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• Transesterification catalyzed by simple alkylammonium salt and epoxide. • Various esters were synthesized from abundant methyl esters. • Ring-opening reaction of epoxide generates catalytically active base catalyst. Transesterification of methyl esters was accelerated by an in situ -generated metal-free catalyst comprising a quaternary alkylammonium salt and an epoxide. The combination of a quaternary alkylammonium acetate and glycidol is optimal, and various esters were synthesized from methyl esters with alcohols in good to excellent yield. Analysis of the catalyst solution revealed that basic species are generated by the ring-opening reaction of epoxide. [ABSTRACT FROM AUTHOR]

Despite worldwide efforts to develop technologies for autonomous vessels, large-scale implementation has yet to be achieved. This lack of achievement is not only due to technical and economic constraints but also to decision-making of individual stakeholders who may explore decisions narrowly, for example solely on the maximization of short-term profits. Therefore, it is desirable to consider other combinations of decision-making by stakeholders to break out of this situation. However, it is challenging to grasp how individual decisions affect the entire maritime industry given market, technology, and competition complexity. In this study, we examine the investment strategies that stakeholders, especially policymakers, should adopt to promote the more rapid adoption of autonomous vessels. A simulator is developed which emulates the decisions and interplay of three types of activities: research and development, manufacturing, and operational activities. Patterns of adoption due to combinations of stakeholders' decisions are predicted to delay or accelerate the introduction of automation in the maritime industry. Specifically, this study estimates that the introduction of fully autonomous vessels can be accelerated by more than ten years through a mix of subsidies for prototyping, R&D (research and development) technology, deregulation for new technology, and encouraging ship operators to make safety-centric decisions. • Large-scale implementation of autonomous vessels faces technical, economic, and decision-making challenges. • Combinations of decision-making by stakeholders need to be considered. • A simulator is developed to predict the effects of stakeholder decisions on adoption patterns. • Appropriate subsidies, deregulation, and safety-centric decisions can accelerate the adoption of autonomous vessels. [ABSTRACT FROM AUTHOR]

CO 2 capture and storage has been considered to be one of the most effective strategies against global warming, among which CO 2 storage in deep saline aquifers using the sealing effect of gas hydrate and CO 2 storage in the sub-seabed sand sediment in the form of gas hydrate are of great interest nowadays, due to the large capacity of CO 2 storage in sub-seabed sand sediments and low risk of CO 2 leakage. To access those two options, an integrated model for CO 2 hydrate formation, which includes hydrate formation rates on the gas front, on the hydrate film behind the gas front, and on the surface of the sand particles behind the gas front, is proposed in this study to predict hydrate formation morphologies in the sand sediment under the condition of gas-liquid two-phase flow. Then, numerical simulations of CO 2 hydrate formation in the sand sediment are conducted, and unknown parameters in the models are determined by comparing the simulation results with experimental data. The simulation results indicate that CO 2 hydrate formation on the hydrate film behind the gas front makes a great contribution to CO 2 hydrate saturation near the boundary, occupies the pore space of the sand sediment, and results in the permeability reduction and the blockage of the gas flow. [ABSTRACT FROM AUTHOR]

Abstract: Among several methods for CO2 capture and storage, we focus on CO2 sequestration in the form of gas hydrate under the seafloor, mainly for many sequestration sites offshore Japan and for little risk of CO2 leakage from the sediment. However, it is difficult to evaluate the precise storage potential and cost of this method due to the lack of the relevant information. Here, in order to do feasibility studies of this technique so as to make an effective storage method, we made a 3-dimentional gas water flow simulator with kinetic hydrate formation. The new design of CO2 hydrate formation in porous media under two-phase flow condition was implemented in this simulator, and unknown parameters in necessary mathematical models for gas-water flow in sand sediments were verified from the comparison between the results of the numerical simulations and the experimental measurements from the previous study. [Copyright &y& Elsevier]

Abstract: A novel photochromic 2,3-dithiazolylindole has been synthesized and its photochromic properties was elucidated. This compound showed reversible photochromism both in solution and in a crystal with no spontaneous bleaching under dark conditions. The photocyclization quantum yield of the dithiazolylindole was as high as 83% in hexane, suggesting the photoreactive conformation was stabilized through intramolecular interactions. X-ray crystal structure analysis revealed that the dithiazolylindole adopted the photoreactive conformation with quasi-C 2 symmetry around the hexatriene moiety in the crystalline state. This conformation was assisted by presumed intramolecular CH/N hydrogen bonding between the central N-methylindole and the side-chain thiazolyl units in combination with steric interactions between methyl groups at the reactive center carbons. The suggestion of intramolecular hydrogen bonding in solution was also supported by a 1H NMR variable temperature study. [Copyright &y& Elsevier]

Abstract: Absorption, CD and circularly polarized luminescence, CPL, of opaque film of a chiral fluorescent perylene derivative are studied. The aggregated state formed in the bulk film is responsible to characteristic optical dissymmetry with enhanced g lum value, which was measured by an originally designed CPL measurement system. The fluorescence emission band characteristic for the aggregated π-stacked structure revealed specific CPL activity at wavelength range longer than that of the isolated molecules. [Copyright &y& Elsevier]

This review focuses upon major achievements and recent advancements in the development of photoactive molecules which, under controlled illumination, release acidic groups either in solution or at the solid state. Successful photoacid generators are described the design of which are based on ionic, benzyl ester, imino ester, spiropyran and terarylene frameworks and the mechanism of acid generation in each case is discussed in detail. The development of such systems towards applications in lithography, surface etching, polymer design and two photon absorption processes are presented in order to give a state of the art overview of the development of new photoacid generators in the last three decades. [ABSTRACT FROM AUTHOR]

Abstract: The selective hydrogen peroxide oxidation of vinyl ethers to give acetates was developed using triphenylphosphine palladium and triethyl amine catalysts under mild reaction conditions. [Copyright &y& Elsevier]

Abstract: A series of diaryl acenaphthylenes has been synthesized, and their photochromic properties are studied both in solution and in the crystalline state. 2,4-Dimethyl-5-phenylthiophene derivative 1a showed no photochromic reaction, while 2-methyl-5-phenylthiophene derivative 2a and 5-methyl-2-phenylthiazol derivative 3a showed reversible photochromism in solution. Fluorescence spectrum of compound 3a changed upon photoirradiation. In the single-crystal state, compound 3a showed no photochromic reaction possibly because of π–π and CH/S inter-molecular interactions. The photocyclization quantum yield of 3a was determined to be as low as 0.7%. The closed-isomer 3b showed relatively high thermal stability by the rigidity of acenaphtylene. [ABSTRACT FROM AUTHOR]