Powder Charge Research Articles

Characteristics of powder charging behavior via forced triboelectric charging on an inclined chute

Characteristics of powder charging behavior via forced triboelectric charging on an inclined chute

Efficient Removal of Brilliant Cresyl Blue from Solution Using Inula Racemosa: Experimental Insights, DFT Modeling, and Docking Simulation

AbstractThis study examined the efficacy of Inula Racemosa leaves in the adsorption of Brilliant Cresyl Blue (BCB) from aqueous solutions. The study uses both experimental and theoretical research, including Density Functional Theory (DFT), to gain a better understanding of how the adsorbent and Brilliant Cresyl Blue molecules interact with each other. We determined the point zero value of the charged powder of Inula Racemosa and characterized the functional groups using FTIR spectroscopy. The experimental results indicate a significant ability of our adsorbent to adsorb the cationic dye Brilliant Cresyl Blue, and we have identified optimal conditions for its effective removal. The results suggest that the most effective amount of our biosorbent was 0.1 g. The equilibrium period for biosorption was 10 min, and the biosorbent capacity for biosorption improved with increasing pH. The Pseudo‐second‐order model accurately predicts the retention of Brilliant Cresyl Blue using Inula Racemosa. The Freundlich model was found to be better suitable for analyzing the isotherm data, revealing a maximum adsorption capacity of 3.49 mg g−1, achieving an efficiency removal of 89.95 %. We compared Density Functional Theory (DFT) calculations with experimental observations to validate the theoretical predictions and improve our understanding of the adsorption mechanism. Docking simulations show how the molecules of Inula Racemosa and Brilliant Cresyl Blue interact with each other, including the interactions of hydrogen bonds and electrostatic forces.

Locally Synthesized Zwitterionic Surfactants as EOR Chemicals in Sandstone and Carbonate.

Zwitterionic surfactants are found to be highly effective in reducing the IFT and changing the wettability. This work studied the solubility and wettability alteration performance of locally synthesized zwitterionic surfactants in Berea sandstone and Indiana limestone. Contact angle measurements were conducted to study the wettability under different conditions. SEM images and TGA results were combined to reflect on the wettability alteration mechanism. The zeta potential test was adopted to study the surface charge of the Indian limestone powder. Results showed that five of the six surfactants dissolved in deionized water to form 1.0 wt % solution, indicating efficient solubility for EOR purposes. Although its wettability alteration performance on oil-aged Berea sandstone is weak to moderate, the performance of ZW6 on Indiana limestone is excellent. ZW6 can change the strongly oil-wet (162°) rock back to water-wet (62.9°) conditions. Increasing its concentration from 0.01 to 0.5 wt % continuously enhanced the performance. The addition of NaCl to 150000 ppm did not affect the wettability alteration. However, the addition of CaCl2 largely suppressed the wettability alteration, while Na2SO4 and MgCl2 both enhanced the performance. With the same headgroup, a more hydrophobic tail group impairs the wettability alteration. The quite different wettability alteration performance of MgCl2 and CaCl2 cases (which had approximately the same amount of calcite dissolution), and the comparable wettability alteration performance of Na2SO4 and MgCl2 (which had very different calcite dissolution amounts) indicate that calcite dissolution is unrelated to wettability alteration.

Influence of blasting charge distribution on the energy required for communition of rock

The most energy-intensive process in the mining industry is particle size reduction - comminution. The first phase of this process is blasting to fragment the rock from the initial Boussinesq's half-space size. Scientific literature demonstrates that the output of a blast in terms of fragment size distribution can be manipulated by varying the specific charge (powder factor) and charge distribution. This study focuses on the influence of blasting on the internal resistance of the blasted fragments; in particular the influence of the spatial distribution of charges. Small-scale blasts were performed on 14 marble blocks using different powder factors and charge distributions. Three control blocks were fragmented by mechanical means for comparison. The results show the correlations between charge distributions and the specific energy of mechanical comminution. Opportunities for adjusting charge diameter and distribution in opencast blasts to improve the performancet of comminution circuits are discussed.

Unmasking hidden ignition sources: A new approach to finding extreme charge peaks in powder processing

Powders acquire a high electrostatic charge during transport and processing. Consequently, in the aftermath of dust explosions, electrostatic discharge is often suspected to be the ignition source. However, definite proof is usually lacking since the rise of electrostatic charge cannot be seen or smelled, and the explosion destroys valuable evidence. Moreover, conventional methods to measure the bulk charge of powder flows, such as the Faraday pail, provide only the aggregate charge for the entire particle ensemble. Our simulations show that, depending on the flow conditions, contacts between particles lead to bipolar charging. Bipolar charged powder remains overall neutral; thus, a Faraday pail detects no danger, even though individual particles are highly charged. To address this gap, we have developed a machine learning-enhanced measurement technology to resolve the powder charge spatially. The first measurements have revealed a critical discovery: a localized charge peak near the inner wall of the conveying duct that is 85 times higher than the average charge that would be measured by the Faraday pail. This finding underscores the possibility of extremely high local charges that can serve as ignition sources, even though they remain undetected by conventional measurement systems. Our new technology offers a solution by spatially resolving the charge distribution within powder flows, unmasking hidden ignition sources, and preventing catastrophic incidents in the industry.

Photochargeable Mn-Based Metal-Organic Framework and Decoupled Photocatalysis.

Designing multifunctional materials that mimic the light-dark decoupling of natural photosynthesis is a key challenge in the field of energy conversion. Herein, we introduce MnBr-253, a precious metal-free metal-organic framework (MOF) built on Al nodes, bipyridine linkers and MnBr(CO)3(bipyridine) complexes. Upon irradiation, MnBr-253 colloids demonstrate an electron photocharging capacity of ~42 C ⋅ g-1 MOF, with state-of-the-art photocharging rate (1.28 C ⋅ s-1 ⋅ g-1 MOF) and incident photon-to-electron conversion efficiency of ~9.4 % at 450 nm. Spectroscopic and computational studies support effective electron accumulation at the Mn complex while high porosity and Mn loading account for the notable electron storage performance. The charged MnBr-253 powders were successfully applied for hydrogen evolution under dark conditions thus emulating the light-decoupled reactivity of photosynthesis.

Fully Consolidated Deposits from Oxide Dispersion Strengthened and Silicon Steel Powders via Friction Surfacing

Abstract The objective of this work is to study the ability of friction surfacing to deposit metal alloys that are difficult to process with traditional methods. Creep and neutron irradiation resistant oxide dispersion strengthened (ODS) materials cannot be produced via conventional casting route due to insolubility of the oxidic and metallic alloy constituents, causing unintended inhomogeneous oxide dispersion and material behavior. Increasing silicon content of Iron-Silicon (Fe-Si) improves electromagnetic properties but embrittles the material significantly and the fusion based manufacturing methods unable to process this steel. The solid-state nature of the friction surfacing process offers a potential alternative processing route to enable wider usage of difficult to process alloy systems. Both ODS and Fe-Si materials are available in powder forms. While the existing literature in friction surfacing focuses on depositing composites by incorporating small quantities powders through holes in consumable rod, this is a first study that shows a large charge of powder can be converted to a homogeneous fully consolidated deposit in friction surfacing. A novel methodology is used that incorporates the high portion of powder feedstock into hollow consumable friction surfacing rods (up to 35% volume fraction). It was found that fully consolidated deposits can be produced with powder feedstocks using proposed methodology. A recrystallized, homogeneous, equiaxed microstructure was observed in Fe-Si 6.8 wt% and a new generation FeAlOY ODS alloy deposits processed with hollow stainless-steel friction surfacing rods. Both powder and rod material plasticize and deposit without bulk intermixing.

Colorimetry method for nitrocellulose powder charge monitoring system

Nitrocellulose powders are unstable chemical compounds. Over time, the consumer properties of the powder charge can change so much that the charges will not only be unsuitable for their intended use, but also become dangerous for personnel and the barrel system. This is associated with the problem of establishing the terms of safe storage of powders and their operational suitability, the need for a constant system for monitoring their condition. However, in developed NATO countries, there is practically no system for monitoring powder charges throughout their entire shelf life. Some countries have some components of the above-mentioned system, but its elements do not fully cover the entire spectrum of the state of powder charges. For the monitoring system to work effectively, informative indicators are needed that allow determining the state of powder charges without the use of complex diagnostic equipment. One of such indicators is the color of the surface of the powder element. In this study, an automated method for assessing the quality of nitrocellulose powder charges by the color of their surface for further use as intended was developed. The use of this method will significantly reduce the time of assessment and decision-making by experts, and eliminate subjectivity. In addition, the method will allow creating a database of powder charges for further monitoring of their condition throughout the entire life cycle. To confirm the reliability and adequacy of the developed method, an experimental study was conducted. The study data showed that the proposed hypothesis is true, namely, during storage, nitrocellulose powder charges change the color of their surface, and it is possible to determine their shelf life

Electrostatic Surface Charging by Water Dewetting.

Water dewetting generates static electricity. We reviewed historical experiments of this phenomenon, and we studied the charging of polymer slides and metal electrode supported polymer films withdrawn vertically from a pool of aqueous solutions. For pure water, charging was negative and surface charge densities increased with the speed of dewetting, which we explain by the thermally activated entrainment of nanometer-sized water droplets or clusters charged by unbalanced adsorbed electric double-layer ions. Surface charge densities increased for reduced polymer film thickness following a power law, which we explain by reduced discharge of the entrained water volumes. At low salinity c ≲ 10 μM, charging was proportional to electrokinetic interfacial charge densities: the negative charging was increased for alkaline solutions and for most salts at μM concentrations and the charge polarity was inversed to positive for a cationic surfactant, a salt with a highly positively charged cation, and for a strong acid at approximately pH 4. Charging was reduced again for c ≳ 100 μM, especially at high dewetting speeds and for chaotropic ions, which we explain by the entrainment of larger and more discharged droplets. We determined adsorption energies of the charged water clusters on the dewetted surface from thermally stimulated discharge of the charged polymer slides and we show that the surface charge distribution, imaged by charged toner powders and measured microscopically by Kelvin probe force microscopy, is a record of the dewetting process that provides spatial and kinetic information about the three-phase contact line motion.

EXPEDIENT REGENERATION PERIODS FOR NITROCELLULOSE POWDER CHARGES WITH LONG SHELF LIFE AND THE DURATION OF THE POST- REGENERATION PERIOD OF THEIR LIFE CYCLE

Currently, a problem in many countries of the world is the presence in arsenals, bases and warehouses of a large number of various ammunition that are beyond the guaranteed storage period. The lack of ammunition production capacity in Ukraine has led to the fact that currently there are ammunition in use whose storage time exceeds 30 years. An analysis of the research showed that after 25 years of storage, due to changes in the energy characteristics of the powder charge, changes occur in the ballistic characteristics of the weapon, which cannot be corrected by introducing amendments to the firing settings. The question arises about the advisability of using such ammunition, both in accurately performing fire missions and operating weapons in general, and in the field of personnel safety. The complex problem of assessing the state of charges is shown, associated with the lack in the state of a reliable system for monitoring the state of powder charges of ammunition, the development of technology for their regeneration, disposal and the possibility of using it for its intended purpose. The first of these problems is key, since the further extension of the life cycle of ammunition depends on its results. Experimental studies have confirmed that changes in the chemical composition of nitrocellulose powders are observed during long-term storage. The change in color of the powder elements confirms the chemical reactions occurring in them with a gradual decrease in their mass. It is presented that during the regeneration process the mass of the powder charge increases by 3 % by saturating the nitrocellulose with hydrogen. The priority time frames for when regeneration gives the maximum effect are graph- ically shown. Analyzing the results of the study, using the ammunition operation model, it was proposed for the first time to use a period after regeneration in the life cycle of powder charges, which makes it possible to determine the time of expedient restoration of the characteristics of gunpowder. It will fluctuate a little for different batches of gunpowder, but, with reasonable probability, its time frame can be determined at 25–27 years. It is predicted that it will be possible to technologically increase the effect of regeneration to 5 %. This will correspond to the restoration of properties to the level of guaranteed operation and a further extension of the operation of the gunpowder by 2 times.

Enhanced Zinc–Air Batteries through the Fabrication of Structured Zinc Electrodes Using Freeze‐Casting

Ice‐templating, a versatile manufacturing process, is widely utilized to create porous materials by freezing aqueous solutions. Notably, this technique is material independent, allowing for the fabrication of microstructured bulk or sheet materials of ceramic, glass, metal, polymer, and composite materials. Herein, the influence of freeze‐cast zinc electrodes on zinc–air batteries is investigated. The analysis includes the charge and discharge cycling behavior of pure powder, gel matrix, and sintered freeze‐cast zinc electrodes, complemented by the study of the distribution of relaxation times. Remarkably, the best cycling performance is achieved with the combination of a gel electrolyte and a freeze‐cast zinc electrode, highlighting the potential significance of this microstructure–electrolyte pairing for enhancing the performance of zinc–air batteries.

ДОСЛІДЖЕННЯ ПРОДУКТІВ ПОСТРІЛУ З ВИКОРИСТАННЯМ РЕНТГЕНОФЛУОРЕСЦЕНТНОГО АНАЛІЗУ

Detection and research of gunshot products using modern devices and research methods is an urgent scientific and practical task. In the literary sources, it is proposed to use X-ray fluorescence analysis, electron microscopy, and optical emission spectroscopy in forensics both to study the product of the shot and to determine the composition of gunpowder and other elements of the charge. The aim of the presented work was to establish the dependence of the nature of the shot products on the composition of the charge elements and the distance to the target using X-ray fluorescence analysis. The composition of the charge elements should be understood as the chemical composition of the powder charge, capsule charge, casing material and the material of the bullet or its shell. As a result of the use of X-ray fluorescence analysis to establish the dependence of the nature of the shot products on the composition of the charge elements and the distance to the target, processing and analysis of the obtained results, a number of conclusions can be drawn. The Elvax Pro device for X-ray fluorescence analysis can be used to study the products of the shot and establish the regularity of the distribution of elements depending on the distance. Studies have shown that the composition of the shot products practically does not depend on the composition of the powder charge, which is explained by the small concentration of modifying elements that are in the organic matrix, but it depends on the capsule charge and the material of the surface of the bullet that was used for the shot. The established dependence of the distribution of the radiation intensities of the elements that are part of the shot products on the distance makes it possible to establish the distance from the weapon to the target. The best marker for determining the distance to the target using X-ray fluorescence analysis due to its sufficiently high content in the shot products is lead

ДОСЛІДЖЕННЯ ПРОДУКТІВ ПОСТРІЛУ З ВИКОРИСТАННЯМ РЕНТГЕНОФЛУОРЕСЦЕНТНОГО АНАЛІЗУ

Detection and research of gunshot products using modern devices and research methods is an urgent scientific and practical task. In the literary sources, it is proposed to use X-ray fluorescence analysis, electron microscopy, and optical emission spectroscopy in forensics both to study the product of the shot and to determine the composition of gunpowder and other elements of the charge. The aim of the presented work was to establish the dependence of the nature of the shot products on the composition of the charge elements and the distance to the target using X-ray fluorescence analysis. The composition of the charge elements should be understood as the chemical composition of the powder charge, capsule charge, casing material and the material of the bullet or its shell. As a result of the use of X-ray fluorescence analysis to establish the dependence of the nature of the shot products on the composition of the charge elements and the distance to the target, processing and analysis of the obtained results, a number of conclusions can be drawn. The Elvax Pro device for X-ray fluorescence analysis can be used to study the products of the shot and establish the regularity of the distribution of elements depending on the distance. Studies have shown that the composition of the shot products practically does not depend on the composition of the powder charge, which is explained by the small concentration of modifying elements that are in the organic matrix, but it depends on the capsule charge and the material of the surface of the bullet that was used for the shot. The established dependence of the distribution of the radiation intensities of the elements that are part of the shot products on the distance makes it possible to establish the distance from the weapon to the target. The best marker for determining the distance to the target using X-ray fluorescence analysis due to its sufficiently high content in the shot products is lead.

Electrostatic discharge mechanisms and dynamic characteristics of different polarity powders in the Silo

Electrostatic discharge in powder silos poses a significant safety hazard due to the risk of fire or explosion. However, the underlying discharge mechanisms are not fully understood. This study aims to improve the comprehension of electrostatic discharge dynamics and mechanisms by introducing a fluid discharge model for charged powder silos. The model validation is carried out by examining discharge patterns and electric field variations. The investigation of the electrostatic field and potential distribution prior to discharge helps to comprehend the discharge conditions. The discharge modes and evolution laws of different polarity powders are explored to reveal disparities in discharge phenomena. These disparities are further scrutinized in relation to electron density, space charge, electric field, and potential. To elucidate the discharge mechanism, the electric field distortion caused by space charge, electron existence time, and migration law are analyzed. The electrostatic and diffusion effects are the main reasons for the discharge differences.

Gluing blood into adhesive gel by oppositely charged polysaccharide dry powder inspired by fibrin fibers coagulation mediator

Hemostatic powders that adapt to irregularly shaped wounds, allowing for easy application and stable storage, have gained popularity for first-aid hemorrhage control. However, traditional powders often provide weak thrombus support and exhibit limited tissue adhesion, making them susceptible to dislodgment by the bloodstream. Inspired by fibrin fibers coagulation mediator, we have developed a bi-component hemostatic powder composed of positively charged quaternized chitosan (QCS) and negatively charged catechol-modified alginate (Cat-SA). Upon application to the wound, the bi-component powders (QCS/Cat-SA) rapidly absorb plasma and dissolve into chains. These chains interact with each other to form a network, which can effectively bind and entraps clustered red blood cells and platelets, ultimately leading to the creation of a durable and robust thrombus. Significantly, these interconnected polymers adhere to the injury site, offering protection against thrombus disruption caused by the bloodstream. Benefiting from these synthetic properties, QCS/Cat-SA demonstrates superior hemostatic performance compared to commercial hemostatic powders like Celox™ in both arterial injuries and non-compressible liver puncture wounds. Importantly, QCS/Cat-SA exhibits excellent antibacterial activity, cytocompatibility, and hemocompatibility. These advantages of QCS/Cat-SA, including strong blood clotting, wet tissue adherence, antibacterial activity, biosafety, ease of use, and stable storage, make it a promising hemostatic agent for emergency situations.

Non-destructive method for determining the strength of concrete based on immersion and extraction of steel nails

Introduction. The method of concrete strength control based on immersion of a steel dowel into concrete due to the energy of a powder charge has been used since the 60s of the last century. Since the early 2000s, the method has been supplemented by the definition of the dowel pullout force from concrete and the definition of an indirect characteristic in the form of the ratio of the pullout force to the depth of immersion of the dowel.
 
 The object of the present research was a method for determining the strength of concrete based on measuring the depth of immersion and the pulling force of a dowel nail installed in concrete.
 
 Aim: to develop requirements for testing by the proposed method, allowing its use as a non-destructive method for testing the strength of concrete.
 
 Materials and methods. The following research methods are used in this work: analysis of available regulatory documents and technical literature on this issue; collection and analysis of the results of previously conducted research using mathematical statistics methods, development of a research program and assignment of parameters, the value of which must be controlled when performing research; performance of own tests and research; analysis of the obtained results of the performed research using methods of mathematical statistics; analysis of the influence of various factors on the result of research, exclusion of non-influencing factors; development of recommendations for the use of the studied control method.
 
 Results. The limitations for the application of the investigated method and the factors that have the most significant impact on the accuracy of the method are revealed: the power spread of the powder charge, the parameters of the indenter (plugged dowel), the criteria for the quality of the dowel installation; a method for rejecting of low-quality results and processing test results has been developed. The factors that do not have a significant impact on the test results have been identified.
 
 Conclusions. Taking into account the identified limitations, a method has been developed for determining the strength of concrete by the magnitude of the local destruction force of concrete when pulling out a dowel nail immersed in concrete, and proposals have been made for inclusion in the State Standard R "Concretes. Determination of the strength by the depth of immersion of the dowel-nail".

A hydrophilic and negatively charged zinc silicate glass powder for antibacterial and antiviral polypropylene composites

Polypropylene (PP) is one of the widely utilized thermoplastics for ordinary applications, attributed to its excellent mechanical properties and resistance to heat and chemicals. However, during pandemic periods like the COVID-19 outbreak, the lack of antibacterial properties in PP might limit its usage as it does not effectively prevent bacterial adhesion and contamination. Therefore, to expand the applications of PP, it becomes crucial to impart antibacterial activity to make it a safer and more versatile material. Herein, we introduce a novel antimicrobial zinc silicate glass powder (ZS), prepared by incorporating a substantial amount of zinc oxide (35 wt%) into a silica network, as an antimicrobial filler in PP. We demonstrate that ZS significantly affects the overall performance of the PP composites, encompassing thermal properties, mechanical performances, and antimicrobial activities, while maintaining the optical transparency of PP. Notably, incorporating ZS results in a significant increase of hydrophilicity and the negative charge of the composite surface compared to the pristine PP surface, leading to the effective inhibition of microbial adhesion. This study offers valuable insights for developing antimicrobial fillers in PP composites by demonstrating the synergetic role of the physicochemical properties of ZS in imparting remarkable antibacterial activity and biocompatibility to PP.

Polarity switch of PMMA powder transported through a PMMA duct

During pneumatic conveying, powder electrifies rapidly due to the high flow velocities. In our experiments, the particles even charge if the conveying duct is made of the same material, which might be caused by triboelectrification between two asymmetric contact surfaces. Surprisingly, we found the airflow rate to determine the polarity of the overall powder charge. This study investigates the charging of microscale PMMA particles in turbulent flows passing through a square PMMA duct. The particles are spherical and monodisperse. A Faraday at the duct outlet measured the total charge of the particles. At low flow velocities, the particles charged negatively after passing through the duct. However, the powder’s overall charge switched to a positive polarity when increasing the flow velocity.

Suppression and Control of Bipolar Powder Charging by Turbulence.

Current models predict particles of the same material but different sizes to charge bipolar upon contacts; the resulting charge peaks endanger process safety. However, we found wall-bounded turbulence to suppress the powder's electrostatic charging. Aerodynamic forces skew the collision frequency and narrow the charge distribution's bandwidth. Bipolar charging reduces, especially in moderately polydisperse systems of a low Stokes number. Not the smallest but midsized particles charge most negatively. Moreover, turbulence separates charge, producing pockets of high electric potential in low-vorticity regions.

Inhaled dry powder liposomal azithromycin for treatment of chronic lower respiratory tract infection

A dry powder inhaled liposomal azithromycin formulation was developed for the treatment of chronic respiratory diseases such as cystic fibrosis and bronchiectasis. Key properties including liposome size, charge and encapsulation efficiency powder size, shape, glass transition temperature (Tg), water content and in vitro respiratory deposition were determined. Antimicrobial activity against cystic fibrosis (CF) respiratory pathogens was determined by MIC, MBC and biofilm assays. Cytotoxicity and cellular uptake studies were performed using A549 cells. The average liposome size was 105 nm, charge was 55 mV and encapsulation efficiency was 75 %. The mean powder particle size d[v,50] of 4.54 µm and Mass Median Aerodynamic Diameter (MMAD) was 5.23 µm with a mean Tg of 76˚C and water content of 2.1 %. These excellent physicochemical characteristics were maintained over one year. Liposomal loaded azithromycin demonstrated enhanced activity against P. aeruginosa clinical isolates grown in biofilm. The formulation was rapidly delivered into bacterial cells with > 75 % uptake in 1 h. Rapid uptake into A549 cells via a cholesterol-dependent endocytosis pathway with no cytotoxic effects apparent. These data demonstrate that this formulation could offer benefits over current treatment regimens for people with chronic respiratory infection.