Clioquinol Research Articles

Effect of TiC particles size on the oxidation resistance of TiC/hastelloy composites applied for intermediate temperature solid oxide fuel cell interconnects

TiC/hastelloy composites are proposed as promising intermediate temperature solid oxide fuel cell (IT-SOFC) interconnects, and the oxidation resistance optimization of composites is crucial for the operation stability of IT-SOFC. Interparticles distance of TiC particles, determined by TiC content and particle size (dTiC), is found to significantly influence the oxidation resistance of composites. For composites with certain content of TiC, as dTiC decreases from 7.22 to 4.40 μm, mass gain (800 °C/100h) increases from 2.54 to 4.02 mg cm−2, while dTiC decreases from 3.10 to 2.21 μm, mass gain reduces from 2.44 to 1.05 mg cm−2. The opposite variation trend is resulted from the different microstructure evolution process of oxide scale as a function of dTiC. Critical d0 is speculated to exist for composites with a given TiC content, and dense TiO2-Cr2O3 layer begins to form on it. To improve the oxidation resistance of TiC/hastelloy composites, dTiC should be much greater (or smaller) than d0 to facilitate the formation of dense NiO (or TiO2-Cr2O3) layer in oxide scale.

Corrosion behaviour of Ni-Cr alloys in wet CO2 atmosphere at 700 and 800 °C

The corrosion behaviour of binary Ni-Cr alloys with 5–30 wt% Cr was studied in Ar-20CO2-20H2O at 700 and 800 °C. Samples were electropolished before exposure to avoid the effect of surface cold work on alloy diffusion. At 700 °C, all alloys underwent both outer NiO formation and internal oxidation. At 800 °C, the alloys containing 5–20 wt% Cr developed non-protective scales, presenting high weight gain kinetics. However, the Ni-25Cr and Ni-30Cr alloys formed a continuous chromia layer, resulting in much reduced corrosion rates. The effects of water vapour on NiO growth, chromia formation and carburization are discussed.

Towards chemically neutral carbon cleaning processes: plasma cleaning of Ni, Rh and Al reflective optical coatings and thin Al filters for free-electron lasers and synchrotron beamline applications

The choice of a reflective optical coating or filter material has to be adapted to the intended field of application. This is mainly determined by the required photon energy range or by the required reflection angle. Among various materials, nickel and rhodium are common materials used as reflective coatings for (soft) X-ray mirrors. Similarly, aluminium is one of the most commonly used materials for extreme ultraviolet and soft X-ray transmission filters. However, both of these types of optics are subject to carbon contamination, which can be increasingly problematic for the operation of the high-performance free-electron laser and synchrotron beamlines. As an attempt to remove this type of contamination, an inductively coupled plasma source has been used in conjunction with N2/O2/H2 and N2/H2 feedstock gas plasmas. Results from the chemical surface analysis of the above materials before and after plasma treatment using X-ray photoelectron spectroscopy are reported. It is concluded that a favorable combination of an N2/H2 plasma feedstock gas mixture leads to the best chemical surface preservation of Ni, Rh and Al while removing the carbon contamination. However, this feedstock gas mixture does not remove C contamination as rapidly as, for example, an N2/O2/H2 plasma which induces the surface formation of NiO and NiOOH in Ni and RhOOH in Rh foils. As an applied case, the successful carbon removal from ultrathin Al filters previously used at the FERMI FEL1 using an N2/H2 plasma is demonstrated.

Differences in the seismicity preceding the 2007 and 2014 eruptions of Kelud volcano, Indonesia

A significant increase in the number of volcano-tectonic (VT) and VB earthquakes preceded the 2007 and 2014 eruptions of Kelud volcano, Indonesia. The background seismicity rates at the volcano is generally <5 of VTs per month and other types of volcanic earthquakes are rarely recorded. After 17 years of quiescence, the 2007 eruption was preceded by an increase in VTs starting in September 2007, two months prior to the eruption. An intense VT swarm began in October 2007 and led to occurrence of VB, sometimes presenting as repetitive self-similar events. The final precursory seismicity included spasmodic bursts of VTs, repetitive self-similar VBs and low frequency tremor, prior to lava dome formation in the crater lake, on November 3, 2007. After just ~6 years, VTs began to increase again in December 2013. The number significantly intensified in mid January 2014, ~1 month before the eruption. Seismicity continued to intensify including VTs, VBs, and LFs into February 2014, with the final precursory seismicity consisting of a burst of over scale tremor, followed by a short burst of repetitive self-similar events that merged into harmonic, gliding tremor a couple hours prior to the explosive eruption on February 13, 2014. We examine the locations of VTs, the energy release rate, and the precursory seismic pattern prior to both eruptions to understand the differences in the eruptions' style and size. We found that epicentral locations of VTs are similar for both eruptions, but the depths were slightly deeper prior to the 2014 eruption. We also find that the cumulative energy released prior to 2014 is twice that of 2007 and in half the time. The migration of VTs in Kelud volcano may indicate magma intrusion from a deeper storage region in 2014 and at a faster rate, leading to a much more explosive eruption.

The Relationship Between Interior Architecture and Music

There is no doubt that there is a calculated relationship between architecture and music. If music is the translation of emotion, this emotion has been reflected in the architectural character and the arts of building and shaping its style. And the music of primitive tribes and barbaric peoples represented by the drums of homogeneous repetitions reflected on their buildings and primitive character or their huts identical and compact without compatibility or homogeneity. The rural music of each country, which is characterized by simple melodies and monotonous tones belonging to the living nature and sprouts from its land, we find a reflection of the buildings that are characterized by simplicity and calm and building materials derived from the surrounding nature.&#x0D; &#x0D; The Harmonized melodies and the continuous repetition of original tones and their background can easily be read or heard on the facades of the Islamic style buildings in the continuous surface repetition of contracts and decorations&#x0D; &#x0D; The change of the personality of Arab architecture from one country to another and the change of the form of contracts and domes, has found a similarity in the changing personality of contemporary music.&#x0D; &#x0D; Every modern development in architecture and its character is recorded by the music and its character. The more the cultures of the peoples are merged, the more modern the modern architecture, which occupies its place in the different countries, resonates with contemporary world music and converges with the civil affinity and culture of the peoples.&#x0D; &#x0D; &amp;quot;Architecture is music embodied in the place,&amp;quot; says Hassan Fathi. &amp;quot;Music is an architecture embodied in time&amp;quot;&#x0D; &#x0D; Studying the relationship between interior architecture and music enables us to &amp;quot;enjoy&amp;quot; it by using our senses to &amp;quot;see what we listen to&amp;quot; and &amp;quot;hear what we see&amp;quot; achieve greater levels of experience. I think this is what the &amp;quot;normal&amp;quot; people do, and they use their senses to live life differently than they did before.&#x0D; &#x0D; Through practical experiments for students of Design 2, the music has been transformed into an interior design through the sensation, sensation and impression of the music in the same designer to translate these feelings into design forms and stereoscopic elements with materials, colors and reflections that express these feelings and the emotional state raised by this music.

The 3D geometry of the Naxos detachment fault and the three-dimensional tectonic architecture of the Naxos metamorphic core complex, Aegean Sea, Greece

We reconstruct the three-dimensional (3D) geometry of the Naxos detachment fault and quantify E–W shortening associated with strong N–S extensional deformation. In addition, 3D reconstruction of the detachment indicates how it interacted with the underlying metamorphic sequence, as well as a set of concentric metamorphic isograds that formed during extensional deformation. For doing so, we used the software MOVE™ (Midland Valley Ltd.) to develop a 3D model of the Naxos metamorphic core complex (NCC) and the Naxos detachment fault. The model is constrained by structural data, metamorphic isograds, and fission-track ages from the footwall of the NCC. Our analysis shows that greater minimum amounts of E–W shortening correlate with higher metamorphic grade, ranging from 6 to 10% outside the migmatite dome and up to 17% within the migmatite dome. The metamorphic isograds around the migmatite dome are less intensely folded by E–W shortening than the lithologic layering. We conclude that this is because the isograd surfaces “froze-in” after folding had already started. Our model indicates that the isograds are cut by the brittle detachment, demonstrating that the final stages of top-to-the-NNE extension outlasted the formation of the metamorphic dome and the isograds. Despite some limitations of the 3D model, the outlined geometric reconstruction of a major extensional fault system in the central Aegean highlights: (1) the interplay between large-scale extension and temperature-dependant shortening perpendicular to the extension direction, (2) the evolution of metamorphism and migmatization, (3) the formation of metamorphic isograds, and (4) granitoid intrusions during extension and exhumation.

Annealing environment effects on the electrochemical behavior of supercapacitors using Ni foam current collectors

Nickel (Ni) foam-based symmetric/asymmetric electrochemical supercapacitors benefit from a randomly 3D structured porous geometry that functions as an active material support and as a current collector. The surface composition stability and consistency of the current collector is critical for maintaining and consistency supercapacitor response, especially for various mass loading and mass coverage. Here we detail some annealing environment conditions that change the surface morphology, chemistry and electrochemical properties of Ni foam by NiO formation. Air-annealing at 400 and 800 °C and annealing also in N2 and Ar at 800 °C result in the in situ and ex situ formation of NiO on the Ni foam (NiO@Ni). Oxidation of Ni to NiO by several mechanisms in air and inert atmospheres to form a NiO coating is subsequently examined in supercapacitors, where the electrochemical conversion through Ni(OH)2 and NiOOH phases influence the charge storage process. In parallel, the grain boundary density reduction by annealing improves the electronic conductivity of the foam current collector. The majority of stored charge occurs at the oxidized Ni-electrolyte interface. The changes to the Ni metal surface that can be caused by chemical environments, heating and high temperatures that typically occur when other active materials are grown on Ni directly, should be considered in the overall response of the electrode, and this may be general for metallic current collectors and foams that can oxidize at elevated temperatures and become electrochemically active.

DUOX1-mediated hydrogen peroxide release regulates sodium transport in H441 bronchiolar epithelial cells.

Dexamethasone has been shown to induce the formation of epithelial domes by bronchiolar H441 cells. It stimulates the expression of both amiloride inhibitable epithelial sodium channels (ENaC) and dual oxidase-1 (DUOX1). We therefore ask the question whether DUOX1 expression and production of submillimolar amounts of H2 O2 is instrumental for the sodium channel upregulation observed in H441 cells. In vitro cell culture, nystatin-perforated whole-cell patch-clamp technique, immunocytochemistry and RT-PCR methods have been used. Cells forming epithelial domes induced by dexamethasone (0.1μmolL-1 , 24hours) and by 5-aza-2'-deoxytidine (1μmolL-1 , 48hours) expressed more DUOX1 protein compared with other cells in the monolayer. Dome formation could be inhibited by exogenous catalase in a concentration-dependent manner and by the NADPH oxidase inhibitor diphenyliodonium, which suggested the involvement of H2 O2 . While single application of 0.2mmolL-1 H2 O2 induced transient dome formation, lower doses were ineffective and higher doses disrupted the cell monolayer. Hydrogen peroxide (0.1mmolL-1 ) activated acutely amiloride-sensitive whole-cell currents from 3.91±0.79pApF-1 to 4.76±0.98pApF-1 in dome-forming cells and had no effect in cells outside of domes. ENaC but not DUOX1 transcription was potentiated by catalase in the presence of dexamethasone, which suggested negative feedback of H2 O2 on ENaC gene expression. Our observations suggest that tonic production of H2 O2 by DUOX1 participates in maintaining the level of vectorial sodium transport by lung epithelial cells. Moreover, the system appears to be well tuned as it would allow H2 O2 -dependent innate immunity without inducing airway/alveolar sodium and fluid hyperabsorption.

Repositioning of 8-hydroxyquinoline derivatives as a new promising candidate for combating multidrug resistant Neisseria gonorrhoeae.

The multidrug resistance of Neisseria gonorrhoeae becomes a public health problem worldwide, especially the strain H041 that showed the decrease susceptibility to ceftriaxone which is the last resort for gonorrhea treatment. Therefore, the simultaneous discovery and development of a new compound to fight this pathogen is urgently required. In this study, 8-hydroxyquinoline (8HQ) and derivatives were evaluated for their antimicrobial activities against the gonococcal pathogen using spectinomycin as the reference drug. The results showed that 8HQ derivatives gave an excellent antimicrobial potency. Particularly, the dihalogenated 8HQ (iodoquinol, clioquinol and 5,7-diCl-8HQ) exerted the high activity with MIC range of 0.08-0.15 μM, 0.10-0.20 μM and 0.28-0.56 µM, respectively, compared with the reference drug (MIC = 16 μg/mL or 48.14 μM). Moreover, these compounds were also shown to be non-cytotoxic/very high safety index. The findings reveal that these three compounds could be further developed as a new antimicrobial agent for fighting the gonorrheal disease.

CEREBRAL ENERGY EXCHANGE AS A MARKER OF ADAPTIVE HUMAN REACTIONS IN NATURAL CLIMATIC CONDITIONS OF THE ARCTIC ZONE OF THE RUSSIAN FEDERATION

The aim of the work was to fix changes of cerebral energy processes in the adaptive reactions of the human CNS in conditions of the Arctic zone of the Russian Federation. Methods. The energy state of the brain was analyzed in different age groups (795 people in total), constantly living in the Arctic zone of the Russian Federation: children 7-10 years old, young people 18-20 years old, elderly people 60-70 years old. Cerebral energy processes were estimated according to the data of the level distribution of the direct constant potential (DC potential) by means of the five-channel hardware-software complex "Neuro-KM". Besides, the level of constant potential was tested in young people (18-20 years) arrived from India to study in the northern university. The reaction of constant potential level on local cooling was determined both in Indian students and students-northerners at the initial training. Results. It was revealed that adaptive reactions of distribution of the brain constant potential level in climate and geographical conditions of the region were characterized by unidirectionality and lack of action specificity, both in natural, and in the simulative conditions irrespective of the age, sex and northern length of service. At the same time reorganization of energy processes finds the reflection in high amplitude of DC potentials of a brain, violation of the dome principle and formation dominance of right hemisphere, both in people constantly living in these territories, and in migrants. Similar changes also happened in local cooling test. Conclusion. Changes of the cerebral energy processes reflecting adaptive reactions of CNS of the person, in particular, distribution of DC potential in a cerebral cortex can be considered as "syndrome of the adaptive surplus of cerebral energy exchange".

The significance of early Permian and early Carboniferous U–Pb zircon ages in the Bossòst and Lys‐Caillaouas granitoids (Pyrenean Axial Zone)

The Axial Zone of the Alpine Pyrenees exposes Ediacaran‐Palaeozoic metasediments and orthogneisses intruded by abundant Variscan granitoids that resulted in elongated HT metamorphic domes separated by tight synforms with low‐grade metasediments. Yet, the age of the granitoids within the metamorphic domes remains debated, hindering the correlation of Variscan deformation stages and the HT metamorphism between the different domes. Here, we dated two granitoids located within classical metamorphic domes using U–Pb LA‐ICP‐MS zircon geochronology: the Bossòst and the Lys‐Caillaouas granitoids in the Garona and Lys‐Caillaouas domes, respectively. The results indicate that the leucogranitic facies of both granitoids have Early Permian crystallization ages at 295 ± 2 Ma and 297 ± 2 Ma, respectively. Furthermore, we found a small population of inherited zircon with Serpukhovian (331–323 Ma) ages in the Lys‐Caillaouas granitoid, reinforcing the existence of an elusive but widespread early Carboniferous magmatic event in the Pyrenees. These ages discard two previous hypotheses explaining the age disparity observed in the different domes: either that the HT‐LP metamorphism is of Visean age only or that the dome formation was diachronous along the Axial Zone, ranging from Visean in the central part to late Carboniferous in the eastern Axial Zone. The early Permian age found in the leucogranitic facies of the Bossòst granitoid questions the proposed Visean age for the formation of the Garona dome and the peak HT‐LP metamorphism and points to an Early Permian age as most likely in line with what is observed in the Lys‐Caillaouas Massif.

IDENTITY, TRADITION AND THE CITY: DICHOTOMIES AND REALITIES OF CREATING AN URBAN LANGUAGE OF THE MALAY PALACE

This paper highlights a case study, its critical issues and the processes encountered in the evolution and development of its urbanised grammar. In deriving a localised language in which traditional forms are fused and transmuted into masonry architecture, the case study of the "Istana Negara" Palace is a case in point. The issues triggered within the design process, including how to represent a universal Malaysian identity reflecting Malay Asian character with Islamic vocabulary are explored. The difficulties and realities of transmuting and integrating such vocabulary to express and configure public masonry buildings are discussed. As an icon for the city, the palace must reconcile its scale with a clear localised vocabulary to fulfil the symbolic nature of the design. The conflicts and dichotomies encountered include three aspects: 1) The dome vs pitch form as an icon for the city (from afar) and the need for a strong roof silhouette 2) the local grammar and language including the pedestal and architrave vocabulary and elements 3) the difficulty of proportionate form. The research points to the necessity and urgency of developing a set of compositional rules and elements of the language of Malay urban architectural identity derived from the essences of tradition and regional form.

IDENTITY, TRADITION AND THE CITY: DICHOTOMIES AND REALITIES OF CREATING AN URBAN LANGUAGE OF THE MALAY PALACE

This paper highlights a case study, its critical issues and the processes encountered in the evolution and development of its urbanised grammar. In deriving a localised language in which traditional forms are fused and transmuted into masonry architecture, the case study of the "Istana Negara" Palace is a case in point. The issues triggered within the design process, including how to represent a universal Malaysian identity reflecting Malay Asian character with Islamic vocabulary are explored. The difficulties and realities of transmuting and integrating such vocabulary to express and configure public masonry buildings are discussed. As an icon for the city, the palace must reconcile its scale with a clear localised vocabulary to fulfil the symbolic nature of the design. The conflicts and dichotomies encountered include three aspects: 1) The dome vs pitch form as an icon for the city (from afar) and the need for a strong roof silhouette 2) the local grammar and language including the pedestal and architrave vocabulary and elements 3) the difficulty of proportionate form. The research points to the necessity and urgency of developing a set of compositional rules and elements of the language of Malay urban architectural identity derived from the essences of tradition and regional form.

Liquid hydrocarbon production via ethylene oligomerization over Ni-Hβ

We carried out oligomerization of ethylene using nickel supported on an acidic zeolite β (Ni-Hβ) catalyst in a laboratory-scale packed bed reactor for the synthesis of liquid hydrocarbons in milliliter quantities. We evaluated the effect of several process variables (temperature, pressure, weight hourly space velocity (WHSV), and nickel loading) on the ethylene conversion, liquid hydrocarbon/coke yield, and oligomeric product selectivity. Increases in pressure resulted in higher ethylene conversion, leading to a liquid yield of 13.0 wt%, with 10.0 wt% coke at 65 bar. As the pressure increased to 65 bar, the selectivity towards octenes reached 10%, along with a decrease in C4 to 34%, which suggested that higher pressures promoted butene dimerization. Under the conditions studied, a minimum temperature of 120 °C was required to produce liquid hydrocarbons. The liquid yield increased with temperature, with a maximum of 17.0 wt% at 190 °C. Higher temperatures led to the formation of odd-numbered oligomers primarily due to acid-catalyzed cracking reactions. In the range of WHSV tested, a moderate 2.0 h−1 resulted in a local maximum of 10.6 wt% of liquid hydrocarbon yield. A moderate nickel loading of 3.4 wt% also resulted in the highest liquid yield (10.6 wt%) out of the three loadings tested. The results strongly suggest that the ionic form of nickel is much more active catalytically than the NiO form. The variation in nickel loading revealed the importance of having a synergistic balance of nickel and acid sites on the catalyst to maximize ethylene conversion and maintain high liquid hydrocarbon yield. The results from this work formed the basis for pilot scale runs carried out at the Southwest Research Institute (SWRI) for the Advanced Hardwood Biofuels (AHB) project. The pilot runs highlighted the need for efficient removal of ethanol from the ethylene feed after the dehydration process.

Three-Dimensional Predominance Volume Diagrams: The Ni-As-S-O System

The 3D predominance volume diagram (PVD) for the Ni-As-S-O system at 700 K (427 °C) was constructed using independent gases O2, SO2, and As4O6. The system has 15 four-condensed-phase invariant points. Invariant points, fixed by any combination of boundaries and condensed phases totaling four, were determined by a Gibb’s minimization routine that searched from a corner of the PVD along each undetermined line emanating from this and subsequently-identified invariants. The search direction was determined from the cross product of the two independent planes’ normal direction vectors. The 0.25 atm and 1.00 atm isobaric surfaces intersect the Ni3As2O8, NiO, NiSO4, Ni1−xS, NiS2, and Ni11As8 phases. The 1.00 atm surface also intersects the NiAs phase. The PVD results agree with published ternary and quaternary phase diagram Alkemade lines. If the roasting of gersdorffite (NiAsS) parallels the roasting of enargite (Cu3AsS4), gersdorffite is expected to initially react irreversibly with O2 in the roasting gas to form NiS and NiSO4 topochemical layers with arsenic being expelled as As4O6 gas and perhaps As4 gas once a diffusion-controlled topochemical reaction sequence is established. Thermochemical calculations showed that the formation of NiO from NiSO4 and Ni3As2O8, if present, becomes more favorable as the temperature is increased with complete conversion to NiO above 1086 K and 1160 K (813 °C and 887 °C), respectively, at 1.00 atm.

High efficient electron field emission from rGO conformally coated NiO nanoflakes architecture

In the study, we report the facile synthesis of reduced graphene oxide (rGO) conformally coated vertically aligned, densely packed NiO nanoflakes (NFs) architecture for high efficient electron field emission applications. The NiO NFs architecture was grown on the Si substrate by a simple hydrothermal method, followed by decoration with rGO by drop casting method. The grazing incidence X-ray diffraction measurements reveal the formation of cubic structured NiO. The grown NiO NFs architecture is in better stoichiometry as evidenced from the resonant Rutherford backscattering spectrometry measurements. The rGO conformally coated NiO NFs (GNiO NFs) shows higher mobility and lower sheet resistance in comparison with its counterparts. X-ray absorption near edge structure analyses at O K-edge reveals the increase in unoccupied density of states due to the charge transfer from NiO to rGO. The rGO conformally coated NiO NFs architecture exhibits low turn-on voltage and enhanced field emission (FE) current as compared to the NiO NFs architecture. The observed low turn-on voltage and enhanced FE current for the GNiO NFs architecture is ascribed to the synergistic effect of addition of rGO as the conductive channels, which results in better charge transport and the enhanced field emission current characteristics.

Plutons and domes: the consequences of anatectic magma extraction—example from the southeastern French Massif Central

Anatectic magmas form plutons or accumulate in the core of anatectic domes. Both scenarios have distinct implications on the behaviour of the continental crust during orogenic evolution from collision to collapse. Considering a stepwise extraction of melt, we simulate the evolution of anatectic melt and of solid residues produced in the crust from collision to collapse using thermodynamic modelling. We also simulate the effect of entrainment of source material (restite-unmixing and peritectic assemblage entrainment) on the compositional range of the resulting magmas. The results are then compared to the compositions of lower crustal xenoliths and of peraluminous granites in both plutons and anatectic dome in the southeastern French Massif Central (SE-FMC). From our calculations, we identify two type of anatectic melts (1) cool-and-wet produced at low-temperature ( 750 °C) which only release fluids at the end of crystallisation. When emplaced around 0.4 GPa, cold-and-wet melts are produced by muscovite-dehydration melting reactions; hot-and-dry are produced by biotite-dehydration melting. In the SE-FMC, the Velay dome is cored by the Velay granite, intruded by small bodies of Velay leucogranite and surrounded by plutons made of either two mica leucogranite (MPG) or cordierite-bearing granite (CPG). MPG and Velay leucogranite compositions are best reproduced by cool-and-wet magmas. CPG and Velay granite compositions are best reproduced by hot-and-dry magmas. Melt extraction after biotite dehydration melting leaves residues that are similar in composition to lower-crustal xenoliths. Magmas forming plutons migrate freely toward the upper crust forming plutons with distinct compositions. On the contrary, to form a dome, magmas are retained on the way up. The emplacement and accumulation of magma at deeper level enhances (or trigger) melting due to the addition of heat (from hot-and-dry) and fluids (from cool-and-wet). The accumulation of magma and the in situ melting increases melt fraction and has consequence to weaken the middle crust and leads to the formation of an anatectic dome. We suggest that magmas are retained due to lithological heterogeneities in the crust. In the case of the Velay dome, a large orthogneiss formation similar to the Velay orthogneiss formation may have played that role.

Room and elevated temperature sliding wear behavior of cold sprayed Ni-WC composite coatings

The tribological properties of cold sprayed Ni-WC metal matrix composite (MMC) coatings were investigated under dry sliding conditions from room temperature (RT) up to 400°C, and during thermal cycling to explore their temperature adaptive friction and wear behavior. Characterization of worn surfaces was conducted using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and Raman spectroscopy to determine the chemical and microstructural evolution during friction testing. Data provided insights into tribo-oxide formation mechanisms controlling friction and wear. It was determined that the steady-state coefficient of friction (CoF) decreased from 0.41 at RT to 0.32 at 400°C, while the wear rate increased from 0.5×10−4mm3/N·m at RT to 3.7×10−4mm3/N·m at 400°C. The friction reduction is attributed primarily to the tribochemical formation of lubricious NiO on both the wear track and transfer film adhered to the counterface. The increase in wear is due to a combination of thermal softening of the coating and a change in the wear mechanism from adhesive to more abrasive. In addition, the coating exhibited low friction behavior during thermal cycling by restoring the lubricious NiO phase inside the wear track at high temperature intervals. Therefore, cold sprayed Ni-WC coatings are potential candidates for elevated temperature and thermally self-adaptive sliding wear applications.

Terrace site hydroxylation upon water dimer formation on monolayer NiO/Ag(100)

The interaction of water vapor with monolayer NiO/Ag(100) was examined using both experimental and computational techniques. Initial film growth was characterized by scanning tunneling microscopy and low energy electron diffraction showing the formation of NiO(1 × 1). X-ray photoelectron spectroscopy (XPS) reveals that the initial film was mainly composed of NiO oxide with a small amount of hydroxyl groups (OH) attributed to the dissociation of background water vapor at highly reactive edge sites. Density functional theory (DFT) reveals that the adsorption of a water monomer on NiO/Ag(100) terrace sites prefers to be in the molecular rather than the dissociate state. XPS results indicate that upon exposing the oxide film to high water vapor pressures (maximum 333.3 Pa), extensive hydroxylation occurs which is attributed to water dissociation at terrace sites. DFT reveals that upon aggregation of water monomers to dimers at the oxide interface the dissociated dimer is energetically stable. The results herein are consistent with previous MgO/Ag(100) studies, further revealing that for certain metal oxides the formation of water dimers at the metal oxide-vapor interface is a key mechanism leading to extensive terrace site hydroxylation.

Synthesis of mesoporous triple-metal nanosorbent from layered double hydroxide as an efficient new sorbent for removal of dye from water and wastewater

In this study, co-precipitation synthesis of the mesoporous triple-metal nanosorbent from Fe, Cu, Ni layered double hydroxide (FeCuNi-LDH), on the basis of the data obtained from the TG analysis was carried out. The FTIR spectroscopy and XRD results confirm the formation of CuO, NiO and Fe2O3 nanoparticles, while the EDX analysis does not show significant variations on the surface in elemental composition. BET analysis shows that FeCuNi-280 (FeCuNi-LDH calcinated at 280 °C) with mesoporous structure, has larger surface area compared to FeCuNi-LDH and FeCuNi-550 (FeCuNi-LDH calcinated at 550 °C). The value of pHPZC of FeCuNi-280 is found to be 8.66. Obtained FeCuNi-280 material showed the ability for efficient removal of dye Reactive Blue 19 (RB19) from water, with a very high sorption capacity of 480.79 mg/g at optimal conditions: the sorbent dose of 0.6 g/dm3, stirring speed of 280 rpm and pH 2. The kinetics results of the sorption process were well fitted by pseudo-second order and Chrastil model, and the sorption isotherm was well described by Sips, Langmuir and Brouers–Sotolongo model. FeCuNi-280 was easily regenerated with aqueous solution of NaOH, and reutilization was successfully done in five sorption cycles. The present study show that easy-to-prepare, relatively inexpensive nanosorbent FeCuNi-280 is among the best sorbents for the removal of RB19 dye from water solution and wastewater from textile industry in wide range of pH.