Materials Science for Energy Technologies最新文献

The effective thermal conductivity is the most useful characteristic property to distinguish between two or more insulation materials. It is always the same by using different boundary conditions or different representative elementary volume sizes. The objective of this paper is to set variational formulations of different types of boundary conditions Dirichelet boundary condition (EBC), Neumann boundary condition (NBC), Mixed boundary condition (MBC) and Periodic boundary condition (PBC). Then effective thermal conductivity are investigated by scale effect study of the representative elementary volume size of the different categories of Polyurethane foam, closed cell foam, open cell foam and mixed cell foam. The apparent conductivity remain the same for MBC, PBC and EBC in the case of closed and open unit cell foam. The effective thermal conductivity for the different categories of PU foam converge as the REVs sizes increase. A comparative study with numerical, analytical and experimental thermal conductivity is performed in order to validate the results. A hybrid model is proposed in order to overcome the computational cost of the investigation of the effective thermal conductivity of mixed cell foam.

The synthesis of materials on magnetic activated carbon is of concern, with a simple and environmentally friendly. The research used pecan shell (Aleurites moluccana) as a carbon source. The breakthrough made in this research is to make magnetic activated carbon electrodes in supercapacitors. Obtained on the XRD diffractograms show the graphite lattice, respectively. Also, a sharp, narrow peak is seen at 2θ = 26° in the carbon samples spectrum, showing a highly graphitized fraction. FESEM-EDX showed AC20/80 that the shape of the particles was like plates indicating that the particles had been formed. AC80/20 is the surface morphology in which particles with irregular shapes indicate that particles have been formed, where the shape of the particles is irregular. The composition between C and O is also balanced. AC80/20 has lower Co content than AC20/80, AC40/60, AC60/40, and AC50/50 and it appears that AC80/20 is better than the others. The magnitude of the coercivity states that AC20/80, AC80/20, AC40/60, AC60/40, and AC50/50 are strong magnets. The lower the value of the open circuit potential, it will show electrochemical stability. The Nyquist plots of magnetic activated carbon show a straight vertical indicating the process of charge transfer resistance at the low electrode. Obtained specific capacitance AC80/20 at 150F/g.

The growing global demand for fish has led to an increase in fish waste (FW) production, necessitating efficient waste management strategies. Pyrolysis is a promising way to convert fish waste into high-value products. To achieve optimal waste mass reduction and gain insights into the pyrolysis process, estimating kinetic parameters is essential. This study investigated the pyrolysis of FW, Sardinella fimbriata, a previously unexplored waste source, using a thermogravimetric analyser. The study determined an average activation energy value of 84–124 kJ/mol using model-free isoconversional methods including Flynn-Wall–Ozawa, Kissinger–Akahira–Sunose, and Starink, whereas pre-exponential factor values were predicted to be between 10² and 10¹¹ s⁻¹. Further analysis using Criado's reduced master-plot approach showed that the experimental curves for pyrolysis coincided with many different theoretical plots for reaction mechanisms, with a concentration on reaction-order models. The analysis of thermodynamic parameters showed positive values of enthalpy change and Gibbs energy change for S. fimbriata FW pyrolysis, suggesting that the process is endothermic and non-spontaneous, while negative values of entropy change were observed across all conversion degrees as a result of the breakdown of complex organic molecules into simpler compounds. This study provides insights into the feasibility of thermal processes and offers new guidance for FW waste management and resource recovery, expanding the understanding of pyrolysis kinetics and thermodynamics for fish waste treatment.

Carbon neutrality innovation technologies are a leading research topic in sustainable development. Among these, anaerobic digestion is considered as a better choice for biowaste utilization. However, large amounts of produced biogas slurry hamper the widespread application of anaerobic digestion. The hydrothermal process is regarded as favorable to treat biogas slurry. The effects of inorganic and organic matter in processed water from the hydrothermal-treated biogas slurry were investigated in our research. The changes in inorganic elements such as P, Ca, Mg, Cu, and Zn were detected at different reaction temperatures (90, 120, 150, 180, 210, and 240 ℃) and acid catalytic conditions (0.5, 1, 2, 3, 4, 4.5, and 5 mL 5 M HCl). The changes in organic matter were analyzed using three-dimensional excitation emission matrix fluorescence spectroscopy. With the increase in the hydrothermal reaction temperatures, the quantity of total and inorganic P and the concentration of Ca initially increased and then decreased, concentration of Mg remained constant, while the concentration of Zn and Cu showed a trend of initial decrease and then increase, and the macromolecular organic matter was hydrolyzed into small, soluble molecular organic matter. With the increase in HCl, the amount of released total and inorganic P and concentrations of Ca, Mg, Zn, and Cu increased, and the macromolecular organic matter was hydrolyzed into small molecular organic matter. The hydroponic testing indicated that the processed water has a positive effect on the growth of maize. These results provide critical findings on the reuse of biogas slurry, which is useful for biowaste management and improves carbon neutrality strategy.

During the past few years, researchers have devoted extensive efforts to improve organic solar cell (OSC) performance to reach interesting power conversion efficiencies (PCE) exceeding 10 %. Among heterojunctions OSCs (BHJ) types, Fullerene based small molecule acceptors (SMAs) have proved to be a favorable option in virtue of their high-power conversion efficiency (PCE), good electronic conductivity and superior charge segregation. Yet, they represent some serious limitations, such as low light absorption over 600 nm, solubility in organic solvents, and inefficient processing. Accordingly, the so-called non-fullerene acceptors (NFA) organic group was developed and showed excellent characteristics over fullerene acceptors with their easily tunable band gap, strong absorption in the visible region, low voltage loss, good morphological stability and simple fabrication techniques. In the present paper, a series of non-fullerene electron acceptors (C1–C4) were designed by modifying the reference material R. we have obtained new conjugated organic structures by adding more functional capped units. The quantum chemical study (DFT/TD-DFT) approach was used to perform theoretical calculations in order to characterize the effect of end group redistribution via the frontier molecular orbital (FMO), optical absorption, reorganization energy in accordance with R. Using PTB7-Th as an electron donor, open circuit voltage (Voc), photovoltaic properties and intermolecular charge transfer have been also calculated for all the conceived compounds. The findings revealed that all engineered materials (C1–C4) possess narrow band gap and great optical characteristics. In addition the proposed structures have displayed comparatively lower electron and hole reorganization energies, we have found that C1 represents the lowest electron and hole reorganization energies, respectively 0.048 eV and 0.028 eV, consequently the highest electron and hole mobility [1]. These interesting outcomes could prove proposed electron acceptors to be excellent candidates in the improvement of optoelectronic properties of organic solar cell technology.

The present work aims to investigate the impact of tetrahydrofuran as a co-solvent on biodiesel production from rubber seeds to accelerate the transesterification reaction with a high biodiesel yield. We extracted the oil from rubber seeds before being reacted with methanol to synthesize biodiesel. It reveals that the composition of rubber seed oil was palmitic acid of 9.71 %, stearic acid of 13.09 %, oleic acid of 19.23 %, linoleic acid of 37.49 %, and linolenic acid of 20.47 %. The esterification process was examined to diminish the FFA content from 5.00 % to 1.99 %. The transesterification process was then examined to convert the triglycerides of rubber seed oil into biodiesel. The process variables in the transesterification were defined by Box Behnken Design, and the optimum condition was evaluated by response surface methodology. We found that the optimum condition was at temperature of 52 °C, reaction time of 30 min, and mass ratio of tetrahydrofuran to methanol of 1.4:1 to achieve a biodiesel yield of 97 %. The result suggests that the addition of tetrahydrofuran as a co-solvent accelerated the transesterification reaction of rubber seed oil with an excellent biodiesel yield.

One of the earliest manufactured and most frequently used resins is phenol formaldehyde (PF) resin. Even with lesser loadings, their characteristics can be enhanced by the addition of nano-ZnO. The novel PF/ZnO Nanocomposites synthesis by ultrasonic process. The optical properties of materials modified with wide-band gap semiconductor described via UV–vis spectroscopy. Diffuse reflectance spectroscopy (DRS) one of the possible tool to measure the reflected light from powders and rough surfaces clearly. Spectra obtained by DRS treated with Kubelka-Munk function in order to describe the energy band gap accurately for modified and pure para hydroxy benzoic acid polymer. The band gap of para hydroxy benzoic acid is about 4.5 eV and in modified samples range from 3.4 to 3.3 eV; the lowest band gap value corresponds to the higher ZnO concentration (0.005gm). The surface morphology characterize by SEM and AFM m where obtain the effected nanostructure as increase on the surface morphology and the roughness which is increase according the aggregation occur. EDX mapping appearance increase the distribution and present of zinc nanostructured in modified polymer. It was discovered that this was because of the ZnO NPs' good dispersion in the polymer matrix and their robust interfacial interaction with the PF matrix.

Since a composite electrode made of carbon and transition metal oxides has much potential to be the best electrode type for a future energy storage system, the low-temperature solution growth method was used to make a carbon framework from sweet potato with NiCo₂O₄ nanoparticles attached to it. This method is easy, cheap, and can be used for large-scale commercial production. FTIR spectra a peak band of Ni-O and Co-O and the bending functional group at wave number 857 cm⁻¹. XRD shows the crystal planes (1 1 1), (2 2 0), (3 3 1), (2 2 2), (4 0 0), (4 2 2), (5 1 1), and (4 4 0) at 2θ = 18.97°, 31.97°, 37.51°, 38.10°, 44.55°, 55.51°, 58.65°, and 64.92°, which indicates the NiCo₂O₄. The typical broad peaks around 23.3° can be linked to (0 0 2) lattice planes of amorphous carbon. The average size of the grains in the NiCo₂O₄/C samples was found to be 21.5 ± 0.5 nm. VSM shows that NiCo₂O₄/C has strong magnet properties. Based on the CV curve formed, it can be seen that NiCo₂O₄/C-2.8 has a balanced cathodic and anodic curve and also a higher current density than the others. It shows that NiCo₂O₄/C-2.8 has a higher ability to move electrons. The addition of the number of variations in the carbon mixture in NiCo₂O₄ shows the specific capacitance. It shows that carbon can prevent the movement of electrons in NiCo₂O₄, causing a decrease in performance. The right amount of carbon can increase the electron transfer ability.