A comprehensive study of synthesis and applications of core/shell nanoparticles

When we consider matter at nanoscale, one of the most important aspects to be considered is that due to the small size of the particles, these have increased surface area to volume ratio. The large value of this ratio increases the dominance of the surface atoms of the nanoparticles in relation to those in its interior. A special category of materials at nanoscale level has gained popularity in the recent times due to their interesting properties and applications. When classified on the basis of structure, the types of core/shell particles can have a large variety. Each of this structural classification has its own importance, method of synthesis and application. The core/shell nanoparticles have some distinct features that is responsible for their importance. The properties of Core/shell nanoparticles are highly modified from that of their simple pure nanomaterials, thus they usually called highly functional materials. The introduction of a different crust layer over the core particle has many reasons, such as it helps in implementing surface modification, increases functionality, stability and dispersibility, control on the release of the core, lowering the consumption of precious materials, and so on. These nanostructures can have a number of combinations in close interaction, depending upon the selection of material used, which highly influences the end application. This paper has an overview of the present methods involved in synthesis and tunable factors responsible for their end applications. The development of metal/metal oxide core-shell nanoparticles has become popular nowadays due to their widespread use in catalysis and other environmental remedial applications.

Sediment Thickness and Moho Depth Beneath Western Indonesian Region From Teleseismic Receiver Function

The Earth's crust layer and sediment in Western Indonesia has been studied using the inversion of teleseismic receiver function from BMKG’s seismic network. Earthquake events were analyzed in this study with a moment magnitude greater than 6.0 with epicentral distances of 30° to 90°. A total of 60 earthquake events were observed and recorded by 91 stations around the study area. Furthermore, an inversion process was carried out using the initial velocity model from the modification of the AK135f velocity model to obtain the shear wave velocity structure below each stations. The velocity model from the azimuthally stacked vertical receiver function showed that the sediment layer had a relatively medium shear wave velocity value with an average of 2.1 km/s, while the crust layer had 4.60 km/s. The sedimentary layer thickness in this region also varies between 2 km to 10 km. A relatively thick sediment layer of about 8 km to 10 km was observed in two locations, in East Kalimantan associated with the Kutai Basin and Northern part of Sumatera in the North Sumatera Basin, a two major oil producer basinal area in Indonesia. The Moho discontinuity was also found at depths that vary between 16 km to 50 km. In addition, the most shallow Moho depth is 16 km below the North Kalimantan and North part of West Java, while the deeper Moho depth of 50 km is located below East Kalimantan, Central Kalimantan, North Sumatera and South Sumatera.

Use of Filter Cake Powder for Enhancing Soil Stability of Active Sand Dunes

Filter cake powder (FCP) is a residual material and the main solid waste of sugar production from sugarcane. This material contains high concentrations of polysaccharides and fats. FCP has previously been shown to act as a soil improver. Active sand dunes (ASD) in arid and semiarid regions, cover agriculture fields, and cause significant damage to field crops and livelihood. Therefore, it is necessary to find a treatment which would improve ADS soil stability. Biological soil crusts (biocrusts) are communities of living organisms on the soil surface in arid and semi-arid ecosystems. It was clearly shown that metabolic polysaccharides secreted by biocrust cyanobacteria, glue the soil particles to aggregates which form the crust layer, thereby stabilizing the soil surface. The aim of this study was to investigate the effect of FCP on ASD stability. We hypothesized that the addition of FCP to the ASD surface would enhance soil polysaccharide content, and that this would lead to soil stabilization improvement. The degree of soil stability was determined using penetration resistance soil biocrust (PRSB) measurements. It was found that FCP treatment increased PRSB significantly when compared with control. These results suggest that FCP can be used as a soil stability enhancing agent in ASD.

Phenotypic Comparability from Genotypic Variability among Physically Structured Microbial Consortia

Microbiomes represent the collective bacteria, archaea, protist, fungi, and virus communities living in or on individual organisms that are typically multicellular eukaryotes. Such consortia have become recognized as having significant impacts on the development, health, and disease status of their hosts. Since understanding the mechanistic connections between an individual’s genetic makeup and their complete set of traits (i.e., genome to phenome) requires consideration at different levels of biological organization, this should include interactions with, and the organization of, microbial consortia. To understand microbial consortia organization, we elucidated the genetic constituents among phenotypically similar (and hypothesized functionally-analogous) layers (i.e., top orange, second orange, pink, and green layers) in the unique laminated orange cyanobacterial–bacterial crusts endemic to Hawaii’s anchialine ecosystem. High-throughput amplicon sequencing of ribosomal RNA hypervariable regions (i.e., Bacteria-specific V6 and Eukarya-biased V9) revealed microbial richness increasing by crust layer depth, with samples of a given layer more similar to different layers from the same geographic site than to their phenotypically-analogous layer from different sites. Furthermore, samples from sites on the same island were more similar to each other, regardless of which layer they originated from, than to analogous layers from another island. However, cyanobacterial and algal taxa were abundant in all surface and bottom layers, with anaerobic and chemoautotrophic taxa concentrated in the middle two layers, suggesting crust oxygenation from both above and below. Thus, the arrangement of oxygenated vs. anoxygenated niches in these orange crusts is functionally distinct relative to other laminated cyanobacterial–bacterial communities examined to date, with convergent evolution due to similar environmental conditions a likely driver for these phenotypically comparable but genetically distinct microbial consortia.

Balanced model of the folded sedimentary cover of the Greater Caucasus as a source of information about geodynamic processes on the scale of the lithosphere - statistical approach

<p>Geodynamic processes of formation of mobile belts operate during entire tectonic cycle since sedimentation up to recent uplift and erosion. In general, we can expect that some quantitative parameters of tectonic events will be associated with such processes, so they can be used to solve the inverse problem of recognizing quantity and nature of geodynamic processes.</p><p>The Greater Caucasus is a well-studied Alpine structure, within which the sedimentary cover (total thickness of 10-15 km) has a thin layering, deformed in small and moderate-sized folds. The folded structure was described in 24 detailed profiles with a total length about 500 km. Using a special method of sections balancing, models of the sedimentary cover were compiled, based on the balance of the sediments volume and the shortening values. By the method, profiles were divided into 505 "folded domains", for which their pre-folded states were restored. Then, the pre-folded domains were combined into 78 "structural cells", for which their shortening values were estimated.</p><p>For calculations, a three-stage’s conditional model of the development of the Greater Caucasus was adopted: 1) sedimentation (Jurassic-Eocene), 2) shortening and folding formation (Oligocene), 3) uplift and erosion (post-Oligocene). Six parameters were digitized in the structural cells: the depth of the basement top for development stages (1, 3, 4), the shortening value (2), the amplitude of uplift and erosion (5), the difference between the depths of the basement top in stages 3 and 1 (6). Obviously, these parameters are directly related to geodynamic processes of the Greater Caucasus formation. The calculation of the correlation matrix showed the presence of such strong correlations between a numbers of parameters, which may have a genetic sense. Factor analysis was used to clarify all these relationships. It showed the presence of two well-defined factors that explain the main dispersion of the six parameters. Factor (process) F1 (named ISOSTASY) has a weight of 46.6%, the loads on parameters 1-6 were 0.790, -0.195, 0.665, 0.982, 0.005 and 0.853. Process F1 showed the dependence of the actual depth of the basement top (4) on its first value (1), which is clearly associated with isostasy and necessarily indicates an increase of the density of the crust rocks up to mantle values. The F2 factor (named SHORTENING) has a weight of 40.2%, the loads amounted to 0.022, 0.938, -0.736, -0.158, 0.957, -0.219. Factor (process) F2 indicated the dependence of the uplift amplitude (5) on the shortening value (2), which can also be associated with isostasy and changes in the density of the crust and mantle rocks.</p><p>The calculation of the crust layer thicknesses for a part of the structure during the development, in which it has an isostatic equilibrium, showed its gradual degradation from 40 km (before a sedimentation) to 14 km after sedimentation and to present 19 km after folding and uplift (9.5 km without shortening influence).</p><p>Yakovlev F.L., Gorbatov E.S., 2018. On using the factor analysis to study the geodynamic processes of formation of the Greater Caucasus. Geodynamics & Tectonophysics 9 (3), 909–926.</p>

The Leaching of Sub-Florescent Soils as Used in the Ancient Qanat Karez Technology to Produce a Modern Cheap Solution for Controlling and Adjusting Marginal World Albedo

Huge desert endorheic basins with very substantial areas of flat evaporation pans were once in operation specifically for the precipitation of white crystalline sodium chloride. The Qanat Karez water distribution systems are thought to have been invented some 3000 years ago. Thousands of kilometers of tunnels and boreholes were designed and built with very heavy human investment, primarily to leach, dissolve and recrystallize salts - predominantly sodium chloride. They were only limited in capacity by the Qanat volumetric capacity watershed surge flow into the endorheic basins needed to extract these salts. Today we know that in addition nature has continuously supplied these basins with these rich minerals and rare earth materials, which in many cases lurk only a few meters in the water table below the basin surface. In the Tarim basin a Potash salt production unit is now pumping these brines to produce industrial Potassium fertilizer, using the Qanat Karez technology. Maintaining an industrial thin white crust layer of salt during critical hot seasons of the year over these huge desert areas and salar flats would it is calculated, increase the world albedo and enable cheap precise control of the total short/long wave reflection, in addition to the existing high albedo of the Polar Regions.

Accumulation and Release of Rare Earth Ions by Spores ofBacillusSpecies and the Location of These Ions in Spores

ABSTRACTTwo rare earth ions, Tb3+and Dy3+, were incorporated into spores ofBacillusspecies in ≤5 min at neutral pH to 100 to 200 nmol per mg of dry spores, which is equivalent to 2 to 3% of the spore dry weight. The uptake of these ions had, at most, minimal effects on spore wet heat resistance or germination, and the ions were all released upon germination, probably by complex formation with the huge depot of dipicolinic acid (DPA) released when spores germinate. Adsorbed Tb3+/Dy3+were also released by exogenous DPA within a few minutes and faster than in spore germination. The accumulation of Tb3+/Dy3+was not reduced inBacillus subtilisspores by several types of coat defects, significant modification of the spore cortex peptidoglycan structure, specific loss of components of the outer spore crust layer, or the absence of DPA in the spore core. All of these findings are consistent with Tb3+/Dy3+being accumulated in spores’ outer layers, and this was confirmed by transmission electron microscopy. However, the identity of the outer spore components binding the Tb3+/Dy3+is not clear. These findings provide new information on the adsorption of rare earth ions byBacillusspores and suggest this adsorption might have applications in capturing rare earth ions from the environment.IMPORTANCEBiosorption of rare earth ions by growing cells ofBacillusspecies has been well studied and has attracted attention for possible hydrometallurgy applications. However, the interaction of spores fromBacillusspecies with rare earth ions has not been well studied. We investigated here the adsorption and/or desorption of two rare earth ions, Tb3+and Dy3+, byBacillusspores, the location of the adsorbed ions, and the spore properties after ion accumulation. The significant adsorption of rare earth ions on the surfaces ofBacillusspores and the ions’ rapid release by a chelator could allow the development of these spores as a biosorbent to recover rare earth ions from the environment.

The Influence of Crust Layer on Reactor Pressure Vessel Failure Under Pressurized Core Meltdown Accident

The so-called in-vessel retention (IVR) was considered as a severe accident management strategy and had been certified by Nuclear Regulatory Commission (NRC) in U.S. as a standard measure for severe accident management since 1996. In the core meltdown accident, the reactor pressure vessel (RPV) integrity should be ensured during the prescribed time of 72 h. However, in traditional concept of IVR, several factors that affect the RPV failure were not considered in the structural safety assessment, including the effect of corium crust on the RPV failure. Actually, the crust strength is of significant importance in the context of a severe reactor accident in which molten core material melts through the reactor vessel and collects on the lower head (LH) of the RPV. Consequently, the RPV integrity is significantly influenced by the crust. A strong, coherent crust anchored to the RPV walls could allow the yet-molten corium to fall away from the crust as it erodes the RPV, therefore thermally decoupling the melt pool from the coolant and sharply reducing the cooling rate. Due to the thermal resistance of the crust layer, it somewhat prevents further attack of melt pool from the RPV. In the present study, the effect of crust on RPV structural behaviors was examined under multilayered crust formation conditions with consideration of detailed thermal characteristics, such as high-temperature gradient across the wall thickness. Thereafter, systematic finite element analyses and subsequent damage evaluation with varying parameters were performed on a representative RPV to figure out the possibility of high temperature induced failures with the effect of crust layer.