Mức methane hiện tại cao vượt trội so với kịch bản có khả năng hạn chế mức tăng nhiệt độ trái đất trong khoảng 1,5-2°C.

Do xu hướng biến thiên mật độ methane trong bầu khí quyển vẫn còn thiếu hụt, do đó bài nghiên cứu của Skeie, Hodnebrog & Myhre (2023) trên tạp chí Communications Earth & Environment sẽ giúp ta hiểu thêm một số điểm quan trọng.

My objective is a better comprehension of two theoretically fundamental concepts. One, the concept of a substance in an ordinary (non-Aristotelian) sense, ranging over such things as salt, carbon, copper, iron, water, and methane – kinds of stuff that now count as (chemical) elements and compounds. The other I’ll call the object-concept in the abstract sense of Russell, Wittgenstein, and Frege in their logico-semantical enquiries. The material object-concept constitutes the heart of our received logico / ontic system, still massively (...) influenced by Aristotle after almost 2.5 millennia. On such an account, the fundamentality of material objects and their attributes are the metaphysical basis of the cosmos, as reflected in our received logic, Quine’s ‘canonical notation’ – derived via the empiricism of Russell from Frege’s function-based Begriffschrifft, and consisting of concrete singular terms and variables, quantifiers and predicate-expressions. The inadequacy of Frege’s approach to understanding concepts is reflected in his initial question. Frege enquires of ‘what it is that we are calling an object’, remarking that he regards a regular definition as impossible: “we have here something too simple to admit of logical analysis”. The imagined ultimacy or simplicity of the idea of a single object (arithmetically, just a unit – one as against two, three, four, etc.) as foundational to the calculus is just that – imagined. It is also guaranteed to block the comprehension of the substance-concept. (shrink)

This paper investigates a well-known case of simultaneous discovery in twentieth-century chemistry, the origins of the concept of hybridisation, in the light of Kuhn's insights. There has been no ambiguity as to who discovered this concept, when it was "rst in print, and how important it was. The full-#edged form of the concept was published in 1931 independently by two American scientists John C. Slater (1900}1976) and Linus Pauling (1901}1994), although both of them had made their ideas public earlier: Slater (...) at the American Physical Society meetings in 1930, and Pauling in the Proceedings of the National Academy of Sciences in 1928. Slater and Pauling both argued for the necessity of using an s orbital as well as three p orbitals in the carbon atom in order to explain carbon's four valences and the tetrahedral structure of methane. The metaphor &hybridisation' for denoting this mix of s and p orbitals was "rst used by Robert S. Mulliken and J. H. Van Vleck before gaining currency with the scienti"c community around 1935.2 The concept of hybridisation was indeed indispensable for extending the quantum-mechanical interpretation of the chemical bond as an electron pairing from diatomic molecules to polyatomic ones. To be sure, the emergence of hybridisation attests to scientists' growing interest in exploring the borderland between physics and chemistry, a trend that led to the creation of physical chemistry in the late nineteenth century and of chemical physics and quantum chemistry in the 1920s and 30s. Slater and Pauling themselves experienced and on many occasions talked about the fruitfulness of interdisciplinary research; and historians have legitimately illuminated their works by examining them in this broad context.3 Yet the careful analysis of their research notes and published papers reveals that Slater and Pauling were working in quite disparate disciplinary traditions, with di!erent approaches, for di!erent audiences, and towards di!erent goals. The aim of this paper is to explore their di!erent routes to a common destination*hybridisation*and thereby to explicate tensions existing between physics and chemistry amidst the institutional and conceptual overlapping of the two disciplines. (shrink)

In recent decades, the use of electrochemistry has increased exponentially. Electrochemistry has demonstrated their effectiveness in the cleaning of manufactured effluents and the decomposition of complex hydrological compounds for water treatment. Looking at the efficiency of the technology in the decomposition of organic matter, one wonders if it is not capable of doing more than just the de-pollution and treatment of water. Of course, there are other uses of electrochemistry, but in the literature, it is understood that it is used (...) more for water treatment and de-pollution. This work is a review of the literature to identify the major works in electrochemical decomposition of organic matter to see to what extent this technology can be used for methane production (cooking gas) using pasty organic matter. The list of works appearing in this review is not exhaustive, but it is sufficient to give a clear idea of the technology, its progress and, above all, the challenges it faces. This review opens the way to other applications of electrochemical decomposition to meet today's energy challenges. (shrink)