Archive

Advanced NanoMaterials and Technologies for Energy Sector – AdvNanoEnergy 2018; Vol 2; Issue 2

Currently, there is a new attention to find a safe and efficient method to store hydrogen due to difficulties associated with compressed and liquidated methods. One of these methods is a solid-state storage by both chemisorption and physisorption. In this work, microporous activated carbon was prepared from Iraqi charcoal via chemical activation with KOH. Structural analysis and surface morphology characterized by XRD and SEM. Hydrogen adsorption performed using a homebuilt lab scale solid state hydrogen storage vessel. The vessel filled with hydrogen by pressurized H2 gas, under different low gas pressure and flow rate. It was found that increasing hydrogen gas pressure, within the low range used in this work during filling, would increase the capacity of the activated carbon to store it. 2.582157 wt. % hydrogen storage into activated carbon was achieved under the cryogenic condition and 5 bars pressure gas. Also, it was found that the residual potassium compound in activated carbons had an impact on the hydrogen adsorption enhancement at low pressures, while surface area and pore volume were constant.

================================================

Advanced NanoMaterials and Technologies for Energy Sector – AdvNanoEnergy 2018; Vol 2; Issue 1


Poly methyl methacrylate (PMMA) and Polycarbonate (PC) are low cost polymer materials which can be easily transformed into desired shapes for various applications. However, they have poor mechanical, thermal and electrical properties which are required to be enhanced to widen their scope of applications specifically where along with high strength, rapid heat transfer is essential. Multi Walled Carbon nanotubes (MWCNTs) are excellent new materials having extraordinary mechanical and transport properties. In this paper, we report results of fabricating composites of varying compositions of MWCNTs with PMMA and PC and their thermal conductivity behaviour using simple transient heat flow methods. The samples in disk shapes of around 2 cm diameters and 0.2 cm thickness with MWCNT compositions varying up to 10wt% were fabricated. One end of the disk was exposed to a constant steam temperature while the temperature of the other end was measured for each sample after a time period of 10seconds. The rise in temperature for the specimens was correlated with thermal conductivity which was appropriately calibrated. We found that both PMMA and PC measured high thermal conductivity with increase in the composition of CNTs. The thermal conductivity of 10wt% MWCNT/PMMA composite increased by nearly two times in comparison to pure PMMA while thermal conductivity of 10wt% MWCNT/PC composite specimen increased by nearly four times in comparison to pure PC. This indicates that presence of MWCNTs in minor compositions can significantly affect thermal conductive properties of both PC and PMMA, thereby enabling them for rapid heat dissipating units.

 


In this paper, the analysis of the influence of nano-sized defects on the critical current phenomena in the multilayered HTc superconductors is presented. The formation of the pinning potential barrier, determining the superconducting transport current flow, current-voltage characteristics, shapes and critical current limitations are discussed. Various initial positions of pancake vortices in the respect to nano-defects edge, acting as the pinning centers are considered. Influence of this initial position on pinning potential barrier magnitude is regarded. The elasticity forces of the vortex lattice are included into this model. It is considered influence of nano-defects created at fast neutrons irradiation process, arising during the work of the modern nuclear accelerators with superconducting windings and HTc superconducting current leads. Also, defects in the form of micro-cracks created especially during winding of the superconducting coils are considered in this paper. The influence of microscopic defects on the current-voltage characteristics in static and dynamic cases is considered. Attention is devoted to dynamic case, in which interesting phenomenon – peak effect should appear. Influence of nano-defects on the perpendicular to layers Josephson’s currents is regarded. Presented effects influence the work of HTc superconducting cables. The short model of the constructed by author cryocable is presented and progress in this field is briefly reviewed.

 


Development of nanostructured coatings play a crucial role in surface engineering for energy harvesting applications. Thermal characterization methods are one of the most accessible tools to study, model and predict the process parameters required to control nanostructure development during thermal treatment of different novel multi-material coating systems. Differential scanning calorimetry (DSC) is often used as a standard method to put in evidence different thermal events associated with different processes occurring in the coating materials during nucleation and growth as well as at the substrate/coating interfaces. Thermal analysis of inorganic and hybrid coatings is an essential tool for the validation of the new developed coating processes, allowing to study the reaction chemistry associated with the elimination of solvent compounds, nucleation and crystallization form solution to obtain the desired nanostructures and properties. Once the chemistry of the coating process is established, thermal stability of the coating in the temperature range required for a specific application may be assessed to obtain the desired crystalline phases and avoiding any other subsequent processes producing decomposition, internal stress and delamination of the film. The present paper is a first attempt to show some examples on how thermal analysis methods may be used to assess the thermal behaviour of novel inorganic coatings for developing novel energy harvesting systems.

================================================

Advanced NanoMaterials and Technologies for Energy Sector – AdvNanoEnergy 2017; Vol 1; Issue 4


Development of the amorphous granules of metals is one of the perspective directions connected with a production of the new (including nanostructured) functionally unique materials. The methods and devices for production the spherical granules (particles) of metals of a given size, with a high cooling a rate by solidification, are presented. The cooling rate of the drops during their solidification has been achieved up to 10 000 oC/s in our experiments! Such fine structure metals are so-called amorphous metals. The granular technology in the material science is using amorphous particles of nearly the same size (the uniform properties) produced from liquid drops, cooled down with a high cooling rate so that to avoid development of the big crystals, which can decrease the quality of a metal dramatically. The granular technology is a contrast to the powder metallurgy, where cooling of particles of different size is going with a low cooling rate being. Therefore, granules of a small size are normally required, except some special applications other than the ones of the material science. Big spherical granules cannot be produced this way because the big liquid drops have non-spherical form. The capillary forces fall rapidly down by growing of a diameter of particles over 3mm or so.

 


Modern nuclear fuels exploit the unique features of nano-structures. With proper engineering of fuel micro-nano-structure, fission products can, in principle, be separated from the fuel in-situ, and further be separated by the transmutation products. Fuel entities which are about 10 to 30 microns in diameter can contain the fuel ions in the particles while allowing the fission fragments to escape into the surrounding matrix, by virtue of the difference in travel distance. The matrix is chemically engineered to form stable phases with the most common fission products so that these products do not diffuse back into the fuel particles. This nano-structure engineering of fuels can be done with virtually any existing fuel, including oxides or metals for both thermal and fast reactors. A variant of this idea is to use a flowing liquid that may be continually cleaned, in order to remove the fission products, leaving a fuel which is clean and long-lived, or which may be sealed inside the pellet cladding improving the fuel performances and its reprocessing technology. The applications are in Light Water reactors, Fast breeder Reactors and Traveling singular wave reactor, making possible the increase in their burnup, life-time, performances.

================================================

Advanced NanoMaterials and Technologies for Energy Sector – AdvNanoEnergy 2017; Vol 1; Issue 3


The purpose of this paper is to introduce the hydrogen redox electric power (HREG) and hydrogen generation systems (HRHG). The HREG offers considerable conceptual advantage such that it functions with zero energy input, zero matter input and zero emission without violating the laws of thermodynamics. Its application ranges from the large scale central-station power generation down to the small scale on-board power generation system for electric vehicles with infinite cruising range. This generator utilizes a combined energy cycle consisting of a fuel cell that produces power and an electrostatic-induction potential-superposed water electrolytic cell (ESI-PSE) for the synthesis of a pure stoichiometric H2/O2 fuel for the fuel cell. According to the calculations using the data of operational conditions for the commercial electrolyzers and fuel cells, more than 70% of the power delivered from the fuel cell can be extracted outside the cycle as net power output. Because of the simplicity, effectiveness, cleanliness and self-exciting, this novel generator may offer a potential route for its practical application to the electricity and hydrogen production systems of the future.

 


The nitrogen and fluorine co-doped carbon catalyst (C-Mela-PTFE) exhibits high performance for oxygen reduction. However, the mechanism is remained elusive. Here, we investigate the structure and oxygen chemisorption processes of C-Mela-PTFE by experimental and theoretical methods. The results show that the C-Mela-PTFE materials exhibit layered porous structure, which facilitates the diffusion of oxygen. Compare N-doped catalyst, the N and F co-doped can reduce the energy barrier (from 1.08 eV to 0.23 eV) in oxygen adsorption process. In addition, the oxygen chemisorption on C-Mela-PTFE is following the side-on adsorption model (Yeager model).

================================================

Advanced NanoMaterials and Technologies for Energy Sector – AdvNanoEnergy 2017; Vol 1; Issue 2


To investigate the influence of support material type on the performance of doped carbon catalysts, electrochemical catalysts of doped carbon were prepared by pyrolyzing polyaniline (PANI), using melamine, XC-72R and TiO2 as support material, respectively. For the oxygen reduction reaction (ORR), support material had a significant effect on the performance of catalysts due to their different morphologies, structures and active N content. Melamine, XC-72R and TiO2 led to graphene-like (Fe-PANI/C-Mela), disordered (Fe-PANI/C) and core-shell (Fe-PANI/C-TiO2) structure, respectively, and their ORR activities were in the sequence of Fe-PANI/C-Mela > Fe-PANI/C > Fe-PANI/C-TiO2, it was consistent with the order of BET surface area and active N content. It was demonstrated that the H2-air single cell with Fe-PANI/C-Mela as cathode catalyst, had a maximum power density of 290 mW cm−2 at cell temperature of 70oC. It was about 5 and 2.5 times that of Fe-PANI/C-TiO2 and Fe-PANI/C. It is suggested that melamine is an excellent support material of doped carbon catalysts. Melamine contains a lot of nitrogen, and in the high temperature it is decomposed; which lead to high surface. In this paper, the better ORR performance can be attributed to the more active N content, surface area and particular graphene-like structures, which plays significant roles in the catalytic activity. Different support materials, in the heat-treatment processes, will lead to different N group and active N contents, different microporosity and different surface areas, and result in different oxygen reduction reaction performance.

 


The effect of various promoters (Ca, Ce, Mg, Zr) on the performance of 3%Ni/-Al2O3 catalysts in dry reforming of methane was investigated in a quartz tubular reactor under the following conditions: 1:1 CO2/CH4 ratio, flow rate CO2/CH4/Ar = 15/15/3 ml/min, temperature 700oC and at atmospheric pressure. The support,-Al2O3 was prepared by hydrothermal crystallization of boehmite. Various formulations of the promoted Ni/-Al2O3 catalysts were synthesized by wet impregnation method followed by drying and calcination at 750oC. The fresh and spent catalysts were characterized by various techniques. The compositions of the reactor inlet and outlet gases were analysed by online gas chromatography. The carbon deposition on the spent catalysts was determined by CHNS analyser. It was observed that the doubly promoted catalyst with Ca-Ce gave the best performance with the least coke deposition. The highest CH4 and CO2 conversion were found to be 72% and 79% with 2.247% carbon deposition for 10 hours of stream on run with this catalyst. Triply promoted (Zr-Ca-Ce) catalyst gave better result than doubly promoted Ca-Ce catalyst in activity but not in stability as well as carbon deposition resistance. Rh addition in doubly promoted Ca-Ce catalyst was also investigated that increased the activity (CH4 conversion 82% and CO2 conversion 96%) and decreased the carbon deposition (1.93%). This is a new formulation of catalyst which has performed very well in DRM process.

 


Lithium niobate (LiNbO3) nano and micro structures are deposited using spin coating method on quartz substrate. The precursor solutions are prepared under different time of stirring (8, 24 and 48h). The precursors are deposited by spin coating at 3000 rpm for 30sec and 0.5 mol/L. The samples are analysed by X-ray diffraction. The results show that as mixing time increases, the XRD starts to become structurally more regular, and it is found that the best mixing time was 48 h. The effects of annealing temperature (400, 500 and 600°C) on the structural properties is studied, to reach the ideal conditions for the preparation of optical waveguides.

 


Commercially pure titanium (CP-Ti) TA2 samples were subjected to thermal oxidation (TO) treatment at a temperature range of 500℃~850℃ for 210min. The oxidizing kinetics was analyzed, and the TO treated specimens were characterized by scanning electron microscopy (SEM), X-ray diffractometer (XRD), microhardness tester and immersion test. The results showed that the TO kinetics curves at 600 – 800℃ followed parabolic rate law. And thermally oxidized samples exhibit rutile TiO2 on the surface, the intensity of the rutile TiO2 become stronger with the TO temperature. TO treatment can significantly improve the surface hardness and corrosion resistance; meanwhile, it was found that the sample thermally oxidized at 700℃ presented the optimal performance.

================================================

Advanced NanoMaterials and Technologies for Energy Sector – AdvNanoEnergy 2017; Vol 1; Issue 1

In the present study, the pure ZnO nanoparticles was prepared by sol–gel method using zinc acetate dehydrate (Zn (Ac) 2·2H2O), as precursor and doped with metal ions and nonmetal ions like Vanadium, Dysprosium and Sulfur ions. The obtained ZnO nanoparticles have been studied using X-ray diffraction (XRD), which indicates the presence of hexagonal Wurtzite structure for pure and single doped and tri-doped ZnO-NPs. The effect of different dopent on crystallite sizes and lattice strain of ZnO-NPs were studied by using Williamson-Hall (W-H) analysis and Size-Strain plot method. We also calculate crystallite sizes of doped and pure ZnO NPs with the help of Debye-Scherrer method. The three form of W-H plot i.e. UDM, USDM and UDEDM and SSP model were used to calculated parameters such as strain, stress and energy density more precisely for all the reflection peaks of XRD corresponding to Wurtzite hexagonal phase of ZnO lying in the range 2θ =15–80 degree.

 


This paper reports the preparation of N-doped TiO2 nanocrystals with an average of size ca. 9.8 nm synthesized by a controlled sol–gel reaction followed by calcinations at 400 0C. Triethylamine, triethanolamine, diisopropylamine were used to dope titania with nitrogen. By coupling structural (by X-ray diffraction, RAMAN spectra) and morphological (HRTEM, BET) characterizations with spectroscopic analyses (EPR and XPS), it was found that the nature of the nitrogen precursor affect photocatalytic behaviour of the synthesized nitrogen doped titania nanoparticles. The photocatalytic efficiency of a TiO2 photocatalyst depends not only on the electronic properties of the materials. The availability of active sites on the material surface also plays a major role in the ability of the photocatalytic material to degrade organic contaminants. Nitrogen precursor with large surface area possesses more surface hydroxyl groups and hence produces more photoactivity. The photocatalytic activity was tested using a UV irradiation source with regard to decomposition of the dye fluorescein. In the case of fluorescein degradation the disappearance of the green colour was measured directly by means of fluorosence spectrophotometer. All N-doped samples produced a better removal of the dye fluorescein than the undoped and commercial samples.

 


The article presents the mechanical grinding of building materials in various mills by nanopowder. During mechanical activation of composite binders, the cement minerals active molecules arise when molecular defects are destroying in the packaging areas and the intermolecular forces of metastable decompensating phase are destruct. The process is accompanied by a change in the kinetics of solidification of Portland cement. Mechanical processes in the mineral materials grinding, together with increase in their surface energy, cause increase in the Gibbs energy of the powders and, accordingly, their chemical activity, which also contributes to high adhesion strength when contacting binders with them. Thus, the mechanical activation measures allow better use of the filling components properties and adjust their properties. At relatively low costs, it is possible to provide impressive and, importantly, easily repeatable results in the production.

 


The dissociation of O2 and HO2 are important reactions that occur at the cathode of fuel cells and require catalysts to proceed. There is a need to replace the presently used platinum catalyst with less expensive materials. Recently a boron doped armchair graphene ribbon has been shown by cyclic voltammetry to be a potential catalyst to replace platinum. However, the reaction catalyzed was not identified. Density functional calculations are used to show the reaction catalyzed is likely dissociation of HO2. The modeling is also used to show that other boron doped carbon nanostructures such as zigzag carbon nanotubes could be potential catalysts. The calculation shows that none of the boron doped carbon nanostructures can catalyze the dissociation of O2.

 


Poynting vector is a key property of electromagnetic waves as an energy-flow vector. Poynting vector in spatially uniform dielectric media is well known in an analytic form. In general, Poynting vector can be decomposed into orbital and spin parts. One way of controlling the direction of Poynting vector is to impose external potential onto the media under consideration. We are here to derive analytic expression of Poynting vector in the presence of spatially inhomogeneous refractive index, which serves as such a potential. For realizing proper profiles of refractive index, thermos-optic effect is proposed and the resulting alteration in the expression for Poynting vector is discussed.

 


The optical quantum generation was experimentally observed by using silicon nanocrystalline film which was irradiated by second-harmonic of YAG:Nd3+ laser. Matrix Hamiltonian for a model of Si-Si-Si- bridge by small external field perturbation was proposed. The coherent solution for a system with master equations which described photo-assistant electron transport in one dimensional chain of coupled quantum wells with two energy levels was obtained. The decoherence of electronic processes of excitation and tunneling causes the destruction of laser generation. Such behavior of upper-level population by its rising up to saturation value can be explained strictly by decoherent conditions, the time of coherence decay were estimated, and the conditions by which the photoluminescence in polarized nanostructured silicon film was appeared are considered. There are coherent and decoherent modes in electron transport realizing optical quantum generation. Both of them are possible in nanostructured media that has its geometrical parameters which are comparable with Gauss laser beam pumped nanocrystals. Because, the strong local fields inside the stressed polarized nanocrystalline silicon film play a great role in tuning or detuning by variation of levels’ energetic positions and, therefore, result in optical photon emission.

 


In the expanding world of small scale energy harvesting, the ability to combine thermal and mechanical harvesting is growing ever more important. We have demonstrated the feasibility of using ZnO nanowires to harvest both mechanical and low-quality thermal energy in simple, scalable devices. These devices were fabricated on kapton films and used ZnO nanowires with the same growth direction to assure alignment of the piezoelectric potentials of all of the wires. Mechanical harvesting from these devices was demonstrated using a periodic application of force, modeling the motion of the human body. Tapping the device from the top of the device with a wood stick, for example yielded an Open Circuit Voltage (OCV) of 0.2 – 4 V, which is in an ideal range for device applications. To demonstrate thermal harvesting from low quality heat sources, a commercially available Nitinol (Ni-Ti alloy) foil was attached to the nanowire piezoelectric device to create a compound thermoelectric. When bent at room temperature and then heated to 50◦C, the Nitinol foil was restored to its original flat shape, which yielded an output voltage of nearly 1 V from the ZnO nanowire device.

 


Nuclear renaissance isn’t possible without the development of new nano-hetero-structured materials. A novel micro-hetero structure, entitled “cer-liq-mesh”, nuclear fuel that self-separates the fission products from nuclear fuel, makes fuel reprocessing easier, allowing near-perfect burnup by easy fast recladding, being prone to improve the nuclear fuel cycle. Fuel heating analysis led to development of new direct energy conversion nano-hetero structured meta-materials resembling a super-capacitor loading from nuclear particles’ energy and discharging as electricity, prone to remove 90% of the actual nuclear power plant hardware, increasing the energy conversion efficiency. Usage of ion beam recoil analysis is used to measure and prove the nano-grains’ and nano-clusters’ special properties, such as shape-enhanced impurity diffusion and self-repairing in cluster structured fractal materials. The nano-grain liquid interface is studied by ion beam simulation in order to develop a new generation of nuclear fuels with enhanced breeding and transmutation properties, able to directly separate the transmutation products, thus reducing the need for hard, hazardous chemical processes. Ion-beam channeling in material may be extended to neutrons and gamma rays, and using hybrid NEMS structures new applications may create novel solid-state nuclear reactor control reactivity system, radiation modulators for gamma, neutrino communication systems and ultra-light radiation shielding.