Nano Phase Research Articles

Analysis of a novel nano phase change materials for thermal energy storage suitable in cold climates

Analysis of a novel nano phase change materials for thermal energy storage suitable in cold climates

Microbial Activity of TiO2 NPs via Two Phases Synthesized by The Sol-Gel Method

TiO2 titanium dioxide nano phases of anatase and rutile were controlled only by temperature control of the calcination process, which is a cheap technical technique, and were organized using a sol-gel process, which involved mixing titanium tetrachloride (TiCl4) with ethanol as starting materials, as well as heating at various temperatures (650, 850 ℃ ). The fundamental properties of the as-prepared nanomaterials were investigated using Fourier transform infrared spectra (FTIR). The antibacterial activity of TiO2 was next investigated using two strains of E. coli, Staphylococcus aureus, and Streptococcus bacteria. The TiO2 structure has a dominating phase of 650 °C in addition to rutile at 850 °C, with an average volume of crystalline (D) of 21.9 nm for the anatase phase and 30.41 nm for the rutile phase. According to XRD data, the spherical shape of the rutile phase is clearly evident in the TEM of TiO2 NPs, the tetragonal shape is clearly seen in the anatase, and the calcination process had a major effect on the crystal size. According to FTIR analysis, the majority of peaks are seen between 400 and 700 cm-1 as a result of bending and oscillation lengthening. The studies demonstrated that TiO2, in both protease and rutile forms, is a highly efficient antibacterial that can be used as a self-cleaning exterior to exterior surfaces (windows) as well as in bio-penetration places like hospitals and medical clinics.

Cooling Performance of a Nano Phase Change Material Emulsions-Based Liquid Cooling Battery Thermal Management System for High-Capacity Square Lithium-Ion Batteries

This study investigated the application of nanophase change material emulsions (NPCMEs) for thermal management in high-capacity ternary lithium-ion batteries. We formulated an NPCME of n-octadecane (n-OD) and n-eicosane (n-E) with a mass fraction of 10%, whose phase change temperatures are 25.5 °C and 32.5 °C, respectively, with specific heat capacities 2.1 and 2.4 times greater than water. Experiments were conducted to evaluate the thermal control performance and latent heat utilization efficiency of these NPCMEs. The NPCMEs with an n-OD mass fraction of 10% (NPCME-n-OD), particularly reduced the battery pack’s maximum temperature and temperature difference to 41.6 °C and 3.72 °C under a 2 C discharge rate, lower than the water-cooled group by 1.3 °C and 0.3 °C. This suggests that nano emulsions with phase change temperatures close to ambient temperatures exhibit superior cooling performance. Increased flow rates from 50 mL/min to 75 mL/min significantly lowered temperatures, resulting in temperature reductions of 2.73 °C for the NPCME-n-OD group and 3.37 °C for the NPCME-n-E group. However, the latent heat utilization efficiency of the nano emulsions decreased, leading to increased system energy consumption. Also, it was found that the inlet temperature of the NPCMEs was very important for good thermal management. The right inlet temperatures make it easier to use phase change latent heat, while excessively high temperatures may make thermal management less effective.

Enhancing thermal energy storage efficiency at low temperatures with innovative macro-encapsulation of nano phase change material in cementitious composites

In this study, phase change material (PCM) was encapsulated in a novel aluminium-based macro-capsule and indirectly applied to cement-based mortar to address leakage issues and enhance thermal management. To further improve the thermal efficiency of the PCM, nanofluid technology was utilized by incorporating multi-walled carbon nanotubes (MWCNTs). Thermophysical property tests were conducted to evaluate the thermal properties and stability of the PCM/MWCNT composite. Additionally, thermal cycling tests of the cementitious composites with macro-encapsulated nano-PCM were performed to verify their thermal performance for thermal energy storage under varying ambient temperatures. The results confirmed that the thermal conductivity of the nano-PCM was more than 100 % greater than that of raw PCM. Furthermore, the high-efficiency thermal energy storage cementitious composite was able to maintain the temperature above 0°C when the ambient temperature was −5°C, demonstrating its superior thermal energy storage performance. This innovative approach highlights the potential of the PCM/MWCNT composite for effective thermal regulation in subzero climates, providing a robust solution for enhancing energy efficiency in challenging environmental conditions.

Improving plasticity by Si-addition-induced coherent nanoprecipitates in Cu–Al–Mn alloy fabricated by laser powder bed fusion

In this paper, the Cu-10.8Al-8.3Mn-0.37Si alloy containing Mn5Si3 phase was obtained by adding Si element to the Cu-10.8Al-8.3Mn alloy. The two alloys were printed by laser powder bed fusion. The changes in the organization and tensile properties of the alloys and the mechanism were investigated. After Si addition, the Mn5Si3 nano phase precipitated in the alloy in addition to the β1 austenite phase. The Mn5Si3 phase was co-lattice with the β1 phase with an average size of 10 nm and was diffusely distributed. Standard tensile experiments showed that the yield strength of the Cu-10.8Al-8.3Mn-0.37Si alloy decreased by 57.7% and the elongation increased by 266% compared to the Cu-10.8Al-8.3Mn alloy, while the tensile strength remained essentially unchanged. The presence of Mn5Si3 phase provided nucleation points for martensite and promoted the generation of stress-induced martensite. Hence the yield strength was reduced. TEM results showed that the β1 phase in the Cu-10.8Al-8.3Mn-0.37Si alloy was fully transformed into stress-induced martensite after deformation, which displayed the transformation induced plasticity effect and hindered the slip of dislocations. Meanwhile, the Mn5Si3 phase was sheared by the stacking faults, which promoted the accumulation of hetero-deformation-induced stress. Therefore, the hardening capacity and plasticity of the Cu-10.8Al-8.3Mn-0.37Si alloy were enhanced. This work provides a new idea for the plasticity enhancement of Cu–Al–Mn-based shape memory alloys achieved by co-lattice nano-precipitated phase strengthening.

Development of highly stable low supercooling paraffin nano phase change emulsions for thermal management systems

Current research on thermal management systems focuses on aspects such as structural optimization of liquid cooling channels, with less research on the development of cooling media. Phase change emulsions, as latent heat functional fluids with significant potential, enhance heat transfer efficiency and temperature control in thermal management systems. However, the issues of significant supercooling and poor stability have hindered the further development of phase change emulsions. In this study, a highly stable, low-supercooling paraffin nano emulsion was successfully prepared by ultrasonication using SDBS, Span80, and Tween80 as composite surfactants and titanium dioxide nanoparticles as nucleating agents. It was found that the emulsion maintained excellent stability for 180 days of static stability and 200 thermal cycles without significant stratification. Subsequently, thermophysical property tests showed that the emulsion had a latent heat of phase transition of 45.48 J·g−1, and maintained good electrical insulating properties. The successful dispersion of 0.9 wt% titanium dioxide nanoparticles in the presence of SDBS resulted in a 77 % reduction in supercooling and a 20.5 % increase in thermal conductivity. Meanwhile, no instability was observed in the emulsion over 90 days of static stability test and 200 thermal cycles. The titanium dioxide-modified paraffin nano emulsions are characterized by high energy storage density, low supercooling, excellent stability, high thermal conductivity, and good electrical insulating properties, which give them significant potential as a cooling medium in thermal management systems.

Thermal energy storage, heat transfer, and thermodynamic behaviors of nano phase change material in a concentric double tube unit with triple tree fins

The contribution of this study is the proposal of a synergistic composite enhancement strategy involving tree fins and nanomaterials to improve the low thermal performance of phase change material (lauric acid) in a typical double tube latent heat thermal energy storage unit. The effects of nanoparticle concentrations and tree fin branching angles on the fluid dynamics, melting time, heat transfer, energy storage, and entropy generation characteristics were investigated. By employing tree fins, the melting time was respectively reduced by up to 60.20% and 36.05% compared to the finless case and the rectangular fins, while the energy storage power was respectively boosted by up to 143.36% and 37.45%. The increase of nanoparticle concentration was beneficial for melting heat transfer, and the dendritic fins with a bottom angle of 90° and a top angle of 30° yielded the highest energy storage performance. The total entropy generation of the melting process was mainly governed by the thermal entropy generation, and it showed a decreasing trend with the increase of time. In contrast to the finless configuration, the incorporation of fins diminished the integrated entropy generation value. Similarly, an elevation in nanoparticle concentration also led to a reduction of the integrated entropy generation value.

Preparation of presulfided oil-soluble NiMo catalyst for slurry bed hydrocracking of vacuum residue

Here, a method is proposed for constructing presulfided oil-soluble NiMo catalysts using tetrathiomolybdate nickel ammonium as a precursor via a chelating ligand exchange strategy. Leveraging the close chemical bonding between Ni and Mo atoms, the NiMo catalyst can undergo in-situ self-sulfidation to generate active NiMoS sites and a composite structure of Ni3S2 and MoS2 nano phase in tight contact, thus exhibiting strong synergistic effects. The NiMo catalyst exhibited outstanding performance in hydrocracking of vacuum residue (VR) achieving a 64.7 wt% VR conversion while maintaining a coke yield of 0.51 wt%, as well as the excellent hydrogenation activity of polycyclic aromatic hydrocarbons. Combined with density functional theory calculations, it was further revealed that the presence of Ni reduces the energy barrier for H2 dissociation on MoS2, thereby enhancing the hydrogenation activity of the catalyst and its ability to suppress coke formation. This work validates the efficient bimetallic synergistic catalytic effect of presulfided oil-soluble NiMo catalysts in the slurry bed hydrocracking process.

Expression of Concern for article entitled “Simultaneous application of active and passive methods in cooling of a cylindrical lithium-ion battery by changing the size of the elliptical cavity filled with nano phase change materials”

Expression of Concern for article entitled “Simultaneous application of active and passive methods in cooling of a cylindrical lithium-ion battery by changing the size of the elliptical cavity filled with nano phase change materials”

Investigating Xiaochaihu Decoction's fever-relieving mechanism via network pharmacology, molecular docking, dynamics simulation, and experiments

Xiaochaihu Decoction（XCHD）is a classic prescription for the treatment of fever, but the mechanism is not clear. In this study, We elucidated the mechanism of action through network pharmacology and molecular docking. A rat fever model was established to verify the prediction results of network pharmacology. The analysis revealed that 120 intersection targets existed between XCHD and fever. The TP53, STAT3, RELA, MAPK1, AKT1, TNF and MAPK14 as potential core targets of XCHD in fever treatment. GO and KEGG pathway enrichment analyses indicated that XCHD may act through pathways such as the AGE-RAGE signaling pathway in diabetic complications, TNF signaling pathway, IL-17 signaling pathway. Molecular docking results demonstrated that quercetin, kaempferol, β-sitosterol, stigmasterol and baicalein exhibited strong binding activity to key targets. Animal experiments showed that XCHD significantly reduced body temperature and levels of IL-1β, IL-6, TNF-α, NO, PGE2, and cAMP in rats with fever. Importantly, no significant difference was observed between the XCHD self-emulsifying nano phase plus suspension phase and XCHD group. XCHD exerts its therapeutic effects on fever through a multi-ingredient, multi-target, and multi-pathway approach.

Improved solar still productivity using PCM and nano- PCM composites integerated energy storage

The study investigates the impact of Phase Change Material (PCM) and nano Phase Change Materials (NPCM) on solar still performance. PCM and a blend of NPCM are placed within 12 copper tubes submerged in 1 mm of water to enhance productivity. Thermal performance is assessed across four major scenarios with a fixed water level of 1 mm in the basin. These scenarios include the conventional still, equipped with 12 empty copper rods and 142 g of PCM in each tube, as well as stills with NPCM Samples 1 and 2. Sample 1 contains 0.75% nanoparticle concentration plus 142 g of PCM in the first 6 tubes, while Sample 2 features 2% nanoparticle concentration plus 142 g of PCM in the subsequent 6 tubes. Aluminum oxide (Al2O3) nanoparticles ranging in size from 20 to 30 nm are utilized, with paraffin wax (PW) serving as the latent heat storage (LHS) medium due to its 62 °C melting temperature. The experiments are conducted under the local weather conditions of Vaddeswaram, Vijayawada, India (Latitude-80.6480 °E, Longitude-16.5062 °N). A differential scanning calorimeter (DSC) is utilized to examine the thermal properties, including the melting point and latent heat fusion, of the NPCM compositions. Results demonstrate that the addition of nanoparticles enhances both the specific heat capacity and latent heat of fusion (LHF) in PCM through several mechanisms, including facilitating nucleation, improving energy absorption during phase change, and modifying crystallization behavior within the phase change material. Productivity and efficiency measurements reveal significant improvements: case 1 achieves 2.66 units of daily production and 46.23% efficiency, while cases 2, 3, and 4 yield 3.17, 3.58, and 4.27 units of daily production, respectively. Notably, the utilization of NPCM results in a 60.37% increase overall productivity and a 68.29% improvement in overall efficiency.

Expression of Concern for article entitled “Effect of nano phase change materials on the cooling process of a triangular lithium battery pack”

Expression of Concern for article entitled “Effect of nano phase change materials on the cooling process of a triangular lithium battery pack”

Formation of nanophase metallic iron through charge disproportionation of ferrous iron during micrometeoroid impact‐induced splash melting

AbstractCharge disproportionation of ferrous iron has been considered as one of the mechanisms for the formation of metallic iron on the lunar surface. However, the detailed mechanism of the disproportionation reaction on the Moon is yet to be elucidated. We provide direct evidence for the ferrous disproportionation reaction that produces nano phase metallic iron (npFe0) during a rapid cooling process after splash melting from a lunar sample returned by China's Chang'e‐5 mission. Space weathering processes have resulted in the formation of three distinct zones at the rim of a pyroxene fragment, as observed through transmission electron microscopy. These zones, made up of splashed melts, newly formed melts from the substrate, and the mineral, are distinguished as I, II, and III. Quantitative analyses of the iron valence state by electron energy loss spectroscopy show that disproportionation reactions occurred in zone II at a low temperature of <570°C during a rapid cooling process. The reaction led to the production of α‐structure npFe0 and Fe3+ reserve in the glass phase. The npFe0 produced by the disproportionation reaction has a larger grain size than those formed from solar wind irradiation, implying that micrometeoroid impacts mainly contribute to the darkening of visible and near‐infrared reflectance. These findings reveal a novel rim structure by repeated space weathering and a universal formation mechanism of npFe0 during micrometeoroid impacts, suggesting that the disproportionation reaction could be widespread on airless bodies with impact‐induced splash processes.

The Effect of Surfactant on the Stability of Inorganic Salt Hydrated Phase Change Material Containing Graphene Nanoplatelet: An Experimental Investigation

The use of nano phase change material (PCM) as a heat transfer agent has spread and expanded as its thermal conductivity is higher than the base PCM, so its use has been increased in PVT systems. In this study, inorganic salt hydrated PCM was used as a base material and Graphene nanoplatelet (GNP) as an additive to improve the thermal conductivity of the resulted nano-PCM and its stability was studied using Cetyl Trimethyl Ammonium Bromide (CTAB) surfactants. The main objective of the present study was to investigate the effect of surfactant on the stability of different GNP concentration in CaCl2.6H2O PCM. The nano-PCM has been prepared using two-step method. The stability of nano-PCM depends on the surfactant used to slow the sedimentation of nanoparticles in the base PCM. The sedimentation process significantly reduces the thermal conductivity of nano-PCM and thus reduces heat transfer. The study results indicated that the employment of surfactant significantly affected the stability of nanoparticles added in the base PCM. The stability test ascertained the effectiveness of the surfactant applied in phase change material. With successive addition of surfactant, the stability of GNP in PCM was further enhanced to +49.3 mV of Zeta potential value.

Effect of rectangular, triangular, and semi-circular hybrid nano phase change material chambers under permanent magnetic field on the stepped solar still efficiency: An experimental study

Water has been considered one of the most important human needs since the beginning of human existence. This experimental study investigates the impact of utilizing hybrid nanomaterials (Fe3O4 + Graphene oxide) in phase change material (NPCM) under consideration of magnetic field on the production of a uniquely designed stepped solar still. The major aim of this research is to compare three different geometric hybrid NPCM chambers’ performance on the daily production of the stepped solar still. So 4 cases of experiments have been set and performed, namely, stepped solar still 1. Without NPCM, 2. With rectangular hybrid NPCM chambers, 3. With triangular hybrid NPCM chambers, and 4. With semi-circular hybrid NPCM chambers. To add the hours of the distillation process after sunset, the hybrid NPCM was applied. Cases 2 to 4 were experimented with under the permanent magnetic field, too. The daily productivity of Case 1, Case 2, Case 3, and Case 4 without magnetic field were 900 ml/day, 1580 ml/day, 1663 ml/day, and 1730 ml/day, respectively. The outputs indicated that Case 4 had the best accomplishment among all experiment cases. Case 4 of the experiment under the magnetic field yielded the highest daily efficiency of 15.6 %, whereas Case 1 only achieved 7 %. The daily productivity of the stepped solar still with semi-circular NPCM chamber, triangular NPCM chamber, and rectangular NPCM chamber has been enhanced by 92 %, 85 %, and 75 % without magnetic field and 131 %, 113 %, and 100 % under permanent magnetic field, respectively.

Glass formation, crystallization behavior, nanoprecipitate phase, and magnetic properties of Mn-Fe-Si-B-EM (EM = Zr, Nb, V) alloys

In this paper, the as-quenched Mn55Fe15Si20B7EM3 (EM = Zr, Nb, V) amorphous ribbons were produced by the melt spinning technique. The crystallization behavior, nanoprecipitate phase evolution, and magnetic properties of the Mn-Fe-Si-B-EM (EM = Zr, Nb, V) amorphous alloys were investigated by X-ray diffraction (XRD), differential scanning calorimeter (DSC), and the quantum design dynacool-9 physical property measurement system (PPMS). The Mn55Fe15Si20B7EM3 (EM = Zr, Nb, V) amorphous alloys show two-stage crystallization behavior. In the first stage, the primary crystallization results in the formation of α-Mn + Mn6Si/Mn3Si precipitates, while in the second stage, the secondary crystallization leads to the formation of the Mn2B phase. The Mn55Fe15Si20B7Zr3 (FZ) amorphous sample shows a most significant two-stage phase transformation, which the onset temperature of the primary and that of the secondary crystallization are 625.7 °C and 681.2 °C, respectively. The FZ amorphous sample undergoes a magnetic phase transformation from the spin glass (SG) state to a paramagnetic (PM) state at approximately 28 K. As the temperature increases, the magnetic phase transition can be expressed as: SG → PM. The annealed FZ nanocrystalline sample with α-Mn + Mn6Si nano phases enters the ferromagnetic (FM) state at 27∼70 K after undergoing spin glass transformation, and the magnetic phase transition is: SG → FM → PM. The annealed Mn55Fe15Si20B7V3 nanocrystalline sample containing nano α-Mn and Mn3Si phases shows two Curie transitions at 57 K and 130 K, respectively. The magnetic phase transition behavior can be expressed as: SG → FMΙ → FMΙΙ → PM.

Phonon relaxation effect by regeneration of nano-inclusions in SiGe for ultralow thermal conductivity and enhanced thermoelectric performance

SiGe alloys exhibit high thermoelectric performance at mid to high temperatures, but their wide applications are hindered by intrinsically high thermal conductivity. Here, we report a new strategy for regenerating ultrafine nano phases of CrSi2 and SiO2 with an average grain size of approximate 130 nm by chemical reaction of Si and strong oxidizing CrO3 in a p-type SiGe matrix. Based on the Debye-Callaway calculation, the nano-sized second phase leads to a reduction in phonon relaxation time, thereby lowering the thermal conductivity to an ultralow value of 2.15 W m−1 K−1 at 873 K. The boundaries between the second phases (CrSi2) and the matrix (SiGe) establish potential barriers, allowing carrier filtering and phonon scattering, thus increasing the power factor. Eventually, the sample (CrO3)0.3-Si80Ge20B0.5 reaches a peak ZT of approximately 1.12 at 873 K, with an average ZT of approximately 0.62 from 323 K to 873 K, representing a 55.56% improvement compared with Si80Ge20B0.5. Our method provides a promising approach for enhancing the thermoelectric performance of SiGe.

Correlating the Photovoltaic Performance and Stability of the All-Small-Molecule Organic Solar Cells to Their Intermixed Phases Determined by Concentration-Dependent Ultraviolet-Visible Absorption Spectroscopy.

In addition to the donor-acceptor nano phases, the intermixed phase within the organic blends is crucial for the photovoltaic performance and stability of the bulk-heterojunction organic solar cells (OSCs). Here, the intermixed phase of a representative M-PhS:BTP-eC9 all-small-molecule organic solar cell was investigated by a concentration-dependent ultraviolet-visible (UV-vis) absorption spectroscopy method, where a shift of the absorption maximum wavelength was measured for the acceptor component with the increase of the acceptor concentration. The blend ratios of the acceptor to the donor in the intermixed phase, corresponding to the critical concentration for the formation of the acceptor nanophase (CAP), were determined to be 0.35, 0.20, and 0.15 for the as-cast, thermal annealing (TA), and the combined TA and solvent vapor annealing films. These results indicated that M-PhS and BTP-eC9 are kinetically well intermixed during spin coating, whereas TA and the following solvent annealing promote the crystallization of BTP-eC9 molecules out of the intermixed phase. The photovoltaic performance of the M-PhS:BTP-eC9 cells with different blend ratios was investigated. The formation of the BTP-eC9 nano phase in the blend film leads to stable VOC and fast increased JSC, which can be understood by the reduction of bimolecular charge recombination and the formation of electron transporting pathways within the photoactive layer. Similarly, the critical concentration for the formation of the donor phase was estimated to be 0.15 by measuring the stabilized VOC and increased JSC values of the cells with different donor blending ratios. More importantly, after a fast "burn-in" thermal degradation, the M-PhS:BTP-eC9 cell showed excellent thermal stability aging at 85 °C for over 1128 h, which is in good accordance with the unchanged intermixed phases measured by the UV-vis spectra of the annealed films. The current work demonstrates the feasibility of the spectroscopy method to investigate the intermixed phases for organic bulk-heterojunction solar cells and proves that all-small-molecule solar cells can be intrinsically very stable.

Numerical study of the melting rate enhancement of nano phase change material in a modified shell and tube heat exchanger

The current investigation employs numerical analysis using ANSYS Fluent software to explore the melting behaviour of phase change material (PCM) and nano-PCM in a semi-circular shell and tube heat exchanger, utilizing dual side heating for enhanced conduction and convection rates of heat transfer. The study incorporates aluminium oxide nanoparticles at volume concentrations of 2 %, 4 % and 6 % within paraffin wax and assessing their impact on melting and thermal energy storage rates. Notably, the 2 % nanoparticle volume concentration exhibits an enhanced storage rate as compared to higher concentrations. The increase in nanoparticle concentration from 0 % to 2 %, 2 % to 4 % and 4 % to 6 % results in percentage reduction in melting time of 21 %, 3.51 % and 2.8 % respectively. Semi-circular configuration shows significant improvement in the energy storage rate as compared to the circular triplex tube configuration. The maximum energy storage rate of PCM for the semi-circular and circular configurations is 1.15 kW and 1.04 kW respectively, marking a 9.56 % increase over the circular configuration. Moreover, the semi-circular and circular configurations using nano-PCM achieve a maximum energy storage rate of 1.19 kW and 1.14 kW, representing a 4.20 % increase over the circular configuration.

Cooling Effect on Nano Eutectoid Phase Formation of Hypereutectic Zn-Al Alloy

To understand the nano phase formation, cooling experiments of a hypereutectic Zn-Al alloy containing 6 wt% of Al are carried out under two different cooling rates of 0.04 and 10.00 °C/s. The applied cooling rates significantly influence the phase change behavior of the investigated alloy. The liquidus temperature (TN) for the nucleation of the primary phase decreases from 390.3 to 382.9 °C, and the undercooling increases from 0.7 to 8.1 °C, as the cooling rate rises from 0.04 to 10 °C/s. The eutectic and eutectoid temperatures decrease from 381.5, 277.7 to 375.6 and 267.6 °C, respectively, when the cooling rate increases from 0.04 to 10.00 °C/s. The SEM and EDS analyses reveal that the solidified alloy contains the primary γ-ZnAl phase, the eutectic β-Zn phase, and the eutectoid α-Al and eutectoid β-Zn phases. The fast phase change and transformation caused by rapid cooling results in the formation of nano eutectoid phases and fine microstructure.