•An optimization model is developed for centralized hydrogen storage.•Centralized hydrogen storages reduce the cost compared to the decentralized model.•The economic benefits are achieved by ...consolidating dispersed storages together.•Centralized storages promotes the central hydrogen production and liquefaction.
This study involves the construction of a hydrogen supply chain optimization model using a centralized storage model that combines and consolidates flows of hydrogen from different production sites into integrated bulk storage. To supply hydrogen to a fuel cell electric vehicle station, various hydrogen supply pathways and storage configurations for different types of production technologies and transportation modes are considered. In terms of the topological structure, the centralized storage model requires fewer storage areas than the decentralized storage model. The results show that a hydrogen supply chain with a centralized storage structure advances the phase transition of central hydrogen production plants and reduces the total annual cost of the entire supply chain. The optimal hydrogen pathway is on-site steam methane reforming production in the early markets for fuel-cell electric vehicles. However, in matured markets, hydrogen is liquefied in central production plants and stored in bulk storages equipped with vaporizers. Then, the hydrogen is distributed from the central storage areas to local refueling stations via pipelines. The role of central storage areas is predicted to become important as market shares of fuel cell electric vehicle reach 15–30%; in other words, 0.28–0.56 million tonne/year of hydrogen will be demanded in 20 cities of South Korea.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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•Microbial electrosynthesis cells (MESs) were assessed for AD biogas upgrading.•Electrode-attached cells play a key role in converting CO2 to CH4 in an MES.•The MES produced 10.55L ...CH4/m2 cat /day with a final content of 96%•8.8L CH4/m2 cat /day and 95% was achieved using real AD biogas.•The energy efficiency of CH4 conversion was compared in a lab and bench-scale MES.
Upgrading biogas from anaerobic digestion (AD) has been highlighted as an alternative renewable energy source to replace geopolitically limited natural gas. The CO2 content of AD effluent is more than 40%, making it necessary to separate or increase the CH4 content to 95%. This study examined microbial electrosynthesis (MES) to convert CO2 directly to CH4 by a cathode electrode-attached cell. The MES with a −1.0 V (versus Ag/AgCl) applied cathodic potential exhibited a maximum methane production rate of 10.55 L CH4/m2 cat/day and achieved a 96% final CH4 content. Applying real biogas from a field AD plant resulted in a comparable production rate of 8.8L CH4/ m2 cat/ day with 95% CH4. The scaled-up bench MES reactor (total volume of 6L) was evaluated, and the energy efficiencies of the laboratory- and bench-scale MES were compared. The next-generation sequencing (NGS) revealed most methanogens (e.g., Methanobacterium, Methanothrix, and Methanobrevibacter) to be associated with the cathode surface rather than suspension. Cyclic voltammetry and field emission scanning electron microscopy showed that the electrode-associated cell predominantly controls the performance of the MES system. These results suggest that electrode-attached cells play a major role in the biogas upgrading of CO2 to CH4 in the MES system.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Pesticide residues in crops are widely monitored, and the residue reduction techniques at the post-harvest stage are important to maintain food safety. In dried crops, pesticide residues can be ...concentrated after dehydration, which increases concerns regarding residue risk. Therefore, the residue reduction effects of ultraviolet (UV), ozone, and photochemical advanced oxidative process (pAOP) were investigated for dried peppers at the post-harvest stage. UV
treatment reduced 59.7% of the residue concentration on average, while UV
showed a reduction of only 13.3% under 9.6 W m
of UV exposure for 24 h. Gaseous ozone treatments reduced the residue concentrations up to 57.9% on average. In contrast, the pAOP treatment reduced the concentration up to 97% and was superior to UV or ozone treatment alone. Increased drying temperature under pAOP condition resulted in higher reduction ratios at 40-80 °C. The pAOP conditions with 12 and 24 µmol/mol of ozone and UV
irradiation for 24-48 h reduced the residue concentrations to 39-67%. Particularly, difenoconazole, fludioxonil, imidacloprid, and thiamethoxam residue concentrations were drastically reduced by over 50% under 12 µmol/mol ozone of the pAOP condition, while carbendazim, fluquinconazole, and pyrimethanil were relatively stable and their concentrations reduced below 50% under 24 µmol/mol ozone of the pAOP treatment. Various drying-related quality parameters of drying peppers such as water-soluble color, capsanthin, capsaicinoids, acid value, peroxide value, and thiobarbituric acid value were slightly altered, but not significantly, under 12 µmol/mol ozone of the pAOP condition, while the peroxide value was significantly altered under the higher ozone conditions. Therefore, pAOP treatment combined with gaseous ozone can be used for reducing residual pesticides in peppers without greatly reducing quality.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Plant growth promoting rhizobacteria (PGPR) are diverse, naturally occurring bacteria that establish a close association with plant roots and promote the growth and immunity of plants. Established ...mechanisms involved in PGPR-mediated plant growth promotion include regulation of phytohormones, improved nutrient availability, and antagonistic effects on plant pathogens. In this study, we isolated a bacterium from the rhizospheric soil of a soybean field in Chungcheong buk-do, South Korea. Using 16S rRNA sequencing, the bacterium was identified as Bacillus aryabhattai strain SRB02. Here we show that this strain significantly promotes the growth of soybean. Gas chromatography-mass spectrometry analysis showed that SRB02 produced significant amounts of abscisic acid, indole acetic acid, cytokinin and different gibberellic acids in culture. SRB02-treated soybean plants showed significantly better heat stress tolerance than did untreated plants. These plants also produced consistent levels of ABA under heat stress and exhibited ABA-mediated stomatal closure. High levels of IAA, JA, GA12, GA4, and GA7, were recorded in SRB02-treated plants. These plants produced longer roots and shoots than those of control plants. B. aryabhattai SRB02 was found to be highly tolerant to oxidative stress induced by H2O2 and MV potentiated by high catalase (CAT) and superoxide dismutase (SOD) activities. SRB02 also tolerated high nitrosative stress induced by the nitric oxide donors GSNO and CysNO. Because of these attributes, B. aryabhattai SRB02 may prove to be a valuable resource for incorporation in biofertilizers and other soil amendments that seek to improve crop productivity.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
With the expansion of Internet of Things (IoT) and sensor network systems, transparent and flexible energy supply devices are becoming more vital for ultra-connected and highly convenient human ...interfaces. In particular, the mechanical energy harvesting technology using piezoelectric materials is very attractive due to the ability of direct energy conversion from wasted mechanical energy to useful electrical energy. In this work, we demonstrate a highly transparent and flexible piezoelectric energy harvester (f-PEH) using a metallic nanowire-percolated piezoelectric copolymer on a flexible plastic substrate. The silver nanowire (Ag NWs)-based conductor has been considered as a powerful future electrode material with high transparency and flexibility, while poly(vinylidene fluoride-
co
-trifluoroethylene) (P(VDF-TrFE)) is a representative high-performance piezoelectric polymer material. Based on these two attractive materials, the proposed transparent f-PEH generated an output voltage, current, and power of ∼17 V, ∼2.5 μA, and ∼12 μW, respectively, which are a record-high performance compared to previously reported transparent f-PEHs. Besides material and device characterizations, a multiphysics simulation was firmly investigated to clarify the properties of the transparent f-PEH devices. Finally, the transparent f-PEH devices were directly modified and used as a self-powered pressure sensor array (5 × 5), which well detected the pattern images of the external pressure input without serious cross-talk. This work can guide the field of transparent and flexible piezoelectric devices to the way to accomplish transparent self-powered electronics for high-performance applications.
A transparent, flexible, and self-powered pressure sensor device was developed, monitoring the discrepancy of external pressure input from different shapes.
In this study, the densification behavior and microstructural development of Inconel 718 parts fabricated by selective laser melting (SLM) were investigated with variation of the applied laser ...scanning speed. The starting materials of Inconel 718 powder particles were prepared using a gas atomization process showing uniform size distribution with high flowability. During the SLM process, the applied scan speed played a decisive role in densification during the SLM process, and that the highest density (>99%) and hardness (320 Hv0.5) could be achieved at the laser scanning speed of 800mm/s. Upon fabrication, the microstructure of Inconel 718 parts was characterized by the presence of columnar grains, due to the rapid rate of cooling of the molten pool. These grains, in particular, in XZ and YZ planes, were observed to be parallel to the building direction (Z-axis), with size ranging from several to hundreds of micrometers. It was also found that the fine cellular sub-structures, within the specified range between 0.5 and 1μm, were embedded inside each large grain with low angle boundaries (<2°). The experimental findings in this study may provide fundamental understanding of densification and microstructural characteristics induced by the laser melting process.
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•Densification and microstructural behavior of SLM IN718 parts is investigated.•Spherical IN718 powder with high flowability can be produced by gas atomization.•Optimal range of laser scan speed can be determined by microstructural analysis.•Fully densified IN718 parts can be fabricated at laser scanning speed of 800mm/s.•Columnar grains with fine cellular substructures can be observed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Abstract
Background
Mesenchymal stem cells (MSCs) may be one of candidates for disease-modifying therapy in Parkinsonian diseases. As knowledge regarding the therapeutic properties of MSCs ...accumulates, some obstacles still remain to be overcome, especially, successful clinical translation requires the development of culture systems that mimic the natural MSC niche, while allowing clinical-scale cell expansion without compromising quality and function of the cells. In recent years, priming approaches using bioactive peptide or complement components have been investigated to enhance the therapeutic potential of MSCs.
Methods
We investigated an innovative priming strategy by conditioning the MSCs with α-synuclein (α-syn). To induce priming, MSCs were treated with different concentrations of α-syn and various time course. We evaluated whether α-syn enhances stemness properties of MSCs and priming MSCs with α-syn would modulate autophagy-related gene expression profiles.
Results
Treatment of naïve MSCs with α-syn upregulated transcriptional factors responsible for regulation of stemness, which was associated with the elevated expression of genes involved in glycolysis and cell re-programming. Primed MSCs with α-syn enhanced the expression of autophagy-regulating miRNA, and exosomes derived from primed MSCs were packed with autophagy-associated miRNA. In α-syn-overexpressing neuronal cells, primed MSCs with α-syn enhanced neuronal viability relative to naïve MSCs, through the induction of autophagy and lysosome activity. Animal study using an α-syn-overexpressing mice showed that the pro-survival effect of MSCs on dopaminergic neurons was more prominent in primed MSC-treated mice compared with that in naïve MSC-treated mice.
Conclusions
The present data suggest that MSC priming with α-syn exerts neuroprotective effects through augmented stemness and possibly the enhancement of autophagy-mediated α-syn modulation in Parkinsonian models.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
•Energy consumption, cost, and CO2 emission of hydrogen liquefaction were optimized.•Maximum LNG usage and minimum GH2 and N2 flowrates ensure optimal energy and cost.•If cost increases 45% from the ...base case, total CO2 emissions could decrease 38%.•Specific energy consumption of optimized case shows an increase of 0.37 kWh/kg-LH2.
Liquid hydrogen is gaining increasing attention owing to its high energy density as 10.1 MJ/L compared to gaseous hydrogen as 5.6 MJ/L at 700 bar. However, the energy required for its cryogenic processes is significant. To reduce this energy demand, liquefied natural gas (LNG) cooling was introduced in addition to a nitrogen refrigerant to the hydrogen liquefaction process. The resultant hydrogen production from the steam methane reforming process via LNG emits carbon dioxide. Therefore, it is necessary to consider both energy and CO2 emission when optimizing this system. To minimize these factors, single and multi-objective optimizations were performed, as well as a cost analysis in order to determine the optimal performance. The results of multi-objective optimization reveal that the CO2 emissions decrease by 38%, whereas the total investment cost is increased by 45% compared to the base case. The specific energy consumption is increased from 10.76 kWh/kg-LH2 to 11.13 kWh/kg-LH2. Therefore, the compromise between the cost and the CO2 emissions is made in the proposed case. These results will provide valuable insights regarding the economic demand and CO2 emission for future decision-making processes.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPUK, ZRSKP
This article introduces a 192-Gb 896-GB/s 12-high stacked third-generation high-bandwidth memory (HBM3 DRAM) with low power consumption and high-reliability traits. New design schemes and features, ...including internal low-voltage signaling, center strobe calibration, through-silicon via (TSV) auto-calibration, a symbol-correcting in-DRAM ECC, and machine-learning-based layout optimization, allow large amounts of data transfers among the vertically stacked base and core dies with limited delay mismatch or SI degradation, as well as reduced power consumption from low-voltage swings. Experimental results confirm 896-GB/s bandwidth operations at 1.0-V voltage conditions with up to 15% improved power efficiency.
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