Ground Particles Research Articles

Microfacies and Depositional Environments Analyses of the Hartha Formation at Balad Oil Field, Central Iraq

The Hartha Formation (Late Campanian-Maastrichtian) has been recognized as a potential reservoir for hydrocarbons in various oilfields within the Mesopotamian basin in central Iraq. The formation has conformable upper contact with the overlying Shiranish Formation but unconformable lower contact with the underlying Mushorah Formation. This formation has been stratigraphically divided into two main parts. The lower part is particularly significant as it is recognized as an important stratigraphic unit due to the presence of oil shows. Five subsurface sections and many thin sections of the Hartha Formation (Late Campanian-Maastrichtian) were studied to unravel the depositional facies and environments. The sedimentary microfacies of the Hartha Formation in the Balad oil field include mudstone, wackestone, wackestone to packstone, packstone, Packstone to Grainstone, and Rudstone. These depositional microfacies have been subdivided according to their primary and diagenetic constituents into six sub-microfacies. The microfacies have been deposited in deep shelf margin, open shelf, and foreslope of varying salinities and energy levels. Cementation, dolomitization, compaction and pressure solution (stylolitization ), and dissolution are observed affecting variably both ground mass and particles. These diagenetic processes have both positive and negative effects on porosity types, causing fluctuations in porosity levels. The primary pore types identified within the study wells include interparticle porosity, intercrystal porosity, moldic porosity, vuggy porosity, channel porosity, and fracture porosity.

Reconstruction of a Fluid Bed Device for Separating Granular Material from the Grinding Process of Rapid Antigen Tests

The article includes the study and reconstruction of a fluid bed device with the purpose of separating the granular material from the grinding process of rapid antigen tests. The following techniques were performed, with the purpose of characterisation of the ground particles: sieve analysis, X-ray fluorescence spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy and transmission electron microscopy. The paper includes experimental testing of a simplified separation process with zeolite spheres and paper strips, supported by a numerical model. The flow conditions’ impact on the behaviour and interactions of particles of the considered problem were simulated using coupled computational fluid dynamics (CFD) and the discrete element method (DEM) approach. The separation process of zeolite spheres and paper strips was found to be efficient. The simulation results showed the appropriate behaviour of the particles during the process. We explained the results’ deviations, and we also presented the shortcomings and possible improvements. Further research is required to define the adequacy of the process, while using actual ground material of rapid antigen tests.

Fabrication of Novel Pre-Polymerized BisGMA/Silica Nanocomposites: Physio-Mechanical Considerations.

Resin composite mimics tooth tissues both in structure and properties, and thus, they can withstand high biting force and the harsh environmental conditions of the mouth. Various inorganic nano- and micro-fillers are commonly used to enhance these composites' properties. In this study, we adopted a novel approach by using pre-polymerized bisphenol A-glycidyl methacrylate (BisGMA) ground particles (XL-BisGMA) as fillers in a BisGMA/triethylene glycol dimethacrylate (TEGDMA) resin system in combination with SiO2 nanoparticles. The BisGMA/TEGDMA/SiO2 mixture was filled with various concentrations of XL-BisGMA (0, 2.5, 5, and 10 wt.%). The XL-BisGMA added composites were evaluated for viscosity, degree of conversion (DC), microhardness, and thermal properties. The results demonstrated that the addition of a lower concentration of XL-BisGMA particles (2.5 wt.%) significantly reduced (p ≤ 0.05) the complex viscosity from 374.6 (Pa·s) to 170.84. (Pa·s). Similarly, DC was also increased significantly (p ≤ 0.05) by the addition of 2.5 wt.% XL-BisGMA, with the pristine composite showing a DC of (62.19 ± 3.2%) increased to (69.10 ± 3.4%). Moreover, the decomposition temperature has been increased from 410 °C for the pristine composite (BT-SB0) to 450 °C for the composite with 10 wt.% of XL-BisGMA (BT-SB10). The microhardness has also been significantly reduced (p ≤ 0.05) from 47.44 HV for the pristine composite (BT-SB0) to 29.91 HV for the composite with 2.5 wt.% of XL-BisGMA (BT-SB2.5). These results suggest that a XL-BisGMA could be used to a certain percentage as a promising filler in combination with inorganic fillers to enhance the DC and flow properties of the corresponding resin-based dental composites.

From Micro to Nano: Grinding Natural Magnetite Ore for Microalgae Harvesting

Microalgae represent a promising feedstock for sustainable biomass and energy. The low cell concentration after cultivation, however, limits the current application fields. Magnetic microalgae harvesting is a recent approach to overcome the economic limitations of exploiting this natural resource. Accordingly, different particle types have been applied, mainly synthetically produced magnetic nanoparticles, though none on an industrial scale. Particle sizes between a few micrometers and a few nanometers have not been tested. We expected 200–500 nm to be advantageous for harvesting and as a compromise between the highly available surface and good separation properties. However, this intermediate magnetite particle size between the micro- and nano-scale cannot be reached via chemical synthesis. Therefore, we ground natural magnetite ore in a planetary ball mill and an agitator bead mill producing particles in the targeted size range. Applying ore particles ground from ~6 µm to 250 nm yields harvesting efficiencies comparable to synthetically produced nanoparticles (Ø ~ 10 nm), with only half the BET surface. Complete harvesting of saline microalgae Microchloropsis salina is possible with ground particles at alkaline pH. We demonstrate the feasibility of a harvesting process with natural, low-cost, easily separable, and readily available magnetite ore particles as a promising step towards exploiting valuable microalgal products in life sciences.

Grinding Characteristics of New Varieties of Winter Triticale Grain

Triticale (× Triticosecale Wittmack), developed by crossing rye and wheat, is increasingly applied in food production. The aim of this paper was to study the grinding process of eight new triticale grain (TG) varieties harvested in 2020 and 2021. TG was tempered to 12% of moisture and a knife mill was used for the size reduction. The following parameters characterizing the grinding process of TG were determined: specific grinding energy, Sokołowski grinding index, particle size distribution and average particle size. Additionally, the basic chemical composition, total phenolic content and antiradical activity of TG were determined. The protein content of TG was strongly influenced both by the variety and harvesting year, while other components were mostly affected by the genetic factor. The strongest influence on the grinding indices has a variety of TG. Specific grinding energy varied in the range of 14.0 kJ kg−1–17.8 kJ kg−1 and was positively correlated with the size of ground particles. Especially, the grain of Belcanto required lower grinding energy requirements and showed the strongest antioxidant capacity compared with other varieties of TG.

Hammer milling switchgrass from weathered bales

Considering that grasses have been targeted as raw material for bioenergy and will have to be handled in mass flow manner to be efficient, there is need to understand how grasses can be ground into easily flowing particles. For a biorefinery, the biomass will inevitably have to be stored, more than likely in an environment exposed to the elements. Consequently, there is a need to understand how the weathered material will interact with processing equipment like a hammermill. Grinding tests with switchgrass stored for a year in the open (weathered) and undercover (unweathered) were undertaken. The switchgrass was ground in an 18.64 kW hammermill with screen openings 9.52, 31.75, and ∞ mm (no screen). Results from this preliminary evaluation show that both weathered switchgrass (WSG) and unweathered switchgrass (USG) had grinding rates similarly increasing as the screen openings size increased with the unweathered material having a slightly higher throughput. When analyzed as a volume distribution of ground particles in machine vision methodology, switchgrass condition did not affect the particle size distribution parameters of the ground material. However, the geometric mean length for WSG increased from 6 mm to 37 mm with increasing screen size for WSG, whereas the geometric mean length for USG increased but only from 6 mm to 31 mm. While future studies are needed, the results however serve as a reference for preprocess grinding of biomass, either fresh or weathered (common in large-scale storage), for bioenergy/industrial use in obtaining the desired particle size at a given production rate.

Microporous Engelhard titanosilicate based polyamide membrane for water vapor dehumidification with excellent chemical resistance to toluene

Herein, we describe microporous Engelhard titanosilicate-4 (ETS-4) based polyamide membranes for water vapor dehumidification. ETS-4 particles have unique properties such as good water affinity, excellent chemical resistance, and size selective or molecular sieve properties (effective pore diameter of ETS-4: 3–4 Å, kinetic diameter of H2O: 2.65 Å, toluene: 5.85 Å). ETS-4 particles were fabricated by a hydrothermal method and ground to obtain a smaller size. The ground particles were dispersed in diethylenetriamine (DETA) solution, followed by interfacial polymerization with trimesoyl chloride (TMC), resulting in thin film nanocomposite (TFN) membranes. The addition of ETS-4 particles on the outer surface of polysulfone (PSf) hollow fibers resulted in improvement of the hydrophilicity and surface roughness of the membrane. The ETS(0.2) membrane with 0.2 wt% ETS-4 concentration showed the highest selectivity (413) and the highest water vapor permeance (1544 GPU) at 25 °C and relative humidity 60 %. In addition, the toluene removal performance of the best ETS(0.2) membrane was tested and demonstrated a rejection efficiency of ca. 94.7 %. The long term stability of the ETS(0.2) membrane was also measured under toluene gas flow for one month and it was confirmed that the ETS-4 based membrane had excellent chemical stability against toluene.

A Fractal Description of Finely Ground Particles of Natural Quartz Using Particle Size and Image Analyses

A Fractal Description of Finely Ground Particles of Natural Quartz Using Particle Size and Image Analyses

Chemical and Physical Properties of Organic Bedding Materials

Highlights Finely ground particles absorb more water than medium or coarse particles. Corn stover and wheat straw have highest water holding capacity and a moderate rate of evaporative water loss. Corn cobs absorb the least amount of water but retain the water longer than other bedding materials. Corn stover, wheat straw, and soybean stover have highest fertilizer value. Considering all characteristics, wheat straw, corn stover, and soybean stover are the most favorable materials to use in livestock housing systems. Abstract. Physical and chemical characteristics of organic bedding materials determine how well they will absorb and retain moisture and may influence the environment in livestock facilities where bedding is used. The objective of this study was to determine water holding capacity (WHC) and rate of evaporative water loss (EWL) of organic materials used as bedding in livestock facilities. Corn stover, soybean stover, wheat straw, switch grass, paper, corn cobs, and wood (pine and cedar) were evaluated; coarse, medium, and fine particle sizes of each bedding material were measured. The WHC was determined by submerging bedding materials in permeable nylon bags for 1, 3, 5, 10, 20, and 30 min, and 1, 3, 6, 9, 12, 24, 48, and 72 h. Generally, finely ground particles had higher WHC (P < 0.05) than the medium or coarsely ground particles of the same material. Corn stover (3.2 g g-1) and wheat straw (3.3 g g-1) had the highest WHC. Switch grass, dry cedar, green cedar, and corn cobs (1.4, 1.5, 1.6 and 1.9 g g-1, respectively) absorbed the least amount of water. Corn cobs retained water the longest when EWL was measured at 100°C, 25°C, and 15°C (6.0, 33.0, and 38.1 days, respectively). Based on N, P, and K content, corn stover, wheat straw, and soybean stover bedding had the highest fertilizer value of the bedding materials studied. Considering all characteristics, wheat straw, corn stover, and soybean stover are the most favorable bedding materials to use in livestock housing systems. Keywords: Bulk density, Corn stover, Evaporative water loss, Soybean stover, Switch grass, Water holding capacity, Wheat straw, Wood chips.

Determining the optimal modes of the technological process of obtaining dietary flour from oat grain

The article covers the results of study on determining the optimal modes of obtaining dietary flour from oat grains for the nutrition of little children and patients with dietetic disease. At first, the influence of the working space between the grooves of the milling machine on the yield of oat flour has been studied. The influence of the size of milled oat products on the quality of the finished product (flour that does not require cooking) was studied by changing the amount of starch and water-soluble substances in it, and optimum modes for the production of oat flour that does not require cooking, e.g. the amount of ground particles of 500…710 mcm in size is not more than 20.0%, the amount of particles of 150…355 mcm in size is 40.0%, the amount of particles smaller than 150 mcm is not less than 40.0%, etc. have been determined. The proposed technology allows obtaining ecologically clean products and protect the environment from pollution. The application of the obtained results in production allows increasing the type of dietary food products.

A DEM based scale-up model for tumbling ball mills

Scale-up of mills is critical to the design and operation of industrial grinding circuits. This paper presented a scale-up model based on the discrete element method (DEM) simulation to predict the performance of tumbling ball mills. The mills of different sizes partially filled with steel balls and ground particles were operated at different loading and speeds. The breakage energy characterized by the damping energy on the ground particles were analysed. In particular, a breakage model was adopted to link the breakage energy with particle mechanical properties to predict particle breakage in the mills. The predicted grinding rates of the particles under different conditions were comparable to experimental measurements. Results indicated that while particle-particle contacts were dominant in the flow, particle-ball contacts were the main breakage mechanism of particles. Power draw and grinding rate were not always positive correlated. Excessive mill speeds caused more power consumption but resulted in reduced grinding rate. Based on the simulation data, two scale-up models were proposed to predict power draw and grinding rate. The models were tested with larger mills and show excellent prediction on power draw and reasonable accuracy on grinding rate. • Tumbling mills filled with grinding balls and particles were simulated using DEM. • The damping energy on particles is more suitable than power draw to characterise mill efficiency. • Grinding rate of mills can be calculated by linking the damping energy and powder properties. • Scale-up models to predict power draw and grinding rate of mills were developed and validated.

Investigating the physical and chemical contribution of ground low-quality fly ash particles to cementitious composites

This work investigates grinding as a potential solution to improve the utilisation of low-quality fly ashes in concrete. Factors contributing to the performance of ground fly ash in cementitious composites were investigated. It was found that grinding significantly crushed large cenosphere particles and increased the specific gravity and surface area of fly ash, which led to a higher filler effect and improved the rate of cement hydration, contributing to strength development. The comparison of strength of quartz-blended pastes and fly ash-blended pastes showed that the pozzolanic reaction of fly ash marginally contributes to strength development. The major influence of ground particles was seen in the region near aggregates. Ground fly ash significantly increased the microhardness of the interfacial transition zone near aggregates. Since this zone has a direct influence on the failure of mortars and concrete, its improvement resulted in a comparable strength of fly ash-blended mortars to the reference ordinary Portland cement mortar.

Observation of Movement of Ground Particles Given Vibration When Rod Is Dragged

Supporting force, that a rod receives from the ground, is increased when vibration gives to the ground. This phenomenon is effective to improve the running performance for the legged rovers. In this study, the flow of the ground particles when a rod is dragged is measured using PIV for improving the running performance of the legged rovers. As observed from the experimental result, the larger the supporting force is, the larger the area that the particles move is. Therefore, the supporting force is related to the movement of the ground particles. Moreover, the area that the particles move becomes large by providing vibration whose frequency is high. The reason is considered that density is increased in a wide range of the ground when the vibration whose frequency is high. It is considered that the supporting force is increased by providing vibration to the ground because the area, that the particles move, grows by increasing density of the ground. The findings of this study suggest facilitating further planetary exploration using legged rovers.

A Computational Study on Rotor and Fuselage Configuration Effect on Rotorcraft Brownout

Rotorcraft brownout is an in-flight visibility restriction caused by clouds of sand and dust particles during landing, takeoff, and near-ground flight operations in arid desert terrain. This complex phenomenon is caused by the entrainment of dust, sand, and ground particles by rotor downwash and is compounded by fuselage geometry and its orientation with respect to the ground. Highly unsteady wind velocities are common in near-ground operations and play a significant role in the particulate cloud's behavior that creates the brownout condition. Experiments and flight tests to understand brownout are challenging, expensive, and risky. Alternatively, computational fluid dynamics (CFD) has been used extensively over the past few decades to study rotorcraft aerodynamics. However, there are additional computational challenges associated with modeling the dust particle transport in a brownout. In this work, a computationally efficient Eulerian-based framework has been developed to model rotorcraft brownout. The flowfield is modeled by Reynolds averaged Navier–Stokes (RANS) equation and is solved using the SIMPLER algorithm. Turbulence properties are modeled using Realizable κ – ε equations, while the rotor is modeled as a momentum source to focus on the global flowfield rather than the flow near the rotors. The Eulerian approach for both the flowfield and the dust transport allows computationally efficient and rapid analysis, taking an order of few hours in a single CPU to a fraction of an hour using GPU-based computation. In this work, results from two sets of experiments are presented. At first, a study on the fuselage's effect on brownout with respect to height for a single-rotor configuration in hover is demonstrated. Next, a study on the brownout characteristics of three rotor–fuselage configurations in hover, namely single-rotor, tandem-rotor, and quad-rotor, is presented. It has been observed that the ground friction velocity profile and flowfield vorticity around the rotorcraft play a significant role in dust cloud behavior. Additionally, the body forces and interference due to the fuselage plays a vital role in the formation of brownout dust clouds. The experiments showed that the quad-rotor is worst affected in terms of size and height of the dust clouds. However, the tandem-rotor has been found to be worst in the terms of average dust density.

Wear behavior of thermoplastic urethane for the outer soles of spike shoes

Thermoplastic urethane (TPU) is a major material for manufacturing studs for spike shoes. Spike shoes require high wear resistance and injection moldability. The TPU surface experiences impact and shear from soil ground particles. However, it is commonly difficult to estimate actual wear resistance of TPU studs based on table tests of solid particle erosion resistance or sliding wear resistance. In this study, we propose a new table test for estimating the wear resistance of TPU studs based on actual use in soccer activities. A wear resistance measurement method was developed where the TPU surface collided with abrasive paper and the wear volume measured in a table test. The wear volume increased with the storage elastic modulus of TPUs and was sensitive to the impact angle between TPU sheet and abrasive paper. These results were compared with the wear height of TPU studs from a practical use test, and it was confirmed that the wear resistance of TPU studs in a practical use matched to the results in table test when the abrasive paper on the TPU surface was struck at a 10° angle.

Are plastic particles reduced in size in seabirds' stomachs?

Many studies have quantified plastic loads in seabirds' stomachs but provide imprecise estimates of retention time. Quantifying retention time is fundamental for assessing biological impact and for the use of plastic as bioindicators of plastic pollution. Presumably, plastic is retained in the grinding section of the stomach (gizzard or ventriculus) until ground small enough and particles then pass into intestines and are defecated. We assume that particle size is related to time in the ventriculus and compared size of plastic particles in juveniles, which were exposed to plastic for a known time, to non-juveniles which were exposed for an unknown longer period. Plastic particles from Northern Fulmars (Fulmarus glacialis) were of similar size between groups suggesting similar wear and retention time. Cassin's Auklet (Ptychoramphus aleuticus) juveniles contained larger particles than adults suggesting particles retained in adults were worn down and thus held for a longer period.

Dynamic response and safety assessment of buried gas pipe subjected to ground surface explosion

Dynamic response of buried gas pipe subjected to the ground explosion is an important issue for the safety assessment of pipe. In this paper, the explosion tests of the full-scale model and 3D numerical models were employed to evaluate the dynamic response characteristics of the ground particles and the pipe. Meanwhile, parametric analysis was conducted to discuss the effects of different types of parameters for explosion source and pipe on the buried gas pipe's peak particle stress (PPS). Meanwhile, combined with the dynamic stress yield criterion of the pipe, the control standard of explosive charge under the action of the ground explosive load is obtained to prevent the damage of pipelines in different buried depths. The results showed that during third-party blasting operations, the internal pressure of the pipe should be reduced to better protect the pipe from damage, and attention should be paid to the velocity in the Y-direction of the pipe and the ground surface. Meanwhile, more attention should be paid to the safety protection of the buried pipe close to the interface between rock and soil.

Improved Approach in the Coupling Function Between Primary and Ground Level Cosmic Ray Particles Based on Neutron Monitor Data

Improved Approach in the Coupling Function Between Primary and Ground Level Cosmic Ray Particles Based on Neutron Monitor Data

Effects of Chemical Additives on Rheological Properties of Dry Ground Ore - a Comparative Study

ABSTRACT It is well documented that chemical additives (grinding aid “GA”) during grinding can increase mill throughput, reduce water and energy consumption, narrow the particle size distribution of products, and improve material flowability. These advantages have been linked to their effects on the rheology, although there is a gap in understanding GA effectiveness mechanism on the flow properties. The present study aims to fill this gap using different GAs (Zalta™ GR20-587, Zalta™ VM1122, and sodium hydroxide) through batch grinding experiments of magnetite ore and addressing the mechanisms of their effects on the rheology by an FT4 Powder Rheometer as a unique system. Experimental results showed that GA improved grinding efficiency (energy consumption and product fineness), which were well-correlated with basic flow energy, specific energy, aerated basic flow energy, and aerated energy. Moreover, the rheometry measurement showed strong linear correlations between basic flow energy, specific energy, and the resulting work index when GAs was considered for grinding, which confirmed the effect of GA on ground particles’ flowability. Zalta™ VM1122, a polysaccharide-based grinding aid, showed the best performance with 38.8% reduction of basic flow energy, 20.4% reduction of specific energy, 24.6% reduction of aerated basic flow energy, and 38.3% reduction of aerated energy. It also showed the strongest correlation between the grinding parameters and flow parameters (r > 0.93). The present investigation shows a strong indication that the predominant mechanism of GAs is based on the alteration of rheological properties and identify Zalta™ VM1122 as the best GA.

Cosmic Rays and Ultra High Energy Cosmic Rays (UHECR), GZK (Greisen-Zatsepin-Kuzmin) cutoff, Deflection angle of high energy cosmic rays in the propagation through the galactic and extragalactic magnetic fields, Auger Surface Detector and the Monitoring Data, Measurement of the Lifetime of Muons and Pions and The Variant Mass for a Particle in a Gravitational Field and the Binary Stars: The

The Surface Detector of the Pierre Auger Observatory consists of 1600 water Cherenkov tanks sampling ground particles of air showers produced by energetic cosmic rays. Every water tank is equipped with three photomultipliers (PMTs). Every 7 minutes monitoring data are recorded from each surface detector to ensure that they are performing as intended and also to understand the detector behavior. The monitoring data set is used to study the evolution of parameters of the PMTs as a function of both time and temperature. The main objective of the monitoring data is to monitor the stability of the PMTs. In case there is abnormal behavior detected, an alarm entry is created in the database. The classification of the alarms into different categories, corresponding to the observed patterns of the PMT variables and the decision of the alarm level are subject of this work. It is also researched the photomultipliers parameters and the alarm creation with examples of it: the Free Disk and High PMT gain change Alarms using c++, root and mysql. For other hand, it is researched about the measurement of the lifetime of muons and pions theoretically, experimentally and with the application of Statistics for the uncertainties of the results. The results have high accuracy and in accordance with the values of the literature. In addition, it is to analyze theoretically the deflection angle of the high energy cosmic rays in the propagation through the galactic and extragalactic magnetic fields. It is used the magnetic force formula and the Larmor radius, trigonometry, and the tables for the values of the galactic and extragalactic magnetic field and the distances to the galactic and extragalactic sources. It is possible to observe from this analysis that the deflection angles are very small for the considered cases. Thus, UHECR arrival directions should point back to their sources in the sky. Besides, it is researched about the GZK (Greisen-Zatsepin-Kuzmin) cutoff. A sharp cutoff at approximately several times 1019 eV in the energy spectrum of the cosmic rays is expected due to the energy degradation of the cosmic rays through their interaction with photons of the microwave background radiation. It is known as the GZK (Greisen-Zatsepin-Kuzmin) cutoff. A nucleon with an initial energy above Eo=1020 eV lose about 1/5 of Eo (initial energy) in each interaction. Thus, a nucleon of initial energy above 1020 eV will reduce its energy to 6*1019 eV (GZK cutoff energy) after traveling a distance of approximately 50 Mpc. For other hand, Albert Einstein wrote in a research article: “Does the inertia of a body depend on its energy content?” (Ist die Tragheit eines Korpers von seimen Energienhalt abhangig?): “If a body emits energy E in the form of radiation, its mass decreases by E/c2”. Thus, Maxwell's theory shows that electromagnetic waves are radiated whenever charges accelerate as for example for the electron. Then, this electromagnetic radiation (photons) produces a decrease in the mass of the electron which is given by the formula of the Variant Mass for an Accelerated Charged Particle which was demonstrated by me at this research [34] and at the research of the Variant Mass of the Electron at the Atom. This is true for any type of radiation emitted: electromagnetic or gravitational energy which produce a decrease in the mass of the body. Therefore, other objective of this article is to demonstrate the discovered formula which describes exactly the variant mass for a particle which emits gravitational energy. An example of the effect of this Gravitational energy emission is the light deflection for the light passing close the Sun (gravitational redshift frequency) and the Perihelion Precession of Mercury. Thus, the results of the mass formula are of great relevance for Gravitational Interactions. The results are in accordance with the classic result for the emission of the total gravitational energy (bond total energy) for a particle orbiting a large Planet or Sun and for a Binary Star. It is in agreement with the experiment result and with the Theory of General Relativity.