Performance of a silica-polyethyleneimine adsorbent for post-combustion CO2 capture on a 100 kg scale in a fluidized bed continuous unit

© 2020 Elsevier B.V. Polyethyleneimine (PEI)/silica adsorbents have been considered as a promising candidate for post-combustion CO2 capture, but the limited process study has been performed on a pilot-scale unit. Herein we report the 150 h continuous test results using a 100 kg sample of silica-PEI on a fluidized bed continuous unit. The CO2 removal efficiency and dynamic sorption capacity were evaluated continuously by changing a number of variables. For the sorption reactor, the changing variables were inlet H2O concentrations of 0–8.3 vol%, inlet CO2 concentrations of 12.0–21.5 vol%, bed temperatures of 50–70 °C and the bed differential pressures of 176–370 mmH2O. For the desorption reactor operated at the bed temperature of 129–130 °C, inlet H2O concentrations of 8.0–13.5 vol%, inlet CO2 concentrations of 14.6–81.2 vol% and bed differential pressures of 430–580 mmH2O were used. During continuous operation, CO2 removal efficiencies of over 90% were achieved with dynamic sorption capacities of 7.5 wt%. Solid sample collected during continuous operation were analyzed by TGA and 13C NMR to identity the decrease of CO2 adsorption capacity and the extent of thermo-oxidative side reactions. Slow oxidative degradation of the silica-PEI occurred because the transporting adsorbent was exposure to the non-humidified air in the solid transport system

Deformation-immunized optical deposition of graphene for ultrafast pulsed lasers

We demonstrate deformation-suppressed optical deposition of graphene onto an optical fiber by forming a graphene/polyvinyl acetate (PVAc) composite for ultrafast nonlinear photonics. With pure graphene, its nonlinear operation threshold is elevated by the optical deposition that cannot guarantee the intact two-dimensional nanoshape of graphene. The role of PVAc that provides immunity to graphene against deleterious degradation of morphology and optical nonlinearity is elucidated via electron microscope analysis, Raman characterization, and realizing passive mode-locking operation of fiber lasers. Resultant center wavelength, spectral width, and repetition rate of the laser pulses are 1572.6 nm, 0.6 nm, and 91.5 MHz, respectively

Energy-loss return gate via liquid dielectric polarization

One major energy loss in electronics is heat dissipation due to induced polarization in dielectric materials in the presence of electric fields. Kim et al. utilize large polarization in liquids to harvest dielectric loss via an energy-loss return gate design, which converts energy back to electricity

Versatile surface for solid–solid/liquid–solid triboelectric nanogenerator based on fluorocarbon liquid infused surfaces

The triboelectric nanogenerator (TENG) is a recent mechanical energy harvesting technology that has been attracting significant attention. Its working principle involves the combination of triboelectrification and electrostatic induction. The TENG can harvest electrical energy from both solid–solid and liquid–solid contact TENGs. Due to their physical difference, triboelectric materials in the solid–solid TENG need to have high mechanical properties and the surface of the liquid–solid contact TENG should repel water. Therefore, the surface of the TENG must be versatile for applications in both solid–solid and liquid–solid contact environments. In this work, we develop a solid–solid/liquid–solid convertible TENG that has a slippery liquid-infused porous surface (SLIPS) at the top of the electrode. The SLIPS consists of a HDFS coated hierarchical Al(OH)3 structure and fluorocarbon liquid. The convertible TENG developed in this study is capable of harvesting electricity from both solid–solid and liquid–solid contacts due to the high mechanical property of Al(OH)3 and the water-based liquid repelling nature of the SLIPS. When the contact occurs in freestanding mode, electrical output was generated through solid–solid/liquid–solid sliding motions. The convertible TENG can harvest electricity from both solid–solid and liquid–solid contacts; thus, it can be a unified solution for TENG surface fabrication

Highly transparent and water-repellent hierarchical-wrinkled-architecture triboelectric nanogenerator with ultrathin plasma-polymer-fluorocarbon film for artificial triboelectric skin

For scavenging energy from various places on the human body, multifunctional and comfortable triboelectric nanogenerators (TENG), that do not stimulate sensitive skin, are required. Therefore, it is essential to fabricate a TENG that is easy to deformation as well as biocompatible, ultrathin, and flexible. In this regard, we propose a hierarchical-wrinkled-architecture-TENG (HWA-TENG) with dual-wavelengths (microsize of 3.1 µm and nanosize of 311.8 nm). A plasma-polymer-fluorocarbon (PPFC) thin film was employed as a high-performance triboelectrification material, owing to its high surface charge potential, ultrathin thickness, transparency, and water repellency. The surface potential of the PPFC was extremely high at 7.28, which is comparable to that of bulk polytetrafluoroethylene. The surface area of HWA-TENG increased by as much as 3.5 % owing to the combination of the increased surface area effect of the HWA and high surface charge potential characteristics of the PPFC thin film, resulting in a high output performance of 200 V and 30 μA. The HWA-TENG can be successfully applied to triboelectric raindrops energy harvester and conformal artificial triboelectric skin. Owing to its eco-friendly, straightforward fabrication process, and high output performance, HWA-TENG can be used in several applications, including conformal TENGs for human body. © 2022 Elsevier LtdTRU

Unusual n-type thermoelectric properties of Bi2Te3 doped with divalent alkali earth metals

Bi2Te3-based materials are a representative thermoelectric system operating near ambient temperature. Their n-type family is very limited and underperforms the p-type counterpart, which is a major concern in the thermoelectric community. Here we report that alkali earth metals (AE = Mg, Ca, Sr, Ba) in Group 2 unusually induce n-type thermoelectric properties in Bi2Te3. Mg is the most efficient electron donor among them. The x = 0.01 sample of MgxBi2-xTe3 (x = 0.005, 0.01, 0.015) system exhibits remarkably enhanced power factor and ZT of ~0.8 at 350 K in comparison with pristine Bi2Te3. The improved performance is attributed to simultaneously enhanced electrical conductivity and reduced lattice thermal conductivity. Remarkably, MgxBi2-xTe3 materials show larger Seebeck coefficients than those expected by the theoretical Pisarenko relation. C. 2018 Elsevier Inc11sci

Data-Driven Enhancement of ZT in SnSe-Based Thermoelectric Systems

Doping and alloying are fundamental strategies to improve the thermoelectric performance of bare materials. However, identifying outstanding elements and compositions for the development of high-performance thermoelectric materials is challenging. In this study, we present a data-driven approach to improve the thermoelectric performance of SnSe compounds with various doping. Based on the newly generated experimental and computational dataset, we built highly accurate predictive models of thermoelectric properties of doped SnSe compounds. A well-designed feature vector consisting of the chemical properties of a single atom and the electronic structures of a solid plays a key role in achieving accurate predictions for unknown doping elements. Using the machine learning predictive models and calculated map of the solubility limit for each dopant, we rapidly screened high-dimensional material spaces of doped SnSe and evaluated their thermoelectric properties. This data-driven search provided overall strategies to optimize and improve the thermoelectric properties of doped SnSe compounds. In particular, we identified five dopant candidate elements (Ge, Pb, Y, Cd, and As) that provided a high ZT exceeding 2.0 and proposed a design principle for improving the ZT by Sn vacancies depending on the doping elements. Based on the search, we proposed yttrium as a new high-ZT dopant for SnSe with experimental confirmations. Our research is expected to lead to novel high-ZT thermoelectric material candidates and provide cutting-edge research strategies for materials design and extraction of design principles through data-driven research.11Nsciescopu

Coaxial cell printing of a human glomerular model: an in vitro glomerular filtration barrier and its pathophysiology

© 2023 IOP Publishing Ltd.Much effort has been expended in emulating the kidney’s glomerular unit because of its limitless potential in the field of drug screening and nephrotoxicity testing in clinics. Herein, we fabricate a functional bilayer glomerular microvessel-on-a-chip that recapitulates the specific arrangement of the glomerular endothelial cell, podocyte layers, and the intervening glomerular basement membrane (GBM) in a single step. Our perfusable chip allows for the co-culture of monolayer glomerular endothelium and podocyte epithelium, which display mature functional markers of glomerular cells, and their proper interactions produce GBM proteins, which are the major components of the GBM in vivo. Furthermore, we test the selective permeability capacity, a representative hallmark function of the glomerular filtration barrier. Lastly, we evaluate the response of our glomerular model to Adriamycin- and hyperglycemia-induced injury to evaluate its applicability for drug screening and glomerular disease modeling.11Nsciescopu

Effect of gasification biochar application on soil quality : trace metal behavior, microbial community, and soil dissolved organic matter

Compared to pyrolysis biochar (PBC), gasification biochar (GBC) differs in both composition and surface functionalities due to the use of an oxidizing purging gas. This work compares the effect of using PBC and GBC as soil amendments on the soil properties, trace metal bioavailability, soil microbial activity, and soil dissolved organic matter (DOM). Biochar-driven reduction of bioavailable metals does not necessarily result in a positive impact on the soil microbial growth. The DOM in the soil was strongly related to the soil microbial activity, as revealed by the strong correlation between the soil dehydrogenase activity (DHA) and soil dissolved organic carbon (r = 0.957, p < 0.01). Three identified fluorescent components (C1, C2, C3) in the soil DOM were closely associated with the soil microbial activity, for instance, with a clear positive correlation between the soil DHA and Cl (r = 0.718, p < 0.05) and a significant negative correlation between the total bacterial fatty acid methyl ester content and C3 (r = -0.768, p < 0.05). The bioavailability of Cd and Zn is not only related to the pH and surface functionalities of the biochar, but also to its aromatic carbon and inorganic mineral composition. This study further demonstrates that a fluorescence excitation-emission matrix coupled with parallel factor analysis is a useful tool to monitor changes in the soil quality after application of biochar, which is greatly relevant to the soil biota

Body-mediated bioelectronics for zero-powered ion release and electricals stimulation

Development of bioelectronics that can be used permanently in daily life without additional power sources is an important research goal. To this end, myriad permanent systems based on energy harvesting have been reported; however, there are still limitations, such as restrictions regarding specific installations and connections to lines. Herein, we present a new type of bioelectronics based on body-mediated energy transfer for zero-powered ion release and electrical stimulation. Body-mediated bioelectronics (BMB) is a new system that transfers electrical energy generated by various human activities (e.g., walking, using laptop) through the human body without energy loss. To apply the BMB to human skin, a biocompatible and skin-adhesive soft ion-diffusive hydrogel (IDH) was utilized as the bioelectrode. Finally, a BMB patch composed of IDHs with an iontophoretic structure was applied to the human body, and zero-powered electrical stimulation as well as active ion emission were implemented in daily life.</p