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Wollastonite nanopowder (β-CaSiO3) is the most nanoceramic powder that is most frequently applied in biomedical applications due to its good bioactivity and biocompatibility. Although the preparation of wollastonite in a solid-state is distinguished as a simple and cheap method with large-scale production, it requires high temperatures (=1400 °C) and consumes quite a long time. The wet methods are considered the best when it comes to preparing the wollastonite nanopowders. However, it has some drawbacks such as its extravagant raw materials and its shorting in preparation which inhibits successful coverage for large-scale production. Herein facile, one-pot modified co-precipitation approach with an easy procedure, shorter reaction time, and in-expensive precursor sodium meta-silicate-pentahydrate and CaCO3 has been utilized for large-scale production of wollastonite nano-powders (76–150 nm). The precipitated product was calcined at different temperatures (800, 900, 1000, and 1100 °C). The phase composition and microstructure of the calcined powders were investigated. They were analyzed by XRD, FTIR, FESEM, and HRTEM. The in-vitro bioactivities of the calcined powders at 1000 &1100 °C were investigated by analyzing their abilities to form apatite on their surface after 21 days in SBF. The apatite mineralization of the powder surfaces was examined through FESEM, EDX, and Raman spectra. The results show that a single-phase wollastonite got formed at all calcined temperatures with a unique silkworm texture. SBF in-vitro test states the formation of HA on the powder surface. Therefore, these powders are expected to be valuable and promising for biomedical applications such as coating and bio cement.

High-performance harvesting of waste heat energy and its conversion into electric energy via thermo-electrochemical cells is an essential strategy of renewable energy development. Even though there is a large amount of scientific research available, but due to expensive electrode materials and low efficiency, the thermo-electrochemical cells have not found practical application. Here we demonstrated thermo-electrochemical cell with nickel (Ni) hollow microspheres-based electrodes, provided the highest hypothetical Seebeck coefficient of 4.5 mV/K (for aqueous electrolyte based thermocells) until today and open-circuit voltage values of up to 0.2 V. High values of Seebeck coefficient provide the ability to collect low-temperature heat, and high output potential differences which allow to fabricate batteries for commercial power circuits for various microelectronic devices. This work also proposed a mechanism and science behind the electrode processes, which explains a extremely high values of the hypothetical Seebeck coefficient. This is the first time to use Ni hollow microsphere in thermo-electrochemical cell for heat harvesting and thermal energy conversion into electricity. Because of the low cost of Ni microspheres electrode-based developed thermo cells could be commercially feasible for harvesting low-quality thermal energy.

A new route of purification/revalorization of nickel electroplating wastewaters is proposed. It is shown that chemical treatment of different nickel-electroplating wastewaters with aqueous dispersion of layered structure amorphous potassium polytitanate (PPT) successfully removed the nickel from the effluents. Moreover, the resulting solid products, obtained with optimal PPT doses, showed excellent and consistent photocatalytic properties in the visible range of solar radiation, which are independent on the characteristics of the wastewater i.e. pH, nickel contents or the presence of other heavy metals. On the other hand, after proper dilution, the resulting treated effluents can be returned to the municipal wastewater collectors. The mechanisms of the processes taking place during the treatment are analyzed.

A green combustion method using Aloe vera latex as a fuel was employed to synthesize nanocrystalline cupric oxide (CuO). The nanocrystalline nature and phase of CuO was confirmed by powder X-ray diffraction. Applying the Kubelka–Monk function to diffuse reflectance spectra showed the band gap of CuO to be 1.632 eV. Paracetamol and d -glucose in 1 M KOH solution were sensed using a carbon paste electrode modified using CuO nanoparticles (NPs). The cyclic voltammetry results suggest that CuO NPs possess superior electrochemical properties due to a lower value of the difference between oxidation and reduction potential (EO-ER). The proton diffusion coefficient for CuO electrode material was1.5047 × 10−5cm2s−1. Electrochemical impedance and Bode studies confirmed that the charge-transfer resistance value of CuO NPs was on the lower side due to the phase angle (55°) being near to ф = ᴨ/2. The electrochemical behavior indicates that CuO is a promising electrode material for sensing molecules such as paracetamol and glucose.

Graphene and graphene oxide (GO) both being two-dimensional materials are gaining popularity among researchers as a promising nanomaterial for various medical and biological applications. The aim of this study is to elucidate the influence of nanostructured GO sheets on viability of a model species of gram-negative E. coli bacteria transformed with pRSET-emGFP plasmid in in vitro experiments. It was shown that GO at concentrations between 0.0025 and 2.5 g/l in growth medium inhibits growth of bacterial colonies, while in physiological saline solution (PS) this effect decreases dramatically to the point of complete disappearance. It was shown that in order to obtain a pronounced antibacterial effect one needs to introduce high concentrations of GO into the media (up to 2.5 g/l), which can be important for development of antibacterial materials for biomedical applications. Some of the obtained data provide clear evidence to electrostatic nature of interaction between bacterial and GO sheets. A number of previous papers suggested the process of biofilms formation by bacteria as the primary reason for aggregation between graphene-like materials and bacterial cells. However, formation of flocculent structures consisting of GO and dead bacteria and accompanied with decrease in zeta-potential of particles in the suspension to 18 mV proves that electrostatic interactions play the major role in aggregation. The obtained data can be used for employing GO and similar materials in new systems for water-purification from biological contaminants. Besides, our results stress the importance of accounting for the conditions in which goods and coatings containing graphene-like materials as an antibacterial agent are used, as well as unification of the experimental conditions.

In spite of good development and progress in lubricants, billions US dollars are being lost in many industries and motor vehicles globally due to engine frictions. Therefore, there is a great need to develop more efficient and effective lubricants. Many people modified lubricants by using nano materials, which seems to be a bright future. The present review paper considers the application of carbon nanostructures, such as carbon nanotubes and graphene, as nano-additives to lubricants in order to improve their tribological characteristics i.e. to decrease friction and wear. Some important aspects of nanoparticles in modifying lubricants are size, form, structure, surface functionalization, concentration, physical and chemical properties of surfaces, which are outlined in this article. It was observed that the adding of nano-additives to lubricants; even at low concentrations; considerably decreased the friction and wear coefficients. Moreover, carbon nanotubes and graphene are environmentally friendly and safe. Thus, all these factors allow positive assessment of the prospects of using the abovementioned nanomaterials to modify lubricants. The present article will be useful for the researchers and industrial persons.

MAX phases (M: early transitionA:13 and 14 group A-element; X:C and/or N) are ternary carbides/nitrides with a unique combination of metallic and ceramic properties. Bulk MAX phases can be prepared from different starting materials and pre-synthesized powders mostly at high temperature and long sintering time. Here, we prove an efficient one-step technological method to produce bulk MAX phase based materials using self-propagation high-temperature synthesis. We show that bulk materials (relative density of 95.5% and 97.2%) can be produced in the form of plates and rods with 67.5% wt. and 81.9% wt. of MAX phases. The compressive strength of 720 ± 2 and 641.5 ± 2 MPa Young's modulus of 221.5 ± 4 and 198.3 ± 2.8 GPa, and thermal conductivity of 22.9 and 22.3 W m−1 K−1 are achieved as a result of extrusion and compression self-propagation high-temperature synthesis. The sintered materials are good thermal conductors with high mechanical characteristics that can be used as promising materials for high-temperature application.

A Cu(II) based metal–organic framework (MOF), [Cu2(TPT)2(BTC)Cl]·(solvent)x, (TPT = 2,4,6-tris(4-pyridyl)-1,3,5-triazine, BTC = benzene-1,3,5-tricarboxylic acid) has been solvothermally synthesized and characterized using single crystal X-ray diffraction, powder X-ray diffraction, thermogravimetric analysis and magnetic measurements. This compound adopts three-dimensional connectivity where Cu2+ dimers are linked with BTC ligand to form the layered architecture. This layered motif is pillared by TPT linker to form the three-dimensional structure. Magnetic studies show that the compound undergoes a magnetic long-range ordering at TN ≈ 5 K. A large value of Curie–Weiss temperature compared to TN suggests strongly frustrated nature of the magnetic compound.

Mesoporous carbonated hydroxyapatite (HAp) with different size, shapes, and the specific surface area has received much interest in various biomedical applications. In this study, we reported a rapid microwave-assisted hydrothermal amalgamation of mesoporous carbonated HAp with tunable nanoscale characteristics using organic modifiers such as oxalic acid and sodium dodecyl sulfate (SDS) as a regulator. The synthesized HAp was analyzed to obtain its physiochemical properties using different characterization techniques to figure out its crystallization nature, particle size, phase purity, elemental composition, pore size, pore volume, and particle size distribution. The observed results clearly showed that the mesoporous carbonated HAp with tunable nanoscale characteristics can be achieved through a microwave enabled hydrothermal digester with the aid of organic modifiers. Moreover, it was found that the addition of oxalic acid during the synthesis can make strong interaction with calcium ions which resulted in the HAp along with calcium oxalate phase whereas the addition of SDS leads to pure HAp phase. Oxalic acid-mediated synthesis leads to form loosely agglomerated rod-like mesoporous nanoparticles having 10 nm width and 20–40 nm length with a specific surface area of 89 m 2 g −1 while SDS-mediated synthesis leads to form nanorods bearing 20–45 nm of width, and 55–100 nm of length with specific surface area of 48 m 2 g −1 . In addition, oxalic acid and SDS also help in tuning the pore size and pore volume by making interaction with HAp crystallites during the synthesis process. Thus, oxalic acid and SDS can plays an important role in modifying structural and physiochemical properties of HAp and it can be used to produce mesoporous HAp nanoparticles through microwave enabled hydrothermal digester for different biomedical applications.

Hollow structured mixed metal oxides (MMOs) with porous outer shell have recently been emerged as advantageous candidates for energy conversion and storage applications due to their outstanding electrochemical properties. In this report, the novel bi-component-active hollow CoFe2O4@Fe3O4 nanospheres with the mesoporous outer shells (HCFO-POS) were successfully prepared by ultrasonic spray pyrolysis method. The as-synthesized HCFO-POS was evaluated as an anode material for lithium-ion battery (LIB), it exhibits excellent electrochemical properties for lithium storage. To be specific, it can deliver a decent specific capacity of 365 mAh g−1 even at a high current density of 1000 mA g−1 with cycling stability up to 500 cycles. The aforementioned excellent performance of this HCFO-POS electrode can be explained based on i) unique mesoporous nature which could buffer the volume change, shorten the diffusion path of Li+ ions during the lithiation/delithiation process, enhances the effective contact area between electrolyte/electrode interface and finally. ii) synergistic effect of mixed metal oxides which helps to improve the conductivity of the electrode.

In an attempt to solve one of the most critical global concerns of energy resources depletion, the present work is focused on tailoring and processing of a new volumetric receiver material for solar energy and high temperature applications. This in turn support producing a highly qualified solar receiver material for the future energy and electricity supply of Middle East and Europe. Herein, the processing and studying of the different parameters affecting on the preparation of near fully dense SiC/AlN structures and investigation of their different characteristics were achieved. These ceramic composites will constitute the final foam struts of the pores of the volumetric air receiver. Various SiC/AlN composites were designed with different ratio of AlN content (0–40%) and produced via pressureless sintering. Influence of different parameters on sintering and densification of SiC/AlN composites such as sintering atmosphere, additives and temperature were investigated in order to achieve the required and qualified properties of the final product of proposed SiC/AlN solar receiver. The quality and performance of the produced composites were evaluated and analyzed through different investigations, including XRD, densification parameters, microstructure examination and thermal properties. The results show that the best sintering conditions for producing a highly dense and qualified carbide/nitride receiver was attained at a temperature of 2080 °C in argon/vacuum with 2.5%Y + A addition. The characteristics of the investigated composites were mainly dependent on their densification behavior and AlN content. Thermal conductivity, diffusivity and coefficient of thermal expansion gave enhanced values at high temperatures. The inspected SiC/AlN composites can be strongly nominated to be used in solar energy applications.

In this paper, we report the sono-synthesis of reduced graphene oxide (rGO) using polyethyleneimine (PEI), and its performance for ammonia vapour detection at room temperature. Graphene oxide (GO) and reduced graphene oxide (rGO) were prepared by sonication method by using low-frequency ultrasound under ambient condition and films were deposited by Doctor Blade method. The rGO, which has vapour accessible structure showed a good sensing response with a minimum detection limit of 1 ppm and the detection range from 1 ppm to 100 ppm. The sensing response was found to be 2% at 1 ppm and 34% at 100 ppm of ammonia and the developed sensor operated at room temperature. The sensor displays a response time of 6 s and a recovery time of 45 s towards 100 ppm of ammonia vapour. The source for the highly sensitive, selective and stable detection of ammonia with negligible interference from other vapours is discussed and reported. We believe reduced graphene oxide (rGO) could potentially be used to manufacture a new generation of low-power portable ammonia sensors.

Blast furnace slags are a by-product resulting from the production of pig iron that can be used as partial cement replacement materials. However, latent hydraulic properties and a low chemical activity of slags limit their wide application. Here, we demonstrate some methods for slag activation using electromagnetic vortex milling and alkaline activation. We show that slag powder with an average particle size of 8 μm and a specific surface area of 2.4 m 2 /g is achieved at “slag/ferromagnetic elements” ratio of 1:2 and the processing time of 5 min in the electromagnetic vortex mill. The using of a 5 M sodium hydroxide solution stimulates the dissolution of the slag and results in the average 28-days compressive strength of a cement of 45.8–59.8 MPa.

The lithium storage properties of hollow ZnO/Cu2MgO3 nanocages with porous outer shell as an efficient anode material for next generation lithium-ion battery (LIB) are demonstrated for the first time. The ZnO/Cu2MgO3 nanocages as anode material are synthesized by one-step cost-effective ultrasonic spray pyrolysis method. The porous outer shell with hollow interior not only offer ease of electrolyte diffusion and fast Li-ion transport, but also buffer the huge volume change during repeated lithiation/de-lithiation process. As a result, this novel anode demonstrates a high discharge capacity (441 mA h g-1 at the current density of 500 mA g−1 even after 400 cycles), excellent cycle stability, and outstanding rate capability.

This work inspects the effect of different sintering atmospheres on the microstructure behavior and grains morphology of pressureless sintered SiC/AlN ceramic composites. Different SiC/AlN composites with different AlN content (0–40 wt%) were prepared by pressureless sintering at 2080 °C/2 h with addition of 2.5 wt% yttria and alumina as sintering aids. Microstructure investigation of the different carbide/nitride composites were studied under two different sintering atmospheres of argon (Ar)/vacuum and nitrogen (N2)/vaccum. Densification parameters of the different composites were measured and evaluated. Results showed that, SiC/AlN composites gave homogenous microstructure with expected high temperature properties. However they manifested different demeanors under the different atmospheres. Sintering of different composites in Ar/vacuum atmosphere was found the most suitable with high density and harmonic structure. Cold crushing strength (CCS) of the composites of the chosen atmosphere was studied and analyzed. Different SiC/AlN composites gave superior strength values resulted from the good bonding and diffusion between SiC and AlN besides their solid solution reaction. Results suggest using the investigated composites in aggressive high mechanical and high temperature applications.

This paper provides a detailed study of the thermoelectric properties of SiC/AlN composites in a wide temperature range. Evaluation of thermal stress durability of the composites was simulated and analyzed. SiC/AlN composites with 0–30 wt% of AlN were produced by the pressureless sintering method. Phase analysis, densification, and microstructure of the obtained composites were inspected. SiC/AlN ceramics had a porous structure with porosity ranging from 23.77% to 31.74%. Complete 2Hss SiC/AlN solid solution was formed and its content increased with the increment of AlN wt%. Addition of AlN to SiC ceramics gave a harmonic structure with elongated grains morphology. Electrical resistivity and thermoelectric properties of the investigated ceramics were evaluated in the temperature range of 25–1000 K. The results were essentially dependent on AlN content, microstructure and temperature. SiC/AlN composites gave identical behavior of the p-type semiconductors with outstanding thermoelectric properties at high temperatures. The lowest electrical resistivity of 1.5 × 105 µOhm × cm and the highest Seebeck coefficient of 370 µ V/K were recorded for 30% AlN composite at 1000 K. Figure of merit (ZT) increased dramatically with increasing the AlN content. 30% AlN composites recorded ZT value 130 times larger than that of the 0% AlN composite. Thermoelectric power factor was markedly enhanced by increasing AlN wt%. Thermal stress analysis of the different ceramics was simulated by finite element method up to a temperature of 1773 K. SiC/AlN composites gave splendid thermal stress durability with uniform transition and distribution of heat. SiC/AlN composites are strongly nominated to be used effectively in thermoelectric power generation and high-temperature applications.

Porcelain stoneware tiles are materials with excellent technical properties processed by using high temperatures and fast firing cycles that requires high-quality fluxes. However, high cost and exhaustive reserves of traditional used feldspars limits their use. The study of the fluxing potential of granitic rock wastes and basalts and their effect on properties and microstructure of porcelain tiles was carried out. The addition of the basalt in the amount of 7.5 wt% leads to the best densification behavior and near-zero water absorption of the samples. The properties of porcelain tiles with addition of basalt and granitic rock wastes show the possibility of their limit use as fluxes in ceramic tiles industry.

We report the rapid microwave-assisted hydrothermal synthesis of mesoporous hydroxyapatite (HAp) nanocrystals with controlled size, morphology, and surface area using various organic modifiers as regulators. The products were analyzed for their crystalline nature, phase purity, morphology, particle size and pore size distribution. Results indicated that ascorbic acid, cetyltrimethyl ammonium bromide (CTAB) and polyvinylpyrrolidone (PVP) play an important role to obtain needle like, rod like and fiber like mesoporous HAp nanocrystals with different specific surface area by controlling growth habit of HAp along c -axis. In addition, the prepared samples were B-type carbonated HAp similar to bone minerals. Therefore, the present approach can be a promising way to obtain precursor for making tissue engineering scaffolds, drug/protein delivery carriers and bone fillers with tunable characteristics.

Nanostructured magnetic cobalt microspheres were synthesized using a two-stage method. First, nanostructured cobalt oxide Co3O4 microspheres were produced by ultrasonic spray pyrolysis at different temperatures from 800 to 1100C. Second, the nanostructured powders obtained were reduced to metal cobalt in an hydrogen atmosphere at different temperatures from 220 to 350C. In this study the evolution of the morphology from Co3O4 nanostructured microspheres to nanostructured Co, resulting from the Co3O4 reduction process, and the structure of metal cobalt, were investigated. It was found that the metal cobalt agglomerates have the same shape and mean diameter (∼ 1,5 μm) as those of the cobalt oxide, Co3O4. The amount of Co microspheres with smaller diameters decreased with increasing reduction temperature. Also, the β-Co content increased with increasing reduction temperature.

The hollow NiCo 2 O 4 nano-spheres (∼300–500 nm) are synthesized by ultrasonic spray pyrolysis method and used as electrode for high-performance supercapacitor (SC) and lithium-ion battery (LIB). When used in SC application, the hollow NiCo 2 O 4 deliver a specific capacitance of ∼1000 F g −1 even after 3000 charge–discharge cycles. In addition, as an anode material for LIBs, it exhibits admirable high capacity values of 763 and 516 mA h g −1 after 1000 cycles at a current density of 1500 and 3000 mAh g −1 , respectively. The excellent electrochemical performance of this hollow NiCo 2 O 4 nano-sphere indicates its potential applications for next generation SCs and LIBs.

A new nanocomposite has been prepared embedding CuO nanoparticles as an additive into grafted β-nickel hydroxide electrode and their electrochemical performance in KOH electrolyte have been investigated. β-nickel hydroxide (β-Ni(OH)2) has been prepared by a simple precipitation method. Ni(OH)2/NiOOH, the main active materials in the pasted nickel electrode have been prepared using nickel mesh in the form of current collector. A study on the electrochemical performances of the pure β-Ni(OH)2 and CuO added β-Ni(OH)2 electrodes in 6.0 M KOH electrolyte has revealed that CuO embedded β-Ni(OH)2 displays much higher specific capacitance and better cyclability than pure β-Ni(OH)2. In fact, the addition of CuO improves the reversibility of the electrode by reducing the anodic (Epa) and cathodic (Epc) peak potential difference and also increases the separation of the oxygen evolution (EOE) and anodic (Epa) peak potential. Further, CuO nanoparticles grafted β-Ni(OH)2 electrode displays elevated proton diffusion co-efficient (D) and inferior charge transfer resistance. Specifically, CuO embedded β-Ni(OH)2 exhibits 855 F g−1 at 5 Ag-1 and good cycling stability as it maintains more than 90% of its original capacitance even after 3000 cycles. The enhancement may be attributed to the nanosize of CuO and chemical interaction between CuO and β-Ni(OH)2. These results are expected to offer new insight to future researchers who wish to work on the development of novel electrode materials for energy storage applications.

Pool boiling heat transfer in capillary-porous coatings was experimentally studied using two coolants (water and liquid nitrogen) at atmospheric pressure. The unique type of capillary-porous coatings with different thicknesses (400–1390 μm), morphology and with high porosity (up to 60%) were fabricated by the directional plasma spraying technique. The study shows that the use of capillary-porous coatings leads to significant enhancement of heat transfer up to 4 times at boiling of liquid nitrogen and up to 3.5 times at boiling of water in the region of low heat fluxes. Based on the analysis of high-speed video, it is shown that the mechanisms of heat transfer enhancement can differ substantially depending on the properties of liquid and morphology of coatings. The enhancement factor for the developed capillary-porous coatings is compared with the results of previous studies obtained using the structured surfaces with re-entrant cavities, microchannels and coatings fabricated by the gas-thermal methods.

This study is focused on finding a versatile approach for obtaining low cost, lightweight composites with high thermal conductivity and good mechanical properties at the same time. The most promising application for such material is to replace fabric reinforced laminates in circuit board production. We used high density polyethylene (HDPE) as a polymer matrix and two types of hexagonal boron nitride (hBN) powders with average particle size 2–5 μm and 120–140 nm as a functional filler. To improve both filler-matrix adhesion and mechanical properties of the composites we used one of two techniques: treating the filler with silane coupling agent before composite processing or using titanate coupling agent in the process of roller-mixing. The study showed, that while the best thermal conductivity of 2 W/m K was achieved on the sample prepared without any coupling agent the sample was too brittle for further processing. On the other hand the sample with KR TTS additive and HDPE to hBN ratio 1:1 showed quite high ultimate strength of 24.8 MPa coupled with high Young's modulus, good elongation at break and thermal conductivity of 0.9 W/m K. Usage of hBN nanopowder as a filler resulted in good mechanical properties and high elongation at break values with thermal conductivity values significantly lower than for micro-sized fillers (0.43 W/m K).

The perovskite solar cell technology is showing rapid progress in delivering high power conversion efficiency. This is not limited to conventional 1 SUN illumination, but state-of-the-art results have also been also demonstrated for a low-light condition such as indoor illumination. In this work, we show that very efficient low-light perovskite solar cells can be realized in the inverted configuration with the use of NiO as a hole transporting material by employing a conventional high-temperature process (300 °C, compact NiO) or a low-temperature process (

Novel hollow-structured Cu0.4Zn0.6Fe2O4 porous negative electrode material is synthesized using a one-step spray pyrolysis method, which exhibits excellent rate capability, high cycling stability, and fast charge-discharge performance in Li-ion batteries. Evaluation of lithium storage properties reveals that the hollow Cu0.4Zn0.6Fe2O4 nanospheres exhibit high specific capacity of 1122 mAh g−1 at a current density of 100 mA g−1, excellent rate capabilities up to 1500 mA g−1 and long term cycling stabilities at a high rate of 1000 mA g−1. Interestingly, the hollow cavity and porous textures of the Cu0.4Zn0.6Fe2O4 anode are well retained even after 1000 cycles at 1000 mA g−1. The synergistic effect among the different cations, as well as the nano-dimension coupled with a hollow interior and surface porosity of the electrode materials, not only facilitate Li-ion and electron transportation kinetics but also accommodate large volume expansion.

In this article, for the first time, we are reporting on the electrochemical lithium storage properties of hollow Mg 0.25 Cu 0.25 Zn 0.5 Fe 2 O 4 /NiFe 2 O 4 nanocomposites. The nanocomposites exhibit excellent cycling performance with a capacity of 661 and 460 mA h g −1 after 500 cycles at a very high rate of 300 and 1000 mA g −1 , respectively. Such superior performance over other Fe based mixed metal oxides is produced by the combination of the composite and the hollow structures. In virtue of the excellent electrochemical performance, hollow Mg 0.25 Cu 0.25 Zn 0.5 Fe 2 O 4 /NiFe 2 O 4 nanocomposites have huge potential as anode materials for the next-generation lithium ion batteries.

In the relentless pursuit of finding new electrode materials for lithium ion batteries (LIBs), mixed metal oxides (MMOs, containing different metal cations), have confirmed improved electrochemical activities in comparison with simple metal oxides (SMOs, containing single metal cations). On the other hand, electrodes with nano-dimension and hollow microstructure have been confirmed as advantageous candidate in LIBs. The integration of the two features into one structure can provide another chance to improve the lithium storage capabilities. In this work, for the first time we report the lithium storage property of porous Cu0.10Mg0.40Zn0.50Fe2O4/Ca2Ni5 nanocomposite as LIB anode. The nanocomposites anode delivers approximately 350 mAh g−1 after 500 cycles at 300 mA g−1. Even at a high rate of 1000 mA g−1, it also showed an excellent performance up to 1000 cycles and 90% Coulombic efficiency with no sign of capacity fading. This outstanding Li storage performance makes Cu0.10Mg0.40Zn0.50Fe2O4/Ca2Ni5 nanocomposites a promising candidate as LIB anode.

Transition metal oxides containing different metal cations, also called as mixed metal oxides (MMOs), have confirmed improved electrochemical activities in comparison with single metal oxides (SMOs, containing single metal cations). In this study, for the first time, we have synthesized the hollow (Co0.62Fe1.38)FeO4/NiCo2O4 nanoboxes by simple and cost effective chemical precipitation method and investigated its lithium storage property. The uniqueness of this composite material is the hollow nano-structure with a very thin porous shell, which has rarely reported previously. The observed surface area of nanoboxes is 21.8 m2 g−1 with average pore size of 4 nm. As a results, the (Co0.62Fe1.38)FeO4/NiCo2O4 nanoboxes manifests a high reversible capacity of around 835.5 and 676.2 mAh g−1 over 350 cycles at a current densities of 200 and 500 mA g−1, respectively. The nano-dimention with hollow structure not only benefited electron and Li-ion transportation, it also provided large electrode–electrolyte contact area. Furthermore, the high reversible capacity in (Co0.62Fe1.38)FeO4/NiCo2O4 nanoboxes electrodes is most likely attributed to the synergistic electrochemical activity of both the phases, (Co0.62Fe1.38)FeO4 and NiCo2O4. Hence, based on high reversible capacity as well as an outstanding rate performance, the (Co0.62Fe1.38)FeO4/NiCo2O4 nanoboxes electrode sheds light on commercial applications as an alternative lithium-ion battery anode material.

In the present work, the effect of carbon nanotubes (CNTs) addition on the electrical conductivity and mechanical properties of thermoplastic polymers was investigated. CNTs were incorporated into the polymer matrix either in high concentrations (masterbatch) or as an additive in small quantity (dilution source of masterbatches in a polymeric binder). Masterbatches containing a 5–20% by weight of CNTs and composites obtained through their addition in polypropylene - the actual content of CNTs in polymer 0.1 and 0.01 wt% - were synthesized and characterized by mechanical tests and scanning electron microscopy. Also, the frequency dependence of the AC electrical conductivity of masterbatches and dilute composites were measured. It has been shown that the introduction of masterbatches containing 10 wt% of CNT provides a more efficient reinforcement of the composite than those using masterbatches with 5 and 20 wt% of CNTs. It is also found that the alternating current (AC) conductivities display two or three regions: regions of constant conductivity and regions where the conductivity increases with increasing frequency (following the percolation scaling law). It was also observed that the conductivity increases drastically with increasing CNT content in the investigated concentration range (from 0 to 20 wt%).

Products made of polypropylene (PP) are subject to photodegradation under UV-radiation leading to a change in the physical characteristics of the polymer. The addition of UV-filters, like ZnO nanoparticles, contribute to absorb UV-radiation and protect the polymer matrix. In this study ZnO nanopowder with a particle size of 50 nm was modified by 3-aminopropyltriethoxysilane (APTES) and introduced into the PP matrix. The optimal concentration of nanoparticles was determined. PP-films with a thickness of 100 and 200 μm were obtained. Structural and mechanical characteristics before and after irradiation by UV-radiation were studied by means of FTIR-spectroscopy, XRD, DSC, UV-VIS spectrophotometry and tensile tests. It was observed that UV irradiation of PP leads to the break of molecular chains, therefore releasing more molecular segments released. These segments can move and form a new crystal structure in the initial amorphous phase. The oxidation index of PP increased due to the formation of ketones. ZnO nanoparticles modified by APTES acted as nucleation sites and γ-phase was formed in the polymer. Also, the addition of ZnO-APTES nanoparticles in the polymer promoted absorption of UV-radiation in the wavelength range of 200–400 nm, thus protecting the polymer from degradation.

The results of experimental study of heat transfer and crisis phenomena at pool boiling of liquid nitrogen with different heating conditions on the surface with capillary-porous coating are presented. Porous coatings with different thicknesses (400 and 1390 μm), morphology and high porosity (up to 80%) were obtained using the new plasma spraying technique. It was shown that at steady-state heat release the heat transfer at boiling essentially depends on the thickness and morphology of the coating. The maximum enhancement (∼300%) compared to the smooth heater was detected to coated heater with a thickness of 1390 μm at low heat fluxes. The mechanism of heat transfer enhancement at pool boiling by using the capillary-porous coatings was proposed. Heat transfer hysteresis was detected for the heater with the coating of 400 μm. For the smooth heaters and the heater with 1390 μm coating, the heat transfer coefficients almost coincide with an increase in the heat flux and with its decrease. Data on the effect of coatings with different thicknesses on the critical heat flux (CHF) at boiling under steady-state heat release are presented. It is shown that for the smooth heaters the value of critical heat flux at rapid heating decreases in comparison with steady-state heat release. Capillary-porous coatings have a significant influence on development of the transition process and crisis phenomena at stepwise heat release. There is degeneration of boiling crisis development at rapid heating on the coated surfaces at the heat fluxes below the value of the CHF at steady state heat release. Fast transition to film boiling at stepwise heat release on the coated heaters with different thicknesses is observed at the heat fluxes 2 times higher than the critical heat fluxes, obtained at steady state heating.

Nowadays, the demands for the nanoparticles are increasing due to their tremendous applications in various fields. As a consequence, the discharge of nanoparticles into the atmosphere and environment is also increasing, posing a health threat and environmental damage in terms of pollution. Thus, an extensive research is essential to evaluate the discharge of these nanoparticles into the environment. Keeping this in mind, the present investigation aimed to analyze the discharge of aerosol nanoparticles that are synthesized in the laboratory via chemical precipitation and spray pyrolysis methods. The results indicated that the chemical precipitation method discharges a higher concentration of nanoparticles in the work site when compared to the spray pyrolysis method. The aerosol concentration also varied with the different steps involved during the synthesis of nanoparticles. The average particle's concentration in air for chemical precipitation and spray pyrolysis methods was around 1,037,476 and 883,421particles/cm3. In addition, the average total discharge of nanoparticles in the entire laboratory was also examined. A significant variation in the concentration of nanoparticles was noticed, during the processing of materials and the concentration of particles (14-723nm) exceeding the daily allowed concentration to about 70-170 times was observed over a period of 6 months. Thus, the results of the present study will be very useful in developing safety measures and would help in organizing the rules for people working in nanotechnology laboratories to minimize the hazardous effects.

Mussel shell, a calcium-rich resource, is found plenty in nature. We have developed a novel and facile method to convert mussel shell bio-waste into hydroxyapatite (HAp) biomaterial using microwave irradiation with the aid of ethylenediaminetetraacetic acid (EDTA) as chelating agent. The obtained HAp had flower-like morphology which can be a potential candidate for developing biomaterial for orthopedic applications. Moreover, the developed method has the potential to recover the bio-waste and reduce environment pollution.

Nanostructured cobalt microspheres were synthesized by a two-stage method. First, cobalt oxide Co 3 O 4 nanostructured microspheres were synthesized by spray pyrolysis at 700, 800, 900, 1000, and 1100, °C. Second, the nanostructured powders thus obtained were reduced to metal cobalt in a hydrogen atmosphere at 300 °C. For a sample obtained at 1000 °C, the influence of the reduction temperatures (220, 240, 270, 300, and 350 °C) on the metal cobalt powders properties was investigated. All the samples obtained were characterized by means of X-ray diffraction (XRD), coherent length determination and scanning electron microscopy (SEM). In addition, an average size of the particles , a specific surface area, and an effective diameter were determined. Finally, the magnetic properties of the metal cobalt, such as coercive force, saturation, and residual magnetization were measured by vibration sample magnetometer (VSM). The dependence on synthesis conditions of nanostructured metal cobalt microspheres properties was highlighted.

Magnesium nanoparticles (MgNPs) and silver nanoparticles (AgNPs) were synthesized by green synthesis method using Hydrangea paniculata flower extract. The occurrence of various organic molecules like terpenoids, steroids, saponins, alkaloids, quinone, glycosides and flavonoids in the flower was revealed by phytochemical and gas chromatography–mass spectrometry analyses. The formation of brown and black colloids, confirmed the presence of MgNPs and AgNPs, which was further supported by ultraviolet-visible absorbance at 360 and 450 nm by MgNPs and AgNPs. The X-ray diffraction analysis confirmed the cubic phase of MgNPs and AgNPs. FTIR analysis showed the presence of functional groups on the biosynthesized nanoparticles surface. The SEM and TEM analyses demonstrated the formation of spherical and ellipsoidal MgNPs and AgNPs. MgNPs was about 56–107 nm in size, whereas AgNPs was approximately 36–75 nm. In addition, both MgNPs and AgNPs showed excellent antioxidant potential and antibacterial activity against Escherichia coli and Staphylococcus aureus . The current green synthesis method using H . paniculata flower extract is a simple and an eco-friendly approach to synthesize MgNPs and AgNPs for making beneficial health care products.

This work represents the results of research on thermal stability, oxidation resistance at temperatures of up to 800 °C and electrochemical behaviour of (Ti,Al)N-(∼3 at.%)Cu and (Ti,Al)N-(∼8 at.%)Ni nanocrystalline coatings in acidic and alkaline media. The coatings were deposited by the arc-PVD method with a thickness of approximately 4 μm and crystallite size of less than 20 nm. It has been demonstrated that the composition and properties of the coating structures do not change when the coatings are heated in 10 −4 Pa vacuum at temperatures of 600, 700 °C for 1.5 h. Heating up to 800 °C caused an increase of crystallite size and reduction microstrain in the crystal lattice of the ceramic phase. The process is accompanied by deterioration of the coating hardness from 48 to 52 to 33–36 GPa. The (Ti,Al)N-Cu and (Ti,Al)N-Ni metal-ceramic nanostructured coatings are characterized by heat resistance up to the temperatures of 700 and 800 °С respectively. The coatings under study have tendency for self-passivation and resistance to pitting corrosion.

Coating samples in the Ti-Al-Mo-N system were obtained by arc-PVD method at variable bias voltage Ub applied to the substrate, and the partial pressure of nitrogen P(N2) used as a reaction gas. The deposited coatings were characterized by a nanocrystalline structure with an average grain size of 30–40 nm and multilayered architecture with alternating layers of (Ti,Al)N nitride and Mo-containing phases with a thickness comparable to the grain size. Coatings of (Ti,Al)N-Mo-Mo2N and (Ti,Al)N-Mo2N compositions were obtained by changing deposition parameters. The obtained coatings had hardness of 40 GPa and the relative plastic deformation under microindentation up to 60%. (Ti,Al)N-Mo2N coatings demonstrated better physicomechanical characteristics, showing high resistance to crack formation and destruction through the plastic deformation mechanism without brittle fracturing, unlike (Ti,Al)N-Mo-Mo2N. The friction coefficient of the study coatings (against Al2O3 balls under dry condition using a pin-on-disc method) reached the values of 0.35 and 0.5 at 20 °C and 500 °C respectively, without noticeable wear within this temperature range. These tribological properties were achieved by forming MoO3 acting as a solid lubricant. At higher temperatures the deterioration in the tribological properties is due to the high rate of MoO3 sublimation from friction surfaces.

The paper deals with the mineral wool production waste (cupola dust - CD), presents CD characterization and aims to reuse CD in production of refractory concrete with calcium aluminate cement. The study of CD covers its chemical, phase and thermal analyses along with the morphological study and determination of particles size distribution. Zeta-potential, electrical conductivity and pH values of CD suspension are presented in the paper as well. Commercial microsilica additive in refractory concrete has been replaced with cupola dust. Compositions of refractory concrete have been prepared by incorporating 1%, 2% and 3% of CD. The bulk density, ultrasonic wave velocity, cold crushing strength and thermal shock resistance of the created refractory concrete have been determined. Based on experimental results, it has been found that cupola dust may be used for the production of refractory concrete. The environmental impact related to the CD reuse in refractory concrete production has been evaluated as well.

Ternary Ni–Mo–N systems with high (up to 82 wt. %) content of Ni2Mo3N phase were produced by means of hydrogen reduction of different complex metal containing precursors. The precursors were obtained by two production routes, viz. evaporation and co-precipitation, with using of different initial Ni-containing salts. The samples were characterized by x-ray diffraction analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, low-temperature nitrogen adsorption, evolved gas analysis by mass-spectrometry. Catalytic activity of ternary Ni–Mo nitride catalysts for ammonia decomposition reaction at atmospheric pressure and different temperatures was determined. It was established that the composition of the precursor and its production route notably influenced the relative yield of the nitride phase and specific surface area of the products. The ammonia conversion vs. temperature plot was similar for nitride catalysts with onset at 400 °C and full conversion at 650 °C. It differed only at moderate temperatures in the range from 500 °C to 600 °C with the highest conversion rate for the sample obtained by evaporation route with using of nickel acetate as precursor. It was shown that the relative catalytic activity of all obtained nitride samples were substantially higher than the activity of iron containing catalyst used as the reference material.

Ceramic composites based on different mixtures of the powdered slags from silicomanganese manufacturing and synthetic potassium titanates, were produced and investigated. Green bodies were fabricated by uni-axial compression at 35 and 196 MPa. The sinters were obtained by one-stage (1100 °C/1 h) or two-stage (800 °C/1 h and 1100 °C/1 h) thermal regimes. The best mechanical properties were achieved for conditions of 33 wt% of slag, compressed under 196 MPa and treated by the two-stage regime of sintering. Structural investigation of the processes taking place in the produced ceramic materials was carried out by scanning electron microscopy and X-ray diffraction. The resulting products were characterized by a gradient phase composition constituted by perovskite, leucite, potassium hexatitanate, pyrophanite-ilmenite solid solutions, hollanadite-like and pyroxene-like crystalline phases as well as glassy phase of varied chemical composition. The mechanism of the sintering processes was also characterized.

Growing interest in nanoparticles' (NPs) behavior in the environment needs deeper purport of interactions between NPs and amino acids. In this work, we evaluated particle size distribution, aggregation degree, zeta potential, adsorption efficiency, and specific adsorption of three ZnO NPs with average sizes 30, 135, and 210 nm in 1 M glycine solution at different pH. The interaction of ZnO NPs and glycine is stimulated by the pH growth from 4 to 8 (an increase of glycine adsorption and decrease of particle aggregation), whereas at рН > 8 colloidal and adsorption properties are weakly affected by pH change. The addition of glycine to water promotes the aggregation of 30 nm NPs, while the aggregation of bigger NPs is weakened. For smaller particles aggregation and adsorption efficiency are higher, and specific adsorption is lower, meanwhile, the size effect is stronger in aggressive medium: alkaline – in water, and acid – in glycine.

Low-grade waste heat harvesting and conversion into electric energy is an important way of renewable energy development and thermo-electrochemical cells are promising devices to solve this problem. In this paper, we report original data on the current density and maximum output power dependents on voltage of the thermos-cells with nickel hollow microspheres electrodes and different electrolyte concentration (from 0.1 to 3.0 mol/l)which exhibit excellent hypothetical Seebeck coefficient and accordingly high open-circuit voltage values at low source temperature. The composition, microstructure and morphology of the hollow nickel microspheres based electrodes are included here. Because of the low cost of nickel based thermo-cells could be commercially feasible for harvesting low-quality thermal energy, in this connection, the raw data of measurements of their properties are given here. The data is related to "High Seebeck coefficient thermo-electrochemical cell using nickel hollow microspheres electrodes", Burmistrov et al., Renewable Energy, 2020 [1].