•An aerogel-based structure is proposed as an alternative to fin-based structures.•Adsorbent-impregnated aerogels enhance the performance of adsorption heat pumps.•Appropriate amount of impregnation ...in the structure is experimentally investigated.•Numerical analysis was conducted to understand the heat and mass transfer.•From sensitivity analysis, the porosity of the structure was found to be critical.
Efforts to address global warming and fossil fuel depletion have driven the development of environmentally friendly and efficient energy systems. Adsorption heat pumps, which use thermal energy, are becoming popular since they can use renewable energy sources such as solar, geothermal, and waste heat. To effectively deliver thermal energy to the adsorbent medium in the heat pump systems, two methods are often utilized: packing the adsorbent between the fins or coating the adsorbent on the fin surfaces. The packing type exhibits a higher refrigerant adsorption capacity than the coating type. However, the heat transfer ability is low in the former, and the adsorbent quantity is limited in the latter. Therefore, we developed aerogel-based structures as an alternative to fin structures—a breakthrough that offers improved heat transfer capabilities compared to packing, and it overcomes the quantity limitations of coating representing a significant advancement beyond the existing literature. As a result, our innovation presents a promising avenue for enhancing thermal energy delivery in heat pump systems. In our study, we impregnated sodium bromide (NaBr) adsorbent into graphene aerogel (GA). The GA-based structure achieved a significantly improved specific cooling power of adsorption (SCPads) of 3.043 kW/kg, compared to the conventional NaBr-packed finned flat plate structure with 0.065 kW/kg. We also conducted a numerical analysis to gain a deeper understanding of the experimental behavior. Additionally, we conducted a sensitivity analysis using the numerical model, revealing the pivotal role of adsorbent structure porosity in influencing SCPads. This research demonstrates the potential of using aerogels impregnated with adsorbent materials in adsorption reactors, leading to enhanced performance of heat pumps. The proposed adsorbent structure could be applied in future adsorption and desorption reactors.
The purpose of this study was to determine how the development of nabr al-ashwat al-arabiyyah material improved the Arabic speaking skills of Muhammadiyah 3 Yogyakarta Junior High School students. ...This research utilised a research and development method with the ADDIE model, namely analysis, design, development, implementation and evaluation. The data collection process employed observation, questionnaires, interviews and tests. The results explain that judging from the average pre-test value, it can be said that nabr material has proven effective in improving the speaking proficiency of the material Arabic lessons in grade IX of Muhammadiyah 3 Yogyakarta Junior High School students. The researcher concluded that the development of nabr material from the pre-test results obtained an average value (mean) of 60.27, the minimal value being 48, the maximum value being 70 and the standard deviation being 6.036. while in the post-test table the average student score (mean) is 82.77, the minimum value being 70.00, the maximum value being 98.00 and the standard deviation being 8.149, which was proven by the effectiveness test using the JASP application. The paired samples t-test showed an increase in self-regulation (t (36) = -21.761, p <.001). This data shows that the p-value is <0.05; hence, it can be concluded that the data is significant. Furthermore, the Cohen's d table shows an effect of -3.627.
All‐inorganic perovskite has attracted much attention because of the higher stability. Many organic additives such as alkyl chain ammonium and polymers are usually introduced into perovskite to ...improve their performance. However, the long chain ammonium cations in perovskite may restrain the carrier transfer ability and ultimately deteriorate the performance of light‐emitting diodes (LEDs). In this work, the CsPbBr3 nanoparticles (NPs) are in situ fabricated by the synergistic effect of poly(ethylene oxide) and phenethylammonium bromide (PEABr). Particularly, sodium bromide (NaBr) with better conductivity is successfully introduced into CsPbBr3 NPs to substitute PEA partially, ultimately to passivate the defect and promote the carrier transfer ability. Besides, the addition of NaBr results in a better promotion for electron mobility than for hole mobility leading to a more balanced charge transport in devices. It enables NaBr based CsPbBr3 NPs green LEDs to exhibit a maximum external quantum efficiency (EQEmax) of 17.4%, which presents obvious enhancement compared to the LEDs without NaBr (EQEmax = 12%). Further, NaBr based CsPbBr3 NPs LEDs with a large area of 108 mm2 still show a high maximum EQE of 10.2%. Above all, this work provides a feasible way of adding metal additive in perovskite films to improve the performance of perovskite LEDs.
A maximum external quantum efficiency of in situ fabricated CsPbBr3 Nanoparticles (NPs) light‐emitting diode is demonstrated to be 17.4% by introducing sodium bromide to CsPbBr3 NPs to passivate defect and promote the charge transfer ability.
Solid-state metal batteries with nonflammable solid-state electrolytes are regarded as the next generation of energy storage technology on account of their high safety and energy density. However, as ...for most solid electrolytes, low room temperature ionic conductivity and interfacial issues hinder their practical application. In this work, Na super ionic conductor (NASICON)-type Na3Zr2Si2PO12 (NZSP) electrolytes with improved ionic conductivity are synthesized by the NaBr-assisted sintering method. The effects of the NaBr sintering aid on the crystalline phase, microstructure, densification degree, and electrical performance as well as the electrochemical performances of the NZSP ceramic electrolyte are investigated in detail. Specifically, the NZSP-7%NaBr-1150 ceramic electrolyte has an ionic conductivity of 1.2 × 10–3 S cm–1 (at 25 °C) together with an activation energy of 0.28 eV. A low interfacial resistance of 35 Ω cm2 is achieved with the Na/NZSP-7%NaBr-1150 interface. Furthermore, the Na/NZSP-7%NaBr-1150/Na3V2(PO4)3 battery manifests excellent cycling stability with a capacity retention of 98% after 400 cycles at 1 C and 25 °C.
With great research potential, the perovskite solar cells (PSCs) have been well developed in recent years, but there are still some urgent issues like efficiency and hysteresis defects that severely ...limit their commercialization. Interface modification is a significant measure to reduce defects and promote performance. In the article, an easy and effective strategy of modifying the electron transport layer (ETL) with NaBr is proposed to improve efficiency and reduce hysteresis. The charge carrier dynamics can be greatly optimized by diffusing NaBr on the ETL. The efficiency of the NaBr coated device can achieve 21.16%, which is extremely higher than the control one and shows low hysteresis behavior with a hysteresis index reduced from 0.135 to 0.025. The results indicate that the NaBr modification provides a novel strategy for preparing PSCs with high efficiency and low hysteresis.
Perovskite solar cells based on the CsPbI 2 Br photoactive layer have received much attention recently because of the suitable bandgap and good thermal stability for CsPbI 2 Br, as compared with ...other perovskite photoactive materials. However, the poor quality for the normally prepared CsPbI 2 Br layers severely restricts realization of high performance for the related solar cells. Herein, we report a facile low-temperature solution process, in which NaBr is introduced into the CsPbI 2 Br precursor solution as an additive, to prepare high-quality CsPbI 2 Br layers with the improved crystallinity and reduced defect/trap density, as well as the reduced surface roughness and enhanced resistance to moisture and Ag diffusion. Thanks to the enhanced charge extraction, suppressed carrier recombination because of the improved CsPbI 2 Br quality, the power conversion efficiency (PCE) of the corresponding solar cells has a remarkably increase to 14.70% compared with 13.26% for the control device with the pristine CsPbI 2 Br layer. Moreover, the improved operation stability for the unencapsulated devices with the NaBr-modified CsPbI 2 Br layers is observed, i.e., ∼90.1% retention of the initial PCE after 200 h aging in air with the relative humidity of 30%-40%, much more stabler than the control device.
•Gas solubilities of CO2 in the DES (1 sodium bromide + 6 ethylene glycol) were measured.•Measurements were conducted at temperature range 293.2 to 323.2 K and pressures up to 37 bar.•The CPA and SRK ...EoSs were used to model the solubility data.
In this study, carbon dioxide solubilities were measured experimentally in the DES composed of 1 NaBr + 6 ethylene glycol at temperatures ranging from 293.2 to 323.2 K and pressures up to 37 bars. The minimum and maximum measured CO2 solubilities (in mole fraction) within the investigated temperature and pressure ranges were 0.0013 and 0.0526, respectively. The measured data were then used to optimize the values of fitting parameters of the Cubic Plus Association, and the Soave–Redlich–Kwong EoSs equations of state. The AARD% values of 3.37 % and 2.52 % for SRK and CPA EoSs, respectively, showed reliable results for both models. However, the SRK EoS could estimate accurate carbon dioxide solubilities only by much larger binary interaction parameters, as compared to the CPA EoS. Also, using the measured data, the values of Henry’s constant, standard enthalpy, standard entropy, and standard Gibbs free energy of dissolution were calculated according to thermodynamic relations. The stronger interactions in the mixture of carbon dioxide with DES by the establishment of new intermolecular bonds (as compared to the pure DES), leads to the liberating of energy upon dissolution. This also results in less disorder and chaos as indicated by analyzing the above-mentioned thermodynamic properties.
Carboxylated cellulose nanocrystals prepared by TEMPO-mediated oxidation exhibit a distinct ability to form nematic order, however, their ability to form chiral nematic films remains relatively ...unexplored. In this study, bleached cotton pulp hydrolyzed with hydrochloric acid and oxidized by TEMPO-mediated oxidation produce carboxylated cellulose nanocrystals with different aspect ratios 33.1, 32.8, 30.9, 29.0 and 28.9, and surface charge densities 0.16, 0.56, 1.00, 1.25, and 1.42 e·nm−2. By tuning the aspect ratio and surface charge density, the optimal carboxylated cellulose nanocrystals producing left-handed chiral nematic films by evaporation-induced self-assembly are obtained. The left-handed chiral nematic films enable selective reflection of left-handed circularly polarized light with the peak wavelength tunable from the visible to the near-infrared regime by modifying the characteristics of nanorods and suspensions. Such carboxylated cellulose nanocrystal films transform spontaneous luminescence to right-handed circularly polarized luminescence with the peak luminescence dissymmetry factor of −0.51.
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