Hydrogen is attracting attention as a low-carbon fuel. In particular, economical hydrogen production technologies without carbon emissions are gaining increasing attention. Recently, alkaline thermal ...treatment (ATT) has been proposed to reduce carbon emissions by capturing carbon in its solid phase during hydrogen production. By adding an alkali catalyst to the conventional thermochemical hydrogen production reaction, ATT enables carbon capture through the reaction of an alkali catalyst and carbon. In this study, a thermodynamic feasibility evaluation was carried out, and the effects of the process conditions for ATT with wheat straw grass (WSG) as biomass were investigated using Aspen Plus software V12.1. First, an ATT process model was developed, and basic thermodynamic equilibrium compositions were obtained in various conditions. Then, the effects of the process parameters of the reactor temperature and the mass ratio of NaOH/WSG (alkali/biomass, A/B value) were analyzed. Finally, the product gas compositions, process efficiency, and amount of carbon capture were evaluated. The results showed that the ATT process could be an efficient hydrogen production process with carbon capture, and the optimal process conditions were a reactor temperature of 800 °C, an A/B value of three, and a flow rate of steam of 6.9 × 10−5 L/min. Under these conditions, the maximum efficiency and the amount of carbon dioxide captured were 56.9% and 28.41 mmol/g WSG, respectively.
South Korea has a plan to realize a hydrogen economy, and it is essential to establish a main hydrogen pipeline for hydrogen transport. This study develops a cost estimation model applicable to the ...construction of hydrogen pipelines and conducts an economic analysis to evaluate various scenarios for hydrogen pipeline construction. As a result, the cost of modifying an existing natural gas to a hydrogen pipeline is the lowest, however, there are issues with the safety of the modified hydrogen pipes from natural gas and the necessity of the existing natural gas pipelines. In the case of a short-distance hydrogen pipeline, the cost is about 1.8 times that of the existing natural gas pipeline modification, but it is considered a transitional scenario before the construction of the main hydrogen pipeline nationwide. Lastly, in the case of long-distance main hydrogen pipeline construction, it takes about 3.7 times as much cost as natural gas pipeline modification, however it has the advantage of being the ultimate hydrogen pipeline network. In this study, various hydrogen pipeline establishment scenarios ware compared. These results are expected to be utilized to establish plans for building hydrogen pipelines and to evaluate their economic feasibility.
Menopause induces various health problems and is associated with obesity, but the association between menopausal status and obesity is unclear due to several confounding factors, such as aging and ...reduced physical activity. The objective of this study was to examine the association of menopausal status with anthropometric indices and body composition indices in South Korean women.
In this cross-sectional study, a total of 734 subjects (297 postmenopausal women, 437 premenopausal women) from five university hospitals in South Korea were included. A binary logistic regression analysis was performed to examine the association of menopause with anthropometric indices and body composition indices.
Height, body mass index, waist-to-height ratio, waist-to-hip ratio, and neck, armpit, chest, rib, waist, iliac, and hip circumferences were associated with menopausal status in the crude analysis, but these associations disappeared in the adjusted models. Among the body composition indices, menopausal status was strongly associated with total body water, skeletal muscle mass, body fat mass, and body fat percentage in the crude analysis. However, the associations with body fat mass and body fat percentage disappeared in the adjusted models. Only the associations with total body water and skeletal muscle mass remained in the adjusted models.
Most of the anthropometric indices and body composition indices were not associated with menopausal status, but total body water and skeletal muscle mass were significantly lower in postmenopausal women than in premenopausal women.
Plastic deformation of semicrystalline polyethylene has been investigated via atomistic Monte Carlo and molecular dynamics simulations. Two deformation modes are considered, both consisting of ...tensile deformation in the longitudinal direction of the lamellar stack, with either constant lateral dimensions or constant total volume. Stress−strain curves, elastic moduli, yield stresses, and strains are determined at 350 K, with deformation strain rates (in molecular dynamics) ranging from 5 × 106 to 5 × 107 s−1. Fundamentally different yield mechanisms are observed as a function of model constraints, deformation mode, and deformation strain rate. Using Monte Carlo simulations in which the interlamellar noncrystalline material is constrained between two rigid crystalline lamellae, yield stresses in the noncrystalline domain are found to be comparable to those reported previously for amorphous glasses. After yield, in the absence of topological rearrangements of the noncrystalline material, the interphase material hardens postyield with a modulus G R = 3.36 GPa; in the presence of topological rearrangement, the interphase material flows like a liquid. Using molecular dynamics in which the crystalline domains are thermalized and deformable, tensile deformation with constant total volume is accompanied by changes in the crystal stem orientation that can be attributed to crystallographic slip in the (100)001 slip system. At the slower strain rate, plastic deformation is accompanied by melting and recrystallization. Meanwhile, for the tensile deformation mode with constant lateral dimensions or for the tensile deformation mode at the faster strain rate with constant total volume, yield apparently occurs with cavitation in the interlamellar domain. Calculated stress−strain curves are constructed by balancing the nonbonded and bonded contributions to stress. The density of entanglements is characterized using Kröger’s Z algorithm and found to correlate strongly with the fraction of noncrystalline material within the semicrystalline phase.
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Various materials are used to make implantable devices such as pumps, catheters, and stimulators. However, such implants inevitably undergo biofouling, which is associated with ...non-specific proteins and cell adhesion on the material surfaces. Severe biofouling often leads to adverse tissue reactions, such as foreign body responses, and thick scar tissue formation around the implantation, which in turn hampers the function and performance of the implants. Herein, a simple and effective surface modification method using dopamine-hyaluronic acid conjugate (DA-HA) is demonstrated to implement anti-biofouling in various biomaterials. DA-HA was synthesized and utilized as a coating material and five commonly used implantable substrates (i.e., polyimide (PI), gold (Au), poly(methyl methacrylate) (PMMA), polytetrafluoroethylene (PTFE), and polyurethane (PU)) were tested for modification with DA-HA. Highly hydrophilic HA chains were immobilized on the substrate surfaces through self-polymerization of DA-HA at an alkaline pH. The DA-HA-modified substrates displayed significant resistance to both non-specific protein adsorption and cell adhesion on the surfaces. In addition, a reduction in scar tissue formation was observed in the DA-HA-coated substrates compared to the unmodified bare substrates after a 4-week subcutaneous implantation. This universal surface coating can be further implemented in various biomedical applications in which severe biofouling is highly undesirable.
Lithium transition metal pyrophosphate materials (Li2MP2O7, M: Mn, Fe, and Co) have been proposed as promising novel cathode materials for lithium ion batteries. Using atomistic simulation with ...empirical potential parameters, which has been validated on various cathode materials by Islam et al. Phil. Trans. R. Soc. A 2010, 368, 3255–3267, these new pyrophosphates are investigated to elucidate structure, defect chemistry, and Li+ ion transport pathway. The core–shell model with empirical force fields reproduces the experimental unit-cell parameters, and formation energies of intrinsic defects (Frenkel and antisite) are calculated. From migration energy calculation, it is found that the pyrophosphates without partial occupation have a 2D Li+ ion pathway. Meanwhile, under the condition of partial occupancies of Li and transition metal atoms, the diffusion pathway of Li+ ions is a 3D network.
Sorghum grain mold is the most important disease of the crop. The disease results from simultaneous infection of the grain by multiple fungal species. Host responses to these fungi and the underlying ...molecular and cellular processes are poorly understood. To understand the genetic, molecular and biochemical components of grain mold resistance, transcriptome profiles of the developing grain of resistant and susceptible sorghum genotypes were studied.
The developing kernels of grain mold resistant RTx2911 and susceptible RTx430 sorghum genotypes were inoculated with a mixture of fungal pathogens mimicking the species complexity of the disease under natural infestation. Global transcriptome changes corresponding to multiple molecular and cellular processes, and biological functions including defense, secondary metabolism, and flavonoid biosynthesis were observed with differential regulation in the two genotypes. Genes encoding pattern recognition receptors (PRRs), regulators of growth and defense homeostasis, antimicrobial peptides, pathogenesis-related proteins, zein seed storage proteins, and phytoalexins showed increased expression correlating with resistance. Notably, SbLYK5 gene encoding an orthologue of chitin PRR, defensin genes SbDFN7.1 and SbDFN7.2 exhibited higher expression in the resistant genotype. The SbDFN7.1 and SbDFN7.2 genes are tightly linked and transcribed in opposite orientation with a likely common bidirectional promoter. Interestingly, increased expression of JAZ and other transcriptional repressors were observed that suggested the tight regulation of plant defense and growth. The data suggest a pathogen inducible defense system in the developing grain of sorghum that involves the chitin PRR, MAPKs, key transcription factors, downstream components regulating immune gene expression and accumulation of defense molecules. We propose a model through which the biosynthesis of 3-deoxyanthocynidin phytoalexins, defensins, PR proteins, other antimicrobial peptides, and defense suppressing proteins are regulated by a pathogen inducible defense system in the developing grain.
The transcriptome data from a rarely studied tissue shed light into genetic, molecular, and biochemical components of disease resistance and suggested that the developing grain shares conserved immune response mechanisms but also components uniquely enriched in the grain. Resistance was associated with increased expression of genes encoding regulatory factors, novel grain specific antimicrobial peptides including defensins and storage proteins that are potential targets for crop improvement.
Reputation is a powerful mechanism to enforce cooperation among unrelated individuals through indirect reciprocity, but it suffers from disagreement originating from private assessment, noise, and ...incomplete information. In this work, we investigate stability of cooperation in the donation game by regarding each player's reputation and behaviour as continuous variables. Through perturbative calculation, we derive a condition that a social norm should satisfy to give penalties to its close variants, provided that everyone initially cooperates with a good reputation, and this result is supported by numerical simulation. A crucial factor of the condition is whether a well-reputed player's donation to an ill-reputed co-player is appreciated by other members of the society, and the condition can be reduced to a threshold for the benefit-cost ratio of cooperation which depends on the reputational sensitivity to a donor's behaviour as well as on the behavioural sensitivity to a recipient's reputation. Our continuum formulation suggests how indirect reciprocity can work beyond the dichotomy between good and bad even in the presence of inhomogeneity, noise, and incomplete information.
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