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Analyzing exosomal miRNA profiles in tetralogy of fallot fetuses’ amniotic fluid
Automatic X-ray teeth segmentation with grouped attention
Measurement and spatio-temporal evolution of high-quality industrial development level in China
Effect of empagliflozin on weight in patients with prediabetes and diabetes
Conditions for shale gas accumulation and the gas-bearing factors of the Wufeng-Longmaxi formation in the Laifeng–Xianfeng area
Assessing the impact of community-based homestay experiences on tourist loyalty in sustainable rural tourism development
Characterization and assessment of hydrogen leakage mechanisms in salt caverns
AbstractSalt caverns are widely regarded as a suitable option for the underground storage of hydrogen. However, an accurate assessment of the hydrogen leakage through the walls of salt caverns into the surrounding formations remains crucial. In this work, the flow of hydrogen into the surrounding formation is evaluated by assuming that salt rock consists of bundles of tortuous nano-capillary tubes. A formulation was then proposed to model the flow in linear and radial domains. The formulations are based on a newly proposed unified gas flow model that is valid for the entire range of Knudsen numbers and accounts for gas slippage, bulk diffusion, and Knudsen diffusion. A finite-difference approximation with an iterative procedure was then used to treat the nonlinearity and solve the presented formulations. The formulations were validated against the experimental data reported in the literature. The results obtained indicated that for hydrogen flow over a wide range of pore radii and operating pressures and temperatures, the slippage flow regime must be considered. In a salt cavern with relevant dimensions and operating conditions, the cumulative hydrogen leakage after 30 years of cyclic storage was only 0.36% of the maximum storage capacity. It was also noticed that most of the leaked hydrogen would flow back into the salt cavern at times when the pressure in the salt cavern is lower than the surrounding pressure, e.g. during production and subsequent idle times. At low storage pressure and very tight salt rock, diffusion was the most important mechanism for hydrogen transport. At a high pressure though, viscous flow became the predominant leakage mechanism. The presence of a thin interlayer such as mudstone, carbonate, and anhydrite in the body of the salt rock can have a significant impact on the amount of leakage. It appeared that although increasing the maximum operating pressure from 120 to 135 bar only led to an 11.9% increase in the maximum storage capacity, the hydrogen loss increased significantly from 0.007% at 120 bar to 0.36% at 135 bar. Furthermore, although the absolute leakage rate for natural gas storage was higher than that for hydrogen storage, the relative leakage rate in relation to the maximum salt cavern capacity was much lower. The leakage range was also lower for natural gas storage compared to hydrogen storage. The formulations presented and the results obtained in this study can help to have a better understanding of the salt caverns when it comes to large-scale hydrogen storage.
Quantum implementation of the classical guided image filtering algorithm
Imply on diagnosis and early prognosis of preoperative [68Ga]Ga-PSMA-11 PET/CT in patients with suspected brain tumours of glial origin
Accuracy and operation procedure of robotic computer-aided implant surgery
Synergistic design of CuO/CoFe₂O₄/MWCNTs ternary nanocomposite for enhanced photocatalytic degradation of tetracycline under visible light
Spatial distribution and determinants of anemia among under-five children in Mozambique
Prognostic value of [18F]FDG PET/CT in patients with idiopathic pulmonary fibrosis
Carboxylated nanocellulose from quinoa husk for enhanced protease immobilization and stability of protease in biotechnological applications
AbstractHerein, an efficient and feasible approach was developed to oxidize low-cost agricultural waste (quinoa husk, QS) for the synthesis of carboxylated nanocellulose (CNC). The as-prepared rod-like CNCs (average diameter of 10 nm and length of 103 nm) with a high specific surface area (173 m2/g) were utilized for the immobilization of a model protease enzyme (PersiProtease1) either physically or via covalent attachment. For chemical immobilization, CNCs were firstly functionalized with N, N′-dicyclohexylcarbodiimide (DCC) to provide DCNCs nanocarrier which could covalently bond to enzyme trough nucleophilic substitution reaction and formation of the amide bond between DCNCs and enzyme. The immobilization efficiency, activity, stability, kinetic parameters, and reusability of covalently attached and physically immobilized PersiProtease1 were similar to those of the free enzyme. Enzyme immobilization resulted in higher thermal stability of the enzyme at elevated temperatures (> 80 °C), and the covalently immobilized enzyme displayed higher reusability than its physically immobilized form (56% vs. 37% activity, after 15 consecutive cycles), which would be rooted in a more tightly attached and less leached enzyme in the case of PersiProtease1/DCNCs. This study demonstrates the significance of using agricultural by-products and the enhanced performance and stability of immobilized proteases.
Comparison of the prognosis and lymph node metastasis between no tumor budding and low-grade tumor budding in T1 and T2 colorectal cancer
Hypoxia traits imprinted in otolith δ13C from individual to global scales
Abstract Hypoxia tolerance and its variation with temperature, activity, and body mass, are critical ecophysiological traits through which climate impacts marine ectotherms. To date, experimental determination of these traits is limited to a small subset of modern species. We leverage the close coupling of carbon and oxygen in animal metabolism to mechanistically relate these traits to the carbon isotopes in fish otoliths (δ13Coto). The model reproduces the major empirical patterns in δ13Coto at individual to global scales. The weak dependence on body size and strong, non-linear, dependence on temperature reflect the same balance between metabolism and ventilatory gas exchange that underlies organisms’ hypoxia tolerance. The global relationship between temperature and δ13Coto records both the fractionation by aragonite precipitation and the variation in hypoxia traits across ocean biomes. Because hypoxia tolerance is imprinted on both otolith geochemistry and species biogeography, the model allows the aerobic limits of species geographic ranges to be predicted from fish δ13Coto. This physiologically grounded model provides a foundation for the use of otolith chemistry to reconstruct modern spatial patterns and paleoceanographic changes in key traits that shape aerobic habitat of aquatic species.
Production and properties of particleboard and paper from waste poppy straw
AbstractDue to the scarcity of wood in some countries, it is necessary to replace it with other raw materials and at the same time use the waste material. The aim of this research is to use poppy waste straw for the efficient conversion of possible lignocellulosic materials – pulps and particleboards. Their suitability for the production of composites is assessed on the basis of selected physical or mechanical properties. Tensile strength index, burst strength index and air permeability by Gurley have been identified as critical properties of pulp made from poppy straw through two delignification methods. The better mechanical properties, i.e., tensile strength index, were achieved at 52.7 N·m/g for the sodium pulp, but the nitrate-alkali method also showed corresponding values at 45.9 N·m/g. Similar parameters to those of bagasse or similar fast-growing plants were achieved in particleboard production. The results of this research are used to evaluate poppy straw as an alternative raw material to produce biocomposites.
All-electrical recursive generation and time-domain mode division multiplexing of Hermite–Gaussian pulses for optical, THz and RF links
AbstractSpace division multiplexing (SDM) with Hermite Gaussian (HG) modes, for instance, can significantly boost the transmission link capacity. However, SDM is not suitable in existing single mode fiber networks, and in long-distance wireless, microwave, THz or optical links, the far-field beam distribution may present a problem. Recently it has been demonstrated, that time domain HG modes can be employed to enhance the link capacity. However, implementing this method in wireless or fiber-based transmission systems is impractical due to the need for highly complex setups involving specialized lasers, wave shapers and other advanced devices. We propose a simple and fully electrical time-domain mode-division-multiplexing (TD-MDM) method based on the recursive generation of Hermite–Gaussian (HG) modes. It utilizes Gaussian pulse sequences, sawtooth signals, RF multipliers, adders, amplifiers, and Mach–Zehnder modulators for efficient multiplexing and demultiplexing. We show the time and bandwidth performance of 4 multiplexed orthogonal modes in transmitting 8 Gbps communication data (4 × 2 Gbit/s), demonstrating the feasibility of the recursive generation and multiplexing technique for TD-MDM with HG modes. The data rates were restricted by our experimental capabilities. With state-of-the-art equipment the method can easily be scaled to the terabit per second range.