Mo System Research Articles

Valuing the synergy in the water-energy-food nexus for cropping systems: a case in the North China Plain

Extreme climate change, rapid population growth and economic development drive a growing demand for resources, which lead to energy, food, water and their intertwined nexus becoming increasingly important. Agricultural decisions considering the interconnections among water, energy, and food are critical. The consumption of large amounts groundwater and non-renewable energy by the predominant traditional wheat-maize cropping system has caused a serious water shortage in the North China Plain (NCP), which is a large food production region in China. This situation has strained the relationship between water/energy consumption and food production. It is important to seek synergy in the water-energy-food nexus. This paper proposed a relative index of water-energy-food (WEFRI) based on different values of resource consumption and use efficiency between treatment systems and control system to analyze the synergy between water utilization, energy consumption and food supply in different cropping systems at the field scale. The goal is to seek a sustainable cropping system to balance crop production while reducing energy consumption and water depletion. In this case, different systems including monocropped maize (Zea mays) (MM), intercropped maize and soybean (Glycine max) (MS), relay cropped of maize with pea (Pisum sativum) (MP) and potato (Solanum tuberosum) (MO), rotation of maize with spinach (Spinacia oleracea) (MI) and ryegrass (Secale cereale) (MR), and using traditional wheat-maize (Triticum aestivum) (MW) as a control. MM, MS, MP and MO were the best systems within a particular range of food supply reduction. The WEFRI of the MM/MS system was the highest (2.96/2.78). Compared to the MW system, the groundwater consumption of MM/MS was reduced by 73.84%/73.84%, and non-renewable energy inputs were reduced by 48.01%/48.30%; however, the food supply decreased by 48.05%/51.70%. The WEFRI of the MP system was 1.98. In comparison with the MW system, the groundwater consumption of the MP system was reduced by 28.46%, and the non-renewable energy inputs were reduced by 42.68%. However, the food supply decreased by 37.13%. The WEFRI of MO system was 1.92. Compared to the MW system, the groundwater consumption of MO was reduced by 11.47%, non-renewable energy inputs were reduced by 32.14%, and the food supply only decreased by 26.27%. In conclusion, we theoretically proposed the following references for cropping systems in the NCP: MM and MS are implemented when the areas has extreme water shortages, MO is implemented when a less than 30% reduction in the food supply capacity is acceptable, and MP is recommended if a 30%–40% reduction in the food supply is acceptable.

New insights into sub-barrier fusion of 28Si + 100Mo

Fusion cross sections of the 28Si + 100Mo system have been measured near and below the Coulomb barrier by detecting the evaporation residues at forward angles. The excitation function has an overall smoother trend than what obtained in a previous experiment, and a large discrepancy is found for the lowest-energy region, where we observe a tendency of the S factor to develop a maximum, which would be a clear indication of hindrance. The results have been compared with the theoretical prediction of coupled-channels calculations using a Woods–Saxon nuclear potential, and including the low-energy excitation modes of both nuclei. Good agreement with data is found by including, in the coupling scheme, the three lowest members of the ground state rotational band of the oblate deformed 28Si, and two-phonons of the strong quadrupole vibration of 100Mo. The additional coupling, in a schematic way, of the two-neutron pick-up between ground states (Q-value = +4.86 MeV) has a minor effect on calculated cross sections, and does not essentially improve the data fit. The excitation function of 28Si + 100Mo has been compared with that of (1) the heavier system 60Ni + 100Mo having analogous features, and (2) several near-by 28Si, 32S + Zr, Mo systems with various nuclear structures and transfer Q-values. The role of quadrupole and octupole excitation modes, as well as of transfer channels, in affecting the fusion dynamics, are clarified to some extent. Systematic measurements of fusion barrier distributions and CC calculations properly including transfer couplings, are necessary, in order to shed full light on the influence of the various coupled channels on the fusion cross sections.

Subduction: The recycling engine room for global metallogeny

The formation of ore deposits, within mineral systems that represent highly anomalous concentrations of economic elements in localized parts of the Earth’s crust, first requires an enriched and available source of those elements. In early Earth history, initial enrichment in the upper mantle was arguably through mantle plumes that even recycled metals from the core-mantle boundary. From the Mesoarchean onwards, the development of plate tectonics allowed subduction processes to be increasingly important in both recycling of elements from the upper mantle into the lower crust and from there into the upper crust where mineral deposits could form and be exploited. The most obvious expression of this recycling process is the direct association of porphyry-high-sulfidation epithermal-skarn Cu-Au-Ag +/- Mo systems and inboard fractionated granite-associated Sn-W systems with magmatic-hydrothermal fluids derived from subduction-related magmas in convergent margins, where epithermal Au-Ag systems also developed due to high thermal gradients. Syn-subduction VMS Cu-Zn-Pb(Au) systems were accreted at convergent margins. Most orogenic gold systems relate to fluids released through devolatilization of down-going subduction slabs and overlying metal-rich sediment wedges. More indirect associations relate to the ability of subduction zones to cause structural damage and metasomatize and fertilize sub-continental mantle lithosphere along the margins of bordering craton margins. Orogen collapse in the final stages of the subduction-related orogenic event led to asthenosphere upwelling and formation of proximal intrusion-related and more distal Carlin-type gold systems in continental basins on the craton margins. During subsequent orogenic events, previously metasomatized and fertilized mantle lithosphere was reactivated to release hydrothermal fluids to form many of the orogenic gold systems in eastern China. Reactivation of the metasomatized lithosphere also resulted in development of post-subduction hybrid or alkaline magmas that generated giant magmatic Kiruna-type Fe-P, carbonatite-related REE-Nb or Cu-P, and lamproite-related diamond systems, together with magmatic-hydrothermal IOCG mineral systems near craton margins. Subduction-damaged craton margins and their rift-related marginal basins became the sites of formation of Zambian Copper Belt-type deposits and the craton margins were reactivated during subsequent rifting allowing intrusion of giant Ni-Cu mafic–ultramafic bodies along lithosphere-tapping fault zones at those margins. Thus, subduction acts as the recycling engine room or factory responsible for many of the global giant mineral systems that are currently exploited.

Structure Formation and Mechanical Characteristics of Dispersion-Hardening Alloy Based on Ni–Cr–Nb–Mo System

Structure Formation and Mechanical Characteristics of Dispersion-Hardening Alloy Based on Ni–Cr–Nb–Mo System

A CALPHAD-type Young's modulus database of Ti-rich Ti–Nb–Zr–Mo system

Accurate Young's modulus is the necessity for the design of biomedical Ti alloys. A combinatorial method of the diffusion couple, nanoindentation, electron probe microanalysis (EPMA), and CALculation of PHAse Diagrams (CALPHAD) techniques has been utilized to construct the Young's modulus database of Ti alloys with various compositions in the present work. Two groups of body-centered cubic (bcc) Ti–Nb–Zr–Mo quaternary diffusion couples annealed at 1273 K for 25 h were experimentally prepared. Subsequently, the composition-dependent mechanical properties in the wide compositional range of Ti-based alloys were obtained by using EPMA and nanoindentation probes. Finally, on the basis of the measured Young's moduli in the present and previous work and the modeling parameters of Young's modulus of Ti–Nb–Zr system, the Young's modulus database of bcc Ti–Nb–Zr–Mo system was established through the CALPHAD approach. The CALPHAD-type database of bcc Ti–Nb–Zr–Mo system can provide the accurate Young's moduli of Ti alloys with wide compositions.

Geology and petrogenesis of the Sungun deposits: Implications for the genesis of porphyry-type mineralisation in the NW Urumieh–Dokhtar magmatic Arc, Iran

The Miocene Sungun porphyry Cu–Mo systems, located in Azerbaijan belt, NW Iran, is associated with the high-Sr/Y magmas, which were engendered in a post-collisional setting. However, the petrogenesis of these fertile magmas and their mineralisation are still unknown. In this study, we present whole-rock major-trace elements, zircon U–Pb dating and the Lu–Hf isotopes in the ore-forming porphyries of the Sungun porphyry systems. The corresponding results showed that the samples were rich in large-ion lithophile elements and poor in high-field-strength elements; moreover, they presented both high K2O (2.4–3.5 wt%) and Sr (727–770 ppm) and low Y (11–14 ppm) contents. The zircon U–Pb age of the Sungun porphyry was ~19 Ma, with positive εHf(t) ratios (5.5–11.8) and young TDM2 ages between 322 and 705 Ma. Additionally, the Sungun high-Sr/Y porphyries contained anhydrites (CaSO4); and had high zircon Ce4+/Ce3+ ratios (33–728), relatively low zircon saturation temperatures (620–804 °C), and plagioclases with excess Al content. Overall, these evidences suggest that a water-fluxed melting of the subduction-modified juvenile lower crust might have generated a high oxygen fugacity, leading to the formation of the hydrous and S-rich Sungun fertile magmas in the NW Urumieh–Dokhtar magmatic Arc.

The Geology, Geochemistry, and Origin of the Porphyry Cu-Au-(Mo) System at Vathi, Serbo-Macedonian Massif, Greece

The Vathi porphyry Cu-Au ± Mo mineralization is located in the Serbo-Macedonian metallogenic province of the Western Tethyan Metallogenic Belt. It is mainly hosted by a latite and is genetically associated with a quartz monzonite intrusion, which intruded the basement rocks of the Vertiskos Unit and the latite, 18 to 17 Ma ago. A phreatic breccia crosscuts the latite. The quartz monzonite was affected by potassic alteration, whereas the latite was subjected to local propylitic alteration. Both styles of alteration were subsequently overprinted by intense sericitic alteration. M-type and A-type veins are spatially associated with potassic alteration, whereas D-type veins are related to the sericitic alteration. Three ore assemblages are associated with the porphyry stage: (1) pyrite + chalcopyrite + bornite + molybdenite + magnetite associated with potassic alteration; (2) pyrite + chalcopyrite related to propylitic alteration; and (3) pyrite + chalcopyrite + native gold ± tetradymite associated with sericitic alteration. A fourth assemblage consisting of sphalerite + galena + arsenopyrite + pyrrhotite + pyrite ± stibnite ± tennantite is related to an epithermal overprint. Fluid inclusion data indicate that the A-type veins and related porphyry-style mineralization formed at 390–540 °C and pressures of up to 646 bars (<2.6 km depth) from boiling hydrothermal fluids. A later condensation of vapor-rich inclusions resulted in a moderately saline fluid (8.4–11.2 wt % NaCl equiv) at temperatures between 311 and 392 °C, which were related to sericitic alteration, D-type veins, and associated metallic mineralization. Subsequent dilution of the moderately saline fluid at lower temperatures (205–259 °C) produced a less saline (1.4–2.9 wt % NaCl equiv.) fluid, which is likely associated with the late epithermal overprint.

Influence of Heat Treatment on the Microstructure and Physicomechanical Properties of Titanium Alloys of the Ti−Nb−Mo system

Influence of Heat Treatment on the Microstructure and Physicomechanical Properties of Titanium Alloys of the Ti−Nb−Mo system

Interligand communication in a metal mediated LL'CT system - a case study.

A series of oxo-Mo(iv) complexes, [MoO(Dt2−)(Dt0)] (where Dt2− = benzene-1,2-dithiol (bdt), toluene-3,4-dithiol (tdt), quinoxaline-2,3-dithiol (qdt), or 3,6-dichloro-benzene-1,2-dithiol (bdtCl2); Dt0 = N,N′-dimethylpiperazine-2,3-dithione (Me2Dt0) or N,N′-diisopropylpiperazine-2,3-dithione (iPr2Dt0)), possessing a fully oxidized and a fully reduced dithiolene ligand have been synthesized and characterized. The assigned oxidation states of coordinated dithiolene ligands are supported with spectral and crystallographic data. The molecular structure of [MoO(tdt)(iPr2Dt0)] (6) demonstrates a large ligand fold angle of 62.6° along the S⋯S vector of the Dt0 ligand. The electronic structure of this system is probed by density functional theory (DFT) calculations. The HOMO is largely localized on the Dt2− ligand while virtual orbitals are mostly Mo and Dt0 in character. Modeling the electronic spectrum of 6 with time dependent (TD) DFT calculations attributes the intense low energy transition at ∼18 000 cm−1 to a ligand-to-ligand charge transfer (LL′CT). The electron density difference map (EDDM) for the low energy transition depicts the electron rich Dt2− ligand donating charge density to the redox-active orbitals of the electron deficient Dt0 ligand. Electronic communication between dithiolene ligands is facilitated by a Mo-monooxo center and distortion about its primary coordination sphere.

Development of n-body interatomic potentials for calculating the thermodynamic characteristics of V-Nb-Mo-W alloys

New interatomic potentials for Mo and binary systems V-Nb, V-Mo, Nb-Mo, Nb-W and Mo-W are constructed taking into account the angular dependencies of interatomic interactions. Together with the potentials constructed earlier in the same approach, a complete set of potentials for modeling alloys of the V-Nb-Mo-W system at any component concentrations is obtained. A tendency to narrow the range of values of the calculated enthalpy of formation and the volume of formation in equiatomic alloys of the V-Nb-Mo-W system with an increase in the number of components was found. Deviations from the Vegard’s rule in the volume of formation of these alloys are shifted to the negative range of values when the number of components is more than two.

Features of Deformation of High-Alloy Heat-Resistant Nickel Alloys near the Complete Dissolution Temperature of the Strengthening γ' Phase

The features of deformation of high-alloy heat-resistant nickel alloys for disks of gas turbine engines of the Ni–Co–Cr–W–Al–Nb–Ti–Mo system (EP962, EK151, and EP975 type) have been studied near the temperature of complete dissolution of the strengthening γ' phase. Analysis of the deformation curves has shown that the softening processes are controlled by dynamic recrystallization, and the greatest decrease in the flow stress in the two-phase region is observed at a temperature of ~20°C below the complete dissolution of the γ' phase, which is associated with the presence of ~10% of γ' particles larger than 1.5 μm.

Thermodynamic re-optimizations of the Ru–X (X=Al, Hf, Mo, Ti) binary systems

The Ru–X (X = Al, Hf, Mo, Ti) systems were re-optimized by means of the CALPHAD method according to the experimental phase equilibria and thermochemical data, as well as updated Gibbs energy function of “GBCCRU” in SGTE Pure 5 database. The substitutional solution model was applied to the phases liquid, fcc_A1, bcc_A2 and hcp_A3. Besides, the phases Al6Ru, Al13Ru4, Al5Ru2, Al2Ru and Al3Ru2 in the Ru–Al system were modeled as stoichiometric compounds and the phase Mo5Ru3 (σ) in the Ru–Mo system was described as (Mo,Ru)10(Mo,Ru)20 and (Mo,Ru)10(Mo,Ru)4(Mo,Ru)16 using the two-sublattice and three-sublattice models, respectively. The phases AlRu, HfRu and RuTi with the bcc_B2 crystal structure were treated as the ordered ones of bcc_A2. The reliable thermodynamic parameters of these binary systems were obtained, which could be used as the basis for thermodynamic calculations of high-order systems and database establishment of Ni-based superalloys.

The Paleoproterozoic porphyry copper–molybdenum deposit of Kourki (Liptako Province, western Niger)

Abstract The Kourki porphyry Cu–Mo deposit is located in the southern part of the Gorouol greenstone belt in Western Niger. The potential Cu–Mo mineralization is hosted by granitoids (granodiorite and diorite) and veins, in Paleoproterozoic plutonic rocks, which are the main porphyry Cu–Mo system. The scientific objective of this study was to determine the characteristics of Kourki Cu–Mo mineralization and to compare them with other porphyry systems in the world and particularly with those of the West African Craton. The methods implemented consist of a field study and a polarizing microscope analysis in transmitted and reflected light on the rocks bearing Cu–Mo mineralization. The use of reference diagrams made it possible, on the one hand, to confirm the origin of the Cu–Mo mineralization and, on the other hand, to specify conditions of the formation of this mineralization. The geology of the study area shows a granodiorite–tonalite pluton in close contact with dioritic intrusions to the north, clastic sediments to the east, and volcano-sedimentary rocks to the SE. The pluton is crosscut by an intrusion of molybdenum porphyry dyke with irregular shape that can be observed in outcrop. The geochemical study shows that the granodiorite–tonalite pluton can be related to a calc-alkaline plutonic series which characterizes an arc type environment. Large areas of hydrothermal quartz breccia have been identified within the pluton. They were set up by hydraulic fracturing along the zones of weakness. Most of the Cu–Mo mineralization in the Kourki deposit occurs as hydrothermal breccia, filled with veins, and was disseminated in the porphyry diorite and quartz–diorite stockworks. The mineralogical assemblage is marked by a predominance of pyrite, molybdenite, chalcopyrite and quartz with some bornite and chalcocite. The alterations include potassic alteration, propylitic alteration, sericitization and epidotization. All of these data show that the Kourki porphyry represents a characteristic system of an environmental arc, quite comparable with that of the Andean Cordillera.

Crystallographic Textures of Strain and Recrystallization in a Superalloy of the Ni – Cr – Mo System

The method of orientation microscopy (EBSD) is used to study the structural and textural states of a nickel-base Ni – Cr – Mo alloy after cold rolling and subsequent annealing. It is shown that the deformation yields a multicomponent rolling texture. The Σ3 special boundary formed at the start of the deformation process is preserved after the deformation as a stable-energy object. Recrystallization yields a crystallographic texture, the main components of which are associated with the strain orientations through special off-orientations.

Diffusion coefficients and atomic mobilities in fcc Ni–Cu–Mo alloys: Experiment and modeling

Kinetic characteristics for Ni–Cu–Mo alloys are critically important for the establishment of the atomic mobility database in Ni-based superalloys. In the present work, the interdiffusion coefficients in fcc Ni–Cu–Mo alloys at 1273, 1373 and 1473 K have been determined from the concentration profiles across the solid–solid diffusion couples by means of EPMA (Electron Probe MicroAnalysis). The kinetic parameters for fcc Ni–Mo alloys are reassessed due to the discordance of self-diffusivity for Ni in fcc Ni–Mo and Ni–Cu phases. On the basis of the obtained interdiffusion coefficients in this work together with the thermodynamic description available in the literature, atomic mobilities of fcc Ni–Cu–Mo alloys were optimized as a function of the temperature and composition by means of CALTPP (CALculation of Thermo-Physical Properties) program. The three-dimensional surfaces for interdiffusivities, pre-exponential factor and activation energy for Cu and Mo were depicted for the purpose of understanding the variation of kinetic phenomenon. Good agreements between the calculated diffusivities, concentration profiles and diffusion paths and the experimental ones indicate that the presently obtained atomic mobilities of fcc Ni–Cu–Mo system are reliable.

Quantum-mechanical calculations of mixing enthalpy of the bcc phase of the Fe-Mo system for the ground state

The structural energies, formation enthalpies and bulk elastic moduli of bcc iron and molybdenum in the Fe – Mo system, are calculated for further use in the calculations of the bcc / bcc + Fe2Mo Laves phase boundary at low (room) temperatures.

Thermodynamic re-modelling of the ternary B–Fe–Mo system based on novel experimental data

In the present paper, the complete ternary B–Fe–Mo system is thermodynamically re-modelled based on our own experimental results and novel information reported in literature. A few key experiments were performed with ternary B–Fe–Mo alloys in order to clarify the morphology and stability of the MoxFe3-xB phase and measure temperatures of invariant second-order equilibria caused by the ferro-to-paramagnetic transformation of Fe-rich phases. In samples Mo6Fe64B30 and Mo10Fe65B25 (in at.%) annealed at 1403, 1363, 1343, 1023 and 873 K considerable amounts of MoxFe3-xB boride were detected to form at the expense of A1(Fe) or A2(Fe) and Fe2B phases. EBSD results show that the area fraction of this boride is higher when the annealing temperature is lower and the annealing time is longer. The sample Mo6Fe64B30 annealed at 1363 K for 15 h reached three-phase state Mo2FeB2+Fe2B+MoxFe3-xB. The sample Mo10Fe65B25 annealed at 1343 K for 5 h + 1403 K for 45 min + 1023 K for 5 h and quenched in a liquid Ga-In eutectic alloy was almost a three-phase A2(Fe)+Mo2FeB2+MoxFe3-xB material, with only about 2 area % Fe2B. The elaborated thermodynamic description was applied to calculate selected phase equilibria and thermodynamic properties in order to provide a comparison between the calculated and experimental results. The calculations are shown to reproduce available experimental phase equilibria data well. Enthalpies of formation at 0 K of the compounds Mo2FeB2 and MoFe1.93B3.73 were calculated to be equal to −216.0 and −277.4 kJ mol−1, respectively. The present value for Mo2FeB2 matches with first-principles calculations result of Wang at al. (−219.0 kJ mol−1).

Removal of metals from synthetic and real galvanic nickel-containing effluents by Saccharomyces cerevisiae

ABSTRACT The efficiency of Saccharomyces cerevisiae in the removal of heavy metals from effluents was tested using one real and four synthetics nickel-containing effluents. The removal of metal ions from synthetic effluents was studied as a function of pH, interaction time, nickel concentration and temperature. Characterisation of biosorption equilibrium was evaluated employing the Langmuir, Freundlich and Temkin models. The maximum sorption capacity of biomass for Ni(II) was 8.9 mg/g in Ni(II) system, 8.3 mg/g in Ni(II)–Cr(VI)–Fe(III), 11.9 mg/g in Ni(II)–Zn(II)–Sr(II)–Cu(II) and 7.3 in Ni(II)–Zn(II)–Cu(II)–Mo(VI) systems. The kinetics of the biosorption was described using pseudo-first order, pseudo-second order, Elovich model and the intra-particle Weber and Morris diffusion models. According to the thermodynamic parameters the biosorption can be described as a spontaneous process. Fourier-transform infrared analysis was carried out to identify the role of functional groups on metal ions binding. To determine the main metal species present in the solution at different pH values, thermodynamic calculations were performed. The effect of pH and sorbent dosage on metal removal from real industrial effluent was investigated. The two-stage sequential scheme of Ni(II) removal from effluent by the addition of different dosage of new biomass sorbent was proposed.

Structure and Physicomechanical Properties of Cast Titanium Alloys of the Ti−Nb−Mo System

Ternary alloys of the Ti–Nb–Mo system are obtained by the method of arc remelting with subsequent crystallization on a copper water-cooled hearth. In these alloys characterized by contents of alloying elements corresponding to the molybdenum equivalent (Moeqv) within the range 3.2–4.0, we observe the formation of hexagonal (α′) and orthorhombic (α′′ ) martensites. For higher Moeqv (4.6), we detect the appearance of a phase based on β -titanium instead of the orthorhombic martensite. In all analyzed alloys, we do not reveal the acicular microstructures characteristic of martensites. In these alloys, the (β -Ti) phase has higher hardness and Young’s modulus as compared with α′ and α′′. The Ti94Nb4Mo2 and Ti92.5Nb5Mo2.5 as-cast alloys are characterized by low Young’s moduli (∼ 70 GPa).

Nonstoichiometry in Inorganic Fluorides. III: Anionic Nonstoichiometry in MF2 (M = Ca, Sr, Ba)

Anionic nonstoichiometry in fluorides (replacement of F1– with O2–) deteriorates the quality of optical materials. Two reviews have been devoted to the initial stage of anionic nonstoichiometry: fluorides MF2 (M = Ca, Sr, Ba) are considered in this paper, and fluorides RF3 (R are 16 rare-earth elements) will be considered in the next one. These 19 fluorides play an important role in the fluoride materials science, comprising more than 70% of 27 MFm that are used to design two-component fluoride crystalline materials. The initial stage of anionic nonstoichiometry in MF2 is the only one in which oxofluorides MF2 – 2xOx with low oxygen content are formed. Partial replacement of F1– with O2– in the fluorite structure is accompanied by thermal stabilization of the structure type when moving up the temperature scale with a maximum in the melting curves of the oxofluoride phase, which decomposes upon cooling. No other intermediate phases containing fluorine and oxygen were found in the MF2–MO systems studied.