Antiwear Properties of Commercial Grease as a Function of Particle Morphology and Uniformity of the As-Synthesized Calcium Carbonate Additive

2020 ◽  
Vol 143 (4) ◽  
Author(s):  
Khalida Akhtar ◽  
Saniya Yousafzai
Keyword(s):  
Particle Size ◽  
Calcium Carbonate ◽  
Tribological Properties ◽  
Particle Morphology ◽  
Optimum Amount ◽  
Lithium Grease ◽  
Antifriction Additive ◽  
Key Factor ◽  
Antiwear Properties ◽  
Particle Size And Shape

Abstract Calcium carbonate powder comprising uniform nanoparticles of novel morphology was synthesized under extensively optimized trial parameters. The as-prepared ultrafine rod shape CaCO3 particles after characterizations were used as an antiwear/antifriction additive in commercial lithium grease (CLG) of different specifications. The effect of the added particles on the antifriction and antiwear properties of the blended commercial greases was explored by using a ball-on-disk tribometer. The observed data were compared with the additized grease having commercially available CaCO3 powder. Results exposed that uniformity in particle size and shape is a key factor for the improvement of tribological properties and reproducibility of the experimental results. Therefore, the as-prepared monodispersed rod shapes CaCO3 particles as additives considerably improved the tribological properties of the CLG as compared with the irregular particles of the commercial calcium carbonate. These blends showed the best results at the optimum amount of 3 wt% of the added CaCO3 particles. Among the three selected greases, the additized Momin grease exhibited best antiwear/antifriction performance as compared with the additized Awami and Sinopec greases.

scholarly journals Particle Morphology Analysis of Biomass Material Based on Improved Image Processing Method

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Zhaolin Lu ◽  
Xiaojuan Hu ◽  
Yao Lu
Keyword(s):  
Image Processing ◽  
Particle Size ◽  
Particle Morphology ◽  
Processing Method ◽  
Image Resolution ◽  
Ultrasonic Dispersion ◽  
Image Processing Method ◽  
Size And Shape ◽  
Nominal Size ◽  
Particle Size And Shape

Particle morphology, including size and shape, is an important factor that significantly influences the physical and chemical properties of biomass material. Based on image processing technology, a method was developed to process sample images, measure particle dimensions, and analyse the particle size and shape distributions of knife-milled wheat straw, which had been preclassified into five nominal size groups using mechanical sieving approach. Considering the great variation of particle size from micrometer to millimeter, the powders greater than 250 μm were photographed by a flatbed scanner without zoom function, and the others were photographed using a scanning electron microscopy (SEM) with high-image resolution. Actual imaging tests confirmed the excellent effect of backscattered electron (BSE) imaging mode of SEM. Particle aggregation is an important factor that affects the recognition accuracy of the image processing method. In sample preparation, the singulated arrangement and ultrasonic dispersion methods were used to separate powders into particles that were larger and smaller than the nominal size of 250 μm. In addition, an image segmentation algorithm based on particle geometrical information was proposed to recognise the finer clustered powders. Experimental results demonstrated that the improved image processing method was suitable to analyse the particle size and shape distributions of ground biomass materials and solve the size inconsistencies in sieving analysis.

Dextran-induced modifications of calcium carbonate particles precipitated during carbonatation

2019 ◽  
pp. 382-391
Author(s):  
Karin Abraham ◽  
Liza Splett ◽  
Eckhard Flöter
Keyword(s):  
Particle Size ◽  
Image Analysis ◽  
Calcium Carbonate ◽  
Filter Cake ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Shape Parameters ◽  
Size And Shape ◽  
Static Image ◽  
Particle Size And Shape

The effects of high and low molecular mass dextran (T2000 and T40) on the size and shape of particles precipitated during carbonatation and their correlation with filtration performances were key to this study. Varying contents of T2000 and T40 dextran in sugar solutions corresponding to DS contents of thin juice were investigated. For particle size and shape analysis, static image analysis and laser particle size analysis were used. Both methods, static image analysis and laser diffraction, revealed that the presence of T2000 and T40 dextran leads to a higher amount of large-sized particles at the expense of small-sized particles, indicating pronounced agglomeration. The additional evaluation of shape parameters (circularity, roundness, solidity) obtained from static image analysis indicates that the agglomeration is oriented in the absence and in the presence of lower T40 dextran levels. Besides, non-oriented agglomeration, resulting in more round agglomerates with smoother surfaces, was found for samples loaded with T2000 dextran and high T40 dextran levels. Only the latter samples have shown to negatively affect the filtration performance. Thus, in the presence of T2000 dextran and high T40 dextran levels, the filtration was hampered. This appears to be mainly caused by a tighter packing of more round calcium carbonate agglomerates in the porous structure of the filter cake.

scholarly journals Synthetic calcium carbonate improves the effectiveness of treatments with nanolime to contrast decay in highly porous limestone

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Radek Ševčík ◽  
Alberto Viani ◽  
Dita Machová ◽  
Gabriele Lanzafame ◽  
Lucia Mancini ◽  
...  
Keyword(s):  
Particle Size ◽  
Calcium Carbonate ◽  
Stone Decay ◽  
Micro Computed Tomography ◽  
Non Invasive ◽  
Matrix Microstructure ◽  
Particle Size And Shape ◽  
Positive Effect ◽  
Highly Porous ◽  
Negligible Contribution

Abstract Three synthetized polymorphs of calcium carbonate have been tested in combination with the suspension of nanolime particles as potential consolidating agents for contrasting stone decay and overcome some of the limitations of nanolime agents when applied to substrates with large porosity. The modifications induced in the pore network of the Maastricht limestone were analyzed with microscopy and in a non-invasive fashion with small angle neutron scattering and synchrotron radiation micro-computed tomography. A reduction in porosity and pore accessibility at the micrometric scale was detected with the latter technique, and ascribed to the improved pore-filling capacity of the consolidation agent containing CaCO3 particles. These were found to be effectively bound to the carbonated nanolime, strengthening the pore-matrix microstructure. Penetration depth and positive effect on porosity were found to depend on the particle size and shape. Absence of significant changes in the fractal nature of the pore surface at the nanoscale, was interpreted as indication of the negligible contribution of nanolime-based materials in the consolidation of stones with large porosity. However, the results indicate that in such cases, their effectiveness may be enhanced when used in combination with CaCO3 particles, owing to the synergic effect of chemical/structural compatibility and particle size distribution.

Physics based models for metal hydride particle morphology, distribution, and effective thermal conductivity

2009 ◽  
Vol 1172 ◽  
Author(s):  
Kyle Christopher Smith ◽  
Timothy Fisher
Keyword(s):  
Thermal Conductivity ◽  
Particle Size ◽  
Effective Thermal Conductivity ◽  
Metal Hydride ◽  
Metal Hydrides ◽  
Particle Morphology ◽  
Particle Packing ◽  
Interparticle Contact ◽  
Storage Media ◽  
Particle Size And Shape

AbstractThis paper describes a modeling approach to target aspects of heat conduction in metal hydride powders that are essential to metal hydrides as viable H2storage media, including particle morphology distribution, size distribution, particle packing properties at specified solid fraction, and effective thermal conductivity. An isotropic fracture model is presented that replicates features of particle size and shape distributions observed experimentally. The discrete element method is used to simulate evolution of metal hydride particle contact networks during quasi-static consolidation of decrepitated metal hydride powders. Finally, the effective thermal conductivity of such a powder is modeled assuming that contact conductance is the same for each interparticle contact.

scholarly journals Overview of Algorithms for Using Particle Morphology in Pre-Detonation Nuclear Forensics

Algorithms ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 340
Author(s):  
Tom Burr ◽  
Ian Schwerdt ◽  
Kari Sentz ◽  
Luther McDonald ◽  
Marianne Wilkerson
Keyword(s):  
Particle Size ◽  
Nuclear Forensics ◽  
Review Paper ◽  
Particle Morphology ◽  
Adsorbed Water ◽  
Processing Conditions ◽  
Uranyl Carbonate ◽  
Attractive Option ◽  
Particle Size And Shape ◽  
Approximate Bayesian

A major goal in pre-detonation nuclear forensics is to infer the processing conditions and/or facility type that produced radiological material. This review paper focuses on analyses of particle size, shape, texture (“morphology”) signatures that could provide information on the provenance of interdicted materials. For example, uranium ore concentrates (UOC or yellowcake) include ammonium diuranate (ADU), ammonium uranyl carbonate (AUC), sodium diuranate (SDU), magnesium diuranate (MDU), and others, each prepared using different salts to precipitate U from solution. Once precipitated, UOCs are often dried and calcined to remove adsorbed water. The products can be allowed to react further, forming uranium oxides UO3, U3O8, or UO2 powders, whose surface morphology can be indicative of precipitation and/or calcination conditions used in their production. This review paper describes statistical issues and approaches in using quantitative analyses of measurements such as particle size and shape to infer production conditions. Statistical topics include multivariate T tests (Hotelling’s ), design of experiments, and several machine learning (ML) options including decision trees, learning vector quantization neural networks, mixture discriminant analysis, and approximate Bayesian computation (ABC). ABC is emphasized as an attractive option to include the effects of model uncertainty in the selected and fitted forward model used for inferring processing conditions.

scholarly journals Controlling Calcium Carbonate Particle Morphology, Size, and Molecular Order Using Silicate

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3525
Author(s):  
Lior Minkowicz ◽  
Arie Dagan ◽  
Vladimir Uvarov ◽  
Ofra Benny
Keyword(s):  
Calcium Carbonate ◽  
Calcium Nitrate ◽  
Particle Morphology ◽  
Industrial Applications ◽  
Spherical Particles ◽  
Precipitation Reaction ◽  
Single Particles ◽  
X Ray ◽  
Key Factor ◽  
Calcium Carbonate Particle

Calcium carbonate (CaCO3) is one of the most abundant substances on earth and has a large array of industrial applications. Considerable research has been conducted in an effort to synthesize calcium carbonate microparticles with controllable and specific morphologies and sizes. CaCO3 produced by a precipitation reaction of calcium nitrate and sodium carbonate solution was found to have high polymorphism and batch to batch variability. In this study, we investigated the polymorphism of the precipitated material and analyzed the chemical composition, particle morphology, and crystalline state revealing that the presence of silicon atoms in the precipitant is a key factor effecting particle shape and crystal state. An elemental analysis of single particles within a polymorphic sample, using energy-dispersive X-ray spectroscopy (EDS) conjugated microscopy, showed that only spherical particles, but not irregular shaped one, contained traces of silicon atoms. In agreement, silicon-containing additives lead to homogenous, amorphous nanosphere particles, verified by X-ray powder diffraction (XRD). Our findings provide important insights into the mechanism of calcium carbonate synthesis, as well as introducing a method to control the precipitants at the micro-scale for many diverse applications.

Effect of CO2 Flow Rate on the Synthesis Nanosized Precipitated Calcium Carbonate, PCC

2013 ◽  
Vol 481 ◽  
pp. 72-75
Author(s):  
O. Nooririnah ◽  
Azwar Azhari Muhamad ◽  
Y. Yusliza ◽  
Abreeza Manap ◽  
M.J. Md Ashadi
Keyword(s):  
Particle Size ◽  
Wastewater Treatment ◽  
Calcium Carbonate ◽  
Ionic Strength ◽  
Calcium Hydroxide ◽  
Flow Rate ◽  
High Purity ◽  
Precipitated Calcium Carbonate ◽  
Particle Size And Shape ◽  
Spraying Method

The precipitated of calcium carbonate has attractedmuch attention because of its numerous applications in various areas of plastics, textiles, rubbers, adhesives, paints and wastewater treatment. Nanosized of precipitated calcium carbonate,(PCC) will enhance the properties and give better performance. Its high purity and close controlled particle size and shape are making it the white filler of choice. Nanosized precipitated calcium carbonate particles were prepared using spraying method. The particles were prepared using three (3) different concentrations of Calcium Hydroxide,Ca (OH)2, three (3) CO2flow rate and three (3) different calcinations temperature. The three (3) concentration of Calcium Hydroxide that been used are 25g/200ml, 25g/ 400ml and 25g/800ml and each of these initial solution sprayed at three (3) different CO2flow rate, 5l/per-minute, 7l/per-minute and 10l/per-minute. Calcium Carbonate, CaCO3powders were then calcined at three (3) different temperature, 1100°C,1200°C and 1300°C. Images from SEM showed morphology of the particles changed to spindle-like or prismatic when the ionic strength of the Calcium Hydroxide, Ca (OH)2was increased.

Surface energy of cellulosic materials: The effect of particle morphology, particle size, and hydroxyl number

TAPPI Journal ◽  
2015 ◽  
Vol 14 (9) ◽  
pp. 565-576 ◽  
Author(s):  
YUCHENG PENG ◽  
DOUGLAS J. GARDNER
Keyword(s):  
Particle Size ◽  
Surface Energy ◽  
Particle Morphology ◽  
Nanofibrillated Cellulose ◽  
Particle Sizes ◽  
Hydroxyl Number ◽  
Small Individual ◽  
Dispersion Component ◽  
Commercial Applications ◽  
Lower Temperature

Understanding the surface properties of cellulose materials is important for proper commercial applications. The effect of particle size, particle morphology, and hydroxyl number on the surface energy of three microcrystalline cellulose (MCC) preparations and one nanofibrillated cellulose (NFC) preparation were investigated using inverse gas chromatography at column temperatures ranging from 30ºC to 60ºC. The mean particle sizes for the three MCC samples and the NFC sample were 120.1, 62.3, 13.9, and 9.3 μm. The corresponding dispersion components of surface energy at 30°C were 55.7 ± 0.1, 59.7 ± 1.3, 71.7 ± 1.0, and 57.4 ± 0.3 mJ/m2. MCC samples are agglomerates of small individual cellulose particles. The different particle sizes and morphologies of the three MCC samples resulted in various hydroxyl numbers, which in turn affected their dispersion component of surface energy. Cellulose samples exhibiting a higher hydroxyl number have a higher dispersion component of surface energy. The dispersion component of surface energy of all the cellulose samples decreased linearly with increasing temperature. MCC samples with larger agglomerates had a lower temperature coefficient of dispersion component of surface energy.

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