Nano Phase Research Articles

Evaluation of photovoltaic panels using different nano phase change material and a concise comparison: An experimental study

The cooling techniques of photovoltaic (PV) panels captured special attention due to positive impact on PV panels efficiency as continuous elevation of temperature degraded its performance. A number of studies have suggested the better prospects of air, water and phase change material (PCM) for thermal management of PV modules. The present work studies three different nanoparticle-based nano-PCMs for acceleration in performance of PV panel in terms of temperature reduction and increment of electrical efficiency. The experimental methodology was tested in the outdoor conditions of Taxila, Pakistan during winter seasons by using different concentrations (0.25 wt% and 0.5 wt%) of multiwall carbon nanotubes nanoparticles, graphene nanoplatelets and magnesium oxide nanoparticles in phase change material (PT-58). The topmost performance of PV panel is found at 0.5 wt% nanomaterial concentration in graphene nanoplatelets/PT-58 nano-PCM. The experimental results indicate that maximum temperature reduction is observed to be 9.94 °C, 6.53 °C for PV/nano-PCM at 0.5 wt% of graphene nanoplatelets/PT-58 nano-PCM and 0.25 wt% of graphene nanoplatelets/PT-58 nano-PCM respectively while it was 5.01 °C for PV/PCM with highest observation in electrical efficiency of 12.10%, 11.97% and 11.74% respectively as compared to conventional PV panel. The maximum percentage increase of electrical power was 33.07% in case of GNPs/PT-58 nano-PCM at 0.5 wt% of nanomaterial in base PCM. The graphene nanoplatelets based nano-PCM exhibited best results in terms of temperature reduction as well as electrical efficiency and higher concentration of nanoparticles indicated good results compared to low concentration in nano-PCM.

Design and production of a novel encapsulated nano phase change materials to improve thermal efficiency of a quintuple renewable geothermal/hydro/biomass/solar/wind hybrid system

In this article, a novel hybrid renewable energy system (HRES) is designed, introduced, and constructed to supply power, heat, and pure water. The proposed HRES is comprised of ground source heat pump/microalgal culture pond to produce microalgae biomass, parabolic trough collector/Solar still desalination/Photovoltaic panels to supply heat/electricity/water required for encapsulation of n-Octadecane with polymer shell via miniemulsion polymerization and conversion of bio-oil into biodiesel, and wind turbine/Proton exchange membrane to produce hydrogen in the strategic region of the Persian Gulf, Bandar Abbas. In this system, hybrid Nanofluid is used to increase the efficiency of the solar collector system. Moreover, for the first time, a transesterified conversion reactor (TCR) enhanced with thermal energy storage (TES) powered by renewable energies is introduced to yield more biodiesel. The produced Biodiesel along with diesel fuel with a mixture of air and hydrogen combine to form the fuel of diesel-fueled generator. In order to achieve the highest performance and efficiency of the proposed system, each part of the system is optimized based on the most influencing parameters using experimental design techniques. According to the results, the produced nanocapsules with an Encapsulation production efficiency of 67.1% and an average latent heat of 163.1 kJ/kg had enough potential to be used as TES in the TCR system. As the implementation of TES in the designed TCR could increase the biodiesel production by 34.9%. Also, with a power generation of 2.48 kW, the proposed HRES emitted 12% less NOx than the pure diesel.

Investigating performance of solar photovoltaic using a nano phase change material

Solar PV panels are playing a pivotal role in green energy generation, since their diffusion in global renewable energy market is greatly increasing every day owing to their reduced cost. Their efficiency is less and wavering around 15% only. Further, an inherent problem with their performance is the deterioration of their efficiency with the change in surface temperature. This issue could be resolved suitably through the proper thermal administration of the PV panel during working hours. Predominantly, this current work is intended to address the aforementioned issue with the assist of a Nano Phase Change Material (NPCM) which was primed by properly disbanding 0.5% volume of TiO2 nanoparticles within paraffin base. Two solar PV panels with similar configuration were experimented in this work in such a way that one without any NPCM and another one with NPCM amalgamated behind the panel. The results revealed that the NPCM effectively administered and reduced the daily average surface temperature of the panel by 13 °C and further, the daily efficiency of the panel was enhanced by 2.1%.

Progresses and challenges in the structural and magnetic properties of double perovskite La2NiMnO6 with their applications in solar energy

Lead free and environment friendly, light absorbing material is in high demand for the photovoltaic perovskite solar cell devices. The double perovskite La2NiMnO6 have the centre of attention for this demand. The present review is focused to discuss briefly the progress and challenges in the structural and magnetic properties of La2NiMnO6 in bulk, nano and thin film phases. The structural changes of La2NiMnO6 are highly interesting and have the direct correlation with the magnetic properties. On the basis of these transformations in the structure, efforts have been made to discuss several scientific progresses into technical novelties. This short review article is critically dedicated on reviewing the progresses, openings, and upcoming challenges in perovskite solar cell devices.

Thermodynamic reassessment of the Ag–Cu phase diagram at nano-scale

The Ag–Cu phase diagram at nanoscale was reassessed by CALculation of PHAse Diagrams (CALPHAD) method, considering the surface effect on the chemical potential of pure substance and excess Gibbs free energy of mixtures. According to the reported thermodynamic properties of pure Ag and Cu nanoparticles (NPs), and the measured melting eutectic temperatures of Ag8Cu2, Ag7Cu3, Ag6Cu5 to Ag5Cu5 NPs, respectively, obtained in the previous works, self-consistent thermodynamic parameters including the size effect were obtained by thermodynamic optimization. Using the obtained thermodynamic parameters, four Ag–Cu nano phase diagrams were constructed, and thermodynamic properties were calculated. It was indicated that the calculated Ag–Cu nano phase diagrams agreed well with experimental data.

Charge disproportionation and nano phase separation in textit{R}mathrm{SrNiO}_{4}

We have successfully grown centimeter-sized layered textit{R}mathrm{SrNiO}_{4} single crystals under high oxygen pressures of 120–150 bar by the floating zone technique. This enabled us to perform neutron scattering experiments where we observe close to quarter-integer magnetic peaks below sim 77~mathrm{K} that are accompanied by steep upwards dispersing spin excitations. Within the high-frequency Ni–O bond stretching phonon dispersion, a softening at the propagation vector for a checkerboard modulation can be observed. We were able to simulate the magnetic excitation spectra using a model that includes two essential ingredients, namely checkerboard charge disproportionation and nano phase separation. The results thus suggest that charge disproportionation is preferred instead of a Jahn–Teller distortion even for this layered mathrm{Ni}^{3+} system.

Characterization of MWCNTs-polystyrene nanocomposite based strain sensor

The usage of nano phase materials for strain sensing applications has attracted attention due to their unique electromechanical properties. The nanocomposite as piezo-resistive films provides an alternative for the realization of strain sensors with high sensitivity than the conventional sensors based on metal and semiconductor strain gauges. In this work, polymer based nano-composite with carbon nanotubes as filler were developed. The multi-walled carbon nanotubes/polystyrene (MWCNTs/PS) nano-composite films were prepared with different wt.% of CNTs using solution mixing method. Field emission scanning electron microscopy technique was carried out to investigate the morphology and dispersion of CNTs in the nano-composite sample. Fourier transform infrared spectroscopy technique was employed to characterize the bonds present in the prepared nano-composite. The electrical response of the composite films was recorded in the form of current-voltage (I-V) characteristics using source meter. The electromechanical response of the nano-composite films with different wt.% of filler CNTs was recorded by applying uni-axial tensile load. The electromechanical responses were then analyzed to obtain gauge factor for the strain sensitivity. The highest gauge factor of 133 was recorded during tensile testing of the nano-composite with 3 wt.% of CNTs fillers.

Estimating the Impact of Nanophases on the Production of Green Cement with High Performance Properties.

Ordinary Portland cement (OPC) production is energy-intensive and significantly contributes to greenhouse gas emissions. One method to reduce the environmental impact of concrete production is the use of an alternative binder, calcium sulfoaluminate cement, which offers lower CO2 emissions and reduces energy consumption for cement production. This article describes the effect of adding nanophases, namely belite, calcium sulfoaluminate, calcium aluminum monosulfate (β-C2S, C4A3S, and C4AS, respectively) on OPC’s properties. These phases are made from nanosubstances such as nano-SiO2, calcium nitrate (Ca(NO3)2), and nano-aluminum hydroxide Al(OH)3 with gypsum (CaSO4·2H2O). The impact of β-C2S, C4A3S, and C4AS nanophases on the capabilities of cements was assessed by batch experimentations and IR, XRD, and DSC techniques. The results showed that the substituting of OPC by nano phases (either 10% C4A3S or 10% C4A3S and 10% β-C2S) reduced setting times, reduced the water/cement ratio and the free-lime contents, and increased the combined water contents as well as compressive strength of the cement pastes. The blends had high early and late compressive strength. The IR, XRD, and DSC analyses of the blends of 10% C4A3S or 10% C4A3S and 10% β-C2S cement displayed an increase in the hydrate products and the presence of monosulfate hydrate. The addition of 10% C4AS or 10% C4AS and 10% β-C2S to OPC reduced the setting times, decreased the W/C ratio, free lime, the bulk density, and increased the chemically-combined water and compressive strength. Overall, the results confirmed that the inclusion of the nanophases greatly enhanced the mechanical and durability properties of the OPCs.

Mini-channel cold plate with nano phase change material emulsion for Li-ion battery under high-rate discharge

This paper presents a 4 mm ultrathin mini-channel cooling system based on a nano phase change material emulsion (NPCME) for prismatic Li-ion batteries under high-rate discharge. The NPCME has a larger specific heat capacity than water and no subcooling. Experiments were conducted to compare the cooling performance of water versus NPCME. The results indicate that NPCME can obtain a better cooling effect than water if the inlet temperature is below and near the melting point. At the discharge of 9C, the temperature and temperature difference of the battery pack cooled by 10 wt% NPCME-OP44E were 46 °C and 3.5 °C, compared with 49.5 °C and 4.8 °C under water cooling. Beyond that, the NPCME was able to reach the same cooling performance as water using lower pumping power. The pumping power of the 10 wt% NPCME-OP44E cooling system was only 18.5% that of the water cooling system when the cooling target for the battery temperature difference was 3.5 °C. With regard to charge-discharge duties, the 10 wt% NPCME-OP44E cooling system could limit Tmax and ΔTmax to 45.5 °C and 4 °C throughout all four cycles.

Resistive switching characteristics of Co2FeSi and Mn with Al2O3 granular nanocomposites

Materials containing high amounts of grain boundaries and crystal defects are promising candidates for the applications in memristor devices due to their intrinsic low manipulation energy. Here, we present memristive characteristics of granular composite samples containing Co2FeSi and Mn (CFS + M) for the first time. The structure is composed of an Mn oxide phase detected by x-ray diffraction (XRD) patterns which will role as an active layer. The bipolar memristance effect is seen in all samples which can be attributed to a valence change mechanism (VCM). Also, the composition of the granular material with different amounts of Al2O3 nano phases increased the RHRS/RLRS ratio through the reduction of the OFF current. Optimally, the RHRS/RLRS ratio of 1117 and a low threshold voltage of 0.88 V is obtained. Results can be considered for the development of memristors based on granular materials.

Comparative Study of Tubular Solar Stills with Phase Change Material and Nano-Enhanced Phase Change Material

This study is intended to investigate and analyze the operational performances of the Conventional Tubular Solar Still (CTSS), Tubular Solar Still with Phase Change Material (TSS-PCM) and Tubular Solar Still with Nano Phase Change Material (TSS-NPCM). Paraffin wax and graphene plusparaffin wax were used in the CTSS to obtain the modified solar still models. The experimental study was carried out in the three stills to observe the operational parameters at a water depth of 1 cm. The experiment revealed that TSS-NPCM showed the best performance and the highest yield in comparison to other stills. The distillate yield from the CTSS, TSS-PCM and TSS-NPCM was noted to be 4.3, 6.0 and 7.9 kg, respectively, the daily energy efficiency of the stills was observed to be 31%, 46% and 59%, respectively, and the daily exergy efficiency of the stills was recorded to be 1.67%, 2.20% and 3.75%, respectively. As the performance of the TSS-NPCM was enhanced, the cost of freshwater yield obtained was also low in contrast to the other two types of stills.

Nanomineralogy of evaporative precipitation of efflorescent compounds from coal mine drainage

Efflorescent nanophases (NPs) are found as a transitory accumulation of potentially hazardous elements (PHEs), particularly in tropical climates. The central objective of this study was to investigate the distribution of PHEs with NPs through the evaporative formation structures (EFS) of enormously PHEs-rich coal-mine drainages (CMD). The EFS were studied in natural coal mine drainage for five months in order to determine their geochemical and ecological structures and to assess their position in the reduction of PHEs in nature. The largest coal-fired power plant in South America, located in south Brazil, is used as an example of such a problem. In this work, a novel methodology for the analysis of PHEs in CMD precipitates is proposed for this affected coal area. The analytical method, combining X-Ray Diffraction (XRD) and advanced electron microscopies, shows the importance of nanomineralogy in understanding different circumstances of coal contamination. Several ultrafine-nanoparticles (UNPs) were identified in the sampled soils and river sediments together with the PHEs. A decrease in PHEs was identified in association with UNPs. However, further investigations are required with regard to the mobility of PHEs in water, atmosphere, soils, and sediments. The EPS was thoroughly studied, acquiring suitable understanding with investigational facts for Ca and Fe-sulphates, pickeringite, and several amorphous phases.

Spalling sensitivity and mechanical response of an ecofriendly sawdust high strength concrete at elevated temperatures

An eco-friendly high strength concrete (HSC) was developed with integration of wood waste (0, 5, 10, and 15%) in replacement to weight content of fine aggregate. Wood waste (sawdust) potentially a thermally degradable fiber was incorporated to enhance the fire endurance of high strength concrete. Mechanical strength and durability parameters of controlled and modified samples were explored along with the degradation on exposure to elevated temperatures. The investigated formulations were subjected to a maximum temperature of 800 °C on 5 °C/min ramp and then tested in the ambient conditions for the residual properties. Results depicted significant retention in compressive strength of sawdust high strength concretes (SD-HSC) at elevated temperatures with limited spalling sensitivity. Visual assessment along with micro-forensic evidences illustrate that SD-HSC exhibits reduced thermal cracking in macro, micro and the nano phase, in comparison with HSC. The experimental trends obtained from material property tests were used to develop simplified mathematical relationships that are helpful in performing analytical fire resistant studies for HSC formulations bearing sawdust grains. Conclusively, sawdust has been effectively utilized to develop an ecofriendly and fire resistant structurally applicable high strength concrete.

Nano essential oils against the red palm weevil, Rhynchophorus ferrugineus Olivier (Coleoptera: Curculionidae)

AbstractThe red palm weevil, Rhynchophorus ferrugineus, is the biggest pest of various palm species. The aim of this study was to evaluate the impact of the essential oils of purslane, mustard and castor (bulk and nano) on R. ferrugineus and to evaluate the oviposition deterrent effect to prevent new infestations. Prepared concentrations of essential oils (bulk and nano) were tested for their impact on R. ferrugineus larvae, pupae and adults. The most effective oil was purslane oil (bulk and nano), followed by mustard and the least effective was castor. The percent mortality of larvae was 75.2, 45.3 and 17.9% (bulk phase) and 92.5, 84.4 and 65.5% (nano phase) in purslane, mustard and castor, respectively, when treated with the high concentration. The percent mortality of adults was 67.2, 40.0 and 15.6% (bulk phase) and 83.5, 72.9 and 60.0% (nano phase) in purslane, mustard and castor, respectively, when treated with the high concentration. The number of eggs laid decreased with increasing concentration of the tested oils. Purslane essential oil showed good impact on R. ferrugineus larvae and adults followed by mustard and castor oils as bulk and as nano.

Surface mechano-chemical case carburising treatment (SMCT) of Ni-Cr-Mo steel: a post-annealing and differential scanning calorimetric (DSC) analysis

ABSTRACT The Ni-Cr-Mo steel samples carburised by surface mechano-chemical case carburising treatment (SMCT) were subjected to post low temperature annealing to relieve excessive residual stress and to induce carbide formation of untransformed carbon in the subtract. Samples were DSC analysed before and after 30 and 60 minutes of SMC treatment to investigate and understand the stability of the nano grains and phase changes. From DSC analysis, it is found that the onset of body-centred cubic iron (α-Fe) into face-centred cubic iron (γ-Fe) transformed at a temperature of 732°C. However, samples subjected to SMCT showed a different behaviour especially at a temperature range of 100–450°C. i.e. an exothermic reaction in this regime.

A three-dimensional nanoscale study in selected coal mine drainage

Sediments from coal mine drainages (CMDs) contain large quantities of suspended pollutants (possibly numerous chemical substances) along with sulfates and hazardous elements (e.g., chromium, zinc, copper, lead) that irreversibly accumulate in the water. As this accumulation can continue for decades after discontinuation of coal extraction, it is necessary to employ multidisciplinary approaches to control the threat in such zones. The quantity of amorphous material in some CMDs was evaluated by X-ray powder diffraction (XRD) using the Rietveld-based SIROQUANT software package. Modern Dual Beam Focused Ion Beam (FIB), field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscope (H-TEM), and energy-dispersive X-ray spectrometer (EDS) were used to evaluate the occurrence and transformation of nanophases (NPs). FIB is used to determine the 3D distribution of different species (internal structure) within individual NPs, whereas EDS is used to observe NP features (e.g., shape, constituent, range, assembly, and form of polymerization). The mineralogy of the sediment from the Brazilian CMDs, including the proportions of quartz, clays, Al–Fe-oxides, and amorphous NPs, appears to be related to the nature of the mineral matter in the relevant coal cleaning rejects (CCRs). The sediments of CMDs from the Brazilian coal area derived at a lower-pH range have different amorphous compositions as compared to those derived at a higher pH range. These special amorphous compositions are shown to be related to several other sediment properties such as particle surface area. The information gleaned in this study will be useful for further geochemical evaluation of CMDs in other parts of the world.

Characterization of nanoparticles embedded phase change materials

Nowadays nano phase change materials (PCMs) are commonly preferred by engineers for researches and to use them for thermal storage materials. This is because these materials store and release a large amount of latent heat during the process of melting and freezing which means changing from one phase to another. Engineers can use this property of PCMs in many ways such as thermal energy storage where the heat or coolness can be stored from one process and can be used later or at different locations. Thermal conductive substance such as nanoparticles is added to the former to increase the thermal conductivity of PCM and these materials are known as nano-enhanced PCM. To study the properties of fabricated composites, some characterization tests have done including Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), differential scanning calorimetry (DSC) and thermal and electrical conductivity tests. In this paper we will discuss the ideal characteristics of nano-enhanced PCM, thermo-physical properties, applications along with the challenges and direction of this new material and hoped this review will explore and provide some applications and the fundamental properties of composite PCM with CNT/graphene. By this experiment, thermal conductivity of nano-enhanced PCM gets increased. This composite PCM shows the huge potential in thermal energy storage system.

Preparation and analysis of novel paraffin based stable nano fluid dispersed with carbon nano tubes as effective phase change material for free cooling applications

Free cooling concept will play very important part in the future particularly in buildings. Air conditioners usage which leads to global warming can be partly reduced by using the free cooling concept. The best storage medium for cooling and heating is phase change material. Phase change material can be used effectively due to its energy storage capacity during charging and discharging process. The only disadvantage with phase change material is its low thermal conductivity and many researchers have studied various techniques for heat transfer enhancement and hence to improve the thermal conductivity. The present work aims to prepare a novel nano phase change material consisting of phase change material (Paraffin RT21) dispersed with Multiwall Carbon Nanotube (MWCNT) and to study its thermal and rheological properties. The thermal properties like thermal conductivity and rheological properties like viscosity, shear rate, shear stress and density of the nano fluid for different concentrations of MWCNT were evaluated in presence of surfactant. The result explicates that the efficiency of the nano fluid with MWCNT nano particles are better than the Paraffin RT21. Also the present work will provide an input to design effective thermal energy storage system for free cooling application in buildings.

One Pot Synthesis and Spectral Analysis of Ag Doped Polyvinyl Pyrrolidone Encapsulated Zinc Oxide Nano Composites and its Antibacterial Efficacy

A facile wet chemical method is used for the preparation of the transition metal doped semiconducting materials. To prepare pure PVP encapsulated ZnO nano particles by taking 1g PVP which was dissolved in 50 ml of ethanol and the solution is stirred for 2 hours at room temperature. After the stirring process zinc nitrate of (0.5, 1.0, 1.5)g was added and to this solution add 0.1g of silver nitrate and stirr vigarously. The resultant product is kept aside for ten day, then dried under vacuuo and annealed.The synthesized nano material was preserved in an airtight container and it is subjected for various spectral investigation tools like X -Ray Diffraction analysis, High Resolution Scanning Electron microscope Analysis, Photoluminescence studies, Ultra Violet Absorption and Fourier Transform Infrared Spectroscopic studies. The XRD results reveal that the synthesized samples are in highly crystalline in state and also show that the sample does not contain any metal peak which shows that the synthesized samples are in highly pure phase. The HR SEM result shows that the materials are in Nano phase. The UV visible absorption spectroscopic study shows strong absorption peaks of ZnO around 295 nm and Ag doped ZnO around 280 nm which is caused by the band edge transition of the synthesized semiconductor. The FTIR studies are also shows characteristic peaks for PVP, ZnO, Ag doped ZnO nanocomposites. The ZnO nano material behaves as a potential antimicrobial agent but the silver doped ZnO shows a lesser activity while comparing with the standard drug (Streptomycin).

Structural, Morphological, Vibrational, Thermal and Optical Properties of ZnS Quantum Dots in the Polymer Matrix

Background: Nanotechnology is believed to be a future for new human generations. Among different emerging materials, the Nanocomposites (NCs) would be on front line. The aim of the current study is provide a way to synthesize the ZnS-polyacrylamide NCs with emphasis on the effect of aging on polymer due to its various physical properties. Objective: To prepare and study the properties of ZnS-Polymer NCs with drying time in polymer matrix. Methods: ZnS-polyacrylamide NCs samples were synthesized by adding aqueous suspension of ZnS Nanoparticles (NPs) in Sol of acrylamide: bisacrylamide copolymer. These samples were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR), UV-Vis, and Photoluminescence (PL) spectroscopy. Results: From XRD data analysis, nano phase and zinc blend structure of the material are confirmed. From SEM images, the pristine ZnS NPs show spherical morphology, and this texture is still preserved in the polymer composites. FT-IR confirms that there is a strong interaction between polymer chain and ZnS NPs. The TGA results indicate that the incorporation of the NPs impacts the thermal properties of the ZnS-polymer NCs and displays higher thermal stability than the pure polymer matrix. The optical data predicts the band gap and Quantum Confinement Effect (QCE) and reduction of ZnS NPs within the polymer matrix. These NCs show emission in blue region with decreases in intensity with drying time. Conclusion: ZnS NPs incorporated in polyacrylamide were prepared by copolymer technique. Structural analysis confirms zinc blend structure. The vibration spectra of composites samples predicts an interaction between different functional groups of polymer with the metal sulfide. These NCs show enhanced thermally stability. The observed optical band shows a red shift and quantum confinement effect. The size calculated by XRD and optical data shows good correlation with each other. The PL spectra of the NCs exhibits a broad blue emission with excitation (λex = 320 nm). The visible region emission could be originated from the radiative recombination, involving defect states within the ZnS nanocrystals energy band.