Metal–organic frameworks (MOFs) are a class of hybrid porous crystalline materials comprising of metal centers coordinated to organic linkers. Owing to their well-defined pores and cavities in the ...scale of molecules combined with abundant surface chemistry, MOFs offer unprecedented opportunities for a wide range of applications including membrane-based gas separations. It is not straightforward (often requiring multiple steps) to prepare membranes of MOFs due to the fact that the heterogeneous nucleation and growth of MOF crystals on porous supports are not generally favored. Furthermore, the performance of polycrystalline MOF membranes strongly depends on the membrane microstructure, in particular, the grain boundary structure. Here we report a simple one step in situ method based on a counter-diffusion concept to prepare well-intergrown ZIF-8 membranes with significantly enhanced microstructure, resulting in exceptionally high separation performance toward propylene over propane.
Main conclusion
A new imaging platform was constructed to analyze drought-tolerant traits of rice. Rice was used to quantify drought phenotypes through image-based parameters and analyzing tools.
...Climate change has increased the frequency and severity of drought, which limits crop production worldwide. Developing new cultivars with increased drought tolerance and short breeding cycles is critical. However, achieving this goal requires phenotyping a large number of breeding populations in a short time and in an accurate manner. Novel cutting-edge technologies such as those based on remote sensors are being applied to solve this problem. In this study, new technologies were applied to obtain and analyze imaging data and establish efficient screening platforms for drought tolerance in rice using the drought-tolerant mutant
osphyb
. Red–Green–Blue images were used to predict plant area, color, and compactness. Near-infrared imaging was used to determine the water content of rice, infrared was used to assess plant temperature, and fluorescence was used to examine photosynthesis efficiency. DroughtSpotter technology was used to determine water use efficiency, plant water loss rate, and transpiration rate. The results indicate that these methods can detect the difference between tolerant and susceptible plants, suggesting their value as high-throughput phenotyping methods for short breeding cycles as well as for functional genetic studies of tolerance to drought stress.
A novel method for a beam pattern reconfigurable circularly polarized (CP) transmitarray antenna based on passive metasurface is proposed by a rearrangement of source antennas. Two source antennas ...among eight source antennas are selected for the fine beam steering. The beam steering angle can be finely controlled by the positions and phase difference of the source. Moreover, this kind of transmitarray antenna can be utilized to generate multibeam by the combination of the source antennas for radiation to different directions. To verify its feasibility, the planar CP source antenna is designed to operate at 5.8 GHz. Also, the metasurface consists of four layer separated by four substrates to cover full transmission phase variation of 2π, and the metallic layers are designed to circular patches. As a result, the steering angle is experimentally observed at each 0, +20, and +40°, and dual beam radiating to −30 and +30° also is measured.
The AP2/EREBP family transcription factors play important roles in a wide range of stress tolerance and hormone signaling. In this study, a heat-inducible rice ERF gene was isolated and functionally ...characterized. The OsERF115/AP2EREBP110 was categorized to Group-IIIc of the rice AP2/EREBP family and strongly induced by heat and drought treatment. The OsERF115/AP2EREBP110 protein targeted to nuclei and suppressed the ABA-induced transcriptional activation of Rab16A promoter in rice protoplasts. Overexpression of OsERF115/AP2EREBP110 enhanced thermotolerance of seeds and vegetative growth stage plants. The OsERF115/AP2EREBP110 overexpressing (OE) plants exhibited higher proline level and increased expression of a proline biosynthesis P5CS1 gene. Phenotyping of water use dynamics of the individual plant indicates that the OsERF115/AP2EREBP110-OE plant exhibited better water saving traits under heat and drought combined stress. Our combined results suggest the potential use of OsERF115/AP2EREBP110 as a candidate gene for genetic engineering approaches to develop heat and drought stress-tolerant crops.
Abstract
The purpose of this study is to analyse the proposed liquid desiccant absorber with low solution flow rate compared with the conventional packbed-type absorber. The total exergy destruction ...and exergy efficiency were estimated to assess the system performance. To determine the total exergy destruction and exergy efficiency, it was predicted that the specific thermal and chemical exergy in the inlet and outlet both air and solution side of the absorber. The results indicated that the average total thermal and chemical exergy destruction is 0.054 kW and 0.080 kW in the proposed system while it is 0.292 kW and 0.093 kW in the conventional absorber. The exergy efficiency is 0.573 and 0.114 on average in the proposed and conventional absorber, respectively.
To reduce carbon emissions, active research is being conducted on replacing the heating equipment using fossil fuels with heat pumps. While heat pumps still utilize electricity and have associated ...carbon emissions, they possess the potential to consistently decrease carbon emissions owing to the growing availability of renewable energy sources.
In this study, the applicability of a heat pump system capable of supplying 86 °C hot water for heating a semiconductor fabrication plant was verified. In addition, there are a few results considering the energy saving effect that can be obtained from the heat source. Therefore, reflecting the characteristics of a semiconductor fabrication plant, which requires a huge cooling load to remove heat from equipment even in winters, a cascade heat pump system using a chiller as a low-cycle heat pump was proposed. Compared to a boiler, the heat pump system has the advantage of reducing the load on the typical chiller system as it can supply cold and hot water.
On comparison, the cascade heat pump system, which incorporates the energy-saving effect derived from the heat source, demonstrated 66 % of primary energy and 56 % carbon emissions than the boiler. Consequently, the cascade heat pump outperformed the boiler system.
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► ZIF-8 membranes were synthesized by one step in situ method using sodium formate. ► During in situ growth sodium formate reacts with zinc source to form zinc oxide layer on the ...support. ► Zinc oxide layer promotes heterogeneous nucleation and acts a secondary metal source. ► Sodium formate promotes heterogeneous nucleation for other ZIF systems yielding ZIF-7, ZIF-90, Zn(Im)2 (ZIF-61 analogue), SIM-1 films.
Zeolitic imidazolate frameworks (ZIFs), a sub-class of metal–organic frameworks (MOFs), are noted for their remarkable thermal and chemical stability, tunable microporous channels, and tailorable physical/chemical properties. When synthesized as films, they hold great potentials for gas sensing, catalytic membrane reactor, and gas separation membrane applications. Here, we report one step in situ synthesis of ZIF-8 membranes on unmodified porous α-alumina supports in the presence of sodium formate. In this in situ method, sodium formate plays a critical role for formation of well-intergrown continuous ZIF-8 membranes. Sodium formate was found to enhance the heterogeneous nucleation of ZIF-8 crystals on alumina supports as well as to promote intergrowth of ZIF-8 crystals. It was confirmed that sodium formate reacts with zinc source to form zinc oxide layers on α-alumina supports, which in turn promote heterogeneous nucleation. ZIF-8 membranes show molecular sieving behavior, favoring smaller molecules. It was found that sodium formate promotes heterogeneous nucleation in other ZIF systems as well, leading to continuous films of ZIF-7, Zn(Im)2 (ZIF-61 analog), ZIF-90, and SIM-1.
ZIF-67, a Co-substituted ZIF-8 structure, is investigated as a candidate for the industrially highly demanding propylene/propane separation, with the use of computational techniques for the first ...time. A new force field for the ZIF-67 framework based on density functional theory calculations is reported along with a recently developed force field for ZIF-8. The new force field is validated through comparison with structural data for ZIF-67 from the literature. Molecular dynamics simulations are reported for ZIF-67, showing a dramatic increase of propylene/propane corrected diffusivities ratio when compared to ZIF-8, implying a huge improvement in the separation of the mixture. The sieving mechanism of ZIF frameworks is investigated, and the results yield a dependency of the swelling motion of the gates from the bonding of the metal atom with its surrounding atoms. The presence of Co in the modified framework results in a tighter structure with a smaller oscillation of the gate opening, which leads to a narrower aperture. The results from the simulations and experiments in ZIF-67 place this new structure at the top of the candidates for propylene/propane separation.
While zeolitic imidazolate framework, ZIF‐8, membranes show impressive propylene/propane separation, their throughput needs to be greatly improved for practical applications. A method is described ...that drastically reduces the effective thickness of ZIF‐8 membranes, thereby substantially improving their propylene permeance (that is, flux). The new strategy is based on a controlled single‐crystal to single‐crystal linker exchange of 2‐methylimidazole in ZIF‐8 membrane grains with 2‐imidazolecarboxaldehyde (ZIF‐90 linker), thereby enlarging the effective aperture size of ZIF‐8. The linker‐exchanged ZIF‐8 membranes showed a drastic increase in propylene permeance by about four times, with a negligible loss in propylene/propane separation factor when compared to as‐prepared membranes. The linker‐exchange effect depends on the membrane synthesis method.
Outside the box: A postsynthetic linker exchange approach is described for preparation of ultrathin propylene‐selective ZIF‐8 membranes. As‐prepared ZIF‐8 membranes were subjected to systematic linker exchange reactions with 2‐imidazolecarboxaldehyde without compromising the grain boundary structure of the framework. The resulting membranes display the highest propylene permeance reported to date.
▶ The surface functionalization of gold nanoparticles obtanied using 4-aminothiophenol through Au-S chemistry. ▶ The functionalized gold nanoparticles were well immobilized on the graphene oxide ...surface via amide bonding. ▶ The resulting novel hybrid was investigated in detail using various techniques.
Amino—functionalized gold nanoparticles with a diameter of around 5nm were immobilized onto the surface of graphene oxide sheets (GOS) by covalent bonding through a simple amidation reaction. Pristine graphite was firstly oxidized and exfoliated to obtain GOS, which further were acylated with thionyl chloride to give acyl chloride bound GOS. Gold nanoparticles (AuNPs) were functionalized using 4-aminothiophenol in a single-phase system to introduce amino groups on their surface through the well-developed Au–S chemistry. Subsequently, amino groups of AuNPs were reacted with acyl chloride groups of GOS to form a novel hybrid material containing GOS and AuNPs. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), energy dispersive X-ray (EDX) spectroscopy, ultraviolet–visible (UV–Vis) spectroscopy were used to study the changes in surface functionalities and demonstrate the successful immobilization of AuNPs on GOS surface. High resolution transmission electron microscopy (HR-TEM), field emission scanning electronic microscopy (FE-SEM), and atomic force microscopy (AFM) were employed to investigate the morphologies of prepared AuNPs and their distribution onto the GOS surface. Thermogravimetric analysis (TGA) was used to characterize the thermal stability of the samples on heating.
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