25 - 0.35 mm were completely filled by CaCO3, the area repair ratio, recovery ratio of water permeability and repair ratio of anti-chloride ion penetration were 99.2%, 97% and 63.2%, respectively. Meanwhile, the average healing depth of cracks was 2895 μm, which had not been reported in self-healing cement-based materials researches.

Filtration performance of glass fibrous air filter media under sinusoidal flow condition

Air filter is one of the key equipments for sustainable built environment. However, the variation of incoming air velocity is usually neglected in previous studies. Therefore, we applied computational fluid dynamics techniques at micro-scale to study the filtration performance of a glass fibrous media under sinusoidal flow condition. The effects of different flow rates, fluctuation frequencies, fluctuation amplitudes and particle sizes on filtration performance were investigated. Results show that changing the incoming flow field can weaken the Brownian diffusion of particles, resulting in reduced capture efficiency for particles smaller than 0.1 μm. The ratio of particle penetration between sinusoidal flow condition and constant flow condition is calculated. When the fluctuating frequency of the airflow changes for particles less than 0.1 μm, the smaller the particle size is, the larger the ratio of particle penetration is. When the particle size is near the Most Penetrating Particle Size (MPPS), the fluctuating airflow with large amplitude makes the particles more easily trapped by the fiber. The fluctuating airflow with large amplitude will result in a significant reduction in the capture efficiency for particles larger than 1 μm, and the penetration ratio will be greater than that under constant flow condition by three times. For particles with size smaller than 0.1 μm and larger than 1 μm, the amplitude of 0.4 u‾ and smaller has little effect on the capture efficiency. The capture efficiency of particles with size near MPPS value is less susceptible to changes in sinusoidal gas velocity with small amplitude.

Efficacy, pharmacokinetics and neurocognitive performance of dual, NRTI-sparing antiretroviral therapy in acute HIV-infection.

The aim of this study was to evaluate penetration of antiretrovirals into compartments and efficacy of a dual, NRTI-sparing regimen in acute HIV infection (AHI). Single-arm, open-label pilot study of participants with AHI initiating ritonavir-boosted darunavir 800 mg once daily and etravirine 400 mg once daily or 200 mg twice daily within 30 days of AHI diagnosis. Efficacy was defined as HIV RNA less than 200 copies/ml by week 24. Optional sub-studies included pharmacokinetics analysis from genital fluids (weeks 0-4, 12, 48), cerebrospinal fluid (CSF) (weeks 2-4, 24 and 48) and endoscopic biopsies (weeks 4-12 and 36-48). Neuropsychological performance was assessed at weeks 0, 24 and 48. Fifteen AHI participants were enrolled. Twelve (80%) participants achieved HIV RNA less than 200 copies/ml by week 24. Among 12 participants retained through week 48, nine (75%) remained suppressed to less than 50 copies/ml. The median time from ART initiation to suppression less than 200 and less than 50 copies/ml was 59 and 86 days, respectively. The penetration ratios for etravirine and darunavir in gut associated lymphoid tissue were 19.2 and 3.05, respectively. Most AHI participants achieving viral suppression experienced neurocognitive improvement. Of the three participants without overall improvement in neurocognitive functioning as measured by impairment ratings (more than two tests below 1 SD), two had virologic failure. NRTI-sparing ART started during AHI resulted in rapid viral suppression similar to NRTI-based regimens. More novel and compact two-drug treatments for AHI should be considered. Early institution of ART during AHI appears to improve overall neurocognitive function and may reduce the risk of subsequent neurocognitive impairment. CLINICALTRIALS.GOV:: NCT00855413.

Drained triaxial response of clay reinforced with sand columns

In ground-improvement applications involving stone columns in soft clays, the columns act as drains that facilitate partial drainage during practical load applications. Partial drainage could improve the short-term strength of the clay/column composite. The objective of this work was to bracket the range of loading conditions by investigating the fully drained response of clay/column composites through consolidated drained triaxial tests. The area replacement ratio, the column penetration ratio and the presence of geotextile encasement were varied in the testing programme. A maximum improvement of 69% was observed in the deviatoric stress for area replacement ratios of 31·7%. A comparison between identical drained and undrained tests indicated that the deviatoric stresses were higher in drained tests with the drained response representing an upper bound for the strength of the reinforced clay specimens. When the improvements observed in triaxial tests were compared with improvements witnessed in full-scale footing tests, the triaxial test results seemed to over predict the per cent improvement observed in the field bearing capacity.

Unsteady flow to a partially penetrating pumping well with wellbore storage in a dual-permeability confined aquifer

In this article, a new model is presented for imparting unsteady flow to a partially penetrating pumping well with wellbore storage placed in double-permeability confined aquifers to investigate the wellbore drawdown transient behavior. In this model, both the fracture and matrix systems are connected directly with the wellbore as flow pathways, while comprehensively considering the crossflow between the matrix and the fractures. The top and bottom boundaries are assumed to be impermeable, and the outer side boundaries could be infinite. Subsequently, Laplace transformation and finite Fourier cosine transformation are employed to obtain analytical solutions of the dual-permeability flow model in the Laplace domain. The derived analytical solution is general and can be reduced to several other previous results. The numerical inversion algorithm of Stehfest is used to solve the wellbore drawdown in the real time domain. Subsequently, the model is validated by comparing it with previous results. Groundwater flow characteristics are analyzed in detail and divided into five flow stages: wellbore storage flow, early-radial flow, quasi-spherical flow, crossflow between the matrix and the fractures, and quasi-radial flow. The different flow stages show some special values on the drawdown and its derivative log-log plots. There is a hump/dip feature in the semi-logarithmic curve of the drawdown derivative, which are inherent characteristic for dual-permeability flow behavior. The effects of some important parameters of the aquifer or pumping wells on drawdown and its derivative, such as wellbore storage coefficient, penetration ratio, crossflow coefficient, storativity ratio, transmissivity ratio, dimensionless aquifer thickness of anisotropy and skin factor, are analyzed and discussed in detail.

The Impact of Real Exchange Rate on International Trade: Evidence From Panel Structural VAR Model

This paper investigates the importance of real exchange rates on export volumes by estimating a panel SVAR model using quarterly unbalanced panel data from 21 emerging markets over the 2005:Q1-2018:Q4 period. Although the results suggest no conclusive evidence that real exchange rate shocks do affect the export volumes in our sample of emerging markets, the responses of export volume to real exchange rate shocks are heterogeneous across countries in which commodity exporter countries, on average, have a lower response of exports to the real exchange rate movements. Furthermore, we find that while the magnitude of response of the export volumes to exchange rate shocks is positively related to exchange rate volatility, the higher export market penetration ratio helps insulate the economy from real exchange rate shocks. Overall, our results carry broad policy implications indicating that policymakers need to pay attention to the exchange rate volatility of their countries and expand their export competition in the world trade.

Study of Radial Vibration Impact on Friction and Torque of Rotary Drill String

During extended-reach well drilling, the torque of a rotary drill string is too large in the horizontal section, which results in the failure of the drill string. The effect of radial vibration on the friction and torque of the rotary drill string is unclear. In this work, first, the principle of the impact of radial vibration on the friction and torque of the rotary drill string in the horizontal section is analysed. Then, joints with an elliptical outer edge of the section are designed, which can generate low-amplitude vibration as the drill string rotates owing to the interaction with the wellbore wall. The radial vibration characteristics can be tuned by changing the major to minor radius ratio of the ellipse. A self-developed experimental device was designed to test the performance of tools with reduced friction and torque. The drill string torque with different penetration rates, rotation speeds, and ratios of the major radius to minor radius of the ellipse were systematically studied. The experimental results show that the average and the maximum amplitudes of the torque fluctuation first decrease to the lowest value and then increase with the increase of the ratio. When the ratio reaches 1.065, the average and the maximum amplitudes of the torque fluctuation evidently reduce; therefore, a joint with a ratio of 1.065 can effectively reduce frictional torque. The average torque reduces when the penetration rate and rotation speed decrease. At rotation speeds of 45 and 60 r/min, the maximum amplitude of torque fluctuation increases first and then decreases with an increase in penetration rate, and it reaches a maximum value at a penetration rate of 22.5 m/h. The fundamental frequency of torque fluctuation is almost linearly related to rotation speed, which is irrelevant to the penetration rate and the ratio of major to minor radius of the ellipse.

Effect of the chemical structure on the drug release from brinzolamide based nano eye-drops

Commercially available eye-drops scarcely penetrate the eye because of the cornea, which is located at the surface of the eye and function of barrier to keep out foreign matter. To enhance the penetration ratio of eye-drop, we have proposed nanometer-sized eye-drops called “nano eye-drops.” A series of prodrug compounds derived from brinzolamide, a glaucoma therapeutic agent, connected with a trimethyl lock (TML) group were synthesized and the nano eye-drops of the resulting prodrugs were successfully fabricated by the reprecipitation method. We found that the drug release of nano eye-drops critically depended on the chemical structure of the prodrugs comprising the nano eye-drops. As a result, the timing of the ocular hypotensive effect was controlled by altering the chemical structure of brinzolamide prodrug. These results provide insight into drug design for effective controlled release.

Design of a scintillator-based prompt gamma camera for boron-neutron capture therapy: Comparison of SrI2 and GAGG using Monte-Carlo simulation

Boron–neutron capture therapy (BNCT) is a cancer treatment method that exploits the high neutron reactivity of boron. Monitoring the prompt gamma rays (PGs) produced during neutron irradiation is essential for ensuring the accuracy and safety of BNCT. We investigate the imaging of PGs produced by the boron–neutron capture reaction through Monte Carlo simulations of a gamma camera with a SrI2 scintillator and parallel-hole collimator. GAGG scintillator is also used for a comparison. The simulations allow the shapes of the energy spectra, which exhibit a peak at 478 keV, to be determined along with the PG images from a boron–water phantom. It is found that increasing the size of the water phantom results in a greater number of image counts and lower contrast. Additionally, a higher septal penetration ratio results in poorer image quality, and a SrI2 scintillator results in higher image contrast. Thus, we can simulate the BNCT process and obtain an energy spectrum with a reasonable shape, as well as suitable PG images. Both GAGG and SrI2 crystals are suitable for PG imaging during BNCT. However, for higher imaging quality, SrI2 and a collimator with a lower septal penetration ratio should be utilized.

Plasma and cerebrospinal fluid pharmacokinetics of ondansetron in humans.

Changes in serotonergic sensory modulation associated with overexpression of 5-HT3 receptors in the central nervous system (CNS) have been implicated in the pathophysiology of neuropathic pain after peripheral nerve damage. 5-HT3 receptor antagonists such as ondansetron can potentially alleviate neuropathic pain, but have limited effectiveness, due potentially to limited CNS access. However, there is currently limited information on CNS disposition of systemically-administered 5-HT3 receptor antagonists. This study evaluated the cerebrospinal fluid (CSF) disposition of ondansetron, as a surrogate of CNS penetration. Fifteen patients were given a single 16 mg intravenous 15 minute infusion of ondansetron, followed by serial blood and a single CSF sampling. Population pharmacokinetic (PK) modelling was implemented to describe the average and individual plasma and CSF profiles of ondansetron. A two-compartmental model was used to capture ondansetron plasma PK with a single CSF compartment to describe distribution to the CNS. The individual model-estimated CSF to plasma partition coefficients of ondansetron were between 0.09 and 0.20. These values were mirrored in the calculated CSF penetration ratios, ranging from 0.08 to 0.26. After intravenous administration, CSF concentrations of ondansetron were approximately 7-fold lower than those observed in the plasma. A model could be developed to describe individual CSF concentration-time profiles of ondansetron based on a single CSF data point. The low CSF penetration of ondansetron may explain its limited analgesic effectiveness, and affords an opportunity to explore enhancing its CNS penetration for targeting conditions such as neuropathic pain.

The effects of cross-formational water flow on production in coal seam gas reservoir: A case study of Qinshui Basin in China

In coal seam gas (CSG) reservoirs, hydraulic connectivity usually exists between the coal and overlying permeable formation, which results in the delay of the dewatering process and a large volume of produced water. The cross-formational water flow can dramatically influence the production of CSG reservoirs, reduce the economic viability of production and increase the impact on the environment.To assess the cross-formational water flow of a CSG well, this study investigates the effects of cross-formational water flow from the overlying permeable formation on gas production. Simulation models are constructed to represent the water crossflow in four connection scenarios, including contact zone with and without penetrated fracture, and no-contact zone with and without penetrated fracture. The penetration ratio, defined as the ratio of fracture height in permeable formation to the formation thickness, is employed to characterize the extension degree of hydraulic fracture in the overlying formation. The effects of cross-formational water flow on CSG production are analyzed using dimensionless production curves and relative permeability curves calculated from the production history. The field application of this study is demonstrated by the production history of fractured CSG wells in the Qinshui Basin, China.The simulation results show that if the overlying formation is directly connected to the coal seam (contact zone scenario), the hydraulic fracture leads to the decrease of the peak gas production rate with the cumulative water production increasing dramatically. If the overlying formation is connected to the coal seam by hydraulic fractures only (no-contact zone scenario), gas production increases in two stages. Initially, the gas production rate exhibits a slow increase, followed by a fast increase before reaching the peak rate. When the hydraulic fracture penetrates the overlying formation, a 10% increase of the penetration ratio results in 0.55% and 1.82% increase of cumulative water production in the indirect and direct connection scenarios, respectively. In both scenarios, 10% penetration ratio increase leads to 7.41% reduction of gas production rate. The methods and simulation results presented in this work can be used to evaluate the impacts of cross-formational water flow on gas production and identify the cross-formational water flow in CSG wells from production history.

Experimental and numerical investigations on rolling element bearing thermal behaviour

In the present study, some measurements have been conducted on a dedicated test rig to investigate rolling element bearing thermal behaviour. This test rig makes possible the determination of the tested rolling element bearing power losses through the resistive torque measurement. Some thermocouples are located on fixed parts of the system (housing, rolling element bearing outer ring) and others on rotating parts (rolling element bearing inner ring and shaft) via a telemetry system. A deep groove ball bearing, whose pitch diameter is equal to 85 mm, has been tested under oil jet lubrication for different operating conditions. Measurements of the penetration ratio, defined as the proportion of oil actually entering the rolling element bearing versus the oil injected, have also been conducted. An extended thermal network of the test rig has been established to enable a closer understanding of the rolling element bearing inner thermal behaviour. Based upon the first principle of thermodynamics for transient conditions, the studied system is divided into lumped elements at uniform temperature connected by thermal resistances which account for conduction, radiation and convection. Convection within the rolling element bearing depends on the amount of oil in the oil–air mixture known as the volume fraction. At specific test conditions, the developed model found good agreements with experiences for a given oil volume fraction of 15%. This value of volume fraction leads to an adapted formula for volume fraction in the case of jet lubrication which includes the measured penetration ratio.

Grid Inertia Support Enabled by Smart Loads

The increasing penetration of renewable energy resources (RESs) leads to a continuous displacement of synchronous generators. Since the grid integration of RESs is usually achieved through inertialess power converters, the system inertia reduces and the power system frequency stability is compromised. Consequently, unexpected generator tripping, load shedding, and even blackouts may occur and pose a great threat to the system normal operation. In view of these challenges, this article explores the possibility of providing the inertia support from power-electronics interfaced smart loads. Specifically, a transformerless electric spring topology and the associated control strategy have been developed to provide a substantial inertia support from the noncritical load. As compared with existing inertia enhancement techniques, the proposed solution is cost-effective without the need of additional energy storage units. The smart load inertia provision capability is quantitatively analyzed and experimentally verified on a laboratory-scale test. In the testing results, 40% and 18% reductions of the rate of change of frequency and the maximum frequency deviation are, respectively, observed with a 12% smart load penetration ratio.

Collaborative Planning for Electricity Distribution Network and Transportation System Considering Hydrogen Fuel Cell Vehicles

Under the pressure of climate change, the transportation sector is under electrification, and electric vehicles (EVs) are encouraged to reduce their reliance on fossil fuels. However, in those regions where coal is a dominating power generation fuel source, different opinions about whether EVs can help emission reduction exist. In other words, whether EVs can help emission reduction depends on the energy system configuration and the power generation mix. To achieve the overall emission reduction in both systems, a collaborative planning strategy for electricity and transportation systems is proposed. In the electricity distribution network, the renewable energy source is planned to cope with future demand growth due to the increasing use of EVs. In the transportation network, hydrogen fuel cell vehicles (FCVs) are introduced to realize the coordinated development of different types of vehicles. The location of the hydrogen refueling stations can be planned, and the penetration ratio of internal combustion vehicles, EVs, and FCVs is optimized. The proposed planning model is verified on the 46-bus electricity distribution network and the 21-bus transportation network. The mixed-integer linear programming (MILP) and subgradient methods are employed to solve the proposed optimization model. According to the simulation results, the proposed model can achieve the lowest emission since the electricity and transportation systems can cooperate well.

Material Flow Behavior on Weld Pool Surface in Plasma Arc Welding Process Considering Dominant Driving Forces

In this study, the effect of oxygen in the shielding gas on the material flow behavior of the weld pool surface was discussed to clarify the dominant driving weld pool force in keyhole plasma arc welding (KPAW). To address this issue, the convection flow on the top surface of weld pool was observed using a high-speed video camera. The temperature distribution on the surface along keyhole wall was measured using the two-color pyrometry method to confirm the Marangoni force activity on the weld pool. The results show that the inclination angle of the keyhole wall (keyhole shape) increased especially near the top surface due to the decrease in the surface tension of weld pool through surface oxidation when a shielding gas of Ar + 0.5% O2 was used. Due to the change in the keyhole shape, the upward and backward shear force compositions created a large inclination angle at the top surface of the keyhole. From the temperature measurement results, the Marangoni force was found to alter the direction when 0.5% O2 was mixed with the shielding gas. The shear force was found to be the strongest force among the four driving forces. The buoyant force and Lorentz force were very weak. The Marangoni force was stronger than the Lorentz force but was weaker than shear force. The interaction of shear force and Marangoni force controlled the behavior and speed of material flow on the weld pool surface. A strong upward and backward flow was observed in the case of mixture shielding gas, whereas a weak upward flow was observed for pure Ar. The heat transportation due to the weld pool convection significantly changed when only a small amount of oxygen was admixed in the shielding gas. The results can be applied to control the penetration ratio in KPAW.

Assessment and Mitigation of Electric Vehicle Charging Demand Impact to Transformer Aging for an Apartment Complex

Due to the increasing use of Electric Vehicles (EVs), the effect of the EV charging power demand on the reliability of the power system infrastructure needs to be addressed. In apartment complexes, which have emerged as a common residential type in metropolitan areas and highly populated districts, high charging demand could result in substantial stress to distribution networks. In this work, the effect of EV charging power demand in an apartment complex on the aging of the Distribution Transformer (DT) is studied. A methodology based on the stochastic characterization of vehicle usage profiles and user charging patterns is developed to obtain realistic EV charging demand profiles. Based on the modeled EV charging profile and the transformer thermal model, the effect of different EV penetration ratios on DT aging for an apartment complex in the Republic of Korea is studied. Results for an EV penetration ratio of up to 30% indicated that DT aging could be accelerated by up to 40%, compared to the case without EV charging. To mitigate this accelerated DT aging caused by EV charging, the effectiveness of two integration approaches of Photovoltaic (PV) sources was studied. Based on a case study that included a realistic PV generation profile, it was demonstrated that a significant contribution to DT reliability could be achieved via the operation of PV sources. A more apparent contribution of PV integration was observed with an energy storage installation at higher EV penetration ratios. At an EV penetration ratio of 30%, a maximum decrease of 41.8% in the loss-of-life probability of the DT was achieved. The effects of different PV integration approaches and power management details on DT aging were also studied. The results demonstrate that the EV charging demand could introduce a significant level of stress to DTs and that this impact can be effectively mitigated by installing PV sources. These observations are expected to contribute toward the effective planning of power system infrastructures that support the design of sustainable cities with the widespread use of EVs.

Analysis of Rayleigh–Taylor instability at high Atwood numbers using fully implicit, non-dissipative, energy-conserving large eddy simulation algorithm

Large eddy simulation of three-dimensional, multi-mode Rayleigh–Taylor instability at high Atwood numbers is performed using a recently developed, kinetic energy-conserving, non-dissipative, fully implicit, finite volume algorithm. The algorithm was especially designed for simulating low-Mach number, variable density/viscosity, transitional, and turbulent flows. No interface capturing mechanism is required. Buoyancy and heat transfer effects can be handled without relying on the Boussinesq assumption. Because of this feature, unlike the pure incompressible ones, it does not suffer from the loss of physical accuracy at high Atwood and Rayleigh numbers. In this study, the mixing phenomenon in Rayleigh–Taylor instability and the effects of high Atwood numbers on the development of the flow are investigated using various diagnostics such as local mole fractions, bubble and spike penetration lengths and growth rates, mixing efficiencies, Taylor micro-scales, and corresponding Reynolds numbers and energy ratios. Additionally, some important terms of the Reynolds stress transport equation are also introduced, such as Reynolds stresses (and their anisotropies) and turbulent production. Results show that Rayleigh–Taylor instability at high Atwood numbers is characterized by rapid development of instability due to the increasing growth rates and higher velocities of spike fronts, larger asymmetry in the mixing region, denser interactions in the non-linear phase, and changes in bubble and spike morphologies. It is also found that interactions of spike-fronts with their surroundings are the primary mechanisms of turbulent production and transition to turbulence. However, late time mean flow measures such as energy ratio and mixedness are not significantly affected. A scaling relation between the spike to bubble penetration ratio and the heavy to light density ratio is also provided.

Excretion of Antipsychotics Into the Amniotic Fluid, Umbilical Cord Blood, and Breast Milk: A Systematic Critical Review and Combined Analysis.

Antipsychotics are being increasingly prescribed during pregnancy and in the postpartum period. However, knowledge regarding the ability of antipsychotics to enter the fetal, newborn, and infant circulation presents inconsistencies. Evidence for penetration ratios in an array of matrices will contribute to further studies examining the mechanistic pathway from antipsychotic use to adverse events. A systematic literature search of PubMed and EMBASE was performed to identify studies assessing the concentrations of antipsychotics in maternal blood (serum or plasma), amniotic fluid, umbilical cord blood, and/or breast milk. The penetration ratios were estimated by dividing the antipsychotic concentrations in the target matrix (ie, amniotic fluid, umbilical cord blood or breast milk) by the maternal concentration. Data are provided in means with ranges or SD depending on data availability. Forty-nine eligible studies were identified. For amniotic fluid, the penetration ratios were estimated for quetiapine, clozapine, and flupentixol, with quetiapine displaying the highest ratio (mean 0.59, range 0.09-1.70 versus 0.56, range 0.31-0.82 for clozapine and 0.24, range 0.23-0.24 for flupentixol). For umbilical cord blood, olanzapine had the highest ratio (mean 0.71 ± 0.42) followed by haloperidol (mean 0.66 ± 0.40) and paliperidone (mean 0.53, range 0.50-0.58). In case of breast milk, the highest ratio was observed for amisulpride (mean 14.42, range 11.86-19.50) followed by clozapine (mean 3.19, range 2.79-4.32) and haloperidol (mean 3.11, range 0.59-6.67). The ability of antipsychotics to enter the fetal, newborn, and infant circulation varies considerably among antipsychotics. Given sampling constraints of other matrices, measuring antipsychotic concentrations in maternal blood may represent the least expensive, most readily available, and reliable estimate of fetal/infant exposure.

Multi-layered two stage fibrous composites against low-velocity falling mass and projectile impact

The Multi-layer Two Stage Fibrous Composite (MTSFC) is an innovative type of composite that has gained popularity in recent years and pulled the attention of researchers on global level. The process of preparation composes the subsequent two key actions; first, the natural coarse aggregate skeleton is formed by piling the coarse aggregates and fibres in a particular way; second, the artificially formed skeleton is fully filled with cement grout by gravity method. In the present study, the effect of Glass Fibre Mesh (GFM) insertion on MTSFC is researched by subjecting to falling mass and projectile impacts. Totally, twenty one mixtures with insertion of GFM of varied diameters and with different layout in between the layers are designed and tested under falling mass and projectile impacts. Additionally, the hooked end fibre at a dosage of 2.5% volume of composite was constantly used for all designed mixtures. The purpose of inserting glass fibre mesh in between the top-middle and middle-bottom layer is to play a role of trapping layer in order to prevent/delay the crack propagation. The multiple number of hits to provoke crack initiation and crack ultimate, impact energy at crack initiation and crack ultimate, impact ductility index, front damage area, bottom damage area, damage ratio, depth of penetration and damage pattern are studied hereby. The findings revealed that the GFM reinforcement stratagem combined with steel fibres in MTSFC, turned out to deliver high resistance against impact load and extends the failure duration by absorbing more energy. Also, findings indicated that the depth of penetration, damage area and damage ratio were raised with the number of hits and were lessened by the high content steel fibres together with GFM and coarse aggregate. Consequently, the effect of GFM insertion is minimal when it is placed inbetween top-middle layer. Preferably, it is best to insert GFM inbetween mid-bottom layer in the MTSFC, which extends to delay the crack proliferation while tensile stress are being transformed and offers more impact energy absorbance. The research outcomes obtained from this study is to deliver a baseline information for continuing a deeper research work on MTSFC under impact.

Capillary pressure and saturation of pore-controlled granules for powder bed binder jetting

Powder bed binder jetting (PBBJ) is an additive manufacturing process in which a liquid binder is selectively deposited onto a powder bed to join the powder particles. These deposited parts, called the “green body,” are shaped by ink-jetting a liquid binder onto the powder bed. For liquid binders to be fully cured in the intended area of the powder bed, interaction between the droplets of the liquid binder and layered powder bed is important. This interaction leads to spreading of the binder (lateral migration) and infiltration (vertical migration) in the powder bed; however, it can be adjusted for geometrical accuracy of green body. This study confirms that saturation and penetration depth of the binder in the powder bed is related to the capillary pressure at initial saturation. The capillary pressure differs based on the amount of pores on the surface of dry powder particles. The powders in this study were prepared as granules produced by a spray dryer process with sintering. The different initial saturation capillary pressures of the prepared dry powders were compared with the penetration ratios by comparing the penetration depth and spread diameter. The results confirmed that the penetration ratio was determined by the capillary pressure.