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Time-resolved X-ray photoelectron spectroscopy (TR-XPS) is used in a simulation study to monitor the excited state intramolecular proton transfer between oxygen and nitrogen atoms in 2-(iminomethyl)phenol. Real-time monitoring of the chemical bond breaking and forming processes is obtained through the time evolution of excitedstate chemical shifts. By employing individual atomic probes of the proton donor and acceptor atoms, we predict distinct signals with opposite chemical shifts of the donor and acceptor groups during proton transfer. Details of the ultrafast bond breaking and forming dynamics are revealed by extending the classical electron spectroscopy chemical analysis to real time. Through a comparison with simulated time-resolved photoelectron spectroscopy at the valence level, the distinct advantage of TR-XPS is demonstrated thanks to its atom specificity. [ABSTRACT FROM AUTHOR]

Heterotrimeric G proteins can be regulated by posttranslational modifications, including ubiquitylation. KCTD5, a pentameric substrate receptor protein consisting of an N-terminal BTB domain and a C-terminal domain, engages CUL3 to form the central scaffold of a cullin-RING E3 ligase complex (CRL3KCTD5) that ubiquitylates Gβγ and reduces Gβγ protein levels in cells. The cryo-EM structure of a 5:5:5 KCTD5/CUL3NTD/Gβ1γ2 assembly reveals a highly dynamic complex with rotations of over 60° between the KCTD5BTB/CUL3NTD and KCTD5CTD/Gβγ moieties of the structure. CRL3KCTD5 engages the E3 ligase ARIH1 to ubiquitylate Gβγ in an E3-E3 superassembly, and extension of the structure to include full-length CUL3 with RBX1 and an ARIH1~ubiquitin conjugate reveals that some conformational states position the ARIH1~ubiquitin thioester bond to within 10 Å of lysine-23 of Gβ and likely represent priming complexes. Most previously described CRL/substrate structures have consisted of monovalent complexes and have involved flexible peptide substrates. The structure of the KCTD5/CUL3NTD/Gβγ complex shows that the oligomerization of a substrate receptor can generate a polyvalent E3 ligase complex and that the internal dynamics of the substrate receptor can position a structured target for ubiquitylation in a CRL3 complex. [ABSTRACT FROM AUTHOR]

The substituent effects on cooperativity between pnicogen and halogen bonds in ternary complexes involving pyrimidine with substituents X in the 5-position (X = CN, NC, CF3, Br, Cl, F, H, CH3, C(CH3)3, NH2, N(CH3)2), H2FP, and ClF are investigated using theoretical calculations at the MP2/aug-cc-pVDZ level. The reduced density gradient (RDG) analysis indicates that the halogen and pnicogen interactions clearly stand out as attractive interactions. The calculated synergetic energies in ternary complexes are positive, which demonstrates the antagonist effect of pnicogen and halogen interactions upon each other. According to geometrical parameters, binding energies, molecular electrostatic potentials (MEPs), and the results of natural bond orbital (NBO), atoms in molecules (AIM), and nuclear magnetic resonance (NMR) analyses, pnicogen and halogen bonds are weakened in the ternary complexes where two pnicogen and halogen bonds coexist. The results indicate reduced electron density values, second-order perturbation energies, charge transfer values, and two-bonded spin–spin coupling constants for both pnicogen and halogen bonds in the ternary complex as compared to the isolated binary systems. Also, the results show that substituent effects on cooperativity between N...P pnicogen and N...Cl halogen bonds in considered system can be expressed by Hammett constants. [ABSTRACT FROM AUTHOR]

Herein, we report four new chiral 1,4,7‐triazacyclononane (TACN) derivatives and their corresponding nickel(II) chloride complexes. All TACN ligands are bearing one chiral N‐substituent and two alkyl (methyl or tert‐butyl) N‐substituents, and we have developed a new synthetic method for the dimethyl‐substituted TACN derivative, in order to prevent the rotational isomers that hinder the cyclization reaction. The nickel complexes change their coordination geometry significantly depending on the steric bulk of the N‐alkyl substituents, from a dinuclear tris(μ‐chloro)dinickel complex to mononuclear Ni‐dichloride and Ni‐chloride complexes. These complexes were then employed in the alkyl‐alkyl Kumada cross‐coupling reaction and revealed that the more sterically hindered ligands produced more homocoupled product rather than the cross‐coupled product, while the mononuclear Ni‐dichloride complex exhibited significantly lower catalytic activity. These chiral complexes were also employed in enantioconvergent cross‐coupling reactions as well, to afford significant enantioenrichment. Overall, the least sterically hindered Ni complex yields the best yields in the alkyl‐alkyl Kumada cross‐coupling reaction among the four complexes investigated, as well as the highest enantioselectivity. [ABSTRACT FROM AUTHOR]

The diffusion processes during the contact melting at the boundary of explosively welded VT1-0 titanium with CuNi19 (melchior) and CuNi45 (constantan) alloy composites were studied. Heat treatment of composites led to the formation of the interaction zone at the joint boundary. The interaction zone in VT1-0 + CuNi19 consists of TiCuNi and αTi + Ti2Cu(Ni) continuous layers as well as a mixture of TiNi(Cu) + TiCu(Ni) + Ti2Cu(Ni) intermetallics. It has been shown that an increase in the nickel content in the case of VT1-0 + CuNi45 composite leads to a decrease in the temperature of contact melting, a change in its mechanism, an increase in the titanium content in the interaction zone, and the appearance of additional Ti2Ni(Cu) intermetallic in its composition. [ABSTRACT FROM AUTHOR]

The potential applications of nanowires in thermal management and thermoelectric energy conversion have sparked extensive research on thermal transport in various nanowires. Nickel nanowires, with their unique properties and promising applications, have been extensively studied. However, the influence of size, particularly the impact of kink structures, on the thermal transport behavior in nickel nanowires remains unclear. In this paper, we employed electron-beam lithography and liftoff techniques to fabricate suspended nickel nanowires with varying sizes and kinks to experimentally investigate the size and kink effect on the thermal conductivity. The experimental results revealed that the thermal transport behavior of nickel nanowires is significantly influenced by both size and kink effects. Notably, as the nanowire size decreases, the thermal conductivity also decreases. Furthermore, we discovered that the thermal conductivity can be adjusted by altering the number and angle of kinks. Increasing the number of kinks from 18 to 36 resulted in a significant decrease in thermal conductivity. In contrast, as the kink angle decreased from 157° to 90°, the thermal conductivity also decreased. However, intriguingly, when the kink angle was further decreased from 90° to 43°, the thermal conductivity increases. This non-monotonic change in thermal conductivity with the kink angle provides an interesting insight into the intricate behavior of heat carriers in kinked nickel nanowires. Additionally, we found that varying the alloy elements can profoundly alter the thermal conductivity of nanowires with kinks. These results offer valuable insights into the behaviors of heat carriers, including electrons and phonons, during heat transfer in nickel nanowires. [ABSTRACT FROM AUTHOR]

The facile synthesis of large size borophene is highly desirable, especially in reserving green energy by borophene-based Li-ion batteries (LIBs). In this study, an easy method of synthesizing a series of nickel foam (NF) deposited with borophene sheets without the use of catalysts is reported via an improved chemical vapor deposition (CVD) process. During the CVD process, the B2O2 vapor was moved to the heated nickel foam and converted into Ni3B and crystalline B under an H2 atmosphere. Numerous micron-sized lamellar borophene with thicknesses of less than 2 nm were deposited on the surface of the nickel foam, and the borophene sheets displayed ultrathin and transparency. Deep microstructural analysis revealed the crystalline nature of pure B in the as-obtained borophene sheets, and the β12-phase is dominant. The β12-borophene holds great potential for designing high-capacity anode material for LIBs. When the nickel foam-supported borophene sheets were directly used as a self-supporting binder-free anode material for LIBs, the NF framework not only hindered the aggregation of borophene sheets and alleviated the strain change during the lithiation/delithiation process but also provided a three-dimensional highway conductive network for fast electron transport. The fabricated electrodes exhibit superior lithium storage capacity and cyclic stability than blank NF electrodes. However, the results suggest that this is still far lower than the theoretical lithium storage capacity of the boron anode. The kinetics analysis combined with density functional theory calculations demonstrated that slow electron and ion transportation in the electrodes is attributed to the existence of the Ni3B phase and deactivated borophene. This study may provide vital guidance for designing high-performance borophene-based LIBs. [ABSTRACT FROM AUTHOR]

We study integer-valued matrices with bounded determinants. Such matrices appear in the theory of integer programs (IPs) with bounded determinants. For example, an IP can be solved in strongly polynomial time if the constraint matrix is bimodular: that is, the determinants are bounded in absolute value by two. Determinants are also used to bound the ℓ 1 distance between IP solutions and solutions of its linear relaxation. One of the first to quantify the complexity of IPs with bounded determinants was Heller, who identified the maximum number of differing columns in a totally unimodular matrix. Each extension of Heller's bound to general determinants has been superpolynomial in the determinants or the number of equations. We provide the first column bound that is polynomial in both values. For integer programs with box constraints, our result gives the first ℓ 1 distance bound that is polynomial in the determinants and the number of equations. Our result can also be used to derive a bound on the height of Graver basis elements that is polynomial in the determinants and the number of equations. Furthermore, we show a tight bound on the number of differing columns in a bimodular matrix; this is the first tight bound since Heller. Our analysis reveals combinatorial properties of bimodular IPs that may be of independent interest. Funding: J. Lee was supported in part by the Office of Naval Research [Grant N00014-21-1-2135] and the Air Force Office of Scientific Research [Grant FA9550-19-1-0175]. J. Paat was supported by a Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant [Grant RGPIN-2021-02475]. [ABSTRACT FROM AUTHOR]

• We describe a model of optimal consumer-merchant exchange of cash payments. • Diary data are used to quantify the burden of exchanging currency notes and coins. • The model and data are used to analyze the effects of eliminating the one-penny coin. • Penny elimination would reduce the burden of exchanging cash. • Penny elimination would result in little or no inflationary consequences. • Elimination of the penny and the nickel would not reduce this burden relative to penny elimination only. This article quantifies the burden of exchanging currency notes and coins using a model of optimal consumer-merchant exchange of cash payments and consumer payment choice diary data. The model is then applied to analyze a policy debate whether to eliminate the penny coin from circulation. We find that penny elimination would reduce the burden of exchanging cash and will not have any significant inflationary consequences caused by price rounding. Surprisingly, a removal of both the penny and nickel coins from circulation would slightly increase (not decrease) the burden relative to penny elimination only. [ABSTRACT FROM AUTHOR]

This paper explores the variation pattern of nickel futures prices using the daily closing levels of the nickel futures price index of the London Futures Exchange and the Shanghai Futures Exchange. The data coarse-graining method is employed to transform the continuous time series data of price index changes into symbols {P, N, M}, which are slid through continuous windows to form the modalities of price index linkage fluctuations. By treating the modalities as nodes and the transformations between them as edges, a weighted directed complex network is constructed to represent the linked volatility of the LME and SHFE nickel futures indices time series. The complex network is applied to analyse the network characteristics and obtain the inner pattern of the linked fluctuations. The results show that the complex network of time series linked volatility of the LME and SHFE nickel futures indices exhibits a power-law nature, with closely linked subgroups formed within it. And the mode transitions within these subgroups follow certain patterns. This paper also identifies core positioned modes and important intermediate modes that reflect the dynamics of nickel prices in reality. The method presented in this paper may be extended to related fields and has good applicability. [ABSTRACT FROM AUTHOR]

Olivine, one of the most abundant silicates on earth, thermodynamically captures CO2 in relevant amounts during its dissolution. Upscaling the use of this mineral as a replacement for sand or gravel may contribute to reduce concentrations of greenhouse gasses in the atmosphere. However, the reliable quantification of weathering rates and prognoses for effects of various environmental conditions on weathering are lacking. This currently inhibits the monitoring, reporting and verification of CO2 capture and hampers the exploitation of the carbon dioxide removal economy. A mineral dissolution model was developed, and olivine weathering rates were directly coupled to particle sizes of the ground mineral. A particle size-dependent calculation approach, based on the shrinking core model, showed faster weathering rates as compared to a single-size, monodisperse approach. This provided a better underpinning of the prediction of the overall weathering and, consequently, the sequestration rate of CO2. Weathering of olivine releases nickel, which is incorporated in the mineral. The dissolution model was coupled to advanced biotic ligand models (BLM) for nickel in order to assess potential chronic ecotoxicological risks upon release in the environment. Predicted no-effect concentrations for nickel showed that both the release of Mg and the increase of pH following olivine weathering significantly lowers nickel ecotoxicity. [ABSTRACT FROM AUTHOR]

Microbial electrolysis cell can utilize biocathode attached to methanogens to reduce CO2 to methane.A conductive nickel-based polyvinylidene fluoride（Ni-PVDF） composite hollow fiber membrane was prepared by electroless nickel plating.The Ni-PVDF hollow fiber membrane was assembled into a membrane module electrode, which served as the biocathode of the microbial electrolysis cell for methane production.The H2 produced by the hydrogen evolution reaction catalyzed by the cathode nickel layer and CO2 were utilized by the hydrogenotrophic methanogens to produce methane through indirect electron transfer.The results showed that the cumulative methane production（2 176.24 mmol/（L·m²)) of the direct CO2 transport system using the Ni-PVDF hollow fiber membrane module cathode was much greater than that of the indirect CO2 transport system with the membrane module only acting as the cathode（613.94 mmol/（L·m²)) after the system run stably.The high specific surface area of the membrane module cathode and the direct CO2 transmission of the cathode greatly reduce the gas-liquid mass transfer resistance, thus ensuring the high methane production of the direct CO2 transmission system. [ABSTRACT FROM AUTHOR]

The formation of carbon–carbon bonds from prebiotic precursors such as carbon dioxide represents the foundation of all primordial life processes. In extant organisms, this reaction is carried out by the carbon monoxide dehydrogenase (CODH)/acetyl coenzyme A synthase (ACS) enzyme, which performs the cornerstone reaction in the ancient Wood–Ljungdahl metabolic pathway to synthesize the key biological metabolite, acetylCoA. Despite its significance, a fundamental understanding of this transformation is lacking, hampering efforts to harness analogous chemistry. To address these knowledge gaps, we have designed an artificial metalloenzyme within the azurin protein scaffold as a structural, functional, and mechanistic model of ACS. We demonstrate the intermediacy of the NiI species and requirement for ordered substrate binding in the bioorganometallic carbon–carbon bond-forming reaction from the one-carbon ACS substrates. The electronic and geometric structures of the nickel-acetyl intermediate have been characterized using time-resolved optical, electron paramagnetic resonance, and X-ray absorption spectroscopy in conjunction with quantum chemical calculations. Moreover, we demonstrate that the nickel-acetyl species is chemically competent for selective acyl transfer upon thiol addition to biosynthesize an activated thioester. Drawing an analogy to the native enzyme, a mechanism for thioester generation by this ACS model has been proposed. The fundamental insight into the enzymatic process provided by this rudimentary ACS model has implications for the evolution of primitive ACS-like proteins. Ultimately, these findings offer strategies for development of highly active catalysts for sustainable generation of liquid fuels from one-carbon substrates, with potential for broad applications across diverse fields ranging from energy storage to environmental remediation. [ABSTRACT FROM AUTHOR]

The association between two intrinsically disordered proteins (IDPs) may produce a fuzzy complex characterized by a high binding affinity, similar to that found in the ultrastable complexes formed between two well-structured proteins. Here, using coarsegrained simulations, we quantified the biophysical forces driving the formation of such fuzzy complexes. We found that the high-affinity complex formed between the highly and oppositely charged H1 and ProTα proteins is sensitive to electrostatic interactions. We investigated 52 variants of the complex by swapping charges between the two oppositely charged proteins to produce sequences whose negatively or positively charged residue content was more homogeneous or heterogenous (i.e., polyelectrolytic or polyampholytic, having higher or lower absolute net charges, respectively) than the wild type. We also changed the distributions of oppositely charged residues within each participating sequence to produce variants in which the charges were segregated or well mixed. Both types of changes significantly affect binding affinity in fuzzy complexes, which is governed by both enthalpy and entropy. The formation of H1-ProTa is supported by an increase in configurational entropy and by entropy due to counterion release. The latter can be twice as large as the former, illustrating the dominance of counterion entropy in modulating the binding thermodynamics. Complexes formed between proteins with greater absolute net charges are more stable, both enthalpically and entropically, indicating that enthalpy and entropy have a mutually reinforcing effect. The sensitivity of the thermodynamics of the complex to net charge and the charge pattern within each of the binding constituents may provide a means to achieve binding specificity between IDPs. [ABSTRACT FROM AUTHOR]

• β-NiAl phase precipitates in a novel high Ru-containing Ni-SC. • Ru element is found to be obviously biased in β-NiAl phase. • The partition of Ru assists nucleation of β-NiAl phase during solidification. • Studies based on the solidification path of experimental alloy were carried out. The precipitation of β-NiAl phase in a high Ru-containing Ni-based single crystal superalloys was investigated. The β-NiAl phase is mainly distributed in the interdendritic region of the as-cast structure. And it was found parts of Ru elements were polarized in β-NiAl phase as the existence of strong bonds between Ru atoms and Al atoms. In addition, the solidification path of the experimental alloy passes through the region of the L → L 1 + γ → L 2 + γ + β-NiAl → L 3 + γ + β-NiAl + precipitated γ′ → γ + β-NiAl + precipitated γ′ + γ/γ′ eutectics. It provides experimental data and theoretical guidance for the composition design of the novel Ru-containing high-generation Ni-SCs. [ABSTRACT FROM AUTHOR]

• The added interlayer can decrease the width of the diffusion zone near the interface. • The formation tendency of Laves phase can be decrease by added interlayer. • The added interlayer can promote the formation of Ni 2 (Cr,Mo). • The strength of the plate adding nickel interlayer increased by 35 % to 341 MPa. The brittle Laves phase forming on the interfaces of nickel-based composite plate has evident effect on its application. For the purpose of decreasing the formation of brittle phase and improving mechanical performance, X65/IN625 composite plates were synthesized using vacuum hot pressing under varying conditions. The investigation was focused on understanding the bonding properties and interfacial microstructure of these composites. The results show that the optimal process is 30 min holding time, 30 MPa pressure and 1050 °C heating temperature. It is worth noting that after the addition of nickel and invar alloy interlayers to the composite plate, the interface bonding strength of the composite plate is significantly improved by approximately 35 % (341 MPa) and 17 % (305 MPa), respectively, compared to plates without interlayer. This is because the addition of nickel and invar alloy layer can decrease the width of the diffusion zone near the interface and effectively inhibit the diffusion of Fe element, thereby reducing the formation tendency of Laves phase, and promoting the formation of Ni 2 (Cr,Mo). [ABSTRACT FROM AUTHOR]

Nickel ferrite (NiFe 2 O 4) nanostructures (NSs) were synthesized via a low-cost and reproducible co-precipitation method. The as-synthesized material was annealed at different temperatures to investigate electrochemical performances for oxygen reduction reaction (ORR) and energy storage capacity. The X-ray diffraction (XRD) pattern confirmed the cubic structure of NiFe 2 O 4 (NF) NSs. The decreased agglomeration and increased particle size were observed by field effect scanning electron microscopy (FE-SEM) with annealing temperature. The presence of Ni–O and Fe–O bonds at tetrahedral and octahedral sites was confirmed by Fourier transform infrared (FTIR) spectroscopy. The electrochemical analysis studied using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) demonstrated that the NF NSs annealed at 900 °C exhibited impressive electrochemical activity with a specific capacitance of ∼136 F/g, outperforming samples synthesized at lower temperatures. Moreover, the electrode material displayed excellent long-term stability over 3000 cycles for ORR activity. The remarkable electrochemical performance of NF NSs at higher annealing temperatures highlights their potential for future energy storage and conversion devices. [Display omitted] • The NiFe 2 O 4 NPs were successfully synthesized by using a simple and economical co-precipitation method. • The cubic nature of the NF NPs was confirmed by XRD and HR-TEM analysis. • The NF annealed at 900 °C showing the highest capacitance of 136 F/g. • The NF NPs having excellent long-term stability over 3000 cycles. [ABSTRACT FROM AUTHOR]

Metal mobilization event was linked to shear-associated granodiorite magmatism. [Display omitted] • Um Samiuki volcanogenic massive sulfide deposit in Egypt's South Eastern Desert. • Zircon U-Pb and sulfide Re-Os dating reveal the genetic link with the host rocks. • Ore-hosted stratum formed ∼700 Ma, and a crosscutting granodiorite at 624 Ma. • Sulfide minerals show high Re-Os ratios and crustal isotope signature. • Ductile shearing formed discrete sulfide masses, followed by intermittent brittle deformation. • Ag-mineral inclusions in galena and solid solution in sulfides contribute to Ag budget. The Um Samiuki deposit in the South Eastern Desert of Egypt is a Kuroko-type volcanogenic massive sulfide deposit associated with arc-related bimodal volcanic rocks. SIMS U-Pb zircon ages of the host metavolcanic rocks and a crosscutting granodiorite intrusion are integrated with Re-Os isotopes of ore sulfides, allowing the determination of the genetic relationships between sulfide mineralization and host rocks to be determined. Zircon U-Pb dating reveals that the ore-hosted stratum of banded tuffs formed at ∼700.0 ± 7.3 Ma, whereas the granodiorite yielded a concordia age of 624.0±8.5 Ma. Sulfide mineral separates (pyrite, sphalerite, chalcopyrite) and sulfide mixtures from the massive ores have significantly high radiogenic Re-Os concentrations and ratios. Regression of seven 187Re/188Os-187Os/188Os data points with the corresponding uncertainty correlation values yields a 624±46 Ma age (2σ, MSWD = 0.56), with an initial 187Os/188Os ratio of 3.58±0.7, thereby pinpointing a distinctive crustal isotope signature. Evolution towards textural equilibrium by recrystallization, as revealed by grain growth and annealing textures in the ores, suggests that ductile shearing and penetrative deformation of the host metavolcanic/metavolcaniclastic rocks led to the formation of discrete sulfide disseminations and masses. Deformed, rolled and rotated pyrites in veins and tension gashes with or without quartz evidently suggests an intermittently rejuvenated brittle deformation regime superimposed on the early ductile deformation textures. Pyrite, galena, chalcopyrite, and sphalerite contain elevated Ag contents between 5 and 812 ppm. Two pyrite generations can be distinguished with the earlier one (Py1) having the highest Ag contents of all sulfides. Silver was released during replacement of Py1 by a late assemblage (Py2-galena-chalcopyrite-sphalerite) with some Ag incorporated into the late sulfides but most Ag was released and retained in discrete Ag minerals like cerveilleite, hessite and acanthite. Time-resolved analyses of LA-ICP-MS data reveal the presence of micron-scale Ag-bearing inclusions in galena while other base metal sulfides also contribute a notable part to the Ag budget of Um Samiuki ore. The new geochronological data integrated with results of the microscopic and microanalytical analyses of the sulfide phases provide an updated insight into a metal mobilization event in the Um Samiuki volcanogenic massive sulfides, roughly coincided with shear-associated granodiorite magmatism. [ABSTRACT FROM AUTHOR]

Along time, many minted coins were withdrawn from circulation, being replaced with new ones. The returned obsolete metal coins were melted in order to use the alloy for other purpose. Between the withdrawing and melting, some of the metal coins were cancelled by destruction of the original shape and dimension, using some adequate tools. The paper presents some aspects about the cancelling method used on the Romanian old nickel coins. In the first part of the paper, the introductive aspects about the used cancelling methods are presented; also, there are presented some examples. In the paper second part, the simplified 3D model computed for the cancelling dies, respectively the coin, are presented. Then, there are introduced the assembled models, corresponding to each cancelling case, which consist by the obverse and reverse cancelling dies, having the coin inside them. For the each model, the finite element analysis is realized and is achieved for different initial conditions. The final part of the paper presents the analysis results and also the conclusions. [ABSTRACT FROM AUTHOR]

A multi-physics model has been developed to investigate the molybdenum and nickel distribution in large-scale Ti-0.3 wt.% Mo-0.8 wt.% Ni slab ingots obtained by electron beam cold hearth melting. Numerical methods are pivotal in revealing the distribution trends of molybdenum and nickel in slab ingot in different casting conditions. The distribution of molybdenum slightly changed between 0.28 and 0.32 wt.% in the solidified ingot. However, the sharp change in the nickel distribution (between 0.73 and 1.53 wt.%) was caused by the fluid velocity decrease along the flow direction, resulting from a weakened vortexing effect. Additionally, the increase of the casting speed or pouring temperature led to a deeper molten pool and evident vortexing effect. A potential relationship indicates the decrease of nickel segregation degree at higher pouring temperatures, or the casting speed decrease within the research scope. [ABSTRACT FROM AUTHOR]

The paper is devoted to the experimental and theoretical studies of self-sustained oscillations and wave phenomena during CO oxidation on Ni foil. A new type of spatial structures arising due to the redox processes of the catalyst and observed under isothermal conditions at atmospheric pressure were studied. A 3D distributed mathematical model was constructed, which describes the color change and the propagation of kinetic waves of nickel oxidation–reduction in a flow-through reactor. The main reason for the wave phenomena and their propagation during CO oxidation on nickel was shown to be the presence of an oxygen concentration gradient in the flow-through reactor due to the effect of mass transfer on the reaction rate. [ABSTRACT FROM AUTHOR]

A rotating disk method is used to investigate the dissolution rate of metallic iron, nickel, and their alloys in nitric acid media. Discs 2 cm in diameter made of nickel grade N1 and Armco iron, as well as two samples with an Ni:Fe ratio of 15:85 and 50:50 are used. The effect of temperature, initial nitric acid concentration, disk rotation rate, and process duration on specimen dissolution rate are investigated. The rate is determined by the amount of dissolved metal per unit of time from a disk unit surface. Regression analysis is used to describe the effect of nitric acid concentration on specimen dissolution rate. It is found that the dissolution rate of iron metal is up to 20–60 times faster than nickel metal dissolution rate. The effect of HNO3 temperature and initial concentration when dissolving Ni and Fe alloys in nitric acid is investigated. With an increase in temperature from 303 to 353 K ([HNO3] = 0.2 M, Ni:Fe = 50:50) the amount of dissolved Fe and Ni increases by a factor of 8–9. Dissolution of Ni:Fe alloy (15:85) under the same conditions results in an increase in dissolved iron by a factor of four. An increase in nickel concentration in solution occurs within 30 minutes, after which the concentration does not change. In experiments with Ni:Fe alloy = 50:50 the amount of dissolved Fe is 1.8–2.3 times greater than the amount of dissolved Ni depending on the initial acidity. [ABSTRACT FROM AUTHOR]

[Display omitted] • The surface phosphorus-induced strategy generates Ni-P(δ−) and Fe-P(δ−) stable bonding states. • The recombination of photoinduced electron-hole pairs was inhibited. • Enhanced absorbance intensity and absorption range. • Hydrogen evolution performance is 82 times of the NiFe-LDH. Light-driven semiconductor splitting of water for hydrogen production is becoming increasingly important in the direction of obtaining clean energy. In this study, high-temperature P-induced corrosion of NiFe-LDH was used to generate P-metal strong surface bonding states. The surface layout of Ni/Fe-P(δ−) covalent bonds on the one hand enriches the active sites for photocatalytic hydrogen evolution and opens up the valve for accelerated hydrogen production. On the other hand, it opens the migration channel for photogenerated electrons, which broadens the electron supply for photocatalytic hydrogen generation. FTIR spectroscopy and XPS results showed that Ni/Fe-P covalent bonds were successfully deployed on the catalysts. PL results showed that the introduction of covalent bonds had a facilitating effect on promoting the separation and migration of photogenerated electrons. The design of Ni-P(δ−) and Fe-P(δ−) bonds was further confirmed by In situ irradiated X-ray Photoelectron Spectroscopy to open the channels for trapping and transporting electrons. Based on the experimental results, we propose a possible bimolecular mechanism for synergistic hydrogen evolution, which provides novel and unique insights into the in-depth analysis of the influence of surface bonding states on the photocatalytic mechanism. [ABSTRACT FROM AUTHOR]

[Display omitted] • C(sp3) to C(sp2) relaxation depends on ion dose and annealing temperature. • Nitrogen exists mainly in C–N/C N bonding configuration below critical dose. • Ion retention probability decreases for higher doses due to recombination-assisted desorption. • Nitrogen desorption onset increases with ion dose. The properties of ultra-shallow nitrogen layers (<1 nm thick) in diamonds produced by very low energy (200 eV) N 2 + implantation in polycrystalline diamond films at different doses (1.25×1014, 3.50×1014, 7.85×1014, 1.30×1015 and 9×1015 ions·cm−2), followed by thermal annealing, are investigated by in situ X-ray photoelectron spectroscopy. Spectral analyses of C(1s) and N(1s) peaks reveal that a chemical effect occurs depending on nitrogen local concentration and annealing temperature. Nitrogen exists in a predominant C N/C–N bonding configuration, followed by minor contributions of C≡N and quaternary-N configurations. Annealing (300–1000 °C) imparts complex effects that depend on local nitrogen concentration and bonding. The onset of nitrogen thermal desorption increases with ion dose: 300 °C for 1.25×1014 and 3.50×1014, 400 °C for 7.85×1014, and ∼650 °C for 1.30×1015 and 9×1015 ions·cm−2. Upon annealing to 1000 °C, the remaining nitrogen concentration in the diamond subsurface region increases with ion dose. The C N/C–N configuration was more thermally stable than the C≡N, while the quaternary-N is constant with annealing temperature. The nitrogen ion retention probability increased for 1.25×1014 and 3.50×1014 and decreased for the higher doses due to recombination-assisted desorption. This study may have important implications for stabilizing near-surface NV- centers for quantum sensing applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new Schiff-base compound was synthesized and characterized by elemental analysis, Fourier transform infrared (FT-IR), UV–vis, mass spectroscopy, and NMR. • The Schiff-base complexation capability with different cations was examined and there were not any significant changes in the nature of absorption spectra except in the case of Ni2 + solution. • The Schiff-base demonstrated a consistence absorption intensity change related to Nickel (II) concentration at wavelength 385 nm in range of 0–50 µM, so that the Schiff-base was exploited as Nickel (II) optical chemical-sensor. • Biological activity for the Schiff-base shows a high antimicrobial property so that it could be used for the treatment of some common diseases caused by Staphylococcus aureus especially MRSA. A receptor in the form of (E)-(4-(thiophen-2-yl)phenyl)-N-(4H-1,2,4-triazol-4-yl)methanimine Schiff base L was synthesized through the reaction of 4-amino-4H-1,2,4-triazol with 4-(2-thiazol)benzaldehyde. The resulting Schiff base L was characterized by physicochemical techniques such as elemental analysis, UV-vis, Fourier transform infrared (FT-IR), mass spectrometry, and NMR. The Schiff base L receptor was exploited as an optical chemical sensor for nickel (II) metallic cationic concentration determination. The chemosensor demonstrated a consistent absorption intensity change at 385 nm related to the nickel (II) concentration in the range of 0–50 µM with a calibration sensitivity of 0.0052 Abs/µM in addition to calibration linearity (R2 = 0.9839) and possessing a response time of less than 5 mins. Other cations, Fe2 + Cu2+, Co2+, Zn2+, Cd2+, Mn2+, Mg2+, Cr2 + Ag+, Ca2+, Al3+, Li+, Na+, K+, Nd3+, Dy3+, Sm3 + and Tb3+, did not show any considerable change in absorbance intensity, except in the case of Pb2 + and Gd3+, where interference was observed. The mole-ratio method was used to determine the formula for the resulting Ni2 + -ligand complexation, and the Ni2+:ligand mole ratio was 1:1. In vitro antimicrobial activity of the Schiff base L exhibited a bactericidal effect against staphylococcal strains regardless of their different virulence characteristics. [ABSTRACT FROM AUTHOR]

Regulating electronic structure can fundamentally and effectively change the electrocatalytic HER performance of nickel selenide. Herein, we designed a highly-active electrocatalyst of interface-rich 1 T-MoSe 2 /NiSe via the interface-induced phase transition method from NiSe 2 to NiSe. As expected, 1 T-MoSe 2 /NiSe showed superior HER performance in alkaline and alkaline seawater solution, which only required 98 and 104 mV at 10 mA·cm−2. Experimental and theoretical data displayed that the formation of heterointerface and phase transition in 1 T-MoSe 2 /NiSe could effectively regulate the phase structure and hydrogen adsorption energy in nickel selenide, thus improving the catalytic performance. Meanwhile, an abundance of specific surface area in 1 T-MoSe 2 /NiSe could allow reactants to easily arrive the active site and produce high electrocatalytic performance. In all, this work can offer a new vision for the designing highly-efficient nickel selenide-based electrocatalysts via the interface-induced phase engineering strategy. [Display omitted] • An of interface-rich 1 T-MoSe 2 /NiSe has been successfully prepared. • 1 T-MoSe 2 /NiSe shows excellent HER activity in water/seawater splitting. • The mechanism of the greatly improvement has been explored. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the potential of the woody nickel hyperaccumulator species Blepharidium guatemalense (Standl.) Standl. for agromining in southeastern Mexico. Pot trials consisting of nickel dosing (0, 20, 50, 100, and 250 mg Ni kg−1), and synthetic and organic fertilization were conducted. Field trials were also undertaken with different harvesting regimes of B. guatemalense. Foliar nickel concentrations increased significantly with rising nickel additions, with a 300-fold increase at 250 mg Ni kg−1 treatment relative to the control. Synthetic fertilization strongly increased nickel uptake without any change in plant growth or biomass, whereas organic fertilization enhanced plant shoot biomass with a negligible effect on foliar nickel concentrations. A 5-year-old stand which was subsequently harvested twice per year produced the maximum nickel yield tree−1 yr−1, with an estimated total nickel yield of 142 kg ha−1 yr−1. Blepharidium guatemalense is a prime candidate for nickel agromining on account of its high foliar Ni concentrations, high bioconcentration (180) and translocation factors (3.3), fast growth rate and high shoot biomass production. Future studies are needed to test the outcomes of the pot trials in the field. Extensive geochemical studies are needed to identify potential viable agromining locations. Novelty Statement Our research team is a pioneer in the discovery of metal hyperaccumulator plants in Mesoamerica with at least 13 species discovered in the last 2 years. This study is the first to assess the potential of nickel agromining (phytomining) in Mexico (and in all the American continent), using one of the strongest nickel hyperaccumulators reported so far. The promising results of this study are the basis for optimal agricultural management of Blepharidium guatemalense. [ABSTRACT FROM AUTHOR]

Surface modifiers through redox routes emerged as the most preferred in forensic science. Aryldiazonium salts stabilized with tetrachloroaurate (III) are excellent redox modifiers in the development of latent fingerprints on nickel surfaces. Nickel coins were fingerprinted and developed with a stable diazonium salt [O2N‐4‐C6H4N≡N]AuCl4. The developed surfaces were studied using XPS that showed the presence of the characteristic gold and organic modifier peaks. Also, imaging analysis using SEM showed clusters of gold. EDS quantitative analysis estimated a good amount of gold presence on the fingerprinted compared with the non‐fingerprinted area. Our results are important in the analysis of nickel coins using a spontaneous route by simply depositing diazonium salt solution drops on the nickel surface without any additional reducing agent. This work brings strong supporting evidence for the efficient combination of diazonium surface chemistry and high‐performance surface analytical tools (XPS, SEM‐EDS) in the fast, spontaneous development of fingerprints and their morphological and chemical composition assessments. [ABSTRACT FROM AUTHOR]

Copper, diagnostics, dimethylglyoxime, metal release, nickel, nickel allergy, DMG Keywords: copper; diagnostics; dimethylglyoxime; DMG; metal release; nickel; nickel allergy EN copper diagnostics dimethylglyoxime DMG metal release nickel nickel allergy 431 433 3 04/14/22 20220501 NES 220501 The dimethylglyoxime (DMG) spot test is widely used to screen for nickel release that may cause allergic nickel contact dermatitis in allergic individuals. The tested earring with nickel release of 0.87 g/cm SB 2 sb /week was expected to become DMG spot test positive, but this result was possibly masked due to the brown discolouration caused by a DMG-copper reaction (Figure 2). [Extracted from the article]

Hydrogen used as an energy carrier can be obtained by water electrolysis. To improve the energy efficiency of this process porous nickel catalysts are often used. The paper investigates the electrodeposition regularities and the porous nickel deposits morphology and the properties of nickel foams toward the hydrogen evolution reaction. During electrodeposition at high current density, nickel deposits with macro- and micropores are formed. The dependence between the fraction of macropores on the deposit surface and the electrolysis time is described by the empirical equation. Total porosity of loose nickel deposits is much higher than the porosity of foams. However, the surface macropores fraction of deposits studied is approximately the same, while the microporosity of loose deposits is significantly higher. The values of nickel deposits total porosity calculated by the model agree with the values obtained by experimental data. The highest density of macropores on the surface is observed for the foam thickness of 100 μm. These data correlate with the results of polarization measurements. When the foam thickness increases up to 100 μm, hydrogen evolution overvoltage in the alkali solution decreases and the efficiency of nickel foam as a cathode material increases. [Display omitted] • A change in the nickel deposits porosity during electrodeposition was determined. • Empirical equation for calculating the macropores fraction is proposed. • A change in deposits microporosity was calculated using model representations. [ABSTRACT FROM AUTHOR]

Systematic measurements of the magnetic moment of hexagonal 6H-BaTiO3 + 0.04 BaO + x NiO (0.005 ≤ x ≤ 0.02) ceramics were performed to study the influence of Ni ions on the magnetic properties. By temperature-dependent measurements of the paramagnetic susceptibility at 90 kOe, the Ni2+ ion was identified as the majority defect in air-sintered Ni-doped hexagonal barium titanate. Q-band EPR investigations of a 2.0 mol% Ni-doped single crystal revealed three different Ni centers located at Ti sites: first, Ni3+ ions at Ti sites in intact oxygen octahedra, second, Ni3+ associated with an oxygen vacancy and third, the presence of Ni2+ centers leading to a forbidden transition. The Ni3+—VO associate characterized by a vacancy in the face-sharing oxygen plane of the oxygen octahedra can be ruled out. The crystal field parameters of the Ni2+ defect were estimated by a combined fitting of the paramagnetic susceptibility and the EPR fine structure parameter D to B 0 4 ≈ −17,300 cm−1, B 0 2 ≈ 2500 cm−1 and B 3 4 ≈ 19,000 cm−1. [ABSTRACT FROM AUTHOR]

A method for phase and electronic modulation of highly dispersed WC X nanoparticles through Ni coupling has been developed, which shows enhanced electrocatalytic OER performance. Exploring efficient, stable, and earth-abundant electrocatalysts for oxygen evolution reaction (OER) is of great significance for clean and renewable energy conversion technologies. In this work, in situ uniform Ni-doped tungsten carbide (Ni/WC X) nanoparticles (~3 nm) on carbon nanofibers (Ni/WC X -CNFs) that were to function as efficient OER catalysts were developed. Both the composition and electronic state of tungsten carbide (WC X : W-WC-W 2 C) could be regulated through varied Ni coupling. Owing to the synergistic effect between Ni and WC X , the reaction kinetics were facilitated, resulting in improved OER activity with low overpotentials of η 10 = 350 mV (modified glassy carbon electrode) and η 10 = 335 mV (self-supporting electrode). This work opens a facile territory for the development of cost-effective and highly promising OER electrocatalysts for use in real life applications. [ABSTRACT FROM AUTHOR]

The Li 1.02 Ni 0.05 Mn 1.93 O 4 cathode material exhibits a better rate capability than that of the LiNi 0.05 Mn 1.95 O 4. Moreover, the Li 1.02 Ni 0.05 Mn 1.93 O 4 shows the well-developed crystal structure with the (1 1 1), (1 1 0) and (1 0 0) crystal planes. The (1 1 1) crystal planes possess the minimum Mn dissolution and the (1 1 0) and (1 0 0) crystal planes are well consistent with the Li+ diffusion channel. Various Li-rich spinel Li 1+ x Ni 0.05 Mn 1.95- x O 4 (0 ≤ x ≤ 0.10) cathode materials with a truncated octahedron were synthesized by a solution combustion method. The relationship of crystalline structure, particles morphology and electrochemical properties of the as-prepared samples was investigated via a series of physicochemical characterizations. The Li-Ni co-doping changes the lattice parameters and atomic configuration, whilst resulting in a contraction of unit cell dimension and giving rise to a variation of bond length. In this regard, the shrinkage of octahedral MnO 6 provides a robust structure and the expansion of tetrahedral LiO 4 facilitates a fast electrochemical process. Additionally, the resulted polyhedral Li 1+ x Ni 0.05 Mn 1.95- x O 4 samples present the exposed (1 1 0), (1 0 0), and (1 1 1) crystal planes, which provide the favorable Li+ ions diffusion/transmission channel and alleviate Mn dissolution. Owing to these merits of polyhedral structure and Li-Ni co-doping, the optimized Li 1.02 Ni 0.05 Mn 1.93 O 4 exhibits good electrochemical performance with high initial discharge capacity of 119.8, 107.1 and 97.9 mAh·g−1 at 1, 5 and 10 C, respectively. Even at a high current rate of 15 C, an excellent capacity retention of 91.7% is obtained after 1000 cycles, whilst the high temperature performance was also improved. [ABSTRACT FROM AUTHOR]

• Colloidal optimization in water allows the homogeneous dispersion of small amount (3 wt%) of nanosized nickel within WC powders. • Dispersed nickel decreased the temperature of a dense compact (>95 th%) more than 500 °C. The smaller the size of nickel is, a better effect is observed. • Compacts present equiaxial WC grains with metallic nickel located at the triple points and graphite precipitates within the sample. • Tungsten Carbide with low nickel content (3 wt%) shows hardness and toughness similar to those with a higher nickel content. To soften the extreme sintering conditions of Tungsten Carbide (WC), a 3 wt.% of metallic nickel (Ni) was added to the starting powders. To ensure a fair distribution of the second phase and an intimate mixture of the phases, the colloidal process was adopted. A commercial Ni and a in-house synthesised nanosized nickel were used as sintering aids. Rheological studies allowed a high dispersion of the nickel in the final composite powders. Sintering studies by Hot-Pressing route (HP) proved the great benefices of Ni as a sintering aid, decreasing the maximum temperature necessary to achieve full densification, from 1900 to 1450 °C and dwell times from 20 to 7 min. Among all the materials obtained, the best results in terms of density, microstructure and properties were obtained for WC-nNi, which achieved hardness of 14.8 GPa and toughness comparable to conventional cermets with much higher content of metallic phase. [ABSTRACT FROM AUTHOR]