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► Layered silicate AMH-3 was delaminated without the use of a swelling agent. ► The delaminated AMH-3 retains framework crystallinity in the AMH-3 layers. ► The membrane coated with ...delaminated AMH-3/Nafion can reduce methanol crossover.
Microporous layered silicate AMH-3 has a 3D ordered porous structure that is therefore very promising as a permselective barrier. However, for use as permselective barrier, the removal of the Na+ and Sr2+ cations located in the intralayer and interlayer spaces and the delamination of an individual layer must be carried out. We successfully obtained delaminated AMH-3 by acid-hydrothermal treatment without the use of swelling agent. The delamination conditions have been optimized to find the best morphology for use as permselective barrier. The pristine AMH-3 and the delaminated AMH-3 were characterized with FE-SEM, N2 adsorption, ICP-AES, 29Si MAS NMR, FT-IR, and WXRD analyses. These results show that the delaminated AMH-3 has a more ordered pore structure than the pristine AMH-3 and that it retains framework crystallinity in the AMH-3 layers. The methanol permeability, proton conductivity and liquid uptake of Nafion membrane coated with a delaminated AMH-3/Nafion nanocomposite layer were examined. This type of membrane was found to exhibit a lower methanol permeability than neat Nafion and to maintain a high proton conductivity. We can thus conclude that delaminated AMH-3 is potentially good permselective barrier for the reduction of methanol crossover in DMFCs.
species are the most important sources of antibacterial, antifungal, and phytotoxic metabolites. In this study, cycloheximide (CH) and acetoxycycloheximide (ACH) were isolated from the fermentation ...broth of
sp. JCK-6092. The antifungal and phytotoxic activities of the two compounds (CH and ACH) and a cycloheximide derivative, hydroxycycloheximide (HCH), were compared. CH exhibited the strongest antagonistic activity against all the true fungi tested, followed by ACH and HCH. However, both CH and ACH displayed similar mycelial growth inhibitory activities against several phytopathogenic oomycetes, and both were more active than that of HCH. Disparate to antifungal ability, ACH showed the strongest phytotoxic activity against weeds and crops, followed by HCH and CH. ACH caused chlorophyll content loss, leaf electrolytic leakage, and lipid peroxidation in a dose-dependent manner. Its phytotoxicity was stronger than that of glufosinate-ammonium but weaker than that of paraquat in the
experiments. CH and its derivatives are well-known protein synthesis inhibitors; however, the precise differences between their mechanism of action remain undiscovered. A computational study revealed effects of CHs on the protein synthesis of
(oomycetes),
(true fungus), and
(plant) and deciphered the differences in their biological activities on different targets. The binding energies and conformation stabilities of each chemical molecule correlated with their biological activities. Thus, molecular docking study supported the experimental results. This is the first comparative study to suggest the ribosomal protein alteration mechanisms of CHs in plants and fungi and to thus show how the protein inhibitory activities of the different derivatives are altered using molecular docking. The correlation of structures features of CHs in respect to bond formation with desired protein was revealed by density functional theory. Overall collective results suggested that CHs can be used as lead molecules in the development of more potent fungicides and herbicides molecules.
Photoelectrodes composed of mesoporous TiO2 spheres as scattering centers and TiO2 nanoparticles as the binder were fabricated and tested with the aim of improving the energy conversion efficiency of ...dye-sensitized solar cells (DSSCs). In order to achieve the dispersion of the TiO2 spheres in suspension and improve their connectivity in the electrodes, acid treatment and a compression method were applied. These electrodes composed of TiO2 spheres and nanoparticles enable the fabrication of high performance DSSCs, because of the light scattering of the TiO2 spheres and the dye-loading capacity of their high surface areas. The energy conversion efficiency of composite-type photoelectrode was found to be 7.66%, which is higher than that of nanocrystal electrode (4.50%). We can thus conclude that high energy conversion efficiency was achieved with a composite-type photoelectrode, without the use of an anti-reflection coating or a back-scattering layer.
Highly dispersed TiO2 spheres with tunable cluster sizes (approximately 500 and 1000nm) in suspension have been prepared through treatment with nitric acid. The mesoporous TiO2 spheres reveal that the materials have well-defined spherical structures with primary particle sizes of 10nm. All of the samples have mesoporous structures, and the wormhole-like mesopores form special closely interconnected nanoparticles. Display omitted
•Electrode with mesoporous TiO2 spheres for dye-sensitized solar cell is fabricated.•We prepare size-tunable mesoporous TiO2 spheres via sol-gel method.•Mesoporous TiO2 spheres are dispersed in suspension via acid treatment.•TiO2 spheres act as scattering centers without damaging the dye-loading capacity.•An energy conversion efficiency of 7.66% has been achieved by using the electrode.
This study demonstrates a method to estimate floating oil slick thickness based on remote sensing of thermal infrared contrast. The approach was demonstrated for thick oil slicks from natural seeps ...in the Coal Oil Point seep field, offshore southern California. Airborne thermal infrared and visible spectrum remote sensing imagery were acquired along with position and orientation data by the SeaSpires™ science package. Remote sensing data were acquired in the cross-slick direction of oil slick segments that were targeted for collection, termed “collects.” A collect consisted of booming, skimming, and offloading the oil slick segment into buckets for analysis at the laboratory. Each collect provided an in-scene calibration point of oil thickness versus brightness temperature contrast, ΔTB, where TB is the sensor-reported temperature based on the emitted thermal radiation and differs from the true temperature due to the oil's emissivity. ΔTB is the TB difference between the oil and oil-free sea surface. Thus, this study is a reverse planned oil-release experiment that demonstrates the value of natural seeps for oil spill science.
• Novel approach to quantify floating oil thickness
• Custom modified weir skimmer used with added floor and structural strengthening
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•We demonstrate here the fabrication of bowl-shaped TiO2 aggregates via electrospray.•The prepared bowl-shaped TiO2 are micrometer in size and have good morphology.•These aggregates have high ...specific surface area of up to 93.10m2/g.•These aggregates have relatively large pores with a mean size of 4.68nm.•Bowl-shaped TiO2 have superior light scattering abilities.
We demonstrate here the fabrication of a novel morphology of bowl-shaped TiO2 aggregates via a facile electrospray technique using TiO2 nanowires. These have been prepared by using lauric acid via solvothermal synthetic route. The modulation of surface energies of the different crystallographic faces through the use of lauric acid is the key parameter for the anisotropic growth. These aggregates have high specific surface area of up to 93.10m2/g, and relatively large pores with a mean size of 4.68nm. These porous structures can provide a high number of active adsorption sites and act as photo-related reaction centers. The prepared bowl-shaped TiO2 are in micrometer size and have good morphology and high specific surface area. A possible mechanism for the formation of bowl-shaped TiO2 aggregates is also proposed, based on the results. The light scattering properties of bowl-shaped architectures are characterized by the UV–Vis spectrometry. The superior light scattering abilities of bowl-shape makes them promising architectures for applications in the photovoltaic devices.
Remote-sensing optical payloads, especially hyperspectral imagers, have particular issues with stray light because they often encounter high-contrast target/background conditions, such as sun glint. ...While developing an optical payload, we usually apply several stray-light analysis methods, including forward and backward analyses, separately or in combination, to support lens design and optomechanical design. In addition, we often characterize the stray-light response over a full field to support calibration, or when developing an algorithm to correct stray-light errors. For this purpose, we usually use forward analysis across the entire field, but this requires a tremendous amount of computational time. In this paper, we propose a sequence of forward-backward-forward analyses to more effectively investigate the through-field response of stray light, utilizing the combined advantages of the individual methods. The application is an airborne hyperspectral imager for creating hyperspectral maps from 900 to 1700 nm in a 5-nm-continuous band. With the proposed method, we have investigated the through-field response of stray light to an effective accuracy of 0.1°, while reducing computation time to 1/17th of that for a conventional, forward-only stray-light analysis.
To enhance the performance (i.e., mechanical properties and ionic conductivity) of pore-filling polymer electrolytes, titanium dioxide (TiO2) nanoparticles are added to both a porous membrane and its ...included viscous electrolyte, poly(ethylene oxide-co-ethylene carbonate) copolymer (P(EO-EC)). A porous membrane with 10wt.% TiO2 shows better performance (e.g., homogeneous distribution, high uptake, and good mechanical properties) than the others studied and is therefore chosen as the matrix to prepare polymer electrolytes. A maximum conductivity of 5.1X10-5Scm-1 at 25 deg C is obtained for a polymer electrolyte containing 1.5wt.% TiO2 in a viscous electrolyte, compared with 3.2X10-5Scm-1 for a polymer electrolyte without TiO2. The glass transition temperature, Tg is lowered by the addition of TiO2 (up to 1.5wt.% in a viscous electrolyte) due to interaction between P(EO-EC) and TiO2, which weakens the interaction between oxide groups of the P(EO-EC) and lithium cations. The overall results indicate that the sample prepared with 10wt.% TiO2 for a porous membrane and 1.5wt.% TiO2 for a viscous electrolyte is a promising polymer electrolyte for rechargeable lithium batteries.
Carbide-derived carbon (CDC) is an attractive anode material for Li-ion battery applications because diverse pore textures and structures from amorphous to highly ordered graphite can be controlled ...by changing the synthesis conditions and precursor, respectively. To elucidate the unique cycling behavior of the post air-treated CDC anode, electrochemical performance was studied under variation of C-rates with structural changes before and after cycling. By tailoring the pore texture of CDCs as removal of amorphous phase by post air-activation, the anode electrode showed a high increase of capacity under prolonged cycling and under high C-rate conditions such as 0.3-1.0 C-rates. The discharge capacities of the treated CDC increased from 400 mAh g super(-1) to 913 mAh g super(-1) with increasing cycle number and were close to high initial irreversible value, 1250 mAh g super(-1) at the 220th cycle under a 0.1C-rate condition, which are unique and unusual cyclic properties in carbon anode applications. Under high C-rate conditions, the discharge capacities started to increase from around 160 mAh g super(-1) and values of 415 mAh g super(-1), 372 mAh g super(-1) and 336 mAh g super(-1) were observed at 0.3, 0.5, and 1.0 C-rates, respectively, at 600 cycles, demonstrating stable capacity performance.
This study presents NH4F salt inclusion approach to creating additional mesopores within microporous zeolite Y. Etching with NH4F salts embedded in the supercages perfomrs the localized dissolution ...within the zeolite crystals to effectively create additional interconnected mesopores without deteriorating crystallinity. Our work provides a novel idea for tailoring pore architecture to design desirable porous materials.
Creation of additional mesopores within zeolite Y through etching with embedded NH4F salts. Display omitted
•A new approach to creating additional mesopores in microporous zeolite using NH4F salt as an etchant was proposed.•Etching with embedded NH4F salts in the cavities of zeolite Y performs the preferential dissolution in the intracrystalline region of the zeolite to create additional interconnected mesopores.•Additional mesoporosity was developed without formations of cracks or holes onto the crystals and the loss of crystallinity.
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