Forward osmosis (FO) has attracted research attention as the energy-effective water separation process. For a FO process, it is important to prevent leakage of a solute of the DS. As a low-leakage ...solute, a branched thermo-responsive oligomer, pentaerythritol-oligo(ethylene oxide)m-b-(butylene oxide)n oligomers (PEBs), had been reported. In this study, the relationship between the chemical structure and the permeability of the PEBs through a FO membrane had been investigated in detail. For the detailed investigation, the mole fraction of each component having different absolute molecular weights in the PEBs was determined by the MALDI/TOF-MS, then the permeabilities of the components through the FO membrane were independently quantified. As the result, for the PEBs with low absolute molecular weight, the permeability of the PEBs was strongly affected by the molecular weight of the PEBs. On the other hand, for the PEBs with high absolute molecular weight, it was confirmed that the permeability of the PEBs was affected by the hydrophobicity of the PEBs. Conclusively, it was indicated that not only the molecular weight but also the affinity between the PEBs and the FO membrane is important for the reverse solute flux.
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•Branched oligomer draw solutes with several molecular weights (Mw) were synthesized.•Permeability of the oligomers through a forward osmosis (FO) membrane was measured.•The components permeated through the FO membrane were quantified by mass spectra.•Permeability of oligomers with small absolute Mw was affected by the diffusivity.•Affinity between the oligomer and the FO membrane was important for permeability.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The controlling factor of the CO2 permeance of an ion gel membrane containing a task-specific ionic liquid (tetraphosphonium prolinate) as the CO2 carrier was investigated. Tough double-network (DN) ...ion gel membranes with different thicknesses were fabricated, and their CO2 permeances were evaluated. The results showed that the CO2 permeance of the DN ion gel membrane was not inversely proportional to the membrane thickness, indicating that the CO2 permeance of the membrane was not controlled by diffusion. A theoretical analysis of the relationship between CO2 permeance and the thickness of the membrane revealed that the CO2 stripping rate at the permeate side greatly affected the CO2 permeance of the DN ion gel membrane. Therefore, increasing the decomposition reaction rate of the CO2–carrier complex would be the most important issue for achieving a high CO2 permeance of ion gel membranes containing a task-specific ionic liquid.
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Conglomerate of the Lower Jurassic Kuruma Group contains microfossil-bearing clasts. In the present study, these microfossils were investigated via the hydrofluoric acid (HF)-etched surfaces of the ...clasts and residues produced during acid treatment. As a result, Permian (mainly Guadalupian–Lopingian) radiolarians were obtained from mudstone and chert clasts; spicules of indeterminate age were obtained from the chert clasts. The mudstone clasts were derivable from the Akiyoshi, Ultra-Tamba, Maizuru, and/or Hida-Gaien belts or equivalent units, while the spicule-dominated chert clasts likely originated from the Akiyoshi belt or equivalent units. Except for tuff and acidic volcanic rocks, the clast components of the Kuruma Group in this study are similar to the component rocks of the Akiyoshi belt.
The light absorption properties of particulate and dissolved materials strongly influence the propagation of visible light in oceanic waters and therefore the accuracy of ocean color algorithms. ...While the general absorption properties of these materials have been reported for Arctic waters, their seasonal variability remains unknown. We investigated the light absorption coefficients of phytoplankton aϕ(λ), nonalgal particles aNAP(λ), and colored dissolved organic matter aCDOM(λ) in both coastal and oceanic waters of the western Arctic Ocean from spring to autumn. Values for the chlorophyll a–specific absorption coefficient of phytoplankton a*ϕ(440) declined significantly from the ice melt period in the early spring to the summer. Using high‐performance liquid chromatography, we show that the decrease in a*ϕ(440) was due to a strong package effect that overwhelmed the influence of the pigment composition. A decrease in the aNAP(λ) values from spring and summer to autumn likely originated from a decrease in the concentration of phytoplanktonic detritus. The aCDOM(λ) near the surface decreased by 34% from spring to summer as a result of photobleaching by solar radiation. The colored dissolved organic matter (CDOM) absorption values then increased significantly during autumn, resulting from the cumulative injection of Alaskan Coastal Waters into the Arctic as well as CDOM generated in situ. Our results suggest that all of the absorption components are tightly linked to biogeochemical processes, and thus the seasonal variability in aϕ(λ), aNAP(λ), and aCDOM(λ) should be taken into account in bio‐optical models.
A micro-double-network (μ-DN) ion gel membrane was fabricated using nonvolatile network precursors comprising a presynthesized cross-linkable polymer as the organic part, silica nanoparticles as the ...inorganic part, and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (C4mimTf2N). The mechanical properties of the ion gel were effectively improved through optimizing the molecular weight of the cross-linkable polymer and the organic/inorganic network composition. The μ-DN ion gel membranes exhibited the CO2 permeability of approximately 920 Barrer under atmospheric pressure, which is much higher than those of the classic double-network ion gel membranes fabricated using volatile network precursors (556 Barrer) and the supported ionic liquid membranes (617 Barrer). The membrane also has good pressure resistance and long-term stability. The μ-DN ion gel membrane formed by nonvolatile network precursors shows good mechanical properties and high CO2 separation performance, which make it a good candidate base material for developing high-permeance thin ion gel membranes.
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Radiolaria is a valuable age index fossil through the Phanerozoic. This article describes the characteristics of the non-taxonomic names of closed nassellarian radiolarians, that is, di-segmented ...closed nassellarian (DiCN), tri-segmented closed nassellarian (TrCN), tetra-segmented closed nassellarian (TeCN), and multi-segmented closed nassellarian (MuCN), based on the number of segments. This article points out a potential as a practical age index for DiCN and TrCN. The TrCN occurrence indicates a Jurassic–Cretaceous age. In particular, the waterdrop-shaped TrCN-dominant occurrence suggests a Middle–Late Jurassic age; the spherical TrCN-dominant occurrence suggests a Cretaceous age. DiCN occurrence indicates a Jurassic–Cretaceous age, and abundant in the Middle Jurassic–Cretaceous.
We report on a process for estimating the retraction force of a pseudopodium of a radiolarian specimen using a video recording of its behavior. Specifically, we focused on the retraction of the axial ...projection, which is the longest and the thickest pseudopodium, using the video recording of the movement of the specimen towards the container bottom to which its axial projection tip had adhered. Our approach consisted of three steps: shape approximation using seventh-order polynomials, estimation of the movement speed, and numerical simulation of the fluid flow around an object with the same shape as the specimen. The retraction force was estimated to be approximately 2.22 × 10−10 N.
Organic solvent reverse osmosis (OSRO) is currently considered as an energy-efficient membrane technology for separation of organic liquid mixtures. The conventional hydrophilic polyamide thin film ...(TFC) membrane was previously reported to be chemically stable and capable of separation of organic liquids with varying polarity. In order to augment the performance and applicability of the TFC membrane for a wider array of organic liquids, we report the preparation of a hydrophobic fluorine-incorporated TFC membrane for OSRO. 5-Trifluoro-1,3-phenylenediamine (TFMPD) and trimesoyl chloride (TMC) were used as the respective fluorine-containing hydrophobic diamine monomer in aqueous phase and acid chloride in organic phase. The hydrophobic membrane was able to allow the permeation of nonpolar solvents, such as aliphatic and aromatic hydrocarbons, which could not permeate through the conventional hydrophilic polyamide membranes using m -phenylenediamine (MPD) as a diamine monomer. In addition, the OSRO test showed high performance in toluene mixed solvent systems with selective permeation of toluene and 93.9% rejection of 1,3,5-triisopropylbenzene (TIPB). The successful preparation of a hydrophobic fluorine-incorporated polyamide TFC membrane suitable for OSRO for separation of nonpolar organic liquid mixtures has proven to be simple, cost-efficient, and highly-scalable.
The monitoring of Chlorophyll-a (Chl-a) concentration in high northern latitude waters has been receiving increased focus due to the rapid environmental changes in the sub-Arctic, Arctic. Spaceborne ...optical instruments allow the continuous monitoring of the occurrence, distribution, and amount of Chl-a. In recent years, the Ocean and Land Color Instruments (OLCI) onboard the Sentinel 3 (S3) A and B satellites were launched, which provide data about various aquatic environments on advantageous spatial, spectral, and temporal resolutions with high SNR. Although S3 OLCI could be favorable to monitor high northern latitude waters, there have been several challenges related to Chl-a concentration retrieval in these waters due to their unique optical properties coupled with challenging environments including high sun zenith angle, presence of sea ice, and frequent cloud covers. In this work, we aim to overcome these difficulties by developing a machine-learning (ML) approach designed to estimate Chl-a concentration from S3 OLCI data in high northern latitude optically complex waters. The ML model is optimized and requires only three S3 OLCI bands, reflecting the physical characteristic of Chl-a as input in the regression process to estimate Chl-a concentration with improved accuracy in terms of the bias (five times improvements.) The ML model was optimized on data from Arctic, coastal, and open waters, and showed promising performance. Finally, we present the performance of the optimized ML approach by computing Chl-a maps and corresponding certainty maps in highly complex sub-Arctic and Arctic waters. We show how these certainty maps can be used as a support to understand possible radiometric calibration issues in the retrieval of Level 2 reflectance over these waters. This can be a useful tool in identifying erroneous Level 2 Remote sensing reflectance due to possible failure of the atmospheric correction algorithm.
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