scholarly journals Mineralogy (XRD)

2021 ◽  
pp. 95-119
Author(s):  
Ali Al-Dousari ◽  
Muntha Bahbahani

Abstract The two main particle size components of the dust samples were subjected to mineralogical analysis to identify the mineral constituents and determine their frequency percentage in each textural class; the fine sand (particle size between 0.125 and 0.063 mm) and Mud (less than 0.063 mm). The average percentage of minerals was mapped out for each season i.e. March, June, September and December 2010 showing the high and low mineral concentration in areas in Kuwait covering the mineral concentrations of Calcite, Carbonate, clay minerals, dolomite, feldspars, and quartz.

2020 ◽  
Vol 15 (2) ◽  
pp. 8-12
Author(s):  
A.S. Aremu ◽  
T.K. Amao ◽  
O.A. Mokuolu

This study investigated the effect of different particle sizes of sand bed anti-vibration mount on transmitted noise from a portable on-site electricity generator. Ten sand bed anti-vibration mounts, 650mm x 650mm in cross section and 75mm thickness were prepared with particle sizes ranging from 0.09 to 2.30mm. Noise measurements were taken in the four cardinal directions using Extech HD600 digital sound level meter. The results of the study showed that the ability of the sand particles to dampen vibration noise from the portable electricity generator reduces with increase in particle size. The sand bed anti-vibration mounts reduced noise levels by 0.11 to 2.78 dB(A). However, fine sand bed of particle size 0.09mm and 0.15mm exhibited superiority in noise reduction over all other sand beds. In order to achieve appreciable noise reduction, the use of ISO 14688-1:2002 fine sand category is recommended as anti-vibration mount in combination with other damping methods. Keywords: Electricity generator, noise, sand, particle size and attenuation


2018 ◽  
Vol 2 (6) ◽  
Author(s):  
Tânia Santos ◽  
M. Idália Gomes ◽  
Flávia Coelho ◽  
Paulina Faria

Earth construction, including the use of earth mortars, has been extensively used in the past. However, with the appearance of hydraulic binders, the use of earth strongly decreased for new construction and even to repair old earth buildings, whose best solution would be the use of compatible materials such as earth mortars.Due to the innumerable advantages of earth and with the growing concern on eco-efficient construction, the interest on earth construction has resurfaced, namely on earth mortars.In order to optimize the composition of an earth plastering mortar made with a defined clayish earth and two siliceous sands with different particle size, six compositions were assessed. Mortars with different volumetric ratios were applied in two different supports (on the back of a tile and on a brick) and planar specimens were also produced. Distinct characteristics were assessed, such as their visual appearance, shrinkage, surface cohesion, surface hardness, dry abrasion resistance, ultrasonic velocity, adhesive strength and thermal conductivity.It is possible to conclude that a higher clay content in the earth mortar composition increases the shrinkage and occurrence of cracking, the use of fine sand promotes high mass loss by abrasion, and the same mortar applied in different supports behave differently in terms of durability.


1984 ◽  
Vol 19 (1) ◽  
pp. 27-36 ◽  
Author(s):  
Alena Mudroch

Abstract Surface sediment samples obtained at the offshore and nearshore area of Lake Erie were separated into eight different size fractions ranging from <2 µm to 250 µm. The concentration of major elements (Si, Al, Ca, Mg, K, Na, Fe, Mn and P), metals (Zn, Cu, Cr, Ni, V, Co and Pb) and organic matter was determined together with the mineralogical composition and morphology of the particles in each size fraction. The distribution of the metals in the offshore sediment was bimodal with the majority of the metals divided between the 63 to 250 um size fraction which also contained the highest concentration of organic matter (about 20%) and the <4 µm fraction containing up to 60% of clay minerals. However, the metals in the nearshore sediment were associated mainly with the clay minerals.


Clay Minerals ◽  
1969 ◽  
Vol 8 (1) ◽  
pp. 59-69 ◽  
Author(s):  
G. Halma

Because of increased interest in mineralogical analysis of soils a rapid, generally applicable method to separate clay minerals is needed, and such a method is described here. The technique is a modification of the heavy liquid density gradient centrifugation method which is commonly applied in mineralogical practice. Modifications are:(1)The use of suitable surface active agents to overcome the flocculation problem.(2)The use of the ultra centrifuge at about 33,000 g to hasten sedimentation.(3)The use of a linear density gradient which supplies in addition a quick identification of the mineral composition.Preliminary experiments, evaluating different variables (e.g. cation form, ultrasonic treatment, influence of surfactant), reveal the scope and limitations of the procedure presented.Clay minerals of different density can be separated. However, if the clay minerals of a mixture have overlapping densities, or if they contain a series of mixed-layer minerals, only a broad fractionation is possible. This is shown by X-ray diffraction and electron microscope studies of isolated zones (or parts of them) which develop in the centrifuged density gradient columns containing various pre-treated natural clays or clay mixtures.


2019 ◽  
Vol 37 (4) ◽  
pp. 437
Author(s):  
Adriana Mellado-Vázquez ◽  
Samuel Salazar-García ◽  
Ricardo Goenaga ◽  
Alfredo López-Jiménez

In Mexico there are more than 201 400 ha grown with different mango (Mangifera indica L.) cultivars. This may cause variations in mineral requirement, fruit mineral concentrations and nutrient removal. The objective of this research was to make a survey of mineral concentration in fruit tissues and calculate nutrient removal by fruit tissues during harvest of the most important mango cultivars (Ataulfo, Kent and Tommy Atkins) from several production regions (Campeche, Chiapas, Oaxaca, Nayarit, and Sinaloa) of Mexico. Fruit at physiological maturity were harvested from commercial mango orchards and concentration of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), iron (Fe), copper (Cu), manganese (Mn), zinc (Zn) and boron (B) was determined for skin, mesocarp, endocarp, and seed tissues. Each tissue was cut into thin slices and they were dehydrated in a forced air oven at 70 °C, after that, were pulverized and they were analyzed: nitrogen by semi-microKjeldahl digestion, phosphorus with the ascorbic acid method and the other nutrients with atomic absorption. The removal of nutrients was calculated considering the weight of the fruit and the content of nutrients in each tissue. Signif icant differences in the concentration of N, K, Mg, and Zn were found among cultivars and tissues. Concentration of P, S, Cu, and Mn in the skin, Ca, Cu, and Mn in the mesocarp, Ca, S, Mn, and B in endocarp, and S, Fe, and Mn in the seed were not affected by mango cultivar. Production region affected concentration of minerals in ‘Ataulfo’ fruit more than in ‘Tommy Atkins’ and ‘Kent’. Nutrient removal by mango fruit tissues was little affected in cvs. Ataulfo, Tommy Atkins and Kent. The regions with the greatest nutrient removal were Oaxaca, Campeche and Sinaloa for ‘Ataulfo’, ‘Tommy Atkins’ and ‘Kent’, respectively.


2019 ◽  
Vol 59 (4) ◽  
pp. 617-640
Author(s):  
O. N. Kolesnik ◽  
A. N. Kolesnik ◽  
E. G. Vologina ◽  
A. A. Maryash

The data on mineralogical analysis of fine sand fractions in sediments accumulated in the southern part of the Chukchi Plateau during the Quaternary are presented. The associations and downcore distribution of the rock-forming and accessory minerals in relation to other characteristics are considered. The established climatically controlled mineralogical features, i. e. periodicity of warmings and coolings, can be used in solving a number of genetic problems, stratigraphic subdivision of sediments and paleoreconstructions.


Author(s):  
Risa Okita ◽  
Yongli Zhang ◽  
Brenton S. McLaury ◽  
Siamack A. Shirazi ◽  
Edmund F. Rybicki

Zhang et al (2006) utilized CFD to examine the validity of erosion models that have been implemented into CFD codes to predict solid particle erosion in air and water for Inconel 625. This work is an extension of Zhang’s work and is presented as a step toward obtaining a better understanding of the effects of fluid viscosity and sand particle size on measured and calculated erosion rates. The erosion rates of Aluminum 6061-T6 were measured for direct impingement conditions of a submerged jet. Fluid viscosities of 1, 10, 25, and 50 cP and sand particle sizes of 20, 150, and 300 μm were tested. The average fluid speed of the jet was maintained at 10 m/s. Erosion data show that erosion rates for the 20 and 150 μm particles are reduced as the viscosity is increased, while surprisingly the erosion rates for the 300 μm particles do not seem to change much for the higher viscosities. For all viscosities considered, larger particles produced higher erosion rates, for the same mass of sand, than smaller particles. Concurrently, an erosion equation has been generated based on erosion testing of the same material in air. The new erosion model has been compared to available models and has been implemented into a commercially available CFD code to predict erosion rates for a variety of flow conditions, flow geometries, and particle sizes. Since particle speed and impact angle greatly influence erosion rates of the material, calculated particle speeds were compared with measurements. Comparisons reveal that, as the particles penetrate the near wall shear layer, particles in the higher viscosity liquids tend to slow down more rapidly than particles in the lower viscosity liquids. In addition, CFD predictions and particle speed measurements are used to explain why the erosion data for larger particles is less sensitive to the increased viscosities.


1988 ◽  
Vol 68 (3) ◽  
pp. 671-681 ◽  
Author(s):  
N. M. MILES ◽  
C. R. De KIMPE

Samples were collected from Ap/Ah and Bm horizons of 10 soils from southeastern Ontario. The soil reaction ranged from medium acid to mildly alkaline. Mineralogical analysis of the various particle-size fractions showed the presence of corrensite, talc and graphite in the assemblage. These three minerals were also present in large amounts in marble outcrops, where they were formed by hydrothermal alteration and metamorphism. The significance of inherited interstratified minerals in the soils was considered from the analytical aspect: the first-order basal reflection should be confirmed because higher orders could be confounded with other mineral reflections; and from the pedogenetic aspect: failing to recognize an inherited interstratified mineral would be misleading in the interpretation of soil evolution. Key words: Grenville province, interstratified mineral, corrensite, talc, graphite, inherited minerals


2018 ◽  
Vol 66 (6) ◽  
pp. 356 ◽  
Author(s):  
Taylor A. Stewart ◽  
David T. Booth ◽  
Mohd Uzair Rusli

The nest microenvironment affects hatching and emergence success, sex ratios, morphology, and locomotion performance of hatchling sea turtles. Sand grain size is hypothesised to influence the nest microenvironment, but the influence of sand grain size on incubation of sea turtle eggs has rarely been experimentally tested. At the Chagar Hutang Turtle Sanctuary, Redang Island, Malaysia, green turtle (Chelonia mydas) nests were relocated to sands with different sand grain sizes on a natural beach to assess whether grain size affects nest temperature, oxygen partial pressure inside the nest, incubation success, hatchling morphology and hatchling locomotion performance. Green turtle nests in coarse sand were cooler; however, hatching success, nest emergence success, oxygen partial pressure, incubation length and hatchling size were not influenced by sand particle size. Nests in medium-grained sands were warmest, and hatchlings from these nests were better self-righters but poorer crawlers and swimmers. Hatchling self-righting ability was not correlated with crawling speed or swimming speed, but crawling speed was correlated with swimming speed, with hatchlings typically swimming 1.5–2 times faster than they crawled. Hence, we found that sand particle size had minimal influence on the nest microenvironment and hatchling outcomes.


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