•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.
This work investigated carboxymethyl hydroxypropyl guar (CMHPG) as a potential base polymer for a fracturing fluid used in deep tight gas wells, synonym to high-temperature reservoirs. Fracturing is ...a common method to improve oil production by creating fractures in potentially productive reservoirs using fracturing fluids. Fracturing fluids are typically composed of water, sand, proppant, and many different additives to alter the capabilities of the fluid.A stable high-density fracturing fluid (HDFF) was developed to cope with scorching good temperatures up to 350F (177C)as well as to reduce the surface treating pressure. The HDFF consists of NaBr heavy brine, CMHPG, clay stabilizers, and zirconium and borate crosslinkers. A linear gel fluid was prepared by combining NaBr brine with CMHPG before adding the additives. The resulting fluid was then tested using a high-pressure, high-temperature (HPHT) rheometer.The results showed that the performance of the HDFF was optimum in an alkaline environment between pH 10 to 12. The efficiency of zirconium and borate crosslinkers were optimum at 0.7 ppm and 1.5 ppt, respectively. Concentrations higher than these values are not only uneconomical but will cause the fluid to be overly crosslinked, consequently reducing efficiency. In actual field operation, this is disastrous when the fluid does not flow to the fracturing column but instead swirls around the drill string as the drill string rotates. On the other hand, a reduction of concentration below the optimum values can cause fluid instability at high temperature reservoirs.The study was limited to using two different kinds of crosslinkers and various concentrations. Future studies can be conducted using other kinds of crosslinkers, as well as an investigation into the effects of varying temperatures, pressures, and pH on the HDFF using CMHPG.It can be concluded that HDFF using CMHPG as the base polymer can be a potential use in formulating fracturing fluids.Information on the rheological behaviour of HDFF using NaBr and CMHPG can provide a reference point for future scientists in developing a new formulation of fracturing fluid.
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.
The role of ice in the formation of chemically active halogens in the environment requires a full understanding because of its role in atmospheric chemistry, including controlling the regional ...atmospheric oxidizing capacity in specific situations. In particular, ice and snow are important for facilitating multiphase oxidative chemistry and as media upon which marine algae live. This paper reviews the nature of environmental ice substrates that participate in halogen chemistry, describes the reactions that occur on such substrates, presents the field evidence for ice-mediated halogen activation, summarizes our best understanding of ice-halogen activation mechanisms, and describes the current state of modeling these processes at different scales. Given the rapid pace of developments in the field, this paper largely addresses advances made in the past five years, with emphasis given to the polar boundary layer. The integrative nature of this field is highlighted in the presentation of work from the molecular to the regional scale, with a focus on understanding fundamental processes. This is essential for developing realistic parameterizations and descriptions of these processes for inclusion in larger scale models that are used to determine their regional and global impacts.
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.