Steam reforming of oxygenated hydrocarbons such as methyl linoleate offers a renewable pathway for hydrogen and synthesis-gas production from biodiesel-derived feedstocks. Wall-coated catalytic microchannel reactors provide the heat and mass-transfer intensification required for this highly endothermic reaction, eliminating secondary cracking and carbon deposition typically observed under diffusion-limited conditions in packed beds. Palladium was uniformly deposited on Fe-Al intermetallic substrates via electroless plating from dilute PdCl2 solutions (<0.5 mM), forming submicron catalyst islets with clean metal-substrate interfaces after reduction in an N-2-H-2 atmosphere and thermal conditioning at 903-1273 K. Steam-reforming experiments at a steam-to-carbon ratio (S/C) of 7.75 exhibited nearly isothermal operation and rapid gas-phase equilibration. The overall reaction rate was surface-controlled and first-order with respect to methyl linoleate partial pressure. The microchannel configuration effectively eliminated diffusion limitations and suppressed carbon formation at S/C ratios above the thermodynamic decomposition threshold. Experiments performed at short mean residence times (55-62 ms) maintained conversions below equilibrium levels under industrially relevant temperatures. The overall reforming rate was controlled by surface kinetics and showed a first-order dependence on the partial pressure of methyl linoleate. This confirms that both internal and external diffusion limitations were effectively eliminated by the microchannel design. At 1173 K, hydrogen yields of about 40% were achieved, in close agreement with the numerical simulations of the coupled convection-diffusion-reaction model. This strong agreement between experiment and model validates the extracted kinetic parameters and confirms the suitability of wall-coated microchannel reactors for intensified biodiesel steam reforming under industrially relevant conditions.
The structure of coal determines its reactivity and products in direct liquefaction, and the production of aromatic chemicals from the abundant aromatic structures in coal is an important route for high-value conversion. In this study, an atomic-scale molecular model was implemented under the dual constraints of elemental composition and carbon skeleton based on elemental analysis, FTIR, and C-13 NMR. Because the depolymerization of the coal macromolecular network was initiated by thermal cleavage of weak bridge bonds, key chemical bonding descriptors (XCal-Cal, XCar-Cal, and XCal-O) were extracted from the model, and a quantitative structure-performance relationship model correlating these descriptors with aromatic compound yield was established. The results indicated that the proposed model followed a weighted average equation (Y-aromatic = 62.4X(Cal-O) + 44.5X(Cal-Cal) + 40.0X(Car-Cal)), in which the coefficients corresponded to the "theoretical reference yield" of the respective bonds. All three bonding descriptors positively contributed to aromatic compound yield (C-al-O > C-al-C-al > C-ar-C-al). In addition, the established model showed high accuracy (R-2 > 0.98), and an accurate prediction of aromatic compound yields from coal structure was achieved. This suggests that the formation of aromatic compounds mainly relies on the abundance of bridge bonds. In particular, C-al-O dominated by ether bonds acted as a critical "network depolymerization switch", and its preferential cleavage directly triggered the primary depolymerization of the coal macromolecular network. Hence, C-al-O dominated the formation of aromatic compounds. Consequently, weak covalent bonds, such as C-al-O, were redefined from traditional gas precursors to a core structural factor governing aromatic compound formation. This study establishes a quantitative predictive relationship between aromatic compound yield in direct coal liquefaction and microscopically computable bonding descriptors, providing theoretical references and tools for molecular structure-based feedstock evaluation and targeted conversion process regulation.
Abstract Many large igneous provinces (LIPs) comprise once contiguous magmatic products that are now fragmented across multiple tectonic plates. Emplacement of these voluminous magmatic products is commonly coeval with, or shortly followed by, fragmentation into constituent domains. However, the Kerguelen LIP, predominantly within the southern Indian Ocean, rifted after an unusually protracted c. 45 Myr interval post‐emplacement. To investigate this protracted post‐emplacement rifting, a recent voyage by the RV Investigator sampled the conjugate margins of the Kerguelen Plateau, William's Ridge (WR) and Broken Ridge (BR) for the first time. Dredged volcanic rocks were characterized using petrographic, geochemical (major and trace element, Sr‐Nd‐Pb‐Hf isotopes) and geochronological (40Ar/39Ar) techniques. Here, we focus on the sampled 82–67 Ma tholeiitic volcanic rocks. The observed geochemical data in conjunction with rare earth element inversion modeling of these Late Cretaceous volcanic rocks reflect plume–ridge interaction with variable assimilation (≤10%) of continental crust. We propose that the Kerguelen plume transported melt to the WR–BR margin during episodes of extension. Extension and magmatism were localized along the rheologically weak margins of the WR microcontinent. The combination of these mechanically weak boundaries and earlier extensional events facilitated a final ridge jump into the WR–BR margin at c. 44 Ma. We demonstrate a pre‐existing history of extension in the Late Cretaceous prior to complete fragmentation in the Eocene, resolving the apparent protracted interval between emplacement and separation of the Kerguelen LIP.
Research Findings: Executive Function (EF) skills undergo rapid development in early childhood and play a crucial role in academic success. This research investigated levels of children's EF across two samples of children from Iran (Mage = 5.80 years; N = 291, 39% girls) and the United States (Mage = 6.15 years; N = 304, 49% girls). It also examined the concurrent associations between EF skills and children's age, gender, and parental education and explored the relation between EF skills and early academic performance in both samples. Results indicated that Iranian children exhibited significantly lower EF levels than their U.S. counterparts. Older children demonstrated higher EF skills than younger children in the Iranian sample, but there was no significant association between age and EF in the U.S. sample. There were no gender differences in EF performance in either sample. Maternal education, but not paternal education, was significantly correlated with children's EF in both Iran and the U.S. Furthermore, children with higher EF showed better academic skills, with a stronger association between EF and math across both samples. Practice or Policy: The results provide valuable insights into universal and culturally specific aspects of EF development and its links to individual factors and academic performance.
The alimentary tract includes the oral cavity, esophagus, stomach, intestine, and rectum. These structures all share the same basic structure and consist of an epithelial-lined cavity supported by a submucosa. This submucosa is surrounded by bone in parts of the oral cavity and by muscle in the rest of tract. Because of this consistent basic structure, tumors that develop within the tubular alimentary tract can be subdivided into those of the epithelium and those that develop within the supporting mesenchymal tissue. Cancer staging requires assessment of regional lymph nodes for the presence of metastases. Papillomas of the oral cavity can be subdivided into squamous papillomas that are benign neoplasms and viral papillomas that are hyperplastic lesions caused by papillomavirus infection. Squamous cell carcinomas are the most common oral neoplasm of cats, horses, and the production animal species. They are the second most common malignant oral neoplasm of dogs.
