27 research outputs found
Benzene-1,4-dicarboxylic acid–N,N-dimethylacetamide (1/2)
The asymmetric unit of title compound, C8H6O4·2C4H9NO, contains one half-molecule (an inversion centre in P21/n generates the other half of the molecule) of terephthalic acid (TA) and one molecule of N,N-dimethylacetamide (DMAC). The DMAC molecules are linked to TA by strong O—H⋯O hydrogen bonds
SoK: MEV Countermeasures: Theory and Practice
Blockchains offer strong security guarantees, but they cannot protect the
ordering of transactions. Powerful players, such as miners, sequencers, and
sophisticated bots, can reap significant profits by selectively including,
excluding, or re-ordering user transactions. Such profits are called
Miner/Maximal Extractable Value or MEV. MEV bears profound implications for
blockchain security and decentralization. While numerous countermeasures have
been proposed, there is no agreement on the best solution. Moreover, solutions
developed in academic literature differ quite drastically from what is widely
adopted by practitioners. For these reasons, this paper systematizes the
knowledge of the theory and practice of MEV countermeasures. The contribution
is twofold. First, we present a comprehensive taxonomy of 28 proposed MEV
countermeasures, covering four different technical directions. Secondly, we
empirically studied the most popular MEV- auction-based solution with rich
blockchain and mempool data. In addition to gaining insights into MEV auction
platforms' real-world operations, our study shed light on the prevalent
censorship by MEV auction platforms as a result of the recent OFAC sanction,
and its implication on blockchain properties
Naphthalene-2,6-dicarboxylic acid–1-methylpyrrolidin-2-one (1/2)
The asymmetric unit of the title compound, C12H8O4·2C5H9NO, contains one half-molecule of naphthalene-2,6-dicarboxylic acid (NDA) and one molecule of 1-methylpyrrolidin-2-one (NMP): the NDA molecules lie on the crystallographic twofold rotation axes. In the crystal, the components are linked by strong O—H⋯O hydrogen bonds and C—H⋯O interactions
Semicontinuous Studies on the Reaction Mechanism and Kinetics for the Liquid-Phase Oxidation of p
Isothermal Seeded Semicontinuous Reactive Crystallization of Crude Terephthalic Acid Crystals †
Propagation and control of fire front in the combustion assisted gravity drainage using horizontal wells
The propagating characteristics of combustion fronts and coke zones in the combustion assisted gravity drainage process were studied using 3D physical simulation experiments. The main mechanisms and factors affecting stable propagation of the combustion fronts were discussed. The experimental results show that the propagation of combustion front can be divided into startup stage, radial expands stage and moving forward stage. The top oil layer is ignited first at the startup stage. Ignition temperature, ignition time and air injection rate are the key parameters for successful ignition. At the radial expanding stage the combustion front grows in size and expands radically and downwards like a funnel, and the air injection rate should match the area of combustion front. After the combustion front propagates beyond the “toe” position, the burning zone would advance along the horizontal well at a certain angle. The controlled gas override and gas seal of the coke in the horizontal well contributes significantly to the overall stability of the process. In field pilot testing, well pattern, ignition parameters and regime of injection and production should be optimized to ensure the stable propagation of the combustion front. Key words: combustion assisted gravity drainage, horizontal well, combustion front, propagating characteristic, physical simulatio