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The evolution of the U-Pb decay system is determined by their initial isotopic composition in the proto-Earth and the subsequent global differentiation. The differentiation is highly complicated because of large-scale evaporation and multi-stage core formation in Earth accretion. We statistically rebuild the accretional history of Earth using a series of N-body simulations. This provides us with an estimation of the amount of silicate melting and thus temperature and pressure at the bottom of the magma oceans driven by continuous planetesimal impacts. We further assumed different evolutionary paths of the redox state and found a reduced process from an oxidized state consistent with the current value of Pb content and μ value (238U/204Pb) in the bulk silicate Earth. Meanwhile, the fraction of the impactor's core that participates in the re-equilibration is around 0.2–0.7. Our model predicts the final μ value equals the observed value, 8.25, regardless of the minor contribution of the late veneer (0.2). The evolution of μ determines the growth rate of radiogenic Pb isotopes. The episodic increase of μ in multi-stage core formation accelerates the growth of radiogenic Pb isotopes (206Pb and 207Pb) and finally causes a slight deviation of the composition of Pb isotopes (206Pb/204Pb and 207Pb/204Pb) to the right of 4.567-Ga Earth Geochron. A multi-stage evolution model for U–Pb system can explain the modern terrestrial μ value, but has little influence on the puzzle of “the first Pb paradox”.

Basalts, which cover about 70% of the Earth's surface, are igneous rocks originating from cooling and solidifying the magma on the Earth's surface. Products obtained from the melting of rocks have a wide market and can be considered the precursors of glass-ceramic technology. These materials are promising due to the possibility of converting low-cost natural raw materials into products with excellent mechanical, thermal, and chemical properties. In this article, a general overview of the basic principles for obtaining basaltic glass-ceramic materials will be made, as well as their properties, applications, and potentialities.

Surface modification of different functional molecules onto NaREF4 (RE = rare earth) upconversion nanoparticles (UCNPs) impart their multiple functionalities. Functional molecules can be loaded onto NaREF4 UCNPs through the formation of coordination bonds between the surface-exposed RE3+ ions and the appropriate chemical groups of functional molecules. The density of surface RE3+ ions directly determines the loading efficiency of NaREF4 UCNPs. However, NaREF4 is a binary cation system, rendering the surface-distributed Na+ and RE3+ ions remains a mystery. Here, we develop an effective strategy to significantly enhance the density of surface RE3+ ions, thus maximizing the loading capacity of NaREF4 UCNPs. This strategy is based on a heterovalent cation exchange (HCE) reaction in the surface region in which Na+ ions are replaced by RE3+ ions. The density of surface ligands enhances from 3.6 to 8.8 molecules/nm2 after reaction, suggesting that the loading efficiency increases by approximately 150%. Benefiting from the improved loading capacity, we demonstrate such surface-RE-rich nanoparticles have the ability to offer higher colloidal stability and more desirable photodynamic therapy (PDT) efficacy. This work not only advances our understanding of cation exchange reactions in RE-based nanoparticles, but also provides significant value for considerable applications such as sensing, bioimaging, and therapy.

As part of the space experiment “Test”, a roll of cotton cloth fixed on the outer surface of the International Space Station for more than 10 years was delivered to the Earth in September 2019. The elemental composition of two fragments of the cloth, contaminated and clean, was determined using instrumental neutron activation analysis at the IBR-2 reactor. Along with 19 elements (Mg, Al, Cl, Ca, Ti, Cr, Mn, Fe, Co, Ni, Zn, Rb, Sr, Ag, Sb, Ba, Sm) determined on both fragments of the cloth, additional 20 elements (Na, Si, Sc, Cu, As, Se, Br, Mo, Zr, Cd, I, La, Ce, Eu, Ta, W, Re, Ir, Th, and U) were determined only on the contaminated fragment. The morphology of the rolled cotton cloth was characterized using Scanning Electron Microscopy. Gama and liquid beta spectroscopy were applied to measure the radioactivity of the cloth fragments. Possible sources of the determined chemical elements deposited on the cloth were discussed.

Feldspars are the most abundant minerals in the Earth’s crust, and are also important constituents of many lunar rocks and some stony meteorites. Albite (NaAlSi3O8) makes up the sodium corner of the feldspar ternary diagram (KAlSi3O8 - NaAlSi3O8 – CaAl2Si2O8) and connects the alkali-feldspar and plagioclase binary joins. Synthesis of albite, however, has long been a problem, even at high temperatures and even at high pressures when dry. In fact, most successful syntheses require the combination of high-pressure, high-temperature, and hydrothermal environments. This paper presents a sol–gel method of albite synthesis that requires hydrothermal processing followed by high-temperature recrystallization, but no high-pressure environments. This has the advantage of allowing synthesis of relatively large amounts of material and controlled elemental substitutions.

The elemental composition of the fragment of one of the biggest meteorites, which entered the Earth's atmosphere over Chelyabinsk, Russia was investigated by instrumental neutron activation analysis at the IBR-2 reactor. A total of 27 major and trace elements Si, Ti, Cr, Al, Fe, Mn, Mg, Ca, Na, K, V, Sc, Co, Ni, Zn, As, Se, Rb, Mo, Ag, Sb, Cs, Sm, Tm, Ir, Au, U was determined in the analyzed fragment. Obtained values were compared with the average composition of LL-chondrites and results reported by other scientific groups.

Based on ab initio calculations within the density functional theory and crystal structure prediction algorithms, the structure and stability of iron–nitrogen compounds in the pressure range of 100...

The Earth’s inner core comprises iron-nickel alloys with light elements. However, there is no clarity on the phase properties of these alloys. Here we show phase relations and equations of state of iron–nickel and iron–nickel–silicon alloys up to 186 gigapascals and 3090 kelvin. An ordered derivative of the body-centred cubic structure (B2) phase was observed in these alloys. Results show that nickel and silicon influence the stability field associated with the two-phase mixture of B2 and hexagonal close-packed phases under core conditions. The two-phase mixture can give the inner core density of the preliminary reference Earth model. The compressional wave velocity of the two-phase mixture under inner core conditions is consistent with that of the preliminary reference Earth model. Therefore, a mixture of B2 and hexagonal close-packed phases may exist in the inner core and accounts for the seismological properties of the inner core such as density and velocity deficits. The density and velocity of the inner core deduced from seismic observations can be explained by a two-phase mixture of ordered body-centred cubic and hexagonal close-packed phases, according to high pressure and temperature experiments

Platinum group elements are invaluable tracers for planetary accretion and differentiation and the formation of PGE sulfide deposits. Previous laboratory determinations of the sulfide liquid–basaltic melt partition coefficients of PGE (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${D}_{PGE}^{SL/SM}$$\end{document}DPGESL/SM) yielded values of 102–109, and values of >105 have been accepted by the geochemical and cosmochemical society. Here we perform measurements of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${D}_{Pt,\,Pd}^{SL/SM}$$\end{document}DPt,PdSL/SM at 1 GPa and 1,400 °C, and find that \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${D}_{Pt,\,Pd}^{SL/SM}$$\end{document}DPt,PdSL/SM increase respectively from 3,500 to 3.5 × 105 and 1,800 to 7 × 105, as the Pt and Pd concentration in the sulfide liquid increases from 60 to 21,000 ppm and 26 to 7,000 ppm, respectively, implying non-Henrian behavior of the Pt and Pd partitioning. The use of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${D}_{Pt,\,Pd}^{SL/SM}$$\end{document}DPt,PdSL/SM values of 2,000–6,000 well explains the Pt and Pd systematics of Earth’s mantle peridotites and mid-ocean ridge basalts. Our findings suggest that the behavior of PGE needs to be reevaluated when using them to trace planetary magmatic processes., Platinum group elements are used as tracers for planetary and PGE sulfide deposit formation. Here, the authors, through the measurements of Pt and Pd partition coefficients between sulfide liquid and basaltic melt, demonstrate that the partitioning of Pt and Pd does not obey Henry’s law.

The crystallization of the magma ocean resulted in the present layered structure of the Earth’s mantle. An open question is the electronic spin state of iron in bridgmanite (the most abundant mineral on Earth) crystallized from a deep magma ocean, which has been neglected in the crystallization history of the entire magma ocean. Here, we performed energy-domain synchrotron Mössbauer spectroscopy measurements on two bridgmanite samples synthesized at different pressures using the same starting material (Mg0.78Fe0.13Al0.11Si0.94O3). The obtained Mössbauer spectra showed no evidence of low-spin ferric iron (Fe3+) from the bridgmanite sample synthesized at relatively low pressure of 25 gigapascals, while that directly synthesized at a higher pressure of 80 gigapascals contained a relatively large amount. This difference ought to derive from the large kinetic barrier of Fe3+ rearranging from pseudo-dodecahedral to octahedral sites with the high-spin to low-spin transition in experiments. Our results indicate a certain amount of low-spin Fe3+ in the lower mantle bridgmanite crystallized from an ancient magma ocean. We therefore conclude that primordial bridgmanite with low-spin Fe3+ dominated the deeper part of an ancient lower mantle, which would contribute to lower mantle heterogeneity preservation and call for modification of the terrestrial mantle thermal evolution scenarios.

Constraining the core’s composition is essential for understanding Earth accretion, core formation and the sustainment of Earth’s magnetic field. Earth’s outer and inner core exhibit a density deficit relative to pure iron, attributed to the presence of substantial amounts of low atomic number ‘light’ elements, such as sulfur, silicon, oxygen, carbon and hydrogen. However, owing to its inaccessibility, estimates of core composition can only be indirectly obtained by matching results from high-pressure experiments and theoretical calculations with seismic observations. In this Review, we discuss the properties and phase relations of iron alloys under high-pressure and high-temperature conditions relevant to the Earth’s core. We synthesize mineral physics data with cosmochemical and geochemical estimates to give the likely range of compositions for the outer (Fe + 5% Ni + 1.7% S + 0–4.0% Si + 0.8–5.3% O + 0.2% C + 0–0.26% H by weight) and inner (Fe + 5% Ni + 0–1.1% S + 0–2.3% Si + 0–0.1% O + 0–1.3% C + 0–0.23% H by weight) core. While the exact composition of the core remains unknown, tighter constraints on core temperature and better connections between the solid inner core and the liquid outer core compositions will help narrow the range of potential light element compositions. Although the presence of ‘light’ elements (such as S, Si, O, C and H) can explain the core’s density deficit, the exact composition of the Earth’s core remains unknown. This Review explores the likely range of outer and inner core compositions and their implications.

Electrochemical reductions of CO2 (ECRR) and N2 (ENRR) can not only reduce CO2 emissions in the air but also make use of N2 and H2O, the most extensive resources on earth, to produce high value-added chemicals, which has become one of the hot research directions. In this study, the formation energy (Ef) and dissolution potential (Udiss) of 96 two-dimensional catalysts derived from different defect sites of monoclinic crystal boron nitride (BN) were calculated, and the catalysts with thermodynamic and electrochemical stability were selected. The suitable catalysts for producing HCOOH (Ga/In@N-BN), CO (Sn@BN), and CH3OH (Co@N-BN) by ECRR and NH3 (Fe@BN) by ENRR were predicated based on a selective calculation method. The results obtained can provide guidance for the design and development of new catalysts for ECRR and ENRR.

Carbon (C) is major element of most hot springs, yet knowledge on carbonaceous compounds in hot springs and their role in the cycle of elements are limited. Here we analyzed carbonaceous compounds in Zibo hot springs, China, by electron microscopy and chemical analysis. Results display spherical and irregular C-bearing nanoparticles from 50 to 150 nm. Nanoparticles typically contain, in wt%, 40.4–77.6 C, 8.12–15.9 N, 4.27–13.8 O, 0.12–0.13 Mg, 1.47–2.67 Si, 0.09–0.16 S, 0.04–0.20 Cl, and 0.63–34.7 Fe. These findings reveal the occurrence of C nanoparticles in hot springs, accompagnied by several other elements. The biophilic elements N and Fe and biomimetic morphology of nanoparticles suggest a biological origin. We discuss implications for carbon cycling and for the possible use of C-bearing nanoparticles to prospect geothermal resources in the deep Earth.

Earth plasters have been used as a protective coating for buildings but, due to their low strength and low resistance to weather conditions, they have been abandoned for more resistant materials which in return lack vapour permeability. Earth plasters have usually a high moisture sorption rate, and their water vapour permeability is high, allowing the transfer of humidity through the material. These properties make them an interesting material for controlling vapour movement in humid rooms. Improving their strength can be done by adding aggregates and/or fibres, but the real impact of using one type or another of fibres or aggregate is unknown. This research aims to understand the consequence of the choice of fibre or sand in the improvement of strength of plasters and the conservation of the plaster hygro-thermal properties. Properties of plasters using alternative fibres or aggregates such as wool, cow hair, pine needles, sand aimed for concrete mixes, or not properly graded sand have been compared to plasters made more traditionally with chaff fibres and mason sand.

The Maxwell–Stefan diffusion equations for multicomponent neutral gas mixtures with thermodiffusion ratios and diffusion correction factors in the Chapman–Cowling third-order approximation are derived. These thermodiffusion ratios and diffusion correction factors are presented explicitly as functions of masses, number densities, thermal conductivities, and the Chapman–Cowling collision integrals of the neutral species under consideration. Applications to the multicomponent mixture of atmospheric neutral gases O, N2, O2, He, H, Ar, H2, N, and NO are considered, and recommendations are given for using the results of this paper in studies of the Earth's atmosphere.

CO2 transports in the Earth’s interior play a crucial role in understanding the deep carbon cycle and the global climate changes. Currently, CO2 transports inside of the Earth under extreme condition of pressure and temperature have not been understood well. In this study, the molecular dynamics (MD) calculations were performed to study CO2 transports under different CO2 pressures in slit-like magnesite pores with different pore sizes at 350~2500 K and 3~50 GPa are presented. Diffusion of CO2 in magnesite was improved as the temperature increases but showed the different features as a function of pressure. The diffusion coefficients of CO2 in magnesite were found in the range of 9 × 10 − 12 m 2 s − 1 ~ 28000 × 10 − 12 m 2 s − 1 . Magnesite with the pore size of 20~25 Å corresponds to the highest transports. Anisotropic diffusion of CO2 in magnesite may help to understand the inhomogeneous distribution of carbon in the upper mantle. The time of CO2 diffusion from the mantle to Earth surface was estimated to be around several tens of Ma and has an important effect on deep carbon cycle. The simulation of CO2 transports based on the Earth condition provides new insights to revealing the deep carbon cycle in the Earth’s interiors.

The most outstanding problem militating the production of earth block in Nigeria, is the exorbitant prices of cement, rice ash replaced with cement, stabilized compressed earth block to carry load. The main objective of this study was to investigate the sustainability of earthen construction block with a partial replacement of cement using Rice Husk Ash (RHA). RHA is a bye-product material obtained from the combustion of rice husk which consists of non-crystalline silicon dioxide with high specific surface area and high pozzolanic reactivity using a set of sieves 3.35um - 63um, weigh balance, oven maintained at a temperature of 105°C and 110°C, six meta trays, a bucket, a soap, wire brushes, and a mechanical shaker. It is used as pozzolanic material in earth block. Testing specimen were determined and examine in structural composition by means of unconfined compressive strength hydraulically compressed for crushing the composition of mix with RHA content ranges from 10% to 50% to respectively. The result of the compressed earth block shows a significant resistance of shear strength of 30 to 90 kg/mm2, proving that stabilized earth block can satisfactorily carry load when structurally loaded and can resist tensile and compressive stresses.

To constrain the behavior of chalcophile (sulfide-loving) elements during arc magmatic differentiation and to understand the formation conditions of Earth’s continental crust, the partition coefficients (D) of Mn, Co, Cu, Zn, As, Se, Mo, Ag, Cd, Sn, Sb, Te, Re, Au, Pb, and Bi between monosulfide-solid-solution (MSS), Cu-rich sulfide liquid (SL; containing 11–45 wt.% Cu), and hydrous silicate melt (SM) of basaltic to dacitic compositions were determined at 1000–1200 °C, 0.5–1.0 GPa, and fO2 1–1.5 log units above the fayalite–magnetite–quartz (FMQ) buffer. The D SL / S M values are 16–160 for Co, 1100–8400 for Cu, 50–220 for Se, 1200–5900 for Ag, 50–1800 for Cd, 700–3300 for Te, 15–510 for Re, 5700–90,000 for Au, 20–440 for Pb, and 140–3300 for Bi. The D SL / S M values for Mn, Zn, As, Mo, Sn, and Sb are below 1–40. The D MSS / S M values are 55–260 for Co, 530–1700 for Cu, 74–110 for Se, 30–110 for Ag, 4–40 for Cd, 15–70 for Te, 200–5900 for Re, and 140–270 for Au. The D MSS / S M values for Mn, Zn, As, Mo, Sn, Sb, Pb, and Bi are below 1–3. The D SL / S M of Au increase with increasing Cu content of the sulfide liquid, but the D SL / S M of the other elements little affected by the Cu concentration in the sulfide liquid. Because of their distinct dissolution mechanisms in the silicate melt, the D SL / S M and D MSS / S M of Mn, Co, Zn, Cd, Sn, and Pb are mainly controlled by the silicate melt FeOtot content ([FeOtot]); the D SL / S M and D MSS / S M for Re, Mo, As, Sb, and Bi are mainly controlled by [FeOtot] and fO2; the D SL / S M and D MSS / S M for Cu, Ag, and Au are mainly controlled by [FeOtot] and the content of reduced sulfur in the silicate melt; and the D SL / S M and D MSS / S M for Se and Te are mainly controlled by fO2. Using all available D SL / S M and D MSS / S M data, a partitioning model was developed for predicting D SL / S M and D MSS / S M of chalcophile elements as a multi-function of temperature, pressure, fO2, and silicate melt and sulfide compositions. Sulfide phase relations suggest that the sulfides precipitating from arc magmas containing >100 µg/g Cu in the silicate melt occur as Cu-rich sulfide liquid, whereas the sulfides precipitating from arc magmas containing 30–70 µg/g Cu in the silicate melt occur as mixed MSS and Cu-rich sulfide liquid. Modeling the Cu evolution trends of global arc magmas illustrates that the precipitating sulfides are dominantly MSS in continental arcs with a crustal thickness of >30 km, with the proportion of sulfide liquid being less than 20%; whereas, in island arcs with a crustal thickness of

Astrophysical surveys so far have suggested that water-rich planets could be common [1] (including Uranus and Neptune in our Solar System). In the conventional interior model of water-rich planets, it has been assumed to have separate layers of atmosphere, ice/fluid, rocky mantle and metallic core [2]. However, recent studies have proposed the existence of heavy elements in the ice/fluid layer of Uranus, challenging the conventional view [3]. In addition, chemical interaction and thermodynamic processes of major rock-forming minerals at the H2O–rock interface conditions of the water-rich planetary interiors have been scarcely explored. We have performed laser-heated diamond-anvil cell experiments on two rock-forming minerals, olivine ((Mg0.9,Fe0.1)2SiO4) and ferropericlase ((Mg0.9,Fe0.1)O), in water at the pressure and temperature conditions expected for the water-rich planets. During laser-heating, we collected X-ray diffraction (XRD) data at beamlines 13-IDD of GSECARS at APS and P02.2, the ECB of PETRA III at DESY. Our dataset covers pressures between 20 and 80 GPa. After high-pressure and high-temperature experiments, we conducted chemical and textural analysis using focused ion beam (FIB) and scanning electron microscope (SEM) at Yonsei University. During laser-heating, Si-rich high-pressure phases were formed, such as bridgmanite ((Mg,Fe)SiO3) and stishovite (SiO2), from the high Mg/Si ratio of starting composition (olivine). The formation of Si-rich phases from Mg-rich starting composition suggests dissolve of MgO into H2O-liquid during laser-heating at high-pressures. This was also found for (Mg0.9,Fe0.1)O ferropericlase starting material. The intensity of the diffraction peak of ferropericlase was dramatically decreased at high-pressure and high-temperature conditions, which indicates that (Mg0.9,Fe0.1)O is soluble in H2O-liquid. From chemical analysis, we found the dome-like structures, which showed that domes are Mg-rich and below the domes is Si-rich. Between Mg-rich and Si-rich regions, porous structures (almost empty) were positioned, meaning that MgO-rich fluid existed at high-pressure and high-temperature conditions. In summary, the textural and chemical analysis combined with XRD data indicates a selective leaching of MgO preferentially from silicate during laser heating, making MgO-dissolved in high-temperature fluid, which peaks between 20 and 40 GPa and above 1,500 K [4]. For water-rich planets with 1–6 Earth masses, the chemical reaction at the deep H2O–rock interface would lead to high concentrations of MgO in the H2O layer. For Uranus and Neptune, our experiments indicate that the top ~3% of the H2O layer of them, the pressure and temperature conditions of which have been achieved in this study, would have a large storage capacity for MgO. If an early dynamic process enables the H2O–rock reaction, the topmost H2O layer may be rich in MgO, possibly affecting the thermal history of the planet. [1] Batalha, N. M. Proc. Natl Acad. Sci. USA 111, 12647–12654 (2014). [2] Guillot, T. Annu. Rev. Earth Planet. Sci. 33, 493–530 (2005). [3] Helled, R., Nettelmann, N. & Guillot, T. Space Sci. Rev. 216, 38 (2020). [4] Kim, T. et al. Nat. Astron. (2021).

The natural abundance of potassium in the earth’s crust is 1000 times higher than that of lithium, so energy technologies built on potassium are more sustainable. Potassium-ion batteries have attra...

Investigations of ramp-induced shock-wave boundary-layer interaction have been carried out for real gas flows of air and carbon dioxide through hypersonic laminar flow simulations corresponding to Earth and Mars atmospheres. An in-house-developed solver, which accounts for the real gas effects, has been employed for these studies. Effects of various parameters like wall temperature, freestream stagnation enthalpy, freestream Mach number, and blunt leading edge are explored on the intensity of shock-wave boundary-layer interaction (SWBLI). In either case, an increase in separation length is observed with an increase in wall temperature and a decrease in Mach number as well as freestream stagnation enthalpy. Here, the intensity of alteration is always noted to have a higher percentage for the Mars gas model. Further, separation length is found to be almost equal for the same wall to total temperature ratio in both of the flow mediums. The present study also affirms the fact that the leading edge bluntness can be used as a tool to reduce the size of the separation region in these planetary atmospheres. Revised correlations have been proposed for hypersonic Earth atmospheric flow with real gas effects to predict the extent of upstream influence and separation bubble size. The outcomes of simulations have also helped to device new correlations for these flow features of SWBLI for Mars atmospheric conditions. In all, the need for consideration of real gas effects and an exclusive real gas flow solver for the Mars atmosphere are the prominent recommendations of current studies.

Remnant extraterrestrial chrome spinels from terrestrial sediments provide information on how the mixture of meteoritic materials falling to Earth has changed over Earth’s history. The parent meteorite type of each grain can be identified by characteristic elemental and oxygen-isotope abundances. Some meteorite types can be difficult to classify because their chrome-spinel compositional ranges overlap. Silicate inclusions within chrome spinels of modern ordinary chondrites have been shown to have discriminating power among meteorite subclasses. We employed energy-dispersive X-ray spectroscopy in a scanning electron microscope (SEM) and in a (scanning) transmission electron microscope (S/TEM) to investigate inclusions in chrome-spinel grains from Ordovician and Jurassic sediments. Unaltered Ordovician inclusions allowed us to establish the size limits for reliable SEM analysis of inclusions. The Jurassic grains were more altered, but the use of STEM techniques on small inclusions (

Nanosilica was prepared from sugarcane bagasse ash (SCBA) and used as additive to the diatomaceous earth (DE). Nanosilica was characterized using laser light scattering (LS), scanning electron micr...

Silicon, the second most abundant element on earth, has been an ideal candidate for semiconductor industry. Recently, it was shown that a superconducting phase with a large critical temperature Tc ...

Existing notions on the distribution of carbon on the Earth have been considered in the article. By the example of the data on carbon content in the upper mantle of the Earth obtained in the west of the USA by deep seismic tomography method the appraisal of the resource potential of the interior has been made within the limits of the theory of the deep abiogenous-mantle origin of oil and gas. According to the given appraisal, the partly melted zone (reservoir) contains not less than 1.2·1017 kg of volatiles (Q, kg), such as H or C. Calculation by carbon (С) taking into account the initial data demonstrated that the weight content (concentration) of carbon per unit volume of the Earth crust and upper mantle for which the appraisals of carbon content were completed will be 1 333.3 kg/m3 or 1.3 t/m3 (1.3 g/cm3). With average amount of melt of the rocks of the upper mantle 0.5±0.2 % (per volume), the volume of the area of melting of the Earth crust (deep carbon reservoir), containing the appraised volume of volatiles, will be: 4.5·1011 m3. In such a notion the weight content (concentration) of carbon per unit volume of partly melted zone of deep carbon reservoir will be: 2.67·105 kg/m3 or 266.67 t/m3 (266.67 g/cm3). These are very high figures if not to say fantastically high, characterizing not only high content of carbon and hydrogen as the main donors of hydrocarbons but also characterizing concentration of these elements within definite zones of the upper mantle of the Earth (asthenospheric layer) by all components (composition, concentration, phase state, PT-conditions), which is referred by our opinion to the sources of deep oil and gas formation. The data presented allow us to affirm that the problem of donors of HC of deep, abiogenous-mantle genesis has been resolved in our concept, and the source has been determined with high probability of the primary donors of HC in the section of the mantle and iron-carbon core of the Earth having inexhaustible resources of primary carbon, with its phase composition depending on PT conditions of the terrestrial envelopes might be crystalline (diamond phase, iron and nickel compounds (Fen+Nin)+Cn, iron carbides, for example — FeC, Fe2C, Fe3C (cementite) et al.), liquid (for example, the melt with admixture of sulfur and other volatiles H-N-F-O-Cl) and gaseous (СО2 gaseous only in the mantle, higher than D″ layer). In this case HC synthesis in industrial volumes is realized in the process of hydrogenation of deep carbon on the ascending hydrogen streams within the limits of asthenospheric lenses favoured by the presence of reaction volume here, catalysts and the necessary PT-conditions for polymerization of hydrocarbon radicals.

Toprak işleme makinaları sürüm işlemi yaparken, işleyici parçalar ile toprakta bulunan kuvars veya korundun gibi partiküller sürtünmektedir ve bu durum toprakta sürüm yapan işleyici tarım ekipmanlarında aşınmalara neden olmaktadır. Ülkemizde, bu ekipmanların mekanik özelliklerinin iyileştirilmesi ve aşınmaya karşı dirençlerini artırabilmek amacıyla uygulanan sertleştirme ısıl işlemleri gelişen teknikler ile birlikte değişmektedir. Yapılan çalışmada süneklik ve tokluk değerlerinin yüksek olduğu bilinen ve tarım aletlerinin belli bölümlerinde sıklıkla kullanılan 60SiMn5 alaşımına sertleştirme işleminden sonra farklı sıcaklıklarda (250 °C ve 270 °C) uygulanan menevişleme işlemlerinin mikroyapı ve mekanik özelliklerine etkileri incelenmiştir. Bu amaçla, 970 °C’ de östenitleştirme ve ardından yağda soğutma işlemi uygulandıktan sonra farklı sıcaklıklarda menevişleme işlemi uygulanmıştır. Uygulanan menevişleme işlemlerinin mikroyapıya etkisi optik mikroskop ve SEM-EDX analizleri ile gerçekleştirilmiştir. Numunelerin sertlik, darbe ve kuru kum kauçuk aşınma testleri gerçekleştirilmiştir. Çalışmanın sonucunda 270 °C’ de yapılan menevişleme işlemi ile numunede alt beynit yapısının daha homojen dağılmasının sağlaması sebebi ile malzemenin tokluk değerinde artış görülmüştür. Ayrıca uygulanan menevişleme işlemlerinin akma, çekme ve aşınma dayanımlarını arttırdığı ve mekanik özellikleri olumlu yönde etkilediği gözlemlenmiştir.

The paper presents author’s original and literature data on the standard free energy of 31 Sc ions and complexes in aqueous solution. Scandium behavior at the weathering of phyllite shales is physicochemically simulated with the Selector program package. The content of Sc in the shales is close to its average content in the Earth’s crust: 10–3 wt %. Solution in the weathering profile was determined to contain Sc practically only in the form of the hydroxocomplex $${\text{Sc}}({\text{OH}})_{3}^{0}.$$ The dissolved Sc concentrations is controlled by the solubility of its oxide Sc2O3 and phosphate ScPO4 and is lower than 10–9 mol/L.

The target bodies of C‐complex asteroid sample return missions are carbonaceous chondrite‐like near‐Earth asteroids (NEAs), chosen for the abundance and scientific importance of their organic compounds and “hydrous” (including hydroxylated) minerals, such as serpentine‐group phyllosilicates. Science objectives include returning samples of pristine carbonaceous regolith from asteroids for study of the nature, history, and distribution of its constituent minerals, organic material, and other volatiles. Heating after the natural aqueous alteration that formed the abundant phyllosilicates in CM and similar carbonaceous chondrites dehydroxylated them and altered or decomposed other volumetrically minor constituents (e.g., carbonates, sulfides, organic molecules; Tonui et al. 2003, 2014). We propose a peak‐temperature thermometer based on dehydroxylation as measured by analytical totals from electron probe microanalysis (EPMA) of matrices in a number of heated and aqueously altered (but not further heated) CM chondrites. Some CM lithologies in Maribo and Sutter’s Mill do not exhibit the matrix dehydroxylation expected for surface temperatures expected from insolation of meteoroids with their known orbital perihelia. This suggests that insolated‐heated meteoroid surfaces were lost by ablation during passage through Earth’s atmosphere, and that insolation‐heated material is more likely to be encountered among returned asteroid regolith samples than in meteorites. More generally, several published lines of evidence suggest that episodic heating of some CM material, most likely by impacts, continued intermittently and locally up to billions of years after assembly and early heating of ancestral CM chondrite bodies. Mission spectroscopic measures of hydration can be used to estimate the extent of dehydroxylation, and the new dehydroxylation thermometer can be used directly to select fragments of returned samples most likely to contain less thermally altered inventories of primitive organic molecules.

A way of calculating the field of solar radiation in Earth’s atmosphere is described that considers the thermodynamic non-equilibrium in the vibrational bands of CO2 and O3. The proposed technique allows calculations with high spectral resolution (line by line), along with parameterizations of the optical parameters of the Earth’s upper atmosphere that can be used in calculating the field of solar radiation.

Evaporative loss of sulfur from molten planetesimals can explain the sub-chondritic sulfur isotope composition of the bulk silicate mantle, suggesting an important role for planetesimal evaporation in establishing Earth’s volatile budget.

Fluorite structured materials have shown their applicability in various fields both on and off Earth. In particular, these oxides find extensive application in nuclear energy and the use of actinid...

Despite being the most ubiquitous compound on Earth, the fundamental properties of water are not fully understood, especially in nanoconfinement. Densely grafted polyelectrolyte (PE) molecules atta...

The incorporation of water in nominally anhydrous minerals plays a crucial role in many geodynamic processes and evolution of the Earth and affects the physical and chemical properties of the main constituents of the Earth's mantle. Technological advances now allow the transport properties of minerals to be precisely measured under extreme conditions of pressure and temperature (P and T) that closely mimic the P–T conditions throughout much of the Earth's interior. This contribution provides an overview of the recent progress in the experimental studies on the influence of water on physical properties (i.e., diffusivity, electrical conductivity, thermal conductivity, sound velocity, and rheology) of olivine, wadsleyite, and ringwoodite together with their applications. In particular, consistency among various experimental data is investigated, discrepancies are evaluated, and confusions are clarified. With such progress in the experimental determination of transport properties of major mantle minerals, we can expect new insights into a broad range of geoscience problems. Many unresolved issues around water inside Earth require an integrated approach and concerted efforts from multiple disciplines.

The electrical conduction mechanism of the hydrous minerals under high pressure is of great significance for understanding the high conductivity of the mantle and the Earth’s internal water. Theref...

Kesterite-based thin-film solar cells (TFSCs) have recently gained significant attention in the photovoltaic (PV) sector for their elemental earth abundance and low toxicity. An inclusive study fro...

In this work, we study the depth of a buried current electrode that constitutes an effect on the electric potential in a transition multilayer earth. A three-layered earth model is applied to simul...

A simple, cost-effective, do-it-yourself earth field nuclear magnetic resonance spectrometer with shimming is demonstrated. A spectrometer for understanding magnetic resonance physics in an academic environment is presented here along with its coil and system component design. This system was designed with inexpensive and readily available electronic components costing less than US $130. The three signal chains in the system include the polarizer along with the polarization coil, transmitter driver with transceiver coil, and receiver circuit serving as a low-noise amplifier. A microcontroller acting as the signal generator and processor controls the entire system. Switching between the transmitter and the receiver is via a relay circuit. In experiments, the free induction decay obtained from the water sample lasted 2 s with an amplitude of 5 a.u. at 1512 Hz. The line width decreased by 13 Hz after active shimming compared to 3 Hz with passive shimming. The spin echo results of the commercially available Terranova-MRI system with and without sample were used as a benchmark for the low-cost earth field nuclear magnetic resonance spectrometer. The entire system had to be fine-tuned to visualize the free induction decay because the 1.2 kHz and 50 Hz noise was predominant before tuning. Future work will involve the incorporation of gradients and time-shared pulse sequence design.

Iron is one of the most abundant elements on the surface of the earth (5.1%), but is rarely used for photocatalytic hydrogen production due to its unsuitable band structure. Herein, a ternary Z-scheme g-C3N4/rGO/FeOOH heterostructure photocatalyst for hydrogen production was designed and fabricated. Due to its narrow bandgap and a low oxygen evolution overpotential of FeOOH, the Z-scheme g-C3N4/rGO/FeOOH ternary heterojunction exhibited excellent photocatalytic hydrogen production with the yields of 124.9 and 869.8 μmol h−1 g−1 (244.9 and 107.4 times larger than that of pristine g-C3N4) under visible and UV-visible light irradiation, respectively. This work could expand the usage of the earth-abundant element for solar energy conversion and provide a new viewpoint for the development of high-performance photocatalysts through a rational design of the component of the heterostructure.

High energy density magnets are preferred over induction magnets for many applications, including electric motors used in flying rovers, electric vehicles, and wind turbines. However, several issues related to cost and supply with state-of-the-art rare-earth-based magnets necessitate development of high-flux magnets containing low-cost earth-abundant materials. Here, by using first-principles density functional theory, we demonstrate the possibility of tuning magnetization and magnetocrystalline anisotropy of one of the candidate materials, MnBi, by alloying it with foreign elements. By using density functional theory in the high-throughput fashion, we consider the possibility of various metal and non-metal elements in the periodic table occupying empty sites of MnBi and found that MnBi-based alloys with Rh, Pd, Li, and O are stable against decomposition to constituent elements and have larger magnetization energy product compared to MnBi. Combined with other favorable properties of MnBi, such as high Curie temperature and earth abundancy of constituent elements, we envision the possibility of MnBi-based high-energy-density magnets.

The procedure of accelerated resource tests of spacecraft polymers for their resistance to the long-term influence of atomic oxygen (AO) in the Earth's ionosphere at altitudes from 200 to 700 km has been developed. The procedure involves irradiation of polymers with high-energy ions of atomic oxygen and the use of a kapton-H polyimide as reference material. The condition of equivalence of the " atomic oxygen - polymer" interaction in the ionosphere and on the laboratory set is the equality of tested material mass loss. The basis for substantiating the procedure of accelerated tests is the result: when irradiating the kapton-H polymer with high-energy atomic oxygen ions in the energy range from 30 to 80 eV, the degradation of polyimide is determined by the process of chemical etching of the material. To substantiate the procedure of accelerating resource tests of polymeric structural materials of spacecraft for resistance to long-term action of atomic oxygen flows, the dependences of mass loss and volumetric mass loss factor (reactivity) of kapton-H polyimide and Teflon FEP-100A on fluence and energy of the atomic oxygen ions have been obtained. It is shown that when irradiating kapton-H polyimide with atomic oxygen ions with the energy of 30 to 80 eV, the material mass loss due to chemical etching is about an order of magnitude greater than the mass loss due to kinetic sputtering. When the kapton-H polymer is irradiated with high-energy atomic oxygen ions, the coefficient of acceleration of the resource tests and the fluence of atomic oxygen are about two orders of magnitude greater than the coefficient of acceleration obtained using atomic oxygen ions with an energy of 5 eV.