Browsing by Subject "Particle size distribution"
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Item Comparative analysis of lost circulation material particle size and degradation in drilling fluids(2015-05) Yang, Lin, M.S.E.; Oort, Eric van; Hale, Arthur H.Lost Circulation Materials (LCM) are used to plug natural and induced fractures to minimize drilling fluid loss to formations. Various LCMs are available in field application, such as calcium carbonate and graphite. Design of the particle size distribution is crucial to successfully mitigate loss circulation. It is common industry practice to rely on the particle size distribution as specified by the product data sheet when designing lost circulation pills. During mud circulation, there are several instances where LCMs are exposed to high shear rates, such as during fluid mixing at the hopper, going through mud pumps, and exiting through the bit nozzles. Using sensitive focused beam reflectance measurement (FBRM) techniques, reliable laser diffraction and sophisticated image analysis, we have found that size degradation of calcium carbonate and graphite under such shearing conditions occurs at a lower shearing rate - and to a much larger extent - than previously assumed. This, then, calls into question the effectiveness of calcium carbonate and graphite for LCM applications that rely on size maintenance for effective bridging purposes.. Based on the experimental results, the field personnel can take size degradation effects into account and compensates accordingly. Unexpectedly, particle measurements from sieve analysis, FBRM, laser diffraction and image analysis are quantitatively different. This can be attributed to the various definitions of particle diameters and the limitation of each techniques. Image analysis provides the most accurate particle sizing information but the reproducibility of the corresponding equipment is questionable. Laser diffraction is fast and reliable but will be affected by the sampling method and the degree of dispersion. FBRM requires no dilution to the sample, but provides chord length measurement which is very different from the equivalent spherical diameter (the prevailing diameter definition). In this study, we will show the size degradation results of calcium carbonate and graphite, and the detailed evaluation of the three commercial particle size analyzers used in the experiments.Item Effect of Powder Characteristics on Fatigue Performance of Additively Manufactured 17-4 PH Stainless Steel(2022) Poudel, Arun; Soltani-Tehrani, Arash; Shao, Shuai; Shamsaei, NimaThe characteristics of powder feedstock used during laser powder bed fusion (L-PBF) influence the mechanical performance of the fabricated parts. The flowability, spreadability, and internal porosity of the powder can affect the porosity formation and thus, impact the fatigue performances. Two batches of 17-4 precipitation hardening stainless steel powders supplied by two different vendors were used to fabricate the L-PBF specimens and investigate the effect of powder characteristics on porosity and fatigue behavior. The powder batch with a wider particle size distribution, higher compressibility, higher cohesion between powder particles, and internal porosity resulted in a higher defect content in the fabricated specimens. Higher defect content led to inferior fatigue resistance along with more scatter in the fatigue lives. Fractography revealed the fatigue crack initiation from spherical pores as well as the lack of fusions in both batches.Item Fluoride, natural organic matter, and particles : the effect of ligand competition on the size distribution of aluminum precipitates in flocculation(2016-05) Herrboldt, Jonathan Philip; Lawler, Desmond F.; Katz, Lynn EllenFluoride occurs at elevated concentrations naturally in surface and ground waters around the world. If consumed at low concentrations in drinking water (< 1.5 mg/L), fluoride is shown to reduce the occurrence of dental caries and the Centers for Disease Control and Prevention named fluoridation of public water systems one of the 10 Great Public Health Achievements of the 20th Century (CDC, 1999). However, prolonged exposure to high concentrations of fluoride (> 2.0 mg/L) causes adverse health effects to teeth and bones. For this reason the United State Environmental Protection Agency (USEPA) enacted a maximum contaminant level (MCL) for fluoride at 4.0 mg/L. This rule is currently under review following a recent risk assessment and may be lowered. If the MCL were lowered, water systems previously meeting treatment standards would suddenly find themselves out of compliance and will need to implement additional treatment to meet the new standard. Defluoridation by alum coagulation is a proposed defluoridation method. However, the interaction between fluoride and natural organic matter (NOM) and their effects on the particle size distribution of aluminum precipitates is not well understood. Because the particle size distribution of aluminum precipitates is an important parameter in the efficiency of sedimentation and filtration systems, a thorough understanding of these interactions and their potential effect on sedimentation and filtration is needed to inform the implementation of defluoridation by alum coagulation. This work utilized a series of jar tests on synthetic surface water to determine the effect of fluoride and NOM on the particle size distribution of aluminum precipitates. It was found that fluoride caused the volume distribution of aluminum precipitates to shift toward smaller particle sizes. However, NOM caused the formation of a larger number of aluminum precipitates, which resulted in a dramatic increase in the total volume of precipitates. When both fluoride and NOM were in the system, a combination of the two effects was observed: the volume distribution shifted toward smaller particle sizes but the peak of the distribution shifted toward a greater volume, indicating both smaller particles were being formed and a greater overall volume of particles precipitated.Item Impact of angularity, particle size and particle size distribution on the stiffness of the soil-geosynthetic composite(2023-03-24) Brikalski, Miqueias P.; Zornberg, Jorge G.Comparatively small strains are mobilized when the geosynthetic is used for its stiffening function, as is the case in the stabilization of road bases. The objective is to control the deformation in the soil-geosynthetic composite. Fundamental to accomplishing that is the increased stiffness resulting from the soil-geosynthetic interaction. The soil-geosynthetic composite (SGC) model combines the tensile properties of the geosynthetic with the shear strength properties of the soil-geosynthetic interface, under low strain conditions, into a single parameter, the stiffness of the soil-geosynthetic composite (K [subscript SGC]). This study evaluated the impact of aggregate angularity, particle size, and particle size distribution on the K [subscript SGC] involving geogrids and geotextiles using the small-scale soil-geosynthetic interaction (SGI) test. The results indicate that aggregate angularity and particle size distribution impact the K [subscript SGC], increasing its value for both geosynthetic types. The increase was more significant in the case of geotextiles than in the case of geogrids. The magnitude of the increase was found to also be affect by the tensile modulus of the geosynthetic (J). The impact of particle size on K [subscript SGC] was observed to be very small for both geosynthetic types. When evaluating the suitability of aggregates involved in this study to be used as a reference when testing geotextiles, it was found that aggregate angularity facilitates the assessment of geotextile performance.